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  • 151.
    Kavvalos, Mavroudis
    et al.
    Mälardalen University, School of Business, Society and Engineering, Future Energy Center.
    Kyprianidis, Konstantinos
    Mälardalen University, School of Business, Society and Engineering, Future Energy Center.
    Padulo, M.
    AURA-AERO, Cugnaux, 312 70, France.
    The Growth Engine Concept and Its Potential for an Electrified Aviation Future2024In: Journal of engineering for gas turbines and power, ISSN 0742-4795, E-ISSN 1528-8919, Vol. 146, no 7, article id 070901Article in journal (Refereed)
    Abstract [en]

    The emerging need for cost- and energy-efficient propulsion systems have shifted the research interest to radical concepts, with several challenges to overcome in order to enter into service. However, revitalizing old yet provably successful engine designs-a practice followed by engine manufacturers over the years-can provide low-risk alternative solutions to move immediate market demands. The paper reviews this approach, known as concept of growth engines or core commonality, and investigates how a geometrically fixed or geometrically similar engine core can be utilized across a family of engines. The development programs of the highly successful CFM56 and PT6 engine families are analyzed, proving the success of this concept over the years. The idea is based on the engineering paradigm of product families and is briefly presented from a theoretical perspective. Implementation methods and simulation tools to initiate, conceptualize, design, and evaluate an engine family program are reviewed. The potential application of engine core commonality into electrified propulsion systems is investigated. Design challenges and opportunities that electrification imposes to the growth engine concept are discussed. Finally, the concept of growth electrified propulsion systems is introduced, conveying future research directions to achieve a successful family of engines for electrified applications.

  • 152.
    Khan, Zarrar
    et al.
    Pacific Northwest Natl Lab PNNL, Joint Global Change Res Inst JGCRI, College Pk, MD 20740 USA..
    Abraham, Edo
    Delft Univ Technol, Dept Water Resources Management, Delft, Netherlands..
    Aggarwal, Srijan
    Univ Alaska Fairbanks, Coll Engn & Mines, Fairbanks, AK USA..
    Khan, Manal Ahmad
    Natl Geog Partners, Washington, DC USA..
    Arguello, Ricardo
    Unidad Planificac Rural Agr UPRA, Bogota, Colombia..
    Babbar-Sebens, Meghna
    Oregon State Univ, Sch Civil & Construct Engn, Coll Engn, Corvallis, OR 97331 USA..
    Bereslawski, Julia Lacal
    Banco Interamer Desarrollo, Buenos Aires, DF, Argentina..
    Bielicki, Jeffrey M.
    Ohio State Univ, Dept Civil Environm & Geodet Engn, Columbus, OH 43210 USA.;Ohio State Univ, John Glenn Coll Publ Affairs, Columbus, OH 43210 USA..
    Campana, Pietro Elia
    Mälardalen University, School of Business, Society and Engineering, Future Energy Center.
    Carrazzone, Maria Eugenia Silva
    FAO, Rome, Italy..
    Emerging Themes and Future Directions of Multi-Sector Nexus Research and Implementation2022In: Frontiers in Environmental Science, E-ISSN 2296-665X, Vol. 10, article id 918085Article in journal (Refereed)
    Abstract [en]

    Water, energy, and food are all essential components of human societies. Collectively, their respective resource systems are interconnected in what is called the "nexus". There is growing consensus that a holistic understanding of the interdependencies and trade-offs between these sectors and other related systems is critical to solving many of the global challenges they present. While nexus research has grown exponentially since 2011, there is no unified, overarching approach, and the implementation of concepts remains hampered by the lack of clear case studies. Here, we present the results of a collaborative thought exercise involving 75 scientists and summarize them into 10 key recommendations covering: the most critical nexus issues of today, emerging themes, and where future efforts should be directed. We conclude that a nexus community of practice to promote open communication among researchers, to maintain and share standardized datasets, and to develop applied case studies will facilitate transparent comparisons of models and encourage the adoption of nexus approaches in practice.

  • 153.
    Klintenberg, P.
    et al.
    Blekinge Institute of Technology, Department of Spatial Planning, Karlskrona, Sweden.
    Mabecua, Fastudo Jorge
    Mälardalen University, School of Business, Society and Engineering, Future Energy Center.
    Schwede, Sebastian
    Mälardalen University, School of Business, Society and Engineering, Future Energy Center.
    Is small-scale biogas production a viable source of electricity in rural Sub-Saharan Africa?2024In: Energy Proceedings, Scanditale AB , 2024, Vol. 42Conference paper (Refereed)
    Abstract [en]

    This study investigates the benefits and limitations of small-scale biogas technology at the household level in rural Sub-Saharan Africa. A literature study and a case study were done to explore if small-scale biogas production is a viable source of electricity in rural Sub-Saharan Africa. The results show that using cattle manure as feedstock requires a daily substrate flow of 750 L of the diluted substrate, i.e. 250 kg of manure and 500 L of water for a 24-hour electricity supply, using a 2-kW generator. This requires a minimum herd size of 25 cattle. Most households don’t have so many cattle. However, a herd of 10 cattle provides enough biogas to power several electrical appliances, significantly improving the household's energy situation. The study concludes that the uptake of biogas technology in Sub-Saharan Africa is slow. Common barriers include inadequate substrate supply, lack of water and variable temperatures, high initial costs, poor technical quality, intense labour operations and maintenance, and insufficient policy support. Improved uptake of biogas technology in Sub-Saharan Africa requires establishing national institutional frameworks and supporting policies, collaboration with the intended users of the technology and local support organisations, ensuring long-term local availability of spare parts and supplies, and, when household-level access to feedstock is limited, centralise biogas systems on the village level to combine feedstock into one production system.

  • 154.
    Krayem, Alaa
    et al.
    Mälardalen University, School of Business, Society and Engineering, Future Energy Center.
    Thorin, Eva
    Mälardalen University, School of Business, Society and Engineering, Future Energy Center.
    Wallin, Fredrik
    Mälardalen University, School of Business, Society and Engineering, Future Energy Center.
    Experiences from developing an open urban data portal for collaborative research and innovation2024In: Applied Energy, ISSN 0306-2619, E-ISSN 1872-9118, Vol. 355, article id 122270Article in journal (Refereed)
    Abstract [en]

    The energy transition towards sustainable resources is more urgent than ever given the environmental and geopolitical challenges. Being one of the major energy users, cities need to understand their energy sector to accomplish its transition, by means of data. However, data are not easily accessible and have their own challenges. This paper presents a joint effort between researchers, city representatives and industry to provide an urban system service that supports research, accelerates urban innovation, and involves the community. An energy data portal, “NRGYHUB”, has been developed, where hourly data from thousands of energy meters are available. These meters were collected from neighborhoods in the city of Västerås, Sweden, and they measure electrical and heating energy. In addition, the data are complemented by geometrical and non-geometrical information of the buildings, as well as demographic statistics of the areas. The paper describes the process of data collection, preprocessing, and visualization, in addition to the main challenges and limitations of the project. This dataset can be used for energy use benchmarking, prediction, and analysis. 

  • 155.
    Leithaeuser, Anna
    et al.
    Ruhr University Bochum, Thermodynamics, Universitätsstraße 150, Bochum, 44780, Germany.
    Gerber, Mandy
    Bochum University of Applied Science, Thermodynamics, Bochum, 44801, Germany.
    Span, Roland
    Ruhr University Bochum, Thermodynamics, Universitätsstraße 150, Bochum, 44780, Germany.
    Schwede, Sebastian
    Mälardalen University, School of Business, Society and Engineering, Future Energy Center.
    Comparison of pyrochar, hydrochar and lignite as additive in anaerobic digestion and NH4+ adsorbent2022In: Bioresource Technology, ISSN 0960-8524, E-ISSN 1873-2976, Vol. 361, article id 127674Article in journal (Refereed)
    Abstract [en]

    The impact of pyrochar, hydrochar and lignite addition on anaerobic digestion of food waste was investigated with and without ammonia inhibition under batch conditions. Furthermore, ammonium adsorption capacities of the chars were investigated. To determine anaerobic degradation of char, reference samples containing inoculum and char were analyzed, indicating a significant degradation of hydrochar. Depending on the evaluation method, the increase in methane yield due to hydrochar addition varied between no statistically significant difference and +14 %. No significant impact due to the addition of 5 g/l pyrochar and lignite on AD was found. NH4+ adsorption capacities showed a significantly higher net adsorption capacity of lignite (1.58 mgNH4+/gL), compared to pyrochar (0.63 mgNH4+/gPC). A negative NH4+ adsorption capacity (−0.51 mgNH4+/gHC) was found for hydrochar. A high H/C-ratio, O/C-ratio and cation exchange capacity of hydrochar and lignite indicate many functional groups and low chemical stability, enabling an increased interaction between NH4+ and char.

  • 156.
    Li, F.
    et al.
    Energy Engineering, Division of Energy Science, Luleå University of Technology, Luleå, 97187, Sweden.
    Li, Y.
    Energy Engineering, Division of Energy Science, Luleå University of Technology, Luleå, 97187, Sweden.
    Cao, J.
    State Key Laboratory of Materials-Oriented and Chemical Engineering, Nanjing Tech University, Nanjing, 211816, China.
    Carvalho, Lara
    Mälardalen University, School of Business, Society and Engineering, Future Energy Center.
    Lundgren, J.
    Energy Engineering, Division of Energy Science, Luleå University of Technology, Luleå, 97187, Sweden. Department of Chemical Engineering and Technology, Chemical Technology, KTH Royal University of Technology, Stockholm, 10044, Sweden.
    Engvall, K.
    Energy Engineering, Division of Energy Science, Luleå University of Technology, Luleå, 97187, Sweden. Department of Chemical Engineering and Technology, Chemical Technology, KTH Royal University of Technology, Stockholm, 10044, Sweden..
    Zhang, X.
    Beijing Key Laboratory of Ionic Liquids Clean Process, State Key Laboratory of Multiphase Complex Systems, CAS Key Laboratory of Green Process and Engineering, Institute of Process Engineering, Chinese Academy of Sciences, Beijing, 100190, China.
    Liu, Y.
    Beijing Key Laboratory of Ionic Liquids Clean Process, State Key Laboratory of Multiphase Complex Systems, CAS Key Laboratory of Green Process and Engineering, Institute of Process Engineering, Chinese Academy of Sciences, Beijing, 100190, China.
    Ji, X.
    Energy Engineering, Division of Energy Science, Luleå University of Technology, Luleå, 97187, Sweden.
    Combination of CO2 electrochemical reduction and biomass gasification for producing methanol: A techno-economic assessment2024In: Energy Conversion and Management, ISSN 0196-8904, E-ISSN 1879-2227, Vol. 307, article id 118380Article in journal (Refereed)
    Abstract [en]

    Combining CO2 electrochemical reduction (CO2R) and biomass gasification for producing methanol (CH3OH) is a promising option to increase the carbon efficiency, reduce total production cost (TPC), and realize the utilization of byproducts of CO2R system, but its viability has not been studied. In this work, systematic techno-economic assessments for the processes that combined CO2R to produce CO/syngas/CH3OH with biomass gasification were conducted and compared to stand-alone biomass gasification and CO2R processes, to identify the benefits and analyze the commercialization potential of different pathways under current and future conditions. The results demonstrated that the process that combined biomass gasification with CO2R to CO represents a viable pathway with a competitive TPC of 0.39 €/kg-CH3OH under the current condition. For all the combined cases, electricity usage for CO2R accounts for 36–76% of total operating cost, which plays a key role for TPC. Sensitivity analysis confirmed that the process that combined biomass gasification with CO2R to CO is sensitive to the price of electricity, while both CO2R performance and prices of stack and electricity are important for the processes that combined with CO2R to syngas/CH3OH.

  • 157.
    Li, H.
    et al.
    Research Group of Soil Fertility and Nutrient Management, Department of Environment, Ghent University, Coupure Links 653, Ghent, 9000, Belgium.
    Françoys, A.
    Isotope Bioscience Laboratory, Department of Green Chemistry and Technology, Ghent University, Coupure Links 653, Ghent, 9000, Belgium.
    Wang, Xiaolin
    Mälardalen University, School of Business, Society and Engineering, Future Energy Center.
    Zhang, S.
    SLU Swedish Species Information Center, Swedish University of Agricultural Sciences, Uppsala, 75007, Sweden.
    Mendoza, O.
    School of Architecture, Civil and Environmental Engineering EPFL, Lausanne, 1015, Switzerland.
    De Neve, S.
    Research Group of Soil Fertility and Nutrient Management, Department of Environment, Ghent University, Coupure Links 653, Ghent, 9000, Belgium.
    Dewitte, K.
    Department of Plants and Crops, Ghent University, Coupure Links 653, Ghent, 9000, Belgium.
    Sleutel, S.
    Research Group of Soil Fertility and Nutrient Management, Department of Environment, Ghent University, Coupure Links 653, Ghent, 9000, Belgium.
    Field-scale assessment of direct and indirect effects of soil texture on organic matter mineralization during a dry summer2023In: Science of the Total Environment, ISSN 0048-9697, E-ISSN 1879-1026, Vol. 899, article id 165749Article in journal (Refereed)
    Abstract [en]

    Soil texture plays a crucial role in organic matter (OM) mineralization through both direct interactions with minerals and indirect effects on soil moisture. Separating these effects could enhance the modelling of soil organic carbon (SOC) dynamics under climate change scenarios. However, the attempts have been limited small-scale experiments. Here, we studied the effects of soil texture on added OM mineralization in loamy sand, loam and silt loam soils in nine agricultural fields in Flanders, Belgium. Soil moisture, temperature, groundwater table depth and the mineralization of 13C-labeled ryegrass were monitored in buried mesocosms for approximately three months during a dry summer. Ryegrass-C mineralization was lowest in the loamy sand (39 ± 7 %) followed by silt loam (48 ± 7 %) and loam (63 ± 5 %) soils, challenging the current clay%-based moderation of C-mineralization rates in soil models. Soil temperature was not influenced by soil texture, whereas soil moisture was indeed dependent on soil texture. It appears that capillarity sustained upward water supply from groundwater to the topsoil in loam and silt loam soils but not in loamy sand soil, although this difference in capillary rise could not fully explain the higher moisture content in loam than that in silt loam soils. Additionally, soil texture only impacted remnant added ryegrass pieces (>500 μm) but not the finer ryegrass-derived SOC (<500 μm), which might point at the important indirect control of texture on OM mineralization during prolonged summer drought. However, these effects are only manifested during drought when no other factors (e.g., groundwater depth or subsurface water flows) exert an overriding impact on the soil water balance. Overall, our findings highlight the need to properly incorporate the indirect effects of soil texture on OM mineralization into soil carbon models to accurately predict soil C stocks under future climate change scenarios.

  • 158.
    Li, Houpei
    et al.
    College of Civil Engineering, Hunan University, Changsha, 410082, China; Key Laboratory of Building Safety and Energy Efficiency of the Ministry of Education, Changsha, China.
    Li, Jun
    Department of Materials Science and Engineering, University of Michigan, Ann Arbor, 48109, MI, United States.
    Li, Sihui
    College of Civil Engineering, Hunan University, Changsha, 410082, China; Key Laboratory of Building Safety and Energy Efficiency of the Ministry of Education, Changsha, China.
    Peng, Jinqing
    College of Civil Engineering, Hunan University, Changsha, 410082, China; Key Laboratory of Building Safety and Energy Efficiency of the Ministry of Education, Changsha, China.
    Ji, Jie
    Department of Thermal Science and Energy Engineering, University of Science and Technology of China, Hefei, China.
    Yan, Jinyue
    Mälardalen University, School of Business, Society and Engineering, Future Energy Center.
    Matching characteristics and AC performance of the photovoltaic-driven air conditioning system2023In: Energy, ISSN 0360-5442, E-ISSN 1873-6785, Vol. 264, article id 126509Article in journal (Refereed)
    Abstract [en]

    Photovoltaic-driven Air Conditioning systems (PVAC) use local electricity generated by distributed Photovoltaic (PV) to drive Air Conditioners (AC). Both the AC cooling load and the PV electricity generation are affected by solar radiation. The PV generation cannot dynamically supply the AC power consumption during the operation. In this study, the matching characteristics of a PVAC were investigated using a case in a 207.34 m2 office room. A coupled simulation model was built, which integrated with a building model, a PV calculation model, an AC model, and a control strategy. More specifically, the AC was modeled with two heat exchangers, a compressor, and a throttling device. Both the building and the PV were simulated in EnergyPlus. The AC compressor speed was controlled so the AC power consumption could match the PV generation when the indoor temperature was within the temperature control zone. The daily matching characteristics of PVAC were strongly affected by the PV capacity. The results showed that the PV factor (PVF) should be set to 1 in order to match the AC and PV power and maximize the AC efficiency. A battery factor of at least 0.7 could ensure the grid flexibility. Finally, the optimized design of PV, battery, and AC capacities was suggested.

  • 159.
    Li, Peiran
    et al.
    The University of Tokyo, Japan.
    Zhang, Haoran
    Mälardalen University, School of Business, Society and Engineering, Future Energy Center. The University of Tokyo, Japan.
    Guo, Zhiling
    The University of Tokyo, Japan.
    Lyu, Suxing
    The University of Tokyo, Japan.
    Chen, Jinyu
    The University of Tokyo, Japan.
    Li, Wenjing
    The University of Tokyo, Japan.
    Song, Xuan
    SUSTech-UTokyo Joint Research Center on Super Smart City, Department of Computer Science and Engineering, Southern University of Science and Technology (SUSTech), Shenzhen, China.
    Shibasaki, Ryosuke
    The University of Tokyo, Japan.
    Yan, Jinyue
    Mälardalen University, School of Business, Society and Engineering, Future Energy Center.
    Understanding rooftop PV panel semantic segmentation of satellite and aerial images for better using machine learning2021In: Advances in Applied Energy, ISSN 2666-7924, Vol. 4, p. 100057-100057, article id 100057Article in journal (Refereed)
    Abstract [en]

    The photovoltaic (PV) industry boom and increased PV applications call for better planning based on accurate and updated data on the installed capacity. Compared with the manual statistical approach, which is often time-consuming and labor-intensive, using satellite/aerial images to estimate the existing PV installed capacity offers a new method with cost-effective and data-consistent features. Previous studies investigated the feasibility of segmenting PV panels from images involving machine learning technologies. However, due to the particular characteristics of PV panel semantic-segmentation, the machine learning tools need to be designed and applied with careful considerations of the issue formulation, data quality, and model explainability. This paper investigated the characteristics of PV panel semantic-segmentation from the perspective of computer vision. The results reveal that the PV panel image data has several specific characteristics: highly class-imbalance and non-concentrated distribution; homogeneous texture and heterogenous color features; and the notable resolution threshold for effective semantic-segmentation. Moreover, this paper provided recommendations for data obtaining and model design, aiming at each observed character from the viewpoints of recent solutions in computer vision, which can be helpful for future improvement of the PV panel semantic-segmentation.

  • 160.
    Li, Shuangjun
    et al.
    Tianjin Univ, Tianjin, Peoples R China.;Korea Univ, Seoul, South Korea..
    Cho, Moon-Kyung
    Korea Univ, Seoul, South Korea..
    Yuan, Xiangzhou
    Korea Univ, Seoul, South Korea.;Sun Brand Ind Inc, South Korea..
    Deng, Shuai
    Tianjin Univ, Tianjin, Peoples R China..
    Li, Hailong
    Mälardalen University, School of Business, Society and Engineering, Future Energy Center.
    Zhao, Li
    Tianjin Univ, Tianjin, Peoples R China..
    Zhao, Ruikai
    Tianjin Univ, Tianjin, Peoples R China..
    Wang, Yuzhen
    Tianjin Univ, Tianjin, Peoples R China..
    Wang, Junyao
    Sun Yat Sen Univ, Guangdong, Peoples R China..
    Lee, Ki Bong
    Korea Univ, Seoul, South Korea..
    Cyclic performance evaluation of CO2 adsorption using polyethylene terephthalate plastic-waste-derived activated carbon2023In: Fuel, ISSN 0016-2361, E-ISSN 1873-7153, Vol. 331, article id 125599Article in journal (Refereed)
    Abstract [en]

    Polyethylene terephthalate (PET) plastic-waste-derived activated carbons have recently been developed and exhibit excellent CO(2 )adsorption uptake. However, the CO2-adsorption performance of such recycled materials has only been considered on a basic characterization level and has not yet been evaluated in carbon capture cycles, thereby making biased analyses inevitable. Consequently, a whole chain including the material, process, and cycle is essential for comprehensively analyzing and evaluating novel CO2 adsorbents. Therefore, in this study, various CO2-capture cycles using PET plastic-waste-derived activated carbon adsorbents were numerically simulated, the cyclic CO2-adsorption performances were evaluated, and the application scenario was optimized. A methodology for evaluating the cyclic CO2-adsorption performance of PET plastic-waste-derived activated carbon was proposed for CO(2 )capture. The results suggested that the temperature/vacuum swing adsorption cycle was superior and that its maximum exergy efficiency reached 32.90%.

  • 161.
    Li, Wenjing
    et al.
    Univ Tokyo, Ctr Spatial Informat Sci, Kashiwa, Chiba 2770882, Japan.;Univ Tokyo, Informat Technol Ctr, Kashiwa, Chiba 2770882, Japan..
    Shi, Xiaodan
    Mälardalen University, School of Business, Society and Engineering, Future Energy Center. Univ Tokyo, Ctr Spatial Informat Sci, Kashiwa, Chiba 2770882, Japan..
    Huang, Dou
    Univ Tokyo, Ctr Spatial Informat Sci, Kashiwa, Chiba 2770882, Japan.;Locat Mind Inc, Tokyo 1010048, Japan..
    Shen, Xudong
    Univ Tokyo, Ctr Spatial Informat Sci, Kashiwa, Chiba 2770882, Japan..
    Chen, Jinyu
    Univ Tokyo, Ctr Spatial Informat Sci, Kashiwa, Chiba 2770882, Japan..
    Kobayashi, Hill Hiroki
    Univ Tokyo, Ctr Spatial Informat Sci, Kashiwa, Chiba 2770882, Japan.;Univ Tokyo, Informat Technol Ctr, Kashiwa, Chiba 2770882, Japan..
    Zhang, Haoran
    Peking Univ, Sch Urban Planning & Design, Shenzhen 518055, Guangdong, Peoples R China..
    Song, Xuan
    Univ Tokyo, Ctr Spatial Informat Sci, Kashiwa, Chiba 2770882, Japan.;Southern Univ Sci & Technol, Southern Univ Sci & Technol Univ Tokyo Joint Res, Dept Comp & Engn, Shenzhen 518055, Guangdong, Peoples R China..
    Shibasaki, Ryosuke
    Univ Tokyo, Interfac Initiat Informat Studies, Tokyo 1138654, Japan.;Reitaku Univ, Kashiwa, Chiba 2770065, Japan..
    PredLife: Predicting Fine-Grained Future Activity Patterns2023In: IEEE Transactions on Big Data, E-ISSN 2332-7790, Vol. 9, no 6, p. 1658-1669Article in journal (Refereed)
    Abstract [en]

    Activity pattern prediction is a critical part of urban computing, urban planning, intelligent transportation, and so on. Based on a dataset with more than 10 million GPS trajectory records collected by mobile sensors, this research proposed a CNN-BiLSTM-VAE-ATT-based encoder-decoder model for fine-grained individual activity sequence prediction. The model combines the long-term and short-term dependencies crosswise and also considers randomness, diversity, and uncertainty of individual activity patterns. The proposed results show higher accuracy compared to the ten baselines. The model can generate high diversity results while approximating the original activity patterns distribution. Moreover, the model also has interpretability in revealing the time dependency importance of the activity pattern prediction.

  • 162.
    Li, Xueqiang
    et al.
    Tianjin University of Commerce, China.
    Qin, Song
    Tianjin University of Commerce, China.
    Li, Hailong
    Mälardalen University, School of Business, Society and Engineering, Future Energy Center. Tianjin University of Commerce, China.
    Liu, Shengchun
    Tianjin University of Commerce, China.
    Wang, Yabo
    Tianjin University of Commerce, China.
    Key factors affecting the performance of the multi-stream heat exchanger for CO2 condensation2023In: International journal of thermal sciences, ISSN 1290-0729, E-ISSN 1778-4166, Vol. 192, article id 108377Article in journal (Refereed)
    Abstract [en]

    The multi-stream heat exchanger (MS-HEX) is an important equipment in CO2 capture processes, especially for CO2 condensation. By now, little attention has been paid to thoroughly investigating its performance. To provide insights for optimizing the design and operation of the MS-HEX, this paper evaluated the impacts of some key factors, such as the flow arrangement and the content of non-condensable (NC) gases, on the performances of the MS-HEX, including the exit vapor fraction, the pressure drop, the heat transfer coefficient (HTC), and the sub-cooling degree. A 3D CFD model was developed and validated. Based on simulations, it was found that the flow arrangement can clearly affect the performance of the MS-HEX, and there existed an optimal one, which can give the highest sub-cooling degree. Moreover, increasing the volume fraction of NC gases can lead to a decrease of the HTC and the sub-cooling degree; and Ar showed the biggest impact, followed by O2 and N2. For instance, compared to condensing a stream containing 5 vol % N2, condensing a stream containing 5 vol % Ar led to a lower HTC and a lower sub-cooling degree, which can be up to 27.3% and 4 K, respectively.

  • 163.
    Li, Xueqiang
    et al.
    Tianjin University of Commerce, China.
    Song, Wenlei
    Tianjin University of Commerce, China.
    Wang, Qihui
    Tianjin University of Commerce, China.
    Li, Hailong
    Mälardalen University, School of Business, Society and Engineering, Future Energy Center.
    Ding, Xiaofeng
    Beihang University, China.
    Liu, Shengchun
    Tianjin University of Commerce, China.
    Optimizing cooling electronic chips at high altitude with consideration of solar radiation2023In: International journal of thermal sciences, ISSN 1290-0729, E-ISSN 1778-4166, Vol. 183, article id 107879Article in journal (Refereed)
    Abstract [en]

    Maintaining a proper working environment for electronic chips is challenging for airships, as the ambient parameters at high altitude are largely different from those on the ground, which can influence the performance of cooling. This work aims to optimize the finned sink to minimize the weight with the consideration of the impact of solar radiation. By using a validated 3D model, it was found that the ignorance of the solar radiation can lead to a temperature deviation of 4.1 °C for electronic chips at 20 km when the solar radiation intensity was 1400 W/m2 and the wind speed was 10 m/s. Meanwhile, compared to the solar radiation intensity and the emissivity, the direction of solar radiation showed more impacts. In addition, even though the solar radiation doesn't influence the optimal fin height, fin number, and fin thickness, it would clearly affect the optimal heat transfer area ratio. As a result, it can clearly change the optimized weight, which was 5.7% higher if the solar radiation was not considered. © 2022 The Authors

  • 164.
    Li, Y.
    et al.
    Group of the Building Energy & Sustainability Technology, School of Human Settlements and Civil Engineering Xi’an Jiaotong University, Xi’an, 710049, China.
    Hu, R.
    Group of the Building Energy & Sustainability Technology, School of Human Settlements and Civil Engineering Xi’an Jiaotong University, Xi’an, 710049, China.
    Yang, X.
    Group of the Building Energy & Sustainability Technology, School of Human Settlements and Civil Engineering Xi’an Jiaotong University, Xi’an, 710049, China.
    Yan, Jinyue
    Mälardalen University, School of Business, Society and Engineering, Future Energy Center.
    The effect of changing PCM distribution on thermal performance of latent heat storage2022In: Energy Proceedings, Scanditale AB , 2022, Vol. 25Conference paper (Refereed)
    Abstract [en]

    In previous studies on thermal performance of solid-liquid phase change thermal energy storage (TES), it could be found that the lower phase change material (PCM) of TES was difficult to melt due to the influence of natural convection. Therefore, many scholars improved the overall thermal performance by enhancing the heat transfer in the lower region, increasing the distribution of the lower fins, increasing the length of the lower fins, or changing the porosity of the lower metal foam to improve the lower heat transfer. However, it had not been found that by changing the ratio of the upper and lower PCM to improve the heat storage performance. Therefore, this paper designed ten cases to study the effect of different ratios of the upper and lower PCM on the heat storage performance and finally found that the case 2 performed best, and the full melting time is 17240 s, reduced 39.05% compared with 28290 s of case 6.

  • 165.
    Li, Y.
    et al.
    School of Business, Shandong University at Weihai, Weihai, 264209, China.
    Ke, X.
    School of Business, Shandong University at Weihai, Weihai, 264209, China.
    Guo, Z.
    School of Business, Shandong University at Weihai, Weihai, 264209, China.
    Wang, Z.
    School of Business, Shandong University at Weihai, Weihai, 264209, China.
    Qu, S.
    School of Business, Shandong University at Weihai, Weihai, 264209, China.
    Jiang, Mingkun
    Mälardalen University, School of Business, Society and Engineering, Future Energy Center. Key Laboratory of Pressure Systems and Safety (MOE), School of Mechanical and Power Engineering, East China University of Science and Technology, Shanghai, 200237, China.
    Yan, Jinyue
    Mälardalen University, School of Business, Society and Engineering, Future Energy Center.
    Study on Environmental and Economic Benefits of Photovoltaic integration with Iron and Steel Plants in Hebei Province2021In: Energy Proceedings, Scanditale AB , 2021, Vol. 15Conference paper (Refereed)
    Abstract [en]

    Under the strategic goal of "peak carbon dioxide emissions and carbon neutrality" in China, industries with high energy consumption and high pollution, such as iron and steel plants, are facing great pressure of energy conservation and emission reduction, and are in urgent need of green and low-carbon transformation. In this paper, 46 iron and steel plants in Hebei province are taken as examples. GIS spatial analysis and environmental emission list method are used to build a comprehensive evaluation model of rooftop photovoltaic, and to calculate the technical potential, energy saving and emission reduction benefits and economic feasibility of deploying rooftop photovoltaic in iron and steel plants. Finally, carbon trading mechanism is introduced to analyze its impact on the carbon trading market. It is found that 46 iron and steel plants save 216,700 tons of standard coal, reduce 144,700 tons of CO2 emissions and reduce 1,500 tons of SO2, NOX, PM and other air pollutants every year. The economic benefit of power generation self-use mode is greater than that of grid-fed mode, with an average return on investment of 140% and a payback period of 5.5 years. The results verify that rooftop photovoltaic in iron and steel plants has dual benefits of energy saving and emission reduction and economy, and this data can provide a feasible path for iron and steel plants to use photovoltaic for green and low-carbon transformation.

  • 166.
    Li, Yuanji
    et al.
    Xi An Jiao Tong Univ, Inst Bldg Environm & Sustainabil Technol, Sch Human Settlements & Civil Engn, Xian 710049, Peoples R China.
    Niu, Zhaoyang
    Xi An Jiao Tong Univ, Inst Bldg Environm & Sustainabil Technol, Sch Human Settlements & Civil Engn, Xian 710049, Peoples R China.
    Gao, Xinyu
    Xi An Jiao Tong Univ, Inst Bldg Environm & Sustainabil Technol, Sch Human Settlements & Civil Engn, Xian 710049, Peoples R China.
    Ji, Ruiyang
    Xi An Jiao Tong Univ, Inst Bldg Environm & Sustainabil Technol, Sch Human Settlements & Civil Engn, Xian 710049, Peoples R China.
    Yang, Xiaohu
    Xi An Jiao Tong Univ, Inst Bldg Environm & Sustainabil Technol, Sch Human Settlements & Civil Engn, Xian 710049, Peoples R China.
    Yan, Jinyue
    Mälardalen University, School of Business, Society and Engineering, Future Energy Center. Hong Kong Polytech Univ, Dept Bldg Environm & Energy Engn, Kowloon, Hong Kong, Peoples R China .
    Experimental and numerical investigations on tilt filling design of metal foam in a heat storage tank2023In: Renewable energy, ISSN 0960-1481, E-ISSN 1879-0682, Vol. 217, article id 119167Article in journal (Refereed)
    Abstract [en]

    The use of metal foam as a filler in heat storage tanks proves advantageous in compensating for the low thermal conductivity of phase change materials. However, the filling of metal foam can impede natural convection within the tank. Partially filled metal foam enables both strong natural convection in the upper pure phase change material region and enhanced thermal conductivity of the metal foam. This paper proposes inclining the upper surface of the metal foam to further strengthen natural convection in the upper region. Following experimental verification, a series of heat storage tanks with different metal foam inclination forms for latent heat storage were numerically simulated and compared. The results indicate that complete melting time was shortest for the case 5 (ab-type model with a = 0, b = 91.8), at 5320s, which represents an 18.8% reduction compared to benchmark case 9. Furthermore, comparison of the cases with inclined upper surfaces indicated that the clockwise inclination pattern resulted in greater time savings than the counterclockwise pattern. The results of this study offer valuable insights for the design of partially filled heat storage tanks.

  • 167.
    Lindell, Eva
    et al.
    Mälardalen University, School of Business, Society and Engineering, Future Energy Center.
    Crevani, Lucia
    Mälardalen University, School of Business, Society and Engineering, Industrial Economics and Organisation.
    Employers’ Relational Work on Social Media2022In: Nordic Journal of Working Life Studies, E-ISSN 2245-0157, Vol. 12, no 3, p. 63-82Article in journal (Refereed)
    Abstract [en]

    Given how social media are commonly used in contemporary Nordic countries, social media platforms are emerging as crucial for relational work between employers, employees, and potential employees. By means of a discursive psychology approach, this study investigates employers’ constructs of relational work on social media through the use of two interpretative repertoires: the repertoire of loss of control and the repertoire of ever-presence. The consequences of these interpretative repertoires are a masking of power relations, especially between employers and young employees in precarious labor market positions and those with limited digital knowledge or financial means. Further, the positioning of social media as part of a private sphere of life means the invasion of not only employees’, but also managers’ private time and persona. The result of this study hence calls for the need to understand relational work on social media as part of normative managerial work.

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  • 168.
    Liu, G.
    et al.
    Institute of the Building Environment & Sustainability Technology, School of Human Settlements and Civil Engineering, Xi'an Jiaotong University, Xi'an, 710049, China.
    Xiao, T.
    State Key Laboratory for Strength and Vibration of Mechanical Structures, School of Aerospace, Xi'an Jiaotong University, Xi'an, 710049, China.
    Wang, X.
    Institute of the Building Environment & Sustainability Technology, School of Human Settlements and Civil Engineering, Xi'an Jiaotong University, Xi'an, 710049, China.
    Yang, X.
    Institute of the Building Environment & Sustainability Technology, School of Human Settlements and Civil Engineering, Xi'an Jiaotong University, Xi'an, 710049, China.
    Li, Hailong
    Mälardalen University, School of Business, Society and Engineering, Future Energy Center.
    Numerical analysis of inner heating tube position for improving solid-phase transition in a shell-and-tube heat accumulator2023In: Alexandria Engineering Journal, ISSN 1110-0168, E-ISSN 2090-2670, Vol. 65, p. 771-784Article in journal (Refereed)
    Abstract [en]

    Latent heat thermal storage (LHTS) system is vital to reduce environment pollution. In the shell-and-tube heat accumulator, the position of the inner heating tube plays a vital role in the thermal storage. To analyze the effect of the inner tube position on the phase transition, a two-dimensional numerical model is developed. The structure has the minimum full melting time of 3480 s when the inner tube is 12 mm (L = 12 mm) from the center. Compared with L = 0 mm, the full melting time at L = 12 mm can be reduced by 13.4%. 

  • 169.
    Liu, G.
    et al.
    Institute of the Building Environment & Sustainability Technology, School of Human Settlements and Civil Engineering, Xi'an Jiaotong University, Xi'an, China.
    Xiao, T.
    State Key Laboratory for Strength and Vibration of Mechanical Structures, School of Aerospace, Xi'an Jiaotong University, Xi'an, China.
    Wei, P.
    China Northwest Architecture Design and Research Institute, Co. Ltd., Xi'an, China.
    Meng, X.
    Institute of the Building Environment & Sustainability Technology, School of Human Settlements and Civil Engineering, Xi'an Jiaotong University, Xi'an, China.
    Yang, X.
    Institute of the Building Environment & Sustainability Technology, School of Human Settlements and Civil Engineering, Xi'an Jiaotong University, Xi'an, China; Key Laboratory of Thermo-Fluid Science and Engineering of Ministry of Education, School of Energy and Power Engineering, Xi'an Jiaotong University, Shaanxi, Xi'an, China.
    Yan, Jinyue
    Mälardalen University, School of Business, Society and Engineering, Future Energy Center.
    He, Y. -L
    Key Laboratory of Thermo-Fluid Science and Engineering of Ministry of Education, School of Energy and Power Engineering, Xi'an Jiaotong University, Shaanxi, Xi'an, China.
    Experimental and numerical studies on melting/solidification of PCM in a horizontal tank filled with graded metal foam2023In: Solar Energy Materials and Solar Cells, ISSN 0927-0248, E-ISSN 1879-3398, Vol. 250, article id 112092Article in journal (Refereed)
    Abstract [en]

    Although solar energy is a clean and abundant resource, it has an unstable nature. It is demonstrated that latent thermal energy storage (LTES) systems have been an excellent way to utilize solar energy fully and widely. However, LTES has the problem of insufficient thermal conductivity. For this reason, it is inevitable to consider effective methods to intensify the thermal conductivity of LTES system. In the current study, experiment and numerical simulation are used to study the influence of non-uniform metal foams on heat transfer during phase transition. In this study, a horizontal shell-and-tube LTES test system is established. Moreover, the phase change melting rate of radially filled metal foams with different porosity gradients is compared. According to the numerical simulation results of phase interface, velocity field and temperature field, natural convection can accelerate the melting of PCM. However, there is no distinct effect on the solidification process. When the equivalent porosity is 0.94, the optimal combination (melting process is 0.84-0.92-0.99 and solidification process is 0.87-0.94-0.97), compared with the uniform structure, can shorten the total consumption time by 9.7% and 6.2%, respectively. 

  • 170.
    Liu, J.
    et al.
    School of Economics and Management, China University of Petroleum, Beijing, Changping, Beijing, 102249, China.
    Zhang, Q.
    School of Economics and Management, China University of Petroleum, Beijing, Changping, Beijing, 102249, China.
    Li, Hailong
    Mälardalen University, School of Business, Society and Engineering, Future Energy Center.
    Chen, S.
    School of Management and Economics, Beijing Institute of Technology, Haidian, Beijing, 100081, China.
    Teng, F.
    School of Economics and Management, China University of Petroleum, Beijing, Changping, Beijing, 102249, China.
    Investment decision on carbon capture and utilization (CCU) technologies: A real option model based on technology learning effect2022In: Applied Energy, ISSN 0306-2619, E-ISSN 1872-9118, Vol. 322, article id 119514Article in journal (Refereed)
    Abstract [en]

    Carbon Capture and Utilization (CCU) technologies are crucial to achieving carbon neutrality targets. However, assessing the investment value and timing comprehensively is still challenging for CCU due to uncertainties in technologies and markets from a long-term perspective. In order to assist decision making, this work develops a new real option investment decision model based on the technology learning effect. In particular, the component-based two-factor technology learning curve approach is proposed to predict the future costs for each component. To verify this model, it is used to analyze two CCU processes, including the enhanced oil recovery using CO2 (CO2-EOR) and methanol synthesis from captured CO2 (CO2-MET). Results show that the proposed model can effectively predict the technology cost curve and find the optimal investment decision for the two applications considering various uncertainties. It is also found that the oil price at least needs to be over 80 $/barrel for CO2-EOR and the methanol price needs to be over 580 $/ton for CO2-MET respectively to trigger immediate investment. Comparatively, investing in CO2-MET projects is more economical than in CO2-EOR projects. 

  • 171.
    Liu, Junwei
    et al.
    Tianjin Univ, Collaborat Innovat Ctr Chem Sci & Engn Tianjin, Sch Environm Sci & Engn, Sch Mat Sci & Engn,Tianjin Key Lab Mol Optoelect S, Tianjin 300350, Peoples R China.;Shandong Univ, Sch Phys, Jinan 250100, Peoples R China.;Shandong Univ, State Key Lab Crystal Mat, Jinan 250100, Peoples R China.;Hubei Longzhong Lab, Xiangyang 441000, Peoples R China.;Hong Kong Polytech Univ, Dept Bldg Environm & Energy Engn, Hong Kong, Peoples R China..
    Zhou, Zhihua
    Tianjin Univ, Collaborat Innovat Ctr Chem Sci & Engn Tianjin, Sch Environm Sci & Engn, Sch Mat Sci & Engn,Tianjin Key Lab Mol Optoelect S, Tianjin 300350, Peoples R China.;Shandong Univ, State Key Lab Crystal Mat, Jinan 250100, Peoples R China..
    Gao, Yuping
    Nankai Univ, Ctr Nanoscale Sci & Technol, Tianjin 300071, Peoples R China.;Inst Polymer Chem, Coll Chem, Key Lab Funct Polymer Mat, Tianjin 300071, Peoples R China.;Nankai Univ, Renewable Energy Convers & Storage Ctr RECAST, Tianjin 300071, Peoples R China..
    Wu, Yin
    Shaanxi Normal Univ, Sch Mat Sci & Engn, Key Lab Appl Surface & Colloid Chem, Minist Educ,Shaanxi Key Lab Adv Energy Devices,Sha, Xian 710119, Peoples R China..
    Wang, Jingjing
    Tianjin Univ, Collaborat Innovat Ctr Chem Sci & Engn Tianjin, Sch Environm Sci & Engn, Sch Mat Sci & Engn,Tianjin Key Lab Mol Optoelect S, Tianjin 300350, Peoples R China.;Shandong Univ, Sch Phys, Jinan 250100, Peoples R China.;Shandong Univ, State Key Lab Crystal Mat, Jinan 250100, Peoples R China.;Hubei Longzhong Lab, Xiangyang 441000, Peoples R China..
    Li, Haojin
    Shaanxi Normal Univ, Sch Mat Sci & Engn, Key Lab Appl Surface & Colloid Chem, Minist Educ,Shaanxi Key Lab Adv Energy Devices,Sha, Xian 710119, Peoples R China..
    Wang, Qian
    Shandong Univ, Sch Phys, Jinan 250100, Peoples R China.;Shandong Univ, State Key Lab Crystal Mat, Jinan 250100, Peoples R China..
    Zhou, Kangkang
    Tianjin Univ, Collaborat Innovat Ctr Chem Sci & Engn Tianjin, Sch Environm Sci & Engn, Sch Mat Sci & Engn,Tianjin Key Lab Mol Optoelect S, Tianjin 300350, Peoples R China..
    Xian, Kaihu
    Tianjin Univ, Collaborat Innovat Ctr Chem Sci & Engn Tianjin, Sch Environm Sci & Engn, Sch Mat Sci & Engn,Tianjin Key Lab Mol Optoelect S, Tianjin 300350, Peoples R China..
    Chen, Yu
    Chinese Acad Sci, Inst High Energy Phys, Beijing 100049, Peoples R China..
    Zhao, Wenchao
    Nanjing Forestry Univ, Coll Mat Sci & Engn, Coinnovat Ctr Efficient Proc & Utilizat Forest Res, Nanjing 210037, Peoples R China..
    Zhang, Fei
    Tianjin Univ, Sch Chem Engn & Technol, Tianjin 300072, Peoples R China..
    Yin, Hang
    Shandong Univ, Sch Phys, Jinan 250100, Peoples R China.;Shandong Univ, State Key Lab Crystal Mat, Jinan 250100, Peoples R China..
    Liu, Yongsheng
    Nankai Univ, Ctr Nanoscale Sci & Technol, Tianjin 300071, Peoples R China.;Inst Polymer Chem, Coll Chem, Key Lab Funct Polymer Mat, Tianjin 300071, Peoples R China.;Nankai Univ, Renewable Energy Convers & Storage Ctr RECAST, Tianjin 300071, Peoples R China..
    Zhao, Kui
    Shaanxi Normal Univ, Sch Mat Sci & Engn, Key Lab Appl Surface & Colloid Chem, Minist Educ,Shaanxi Key Lab Adv Energy Devices,Sha, Xian 710119, Peoples R China..
    Yan, Jinyue
    Mälardalen University, School of Business, Society and Engineering, Future Energy Center. Hong Kong Polytech Univ, Dept Bldg Environm & Energy Engn, Hong Kong, Peoples R China..
    Ye, Long
    Tianjin Univ, Collaborat Innovat Ctr Chem Sci & Engn Tianjin, Sch Environm Sci & Engn, Sch Mat Sci & Engn,Tianjin Key Lab Mol Optoelect S, Tianjin 300350, Peoples R China.;Shandong Univ, Sch Phys, Jinan 250100, Peoples R China.;Shandong Univ, State Key Lab Crystal Mat, Jinan 250100, Peoples R China.;Hubei Longzhong Lab, Xiangyang 441000, Peoples R China..
    Polymer synergy for efficient hole transport in solar cells and photodetectors2023In: Energy & Environmental Science, ISSN 1754-5692, E-ISSN 1754-5706Article in journal (Refereed)
    Abstract [en]

    Hole transport materials (HTMs) have greatly advanced the progress of solution-based electronic devices in the past few years. Nevertheless, most devices employing dopant-free organic HTMs can only deliver inferior performance. In this work, we introduced a novel "polymer synergy" strategy to develop versatile dopant-free polymer HTMs for quantum dot/perovskite solar cells and photodetectors. With this synergy strategy, the optical, electrical and aggregation properties of polymer HTMs can be modulated, resulting in complementary absorption, high hole mobility, favorable energy landscape and moderate aggregation. Moreover, a clear orientational transition was observed for the developed HTMs with a 9-fold increase in the face-on/edge-on ratio, providing a highway-like carrier transport for electronic devices, as revealed by in situ characterization and ultrafast transient absorption. With these benefits, the photovoltaic and photodetection performance of quantum dot devices were boosted from 11.8% to 13.5% and from 2.95 x 10(12) to 3.41 x 10(13) Jones (over a 10-fold increase), respectively. Furthermore, the developed polymer HTMs can also significantly enhance the photovoltaic and photodetection performance of perovskite devices from 15.1% to 22.7% and from 2.7 x 10(12) to 2.17 x 10(13)Jones with the same device structure, indicating their great application potential in the emerging optoelectronics.

  • 172.
    Liu, L.
    et al.
    Institute of Thermal Science and Technology, Shandong University, Jinan, 250061, China.
    Bai, F.
    School of Information Technology and Electrical Engineering, University of Queensland, Brisbane, 4072, QLD, Australia.
    Su, C.
    Institute of Thermal Science and Technology, Shandong University, Jinan, 250061, China.
    Ma, C.
    Institute of Thermal Science and Technology, Shandong University, Jinan, 250061, China.
    Yan, R.
    School of Information Technology and Electrical Engineering, University of Queensland, Brisbane, 4072, QLD, Australia.
    Li, Hailong
    Mälardalen University, School of Business, Society and Engineering, Future Energy Center. Institute for Advanced Science and Technology, Shandong University, Jinan, 250061, China.
    Sun, Q.
    Institute of Thermal Science and Technology, Shandong University, Jinan, 250061, China.
    Wennersten, R.
    Institute of Thermal Science and Technology, Shandong University, Jinan, 250061, China.
    Forecasting the occurrence of extreme electricity prices using a multivariate logistic regression model2022In: Energy, ISSN 0360-5442, E-ISSN 1873-6785, Vol. 247, article id 123417Article in journal (Refereed)
    Abstract [en]

    Extreme electricity prices occur with a higher frequency and a larger magnitude in recent years. Accurate forecasting of the occurrence of extreme prices is of great concern to market operators and participants. This paper aims to forecast the occurrence probability of day-ahead extremely low and high electricity prices and investigate the relative importance of different influencing variables. The data obtained from the Australian National Electricity Market (NEM) were employed, including historical prices (one day before and one week before), reserve capacity, load demand, variable renewable energy (VRE) proportion and interconnector flow. A Multivariate Logistic Regression (MLgR) model was proposed, which showed good forecasting capability in terms of model fitness and classification accuracy with different thresholds of extreme prices. In addition, the performance of the MLgR model was verified by comparing with two other models, i.e., Multi-Layer Perceptron (MLP) and Radical Basis Function (RBF) neural network. Relative importance analysis was performed to quantify of the contribution of the variables. The proposed method enriches the theories of electricity price forecast and advances the understanding of the dynamics of extreme prices. By applying the model in practice, it will contribute to promoting the management of operation and establishment of a robust energy market. 

  • 173.
    Liu, Q.
    et al.
    Department of Civil Engineering, McGill University, Montreal, Quebec, H3A 0C3, Canada. Department of Traffic Engineering, Shanghai Jiao Tong University, Shanghai, 200240, China.
    Shi, Xiaodan
    Mälardalen University, School of Business, Society and Engineering, Future Energy Center. Center for Spatial Information Science, The University of Tokyo, Kashiwa, Japan.
    Jiang, R.
    Center for Spatial Information Science, The University of Tokyo, Kashiwa, Japan. Information Technology Center, The University of Tokyo, Kashiwa, Japan.
    Zhang, H.
    School of Urban Planning and Design, Peking University, Shenzhen, Guangdong, 518055, China.
    Lu, L.
    Department of Traffic Engineering, Shanghai Jiao Tong University, Shanghai, 200240, China.
    Shibasaki, R.
    Center for Spatial Information Science, The University of Tokyo, Kashiwa, Japan.
    Modeling interpretable social interactions for pedestrian trajectory2024In: Transportation Research Part C: Emerging Technologies, ISSN 0968-090X, E-ISSN 1879-2359, Vol. 162, article id 104617Article in journal (Refereed)
    Abstract [en]

    The abilities to understand pedestrian social interaction behaviors and to predict their future trajectories are critical for road safety, traffic management and more broadly autonomous vehicles and robots. Social interactions are intuitively heterogeneous and dynamic over time and circumstances, making them hard to explain. In this paper, we creatively investigate modeling interpretable social interactions for pedestrian trajectory, which is not considered by the existing trajectory prediction research. Moreover, we propose a two-stage methodology for interaction modeling - “mode extraction” and “mode aggregation”, and develop a long short-term memory (LSTM)-based model for long-term trajectory prediction, which naturally takes into account multi-types of social interactions. Different from previous models that do not explain how pedestrians interact socially, we extract latent modes that represent social interaction types which scales to an arbitrary number of neighbors. Extensive experiments over two public datasets have been conducted. The quantitative and qualitative results demonstrate that our method is able to capture the multi-modality of human motion and achieve better performance under specific conditions. Its performance is also verified by the interpretation of predicted modes, of which the results are in accordance with common sense. Besides, we have performed sensitivity analysis on the crucial hyperparameters in our model. Code is available at: https://github.com/xiaoluban/Modeling-Interpretable-Social-Interactions-for-Pedestrian-Trajectory.

  • 174.
    Liu, S.
    et al.
    Tianjin Key Lab of Refrigeration Technology, Tianjin University of Commerce, Tianjin, China.
    Hu, C.
    Tianjin Key Lab of Refrigeration Technology, Tianjin University of Commerce, Tianjin, China.
    Dong, Beibei
    Mälardalen University, School of Business, Society and Engineering, Future Energy Center.
    Improvement of control strategy of CO2 capture from biomass CHP plant by chemical absorption2022In: Clean Coal Technology, ISSN 1006-6772, Vol. 28, no 9, p. 112-121Article in journal (Refereed)
    Abstract [en]

    When capturing CO2 from biomass fired combined heat and power (CHP) plants, the changes in the feedstock and the heat and electricity demands affect the performance of chemical absorption CO2 capture system. To handle such impact, this paper proposed an improved reboiler duty control strategy (control strategy B) based on the evaluation of the control performance of the traditional feedback control strategy (control strategy A) to achieve a constant capture rate. Control strategy B is based on control strategy A, and introduces feedforward compensation based on rich solution flow rate to form a feedforward plus feedback control strategy. This work aimed to find a control strategy suitable for chemical absorption CO2 capture from biomass CHP, by comparing the control performance, capture system performance and flexible operation performance of both control strategies. Based on the dynamic simulations of CO2 capture from actual biomass fired CHP plant, it is found that compared with the control strategy A, the feedforward compensation of the control strategy B can reduce the response time of the reboiler duty to external disturbances, and improve the timeliness and accuracy of the regulation of reboiler duty. The settling time of capture rate is reduced by 54 mins with the control strategy B. Facing the flexible change of capture rate setpoint, the time required for the stabilization of capture rate is reduced by 57.9% with control strategy B. Under the continuous external disturbance, the capture rate is maintained at ±3% of the setpoint with control strategy B. At the same time, the energy penalty is reduced by 0.14%, and the total captured CO2 is increased by 0.35%. In addition, the results of dynamic simulation and traditional steady-state simulation show that the dynamic simulation can reflect the impact of external disturbances on the capture system more accurately, and provide a reference for the integration and optimization of related processes.

  • 175.
    Liu, Shengchun
    et al.
    Tianjin Univ Commerce, Tianjin Key Lab Refrigerat Technol, Tianjin, Peoples R China.;UNiLAB Integrated Syst Anal Tools, Singapore, Singapore..
    Wang, Jiahao
    Tianjin Univ Commerce, Tianjin Key Lab Refrigerat Technol, Tianjin, Peoples R China..
    Dai, Baomin
    Tianjin Univ Commerce, Tianjin Key Lab Refrigerat Technol, Tianjin, Peoples R China..
    Yang, Xin
    Tianjin Univ Commerce, Tianjin Key Lab Refrigerat Technol, Tianjin, Peoples R China..
    Nian, Victor
    Tianjin Univ Commerce, Tianjin Key Lab Refrigerat Technol, Tianjin, Peoples R China.;UNiLAB Integrated Syst Anal Tools, Singapore, Singapore.;Natl Univ Singapore, Energy Studies Inst, Singapore, Singapore..
    Li, Hailong
    Mälardalen University, School of Business, Society and Engineering, Future Energy Center. UNiLAB Integrated Syst Anal Tools, Singapore, Singapore.
    Yuan, Jun
    UNiLAB Integrated Syst Anal Tools, Singapore, Singapore.;Shanghai Maritime Univ, China Inst FTZ Supply Chain, Shanghai, Peoples R China..
    Alternative positions of internal heat exchanger for CO2 booster refrigeration system: Thermodynamic analysis and annual thermal performance evaluation2021In: International journal of refrigeration, ISSN 0140-7007, E-ISSN 1879-2081, Vol. 131, p. 1016-1028Article in journal (Refereed)
    Abstract [en]

    Refrigeration systems running on transcritical CO2 cycle are considered an alternative to phase-down the use of hydrofluorocarbons (HFCs) in response to the Kigali Amendment. Responding to the need to improve the efficiency of CO2 booster systems and to identify optimum system designs, thermodynamic models of three booster systems are proposed with the use of an internal heat exchanger (IHX). Findings from this study suggest that placing the IHX with a low-temperature fluid side at the suction line of high pressure stage compressor and high-temperature fluid side at the outlet of gas cooler represents the most optimal approach in improving the coefficient of performance (COP) of the booster system. When operating in the transcritical conditions, the COP values can be improved by 6.35% at the IHX thermal effectiveness of 0.8 and by 6.48% at the ratio of medium temperature load to low temperature load of 6. Using IHX can significantly reduce the compressor discharge pressure, which can be reduced by 0.55 MPa at the ambient temperature of 40 degrees C. Furthermore, by adding IHX, the annual performance factor of CO2 system can be improved significantly by 1.68% and the annual total power consumption can be decreased by 6.48% in the tropical climate. It can be concluded that IHX can improve the COP values of a booster system when operating in the subtropical and tropical regions. 

  • 176.
    Liu, Z.
    et al.
    Institute of Building Environment and Sustainability Technology, School of Human Settlements and Civil Engineering, Xi'an Jiaotong University, Xi'an, 710049, China.
    Chen, Y.
    Ningbo Institute of Digital Twin, Eastern Institute of Technology, Ningbo, 315200, China.
    Yang, X.
    Institute of Building Environment and Sustainability Technology, School of Human Settlements and Civil Engineering, Xi'an Jiaotong University, Xi'an, 710049, China.
    Yan, Jinyue
    Mälardalen University, School of Business, Society and Engineering, Future Energy Center. Department of Building Environment and Energy Engineering, Hong Kong Polytechnic University, Hong Kong, China.
    Power to heat: Opportunity of flexibility services provided by building energy systems2023In: Advances in Applied Energy, ISSN 2666-7924, Vol. 11, article id 100149Article in journal (Refereed)
    Abstract [en]

    Buildings play a crucial role in global electricity consumption, but their function is evolving. Rather than merely consuming energy, buildings have the potential to become energy producers through participating in flexibility services, which involve demand response and distributed energy supplies. However, the new technological and societal challenges that arise from temporal and spatial changes on both supply and demand sides make building services increasingly complex. This paper presents an opportunity for flexibility services offered by building energy systems via power-to-heat technology and discusses four key aspects: quantitative indicators based on thermal inertia, model predictive control for building flexibility, flexible system optimization for smart buildings, and applications of flexible services. Thermal inertia is a crucial factor that transcends technical constraints and serves as a bridge between the demand and supply sides. Demand-side response and data-driven cogeneration under model predictive control are essential for managing building flexibility. In addition, flexible system optimization is achieved through the combination of demand-side trading and disturbed system optimization. Applications of flexible services represent a combination of demand-side trading and disturbed system optimization in the fields of engineering and sociology. Finally, the paper explores the challenges, as well as the potential and models of building flexibility services technologies, including features that can facilitate automated operational decision-making on both the demand and supply sides. 

  • 177.
    Liu, Z.
    et al.
    Eastern Institute for Advanced Study, Eastern Institute of Technology, Zhejiang, Ningbo, 315200, China.
    Du, Y.
    Eastern Institute for Advanced Study, Eastern Institute of Technology, Zhejiang, Ningbo, 315200, China.
    Song, C.
    Higher Information Industry Technology Research Institute, Beijing Information Science and Technology University, Beijing, 100192, China.
    Yang, X.
    Institute of Building Environment and Sustainability Technology, School of Human Settlements and Civil Engineering, Xi'an Jiaotong University, Xi'an, 710049, China .
    Yan, Jinyue
    Mälardalen University, School of Business, Society and Engineering, Future Energy Center.
    Effect of soil moisture content on thermal performance of ground source heat exchangers: An electromagnetism topology-based analysis2023In: Energy Reports, E-ISSN 2352-4847, Vol. 10, p. 3914-3928Article in journal (Refereed)
    Abstract [en]

    Ground source heat pump (GSHP) technology has gained significant attention as a viable solution for the heating, ventilation, and air conditioning (HVAC) of buildings. One of the factors that can impact the performance of GSHP systems is the soil moisture content. In this study, an innovative approach, referred to as soil impedance topology, is introduced as an alternative to traditional methods for measuring soil moisture content in geothermal heat pump systems. This method is inspired by pipeline grid utilizes impedance measurement, which provides a direct measurement of soil moisture content without the need for sensors. The study also proposes a changing rule of impedance with varying moisture content, where capacitance increases and resistance decreases when the soil moisture content is less than 20% but stabilizes beyond a water content of 20%. The accuracy of the topological mechanism prediction method is high, as demonstrated through the verification of the Smith circle and measured data. However, it is noted that the performance may be insufficient in the high frequency band and high soil moisture content. The use of impedance topology provides a more accurate and reliable method for measuring soil moisture content as well as for modeling and predicting heat transfer rates and system performance. This technology has strong potential to improve efficiency, reduce energy costs, and enhance the environmental sustainability of geothermal heat pump systems. 

  • 178.
    Liu, Z.
    et al.
    Qingdao University of Science and Technology, Qingdao, 266061, China.
    Guo, J.
    School of Human Settlements and Civil Engineering, Xi'an Jiaotong University, Xi'an, 710049, China.
    Wang, F.
    China Northwest Architecture Design and Research Institute, CO. Ltd, Shaanxi Province, Xi'an 710077, China.
    Yang, X.
    Yan, Jinyue
    Mälardalen University, School of Business, Society and Engineering, Future Energy Center.
    Innovative ladder-shaped fin design on a latent heat storage device for waste heat recovery2022In: Applied Energy, ISSN 0306-2619, E-ISSN 1872-9118, Vol. 321, article id 119300Article in journal (Refereed)
    Abstract [en]

    Latent heat energy storage system provides an alternative solution to solving the imbalance problem of energy supply and demand. To improve the phase change efficiency, a novel ladder-shaped fin is proposed to accelerate melting process. Under the same mass of fin materials, two groups of fin shapes (totally eight cases) are innovatively designed. Upon being verified by experiments in literature, numerical models account for comprehensive descriptions on melting front propagation with emphasizing temperature development and free convection in the liquid phase. Results demonstrate that the ladder-shaped fins can better optimize the melting channel of phase change material than the straight fin. Compared to the original straight fin case, a maximal 52.2% of the total melting time can be saved. The angle change of fins has a significant effect on reducing the melting time of the whole PCM. In Group I where fins are arranged vertically and horizontally, the total melting time is much shorter than that of each corresponding case in Group II (45° from the vertical axis). For the original straight fin in Group II, a 36.8% reduction in total melting time is obtained if turning fins by 45°clockwise. To be conclusive, it is more beneficial to add fins to mobile heat accumulators than to have no fins, saving more energy charging time. 

  • 179.
    Liu, Z
    et al.
    College of Electromechanical Engineering, Qingdao University of Science and Technology, Qingdao, China.
    Liu, Z.
    College of Electromechanical Engineering, Qingdao University of Science and Technology, Qingdao, China; Institute of Building Environment and Sustainability Technology, School of Human Settlements and Civil Engineering, Xi'an Jiaotong University, Xi'an, China.
    Liu, G.
    Institute of Building Environment and Sustainability Technology, School of Human Settlements and Civil Engineering, Xi'an Jiaotong University, Xi'an, China.
    Yang, Xiaohu
    Mälardalen University, School of Business, Society and Engineering, Future Energy Center. Institute of Building Environment and Sustainability Technology, School of Human Settlements and Civil Engineering, Xi'an Jiaotong University, Xi'an, China.
    Yan, Jinyue
    Mälardalen University, School of Business, Society and Engineering, Future Energy Center.
    Melting assessment on the effect of nonuniform Y-shaped fin upon solid–liquid phase change in a thermal storage tank2022In: Applied Energy, ISSN 0306-2619, E-ISSN 1872-9118, Vol. 321, article id 119330Article in journal (Refereed)
    Abstract [en]

    This study provides an alternative solution to the improvement on solid–liquid phase change by designing a Y-shaped fin in a nonuniform pattern along the gravity direction. A numerical model is established and validated through the present measurement and data in literature. Six cases with different Y-shaped fins and locations are designed and compared to the original straight fin case. Thermal assessments on the melting fraction, temperature field, velocity distribution, and uniformity for melting are made. Results demonstrate that the nonuniform melting features caused by the local natural convection are significantly eliminated by the novel nonuniform fin structure. The time required for melting the lower PCM is found to occupy more than 50% of the completely melting time. The accurate local heat transfer enhancement measures (bottom enhancement) are conducive to markedly reduce the full melting time by 21.5%, compared to the uniform fin pattern. Upon using finned thermal storage tank for a mobilized thermal storage truck (bare tube tank), the initial investment increases by 44.9% but the profit increases by 393.6% and the payback period reduces by 69.2%. The use of fin tube in heat storage tank can quickly obtain higher returns based on a small increase in initial investment. This work provides new insights into the understandings of the transient phase change process and the strategies for guiding the design for thermal energy storage tank. 

  • 180.
    Liu, Z.
    et al.
    Key Lab of Agricultural Water and Soil Engineering of Education Ministry, Northwest A&F University, Yangling, 712100, China.
    Wang, W.
    Key Lab of Agricultural Water and Soil Engineering of Education Ministry, Northwest A&F University, Yangling, 712100, China.
    Chen, Y.
    Eastern Institute for Advanced Study, Yongriver Institute of Technology, Ningbo, 518055, China.
    Wang, L.
    College of Chemical Engineering, Qingdao University of Science and Technology, Qingdao, 266042, China.
    Guo, Z.
    Center for Spatial Information Science, University of Tokyo, Kashiwa, 277-8568, Japan.
    Yang, Xiaohu
    Mälardalen University, School of Business, Society and Engineering, Future Energy Center. Institute of the Building Environment & Sustainability Technology, School of Human Settlements and Civil Engineering, Xi'an Jiaotong University, Xi'an, 710049, China.
    Yan, Jinyue
    Mälardalen University, School of Business, Society and Engineering, Future Energy Center. Department of Building Environment and Energy Engineering, Hong Kong Polytechnic University, Hong Kong.
    Solar harvest: Enhancing carbon sequestration and energy efficiency in solar greenhouses with PVT and GSHP systems2023In: Renewable energy, ISSN 0960-1481, E-ISSN 1879-0682, Vol. 211, p. 112-125Article in journal (Refereed)
    Abstract [en]

    It is universally acknowledged that climate change brings widespread attention to solar greenhouse plant carbon sequestration. Suitable technologies in solar greenhouses were, are, and will be play a leading role in this vital transition. The primary aim of this research is to examine the energy efficiency and carbon sequestration potential of a solar-assisted ground-source heat pump (SAGSHP) heating system. This hybrid system, which integrates a horizontal ground-source heat pump (GSHP) system with PVT and heat storage, can efficiently fulfill the heating demands of a greenhouse and function as a positive energy building. Four plants include cucumber, tomato, cowpea, and lettuce were selected to compare the carbon absorption effects. Results show that the hybrid system outperforms conventional systems, with a coefficient of performance (COP) of 6.71 during peak hours and PVT efficiency over 57.88%, which effectively meet the heat load of the greenhouse and keep the indoor heat comfortable. In addition, for the carbon sequestration potential of four plants, tomato exhibited the highest photosynthetic carbon sequestration of 3522 kgCO2·m−2. Cowpea showed the strongest daily carbon sequestration capacity at 26.86 gCO2m−2d−1 and better economic income. Through the application of this enhanced solar greenhouse, people can enhance the utilization of solar energy, establish flexible interaction between energy and information flow, and make a promising option for sustainable building design. 

  • 181.
    Liu, Z.
    et al.
    Department of Energy and Electrical Engineering, Northwest A&F University, Shaanxi, Yangling, China; Institute of Building Environment and Sustainability Technology, School of Human Settlements and Civil Engineering, Xi'an Jiaotong University, Xi'an, China.
    Yang, X.
    Institute of Building Environment and Sustainability Technology, School of Human Settlements and Civil Engineering, Xi'an Jiaotong University, Xi'an, China.
    Ali, H. M.
    Mechanical Engineering Department, King Fahd University of Petroleum & Minerals (KFUPM), Dhahran, Saudi Arabia.
    Liu, R.
    Institute of Scientific and Industrial Research, Osaka University, Mihogaoka 8-1, Osaka, Ibaraki, Japan.
    Yan, Jinyue
    Mälardalen University, School of Business, Society and Engineering, Future Energy Center.
    Multi-objective optimizations and multi-criteria assessments for a nanofluid-aided geothermal PV hybrid system2023In: Energy Reports, E-ISSN 2352-4847, Vol. 9, p. 96-113Article in journal (Refereed)
    Abstract [en]

    Energy transition has brought widespread attentions to the concept of coupled utilization of the geothermal and solar energy. This paper provides an integrated assessment on developing a nanofluid geothermal-photovoltaic hybrid system that addresses the multi-objective optimization and multi-criteria evaluation difficulties. The coupling system design and dispatch are optimized by considering the multiple objectives from the microscopic particles to the system. The life cycle cost, levelized cost of energy, levelized cost of heat, and the irreversibility are introduced in the optimization stage. The optimization parameters include the pipe arrangement, type of nanoparticles, and the concentration of the nanoparticles in nanofluids. A combined analysis including the energy, exergy, economy, and the environment is proposed to evaluate the various objectives and cases. The results show that the combination of 2% Al2O3 nanofluid and spiral pipe has the optimum performance. The monocrystalline solar panels with the nanofluids-aided heat pump create the least CO2 emissions (550 kg/year), the least LCOE (198.18 $), and the highest exergy efficiency. However, the LCOH (211.78 $/MWh) is still much high. Only when the electricity cost is higher than 0.11$/kWh, the proposed coupling system would show competitiveness. In summary, these results effectively prove the robustness and superiority of the hybrid system. 

  • 182.
    Lu, L.
    et al.
    School of Human Settlements and Civil Engineering, Xi'an Jiaotong University, Xi'an, China.
    Xiao, T.
    State Key Laboratory for Strength and Vibration of Mechanical Structures, School of Aerospace, Xi'an Jiaotong University, Xi'an, China.
    Yang, X.
    School of Human Settlements and Civil Engineering, Xi'an Jiaotong University, Xi'an, China.
    Zhou, X.
    School of Human Settlements and Civil Engineering, Xi'an Jiaotong University, Xi'an, China.
    Yan, Jinyue
    Mälardalen University, School of Business, Society and Engineering, Future Energy Center.
    Refinement and predicting formaldehyde concentrations of indoor fabric: Effects of temperature and humidity2023In: Chemosphere, ISSN 0045-6535, E-ISSN 1879-1298, Vol. 342, article id 140096Article in journal (Refereed)
    Abstract [en]

    Indoor air pollution resulting from volatile organic compounds (VOCs) is a significant health concern, especially formaldehyde. Therefore, predicting indoor formaldehyde concentration is essential for environmental control. In this research, the authors develop a thermal and wet coupling calculation model of porous fabric that considers the influence of different phases of wet components and the coupling effect of heat and humidity on formaldehyde migration. We propose a modified calculation method of the formaldehyde mass transfer characteristic parameters of fabric to obtain the diffusion coefficient D and partition coefficient K. The heat and humidity coupling model and formaldehyde mass transfer model of fabric are simultaneously solved, and the authors analyze the influence mechanism of fabric loading rate, fabric type, temperature, and humidity on indoor formaldehyde mass transfer characteristics. We study the variation trend of fabric formaldehyde mass transfer characteristics coefficient and the temporal and spatial distribution of indoor formaldehyde concentration. The theoretical model is applied to practical problems by pre-evaluating the indoor formaldehyde concentration of decorated residential buildings in typical climate areas of China before occupancy. The authors obtain the variation rule of indoor formaldehyde concentration of residential buildings under typical hot and humid climate conditions, building materials, furniture, and fabrics. To provide theoretical support for indoor environmental control and human health protection.

  • 183.
    Lu, Liu
    et al.
    Xi An Jiao Tong Univ, Sch Human Settlements & Civil Engn, Xian, Peoples R China..
    Huang, Xinyu
    Xi An Jiao Tong Univ, Sch Human Settlements & Civil Engn, Xian, Peoples R China..
    Zhou, Xiaojun
    Xi An Jiao Tong Univ, Sch Human Settlements & Civil Engn, Xian, Peoples R China..
    Guo, Junfei
    Xi An Jiao Tong Univ, Sch Human Settlements & Civil Engn, Xian, Peoples R China..
    Yang, Xiaohu
    Xi An Jiao Tong Univ, Sch Human Settlements & Civil Engn, Xian, Peoples R China..
    Yan, Jinyue
    Mälardalen University, School of Business, Society and Engineering, Future Energy Center. Hong Kong Polytech Univ, Dept Bldg Environm & Energy Engn, Kowloon, Hong Kong, Peoples R China..
    High-performance formaldehyde prediction for indoor air quality assessment using time series deep learning2024In: Building Simulation, ISSN 1996-3599, E-ISSN 1996-8744Article in journal (Refereed)
    Abstract [en]

    Indoor air pollution resulting from volatile organic compounds (VOCs), especially formaldehyde, is a significant health concern needed to predict indoor formaldehyde concentration (Cf) in green intelligent building design. This study develops a thermal and wet coupling calculation model of porous fabric to account for the migration of formaldehyde molecules in indoor air and cotton, silk, and polyester fabric with heat flux in Harbin, Beijing, Xi'an, Shanghai, Guangzhou, and Kunming, China. The time-by-time indoor dry-bulb temperature (T), relative humidity (RH), and Cf, obtained from verified simulations, were collated and used as input data for the long short-term memory (LSTM) of the deep learning model that predicts indoor multivariate time series Cf from the secondary source effects of indoor fabrics (adsorption and release of formaldehyde). The trained LSTM model can be used to predict multivariate time series Cf at other emission times and locations. The LSTM-based model also predicted Cf with mean absolute percentage error (MAPE), symmetric mean absolute percentage error (SMAPE), mean absolute error (MAE), mean square error (MSE), and root mean square error (RMSE) that fell within 10%, 10%, 0.5, 0.5, and 0.8, respectively. In addition, the characteristics of the input dataset, model parameters, the prediction accuracy of different indoor fabrics, and the uncertainty of the data set are analyzed. The results show that the prediction accuracy of single data set input is higher than that of temperature and humidity input, and the prediction accuracy of LSTM is better than recurrent neural network (RNN). The method's feasibility was established, and the study provides theoretical support for guiding indoor air pollution control measures and ensuring human health and safety.

  • 184.
    Lu, Silvia Ma
    et al.
    Mälardalen University, School of Business, Society and Engineering, Future Energy Center.
    Yang, D.
    School of Electrical Engineering and Automation, Harbin Institute of Technology 2 , Harbin, Heilongjiang, China.
    Anderson, M. C.
    USDA ARS, Hydrology and Remote Sensing Laboratory 3 , Beltsville, Maryland 20705, USA.
    Zainali, Sebastian
    Mälardalen University, School of Business, Society and Engineering, Future Energy Center.
    Stridh, Bengt
    Mälardalen University, School of Business, Society and Engineering, Future Energy Center.
    Avelin, Anders
    Mälardalen University, School of Business, Society and Engineering, Future Energy Center.
    Campana, Pietro Elia
    Mälardalen University, School of Business, Society and Engineering, Future Energy Center.
    Photosynthetically active radiation separation model for high-latitude regions in agrivoltaic systems modeling2024In: Journal of Renewable and Sustainable Energy, E-ISSN 1941-7012, Vol. 16, no 1, article id 013503Article in journal (Refereed)
    Abstract [en]

    Photosynthetically active radiation is a key parameter for determining crop yield. Separating photosynthetically active radiation into direct and diffuse components is significant to agrivoltaic systems. The varying shading conditions caused by the solar panels produce a higher contribution of diffuse irradiance reaching the crops. This study introduces a new separation model capable of accurately estimating the diffuse component from the global photosynthetically active radiation and conveniently retrievable meteorological parameters. The model modifies one of the highest-performing separation models for broadband irradiance, namely, the Yang2 model. Four new predictors are added: atmospheric optical thickness, vapor pressure deficit, aerosol optical depth, and surface albedo. The proposed model has been calibrated, tested, and validated at three sites in Sweden with latitudes above 58 °N, outperforming four other models in all examined locations, with R2 values greater than 0.90. The applicability of the developed model is demonstrated using data retrieved from Sweden's first agrivoltaic system. A variety of data availability cases representative of current and future agrivoltaic systems is tested. If on-site measurements of diffuse photosynthetically active radiation are not available, the model calibrated based on nearby stations can be a suitable first approximation, obtaining an R2 of 0.89. Utilizing predictor values derived from satellite data is an alternative method, but the spatial resolution must be considered cautiously as the R2 dropped to 0.73.

  • 185.
    Luo, H.
    et al.
    Institute of the Building Environment & Sustainability Technology, School of Human Settlements and Civil Engineering, Xi'an Jiaotong University, Xi'an, 710049, China.
    Gao, X.
    Institute of the Building Environment & Sustainability Technology, School of Human Settlements and Civil Engineering, Xi'an Jiaotong University, Xi'an, 710049, China.
    Liu, Z.
    Department of Chemical Engineering, School of Engineering, The University of Manchester, Manchester, M13 9PL, United Kingdom.
    Liu, W.
    Institute of the Building Environment & Sustainability Technology, School of Human Settlements and Civil Engineering, Xi'an Jiaotong University, Xi'an, 710049, China.
    Li, Y.
    Institute of the Building Environment & Sustainability Technology, School of Human Settlements and Civil Engineering, Xi'an Jiaotong University, Xi'an, 710049, China.
    Meng, X.
    Institute of the Building Environment & Sustainability Technology, School of Human Settlements and Civil Engineering, Xi'an Jiaotong University, Xi'an, 710049, China.
    Yang, X.
    Institute of the Building Environment & Sustainability Technology, School of Human Settlements and Civil Engineering, Xi'an Jiaotong University, Xi'an, 710049, China.
    Yan, Jinyue
    Mälardalen University, School of Business, Society and Engineering, Future Energy Center. Department of Building Environment and Energy Engineering, The Hong Kong Polytechnic University, Kowloon, Hong Kong.
    Sun, L.
    Institute of the Building Environment & Sustainability Technology, School of Human Settlements and Civil Engineering, Xi'an Jiaotong University, Xi'an, 710049, China.
    Real-time Characterization Model of Carbon Emissions Based on Land-use Status: A Case Study of Xi'an City, China2024In: Journal of Cleaner Production, ISSN 0959-6526, E-ISSN 1879-1786, Vol. 434, article id 140069Article in journal (Refereed)
    Abstract [en]

    The traditional carbon accounting method, with a lag of over 2 years due to the release time of statistical yearbooks, impedes timely policy adjustments in urban planning and management. Hence, there is an urgent need to establish a real-time carbon emissions characterization model. Xi'an which has a complex land-use structure was chosen as the study site and its carbon emissions were calculated using the Emission Factor Method. The GIS-Kernel Density (KD) model was constructed, and land use was subdivided based on Point of Interest (POI) and road network data. Based on the results of carbon emissions accounting and land-use subdivision, a Multilayer perceptron (MLP) model was established. The remote sensing (RS) images of Xi'an underwent supervised classification, and the carbon emissions of Xi'an were characterized based on the subdivision results and MLP model. The results show that: (1) The accuracy of the characterization model is more than 90%, and with the improvement of RS technology, the accuracy will be further improved; (2) Compared with the existing model, this model can real time reflect the spatial distribution of carbon emissions; (3) Atmospheric emission of Xi'an will be 41.92 million tons at the end of 2022, a decrease of 2.80 million tons compared with that of 2020, but an increase of 0.33 million tons from 2021. The north of Xi'an and periphery of the central urban area are the main carbon sink loss areas, while the east of Xi'an and north foot of the Qinling Mountains are carbon sink growth areas.

  • 186.
    Luo, H.
    et al.
    Institute of the Building Environment & Sustainability Technology, School of Human Settlements and Civil Engineering, Xi'an Jiaotong University, Xi'an, 710049, China.
    Li, Y.
    Institute of the Building Environment & Sustainability Technology, School of Human Settlements and Civil Engineering, Xi'an Jiaotong University, Xi'an, 710049, China.
    Gao, X.
    Institute of the Building Environment & Sustainability Technology, School of Human Settlements and Civil Engineering, Xi'an Jiaotong University, Xi'an, 710049, China.
    Meng, X.
    Institute of the Building Environment & Sustainability Technology, School of Human Settlements and Civil Engineering, Xi'an Jiaotong University, Xi'an, 710049, China.
    Yang, X.
    Institute of the Building Environment & Sustainability Technology, School of Human Settlements and Civil Engineering, Xi'an Jiaotong University, Xi'an, 710049, China.
    Yan, Jinyue
    Mälardalen University, School of Business, Society and Engineering, Future Energy Center. Department of Building Environment and Energy Engineering, The Hong Kong Polytechnic University, Kowloon, Hong Kong.
    Carbon emission prediction model of prefecture-level administrative region: A land-use-based case study of Xi'an city, China2023In: Applied Energy, ISSN 0306-2619, E-ISSN 1872-9118, Vol. 348, article id 121488Article in journal (Refereed)
    Abstract [en]

    Climate change has become a global concern, and the prediction of carbon emissions is key to achieving carbon-reduction goals. The existing framework cannot accurately reflect the spatial distribution of carbon emissions, making it difficult to guide urban planning and management. Therefore, in this study, a carbon emission spatial simulation and prediction model was established. The model includes the GIS-Kernel Density sub-model for subdividing built-up area, the Land Use-Carbon Emission sub-model for establishing the correlation between land use and carbon emissions, the Multi Objective Programming-Principal Component Analysis-BP neural network sub-model for presetting development scenarios, and the Patch-generating Land-use Simulation sub-model for predicting. Xi'an was chosen as the study site, and two extreme scenarios were determined. A total of 373,318 development paths were segmented from the interval, and the optimal path was selected. All scenarios were simulated, and the carbon emissions and their spatial distribution were calculated. The results showed that the overall accuracy of the simulation exceeded 90%. Under the optimal path, Xi'an's carbon emissions reach 60.6 million tons at peak time, which will be reduced to 47.38 million tons by 2060. In addition, the model analyzed the temporal and spatial changes of carbon sources and sinks and drew up the path of carbon reduction by technology and urban planning. This model can provide a reference for regional carbon-reduction planning and carbon reduction technology implantation. It can propose strategies from the perspective of planning and management. 

  • 187.
    Luo, Zhengyi
    et al.
    Hunan University, China; Key Laboratory of Building Safety and Energy Efficiency of the Ministry of Education, China.
    Peng, Jinqing
    Hunan University, China; Key Laboratory of Building Safety and Energy Efficiency of the Ministry of Education, China.
    Cao, Jingyu
    Hunan University, China; Key Laboratory of Building Safety and Energy Efficiency of the Ministry of Education, China.
    Yin, Rongxin
    Hunan University, China; Key Laboratory of Building Safety and Energy Efficiency of the Ministry of Education, China.
    Zou, Bin
    Hunan University, China; Key Laboratory of Building Safety and Energy Efficiency of the Ministry of Education, China.
    Tan, Yutong
    Hunan University, China; Key Laboratory of Building Safety and Energy Efficiency of the Ministry of Education, China.
    Yan, Jinyue
    Mälardalen University, School of Business, Society and Engineering, Future Energy Center.
    Demand Flexibility of Residential Buildings: Definitions, Flexible Loads, and Quantification Methods2022In: Engineering, ISSN 2095-8099, Vol. 16, p. 123-140Article in journal (Refereed)
    Abstract [en]

    This paper reviews recent research on the demand flexibility of residential buildings in regard to definitions, flexible loads, and quantification methods. A systematic distinction of the terminology is made, including the demand flexibility, operation flexibility, and energy flexibility of buildings. A comprehensive definition of building demand flexibility is proposed based on an analysis of the existing definitions. Moreover, the flexibility capabilities and operation characteristics of the main residential flexible loads are summarized and compared. Models and evaluation indicators to quantify the flexibility of these flexible loads are reviewed and summarized. Current research gaps and challenges are identified and analyzed as well. The results indicate that previous studies have focused on the flexibility of central air conditioning, electric water heaters, wet appliances, refrigerators, and lighting, where the proportion of studies focusing on each of these subjects is 36.7%, 25.7%, 14.7%, 9.2%, and 8.3%, respectively. These flexible loads are different in running modes, usage frequencies, seasons, and capabilities for shedding, shifting, and modulation, while their response characteristics are not yet clear. Furthermore, recommendations are given for the application of white-, black-, and grey-box models for modeling flexible loads in different situations. Numerous static flexibility evaluation indicators that are based on the aspects of power, temporality, energy, efficiency, economics, and the environment have been proposed in previous publications, but a consensus and standardized evaluation framework is lacking. This review can help readers better understand building demand flexibility and learn about the characteristics of different residential flexible loads, while also providing suggestions for future research on the modeling techniques and evaluation metrics of residential building demand flexibility.

  • 188.
    Ma Lu, Silvia
    Mälardalen University, School of Business, Society and Engineering, Future Energy Center.
    Solar Irradiance Assessment in Agrivoltaic Systems: Understanding Photosynthetically Active Radiation Separation Models and Dynamic Crop Albedo Effect in Agrivoltaic Systems Modelling2024Licentiate thesis, comprehensive summary (Other academic)
    Abstract [en]

    Agrivoltaics, also referred as agrivoltaic systems, present an appealing solution, owing to its dual land use and integrated food-energy system, for the shift to renewable energy. However, it raises concerns about the complex synergies and trade-offs between crop growth and solar photovoltaic panels. Crops grown under open-field traditional agriculture receive uniformly distributed Sun irradiance, whereas agrivoltaics introduces variable shadowing, which interferes with the homogeneity of light collected by crops. 

    Agrivoltaics emphasises the significance of the diffuse irradiance component during shading conditions when direct irradiance is blocked by solar panels. Decomposition models are essential for estimating the diffuse light component from the global one. This thesis conducts a benchmarking investigation of state-of-the-art solar irradiance decomposition models to identify the most suitable ones for decomposing photosynthetically active radiation in specific Swedish sites. The results lead to a novel separation model that outperforms the top models revealed in the benchmarking analysis. Various scenarios common in agrivoltaic sites are used to test the applicability of the model and guide model selection based on available data. 

    In agrivoltaic systems, where solar panels disrupt incoming sunlight to crops, the crop reflectivity or albedo influences solar panels, particularly those with bifacial solar cells. This thesis further investigates how ground-reflected irradiance components affect the front and rear sides of bifacial system designs under varied ground albedo circumstances. Using Agri-OptiCE®, this research examines how albedo data quality affects bifacial systems. The findings contribute to improve the precision of plane-of-array irradiance and power output estimations, hence aiding the practical implementation of agrivoltaic systems across the globe. 

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  • 189.
    Ma Lu, Silvia
    et al.
    Mälardalen University, School of Business, Society and Engineering, Future Energy Center.
    Zainali, Sebastian
    Mälardalen University, School of Business, Society and Engineering, Future Energy Center.
    Stridh, Bengt
    Mälardalen University, School of Business, Society and Engineering, Future Energy Center.
    Avelin, Anders
    Mälardalen University, School of Business, Society and Engineering, Future Energy Center.
    Amaducci, S.
    Univ Cattolica Sacro Cuore, Dept Sustainable Crop Prod, Via Emilia Parmense 84, I-29122 Piacenza, Italy..
    Colauzzi, M.
    Univ Cattolica Sacro Cuore, Dept Sustainable Crop Prod, Via Emilia Parmense 84, I-29122 Piacenza, Italy..
    Campana, Pietro Elia
    Mälardalen University, School of Business, Society and Engineering, Future Energy Center.
    Photosynthetically active radiation decomposition models for agrivoltaic systems applications2022In: Solar Energy, ISSN 0038-092X, E-ISSN 1471-1257, Vol. 244, p. 536-549Article in journal (Refereed)
    Abstract [en]

    Decomposition models of solar irradiance estimate the magnitude of diffuse horizontal irradiance from global horizontal irradiance. These two radiation components are well known to be essential for predicting the performance of solar photovoltaic systems. In open-field agrivoltaic systems (i.e., the dual use of land for both agricultural activities and solar power conversion), cultivated crops receive unequal amounts of direct, diffuse, and reflected photosynthetically active radiation (PAR). These uneven amounts depend on where the crops are growing due to the non-homogenous shadings caused by the presence of the installed solar panels (above the crops or vertically mounted). It is known that, per unit of total PAR, diffuse PAR is more efficient for canopy photosynthesis than is direct PAR. For this reason, it is essential to estimate the diffuse PAR component when agrivoltaic systems are being assessed, in order to properly predict the crop yield. Since PAR is the electro-magnetic radiation in the 400-700 nm waveband that can be used for photosynthesis by the crops, several stand-alone decomposition models typically used to split global horizontal irradiance are selected in this study to decompose PAR into direct and diffuse. These models are applied and validated in three locations in Sweden (Lanna, Hyltemossa and Norunda) using the coefficients stated on the models' original publications and locally fitted coefficients. The results showed weaker performances in all stand-alone models for non-locally fitted coefficients (nRMSE ranging from 27% to 43%). However, performances improve with re-parameterization, with a highest nRMSE of 35.24% in Lanna. The Y(ANG)2 decomposition model is the best-performing one, with the lowest nRMSE of 23.75% in Norunda when applying re-estimated coefficients. Country level sets of coefficients for the best-performing models (Y(ANG)2 and STARKE) are given after parameterization using combined data for all three locations in Sweden. These Sweden-fitted models are tested and show an nRMSE of 25.08% (Y(ANG)2) and 28.60% (STARKE). These results can be used to perform estimations of the PAR diffuse component in Sweden wherever ground measurements are not available. The overall methodology can be similarly applied to other countries.

  • 190.
    Ma Lu, Silvia
    et al.
    Mälardalen University, School of Business, Society and Engineering, Future Energy Center.
    Zainali, Sebastian
    Mälardalen University, School of Business, Society and Engineering, Future Energy Center.
    Sundström, Elin
    Mälardalen University.
    Nygren, Anton
    Mälardalen University.
    Stridh, Bengt
    Mälardalen University, School of Business, Society and Engineering, Future Energy Center.
    Avelin, Anders
    Mälardalen University, School of Business, Society and Engineering, Future Energy Center.
    Campana, Pietro Elia
    Mälardalen University, School of Business, Society and Engineering, Future Energy Center.
    Validation of Vertical Bifacial Agrivoltaic and Other Systems Modelling: Effect of Dynamic Albedo on Irradiance and Power Output Estimations2023Conference paper (Refereed)
    Abstract [en]

    In agrivoltaic systems combining solar photovoltaic and agricultural activities, ground albedo is mainly characterized by the crop and its seasonal variations. This study examines the effects of using fixed, satellite-derived, and hourly measured albedo on the performance of a vertical bifacial system and a 1-axis tracking system using a bifacial photovoltaic model (AgriOptiCE®). The model is developed with Matlab® and partially based on the open-source package pvlib. AgriOptiCE® is firstly validated by comparing estimated front and rear irradiances with on-site measurements for specific periods from a 1-axis tracker site in Golden, USA and a vertical agrivoltaic system in Västerås, Sweden. Furthermore, photovoltaic system power output estimations using AgriOptiCE® are also validated for the vertical agrivoltaic system and the conventional ground-mounted fixed-tilt system at the same location. The validations demonstrate the high accuracy of the proposed model in estimating front and rear irradiances and power output, obtaining R2 > 0.85 for all the studied cases. The study results indicate that measured albedo provides the highest accuracy, while satellite- derived albedo has poorer results due to the broader spatial, temporal, and spectral resolution. Fixed albedo is not recommended for yearly assessment of bifacial PV systems because it cannot account for snow events and daily variations, resulting in lower overall accuracy. 

  • 191.
    Mabecua, Fastudo Jorge
    et al.
    Mälardalen University, School of Business, Society and Engineering, Future Energy Center.
    Dimande, N.
    Eduardo Mondlane University, Department of Physics, Faculty of Sciences, Maputo, Mozambique.
    Condo, A.
    Eduardo Mondlane University, Department of Chemical Engineering, Faculty of Engineering, Maputo, Mozambique.
    Klintenberg, P.
    Blekinge Institute of Technology, Department of Spatial Planning, Karlskrona, Sweden.
    Lucas, C.
    Eduardo Mondlane University, Department of Chemical Engineering, Faculty of Engineering, Maputo, Mozambique.
    Schwede, Sebastian
    Mälardalen University, School of Business, Society and Engineering, Future Energy Center.
    Barriers to successful implementation of small-scale biogas technology in Southern Africa: What can be learned from past initiatives in Mozambique?2024In: Energy Proceedings, Scanditale AB , 2024, Vol. 3Conference paper (Refereed)
    Abstract [en]

    This paper examines common barriers limiting the implementation of small-scale biogas systems in rural Southern Africa through a literature study and a case study of six small-scale biogas digesters installed in Maputo province in Mozambique. The study strives to understand why the implementation rate of small-scale biogas systems in rural Southern Africa is so limited despite favourable conditions. The literature study identified several common barriers to the successful implementation of small-scale biogas in rural Southern Africa related to financial, technical, socio-cultural, and institutional issues. The case study results show that only one digester was operational, and five failed and were abandoned. Low technical ability of constructors results in poor-quality installations. Lack of technological know-how and local capacity for operation and maintenance of digesters are primary reasons for the failure of the digesters. Possible solutions are to intensify research, demonstration, dissemination and application of small-scale biogas; adapt the design of biogas digesters to the local context, meeting the needs of users and using locally available materials; sharing knowledge and information about small-scale biogas technology and its potential would contribute to improving the rate of successful implementation in Southern Africa.

  • 192.
    Mabecua, Fastudo Jorge
    et al.
    Mälardalen University, School of Business, Society and Engineering, Future Energy Center.
    Schwede, Sebastian
    Mälardalen University, School of Business, Society and Engineering, Future Energy Center.
    Lucas, C.
    Department of Chemical Engineering, Eduardo Mondlane University, Maputo, Mozambique.
    Klintenberg, Patrik
    Mälardalen University, School of Business, Society and Engineering, Future Energy Center.
    Agro-waste, a solution for rural electrification?: Assessing biomethane potential of agro-waste in inhambane province, southern mozambique2021In: Water, E-ISSN 2073-4441, Vol. 13, no 7, article id 939Article in journal (Refereed)
    Abstract [en]

    In this study, we investigated the biomethane potential of cassava peels from the four most common varieties of cassava grown in Inhambane Province in Mozambique, Chinhembue, Cussi, Cizangara and Nhassumbi. Agro-wastes from coconut wood and jambolan wood processing were also analyzed to give a complete analysis of the most significant sources of agro-waste in the province. The macromolecular composition (carbohydrates, lipids and proteins) was determined and used to calculate the theoretical maximum biochemical methane potential (BMP). The results show that cassava fiber and cassava peel, which are considered to be waste, are viable resources for biomethane production. Further, the results show that cassava fiber and cassava peel have a higher biomethane potential compared with sawdust, and are therefore more suitable for biomethane production. A study to investigate the effect of toxic cyanogenic glycosides and lignin on cassava peels, using pre-treatment techniques to enhance biogas yield, should be carried out. An estimate of how much electricity can be generated based on the availability of agro-waste (cassava residues) and the amount of biomethane produced in our laboratory experiment was carried out. The amount of electricity that can be produced is enough to provide a valuable contribution to the production process in small and medium sized enterprises (SMEs) and in the cassava industry, or some other use in the rural setting. 

  • 193.
    Madurai Elavarasan, R.
    et al.
    Department of Electrical and Electronics Engineering, Thiagarajar College of Engineering, Madurai, 625015, India.
    Pugazhendhi, R.
    Research & Development Division (Power & Energy), Nestlives Private Limited, Chennai, 600091, India.
    Irfan, M.
    School of Management and Economics, Beijing Institute of Technology, Beijing, 100081, China.
    Mihet-Popa, L.
    Faculty of Electrical Engineering, Ostfold University College, NO-1757, Halden, Norway.
    Khan, I. A.
    Clean and Resilient Energy Systems (CARES) Laboratory, Texas A&M University, Galveston, 77553, TX, United States.
    Campana, Pietro Elia
    Mälardalen University, School of Business, Society and Engineering, Future Energy Center.
    State-of-the-art sustainable approaches for deeper decarbonization in Europe: An endowment to climate neutral vision2022In: Renewable and Sustainable Energy Reviews, ISSN 1364-0321, Vol. 159, article id 112204Article in journal (Refereed)
    Abstract [en]

    Europe anchored aspiring targets in achieving climate neutrality and this motivates the research communities to analyze, investigate and frame strategies to achieve the goals in the stipulated timeframe. This study reviews the effective decarbonization strategies in the context of Europe's climate neutral vision. Initially, the study analyzes the reasons for ever-increasing emissions and investigates the perception of decarbonization in line with various influencing factors such as population size, economic growth, energy intensity, emission intensity, innovation, affordability and time. Subsequently, an in-depth qualitative analysis is performed to force out the challenges that Europe faces in decarbonizing the heating sector from the aspects, such as using clean energy resources, effective heat energy conversion and management approaches. Sustainable approaches and practices are proposed to mitigate carbonization and to promote carbon sink in line with the major problems associated with various sectors such as building, energy, industry and transportation sector. Furthermore, the roles of digitalization in decarbonization are explored and the inherent challenges are also discussed. This study also reviews various decarbonization policies that can direct the governments' action to effectively make a transition towards a climate-neutral society. The key findings highlight that solar energy utilization in small-scale is relatively not preferable for heat energy conversion in Europe due to climatic conditions, while district heating network with bio- and geothermal energy resource highly favors clean heat transformation scenario. In addition, 3D printing has a prodigious role to reduce building lifecycle emissions and hybrid policies as well as reward-based policies yields better outcomes. Promoting hydrogen utilization and carbon capture storage and utilization technologies can pivot climate neutrality in the sectors that are difficult to decarbonize. On the other hand, it can be observed that more focus is provided to reduce emissions and significantly less attention is focused on carbon sink.

  • 194.
    Majidi Nezhad, Meysam
    et al.
    Mälardalen University, School of Business, Society and Engineering, Future Energy Center.
    Neshat, M.
    Center for Artificial Intelligence Research and Optimization, Torrens University Australia, Brisbane, Australia.
    Maher, Azaza
    Mälardalen University, School of Business, Society and Engineering, Future Energy Center.
    Avelin, Anders
    Mälardalen University, School of Business, Society and Engineering, Future Energy Center.
    Piras, G.
    Department of Astronautics, Electrical and Energy Engineering (DIAEE), Sapienza University of Rome, Roma, 00184, Italy.
    Astiaso Garcia, D.
    Department of Planning, Design, Technology of Architecture, Sapienza University of Rome, Via Flaminia 72 – 00196 Rome, Italy.
    Offshore wind farm layouts designer software's2023In: e-Prime - Advances in Electrical Engineering, Electronics and Energy, ISSN 2772-6711, Vol. 4, article id 100169Article in journal (Refereed)
    Abstract [en]

    Offshore wind energy can be considered one of the renewable energy sources with high force potential installed in marine areas. Consequently, the best wind farm layouts identified for constructing combined offshore renewable energy farms are crucial. To this aim, offshore wind potential analysis is essential to highlight the best offshore wind layouts for farm installation and development. Furthermore, the offshore wind farm layouts must be designed and developed based on the offshore wind accurate assessment to identify previously untapped marine regions. In this case, the wind speed distribution and correlation, wind direction, gust speed and gust direction for three sites have been analyzed, and then two offshore wind farm layout scenarios have been designed and analyzed based on two offshore wind turbine types in the Northwest Persian Gulf. In this case, offshore wind farm layouts software and tools have been reviewed as ubiquitous software tools. The results show Beacon M28 and Sea Island buoys location that the highest correlation between wind and gust speeds is between 87% and 98% in Beacon M28 and Sea Island Buoy, respectively. Considerably, the correlation between wind direction and wind speed is negligible. The Maximum likelihood algorithm, the WAsP algorithm, and the Least Squares algorithm have been used to analyze the wind energy potential in offshore buoy locations of the Northwest Persian Gulf. In addition, the wind energy generation potential has been evaluated in different case studies. For example, the Umm Al-Maradim buoy area has excellent potential for offshore wind energy generation based on the Maximum likelihood algorithm, WAsP algorithm, and Least Squares algorithm.

  • 195.
    Majidi Nezhad, Meysam
    et al.
    Mälardalen University, School of Business, Society and Engineering, Future Energy Center.
    Neshat, M.
    Center for Artificial Intelligence Research and Optimization, Torrens University Australia, Brisbane, Australia .
    Sylaios, G.
    Laboratory of Ecological Engineering and Technology, Department of Environmental Engineering, Democritus University of Thrace, Xanthi, 67100, Greece.
    Astiaso Garcia, D.
    Department of Planning, Design, Technology of Architecture, Sapienza University of Rome, Via Flaminia 72, Rome, 00196, Italy .
    Marine energy digitalization digital twin's approaches2024In: Renewable & sustainable energy reviews, ISSN 1364-0321, E-ISSN 1879-0690, Vol. 191, article id 114065Article in journal (Refereed)
    Abstract [en]

    Digital twins (DTs) promise innovation for the marine renewable energy sector using modern technological advances and the existing maritime knowledge frameworks. The DT is a digital equivalent of a real object that reflects and predicts its behaviours and states in a virtual space over its lifetime. DTs collect data from multiple sources in pilots and leverage newly introduced low-cost sensor systems. They synchronize, homogenize, and transmit the data to a central hub and integrate it with predictive and learning models to optimize plant performance and operations. This research presents critical aspects of DT implementation challenges in marine energy digitalization DT approaches that use and combine data systems. Firstly, the DT and the existing framework for marine knowledge provided by systems are presented, and the DT's main development steps are discussed. Secondly, the DT implementing main stages, measurement systems, data harmonization and preprocessing, modelling, comprehensive data analysis, and learning and optimization tools, are identified. Finally, the ILIAD (Integrated Digital Framework for Comprehensive Maritime Data and Information Services) project has been reviewed as a best EU funding practice to understand better how marine energy digitalization DT's approaches are being used, designed, developed, and launched. 

  • 196.
    Malovanyy, Andriy
    et al.
    IVL Svenska Miljöinstitutet, Sweden.
    Johannesdottir, Solveig
    RISE, Sweden.
    Schwede, Sebastian
    Mälardalen University, School of Business, Society and Engineering, Future Energy Center.
    Ahlgren, Serina
    RISE, Sweden.
    Flodin, Elin
    RISE, Sweden.
    Shanmugam, Kavitha
    RISE, Sweden.
    Återvinning av näringsämnen från avlopp: En litteraturstudie2022Report (Other academic)
    Abstract [en]

    The report describes established and new technologies for nitrogen recovery from wastewater andcompares the nitrogen recovery methods with other ways of producing nitrogen fertilizer in terms ofclimate impact and costs. The report also includes a brief review of opportunities for potassium andsulfur recovery and a status update of phosphorus recovery methods.

  • 197.
    Manova, S.
    et al.
    King Mongkut's University of Technology Thonburi (KMUTT), Bangkok, Bangmod, Thailand.
    Kumar, J. P.
    Department of Mechanical Engineering, Kings Engineering College, Chennai, India.
    Asirvatham, L. G.
    Department of Mechanical Engineering, Karunya Institute of Technology and Sciences, Coimbatore, India.
    Angeline, A. A.
    Department of Robotics Engineering, Karunya Institute of Technology and Sciences, Coimbatore, India.
    Leunanonchai, W.
    King Mongkut's University of Technology Thonburi (KMUTT), Bangkok, Bangmod, Thailand.
    Arkadumnuay, T.
    King Mongkut's University of Technology Thonburi (KMUTT), Bangkok, Bangmod, Thailand.
    Mesgarpour, Mehrdad
    Mälardalen University, School of Business, Society and Engineering, Future Energy Center.
    Mahian, O.
    Ningbo University, Ningbo, China.
    Wongwises, S.
    King Mongkut's University of Technology Thonburi (KMUTT), Bangkok, Bangmod, Thailand.
    Experimental investigation of heat transfer characteristics in a miniature flat heat pipe with multi-channels2024In: International Journal of Heat and Mass Transfer, ISSN 0017-9310, E-ISSN 1879-2189, Vol. 221, article id 125066Article in journal (Refereed)
    Abstract [en]

    The heat transfer characteristics of a miniatured flat heat pipe (MFHP) with multi-channels, featuring a port diameter of 1.18 mm, is investigated experimentally. Various operating parameters are considered, including the working fluid volume (Vf = 1.5, 2.5, and 3.5 ml), length of the liquid reservoir (Lres = No reservoir, 5, and 10 mm), orientation such as axial face (αa) or lateral side (αl), inclination angles (α = −15 to 90o), and cooling water flow rates (ṁi = 10, 15, and 20 LPH). Based on the experiments, the optimal values for the working fluid volume, reservoir length, and flow rate are determined as Vf = 2.5 ml, Lres = 5 mm, and ṁi = 20 LPH, respectively. Further analysis reveals that, the heat dissipation rate for the axial face is significantly higher than that of the lateral side, with an average percentage increase of 35.4 %. However, the lateral side outperforms the axial face in terms of stabilizing the evaporator wall temperature, reducing fluctuations by an average of 24.5 %. Moreover, the presence of multi-channels allows the MFHP in axial face orientation to dissipate a maximum heat load of 15 W against gravity at an inclination angle of αa = −15o. Finally, the variations in MFHP operation based on the orientation and its underlying physical mechanisms that contribute to enhancing heat transfer are discussed.

  • 198.
    Mao, M.
    et al.
    Department of Electrical and Electronic Engineering, Imperial College London, London, SW7 2AZ, United Kingdom.
    Chen, S.
    School of Electrical Engineering, Chongqing University, Chongqing, 400044, China.
    Yan, Jinyue
    Mälardalen University, School of Business, Society and Engineering, Future Energy Center. Department of Building Environment and Energy Engineering, The Hong Kong Polytechnic University, Hong Kong.
    Modelling pavement photovoltaic arrays with cellular automata2023In: Applied Energy, ISSN 0306-2619, E-ISSN 1872-9118, Vol. 330, article id 120360Article in journal (Refereed)
    Abstract [en]

    This paper proposes a dynamic modelling of two-lane pavement photovoltaic (PV) arrays based on cellular automata theory, and the influence of random vehicle shadows on the output characteristics is explored and analysed. In the proposed model, a mathematical model of two-lane pavement PV array is established with considering the influence of bypass diodes and blocking diodes. In order to characterize the change of irradiation intensity caused by vehicle shadow, an asymmetric two-lane Nagel-Scheckenberg (ATNS) model is introduced in the driving process of vehicles. Moreover, the vehicle position at each time is obtained to further establish the randomly changing vehicle shadow matrix. The actual irradiance matrix can be obtained by combining vehicle shadow matrix with the irradiance matrix related to the external environment, and then a dynamic model of two-lane pavement PV arrays is established. To evaluate the effectiveness of the proposed model, the influence of the slowing probability and shading degree on the proposed model is analysed, where three representative scenarios are set to study the randomness of vehicle shading and its effects. Finally, simulations and experiments are conducted and the results show that the slowing probability and shading degree are the key two factors on the output characteristics of two-lane pavement PV arrays, and the dynamic random vehicle shadows significantly affect the output characteristics, resulting in a changing multi-peak state of the power-voltage curve and the global maximum power point being in a floating fast-changing state. © 2022

  • 199.
    Marais, Heidi Lynn
    et al.
    Mälardalen University, School of Business, Society and Engineering, Future Energy Center.
    Zaccaria, Valentina
    Mälardalen University, School of Business, Society and Engineering, Future Energy Center.
    Ivan, Jean-Paul A.
    Örebro University, Sweden.
    Nordlander, Eva
    Detectability of Fault Signatures in a Wastewater Treatment Process2022In: Proceedings of The First SIMS EUROSIM Conference on Modelling and Simulation, SIMS EUROSIM 2021, and 62nd International Conference of Scandinavian Simulation Society, SIMS 2021 / [ed] Esko Juuso, Bernt Lie, Erik Dahlquist and Jari Ruuska, 2022, p. 418-423Conference paper (Refereed)
    Abstract [en]

    In a wastewater treatment plant reliable fault detection is an integral component of process supervision and ensuring safe operation of the process. Detecting and isolating process faults requires that sensors in the process can be used to uniquely identify such faults. However, sensors in the wastewater treatment process operate in hostile environments and often require expensive equipment and maintenance. This work addresses this problem by identifying a minimal set of sensors which can detect and isolate these faults in the Benchmark Simulation Model No. 1.Residual-based fault signatures are used to determine this sensor set using a graph-based approach; these fault signatures can be used in future work developing fault detection methods. It is recommended that further work investigate what sizes of faults are critical to detect based on their potential effects on the process, as well as ways to select an optimal sensor set from multiple valid configurations.

  • 200.
    Marais, Heidi Lynn
    et al.
    Mälardalen University, School of Business, Society and Engineering, Future Energy Center.
    Zaccaria, Valentina
    Mälardalen University, School of Business, Society and Engineering, Future Energy Center.
    Odlare, Monica
    Mälardalen University, School of Business, Society and Engineering, Future Energy Center.
    Comparing statistical process control charts for fault detection in wastewater treatment2022In: Water Science and Technology, ISSN 0273-1223, E-ISSN 1996-9732, Vol. 85, no 4, p. 1250-1262Article in journal (Refereed)
    Abstract [en]

    Fault detection is an important part of process supervision, especially in processes where there are strict requirements on the process outputs like in wastewater treatment. Statistical control charts such as Shewhart charts, cumulative sum (CUSUM) charts, and exponentially weighted moving average (EWMA) charts are common univariate fault detection methods. These methods have different strengths and weaknesses that are dependent on the characteristics of the fault. To account for this the methods in their base forms were tested with drift and bias sensor faults of different sizes to determine the overall performance of each method. Additionally, the faults were detected using two different sensors in the system to see how the presence of active process control influenced fault detectability. The EWMA method performed best for both fault types, specifically the drift faults, with a low false alarm rate and good detection time in comparison to the other methods. It was shown that decreasing the detection time can effectively reduce excess energy consumption caused by sensor faults. Additionally, it was shown that monitoring a manipulated variable has advantages over monitoring a controlled variable as setpoint tracking hides faults on controlled variables; lower missed detection rates are observed using manipulated variables.

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