scholarly journals Investigation on the efficiency degradation characterization of low ambient temperature air source heat pump under partial load operation

2021 ◽  
Author(s):  
Zhaowei Xu ◽  
Hao Li ◽  
Wei Xu ◽  
Shuangquan Shao ◽  
Zhichao Wang ◽  
...  
Keyword(s):  
Ambient Temperature ◽  
Heat Pump ◽  
Air Source Heat Pump ◽  
Partial Load ◽  
Low Ambient Temperature

Experimental Investigation and Numerical Simulation for High Temperature Air Source Heat Pump with New Mixed-Refrigerant

2014 ◽  
Vol 541-542 ◽  
pp. 752-755
Author(s):  
Jun Yang ◽  
Guo Zhong Ding ◽  
Xiao Yan Zhang ◽  
Shui Ming Shu ◽  
Jun Yi Tan
Keyword(s):  
Numerical Simulation ◽  
Experimental Investigation ◽  
High Temperature ◽  
Ambient Temperature ◽  
Water Temperature ◽  
Heat Pump ◽  
Air Source Heat Pump ◽  
Discharge Temperature ◽  
Heating Capacity ◽  
Theory And Experiments

Studies on air source heat pump (ASHP) transfer to high temperature, the performance of air source heat pump greatly depends on the ambient temperature. Aimed at the prototype aeroplane of high temperature air source heat pump, New mixed-refrigerant M-R was adopted, and a simulation was made under a standard conditions with Aspen Plus software. And the results was validated by the experiments. The results showed that a well trend between theory and experiments. In addition, experimental investigation of high temperature air source heat pump were carried out at different conditions. The COP was 1.15, the discharge temperature of compressor was 108.6°Cwhen the outlet water temperature was 85.1°C. The heating capacity is superior. This achieved a leading level at home and abroad.

Performance optimization of an air source heat pump water heater using mathematical modelling

2015 ◽  
Vol 26 (1) ◽  
pp. 96-105 ◽  
Author(s):  
Stephen Tangwe ◽  
Michael Simon ◽  
Edson L. Meyer ◽  
Sampson Mwampheli ◽  
Golden Makaka
Keyword(s):  
Ambient Temperature ◽  
Heat Pump ◽  
Performance Optimization ◽  
Rate Of Change ◽  
Hot Water ◽  
Coefficient Of Performance ◽  
Water Tank ◽  
Water Heater ◽  
Conservation Of Energy ◽  
Air Source Heat Pump

In South Africa, there is an ongoing constraint on the electricity supply at the national grid to meet the demand. Eskom is implementing various measures such as the Integrated Demand Management and the promotion and encouragement of the use of energy efficient devices like an Air Source Heat pump (ASHP) water heater to replace the high electrical energy consuming conventional geysers for sanitary hot water production. The ASHP water heater market is fast gaining maturity. A critical mathematical model can lead to performance optimization of the systems that will further result in the conservation of energy and significant reduction in global warming potential. The ASHP water heater comprises of an ASHP unit and a hot water storage tank. In this study, a data acquisition system (DAS) was designed and built which monitored the energy used by the geyser and the whole building, the temperature at the evaporator, condenser, tank outlet hot water, tank inlet cold water, the ambient temperature and relative humidity in the vicinity of the ASHP evaporator. It is also worthy to mention that the DAS also included to a flow meter and two additional temperature sensors that measured the volume of water heated and inlet and outlet water temperature of the ASHP. This work focused on using the mathematical equation for the Coefficient of Performance (COP) of an ideal Carnot’s heat pump (CHP) water heater to develop basic computation in M-file of MATLAB software in order to model the system based on two reservoir temperatures: evaporator temperatures (Tevp) of 0°C to 40°C (approximated to ambient temperature, Ta) and condenser temperatures (TCon) set at 50°C, 55°C and 60°C (approximated to the hot water set temperature of 50°C, 55°C and 60°C) respectively. Finally, an analytical comparison of a CHP water heater to the practical ASHP water heater was conducted on a hot water set point temperature of 55°C. From the modelling results, it can be deduced that at 0°C Tevp, the COP was 5.96 and 2.63 for CHP and ASHP water heater respectively, at a hot water set temperature of 55°C. Above 20°C Tevp, the rate of change of COP increased exponentially for the ideal CHP system, but was constant at 0.01/°C for the practically modelled ASHP water heater.

scholarly journals Experimental study on R1234yf heat pump at low ambient temperature and comparison with other refrigerants

2019 ◽  
Vol 23 (6 Part B) ◽  
pp. 3877-3886
Author(s):  
Shuxue Xu ◽  
Jianhui Niu ◽  
Guoyuan Ma
Keyword(s):  
Ambient Temperature ◽  
Heat Pump ◽  
Power Input ◽  
Coefficient Of Performance ◽  
Injection System ◽  
Pump System ◽  
Heat Pump System ◽  
Performance Improvements ◽  
Vapor Injection ◽  
Low Ambient Temperature

In this paper, an integrated vapor injection compression heat pump system using R1234yf, R32, R410A, R22, and R134a as working fluids was developed, and their heating performances under low ambient temperature were quantitatively evaluated. An experimental bench was built to test the system?s working performance. The condensing temperature, evaporating temperature, power input, and other variables were analyzed to evaluate the system?s heating capability and energy efficiency. Test results showed that the R1234yf system can run at the evaporating temperature of ?20 ?C, but its heating coefficient of performance was 5% lower than R134a. The R1234yf vapor injection system provided very significant performance improvements for heating performance compared with no vapor injection: the heating capacity and heating coefficient of performance can be improved by 14.3% and 11.7%, respectively.

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