寒冷地区空气源热泵的供热特性分析

Analysis of Heating Characteristics on Air Source Heat Pump in Cold Region

针对常规空气源热泵在寒冷地区应用普遍存在的压缩机排气温度高、蒸发器表面结霜和系统性能低等问题,建立了一套低温型空气源热泵供热系统,开展冬季供热实验并实测系统性能,选取典型工况进行瞬时特性分析。结果表明,系统在寒冷地区具有较好的供热性能;单个加热周期分三个基本阶段,逆向循环除霜对水箱温度影响较大;环境温度为-3.73℃时进行地暖供热,将200 L水从38℃加热到45℃耗时23.5 min,平均COPh为2.28;随着环境温度的升高,COPh逐渐增大,环境温度为-9℃,水箱温度为41℃时,系统COPh仍在2.0以上。

The conventional air source heat pump has poor thermal performance in lower environmental temperature in cold region like Lanzhou city,because of the higher exhaust temperature in compressor and easier frosting on the surface of the fins in evaporator.The experimental set-up of the air source heat pump system for space floor heating was established in Lanzhou,transient characteristics of the system in many conditions was obtained.The experimental results show that the system has better thermal performance in Lanzhou city.Three basic periods exist in a single heating cycle called beginning to space heating period,heat pump space heating period and only space heating period.The defrosting process in inverse cycle has a significant effect on the water temperature in the hot water tank.When the ambient temperature is-3.73℃,it takes 23.5 min to heat 200 L water from 38℃to 45℃,and the average COPh is 2.28;The COPh will rise with increaseing of the environmental temperature,which can reach larger than 2.0,when the environmental temperature and hot water temperature are-9℃and 41℃,respectively.