Thermodynamic analysis of a novel heat pump water heater with two-stage heating for a great rise of water temperature

2015 ◽  
Vol 91 ◽  
pp. 97-104 ◽  
Author(s):  
Jianhua Wu ◽  
Jie Lin
2011 ◽  
Vol 393-395 ◽  
pp. 601-603
Author(s):  
Ai Guo Jiang ◽  
Xiao Zhong Wang

Solar water heater cannot supply hot water in cloudy and raining days alone. It in combination with air source heat pump water heater (ASHPWH) is a good choice. The performance of the two kinds of water heater is affected by the water temperature. It is important that the ASHPWH operate at a right temperature of the water. A solar water heater with 4m2 flat-plate collector assisted by a 1.5kW ASHPWH is studied in this paper. The results show that both the collector efficiency of the solar water heater and the COP of the ASHPWH system decreases as the water temperature increases. The highest and lowest collector efficiency of the solar water heater are 54.4% and 45.6% respectively. The COP of the ASHPWH system ranges from 6.48 to 2.61 as the water temperature increases. Operating sequences of these two kinds of water heater affect solar energy utilization ratio and the power input of the ASHPWH system.


2013 ◽  
Vol 805-806 ◽  
pp. 637-644
Author(s):  
Jun Fan ◽  
Feng Zhong Sun ◽  
Ming Gao

Heat recovery of low pressure steam in steam condenser of thermal power plant was attractive because of its great economy and environmental value. This paper reported the experimental investigation results on the application of a heat pump water heater (HPWH) using low pressure steam in steam condenser as heat source. The working principles and features of the prototype heat pump were introduced. The effects of various parameters, including water flow rate and inlet temperature of heat pump condenser were investigated. Influence of vacuum pump on HPWH was also discussed. Results show that performance of HPWH is governed strongly by the change of water flow rate and inlet water temperature of heat pump condenser and vacuum pump. Maximum outlet water temperature of the test HPWH is 65°C and the maximum coefficient of performance (COP) is 4.5.


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