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  • 151.
    Gustafsson, M.
    et al.
    KTH Royal Institute of Technology, Stockholm, Sweden.
    Swing Gustafsson, Moa
    Mälardalen University, School of Business, Society and Engineering, Future Energy Center.
    Myhren, J. A.
    Dalarna University, Falun, Sweden.
    Bales, C.
    Dalarna University, Falun, Sweden.
    Holmberg, S.
    KTH Royal Institute of Technology, Stockholm, Sweden.
    Techno-economic analysis of energy renovation measures for a district heated multi-family house2016In: Applied Energy, ISSN 0306-2619, E-ISSN 1872-9118, Vol. 177, p. 108-116Article in journal (Refereed)
    Abstract [en]

    Renovation of existing buildings is important in the work toward increased energy efficiency and reduced environmental impact. The present paper treats energy renovation measures for a Swedish district heated multi-family house, evaluated through dynamic simulation. Insulation of roof and façade, better insulating windows and flow-reducing water taps, in combination with different HVAC systems for recovery of heat from exhaust air, were assessed in terms of life cycle cost, discounted payback period, primary energy consumption, CO2 emissions and non-renewable energy consumption. The HVAC systems were based on the existing district heating substation and included mechanical ventilation with heat recovery and different configurations of exhaust air heat pump.Compared to a renovation without energy saving measures, the combination of new windows, insulation, flow-reducing taps and an exhaust air a heat pump gave up to 24% lower life cycle cost. Adding insulation on roof and façade, the primary energy consumption was reduced by up to 58%, CO2 emissions up to 65% and non-renewable energy consumption up to 56%. Ventilation with heat recovery also reduced the environmental impact but was not economically profitable in the studied cases. With a margin perspective on electricity consumption, the environmental impact of installing heat pumps or air heat recovery in district heated houses is increased. Low-temperature heating improved the seasonal performance factor of the heat pump by up to 11% and reduced the environmental impact. 

  • 152.
    Gustafsson, Marcus
    et al.
    Dalarna University, School of Technology and Business Studies, Energy Technology.
    Swing Gustafsson, Moa
    Dalarna University, School of Technology and Business Studies, Energy Technology.
    Myhren, Jonn Are
    Dalarna University, School of Technology and Business Studies, Construction.
    Bales, Chris
    Dalarna University, School of Technology and Business Studies, Energy Technology.
    Holmberg, Sture
    Techno-economic analysis of energy renovation measures for a district heated multi-family house2016In: Applied Energy, ISSN 0306-2619, E-ISSN 1872-9118, Vol. 177, p. 108-116Article in journal (Refereed)
    Abstract [en]

    Renovation of existing buildings is important in the work toward increased energy efficiency and reduced environmental impact. The present paper treats energy renovation measures for a Swedish district heated multi-family house, evaluated through dynamic simulation. Insulation of roof and façade, better insulating windows and flow-reducing water taps, in combination with different HVAC systems for recovery of heat from exhaust air, were assessed in terms of life cycle cost, discounted payback period, primary energy consumption, CO2 emissions and non-renewable energy consumption. The HVAC systems were based on the existing district heating substation and included mechanical ventilation with heat recovery and different configurations of exhaust air heat pump.Compared to a renovation without energy saving measures, the combination of new windows, insulation, flow-reducing taps and an exhaust air a heat pump gave up to 24% lower life cycle cost. Adding insulation on roof and façade, the primary energy consumption was reduced by up to 58%, CO2 emissions up to 65% and non-renewable energy consumption up to 56%. Ventilation with heat recovery also reduced the environmental impact but was not economically profitable in the studied cases. With a margin perspective on electricity consumption, the environmental impact of installing heat pumps or air heat recovery in district heated houses is increased. Low-temperature heating improved the seasonal performance factor of the heat pump by up to 11% and reduced the environmental impact.

  • 153.
    Gustafsson, Marcus
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Fluid and Climate Technology. Dalarna University, Sweden.
    Swing Gustafsson, Moa
    Högskolan Dalarna, Energiteknik; Mälardalens Högskola.
    Myhren, Jonn Are
    Högskolan Dalarna, Byggteknik.
    Bales, Chris
    Högskolan Dalarna, Energiteknik.
    Holmberg, Sture
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Fluid and Climate Technology.
    Techno-economic analysis of energy renovation measures for a district heated multi-family house2016In: Applied Energy, ISSN 0306-2619, E-ISSN 1872-9118, Vol. 177, p. 108-116Article in journal (Refereed)
    Abstract [en]

    Renovation of existing buildings is important in the work towards increased energy efficiency and reduced environmental impact. The present paper treats energy renovation measures for a Swedish district heated multi-family house, evaluated through dynamic simulation. Insulation of roof and façade, better insulating windows and flow-reducing water taps, in combination with different HVAC systems for recovery of heat from exhaust air, were assessed in terms of life cycle cost, discounted payback period, primary energy consumption, CO₂ emissions and non-renewable energy consumption. The HVAC systems were based on the existing district heating substation and included mechanical ventilation with heat recovery and different configurations of exhaust air heat pump.

    Compared to a renovation without energy saving measures, the combination of new windows, insulation, flow-reducing taps and an exhaust air a heat pump gave up to 24% lower life cycle cost. Adding insulation on roof and façade, the primary energy consumption was reduced by up to 58%, CO₂ emissions up to 65% and non-renewable energy consumption up to 56%. Ventilation with heat recovery also reduced the environmental impact but was not economically profitable in the studied cases. With a margin perspective on electricity consumption, the environmental impact of installing heat pumps or air heat recovery in district heated houses is increased. Low-temperature heating improved the seasonal performance factor of the heat pump by up to 11% and reduced the environmental impact.

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  • 154.
    Gustafsson, Stig-Inge
    Linköping University, Department of Management and Engineering, Energy Systems. Linköping University, The Institute of Technology.
    Climate Influence on District Heat and Electricity Demands1992In: Applied Energy, ISSN 0306-2619, E-ISSN 1872-9118, Vol. 42, no 4, p. 313-320Article in journal (Refereed)
    Abstract [en]

    This paper describes the district heating and electricity load of Kalmar, Sweden. Unfortunately, it has not been possible to examine one full year because the monitoring of the energy use for district heating and electricity, and the outdoor temperature, did not exactly overlap. However, more than 7200 h, of the 8760 in a full year, have been examined. It is shown that the district heat load has a far higher correlation with the outdoor temperature (a coefficient of 0·89), than has the electricity load (0·33). Thus, it is much easier to predict the influence of, e.g. an insulation retrofit for the building stock where district heating is used compared with electricity space heating. It is also shown how an estimate can be made of the thermal transmission factor for the total building stock.

  • 155.
    Gustafsson, Stig-Inge
    Linköping University, Department of Management and Engineering, Energy Systems. Linköping University, The Institute of Technology.
    Mathematical modelling of district-heating and electricity loads1993In: Applied Energy, ISSN 0306-2619, E-ISSN 1872-9118, Vol. 46, no 2, p. 149-159Article in journal (Refereed)
    Abstract [en]

    In recent years it has been more common to use linear or mixed-integer programming methods for finding optimal solutions to the complicated operating options in modern Combined Heat and Power (CHP) networks. Electricity may be bought from the national grid or it may be produced in ordinary condenser or CHP plants owned by the utility. In the same manner, district heat can be produced by the use of waste heat from industries or from a CHP plant. Other options are burning garbage in an incineration plant, using heat pumps in a sewage water plant or just burning fuels in an ordinary boiler. Combining these options and including the possibility of using conservation measures in industry or in the housing stock will result in a very complex situation if one tries to find the optimal solution characterized by the the lowest Life-Cycle Cost (LCC). Load management equipment, such as hot-water accumulators, will aggravate the problem even further. By the use of modern computers, complicated problems can be solved within a reasonable period of time. The bases for the mathematical models are the thermal and electrical loads. Splitting these loads into finer and finer segments will yield a model that will depict reality more closely. Two methods have been used frequently, one where the high and low unit price hours in each month have been lumped together, resulting in 24 segments plus one segment showing the influence of the maximum electricity demand. The other method tries to model the loads by lumping the energy demand in six electricity-tariff segments, but also using about 15 elements for a more versatile picture of the district-heating load. This paper describes the two methods using monitored data for 1990-1991 from Kalmar in the south of Sweden. It also discusses which of the methods is preferable or whether a combination must be elaborated upon in order to model reality closely enough for practical use.

  • 156.
    Gustafsson, Stig-Inge
    Linköping University, Department of Mechanical Engineering, Energy Systems. Linköping University, The Institute of Technology.
    Sensitivity analysis of building energy retrofits1998In: Applied Energy, ISSN 0306-2619, E-ISSN 1872-9118, Vol. 61, no 1, p. 13-23Article in journal (Refereed)
    Abstract [en]

    When a building is refurbished, energy conservation measures might be profitable to implement. The profitability depends, among other things, on the electricity and district-heating tariffs, the unit price for oil, etc. The cost for the retrofit is of course also important as well as the influence of the retrofit on the demand for heat in the building. By the use of a Mixed Integer Linear Programming model of a building, a number of different optimal retrofit strategies are found depending on the energy cost. The result shows that the Life-Cycle Cost for the building is subject only to small changes as long as the optimal strategies are chosen. Most important is the heating system, while building retrofits such as added insulation, are too expensive to take part in the optimal solution.

  • 157.
    Gustafsson, Stig-Inge
    et al.
    Linköping University, Department of Management and Engineering, Energy Systems. Linköping University, The Institute of Technology.
    Karlsson, Björn G
    Linköping University, Department of Management and Engineering, Energy Systems. Linköping University, The Institute of Technology.
    Insulation and Bivalent Heating System Optimization: Residential Housing Retrofits and Time-Of-Use Tariffs for Electricity1989In: Applied Energy, ISSN 0306-2619, E-ISSN 1872-9118, Vol. 34, no 4, p. 303-315Article in journal (Refereed)
    Abstract [en]

    Time-of-use tariffs, which reflect the cost of producing one extra unit of electricity, will be more common in the future. In Sweden the electricity unit price will be high during the winter and cheaper during the summer. A bivalent heating system, where an oil-fired boiler takes care of the peak load, when the electricity price is high, and a heat pump the base load, may decrease the cost of space heating substantially. However, insulation retrofits are also likely to reduce the peak space-heating load in a building. This paper shows how a bivalent heating system can be optimized while also considering the insulation measures. The optimization is elaborated by the use of a mixed integer programming model and the result is compared with a derivative optimization method used in the OPERA (optimal energy retrofit advisory) model. Both models use the life-cycle cost (LCC) as a ranking criterion, i.e. when the lowest LCC for the building is achieved, no better retrofit combination exists for the remaining life of the building.

  • 158.
    Gustafsson, Stig-Inge
    et al.
    Linköping University, Department of Management and Engineering, Energy Systems. Linköping University, The Institute of Technology.
    Karlsson, Björn G
    Linköping University, Department of Management and Engineering, Energy Systems. Linköping University, The Institute of Technology.
    Is space heating in offices really necessary?1991In: Applied Energy, ISSN 0306-2619, E-ISSN 1872-9118, Vol. 38, no 4, p. 283-291Article in journal (Refereed)
    Abstract [en]

    New office buildings in Sweden are thoroughly insulated due to the Swedish building code. This code, however, does not consider the type of activity occurring in the building. This means that the heating equipment is designed as if no activity at all is going on. In modern offices there is a lot of equipment installed which uses electricity. This electricity is converted into heat which can be utilized for heating the premises, mostly in a direct way but also by the use of exhaust-air heat-pumps or heat exchangers. This paper deals with a modern office building plus office hotel complex located in Linköping, Sweden, about 200 km south of Stockholm. The tenants deal with the design of hard- and software for computers. The lighting and computers in the building use electricity which converts into heat. In this paper, it is shown that this electricity is all that is needed during normal conditions, i.e. when people work in the building. The building is also equipped with a district-heating system, which is designed as if no activity goes on in the building, so subsequently the heating equipment is larger than it need be. In this special case, it might have been better to install an electric heating device for hot-water heating and very cold winter conditions, instead of using district heating. This is so even if district heat is about half the unit price compared with that due to the dissipation of electricity. At present, when district heating is used, no measures for saving heat can be profitable due to the low district-heating price. The fact is that the tenants complain of too much heat instead of too little: the prevailing indoor temperature was about 24° C in January 1990 even though 20° C would have been sufficient. There is subsequently a need for a properly working regulation system. The one currently in use is designed to a modern standard, but is not able to maintain temperatures at a modest level.

  • 159.
    Gustafsson, Stig-Inge
    et al.
    Linköping University, Department of Management and Engineering, Energy Systems. Linköping University, The Institute of Technology.
    Karlsson, Björn G
    Linköping University, Department of Management and Engineering, Energy Systems. Linköping University, The Institute of Technology.
    Window Retrofits: Interaction and Life-Cycle Costing1991In: Applied Energy, ISSN 0306-2619, E-ISSN 1872-9118, Vol. 39, no 1, p. 21-29Article in journal (Refereed)
    Abstract [en]

    This paper deals with the interaction between different types of building energy retrofits. The means for finding this interaction has been via the OPERA model, which is used for energy retrofit optimization. The solution is an optimum when the total life-cycle cost, LCC, for the building, i.e. the sum of the building, maintenance and operating costs, is minimized. The model finds the candidates for the optimal strategy by calculating the total LCC for one retrofit after another, i.e., an incremental method is used. All the measures are implemented with respect to the building and the resulting LCC is calculated. Usually, the LCC for this combination is higher than the incremental LCC, i.e. the incremental way of calculation overestimates the savings. However, when window retrofits are considered, the opposite might happen due to the use of shading factors. These factors indicate the decrease in solar radiation through a window when an ordinary one is replaced by a window with enhanced thermal performance. The paper also shows that the interaction between the different measures usually can be neglected, as long as optimal retrofits are introduced.

  • 160.
    Gustafsson, Stig-Inge
    et al.
    Linköping University, Department of Management and Engineering.
    Probert, S. D.
    Electricity use in the Swedish carpentry industry1995In: Applied Energy, ISSN 0306-2619, E-ISSN 1872-9118, Vol. 52, no 1, p. 73-85Article in journal (Refereed)
  • 161.
    Gustavsson, Jenny
    et al.
    Linköping University, The Tema Institute. Linköping University, Faculty of Arts and Sciences. Linköping University, Biogas Research Center.
    Shakeri Yekta, Sepehr
    Linköping University, The Tema Institute, Department of Water and Environmental Studies. Linköping University, Faculty of Arts and Sciences. Linköping University, Biogas Research Center.
    Sundberg, Carina
    Linköping University, The Tema Institute, Department of Water and Environmental Studies. Linköping University, Faculty of Arts and Sciences. Linköping University, Biogas Research Center.
    Karlsson, Anna
    Linköping University, Biogas Research Center. Scandinavian Biogas Fuels AB, Sweden .
    Ejlertsson, Jörgen
    Linköping University, The Tema Institute, Department of Water and Environmental Studies. Linköping University, Faculty of Arts and Sciences. Linköping University, Biogas Research Center.
    Skyllberg, Ulf
    Linköping University, Biogas Research Center. Swedish University of Agriculture Science, Sweden .
    Svensson, Bo
    Linköping University, The Tema Institute, Department of Water and Environmental Studies. Linköping University, Faculty of Arts and Sciences. Linköping University, Biogas Research Center.
    Bioavailability of cobalt and nickel during anaerobic digestion of sulfur-rich stillage for biogas formation2013In: Applied Energy, ISSN 0306-2619, E-ISSN 1872-9118, Vol. 112, p. 473-477Article in journal (Refereed)
    Abstract [en]

    Addition of Co and Ni often improves the production of biogas during digestion of organic matter, i.e. increasing CH4-production, process stability and substrate utilization which often opens for higher organic loading rates (OLRs). The effect of Co and Ni addition was evaluated by measuring methane production, volatile solids reduction, pH and concentration of volatile fatty acids (VFAs). A series of six lab-scale semi-continuously fed biogas tank reactors were used for this purpose. The chemical forms and potential bioavailability of Co and Ni were examined by sequential extraction, acid volatile sulfide extraction (AVS) and simultaneously extracted metals. Furthermore, the sulfur speciation in solid phase was examined by sulfur X-ray absorption near edge structure spectroscopy. The effect of Co and Ni deficiency on the microbial community composition was analyzed using quantitative polymerase chain reaction and 454-pyrosequencing. The results showed that amendment with Co and Ni was necessary to maintain biogas process stability and resulted in increased CH4-production and substrate utilization efficiency. 10-20% of the total Co concentration was in dissolved form and should be regarded as easily accessible by the microorganisms. In contrast, Ni was entirely associated with organic matter/sulfides (mainly AVS) and regarded as very difficult to take up. Still Ni had stimulatory effects suggesting mechanisms such as dissolution of NiS to be involved in the regulation of Ni availability for the microorganisms. The microbial community structure varied in relation to the occurrence of Ni and Co. The acetate-utilizing Methanosarcinales dominated during stable process performance, i.e. when both Co and Ni were supplied, while hydrogenotrophic Methanomicrobiales increased together with VFA concentrations under Co or Ni deficiency. The increase was more pronounced at Co limitation. This study demonstrates that there are good possibilities to improve the performance of biogas processes digesting sulfur-rich substrates by supplementation of Co and Ni.

  • 162.
    Gustavsson, Leif
    et al.
    Mittuniversitetet, Institutionen för teknik och hållbar utveckling.
    Eriksson, Lisa
    Mittuniversitetet, Institutionen för teknik och hållbar utveckling.
    Sathre, Roger
    Mittuniversitetet, Institutionen för teknik och hållbar utveckling.
    Costs and CO2 benefits of recovering, refining and transporting logging residues for fossil fuel replacement2011In: Applied Energy, ISSN 0306-2619, E-ISSN 1872-9118, Vol. 88, no 1, p. 192-197Article in journal (Refereed)
    Abstract [en]

    There are many possible systems for recovering, refining, and transporting logging residues for use as fuel. Here we analyse costs, primary energy and CO2 benefits of various systems for using logging residues locally, nationally or internationally. The recovery systems we consider are a bundle system and a traditional chip system in a Nordic context. We also consider various transport modes and distances, refining the residues into pellets, and replacing different fossil fuels. Compressing of bundles entails costs, but the cost of chipping is greatly reduced if chipping is done on a large scale, providing an overall cost-effective system. The bundle system entails greater primary energy use, but its lower dry-matter losses mean that more biomass per hectare can be extracted from the harvest site. Thus, the potential replacement of fossil fuels per hectare of harvest area is greater with the bundle system than with the chip system. The fuel-cycle reduction of CO2 emissions per harvest area when logging residues replace fossil fuels depends more on the type of fossil fuel replaced, the logging residues recovery system used and the refining of the residues, than on whether the residues are transported to local, national or international end-users. The mode and distance of the transport system has a minor impact on the CO2 emission balance.

  • 163.
    Gustavsson, Leif
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Engineering and Sustainable Development.
    Eriksson, Lisa
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Engineering and Sustainable Development.
    Sathre, Roger
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Engineering and Sustainable Development.
    Costs and CO2 benefits of recovering, refining and transporting logging residues for fossil fuel replacement2011In: Applied Energy, ISSN 0306-2619, E-ISSN 1872-9118, Vol. 88, no 1, p. 192-197Article in journal (Refereed)
    Abstract [en]

    There are many possible systems for recovering, refining, and transporting logging residues for use as fuel. Here we analyse costs, primary energy and CO2 benefits of various systems for using logging residues locally, nationally or internationally. The recovery systems we consider are a bundle system and a traditional chip system in a Nordic context. We also consider various transport modes and distances, refining the residues into pellets, and replacing different fossil fuels. Compressing of bundles entails costs, but the cost of chipping is greatly reduced if chipping is done on a large scale, providing an overall cost-effective system. The bundle system entails greater primary energy use, but its lower dry-matter losses mean that more biomass per hectare can be extracted from the harvest site. Thus, the potential replacement of fossil fuels per hectare of harvest area is greater with the bundle system than with the chip system. The fuel-cycle reduction of CO2 emissions per harvest area when logging residues replace fossil fuels depends more on the type of fossil fuel replaced, the logging residues recovery system used and the refining of the residues, than on whether the residues are transported to local, national or international end-users. The mode and distance of the transport system has a minor impact on the CO2 emission balance.

  • 164.
    Gustavsson, Leif
    et al.
    Linnaeus University, Faculty of Technology, Department of Built Environment and Energy Technology.
    Haus, Sylvia
    Linnaeus University, Faculty of Technology, Department of Built Environment and Energy Technology.
    Ortiz, Carina A.
    Swedish University of Agricultural Sciences.
    Sathre, Roger
    Linnaeus University, Faculty of Technology, Department of Built Environment and Energy Technology.
    Truong, Nguyen Le
    Linnaeus University, Faculty of Technology, Department of Built Environment and Energy Technology.
    Climate effects of bioenergy from forest residues in comparison to fossil energy2015In: Applied Energy, ISSN 0306-2619, E-ISSN 1872-9118, Vol. 138, p. 36-50Article in journal (Refereed)
    Abstract [en]

    Forest residues can be left at the harvest site to gradually decompose, or can be collected for energy purposes. This study analyzes the primary energy and climate impacts of bioenergy systems where forest residues are collected and used for electricity, heat and transportation, compared to fossil-based energy systems where fossil fuels provide the same services while forest residues are left on site to decompose. Time profiles are elaborated of primary energy use and carbon dioxide emissions from various energy applications fulfilled by bioenergy or fossil energy systems. Different biological decay functions are considered based on process-based modeling and inventory data across various climate zones. For all scenarios, the changes in cumulative radiative forcing (CRF) are calculated over a 300-year period, to evaluate the short- and long-term contributions of forest residue to climate change mitigation. A life cycle perspective along the full energy chains is used to evaluate the overall effectiveness of each system. The results show largest primary energy and climate benefits when forest residues are collected and used efficiently for energy services. Using biomass to substitute fossil coal provides greater climate change mitigation benefits than substituting oil or fossil gas. Some bioenergy substitutions result in positive CRF, i.e. increased global warming, during an initial period. This occurs for relatively inefficient bioenergy conversion pathways to substitute less carbon intensive fossil fuels, e.g. biomotor fuel used to replace diesel. More beneficial bioenergy substitutions, such as efficiently replacing coal, result immediately in reduced CRF. Biomass decay rates and transportation distance have less influence on climate benefits.

  • 165.
    Görling, Martin
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Energy Processes.
    Larsson, Mårten
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Energy Processes.
    Alvfors, Per
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Energy Processes.
    Bio-methane via fast pyrolysis of biomass2013In: Applied Energy, ISSN 0306-2619, E-ISSN 1872-9118, Vol. 112, no SI, p. 440-447Article in journal (Refereed)
    Abstract [en]

    Bio-methane, a renewable vehicle fuel, is today produced by anaerobic digestion and a 2nd generation production route via gasification is under development. This paper proposes a poly-generation plant that produces bio-methane, bio-char and heat via fast pyrolysis of biomass. The energy and material flows for the fuel synthesis are calculated by process simulation in Aspen Plus®. The production of bio-methane and bio-char amounts to 15.5. MW and 3.7. MW, when the total inputs are 23. MW raw biomass and 1.39. MW electricity respectively (HHV basis). The results indicate an overall efficiency of 84% including high-temperature heat and the biomass to bio-methane yield amounts to 83% after allocation of the biomass input to the final products (HHV basis). The overall energy efficiency is higher for the suggested plant than for the gasification production route and is therefore a competitive route for bio-methane production.

  • 166.
    Hagos, Dejene Assefa
    et al.
    Linnaeus University, Faculty of Technology, Department of Built Environment and Energy Technology. Gjovik Univ Coll.
    Gebremedhin, Alemayehu
    Gjovik Univ Coll.
    Zethraeus, Björn
    Linnaeus University, Faculty of Technology, Department of Built Environment and Energy Technology.
    Towards a flexible energy system - A case study for Inland Norway2014In: Applied Energy, ISSN 0306-2619, E-ISSN 1872-9118, Vol. 130, p. 41-50Article in journal (Refereed)
    Abstract [en]

    This paper analyze the benefits of the use of bioenergy, solar thermal and wind energy in a flexible energy system to increase the share of renewable sources (RES) in primary energy supply, reduce primary energy consumption (PEC) and ensure power supply security in Inland Norway, and Norway at large. Firstly, the Inland reference energy system was built and validated using the EnergyPLAN system analysis tool based on the year 2009. Two alternative systems (scenarios), mainly of bio-heat and heat pumps in individual and district heating systems were then constructed and compared with the reference system using EnergyPLAN. The quality of a given energy system can be best described by its PEC, RES, emission levels and socio-economic costs. The result shows that it is plausible to improve the quality of the Inland energy system by optimal resource assortment in the energy mix. Integrated use of bin-heat and heat pumps in individual and district heating systems, as a replacement for direct electric heaters would reduce PEC and socio-economic costs considerably more than intensive bio-heating deployment alone, thereby increasing total domestic green electricity generation. The ability to integrate wind power and its value in the Inland energy system is more reflected by reducing imports of electricity during peak demand periods in winter, as wind power availability in the region is significant as opposed to the low precipitation during these periods. In addition, increasing wind energy penetration helps to limit biomass consumption in a district heating system built on heat pumps and bio-heat boilers. (C) 2014 Elsevier Ltd. All rights reserved.

  • 167.
    Han, Song
    et al.
    Mälardalen University, School of Sustainable Development of Society and Technology.
    Starfelt, Fredrik
    Mälardalen University, School of Sustainable Development of Society and Technology.
    Daianova, Lilia
    Mälardalen University, School of Sustainable Development of Society and Technology.
    Yan, Jinyue
    Mälardalen University, School of Sustainable Development of Society and Technology.
    Influence of drying process on the biomass-based polygeneration system of bioethanol, power and heat2012In: Applied Energy, ISSN 0306-2619, E-ISSN 1872-9118, Vol. 90, no 1/SI, p. 32-37Article in journal (Refereed)
    Abstract [en]

    One of the by-products from bioethanol production using woody materials is lignin solids, which can be utilized as feedstock for combined heat and power (CHP) production. In this paper, the influence of integrating a drying process into a biomass-based polygeneration system is studied, where the exhaust flue gas is used to dry the lignin solids instead of direct condensation in the flue gas condenser (FGC). The evaporated water vapor from the lignin solids is mixed with the drying medium for consequent condensation. Thus, the exhaust flue gas after the drying still has enough humidity to produce roughly the same amount of condensation heat as direct condensation in the existing configuration. The influence of a drying process and how it interacts with the FGC in CHP production as a part of the  polygeneration system is analyzed and evaluated. If a drying process is integrated with the polygeneration system, overall energyefficiency is only increased by 3.1% for CHP plant, though the power output can be increased by 5.5% compared with the simulated system using only FGC.

  • 168.
    Hao, Wenming
    et al.
    Stockholm University, Faculty of Science, Department of Materials and Environmental Chemistry (MMK).
    Björkman, Eva
    Stockholm University, Faculty of Science, Department of Materials and Environmental Chemistry (MMK).
    Lilliestråle, Malte
    Hedin, Niklas
    Stockholm University, Faculty of Science, Department of Materials and Environmental Chemistry (MMK).
    Activated carbons prepared from hydrothermally carbonized waste biomass used as adsorbents for CO22013In: Applied Energy, ISSN 0306-2619, E-ISSN 1872-9118, Vol. 112, p. 526-532Article in journal (Refereed)
    Abstract [en]

    Activated carbons prepared from hydrothermally carbonized (HTC) waste biomass were studied with respect to the adsorption of carbon dioxide. The physically activated carbons (PAC) exhibited a large adsorption of CO2 of 1.45 mmol/g at a small partial pressure of CO2 (10 kPa and a temperature of 0 degrees C). These PACs were prepared by activation in a stream of CO2 and had significant amounts of ultramicropores, which were established by analyzing the adsorption of CO2 with a density functional theory. The uptake at such low pressures of CO2 is of most importance for an adsorption-driven CO2 capture from flue gas at large power stations, as it is difficult to imagine a pressurization of the flue gas. The capacities to adsorb CO2 of the different activated carbons were compared with both the micropore volumes as established by N-2 adsorption, and the ultramicropore volumes as established by CO2 adsorption. The ultramicropore volume is of crucial importance for the capture of CO2 from flue gas. PAC from HTC grass cuttings and from horse manure had the largest ultramicropore volumes. In general, the PAC showed excellent cyclability of adsorption/desorption of CO2 and a minimal capacity loss after subsequent cycles. In addition, the PAC showed a rapid adsorption of CO2. Both characteristics are essential for the eventual use of such PACs in the adsorption driven separation of CO2 from flue gas. A chemically activated carbon (CAC) was prepared by treating hydrothermally carbonized beer waste with H3PO4 and a heat treatment in a flow of N-2. This CAC showed a significant amount of mesopores in the range of 5 nm, in addition to micropores. The apparent selectivity for the activated carbons for CO2-over-N-2 adsorption was determined at 0 degrees C and 10 kPa.

  • 169. Hao, Y.
    et al.
    Li, W.
    Tian, Z.
    Campana, Pietro Elia
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemical Engineering, Energy Processes. School of Business, Society and Engineering, Mälardalen University, SE 72123 Västerås, Sweden.
    Li, H.
    Jin, H.
    Yan, Jinyue
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemical Engineering. School of Business, Society and Engineering, Mälardalen University, SE 72123 Västerås, Sweden.
    Integration of concentrating PVs in anaerobic digestion for biomethane production2018In: Applied Energy, ISSN 0306-2619, E-ISSN 1872-9118, Vol. 231, p. 80-88Article in journal (Refereed)
    Abstract [en]

    Biogas produced from anaerobic digestion processes is considered as an important alternative to natural gas and plays a key role in the emerging market for renewable energy. Aiming at achieving a more sustainable and efficient biomethane production, this work proposed a novel energy system, which integrates concentrating photovoltaic/thermal (C-PV/T) hybrid modules into a biogas plant with chemical absorption for biogas upgrading. The investigated energy system was optimized based on the data from an existing biogas plant, and its techno-economic feasibility was evaluated. Results show that about 7% of the heat consumption and 12% of the electricity consumption of the biogas plant can be covered by solar energy, by using the produced heat in a cascade way according to the operating temperature of different processes. The production of biomethane can also be improved by 25,800 N m3/yr (or 1.7%). The net present value of the integrated system is about 2.78 MSEK and the payback period is around 10 years. In order to further improve the economic performance, it is of great importance to lower the capital cost of the C-PV/T module. 

  • 170.
    Hao, Y.
    et al.
    Institute of Engineering Thermophysics, Chinese Academy of Sciences, Beijing, China.
    Li, W.
    Institute of Engineering Thermophysics, Chinese Academy of Sciences, Beijing, China.
    Tian, Z.
    Institute of Engineering Thermophysics, Chinese Academy of Sciences, Beijing, 100190, China.
    Campana, Pietro Elia
    Mälardalen University, School of Business, Society and Engineering, Future Energy Center. KTH Royal Institute of Technology, Stockholm, Sweden.
    Li, Hailong
    Mälardalen University, School of Business, Society and Engineering, Future Energy Center. Institute of Engineering Thermophysics, Chinese Academy of Sciences, Beijing, China.
    Jin, H.
    Institute of Engineering Thermophysics, Chinese Academy of Sciences, Beijing, China.
    Yan, Jinyue
    Mälardalen University, School of Business, Society and Engineering, Future Energy Center. KTH Royal Institute of Technology, Stockholm, Sweden.
    Integration of concentrating PVs in anaerobic digestion for biomethane production2018In: Applied Energy, ISSN 0306-2619, E-ISSN 1872-9118, ISSN 0306-2619, Vol. 231, p. 80-88Article in journal (Refereed)
    Abstract [en]

    Biogas produced from anaerobic digestion processes is considered as an important alternative to natural gas and plays a key role in the emerging market for renewable energy. Aiming at achieving a more sustainable and efficient biomethane production, this work proposed a novel energy system, which integrates concentrating photovoltaic/thermal (C-PV/T) hybrid modules into a biogas plant with chemical absorption for biogas upgrading. The investigated energy system was optimized based on the data from an existing biogas plant, and its techno-economic feasibility was evaluated. Results show that about 7% of the heat consumption and 12% of the electricity consumption of the biogas plant can be covered by solar energy, by using the produced heat in a cascade way according to the operating temperature of different processes. The production of biomethane can also be improved by 25,800 N m3/yr (or 1.7%). The net present value of the integrated system is about 2.78 MSEK and the payback period is around 10 years. In order to further improve the economic performance, it is of great importance to lower the capital cost of the C-PV/T module. 

  • 171. Hatzigeorgiou, Emmanouil
    et al.
    Polatidis, Heracles
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences.
    Haralambopoulos, Dias
    CO2 emissions, GDP and Energy Intensity: A multivariate cointegration and causality analysis for Greece2011In: Applied Energy, ISSN 0306-2619, E-ISSN 1872-9118Article in journal (Refereed)
  • 172.
    He, Jie
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences, Engineering and Mathematics.
    Zhang, Wennan
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences, Engineering and Mathematics.
    Techno-economic evaluation of thermo-chemical biomass-to-ethanol2011In: Applied Energy, ISSN 0306-2619, E-ISSN 1872-9118, Vol. 88, no 4, p. 1224-1232Article in journal (Refereed)
    Abstract [en]

    Bio-ethanol has received considerable attention as a basic chemical and fuel additive. Bio-ethanol is presently produced from sugar/starch materials, but can also be produced from lignocellulosic biomass via hydrolysis-fermentation route or thermo-chemical route. In terms of thermo-chemical route, a few pilot plants ranging from 0.3 to 67 MW have been built and operated for alcohols synthesis. However, commercial success has not been found. In order to realize cost-competitive commercial ethanol production from lignocellulosic biomass through thermo-chemical pathway, a techno-economic analysis needs to be done. In this paper, a thermo-chemical process is designed, simulated and optimized mainly with ASPEN Plus. The techno-economic assessment is made in terms of ethanol yield, synthesis selectivity, carbon and CO conversion efficiencies, and ethanol production cost. Calculated results show that major contributions to the production cost are from biomass feedstock and syngas cleaning. A biomass-to-ethanol plant should be built around 200 MW. Cost-competitive ethanol production can be realized with efficient equipments, optimized operation, cost-effective syngas cleaning technology, inexpensive raw material with low pretreatment cost, high performance catalysts, off-gas and methanol recycling, optimal systematic configuration and heat integration, and high value byproduct.

  • 173. He, Wei
    et al.
    Hong, Xiaoqiang
    Zhao, Xudong
    Zhang, Xingxing
    University of Hull.
    Shen, Jinchun
    Ji, Jie
    Operational performance of a novel heat pump assisted solar facade loop-heat-pipe water heating system2015In: Applied Energy, ISSN 0306-2619, E-ISSN 1872-9118, Vol. 146, p. 371-382Article in journal (Refereed)
    Abstract [en]

    This paper aims to present an investigation into the operational performance of a novel heat pump assisted solar façade loop-heat-pipe (LHP) water heating system using both theoretical and experimental methods. This involved (1) development of a computer numerical model; (2) simulation of the operational performance of the system by using the model; (3) test rig construction; and (4) dedicated experiment for verification of the model. It was found that the established model is able to predict the operational performance of the system at a reasonable accuracy. Analyses of the research results indicated that under the selected testing conditions, the average thermal efficiency of the LHP module was around 71%, much higher than that of the loop heat pipe without heat pump assistance. The thermal efficiency of the LHP module grew when the heat pump was turned-on and fell when the heat pump was turned-off. The water temperature remained a steadily growing trend throughout the heat pump turned-on period. Neglecting the heat loss of the water tank, the highest coefficient of the performance could reach up to 6.14 and its average value was around 4.93. In overall, the system is a new façade integrated, highly efficient and aesthetically appealing solar water heating configuration; wide deployment of the system will help reduce fossil fuel consumption in the building sector and carbon emission to the environment.

  • 174. He, Wei
    et al.
    Zhang, Gan
    Zhang, Xingxing
    University of Nottingham.
    Ji, Jie
    Li, Guiqiang
    Zhao, Xudong
    Recent development and application of thermoelectric generator and cooler2015In: Applied Energy, ISSN 0306-2619, E-ISSN 1872-9118, Vol. 143, p. 1-25Article in journal (Refereed)
    Abstract [en]

    Energy crisis and environment deterioration are two major problems for 21st century. Thermoelectric device is a promising solution for those two problems. This review begins with the basic concepts of the thermoelectric and discusses its recent material researches about the figure of merit. It also reports the recent applications of the thermoelectric generator, including the structure optimization which significantly affects the thermoelectric generator, the low temperature recovery, the heat resource and its application area. Then it reports the recent application of the thermoelectric cooler including the thermoelectric model and its application area. It ends with the discussion of the further research direction.

  • 175. Hedin, N.
    et al.
    Andersson, L.
    Bergström, L.
    Yan, Jinyue
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Energy Processes.
    Adsorbents for the post-combustion capture of CO2 using rapid temperature swing or vacuum swing adsorption2013In: Applied Energy, ISSN 0306-2619, E-ISSN 1872-9118, Vol. 104, p. 418-433Article in journal (Refereed)
    Abstract [en]

    In general, the post-combustion capture of CO2 is costly; however, swing adsorption processes can reduce these costs under certain conditions. This review highlights the issues related to adsorption-based processes for the capture of CO2 from flue gas. In particular, we consider studies that investigate CO2 adsorbents for vacuum swing or temperature swing adsorption processes. Zeolites, carbon molecular sieves, metal organic frameworks, microporous polymers, and amine-modified sorbents are relevant for such processes. The large-volume gas flows in the gas flue stacks of power plants limit the possibilities of using regular swing adsorption processes, whose cycles are relatively slow. The structuring of CO2 adsorbents is crucial for the rapid swing cycles needed to capture CO2 at large point sources. We review the literature on such structured CO2 adsorbents. Impurities may impact the function of the sorbents, and could affect the overall thermodynamics of power plants, when combined with carbon capture and storage. The heat integration of the adsorption-driven processes with the power plant is crucial in ensuring the economy of the capture of CO2, and impacts the design of both the adsorbents and the processes. The development of adsorbents with high capacity, high selectivity, rapid uptake, easy recycling, and suitable thermal and mechanical properties is a challenging task. These tasks call for interdisciplinary studies addressing this delicate optimization process, including integration with the overall thermodynamics of power plants.

  • 176.
    Hedin, N.
    et al.
    Stockholm University.
    Andersson, L.
    Stockholm University.
    Bergström, L.
    Stockholm University.
    Yan, Jinyue
    Mälardalen University, School of Sustainable Development of Society and Technology.
    Adsorbents for the post-combustion capture of CO2 using rapid temperature swing or vacuum swing adsorption2013In: Applied Energy, ISSN 0306-2619, E-ISSN 1872-9118, Vol. 104, p. 418-433Article in journal (Refereed)
    Abstract [en]

    In general, the post-combustion capture of CO2 is costly; however, swing adsorption processes can reduce these costs under certain conditions. This review highlights the issues related to adsorption-based processes for the capture of CO2 from flue gas. In particular, we consider studies that investigate CO2 adsorbents for vacuum swing or temperature swing adsorption processes. Zeolites, carbon molecular sieves, metal organic frameworks, microporous polymers, and amine-modified sorbents are relevant for such processes. The large-volume gas flows in the gas flue stacks of power plants limit the possibilities of using regular swing adsorption processes, whose cycles are relatively slow. The structuring of CO2 adsorbents is crucial for the rapid swing cycles needed to capture CO2 at large point sources. We review the literature on such structured CO2 adsorbents. Impurities may impact the function of the sorbents, and could affect the overall thermodynamics of power plants, when combined with carbon capture and storage. The heat integration of the adsorption-driven processes with the power plant is crucial in ensuring the economy of the capture of CO2, and impacts the design of both the adsorbents and the processes. The development of adsorbents with high capacity, high selectivity, rapid uptake, easy recycling, and suitable thermal and mechanical properties is a challenging task. These tasks call for interdisciplinary studies addressing this delicate optimization process, including integration with the overall thermodynamics of power plants. © 2012 Elsevier Ltd.

  • 177.
    Hedin, Niklas
    et al.
    Stockholm University, Faculty of Science, Department of Materials and Environmental Chemistry (MMK).
    Andersson, Linnea
    Stockholm University, Faculty of Science, Department of Materials and Environmental Chemistry (MMK).
    Bergström, Lennart
    Stockholm University, Faculty of Science, Department of Materials and Environmental Chemistry (MMK).
    Yan, Jinyue
    Adsorbents for the post-combustion capture of CO2 using rapid temperature swing or vacuum swing adsorption2013In: Applied Energy, ISSN 0306-2619, E-ISSN 1872-9118, Vol. 104, p. 418-433Article in journal (Refereed)
    Abstract [en]

    In general, the post-combustion capture of CO2 is costly; however, swing adsorption processes can reduce these costs under certain conditions. This review highlights the issues related to adsorption-based processes for the capture of CO2 from flue gas. In particular, we consider studies that investigate CO2 adsorbents for vacuum swing or temperature swing adsorption processes. Zeolites, carbon molecular sieves, metal organic frameworks, microporous polymers, and amine-modified sorbents are relevant for such processes. The large-volume gas flows in the gas flue stacks of power plants limit the possibilities of using regular swing adsorption processes, whose cycles are relatively slow. The structuring of CO2 adsorbents is crucial for the rapid swing cycles needed to capture CO2 at large point sources. We review the literature on such structured CO2 adsorbents. Impurities may impact the function of the sorbents, and could affect the overall thermodynamics of power plants, when combined with carbon capture and storage. The heat integration of the adsorption-driven processes with the power plant is crucial in ensuring the economy of the capture of CO2, and impacts the design of both the adsorbents and the processes. The development of adsorbents with high capacity, high selectivity, rapid uptake, easy recycling, and suitable thermal and mechanical properties is a challenging task. These tasks call for interdisciplinary studies addressing this delicate optimization process, including integration with the overall thermodynamics of power plants.

  • 178.
    Hennessy, Jay
    et al.
    RISE - Research Institutes of Sweden, Built Environment, Energy and Circular Economy. Mälardalen University, Sweden.
    Li, Hailong
    Mälardalen University, Sweden.
    Wallin, Fredrik
    Mälardalen University, Sweden.
    Thorin, Eva
    Mälardalen University, Sweden.
    Towards smart thermal grids: Techno-economic feasibility of commercial heat-to-power technologies for district heating2018In: Applied Energy, ISSN 0306-2619, E-ISSN 1872-9118, Vol. 228, p. 766-776Article in journal (Refereed)
    Abstract [en]

    Recent improvements in low-temperature heat-to-power (LTHtP) technologies have led to an increase in efficiency at lower temperatures and lower cost. LTHtP has so far not been used in district heating. The aim of the study is to establish under what conditions the use of existing LTHtP technology is technically and economically feasible using a district heating system as the heat source. The organic Rankine cycle (ORC) is identified as the most interesting LTHtP technology, due to its high relative efficiency and the commercial availability of devices operating at temperatures in the district heating operating range. The levelised cost of electricity of several ORC devices is calculated for temperatures found in district heating, assuming a zero cost of heat. A case study from Sweden is used to calculate the levelised cost of electricity, the net present value and payback period, based on income from the electricity produced, excluding taxes. Hourly spot market electricity prices from 2017 are used, as well as forecast scenarios for 2020, 2030 and 2040. A sensitivity study tests the importance of electricity price, cost of heat and capital/installation cost. Based on the case study, the best levelised cost of electricity achieved was 26.5 EUR/MWh, with a payback period greater than 30 years. Under current Swedish market conditions, the ORC does not appear to be economically feasible for use in district heating, but the net present value and payback period may be significantly more attractive under other countries’ market conditions or with reduced capital costs. For a positive net present value in the Swedish market the capital cost should be reduced to 1.7 EUR/W installed, or the average electricity price should be at least 35.2 EUR/MWh, if the cost of heat is zero. The cost of heat is an important factor in these calculations and should be developed further in future work.

  • 179.
    Hennessy, Jay
    et al.
    Mälardalen University, School of Business, Society and Engineering, Future Energy Center. RISE Research Institutes of Sweden, Borås, Sweden.
    Li, Hailong
    Mälardalen University, School of Business, Society and Engineering, Future Energy Center.
    Wallin, Fredrik
    Mälardalen University, School of Business, Society and Engineering, Future Energy Center.
    Thorin, Eva
    Mälardalen University, School of Business, Society and Engineering, Future Energy Center.
    Towards smart thermal grids: Techno-economic feasibility of commercial heat-to-power technologies for district heating2018In: Applied Energy, ISSN 0306-2619, E-ISSN 1872-9118, Vol. 228, p. 766-776Article in journal (Refereed)
    Abstract [en]

    Recent improvements in low-temperature heat-to-power (LTHtP) technologies have led to an increase in efficiency at lower temperatures and lower cost. LTHtP has so far not been used in district heating. The aim of the study is to establish under what conditions the use of existing LTHtP technology is technically and economically feasible using a district heating system as the heat source. The organic Rankine cycle (ORC) is identified as the most interesting LTHtP technology, due to its high relative efficiency and the commercial availability of devices operating at temperatures in the district heating operating range. The levelised cost of electricity of several ORC devices is calculated for temperatures found in district heating, assuming a zero cost of heat. A case study from Sweden is used to calculate the levelised cost of electricity, the net present value and payback period, based on income from the electricity produced, excluding taxes. Hourly spot market electricity prices from 2017 are used, as well as forecast scenarios for 2020, 2030 and 2040. A sensitivity study tests the importance of electricity price, cost of heat and capital/installation cost. Based on the case study, the best levelised cost of electricity achieved was 26.5 EUR/MWh, with a payback period greater than 30 years. Under current Swedish market conditions, the ORC does not appear to be economically feasible for use in district heating, but the net present value and payback period may be significantly more attractive under other countries’ market conditions or with reduced capital costs. For a positive net present value in the Swedish market the capital cost should be reduced to 1.7 EUR/W installed, or the average electricity price should be at least 35.2 EUR/MWh, if the cost of heat is zero. The cost of heat is an important factor in these calculations and should be developed further in future work.

  • 180.
    Hoggett, R.
    et al.
    University of Exeter, UK.
    Bolton, R.
    University of Edinburgh, UK.
    Candelise, C.
    Imperial College London, UK.
    Kern, F.
    University of Sussex, UK.
    Mitchell, C.
    University of Exeter, UK.
    Yan, Jinyue
    Mälardalen University, School of Business, Society and Engineering. Mälardalen University, School of Business, Society and Engineering, Future Energy Center.
    Supply chains and energy security in a low carbon transition2014In: Applied Energy, ISSN 0306-2619, E-ISSN 1872-9118, Vol. 123, p. 292-295Article in journal (Other academic)
  • 181. Hoggett, Richard
    et al.
    Bolton, Ronan
    Candelise, Chiara
    Kern, Florian
    Mitchell, Catherine
    Yan, Jinyue
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Energy Processes.
    Supply chains and energy security in a low carbon transition2014In: Applied Energy, ISSN 0306-2619, E-ISSN 1872-9118, Vol. 123, p. 292-295Article in journal (Refereed)
  • 182.
    Hosain, Md Lokman
    et al.
    Mälardalen University, School of Business, Society and Engineering, Future Energy Center. ABB AB, Corporate Research, Västerås, Sweden.
    Bel Fdhila, Rebei
    Mälardalen University, School of Business, Society and Engineering, Future Energy Center. ABB AB, Corporate Research, Västerås, Sweden.
    Daneryd, Anders
    ABB AB, Corporate Research, Västerås, Sweden.
    Heat transfer by liquid jets impinging on a hot flat surface2016In: Applied Energy, ISSN 0306-2619, E-ISSN 1872-9118, Vol. 164, no 15, p. 934-943Article in journal (Refereed)
    Abstract [en]

    Runout Table (ROT) cooling is one of the most important factors for controlling quality of hot rolled steel. ROT cooling uses large quantities of water to cool the steel plate. Optimizing heat transfer in the ROT would reduce the amount of water used, which will lower the amount of energy needed for pumping, filtering, storage and use of water. Optimization will therefore result in a direct energy saving as well as increasing the product quality.

    This study investigates heat transfer by turbulent water jets impinging on a hot flat steel plate at temperatures below the boiling point in order to understand convection heat transfer phenomena. This is an important stage that precedes the boiling and addresses the applicability of the heat transfer correlations available in the literature.

    A single axisymmetric jet and a pair of interacting jets are simulated using Computational Fluid Dynamics (CFD). The Reynolds Averaged Navier Stokes (RANS) model under steady and transient conditions and the kɛ turbulence model are used in both 2D axisymmetric and 3D simulations. We investigate the influence of the water flow rate on the jet cooling characteristics and develop a correlation for the radial position of the maximum Nusselt number based on numerical results.

    Two sets of boundary conditions – constant temperature and constant heat flux – are applied at the surface of the steel plate and evaluated. The single jet numerical results compare favourably with published data based on measurements and analytical models. The thermal performance of a two-jet system was found to be no better than a single jet because the jets were too far from each other to generate any additional thermal interaction.

  • 183.
    Hosain, Md Lokman
    et al.
    Mälardalen University, School of Business, Society and Engineering, Future Energy Center.
    Bel Fdhila, Rebei
    Mälardalen University, School of Business, Society and Engineering, Future Energy Center.
    Kristian, Rönnberg
    ABB AB, Corporate Research, Sweden.
    Taylor-Couette flow and transient heat transfer inside the annulus air-gap of rotating electrical machines2017In: Applied Energy, ISSN 0306-2619, E-ISSN 1872-9118, Vol. 207, p. 624-633Article in journal (Refereed)
    Abstract [en]

    Losses in an electric motor amount to between 4–24% of the total electrical power, and are converted to heat. The maximum hot spot temperature is one of the design constraints of thermal and electrical performance. Several studies have explored flow and thermal characteristics inside the air-gap between two concentric rotating cylinders such as those found in electric motors, however the transient flow and thermal effects still remain a challenge. This study uses Computational Fluid Dynamics to predict the thermal behaviour of a machine rotating at the kind of speed usually encountered in motors. The Reynolds Averaged Navier-Stokes model together with the realizable k-ε turbulence model are used to perform transient simulations. Velocity profiles and temperature distribution inside the air-gap are obtained and validated. The transient flow features and their impact on thermal performance are discussed. The numerical results show turbulent Taylor vortices inside the air-gap that lead to a periodic temperature distribution. When compared to correlations from published literature, the simulated average heat transfer coefficient at the rotor surface shows overall good agreement. The transient effects introduce local impacts like oscillations to the Taylor-Couette vortices. These flow oscillations result in oscillations of the hotspots. However, this transient oscillatory behaviour does not show any additional impact on the global thermal performance.

  • 184.
    Hosain, Md Lokman
    et al.
    Mälardalen University, School of Business, Society and Engineering, Future Energy Center. ABB AB, Corporate Research, Sweden.
    Domínguez, J. M.
    EPHYSLAB Environmental Physics Laboratory, Universidade de Vigo, Spain.
    Bel Fdhila, Rebei
    Mälardalen University, School of Business, Society and Engineering, Future Energy Center. ABB AB, Corporate Research, Västerås, Sweden.
    Kyprianidis, Konstantinos
    Mälardalen University, School of Business, Society and Engineering, Future Energy Center.
    Smoothed particle hydrodynamics modeling of industrial processes involving heat transfer2019In: Applied Energy, ISSN 0306-2619, E-ISSN 1872-9118, Vol. 252, article id 113441Article in journal (Refereed)
    Abstract [en]

    Smoothed Particle Hydrodynamics (SPH) is a mesh-free particle method that has been widely used over the past decade to model complex flows. The method has mainly been used to investigate problems related to hydrodynamics and maritime engineering, in which heat transfer does not play a key role. In this article, the heat-conduction equation is implemented in the open-source code DualSPHysics, based on the SPH technique, and applied to different study cases, including conduction in still water in a cavity, laminar water flow between two infinite parallel plates and tube bank heat exchanger. The thermal solutions obtained from SPH are benchmarked with the solutions from Finite Volume Method (FVM) and validated using available analytical solutions. DualSPHysics results are in good agreement with FVM and analytical models, and demonstrate the potential of the meshless approach for industrial applications involving heat transfer.

  • 185. Hu, X
    et al.
    Murgovski, N
    Johannesson Mårdh, L
    RISE, Swedish ICT, Viktoria.
    Egardt, B
    Energy Efficiency Analysis of a Series Plug-in Hybrid Electric Bus with Different Energy Management Strategies Battery Sizes2013In: Applied Energy, ISSN 0306-2619, E-ISSN 1872-9118, Vol. 111, p. 1001-Article in journal (Refereed)
    Abstract [en]

    This paper is concerned with the tank-to-wheel (TTW) analysis of a series plug-in hybrid_x000D_ electric bus operating in Gothenburg, Sweden. The bus line the powertrain model are described._x000D_ The definition the calculation method of the recuperation fuel-to-traction efficiencies are_x000D_ delineated for evaluating the TTW energy conversion. The two efficiencies are quantified and_x000D_ compared for two optimization-based energy management strategies, in which convex modeling and_x000D_ optimization are used. The impact of downsizing the battery on the two efficiencies is also investigated._x000D_

  • 186.
    Hu, Y.
    et al.
    Royal Institute of Technology, Sweden.
    Li, Hailong
    Mälardalen University, School of Business, Society and Engineering, Future Energy Center.
    Yan, Jinyue
    Mälardalen University, School of Business, Society and Engineering, Future Energy Center. Royal Institute of Technology, Sweden.
    Numerical investigation of heat transfer characteristics in utility boilers of oxy-coal combustion2014In: Applied Energy, ISSN 0306-2619, E-ISSN 1872-9118, Vol. 130, no 1, p. 543-551Article in journal (Refereed)
    Abstract [en]

    Oxy-coal combustion has different flue gas composition from the conventional air-coal combustion. The different composition further results in different properties, such as the absorption coefficient, emissivity, and density, which can directly affect the heat transfer in both radiation and convection zones of utility boilers. This paper numerically studied a utility boiler of oxy-coal combustion and compares with air-coal combustion in terms of flame profile and heat transferred through boiler side walls in order to understand the effects of different operating conditions on oxy-coal boiler retrofitting and design. Based on the results, it was found that around 33vol% of effective O2 concentration ([O2]effective) the highest flame temperature and total heat transferred through boiler side walls in the oxy-coal combustion case match to those in the air-coal combustion case most; therefore, the 33vol% of [O2]effective could result in the minimal change for the oxy-coal combustion retrofitting of the existing boiler. In addition, the increase of the moisture content in the flue gas has little impact on the flame temperature, but results in a higher surface incident radiation on boiler side walls. The area of heat exchangers in the boiler was also investigated regarding retrofitting. If boiler operates under a higher [O2]effective, to rebalance the load of each heat exchanger in the boiler, the feed water temperature after economizer can be reduced or part of superheating surfaces can be moved into the radiation zone to replace part of the evaporators

  • 187.
    Hu, Y.
    et al.
    Royal Institute of Technology .
    Li, X.
    Tianjin University, School of Mechanical Engineering, China .
    Li, Hailong
    Mälardalen University, School of Business, Society and Engineering.
    Yan, Jinyue
    Mälardalen University, School of Business, Society and Engineering.
    Peak and off-peak operations of the air separation unit in oxy-coal combustion power generation systems2013In: Applied Energy, ISSN 0306-2619, E-ISSN 1872-9118, Vol. 112, p. 747-754Article in journal (Refereed)
    Abstract [en]

    Introducing CO2 capture and storage (CCS) into the power systems requires the re-investigation of the load balance for the electrical grid. For the oxy-coal combustion capture technology, the energy use of ASU can be shifted between the peak-load and off-peak-load periods, which may bring more benefits. In this paper, peak and off-peak (POP) operations for the air separation unit (ASU) with liquid oxygen storage were studied based on a 530MW coal-fired power system. According to the simulation results, the oxy-coal combustion power system running POP is technically feasible that it can provide a base load of 496MW during the off-peak period and a peak load of 613MW during the peak period. And the equivalent efficiency of the power system running POP is only 0.3% lower than the one not running POP. Moreover, according to the economic assessments based on the net present value, it is also economically feasible that the payback time of the investment of the oxy-coal combustion power system running POP is about 13years under the assumptions of 10% discount rate and 2.5% cost escalation rate. In addition, the effects of the difference of on-grid electricity prices, daily peak period, investment for POP operations, and ASU energy consumption were also analyzed, concerning the net present value.

  • 188.
    Hu, Yukun
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Energy Processes.
    Li, Hailong
    Yan, Jinyue
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Energy Processes. Malardalen Univ, Sch Sustainable Dev Soc & Technol, SE-72123 Vasteras, Sweden.
    Numerical investigation of heat transfer characteristics in utility boilers of oxy-coal combustion2014In: Applied Energy, ISSN 0306-2619, E-ISSN 1872-9118, Vol. 130, p. 543-551Article in journal (Refereed)
    Abstract [en]

    Oxy-coal combustion has different flue gas composition from the conventional air-coal combustion. The different composition further results in different properties, such as the absorption coefficient, emissivity, and density, which can directly affect the heat transfer in both radiation and convection zones of utility boilers. This paper numerically studied a utility boiler of oxy-coal combustion and compares with air-coal combustion in terms of flame profile and heat transferred through boiler side walls in order to understand the effects of different operating conditions on oxy-coal boiler retrofitting and design. Based on the results, it was found that around 33 vol% of effective O-2 concentration ([O-2](effective)) the highest flame temperature and total heat transferred through boiler side walls in the oxy-coal combustion case match to those in the air-coal combustion case most; therefore, the 33 vol% of [O-2](effective) could result in the minimal change for the oxy-coal combustion retrofitting of the existing boiler. In addition, the increase of the moisture content in the flue gas has little impact on the flame temperature, but results in a higher surface incident radiation on boiler side walls. The area of heat exchangers in the boiler was also investigated regarding retrofitting. If boiler operates under a higher [O-2](effective), to rebalance the load of each heat exchanger in the boiler, the feed water temperature after economizer can be reduced or part of superheating surfaces can be moved into the radiation zone to replace part of the evaporators.

  • 189.
    Hu, Yukun
    et al.
    Royal Inst Technol.
    Li, Hailong
    Mälardalen University, School of Sustainable Development of Society and Technology.
    Yan, Jinyue
    Mälardalen University, School of Sustainable Development of Society and Technology.
    Techno-economic evaluation of the evaporative gas turbine cycle with different CO(2) capture options2012In: Applied Energy, ISSN 0306-2619, E-ISSN 1872-9118, Vol. 89, no 1, p. 303-314Article in journal (Refereed)
    Abstract [en]

    The techno-economic evaluation of the evaporative gas turbine (EvGT) cycle with two different CO(2) capture options has been carried out. Three studied systems include a reference system: the EvGT system without CO(2) capture (System I), the EvGT system with chemical absorption capture (System II), and the EvGT system with oxyfuel combustion capture (System III). The cycle simulation results show that the system with chemical absorption has a higher electrical efficiency (41.6% of NG LHV) and a lower efficiency penalty caused by CO(2) capture (10.5% of NG LHV) compared with the system with oxyfuel combustion capture. Based on a gas turbine of 13.78 MW, the estimated costs of electricity are 46.1 $/MW h for System I. while 70.1 $/MW h and 74.1 $/MW h for Systems II and III, respectively. It shows that the cost of electricity increment of chemical absorption is 8.7% points lower than that of the option of oxyfuel combustion. In addition, the cost of CO(2) avoidance of System II which is 71.8 $/tonne CO(2) is also lower than that of System III, which is 73.2 $/tonne CO(2). The impacts of plant size have been analyzed as well. Results show that cost of CO(2) avoidance of System III may be less than that of System II when a plant size is larger than 60 MW.

  • 190.
    Hu, Yukun
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Energy Processes.
    Li, Hailong
    Mälardalen University, School of Sustainable Development of Society and Technology, Västerås, Sweden.
    Yan, Jinyue
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Energy Processes.
    Techno-economic evaluation of the evaporative gas turbine cycle with different CO2 capture options2012In: Applied Energy, ISSN 0306-2619, E-ISSN 1872-9118, Vol. 89, no 1, p. 303-314Article in journal (Refereed)
    Abstract [en]

    The techno-economic evaluation of the evaporative gas turbine (EvGT) cycle with two different CO2 capture options has been carried out. Three studied systems include a reference system: the EvGT system without CO2 capture (System I), the EvGT system with chemical absorption capture (System II), and the EvGT system with oxyfuel combustion capture (System III). The cycle simulation results show that the system with chemical absorption has a higher electrical efficiency (41.6% of NG LHV) and a lower efficiency penalty caused by CO2 capture (10.5% of NG LHV) compared with the system with oxyfuel combustion capture. Based on a gas turbine of 13.78 MW, the estimated costs of electricity are 46.1 $/MW h for System I, while 70.1 $/MW h and 74.1 $/MW h for Systems II and III, respectively. It shows that the cost of electricity increment of chemical absorption is 8.7% points lower than that of the option of oxyfuel combustion. In addition, the cost of CO2 avoidance of System II which is 71.8 $/tonne CO2 is also lower than that of System III, which is 73.2 $/tonne CO2. The impacts of plant size have been analyzed as well. Results show that cost of CO2 avoidance of System III may be less than that of System II when a plant size is larger than 60 MW.

  • 191.
    Hu, Yukun
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Energy Processes.
    Li, Xun
    Li, Hailong
    Yan, Jinyue
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Energy Processes.
    Peak and off-peak operations of the air separatino unit in oxy-fuel combustion power generation systems2013In: Applied Energy, ISSN 0306-2619, E-ISSN 1872-9118, Vol. 112, no SI, p. 747-754Article in journal (Refereed)
    Abstract [en]

    Introducing CO2 capture and storage (CCS) into the power systems requires the re-investigation of the load balance for the electrical grid. For the oxy-coal combustion capture technology, the energy use of ASU can be shifted between the peak-load and off-peak-load periods, which may bring more benefits. In this paper, peak and off-peak (POP) operations for the air separation unit (ASU) with liquid oxygen storage were studied based on a 530 MW coal-fired power system. According to the simulation results, the oxy-coal combustion power system running POP is technically feasible that it can provide a base load of 496 MW during the off-peak period and a peak load of 613 MW during the peak period. And the equivalent efficiency of the power system running POP is only 0.3% lower than the one not running POP. Moreover, according to the economic assessments based on the net present value, it is also economically feasible that the payback time of the investment of the oxy-coal combustion power system running POP is about 13 years under the assumptions of 10% discount rate and 2.5% cost escalation rate. In addition, the effects of the difference of on-grid electricity prices, daily peak period, investment for POP operations, and ASU energy consumption were also analyzed, concerning the net present value.

  • 192.
    Hu, Yukun
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Energy Processes.
    Yan, Jinyue
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Energy Processes.
    Characterization of flue gas in oxy-coal combustion processes for CO2 capture2012In: Applied Energy, ISSN 0306-2619, E-ISSN 1872-9118, Vol. 90, no 1, p. 113-121Article in journal (Refereed)
    Abstract [en]

    Oxy-coal combustion is one of the technical solutions for mitigating CO2 in thermal power plants. For designing a technically viable and economically effective CO2 capture process, effects by coals and configurations of flue gas cleaning steps are of importance. In this paper, characterization of the flue gas recycle (FGR) is conducted for an oxy-coal combustion process. Different configurations of FGR as well as cleaning units including electrostatic precipitators (ESP), flue gas desulfurization (FGD), selective catalytic reduction (SCR) deNOx and flue gas condensation (FGC) are studied for the oxy-coal combustion process. In addition, other important parameters such as FGR rate and FGR ratio, flue gas compositions, and load of flue gas cleaning units are analyzed based on coal properties and plant operational conditions.

  • 193.
    Hu, Yukun
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Energy Processes.
    Yan, Jinyue
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Energy Processes.
    Li, H.
    Effects of flue gas recycle on oxy-coal power generation systems2012In: Applied Energy, ISSN 0306-2619, E-ISSN 1872-9118, Vol. 97, p. 255-263Article in journal (Refereed)
    Abstract [en]

    This paper examined and assessed various configuration options about emission removal including particles, SO x and NO x in an oxy-coal combustion system for CO 2 capture. A performance analysis was conducted in order to understand the impacts of those options concerning process design, process operation and system efficiency. Results show that different flue gas recycle options have clear effects on the emissivity and absorptivity of radiating gases in boiler due to the change of flue gas compositions. The maximum difference amongst various options can be up to 15% and 20% for emissivity and absorptivity respectively. As a result, the heat transfer by radiation can vary about 20%. The recycle options also have impacts on the design of air heater and selective-catalytic-reduction (SCR) preheater. This is due to that the largely varied operating temperatures in different options may result in different required areas of heat exchangers. In addition, the dew point of flue gas and the boiler efficiency are affected by the configurations of flue gas recycle as well.

  • 194.
    Hu, Yukun
    et al.
    Royal Inst Technol .
    Yan, Jinyue
    Mälardalen University, School of Sustainable Development of Society and Technology.
    Li, Hailong
    Effects of flue gas recycle on oxy-coal power generation system2012In: Applied Energy, ISSN 0306-2619, E-ISSN 1872-9118, Vol. 97, no SI, p. 255-263Article in journal (Refereed)
    Abstract [en]

    This paper examined and assessed various configuration options about emission removal including particles. SOx and NOx in an oxy-coal combustion system for CO2 capture. A performance analysis was conducted in order to understand the impacts of those options concerning process design, process operation and system efficiency. Results show that different flue gas recycle options have clear effects on the emissivity and absorptivity of radiating gases in boiler due to the change of flue gas compositions. The maximum difference amongst various options can be up to 15% and 20% for emissivity and absorptivity respectively. As a result, the heat transfer by radiation can vary about 20%. The recycle options also have impacts on the design of air heater and selective-catalytic-reduction (SCR) preheater. This is due to that the largely varied operating temperatures in different options may result in different required areas of heat exchangers. In addition, the dew point of flue gas and the boiler efficiency are affected by the configurations of flue gas recycle as well.

  • 195.
    Huang, Pei
    et al.
    Dalarna University, School of Technology and Business Studies, Energy Technology.
    Copertaro, Benedetta
    Dalarna University, School of Technology and Business Studies, Energy Technology.
    Zhang, Xingxing
    Dalarna University, School of Technology and Business Studies, Energy Technology.
    Shen, Jingchun
    Dalarna University, School of Technology and Business Studies, Construction.
    Löfgren, Isabelle
    Rönnelid, Mats
    Dalarna University, School of Technology and Business Studies, Energy Technology.
    Fahlen, Jan
    Andersson, Dan
    Svanfeldt, Mikael
    A review of data centers as prosumers in district energy systems: Renewable energy integration and waste heat reuse for district heating2020In: Applied Energy, ISSN 0306-2619, E-ISSN 1872-9118, Vol. 258, article id 114109Article in journal (Refereed)
    Abstract [en]

    As large energy prosumers in district energy systems, on the one hand, data centers consume a large amount of electricity to ensure the Information Technologies (IT) facilities, ancillary power supply and cooling systems work properly; on the other hand, data centers produce a large quantity of waste heat due to the high heat dissipation rates of the IT facilities. To date, a systematic review of data centers from the perspective of energy prosumers, which considers both integration of the upstream green energy supply and downstream waste heat reuse, is still lacking. As a result, the potentials for improving data centers’ performances are limited due to a lack of global optimization of the upstream renewable energy integration and downstream waste heat utilization. This study is intended to fill in this gap and provides such a review. In this regard, the advancements in different cooling techniques, integration of renewable energy and advanced controls, waste heat utilization and connections for district heating, real projects, performance metrics and economic, energy and environmental analyses are reviewed. Based on the enormous amount of research on data centers in district energy systems, it has been found that: (1) global controls, which can manage the upstream renewable production, data centers’ operation and waste heat generation and downstream waste heat utilization are still lacking; (2) regional climate studies represent an effective way to find the optimal integration of renewable energy and waste heat recovery technologies for improving the data centers’ energy efficiency; (3) the development of global energy metrics will help to appropriately quantify the data center performances.

  • 196.
    Huang, Pei
    et al.
    Dalarna University, School of Technology and Business Studies, Energy Technology. City University of Hong Kong.
    Fan, C
    Zhang, Xingxing
    Dalarna University, School of Technology and Business Studies, Energy Technology.
    Wang, J
    A hierarchical coordinated demand response control for buildings with improved performances at building group2019In: Applied Energy, ISSN 0306-2619, E-ISSN 1872-9118, Vol. 242, p. 684-694Article in journal (Refereed)
    Abstract [en]

    Demand response control is one of the common means used for building peak demand limiting. Most of the existing demand response controls focused on single building’s performance optimization, and thus may cause new undesirable peak demands at building group, imposing stress on the grid power balance and limiting the economic savings. A few latest studies have demonstrated the potential benefits of demand response coordination, but the proposed methods cannot be applied in large scales. The main reason is that, for demand response coordination of multiple buildings, associated computational load and coordination complexity, increasing exponentially with building number, are challenges to be solved. This study, therefore, proposes a hierarchical demand response control to optimize operations of a large scale of buildings for group-level peak demand reduction. The hierarchical control first considers the building group as a ‘virtual’ building and searches the optimal performance that can be achieved at building group using genetic algorithm. To realize such optimal performance, it then coordinates each single building’s operation using non-linear programming. For validations, the proposed method has been applied on a case building group, and the study results show that the hierarchical control can overcome the challenges of excessive computational load and complexity. Moreover, in comparison with conventional independent control, it can achieve better performances in aspects of peak demand reduction and economic savings. This study provides a coordinated control for application in large scales, which can improve the effectiveness and efficiency in relieving the grid stress, and reduce the end-users’ electricity bills.

  • 197.
    Huang, Pei
    et al.
    City University of Hong Kong.
    Huang, Gongsheng
    Sun, Yongjun
    Uncertainty-based life-cycle analysis of near-zero energy buildings for performance improvements2018In: Applied Energy, ISSN 0306-2619, E-ISSN 1872-9118, Vol. 213, p. 486-498Article in journal (Refereed)
    Abstract [en]

    Near-zero energy buildings (nZEBs) are considered as an effective solution to mitigating CO2 emissions and reducing the energy usage in the building sector. A proper sizing of the nZEB systems (e.g. HVAC systems, energy supply systems, energy storage systems, etc.) is essential for achieving the desired annual energy balance, thermal comfort, and grid independence. Two significant factors affecting the sizing of nZEB systems are the uncertainties confronted by the building usage condition and weather condition, and the degradation effects in nZEB system components. The former factor has been studied by many researchers; however, the impact of degradation is still neglected in most studies. Degradation is prevalent in energy components of nZEB and inevitably leads to the deterioration of nZEB life-cycle performance. As a result, neglecting the degradation effects may lead to a system design which can only achieve the desired performance at the beginning several years. This paper, therefore, proposes a life-cycle performance analysis (LCPA) method for investigating the impact of degradation on the longitudinal performance of the nZEBs. The method not only integrates the uncertainties in predicting building thermal load and weather condition, but also considers the degradation in the nZEB systems. Based on the proposed LCPA method, a two-stage method is proposed to improve the sizing of the nZEB systems. The study can improve the designers’ understanding of the components’ degradation impacts and the proposed method is effective in the life-cycle performance analysis and improvements of nZEBs. It is the first time that the impacts of degradation and uncertainties on nZEB LCP are analysed. Case studies show that an nZEB might not fulfil its definition at all after some years due to component degradation, while the proposed two-stage design method can effectively alleviate this problem.

  • 198.
    Huang, Pei
    et al.
    Dalarna University, School of Technology and Business Studies, Energy Technology.
    Lovati, Marco
    Dalarna University, School of Technology and Business Studies, Energy Technology.
    Zhang, Xingxing
    Dalarna University, School of Technology and Business Studies, Energy Technology.
    Bales, Chris
    Dalarna University, School of Technology and Business Studies, Energy Technology.
    A coordinated control to improve performance for a building cluster withenergy storage, electric vehicles, and energy sharing considered2020In: Applied Energy, ISSN 0306-2619, E-ISSN 1872-9118, Vol. 268, article id 114983Article in journal (Refereed)
  • 199.
    Huang, Pei
    et al.
    Dalarna University, School of Technology and Business Studies, Energy Technology.
    Lovati, Marco
    EURAC Research, Bolzano, Italy; University of Trento, Trento, Italy.
    Zhang, Xingxing
    Dalarna University, School of Technology and Business Studies, Energy Technology.
    Bales, Chris
    Dalarna University, School of Technology and Business Studies, Energy Technology.
    Hallbeck, Sven
    NIBE Climate Solutions, Sweden.
    Becker, Anders
    Ferroamp Elektronik AB, Spånga, Sweden.
    Bergqvist, Henrik
    LudvikaHem AB Bobutiken, Ludvika, Sweden.
    Hedberg, Jan
    LudvikaHem AB Bobutiken, Ludvika, Sweden.
    Maturi, Laura
    EURAC Research, Bolzano, Italy.
    Transforming a residential building cluster into electricity prosumers in Sweden: Optimal design of a coupled PV-heat pump-thermal storage-electric vehicle system2019In: Applied Energy, ISSN 0306-2619, E-ISSN 1872-9118, Vol. 255, article id 113864Article in journal (Refereed)
    Abstract [en]

    Smart grid is triggering the transformation of traditional electricity consumers into electricity prosumers. This paper reports a case study of transforming an existing residential cluster in Sweden into electricity prosumers. The main energy concepts include (1) click-and-go photovoltaics (PV) panels for building integration, (2) centralized exhaust air heat pump, (3) thermal energy storage for storing excess PV electricity by using heat pump, and (4) PV electricity sharing within the building cluster for thermal/electrical demand (including electric vehicles load) on a direct-current micro grid. For the coupled PV-heat pump-thermal storage-electric vehicle system, a fitness function based on genetic algorithm is established to optimize the capacity and positions of PV modules at cluster level, with the purpose of maximizing the self-consumed electricity under a non-negative net present value during the economic lifetime. Different techno-economic key performance indicators, including the optimal PV capacity, self-sufficiency, self-consumption and levelized cost of electricity, are analysed under impacts of thermal storage integration, electric vehicle penetration and electricity sharing possibility. Results indicate that the coupled system can effectively improve the district-level PV electricity self-consumption rate to about 77% in the baseline case. The research results reveal how electric vehicle penetrations, thermal storage, and energy sharing affect PV system sizing/positions and the performance indicators, and thus help promote the PV deployment. This study also demonstrates the feasibility for transferring the existing Swedish building clusters into smart electricity prosumers with higher self-consumption and energy efficiency and more intelligence, which benefits achieving the ‘32% share of renewable energy source’ target in EU by 2030.

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  • 200.
    Huang, Pei
    et al.
    Dalarna University, School of Technology and Business Studies, Energy Technology. City University of Hong Kong.
    Ma, Z.
    Xiao, L.
    Sun, Y.
    Geographic Information System-assisted optimal design of renewable powered electric vehicle charging stations in high-density cities2019In: Applied Energy, ISSN 0306-2619, E-ISSN 1872-9118, Vol. 255, article id 113855Article in journal (Refereed)
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