Modeling and Simulation of Transcritical CO2 Heat Pump System with Throttle Valve

Yang, Jiani; Ma, Yixin; Li, Min Xia; Tian, Hua

doi:10.1109/icece.2010.324

Cited by 3 publications

(5 citation statements)

References 6 publications

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“…Fig. 8 illustrates the drastic decrease in heat load for increasing water inlet temperature, which supports the findings by Yang [9]. The trendline feature in Excel is used to obtain curve fits for each water flow rate.…”

Section: Recirculation With Once-through Hx and Internal Heat Exchsupporting

confidence: 81%

“…Similar experimental investigations on transcritical CO 2 heat pump systems have proven that overall COP drops quickly as the inlet water temperature to the gas cooler increases [9]. This relationship can be explained by realizing that an increasing water inlet temperature simply means there is less thermal energy that the water is able to accept from the CO 2 .…”

Section: A Recirculation-onlymentioning

confidence: 62%

“…Therefore, reducing the inlet water temperature to the gas cooler can result in significant improvements to overall heat pump performance [9]. To take advantage of this, the second design option considered incorporates a bypass valve into the regular recirculation loop described in the first configuration.…”

Section: B Recirculation With Bypass Valvementioning

confidence: 99%

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Thermal energy from transcritical CO<inf>2</inf> heat pumps for small marine applications

McLean

Pope

Muzychka

2014

2014 Oceans - St. John's

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Heat pumps are a more efficient method to heat water compared to conventional electrical heating systems. However, the harmful environmental effects of traditional CFC and HCFC refrigerants require more sustainable alternatives to be adopted. In marine applications, leaked HCFCs can cause substantial harm to sensitive coastal ecology and are powerful greenhouse gases. Standard CO 2 (R744 when used as a refrigerant) is a promising replacement for HCFCs due to its low global warming and ozone depletion potential. This paper investigates adapting the traditional ground loop of a geothermal heat pump to a marine loop for use with seawater or coastal applications. New analytical results on the use of thermal energy from marine water for domestic water heating with a transcritical CO 2 heat pump are presented in this paper. Substantial research has recently been performed on transcritical CO 2 heat pump cycles, including cycle enhancements and optimization techniques. However, the research has been primarily focused on traditional heat pump configurations, with ambient air usually being the heat source. Geothermal temperatures vary on average between 8°C to 12°C throughout the year. A large body of water in this temperature range can provide a consistent source of thermal energy and thus effectively replace the ground source used in typical geothermal heat pumps.

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Section: Recirculation With Once-through Hx and Internal Heat Exchsupporting

confidence: 81%

Section: A Recirculation-onlymentioning

confidence: 62%

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Thermal energy from transcritical CO<inf>2</inf> heat pumps for small marine applications

McLean

Pope

Muzychka

2014

2014 Oceans - St. John's

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“…The application of natural refrigerant CO 2 is of great significance to reduce the greenhouse effect and ozone depletion. Trancritical CO 2 refrigeration cycle is presently an important aspect of natural refrigerant alternatives research [1][2][3]. CO 2 as a refrigerant, has its unique advantages, but the COP of the transcritical system is not high because of their lower critical temperature (31℃).…”

Section: Introductionmentioning

confidence: 99%

Vortex Tube Expansion Two-Stage Transcritical CO2 Refrigeration Cycle

Liu

Jin

2012

AMR

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Use of vortex tube as an expansion device in transcritical CO2 cycle could reduce the throttle loss and improve the coefficient of performance. In this paper, a vortex tube expansion two-stage transcritical CO2 refrigeration cycle(VTTC) is established and compared to that of the two-stage transcritical CO2 refrigeration cycle with throttle valve(TVTC). Thermodynamic analysis results indicate that there is also an optimum heat rejection pressure for the vortex tube cycle, and the COP improvement is 2.4%~16.3% at given conditions. Decrease in evaporation temperature or increase in gas-cooler outlet temperature decrease the COP, but the COP improvement will increase. The effect of cold mass fraction on the COP is negligible, but the COP improvement will increase fast with the increase of cold mass fraction.

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“…In recent years, several researchers [3][4][5][6][7] have investigated the transcritical CO 2 system. But the COP of the transcritical system is not high because of their lower critical temperature (31˚C).…”

Section: Introductionmentioning

confidence: 99%

Experimental Investigation on Transcritical CO2 Refrigeration System

Liu

Shen

Jin

2012

AMR

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The application of natural refrigerant CO2 is of great significance to reduce the greenhouse effect and ozone depletion. Transcritical CO2 refrigeration cycle is presently an important aspect of natural refrigerant alternatives research. In this paper, the transcritical CO2 refrigeration cycle system is experimentally studied, effect on performance of heat rejection pressure, gas-cooler outlet temperature and evaporation temperature is analyzed. The experimental results show that there is an optimum high pressure to achieve the maximum COP, the evaporation temperature and gas-cooler exit temperature have great impact on the COP. Increase of gas-cooler outlet temperature led to a rapid increase in the optimal high pressure, but effect of evaporation temperature is not obvious. So in order to obtain the optimum performance, the influence of heat rejection pressure, evaporating temperature and gas-cooler outlet temperature should be considered during the designing and operating CO2 refrigeration cycle system.

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Modeling and Simulation of Transcritical CO₂ Heat Pump System with Throttle Valve

Cited by 3 publications

References 6 publications

Thermal energy from transcritical CO<inf>2</inf> heat pumps for small marine applications

Thermal energy from transcritical CO<inf>2</inf> heat pumps for small marine applications

Vortex Tube Expansion Two-Stage Transcritical CO<sub>2</sub> Refrigeration Cycle

Experimental Investigation on Transcritical CO<sub>2</sub> Refrigeration System

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