双热源热泵制热水与供暖性能诊断

Diagnosis on Water Heater and Heating Performance of Dual Heat Source Heat Pump System

通过对3种热泵供暖性能系数(COP)比较可知,太阳能热泵供暖COP值比空气源热泵高。运用试验分析和理论计算发现压缩机电效率随压缩机压缩比的增加呈线性下降规律,并直接导致双热源热泵系统制热水性能系数(COP)偏低,当热水温度超过时,COP值甚至<1。通过对系统供暖试验数据的拟合得到2个表征双热源热泵系统供暖性能优劣的数学模型,试验和模型都显示出当蒸发器进口水温为28℃左右时,系统供暖COP值最大,而当蒸发器进口水温偏离该值时,COP值都会下降。对双热源热泵系统制热水和供暖的不可逆程度分析发现当压缩机压缩比ε=3.4时,系统运行更接近可逆过程,即系统运行最佳,压缩比偏离该值会导致系统不可逆损失增加。

Through comparing coefficient of performance （COP） of three kinds of heat pump heating systems, the COP of solar heat pump heating system was 13. 7 percent higher than that of air source heat pump heating system. Applying experimental analysis and theoretical reck- on, the compressor electric efficiency submitted linearity drop law along with compression ratio raise, which directly resulted in coefficient of water heater performance（COP） of Dual Heat Source Heat Pump System lower. When the temperature of hot water exceeded over, COP value is even less than 1.0. Through fitting heating experimental data, two mathematic models were obtained which embodied heating performance advantage and disadvantage. Experiment and models indicated that when the inlet water temperature of evaporator was about 28 ℃, the heating COP was the maximum and while the inlet water temperature of evaporator was lower or higher than that value, COP would fall. Through nonreversible analysis of water heater and heating, it was found that when compressor compression ratio ε was 3.4, the system still ran near reversible process, that meant system run best. The departure of com-pression ratio to that value would result in non-reversible loss raise.