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  • 1.
    Acuña, José
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Applied Thermodynamics and Refrigeration.
    Palm, Björn
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Applied Thermodynamics and Refrigeration.
    Distributed thermal response tests on pipe-in-pipe borehole heat exchangers2013In: Applied Energy, ISSN 0306-2619, E-ISSN 1872-9118, Vol. 109, no SI, p. 312-320Article in journal (Refereed)
    Abstract [en]

    Borehole Thermal Energy Storage systems typically use U-pipe Borehole Heat Exchangers (BHE) having borehole thermal resistances of at least 0.06 K m/W. Obviously, there is room for improvement in the U-pipe design to decrease these values. Additionally, there is a need for methods of getting more detailed knowledge about the performance of BHEs. Performing Distributed Thermal Response Tests (DTRT) on new proposed designs helps to fill this gap, as the ground thermal conductivity and thermal resistances in a BHE can be determined at many instances in the borehole thanks to distributed temperature measurements along the depth. In this paper, results from three heat injection DTRTs carried out on two coaxial pipe-in-pipe BHEs at different flow rates are presented for the first time. The tested pipe-in-pipe geometry consists of a central tube inserted into a larger external flexible pipe, forming an annular space between them. The external pipe is pressed to the borehole wall by applying a slight overpressure at the inside, resulting in good thermal contact and at the same time opening up for a novel method for measuring the borehole wall temperature in situ, by squeezing a fiber optic cable between the external pipe and the borehole wall. A reflection about how to calculate borehole thermal resistance in pipe-in-pipe BHEs is presented. Detailed fluid and borehole wall temperatures along the depth during the whole duration of the DTRTs allowed to calculate local and effective borehole thermal resistances and ground thermal conductivities. Local thermal resistances were found to be almost negligible as compared to U-pipe BHEs, and the effective borehole resistance equal to about 0.03 K m/W. The injected power was found to be almost evenly distributed along the depth.

  • 2.
    Araoz Ramos, Joseph A.
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology. Facultad de Ciencias y Tecnología (FCyT), Universidad Mayor de San Simon (UMSS), Cochabamba, Bolivia.
    Salomon, Marianne
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
    Alejo, Lucio
    Fransson, Torsten H.
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
    Numerical simulation for the design analysis of kinematic Stirling engines2015In: Applied Energy, ISSN 0306-2619, E-ISSN 1872-9118, Vol. 159, p. 633-650Article in journal (Refereed)
    Abstract [en]

    The Stirling engine is a closed-cycle regenerative system that presents good theoretical properties. These include a high thermodynamic efficiency, low emissions levels thanks to a controlled external heat source, and multi-fuel capability among others. However, the performance of actual prototypes largely differs from the mentioned theoretical potential. Actual engine prototypes present low electrical power outputs and high energy losses. These are mainly attributed to the complex interaction between the different components of the engine, and the challenging heat transfer and fluid dynamics requirements. Furthermore, the integration of the engine into decentralized energy systems such as the Combined Heat and Power systems (CHP) entails additional complications. These has increased the need for engineering tools that could assess design improvements, considering a broader range of parameters that would influence the engine performance when integrated within overall systems. Following this trend, the current work aimed to implement an analysis that could integrate the thermodynamics, and the thermal and mechanical interactions that influence the performance of kinematic Stirling engines. In particular for their use in Combined Heat and Power systems. The mentioned analysis was applied for the study of an engine prototype that presented very low experimental performance. The numerical methodology was selected for the identification of possible causes that limited the performance. This analysis is based on a second order Stirling engine model that was previously developed and validated. The simulation allowed to evaluate the effect that different design and operational parameters have on the engine performance, and consequently different performance curves were obtained. These curves allowed to identify ranges for the charged pressure, temperature ratio, heat exchangers dimensions, crank phase angle and crank mechanical effectiveness, where the engine performance was improved. In addition, the curves also permitted to recognise ranges were the design parameters could drastically reduce the brake power and efficiency. The results also showed that the design of the engine is affected by the conditions imposed by the CHP interactions, and that the engine could reach a brake power closer to 832 W with a corresponding brake efficiency of 26% when the adequate design parameters were considered. On the other hand, the performance could also be very low; as the reported in experimental tests, with brake power measurements ranging 52-120W.

  • 3.
    Armendariz, Mikel
    et al.
    KTH, School of Electrical Engineering (EES), Electric Power and Energy Systems.
    Heleno, Miguel
    Lawrence Berkeley National Laboratory.
    Cardoso, Gonçalo
    Lawrence Berkeley National Laboratory.
    Mashayekh, Salman
    Lawrence Berkeley National Laboratory.
    Stadler, Michael
    Lawrence Berkeley National Laboratory.
    Nordström, Lars
    KTH, School of Electrical Engineering (EES), Electric Power and Energy Systems.
    Coordinated Microgrid Investment and Planning Process Considering the System Operator2017In: Applied Energy, ISSN 0306-2619, E-ISSN 1872-9118, Vol. 200, p. 132-140Article in journal (Refereed)
    Abstract [en]

    Nowadays, a significant number of distribution systems are facing problems to accommodate more photovoltaic (PV) capacity, namely due to the overvoltages during the daylight periods. This has an impact on the private investments in distributed energy resources (DER), since it occurs exactly when the PV prices are becoming attractive, and the opportunity to an energy transition based on solar technologies is being wasted. In particular, this limitation of the networks is a barrier for larger consumers, such as commercial and public buildings, aiming at investing in PV capacity and start operating as microgrids connected to the MV network. To address this challenge, this paper presents a coordinated approach to the microgrid investment and planning problem, where the system operator and the microgrid owner collaborate to improve the voltage control capabilities of the distribution network, increasing the PV potential. The results prove that this collaboration has the benefit of increasing the value of the microgrid investments while improving the quality of service of the system and it should be considered in the future regulatory framework.

  • 4. Bartusch, C.
    et al.
    Alvehag, Karin
    KTH, School of Electrical Engineering (EES), Electric Power Systems.
    Further exploring the potential of residential demand response programs in electricity distribution2014In: Applied Energy, ISSN 0306-2619, E-ISSN 1872-9118, Vol. 125, p. 39-59Article in journal (Refereed)
    Abstract [en]

    Smart grids play a key role in realizing climate ambitions. Boosting consumption flexibility is an essential measure in bringing the potential gains of smart grids to fruition. The collective scientific understanding of demand response programs argues that time-of-use tariffs have proven its merits. The findings upon which this conclusion rests are, however, primarily derived from studies covering energy-based time-of-use rates over fairly short periods of time. Hence, this empirical study set out with the intention of estimating the extent of response to a demand-based time-of-use electricity distribution tariff among Swedish single-family homes in the long term. The results show that six years after the implementation households still respond to the price signals of the tariff by cutting demand in peak hours and shifting electricity consumption from peak to off-peak hours. Studies conducted in the Nordic countries commonly include only homeowners and so another aim of the study was to explore the potential of demand response programs among households living in apartment buildings. The demand-based tariff proved to bring about similar, but not as marked, effects in rental apartments, whereas there are virtually no corresponding evidences of demand response in condominium apartments.

  • 5. Beier, R. A.
    et al.
    Acuña, José
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Applied Thermodynamics and Refrigeration.
    Mogensen, P.
    Palm, Björn
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Applied Thermodynamics and Refrigeration.
    Borehole resistance and vertical temperature profiles in coaxial borehole heat exchangers2013In: Applied Energy, ISSN 0306-2619, E-ISSN 1872-9118, Vol. 102, p. 665-675Article in journal (Refereed)
    Abstract [en]

    Ground source heat pump systems are often coupled to the ground by circulating a fluid through vertical Borehole Heat Exchangers (BHEs). The design of a system requires estimates of the ground thermal conductivity and the borehole thermal resistance, which are usually determined by an in situ thermal response test on a completed borehole. The usual test interpretation methods average the inlet and outlet fluid temperatures and use this mean temperature as the average temperature along the borehole length. This assumption is convenient but does not strictly apply. For a coaxial heat exchanger this paper develops an analytical model for the vertical temperature profiles, which can be used instead of the mean temperature approximation to estimate borehole resistance. The model is verified with measured temperatures on a BHE, where an optical technique allows continuous measurements along a coaxial borehole during a distributed thermal response test. A sensitivity study shows that the proposed method corrects errors in the mean temperature approximation, which overestimates the borehole resistance in a coaxial borehole.

  • 6.
    Bekele, Getachew
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Applied Thermodynamics and Refrigeration.
    Palm, Björn
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Applied Thermodynamics and Refrigeration.
    Feasibility study for a standalone solar–wind-based hybrid energy system for application in Ethiopia2010In: Applied Energy, ISSN 0306-2619, E-ISSN 1872-9118, Vol. 87, no 2, p. 487-495Article in journal (Refereed)
    Abstract [en]

    The aim of this paper is to investigate the possibility of supplying electricity from a solar-wind hybrid system to a remotely located model community detached from the main electricity grid in Ethiopia. The wind energy potential of four typical locations has been assessed in a previous article. The solar potential has also been investigated and the results are presented in detail in an accompanying article awaiting publication. For one of the sites, Addis Ababa, the results of the investigation are given here in detail. For the other sites, the results are given as sensitivity diagrams only. Based on the findings of the studies into energy potential, a feasibility study has been carried out on how to supply electricity to a model community of 200 families, which comprises 1000 people in total. The community is equipped with a community school and a health post. The electric load consists of both primary and deferrable types and comprises lighting, water pumps, radio receivers, and some clinical equipment. A software tool, Hybrid Optimization Model for Electric Renewables (HOMER) is used for the analysis. The result of the analysis is a list of feasible power supply systems, sorted according to their net present cost. Furthermore, sensitivity diagrams, showing the influence of wind speeds, PV costs, and diesel prices on the optimum solutions are also provided.

  • 7.
    Bekele, Getachew
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Applied Thermodynamics and Refrigeration.
    Palm, Björn
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Applied Thermodynamics and Refrigeration.
    Wind energy potential assessment at four typical locations in Ethiopia2009In: Applied Energy, ISSN 0306-2619, E-ISSN 1872-9118, Vol. 86, no 3, p. 388-396Article in journal (Refereed)
    Abstract [en]

    The wind energy potential at four different sites in Ethiopia - Addis Ababa (09:02N, 38:42E), Mekele (13:33N, 39:30E), Nazret (08:32N, 39:22E), and Debrezeit (8:44N, 39:02E) - has been investigated by compiling data from different sources and analyzing it using a software tool. The results relating to wind energy potential are given in terms of the monthly average wind speed, wind speed probability density function (PDF), wind speed cumulative density function (CDF), and wind speed duration curve (DC) for all four selected sites. in brief, for measurements taken at a height of 10 m, the results show that for three of the four locations the wind energy potential is reasonable, with average wind speeds of approximately 4 m/s. For the fourth site. the mean wind speed is less than 3 m/s. This study is the first stage in a longer project and will be followed by an analysis of solar energy potential and finally the design of a hybrid standalone electric energy supply system that includes a wind turbine, PV, diesel generator and battery.

  • 8.
    Binti Munajat, Nur Farizan
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
    Erlich, Catharina
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
    Fransson, Torsten H.
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
    Temperature, emission and lean blowoff limit of simulated gasified biomass in a premixed combustorIn: Applied Energy, ISSN 0306-2619, E-ISSN 1872-9118Article in journal (Other academic)
    Abstract [en]

    Biomass can be converted to a gaseous fuel through gasification in order to be used in higher efficiency conversion. Combustion of gasified biomass gas (GBG) in gas turbines, for example, potentially reduces the CO2 emission compared to natural gas and diminishes the dependence of fossil fuels. However, the wide variety in the gas composition and its lower heating value will affect the subsequent combustion process with respect to emission levels and flame stability. In this study, premixed combustion of simulated GBG is investigated experimentally at atmospheric pressure and compared with pure CH4 (simulated natural gas). Combustion performance in terms of emission levels and blowoff is observed. The GBG fuel with noncombustible to combustible components ratio of 1.5 is tested in comparison with pure CH4 at fixed input thermal load. The GBG fuel consists of a mixture of CO/H2/CH4/CO2/N2and its proportion reassembles the mixture from air‐blown gasification. The high diluent content decreases the lower heating value (LHV) and increases the volumetric flow compared to CH4. As a result, lower combustion temperature and different flame region than CH4were found in the combustor. However, the GBG combustion still can be stabilized at lower temperature and leaner condition compared to CH4 while maintaining low CO and NOx emissions. As low as ~15 ppm and ~5ppm of CO and NOxemissions, respectively, could be achieved at an equivalence ratio equal to 0.5. It was found that at a combustion temperature below ~800oC, both CO and UHC start to rise from their stable and low concentration. At different input thermal loads, a shift in the optimum operating condition for the GBG combustion was found. No auto‐ignition or flashback events were found during the combustion of GBG in all experiment conditions tested. The results show the possibility to use both GBG and natural gas in one and the same combustor without compromising low emission levels.

  • 9. Birgersson, K. E.
    et al.
    Balaya, P.
    Chou, S. K.
    Yan, Jinyue
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Energy Processes.
    Energy Solutions for a Sustainable World2012In: Applied Energy, ISSN 0306-2619, E-ISSN 1872-9118, Vol. 90, no 1, p. 1-2Article in journal (Other academic)
  • 10. Budt, M.
    et al.
    Wolf, D.
    Span, R.
    Yan, Jinyue
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Energy Processes. Mälardalen University, Sweden.
    A review on compressed air energy storage: Basic principles, past milestones and recent developments2016In: Applied Energy, ISSN 0306-2619, E-ISSN 1872-9118, Vol. 170, p. 250-268Article in journal (Refereed)
    Abstract [en]

    Over the past decades a variety of different approaches to realize Compressed Air Energy Storage (CAES) have been undertaken. This article gives an overview of present and past approaches by classifying and comparing CAES processes. This classification and comparison is substantiated by a broad historical background on how CAES has evolved over time from its very beginning until its most recent advancements. A broad review on the variety of CAES concepts and compressed air storage (CAS) options is given, evaluating their individual strengths and weaknesses. The concept of exergy is applied to CAES in order to enhance the fundamental understanding of CAES. Furthermore, the importance of accurate fluid property data for the calculation and design of CAES processes is discussed. In a final outlook upcoming R&D challenges are addressed.

  • 11.
    Bundschuh, Jochen
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Sustainable development, Environmental science and Engineering, Land and Water Resources Engineering.
    Chen, Guangnan
    Yusaf, Talal
    Chen, Shulin
    Yan, Jinyue
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Energy Processes.
    Sustainable energy and climate protection solutions in agriculture2014In: Applied Energy, ISSN 0306-2619, E-ISSN 1872-9118, Vol. 114, no SI, p. 735-736Article in journal (Refereed)
  • 12.
    Bäbler, Matthäus Ulrich
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Energy Processes.
    Phounglamcheik, Aekjuthon
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology. Luleå University of Technology, Sweden.
    Amovic, Marko
    Ljunggren, Rolf
    Engvall, Klas
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Chemical Technology.
    Modeling and pilot plant runs of slow biomass pyrolysis in a rotary kiln2017In: Applied Energy, ISSN 0306-2619, E-ISSN 1872-9118, Vol. 207, p. 123-133Article in journal (Refereed)
    Abstract [en]

    Pyrolysis of biomass in a rotary kiln finds application both as an intermediate step in multistage gasification as well as a process on its own for the production of biochar. In this work, a numerical model for pyrolysis of lignocellulosic biomass in a rotary kiln is developed. The model is based on a set of conservation equations for mass and energy, combined with independent submodels for the pyrolysis reaction, heat transfer, and granular flow inside the kiln. The pyrolysis reaction is described by a two-step mechanism where biomass decays into gas, char, and tar that subsequently undergo further reactions; the heat transfer model accounts for conduction, convection and radiation inside the kiln; and the granular flow model is described by the well known Saeman model. The model is compared to experimental data obtained from a pilot scale rotary kiln pyrolyzer. In total 9 pilot plant trials at different feed flow rate and different heat supply were run. For moderate heat supplies we found good agreement between the model and the experiments while deviations were seen at high heat supply. Using the model to simulate various operation conditions reveals a strong interplay between heat transfer and granular flow which both are controlled by the kiln rotation speed. Also, the model indicates the importance of heat losses and lays the foundation for scale up calculations and process optimization.

  • 13. Cabeza, Luisa F.
    et al.
    Martin, Viktoria
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
    Yan, Jinyue
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Energy Processes. Mälardalen University, School of Business, Västerås, Sweden .
    Advances in energy storage research and development: The 12th International Conference on Energy Storage Innostock 20122013In: Applied Energy, ISSN 0306-2619, E-ISSN 1872-9118, Vol. 109, p. 291-292Article in journal (Other academic)
  • 14. Cabeza, Luisa F.
    et al.
    Miro, Laia
    Oro, Eduard
    de Gracia, Alvaro
    Martin, Viktoria
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Applied Thermodynamics and Refrigeration.
    Kroenauer, Andreas
    Rathgeber, Christoph
    Farid, Mohammed M.
    Paksoy, Halime O.
    Martinez, Monica
    Ines Fernandez, A.
    CO2 mitigation accounting for Thermal Energy Storage (TES) case studies2015In: Applied Energy, ISSN 0306-2619, E-ISSN 1872-9118, Vol. 155, p. 365-377Article in journal (Refereed)
    Abstract [en]

    According to the IPCC, societies can respond to climate changes by adapting to its impacts and by mitigation, that is, by reducing GHG emissions. No single technology can provide all of the mitigation potential in any sector, but many technologies have been acknowledged in being able to contribute to such potential. Among the technologies that can contribute in such potential, Thermal Energy Storage (TES) is not included explicitly, but implicitly as part of technologies such as energy supply, buildings, and industry. To enable a more detailed assessment of the CO2 mitigation potential of TES across many sectors, the group Annex 25 "Surplus heat management using advanced TES for CO2 mitigation" of the Energy Conservation through Energy Storage Implementing Agreement (ECES IA) of the International Energy Agency (AEI) present in this article the CO2 mitigation potential of different case studies with integrated TES. This potential is shown using operational and embodied CO2 parameters. Results are difficult to compare since TES is always designed in relation to its application, and each technology impacts the energy system as a whole to different extents. The applications analyzed for operational CO2 are refrigeration, solar power plants, mobile heat storage in industrial waste heat recovery, passive systems in buildings, ATES for a supermarket, greenhouse applications, and dishwasher with zeolite in Germany. The paper shows that the reason for mitigation is different in each application, from energy savings to larger solar share or lowering energy consumption from appliances. The mitigation potential dues to integrated TES is quantified in kg/MW h energy produced or heat delivered. Embodied CO2 in two TES case studies is presented, buildings and solar power plants.

  • 15. Campana, P. E.
    et al.
    Leduc, S.
    Kim, M.
    Olsson, Alexander
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Energy Processes.
    Zhang, J.
    Liu, J.
    Kraxner, F.
    McCallum, I.
    Li, H.
    Yan, Jinyue
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Energy Processes. Mälardalen University, Sweden.
    Suitable and optimal locations for implementing photovoltaic water pumping systems for grassland irrigation in China2015In: Applied Energy, ISSN 0306-2619, E-ISSN 1872-9118Article in journal (Refereed)
    Abstract [en]

    Grassland plays a key role for the food security of China because of the large number of livestock raised in those areas. Thus, grassland degradation due to climate change and overgrazing is considered as one of the most severe environmental and economic threat for the future sustainable development of China. Photovoltaic water pumping systems for irrigation can play a fundamental role for the conservation of grassland areas.This paper investigates the geospatial distribution of the technically suitable grassland locations for the implementation of photovoltaic water pumping systems. The technically suitable grassland areas were taken as starting point to assess the optimal locations. The assessment of the optimal locations was conducted using a spatially explicit optimization model of renewable energy systems based on the cost minimization of the whole forage supply chain.The results indicate that the photovoltaic water pumping systems provide high potential for improving forage productivity, contributing to meet the local demand. The optimal areas are highly sensitive to several environmental and economic parameters such as increased forage potential yield, forage management costs, forage water requirements, ground water depth, forage price and CO2 price. Most of the optimal areas are selected when the market forage price ranges from 300 to 500$/tonne DM, indicating that the forage produced using PVWP technology for irrigation is already competitive compared to the imported forage.

  • 16. Campana, P. E.
    et al.
    Li, H.
    Yan, Jinyue
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Energy Processes.
    Dynamic modelling of a PV pumping system with special consideration on water demand2013In: Applied Energy, ISSN 0306-2619, E-ISSN 1872-9118, Vol. 112, no SI, p. 635-645Article in journal (Refereed)
    Abstract [en]

    The exploitation of solar energy in remote areas through photovoltaic (PV) systems is an attractive solution for water pumping for irrigation systems. The design of a photovoltaic water pumping system (PVWPS) strictly depends on the estimation of the crop water requirements and land use since the water demand varies during the watering season and the solar irradiation changes time by time. It is of significance to conduct dynamic simulations in order to achieve the successful and optimal design. The aim of this paper is to develop a dynamic modelling tool for the design of a of photovoltaic water pumping system by combining the models of the water demand, the solar PV power and the pumping system, which can be used to validate the design procedure in terms of matching between water demand and water supply. Both alternate current (AC) and direct current (DC) pumps and both fixed and two-axis tracking PV array were analyzed. The tool has been applied in a case study. Results show that it has the ability to do rapid design and optimization of PV water pumping system by reducing the power peak and selecting the proper devices from both technical and economic viewpoints. Among the different alternatives considered in this study, the AC fixed system represented the best cost effective solution.

  • 17. Campana, Pietro Elia
    et al.
    Quan, Steven Jige
    Robbio, Federico Ignacio
    Lundblad, Anders
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Energy Processes.
    Zhang, Yang
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Energy Processes.
    Ma, Tao
    Karlssona, Bjorn
    Yan, Jinyue
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology.
    Optimization of a residential district with special consideration on energy and water reliability2017In: Applied Energy, ISSN 0306-2619, E-ISSN 1872-9118, Vol. 194, p. 751-764Article in journal (Refereed)
    Abstract [en]

    Many cities around the world have reached a critical situation when it comes to energy and water supply, threatening the urban sustainable development. From an engineering and architecture perspective it is mandatory to design cities taking into account energy and water issues to achieve high living and sustainability standards. The aim of this paper is to develop an optimization model for the planning of residential urban districts with special consideration of renewables and water harvesting integration. The optimization model is multi-objective which uses a genetic algorithm to minimize the system life cycle costs, and maximize renewables and water harvesting reliability through dynamic simulations. The developed model can be used for spatial optimization design of new urban districts. It can also be employed for analyzing the performances of existing urban districts under an energy-water-economic viewpoint. The optimization results show that the reliability of the hybrid renewables based power system can vary between 40 and 95% depending on the scenarios considered regarding the built environment area and on the cases concerning the overall electric load. The levelized cost of electricity vary between 0.096 and 0.212 $/kW h. The maximum water harvesting system reliability vary between 30% and 100% depending on the built environment area distribution. For reliabilities below 20% the levelized cost of water is kept below 1 $/m(3) making competitive with the network water tariff.

  • 18. Cardoso, Andrea
    et al.
    Turhan, Ethemcan
    Philosophy and History, KTH, School of Architecture and the Built Environment (ABE), Philosophy and History of Technology, History of Science, Technology and Environment.
    Examining new geographies of coal: Dissenting energyscapes in Colombia and Turkey2018In: Applied Energy, ISSN 0306-2619, E-ISSN 1872-9118, Vol. 224, p. 398-408Article in journal (Refereed)
    Abstract [en]

    Global energy geographies are changing, call it by will or by market forces. As coal production declines or consumption is phased out in parts of the Global North, the future of coal will likely be decided in the Global South. In this article, we explore energyscapes, as multiple and nested sites of connectivity over energy, and their relation to energy justice, environmental conflicts and social movements in new geographies of coal. By putting into question the reproduction of multiple levels of socio-environmental injustices related to coal’s extraction and consumption, we trace the emerging South-South coal links with an empirical focus on Colombia and Turkey. Coal extraction and consumption, respectively, in these geographically distant but increasingly connected countries are linked by multiscalar socio-ecological interactions and conflicts. After exploring these interactions, we examine the changing energyscapes of coal operating on different layers (the market, the physical, and the socio-environmental damages) between the two countries. Our analysis reveals that these new geographies are anchored in cross-scalar environmental injustices and democratic deficits, only sustained with top-down measures and emerging bilateral dependencies. The coming challenge for energy justice, therefore, is to link local communities' claims and democratization of energyscapes between the supply and the demand sides.

  • 19.
    Chen, Feng
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering.
    Taylor, Nathaniel
    KTH, School of Electrical Engineering (EES), Electromagnetic Engineering.
    Kringos, Nicole
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Structural Engineering and Bridges.
    Electrification of Roads: Opportunities and Challenges2015In: Applied Energy, ISSN 0306-2619, E-ISSN 1872-9118, Vol. 150, p. 109-119Article in journal (Refereed)
    Abstract [en]

    The Electrical Vehicle (EV) has become a potential solution for enhancing the sustainability of our road transportation, in view of the environmental impacts traditional vehicles have regarding emissions and use of fossil fuel dependence. However, the widespread use of EVs is still restrained by the energy storage technologies, and the electrification of road transportation is still in its early stages. This paper focuses on the technical aspects related to the ‘electrification of roads’ (called ‘eRoads’) infrastructure that aims to diminish the limitations for using EVs. A historical overview of the technology development towards the electrification of road transportation is presented, along with an overview of prospective technologies for implementing an eRoad charging infrastructure. Of these, the Inductive Power Transfer (IPT) technology is examined in further details. The main objective of this paper is to explore the potential knowledge gaps that need to be filled for a successful integration of IPT technology within actual road infrastructure. As such, this paper can be used as an overview of the current state-of-the-art of eRoad infrastructure and also as guidance towards future research directions in this domain.  

  • 20.
    Chen, Jianyong
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Applied Thermodynamics and Refrigeration.
    Havtun, Hans
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Applied Thermodynamics and Refrigeration.
    Palm, Björn E.
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Applied Thermodynamics and Refrigeration.
    Conventional and advanced exergy analysis of an ejector refrigeration system2015In: Applied Energy, ISSN 0306-2619, E-ISSN 1872-9118, Vol. 144, p. 139-151Article in journal (Refereed)
    Abstract [en]

    This paper presents a comprehensive investigation of an ejector refrigeration system using conventional and advanced exergy analysis. Splitting the exergy destruction within each system component into endogenous/exogenous and avoidable/unavoidable parts provides additional useful information and improves the quality of the exergy analysis. Detailed calculations of the exergy destruction parts are schematically illustrated. Conventional exergy analysis indicates that about half of the total exergy destruction is caused by the ejector and about one quarter occurs in the generator. The advanced exergy analysis reflects the strong interactions between system components. The ejector has the highest priority to be improved, followed by the condenser and then the generator. The temperature difference in the condenser has the largest influence on the exergy destruction compared to that in the generator and the evaporator, and the ejector efficiencies are also very crucial for the exergy destruction. The system performance can be largely enhanced through improvements of the ejector and the condenser as well as the generator.

  • 21. Chiaramonti, D.
    et al.
    Lidén, G.
    Yan, Jinyue
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Energy Processes.
    Advances in sustainable biofuel production and use. The XIX international symposium on alcohol fuels2013In: Applied Energy, ISSN 0306-2619, E-ISSN 1872-9118, Vol. 102, p. 1-4Article in journal (Other academic)
  • 22. Chiaramonti, D.
    et al.
    Maniatis, K.
    Tredici, M. R.
    Verdelho, V.
    Yan, Jinyue
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Energy Processes. Malardalen Univ.
    Life Cycle Assessment of Algae Biofuels: Needs and challenges2015In: Applied Energy, ISSN 0306-2619, E-ISSN 1872-9118, Vol. 154, p. 1049-1051Article in journal (Other academic)
  • 23. Chisti, Yusuf
    et al.
    Yan, Jinyue
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Energy Processes.
    Energy from algae: Current status and future trends: Algal biofuels - A status report2011In: Applied Energy, ISSN 0306-2619, E-ISSN 1872-9118, Vol. 88, no 10, p. 3277-3279Article in journal (Other academic)
  • 24.
    Chiu, Justin NingWei
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
    Gravoille, Pauline
    National Institute of Energy, Hydraulic and Environmental Engineering, Grenoble, France.
    Martin, Viktoria
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
    Active free cooling optimization with thermal energy storage in Stockholm2013In: Applied Energy, ISSN 0306-2619, E-ISSN 1872-9118, Vol. 109, no SI, p. 523-529Article in journal (Refereed)
    Abstract [en]

    Latent heat thermal energy storage (LHTES) integrated active free cooling stores night time cold and serves as heat sink for cooling when demand rises. Passive buildings, albeit their advantages in limiting heat loss during winter time, are often paired with excessive internal overheating in summer, as shown in the first part of this study. Under the climate condition in Stockholm, LHTES systems may provide solutions for sustainable cooling with use of renewable cooling sources. This study presents a multi-objective optimization on system cost and cooling supply for various LHTES configurations followed with a sensitivity analysis on phase change material cost and energy price. Results indicate that optimized LHTES may meet cooling needs while retaining economic viability. However, LHTES based cooling systems may require substantially higher electricity demand than conventional air conditioning unit for applications where high cooling thermal power rate is to be met, a tradeoff to indoor comfort level needs to be considered to reach the concept of sustainable free cooling. We here provide a novel techno-economic feasibility study of active free cooling LHTES in Stockholm as well as new insights to cost, comfort level and energy requirement with use of multi-objective optimization algorithm.

  • 25.
    Chiu, Justin NingWei
    et al.
    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, Heat and Power Technology.
    ­Multistage Latent Heat Cold Thermal Energy Storage Design Analysis2013In: Applied Energy, ISSN 0306-2619, E-ISSN 1872-9118, Vol. 112, no SI, p. 1438-1445Article in journal (Refereed)
    Abstract [en]

    Thermal energy storage in cooling applications contributes to improvements in overall system efficiency as well as to better energy quality management. Latent heat thermal energy storage (LHTES) is used to provide load shifted thermal energy at small temperature swing with high storage density, hence an overall more compact energy system. However, the low thermal conductivity of the majority of the phase change materials (PCMs) necessitates delicate design of the active storage unit to meet power demand (high enough energy extraction/storage per amount of time).

    A performance analysis of two LHTES configurations is carried out in this work. Thermal charge and discharge rate of single PCM is compared with multistage LHTES using a cascade design of multiple PCMs at various phase change temperatures in a submerged finned pipe heat exchanger design. The work is conducted with a validated finite element based numerical simulation for evaluation of both full charge/discharge cycle and continuous half charge/discharge cycles.

    The results show that in full charge/discharge mode, the thermal performance of a multi-PCM LHTES may be improved by 10% to 40% as compared to that of a homogeneous­­ single-PCM storage unit in terms of thermal charge/discharge rate. This is due to the capability of the multistage LHTES to maintain a higher driving temperature difference for the heat transfer process in the charging and discharging processes. In half charge/discharge cycling mode, however, the thermal power rating performance of multi-PCM storage converges towards that of the single-PCM storage in melting process, reducing thus the multi-PCM enhancement. This work provides preliminary insights to multistage latent heat cold thermal energy storage design with finned pipe heat exchanger.

  • 26.
    Chiu, Justin NingWei
    et al.
    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, Heat and Power Technology.
    Submerged finned heat exchanger latent heat storage design and its experimental verification2012In: Applied Energy, ISSN 0306-2619, E-ISSN 1872-9118, Vol. 93, no SI, p. 507-516Article in journal (Refereed)
    Abstract [en]

    Thermal energy storage (TES) has shown potential in improving the overall performance in energy systems, through shifting of thermal load demand, and through matching of uneven energy availability in time and in space. Latent heat TESs demonstrate advantages over sensible heat TESs for their high storage density and small temperature swing; however, lack of accurate knowledge in novel material properties and lack in a holistic design protocol often lead to difficulties in reaching technically viable storage design. With the aim of proposing a sound latent heat based TES design-to-validation protocol, this paper covers material property characterization through Temperature-history (T-history) method, heat exchanger design through heat transfer modeling, and model validation through experimental verification. A model for submerged cylindrically finned heat exchanger latent heat storage unit with phase change material was built. The results show that performance of gelled salt-hydrate based TES can be assessed with a pure conduction based model. This material property characterization-to-model verification approach may serve as a standard in providing accurate storage design for performance evaluation.

  • 27. Choi, Byungchul
    et al.
    Park, Su Han
    Chiarmonti, David
    Bae, Hyeun-Jong
    Yan, Jinyue
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Energy Processes. Mälardalen Univ.
    Sustainable alcohol fuels promoting mobility and climate stabilization: The 21st International Symposium on Alcohol Fuels2015In: Applied Energy, ISSN 0306-2619, E-ISSN 1872-9118, Vol. 160, p. 561-565Article in journal (Other academic)
  • 28. Chua, K. J.
    et al.
    Chou, S. K.
    Yang, W. M.
    Yan, Jinyue
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Energy Processes.
    Achieving better energy-efficient air conditioning - A review of technologies and strategies2013In: Applied Energy, ISSN 0306-2619, E-ISSN 1872-9118, Vol. 104, p. 87-104Article, review/survey (Refereed)
    Abstract [en]

    Air conditioning is essential for maintaining thermal comfort in indoor environments, particularly for hot and humid climates. Today, air conditioning, comprising cooling and dehumidification, has become a necessity in commercial and residential buildings and industrial processes. It accounts for a major share of the energy consumption of a building or facility. In tropical climates, the energy consumed by heating, ventilation and air-conditioning (HVAC) can exceed 50% of the total energy consumption of a building. This significant figure is primarily due to the heavy duty placed on cooling technologies to remove both sensible and latent heat loads. Therefore, there is tremendous potential to improve the overall efficiency of the air-conditioning systems in buildings.Based on today's practical technology for cooling, the major components of a chiller plant are (1) compressors, (2) cooling towers, (3) pumps (chilled and cooling water) and (4) fans in air handling units. They all consume mainly electricity to operate. When specifying the kW/R. ton of a plant, there are two levels of monitoring cooling efficiency: (1) at the efficiency of the chiller machines or the compressors which consume a major amount of electricity; and (2) at the overall efficiency of cooling plants which include the cooling towers, pumps for moving coolant (chilled and cooling water) to all air-handling units. Pragmatically, a holistic approach is necessary towards achieving a low energy input per cooling achieved such as 0.6. kW/R. ton cooling or lower by considering all aspects of the cooling plant.In this paper, we present a review of recent innovative cooling technology and strategies that could potentially lower the kW/R. ton of cooling systems - from the existing mean of 0.9. kW/R. ton towards 0.6. kW/R. ton or lower. The paper, broadly divided into three key sections (see Fig. 2), begins with a review of the recent novel devices that enhances the energy efficiency of cooling systems at the component level. This is followed by a review of innovative cooling systems designs that reduces energy use for air conditioning. Lastly, the paper presents recent developments in intelligent air-control strategies and smart chiller sequencing methodologies that reduce the primary energy utilization for cooling.The energy efficient cooling technology, innovative systems designs, and intelligent control strategies described in the paper have been recently researched or are on-going studies. Several have been implemented on a larger scale and, therefore, are examples of practical solutions that can be readily applied to suit specific needs.

  • 29. Dahlquist, E.
    et al.
    Naqvi, M.
    Thorin, E.
    Yan, Jinyue
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Energy Processes. Mälardalen University, Sweden.
    Kyprianidis, K.
    Hartwell, P.
    Experimental and numerical investigation of pellet and black liquor gasification for polygeneration plant2017In: Applied Energy, ISSN 0306-2619, E-ISSN 1872-9118, Vol. 204, p. 1055-1064Article in journal (Refereed)
    Abstract [en]

    It is vital to perform system analysis on integrated biomass gasification in chemical recovery systems in pulp and paper and heat and power plants for polygeneration applications. The proposed integration complements existing pulp and paper and heat and power production systems with production of chemicals such as methane and hydrogen. The potential to introduce gasification-based combined cycles comprising gas turbines and steam turbines to utilize black liquors and wood pellets also merits investigation. To perform such analysis, it is important to first build knowledge on expected synthesis gas composition by gasifying at smaller scale different types of feed stock. In the present paper, the synthesis gas quality from wood pellets gasification has been compared with black liquor gasification by means of numerical simulation as well as through pilot-scale experimental investigations. The experimental results have been correlated into partial least squares models to predict the composition of the synthesis gas produced under different operating conditions. The gas quality prediction models are combined with physical models using a generic open-source modelling language for investigating the dynamic performance of large-scale integrated polygeneration plants. The analysis is further complemented by considering potential gas separation using modern membrane technology for upgrading the synthesis gas with respect to hydrogen content. The experimental data and statistical models presented in this study form an important literature source for future use by the gasification and polygeneration research community on further integrated system analysis.

  • 30. Daianova, L.
    et al.
    Dotzauer, E.
    Thorin, E.
    Yan, Jinyue
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Energy Processes.
    Evaluation of a regional bioenergy system with local production of biofuel for transportation, integrated with a CHP plant2012In: Applied Energy, ISSN 0306-2619, E-ISSN 1872-9118, Vol. 92, p. 739-749Article in journal (Refereed)
    Abstract [en]

    The share of renewable liquid fuels (ethanol, fatty acid methyl ester, biogas, and renewable electricity) in the total transportation fuel in Sweden, has increased by the end of 2009 to such level that e.g. domestic bioethanol production is unable to satisfy current ethanol fuel demand. Regional small-scale ethanol production can assist the region in covering the regional needs in transport fuel supply. Current case study system includes the production of ethanol, biogas, heat and power from locally available cereals straw. A mixed integer programming (MIP) model is developed for cost optimization of regional transport fuel supply (ethanol, biogas and petrol). The model is applied for two cases, one when ethanol production plant is integrated with an existing CHP plant (polygeneration), and one with a standalone ethanol production plant. The optimization results show that for both cases the changes in ethanol production costs have the biggest influence on the costs for supplying regional passenger car fleet with transport fuel. Petrol fuel price and straw production costs have also a significant effect on costs for supplying cars with transport fuel for both standalone ethanol production and integrated production system. By integrating the ethanol production process with a CHP plant, the costs for supplying regional passenger car fleet with transport fuel can be cut by 31%, from 150 to 104 (sic)/MW h fuel, which should be compared with E5 costs of 115 E/MW h (excl VAT).

  • 31. Desideri, U.
    et al.
    Yan, Jinyue
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology.
    Clean energy technologies and systems for a sustainable world2012In: Applied Energy, ISSN 0306-2619, E-ISSN 1872-9118, Vol. 97, p. 1-4Article in journal (Other academic)
  • 32.
    Ding, Jing
    et al.
    Sun Yat Sen Univ, Sch Engn, Guangzhou 510006, Guangdong, Peoples R China..
    Du, Lichan
    Sun Yat Sen Univ, Sch Engn, Guangzhou 510006, Guangdong, Peoples R China..
    Pan, Gechuanqi
    Sun Yat Sen Univ, Sch Engn, Guangzhou 510006, Guangdong, Peoples R China..
    Lu, Jianfeng
    Sun Yat Sen Univ, Sch Engn, Guangzhou 510006, Guangdong, Peoples R China..
    Wei, Xiaolan
    South China Univ Technol, Sch Chem & Chem Engn, Guangzhou 510640, Guangdong, Peoples R China..
    Li, Jiang
    Natl Supercomp Ctr Guangzhou, Guangzhou 510006, Guangdong, Peoples R China..
    Wang, Weilong
    Sun Yat Sen Univ, Sch Engn, Guangzhou 510006, Guangdong, Peoples R China..
    Yan, Jinyue
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemical Engineering, Energy Processes. Malardalen Univ, Sch Business Soc & Energy, Vasteras, Sweden.
    Molecular dynamics simulations of the local structures and thermodynamic properties on molten alkali carbonate K2CO32018In: Applied Energy, ISSN 0306-2619, E-ISSN 1872-9118, Vol. 220, p. 536-544Article in journal (Refereed)
    Abstract [en]

    Molten carbonate salts have received particular attention for high-temperature thermal energy storage and heat Molecular dynamics simulation transfer applications due to desirable thermal characteristics, such as wide operating temperature range, low Molten alkali carbonates causticity and excellent thermal stability. In this study, molecular dynamics (MD) simulations were performed Local structures on molten alkali carbonate K2CO3 based on an effective pair potential model, a Born-Mayer type combined with Thermodynamic properties a Coulomb term. The radial distribution functions (RDF) and coordination number curves of the molten salt were characterized to explore the temperature dependences of macroscopic properties from microscopic view. The results suggest that the distance between K2CO3 particles is getting larger with temperature increasing, resulting in the increase of molar volume and the diminished ability of resistance to shear deformation and heat transfer by vibration between ions. Besides, it can be concluded that the structure of CO32- is inferred reasonably to be ortho-triangular pyramid from the comprehensive analysis of local structures including the angular distribution functions (ADF). Moreover, the thermodynamic properties were simulated in detail from 1200 to 1600 K including the density, thermal expansion coefficient, specific heat capacity, sheer viscosity, thermal conductivity and ion self-diffusion coefficient, which was hard to be measured from experiments under high-temperature extreme conditions, All the simulation results are in satisfactory agreement with available experimental data with high accuracy, and the minimum simulation error is as low as 1.42%.

  • 33.
    Ding, Jing
    et al.
    Sun Yat Sen Univ, Sch Engn, Guangzhou 510006, Guangdong, Peoples R China..
    Du, Lichan
    Sun Yat Sen Univ, Sch Engn, Guangzhou 510006, Guangdong, Peoples R China..
    Pan, Gechuanqi
    Sun Yat Sen Univ, Sch Engn, Guangzhou 510006, Guangdong, Peoples R China..
    Lu, Jianfeng
    Sun Yat Sen Univ, Sch Engn, Guangzhou 510006, Guangdong, Peoples R China..
    Wei, Xiaolan
    South China Univ Technol, Sch Chem & Chem Engn, Guangzhou 510640, Guangdong, Peoples R China..
    Li, Jiang
    Natl Supercomp Ctr Guangzhou, Guangzhou 510006, Guangdong, Peoples R China..
    Wang, Weilong
    Sun Yat Sen Univ, Sch Engn, Guangzhou 510006, Guangdong, Peoples R China..
    Yan, Jinyue
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemical Engineering, Energy Processes. Mälardalen Univ, Sch Business Soc & Energy, Västerås, Sweden.
    Molecular dynamics simulations of the local structures and thermodynamic properties on molten alkali carbonate K2CO32018In: Applied Energy, ISSN 0306-2619, E-ISSN 1872-9118, Vol. 220, p. 536-544Article in journal (Refereed)
    Abstract [en]

    Molten carbonate salts have received particular attention for high-temperature thermal energy storage and heat Molecular dynamics simulation transfer applications due to desirable thermal characteristics, such as wide operating temperature range, low Molten alkali carbonates causticity and excellent thermal stability. In this study, molecular dynamics (MD) simulations were performed Local structures on molten alkali carbonate K2CO3 based on an effective pair potential model, a Born-Mayer type combined with Thermodynamic properties a Coulomb term. The radial distribution functions (RDF) and coordination number curves of the molten salt were characterized to explore the temperature dependences of macroscopic properties from microscopic view. The results suggest that the distance between K2CO3 particles is getting larger with temperature increasing, resulting in the increase of molar volume and the diminished ability of resistance to shear deformation and heat transfer by vibration between ions. Besides, it can be concluded that the structure of CO32- is inferred reasonably to be ortho-triangular pyramid from the comprehensive analysis of local structures including the angular distribution functions (ADF). Moreover, the thermodynamic properties were simulated in detail from 1200 to 1600 K including the density, thermal expansion coefficient, specific heat capacity, sheer viscosity, thermal conductivity and ion self-diffusion coefficient, which was hard to be measured from experiments under high-temperature extreme conditions, All the simulation results are in satisfactory agreement with available experimental data with high accuracy, and the minimum simulation error is as low as 1.42%.

  • 34. Duic, Neven
    et al.
    Guzovic, Zvonimir
    Kafarov, Vyatcheslav
    Klemes, Jiri Jaromir
    Mathiessen, Brian vad
    Yan, Jinyue
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Energy Processes.
    Sustainable development of energy, water and environment systems2013In: Applied Energy, ISSN 0306-2619, E-ISSN 1872-9118, Vol. 101, p. 3-5Article in journal (Refereed)
    Abstract [en]

    The 6th Dubrovnik Conference on Sustainable Development of Energy, Water and Environment Systems (SDEWES Conference), attended by 418 scientists from 55 countries representing six continents. It was held in 2011 and dedicated to the improvement and dissemination of knowledge on methods, policies and technologies for increasing the sustainability of development, taking into account its economic, environmental and social pillars, as well as methods for assessing and measuring sustainability of development, regarding energy, transport, water and environment systems and their many combinations.

  • 35. Epple, Bernd
    et al.
    Lyngfelt, Anders
    Adanez, Juan
    Yan, Jinyue
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Energy Processes.
    The 2nd International Conference on Chemical Looping 20122014In: Applied Energy, ISSN 0306-2619, E-ISSN 1872-9118, Vol. 113, p. 1827-1829Article in journal (Refereed)
  • 36.
    Erlich, Catharina
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
    Fransson, Torsten
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
    Downdraft gasification of pellets made of wood, palm-oil residues respective bagasse: Experimental study2011In: Applied Energy, ISSN 0306-2619, E-ISSN 1872-9118, Vol. 88, no 3, p. 899-908Article in journal (Refereed)
    Abstract [en]

    The downdraft gasification technology has an increased interest among researchers worldwide due to the possibility to produce mechanical and electrical power from biomass in small-scale to an affordable price. The research is generally focused on improvement of the performance and optimizing of a certain gasifier, on testing different fuels, on increasing the user-friendliness of the gasifier and on finding other uses for the product gas than in an IC-engine, for example liquid fuel production.

    The main objective with the gasification tests presented here is to further contribute in the field by studying the impact of the char bed properties such as char bed porosity and pressure drop on the gasification performance as well as the impact of fuel particle size and composition on the gasification process in one and the same gasifier. In addition, there is very little gasification data available in literature of “before disregarded” fuels such as sugar cane bagasse from sugar/alcohol production and empty fruit bunch (EFB) from the palm-oil production. By pelletizing these residues, it is possible to introduce them into downdraft gasification technology which has been done in this study.

    The results show that one and the same reactor can be used for a variety of fuels in pellet form, but at varying air–fuel ratios, temperature levels, gas compositions and lower heating values. Gasification of wood pellets results in a richer producer gas while EFB pellets give a poorer one with higher contents of non-combustible compounds. In this gasification study, there is almost linear relation between the air–fuel ratio and the cold-gas efficiency for the studied fuels: Higher air–fuel ratios result in better efficiency. The pressure drop in the char bed is higher for more reactive fuels, which in turn is caused by low porosity char beds.

  • 37.
    Evangelopoulos, Panagiotis
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering.
    Kantarelis, Efthymios
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology.
    Yang, Weihong
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering.
    Experimental investigation of the influence of reaction atmosphere on the pyrolysis of printed circuit boards2017In: Applied Energy, ISSN 0306-2619, E-ISSN 1872-9118, Vol. 204, p. 1065-1073Article in journal (Refereed)
    Abstract [en]

    Printed circuit boards (PCB) are one of the most challenging fractions of waste electrical and electronic equipment (WEEE) in terms of recycling due to their complexity and diversity. Pyrolysis seems to be a promising alternative for production of energy carriers from its organic fraction with simultaneous recovery of metals. Reaction atmosphere is among the process parameters that affects the thermal decomposition as well as the products’ formation and distribution. In this study, the decomposition of two different PCB fractions in inert and steam atmospheres has been investigated by means of thermogravimetric analysis (TGA) and lab scale fixed bed reactor experiments. It was found that the decomposition of the tested materials in steam atmosphere starts at lower temperatures and proceeds slower compared to the N2 atmosphere. Moreover, a two-step decomposition has been observed on the PCB sockets fraction due to the fact that high amount of antimony oxide was present, a common additive for improving the flame retardancy, which have been also observed on previous studies (Wu et al., 2014). The presence of steam influence the pyrolysis gas composition and promotes additional vaporisation of antimony as verified by powder X-ray diffraction (XRD) and scanning electron microscopy (SEM). Finally, the liquid fraction has been qualitatively analysed using a GC/MS in order to determine the brominated compounds as well as other compounds that are produced from this process.

  • 38. Feng, J. -C
    et al.
    Yan, Jinyue
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Energy Processes. Mälardalen University, Sweden.
    Yu, Z.
    Zeng, X.
    Xu, W.
    Case study of an industrial park toward zero carbon emission2018In: Applied Energy, ISSN 0306-2619, E-ISSN 1872-9118, Vol. 209, p. 65-78Article in journal (Refereed)
    Abstract [en]

    Industrial park shoulders heavy responsibilities for economic development, and in the meantime, acts the role as energy consumer and carbon emitter. Under the background of holding the average global temperature increase limited in 2 °C compared to the pre-industrial level, which was proposed in the Paris Agreement, the development of zero carbon emission at the industrial park level is of great importance. This study investigated how to realize zero carbon emission at an industrial park level. In addition, a practical case study of the Southern China Traditional Chinese Medicine Industrial Park located in the Zhongshan City, Guangdong Province of China was conducted. Scenario analyses were projected to realize zero carbon emission in this industrial park and the results show that zero carbon emission can be realized under all the three scenarios. Economic assessments found that purchasing carbon offsets get the minimum cost effectiveness under current market situation. However, purchasing carbon offset may not be the best choice from the aspect of absolute reduction. Sensitivity analyses illustrate that the cost effectiveness of carbon reduction is remarkably influenced by the carbon price and solar energy cost reduction ratio. Meanwhile, applying large-scale renewable energy and producing more carbon offset can harvest more economic and carbon reduction benefits when the current solar energy cost has been reduced by 90%. Moreover, challenges of building zero-carbon industrial park as well as the corresponding solution schemes were discussed.

  • 39.
    Fischer, David
    et al.
    Fraunhofer Institute for Solar Energy Systems, Germany.
    Bernhardt, J.
    Madani, Hatef
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Applied Thermodynamics and Refrigeration.
    Wittwer, C.
    Comparison of control approaches for variable speed air source heat pumps considering time variable electricity prices and PV2017In: Applied Energy, ISSN 0306-2619, E-ISSN 1872-9118, Vol. 204, p. 93-105Article in journal (Refereed)
    Abstract [en]

    The influence of different control strategies and boundary conditions on heat pump system performance are investigated in this study and the trade-off between complexity and performance of different controllers is addressed. For this purpose five different control approaches for a variable speed air source heat pump in a multi family house are compared for three different use-cases. The used controls differ in complexity and the use of external input data like price and weather forecasts. The use-cases are: Constant electricity prices, time variable electricity prices and PV self-consumption. Four different rule-based controllers are compared to a convex MPC approach, presented in this work. Results show that the MPC approach reduces annual operating cost by 6–11% for constant electricity prices and 6–16% in the case of variable electricity prices. Rule-based approaches lead to cost reductions of 2–4%. MPC could increases PV self-consumption from 56% to 58% up to 64–71%. The rule base approaches are found computationally less demanding and easier to design. However fine-tuning has been considerable work and with changing boundary conditions rules had to be readjusted. It showed that increasing thermal storage without MPC is not beneficial and optimised controls are a prerequisite to benefit from increased storage sizes.

  • 40. Gao, Xuerui
    et al.
    Liu, Jiahong
    Zhang, Jun
    Yan, Jinyue
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Energy Processes.
    Bao, Shujun
    Xu, He
    Qin, Tao
    Feasibility evaluation of solar photovoltaic pumping irrigation system based on analysis of dynamic variation of groundwater table2013In: Applied Energy, ISSN 0306-2619, E-ISSN 1872-9118, Vol. 105, p. 182-193Article in journal (Refereed)
    Abstract [en]

    Solar photovoltaic (PV) pumping irrigation system has become a widely applied solar energy technology over the past decades, in which the pump is driven by electricity produced by solar energy and lifts groundwater or surface water to irrigate the crop or grassland for agriculture. Qinghai Province, located in the Qinghai-Tibet Plateau, features abundant solar energy, but the problem of local grassland degradation and ecological deterioration has become increasingly serious. Using the clean solar energy to pump groundwater or surface water is of great significance for grassland recovery, environment protection and ecological restoration. In this study, we selected a demonstration site (with an area of 3.15 ha) in Tibetan Autonomous Prefecture of Golog at the southern part of Qinghai Province and evaluated the feasibility and performance of the PV pumping irrigation system at field scale. Firstly, water demand of pasture was predicted in different hydrological level years to determine water deficiency, which should be replenished mainly by pumping groundwater according to the local water resources conditions. Secondly, through modeling the unsteady flow of partially penetrating well in unconfined aquifer, we analyzed the change of groundwater table of the pumping well in both irrigation season and non-irrigation season, and then evaluated whether the groundwater resources can satisfy the pumping water demand for the growth of grassland. Results show that groundwater resources in the demonstration area are satisfactory and water yield in the pumping well can generally fulfill the water demand of grassland. Finally, based on balance analysis between solar energy supply and demand, a set of technical parameters were given to design the PV pumping irrigation system in the demonstration area. We also made the benefit analysis for the PV pumping irrigation system. It is concluded that, the PV system has good economic and ecological performance in the demonstration site compared to the diesel engine irrigation system, showing promising prospects to be popularized in Western China at large scale.

  • 41. García, A.
    et al.
    Partl, Manfred Norbert
    KTH, School of Architecture and the Built Environment (ABE), Transport Science, Highway and Railway Engineering.
    How to transform an asphalt concrete pavement into a solar turbine2014In: Applied Energy, ISSN 0306-2619, E-ISSN 1872-9118, Vol. 119, p. 431-137Article in journal (Refereed)
    Abstract [en]

    Asphalt concrete can absorb a considerable amount of the incident solar radiation. For this reason asphalt roads could be used as solar collectors. There have been different attempts to achieve this goal. All of them have been done by integrating pipes conducting liquid, through the structure of the asphalt concrete. The problem of this system is that all pipes need to be interconnected: if one is broken, the liquid will come out and damage the asphalt concrete. To overcome these limitations, in this article, an alternative concept is proposed:parallel air conduits, where air can circulate will be integrated in the pavement structure. The idea is to connect these artificial pore volumes in the pavement to an updraft or to a downdraft chimney. Differences of temperature between the pavement and the environment can be used to create an air flow, which would allow wind turbines to produce an amount of energy and that would cool the pavement down in summer or even warm it up in winter. To demonstrate that this is possible, an asphalt concrete prototype has been created and basics calculations on the parameters affecting the system have been done. It has been found that different temperatures, volumes of air inside the asphalt and the difference of temperature between the asphalt concrete and the environment are critical to maximize the air flow through the pavement. Moreover, it has been found that this system can be also used to reduce the heat island effect.

  • 42. Geng, Y.
    et al.
    Wei, Y. -M
    Fischedick, M.
    Chiu, A.
    Chen, B.
    Yan, Jinyue
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Energy Processes. Malardalen University (MDU), Sweden.
    Recent trend of industrial emissions in developing countries2016In: Applied Energy, ISSN 0306-2619, E-ISSN 1872-9118, Vol. 166, p. 187-190Article in journal (Refereed)
    Abstract [en]

    Greenhouse gas (GHG) emissions from industrial sectors are increasing, particularly in the developing world where pursuing industrialization has been highly addressed. This calls for further studies to learn and share experiences for developing countries. In order to fill in such a research gap, this special issue focuses on examining the recent trend of industrial emissions in developing countries. Among the manuscripts submitted to the Special Issue, twelve papers have been accepted after review, covering assessment indicators, tools and methods, and policies. Key industrial sectors, including cement, lime, aluminum, coal, mining, glass, soda ash, etc, have been investigated. Valuable policy insights have been raised, including wide scale upgrading, replacement and deployment of best available technologies, integrated information platforms, cross-cutting technologies and measures, a shift to low carbon electricity, radical product innovations, carbon dioxide capture and storage (CCS), demand on new and replacement products, systematic approaches and collaboration among different industries. These useful suggestions could be shared or learned by industrial policy makers or managers in the developing world so that the overall GHG emissions from their industrial sectors can be mitigated by considering the local realities.

  • 43.
    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.

  • 44.
    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.

  • 45.
    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.

  • 46.
    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.

  • 47. 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.

  • 48. 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.

  • 49. 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%.

  • 50.
    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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