风机转速对CO_(2)空气源热泵热水器性能影响的试验研究

Experimental study on the effect of fan speed on performance of a CO_(2) air source heat pump water heater

为了定量探究CO_(2)空气源热泵热水器系统性能随风机转速的变化规律,通过试验研究了不同工况下,改变风机转速对排气压力、过热度、CO_(2)质量流量、系统制热量、系统总功耗以及制热性能系数COP的影响;利用响应曲面法对试验进行了优化分析,同时利用试验数据拟合了COP回归模型,并进行可信度分析;通过回归模型预测了系统的最优运行工况并进行试验验证。结果表明:在压缩机频率和电子膨胀阀(EEV)开度一定的情况下,存在着最佳风机转速;在45~85 Hz范围内,随着压缩机频率的提高,COP先增大后减小,增幅最高可达8.97%,各频率下COP最大时对应的最佳风机转速不断减小;随着EEV开度在35%~55%范围内不断增大,COP先增大后减小,增幅可达到6.6%,各EEV开度下COP最大时对应的最佳风机转速不断增大;当压缩机频率为65 Hz、EEV开度为50%时,对应的最佳风机转速为1000 r/min,系统COP达到峰值(4.09)。本文所拟合的COP回归模型最大误差为4.5%;预测系统最优运行工况为:压缩机频率68 Hz、EEV开度52%、风机转速956 r/min,此时系统COP最大,可达到4.29,预测误差为3.7%。本研究可为CO_(2)空气源热泵热水器系统保持高效运行提供理论指导。

In order to quantitatively explore the change law of the CO_(2) air source heat pump water heater system performance with fan speed,the influence of fan speed change on discharge pressure,superheat,CO_(2) mass flow rate,system heating capacity,total power consumption of the system and the coefficient of heating performance COP under different working conditions were studied through experiments.The response surface method was used to optimize the experiment,and the COP regression model was fitted with the experimental data and the reliability analysis was carried out.The optimal operating condition of the system was predicted by the regression model and verified by the experiment.The results show that there is an optimal fan speed existing in CO_(2) air source heat pump water heater when the compressor frequency and opening of the electronic expansion valve(EEV)is constant.In the range of 45~85 Hz,with the increase of compressor frequency,the COP increases first and then decreases with the increase reaching up to 8.97%,and the optimal fan speed corresponding to the maximum COP at each frequency decreases continuously.In the range of 35%~55%,with the increase of EEV opening,the COP increases first and then decreases,with an increase of 6.6%,and the optimal fan speed corresponding to the maximum COP under each EEV opening increases continuously.When the compressor frequency is 65 Hz and the EEV opening is 50%,the corresponding optimal fan speed is 1000 r/min,and the system COP reaches its peak(4.09).The maximum error of COP regression model fitted is 4.5%.The predicted optimal operating conditions of the system are as follows:Compressor frequency is 68 Hz,EEV opening is 52%,and fan speed is 956 r/min.Under this operating condition,the COP of the system reaches the maximum value of 4.29,and the prediction error is 3.7%.This study can provide theoretical guidance for CO_(2) air source heat pump water heater system to maintain efficient operation.