Experimental Study on the Performance of Water Source Trans-Critical CO2 Heat Pump Water Heater
Experimental Study on the Performance of Water Source Trans-Critical CO2 Heat Pump Water Heater
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DOI：
10.3390/en10060810
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发表时间：
2017-06
期刊：
影响因子：
3.2
通讯作者：
X. Liu;Changhai Liu;Ze Zhang;Liang Chen;Yu Hou
中科院分区：
文献类型：
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作者：
X. Liu;Changhai Liu;Ze Zhang;Liang Chen;Yu Hou
在水源热泵热水器试验台上，研究了排气压力对低气冷器出口温度跨临界CO2热泵性能的影响。研究了跨临界CO2热泵在不同外部运行条件下的最佳排气压力。当自来水温度较低时，超临界区域s型等温线特性对最佳排放压力的产生影响不大；而CO2的质量流量、吸气压力和冷却器出口温度对最佳排气压力的出现起着重要的决定作用。在最优排放压力下，COP达到峰值；然而，相应的供热能力仍然低于其最大值，这是由于排放压力略高于最佳排放压力。降低自来水流量或提高水源温度均可提高最优排放压力。COP正依赖于自来水流量和水源温度。此外，自来水流量对最大供热能力的影响可以忽略不计，而提高水源温度可以大大提高供热能力。
The effect of the discharge pressure on the performance of the trans-critical CO2 heat pump with a low gas-cooler outlet temperature is experimentally investigated on a test rig of water source heat-pump water heater. The optimal discharge pressure of the trans-critical CO2 heat pump is investigated under different external operation conditions. When the tap-water temperature is low, the characteristic of the S-shape isotherm at the supercritical region has little effect on the occurrence of the optimal discharge pressure; while the mass flow rate of CO2, the suction pressure and the gas-cooler outlet temperature play a significant role in determining the emergence of the optimal discharge pressure. At the optimal discharge pressure, the COP reaches the peak; however, the corresponding heating capacity is still lower than its maximum, which is reached as the discharge pressure is slightly above the optimal discharge pressure. Reducing the tap-water flowrate or increasing the water-source temperature can increase the optimal discharge pressure. The COP is positively dependent on both the tap-water flowrate and the water-source temperature. In addition, the tap-water flowrate has a negligible influence on the maximum heating capacity while increasing the water-source temperature can greatly enhance the heating capacity.