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  • 1.
    Abdi, Amir
    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.
    Karampour, Mazyar
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Applied Thermodynamics and Refrigeration.
    Heat recovery investigation of a supermarket refrigeration system using carbon dioxide as refrigerant2014In: 11th IIR Gustav Lorentzen Conference on Natural Refrigerants: Natural Refrigerants and Environmental Protection, GL 2014, International Institute of Refrigeration, 2014, p. 277-285Conference paper (Refereed)
    Abstract [en]

    This study investigates the heat reclaim of trans-critical CO2-booster refrigeration unit in a supermarket in Sweden. The aim is to compare the control strategy for heat recovery in real supermarket installation to the optimum control strategy.

    The optimum control strategy based on theoretical analysis is explained. By analyzing field measurement of a supermarket, heat recovery in the refrigeration system is studied and compared to the optimum case. To investigate the potential of higher heat recovery rate, a computer model is developed based on the optimum control strategy.  The model is also used to calculate the boundary conditions at which the system should run for highest COP.

    The results show that heat can be recovered at heating COP of 3-4.5. The theoretical analysis shows that the amount of heat that can be recovered from the refrigeration system is about 1.3 times (130 %) the cooling demand in the system. However the analysis of the field measurements shows that only between 30-60 % of the available heat to be recovered is utilized, the rest is released to outdoors. The analysis in this study shows that there is a potential to recover much more heat from the refrigeration system at relatively high heating COP compared to heat pump.

  • 2.
    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
  • 3.
    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.

  • 4.
    Karampour, Mazyar
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Applied Thermodynamics and Refrigeration.
    Rogstam, Jörgen
    Measurement and Modelling of Ice Rink Heat Loads2012Conference paper (Refereed)
    Abstract [en]

    Ice rinks are among the most energy intensive public buildings. According to previous studies a typical ice rink consumes about 1000 MWh/year, and the refrigeration system is typically the largest consumer. Consequently, the first step to decrease their energy demand is to find major heat loads on the ice. To fulfil this objective the study has two main approaches. The first approach is to evaluate the performance of the refrigeration system in two ice rinks. The estimated cooling capacity is approximately equal to the total heat load on the ice plus the heat gains in the distribution system. This goal has been accomplished by using a performance analyser. It uses compressor as an internal mass flow meter. While the total heat load is known by the first approach, the second approach discovers different heat loads shares by analytical modelling. The measured physical and thermodynamical parameters plus the ice rink geometrical characteristics are input to the heat transfer correlations to estimate the respective heat loads. The results of the measurements show that the total refrigeration system energy consumption in the first ice rink is about two third of the second. The main reasons for the lower energy consumption are smarter control systems for compressors and pumps, better ventilation distribution design and 1-2°C higher ice temperature. Calculations show that convection, radiation, ice resurfacing and lighting are the largest heat loads in winter while in summer condensation is another significant heat load. To conclude, a parallel “performance analysis of the refrigeration system” and “heat loads estimation” proved to be a useful tool for adopting proper design and control policies.

  • 5.
    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.
    Comparison of State-of-the-art CO2 and Alternative Refrigeration Systems for Supermarkets2018In: 13th IIR Gustav Lorentzen Conference on Natural Refrigerants, Valencia, Spain, 2018, p. 1298-1306Conference paper (Refereed)
    Abstract [en]

    This paper investigates the state-of-the art features of CO2 trans-critical booster systems. The performance of various modified features have been compared to the standard CO2 booster system. Subsequently, the performance of the defined state-of-the-art CO2 system is compared to natural refrigerant-based cascade, HFC/HFO-based DX and indirect refrigeration solutions, and propane water-cooled plug-ins operating in cold and warm climates. The results indicate that flooded evaporation and parallel compression are the most promising features of the state-of-the-art CO2 system. This compact and environmentally friendly system is the most energy efficient solution in cold climates, and is also an efficient solution in warm climates, with comparable efficiency to cascade and HFC/HFO DX systems, but with no existing or potential limitations.

  • 6.
    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.

  • 7.
    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.
    Integration of heating and air conditioning into a CO2 trans-critical booster system with parallel compression part II: Performance analysis based on field measurements2016In: Refrigeration Science and Technology, International Institute of Refrigeration , 2016, p. 332-340Conference paper (Refereed)
    Abstract [en]

    This paper investigates the energy efficiency performance of an integrated CO2 trans-critical booster system providing refrigeration, heating and air conditioning demands of a small-medium size supermarket in Sweden. Using a computer model and input data from field measurements (data presented in part-I of this paper), the system loads and energy efficiencies are evaluated for a warm summer month and a cold winter month. Having analysed the loads hourly and daily, the results show that the system is able to provide the entire air conditioning (AC) demands and a great share of the available heat is recovered for tap water and space heating. It is seen that the refrigeration energy efficiency hasn't been affected providing the heating and AC demands. Focusing on air conditioning (AC) function of the system, it is shown that the system has high COP values for Tamb<25°C, confirming that it is a suitable solution for northern Europe. On the use of parallel compression (PC) during AC delivery, it is found that COPAC and COPtot of the system are 25% and 8% higher using "AC with PC" comparing with "AC without PC", respectively. Heat recovery (HR) study indicates that CO2 system provides the heating demands with high COPHR values, usually within the 4-6 range and comparable to majority of commercial heat pumps in the market. To conclude, the energy efficiency study of the integrated CO2 system functions confirm that it can be used as an environmentally friendly all-in-one supermarket energy solution suitable for mild-cold climates. 

  • 8.
    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.
    Integration of Heating and Air Conditioning into a CO2 Trans-Critical Booster System with Parallel Compression-Part I: Evaluation of key operating parameters using field measurements2016In: 12th IIR Gustav Lorentzen Natural Working Fluids Conference, Edinburgh, Scotland, 2016, IIR , 2016Conference paper (Refereed)
    Abstract [en]

    This paper investigates key operating parameters of a supermarket in Sweden where heating and air conditioning are integrated into the CO2 trans-critical refrigeration system. The Supermarket has applied several features of a state-of-the-art system including space and tap water heating, air conditioning, and parallel compression. Using field measurements data, the key operating parameters in the CO2 system are studied in a warm summer month and a cold winter month. The warm month study shows that the CO2 system provides the required temperatures for air conditioning demands; the pressure in the receiver is regulated to provide 7-8°C forward secondary fluid. Parallel compression is used to control the receiver pressure for ambient temperatures higher than 15°C. The high pressure side of integrated CO2 system is controlled mainly for heat recovery in winter. The pressure is fixed to 80-85 [bar] and the gas cooler is by-passed to recover the entire rejected heat when ambient temperature is very low. The heat recovery function of the system is analysed for both tap water and space heating circuits. The measurements show that the system is able to provide the high tap water temperature of 55-60°C throughout the year. The system is also able to provide the space heating forward temperature of up to 45°C. Analysis of the key operating parameters of the integrated CO2 system shows that it fulfils the temperature requirements of refrigeration, air conditioning, hot water, and space heating. The loads and energy efficiency of these functions of the systems have been studied in part II of this paper.

  • 9.
    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.
    Investigation of using Internal Heat Exchangers in CO2 Trans-critical Booster System2014In: 11th IIR Gustav Lorentzen Conference on Natural Refrigerants: Natural Refrigerants and Environmental Protection, GL 2014, 2014, p. 453-460Conference paper (Refereed)
    Abstract [en]

    This paper theoretically investigates the performance of a CO2 trans-critical booster system using various configurations of internal heat exchangers (IHX). A reference case performance is compared with eight alternatives of using IHXs after the gas cooler and liquid receiver. Cooling COP, total COP and amount of heat recovery are the comparison criteria. Heat recovery or heat rejection from the discharge gas of low stage compressors is another modification examined in this study.

    According to the results, no significant improvement is found by using internal heat exchanger (IHX) focusing only on the cooling COP. Considering simultaneous refrigeration and heat recovery for a sample 65 bar discharge pressure, up to 12% efficiency improvement with IHX A-AC-AD for a system “with by-pass” and up to 11% improvement with IHX AC-AD-BC-BD for a system “without by-pass” is calculated. It is shown that superheating has less influence on the available heat to be recovered in the trans-critical region in comparison with the sub-critical region. Furthermore, low stage level heat recovery and de-superheating improves the efficiency 3-4% for the cases with high amount of de-superheating at low stage suction line, using IHX C or D.

    To conclude, using IHXs improves the performance of the CO2 booster system with heat recovery. This improvement is more significant in sub-critical region.

  • 10.
    Karampour, Mazyar
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology.
    Sawalha, Samer
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology.
    Investigation of using Internal Heat Exchangers inCO(2) Trans-critical Booster System2014In: 11TH IIR GUSTAV LORENTZEN CONFERENCE ON NATURAL REFRIGERANTS (2014): NATURAL REFRIGERANTS AND ENVIRONMENTAL PROTECTION / [ed] Hu, W Zhao, G, INT INST REFRIGERATION , 2014, p. 453-460Conference paper (Refereed)
    Abstract [en]

    This paper theoretically investigates the performance of a CO2 trans-critical booster system using various configurations of internal heat exchangers (IHX). A reference case performance is compared with eight alternatives of using IHXs after the gas cooler and liquid receiver. Cooling COP, total COP and amount of heat recovery arethe comparison criteria. Heat recovery or heat rejection from the discharge gas of low stage compressors is another modification examined in this study. According to the results, no significant improvement is found by using internal heat exchanger (IHX) focusing only on the cooling COP. Considering simultaneousrefrigeration and heat recoveryfor a sample 65 bar discharge pressure, up to 12% efficiency improvement with IHX A-AC-AD for a system "with by-pass" and up to 11% improvement with IHX AC-AD-BC-BD for a system "without by-pass" iscalculated. It isshown that superheating has less influence on the available heat to be recovered in the trans-critical region in comparison with the sub-critical region. Furthermore, low stage level heat recovery and desuperheating improves the efficiency 3-4% for the cases with high amount of de-superheatingat low stage suction line, using IHX C or D. To conclude, using IHXs improves the performance of the CO2 booster system with heat recovery. This improvement is more significant in sub-critical region.

  • 11.
    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.
    Performance and control strategies analysis of a CO2 trans-critical booster system2014Conference paper (Refereed)
    Abstract [en]

    This research paper theoretically studies the performance and control strategies of a CO2 trans-critical booster system. A computer simulation with field measurement-based inputs is used to analyse the performance of the system. Energy usage/efficiency indicators including cooling-heating loads, electricity use and COPs are presented and discussed for an entire year. Subsequently, some of the controlled parameters are varied to evaluate their significance in energy saving.

    According to the results, in the warm months, medium temperature cooling demand is 30-35% higher than cold months and the entire heat is rejected in the gas cooler while half of the dissipated heat is recovered in the de-superheater in cold months, following the suggested heat recovery control strategy. Considering the system as a heat pump, a high seasonal performance factor of 4 is achieved.   

    Studying the control parameters shows that lowering the gas cooler approach temperature and increasing evaporation temperature in cabinets and freezers are the most efficient methods for energy saving.

    CO2 trans-critical booster system with proper control strategies can provide the entire refrigeration and heating demands with high energy efficiency in relatively cold climates. 

  • 12.
    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.
    State-of-the-Art Integrated CO2 Refrigeration System for Supermarkets: a Comparative Analysis2018In: International journal of refrigeration, ISSN 0140-7007, E-ISSN 1879-2081, Vol. 86, p. 239-257Article in journal (Refereed)
    Abstract [en]

    This paper investigates the integrated and state-of-the art features of CO2 trans-critical booster systems. The main objective is to identify the most promising solutions in terms of energy efficiency impacts.

     

    First, the performance of modified features and integrated functions have been compared with the standard CO2 system and alternative heating and air conditioning solutions. Subsequently, the performance of the defined state-of-the-art CO2 system is compared to natural refrigerant-based cascade and HFC/HFO-based DX and indirect refrigeration solutions operating in cold and warm climates.

     

    The results indicate that two-stage heat recovery, flooded evaporation, parallel compression and integration of air conditioning are the most promising features of the state-of-the-art integrated CO2 system. This compact and environmentally friendly system is the most energy efficient solution in cold climates, and is also an efficient solution in warm climates, with comparable efficiency to cascade and HFC/HFO DX systems, but with no existing or potential limitations.

  • 13.
    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.
    Supermarket refrigeration and heat recovery using CO2 as refrigerant: A comprehensive evaluation based on field measurements and modelling2014Report (Refereed)
    Abstract [en]

    This project investigates the potentials, challenges and opportunities of using CO2 as refrigerant in the supermarket refrigeration and heat recovery systems. The focus is on CO2 trans-critical booster system, as the emerging state-of-the-art system in supermarket refrigeration field. The CO2 booster system performance is studied using computer modeling and field measurement analysis to find the most energy efficient ways for providing simultaneous cooling and heating demands in supermarkets. Through this research work, the solutions available on the market are investigated, suggestions on system modifications and optimization are made, and new system solutions are suggested.

  • 14.
    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.
    Theoretical analysis of CO2 trans-critical system with parallel compression for heat recovery and air conditioning in supermarkets2015In: Refrigeration Science and Technology, International Institute of Refrigeration, 2015, p. 2321-2328Conference paper (Refereed)
    Abstract [en]

    This paper theoretically analyses a CO2 trans-critical booster system in which parallel compression, heat recovery and air conditioning are integrated. The performance of the system is studied in various running modes using flash gas by-pass (FGBP) or parallel compression (PC). These running modes include summer cases with/without air conditioning and winter case with heat recovery. The results show that parallel compression is more efficient than flash gas by-pass in summer cases; the increase in COPtot is up to 14% comparing the best cases for PC and FGBP. The increase in COPtot in winter heat recovery mode is marginal, less than 4-6% and hardly-feasible in practice. Comparing the AC function of the CO2 system with a conventional HFC air conditioning system, it has been found that CO2 system is more efficient in moderate ambient temperatures lower than 20-25°C. The CO2 system's AC performance is less efficient than HFC solution in ambient temperatures higher than 25°C. To conclude, an integrated CO2 trans-critical booster system can to provide the entire supermarket's refrigeration and air conditioning demands for cold-mild climates with comparable or higher energy efficiency than the HFC solutions.

  • 15.
    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.
    Theoretical analysis of CO2 trans-critical system with parallel compression for heat recovery and air conditioning in supermarkets2015In: The 24th IIR International Congress of Refrigeration - ICR2015, Yokohama, Japan: International Institute of Refrigeration, 2015Conference paper (Refereed)
    Abstract [en]

    This paper theoretically analyses a CO2 trans-critical booster system in which parallel compression, heat recovery and air conditioning are integrated. The performance of the system is studied in various running modes using flash gas by-pass (FGBP) or parallel compression (PC). These running modes include summer cases with/without air conditioning and winter case with heat recovery.The results show that parallel compression is more efficient than flash gas by-pass in summer cases; the increase in COPtot is up to 14% comparing the best cases for PC and FGBP. The increase in COPtot in winter heat recovery mode is marginal, less than 4-6% and hardly-feasible in practice. Comparing the AC function of the CO2 system with a conventional HFC air conditioning system, it has been found that CO2 system is more efficient in moderate ambient temperatures lower than 20-25°C. The CO2 system’s AC performance is less efficient than HFC solution in ambient temperatures higher than 25°C.To conclude, an integrated CO2 trans-critical booster system can to provide the entire supermarket’s refrigeration and air conditioning demands for cold-mild climates with comparable or higher energy efficiency than the HFC solutions.

  • 16.
    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.
    Abdi, Amir
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Applied Thermodynamics and Refrigeration.
    Arias, Jaime
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Applied Thermodynamics and Refrigeration.
    Rogstam, Jörgen
    Review of supermarket refrigeration and heat recovery research at KTH-Sweden2015In: 6th IIR Conference: Ammonia and CO2 Refrigeration Technologies, Ohrid, Macedonia: International Institute of Refrigeration, 2015Conference paper (Refereed)
    Abstract [en]

    This paper reviews findings of main projects at the Royal Institute of Technology (KTH), Sweden on supermarket refrigeration and heat recovery systems. A main focus of the research has been on CO2 trans-critical booster system, as the emerging solution in the Swedish market, where its performance has been often compared with the conventional HFC solutions.The field measurements project investigates several supermarket installations with CO2 and conventional HFC systems, where detailed performance comparisons have been performed.In addition to the standard methods for field data analysis of refrigeration systems, a simplified method has been proposed to monitor the real-time performance of the refrigeration systems in a supermarket. Proper control strategy for heat recovery has also been investigated by computer modeling and field measurement analysis.Another major study has been examining the improvement of energy efficiency using short- and long-term thermal storage in supermarkets. Daily and yearly storage solutions have been proposed and studied in this project.Focusing on improvement in energy efficiency in supermarkets, state-of-the-art refrigeration systems have been defined for further investigations and an existing supermarket modeling software developed at KTH (CyberMart) is being upgraded to investigate the recent solutions in the market.

  • 17.
    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.
    Arias, Jaime
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Applied Thermodynamics and Refrigeration.
    Eco-friendly Supermarkets: an Overview2016Report (Refereed)
  • 18.
    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.

  • 19.
    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.
    Rogstam, Jörgen
    Field Measurements and Performance Evaluation of CO2 Supermarket Refrigeration Systems2013In: 2nd IIR International Conference on Sustainability and the Cold Chain. Proceedings: Paris, France, April 2-4, 2013, 2013Conference paper (Refereed)
    Abstract [en]

    This paper studies field measurements and performance analysis of eight supermarkets in Sweden amongwhich five supermarkets use CO2 and three use HFC as the refrigerant. The differences in system design arediscussed and detailed performance evaluation of one of the systems is presented. The performances of allthe supermarkets are compared and the reasons for higher or lower energy efficiency are discussed. Somekey components of CO2 systems are evaluated, as well.According to the results, the older CO2 systems have lower COP than the reference systems. High vapourfraction in low temperature cabinets inlet, relatively high amount of internal and external superheating and10-15% lower overall efficiency of low temperature compressors compared to the other systems are some ofthe main reasons for this lower COP. But, the newer CO2 systems proved to have higher efficiency, or atleast, as energy-efficient as the conventional systems. This originates from the modification in the systemdesign and more efficient components. System design modification includes two-stage expansion by receiverand flash gas by-pass. The newer CO2 components have higher efficiency; medium temperature levelcompressors have 5-10% higher overall efficiency compared to HFC and older CO2 compressors and thecabinets run with lower superheating so the system can be controlled to run at higher evaporationtemperatures.This study shows that CO2 systems have comparable COP to advanced conventional systems applied in Sweden.

  • 20.
    Kauko, Hanne
    et al.
    SINTEF.
    Husevåg Kvalsvik, Karoline
    SINTEF.
    Masson, Nina
    SHECCO.
    Noel, Christine
    SHECCO.
    Minetto, Silvia
    CNR.
    Rossetti, Antonio
    CNR.
    Marinetti, Sergio
    CNR.
    Thalheim, Diana
    UBA.
    Martens, Kerstin
    UBA.
    Karampour, Mazyar
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Applied Thermodynamics and Refrigeration.
    Piscopiello, Salvatore
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Applied Thermodynamics and Refrigeration.
    Fidorra, Nicolas
    TU Braunschweig.
    Gimeno Frontera, Beatriz
    CIRCE.
    Saez de Guinoa, Aitana
    CIRCE.
    Mainar Toledo, Lola
    CIRCE.
    Ciconkov, Samoil
    Energija .
    Ciconkov, Vasil
    Energija .
    Development of the EU Ecolabel Criteria for Food Retail Stores: Preliminary Report2017Report (Other academic)
  • 21.
    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.

  • 22. Piscopiello, Salvatore
    et al.
    Karampour, Mazyar
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Applied Thermodynamics and Refrigeration.
    Pressiani, Michele
    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.
    Guidelines of How to Instrument and Measure and Evaluate Refrigeration Systems in Supermarkets; with Focus on CO2 Trans-Critical Booster Systems2018In: 13th IIR Gustav Lorentzen Conference on Natural Refrigerants, International Institute of Refrigeration, 2018, p. 1289-1297Conference paper (Refereed)
    Abstract [en]

    This paper reviews the guidelines of how to instrument, measure, monitor and evaluate refrigeration systems in supermarkets. The guidelines principles are firstly illustrated for a simple, single stage, refrigeration system: measurements requirements are analysed and the methodology to estimate refrigeration quantities are defined. Estimation for refrigerant mass flow rate and compressor power are more extensively described and their application on real field measurement data presented and discussed. The extension of the guidelines for a more complex refrigeration system is finally presented with focus on centralized systems providing cooling a multiple temperature levels: a HFC system with LT subcooler and a simple CO2 booster system.

  • 23.
    Rogstam, Jörgen
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology.
    Karampour, Mazyar
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Applied Thermodynamics and Refrigeration.
    Experimental cooling load analysis of ice rinks2011In: 23rd International-Institute-of-Refrigeration, 2011, p. 2067-2074Conference paper (Refereed)
    Abstract [en]

    Ice rinks for ice hockey use approximately 1000 MWh per year. These figures are based on statistics from over 100 Swedish ice rinks. The refrigeration system accounts for in the range of 35 to 75% of the total energy usage in the ice rinks, with an average value of 43%. This study evaluated a method to field measure the refrigeration system to establish the cooling capacity, which with minor corrections is equal to the ice surface heat load. The performance of the distribution system and at the main components of the heat load is in focus in this study. To analyze the performance of the ice rinks refrigeration system an "internal method" was used. In this method the compressor is used as a mass flow meter and therefore there is no need installing an external mass flow meter. The refrigerant mass flow rate is calculated by an energy balance over the compressor. By knowing the mass flow, enthalpy of the refrigerant, etc. the cooling capacity and COP of the system can be calculated. During the evaluation period the average cooling capacity corrected for the ground heat gain and the brine pump power was 98.5 kW and the corresponding heat load based on the surface ice sheet conditions was estimated to 92.5 kW. This represents a deviation of 7% which is a measure of the modelling accuracy compared to the measurements.

  • 24.
    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.

  • 25.
    Sawalha, Samer
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Applied Thermodynamics and Refrigeration.
    Arias, 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, Applied Thermodynamics and Refrigeration.
    Forskning på KTH om livsmedelskyla: En översikt2014Other (Other (popular science, discussion, etc.))
  • 26.
    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.

  • 27.
    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.
    Rogstam, Jörgen
    Field measurements of supermarket refrigeration systems: Part I: Analysis of CO2 trans-critical refrigeration systems2015In: Applied Thermal Engineering, ISSN 1359-4311, E-ISSN 1873-5606, Vol. 87, p. 633-647Article in journal (Refereed)
    Abstract [en]

    This study investigates the refrigeration performance of three CO2 trans-critical solutions based on field measurements. The measurements are carried out in five supermarkets in Sweden. Using the field measurements, low and medium temperature level cooling capacities and COP's are calculated for ten-minute intervals, filtered and averaged to monthly values. The results indicate that the systems using trans-critical booster system with gas removal from the intermediate vessel have relatively the highest total COP. The reasons are higher evaporation temperatures, lower internal and external superheat and higher total efficiency of booster compressors. Another important factor is gas removal from the intermediate vessel which leads to higher COP of low temperature level. Comparing the older and newer installed systems, a trend in energy efficiency improvement has been seen. The study shows this improvement originates from both changes in the system design (e.g. two stage expansion) and components efficiency improvement (e.g. higher total efficiency of compressors - lower internal superheat and higher evaporation temperatures of cabinets).

  • 28.
    Sawalha, Samer
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Applied Thermodynamics and Refrigeration.
    Piscopiello, Salvatore
    KTH.
    Karampour, Mazyar
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Applied Thermodynamics and Refrigeration.
    Manickam, Louis
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Power Safety.
    Rogstam, Jörgen
    KTH.
    Field measurements of supermarket refrigeration systems. Part II: Analysis of HFC refrigeration systems and comparison to CO2 trans-critical2017In: Applied Thermal Engineering, ISSN 1359-4311, E-ISSN 1873-5606, Vol. 111, no 1, p. 170-182Article in journal (Refereed)
    Abstract [en]

    This part of the study investigates the performance of HFC refrigeration systems for supermarkets and compares the performance with alternative CO2 trans-critical solutions. The investigated HFC system solutions are typical in supermarkets in Sweden. The analysis in this study is based on field measurements which were carried out in three supermarkets in Sweden. The results are compared to the findings from Part I of this study where five CO2 trans-critical systems were analyzed. Using the field measurements, low and medium temperature level cooling demands and COP’s are calculated for five-minute intervals, filtered and averaged to monthly values. The different refrigeration systems are made comparable by looking at the different COP’s versus condensing temperatures. The field measurement analysis is combined with theoretical modelling where the annual energy use of the HFC and CO2 trans-critical refrigeration systems is calculated. Comparing the field measurement and modelling results of COP’s for HFC and CO2 systems, the new CO2 systems have higher total COP than HFC systems for outdoor temperatures lower than about 24 C. The modelling is used to calculate the annual energy use of HFC and new CO2 system in an average size supermarket in Stockholm, new CO2 systems use about 20% less energy than a typical HFC system. The detailed analysis done in this study (Part I and Part II) proves that new CO2 trans-critical refrigeration systems are more energy efficient solutions for supermarkets than typical HFC systems in Sweden.

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