Experimental investigation on the influence of internal heat exchanger in a transcritical CO2 heat pump water heater

Cao, Feng; Ye, Zuliang; Wang, Yikai

doi:10.1016/j.applthermaleng.2019.114855

Cited by 71 publications

(19 citation statements)

References 23 publications

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“…u,CCOP=(((∂CCOP/∂Q,evp)×u,Q,evp) 2 +((∂CCOP/∂P, cmr)×u,P,cmr) 2 ) 0.5 (8) where u,Q,evp is the uncertainty of the ,̇, which was calculated as: u,Q,evp=(((∂Q,evp/∂m,evp)×u,m,evp) 2 +((∂Q,evp/∂T,ev p,i)×u,T,evp,i) 2 +((∂Q,evp/∂T,evp,o)×u,T,evp,o) 2 ) 0.5 (9) where u,m,evp is the uncertainty of the m,evp, u,T,evp,i is the uncertainty of the T,evp,i, and u,T,evp,o is the uncertainty of the T,evp,o.…”

Section: Uncertainty Analysismentioning

confidence: 99%

“…These advantages motivate more studies about the CO2 heat pumps. For instance, an experimental study indicated that the coefficient of performance (COP) of the CO2 heat pump could be improved when the internal heat exchanger was applied [9]. The results presented in the Dai et al's study [10] indicated that the utilization of the direct dedicated mechanical subcooling technology could also improve the COP of the CO2 heat pump.…”

Section: Introductionmentioning

confidence: 99%

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Study of a water-source CO₂ heat pump for residential use: experimental discharge pressure control and performance analysis

Nord

Rekstad

et al. 2021

E3S Web Conf.

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The heat pumps with the refrigerant of carbon dioxide (CO2), i.e., CO2 heat pumps, have the merits of low price and environmentally friendliness in comparison with those with traditional refrigerants, e.g., hydrochlorofluorocarbons and chlorofluorocarbons. Current studies mainly focused on the air-source CO2 heat pumps, while investigations about the CO2 heat pumps gaining heat or cold energy from different mediums, e.g., water, are lacking. In addition, although few studies presented the investigations on the discharge pressure of the CO2 heat pumps (e.g., investigations of optimal discharge pressure), how to realize the effective discharge pressure control in the experimental conditions is still lacking. To remedy these knowledge gaps, this study presented an experimental investigation of a water-source CO2 heat pump for residential use. A PI controller was used to maintain the fixed discharge pressure by adjusting the opening of the electronic expansion valve. The dynamic performance of the CO2 heat pump in the typical discharge pressure of 7,200 to 8,400 kPa were analyzed. The results indicated that the method of using the PI controller to adjust the opening of the electronic expansion valve could effectively maintain the desired discharge pressure of the CO2 heat pump in the experimental conditions.

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Section: Uncertainty Analysismentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Study of a water-source CO₂ heat pump for residential use: experimental discharge pressure control and performance analysis

Nord

Rekstad

et al. 2021

E3S Web Conf.

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“…In the past few years much, scientific attention has been paid to the use of vapor compression cycles with and without internal heat exchangers [2][3][4][5]. Research works have dealt with the comparison of cooling capacity amounts, power consumption of the system and COP parameters when operating at various evaporation and condenser temperatures implementing R1234yf and R1234ze(E) as possible alternatives for R134a [6][7][8][9].…”

Section: Introductionmentioning

confidence: 99%

Comparative Analysis of Heat Pump System with IHX Using R1234yf and R134a

Sánta

2021

Period. Polytech. Mech. Eng.

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This research presents an energy performance analysis of the heat pump system with internal heat exchanger (IHX). The mathematical model of the heat pump outlined in this paper has been created by the author, it is steady-state with lumped parameters. The experimental validation of the model has been carried out using R1234yf and R134a as refrigerant. The aim of this work is to compare the energy performance in a wide range of operating conditions of a monitored heat pump system using both refrigerants. Finally, the heating capacity for R1234yf was lower from 0.63 % to 7.54 % compared with R134a, while the compressor power was similar from 0.12 % to 3.51 %. The COP values of R1234yf were lower than those obtained of R134a, ranging from 1.39 % to 4.22 %.

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“…In this type of cycle, only one expansion valve is needed. Among the authors who have studied the cycle with IHX, can be found the works by Lorentzen [32], Nekså et al [35], Liao et al [51], Aprea & Maiorino [52], Chen and Gu [53], Pérez-García et al [54], Minetto et al [42], Shao et al [55] and Cao et al [56]. On the other hand, other authors have presented the cycle without IHX, such as [54,57].…”

Section: Configurations Used In Co2 Heat Pumpsmentioning

confidence: 99%

“…Considering the most common compressor type, semi-hermetic, from the study about the development of a semi-hermetic CO2 compressor by Nekså [77] in the 20 th International Congress of Refrigeration in 2002, to the most recent studies [56,65,78,79,80,81,82], in CO2 applications, it is widely the most used type of compressor.…”

Section: Most Common Types Of Compressors For Co2 Applicationsmentioning

confidence: 99%

Experimental and numerical study of a water-to-water heat pump working with CO2

Cuevas¹,

Francisco²

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In this thesis, a one-stage transcritical CO2 water-to-water heat pump is numerically and experimentally analyzed in the production of hot water for the applications of space heating and domestic hot water (DHW). Different configurations commonly used in the market are studied and compared for the same water temperatures at the heat sink (evaporator) and heat source (condenser). From now on, since in CO2 transcritical cycles does not exist phase change, the condenser is called gas cooler.

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Experimental investigation on the influence of internal heat exchanger in a transcritical CO2 heat pump water heater

Cited by 71 publications

References 23 publications

Study of a water-source CO₂ heat pump for residential use: experimental discharge pressure control and performance analysis

Study of a water-source CO₂ heat pump for residential use: experimental discharge pressure control and performance analysis

Comparative Analysis of Heat Pump System with IHX Using R1234yf and R134a

Experimental and numerical study of a water-to-water heat pump working with CO2

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Experimental investigation on the influence of internal heat exchanger in a transcritical CO2 heat pump water heater

Cited by 71 publications

References 23 publications

Study of a water-source CO2 heat pump for residential use: experimental discharge pressure control and performance analysis

Study of a water-source CO2 heat pump for residential use: experimental discharge pressure control and performance analysis

Comparative Analysis of Heat Pump System with IHX Using R1234yf and R134a

Experimental and numerical study of a water-to-water heat pump working with CO2

Contact Info

Product

Resources

About

Study of a water-source CO₂ heat pump for residential use: experimental discharge pressure control and performance analysis

Study of a water-source CO₂ heat pump for residential use: experimental discharge pressure control and performance analysis