太阳能补热热泵供暖实验及地温场热均衡模拟研究

Heating experiments of a solar-assisted heat pump and thermal equilibrium simulations of geothermal fields

为探索多能互补的清洁能源供暖技术,满足北京市村镇分散式建筑清洁供暖需求,在北京农村地区建设太阳能-地源热泵复合式系统,进行太阳能补热热泵供暖实验,并利用COMSOL软件开展地温场热均衡模拟研究。结果表明:相较单一地源热泵系统,太阳能补热热泵供暖方案下,地源侧出水温度提升23%,系统制热能效比(Coefficient of Performance,COP)和机组COP分别提升19%、25%;系统运行10 a,地源热泵系统单季节运行方案下总的取热量要多于间歇期自然恢复量,地温场总均衡为-8.91×10^(9)kJ;单一地源热泵方式运行和太阳能补热方式运行在双季节情况下总的取热量小于总的排热量,地温场总均衡分别为4.220×10^(9)、1.084×10^(10)kJ。因此,双季节运行方案对地温场不会产生负均衡,反而会对地温场有一定的热量补充。地源热泵系统运行中加入太阳能补热,对地温场的影响更小,可显著提升系统和机组效率,该模式适用于北京农村地区特别是供暖需求较大的建筑。

This study aims to explore technologies required for clean energy heating by means of multi-energy comple-mentation,with the purpose of meeting the demand for clean heating in decentralized buildings in Beijing's villages and towns.To this end,this study built a solar-ground source heat pump(SGHP)compound system in a rural area of Beijing.Then,it carried out heating experiments of the solar-assisted heat pump system and thermal equilibrium simulations of geothermal fields using the COMSOL software.The results are as follows:(1)Compared to a single SGHP system,the solar-assisted heat pump scheme increased the outlet water temperature on the ground source side by 23%and increased the coefficients of performance(COP)of the heat pump system and units by 19%and 25%,respectively.(2)After ten years of operation of the system,the scheme of a single season operation using a single SGHP system exhibited a total extracted heat higher than the natural recovery in the intermittent period,with a total balance in the geothermal field of-8.91×10^(9)kJ.(3)The schemes of two-season operation using a single SGHP and a solar-assisted heat pump individu-ally yielded total extracted heat less than that the total discharged heat,with total balances in geothermal fields of 4.220×10^(9)kJ and 1.084×10^(10)kJ,respectively.Therefore,the dual-season schemes will not produce a negative heat bal-ance to the geothermal field but a certain heat supplement instead.Supplementing solar energy to the SGHP system during its operation exerts a smaller impact on the geothermal field and can significantly improve the efficiency of the heat-ing pump system and units.This mode is suitable for rural areas in Beijing,especially for buildings with high heating de-mand.