地源热泵系统运行参数及土壤温度变化特性分析

Analysis on operation parameters and soil temperature variation characteristics of ground-source heat pump system

以天津某办公楼地源热泵系统为研究对象,通过采集土壤温度、地源侧取热量、负荷侧供热量、机组耗电量、水泵耗电量等实测的数据,初步分析了热泵设定温度(ST),水泵频率(PF)等因素对于土壤温度、机组性能系数(COP)及系统性能系数的影响.结果表明,在满足室内热负荷的前提下,当热泵设定温度从42℃降低至40℃范围内,每降低1℃,可以减小地下取热量7.80%,系统性能系数提升3.66%;当水泵频率从40 Hz降低至30 Hz范围内,每降低5 Hz,可以减小地下取热量7.72%,系统性能系数提升2.64%.对于热负荷占优的公共建筑,可以通过调节地源热泵机组的设定温度或循环水泵频率,来促使土壤温度向着有利于机组高效运行的方向改变,并保证系统的长期可靠运行.

This paper analyzes the measured data such as soil temperature, heat extraction of ground source side, heat supply of load side, power consumption of heat pump unit and power consumption of pumps of a ground-source heat pump system （GSHPS） for a business building in Tianjin. The influence of setting temperature （ST） and pump frequency （PF） on the soil temperature and coefficient of performance （COP） of heat pump unit or system are studied. The results show that the heat extraction of ground source side reduces 7.80% with 1 ℃ reduction of ST in the case of meeting the indoor heat load as ST changes from 42 ℃ to 40℃, and the COP of system increases 3.66% at the same time. Similarly, the heat extraction of ground source side reduces 7.72% with 5 Hz of PF, as PF changes from 40 Hz to 30 Hz; and the COP of GSHPS increases 2.64% simultaneously. For the heating-dominated building, a suitable operation strategy to adjust ST of the ground source heat pump unit and PF of the circulating pump can make the soil temperature vary in the direction of high efficiency and ensure long-term reliable operation of the system.