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  • 1.
    Karampour, Mazyar
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Applied Thermodynamics and Refrigeration.
    Carlos, Mateu-Royo
    Department of Mechanical Engineering and Construction, Universitat Jaume I, Campus de Riu Sec s/n, E12071 Castelló de la Plana, Spain.
    Rogstam, Jörgen
    Energi & Kylanalys AB, Varuvägen 9, 125 30 Älvsjö, Sweden .
    Sawalha, Samer
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Applied Thermodynamics and Refrigeration.
    Geothermal Storage Integration into a Supermarket’s CO2 Refrigeration System2019In: International journal of refrigeration, ISSN 0140-7007, E-ISSN 1879-2081, Vol. 106, p. 492-505Article in journal (Refereed)
    Abstract [en]

    This paper investigates the integration of geothermal storage into state-of-the-art CO2 trans-critical boostersystems. The objective is to evaluate the impact of this integration on energy efficiency. Three scenarios of integration are studied including stand-alone and integrated supermarket building systems. The results show that for a stand-alone average size supermarket, heat recovery from the CO2 system should be prioritized over a separate ground source heat pump. Extracting heat from the ground by an extra evaporator in the CO2 system has also little impact on this supermarket annual energy use. However, in the case of supermarket integration with a neighbouring building where the supermarket provides heat to the neighbour, geothermal storage integration can reduce the total annual running cost of the two non-integrated buildings by 20-30% with a payback time of less than 3.5 years. The results also show there is no need for a separate ground source heat pump.

    The full text will be freely available from 2021-05-23 00:00
  • 2.
    Karampour, Mazyar
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Applied Thermodynamics and Refrigeration.
    Carlos, Mateu-Royo
    ISTENER Research Group, Department of Mechanical Engineering and Construction, Universitat Jaume I, Campus de Riu Sec s/n, E12071 Castelló de la Plana, Spain .
    Rogstam, Jörgen
    Energi & Kylanalys AB, Varuvägen 9, Älvsjö 125 30, Sweden .
    Sawalha, Samer
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Applied Thermodynamics and Refrigeration.
    Integration of Supermarket’s CO2 Refrigeration System and Geothermal Storage2019Conference paper (Refereed)
    Abstract [en]

    This paper investigates the energy efficiency of geothermal storage integration into the state-of-the-art CO2 trans-critical booster systems. Three scenarios of integration are studied including stand-alone and integrated supermarket building systems.

    The results show that for a stand-alone supermarket, heat recovery from the CO2 system should be prioritized over extracting heat from the ground, which this heat extraction can be done either by an extra evaporator in the CO2 system or by a separate ground source heat pump. In the case of supermarket integration with a nearby district heating consumer, geothermal storage integration with extra evaporator in the CO2 refrigeration system can reduce the total annual running cost of the two buildings by 19-31% and with a payback time of less than three years.

    This integration is beneficial if the full efficient heat recovery capacity of the CO2 system is not sufficient to provide the entire demands.

  • 3.
    Karampour, Mazyar
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Applied Thermodynamics and Refrigeration.
    Sawalha, Samer
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Applied Thermodynamics and Refrigeration.
    Energy Efficiency Evaluation of Integrated CO2 Trans-critical System in Supermarkets: A Field Measurements and Modelling Analysis2017In: International journal of refrigeration, ISSN 0140-7007, E-ISSN 1879-2081, Vol. 82, p. 470-486Article in journal (Refereed)
    Abstract [en]

    This paper investigates energy efficiency of an integrated CO2 trans-critical booster system installed in a supermarket in Sweden. The supermarket has applied several features to improve energy efficiency including space and tap water heating, air conditioning (AC), and parallel compression.  

    Using field measurements data, the system performance is evaluated in a warm and a cold month. Furthermore, this integrated energy system concept is modelled and compared with stand-alone HFC-based energy systems. 

    The results show that the system provides the entire AC demands and recovers a great share of the available heat, both with high COP values. The comparative analysis shows that integrated CO2 system uses about 11% less electricity than stand-alone HFC solutions for refrigeration (i.e. indirect HFC), heating and AC in North of Europe.

    Energy efficiency analysis of the integrated CO2 system proves that this system is an environmentally friendly all-in-one energy efficient solution suitable for cold climate supermarkets.

  • 4.
    Karampour, Mazyar
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Applied Thermodynamics and Refrigeration.
    Sawalha, Samer
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Applied Thermodynamics and Refrigeration.
    Carlos, Mateu-Royo
    ISTENER Research Group, Department of Mechanical Engineering and Construction, University Jaume I, Castellón de la Plana, Spain.
    Rogstam, Jörgen
    Energi & Kylanalys AB, Älvsjö, Sweden.
    Geothermal Storage Integration into Supermarket’s CO2 Refrigeration System2018In: Proceedings of the IGSHPA Research Track 2018, 2018Conference paper (Refereed)
    Abstract [en]

    This paper investigates the integration of geothermal storage into the state-of-the-art CO2 trans-critical booster systems. The objective is to evaluate the impact on energy efficiency of this integration. Three scenarios of integration are studied including stand-alone and integrated supermarket building systems. The results show that for a stand-alone supermarket, heat recovery from the CO2 system should be prioritized over extracting heat from the ground, which can be done either by an extra evaporator in the CO2 system or by a separate ground source heat pump. In the case of supermarket integration with a nearby district heating consumer, geothermal storage integration with extra evaporator in the CO2 refrigeration system can reduce the total annual running cost of the two buildings by 20-30%. The determining factors on profitability of geothermal storage integration are the heating demand of the supermarket and possibilities of coupling its heating system to another nearby consumer. This integration is beneficial if the full efficient heat recovery capacity of the CO2 system is not sufficient to provide the entire demands.

  • 5.
    Mateu-Royo, Carlos
    et al.
    KTH.
    Karampour, Mazyar
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Applied Thermodynamics and Refrigeration.
    Rogstam, J.
    Sawalha, Samer
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Applied Thermodynamics and Refrigeration.
    Integration of geothermal storage in CO2 refrigeration systems of supermarkets2018In: Refrigeration Science and Technology, International Institute of Refrigeration, 2018, p. 1265-1272Conference paper (Refereed)
    Abstract [en]

    The aim of this paper is to study the benefits of integrating CO2 trans-critical booster refrigeration system with geothermal storage. The ground is used as a heat sink for sub-cooling during the summer period and as a heat source for extracting heat in the winter season. Using field measurements from medium size supermarkets in Sweden, proposed and the existing system solutions for integrating geothermal storage in CO2 refrigeration systems are modelled and compared with standard CO2 trans-critical booster system. The techno-economical comparative analysis shows that hybrid CO2 trans-critical booster system with ground source heat pump (GSHP) as an integrated geothermal solution has 6% lower annual energy use compared to a stand-alone CO2 system with heat recovery.

  • 6. Purohit, Nilesh
    et al.
    Sharma, Vishaldeep
    Sawalha, Samer
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Applied Thermodynamics and Refrigeration.
    Fricke, Brian
    Llopis, Rodrigo
    Dasgupta, Mani Sankar
    Integrated supermarket refrigeration for very high ambient temperature2018In: Energy, ISSN 0360-5442, Vol. 165, p. 572-590Article in journal (Refereed)
    Abstract [en]

    This paper analytically investigates and compares the performance of a proposed ‘all-natural’ NH3/CO2 cascaded booster system to a conventional R404A direct expansion system as well as to an ‘all-CO2’ system with multi-ejector unit and flooded evaporator. Performance comparison is made based on the annual combined COP and Life Cycle Climate Performance (LCCP) for operation in selected cities of Middle East and India. Our results show that in extreme warm climate, the energy efficiency of the proposed configuration exceeds that of all-CO2 configuration by a maximum of about 12.23% and the total emissions are lower by up to 11.20%. However, the all-CO2 multi ejector system performs better in cold and mild warm climate. In the NH3/CO2 cascade, the high temperature NH3 system can be designed to be isolated from the accessible locations of the supermarket. The work presented is expected to help adoption of natural refrigerants such as CO2 and NH3 for commercial application in extreme warm climate conditions prevailing in many cities of Middle East and India.

    The full text will be freely available from 2021-10-30 16:19
  • 7. Raka Adrianto, Lugas
    et al.
    Grandjean, Pierre-Alexandre
    Sawalha, Samer
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Applied Thermodynamics and Refrigeration.
    Heat Recovery from CO2 Refrigeration System in Supermarkets to District Heating Network2018Conference paper (Refereed)
    Abstract [en]

    In the process of moving towards sustainable energy systems for future cities, the district heating system will have to be more dynamic and accessible to the different heating sources available in the society. A main potential heat source to be connected to the district heating network is the heat rejected from refrigeration systems in supermarket applications.

     

    This paper investigates the main possible scenarios for recovering heat from supermarket refrigeration system with CO2 as the refrigerant. The efficiency of the refrigeration system under the different heat recovery scenarios is studied with the aid of computer modelling. The cost of producing the recoverable heat is calculated and compared to market price from local district heating company. The total energy cost for running the system in the winter season in the different scenarios is also calculated.

     

    This study shows that the best scenario is to recover heat for space heating in the supermarket building as a priority and then recover all or part of the remaining available heat to district heating. In an average size supermarket in Sweden, all the space heating demand can be recovered from the refrigeration system with space heat recovery COP (i.e. heating COP) of about 4.5 in average. To produce 1 kW heat supplied to district heating, 2/5 to 1/8 kW of compressor power is used; i.e. district heating recovery COP is 2.5-8. This scenario results in the lowest annual energy cost of the system, about 40% lower than the reference scenario, where the refrigeration system runs at floating condensing and space heating is delivered by district heating.

  • 8.
    Sawalha, Samer
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Applied Thermodynamics and Refrigeration.
    Korttidslagring av energi med fasändringmaterial för effektiv integrering med värme- och kylsystem i byggnader-Effsys Expand projekt på KTH2016Other (Other (popular science, discussion, etc.))
    Abstract [sv]

    International Energy Agency (IEA) presenterade nyligen sin plan för energieffektiva byggnader där termisk energilagring lyfts som en av fyra nyckelkomponenter i byggnaders värme- och kylsystem. PCM-baserad (Phase Change Materials – fasändringsmaterial) termisk energilagring (PCM-TES) har några fördela jämfört sensibla lager: kompakta system (hög energidensitet), samt lagring i ett litet temperaturintervall. Sådana egenskaper gör det lättare att integrera och nyttja förnybar energi (t ex solvärme och frikyla), realisera byggnadskoncept för lågenergi/passivhus, samt ökar effektiviteten i utrustning såsom värmepumpar och kylmaskiner.

  • 9.
    Sawalha, Samer
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Applied Thermodynamics and Refrigeration.
    Abdi, Amir
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology.
    Värmeåtervinning med CO2 i livsmedelsbutikers kylanläggningar. – Hur ska den styras och hur effektiv kan den bli?2013Other (Other (popular science, discussion, etc.))
    Abstract [sv]

    Kylanläggningar i livmedelsbutiker har ofta stort energibehov och antalet installationer ökar oavbrutet. I ett typiskt livsmedelsbutiks installation i Sverige går 35-50% av det totala elbehovet åt för att driva kylanläggningarna (Lundqvist, 2000). Situationen i USA är likartad (Richard Royal, 2010; Arthur D. Little Inc, 1996). Samtidigt avger kyl- och frysanläggningarna avsevärda energimängdeer i form av värme som skulle kunna utnyttjas för att täcka eller åtminstone reducera behovet för värme och varmvatten. 

  • 10.
    Sawalha, Samer
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Applied Thermodynamics and Refrigeration.
    Arias Hurtado, Jaime
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Applied Thermodynamics and Refrigeration.
    Karampour, Mazyar
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Applied Thermodynamics and Refrigeration.
    Rogstam, Jörgen
    Abdi, Amir
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology.
    Forskning på KTH om livsmedelskyla-En översikt.2014Other (Other (popular science, discussion, etc.))
    Abstract [sv]

    På avdelningen för Tillämpad Termodynamik och kylteknik, Institutionen för Energiteknik på KTH har vi arbetat med livsmedelskyla för butiker och stormarkander sedan mer än 15 år. Detta har skett inom ramen för olika projekt och med olika inriktning, innefattande datorsimuleringar, experimentella arbeten och fältmätningar. Vi har därigenom byggt upp en gedigen kompetens inom området och vi har också tillgång till värdefulla vetenskapliga verktyg för att belysa olika fundamentala frågeställningar inom området som på senare år undergått en mycket dynamisk utveckling.

  • 11.
    Sawalha, Samer
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Applied Thermodynamics and Refrigeration.
    Karampour, Mazyar
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Applied Thermodynamics and Refrigeration.
    Dagens effektivaste livsmedelsbutik är definierad; den kommer att byggas och verifieras i en verklig livsmedelsbutik2018Other (Other (popular science, discussion, etc.))
    Abstract [sv]

    Projektet ”Morgondagens energieffektiva livsmedelsbutik” avslutades i februari 2018. Det har letts av KTH och genomförts i samarbete med en grupp industripartner, och medfinansierats av Energimyndigheten inom ramen för Effsys EXPAND-program. Projektet har utforskat en ökning av effektiviteten hos standardkoldioxidkylsystem i livsmedelsbutiker genom att undersöka ändringar av utformningen och möjligheterna att integrera systemen med andra energisystem i livsmedelsbutiken.

  • 12.
    Xu, Tianhao
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology. KTH.
    Chiu, Justin NingWei
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology.
    Palm, Björn
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology.
    Sawalha, Samer
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology.
    Experimental investigation on cylindrically macro-encapsulated latent heat storage for space heating applications2019In: Energy Conversion and Management, ISSN 0196-8904, E-ISSN 1879-2227, Vol. 182, p. 166-177Article in journal (Refereed)
    Abstract [en]

    The integration of latent heat thermal energy storage (LHTES) units with heating systems in buildings is regarded as a promising technology for heating load management; however, so far a limited number of experimental studies have been reported that focus on space heating applications on a representative scale. In this study, we develop and test a 0.38 m3 LHTES unit containing cylindrically macro-encapsulated phase change materials (PCMs) with a melting temperature range of 44–53 °C and with gross mass of 154 kg. The unit has been tested with two tank orientations, horizontal and vertical. In the horizontal orientation tests, parametric studies show that increasing the difference between heat transfer fluid (HTF) supply temperatures and phase-change temperatures of PCMs, as well as increasing HTF flowrates, can both reduce the complete melting/solidification and complete charging/discharging time. Non-linear charging/discharging rates in PCMs are observed. The vertical orientation enables the forming of either a stratified or mixed flow regime in the tank. For charging, the stratified flow provides higher charging rates in PCMs compared to the mixed flow. When discharging the unit with a stratified HTF flow at 35 °C, lower HTF flowrates prolong the discharging time during which the released heat sustains an outlet temperature above 45 °C. Finally, comparisons between horizontal and vertical orientation tests reveal that although the vertical orientation can shorten the charging/discharging time by up to 20% for the entire unit to reach an energy density of 30 kWh/m3, it leads to decrease in PCM thermal capacity by at most 8.2%. The speculated cause of this loss is phase segregation suggested by observed fluid motions in PCM cylinders. This study comprehensively characterizes an LHTES unit providing insights to optimizing its operating strategies considering its coupling with space heating systems.

  • 13.
    Xu, Tianhao
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology.
    Navarro-Peris, Emilio
    Piscopiello, Salvatore
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology.
    Sawalha, Samer
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Applied Thermodynamics and Refrigeration.
    Corberán, José M.
    Palm, Björn
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Applied Thermodynamics and Refrigeration.
    Large-Capacity Propane Heat Pumps for DHW Production in Residential Buildings2018In: Refrigeration Science and Technology, Valencia, Spain, 2018, p. 1222-1230Conference paper (Refereed)
    Abstract [en]

    Using heat pump technology to provide Space Heating (SH) and to produce Domestic Hot Water (DHW) for residential buildings has been widely applied during past decades. In this study, two scenarios adopting large-capacity propane heat pumps are defined and evaluated. These two scenarios, which are named after Scenario A and Scenario B respectively, provide SH and DHW either separately by two units or integrally by one unit. The COP1s of two scenarios are compared based on the simulation results from experimentally validated models. The results show that two scenarios have almost equal efficiency; the relative difference is within 6%. In the optimization analysis of Scenario B, varying DHW heating capacity produced by the desuperheater in the heat pump is modelled. The DHW demand ratio varies from approximately 9% to 20% with no detectable influences on the COP1. The corresponding COP1s and temperature profiles in the heat exchangers are demonstrated. The simulation results indicate that increasing DHW capacity in Scenario B can narrow down the temperature approach in the condenser and insignificantly improves the overall COP1s.

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