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  • 301.
    Li, Hailong
    et al.
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Song, Jingjing
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Sun, Q.
    Institute of Thermal Science and Technology, Shandong University, Jinan, China.
    Wallin, Fredrik
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Zhang, Q.
    China Petroleum University, Beijing, China.
    A dynamic price model based on levelized cost for district heating2019Ingår i: Energy, Ecology and Environment, ISSN 2363-7692, Vol. 4, nr 1, s. 15-25Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    District Heating (DH) is facing a tough competition in the market. In order to improve its competence, an effective way is to reform price models for DH. This work proposed a new dynamic price model based on the levelized cost of heat (LCOH) and the predicted hourly heat demand. A DH system in Sweden was used as a case study. Three methods were adopted to allocate the fuel cost to the variable costs of heat production, including (1) in proportion to the amount of heat and electricity generation; (2) in proportion to the exergy of generated heat and electricity; and (3) deducting the market price of electricity from the total cost. Results indicated that the LCOH-based pricie model can clearly reflect the production cost of heat. Through the comparison with other market-implemented price models, it was found that even though the market-implemented price models can, to certain extent, reflect the variations in heat demand, they cannot reflect the changes in production cost when different methods of heat production are involved. In addition, price model reforming can lead to a significant change in the expense of consumers and consequently, affect the selection of heating solution.

  • 302.
    Li, Hailong
    et al.
    Mälardalens högskola, Akademin för innovation, design och teknik. Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Tan, Y.
    Royal Institute of Technology, Stockholm, Sweden.
    Ditaranto, M.
    SINTEF Energy, Trondheim, Norway.
    Yan, J.
    Royal Institute of Technology, Stockholm, Sweden.
    Yu, Z.
    University of Stavanger, Norway.
    Capturing CO2 from Biogas Plants2017Ingår i: Energy Procedia, Elsevier Ltd , 2017, s. 6030-6035Konferensbidrag (Refereegranskat)
    Abstract [en]

    As a renewable energy, biogas produced from anaerobic digestion and landfill is playing a more and more important role in the energy market. Capturing CO2 from biogas can result in a negative CO2 emission. Depending on how biogas is utilized, there are different routes to capture CO2. A biogas plant that uses raw biogas to produce power and heat can be retrofitted by integrating CO2 capture. In order to identify the best option, three retrofits were compared from both technical and economic perspectives, including SYS-I, which captures CO2 from raw gas and produces biomethane instead of electricity and heat, SYS-II, which captures CO2 using MEA-based chemical absorption after the combustion of raw gas, and SYS-III, which captures CO2 by using oxy-fuel combustion of the raw gas. In general, SYS-I can achieve the highest profit and shortest payback time, mainly due to the high price of biomethane. SYSII and SYS-III are clearly influenced by carbon credit. In order to have positive profits for the retrofits of SYS-II and SYS-III, carbon credit needs to exceed 750SEK (or 100USD)/ton CO2 and 113 SEK (or 15USD)/ton CO2 respectively.

  • 303.
    Li, Hailong
    et al.
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Wang, Bin
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Yan, Jinyue
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi. KTH Royal Institute of Technology, Stockholm, Sweden.
    Salman, Chaudhary Awais
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Thorin, Eva
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Schwede, Sebastian
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Performance of flue gas quench and its influence on biomass fueled CHP2019Ingår i: Energy, ISSN 0360-5442, E-ISSN 1873-6785, Vol. 180, s. 934-945Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    For biomass/waste fueled power plants, stricter regulations require a further reduction of the negative impacts on the environment caused by the release of pollutants and withdrawal of fresh water externally. Flue gas quench (FGQ) is playing an important role in biomass or waste fueled combined heat and power (CHP) plants, as it can link the flue gas (FG) cleaning, energy recovery and wastewater treatment. Enhancing water evaporation can benefit the concentrating of pollutant in the quench water; however, when FG condenser (FGC) is not in use, it results in a large consumption of fresh water. In order to deeply understand the operation of FGQ, a mathematic model was developed and validated against the measurements. Based on simulation results key parameters affecting FGQ have been identified, such as the flow rate and temperature of recycling water and the moisture content of FG. A guideline about how to reduce the discharge of wastewater to the external and the withdrawal of external water can be proposed. The mathematic model was also implemented into an ASPEN Plus model about a CHP plant to assess the impacts of FGQ on CHP. Results show that when the FGC was running, increasing the flow rate and decreasing the temperature of recycling water can result in a lower total energy efficiency. 

  • 304.
    Li, Hailong
    et al.
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Wilhelmsen, Øivind
    SINTEF Energy Research, Trondheim, Norway.
    Yan, Jinyue
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi. Royal Institute of Technology (KTH), Stockholm, Sweden.
    Properties of CO2-mixtures and impacts on Carbon Capture2015Ingår i: Handbook of Clean Energy Systems / [ed] Jinyue Yan, John Wiley & Sons, 2015, s. 1-17Kapitel i bok, del av antologi (Refereegranskat)
  • 305.
    Li, Hailong
    et al.
    Mälardalens högskola, Akademin för hållbar samhälls- och teknikutveckling.
    Yan, Jinyue
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik.
    Campana, Pietro Elia
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik.
    Feasibility of integrating solar energy into a power plant with amine-based chemical absorption for CO2 capture2012Ingår i: International Journal of Greenhouse Gas Control, ISSN 1750-5836, E-ISSN 1878-0148, Vol. 9, s. 272-280Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Solar thermal energy has the potential to supply the thermal demand of stripper reboiler in the power plant with amine-based post combustion CO2 capture. The performance of a power plant integrated with solar assisted post combustion CO2 capture (SCC) is largely affected by the local climatic conditions, such as solar irradiation, sunshine hours and ambient temperature, the type of solar thermal collector and CO2 recovery ratio. The feasibility evaluation results about such a power plant show that the cost of electricity (COE) and cost of CO2 avoidance (COA) are mainly determined by the local climatic conditions. For the locations having higher solar irradiation, longer sunshine hours and higher ambient temperature, the power plant with SCC has lower COE and COA. COE and COA are sensitive to the prices of solar thermal collectors. In order to achieve lower COE and COA compared to the power plant integrated with non-solar assisted post combustion capture, the price of solar thermal collector has to be lower than 150 USD/m(2) and 90 USD/m(2) for the solar trough and vacuum tube, respectively.

  • 306.
    Li, Hailong
    et al.
    Mälardalens högskola, Akademin för hållbar samhälls- och teknikutveckling. Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Yan, Jinyue
    Mälardalens högskola, Akademin för hållbar samhälls- och teknikutveckling. Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Dahlquist, Erik
    Mälardalens högskola, Akademin för hållbar samhälls- och teknikutveckling. Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Economic assessment of the mobilized thermal energy storage (M-TES) system for distributed heat supply2013Ingår i: Applied Energy, ISSN 0306-2619, E-ISSN 1872-9118, Vol. 104, s. 178-186Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    A conceptual system, mobilized thermal energy storage system (M-TES), was proposed for distributed heat supply. The economic evaluation that is essential to identify the key issues and provide guidelines regarding system improvement was conducted in this paper. Results show that the cost using M-TES to supply heat (COH) is primarily determined by the transport distance and the heat demand. The variation of COH is proportional to the transport distance, but inversely proportional to the heat demand. According to the sensitivity study, COH is more sensitive to the price of phase change material (PCM) than other parameters, such as the transport cost. Moreover, it is possible for an M-TES system to compete with other heat supply methods, such as pellet/bio-oil/biogas/oil boiler systems and electrical air-source heat pump. When using M-TES to replace the existing system, the payback time is mainly determined by the transport distance and the heat demand. Water is another potential working fluid for M-TES system. Comparatively, using PCM is more suitable for cases with larger heat demand or longer transport distance.

  • 307.
    Li, Hailong
    et al.
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Yang, Wenyan
    Tianjin Univ, Peoples R China.
    Yu, Zhixin
    Univ Stavanger, Stavanger, Norway.
    Zhao, Li
    Tianjin Univ, Peoples R China.
    The performance of a heat pump using nanofluid (R22+TiO2) as the working fluid - an experimental study2015Ingår i: Energy Procedia, ISSN 1876-6102, E-ISSN 1876-6102, Vol. 75, s. 1838-1843Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    It has been well known that the nano-particles, including metals, oxides, carbides, or carbon nanotubes, can increase the conduction and convection coefficients and consequently, enhance the heat transfer. Using nanofluids as working fluids in the refrigeration, air-conditioning and heat pump systems has attracted much attention. This work set-up a test rig to experimentally study the system performance of a heat pump with nanofluid as refrigerant, which was prepared by mixing 5wt% TiO2 with R22. Results show that adding the nano particle TiO2 didn't changed the heat absorbed in the evaporator clearly but increase the heat released in the condenser. As a results, compared to using pure R22, when using R22 + TiO2, the COP of the cooling cycle was decreased slightly, however, the COP of the heating cycle was increased significantly increased power consumption of compression.

  • 308.
    Li, W.
    et al.
    College of Chemical Engineering, Beijing University of Chemical Technology, Beijing, China.
    Khalid, H.
    College of Chemical Engineering, Beijing University of Chemical Technology, Beijing, China.
    Zhu, Z.
    College of Chemical Engineering, Beijing University of Chemical Technology, Beijing, China.
    Zhang, R.
    Department of Biological and Agricultural Engineering, University of California, Davis, CA, United States.
    Liu, G.
    College of Chemical Engineering, Beijing University of Chemical Technology, Beijing, China.
    Chen, Chang
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi. College of Chemical Engineering, Beijing University of Chemical Technology, Beijing, China.
    Thorin, Eva
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Methane production through anaerobic digestion: Participation and digestion characteristics of cellulose, hemicellulose and lignin2018Ingår i: Applied Energy, ISSN 0306-2619, E-ISSN 1872-9118, Vol. 226, s. 1219-1228Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Lignocellulosic biomass is the most abundant natural resource with high biomethane potential. However, complex structure of lignocellulosic biomass has hampered the efficient utilization of this bioresource. Previous studies have investigated the overall anaerobic digestion performance of lignocellulosic biomass, but the individual participation of each lignocellulosic component during anaerobic digestion remained unclear. Thus, this study investigated the methane production characteristics of cellulose, hemicellulose, lignin and their mixtures along with the microbial communities involved in anaerobic digestion. The results showed that the biomethane potential of cellulose was higher than that of hemicellulose; however, hemicellulose was hydrolysed more quickly than cellulose, while lignin was very difficult to be digested. The higher concentrations of acetic, n-butyric and n-valeric acids hydrolysed from the hemicellulose resulted in a lower pH and more severe inhibition on methane production than that of cellulose, and the methanogenesis gradually recovered after pH adjustment. The co-digestion of cellulose and hemicellulose increased the methane yield and biodegradability compared to mono-digestions. The addition of lignin to cellulose brought more significant decrease in the methane yield of cellulose than that of hemicellulose. Substrate-related bacteria such as Clostridium sensu stricto, Lutaonella, Cloacibacillus and Christensenella showed higher relative abundance in cellulose digestate, and sugar-fermenting bacteria such as Saccharofermentans, Petrimonas and Levilinea were more rich in the digestate of hemicellulose. Moreover, methanogenic Methanospirillum and Methanothrix likely contributed to the methane production of cellulose, while aciduric methanogens from Methanobrevibacter, Methanomassiliicoccus, Methanobacterium and Methanoculleus contributed to that of hemicellulose. This study provides a deeper understanding of the mechanism in the bioconversion of lignocellulosic biomass during anaerobic digestion.

  • 309.
    Li, X.
    et al.
    School of Environmental Science and Engineering, Tianjin University, Tianjin, China.
    Zhu, K.
    School of Environmental Science and Engineering, Tianjin University, Tianjin, China.
    Li, Hailong
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi. Key Laboratory of Refrigeration Technology of Tianjin, Tianjin University of Commerce, Tianjin, China.
    Chen, X.
    Key Laboratory of Refrigeration Technology of Tianjin, Tianjin University of Commerce, Tianjin, China.
    Wang, Y.
    Key Laboratory of Refrigeration Technology of Tianjin, Tianjin University of Commerce, Tianjin, China.
    Performance comparison regarding loop heat pipes with different evaporator structures2019Ingår i: International journal of thermal sciences, ISSN 1290-0729, E-ISSN 1778-4166, Vol. 136, s. 86-95Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The design of evaporator can clearly affect the performance of loop heat pipes (LHPs). In order to understand the influence, three different designs of evaporators were compared, including embedding vapor channels on the heating surface (Config_1), embedding vapor channels in the wick (Config_2), and separating the wick from the heating surface (Config_3). Based on the validated model, the operating temperature, the start-up time, and the transport distance, as key performance indicators, were studied. Results show that, to improve the performance of LHP, it is of importance to reduce the contacting area between the wick and the heating surface. Due to the existence of the steam chamber, the wick was separated from the heating surface in Config_3, resulting in the lowest operating temperature and the shortest start-up time. The pressure head of evaporation is also an important component of the driving force. For Config_3, since the evaporation happened in the steam chamber rather than in the wick, it had a longer transport distance than Config_1 and Config_2 at the same heat load.

  • 310.
    Li, Xueqiang
    et al.
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi. Tianjin University, Tianjin, China; Tianjin University of Commerce, Tianjin, China.
    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. Tianjin University of Commerce, Tianjin, China.
    Yan, Jinyue
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Zhu, K.
    Tianjin University of Commerce, Tianjin, China.
    Energy storage systems for refrigerated warehouses2017Ingår i: Energy Procedia, ISSN 1876-6102, E-ISSN 1876-6102, Vol. 143, s. 94-99Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    To reduce the peak load, dynamic electricity price schemes have been widely used. Refrigerated warehouses consume a large amount of energy, most of which happens during the daytime due to the higher ambient temperature. This work evaluated the potential benefits of integrating energy storage in the refrigerated warehouses. Two types of energy storage systems have been considered, including a cold energy storage system and an electrical energy storage system. A dynamic model has been developed in TRNSYS to study the performance of those two energy storage systems and assess the benefits. Results show that using the cold energy storage to shift power consumption from daytime to nighttime can increase the energy efficiency of the refrigeration system. However, as the electrical energy storage system can shift more power consumption, it can achieve a large cost saving. Compared to the reference system without energy storage, the introductions of a cold energy storage system and an electrical energy storage system can reduce the operational cost by 10 and 53.7% respectively. 

  • 311.
    Li, Xueqiang
    et al.
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi. Tianjin University of Commerce, Tianjin, China.
    Schwede, Sebastian
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Li, Hailong
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi. Tianjin University of Commerce, Tianjin, China.
    Yu, X.
    University of Shanghai for Science and Technology, Shanghai, China.
    Yu, Z.
    University of Stavanger, Stavanger, Norway.
    Zhu, K.
    Tianjin University, Tianjin, China.
    Toxicity of ionic liquid on anaerobic digestion2017Ingår i: Energy Procedia, ISSN 1876-6102, E-ISSN 1876-6102, Vol. 142, s. 938-942Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Anaerobic digestion is a straightforward process to produce energy from biomass. However, the lignin composed of phenylpropanoid units induces a strong resistance for the hydrolysis step. Ionic liquids (ILs) have been applied in biomass pretreatment to dissolve the biomass components and enhance the anaerobic digestion. However, there are still some challenges such as the toxicity. ILs could inhibit the digestion process and reduce the CH4 production. In this work, a toxicity test for [BMIM]Cl (1-chlorobutane and N-methylimidazole) was conducted. Results show that IL has a strong inhibition and lowered CH4 production when its concentration was higher. At 0.2305±0.0116 g L-1 and 0.4367±0.0219 g L-1, the anaerobic digestion process was inhibited by 10 and 50%, respectively. Accordingly, a higher recovery ratio or a lower pretreatment ratio are necessary to avoid the negative impact of inhibition on BMP. 

  • 312.
    Li, Y.
    et al.
    Tsinghua University, Beijing, China.
    Jin, Y.
    Tsinghua University, Beijing, China.
    Li, Hailong
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Borrion, A.
    University College London, London, United Kingdom.
    Yu, Z.
    University of Stavanger, Stavanger, Norway.
    Li, J.
    Tsinghua University, Beijing, China.
    Kinetic studies on organic degradation and its impacts on improving methane production during anaerobic digestion of food waste2018Ingår i: Applied Energy, ISSN 0306-2619, E-ISSN 1872-9118, Vol. 213, s. 136-147Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Organics degradation is vital for food waste anaerobic digestion performance, however, the influence of organics degradation on biomethane production process has not been fully understood. This study aims to thoroughly investigate the organics degradation performance and identify the interaction between the reduction of organic components and methane yield based on the evaluation on 12 types of food waste. Five models (i.e. exponential, Fitzhugh, transference function, Cone and modified Gompertz models) were compared regarding the prediction of organic degradation and the results showed that the exponential model fit the experiments best, whereas kinetic parameters could not be commonly used for all situations. The exponential model was then used to study the impacts of organics reduction on the methane production and results revealed that the cumulative methane production (385–627 mL/g volatile solid) increased exponentially with the removal efficiency of volatile solids, lipids, and proteins for all feedstocks, whereas volatile solid reduction increased exponentially and linearly, respectively, with the removal efficiency of lipids and proteins. Additionally, protein degradation increased exponentially with the reduction efficiency of lipids. The experimental data and model simulation results suggested that higher methane production (530–548 mL/g volatile solid) and removal efficiency of volatile solids (65.0–67.8%), lipids (77.8–78.2%), and proteins (54.7–58.2%) could be achieved in a shorter digestion retention when carbohydrate content was higher than 47.6%, protein content lower than 24.1%, and lipid content lower than 28.3%.

  • 313.
    Li, Y.
    et al.
    Tsinghua University, Beijing, China.
    Jin, Y.
    Tsinghua University, Beijing, China.
    Li, J.
    Tsinghua University, Beijing, China.
    Li, Hailong
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Yu, Z.
    University of Stavanger, Stavanger, Norway .
    Effects of thermal pretreatment on the biomethane yield and hydrolysis rate of kitchen waste2016Ingår i: Applied Energy, ISSN 0306-2619, E-ISSN 1872-9118, Vol. 172, s. 47-58Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    In this study, batch tests were performed to evaluate the effects of different thermal pretreatment temperatures (55-160 °C) and durations (15-120 min) on the anaerobic digestion of kitchen waste (KW). Two commonly used approaches, namely the modified Gompertz model and the approach developed by Koch and Drewes, were applied to assess the effects of the different pretreatment parameters on the biomethane yield, lag time and hydrolysis rate constant via data fitting. The subsequent anaerobic digestion of KW pretreated at 55-120 °C presented greater efficiency, and longer treatment durations resulted in increased methane production and higher hydrolysis rate constants. These findings were obtained due to the lower nutrient loss observed in KW treated at lower temperature treatments compared with that found with higher temperature treatments. In general, the effects of thermal pretreatment on the lag phase and hydrolysis rate differed depending on the treatment parameters leading to the variations in the KW compositions. The soundness of the two model results was evaluated, and higher statistical indicators (R2) were found with the modified Gompertz model than with the approach developed by Koch and Drewes. 

  • 314.
    Li, Y.
    et al.
    Tsinghua University, Beijing, China .
    Jin, Y.
    School of Environment, Tsinghua University, Beijing, China.
    Li, J.
    School of Environment, Tsinghua University, Beijing, China.
    Li, Hailong
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Yu, Z.
    University of Stavanger, Stavanger, Norway .
    Nie, Y.
    School of Environment, Tsinghua University, Beijing, China .
    Effects of thermal pretreatment on degradation kinetics of organics during kitchen waste anaerobic digestion2017Ingår i: Energy, ISSN 0360-5442, E-ISSN 1873-6785, Vol. 118, s. 377-386Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The influence of thermal pretreatment on degradation properties of organics in kitchen waste (KW) was investigated. The kinetics results showed that thermal pretreatment could enhance the degradation efficiency of crude protein (CP), fat, oil and grease (FOG), volatile solid (VS) and volatile fatty acids (VFA). Thermal pretreatment showed no significant difference in the final concentration of protein but could decrease the FOG degradation potential (7–36%), while increased the lag phase for degradation of protein and FOG respectively by 35–65% and 11–82% compared with untreated KW. Cumulative biogas yield increased linearly and exponentially with the removal efficiency of VS and other organics (CP and FOG) respectively. Additionally, the reduction of CP increased exponentially with FOG removal efficiency. The calculating methods of biogas yield, organics reduction and corresponding appropriate digestion retention based on FOG and CP reduction amount and pretreatment parameters were suggested.

  • 315.
    Li, Yangyang
    et al.
    Tsinghua University.
    Jin, Yiying
    Tsinghua University.
    Borrion, Aiduan
    University College London.
    Li, Hailong
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Current status of food waste generation and management in China2019Ingår i: Bioresource Technology, ISSN 0960-8524, E-ISSN 1873-2976, Vol. 273, s. 654-665Artikel i tidskrift (Refereegranskat)
  • 316.
    Li, Yangyang
    et al.
    Tsinghua Univ, Sch Environm, Beijing 100084, Peoples R China.;Tsinghua Univ, Minist Educ China, Key Lab Solid Waste Management & Environm Safety, Beijing 100084, Peoples R China..
    Jin, Yiying
    Tsinghua Univ, Sch Environm, Beijing 100084, Peoples R China.;Tsinghua Univ, Minist Educ China, Key Lab Solid Waste Management & Environm Safety, Beijing 100084, Peoples R China..
    Borrion, Aiduan
    UCL, Dept Civil Environm & Geomat Engn, London WC1E 6BT, England..
    Li, Hailong
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Li, Jinhui
    Tsinghua Univ, Sch Environm, Beijing 100084, Peoples R China.;Tsinghua Univ, Minist Educ China, Key Lab Solid Waste Management & Environm Safety, Beijing 100084, Peoples R China..
    Effects of organic composition on mesophilic anaerobic digestion of food waste (vol 244, pg 213, 2017)2018Ingår i: Bioresource Technology, ISSN 0960-8524, E-ISSN 1873-2976, Vol. 263, s. 678-678Artikel i tidskrift (Refereegranskat)
  • 317.
    Li, Yangyang
    et al.
    Tsinghua Univ, Sch Environm, Beijing 100084, Peoples R China.;Tsinghua Univ, Minist Educ China, Key Lab Solid Waste Management & Environm Safety, Beijing 100084, Peoples R China..
    Jin, Yiying
    Tsinghua Univ, Sch Environm, Beijing 100084, Peoples R China.;Tsinghua Univ, Minist Educ China, Key Lab Solid Waste Management & Environm Safety, Beijing 100084, Peoples R China..
    Li, Hailong
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Borrion, Aiduan
    UCL, Dept Civil Environ & Geomat Eng, London WC1E 6BT, England..
    Yu, Zhixin
    Univ Stavanger, Dept Petr Engn, N-4036 Stavanger, Norway..
    Li, Jinhui
    Tsinghua Univ, Sch Environm, Beijing 100084, Peoples R China.;Tsinghua Univ, Minist Educ China, Key Lab Solid Waste Management & Environm Safety, Beijing 100084, Peoples R China..
    Kinetic studies on organic degradation and its impacts on improving methane production during anaerobic digestion of food waste (vol 213, pg 135, 2018)2018Ingår i: Applied Energy, ISSN 0306-2619, E-ISSN 1872-9118, Vol. 229, s. 1284-1284Artikel i tidskrift (Refereegranskat)
  • 318.
    Li, Yangyang
    et al.
    Tsinghua Univ, Sch Environm, Beijing 100084, Peoples R China..
    Jin, Yiying
    Tsinghua Univ, Sch Environm, Beijing 100084, Peoples R China..
    Li, Jinhui
    Tsinghua Univ, Sch Environm, Beijing 100084, Peoples R China..
    Li, Hailong
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Yu, Zhixin
    Univ Stavanger, Dept Petr Engn, N-4036 Stavanger, Norway..
    Effects of thermal pretreatment on the biomethane yield and hydrolysis rate of kitchen waste (vol 172, pg 45, 2016)2018Ingår i: Applied Energy, ISSN 0306-2619, E-ISSN 1872-9118, Vol. 229, s. 1285-1285Artikel i tidskrift (Refereegranskat)
  • 319.
    Li, Yangyang
    et al.
    Tsinghua Univ, Sch Environm, Beijing 100084, Peoples R China.;Tsinghua Univ, Minist Educ China, Key Lab Solid Waste Management & Environm Safety, Beijing 100084, Peoples R China..
    Jin, Yiying
    Tsinghua Univ, Sch Environm, Beijing 100084, Peoples R China.;Tsinghua Univ, Minist Educ China, Key Lab Solid Waste Management & Environm Safety, Beijing 100084, Peoples R China..
    Li, Jinhui
    Tsinghua Univ, Sch Environm, Beijing 100084, Peoples R China.;Tsinghua Univ, Minist Educ China, Key Lab Solid Waste Management & Environm Safety, Beijing 100084, Peoples R China..
    Li, Hailong
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Yu, Zhixin
    Univ Stavanger, Dept Petr Engn, N-4036 Stavanger, Norway..
    Nie, Yongfeng
    Tsinghua Univ, Sch Environm, Beijing 100084, Peoples R China.;Tsinghua Univ, Minist Educ China, Key Lab Solid Waste Management & Environm Safety, Beijing 100084, Peoples R China..
    Effects of thermal pretreatment on degradation kinetics of organics during kitchen waste anaerobic digestion (vol 118, pg 377, 2017)2018Ingår i: Energy, ISSN 0360-5442, E-ISSN 1873-6785, Vol. 153, s. 1089-1089Artikel i tidskrift (Refereegranskat)
  • 320.
    Li, Yuying
    et al.
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi. Nanyang Normal University, China.
    Ren, Xuemin
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi. Nanyang Normal University, China.
    Dahlquist, Erik
    Mälardalens högskola, Akademin för hållbar samhälls- och teknikutveckling. Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Fan, Panpan
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi. Nanyang Normal University, China.
    Chao, T.
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi. Nanyang Normal University, China.
    Biogas Potential from Vetiveria zizaniodes (L.) Planted for Ecological Restoration in China2014Ingår i: Applied energy conference proceedings, ISSN 0306-2619, Vol. 61, s. 2733-2736Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Biogas is a promising renewable fuel all over the world. The experiment of biogas productivity from vetiver (Vetiveria zizanioides L.) was carried out to study the effect of different harvest times on the biogas yield and the dynamics of some fermentation parameters during 2011-2012. Micro-aerobic fermentation technology is used at the pretreatment of the vetiver plants. The batch anaerobic digestion technology and drainage collection process were used. The results showed that the harvest time of vetiver plants had greater effect on the biogas yield. There were more deferences among the biogas yield, daily biogas yield and biomass utilization of the plants growing at different stages. Plant nutrient had less changes during anaerobic fermentation. The results suggested that Vetiveria zizanioides could be used as a raw material of biogas production and both ecological protect and energy production could exist in a mutually beneficial system.

  • 321.
    Liang, X.
    et al.
    China United Northwest Institute for Engineering Design and Research Co., Ltd, Xi'an, China.
    Tian, W.
    China United Northwest Institute for Engineering Design and Research Co., Ltd, Xi'an, China.
    Li, R.
    Shaanxi Energy environmental and Building Energy Conservation Engineering Technology Research Center, Xi'an, China.
    Niu, Z.
    Shaanxi Energy environmental and Building Energy Conservation Engineering Technology Research Center, Xi'an, China.
    Yang, X.
    Shaanxi Energy environmental and Building Energy Conservation Engineering Technology Research Center, Xi'an, China.
    Meng, X.
    Shaanxi Energy environmental and Building Energy Conservation Engineering Technology Research Center, Xi'an, China.
    Jin, L.
    Shaanxi Energy environmental and Building Energy Conservation Engineering Technology Research Center, Xi'an, China.
    Yan, Jinyue
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi. KTH.
    Numerical investigations on outdoor thermal comfort for built environment: Case study of a Northwest campus in China2019Ingår i: Energy Procedia, Elsevier Ltd , 2019, Vol. 158, s. 6557-6563Konferensbidrag (Refereegranskat)
    Abstract [en]

    Outdoor thermal comfort has been receiving more and more attentions due to the increased demand of outdoor activities during last decades. People require good thermal comfort when they are exposed to the outdoor thermal environment. However, the natural environment is severely suffering from the pollution of air, water as well as the extremely hot weather. Therefore, construction of ecological living environment is of great importance. To evaluate and improve the built environment, a campus area located in Northwest China was selected. Numerical simulations based on the software ENVI-met V4.0 were conducted and the effect of growing plants upon the outdoor thermal comfort was analyzed. Numerical results were compared using different thermal Indexes: Physiological Equivalent Temperature (PET) and Universal Thermal Climate Index (UTCI). Results demonstrated that UTCI gave a lower prediction than that of PET and was more suitable for evaluating the outdoor thermal comfort. Growing trees can significantly reduce the uncomfortable hours during hot summer but the improvement will reach the limitation after growing amount of trees.

  • 322.
    Lijing, Zhu
    et al.
    China Univ Petr, Acad China Energy Strategy, Peoples R China.
    Huihui, Lu
    China Univ Petr, Acad China Energy Strategy, Peoples R China.
    Qi, Zhang
    China Univ Petr, Acad China Energy Strategy, Peoples R China.
    LI, Hailong
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Xunzhang, Pan
    China Univ Petr, Acad China Energy Strategy, Peoples R China.
    Ge, Wang
    China Univ Petr, Acad China Energy Strategy, Peoples R China.
    Yan, Li
    China Univ Petr, Acad China Energy Strategy, Peoples R China.
    Application of Crowdfunding on the Financing of EV's Charging Piles2016Ingår i: CLEAN ENERGY FOR CLEAN CITY: CUE 2016 - APPLIED ENERGY SYMPOSIUM AND FORUM: LOW-CARBON CITIES AND URBAN ENERGY SYSTEMS, 2016, s. 336-341Konferensbidrag (Refereegranskat)
    Abstract [en]

    The market penetration of electric vehicle is subject to the capacity of charging facility greatly, however the development of charging facility is influenced by the economic incentives. In this study, the crowdfunding method is applied for financing the construction of electric vehicle (EV) charging piles, and its advantages was focused and proved. A three-stage sequential game model was developed considering power grid, infrastructure operators and crowdfunders to analyze the performance of crowdfunding in charging pile construction. The result shows that crowdfunding can increase charging piles construction amount by 70% and crowdfunding's promoting effect equals the effect of supplying 40% subsidy for construction fee. Thus crowdfunding is a simple but efficient way to boost the penetration of charging piles.

  • 323. Lijing, Zhu
    et al.
    Qi, Zhang
    Huihui, Lu
    Li, Hailong
    Mälardalens högskola, Akademin för innovation, design och teknik. Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Yan, Li
    Benjamin, McLellan
    Xunzhang, Pan
    Study on crowdfunding’s promoting effect on the expansion of electric vehicle charging piles based on game theory analysis2017Ingår i: Applied Energy, ISSN 0306-2619, E-ISSN 1872-9118, Vol. 196, s. 238-248Artikel i tidskrift (Refereegranskat)
  • 324.
    Lin, H.
    et al.
    Institute of Thermal Science and Technology, Shandong University, Jinan,China.
    Liu, Y.
    Institute of Thermal Science and Technology, Shandong University, Jinan,China.
    Sun, Q.
    Institute of Thermal Science and Technology, Shandong University, Jinan,China.
    Xiong, R.
    Department of Vehicle Engineering, School of Mechanical Engineering, Beijing Institute of Technology, Beijing, China.
    Li, Hailong
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Wennersten, R.
    Institute of Thermal Science and Technology, Shandong University, Jinan,China.
    The impact of electric vehicle penetration and charging patterns on the management of energy hub: A multi-agent system simulation2018Ingår i: Applied Energy, ISSN 0306-2619, E-ISSN 1872-9118, Vol. 230, s. 189-206Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    In this paper, a multi-agent system (MAS) was developed to simulate the operation of an energy hub (EH) with different penetration rates (PRs) and various charging patterns of electric vehicle (EV). Three charging patterns, namely uncontrolled charging pattern (UCP), rapid charging pattern (RCP) and smart charging pattern (SCP), together with vehicle to grid (V2G), were simulated in the MAS. The EV penetration rates (EV-PRs), from 10% to 90% with a step of 20%, are considered in this study. Under the UCP, the peak load increases by 3.4–17.1% compared to the case without EVs, which is the reference case in this study. A main part of the increased electricity demand can be supplied by the gas turbine (GT) when the PR is lower, i.e. 71.7% under 10% PR and 37.4% under 50% PR. Under the SCP, the charging load of EVs is shifted to the valley period and thus the energy dispatch of the EH at 07:00–23:00 remain the same as that in the reference case. When V2G is considered, the electricity demand from the grid becomes the largest in all of the cases, e.g. the demand with 50% PR doubles the electricity demand in the reference case. However, the GT output decreases by 2.9–15.7% at 07:00–23:00 due to the effect of V2G. The variations in the EH's operation further raise the changes in energy cost, i.e. the electricity and cooling prices are lowered by 18.3% and 33.8% due to the availability of V2G and the heating and cooling prices increase by 3.5% and 4.3% under the UCP with the PR of 50%. Regarding the V2G capacity, near 39% of the EVs’ battery capacity can be discharged via V2G. In addition, the paper also produced a V2G potential line, which is an effective tool to provide the maximum potential of the EVs for peak shaving at any specific time.

  • 325.
    Lin, Haiyang
    et al.
    Shandong Univ, Inst Thermal Sci & Technol, Shandong, Peoples R China.
    Bian, Caiyun
    China Univ Petr, Acad Chinese Energy Strategy, Beijing, Peoples R China.
    Li, Hailong
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Sun, Qie
    Shandong Univ, Inst Thermal Sci & Technol, Shandong, Peoples R China.
    Wennersten, Ronald
    Shandong Univ, Inst Thermal Sci & Technol, Shandong, Peoples R China.
    Optimal Siting and Sizing of Public Charging Stations in Urban Area2018Ingår i: JOINT INTERNATIONAL CONFERENCE ON ENERGY, ECOLOGY AND ENVIRONMENT ICEEE 2018 AND ELECTRIC AND INTELLIGENT VEHICLES ICEIV 2018, DESTECH PUBLICATIONS, INC , 2018Konferensbidrag (Refereegranskat)
    Abstract [en]

    Electric Vehicles (EVs) have achieved a significant development because of the continuous technology revolution and policy supports in recent years, which leads to a larger demand of EV charging stations (EVCSs). Strategies about optimal siting and sizing of public EVCSs are urgently needed in order to further assist the development of EVs. This paper focus on the return of investments on EVCSs and proposes a Mixed Integer Linear Programming (MILP) model based on Geographic Information System (GIS) to identify the optimal location and size of EVCS in cities. Traffic flow data, aggregated charging profiles and land-use classifications are used as important inputs together with important constraints, are included in the MILP model with the objective function of maximizing the total profits of new charging stations. The effectiveness of the proposed method is then demonstrated by implementing a case study in Vasteras, Sweden.

  • 326.
    Lind, Philip
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik.
    A study of modelling the energy system of an ice rink sports facility: Modelling the heating and cooling of ABB arena syd and implementation of renewable energy sources using TRNSYS2018Självständigt arbete på avancerad nivå (masterexamen), 20 poäng / 30 hpStudentuppsats (Examensarbete)
    Abstract [en]

    Environmental issues are important challenges for today’s society. Lots of the energy used by humans comes from fossil energy sources resulting in the environmental threats. A considerable amount of this energy is used in the building sector. Industrial buildings and sports facilities are large users of energy and thus becomes very interesting in an optimization point of view. Modelling of the systems allows for cheap and effective optimizing of the energy usage and effectivity measures can be investigated and implemented. This study creates a model of the indoor ice rink arena of ABB arena syd in Västerås using TRNSYS as the main software for simulation. Focus is placed on the heating of the arena through heat pumps and district heating, and cooling of the ice in the arena using cooling machines. The effect of PV as well as a battery storage in the arena is also investigated as an effectiveness scenario. The results from the study revealed that it is possible to simulate the heating demand for the arena, accurately identifying the normal demand as well as the instances when the demand peaks and the magnitude of the peaks. It is also possible to simulate the cooling demand for the ice over extended time periods. However, this study could not identify the peaks for cooling demand. It is also beneficial for the system to install PV, but not a battery storage. With current price levels for electricity it is however not a very beneficial deal. With higher electricity prices the investment is preferable. The study also concludes that TRNSYS can be used for modelling an ice rink sports arena, however it leaves room for improvement on that aspect.

  • 327.
    Lindberg, Carl-Fredrik
    et al.
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi. ABB Corp Res, Västerås, Sweden..
    Tan, SieTing
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi. Univ Teknol Malaysia, Johor, Malaysia.
    Yan, JinYue
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Starfelt, Fredrik
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi. MälarEnergi, Västerås, Sweden.
    Key performance indicators improve industrial performance2015Ingår i: Energy Procedia, ISSN 1876-6102, E-ISSN 1876-6102, Vol. 75, s. 1785-1790Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Key Performance Indicators (KPIs) are important for monitoring the performance in the industry. They can be used to identify poor performance and the improvement potential. KPIs can be defined for individual equipment, sub-processes, and whole plants. Different types of performances can be measured by KPIs, for example energy, raw-material, control & operation, maintenance, etc. Benchmarking KPIs with KPIs from similar equipment and plants is one method of identifying poor performing areas and estimating improvement potential. Actions for performance improvements can then be developed, prioritized and implemented based on the KPIs and the benchmarking results. An alternative to benchmarking, which is described in this paper, is to identify the process signals that are strongest correlated with the KPI and then change these process signals in the direction that improves the KPI. This method has been applied to data from a combined heat and power plant and a suggestion are given on how to improve boiler efficiency. 

  • 328.
    Lindhult, Erik
    et al.
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Campillo, Javier
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Dahlquist, Erik
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Read, S.
    TU Delft, Delft, Netherlands.
    Innovation capabilities and challenges for energy smart development in medium sized European cities2016Ingår i: Energy Procedia, ISSN 1876-6102, E-ISSN 1876-6102, nr 88, s. 205-211Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Transition towards becoming Energy smart city integrating different areas of energy production, distribution and use in a community requires a spectrum of capabilities. The paper reports on findings from the EU planning project PLEEC, involving six medium sized European cities. The purpose of the paper is to describe innovation capabilities and challenges in the complex, systemic innovation journey of cities in the transition to sustainability. A case of implementing an innovative project for electrical vehicles in Eskilstuna is presented illustrating both technological potentials and innovation challenges.

  • 329.
    Lingfors, D.
    et al.
    Department of Engineering Sciences, Uppsala University, Uppsala, Sweden.
    Widén, J.
    Department of Engineering Sciences, Uppsala University, Uppsala, Sweden.
    Marklund, J.
    Department of Engineering Sciences, Uppsala University, Uppsala, Sweden.
    Boork, M.
    SP Technical Research, Institute of Sweden, Uppsala, Sweden.
    Larsson, David
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Photovoltaics in Swedish agriculture: Technical potential, grid integration and profitability2015Ingår i: ISES Solar World Congress 2015, Conference Proceedings, International Solar Energy Society , 2015, s. 259-267Konferensbidrag (Refereegranskat)
    Abstract [en]

    This paper investigates the realizable potential for photovoltaic (PV) systems in Swedish agriculture. Marginal lands and available building areas for PV systems are quantified, and factors limiting the potential are analyzed. It is shown that the potential for PV in Swedish agriculture is high, but what is fully realizable is limited by the capacity of the rural power grid. A case study in the rural municipality of Herrljunga was conducted and scaled to national level. The study shows that the risk of surges in the medium voltage grid (10 kV) in rural areas are small in case where all roof surfaces with an annual solar irradiance of over 950 kWh/m2 are used for solar power. The total electricity production from the Swedish agriculture, if all roof areas with this irradiance level were used, is estimated to 4 TWh annually. With solar power on all roof surfaces with an annual irradiance of at least 900 kWh per m2 problems with voltage rise and overloads in the electricity grid might occur. The electrical grid capacities thus substantially limit how much solar power can be installed. Our results also show that the profitability limits the potential to 0.2 TWh on a national level, but that it could increase if more optimistic economic conditions are assumed.

  • 330.
    Liu, J.
    et al.
    China Institute of Water Resources and Hydropower Research, Beijing, China.
    Chen, S.
    China Institute of Water Resources and Hydropower Research, Beijing, China.
    Wang, H.
    China Institute of Water Resources and Hydropower Research, Beijing, China.
    Campana, Pietro Elia
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Yan, Jinyue
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Evolution of China's urban energy consumption structure-a case study in Beijing2016Ingår i: Energy Procedia, ISSN 1876-6102, E-ISSN 1876-6102, Vol. 88, s. 88-93Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    China is a coal-based energy consuming country. The proportion of coal is up to 70% in the energy consumption structure in 1990s. In the past 20 years, driven by energy saving policy, China's energy consumption structure has undergone great changes, especially in urban areas. This paper explores the evolution of energy-use structure at the national level and the level of Beijing City in China. Four major energy sources were considered, including coal, oil, natural gas and electricity. The dataset was collected from 1990 to 2012. The results show that the proportion of coal consumption decreased by approximately 20% from 1990 to 2012 at the national level in compare with nearly 50% at the level of Beijing City. Furthermore, the proportion of natural gas consumption and other clean energies rose. In Beijing the natural gas and other clean energies account for over 60% of the total energy in 2012, which played an important role in improving the local environment.

  • 331.
    Liu, J.
    et al.
    South University of Science and Technology of China, Shenzhen, China.
    Mao, G.
    South University of Science and Technology of China, Shenzhen, China.
    Hoekstra, A.Y.
    University of Twente, Netherlands.
    Wang, D.
    China Institute of Water Resources and Hydropower Research, Beijing, China.
    Wang, J.
    China Institute of Water Resources and Hydropower Research, Beijing, China.
    Zheng, C.
    South University of Science and Technology of China, Shenzhen, China.
    van Vliet, M.T.H
    Wageningen University, Netherlands.
    Wu, M.
    Argonne National Laboratory, United States.
    Ruddell, B.
    Northern Arizona University, US.
    Yan, Jinyue
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi. Royal Institute of Technology, Stockholm, Sweden.
    Managing the energy-water-food nexus for sustainable development2018Ingår i: Applied Energy, ISSN 0306-2619, E-ISSN 1872-9118, Vol. 210, s. 377-381Artikel i tidskrift (Refereegranskat)
  • 332.
    Liu, L.
    et al.
    Shandong University, China.
    Liu, D.
    Shandong University, China.
    Sun, Q.
    Shandong University, China.
    Li, Hailong
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Wennersten, R.
    Shandong University, China.
    Forecasting Power Output of Photovoltaic System Using A BP Network Method2017Ingår i: Energy Procedia, ISSN 1876-6102, E-ISSN 1876-6102, Vol. 142, s. 780-786Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The characteristics of intermittent and stochastic of solar energy has brought great challenges to power grid system in terms of operation and regulation. Power forecasting is an important factor for optimal schedule of power grid system and assessing the working performance of PV systems. In order to forecast the power output of a PV system located in Ashland at 24-hour-ahead for higher efficiency, a back propagation (BP) neural network model is proposed. Before designing the model, correlation analysis is done to investigate the relationship between power output and solar irradiance and ambient temperature, which are key parameters affecting the power output of PV systems. Based on a correlation analysis, the model admitted the following input parameters: hourly solar radiation intensity, the highest, the lowest daily and the average daily temperature, and hourly power output of the PV system. The output of the model is the forecasted PV power output 24 hours ahead. Based on the datasets, the neural network is trained to improve its accuracy. The best performance is obtained with the BP neural network structure of 28-20-11. The analysis of the error indicator MAPE shows that the proposed model has great accuracy and efficiency for forecasting the power output of photovoltaic systems.

  • 333.
    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.

  • 334.
    Liu, M.
    et al.
    School of Environmental Science and Engineering, Tianjin University, China.
    Zhu, C.
    School of Environmental Science and Engineering, Tianjin University, China.
    Zhang, H.
    School of Environmental Science and Engineering, Tianjin University, China.
    Zheng, W.
    School of Environmental Science and Engineering, Tianjin University, China.
    You, S.
    School of Environmental Science and Engineering, Tianjin University, China.
    Campana, Pietro Elia
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi. KTH.
    Yan, Jinyue
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    The environment and energy consumption of a subway tunnel by the influence of piston wind2019Ingår i: Applied Energy, ISSN 0306-2619, E-ISSN 1872-9118, Vol. 246, s. 11-23Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    With the flourishing development of the subway construction, it becomes increasingly urgent to improve the subway tunnel environment and reduce the energy consumption of the tunnel ventilation system. The tunnel environment is significantly affected by the piston wind, which is influenced by the train speed. In this paper, a three-dimensional computational model of a subway tunnel is developed and validated through experiments. The model is used to study the carbon dioxide concentration and thermal environment of the subway tunnel. The optimal train speed is proposed with the aim to minimize the volume of mechanical supply air and to optimize the carbon dioxide concentration and thermal environment of the tunnel. In parallel with the considerations of tunnel environment, the subways in 25 cities of China are analyzed to study the energy conservation of the tunnel ventilation system by making full use of piston wind. The results indicate that the optimal train speed is 30 m/s based on the carbon dioxide concentration and thermal environment. The effective utilization of the piston wind can reduce 13%∼32% of the energy consumption for tunnel ventilation. The calculation method of the optimal train speed developed in this paper is also applicable to ordinary railway tunnels and high-speed railway tunnels.

  • 335.
    Liu, S.
    et al.
    Tianjin University of Commerce, China.
    Sun, Z.
    Tianjin University of Commerce, China.
    Li, Hailong
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Dai, B.
    Tianjin University of Commerce, China.
    Chen, Y.
    R&D Center, VECK (Tianjin) Co. Ltd, Tianjin, China.
    Thermodynamic analysis of CO2 transcritical two-stage compression refrigeration cycle systems with expanders2017Ingår i: HKIE Transactions Hong Kong Institution of Engineers, ISSN 1023-697X, Vol. 24, nr 2, s. 70-77Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The key to improving the efficiency of carbon dioxide (CO2) transcritical refrigeration systems is to select an appropriate two-stage compression system. In this study, the thermodynamic performance of six different CO2 transcritical two-stage refrigeration systems with expanders is compared. The design parameters are analysed to determine their respective impacts on the system coefficient of performance (COP) in order to ascertain which system configuration produces the maximum system COP. It is concluded that the system with a two-stage expander and incomplete intercooling has great advantages in terms of performance and equipment selection for the high-pressure stage in certain circumstances. Under the given conditions, the design parameters including the evaporating temperature, the condensing temperature, the compressor efficiency of the high-pressure stage, and the compressor efficiency of the low-pressure stage impact on the system performance. It should be noted that the gas cooler outlet temperature and the compressor efficiency of the low-pressure stage are the major factors which affect the efficiency of the system; thus, the system design and equipment selection should minimise the gas cooler outlet temperature and select a high-efficiency compressor for the low-pressure stage to ensure efficient and safe operation. 

  • 336.
    Liu, Shengchun
    et al.
    Tianjin University of Commerce.
    Li, Zheng
    Tianjin University of Commerce.
    Dai, Baomin
    Tianjin University of Commerce.
    Zhong, Zhifeng
    Tianjin University of Commerce.
    Li, Hailong
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Song, Mengjie
    Sun, Zhili
    Energetic, economic and environmental analysis of air source transcritical CO2 heat pump system for residential heating in China2019Ingår i: Applied Thermal Engineering, ISSN 1359-4311, E-ISSN 1873-5606, Vol. 148, s. 1425-1439Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Using air source heat pump system for residential heating is a practical way to replace coal-fired boiler in China to alleviate the haze problem, and CO2 is a promising candidate to replace hydrochlorofluorocarbon (HCFC) or hydrofluorocarbon (HFCs) charged into the system. A mathematical model is developed to comprehensively evaluate the energetic, economical and environmental performances of CO2 heat pump system compared with other three traditional heating methods. The results indicate that the primary energy ratio of CO2 heat pump is the highest and it is a rational way to utilize renewable energy with the renewable energy contribution ratio of 0.60–0.69. The initial capital cost of CO2 heat pump is much higher due to the dominant compressor cost. The emission of CO2 heat pump is lower than that of coal-fired boiler at seasonal performance factor above 2.44. The initial and operation cost can be gradually reduced with the mass production and energy efficiency improvement of CO2 heat pump. It is believe that air source CO2 heat pump system can be employed for home heating in China, especial for the hot summer and cold winter region.

  • 337.
    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.

  • 338.
    Liu, Y.
    et al.
    Chinese Academy of Sciences, Guangzhou, China.
    Chen, L.
    Chinese Academy of Sciences, Guangzhou, China.
    Wang, T.
    Chinese Academy of Sciences, Guangzhou, China.
    Zhang, Q.
    Chinese Academy of Sciences, Guangzhou, China.
    Wang, C.
    Chinese Academy of Sciences, Guangzhou, China.
    Yan, Jinyue
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi. Royal Institute of Technology, Stockholm, Sweden.
    Ma, L.
    Chinese Academy of Sciences, Guangzhou, China.
    One-Pot Catalytic Conversion of Raw Lignocellulosic Biomass into Gasoline Alkanes and Chemicals over LiTaMoO6 and Ru/C in Aqueous Phosphoric Acid2015Ingår i: ACS Sustainable Chemistry and Engineering, ISSN 2168-0485, Vol. 3, nr 8, s. 1745-1755Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Lignocellulosic biomass is a renewable feedstock that has the potential to replace the diminishing fossil fuels. Herein, we reported the simultaneous conversion of cellulose, hemicellulose and lignin from raw biomass into gasoline alkanes (hexanes and pentanes) and monophenols and related hydrocarbons over layered LiTaMoO<inf>6</inf> and Ru/C in aqueous phosphoric acid medium. Specifically, gasoline alkanes were directly yielded from the carbohydrate components, based on hemicellulose and cellulose, and the total yield could be up to 82.4%. Notably, the lignin fraction could also be transformed into monophenols, related alcohols and hydrocarbons by the one-pot reaction. It suggested that the hydrocracking of monophenol fraction could be performed in this catalytic system. The total yield of volatile products was 53% based on the lignin fraction. In this paper, the influences of phosphoric acid concentration, substrate ash and the amino acids derived from the biogenic impurities were investigated and different raw biomass substrates were tested. Furthermore, the catalysts could be reused for several runs to convert raw biomass without pretreatment.

  • 339.
    Liu, Z.
    et al.
    Resnick Sustainability Institute, California Institute of Technology, Pasadena, CA, United States.
    Feng, K.
    Department of Geographical Sciences, University of Maryland, College Park, MD, United States.
    Davis, S. J.
    Department of Earth System Science, University of California, Irvine, United States.
    Guan, D.
    Tyndall Centre for Climate Change Research, School of International Development, University of East Anglia, Norwich, United Kingdom.
    Chen, B.
    School of Environment, Beijing Normal University, Beijing, China.
    Hubacek, K.
    Royal Institute of Technology (KTH), Stockholm, Sweden.
    Yan, Jinyue
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi. Royal Institute of Technology (KTH), Stockholm, Sweden.
    Understanding the energy consumption and greenhouse gas emissions and the implication for achieving climate change mitigation targets2016Ingår i: Applied Energy, ISSN 0306-2619, E-ISSN 1872-9118, Vol. 184, s. 737-741Artikel i tidskrift (Refereegranskat)
  • 340.
    Liu, Z.
    et al.
    Qingdao University of Science and Technology, Qingdao, 266061, China.
    Yang, X.
    Xi'an Jiaotong University, Xi'an, 710049, China.
    Jia, W.
    Qingdao University of Science and Technology, Qingdao, 266061, China.
    Li, Hailong
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Justification of CO2 as the working fluid for a compressed gas energy storage system: A thermodynamic and economic study2020Ingår i: Journal of Energy Storage, E-ISSN 2352-152X, Vol. 27, artikel-id 101132Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The compressed carbon dioxide (CO2) energy storage (CCES) system has been attracting more and more attentions in recent years. The CCES system leads the way of green solutions to accommodating the intermittency of renewable power generation systems in a large-scale energy storage pattern. Particularly, the usage of CO2 as the working medium for CCES successfully offers a green solution to massive carbon capture and storage. This paper aims to further analyze the applicability and feasibility of a novel CCES system with the merit of efficiently and economically utilizing pressure energy and thermal energy. Thermodynamic and cost evaluation on the energy conversion cycle were carried out. Genetic algorithm was employed to perform multi-objective optimization on the novel energy conversion cycle with thermal energy storage towards maximizing exergy efficiency and economic profits. Results reveal that the net output power monotonously increases with turbine inlet temperature, but the unit product cost monotonously decreases with turbine inlet temperature. The multi-objective optimization recommends a 60.5% for the overall exergy efficiency and 0.23 $/kWh for the unit product cost. Moreover, scattered distribution of decision variables suggests always a higher outlet pressure for compressor. 

  • 341.
    Liu, ZY
    et al.
    Tianjin Univ.
    Zhao, Li
    Tianjin Univ.
    Zhao, Xuezheng
    Tianjin Univ.
    Li, Hailong
    Mälardalens högskola, Akademin för hållbar samhälls- och teknikutveckling.
    The occurrence of pinch point and its effects on the performance of high temperature heat pump2012Ingår i: Applied Energy, ISSN 0306-2619, E-ISSN 1872-9118, Vol. 97, nr SI, s. 869-875Artikel i tidskrift (Refereegranskat)
    Abstract [en]

     Zeotropic mixtures are popular alternatives to chlorofluorocarbons (CFCs) and hydrochlorofluorocarbons (HCFCs) in the high temperature heat pump system. Zeotropic mixtures exhibit two major characteristics during phase change: temperature gliding and a nonlinear relationship between temperature and enthalpy. The theory proposed by Venkatarathnam that the nonlinear relationship between temperature and enthalpy in the two phase region for zeotropic mixtures can cause pinch points were verified experimentally. Results also show that the variations of the maximum temperature difference and the minimum temperature difference change the mean temperature difference in the same way, and further change the exergy loss in the same way. Therefore, when selecting zeotropic mixtures as working fluids in the high temperature heat pump, it is of great importance to check the pinch points occurring in condenser and evaporator. The zeotropic mixture that has a smaller maximum temperature difference in condenser and a smaller minimum temperature difference in evaporator can give a higher COP.

  • 342.
    Lu, H.
    et al.
    School of Mechanical and Power Engineering, East China University of Science and Technology, Shanghai, China.
    Yu, X.
    School of Mechanical and Power Engineering, East China University of Science and Technology, Shanghai, China.
    Li, Hailong
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Schwede, Sebastian
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Tu, S. -T
    School of Mechanical and Power Engineering, East China University of Science and Technology, Shanghai, China.
    Accurately measurement and efficiently recovery of ionic liquid in energy utilization of microalgae2019Ingår i: Energy Procedia, Elsevier Ltd , 2019, Vol. 158, s. 1337-1341Konferensbidrag (Refereegranskat)
    Abstract [en]

    Chlorella vulgais, a kind of micro-alagae, is an attracting feedstock for bioenergy production, such as biodiesel and biogas. But its tough cell wall structure is the main obstacle to efficiently extracting lipids and other biomass. Ionic liquid (IL) can be used to hydrolyze its cell-wall. However, due to its high cost and toxicity, it is important to recover IL as much as possible. Therefore, a method that can accurately measure the content of ILs, is urgently needed. In this work, two common methods that are used to measure the content of ILs: equimolar titration method and ultraviolet absorbance spectra were compared. The results show that equimolar titration method is not available for trace quantity analysis of ionic liquids as the endpoint of titration is hard to be identified at low IL content (<10 mg/L); while UV absorbance spectra method can be used at low IL contents, whereas, it may result in big deviations. To further improve the accuracy of UV absorbance spectra method, concentrating the sample could be a potential solution.

  • 343.
    Lundh, M.
    et al.
    Mälardalens högskola, Akademin för hållbar samhälls- och teknikutveckling.
    Vassileva, Iana
    Mälardalens högskola, Akademin för hållbar samhälls- och teknikutveckling.
    Dahlquist, Erik
    Mälardalens högskola, Akademin för hållbar samhälls- och teknikutveckling.
    Wäckelgård, E.
    Comparison between hot water measurements and modelled profiles for Swedish households2008Konferensbidrag (Refereegranskat)
  • 344.
    Lundström, Lukas
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi. Eskilstuna Kommunfastighet, Eskilstuna, Sweden.
    Adaptive Weather Correction of Energy Consumption Data2017Ingår i: Energy Procedia, Elsevier Ltd , 2017, s. 3397-3402Konferensbidrag (Refereegranskat)
    Abstract [en]

    A framework for adaptive weather correction of energy consumption data is presented. The procedure is conducted in two steps: I) a regression model is trained on a building's recent historical energy consumption, weather and calendar data; II) energy consumption is predicted by using long term weather data as input to the trained model. Thus the buildings long term energy consumption is obtained, from which the building's expected (alias normalised or weather corrected) yearly energy consumption is derived. For older Swedish residential buildings, the proposed regression method matches traditional heating degree days method in accuracy. But for low energy and near zero energy buildings the regression method is more accurate, especially for years of extreme weather and for building with more complex installations such as heat pumps or solar thermal panels. The main benefit of the developed weather correction method is that it adapts to the data, therefore most buildings (or any kinds of weather dependent processes) can be weather corrected in an automated way. © 2017 The Authors. Published by Elsevier Ltd.

  • 345.
    Lundström, Lukas
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Heat demand profiles of buildings' energy conservation measures and their impact on renewable and resource efficient district heating systems2016Licentiatavhandling, sammanläggning (Övrigt vetenskapligt)
    Abstract [en]

    Increased energy performance of the building stock of European Union is seen as an important measure towards mitigating climate change, increasing resource utilisation efficiency and energy supply security. Whether to improve the supply-side, the demand-side or both is an open issue. This conflict is even more apparent in countries such as Sweden with a high penetration of district heating (DH). Many Swedish DH systems have high share of secondary energy resources such as forest industry residuals, waste material incineration and waste heat; and resource efficient cogeneration of electricity in combined heat and power (CHP) plants. When implementing an energy conservation measure (ECM) in a DH connected building stock, it will affect the operation of the whole DH system. If there are CHP plants and the cogeneration of electricity decreases due to an ECM, and this electricity is valued higher than the fuel savings, the consequences of the ECM would be negative. 

    These complex relationships are investigated by conducting a case study on the Eskilstuna DH system, a renewable energy supply system with relatively high share of cogenerated electricity. Heat demand profiles of ECMs are determined by building energy simulation, using recently deep energy retrofitted multifamily buildings of the “Million Programme”-era in Eskilstuna as model basis. How implementing ECMs impact on the DH system’s heat and electricity production under different electricity revenue scenarios has been computed and evaluated in terms of resource efficiency and CO2 emissions. 

    The results show that different ECMs in the buildings impact differently on the DH system. Measures such as improved insulation level of the building’s envelope, that decrease the heat demand’s dependence to outdoor temperature, increase the amount of cogenerated electricity. While measures such as thermal solar panels, which save heat during summer, affects the absolute amount of cogenerated electricity negatively. Revenues from cogenerated electricity influence the amount of cost-effectively produced electricity much more than the impact from ECMs. Environmental benefits of the ECMs, measured in CO2 emissions and primary energy consumption, are quite small in DH systems that have high share of forest residual fuels and electricity cogeneration. The consequences can even be negative if ECMs lead to increased need of imported electricity that is produced resource inefficiently or/and by fossil fuels. However, all studied ECMs increase the relative amount of cogenerated electricity, the ratio between amount of cogenerated electricity and the heat load. This implied that all ECMs increase the overall efficiency of the Eskilstuna DH system.

  • 346.
    Lundström, Lukas
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Mesoscale Climate Datasets for Building Modelling and Simulation2016Ingår i: CLIMA 2016 - proceedings of the 12th REHVA World Congress: volume 9. Aalborg: Aalborg University, Department of Civil Engineering. / [ed] Heiselberg, Per Kvols, Aalborg, 2016, Vol. 9, artikel-id 659Konferensbidrag (Refereegranskat)
    Abstract [en]

    This work presents a method to make use of gridded historical mesoscale datasets for energy and hygrothermal building modelling and simulation purposes by transforming, merging and formatting them into time series. The main result of this work is a web tool, https://rokka.shinyapps.io/shinyweatherdata, allowing users to create actual climate dataset for any location in North Europe in file formats used by common building simulations tools. A review is conducted on freely available gridded mesoscale datasets/model systems for north Europe: the modelling systems MESAN and STRÅNG currently used as data source for the developed web tool as well as the SARAH model system and MESAN/MESCAN reanalysis datasets.

  • 347.
    Lundström, Lukas
    et al.
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi. Eskilstuna Kommunfastighet AB, Eskilstuna, Sweden.
    Akander, J.
    Division of Building, Energy and Environment Technology, Department of Technology and Environment, University of Gävle, Sweden.
    Zambrano, Jesus
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Development of a space heating model suitable for the automated model generation of existing multifamily buildings—a case study in Nordic climate2019Ingår i: Energies, ISSN 1996-1073, E-ISSN 1996-1073, Vol. 12, nr 3, artikel-id 485Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Building energy performance modeling is essential for energy planning, management, and efficiency. This paper presents a space heating model suitable for auto-generating baseline models of existing multifamily buildings. Required data and parameter input are kept within such a level of detail that baseline models can be auto-generated from, and calibrated by, publicly accessible data sources. The proposed modeling framework consists of a thermal network, a typical hydronic radiator heating system, a simulation procedure, and data handling procedures. The thermal network is a lumped and simplified version of the ISO 52016-1:2017 standard. The data handling consists of procedures to acquire and make use of satellite-based solar radiation data, meteorological reanalysis data (air temperature, ground temperature, wind, albedo, and thermal radiation), and pre-processing procedures of boundary conditions to account for impact from shading objects, window blinds, wind- and stack-driven air leakage, and variable exterior surface heat transfer coefficients. The proposed model was compared with simulations conducted with the detailed building energy simulation software IDA ICE. The results show that the proposed model is able to accurately reproduce hourly energy use for space heating, indoor temperature, and operative temperature patterns obtained from the IDA ICE simulations. Thus, the proposed model can be expected to be able to model space heating, provided by hydronic heating systems, of existing buildings to a similar degree of confidence as established simulation software. Compared to IDA ICE, the developed model required one-thousandth of computation time for a full-year simulation of building model consisting of a single thermal zone. The fast computation time enables the use of the developed model for computation time sensitive applications, such as Monte-Carlo-based calibration methods. 

  • 348.
    Lundström, Lukas
    et al.
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi. Eskilstuna Energy and Envirorment, Eskilstuna; Eskilstuna kommunfastigheter, Eskilstuna .
    Dahlquist, Erik
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Wallin, Fredrik
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Helgesson, Jan
    Eskilstuna kommunfastigheter, Eskilstuna .
    Björklund, Ulf
    Eskilstuna Energy and Environment, Eskilstuna .
    Impact on carbon dioxide emissions from energy conservation within Swedish district heating networks2014Ingår i: Energy Procedia, ISSN 1876-6102, E-ISSN 1876-6102, Vol. 61, s. 2132-2136Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The 100 largest Swedish district heating (DH)-networks were studied on how DH conservation measures impacts CO2-emission rates taking both direct and indirect (i.e. displaced electricity) emissions into account, applying six different methods for the indirect emissions assessment. When the marginal electricity approach is applied on low CO2-emitting DH-networks with a high share of cogenerated electricity, it resulted in assessments that imply that DH conservation leads to higher CO2 emissions. This was not the case with the efficiency method.

  • 349.
    Lundström, Lukas
    et al.
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Wallin, Fredrik
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Heat demand profiles of energy conservation measures in buildings and their impact on a district heating system2016Ingår i: Applied Energy, ISSN 0306-2619, E-ISSN 1872-9118, Vol. 161, s. 290-299Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    This study highlights the forthcoming problem with diminishing environmental benefits from heat demand reducing energy conservation measures (ECM) of buildings within district heating systems (DHS), as the supply side is becoming "greener" and more primary energy efficient. In this study heat demand profiles and annual electricity-to-heat factors of ECMs in buildings are computed and their impact on system efficiency and greenhouse gas emissions of a Swedish biomass fuelled and combined heat and power utilising DHS are assessed. A weather normalising method for the DHS heat load is developed, combining segmented multivariable linear regressions with typical meteorological year weather data to enable the DHS model and the buildings model to work under the same weather conditions. Improving the buildings' envelope insulation level and thereby levelling out the DHS heat load curve reduces greenhouse gas emissions and improves primary energy efficiency. Reducing household electricity use proves to be highly beneficial, partly because it increases heat demand, allowing for more cogeneration of electricity. However the other ECMs considered may cause increased greenhouse gas emissions, mainly because of their adverse impact on the cogeneration of electricity. If biomass fuels are considered as residuals, and thus assigned low primary energy factors, primary energy efficiency decreases when implementing ECMs that lower heat demand.

  • 350.
    Luyao, Liu
    et al.
    Shandong University, Jinan, China.
    Qinxing, Wang
    Shandong University, Jinan, China.
    Haiyang, Lin
    Shandong University, Jinan, China.
    Li, Hailong
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Qie, Sun
    Shandong University, Jinan, China.
    Wennersten, Roland
    Shandong University, Jinan, China.
    Power Generation Efficiency and Prospects of Floating Photovoltaic Systems2017Ingår i: Energy Procedia, ISSN 1876-6102, E-ISSN 1876-6102, Vol. 105, s. 1136-1142Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    At present, China's economic and social development is restricted by many factors, such as environmental pollution and the supply of energy, land resources and water resources. Compared with traditional terrestrial photovoltaic (PV) systems, floating PV systems can save a lot of land and water resources and obtain higher power generation efficiency. Although the academics have reached a general consensus about the advantages of floating systems, very few in-depth studies focus on the specifications of floating PV systems. Therefore, this study first discusses the development of PV technology, then studies the power generation efficiency of floating PV systems, and finally comprehensively analyzes the advantages and potential of floating PV systems in China.

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