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  • 51.
    Guan, Tingting
    et al.
    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.
    Lindbergh, Göran
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Applied Electrochemistry.
    Investigation of the prospect of energy self-sufficiency and technical performance of an integrated PEMFC (proton exchange membrane fuel cell), dairy farm and biogas plant system2014In: Applied Energy, ISSN 0306-2619, E-ISSN 1872-9118, Vol. 130, p. 685-691Article in journal (Refereed)
    Abstract [en]

    A PEMFC fuelled with hydrogen is known for its high efficiency and low local emissions. However, the generation of hydrogen is always a controversial issue for the application of the PEMFC due to the use of fossil fuel and the possible carbon dioxide emissions. Presently, the PEMFC-CHP fed with renewable fuels, such as biogas, appears to be the most attractive energy converter-fuel combination. In this paper, an integrated PEMFC-CHP, a dairy farm and a biogas plant are studied. A PEMFC-CHP fed with reformate gas from the biogas plant generates electricity and heat to a dairy farm and a biogas plant, while the dairy farm delivers wet manure to the biogas plant as the feedstock for biogas production. This integrated system has been modelled for steady-state conditions by using Aspen Plus (R). The results indicate that the wet manure production of a dairy farm with 300 milked cows can support a biogas plant to give 1280 MW h of biogas annually. Based on the biogas production, a PEMFC-CHP with a stack having an electrical efficiency of 40% generates 360 MW h electricity and 680 MW h heat per year, which is enough to cover the energy demand of the whole system while the total efficiency of the PEMFC-CHP system is 82%. The integrated PEMFC-CHP, dairy farm and biogas plant could make the dairy farm and the biogas plant self-sufficient in a sustainable way provided the PEMFC-CHP has the electrical efficiency stated above. The effect of the methane conversion rate and the biogas composition on the system performance is discussed. Moreover, compared with the coal-fired CUP plant, the potentially avoided fossil fuel consumption and CO2 emissions of this self-sufficient system are also calculated.

  • 52.
    Gunarathne, Duleeka S.
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering.
    Mellin, Pelle
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering.
    Yang, Weihong
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering. Swerea KIMAB AB, Sweden.
    Pettersson, M.
    Ljunggren, R.
    Performance of an effectively integrated biomass multi-stage gasification system and a steel industry heat treatment furnace2016In: Applied Energy, ISSN 0306-2619, E-ISSN 1872-9118, Vol. 170, p. 353-361Article in journal (Refereed)
    Abstract [en]

    The challenges of replacing fossil fuel with renewable energy in steel industry furnaces include not only reducing CO2 emissions but also increasing the system energy efficiency. In this work, a multi-stage gasification system is chosen for the integration with a heat treatment furnace in the steel powder industry to recover different rank/temperature waste heat back to the biomass gasification system, resulting higher system energy efficiency.A system model based on Aspen Plus was developed for the proposed integrated system considering all steps, including biomass drying, pyrolysis, gasification and the combustion of syngas in the furnace. Both low temperature (up to 400 °C) and high temperature (up to 700 °C) heat recovery possibilities were analysed in terms of energy efficiency by optimizing the biomass pretreatment temperature.The required process conditions of the furnace can be achieved by using syngas. No major changes to the furnace, combustion technology or flue gas handling system are necessary for this fuel switching. Only a slight revamp of the burner system and a new waste heat recovery system from the flue gases are required.Both the furnace efficiency and gasifier system efficiency are improved by integration with the waste heat recovery. The heat recovery from the hot furnace flue gas for biomass drying and steam superheating is the most promising option from an energy efficiency point of view. This option recovers two thirds of the available waste heat, according to the pinch analysis performed. Generally, depending on the extent of flue gas heat recovery, the system can sustain up to 65% feedstock moisture content at the highest pyrolysis temperature studied.

  • 53.
    Gunarathne, Duleeka Sandamali
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Energy and Furnace Technology.
    Chmielewski, Jan Karol
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Energy and Furnace Technology.
    Yang, Weihong
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Energy and Furnace Technology.
    Pressure drop prediction of a gasifier bed with cylindrical biomass pellets2014In: Applied Energy, ISSN 0306-2619, E-ISSN 1872-9118, Vol. 113, p. 258-266Article in journal (Refereed)
    Abstract [en]

    Bed pressure drop is an import parameter related to operation and performance of fixed bed gasifiers. Up to date, limited literature is found on pressure drop prediction of beds with cylindrical pellets and none was found for gasifying beds with cylindrical pellets. In this paper, an available pressure drop prediction correlation for turbulent flows in a bed with cylindrical pellets which has used equivalent tortuous passage method was extended for a gasifier bed with shrinking cylindrical pellets and for any flow condition. Further, simplified graphical representations introduced based on the developed correlation can be effectively used as a guide for selecting a suitable pellet size and designing a grate so that it can be met the system requirements. Results show that the method formulated in the present study gives pressure drop approximation within 7% deviation compared to measured values with respect to performed runs. Available empirical correlation with modified Ergun constants for cylindrical pellets gave pressure drop within 20% deviation after the effect of shrinkage was taken into account.

  • 54.
    Gunasekara, Saman Nimali
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
    Pan, Ruijun
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology. Department of Chemistry, Ångström Laboratory, Uppsala University, Box 538 75121 Uppsala, Sweden.
    Chiu, Justin NingWei
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
    Martin, Viktoria
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology.
    Polyols as phase change materials for surplus thermal energy storage2016In: Applied Energy, ISSN 0306-2619, E-ISSN 1872-9118, Vol. 162, p. 1439-1452Article in journal (Refereed)
    Abstract [en]

    Storing low-temperature surplus thermal energy from industries, power plants, and the like, using phasechange materials (PCM) is an effective alternative in alleviating the use of fossil based thermal energyprovision. Polyols; of some also known as sugar alcohols, are an emerging PCM category for thermalenergy storage (TES). A review on polyols as PCM for TES shows that polyols have phase change temperaturesin the range of 15 to 245 C, and considerable phase change enthalpies of 100–413 kJ/kg. However,the knowledge on the thermo-physical properties of polyols as desirable PCM for TES design is presentlysparse and rather inconsistent. Moreover, the phase change and state change behaviors of polyols need tobe better-understood in order to use these as PCM; e.g. the state change glass transition which manypolyols at pure state are found to undergo. In this work preliminary material property characterizationwith the use of Temperature-History method of some selected polyols, Erythritol, Xylitol andPolyethylene glycol (PEG) 10,000 were done. Complex behaviors were observed for some of the polyols.These are: two different melting temperatures, 118.5–120 C and 106–108 C at different cycles and anaverage subcooling 18.5 C of for Erythritol, probable glass-transition between 0 and 113 C for Xylitol,as well as a thermally activated change that is likely an oxidation, after three to five heating/coolingcycles for Xylitol and Erythritol. PEG 10,000 had negligible subcooling, no glass-transition nor thermallyactivated oxidation. However a hysteresis of around 10 C was observed for PEG 10,000. Therefore thesematerials require detailed studies to further evaluate their PCM-suitability. This study is expected to be an initiation of an upcoming extensive polyol-blends phase equilibrium evaluation.

  • 55.
    Guo, Guodong
    et al.
    State Grid Economic and Technological Research Institute Co., Ltd., Beijing 102209, China.
    Zhang, Mengfan
    KTH, School of Electrical Engineering and Computer Science (EECS), Electrical Engineering, Electric Power and Energy Systems.
    Gong, Yanfeng
    School of Electrical & Electronic Engineering, North China Electric Power University, Beijing 102206, China.
    Xu, Qianwen
    KTH, School of Electrical Engineering and Computer Science (EECS), Electrical Engineering, Electric Power and Energy Systems.
    Safe multi-agent deep reinforcement learning for real-time decentralized control of inverter based renewable energy resources considering communication delay2023In: Applied Energy, ISSN 0306-2619, E-ISSN 1872-9118, Vol. 349, article id 121648Article in journal (Refereed)
    Abstract [en]

    The increasing penetration of distributed renewable energy resources brings a great challenge for real-time voltage security of distribution grids. The paper proposes a safe multi-agent deep reinforcement learning (MADRL) algorithm for real-time control of inverter-based Volt-Var control (VVC) in distribution grids considering communication delay to minimize the network power loss, while maintaining the nodal voltages in a safe range. The multi-agent VVC is modeled as a constrained Markov game, which is solved by the MADRL algorithm. In the training stage, the safety projection is added to the combined policy to analytically solve an action correction formulation to promote more efficient and safe exploration. In the real-time decision-making stage, a state synchronization block is designed to impute the data under the latest timestamp as the input of the agents deployed in a distributed manner, to avoid instability caused by communication delay. The simulation results show that the proposed algorithm performs well in safe exploration, and also achieves better performance under communication delay.

  • 56. Guo, S.
    et al.
    Li, H.
    Zhao, J.
    Li, X.
    Yan, Jinyue
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Energy Processes. School of Sustainable Development of Society and Technology, Mälardalen University, SE 721 23 Västrås, Sweden .
    Numerical simulation study on optimizing charging process of the direct contact mobilized thermal energy storage2013In: Applied Energy, ISSN 0306-2619, E-ISSN 1872-9118, Vol. 112, p. 1416-1423Article in journal (Refereed)
    Abstract [en]

    Mobilized thermal energy storage (M-TES) system is considered as an attractive alternative to supply heat to distributed heat users, especially when the waste heat from industries is used as a heat source. From our previous study it was known that the charging time of M-TES system was more than four times of the discharging time, which was a critical issue for the application of M-TES. To improve the charging performance of the system and further understand the mechanism of melting process, a 2-dimensional (2D) numerical simulation model was developed in ANSYS FLUENT. The model was validated by the experimental measurements. The results showed that the model could be used for the engineering analysis. With the validated model, different options to shorten the charging time were investigated including increasing flow rate of thermal oil, creating channels before charging and adding wall heating. Correspondingly, around 25%, 26% and 29% of the charging time could be reduced respectively compared to the experiment with a thermal oil flow rate of 9.8. L/min, according to the numerical simulation. In addition, if the last two options could be applied simultaneously, more than half of the melting time might be shortened without changing the flow rate of thermal oil.

  • 57. Guo, Shaopeng
    et al.
    Zhao, Jun
    Wang, Weilong
    Yan, Jinyue
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Energy Processes.
    Jin, Guang
    Wang, Xiaotong
    Techno-economic assessment of mobilized thermal energy storage for distributed users: A case study in China2017In: Applied Energy, ISSN 0306-2619, E-ISSN 1872-9118, Vol. 194, p. 481-486Article in journal (Refereed)
    Abstract [en]

    The mobilized thermal energy storage (M-TES) system is a promising alternative to conventional heating systems to meet the heat demand for distributed users. This paper provided a techno-economic assessment of the M-TES system based on a case study in China. According to the analysis of the design specifications of the heating system, the suitability of matching the M-TES with existing heating systems was analyzed. The results show that the M-TES is appropriate for use with heating systems with a fan-coil unit and under-floor pipe. Containers and operating strategies for the M-TES with different transportation schemes were also designed. The maximum allowed load of the M-TES container is 39 t according to the discussion of transportation regulations on the road. The cost and income of the M-TES in the study case were estimated, and the net present value (NPV) and payback period (PBP) were also calculated. The best operating strategy is the use of 2 containers and 4 cycles of container transportation per day, with a PBP of approximately 10 years. The M-TES is applicable for middle and small-scale heat users in China.

  • 58. Guo, Shaopeng
    et al.
    Zhao, Jun
    Wang, Weilong
    Yan, Jinyue
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Energy Processes.
    Jin, Guang
    Zhang, Zhiyu
    Gu, Jie
    Niu, Yonghong
    Numerical study of the improvement of an indirect contact mobilized thermal energy storage container2016In: Applied Energy, ISSN 0306-2619, E-ISSN 1872-9118, Vol. 161, p. 476-486Article in journal (Refereed)
    Abstract [en]

    In this paper, the melting and solidification behaviours of the PCM in an indirect contact mobilized thermal energy storage (ICM-TES) container were numerically investigated to facilitate the further understanding of the phase change mechanism in the container. A 2D model was built based on the simplification and assumptions of experiments, which were validated by comparing the results of computations and measurements. Then, three options, i.e., a high thermal conductivity material (expanded graphite) addition, the tube diameter and the adjustment of the internal structure of the container and fin installation, were analyzed to seek effective approaches for the improvement of the ICM-TES performance. The results show that the optimal parameters of the three options are 10 vol.% (expanded graphite proportion), 22 mm (tube diameter) and 0.468 m(2) (fin area). When the three options are applied simultaneously, the charging time is reduced by approximately 74% and the discharging time by 67%.

  • 59.
    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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  • 60.
    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.

  • 61. 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. 

  • 62.
    Harahap, Fumi
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology.
    Leduc, Sylvain
    International Institute for Applied Systems Analysis (IIASA).
    Mesfun, Sennai
    RISE Research Institutes of Sweden.
    Khatiwada, Dilip
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology.
    Kraxner, Florian
    International Institute for Applied Systems Analysis (IIASA).
    Silveira, Semida
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology.
    Meeting the bioenergy targets from palm oil based biorefineries: An optimalconfiguration in Indonesia2020In: Applied Energy, ISSN 0306-2619, E-ISSN 1872-9118, Vol. 278, article id 115749Article in journal (Refereed)
    Abstract [en]

    Biorefineries provide opportunities to improve the economic, environmental, and social performance of bio-based production systems. Prudent planning of plant configuration and localization is however of great merit to obtain maximum benefits from biorefineries. This study investigates optimal deployment of palm oil-based biorefineries on the two major islands of Indonesia, Sumatra and Kalimantan. In addition, the results of the optimal bioenergy (bioelectricity, biodiesel, ethanol) production are used to calculate the potential contribution of the palm oil industry according to the national bioenergy targets from 2020 to 2030. This work also offers a new perspective of analyzing the role of bioenergy in the palm oil industry in relation to meeting the bioenergy targets through the development of spatially explicit optimization model, BeWhere Indonesia. Results show that the palm oil-based biorefineries in Sumatra and Kalimantan can produce 1–1.25 GW of electricity, 4.6–12.5 bL of biodiesel, and 2.8–4.8 bL of ethanol in 2030. Significant efforts in terms of mobilization of resources and economic instruments are required to harness the full potential offered by the palm oil-based biorefineries. This study provides an important insight on how palm oil biorefineries can be developed for their enhanced roles in meeting global sustainability efforts.

  • 63. 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.

  • 64.
    Herre, Lars
    et al.
    KTH, School of Electrical Engineering and Computer Science (EECS), Electrical Engineering, Electric Power and Energy Systems.
    Tomasini, Federica
    KTH, School of Electrical Engineering and Computer Science (EECS), Electrical Engineering, Electric Power and Energy Systems.
    Paridari, Kaveh
    KTH, School of Electrical Engineering and Computer Science (EECS), Electrical Engineering, Electric Power and Energy Systems.
    Söder, Lennart
    KTH, School of Electrical Engineering and Computer Science (EECS), Electrical Engineering, Electric Power and Energy Systems.
    Nordström, Lars
    KTH, School of Industrial Engineering and Management (ITM), Production Engineering. KTH, School of Electrical Engineering and Computer Science (EECS), Electrical Engineering, Electric Power and Energy Systems.
    Simplified model of integrated paper mill for optimal bidding in energy and reserve markets2020In: Applied Energy, ISSN 0306-2619, E-ISSN 1872-9118, Vol. 279, article id 115857Article in journal (Refereed)
    Abstract [en]

    Due to the increased use of variable renewable energy sources, more capacity for reserves is required. Non-generating resources such as large industrial consumers can arbitrage energy prices and provide reserve capacity by exploiting the inherent flexibility in selected industrial processes. A large enough industrial consumer can capitalize on this flexibility through optimized bidding in electricity markets. In this work, the day-ahead cost minimization of a risk-averse pulp and paper mill is formulated as a two-stage stochastic problem, considering thermodynamic and electrical constraints. The bids in the energy and reserve markets are jointly optimized subject to price uncertainty as well as uncertainty of frequency realization. The results of a case study in Sweden display a significant economic benefit in exploiting the flexibility of integrated pulp and paper mills with electric boilers. The expected cost of the pulp and paper mill resulting from different strategies are compared and the risk-aversion of the pulp and paper mill is investigated. Reserve offers are mainly facilitated by fast-acting electric boilers and supported by flexibility in the steam network. We show that reserve offers can significantly improve the profitability of the pulp and paper mill.

  • 65. 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)
  • 66.
    Hu, Jing
    et al.
    Dalian Univ Technol, Sch Hydraul Engn, Dalian 116024, Peoples R China..
    Li, Yu
    Dalian Univ Technol, Sch Hydraul Engn, Dalian 116024, Peoples R China..
    Wörman, Anders
    KTH, School of Architecture and the Built Environment (ABE), Sustainable development, Environmental science and Engineering, Resources, Energy and Infrastructure.
    Zhang, Bingyao
    Dalian Univ Technol, Sch Hydraul Engn, Dalian 116024, Peoples R China..
    Ding, Wei
    Dalian Univ Technol, Sch Hydraul Engn, Dalian 116024, Peoples R China..
    Zhou, Huicheng
    Dalian Univ Technol, Sch Hydraul Engn, Dalian 116024, Peoples R China..
    Reducing energy storage demand by spatial-temporal coordination of multienergy systems2023In: Applied Energy, ISSN 0306-2619, E-ISSN 1872-9118, Vol. 329, p. 120277-, article id 120277Article in journal (Refereed)
    Abstract [en]

    Utilizing the spatial heterogeneity and climate periodicity of various available renewable energy sources can enhance the multienergy complementarity, which will further reduce the energy storage demand and contributes to the "virtual energy storage gain." In this paper, we propose a spatiotemporal coordination method based on spectral analysis for a wind-PV-hydropower system that targets the maximum virtual energy storage gain. The complementary effect of hydropower on wind and PV power can be seen as changes in the regulation ability resulting from the hydropower construction development as well as a decreased variance in the total system production output. This method is used to determine the optimal coordination distance of multiple energy sources that are matched over different periods representing typical climate variation. A case study in the Yalong River basin in China obtains the best range of hydropower bundling surrounding wind power and PV power stations under different hydropower construction planning scenarios, and it reveals that increased regulation capacity of hydropower will reduce the optimal coordination distance but can achieve more energy balance if both actual storage and virtual storage is accounted for. This approach can realize energy delivery with the optimal coordination distance to meet intensive and efficient development needs, which can provide guidance and support for the planning and construction of wind-PV-hydropower storage systems.

  • 67.
    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.

  • 68.
    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.

  • 69.
    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.

  • 70.
    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.

  • 71.
    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.

  • 72.
    Hui, Hongxun
    et al.
    Zhejiang Univ, Coll Elect Engn, Hangzhou 310027, Peoples R China..
    Ding, Yi
    Zhejiang Univ, Coll Elect Engn, Hangzhou 310027, Peoples R China..
    Shi, Qingxin
    Univ Tennessee, Dept Elect Engn & Comp Sci, Knoxville, TN 37996 USA..
    Li, Fangxing
    Univ Tennessee, Dept Elect Engn & Comp Sci, Knoxville, TN 37996 USA..
    Song, Yonghua
    Zhejiang Univ, Coll Elect Engn, Hangzhou 310027, Peoples R China.;Univ Macau, State Key Lab Internet Things Smart City, Macau 519000, Peoples R China.;Univ Macau, Dept Elect & Comp Engn, Macau 519000, Peoples R China..
    Yan, Jinyue
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemical Engineering, Energy Processes.
    5G network-based Internet of Things for demand response in smart grid: A survey on application potential2020In: Applied Energy, ISSN 0306-2619, E-ISSN 1872-9118, Vol. 257, article id UNSP 113972Article, review/survey (Refereed)
    Abstract [en]

    Demand response (DR) has been widely regarded as an effective way to provide regulation services for smart grids by controlling demand-side resources via new and improved information and communication technologies. Emerging 5G networks and 5G-based Internet of Things (IoTs) can doubtless provide better infrastructure for DR, owing to 5G's advantages of fast transfer speed, high reliability, robust security, low power consumption, and massive number of connections. However, nearly none of the existing studies have applied 5G technology to DR, which will be the subject surveyed in this paper. First, the concept of DR and recent practical advances are investigated, especially the application of communication technologies to DR. Then, a comprehensive review of the cyber security, consumer privacy, and reliability of DR is presented. These topics received little attention in the past, but they will be among the most crucial factors in the future. In addition, the essential features and typical application scenarios of 5G communication are investigated. On this basis, the advantages, methods, recent advances, and implementation planning of 5G on DR are studied. Finally, the future work that must urgently be conducted in order to achieve the application of 5G to DR is discussed. This paper's application survey of 5G on DR is carried out before 5G technology enters the large-scale commercial stage, so as to provide references and guidelines for developing future 5G networks in the smart grid paradigm.

  • 73. Jiang, Xi
    et al.
    Kraft, Markus
    Yan, Jinyue
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Energy Processes. Mälardalen University.
    Selected papers from the Twelfth International Conference on Combustion and Energy Utilisation (12th ICCEU)2015In: Applied Energy, ISSN 0306-2619, E-ISSN 1872-9118, Vol. 156, p. 747-748Article in journal (Other academic)
  • 74.
    Jin, Ming
    et al.
    Univ Calif Berkeley, Dept Ind Engn & Operat Res, Berkeley, CA 94720 USA..
    Jain, Rishee
    Stanford Univ, Dept Civil & Environm Engn, Stanford, CA 94305 USA..
    Spanos, Costas
    Univ Calif Berkeley, Dept Elect Engn & Comp Sci, Berkeley, CA 94720 USA..
    Jia, Qingshan
    Tsinghua Univ, Dept Automat, Beijing, Peoples R China..
    Norford, Leslie K.
    MIT, Dept Architecture, Cambridge, MA 02139 USA..
    Kjaergaard, Mikkel
    Univ Southern Denmark, Maersk McKinney Moller Inst, Odense, Denmark..
    Yan, Jinyue
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemical Engineering, Energy Processes. Malardalen Univ, Sch Sustainable Dev Soc & Technol, S-72123 Vasteras, Sweden.
    Energy-cyber-physical systems2019In: Applied Energy, ISSN 0306-2619, E-ISSN 1872-9118, Vol. 256, article id 113939Article in journal (Refereed)
  • 75.
    Kantarelis, Efthymios
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Energy and Furnace Technology.
    Yang, Weihong
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Energy and Furnace Technology.
    Blasiak, Wlodzimierz
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Energy and Furnace Technology.
    Forsgren, C.
    Zabaniotou, A.
    Thermochemical treatment of E-waste from small household appliances using highly pre-heated nitrogen-thermogravimetric investigation and pyrolysis kinetics2011In: Applied Energy, ISSN 0306-2619, E-ISSN 1872-9118, Vol. 88, no 3, p. 922-929Article in journal (Refereed)
    Abstract [en]

    The EU directive on waste of electrical and electronic equipment (WEEE) 2002/96/EC has set a goal of recovering 70-80% in terms of materials and energy. Nowadays, thermal cracking (pyrolysis) of such waste streams is receiving renewed attention, due to the energy and material recovery that can be achieved and therefore the sustainable waste management. However, it still lacks the kinetic background which is of great importance for a successful design of thermochemical processes. In this study the kinetic parameters of WEEE (originating from small household appliances) pyrolysis using highly pre-heated nitrogen under six different heating rates (1-2.5 K/s) have been estimated using a combination of model-free and model fitted methods. Even though WEEE is heterogeneous material, similar behavior at each of the six different heating rates applied was observed. The activation energy of the pyrolysis process determined with two different model-free methods gave comparable results. Pre-exponential factor and reaction order were determined using the Coats-Redfern method. The estimated kinetic parameters for the WEEE pyrolysis are: E = 95.54 kJ/mol, A = 1.06 x 10(8) and n = 3.38.

  • 76.
    Karakaya, Emrah
    KTH, School of Industrial Engineering and Management (ITM), Industrial Economics and Management (Dept.), Sustainability and Industrial Dynamics. Universidad Politecnica de Madrid, Spain.
    Finite Element Method for Forecasting the Diffusion of Photovoltaic Systems: Why and How?2016In: Applied Energy, ISSN 0306-2619, E-ISSN 1872-9118, Vol. 163, p. 464-475Article in journal (Refereed)
    Abstract [en]

    The Finite Element Method (FEM) has been used in the broad field of continuum mechanics in engineering disciplines for several decades. However, recently, some scholars have attempted to apply the method to social science phenomena. What is the scope of using FEM in social science-related fields?  Anchored in the literature on social sciences, this paper, firstly, reviews the scope of using FEM in social science phenomena, and then applies FEM to a semi-hypothetical case study on the diffusion of solar photovoltaic systems in southern Germany.  By doing so, the paper aims to shed light on why and how the Finite Element Method can be used to forecast the diffusion of solar photovoltaic systems in time and space. Unlike conventional models used in diffusion literature, the computational model considers spatial heterogeneity. The model is based on a partial differential equation that describes the diffusion ratio of photovoltaic systems in a given region over time. The results of the application show that the FEM constitutes a powerful tool by which to study the diffusion of an innovation as a simultaneous space-time process.

  • 77.
    Khatiwada, Dilip
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Energy and Climate Studies, ECS.
    Venkata K., Bharadwaj
    World Bioenergy Association, Holländargatan 17, 111 60 Stockholm, Sweden.
    Silveira, Semida
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Energy and Climate Studies, ECS.
    Johnson X., Francis
    Stockholm Environment Institute (SEI) Africa Centre, c/o ICRAF, United Nations Avenue, 00100 Nairobi, Kenya.
    Energy and GHG balances of ethanol production from cane molasses in Indonesia2016In: Applied Energy, ISSN 0306-2619, E-ISSN 1872-9118, Vol. 164, p. 756-768Article in journal (Refereed)
    Abstract [en]

    This study analyses the sustainability of fuel ethanol production from cane molasses in Indonesia. Life cycle assessment (LCA) is performed to evaluate the net emissions (climate change impact) and energy inputs (resource consumption) in the production chain. The lifecycle greenhouse gas (GHG) emissions in the production and use of ethanol are estimated at 29 gCO2eq per MJ of ethanol produced which is a 67% reduction in comparison to gasoline emissions. Net Energy Value (NEV) and Net Renewable Energy Value (NREV) are -7 MJ/l and 17.7 MJ/l, while the energy yield ratio (ER) is 6.1. Economic allocation is chosen for dividing environmental burdens and resource consumption between sugar (i.e. main product) and molasses (i.e. co-product used for fuel production). Sensitivity analysis of various parameters is performed. The emissions and energy values are highly sensitive to sugarcane yield, ethanol yield, and the price of molasses. The use of sugarcane biomass residues (bagasse/trash) for efficient cogeneration, and different waste management options for the treatment of spent wash (effluent of distilleries) are also explored. Surplus bioelectricity generation in the efficient cogeneration plant, biogas recovery from wastewater treatment plant, and their use for fossil fuel substitution can help improve energy and environmental gains. The study also compares important results with other relevant international studies and discusses issues related to land use change (LUC) impact.

  • 78.
    Khodabakhshian, Mohammad
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Machine Design (Dept.), Mechatronics.
    Feng, Lei
    KTH, School of Industrial Engineering and Management (ITM), Machine Design (Dept.), Mechatronics.
    Börjesson, Stefan
    Lindgärde, Olof
    Wikander, Jan
    KTH, School of Industrial Engineering and Management (ITM), Machine Design (Dept.), Mechatronics.
    Reducing Auxiliary Energy Consumption of Heavy Trucks by Onboard Prediction and Real-time Optimization2017In: Applied Energy, ISSN 0306-2619, E-ISSN 1872-9118, Vol. 188, p. 652-671Article in journal (Refereed)
    Abstract [en]

    The electric engine cooling system, where the coolant pump and the radiator fan are driven by electric motors, admits advanced control methods to decrease auxiliary energy consumption. Recent publications show the fuel saving potential of optimal control strategies for the electric cooling system through offline simulations. These strategies often assume full knowledge of the drive cycle and compute the optimal control sequence by expensive global optimization methods. In reality, the full drive cycle is unknown during driving and global optimization not directly applicable on resource-constrained truck electronic control units. This paper reports state-of-the-art engineering achievements of exploiting vehicular onboard prediction for a limited time horizon and minimizing the auxiliary energy consumption of the electric cooling system through real-time optimization. The prediction and optimization are integrated into a model predictive controller (MPC), which is implemented on a dSPACE MicroAutoBox and tested on a truck on a public road. Systematic simulations show that the new method reduces fuel consumption of a 40-tonne truck by 0.36% and a 60-tonne truck by 0.69% in a real drive cycle compared to a base-line controller. The reductions on auxiliary fuel consumption for the 40-tonne and 60-tonne trucks are about 26% and 38%, respectively. Truck experiments validate the consistency between simulations and experiments and confirm the real-time feasibility of the MPC controller. 

  • 79.
    Killer, Marvin
    et al.
    KTH, School of Electrical Engineering and Computer Science (EECS).
    Farrokhseresht, M.
    Paterakis, N. G.
    Implementation of large-scale Li-ion battery energy storage systems within the EMEA region2020In: Applied Energy, ISSN 0306-2619, E-ISSN 1872-9118, Vol. 260, article id 114166Article in journal (Refereed)
    Abstract [en]

    Large-scale Lithium-ion Battery Energy Storage Systems (BESS) are gradually playing a very relevant role within electric networks in Europe, the Middle East and Africa (EMEA). The high energy density of Li-ion based batteries in combination with a remarkable round-trip efficiency and constant decrease in the levelized cost of storage have led to the recent boom of the technology. However, many of the potential applications of large-scale battery systems are not economically viable at this point in time. As a result, several BESS projects are being pushed by the industry towards specific niches which are based on revenue streams that can be rather complex than straightforward. The aim of this paper is to provide an overview of how large-scale Li-ion BESS are currently being implemented in the EMEA region, giving an answer to the following questions: what are the main use-cases of large-scale Li-ion batteries that are being implemented? What are the key factors that are enabling the deployment of BESS projects in the present markets? How can current tendencies be extrapolated to the future outlook of Li-ion BESS implementations? The large-scale energy storage market is evolving at a very fast pace, hence this review paper intends to contribute to a better understanding of the current status of Li-ion battery systems focusing on the economic feasibility that is driving the realization of Li-ion BESS projects in the EMEA region.

  • 80.
    Kordas, Olga
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Sustainable development, Environmental science and Engineering.
    Liu, Gengyuan
    Ulgiati, Sergio
    Energy and urban systems2017In: Applied Energy, ISSN 0306-2619, E-ISSN 1872-9118, Vol. 186, p. 83-85Article in journal (Other academic)
  • 81.
    Koziel, Sylvie Evelyne
    et al.
    KTH, School of Electrical Engineering and Computer Science (EECS), Electrical Engineering, Electromagnetic Engineering.
    Hilber, Patrik
    KTH, School of Electrical Engineering and Computer Science (EECS), Electrical Engineering, Electromagnetic Engineering.
    Westerlund, Per
    KTH, School of Electrical Engineering and Computer Science (EECS), Electrical Engineering.
    Shayesteh, Ebrahim
    Vattenfall Serv Nordic AB, Evenemangsgatan 13C, S-16956 Solna, Sweden..
    Investments in data quality: Evaluating impacts of faulty data on asset management in power systems2021In: Applied Energy, ISSN 0306-2619, E-ISSN 1872-9118, Vol. 281, article id 116057Article in journal (Refereed)
    Abstract [en]

    Data play an essential role in asset management decisions. The amount of data is increasing through accumu-lating historical data records, new measuring devices, and communication technology, notably with the evolution toward smart grids. Consequently, the management of data quantity and quality is becoming even more relevant for asset managers to meet efficiency and reliability requirements for power grids. In this work, we propose an innovative data quality management framework enabling asset managers (i) to quantify the impact of poor data quality, and (ii) to determine the conditions under which an investment in data quality improvement is required. To this end, an algorithm is used to determine the optimal year for component replacement based on three scenarios, a Reference scenario, an Imperfect information scenario, and an Investment in higher data quality scenario. Our results indicate that (i) the impact on the optimal year of replacement is the highest for middleaged components; (ii) the profitability of investments in data quality improvement depends on various factors, including data quality, and the cost of investment in data quality improvement. Finally, we discuss the implementation of the proposed models to control data quality in practice, while taking into account real-world technological and economic limitations.

  • 82. Kupecki, J.
    et al.
    Papurello, D.
    Lanzini, A.
    Naumovich, Y.
    Motylinski, K.
    Blesznowski, M.
    Santarelli, M.
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology. Department of Energy (DENERG), Politecnico di Torino, Corso Duca degli Abruzzi 24, Torino 10129, Italy.
    Numerical model of planar anode supported solid oxide fuel cell fed with fuel containing H2S operated in direct internal reforming mode (DIR-SOFC)2018In: Applied Energy, ISSN 0306-2619, E-ISSN 1872-9118, Vol. 230, p. 1573-1584Article in journal (Refereed)
    Abstract [en]

    Experimental analysis of a planar 100 mm × 100 mm SOFC cell was conducted during operation at 1173 K in direct internal reforming (DIR) mode. In the first phase the rate of direct internal reforming was varied from 0 to 100% what corresponds to complete external reforming and complete DIR, respectively. In the second phase 1.2 ppm(v) of H2S was introduced to the feeding gas and the variation of the rate of direct internal reforming was repeated. Following the experimental analysis the numerical model was proposed to determine the correlation between the presence of the poisoning agent and the electrochemical performance. The effect on the resistance of the cell was studied. The lumped volume model was applied to predict the cell voltage. With the use of the experimental data it was possible to determine the relative change of the model parameters which describe the ionic and electronic conductivity of the SOFC. Model was adopted for predictive modeling of the solid oxide fuel cell, operated in DIR-SOFC mode with and without the presence of hydrogen sulfide. Additionally, literature data measured for a cell operated in complete internal reforming mode with variation of the sulfur content in the feeding gas were analyzed to define the effect of H2S content on the performance drop. Relative change of the resistance of a cell was correlated with the rate of internal reforming and the content of sulfur. Results of the analysis show that the degradation of the performance of SOFC due to sulfur poisoning during operation in DIR mode can be modelled with high fidelity. Change of the ionic and electronic resistance of a cell accounted for the maximum of 34 and 53%, respectively when the rate of DIR was altered between 0 and 100%. The contribution of the sulfur poisoning accounts for 69 and 79% when the H2S content varies in the range of 0.001–5 ppm(v). With average relative prediction error below 3%, the proposed approach finds good application in simulating the performance of a cell exposed to different gas mixtures with different levels of sulfur in the fuel stream. 

  • 83. Lam, Hon Loong
    et al.
    Varbanov, Petar Sabev
    Klemes, Jiri Jaromir
    Yan, Jinyue
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Energy Processes.
    Green Applied Energy for sustainable development2016In: Applied Energy, ISSN 0306-2619, E-ISSN 1872-9118, Vol. 161, p. 601-604Article in journal (Other academic)
    Abstract [en]

    This special issue of Applied Energy contains articles developed from initial ideas related to the 17th Conference Process Integration, Modelling and Optimisation for Energy Saving and Pollution Reduction (PRES 2014) held in Prague, Czech Republic, during 23-27 August 2014. The conference has been organised jointly with CHISA 2014. Both events have benefitted from the shared pool of participants as well as the expanded opportunities for exchanging ideas. From all contributions presented at the conference, high-quality ones suitable for Applied Energy, have been invited. Overall, 37 extended manuscripts have been invited as candidate articles. Of those, after a thorough review procedure, 11 articles have been selected to be published. The topics attained in the focus of this Special Issue include Process Integration and Energy Management, CO2 capture, and Green Energy Applications.

  • 84.
    Larsson, Magnus
    et al.
    KTH.
    Yan, Jinying
    KTH. Vattenfall AB, Sweden.
    Nordenskjöld, C.
    Forsberg, Kerstin
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Chemical Engineering.
    Liu, Longcheng
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Chemical Engineering.
    Characterisation of stormwater in biomass-fired combined heat and power plants: Impact of biomass fuel storage2016In: Applied Energy, ISSN 0306-2619, E-ISSN 1872-9118, Vol. 170, p. 116-129Article in journal (Refereed)
    Abstract [en]

    Characteristics of stormwater in industrial areas are evaluated, specifically based on a biomass-fired combined heat and power (CHP) plant with on-site biomass fuel storage. An evaluation method is developed to combine general methodology applied for stormwater characterisation with the on-site features of the biomass-fired CHP plant. Investigations were carried out through on-site monitoring and laboratory experiments with the defined methodology. Recycled wood chips as biomass fuel currently used in Swedish biomass-fired CHP plants have been used as an example for this study. The impacts of outdoor biomass fuel storage have been analysed for both runoff water quantity and quality. The results indicate that the properties of stored biomass fuels will significantly affect the runoff quantity by its water absorption capability. The overall runoff quality is highly depended on precipitation intensity and the runoff volume from the biomass storage piles, which is influenced by the water retention capacity and leaching ability of biomass fuels. The practical data and information presented in this paper can be used to understand the principal issues and the most important factors for internal control of contamination sources in order to achieve sustainable Energy-Water systems for bioenergy conversion in biomass-fired CHP plants.

  • 85. Lee, Mengshan
    et al.
    Keller, Arturo A.
    Chiang, Pen-Chi
    Den, Walter
    Wang, Hongtao
    Hou, Chia-Hung
    Wu, Jiang
    Wang, Xin
    Yan, Jinyue
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemical Engineering, Energy Processes.
    Water-energy nexus for urban water systems: A comparative review on energy intensity and environmental impacts in relation to global water risks2017In: Applied Energy, ISSN 0306-2619, E-ISSN 1872-9118, Vol. 205, p. 589-601Article in journal (Refereed)
    Abstract [en]

    The importance of the interdependence between water and energy, also known as the water-energy nexus, is well recognized. The water-energy nexus is typically characterized in resource use efficiency terms such as energy intensity. This study aims to explore the quantitative results of the nexus in terms of energy intensity and environmental impacts (mainly greenhouse gas emissions) on existing water systems within urban water cycles. We also characterized the influence of water risks on the water-energy nexus, including baseline water stress (a water quantity indicator) and return flow ratio (a water quality indicator). For the 20 regions and 4 countries surveyed (including regions with low to extremely high water risks that are geographically located in Africa, Australia, Asia, Europe, and North America), their energy intensities were positively related to the water risks. Regions with higher water risks were observed to have relatively higher energy and GHG intensities associated with their water supply systems. This mainly reflected the major influence of source water accessibility on the nexus, particularly for regions requiring energy-intensive imported or groundwater supplies, or desalination. Regions that use tertiary treatment (for water reclamation or environmental protection) for their wastewater treatment systems also had relatively higher energy and GHG emission intensities, but the intensities seemed to be independent from the water risks. On-site energy recovery (e.g., biogas or waste heat) in the wastewater treatment systems offered a great opportunity for reducing overall energy demand and its associated environmental impacts. Future policy making for the water and energy sectors should carefully consider the water energy nexus at the regional or local level to achieve maximum environmental and economic benefits. The results from this study can provide a better understanding of the water-energy nexus and informative recommendations for future policy directions for the effective management of water and energy.

  • 86.
    Leung, Dennis Y. C.
    et al.
    Univ Hong Kong, Hong Kong, Hong Kong, Peoples R China..
    Yang, Hongxing
    Hong Kong Polytech Univ, Hong Kong, Hong Kong, Peoples R China..
    Yan, Jinyue
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemical Engineering, Energy Processes.
    Editorial for Special Issue of the First International Conference on Applied Energy, ICAE'09, Hong Kong, January 5-7, 2009 at the journal, Applied Energy2010In: Applied Energy, ISSN 0306-2619, E-ISSN 1872-9118, Vol. 87, no 9, p. 2861-2861Article in journal (Other academic)
  • 87. Li, A.
    et al.
    Song, Ce
    KTH, School of Biotechnology (BIO), Theoretical Chemistry and Biology. University of Science and Technology of China, China.
    Lin, Z.
    A multiphysics fully coupled modeling tool for the design and operation analysis of planar solid oxide fuel cell stacks2017In: Applied Energy, ISSN 0306-2619, E-ISSN 1872-9118, Vol. 190, p. 1234-1244Article in journal (Refereed)
    Abstract [en]

    A planar SOFC stack is an integral but basic power generation unit with physical conditions completely different from that of a laboratory button cell. The ability to reliably predict the operating behaviors of SOFC stacks is crucial for the technology advancement. The existing stack models either rely on simplified geometries, or handle a few selected fields that are relatively easy to couple. This paper reports the first successful development of a high geometry resolution, multiphysics fully coupled numerical model for production scale planar SOFC stacks. The computational model is developed through in-house developed multiphysics modules combined with commercial software FLUENT®. All stack components such as flow channels, manifolds, cathode-electrolyte-anode assemblies, interconnects, seals and frames are resolved in the numerical grids. The mathematical model includes the fully coupled equations of momentum, mass, species, heat and charge transports, electrochemical reaction, and methane steam reforming and shift reactions. An accurate relationship between the O2 transport and electrochemistry within the cathode-rib structure is established and used to enhance the numerical efficiency of the stack model. The stack model is validated with the experimental data. The numerical stability and modeling capability of this multiphysics stack model are illustrated by simulating a 30-cell stack of 27 million grid points. Detailed information about the distributions of flows, temperature, current and chemical species, etc, is revealed. Comparative studies show that the results obtained by simplifications of stack geometries or reductions of multiphysics couplings are unreliable, illustrating the necessity of employing a true multiphysics computational tool.

  • 88. Li, Changzhu
    et al.
    Liu, Dehua
    Ramaswamy,
    Yan, Jinyue
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Energy Processes. Mälardalen University, Sweden.
    Biomass energy and products: Advanced technologies and applications2015In: Applied Energy, ISSN 0306-2619, E-ISSN 1872-9118, Vol. 157, p. 489-490Article in journal (Other academic)
  • 89. Li, H.
    et al.
    Campana, Pietro Elia
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemical Engineering, Energy Processes.
    Tan, Yuting
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemical Engineering.
    Yan, Jerry
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemical Engineering, Energy Processes.
    Feasibility study about using a stand-alone wind power driven heat pump for space heating2018In: Applied Energy, ISSN 0306-2619, E-ISSN 1872-9118, Vol. 228, p. 1486-1498Article in journal (Refereed)
    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. 

  • 90. Li, H.
    et al.
    Wang, W.
    Yan, Jinyue
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Energy Processes.
    Dahlquist, E.
    Economic assessment of the mobilized thermal energy storage (M-TES) system for distributed heat supply2013In: Applied Energy, ISSN 0306-2619, E-ISSN 1872-9118, Vol. 104, p. 178-186Article in journal (Refereed)
    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.

  • 91. Li, Hailong
    et al.
    Ditaranto, Mario
    Yan, Jinyue
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Energy Processes.
    Carbon capture with low energy penalty: Supplementary fired natural gas combined cycles2012In: Applied Energy, ISSN 0306-2619, E-ISSN 1872-9118, Vol. 97, p. 164-169Article in journal (Refereed)
    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.

  • 92.
    Li, Hailong
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Energy Processes.
    Jakobsen, Jana P.
    Wilhelmsen, Oivind
    Yan, Jinyue
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Energy Processes.
    PVTxy properties of CO(2) mixtures relevant for CO(2) capture, transport and storage: Review of available experimental data and theoretical models2011In: Applied Energy, ISSN 0306-2619, E-ISSN 1872-9118, Vol. 88, no 11, p. 3567-3579Article in journal (Refereed)
    Abstract [en]

    The knowledge about pressure-volume-temperature-composition (PVTxy) properties plays an important role in the design and operation of many processes involved in CO(2) capture and storage (CCS) systems. A literature survey was conducted on both the available experimental data and the theoretical models associated with the thermodynamic properties of CO(2) mixtures within the operation window of CCS. Some gaps were identified between available experimental data and requirements of the system design and operation. The major concerns are: for the vapour-liquid equilibrium, there are no data about CO(2)/COS and few data about the CO(2)/N(2)O(4) mixture. For the volume property, there are no published experimental data for CO(2)/O(2), CO(2)/CO, CO(2)/N(2)O(4), CO(2)/COS and CO(2)/NH(3) and the liquid volume of CO(2)/H(2). The experimental data available for multi-component CO(2) mixtures are also scarce. Many equations of state are available for thermodynamic calculations of CO(2) mixtures. The cubic equations of state have the simplest structure and are capable of giving reasonable results for the PVTxy properties. More complex equations of state such as Lee-Kesler, SAFT and GERG typically give better results for the volume property, but not necessarily for the vapour-liquid equilibrium. None of the equations of state evaluated in 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.

  • 93. Li, Hailong
    et al.
    Jakobsen, Jana P.
    Wilhelmsen, Øivind
    Yan, Jinyue
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Energy Processes.
    Responses to 'Comments on PVTxy properties of CO2 mixtures relevant for CO2 capture, transport and storage: Review of available experimental data and theoretical models'2012In: Applied Energy, ISSN 0306-2619, E-ISSN 1872-9118, Vol. 93, p. 753-754Article in journal (Other academic)
  • 94.
    Li, Hailong
    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.
    Evaluating cubic equations of state for calculation of vapor-liquid equilibrium of CO2 and CO2-mixtures for CO2 capture and storage processes2009In: Applied Energy, ISSN 0306-2619, E-ISSN 1872-9118, Vol. 86, no 6, p. 826-836Article in journal (Refereed)
    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, N-2 or O-2, 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, PIT and SRK are generally superior to RK and 3P1T. The impacts of binary interaction parameter k(ij) were also analyzed. k(ij) 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.

  • 95.
    Li, Hailong
    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.
    Impacts of equations of state (EOS) and impurities on the volume calculation of CO2 mixtures in the applications of CO2 capture and storage (CCS) processes2009In: Applied Energy, ISSN 0306-2619, E-ISSN 1872-9118, Vol. 86, no 12, p. 2760-2770Article in journal (Refereed)
    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, At and N-2, 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, k(ij) was calibrated for all of the EOS regarding the gas and liquid phases of all the studied binary CO2 mixtures, respectively.

  • 96.
    Li, Hailong
    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.
    Yan, J.
    Vattenfall Research and Development AB.
    Anheden, M.
    Vattenfall Research and Development AB.
    Impurity impacts on the purification process in oxy-fuel combustion based CO2 capture and storage system2009In: Applied Energy, ISSN 0306-2619, E-ISSN 1872-9118, Vol. 86, no 2, p. 202-213Article in journal (Refereed)
    Abstract [en]

    Based on the requirements of CO2 transportation and storage, non-condensable gases, such as O-2, N-2 and At should be removed from the CO2-stream captured from an oxy-fuel combustion process. For a purification process, impurities have great impacts on the design, operation and optimization through their impacts on the thermodynamic properties of CO2-streams. Study results show that the increments of impurities will make the energy consumption of purification increase: and make CO2 purity of separation product and CO2 recovery rate decrease, In addition, under the same operating conditions, energy consumptions have different sensitivities to the variation of the impurity mole fraction of feed fluids. The isothermal compression work is more sensitive to the variation of SO2: while the isentropic compression work is more sensitive to the variation of Ar. In the flash system, the energy consumption of condensation in is more sensitive to the variation of Ar; but in the distillation system, the energy consumption of condensation is more sensitive to the variation of SO2, and CO2 purity of separation is more sensitive to the variation of SO2.

  • 97.
    Li, Jun
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Energy and Furnace Technology.
    Brzdekiewicz, A.
    Yang, Weihong
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Energy and Furnace Technology.
    Blasiak, Wlodzimierz
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Energy and Furnace Technology.
    Co-firing based on biomass torrefaction in a pulverized coal boiler with aim of 100% fuel switching2012In: Applied Energy, ISSN 0306-2619, E-ISSN 1872-9118, Vol. 99, p. 344-354Article in journal (Refereed)
    Abstract [en]

    Torrefied biomass has several benefits, such as higher energy density, good grindability, higher flowability and uniformity. The process of torrefaction moves the chemical and physical properties of raw biomass close to that of bituminous coal, which allows co-utilization with high substitution ratios of biomass in the existing coal-fired boilers without major modifications. In this study, a torrefaction based co-firing system was proposed and studied. Devolatilization and char oxidize kinetics of the torrefied biomass have been investigated experimentally. CFD modeling of co-firing with varying substitutions of torrefied biomass in a pulverized coal boiler have been carried out. To figure out the boiler performance when co-firing torrefied biomass, five different cases were involved and simulated, coal only, 25% biomass, 50% biomass, 75% biomass, and 100% biomass on thermal basis, respectively. The results showed torrefaction is able to provide a technical option for high substitution ratios of biomass in the co-firing system. The case-study pulverized coal boiler could be fired 100% torrefied biomass without obvious decreasing of the boiler efficiency and fluctuation of boiler load. More positively, the net CO 2 and the NO x emissions significantly reduced with increasing of biomass substitutions in the co-firing system.

  • 98.
    Lidberg, T.
    et al.
    Dalarna Univ, Sch Technol & Business Studies, SE-79188 Falun, Sweden..
    Gustafsson, Marcus
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Fluid and Climate Technology.
    Myhren, J. A.
    Dalarna Univ, Sch Technol & Business Studies, SE-79188 Falun, Sweden..
    Olofsson, T.
    Dalarna Univ, Sch Technol & Business Studies, SE-79188 Falun, Sweden.;Umeå Univ, Dept Appl Phys & Elect, SE-90187 Umeå, Sweden..
    Odlund, L.
    Linköping Univ, Dept Management & Engn, SE-58183 Linköping, Sweden..
    Environmental impact of energy refurbishment of buildings within different district heating systems2018In: Applied Energy, ISSN 0306-2619, E-ISSN 1872-9118, Vol. 227, p. 231-238Article in journal (Refereed)
    Abstract [en]

    The refurbishment of existing buildings is often considered a way to reduce energy use and CO2 emissions in the building stock. This study analyses the primary energy and CO2 impact of refurbishing a multi-family house with different refurbishment packages, given various district heating systems. Four models of typical district heating systems were defined to represent the Swedish district heating sector. The refurbishment packages were chosen to represent typical, yet innovative ways to improve the energy efficiency and indoor climate of a multi-family house. The study was made from a system perspective, including the valuation of changes in electricity use on the margin. The results show a significant difference in primary energy use for the different refurbishment packages, depending on both the package itself as well as the type of district heating system. While the packages with heat pumps had the lowest final energy use per m(2) of floor area, air heat recovery proved to reduce primary energy use and emissions of CO2-equivalents more, independent of the type of district heating system, as it leads to a smaller increase in electricity use.

  • 99.
    Lindfeldt, Erik G.
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Energy Processes.
    Saxe, Maria
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Energy Processes.
    Magnusson, Mimmi
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Energy Processes.
    Mohseni, Farzad
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Energy Processes.
    Strategies for a road transport system based on renewable resources: The case of an import-independent Sweden in 20252010In: Applied Energy, ISSN 0306-2619, E-ISSN 1872-9118, Vol. 87, no 6, p. 1836-1845Article in journal (Refereed)
    Abstract [en]

    When discussing how society can decrease greenhouse gas emissions, the transport sector is often seen as posing one of the most difficult problems. In addition, the transport sector faces problems related to security of supply. The aim of this paper is to present possible strategies for a road transport system based on renewable energy sources and to illustrate how such a system could be designed to avoid dependency on imports, using Sweden as an example. The demand-side strategies considered include measures for decreasing the demand for transport, as well as various technical and non-technical means of improving vehicle fuel economy. On the supply side, biofuels and synthetic fuels produced from renewable electricity are discussed. Calculations are performed to ascertain the possible impact of these measures on the future Swedish road transport sector. The results underline the importance of powerful demand-side measures and show that although biofuels can certainly contribute significantly to an import-independent road transport sector, they are far from enough even in a biomass-rich country like Sweden. Instead, according to this study, fuels based on renewable electricity will have to cover more than half of the road transport sector's energy demand.

  • 100. Link, Siim
    et al.
    Arvelakis, Stelios
    Paist, Aadu
    Martin, Andrew
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
    Liliedahl, Truls
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Chemical Technology.
    Sjöström, Krister
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Chemical Technology.
    Atmospheric fluidized bed gasification of untreated and leached olive residue, and co-gasification of olive residue, reed, pine pellets and Douglas fir wood chips2012In: Applied Energy, ISSN 0306-2619, E-ISSN 1872-9118, Vol. 94, p. 89-97Article in journal (Refereed)
    Abstract [en]

    The fluidized bed gasification of untreated and pre-treated olive residue and pre-treated olive residue mixed with reed, pine pellets and Douglas fir wood chips is studied. Leaching is used as a pre-treatment process targeted on the elimination of alkali metals such as K and Na as well as chlorine to reduce/eliminate the ash-related problems during gasification. The leaching pre-treatment process could affect the producer gas composition toward the lower or higher yield of CO and H-2 of the producer gas depending on the moisture content of parent fuels. The lower total tar yield of the producer gas in the case of leached olive residue was observed compared to untreated olive residue. At the same time, there are present wider varieties of different tar components in the producer gas of the leached olive residue compared to the untreated one. The distinctions in tar composition and content between the leached and untreated olive residue are attributed to the alkali and alkali earth metal and chorine chemistry affected by leaching pre-treatment. The addition of woody fuels and reed at elevated proportions resulted in the lower LHV value compared to the leached olive residue. The tar content of the producer gas is seen to increase adding reed and woody fuels to the leached olive residue, i.e. the producer gas contained additional variety of tar components whereas phenol becomes one of the key components determining the total tar content, apart from benzene, toluene and naphthalene. This is seen to be due to the higher cellulose, hemicelluloses, lignin as well as higher chlorine content of the reed and woody fuels compared to the leached olive residue. The olive residue is seen to be better fuel for gasification compared with woody fuels and reed. Even more, we believe that the leached olive residue is better compared to all other tested fuel/mixtures in this study. It is seen that the proportions of different fuels in the mixture play role in the composition of the producer gas.

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