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  • 51.
    Kalai, D. Y.
    et al.
    University of Stavanger, Stavanger, Norway.
    Stangeland, K.
    University of Stavanger, Stavanger, Norway.
    Li, Hailong
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Yu, Z.
    University of Stavanger, Stavanger, Norway.
    The effect of la on the hydrotalcite derived Ni catalysts for dry reforming of methane2017Inngår i: Energy Procedia, ISSN 1876-6102, E-ISSN 1876-6102, Vol. 142, s. 3721-3726Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    A series of 20Ni-Mg-Al hydrotalcite-like (HT) precursors were prepared to study the influence of lanthanum (La) on the catalytic activity of the catalysts in the dry reforming of methane (DRM). The catalysts were characterized by N2 adsorption-desorption, X-ray diffraction (XRD) and temperature-programmed reduction (TPR). All catalysts presented ordered mesoporous structures with a large specific surface area. XRD confirmed the presence of HT structure for all of the precursors while the La promotion resulted in an additional phase of Lanthanum carbonate hydroxide. TPR study showed larger reduction degree for the catalysts but also reduction peaks that are shifted to higher temperatures. DRM reactions at 600 and 750°C revealed that the DRM activity was increased by the addition of La, while the stability of the catalysts was reduced at 600°C. 

  • 52.
    Li, Hailong
    et al.
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi. Ningbo RX New Materials Tch. Co. Ltd., China; KTH, Stockholm, Sweden.
    Campana, Pietro Elia
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi. Ningbo RX New Materials Tch. Co. Ltd., China.
    Berretta, Sara
    Tan, Yuting
    Ningbo RX New Materials Tch. Co. Ltd., China; KTH, Stockholm, Sweden.
    Yan, Jinyue
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi. KTH, Stockholm, Sweden.
    Dynamic performance of the standalone wind power driven heat pump2016Inngår i: Energy Procedia, ISSN 1876-6102, E-ISSN 1876-6102, Vol. 103, s. 40-45Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Reducing energy consumption and increasing use of renewable energy in the building sector is crucial to the mitigationof climate change. Wind power driven heat pumps have been considered as a sustainable measure to supply heat forthe detached houses, especially those that even don’t have access to the grid. This work is to investigate the dynamic performance of a heat pump system directly driven by a wind turbine. The heat demand of a detached single familyhouse was simulated in details. To handle the intermittent characteristic of wind power, an electric energy storage system was included. According to the simulations, the wind turbine itself cannot always satisfy the electricity demand of the heat pump, and a larger size of the energy storage system can reduce the probability of load loss. However, it is different from the energy storage system that increasing the capacity of wind turbines may increase the probability of load loss instead, due to the different start-up speed of wind turbines. In order to maximize the system benefit, the capacity of the wind turbine and the size of the energy storage system should be optimized simultaneously based on dynamic simulations.

  • 53.
    Li, Hailong
    et al.
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi. Ningbo RX New Materials Tch. Co. Ltd., Ningbo, China.
    Campana, Pietro Elia
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi. Ningbo RX New Materials Tch. Co. Ltd., Ningbo, China.
    Tan, Y.
    Ningbo RX New Materials Tch. Co. Ltd., Ningbo, China.
    Yan, Jinyue
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi. Department of Chemical Engineering, KTH Royal Institute of Technology, Stockholm, Sweden.
    Feasibility study about using a stand-alone wind power driven heat pump for space heating2018Inngår i: Applied Energy, ISSN 0306-2619, E-ISSN 1872-9118, Vol. 228, s. 1486-1498Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Reducing energy consumption and increasing the use of renewable energy in the building sector are crucial to the mitigation of climate change. Wind power driven heat pumps have been considered as a sustainable measure to supply heat to the detached houses, especially those that even do not have access to the electricity grid. This work is to investigate the dynamic performance of a heat pump system driven by wind turbine through dynamic simulations. In order to understand the influence on the thermal comfort, which is the primary purpose of space heating, the variation of indoor temperature has been simulated in details. Results show that the wind turbine is not able to provide the electricity required by the heat pump during the heating season due to the intermittent characteristic of wind power. To improve the system performance, the influences of the capacity of wind turbine, the size of battery and the setpoint of indoor temperature were assessed. It is found that increasing the capacity of wind turbines is not necessary to reduce the loss of load probability; while on the contrary, increasing the size of battery can always reduce the loss of load probability. The setpoint temperature clearly affects the loss of load probability. A higher setpoint temperature results in a higher loss of thermal comfort probability. In addition, it is also found that the time interval used in the dynamic simulation has significant influence on the result. In order to have more accurate results, it is of great importance to choose a high resolution time step to capture the dynamic behaviour of the heat supply and its effect on the indoor temperature.

  • 54. Li, Hailong
    et al.
    Campana, Pietro Elia
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik.
    Yan, Jinyue
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik.
    Dynamic Modeling of a PV Pumping System with Special Consideration on Water Demand2012Konferansepaper (Fagfellevurdert)
  • 55.
    Li, Hailong
    et al.
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Daheem, Mehmood
    University of Stavanger, Norway.
    Thorin, Eva
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Zhixin, Yu
    University of Stavanger, Norway.
    Biomethane production via anaerobic digestion and biomass gasification2017Inngår i: Energy Procedia, ISSN 1876-6102, E-ISSN 1876-6102, Vol. 105, s. 1172-1177Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The transport sector accounts for the second biggest greenhouse gas emissionin the European Union (EU). In order to achieve the target of CO2 emission reduction there is a rapid growing interest in using biomethane as fuel for transport applications. Biomethane can be produced through anaerobic digestion or biomass gasification. Anaerobic digestion is a biochemical process. Since the raw gas contains approximately 65 vol% CH4 and 3 5vol%, an upgrading process is needed to remove CO2. Göteborg biomass gasification project (GoBiGas) is the world's first demonstration plant for large-scale production of biomethane through the gasification of forest residues. To achieve high purity CH4, a methanation process is required after gasification. This work compares these two technologies from the perspective of energy efficiency. Simulation results show that they have similar efficiencies: 62-64% for AE and ~65% for GoBiG.

  • 56.
    Li, Hailong
    et al.
    SINTEF Energy Research.
    Ditaranto, M
    SINTEF Energy Research.
    Berstad, D
    SINTEF Energy Research.
    Technologies for increasing CO2 concentration in exhaust gas from natural gas-fired power production with post-combustion, amine-based CO2 capture2011Inngår i: Energy, ISSN 0360-5442, E-ISSN 1873-6785, Vol. 36, nr 2, s. 1124-1133Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Enhanced CO2 concentration in exhaust gas is regarded as a potentially effective method to reduce thehigh electrical efficiency penalty caused by CO2 chemical absorption in post-combustion capturesystems. The present work evaluates the effect of increasing CO2 concentration in the exhaust gas of gasturbine based power plant by four different methods: exhaust gas recirculation (EGR), humidification(EvGT), supplementary firing (SFC) and external firing (EFC). Efforts have been focused on the impacts oncycle efficiency, combustion, gas turbine components, and cost. The results show that the combined cyclewith EGR has the capability to change the molar fraction of CO2 with the largest range, from 3.8 mol% toat least 10 mol%, and with the highest electrical efficiency. The EvGT cycle has relatively low additionalcost impact as it does not require any bottoming cycle. The externally fired method was found to have theminimum impacts on both combustion and turbomachinery.

  • 57.
    Li, Hailong
    et al.
    Mälardalens högskola, Akademin för hållbar samhälls- och teknikutveckling.
    Ditaranto, Mario
    SINTEF Energy Res,Trondheim, Norway.
    Yan, Jinyue
    Mälardalens högskola, Akademin för hållbar samhälls- och teknikutveckling.
    Carbon capture with low energy penalty: Supplementary fired natural gas combined cycles2012Inngår i: Applied Energy, ISSN 0306-2619, E-ISSN 1872-9118, Vol. 97, nr SI, s. 164-169Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Enhancing CO2 concentration in exhaust gas has been considered as a potentially effective method to reduce the penalty of electrical efficiency caused by CO2 chemical absorption in post-combustion carbon capture systems. Supplementary firing is an option that inherently has an increased CO2 concentration in the exhaust gas, albeit a relatively low electrical efficiency due to its increased mass flow of exhaust gas to treat and large temperature difference in heat recovery steam generator. This paper focuses on the methods that can improve the electrical efficiency of the supplementary fired combined cycles (SFCs) integrated with MEA-based CO2 capture. Three modifications have been evaluated: (I) integration of exhaust gas reheating, (II) integration of exhaust gas recirculation, and (III) integration of supercritical bottoming cycle. It is further showed that combining all three modifications results in a significant increase in electrical efficiency which is raised from 43.3% to 54.1% based on Lower Heating Value (LHV) of natural gas when compared to the original SFC. Compared with a conventional combined cycle with a subcritical bottoming cycle and without CO2 capture (56.7% of LHV), the efficiency penalty caused by CO2 capture is only 2.6% of LHV.

  • 58.
    Li, Hailong
    et al.
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi. Key Laboratory of Refrigeration Technology of Tianjin, Tianjin University of Commerce, Tianjin, 300134, China.
    Dong, B.
    Key Laboratory of Refrigeration Technology of Tianjin, Tianjin University of Commerce, Tianjin, 300134, China.
    Yu, Z.
    Department of Energy and Petroleum Engineering, University of Stavanger, Stavanger, 4036, Norway.
    Yan, Jinyue
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Zhu, K.
    Key Laboratory of Refrigeration Technology of Tianjin, Tianjin University of Commerce, Tianjin, 300134, China.
    Thermo-physical properties of CO2 mixtures and their impacts on CO2 capture, transport and storage: Progress since 20112019Inngår i: Applied Energy, ISSN 0306-2619, E-ISSN 1872-9118, Vol. 255, artikkel-id 113789Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The knowledge of accurate thermo-physical properties is crucial for the development and deployment of CO2 capture, transport and storage (CCS). The progress on the experimental data and theoretical models regarding thermo-physical properties of CO2 mixtures as well as the property impact on the design and operation of different CCS processes has been updated. The newly published experimental data since 2011 have been collected and reviewed based on which the new knowledge gaps regarding measurements have been identified. There have also been some advanced models proposed recently, which have shown good performances. The collected model performances don't show there exist a model that is superior to others; but they still provide a good guideline regarding model selection. However, developing more-complex models as the complexity may not necessarily improve the accuracy when empirical parameters were included and well-tuned. By comparing the importance of the properties and the accuracy of existing models, suggestions were given regarding the development of property models that should be prioritized. 

  • 59.
    Li, Hailong
    et al.
    Chemical Engineering and Technology/Energy Processes, Royal Institute of Technology.
    Flores, S.
    Chemical Engineering and Technology/Energy Processes, Royal Institute of Technology, Stockholm.
    Hu, Y.
    Chemical Engineering and Technology/Energy Processes, Royal Institute of Technology, Stockholm.
    Yan, Jinyue
    Mälardalens högskola, Akademin för hållbar samhälls- och teknikutveckling.
    Simulation and Optimization of Evaporative Gas Turbine with Chemical Absorption for Carbon Dioxide Capture2009Inngår i: International Journal of Green Energy, ISSN 1543-5075, E-ISSN 1543-5083, Vol. 6, nr 5, s. 527-539Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    This article studied the integration of an evaporative gas turbine (EvGT) cycle with chemical absorption for CO2 capture. Two systems of EvGT cycle without CO2 capture and EvGT cycle with CO2 capture were simulated and optimized. The impacts of key parameters such as the water/air ratio (W/A), the stripper pressure, and the flue-gas condensing temperature were studied regarding the electrical efficiency and CO2 reduction. Simulation results show that (1) there always exists an optimum point of W/A for both EvGT and EvGT combined with CCS; (2) although lowering the stripper pressure would lower the heat quality requirement of reboiler, it increases the quantity more obviously. Therefore increasing the operating pressure of stripper would help to increase the total electrical efficiency; but the efficiency improvement becomes smaller if stripper pressure is high; (3) adding a flue-gas condenser to condense out the excessive water is another method to increase the total electrical efficiency. There is also an optimum point of condensing temperature considering the concentration of mono ethanol amine (MEA) and inlet temperature of stripper; and (4) comparatively the combined cycle has a higher gross electricity generation and electrical efficiency than the EvGT cycle no matter if combined with CO2 capture or not.

  • 60.
    Li, Hailong
    et al.
    Mälardalens högskola, Akademin för hållbar samhälls- och teknikutveckling.
    Han, Song
    Mälardalens högskola, Akademin för hållbar samhälls- och teknikutveckling.
    Dahlquist, Erik
    Mälardalens högskola, Akademin för hållbar samhälls- och teknikutveckling.
    Thorin, Eva
    Mälardalens högskola, Akademin för hållbar samhälls- och teknikutveckling.
    Yan, Jinyue
    Mälardalens högskola, Akademin för hållbar samhälls- och teknikutveckling.
    Potentials of energy saving and efficiency improvement from lighting and space heating: a case study of SAAB2012Konferansepaper (Fagfellevurdert)
  • 61.
    Li, Hailong
    et al.
    Mälardalens högskola, Akademin för hållbar samhälls- och teknikutveckling.
    Hu, Yukun
    KTH, Sweden.
    Ditaranto, Mario
    SINTEF Energy Research, Trondheim, Norway .
    Willson, D
    Stanbridge Capital, New York, United States.
    Yan, Jinyue
    Mälardalens högskola, Akademin för hållbar samhälls- och teknikutveckling.
    Optimization of cryogenic CO2 purification for oxy-coal combustion2013Inngår i: Energy Procedia, ISSN 1876-6102, E-ISSN 1876-6102, Vol. 37, s. 1341-1347Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Oxyfuel combustion is a leading potential CO2 capture technology for power plants. As the flue gas (FG) consists of mainly H2O and CO2, a simpler and more energy-efficient CO2 purification method can be used instead of the standard amine-based chemical absorption approach. For the system of oxyfuel combustion with cryogenic CO2 purification, decreasing the oxygen purity reduces the energy consumption of the Air Separation Unit (ASU) but increases the energy consumption for the downstream cryogenic purification. Thus there exists a trade-off between the energy consumption of the ASU and that for cryogenic purification. This paper investigates the potential efficiency improvement by optimizing this trade-off. The simulated results show that there exists an optimum flue gas condensing pressure for the cryogenic purification, which is affected by the flue gas composition. In addition, decreasing the oxygen purity reduces the combined energy consumption of the ASU and the cryogenic purification, and therefore can improve the electrical efficiency. In summary, prior oxyfuel combustion analyses have assumed a high oxygen purity level of 95 mol% or 99 mol% for the combustion air, which achieves a high CO2 concentration in the flue gases. In this Paper, we demonstrate that a lower level of oxygen purity, such as 80 mol%, in conjunction with a more extensive cryogenic purification of the flue gases can lower the total energy consumption, thereby yielding a significant benefit. However, for oxygen purity levels lower than 75 mol%, it may not be possible to still use the two-stage flash system shown here to achieve a CO2 purity of 95 mol% and a CO2 recovery rate of 90% simultaneously.

  • 62.
    Li, Hailong
    et al.
    Mälardalens högskola, Akademin för hållbar samhälls- och teknikutveckling.
    Jakobsen, Jana P
    SINTEF Energy.
    Wilhelmsen, Øivind
    SINTEF Energy.
    Yan, Jinyue
    Mälardalens högskola, Akademin för hållbar samhälls- och teknikutveckling.
    PVTxy properties of CO2 mixtures relevant for CO2 capture, transport and storage: Review of available experimental data and theoretical models2011Inngår i: Applied Energy, ISSN 0306-2619, E-ISSN 1872-9118, Vol. 88, nr 11, s. 3567-3579Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The knowledge about pressure–volume–temperature–composition (PVTxy) properties plays an importantrole in the design and operation of many processes involved in CO2 capture and storage (CCS) systems.A literature survey was conducted on both the available experimental data and the theoreticalmodels associated with the thermodynamic properties of CO2 mixtures within the operation windowof CCS. Some gaps were identified between available experimental data and requirements of the systemdesign and operation. The major concerns are: for the vapour–liquid equilibrium, there are no data aboutCO2/COS and few data about the CO2/N2O4 mixture. For the volume property, there are no publishedexperimental data for CO2/O2, CO2/CO, CO2/N2O4, CO2/COS and CO2/NH3 and the liquid volume of CO2/H2. The experimental data available for multi-component CO2 mixtures are also scarce. Many equationsof state are available for thermodynamic calculations of CO2 mixtures. The cubic equations of state havethe simplest structure and are capable of giving reasonable results for the PVTxy properties. More complexequations of state such as Lee–Kesler, SAFT and GERG typically give better results for the volumeproperty, but not necessarily for the vapour–liquid equilibrium. None of the equations of state evaluatedin the literature show any clear advantage in CCS applications for the calculation of all PVTxy properties.A reference equation of state for CCS should, thus, be a future goal.

  • 63.
    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 biomethane2015Inngår i: Energy Conversion and Management, ISSN 0196-8904, E-ISSN 1879-2227, Vol. 100, s. 212-219Artikkel i tidsskrift (Fagfellevurdert)
    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.

  • 64.
    Li, Hailong
    et al.
    Mälardalens högskola, Akademin för hållbar samhälls- och teknikutveckling. Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Lindmark, Johan
    Mälardalens högskola, Akademin för hållbar samhälls- och teknikutveckling. Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Nordlander, Eva
    Mälardalens högskola, Akademin för hållbar samhälls- och teknikutveckling. Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Thorin, Eva
    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.
    Zhao, Li
    Tianjin University, China.
    Using the solid digestate from a wet anaerobic digestion process as an energy resource2013Inngår i: Energy technology, ISSN 2194-4296, Vol. 1, nr 1, s. 94-101Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The wet anaerobic digestion process is a widely used method to produce biogas from biomass. To avoid the risks involved with using the digestion waste as a fertilizer, this work investigates the possibilities to use the solid digestate as an energy resource to produce heat and electricity, which could save some energy currently consumed by the plant and, therefore, may increase the overall efficiency of a biogas plant. Simulations were conducted based on real data from the Växtkraft biogas plant in Västerås, Sweden as a case study. Results show that it is necessary to dry the solid digestate before combustion and include flue-gas condensation to recover enough heat for the drying process. When a steam turbine cycle is integrated, the generated electricity could cover 13–18 % of the total electricity consumption of the plant, depending on the degree of dryness. In addition, reducing the digestion period can increase the carbon content (ultimate analysis), the heating value, and the mass flow of the solid digestate. As a result, the production of electricity and heat is augmented in the steam turbine cycle. However, the production of biogas is reduced. Therefore, a comprehensive economic evaluation is suggested to optimize a biogas plant that uses the solid digestate from a wet anaerobic digestion process as an energy resource.

  • 65.
    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 heating2019Inngår i: Energy, Ecology and Environment, ISSN 2363-7692, Vol. 4, nr 1, s. 15-25Artikkel i tidsskrift (Fagfellevurdert)
    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.

  • 66.
    Li, Hailong
    et al.
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Sun, Qie
    Shandong University, China.
    Zhang, Qi
    China University of Petroleum, China.
    Wallin, Fredrik
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    A review of the pricing mechanisms for district heating systems2015Inngår i: Renewable & sustainable energy reviews, ISSN 1364-0321, E-ISSN 1879-0690, Vol. 42, s. 56-65Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Heating represents the largest proportion of energy use as supplied to consumers across all end energy uses. Therefore, there is huge potential for energy savings in the heating sector in order to reduce the emission of CO2. District heating (DH) has been considered an efficient, environmentally friendly and cost-effective method for heating in buildings, and is playing an important role in the mitigation of climate change. In the interest of fairness and in the highly competitive market the DH companies operate, there is a strong need to develop a novel heat pricing mechanism in order to promote sustainable development of DH systems. In this paper, existing methods and models regarding heat pricing have been reviewed. The features of different pricing mechanisms have been analysed, including advantages and disadvantages. Insights into developing an advanced pricing mechanism for DH systems have been offered.

  • 67.
    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 Plants2017Inngår i: Energy Procedia, Elsevier Ltd , 2017, s. 6030-6035Konferansepaper (Fagfellevurdert)
    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.

  • 68.
    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 CHP2019Inngår i: Energy, ISSN 0360-5442, E-ISSN 1873-6785, Vol. 180, s. 934-945Artikkel i tidsskrift (Fagfellevurdert)
    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. 

  • 69.
    Li, Hailong
    et al.
    Mälardalens högskola, Akademin för hållbar samhälls- och teknikutveckling.
    Wilhelmsen, Øivind
    SINTEF Energy Research.
    Lv, Yuexia
    Mälardalens högskola, Akademin för hållbar samhälls- och teknikutveckling.
    Wang, Weilong
    Mälardalens högskola, Akademin för hållbar samhälls- och teknikutveckling.
    Yan, Jinyue
    Mälardalens högskola, Akademin för hållbar samhälls- och teknikutveckling.
    Viscosities, thermal conductivities and diffusion coefficients of CO2 mixtures:Review of experimental data and theoretical models2011Inngår i: International Journal of Greenhouse Gas Control, ISSN 1750-5836, E-ISSN 1878-0148, Vol. 5, nr 5, s. 1119-1139Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Accurate experimental data on the thermo-physical properties of CO2-mixtures are pre-requisites fordevelopment of more accurate models and hence, more precise design of CO2 capture and storage (CCS)processes. A literature survey was conducted on both the available experimental data and the theoreticalmodels associated with the transport properties of CO2-mixtures within the operation windows ofCCS. Gaps were identified between the available knowledge and requirements of the system design andoperation. For the experimental gas-phase measurements, there are no available data about any transportproperties of CO2/H2S, CO2/COS and CO2/NH3; and except for CO2/H2O(/NaCl) and CO2/amine/H2Omixtures, there are no available measurements regarding the transport properties of any liquid-phasemixtures. In the prediction of gas-phase viscosities using Chapman–Enskog theory, deviations are typically<2% at atmospheric pressure and moderate temperatures. The deviations increase with increasingtemperatures and pressures. Using both the Rigorous Kinetic Theory (RKT) and empirical models in theprediction of gas-phase thermal conductivities, typical deviations are 2.2–9%. Comparison of popularempirical models for estimation of gas-phase diffusion coefficients with newer experimental data forCO2/H2O shows deviations of up to 20%. For many mixtures relevant for CCS, the diffusion coefficientmodels based on the RKT show predictions within the experimental uncertainty. Typical reported deviationsof the CO2/H2O system using empirical models are below 3% for the viscosity and the thermalconductivity and between 5 and 20% for the diffusion coefficients. The research community knows littleabout the effect of other impurities in liquid CO2 than water, and this is an important area to focus infuture work.

  • 70.
    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 Capture2015Inngår i: Handbook of Clean Energy Systems / [ed] Jinyue Yan, John Wiley & Sons, 2015, s. 1-17Kapittel i bok, del av antologi (Fagfellevurdert)
  • 71.
    LI, Hailong
    et al.
    Royal Institute of Technology.
    Yan, Jinyue
    Mälardalens högskola, Akademin för hållbar samhälls- och teknikutveckling. Energiteknik.
    Evaluating cubic equations of state for calculation of vapor-liquid equilibrium of CO(2) and CO(2)-mixtures for CO(2) capture and storage processes2009Inngår i: Applied Energy, ISSN 0306-2619, E-ISSN 1872-9118, Vol. 86, nr 6, s. 826-836Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Proper solution of vapor liquid equilibrium (VLE) is essential to the design and operation of CO2 capture and storage system (CCS). According to the requirements of engineering applications, cubic equations of state (EOS) are preferable to predict VLE properties. This paper evaluates the reliabilities of five cubic EOSs, including PR, PT, RK, SRK and 3P1T for predicting VLE of CO2 and binary CO2-mixtures containing CH4, H2S, SO2, Ar, N2 or O2, based on the comparisons with the collected experimental data. Results show that SRK is superior in the calculations about the saturated pressure of pure CO2; while for the VLE properties of binary CO2-mixtures, PR, PT and SRK are generally superior to RK and 3P1T. The impacts of binary interaction parameter kij were also analyzed. kij has very clear effects on the calculating accuracy of an EOS in the property calculations of CO2-mixtures. In order to improve the calculation accuracy, the binary interaction parameter was calibrated for all of the studied EOSs regarding every binary CO2-mixture.

  • 72.
    Li, Hailong
    et al.
    Chemical Engineering and Technology/Energy Processes, Royal Institute of Technology.
    Yan, Jinyue
    Mälardalens högskola, Akademin för hållbar samhälls- och teknikutveckling.
    Impacts of equations of state (EOS) and impurities on the volume calculation of CO2 mixtures in the applications of CO2 capture and storage (CCS) processes2009Inngår i: Applied Energy, ISSN 0306-2619, E-ISSN 1872-9118, Vol. 86, nr 12, s. 2760-2770Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Volume property is the necessary thermodynamic property in the design and operation of the CO2 capture and storage system (CCS). Because of their simple structures, cubic equations of state (EOS) are preferable to be applied in predicting volumes for engineering applications. This paper evaluates the reliabilities of seven cubic EOS, including PR, PT, RK, SRK, MPR, MSRK and ISRK for predicting volumes of binary CO2 mixtures containing CH4, H2S, SO2, Ar and N2, based on the comparisons with the collected experimental data. Results show that for calculations on the volume properties of binary CO2 mixtures, PR and PT are generally superior to others for all of the studied mixtures. In addition, it was found that the binary interaction parameter has clear effects on the calculating accuracy of an EOS in the volume calculations of CO2 mixtures. In order to improve the accuracy, kij was calibrated for all of the EOS regarding the gas and liquid phases of all the studied binary CO2 mixtures, respectively

  • 73.
    Li, Hailong
    et al.
    KTH.
    Yan, Jinyue
    Mälardalens högskola, Akademin för hållbar samhälls- och teknikutveckling.
    Performance Comparison on the Evaporative Gas Turbine Cycles Combined with Different CO2-Capture Options2009Inngår i: International Journal of Green Energy, ISSN 1543-5075, E-ISSN 1543-5083, Vol. 6, nr 5, s. 512-526Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    This article studied the integration of CO2 capture with evaporative gas turbine (EvGT) cycles. Two CO2 capture technologies are involved: MEA-based (monoethanolamine-based) chemical-absorption capture and O2/CO2 recycle combustion capture. Based on them, three system configurations were analyzed: (1) EvGT cycle without CO2 capture, (2) EvGT cycle with chemical-absorption capture, and (3) EvGT cycle with O2/CO2 recycle combustion capture. Simulation results show that the EvGT cycle with chemical-absorption capture has a higher electrical efficiency (39.73%) than the EvGT cycle with O2/CO2 recycle combustion capture (37.45%). Compared with the EvGT cycle without CO2 capture, the penalty on electrical efficiency caused by CO2 capture is 11.91% if EvGT is combined with chemical-absorption capture, and 14.19% if EvGT is combined with O2/CO2 recycle combustion capture. Moreover compared with combined cycles, EvGT cycles have a smaller gross electricity generation and a lower electrical efficiency no matter if they are combined with CO2 capture or not. Based on the analysis results of this article, several suggestions are also proposed to improve the net electrical efficiency of EvGT cycles with CO2 capture.

  • 74.
    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 capture2012Inngår i: International Journal of Greenhouse Gas Control, ISSN 1750-5836, E-ISSN 1878-0148, Vol. 9, s. 272-280Artikkel i tidsskrift (Fagfellevurdert)
    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.

  • 75.
    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 supply2013Inngår i: Applied Energy, ISSN 0306-2619, E-ISSN 1872-9118, Vol. 104, s. 178-186Artikkel i tidsskrift (Fagfellevurdert)
    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.

  • 76.
    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 study2015Inngår i: Energy Procedia, ISSN 1876-6102, E-ISSN 1876-6102, Vol. 75, s. 1838-1843Artikkel i tidsskrift (Fagfellevurdert)
    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.

  • 77.
    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 structures2019Inngår i: International journal of thermal sciences, ISSN 1290-0729, E-ISSN 1778-4166, Vol. 136, s. 86-95Artikkel i tidsskrift (Fagfellevurdert)
    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.

  • 78.
    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 warehouses2017Inngår i: Energy Procedia, ISSN 1876-6102, E-ISSN 1876-6102, Vol. 143, s. 94-99Artikkel i tidsskrift (Fagfellevurdert)
    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. 

  • 79.
    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 digestion2017Inngår i: Energy Procedia, ISSN 1876-6102, E-ISSN 1876-6102, Vol. 142, s. 938-942Artikkel i tidsskrift (Fagfellevurdert)
    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. 

  • 80.
    Li, Y.
    et al.
    Tsinghua University, Beijing, China.
    Jin, Y.
    Tsinghua University, Beijing, China.
    Borrion, A.
    University College London, London, United Kingdom.
    Li, Hailong
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Li, J.
    Tsinghua University, Beijing, China.
    Effects of organic composition on mesophilic anaerobic digestion of food waste2017Inngår i: Bioresource Technology, ISSN 0960-8524, E-ISSN 1873-2976, Vol. 244, s. 213-224Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Anaerobic digestion of food waste (FW) has been widely investigated, however, little is known about the influence of organic composition on the FW digestion process. This study aims to identify the optimum composition ratios of carbohydrate (CA), protein (CP) and lipid (EE) for maintaining high methane yield and process stability. The results show that the CA–CP–EE ratio was significantly correlated with performance and degradability parameters. Controlling the CA–CP–EE ratio higher than 1.89 (CA higher than 8.3%, CP lower than 5.0%, and EE lower than 5.6%) could be an effective way to maintain stable digestion and achieve higher methane production (385–627 mL/g VS) and shorter digestion retention (196–409 h). The CA-CP-EE ratio could be used as an important indicator for digestion performance. To effectively evaluate organic reduction, the concentration and removal efficiency of organic compositions in both solid phases and total FW should be considered. 

  • 81.
    Li, Y.
    et al.
    Tsinghua University, Beijing, China.
    Jin, Y.
    Tsinghua University, Beijing, China.
    Borrion, A.
    University College London, London, United Kingdom.
    Li, Hailong
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Li, J.
    Tsinghua University, Beijing, China.
    Effects of organic composition on the anaerobic biodegradability of food waste2017Inngår i: Bioresource Technology, ISSN 0960-8524, E-ISSN 1873-2976, Vol. 243, s. 836-845Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    This work investigated the influence of carbohydrates, proteins and lipids on the anaerobic digestion of food waste (FW) and the relationship between the parameters characterising digestion. Increasing the concentrations of proteins and lipids, and decreasing carbohydrate content in FW, led to high buffering capacity, reduction of proteins (52.7–65.0%) and lipids (57.4–88.2%), and methane production (385–627 mLCH4/g volatile solid), while achieving a short retention time. There were no significant correlations between the reduction of organics, hydrolysis rate constant (0.25–0.66 d−1) and composition of organics. Principal Component Analysis revealed that lipid, C, and N contents as well as the C/N ratio were the principal components for digestion. In addition, methane yield, the final concentrations of total ammonia nitrogen and free ammonia nitrogen, final pH values, and the reduction of proteins and lipids could be predicted by a second-order polynomial model, in terms of the protein and lipid weight fraction. 

  • 82.
    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 waste2018Inngår i: Applied Energy, ISSN 0306-2619, E-ISSN 1872-9118, Vol. 213, s. 136-147Artikkel i tidsskrift (Fagfellevurdert)
    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%.

  • 83.
    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 waste2016Inngår i: Applied Energy, ISSN 0306-2619, E-ISSN 1872-9118, Vol. 172, s. 47-58Artikkel i tidsskrift (Fagfellevurdert)
    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. 

  • 84.
    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 digestion2017Inngår i: Energy, ISSN 0360-5442, E-ISSN 1873-6785, Vol. 118, s. 377-386Artikkel i tidsskrift (Fagfellevurdert)
    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.

  • 85.
    Li, Y.
    et al.
    Academy of Chinese Energy Strategy, China University of Petroleum-Beijing, Changping, Beijing 102249, China.
    Li, Hailong
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Wang, G.
    Academy of Chinese Energy Strategy, China University of Petroleum-Beijing, Changping, Beijing 102249, China.
    Liu, X.
    Academy of Chinese Energy Strategy, China University of Petroleum-Beijing, Changping, Beijing 102249, China.
    Zhang, Q.
    Academy of Chinese Energy Strategy, China University of Petroleum-Beijing, Changping, Beijing 102249, China.
    Study on the optimal deployment for Photovoltaic components recycle in China2019Inngår i: Energy Procedia, Elsevier Ltd , 2019, Vol. 158, s. 4298-4303Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Photovoltaic (PV) production and installation surge in recent years because of technology development and policy orientation. However, due the deadlines of subsidy set by Chinese government, most of the PV projects are carried out in a hurry and quality issues appear. Some equipment turn out to be inferiors. The demand for subsequent treatment for PV components will surge in the early future. However, the insufficiency of recycle facilities and supporting policies, lack of public focus, make it difficult. For a better planning of PV recycle, an optimization model is applied to study on the optimal deployment of PV recycle centers in China during 2040 to 2045 based on cost minimization. Transportation cost for PV modules, capital cost and operational cost for recycle center in different provinces are taken into consideration of objective functions. The result indicates that the peak of PV components recycle will arrive around 2042. At the early stage, recycle centers will be established in Zhejiang, Guangdong, and Shanxi province, considering the intensive installation and convenient transportation. The discarded PV panels will be transported to those provinces. Then, as the recycle demand surging, recycle centers will be scattered in many provinces, such as Jiangsu, Ningxia, Hebei, Inner Mongolia and so on. Most of the PV components will be recycled within the installed provinces. 

  • 86.
    Li, Y.
    et al.
    Academy of Chinese Energy Strategy, China University of Petroleum-Beijing, Changping, Beijing 102249, China.
    Zhang, Q.
    Academy of Chinese Energy Strategy, China University of Petroleum-Beijing, Changping, Beijing 102249, China.
    Li, Hailong
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Tang, Y.
    Academy of Chinese Energy Strategy, China University of Petroleum-Beijing, Changping, Beijing 102249, China.
    Liu, B.
    Academy of Chinese Energy Strategy, China University of Petroleum-Beijing, Changping, Beijing 102249, China.
    The impact of dual-credit scheme on the development of the new energy vehicle industry2019Inngår i: Energy Procedia, Elsevier Ltd , 2019, Vol. 158, s. 4311-4317Konferansepaper (Fagfellevurdert)
    Abstract [en]

    In order to further promote the development of the new energy vehicle industry, Parallel Management regulation for corporate average fuel consumption and new energy vehicle credits for passenger vehicles (dual-credit scheme) have been proposed by Ministry of Industry and Information Technology in September 2017. This study attempted to investigate the impact of dual-credit scheme on the penetration of new energy vehicles and the short-term strategies of the automotive industry. For this purpose, a market analysis model is proposed based on game theory and the credit market equilibrium to quantify the effects of the credit trading mechanism. Four categories of automakers are considered. The obtained results show that: (i) The dual-credit scheme is indeed an effective policy solution that enables the expansion of the volume of NEV market. (ii) The dual-credit scheme can accelerate the elimination of outdated technologies with lower driving mileage, and it can also promote the adoption of technologies with longer driving mileage. (iii) The dual-credit scheme allows all automakers to achieve their targets in a market efficient manner. 

  • 87.
    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 China2019Inngår i: Bioresource Technology, ISSN 0960-8524, E-ISSN 1873-2976, Vol. 273, s. 654-665Artikkel i tidsskrift (Fagfellevurdert)
  • 88.
    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 hållbar samhälls- och teknikutveckling. Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Yu, Zhixin
    Universitetet i Stavanger.
    Effects of pungency degree on mesophilic anaerobic digestion of kitchen waste2016Inngår i: Applied Energy, ISSN 0306-2619, E-ISSN 1872-9118, Vol. 181, s. 171-178Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    This study investigated the influence of pungency degrees (PDs) on mesophilic anaerobic digestion of kitchen waste (KW). Batch tests were performed to evaluate the methane potential and production rate and the effect of PDs on organics degradation efficiency (in terms of volatile solids, protein and ether extract) at mesophilic temperature. Koch and Drewes model and modified Gompertz model were applied to assess the effects of PDs on the hydrolysis rate constant, biomethane yield rate and lag time. The results revealed that with the increasing contributions of PDs, the methane yield, organics degradation efficiency and hydrolysis rate of KW decreased while the pH values and concentrations of total ammonia nitrogen and free ammonia nitrogen were increased. Additionally, PDs lower than PD3 presented better digestion performance, and according to results of organics degradation and kinetics study, it could be suggested that appropriate range of PD in KW beneficial for AD is PD5-PD4.

  • 89.
    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 Piles2016Inngår i: CLEAN ENERGY FOR CLEAN CITY: CUE 2016 - APPLIED ENERGY SYMPOSIUM AND FORUM: LOW-CARBON CITIES AND URBAN ENERGY SYSTEMS, 2016, s. 336-341Konferansepaper (Fagfellevurdert)
    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.

  • 90. 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 analysis2017Inngår i: Applied Energy, ISSN 0306-2619, E-ISSN 1872-9118, Vol. 196, s. 238-248Artikkel i tidsskrift (Fagfellevurdert)
  • 91.
    Lin, H.
    et al.
    Institute of Thermal Science and Technology, Shandong University, Jinan, China.
    Fu, K.
    Institute of Thermal Science and Technology, Shandong University, Jinan, China.
    Wang, Y.
    Institute of Thermal Science and Technology, Shandong University, Jinan, China.
    Sun, Q.
    Institute of Thermal Science and Technology, Shandong University, Jinan, China.
    Li, Hailong
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Hu, Y.
    Sun, B.
    Department of Civil, Environmental & Geomatic Engineering, University College London, London, United Kingdom.
    Wennersten, R.
    Institute of Thermal Science and Technology, Shandong University, Jinan, China.
    Characteristics of electric vehicle charging demand at multiple types of location - Application of an agent-based trip chain model2019Inngår i: Energy, ISSN 0360-5442, E-ISSN 1873-6785, Vol. 188, artikkel-id 116122Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    This paper developed an agent-based trip chain model (ABTCM) to study the distribution of electric vehicles (EVs) charging demand and its dynamic characteristics, including flexibility and uncertainty, at different types of location. Key parameters affecting charging demand include charging strategies, i.e. uncontrolled charging (UC) and off-peak charging (OPC), and EV supply equipment, including three levels of charging equipment. The results indicate that the distributions of charging demand are similar as the travel patterns, featured by traffic flow at each location. A discrete peak effect was found in revealing the relation between traffic flow and charging demand, and it results in the smallest equivalent daily charging demand and peak load at public locations. EV charging and vehicle-to-grid (V2G) flexibility were examined by instantaneous adjustable power and accumulative adjustable amount of electricity. The EVs at home locations have the largest charging and V2G flexibility under the UC strategy, except for a period of regular working time. The V2G flexibility at work and public locations is generally larger than charging flexibility. Due to the fast charging application, the uncertainties of charging demand at public locations are the highest in all locations. In addition, the OPC strategy mitigates the uncertainty of charging demand. 

  • 92.
    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 simulation2018Inngår i: Applied Energy, ISSN 0306-2619, E-ISSN 1872-9118, Vol. 230, s. 189-206Artikkel i tidsskrift (Fagfellevurdert)
    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.

  • 93.
    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 Area2018Inngår i: JOINT INTERNATIONAL CONFERENCE ON ENERGY, ECOLOGY AND ENVIRONMENT ICEEE 2018 AND ELECTRIC AND INTELLIGENT VEHICLES ICEIV 2018, DESTECH PUBLICATIONS, INC , 2018Konferansepaper (Fagfellevurdert)
    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.

  • 94.
    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 Method2017Inngår i: Energy Procedia, ISSN 1876-6102, E-ISSN 1876-6102, Vol. 142, s. 780-786Artikkel i tidsskrift (Fagfellevurdert)
    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.

  • 95.
    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 System2019Inngår i: Energy Conversion and Management, ISSN 0196-8904, E-ISSN 1879-2227, Vol. 194, s. 173-185Artikkel i tidsskrift (Fagfellevurdert)
    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.

  • 96.
    Liu, S.
    et al.
    Tianjin Key Laboratory of Refrigeration Technology, Tianjin University of Commerce, China.
    Lu, F.
    Tianjin Key Laboratory of Refrigeration Technology, Tianjin University of Commerce, China.
    Dai, B.
    Tianjin Key Laboratory of Refrigeration Technology, Tianjin University of Commerce, China.
    Nian, V.
    Energy Studies Institute, National University of Singapore, Singapore.
    Li, Hailong
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Qi, H.
    Tianjin Key Laboratory of Refrigeration Technology, Tianjin University of Commerce, China.
    Li, J.
    Tianjin Key Laboratory of Refrigeration Technology, Tianjin University of Commerce, China.
    Performance analysis of two-stage compression transcritical CO2 refrigeration system with R290 mechanical subcooling unit2019Inngår i: Energy, ISSN 0360-5442, E-ISSN 1873-6785, Vol. 189, artikkel-id 116143Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The use of carbon dioxide (CO2) as refrigerant is driven by the need to phase down the traditional synthetic refrigerant so as to mitigate the warming climate. In this study, the thermal performance of a two-stage compression transcritical CO2 refrigeration system with R290 mechanical subcooling unit is conducted. The goal is to obtain the maximum coefficient of performance (COP) of five different mechanical subcooling systems under the optimal subcooling temperature and compressor discharge pressure. The two-throttling and two-stage compression high-pressure mechanical subcooling system is found to have a higher COP. When the evaporation temperature is −30 °C, the COP of the two-throttling and two-stage compression high-pressure mechanical subcooling system is improved by 76.74%. The COP of the two-throttling and two-stage compression high-pressure mechanical subcooling system is 1.52 at an ambient temperature of 40 °C, which is 21.87% higher than that of the two-throttling and two-stage compression low-pressure mechanical subcooling system. The power consumption ratio of one-throttling and two-stage compression low-pressure mechanical subcooling system is significantly higher than that of other systems. From a comprehensive analysis of the proposed four systems, the two-throttling and two-stage compression high-pressure mechanical subcooling system has the best performance over all other systems. 

  • 97.
    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 expanders2017Inngår i: HKIE Transactions Hong Kong Institution of Engineers, ISSN 1023-697X, Vol. 24, nr 2, s. 70-77Artikkel i tidsskrift (Fagfellevurdert)
    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. 

  • 98.
    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 China2019Inngår i: Applied Thermal Engineering, ISSN 1359-4311, E-ISSN 1873-5606, Vol. 148, s. 1425-1439Artikkel i tidsskrift (Fagfellevurdert)
    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.

  • 99.
    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 technologies2019Inngår i: Energy Conversion and Management, ISSN 0196-8904, E-ISSN 1879-2227, Vol. feb, s. 608-620Artikkel i tidsskrift (Fagfellevurdert)
    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.

  • 100.
    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 pump2012Inngår i: Applied Energy, ISSN 0306-2619, E-ISSN 1872-9118, Vol. 97, nr SI, s. 869-875Artikkel i tidsskrift (Fagfellevurdert)
    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.

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