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  • 1.
    Azimoh, Chukwuma Leonard
    et al.
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Klintenberg, Patrik
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Wallin, Fredrik
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Karlsson, Björn
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Mbohwa, Charles
    University of Johannesburg, South Africa.
    Electricity for development:: Mini-grid solution for rural electrificationin South Africa2016Ingår i: Energy Conversion and Management, ISSN 0196-8904, E-ISSN 1879-2227, nr 110, s. 268-277Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The objective of most rural electrification programs in the developing world is to bring about socioeconomicdevelopment to households. Governments have put in place a number of measures to achievethis goal. Previous studies on rural electrification programs in developing countries show that solar homesystems and mini-grid systems are the dominant technologies. Assessments of a pilot hybrid mini-gridproject at Lucingweni village have concluded that mini-grid projects are not feasible due to high electricityproduction costs. As a result efforts toward rural electrification have been focused on the solar homesystem. Nevertheless, previous studies of the South African solar home system program have shown thatthe development objectives of the program are yet to be met more than a decade after commissioning.Therefore, this study investigates the viability of a hybrid mini-grid as a solution for rural developmentin South Africa. Investigations were based on Lucingweni and Thlatlaganya, two rural Villages where themini-grid and solar home system have been introduced. The mini-grid systems were designed taking intoconsideration available natural resources and existing load profiles. The results show that a village of 300households needs about 2.4 kW h/household/day of electricity to initiate and sustain income generatingactivities and that the solar home system is not capable of supporting this level of demand. We also showthat in locations with hydro resources, a hybrid mini-grid system has the most potential for meeting theenergy needs of the households in a cost effective manner. The assessment shows that with adequateplanning and optimization of available resources, the cost of electricity production can be reduced.

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  • 2.
    Behzadi, A.
    et al.
    Department of Civil and Architectural Engineering, KTH Royal Institute of Technology, Stockholm, Sweden.
    Thorin, Eva
    Mälardalens universitet, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Duwig, C.
    Department of Chemical Engineering, KTH Royal Institute of Technology, Stockholm, Sweden.
    Sadrizadeh, S.
    Department of Civil and Architectural Engineering, KTH Royal Institute of Technology, Stockholm, Sweden.
    Supply-demand side management of a building energy system driven by solar and biomass in Stockholm: A smart integration with minimal cost and emission2023Ingår i: Energy Conversion and Management, ISSN 0196-8904, E-ISSN 1879-2227, Vol. 292, artikel-id 117420Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    As part of the transition to a sustainable future, energy-efficient buildings are needed to secure users' comfort and lower the built environment's energy footprint and associated emissions. This article presents a novel, realistic and affordable solution to minimize the footprint of smart building energy systems and enable higher renewable energy use in the building sector. For this, an intelligent system is being developed using a rule-based automation approach that considers thermal comfort, energy prices, meteorological data, and primary energy use. In order to lower the installation cost and part of the environmental footprint, batteries are not used, and the heat pump's size is decreased via component integration. Also, different renewable resources are effectively hybridized using photovoltaic thermal panels and an innovative biomass heater to increase the share of renewable energy, enhance reliability, and shave peak load. In order to secure feasibility, the suggested framework is assessed from the techno-economic and environmental standpoints for 100 residential apartments in Stockholm, Sweden. Our results show that 70.8 MWh of renewable electricity is transferred to the local grid, and the remaining 111.5 MWh is used to supply the building's needs and power the electrically-driven components. The biomass heater meets more than 65% of the space heating demand, mainly at low solar power and high electricity prices, illustrating the value of integration strategies to reduce the system's dependability on the local grid. The results further reveal that most energy purchases during the cloudy days and nights are repaid through the sale of excess renewable production during the warmer hours, with a bidirectional connection with the grid. The monthly energy cost is less than 140 $/MWh for most of the years. The cost can be held low due to the exclusion of batteries and minimizing the heat pump size. The proposed system has a low emission index of 11.9 kgCO2/MWh and can reduce carbon dioxide emissions by 70 TCO2/year compared to using the supply from the Swedish energy mix. 

  • 3.
    Behzadi, Amirmohammad
    et al.
    KTH Univ, Dept Civil & Architectural Engn, Stockholm, Sweden..
    Gholamian, Ehsan
    Univ Tabriz, Fac Mech Engn, Tabriz, Iran..
    Alirahmi, Seyed Mojtaba
    Aalborg Univ, Dept Chem & Biosci, DK-6700 Esbjerg, Denmark..
    Nourozi, Behrouz
    KTH Univ, Dept Civil & Architectural Engn, Stockholm, Sweden..
    Sadrizadeh, Sasan
    Mälardalens universitet, Akademin för ekonomi, samhälle och teknik, Framtidens energi. KTH Univ, Dept Civil & Architectural Engn, Stockholm, Sweden.;Malardalen Univ, Sch Business Soc & Engn, S-72123 Vasteras, Sweden..
    A comparative evaluation of alternative optimization strategies for a novel heliostat-driven hydrogen production/injection system coupled with a vanadium chlorine cycle2022Ingår i: Energy Conversion and Management, ISSN 0196-8904, E-ISSN 1879-2227, Vol. 267, artikel-id 115878Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    This paper introduces an innovative and cost-effective multi-generation plant, driven by the central receiverbased concentrated solar systems, to facilitate the desired global green-transition process. The vanadium chlorine thermochemical cycle, which uses hydrogen instead of natural gas in the combustion chamber, is used as an innovative approach for reducing greenhouse gas emissions. The proposed system also includes a thermoelectric generator (TEG) for excess power generation and a multi-effect desalination (MED) unit to reduce exergy loss. The suggested system's technological, economic, and environmental metrics are analyzed and compared to a similar system that stores the created hydrogen rather than burning it in the combustion chamber. Furthermore, the viability of the studied model is investigated under the optimal operating condition, using the example of Sevilla in order to make the conclusions more reliable. According to the findings, the suggested novel configuration is a better alternative in terms of cost and environmental impact owing to decreased product energy costs and CO2 emissions. The outcomes further indicate that the substitution of the condenser with TEG leads to considerably higher power production. According to the optimization findings, the multi-objective grey wolf algorithm is the best optimization strategy compared to the non-dominated genetic and particle swarm approaches. At the best optimization point, 2.5% higher exergy efficiency, 1 $/GJ cheaper product energy cost, and 0.12 kg/kWh lower levelized CO2 emission are achieved compared to the operating condition. The Sankey diagram indicates that the solar heliostat system has the highest irreversibility. The exergy analysis results further reveal that the flue gas condensation process through the Rankine cycle and MED unit lead to a 53.2% reduction in exergy loss. Finally, considerable CO2 emission reductions show that the suggested new method is an effective solution for cleaner energy production in warmer climate countries.

  • 4.
    Behzadi, Amirmohammad
    et al.
    KTH University, Stockholm, Sweden.
    Sadrizadeh, Sasan
    Mälardalens universitet, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    A rule-based energy management strategy for a low-temperature solar/wind-driven heating system optimized by the machine learning-assisted grey wolf approach2023Ingår i: Energy Conversion and Management, ISSN 0196-8904, E-ISSN 1879-2227, Vol. 277, artikel-id 116590Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    This work presents an innovative, practical, and cost-effective solution for advancing state-of-the-art intelligent building energy systems and aiding the intended worldwide green transition with maximum renewable integration. The vanadium chloride cycle, electrolyzer unit, and Alkaline fuel cell are powered by the sun's and wind's energy to produce/store/use hydrogen. A rule-based control scheme is designed to provide a sophisticated interplay between the demand/supply sides, components, and local energy networks to reduce peak capacity, lower emissions, and save energy costs. TRNSYS is used to analyze and compare the techno-economic-environmental indicators of the conventional system and the suggested smart model for a multi-family building in Sweden. A grey wolf method is built in MATLAB with the help of machine learning to determine the optimum operating state with the maximum accuracy and the least amount of computational time. The results reveal that the suggested smart model considerably saves energy and money compared to the conventional system in Sweden while lowering CO2 emissions. According to the optimization results, the grey wolf optimizer and machine learning techniques enable greater total efficiency of 13 %, higher CO2 mitigation of 8 %, a larger cost saving of 38 %, and a reduced levelized energy cost of 41 $/MWh. The scatter distribution of important design parameters shows that altering the fuel cell current and electrode area considerably impacts the system's performance from all angles. The bidirectional connection of the proposed smart system with the heating and electrical networks through the rule-based controller demonstrates that it can supply the building's energy requirements for more than 300 days of the year. Eventually, the major contribution of the vanadium chloride cycle in the summer and the electrolyzer in the winter to the creation of hydrogen highlights the significance of renewable hybridization in reducing the dependence of buildings on energy networks.

  • 5.
    Campana, Pietro Elia
    et al.
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Cioccolanti, L.
    Centro di Ricerca per l'Energia, l'Ambiente e il Territorio, Università Telematica eCampus, Novedrate (CO), 22060, Italy.
    François, B.
    Department of Civil and Environmental Engineering, University of Massachusetts Amherst, Amherst, MA 01003, United States.
    Jurasz, Jakob
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi. Faculty of Management, AGH University, Kraków, 30-059, Poland; Faculty of Environmental Engineering, Wroclaw University of Science and Technology, Wroclaw, 50-370, Poland.
    Zhang, Y.
    Department of Chemical Engineering, KTH Royal Institute of Technology, Stockholm, 10044, Sweden.
    Varini, M.
    Department of Chemical Engineering, KTH Royal Institute of Technology, Stockholm, 10044, Sweden.
    Stridh, Bengt
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Yan, Jinyue
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Li-ion batteries for peak shaving, price arbitrage, and photovoltaic self-consumption in commercial buildings: A Monte Carlo Analysis2021Ingår i: Energy Conversion and Management, ISSN 0196-8904, E-ISSN 1879-2227, Vol. 234, artikel-id 113889Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    This study investigates the benefits of introducing Li-ion batteries as energy storage unit in the commercial sector by considering a representative building with a photovoltaic system. Only the costs and revenues related to the installation and operation of the battery are considered in this study. The operational strategy of the battery consists in balancing the following processes through day-ahead forecasts for both electricity consumption and photovoltaic production: shaving a targeted peak, performing price arbitrage, and increasing photovoltaic self-consumption. By reviewing the electricity price cost for commercial buildings from several companies around the world, a general electricity price structure is defined. Afterwards, a Monte Carlo Analysis is applied for three locations with different solar irradiation levels to study the impact of climate, electricity price components, and other seven sensitive parameters on the economic viability of Li-ion batteries. The Monte Carlo Analysis shows that the most sensitive parameters for the net present value are the battery capacity, the battery price, and the component of the electricity price that relates to the peak power consumption. For Stockholm, one of the investigated locations, the corresponding Pearson correlation coefficients are −0.67, −0.66, and 0.19 for the case were no photovoltaic system is installed. For the considered battery operational strategies, the current investment and annual operation costs for the Li-ion battery always lead to negative net present values independently of the location. Battery prices lower than 250 US$/kWh start to manifest positive net present values when combining peak shaving, price arbitrage, and photovoltaic self-consumption. However, the integration of a photovoltaic system leads to a reduced economic viability of the battery by reducing the revenues generated by the battery while performing peak shaving.

  • 6.
    Campana, Pietro Elia
    et al.
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Holmberg, Aksel
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Pettersson, Oscar
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Klintenberg, Patrik
    Hangula, A.
    Namibia Energy Institute, Namibia University of Science and Technology, Windhoek, Namibia.
    Araoz, F. B.
    School of Chemical Science & Engineering, KTH Royal Institute of Technology, Teknikringen 42, Stockholm, Sweden.
    Zhang, Y.
    School of Chemical Science & Engineering, KTH Royal Institute of Technology, Teknikringen 42, Stockholm, Sweden.
    Stridh, Bengt
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi. ABB AB, Corporate Research, Västerås, Sweden.
    Yan, Jinyue
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi. School of Chemical Science & Engineering, KTH Royal Institute of Technology, Teknikringen 42, Stockholm, Sweden.
    An open-source optimization tool for solar home systems: A case study in Namibia2016Ingår i: Energy Conversion and Management, ISSN 0196-8904, E-ISSN 1879-2227, Vol. 130, nr 15, s. 106-118Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Solar home systems (SHSs) represent a viable technical solution for providing electricity to households and improving standard of living conditions in areas not reached by the national grid or local grids. For this reason, several rural electrification programmes in developing countries, including Namibia, have been relying on SHSs to electrify rural off-grid communities. However, the limited technical know-how of service providers, often resulting in over- or under-sized SHSs, is an issue that has to be solved to avoid dissatisfaction of SHSs’ users. The solution presented here is to develop an open-source software that service providers can use to optimally design SHSs components based on the specific electricity requirements of the end-user. The aim of this study is to develop and validate an optimization model written in MS Excel-VBA which calculates the optimal SHSs components capacities guaranteeing the minimum costs and the maximum system reliability. The results obtained with the developed tool showed good agreement with a commercial software and a computational code used in research activities. When applying the developed optimization tool to existing systems, the results identified that several components were incorrectly sized. The tool has thus the potentials of improving future SHSs installations, contributing to increasing satisfaction of end-users.

  • 7.
    Campana, Pietro Elia
    et al.
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Li, Hailong
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Zhang, J.
    Institute of Water Resources and Hydropower Research, Beijing, China .
    Liu, J.
    Institute of Water Resources and Hydropower Research, Beijing, China .
    Yan, Jinyue
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Economic optimization of photovoltaic water pumping systems for irrigation2015Ingår i: Energy Conversion and Management, ISSN 0196-8904, E-ISSN 1879-2227, Vol. 95, s. 32-41Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Photovoltaic water pumping technology is considered as a sustainable and economical solution to provide water for irrigation, which can halt grassland degradation and promote farmland conservation in China. The appropriate design and operation significantly depend on the available solar irradiation, crop water demand, water resources and the corresponding benefit from the crop sale. In this work, a novel optimization procedure is proposed, which takes into consideration not only the availability of groundwater resources and the effect of water supply on crop yield, but also the investment cost of photovoltaic water pumping system and the revenue from crop sale. A simulation model, which combines the dynamics of photovoltaic water pumping system, groundwater level, water supply, crop water demand and crop yield, is employed during the optimization. To prove the effectiveness of the new optimization approach, it has been applied to an existing photovoltaic water pumping system. Results show that the optimal configuration can guarantee continuous operations and lead to a substantial reduction of photovoltaic array size and consequently of the investment capital cost and the payback period. Sensitivity studies have been conducted to investigate the impacts of the prices of photovoltaic modules and forage on the optimization. Results show that the water resource is a determinant factor.

    Ladda ner fulltext (pdf)
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  • 8.
    Campana, Pietro Elia
    et al.
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Mainardis, M.
    Department Polytechnic of Engineering and Architecture (DPIA), Via del Cotonificio 108, University of Udine, Udine, 33100, Italy.
    Moretti, A.
    Department Polytechnic of Engineering and Architecture (DPIA), Via del Cotonificio 108, University of Udine, Udine, 33100, Italy.
    Cottes, M.
    Department Polytechnic of Engineering and Architecture (DPIA), Via del Cotonificio 108, University of Udine, Udine, 33100, Italy.
    100% renewable wastewater treatment plants: Techno-economic assessment using a modelling and optimization approach2021Ingår i: Energy Conversion and Management, ISSN 0196-8904, E-ISSN 1879-2227, Vol. 239, artikel-id 114214Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Renewable energies are being given increasing attention worldwide, as they are able to reduce the dependence on depletable fossil fuels. At the same time, wastewater treatment is known to be a significantly energy-intensive sector, which could potentially exploit renewable energies conversion in different forms. This study investigated the feasibility to design high renewable share wastewater treatment plants through dynamic simulations and optimization, aiming to move towards greener and energy-wise wastewater remediation processes. The main aim of the work was achieved by integrating photovoltaic systems with wind turbines, multi-energy storage technologies, i.e., batteries and hydrogen systems, and reverse osmosis tertiary treatment to absorb the power production surpluses. It was supposed that, in the newly proposed scenario, most of the plant electricity need would be covered by renewable energy. The optimization problem was multi-objective and found the trade-off solutions between minimizing the net present cost and maximizing the renewable share. In the first part of the study, the model was developed and applied to a medium-scale Italian municipal wastewater treatment plant. Model generalization was successively accomplished by applying the model to different locations and plant scales across the world. For all the investigated scenarios and cases, the optimal system integration was to design a renewable and storage system with a renewable share of 70%, corresponding to the lowest net present cost. The developed model is highly flexible and can be applied to other relevant case studies, boosting for a more sustainable wastewater treatment sector, enhancing at the same time local renewable energy conversion. 

  • 9.
    Campana, Pietro Elia
    et al.
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Mainardis, Matia
    Univ Udine, Dept Polytechn Engn & Architecture DPIA, Via Cotonificio 108, I-33100 Udine, Italy.
    Moretti, Alessandro
    Univ Udine, Dept Polytechn Engn & Architecture DPIA, Via Cotonificio 108, I-33100 Udine, Italy.
    Cottes, Mattia
    Univ Udine, Dept Polytechn Engn & Architecture DPIA, Via Cotonificio 108, I-33100 Udine, Italy.
    Corrigendum to “100% renewable wastewater treatment plants: Techno-economic assessment using a modelling and optimization approach” [Energy Convers. Manage. 239 (2021) 114214] (Energy Conversion and Management (2021) 239, (S0196890421003903), (10.1016/j.enconman.2021.114214))2021Ingår i: Energy Conversion and Management, ISSN 0196-8904, E-ISSN 1879-2227, Vol. 244, artikel-id 114531Artikel i tidskrift (Refereegranskat)
  • 10.
    Dai, B.
    et al.
    Tianjin Key Laboratory of Refrigeration Technology, Tianjin University of Commerce, Tianjin, China.
    Qi, H.
    Tianjin Key Laboratory of Refrigeration Technology, Tianjin University of Commerce, Tianjin, China.
    Liu, S.
    Tianjin Key Laboratory of Refrigeration Technology, Tianjin University of Commerce, Tianjin, China.
    Ma, M.
    Tianjin Key Laboratory of Refrigeration Technology, Tianjin University of Commerce, Tianjin, China.
    Zhong, Z.
    Foreign Economic Cooperation Office, Ministry of Ecology and Environment of the People's Republic of China, Beijing, China.
    Li, Hailong
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi. Tianjin Key Laboratory of Refrigeration Technology, Tianjin University of Commerce, Tianjin, China.
    Song, M.
    Department of Human and Engineered Environmental Studies, The University of Tokyo, Chiba, Japan.
    Sun, Z.
    Tianjin Key Laboratory of Refrigeration Technology, Tianjin University of Commerce, Tianjin, China.
    Evaluation of transcritical CO 2 heat pump system integrated with mechanical subcooling by utilizing energy, exergy and economic methodologies for residential heating2019Ingår i: Energy Conversion and Management, ISSN 0196-8904, E-ISSN 1879-2227, Vol. 192, s. 202-220Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    A transcritical CO 2 heat pump (HP) system for residential space heating integrated with direct dedicated mechanical subcooling (DMS) is proposed, and mathematical models are developed to study the annual energetic and economic performances considering the influence of frosting. The operation characteristics by adopting different heating terminals used in five typical cities are also assessed. The results show a maximum coefficient of performance (COP) is achieved at the optimum discharge pressure and subcooling degree. The COP is promoted by 24.4% and the discharge pressure is decreased by 2.093 MPa at the ambient temperature of −10 °C and water supply/return temperature of 45/40 °C. The seasonal performance factor (SPF) is enhanced more noticeably for severe cold region. For the case of Harbin using floor-coil radiator (FCR) or normal fan-coil unit (N-FCU) as heating terminal, SPF is improved by 32.0%. The highest SPF is achieved when small temperature difference fan-coil unit (STD-FCU) is employed. The exergy efficiency can also be apparently improved, especially for the cities located in severe cold region and using FCR or N-FCU as heating terminal due to the reduction in throttling loss of CO 2 system. The purchased equipment cost and electricity cost of the CO 2 HP with DMS are both lower than those of traditional CO 2 heat pump system. The CO 2 HP DMS system using STD-FCU as heating terminal shows superior economical efficiency to traditional system, with levelized annual total cost reduced by 7.51–15.27%. 

  • 11.
    Dai, Baomin
    et al.
    Tianjin Univ Commerce, Tianjin Key Lab Refrigerat Technol, Tianjin 300134, Peoples R China..
    Qi, Haifeng
    Tianjin Univ Commerce, Tianjin Key Lab Refrigerat Technol, Tianjin 300134, Peoples R China..
    Liu, Shengchun
    Tianjin Univ Commerce, Tianjin Key Lab Refrigerat Technol, Tianjin 300134, Peoples R China..
    Zhong, Zhifeng
    Minist Ecol & Environm Peoples Republ China, Foreign Econ Cooperat Off, Beijing, Peoples R China..
    Li, Hailong
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi. Tianjin Univ Commerce, Tianjin Key Lab Refrigerat Technol, Tianjin 300134, Peoples R China.
    Song, Mengjie
    Univ Tokyo, Dept Human & Engn Environm Studies, Chiba 2778563, Japan..
    Ma, Muyu
    Tianjin Univ Commerce, Tianjin Key Lab Refrigerat Technol, Tianjin 300134, Peoples R China..
    Sun, Zhili
    Tianjin Univ Commerce, Tianjin Key Lab Refrigerat Technol, Tianjin 300134, Peoples R China..
    Environmental and economical analyses of transcritical CO2 heat pump combined with direct dedicated mechanical subcooling (DMS) for space heating in China2019Ingår i: Energy Conversion and Management, ISSN 0196-8904, E-ISSN 1879-2227, Vol. 198, artikel-id 111317Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    An environmental and economical assessment model is developed, in order to evaluate the performances of transcritical CO2 heat pump system with dedicated mechanical subcooling (CO2 HPDMS). Introducing DMS to traditional CO2 HP system is an efficient method to reduce the primary energy consumption, which can be further decreased by using small temperature difference fan-coil unit (STD-FCU) as heating terminal. Using CO2 heat pump system for space heating is an environmentally-friendly heating method. The corresponding pollution emissions are only inferior to those of the wall hanging gas heater. The initial capital cost and operating cost of CO2 HPDMS system are both lower than those of CO2 HPBASE system, and the CO2 compressor cost accounts for about 80% of the overall initial capital cost. In contrast to other traditional heating methods, the payback periods of CO2 HPDMS system are not more than 9 years in most cases. If the CO2 compressor and electricity price are reduced by 20% and 28.79% respectively, the life cycle cost of CO2 HPDMS will be competitive to that of coal-fired boiler. In China, it is a promising way to adopt CO2 HPDMS for space heating in the near future with the assistant of electricity price subsidy and compressor price reduction.

  • 12.
    Daraei, Mahsa
    et al.
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Campana, Pietro Elia
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Avelin, Anders
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Jurasz, Jakub
    Wroclaw University of Science and Technology, Wroclaw, 50-370, Poland.
    Thorin, Eva
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Impacts of integrating pyrolysis with existing CHP plants and onsite renewable-based hydrogen supply on the system flexibility2021Ingår i: Energy Conversion and Management, ISSN 0196-8904, E-ISSN 1879-2227, Vol. 43, artikel-id 114407Artikel i tidskrift (Övrigt vetenskapligt)
    Abstract [en]

    The share of renewable energy sources in the primary energy use is increasing worldwide. Given the intermittency of the energy supply from renewables, it is important to increase flexibility in the system to respond to the imbalances between energy demand and supply. Several flexibility options such as power storage and energy integration are currently in use, mostly at small scales. The increased energy supply from renewables and the flexibility solutions can influence the production planning of existing thermal energy conversion plants. In this study, integration of energy technologies including a hydrotreated pyrolysis oil production integrated with existing CHP plants is investigated as a flexibility solution. The system interacts with potential power generation from rooftop PV systems integrated with power-to-hydrogen storage. A cost-optimization model is developed using MILP method. The study focuses on the system flexibility and operational strategy of the existing CHP plants considering market trends, climate changes, and future energy developments with increased penetration of heat pumps and electric vehicles but less fossil fuels use. The results indicate that the suggested integrated system can increase the local energy supply by 33 GWh. Moreover, the power-to-hydrogen storage and onsite hydrogen use can increase the share of renewables in energy supply by 6%. Optimization of the developed scenarios for future energy-related changes indicates that the market trends could significantly reduce the performance of the system by 21% but increase the penetration of renewables in the system by 8%. Overall, scenario analysis shows the potential of using such a polygeneration system for flexible energy supply including existing CHP plants. 

  • 13.
    Guezgouz, M.
    et al.
    Department of Electrical Engineering, Mostaganem University, Mostaganem, Algeria.
    Jurasz, Jakob
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi. Faculty of Management, Department of Engineering Management, AGH University.,Cracow, Poland.
    Bekkouche, B.
    Department of Electrical Engineering, Mostaganem University, Mostaganem, Algeria.
    Ma, T.
    School of Mechanical Engineering, Shanghai Jiao Tong University, China.
    Javed, M. S.
    School of Mechanical Engineering, Shanghai Jiao Tong University, China.
    Kies, A.
    Frankfurt Institute for Advanced Studies, Goethe University Frankfurt, Frankfurt am Main, Germany.
    Optimal hybrid pumped hydro-battery storage scheme for off-grid renewable energy systems2019Ingår i: Energy Conversion and Management, ISSN 0196-8904, E-ISSN 1879-2227, Vol. 199, artikel-id 112046Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The development of energy storage systems paves the way towards a high integration of renewable energy sources in the electricity generation sector. Considering above, this paper introduces a new energy management strategy to efficiently coordinate a hybrid energy storage system based on pumped hydro storage (long term bulk storage) with batteries (short term, more flexible). For the purpose of this analysis, hourly time series of irradiation, wind speed, temperature and real measured load (characteristic for farmstead) covering one year were gathered for the selected site in Algeria. The optimal size of the system is determined based on a multi-objective optimization using a grey wolf optimizer implemented in MATLAB software. The results indicate that the hybrid storage system enables achieving higher reliability at lower cost in comparison to a system with single storage technology. The use of hybrid storage also reduces the curtailment of renewable generation. Further findings reveal that the cost of an optimal energy supply system with 97.5% reliability is 0.162 €/kWh, 0.207 €/kWh and 1.462 €/kWh for hybrid storage, battery and pumped storage, respectively. However, sensitivity analysis shows that the optimal hybrid storage configuration is less resilient when changes in irradiation/temperature/load are considered. This indicates that special actions (upscale of installed power) must be undertaken to avoid lower performance of hybrid storage systems. In summary, the hybrid storage system seems to be better sized for consideration in optimized solar/wind conditions, but by avoiding oversizing they are less resilient to future potential changes in renewable energy availability.

  • 14.
    Guo, S.
    et al.
    Inner Mongolia University of Science and Technology, Baotou, China.
    Liu, Q.
    Chinese Academy of Sciences, Beijing, China.
    Zhao, J.
    Tianjin University, Tianjin, China.
    Jin, G.
    Inner Mongolia University of Science and Technology, Baotou, 014010, China.
    Wu, W.
    Inner Mongolia University of Science and Technology, Baotou, China.
    Yan, Jinyue
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi. Royal Institute of Technology (KTH), Stockholm, Sweden.
    Li, Hailong
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Jin, H.
    Chinese Academy of Sciences, Beijing, China.
    Mobilized thermal energy storage: Materials, containers and economic evaluation2018Ingår i: Energy Conversion and Management, ISSN 0196-8904, E-ISSN 1879-2227, Vol. 177, s. 315-329Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The transportation of thermal energy is essential for users who are located far away from heat sources. The networks connecting them achieve the goal in efficient heat delivery and reasonable cost, especially for the users with large heat demands. However, it is difficult to satisfy the heat supply of the detached or emergent users with the existing pipelines. Therefore, a promising alternative, called mobilized thermal energy storage (M-TES), was proposed to deliver the heat flexibly without the restriction of networks. In this paper, a review of studies on M-TES is conducted in terms of materials, containers and economic evaluation. The potential candidates of materials, such as sugar alcohols, hydrated salts, alkalies and zeolite are reviewed and compared based on their thermophysical properties, price, advantages and disadvantages. Various containers, including the shell-and-tube, encapsulated, direct-contact, detachable and sorptive types, are discussed from the aspects of configuration, performance and utilization. Furthermore, the studies on the economic evaluation of M-TES systems are summarized and discussed based on the analysis of the economic indicators, including initial cost, operating cost, revenue, subsidy and energy cost. Finally, the challenges and future perspectives for developing M-TES are presented. © 2018 Elsevier Ltd

  • 15.
    Lee, Duu-Jong
    et al.
    Natl Taiwan Univ Sci & Technol, Taiwan.
    Yan, Jinyue
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi. Royal Inst Technol, Stockholm, Sweden.
    Chou, Siaw-Kiang
    Natl Univ Singapore, Singapore.
    Desideri, Umberto
    Univ Perugia, Perugia, Italy.
    Clean, efficient, affordable and reliable energy for a sustainable future Preface2015Ingår i: Energy Conversion and Management, ISSN 0196-8904, E-ISSN 1879-2227, Vol. 102, s. 1-3Artikel i tidskrift (Övrigt vetenskapligt)
  • 16.
    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
    Mälardalens universitet, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    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 assessment2024Ingår i: Energy Conversion and Management, ISSN 0196-8904, E-ISSN 1879-2227, Vol. 307, artikel-id 118380Artikel i tidskrift (Refereegranskat)
    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.

  • 17.
    Li, Hailong
    et al.
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Larsson, Eva K.
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Thorin, Eva
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Dahlquist, Erik
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Yu, Xinhai
    E China Univ Sci & Technol, Shanghai, Peoples R China.
    Feasibility study on combining anaerobic digestion and biomass gasification to increase the production of biomethane2015Ingår i: Energy Conversion and Management, ISSN 0196-8904, E-ISSN 1879-2227, Vol. 100, s. 212-219Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    There is a rapid growing interest in using biomethane as fuel for transport applications. A new concept is proposed to combine anaerobic digestion and biomass gasification to produce biomethane. H-2 is separated from the syngas generated by biomass gasification in a membrane system, and then is used to upgrade raw biogas from anaerobic digestion. Simulations have been conducted based on the real operation data of one full scale biogas plant and one full scale biomass gasification plant in order to investigate the feasibility of the new concept. Results show that although less power and heat are generated compared to the gasification plant, which results in a lower overall efficiency, much more biomethane can be produced than the biogas plant; and the new concept can achieve a higher exergy efficiency. Due to the increasing price of biomethane, the novel concept demonstrates a big potential of income increase. For example, at a biomethane price of 12.74SEK/kg, the annual income can be increased by 53% compared to the total income of the biogas and gasification plant. (C) 2015 Elsevier Ltd. All rights reserved.

  • 18.
    Li, Jian
    et al.
    Tsinghua Univ, Key Lab Thermal Sci & Power Engn MOE, Key Lab CO2 Utilizat & Reduct Technol, Beijing, Peoples R China..
    Yang, Zhen
    Tsinghua Univ, Key Lab Thermal Sci & Power Engn MOE, Key Lab CO2 Utilizat & Reduct Technol, Beijing, Peoples R China..
    Li, Hailong
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi. Malardalen Univ, Sch Business Soc & Engn, Vasteras, Sweden..
    Hu, Shuozhuo
    Tsinghua Univ, Key Lab Thermal Sci & Power Engn MOE, Key Lab CO2 Utilizat & Reduct Technol, Beijing, Peoples R China..
    Duan, Yuanyuan
    Tsinghua Univ, Key Lab Thermal Sci & Power Engn MOE, Key Lab CO2 Utilizat & Reduct Technol, Beijing, Peoples R China..
    Yan, Jinyue
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi. Malardalen Univ, Sch Business Soc & Engn, Vasteras, Sweden..
    Optimal schemes and benefits of recovering waste heat from data center for district heating by CO2 transcritical heat pumps2021Ingår i: Energy Conversion and Management, ISSN 0196-8904, E-ISSN 1879-2227, Vol. 245, artikel-id 114591Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Recovering waste heat from data center (DC) for district heating by CO2 transcritical heat pumps can effectively improve the performance of DC and reduce CO2 emission of district heating. However, the optimal design schemes, financial and environmental benefits, and market competitiveness of waste heat heating system are still unclear for different application scenarios. To realize the optimal system design and evaluate the benefits at different application scenarios, this work analyzed and compared the comprehensive performance of four system design schemes, considering two waste heat recovery locations and two cycle types. The maximum coefficient of performance (COP) was set as the optimization goal. Influences of electricity and heat prices on the optimal scheme and thermo-economic performance of waste heat heating system were analyzed. The direct electric-heating, coal-heating, gas-heating, air source heat pump, and ground source heat pump were selected as the comparative heating methods to evaluate the market competitiveness of waste heat heating system. Results show that using waste heat of cooling water from IT room achieves a better thermo-economic performance than that from chillers, which increases maximum COP by 18.2%-28.9% and reduces system investment cost by 4.2%-10.2%. The COP of IHE cycle (e.g., add an internal heat exchanger in the simple cycle) is larger, whereas the simple cycle has a lower investment cost. The cycle type with the shortest dynamic payback period depends on actual electricity and heat prices. The financial and environmental benefits of waste heat heating system are very attractive since it can reduce energy cost by 23.0%-75.0% compared with common heating methods and reduce CO2 emission by 12,880 tons annually compared with gas-heating. Furthermore, the energy efficiency of DC will be improved by waste heat reuse, and the annual energy reuse effectiveness (ERE) can decrease from 1.296 to 0.902 at the annual heating time of 121 days.

  • 19.
    Liu, L.
    et al.
    Shandong University, Jinan, China.
    Sun, Q.
    Shandong University, Jinan, China.
    Li, Hailong
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Yin, H.
    Shandong University, Jinan, China.
    Ren, X.
    Shandong University, Jinan, China.
    Wennersten, R.
    Shandong University, Jinan, China.
    Evaluating the benefits of Integrating Floating Photovoltaic and Pumped Storage Power System2019Ingår i: Energy Conversion and Management, ISSN 0196-8904, E-ISSN 1879-2227, Vol. 194, s. 173-185Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Floating Photovoltaic systems have developed very fast in recent years. Compared to individual Floating Photovoltaic systems, further advantages, such as grid connectivity and energy storage, can be obtained when Floating Photovoltaic operates collaboratively with Pumped Storage Power Systems. This paper proposed an Integrated Floating Photovoltaic-Pumped Storage Power System and quantitatively assessed the potential of the integrated system in electricity generation and conservation of water and land resource. The study developed a coordinated operation model for the Integrated Floating Photovoltaic-Pumped Storage Power System, which employed a dual-objective optimization, namely to maximize the benefits of electricity generation and to minimize the energy imbalance at the same time. The dual-objective optimization was solved using the genetic algorithm method. Other benefits of the Integrated Floating Photovoltaic-Pumped Storage Power System, namely conservation of water and land resource, were also assessed. The proposed methodology was applied to a 2 GW Floating Photovoltaic farm and a 1 GW Pumped Storage Power System. Results indicated that the Integrated Floating Photovoltaic-Pumped Storage Power System has a great potential for gaining the benefits of electricity generation (9112.74 MWh in a typical sunny day averagely) and reducing energy imbalance (23.06 MW aggregately in one day). The coordinated operation provides the possibility to achieve a higher generation benefits without affecting the reliability of the grid, while the optimization method plays a key role of efficient coordination. In addition, the system would help to save 20.16 km 2 land and 19.06 million m 3 water a year due to the reduction in evaporation loss. The synthetic benefits greatly improve the economic and environmental feasibility of photovoltaic systems in reality.

  • 20.
    Liu, Shengchun
    et al.
    Tianjin University of Commerce, China.
    Wu, Sicheng
    Tianjin University of Commerce, China.
    Hu, Yukun
    University College London, UK.
    Li, Hailong
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Comparative analysis of air and CO2 as working fluids for compressed and liquefied gas energy storage technologies2019Ingår i: Energy Conversion and Management, ISSN 0196-8904, E-ISSN 1879-2227, Vol. feb, s. 608-620Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    With the large-scale use of intermittent renewable energy worldwide, such as wind energy and solar energy, energy storage systems are urgently needed and have been rapidly developed. Technologies of compressed gas energy storage (CGES) and liquefied gas energy storage (LGES) are playing an important role, and air has been commonly used as working fluid. CO2 is another potential working fluid and attracting more and more attention due to the rise of CO2 capture and utilization. However, it is still unclear which is the better working fluid. This paper comparatively analyzed the performance of CGES and LGES systems using air and CO2 as working fluids. Both diabatic and adiabatic CGES are considered. Simulation results show that except diabatic CGES systems, using CO2 could achieve a similar or even higher round-trip efficiency than using air. In addition, the use of CO2 instead of air as a working fluid has additional advantages, such as a lower storage temperature can be achieved at the same storage pressure for the adiabatic CGES system; and a higher condensing temperature can be achieved at the same condensing pressure for the LGES system, which can benefit the system design and operation.

  • 21.
    Liu, Z.
    et al.
    Qingdao Univ Sci & Technol, Peoples R China.
    Yang, X.
    Qingdao Univ Sci & Technol, Peoples R China.
    Jia, W.
    Qingdao Univ Sci & Technol, Peoples R China.
    Li, Hailong
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Hooman, K.
    Univ Queensland, Australia.
    Thermodynamic study on a combined heat and compressed air energy storage system with a dual-pressure organic Rankine cycle2020Ingår i: Energy Conversion and Management, ISSN 0196-8904, E-ISSN 1879-2227, Vol. 221, artikel-id 113141Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Compressed air energy storage (CAES) is a promising energy storage and supply technology. It has attracted attention due to its reliability, economic feasibility, longer operating lifetime and lower environmental effects compared to available storage technologies. A novel hybrid energy storage system, termed as CH-CAES-dORC, is proposed. It includes an advanced CAES, an electrical heater (EH) and a dual-pressure organic Rankine cycle (dORC). Our analysis demonstrate that integrating an dORC bottoming cycle for improving the round trip efficiency of the CH-CAES system is superior to a system relying on single-pressure ORC (sORC) system. Parametric analysis is carried out to study the effects of several key parameters on the system performance. The results indicate that the improvement of the CH-CAES round trip efficiency by means of integrating ORC bottoming cycles decreases with a higher charging pressure, and increases with a larger charge-discharge pressure ratio and a higher electrical heating temperature. The superiority of the CH-CAES-dORC, compared to the CH-CAES-sORC, is more pronounced at higher electrical heating temperature. There is always a peak round trip efficiency for the CH-CAES-dORC system with an increase in hot end temperature of low temperature evaporator under different hot end temperatures of high temperature evaporator. In other words, the dORC is a more favorable bottoming cycle for application of the CH-CAES waste heat compared with the sORC. © 2020 Elsevier Ltd

  • 22.
    Lyu, Yuexia
    et al.
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi. School of Mechanical & Automotive Engineering, Qilu University of Technology (Shandong Academy of Sciences), Jinan, 250353, China.
    Xia, L.
    School of Energy, Power and Mechanical Engineering, North China Electric Power University, Beijing, China.
    Li, M.
    School of Mechanical & Automotive Engineering, Qilu University of Technology (Shandong Academy of Sciences), Jinan, China.
    Wang, L.
    China Society, BeiCoal jing, China.
    Su, Y.
    School of Mechanical & Automotive Engineering, Qilu University of Technology (Shandong Academy of Sciences), Jinan, China.
    Yan, Jinyue
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Techno-economic evaluation of an optical fiber based hybrid solar lighting system2020Ingår i: Energy Conversion and Management, ISSN 0196-8904, E-ISSN 1879-2227, Vol. 225, artikel-id 113399Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Optical fiber solar lighting systems are an appealing approach for illumination applications with the aim of reducing energy consumption and greenhouse gas emissions from artificial lighting. This study presented the design, construction and assessment of an optical fiber based hybrid solar lighting system for illumination of interior spaces. The proposed system combines the features of optical fiber daylighting technology and photovoltaic power generation technology. Specifically, a secondary light concentrator was designed to improve the uniformity of flux distribution and solve the overheating problem of PMMA fibers. The technical feasibility of the hybrid solar lighting system was validated using the fabricated prototype in a 5 m2 darkroom during a whole day test. Experimental results showed that, an average illuminance of 105 lx at a distance of 2 m from the end of optical fiber bundle was achieved, saving 316.82 kWh and reducing 251.24 kg carbon dioxide emissions every year in the studied case. Finally, cost analysis of the proposed hybrid solar lighting system was carried out and compared with three conventional lighting systems. The total payback period of the hybrid solar lighting system was 3.7 years and further reduced to 1.7 years in mass production. In the studied case, the hybrid solar lighting system was economically competitive after 2 years and 12 years of operation in comparison with a 100 W incandescent bulb lighting system and a 30 W T8 fluorescent lamp lighting system, respectively.

  • 23.
    Maher, Azaza
    et al.
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Eriksson, Douglas
    Mälardalens Högskola.
    Wallin, Fredrik
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    A study on the viability of an on-site combined heat- and power supply system with and without electricity storage for office building2020Ingår i: Energy Conversion and Management, ISSN 0196-8904, E-ISSN 1879-2227, Vol. 213, artikel-id 112807Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The building sector in the European Union accounts for over 40% of the final energy use, where the usage of non-residential buildings may be up to 40% higher than the residential sector. Improving building energy efficiency across all categories of buildings is one key goal of the European energy policies, made prominent by the Climate and Energy package, Energy Performance of Building Directive and Energy Efficiency Directive. In this study, the profitability of an on-site combined heat and power supply system for an office building is investigated. A reference model utilizing solely district heating was constructed and used for validation purposes. Then, a photovoltaic assisted ground source heat pump model was developed and investigated with and without electrical storage to reveal the most cost-effective investment scenario in cold climate regions. The reference model was validated using consumption data provided by the facility owner, after which an investigation of the energy saving potential along with the economic viability of adapting a new heat- and power supply system was conducted. It was concluded that a ground source heat pump in combination with a standalone rooftop photovoltaic system, was successful in satisfying thermal requirements while lowering the building specific energy demand compared to utilizing a district heating system. The photovoltaic assisted ground source heat pump system including a battery bank is the most profitable when incentives are granted, a higher self-consumption of 93.1% is achieved with a battery capacity of 38.4 kWh. 

  • 24.
    Mirmoshtaghi, Guilnaz
    et al.
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Skvaril, Jan
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Campana, Pietro Elia
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Li, Hailong
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Thorin, Eva
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Dahlquist, Erik
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    The influence of different parameters on biomass gasification in circulating fluidized bed gasifiers2016Ingår i: Energy Conversion and Management, ISSN 0196-8904, E-ISSN 1879-2227, Vol. 126, s. 110-123Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The mechanism of biomass gasification has been studied for decades. However, for circulating fluidized bed (CFB) gasifiers, the impacts of different parameters on the gas quality and gasifiers performance have still not been fully investigated. In this paper, different CFB gasifiers have been analyzed by multivariate analysis statistical tools to identify the hidden interrelation between operating parameters and product gas quality, the most influencing input parameters and the optimum points for operation. The results show that equivalence ratio (ER), bed material, temperature, particle size and carbon content of the biomass are the input parameters influencing the output of the gasifier the most. Investigating among the input parameters with opposite impact on product gas quality, cases with optimal gas quality can result in high tar yield and low carbon conversion while low tar yield and high carbon conversion can result in product gas with low quality. However using Olivine as the bed material and setting ER value around 0.3, steam to biomass ratio to 0.7 and using biomass with 3 mm particle size and 9 wt% moisture content can result in optimal product gas with low tar yield.

  • 25.
    Olsson, Alexander
    et al.
    KTH Royal Inst Technology, Stockholm, Sweden.
    Campana, Pietro Elia
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Lind, Marten
    ZeroMission, Stockholm, Sweden.
    Yan, Jinyue
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    PV water pumping for carbon sequestration in dry land agriculture2015Ingår i: Energy Conversion and Management, ISSN 0196-8904, E-ISSN 1879-2227, Vol. 102, s. 169-179Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    This paper suggests a novel model for analysing carbon sequestration activities in dry land agriculture considering the water-food-energy-climate nexus. The paper is based on our on-going studies on photovoltaic water pumping (PVWP) systems for irrigation of grasslands in China. Two carbon sequestration projects are analysed in terms of their water productivity and carbon sequestration potential. It is concluded that the economic water productivity, i.e. how much water that is needed to produce an amount of grass, of grassland restoration is low and that there is a need to include several of the other co-benefits to justify the use of water for climate change mitigation. The co-benefits are illustrated in a nexus model including (1) climate change mitigation, (2) water availability, (3) downstream water impact, (4) energy security, (5) food security and (6) moisture recycling. We argue for a broad approach when analysing water for carbon sequestration. The model includes energy security and food security together with local and global water concerns. This makes analyses of dry land carbon sequestration activities more relevant and accurate. Without the nexus approach, the co-benefits of grassland restoration tend to be diminished. 

  • 26.
    Qi, Lingfei
    et al.
    School of Mechanical Engineering, Southwest Jiaotong University, Chengdu, 610031, China.
    Jiang, Mingkun
    Key Laboratory of Pressure Systems and Safety (MOE), School of Mechanical and Power Engineering, East China University of Science and Technology, Shanghai, 200237, China.
    Lv, Yuexia
    School of Mechanical & Automotive Engineering, Qilu University of Technology (Shandong Academy of Sciences), Jinan, 250353, China.
    Zhang, Z.
    School of Mechanical Engineering, Southwest Jiaotong University, Chengdu, 610031, China.
    Yan, Jinyue
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Techno-economic assessment of photovoltaic power generation mounted on cooling towers2021Ingår i: Energy Conversion and Management, ISSN 0196-8904, E-ISSN 1879-2227, Vol. 235, artikel-id 113907Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The deployment of photovoltaic systems based on existing buildings has been the focus of research in recent years. It is necessary to evaluate the techno-economic performance of the new photovoltaic system deployment strategy for its actual implementation. In this paper, we comprehensively evaluated the power generation potential and economic performance of photovoltaics deployed on hyperbolic cooling towers in Mainland China. Based on the local solar radiation situations and electricity prices, we analyzed both the technical and economic performance of cooling towers photovoltaic (CT-PV) located in different cities. The results show that the total capacity of photovoltaic installations on all cooling towers reaches 1.05 GW, with corresponding annual power generation of 1.44 TWh. The total CO2 emission reduction and total profit by CT-PV cooling towers photovoltaic over a lifetime of 25 years can reach 31 Mts and 8.00 billion CNY, respectively. The return on investment is between 1.1 and 2.49, depending on the location. The payback period for all cities is less than 8 years, and around 90% of the cities’ solar generation electricity prices are below 0.35 CNY/kWh, which can compete with the benchmark price of coal-fired electricity. These results reveal that CT-PVs cooling towers photovoltaics have significant potential for PV photovoltaic application with attractive energy and economic benefits.

  • 27.
    Qi, Lingfei
    et al.
    Southwest Jiaotong Univ, Sch Mech Engn, Chengdu, Peoples R China.;Mälardalen Univ, Sch Business Soc & Energy, SE-72123 Västerås, Sweden..
    Jiang, Mingkun
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi. Key Lab Pressure Syst & Safety MOE, Shanghai 200237, Peoples R China..
    Lyu, Yuexia
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi. Qilu Univ Technol, Sch Mech & Automot Engn, Shandong Acad Sci, Jinan 250353, Peoples R China..
    Yan, Jinyue
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    A celestial motion-based solar photovoltaics installed on a cooling tower2020Ingår i: Energy Conversion and Management, ISSN 0196-8904, E-ISSN 1879-2227, Vol. 216, artikel-id 112957Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Traditional photovoltaic systems are facing two major problems, including occupying excessive land resources and causing power loss due to long-distance power transmission. In this paper, we investigate an adaptive celestial motion-based solar photovoltaics, which is installed on the cooling tower of a thermal power plant. The proposed solar photovoltaics can rotate around its own axis and revolve around the cooling tower, which enables the solar panels to be always perpendicular to the solar rays based on the rotation and revolution of the earth. In order to estimate the technical and economic performance of the solar photovoltaics, three thermal power plants located in Wujing, Datong, and Hami in China are selected for a case study. Comparative analysis is conducted under four different photovoltaic configurations of fixed angle, adjustable azimuth, adjustable tilt, and adjustable azimuth and tilt of solar panels. Analysis and estimation results show that the capacities of photovoltaic installations reach 1.76 MW, 3.51 MW, and 1.82 MW, with corresponding annual power generation of 2.13 GWh, 6.00 GWh, and 3.94 GWh in Wujing, Datong, and Hami, respectively. The total profits are 27.9 million CNY, 60.7 million CNY, and 36.0 million CNY, with the return on investment of 240%, 261%, and 300%, respectively. Based on solar radiation, local electricity price, and cooling tower area, the payback period for PVs of the three studied power plants is about 6 years. The high energy and economic benefits indicate that the proposed photovoltaics has a good prospect for being considered as an auxiliary power generation system in thermal power plant.

  • 28.
    Quitoras, M. R.
    et al.
    University of Victoria, Victoria, Canada.
    Cabrera, P.
    University of Las Palmas de Gran Canaria, Canary Islands, Spain.
    Campana, Pietro Elia
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Rowley, P.
    Loughborough University, UK.
    Crawford, C.
    University of Victoria, Victoria, Canada.
    Towards robust investment decisions and policies in integrated energy systems planning: Evaluating trade-offs and risk hedging strategies for remote communities2021Ingår i: Energy Conversion and Management, ISSN 0196-8904, E-ISSN 1879-2227, Vol. 229, artikel-id 113748Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Policy and investment decisions in developing clean energy strategies for remote communities are subject to multiple uncertainties that impact overall strategy outcomes, including those related to environmental emissions and energy costs. In this context, robust modeling approaches are required that can clarify potential outcomes while subject to such uncertainties. This work introduces a novel modeling framework that enables enhanced decision making in energy systems planning for remote communities, which for the first time takes into account context-specific decision-maker attitudes towards multiple inter-related uncertainties and various energy solution philosophies. In particular, multiple energy system configurations are evaluated by simultaneously minimizing the levelised cost of energy and fuel consumption, with a test case for a specific community in the Northwest Territories, Canada. The concept of model robustness and validity together with the stochastic nature of uncertain parameters are combined in a multi-objective optimization framework that elucidates the full spectrum of energy solutions available in such a remote Arctic context. Introducing known uncertainties in renewable energy characteristics was found to reduce overall energy yields from the renewable energy technologies. Specifically, the deterministic renewable energy penetration of 69% from a specific energy system configuration reduced to a mean of 51% after the inclusion of uncertainties via probabilistic simulation. Conversely, diesel fuel consumption increased to 750,000 L/yr (mean) from its initial deterministic value of 447,470 L/yr. Holistic energy solutions which include both supply and demand-side considerations are also analyzed. Specifically, a reduced community domestic heating load of 40% was achieved via retrofit of high performance building fabric enclosures evaluated in conjunction with renewable energy supply options. Ultimately, insights and real-world applications have been synthesized to provide coherent recommendations on strategies to address energy security, energy affordability and environmental sustainability, along with meaningful propositions towards Indigenous community-led energy projects in a range of contexts.

  • 29.
    Quitoras, M. R.
    et al.
    University of Victoria, Victoria, Canada.
    Campana, Pietro Elia
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Crawford, C.
    University of Victoria, Victoria, Canada.
    Exploring electricity generation alternatives for Canadian Arctic communities using a multi-objective genetic algorithm approach2020Ingår i: Energy Conversion and Management, ISSN 0196-8904, E-ISSN 1879-2227, Vol. 210, artikel-id 112471Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Indigenous peoples in the Northern communities of Canada are experiencing some of the worst catastrophic effects of climate change, given the Arctic region is warming twice as fast as the rest of the world. Paradoxically, this increasing temperature can be attributed to fossil fuel-based power generation on which the North is almost totally reliant. At the moment, diesel is the primary source of electricity for majority of Arctic communities. In addition to greenhouse gas and other airborne pollutants, this situation exposes risk of oil spills during fuel transport and storage. Moreover, shipping fuel is expensive and ice roads are harder to maintain as temperatures rise. As a result, Northern governments are burdened by rising fuel prices and increased supply volatility. In an effort to reduce diesel dependence, the multi-objective microgrid optimization model was built in this work to handle the complex trade-offs of designing energy system for an Arctic environment and other remote communities. The tool uses a genetic algorithm to simultaneously minimize levelised cost of energy and fuel consumption of the microgrid system through dynamic simulations. Component submodel simulation results were validated against an industry and academic accepted energy modeling tool. Compared to previous energy modeling platforms, proposed method is novel in considering Pareto front trade-offs between conflicting design objectives to better support practitioners and policy makers. The functionality of the method was demonstrated with a case study on Sachs Harbour, in the Northernmost region of the Northwest Territories. The algorithm selected a fully hybrid wind-solar-battery-diesel system as the most suited technically, economically and environmentally for the community. The robustness of the results was assessed by performing system failure analysis of the model results. Overall, the modeling framework can help decision makers in identifying trade-offs in energy policy to transition the Canadian Arctic and other remote communities towards more sustainable and clean sources of energy.

  • 30.
    Salman, Chaudhary Awais
    et al.
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Naqvi, Muhammad
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Thorin, Eva
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Yan, Jinyue
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Impact of retrofitting existing combined heat and power plant with polygeneration of biomethane: A comparative techno-economic analysis of integrating different gasifiers2017Ingår i: Energy Conversion and Management, ISSN 0196-8904, E-ISSN 1879-2227, Vol. 152, s. 250-265Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    It is vital to identify and evaluate the optimal gasifier configuration that could be integrated with existing or new combined heat and power (CHP) plants to maximize the utilization of boiler operating capacity during off-peak hours with minimal effect on the boiler performance. This study aims to identify technically and economically most suitable gasification configuration and the reasonable operational limits of a CHP plant when integrated with different types of gasifiers. The selected gasifiers for the study are, (i) indirectly heated dual fluidized bed gasifier (DFBG), (ii) directly heated circulating fluidized bed gasifier (CFBG), and (iii) entrained flow gasifier (EFG). The gasifiers are selected on their ability to produce high-quality syngas from waste refused derived fuel (RDF). The syngas from the gasifiers is utilized to produce biomethane, whereas the heat and power from the CHP plant are consumed to run the gasification process. A detailed techno-economic analysis is performed using both flexible capacity and fixed capacity gasifiers and integrated with the CHP plant at full load. The results reveal that the integration leads to increase in operating time of the boiler for all gasifier configurations. The indirectly heated DFBG shows the largest biomethane production with less impact on the district heat and power production. Extra heat is available for biomethane production when the district heat and biomethane are prioritized, and the electric power is considered as a secondary product. Furthermore, the economic indicators reflect considerable dependency of integrated gasification performance on variable prices of waste biomass and biomethane. 

  • 31.
    Salman, Chaudhary Awais
    et al.
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Thorin, Eva
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Yan, Jinyue
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Opportunities and limitations for existing CHP plants to integrate polygeneration of drop-in biofuels with onsite hydrogen production2020Ingår i: Energy Conversion and Management, ISSN 0196-8904, E-ISSN 1879-2227, Vol. 221, artikel-id 113109Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Over the past few years, there has been increasing research interest in retrofitting existing combined heat and power (CHP) plants with new technologies to co-produce other products. The focus has been on the design of fixed-sized processes for integration into CHP plants without affecting their performance. The primary objective of this study was to test the limits of a CHP plant with respect to retrofitting flexible thermochemical conversion of waste to drop-in biofuels with properties similar to petroleum fuels. Waste conversion to drop-in biofuels also requires significant amount of hydrogen for drop-in biofuels synthesis — Required hydrogen was also produced onsite in thermochemical processes integrated with CHP plant. The secondary objective was to determine the maximum number of days a flexible retrofitted waste-thermochemical process can run annually using only excess heat from a CHP plant, and whether such processes are profitable when operating flexibly. The results show that the selection of heat extraction points for the utilization of excess heat from the CHP plant for energy-intensive processes is critical for maintaining the flexibility of the integrated thermochemical processes. Thermochemical processes integrated with CHP plants were able to operate on approximately 180 days of the year by utilizing only excess heat from the CHP plant. Integration of pyrolysis showed more flexibility than integration of gasification. Onsite hydrogen production was the main limiting factor for the integration of thermochemical process with the existing CHP plant to produce drop-in biofuels. Hydrogen produced with a solid oxide electrolysis cell (SOEC) decreased the overall system efficiency and limited the capacity of the overall process. However, hydrogen production from a water gas shift (WGS) reactor was more expensive. The results also indicated that small changes in the financial parameters have a large impact on the economic performance of the integrated process. 

  • 32.
    Salman, Chaudhary Awais
    et al.
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Thorin, Eva
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Yan, Jinyue
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi. School of Chemical Science and Engineering, Royal Institute of Technology, Stockholm, Sweden.
    Uncertainty and influence of input parameters and assumptions on the design and analysis of thermochemical waste conversion processes: A stochastic approach2020Ingår i: Energy Conversion and Management, ISSN 0196-8904, E-ISSN 1879-2227, Vol. 214, artikel-id 112867Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Process design is a challenging task for researchers and engineers. Incomplete information and variation in input data affect the outputs and reliability of key performance indicators (KPIs) of the designed process. The efficient utilization of waste is becoming increasingly important, and researchers use simulation and modelling tools for design and assessment of waste conversion processes. The complex nature of modelling of waste conversion processes and uncertainty of technical and financial data result in substantial variation in the KPIs of the designed process. In this study, we identified the critical parameters and assumptions that cause uncertainty in the process design analysis of waste-to-biofuels conversions. We used a stochastic modelling approach to address these methodological challenges and performed Monte Carlo simulations on waste-to-biofuel processes. The identified uncertain parameters and inputs were varied for a whole year with a one-minute time step. Different thermochemical conversion pathways were modelled by varying uncertain inputs and assumptions over the year by applying Monte Carlo simulations. Variations in the system's technical and economic KPIs were observed and compared. The results show that the heterogeneous nature of waste is a highly sensitive parameter, and a small change in its elemental analysis varies the technical performance significantly. Similarly, operating hours, plant size, capital investment, waste, and biofuel price are also very influential parameters on process design. Furthermore, the feasibility of waste-to-biofuel systems depends largely on how researchers and engineers select these parameters. Overall, the results reveal that by including the uncertainty of input parameters and assumptions in process design, the biases in results could be addressed transparently, making the overall assessment more reliable. 

  • 33.
    Shabani, Masoume
    et al.
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Dahlquist, Erik
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Wallin, Fredrik
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Yan, Jinyue
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi. KTH Royal Inst Technol, Sch Chem Sci & Engn, Stockholm, Sweden.
    Techno-economic impacts of battery performance models and control strategies on optimal design of a grid-connected PV system2021Ingår i: Energy Conversion and Management, ISSN 0196-8904, E-ISSN 1879-2227, Vol. 245, artikel-id 114617Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    A battery storage has emerged as the most widely-used storage option, due to its flexible and complementary functionality for renewable energy systems such as solar PV and wind power. In order to ensure the efficient operation of batteries in energy systems, a proper battery model is essential in predicting realistic battery performance under various operating conditions. Accurate knowledge of the state of charge, state of power, and battery efficiency is a necessity for the development of advanced grid management applications. This paper investigates the techno-economic impacts of two battery modelling scenarios on the sizing and optimization of a grid-connected PV-battery system. Scenario 1 is based on a common simple battery model and control strategy which represents the battery status without reflecting dynamic behavior. By contrast, Scenario 2 is based on a complex battery model involving estimation of battery current-voltage characteristics under various operating conditions. A rule-based operational strategy linked to a non-dominated sorting genetic algorithm is further employed for the simulation and multi-objective optimization of a grid-connected hybrid PV-battery system. The battery life cycle cost and the self-sufficiency ratio are analyzed and optimized as objective functions, and battery capacity constitutes as a decision variable. The results show that in order to reach the same self-sufficiency ratio, the optimization of a hybrid energy system based on Scenario 1 leads to solutions with a higher life cycle cost and requiring bigger battery capacity, compared to that of Scenario 2. Moreover, under the same design parameters, the system optimization based on Scenario 2 delivers more power to the end-user, which leads to a higher selfsufficiency ratio compared to when the system is simulated based on Scenario 1. This study proves that an efficient battery model with sufficient accuracy is techno-economically more beneficial, and leads to more accurate battery sizing.

  • 34.
    Starfelt, Fredrik
    et al.
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Tomas Aparicio, Elena
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Li, Hailong
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Dotzauer, Erik
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Integration of torrefaction in CHP plants - A case study2015Ingår i: Energy Conversion and Management, ISSN 0196-8904, E-ISSN 1879-2227, Vol. 90, s. 427-435Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Torrefied biomass shows characteristics that resemble those of coal. Therefore, torrefied biomass can be co-combusted with coal in existing coal mills and burners. This paper presents simulation results of a case study where a torrefaction reactor was integrated in an existing combined heat and power plant and sized to replace 25%, 50%, 75% or 100% of the fossil coal in one of the boilers. The simulations show that a torrefaction reactor can be integrated with existing plants without compromising heat or electricity production. Economic and sensitivity analysis show that the additional cost for integrating a torrefaction reactor is low which means that with an emission allowance cost of 37 €/ton CO2, the proposed integrated system can be profitable and use 100% renewable fuels. The development of subsidies will affect the process economy. The determinant parameters are electricity and fuel prices.

  • 35.
    Sun, Yingying
    et al.
    Tianjin Univ Commerce, Tianjin, Peoples R China..
    Dong, Beibei
    Mälardalens universitet, Akademin för ekonomi, samhälle och teknik, Framtidens energi. Tianjin Univ Commerce, Tianjin, Peoples R China..
    Wang, Liang
    SINTEF Energy Res, Trondheim, Norway..
    Li, Hailong
    Mälardalens universitet, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Thorin, Eva
    Mälardalens universitet, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Technology selection for capturing CO2 from wood pyrolysis2022Ingår i: Energy Conversion and Management, ISSN 0196-8904, E-ISSN 1879-2227, Vol. 266, artikel-id 115835Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Emerging negative emission technologies (NETs) are considered as effective measures to reduce carbon dioxide emissions to achieve the climate goal set by the Paris Agreement, and bioenergy with carbon capture and storage (BECCS) is one of the most important NETs. Integrating CO2 capture with biomass pyrolysis (PyrCC) is attracting increasing interest, because biomass pyrolysis has been widely used to produce biooil to replace fossil fuel for decarbonizing the transport sector. In order to provide guidance to the selection of CO2 capture technologies, this paper evaluated the technical and economic performances of PyrCC when different CO2 capture technologies are integrated, including monoethanolamine-based chemical absorption (MEA-CA), temperature swing absorption (TSA), calcium looping (CaL), and chemical looping combustion (CLC). Generally speaking, CLC can realize the highest capture amount of CO2 with the lowest energy penalty. Meanwhile, CLC and CaL show the lowest levelized cost of CO2 (LCOC), which are around 56$/tCO(2); and on the contrary MEA-CA shows the highest one of 83 $/tCO(2). In addition, the key process parameter of pyrolysis, reaction time, has clear effects on the performance of CO2 capture as the longer reaction time leads to an increased amount of captured CO2 and reduced energy penalty. As a result, when the reaction time increases, the LCOCs of all assessed technologies decrease. Moreover, the net present value and the payback time are also estimated for different technologies. At the carbon price of 70.1$/tCO(2), MEA-CA and CLC show the longest and shortest payback time that are 5.9 years and 3.2 years respectively.

  • 36.
    Tan, Y.
    et al.
    Royal Institute of Technology, Stockholm, Sweden.
    Nookuea, Worrada
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Li, Hailong
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Thorin, Eva
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Yan, Jinyue
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Property impacts on Carbon Capture and Storage (CCS) processes: A review2016Ingår i: Energy Conversion and Management, ISSN 0196-8904, E-ISSN 1879-2227, Vol. 118, s. 204-222Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The knowledge of thermodynamic and transport properties of CO2-mixtures is important for designing and operating different processes in carbon capture and storage systems. A literature survey was conducted to review the impact of uncertainty in thermos-physical properties on the design and operation of components and processes involved in CO2 capture, conditioning, transport and storage. According to the existing studies on property impacts, liquid phase viscosity and diffusivity as well as gas phase diffusivity significantly impact the process simulation and absorber design for chemical absorption. Moreover, the phase equilibrium is important for regenerating energy estimation. For CO2 compression and pumping processes, thermos-physical properties have more obvious impacts on pumps than on compressors. Heat capacity, density, enthalpy and entropy are the most important properties in the pumping process, whereas the compression process is more sensitive to heat capacity and compressibility. In the condensation and liquefaction process, the impacts of density, enthalpy and entropy are low on heat exchangers. For the transport process, existing studies mainly focused on property impacts on the performance of pipeline steady flow processes. Among the properties, density and heat capacity are most important. In the storage process, density and viscosity have received the most attention in property impact studies and were regarded as the most important properties in terms of storage capacity and enhanced oil recovery rate. However, for physical absorption, physical adsorption and membrane separation, there has been a knowledge gap about the property impact. In addition, due to the lack of experimental data and process complexity, little information is available about the influence of liquid phase properties on the design of the absorber and desorber for chemical absorption process. In the CO2 conditioning process, knowledge of the impacts of properties beyond density and enthalpy is insufficient. In the transport process, greater attention should focus on property impacts on transient transport processes and ship transport systems. In the storage process, additional research is required on the dispersion process in enhanced oil recovery and the dissolution process in ocean and saline aquifer storage.

  • 37.
    Tao, J.
    et al.
    North China Electric Power University, Beijing, China.
    Lu, Q.
    North China Electric Power University, Beijing, China.
    Dong, C.
    North China Electric Power University, Beijing, China.
    Du, X.
    North China Electric Power University, Beijing, China.
    Dahlquist, Erik
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Effects of electric current upon catalytic steam reforming of biomass gasification tar model compounds to syngas2015Ingår i: Energy Conversion and Management, ISSN 0196-8904, E-ISSN 1879-2227, Vol. 100, s. 56-63Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Electrochemical catalytic reforming (ECR) technique, known as electric current enhanced catalytic reforming technique, was proposed to convert the biomass gasification tar into syngas. In this study, Ni-CeO<inf>2</inf>/γ-Al<inf>2</inf>O<inf>3</inf> catalyst was prepared, and toluene was employed as the major feedstock for ECR experiments using a fixed-bed lab-scale setup where thermal electrons could be generated and provided to the catalyst. Several factors, including the electric current intensity, reaction temperature and steam/carbon (S/C) ratio, were investigated to reveal their effects on the conversion of toluene as well as the composition of the gas products. Moreover, toluene, two other tar model compounds (benzene and 1-methylnaphthalene) and real tar (tar-containing wastewater) were subjected to the long period catalytic stability tests. All the used catalysts were analyzed to determine their carbon contents. The results indicated that the presence of electric current enhanced the catalytic performance remarkably. The toluene conversion reached 99.9% under the electric current of 4 A, catalytic temperature of 800 °C and S/C ratio of 3. Stable conversion performances of benzene, 1-methylnaphthalene and tar-containing wastewater were also observed in the ECR process. H<inf>2</inf> and CO were the major gas products, while CO<inf>2</inf> and CH<inf>4</inf> were the minor ones. Due to the promising capability, the ECR technique deserves further investigation and application for efficient tar conversion.

  • 38.
    Wang, F.
    et al.
    Tianjin University, Ministry of Education of China, Tianjin, China.
    Li, Hailong
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Zhao, J.
    Tianjin University, Ministry of Education of China, Tianjin, China.
    Deng, S.
    Tianjin University, Ministry of Education of China, Tianjin, China.
    Yan, Jinyue
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi. Royal Institute of Technology, Stockholm, Sweden.
    Technical and economic analysis of integrating low-medium temperature solar energy into power plant2016Ingår i: Energy Conversion and Management, ISSN 0196-8904, E-ISSN 1879-2227, Vol. 112, s. 459-469Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    In order to mitigate CO2 emission and improve the efficiency of the utilization of solar thermal energy (STE), solar thermal energy is proposed to be integrated into a power plant. In this paper, seven configurations were studied regarding the integration of STE. A 300 MWe subcritical coal-fired plant was selected as the reference, chemical absorption using monoethanolamine solvent was employed for CO2 capture, and parabolic trough collectors and evacuated tube collectors were used for STE collection. Both technical analysis and economic evaluation were conducted. Results show that integrating solar energy with post-combustion CO2 capture can effectively increase power generation and reduce the electrical efficiency penalty caused by CO2 capture. Among the different configurations, Config-2 and Config-6, which use medium temperature STE to replace high pressure feedwater without and with CO2 capture, show the highest net incremental solar efficiency. When building new plants, integrating solar energy can effectively reduce the levelized cost of electricity (LCOE). The lowest LCOE, 99.28 USD/MWh, results from Config-6, with a parabolic trough collector price of 185 USD/m2. When retrofitting existing power plants, Config-6 also shows the highest net present value (NPV), while Config-2 has the shortest payback time at a carbon tax of 50 USD/ton CO2. In addition, both LCOE and NPV/payback time are clearly affected by the relative solar load fraction, the price of solar thermal collectors and the carbon tax. Comparatively, the carbon tax can affect the configurations with CO2 capture more clearly than those without CO2 capture. 

  • 39.
    Wang, T.
    et al.
    Key Laboratory of Pressure Systems and Safety (MOE), School of Mechanical and Power Engineering, East China University of Science and Technology, Shanghai, China.
    Luan, W.
    Key Laboratory of Pressure Systems and Safety (MOE), School of Mechanical and Power Engineering, East China University of Science and Technology, Shanghai, China.
    Liu, T.
    Key Laboratory of Pressure Systems and Safety (MOE), School of Mechanical and Power Engineering, East China University of Science and Technology, Shanghai, China.
    Tu, S. -T
    Key Laboratory of Pressure Systems and Safety (MOE), School of Mechanical and Power Engineering, East China University of Science and Technology, Shanghai, China.
    Yan, Jinyue
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi. School of Chemical Science, KTH Royal Institute of Technology, Stockholm, Sweden.
    Performance enhancement of thermoelectric waste heat recovery system by using metal foam inserts2016Ingår i: Energy Conversion and Management, ISSN 0196-8904, E-ISSN 1879-2227, Vol. 124, nr September, s. 13-19Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    This paper proposed a type of metal foams filled thermoelectric generator (TEG) for waste heat recovery. Metal foam inserts of three kinds of pore densities (5 PPI, 10 PPI and 20 PPI) were included, considering the heat transfer enhancing features of porous metal mediums. A flow channel detachable prototype was designed to experimentally investigate the influence of metal foams on the performance of thermoelectric waste heat recovery (TWHR) system. The operating parameters were further experimented to improve the thermoelectric power generation efficiency, including hot air inlet temperature, cold water flow rate, metal foam pore density and thermoelectric module (TEM) connecting mode. Moreover, the TWHR performance of the system was evaluated on power generation efficiency, heat exchange effectiveness and waste heat recovery rate, respectively. The results showed that filling metal foams in the flow channels could effectively enhance the performance of the TWHR system. The maximum power generation efficiency was 2.05%, when the TEG was filled with 5 PPI metal foams. It was 29.75% higher than the value of unfilled TEG.

  • 40.
    Wang, W.
    et al.
    School of Engineering, Sun Yat-sen University, Guangzhou, China.
    He, S.
    Academy of Building Energy Efficiency of Guangzhou University, Guangzhou, China.
    Guo, S.
    Inner Mongolia University of Science and Technology, Baotou, China.
    Yan, Jinyue
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Ding, J.
    School of Engineering, Sun Yat-sen University, Guangzhou, China.
    A combined experimental and simulation study on charging process of Erythritol-HTO direct-blending based energy storage system2014Ingår i: Energy Conversion and Management, ISSN 0196-8904, E-ISSN 1879-2227, Vol. 83, s. 306-313Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Thermal energy storage (TES) system is essential to recover and use intermittent heat, such as industrial waste/excess heat or solar energy. In this paper, a direct-contact erythritol/heat transfer oil (HTO) energy storage system has been studied experimentally, consisting of a thermal energy storage unit, electrical heaters, heat exchanger and water cycle. In the system, erythritol has been used as an energy storage media (melting point = 118 °C, heat enthalpy = 330 kJ/kg), and HTO is used as a heat transfer material. Moreover, simulation has been conducted to understand heat transfer enhancement mechanisms of direct-contact heat storage. It is noticed that, at the beginning of heat storage, heat transfer oil has a small flow rate due to the block of solid part. PCM in the middle area of the storage unit melts faster than other parts due to the greater heat transfer on the liquid-solid interface of the both sides, and erythritol attached on the storage unit wall melts slowly since small heat conductivity plays a key role for heat transfer. It is also found that increasing the flow rate of HTO can significantly decrease the melting time by increasing fluid turbulent degree. 

  • 41.
    Xu, B.
    et al.
    Northwest A&F Univ, Key Lab Agr Soil & Water Engn Arid & Semiarid Are, Minist Educ, Yangling, Shaanxi, Peoples R China; ‎ Northwest A&F Univ, Inst Water Resources & Hydropower Res, Yangling, Shaanxi, Peoples R China.
    Li, H.H
    Northwest A&F Univ, Key Lab Agr Soil & Water Engn Arid & Semiarid Are, Minist Educ, Yangling, Shaanxi, Peoples R China; ‎ Northwest A&F Univ, Inst Water Resources & Hydropower Res, Yangling, Shaanxi, Peoples R China.
    Campana, Pietro Elia
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Hredzak, B.
    Univ New South Wales, Sch Elect Engn & Telecommun, Sydney, Australia.
    Chen, D.Y
    Northwest A&F Univ, Key Lab Agr Soil & Water Engn Arid & Semiarid Are, Minist Educ, Yangling, Shaanxi, Peoples R China; ‎ Northwest A&F Univ, Inst Water Resources & Hydropower Res, Yangling, Shaanxi, Peoples R China.
    Dynamic regulation reliability of a pumped-storage power generating system: Effects of wind power injection2020Ingår i: Energy Conversion and Management, ISSN 0196-8904, E-ISSN 1879-2227, Vol. 222, artikel-id 113226Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Multi-energy integrated sources are increasingly being used as the bundling-sale for electric systems. Estimating the power supply reliability and regulation performance of the fixed-speed Pumped-Storage Generation Systems (PSGSs) in suppressing power fluctuations of intermittent energy is essential to the operational safety and reliability of a system. However, the regulation process relates to the coupling fluctuations of hydraulic-mechanical-electrical factors, leading to a multiple time-scale effect to the whole hybrid power system. This makes the PSGS's power response lagging behind the wind power fluctuation and further impacts the power supply reliability of the hybrid power system. To enable the analysis, a numerical model which describes operating states of the presented integrated system, including wind energy and PSGS, is developed in MATLAB/Simulink. Then, ten wind scenarios are selected to study complementation and regulation ability of the PSGS based on a framework of evaluation indicators. The results show that longer power response delay and larger guide vane distance opening result in weaker complementary response of PSGS to wind disturbances. It is also shown that the PSGS provides good complementary capability at lower random wind standard deviation (0.5 vs 1.5), larger wind speed mean value (15 m/s vs 13 m/s) and lower wind speed deviation (5 m/s vs 12 m/s). Furthermore, an unexpected regulation behavior is demonstrated: fast settling and peak times coincide with large variation in overshoot, undershoot and peak value of the power response. This presents a challenge in assessing performance of the integrated generation system. The proposed evaluation method and presented results are important steps to increasing the national power grid capability to accept high integration of multiple energy sources. 

  • 42.
    Yan, J.
    et al.
    North China Electric Power University, Beijing, 102206, China.
    Lai, F.
    North China Electric Power University, Beijing, 102206, China.
    Liu, Y.
    North China Electric Power University, Beijing, 102206, China.
    Yu, D. C.
    University of Wisconsin – Milwaukee, United States.
    Yi, W.
    Energy Research Institute of National Development and Reform Commission, China.
    Yan, Jinyue
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi. KTH-Royal Institute of Technology, Sweden.
    Multi-stage transport and logistic optimization for the mobilized and distributed battery2019Ingår i: Energy Conversion and Management, ISSN 0196-8904, E-ISSN 1879-2227, Vol. 196, s. 261-276Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    High share of variable renewable energy is challenging to the traditional power system technically and economically. This calls for a significant increase to the system flexibility, which might result in the costs associated with energy storage and costly upgrades to the traditional transmission and distribution system. This paper presents a multi-stage battery transportation and logistics optimization method to increase the renewable energy consumptions, economics, and mobilities of the battery utilization. A new approach is proposed in which the batteries are charged in the renewable power plants and transported back and forth by railways between the renewable power plants and cities. Based on the forecasts of battery supplies/demands, multiple optimization stages (full train transport and carpooling) are designed by the branch-and-bound algorithm and genetic algorithm respectively. The proposed battery transportation and logistics concept and model are performed using the Beijing-Tianjin-Hebei region in China as an example. The results show that the levelized cost of energy of the battery transportation and logistics model is $0.045/kWh averagely. Also, by the use of mobilized batteries, the proposed battery transportation and logistics model increases the system flexibilities and renewable energy deliveries to the end users without the reinforcement of transmission and distribution system and any constraint from a highly penetrated power system.

  • 43.
    Yan, Y.
    et al.
    China University of Petroleum-Beijing, China.
    Zhang, Haoran
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi. Center for Spatial Information Science, The University of Tokyo, Chiba, Japan.
    Liao, Q.
    China University of Petroleum-Beijing, China.
    Liang, Y.
    China University of Petroleum-Beijing, China.
    Yan, Jinyue
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Roadmap to hybrid offshore system with hydrogen and power co-generation2021Ingår i: Energy Conversion and Management, ISSN 0196-8904, E-ISSN 1879-2227, Vol. 247, artikel-id 114690Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Constrained by the expansion of the power grid, the development of offshore wind farms may be hindered and begin to experience severe curtailment or restriction. The combination of hydrogen production through electrolysis and hydrogen-to-power is considered to be a potential option to achieve the goal of low-carbon and energy security. This work investigates the competitiveness of different system configurations to export hydrogen and/or electricity from offshore plants, with particular emphasis on unloading the mixture of hydrogen and electricity to end-users on land. Including the levelized energy cost and net present value, a comprehensive techno-economic assessment method is proposed to analyze the offshore system for five scenarios. Assuming that the baseline distance is 10 km, the results show that exporting hydrogen to land through pipelines shows the best economic performance with the levelized energy cost of 3.40 $/kg. For every 10 km increase in offshore distance, the net present value of the project will be reduced by 5.69 MU$, and the project benefit will be positive only when the offshore distance is less than 53.5 km. An important finding is that the hybrid system under ship transportation mode is not greatly affected by the offshore distance. Every 10% increase in the proportion of hydrogen in the range of 70%–100% can increase the net present value by 1.43–1.70 MU$, which will increase by 7.36–7.37 MU$ under pipeline transportation mode. Finally, a sensitivity analysis was carried out to analyze the wind speed, electricity and hydrogen prices on the economic performance of these systems.

  • 44.
    Zhang, C.
    et al.
    Energy Processes Division, Royal Institute of Technology, Stockholm, Sweden.
    Campana, Pietro Elia
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi. Energy Processes Division, Royal Institute of Technology, Stockholm, Sweden.
    Yang, J.
    School of Humanities and Economic Management, China University of Geosciences, Beijing, China.
    Yu, C.
    Department of Earth System Science, Tsinghua University, Beijing, China.
    Yan, Jinyue
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi. Energy Processes Division, Royal Institute of Technology, Stockholm, Sweden.
    Economic assessment of photovoltaic water pumping integration with dairy milk production2018Ingår i: Energy Conversion and Management, ISSN 0196-8904, E-ISSN 1879-2227, Vol. 177, s. 750-764Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    As dairy consumption grows, domestic dairy farms face challenges in reducing the cost of feeds and the production of high-quality milk for market demands. This paper aims to introduce and integrate solar energy into the milk production chain to investigate its economic performance. By collecting data on milk production processes from 11 dairy farms in China, we quantified electricity usage and costs of milk production to identify the best and worst cases. Crop yields response to the water demand and the electricity requirements of the dairy farms were considered. The study simulated scenarios of self-sufficiency at 20%, 80%, and 100%, in the identified farms by integrating a photovoltaic water pumping (PVWP) system to provide both power and water for alfalfa and other feeds’ irrigation and subsequent milk production. We evaluated annual discounted cost, revenue and net profit under each scenario and case. The results showed that a dairy farm with an integrated PVWP system and self-sufficient feeds would lead to value add-ins, such as electricity saving with solar energy generation, economic cost saving of crops, and CO2 emission reduction. The analysis on return on investment (ROI) and internal rate of return (IRR) revealed that not all the self-sufficient feeds can bring positive marginal profit. Among the investigated scenarios and cases, the dairy farm marked out by the highest ROI with 3.12 and IRR with 20.4%, was the farm where the integrated PVWP system was used to reach 20% self-sufficiency (self-production of only alfalfa). The other scenarios and cases with higher levels of self-sufficiency showed lower ROIs and IRRs. This indicates that high self-production levels of feeds decrease the total profit due to high investment cost. Sensitivity analyses of crop price and operational cost were conducted for ROI with single and double factor approaches. Scale and production of feeds proportions should be carefully considered in improving the economic performance of dairy milk production.

  • 45.
    Zhang, Chi
    et al.
    School of Chemical Science and Engineering, Royal Institute of Technology.
    Campana, Pietro Elia
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Yang, Jan
    School of Chemical Science and Engineering, Royal Institute of Technology.
    Yan, Jinyue
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Economic performance of photovoltaic water pumping systems with business model innovation in China2017Ingår i: Energy Conversion and Management, ISSN 0196-8904, E-ISSN 1879-2227, Vol. 33, nr 1, s. 498-510Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Expansion by photovoltaic (PV) technologies in the renewable energy market requires exploring added value integrated with business model innovation. In recent years, a pilot trial of PV water pumping (PVWP) technologies for the conservation of grassland and farmland has been conducted in China. In this paper, we studied the added value of the PVWP technologies with an emphasis on the integration of the value proposition with the operation system and customer segmentation. Using the widely used existing PV business models (PV-roof) as a reference, we evaluated discounted cash flow (DCF) and net present value (NPV) under the scenarios of traditional PV roof, PVWP pilot, PVWP scale-up, and PVWP social network, where further added value via social network was included in the business model. The results show that the integrated PVWP system with social network products significantly improves the performance in areas such as the discounted payback period, internal rate of return (IRR), and return on investment (ROI). We conclude that scenario PVWP social network with business model innovation, can result in value add-ins, new sources of revenue, and market incentives. The paper also suggests that current policy incentives for PV industry are not efficient due to a limited source of revenue, and complex procedures of feed-in tariff verification.

  • 46.
    Zhang, Xiaojing
    et al.
    ABB AB, Corp Res, Västerås, Sweden.
    Yan, Jinying
    Vattenfall AB, Stockholm, Sweden.
    Li, Hailong
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Chekani, Shabnam
    Royal Inst Technol,Stockholm, Sweden.
    Liu, Loncheng
    Royal Inst Technol,Stockholm, Sweden.
    Investigation of thermal integration between biogas production and upgrading2015Ingår i: Energy Conversion and Management, ISSN 0196-8904, E-ISSN 1879-2227, Vol. 102, s. 131-139Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Thermal integration of anaerobic digestion (AD) biogas production with amine-based chemical absorption biogas upgrading has been studied to improve the overall efficiency of the intergraded system. The thermal characteristics have been investigated for industrial AD raw biogas production and amine-based chemical absorption biogas upgrading. The investigation provides a basic understanding for the possibilities of energy saving through thermal integration. The thermal integration is carried out through well-defined cases based on the thermal characteristics of the biogas production and the biogas upgrading. The following factors are taken into account in the case study: thermal conditions of sub-systems, material and energy balances, cost issues and main benefits. The potential of heat recovery has been evaluated to utilise the waste heat from amine-based upgrading process for the use in the AD biogas production. The results show that the thermal integration has positive effects on improving the overall energy efficiency of the integrated biogas plant. Cost analysis shows that the thermal integration is economically feasible. 

  • 47.
    Zhang, Xingjin
    et al.
    Northwest A & F Univ, Key Lab Agr Soil & Water Engn Arid & Semiarid Area, Minist Educ, Yangling 712100, Shaanxi, Peoples R China.;Northwest A & F Univ, Inst Water Resources & Hydropower Res, Yangling 712100, Shaanxi, Peoples R China..
    Campana, Pietro Elia
    Mälardalens universitet, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Bi, Xiaojian
    Powerchina Northwest Engn Corp Ltd, Xian 710065, Peoples R China..
    Egusquiza, Monica
    Xu, Beibei
    Northwest A & F Univ, Key Lab Agr Soil & Water Engn Arid & Semiarid Area, Minist Educ, Yangling 712100, Shaanxi, Peoples R China.;Northwest A & F Univ, Inst Water Resources & Hydropower Res, Yangling 712100, Shaanxi, Peoples R China.;Powerchina Northwest Engn Corp Ltd, Xian 710065, Peoples R China..
    Wang, Cong
    China Inst Water Resources & Hydropower Res, Beijing 100038, Peoples R China..
    Guo, Hongyan
    Powerchina Northwest Engn Corp Ltd, Xian 710065, Peoples R China..
    Chen, Diyi
    Northwest A & F Univ, Key Lab Agr Soil & Water Engn Arid & Semiarid Area, Minist Educ, Yangling 712100, Shaanxi, Peoples R China.;Northwest A & F Univ, Inst Water Resources & Hydropower Res, Yangling 712100, Shaanxi, Peoples R China..
    Egusquiza, Eduard
    Polytech Univ Catalonia UPC, Ctr Ind Diagnost CDIF, Barcelona, Spain..
    Capacity configuration of a hydro-wind-solar-storage bundling system with transmission constraints of the receiving-end power grid and its techno-economic evaluation2022Ingår i: Energy Conversion and Management, ISSN 0196-8904, E-ISSN 1879-2227, Vol. 270, artikel-id 116177Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The hydro-wind-solar-storage bundling system plays a critical role in solving spatial and temporal mismatch problems between renewable energy resources and the electric load in China. An efficient bundling system ca-pacity configuration can improve the consumption level and reduce the renewable energy transmission cost. However, the restriction between economic feasibility and technical transmission constraints of the bundling system is not well understood. This restriction is becoming more and more obvious with the decrease of renewable energy price compensation year by year. This study compares the role of technical and economic indicators of capacity configuration, as well as the constraint relationship between electricity price and trans-mission constraints. Three screening principles of capacity configuration are proposed to reveal the techno-economic interaction. This paper explores a practical engineering case of Northwest China using a bundling system capacity configuration model. The internal rate of return is assumed as 8% for the bundling system. The results show that reducing the wind curtailment rate can effectively reduce the cost per MWh when the trans-mission guarantee rate is larger than 90%. Moreover, an integrated feed-in tariff based on market competi-tiveness is obtained if the wind curtailment rate is controlled by 5%. For example, the integrated feed-in tariff is 463.7 RMB/MWh when the wind curtailment rate is less than 5% and the transmission guarantee rate is larger than 95%. These results verify that the techno-economic interaction of the bundling system offers important theoretical support for selecting techno-economic indicators and capacity configuration.

  • 48.
    Zhang, Y.
    et al.
    KTH Royal Institute of Technology, Stockholm, Sweden.
    Lundblad, Anders
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi. KTH Royal Institute of Technology, Stockholm, Sweden.
    Campana, Pietro Elia
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Benavente, F.
    KTH Royal Institute of Technology, Stockholm, Sweden.
    Yan, Jinyue
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi. KTH Royal Institute of Technology, Stockholm, Sweden.
    Battery sizing and rule-based operation of grid-connected photovoltaic-battery system: A case study in Sweden2017Ingår i: Energy Conversion and Management, ISSN 0196-8904, E-ISSN 1879-2227, Vol. 133, s. 249-263Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The optimal components design for grid-connected photovoltaic-battery systems should be determined with consideration of system operation. This study proposes a method to simultaneously optimize the battery capacity and rule-based operation strategy. The investigated photovoltaic-battery system is modeled using single diode photovoltaic model and Improved Shepherd battery model. Three rule-based operation strategies—including the conventional operation strategy, the dynamic price load shifting strategy, and the hybrid operation strategy—are designed and evaluated. The rule-based operation strategies introduce different operation parameters to run the system operation. multi-objective Genetic Algorithm is employed to optimize the decisional variables, including battery capacity and operation parameters, towards maximizing the system's Self Sufficiency Ratio and Net Present Value. The results indicate that employing battery with the conventional operation strategy is not profitable, although it increases Self Sufficiency Ratio. The dynamic price load shifting strategy has similar performance with the conventional operation strategy because the electricity price variation is not large enough. The proposed hybrid operation strategy outperforms other investigated strategies. When the battery capacity is lower than 72 kW h, Self Sufficiency Ratio and Net Present Value increase simultaneously with the battery capacity.

  • 49.
    Zhang, Yang
    et al.
    KTH Royal Inst Technol, Div Energy Proc, SE-10044 Stockholm, Sweden..
    Campana, Pietro Elia
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi. KTH Royal Inst Technol, Div Energy Proc, SE-10044 Stockholm, Sweden.; Malardalen Univ, Sch Business Soc & Engn, SE-72123 Vasteras, Sweden..
    Anders, Lundblad
    RISE Res Inst Sweden, Div Safety & Transport Elect, SE-50462 Boras, Sweden..
    Zheng, Wandong
    Tianjin Univ, Sch Environm Sci & Technol, Tianjin 300072, Peoples R China..
    Yan, Jinyue
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi. KTH Royal Inst Technol, Div Energy Proc, SE-10044 Stockholm, Sweden.; Malardalen Univ, Sch Business Soc & Engn, SE-72123 Vasteras, Sweden..
    Planning and operation of an integrated energy system in a Swedish building2019Ingår i: Energy Conversion and Management, ISSN 0196-8904, E-ISSN 1879-2227, Vol. 199, artikel-id 111920Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    More flexibility measures are required due to the increasing capacities of variable renewable energies (VRE). In buildings, the integration of energy supplies forms integrated energy systems (IES). IESs can provide flexibility and increase the VRE penetration level. To upgrade a current building energy system into an IES, several energy conversion and storage components are needed. How to decide the component capacities and operate the IES were investigated separately in studies on system planning and system operation. However, a research gap exists that the system configuration from system planning is not validated by actual operation conditions in system operation. Meanwhile, studies on system operation assume that IES configurations are predetermined. This work combines system planning and system operation. The IES configuration is determined by mixed integer linear programming in system planning. Actual operation conditions and forecast errors are considered in system operation. The actual operation profiles are obtained through year-round simulations of different energy management systems. The results indicate that the system configuration from system planning can meet energy demands in system operation. Among different energy management systems, the combination of robust optimization and receding horizon optimization achieves the lowest yearly operation cost. Meanwhile, two scenarios that represent high and low forecast accuracies are studied. Under the high and low forecast accuracy scenarios, the yearly operation costs are about 4% and 6% higher than that obtained from system planning.

  • 50.
    Zhao, R.
    et al.
    KTH Royal Institute of Technology, Stockholm, Sweden.
    Liu, L.
    KTH Royal Institute of Technology, Stockholm, Sweden.
    Zhao, L.
    Ministry of Education of China, Tianjin, China.
    Deng, S.
    Ministry of Education of China, Tianjin, China.
    Li, S.
    Ministry of Education of China, Tianjin, China.
    Zhang, Y.
    Ministry of Education of China, Tianjin, China.
    Li, Hailong
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Thermodynamic exploration of temperature vacuum swing adsorption for direct air capture of carbon dioxide in buildings2019Ingår i: Energy Conversion and Management, ISSN 0196-8904, E-ISSN 1879-2227, Vol. 183, s. 418-426Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Abrupt climate change such as the loss of Arctic sea-ice area urgently needs negative emissions technologies. The potential application of direct air capture of carbon dioxide from indoor air and outdoor air in closed buildings or crowded places has been discussed in this paper. From the aspects of carbon reduction and indoor comfort, the ventilation system integrating a capture device is of great value in practical use. For ultra-dilute carbon dioxide sources, many traditional separation processes have no cost advantages, but adsorption technologies such as temperature vacuum swing adsorption is one of suitable methods. Thermodynamic exploration has been investigated regarding minimum separation work and second-law efficiency at various concentrations in the air. The influence of concentration, adsorption temperature, desorption temperature and desorption pressure on the energy efficiency has also been evaluated. Results show that the minimum separation work for the level of 400 ppm is approximately 20 kJ/mol. The optimal second-law efficiencies are 44.57%, 37.55% and 31.60%, respectively for 3000 ppm, 2000 ppm and 1000 ppm. It means that a high energy-efficiency capture device in buildings merits attention in the exploration of the possibility of approaching negative carbon buildings. 

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