Optimal discharge pressure in transcritical CO2 heat pump water heater with internal heat exchanger based on pinch point analysis

2020 ◽  
Vol 118 ◽  
pp. 12-20
Author(s):  
Zuliang Ye ◽  
Yikai Wang ◽  
Yulong Song ◽  
Xiang Yin ◽  
Feng Cao
Keyword(s):  
Heat Exchanger ◽  
Heat Pump ◽  
Internal Heat ◽  
Water Heater ◽  
Pinch Point ◽  
Internal Heat Exchanger ◽  
Heat Pump Water Heater ◽  
Point Analysis ◽  
Discharge Pressure

scholarly journals Numerical study on the influence of internal heat exchanger in transcritical CO2 heat pumps under optimal pressure conditions

2021 ◽  
Vol 2116 (1) ◽  
pp. 012098
Author(s):  
F Illán-Gómez ◽  
J R García-Cascales ◽  
F J Sánchez-Velasco ◽  
V Sena-Cuevas ◽  
R Otón-Martínez
Keyword(s):  
Heat Exchanger ◽  
Heat Pump ◽  
Strong Influence ◽  
Numerical Study ◽  
Internal Heat ◽  
Heat Pumps ◽  
Operating Conditions ◽  
Water Heater ◽  
Internal Heat Exchanger ◽  
Heat Pump Water Heater

Abstract This paper presents a numerical study on the influence of internal heat exchanger (IHX) exchanging surface in the performance of a transcritical CO2 heat pump water heater at different operating conditions. Five different IHX geometries and four different evaporation temperatures have been studied with water temperature ranging from 10 °C to 60 °C at the gas cooler inlet. The results show a strong influence of IHX characteristics on system’s performance.

scholarly journals The Influence of Internal Heat Exchanger on the Performance of Transcritical CO2 Water Source Heat Pump Water Heater

Energies ◽  
2020 ◽  
Vol 13 (7) ◽  
pp. 1787
Author(s):  
Fan Feng ◽  
Ze Zhang ◽  
Xiufang Liu ◽  
Changhai Liu ◽  
Yu Hou
Keyword(s):  
Heat Exchanger ◽  
Heat Pump ◽  
Internal Heat ◽  
Water Source ◽  
Hot Water ◽  
Operational Performance ◽  
Water Heater ◽  
Source Temperature ◽  
Internal Heat Exchanger ◽  
Heat Pump Water Heater

The characteristics of the transcritical CO2 heat pump water heater (HPWH) system are; a lower inlet hot water temperature (Ti-hw) (sometimes this is lower than the water source temperature), and an outlet gas cooler temperature (To-gc) which is affected by the Ti-hw and often lower than the critical temperature. In order to study the effects of the internal heat exchanger (IHX) on the operational performance of the transcritical CO2 HPWH when To-gc is low, a transcritical CO2 water source HPWH experiment platform is established to conduct experimental research and comparative analysis on the operational performance of the transcritical CO2 water source HPWH, with or without IHX. It is found that, if only the coefficient of performance (COP) and heating at the optimal exhaust pressure of the transcritical CO2 water source HPWH were considered, COP and the heating of the non-IHX system would be slightly higher than those of the IHX system at the lower hot water flow and water source temperature, and this increase was not obvious. At the higher hot water flow rate and water source temperature, COP and the heating of the non-IHX system were also higher than those of the IHX system, and the increase was obvious. The experiment results showed that, near the optimal exhaust pressure, the variation range of COP and heating of the IHX system is relatively small, and the system has a relatively high stability.

Water Mass Flow and Air Relative Humidity on Performance of Air - Source Heat Pump Water Heater

2015 ◽  
Vol 1092-1093 ◽  
pp. 127-130
Author(s):  
Zhi Jiang Wu ◽  
Yan Sheng Xu
Keyword(s):  
Heat Transfer ◽  
Relative Humidity ◽  
Heat Pump ◽  
Mass Flow ◽  
Water Mass ◽  
Water Heater ◽  
Air Source Heat Pump ◽  
Heat Pump Water Heater ◽  
Condenser Temperature ◽  
Discharge Pressure

The water mass flow and air relative humidity on the performance of air-source heat pump water heater was discussed in this paper. The results show that the energy efficiency of heat pump water heater is improved by correct the water mass flow and discharge pressure can be reduced, the value of the condenser temperature difference between the import and export of water also can be reduced. Increasing the air relative humidity, the more condensated water on evaporator surface effective, the greater the wetting area. In addition, the heat transfer of latent heat can be increased by the growth of air side and refrigerant side heat transfer coefficient.

Performance Assessments of Organic Rankine Cycle With Internal Heat Exchanger Based on Exergetic Approach

2018 ◽  
Vol 140 (10) ◽  
Author(s):  
Nurettin Yamankaradeniz ◽  
Ali Husnu Bademlioglu ◽  
Omer Kaynakli
Keyword(s):  
Heat Exchanger ◽  
Organic Rankine Cycle ◽  
Internal Heat ◽  
Rankine Cycle ◽  
Performance Assessments ◽  
Evaporator Temperature ◽  
Pinch Point ◽  
Internal Heat Exchanger ◽  
Energy And Exergy ◽  
Energy And Exergy Analysis

This study makes energy and exergy analysis of a sample organic Rankine cycle (ORC) with a heat exchanger which produces energy via a geothermal source with a temperature of 140 °C. R600a is preferred as refrigerant to be used in the cycle. The changes in exergy destructions (of irreversibility) and exergy efficiencies in each cycle element are calculated in the analyses made based on the effectiveness of heat exchanger used in cycle and evaporator temperature changing between 60 and 120 °C for fixed pinch point temperature differences in evaporator and condenser. Parameters showing system performance are assessed via second law approach. Effectiveness of heat exchanger and temperature of evaporator are taken into consideration within the scope of this study, and energy and exergy efficiencies of cycle are enhanced maximum 6.87% and 6.21% respectively. Similarly, exergy efficiencies of evaporator, heat exchanger, and condenser are increased 4%, 82%, and 1.57%, respectively, depending on the effectiveness of heat exchanger and temperature of evaporator.

scholarly journals Experimental study on vapor injection air source heat pump with internal heat exchanger for electric bus

2019 ◽  
Vol 158 ◽  
pp. 4147-4153 ◽  
Author(s):  
Xinxin Han ◽  
Huiming Zou ◽  
Hongbo Xu ◽  
Changqing Tian ◽  
Wei Kang
Keyword(s):  
Experimental Study ◽  
Heat Exchanger ◽  
Heat Pump ◽  
Internal Heat ◽  
Air Source Heat Pump ◽  
Internal Heat Exchanger ◽  
Electric Bus ◽  
Vapor Injection
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