Field measurements of supermarket refrigeration systems. Part II: Analysis of HFC refrigeration systems and comparison to CO2 trans-critical

Sawalha, Samer; Piscopiello, Salvatore; Karampour, Mazyar; Manickam, Louis; Rogstam, Jörgen

doi:10.1016/j.applthermaleng.2016.09.073

Cited by 61 publications

(34 citation statements)

References 9 publications

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“…As of January 2016, more than 7000 supermarkets in the world have installed CO 2 trans-critical booster system, out of which 5500 in Europe (Shecco, 2016). CO 2 trans-critical systems have similar or higher cooling COP compared to conventional hydrofluorocarbon (HFC) system at ambient temperatures lower than about 25°C (Sawalha et al, 2017). This is why they have been popular in new installations in the relatively cold climate of northern Europe.…”

Section: Abbreviationsmentioning

confidence: 97%

“…On the high pressure side, the heat from MT and LT condensers are rejected to the ambient by indirect secondary fluid cycles connected to a dry cooler. The secondary fluid circulation pumps power is assumed to be 20% of the MT compressor electricity use, based on field measurements (Sawalha et al, 2017). The heating and AC systems in S4 solution are similar to S3.…”

Section: Annual Electricity Use Comparison Studymentioning

confidence: 99%

“…Most of the inputs to the models are adapted from field measurements analysis presented in this paper and a recent study by Sawalha et al (2017). However, larger cooling and heating loads, compared to section 4.2, are used to represent better a medium sized supermarket demands.…”

Section: Annual Electricity Use Comparison Studymentioning

confidence: 99%

“…The method applied in this study is to find the compressors mass flow rates based on volumetric efficiencies and swept volume flow rates of compressors obtained from the manufacturer data, the method is explained by Sawalha et al (2017).…”

Section: Compressors' Electricity Use Refrigeration Heating and Airmentioning

confidence: 99%

“…This solution is considered as the reference system in this energy use comparison study since its refrigeration system is the most conventional system solution in many European supermarkets.  System solution 4 (S4) -only for Stockholm: standard conventional HFC refrigeration system in Sweden is an indirect R404A system as presented by Sawalha et al (2017) and shown in Figure 7. This refrigeration system is composed of two R404A loops; low temperature (LT) loop in the freezers is a DX R404A unit while medium temperature (MT) loop consists of an indirect secondary fluid (for example, propylene glycol or ethylene glycol) cycle connecting the MT cabinets to an R404A refrigeration unit.…”

Section: Annual Electricity Use Comparison Studymentioning

confidence: 99%

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Energy efficiency evaluation of integrated CO 2 trans-critical system in supermarkets: A field measurements and modelling analysis

Karampour

Sawalha

2017

International Journal of Refrigeration

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This paper investigates energy efficiency of an integrated CO 2 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 CO 2 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.

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Section: Abbreviationsmentioning

confidence: 97%

Section: Annual Electricity Use Comparison Studymentioning

confidence: 99%

Section: Annual Electricity Use Comparison Studymentioning

confidence: 99%

Section: Compressors' Electricity Use Refrigeration Heating and Airmentioning

confidence: 99%

Section: Annual Electricity Use Comparison Studymentioning

confidence: 99%

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Energy efficiency evaluation of integrated CO 2 trans-critical system in supermarkets: A field measurements and modelling analysis

Karampour

Sawalha

2017

International Journal of Refrigeration

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Thermodynamic performance evaluation of the CO ₂ parallel compression supermarket refrigeration system with a subcooler

et al. 2020

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Summary Commercial refrigeration systems in supermarkets are intensive users of energy and CO2 is recognized as the most promising refrigerant such systems. The CO2 parallel compression system has been considered in medium‐ and low‐temperature supermarket refrigeration systems, with auxiliary compressors to enhance system performance. This study is intended to investigate the effects of adding a subcooler in a CO2 trans‐critical supermarket refrigeration system with parallel compression (SPR system). Mathematical models based on mass and energy conservation are built. Optimization is performed for the gas cooler pressure and the receiver pressure for maximizing the coefficient of performance (COP). The performance of the parallel compression system with a subcooler is analyzed and compared to a baseline parallel compression system in different cities of China. A 6.8% average promotion at least in seasonal energy efficiency ratio (SEER) is predicted, and the energy consumption of the whole system decreases 7.1% totally in Haikou. Gas cooler, taking up 63.3% of the total exergy destruction rate, is the key component to increase efficiency through exergy analysis.

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Experimental comparison between R134a/R744 and R438A/R744 (drop‐in) cascade refrigeration systems based on energy consumption and greenhouse gases emissions

Queiroz

Ojeda

Amjad

et al. 2021

Energy Science & Engineering

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This experimental study evaluates the energy performance and climatic changes of a cascade cooling system operating with the R134a/R744 pairs (cooling capacity of 4.5-6 kW) and R438A/R744. In both cases, the low-temperature refrigerant, R744, operated under subcritical conditions. The experimental apparatus basically consists of two vapor-compression cycles coupled by a plate cascade condenser. Two operational variables, from R744 cycle, were controlled: the degree-of-superheat and the compressor frequency. The experiment was initially assembled to pair R134a/R744. Subsequently, the R134a refrigerant charge in the high-temperature cycle was replaced by R438A, on a drop-in basis. The two systems, R134a/R744 and R438A/R744, were compared for similar cooling capacities and cold chamber air temperatures. Results showed that the energy consumption of the high-temperature compressor, operating with R438A, was higher than R134a for all tests. As a result, the COP values for R438A/R744 were 30% lower than those for R134a/R744. The greenhouse gases emissions of the two systems were evaluated using the total equivalent warming impact factor, TEWI, whose value for the R438A/R744 pair was approximately 29.5% higher, compared with R134a/R744. Since R438A was originally designed to substitute R22, a few comparative tests were carried out with the latter, always with R744 as the low-temperature cycle working fluid.

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Field measurements of supermarket refrigeration systems. Part II: Analysis of HFC refrigeration systems and comparison to CO2 trans-critical

Cited by 61 publications

References 9 publications

Energy efficiency evaluation of integrated CO 2 trans-critical system in supermarkets: A field measurements and modelling analysis

Energy efficiency evaluation of integrated CO 2 trans-critical system in supermarkets: A field measurements and modelling analysis

Thermodynamic performance evaluation of the CO ₂ parallel compression supermarket refrigeration system with a subcooler

Experimental comparison between R134a/R744 and R438A/R744 (drop‐in) cascade refrigeration systems based on energy consumption and greenhouse gases emissions

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Field measurements of supermarket refrigeration systems. Part II: Analysis of HFC refrigeration systems and comparison to CO2 trans-critical

Cited by 61 publications

References 9 publications

Energy efficiency evaluation of integrated CO 2 trans-critical system in supermarkets: A field measurements and modelling analysis

Energy efficiency evaluation of integrated CO 2 trans-critical system in supermarkets: A field measurements and modelling analysis

Thermodynamic performance evaluation of the CO 2 parallel compression supermarket refrigeration system with a subcooler

Experimental comparison between R134a/R744 and R438A/R744 (drop‐in) cascade refrigeration systems based on energy consumption and greenhouse gases emissions

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Thermodynamic performance evaluation of the CO ₂ parallel compression supermarket refrigeration system with a subcooler