R134a螺旋套管冷凝器换热特性及其对热泵性能的影响研究

摘要

为了研究R134a在螺旋套管冷凝器换热性能及其对热泵运行性能的影响,论文采用实验手段,在以水为冷却介质进行循环加热和直流稳态2种条件下,测试了不同进水流量和入口水温状态时R134a在螺旋套管冷凝器内的换热性能和热泵的运行性能.结果表明:循环加热时,同一进水流量随入口水温的升高,冷凝器总换热量、系统制热量和制热性能系数COP减小,而总换热系数和系统输入功率增大;进水流量从1.19 m3/h增大到2.16 m3/h,入口水温从30℃升高到60o℃时,系统输入功率的增大范围为750 ～900W,制热量的减小范围为600 ～750W,COP的减小范围为2.8 ～3.2,同时流量2.16 m3/h的总换热量的减小量是流量1.19 m3/h的2.5倍,总换热系数的增大量是流量1.19 m3/h的2倍.直流稳态时,进水流量从0.26 m3/h增大到0.71 m3/h,总换热量和总换热系数分别增加了15％和41％;压缩机的排气功力和系统输入功率分别下降了26％和12％,而吸气功力变化较小.%In order to study the influence of R134a on the heat transfer performance of spiral casing condenser and the runnability of heat pump.This paper used water as the medium,and different inflow discharge and inlet water temperature of the condenser in the case of cyclic heating and steady state were tested.The results indicate that in the case of cyclic heating,with the inlet water temperature increase,the total heat transfer rate,the heat output and COP decrease,and the total heat transfer coefficient and the input power increase.When the inlet water temperature increases from 30 ℃ to 60 ℃ and the inflow discharge increases from 1.19 m3/h to 2.16 m3/h,the input power increases from 750W to 900W,the heat output decreases from 600 W to 750 W,COP decreases from 2.8 to 3.2.The decrement of the total heat transfer rate of 2.16 m3/h water inflow is 2.5 times as much as that of 1.19 m3/h water inflow.The increment of the total heat transfer coefficient is 2 times as much as that of 1.19 m3/h water inflow.At the steady state condition,when the inflow discharges increase from 0.26 m3/h to 0.71 m3/h,the total heat transfer rate and the total heat transfer coefficient increase by 15％ and 41％,respectively.The exhaust and the input power decrease by 26％ and 12％,respectively,and the suction pressure change less.