Efficiencies of transcritical CO2 cycles with and without an expansion turbine

Robinson, D. M.; Groll, Eckhard A.

doi:10.1016/s0140-7007(98)00024-3

Cited by 235 publications

(98 citation statements)

References 3 publications

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“…It must be pointed out that Brown et al (2002) suggested this formula for pressure ratios higher than 2. However, applying this correlation for lower pressure ratio values gives results which are close to the ones generated by the correlations of Robinson and Groll (1998) and Liao et al (2000). The correlation presented by Liao et al (2000) is a curve fit of experimental data of a CO 2 compressor and has been used in calculations for pressure ratios close to 1.5.…”

Section: Compressorssupporting

confidence: 60%

“…(2) which is a curve fit by Brown et al (2002) for CO 2 compressor in mobile air conditioning system. This correlation has been compared by Chen and Gu (2005) to two other compressor curve fits, Robinson and Groll's (1998) and Liao et al's (2000), and was adapted as a good approximation for the real performance of an open type CO 2 compressor.…”

Section: Compressorsmentioning

confidence: 99%

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Theoretical evaluation of trans-critical CO2 systems in supermarket refrigeration. Part I: Modeling, simulation and optimization of two system solutions

Sawalha

2008

International Journal of Refrigeration

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Section: Compressorssupporting

confidence: 60%

Section: Compressorsmentioning

confidence: 99%

Theoretical evaluation of trans-critical CO2 systems in supermarket refrigeration. Part I: Modeling, simulation and optimization of two system solutions

Sawalha

2008

International Journal of Refrigeration

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“…A detailed parametric analysis (Robinson and Groll 1998) revealed that COP can increase if the expander efficiency is 30 %, but decreases when the expander isoentropic efficiency is 60 %. Heidelck and Kruse (2000) discussed a new expander design based on a modified, reciprocating machine.…”

Section: Introductionmentioning

confidence: 99%

An experimental study on charge optimization of a trans-critical CO2 cycle

Aprea

Greco

Maiorino

2014

Int. J. Environ. Sci. Technol.

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The phasing out of hydrochlorofluorocarbon and chlorofluorocarbon fluids and further environmental problems arising from new, synthetic working fluids stimulate a continuously rising interest on natural candidates. The nontoxic and nonflammable CO 2 impacts neither on ozone depletion nor on global warming if leaked to the atmosphere. The critical temperature of CO 2 (31.1°C) is almost ambient and, therefore, it undergoes a transcritical refrigeration cycle. In cooling mode operation, a trans-critical CO 2 system, as compared to conventional airconditioners, has a lower performance which, contrary to conventional systems, strongly depends on the refrigerant charge. In this paper, the performance of the trans-critical system was evaluated experimentally under different refrigerant charge amounts. The influence of charge on coefficient of performance (COP), cooling capacity, compression ratio, suction line superheat was analyzed in detail. The experimental results indicate that the COP of the trans-critical cycle attains a maximum at optimal refrigerant charge. By varying the charge the cooling capacity attains a maximum, as well, that corresponds to the optimal charge. In order to understand the effect of refrigerant charge on the performance of each device of the plant, an exergetic analysis based on the experimental data was carried out. The analysis shows that the exergy flow destroyed in the compressor is one of the major causes of overall exergy destruction. At the optimal refrigerant charge, the compression losses attain a minimum.

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“…[13] and others [14] in air conditioning, Nekså [15,16] in heat pumps where the results are quite good, and some others that are developing new cycle configurations [17,18] and new elements [19,20]. But what is common to all transcritical carbon dioxide applications is the existence of an optimal pressure in the gas-cooler at which the maximum efficiency of the refrigerating cycle is achieved.…”

Section: Introductionmentioning

confidence: 99%