光伏/光热-地源热泵联合供热系统运行性能研究

为解决太阳电池的发电效率随温度升高而下降以及地源热泵系统供热引起的土壤热失衡问题,以典型居住建筑的光伏/光热-地源热泵（PV/T-GSHP）联合供热系统为研究对象,基于TRNSYS软件,采用土壤温度、地源热泵机组季节能效比、光伏发电效率和太阳能保证率为评价指标,对该联合供热系统进行运行性能分析。研究结果表明：夏热冬冷地区（以长沙为例）太阳能保证率相对较高,PV/T组件面积为满屋顶最大化安装（900 m²）时,第20年末土壤温度相比初始地温仅升高0.8 ℃,热泵机组季节能效比约为5.1,太阳能保证率为97.0%~98.7%;不同气候地区的太阳能保证率与PV/T组件面积和建筑全年累计供热量有关,通过定义单位建筑全年累计供热量PV/T组件面积指标,得到中国不同气候地区的太阳能保证率与该指标的耦合关系,回归方程的决定系数R²为0.983,得出在已知建筑全年累计供热量和太阳保证率设计目标值的条件下所需PV/T组件面积的计算方法。PV/T-GSHP联合供热系统的全年运行能耗显著小于平板太阳能集热器-地源热泵联合系统（最小降幅为沈阳,49.7%）,远小于空气源热泵（最小降幅为石家庄,79.8%）和燃气壁挂炉（最小降幅为沈阳,65.1%）。

PERFORMANCE ANALYSIS FOR SOLAR PHOTOVOLTAIC/THERMAL-GROUND SOURCE HEAT PUMP HYBRID HEATING SYSTEM

In order to solve the problem that the electrical efficiency of photovoltaic cells decreases with the increase of temperature, and the soil heat imbalance caused by ground source heat pump system heating, the operation performance of the solar photovoltaic/thermal-ground source heat pump （PV/T-GSHP） hybrid heating system is investigated using TRNSYS software. A typical residential building model is used, and the soil temperature, seasonal coefficient of performance for heat pump units （SCOP_HP）, photovoltaic electrical efficiency and solar fraction are taken as the evaluation indexes. It is found that： the solar fraction is relatively high in hot summer and cold winter region（take Changsha as a case）, the soil temperature at the end of 20^th years is only 0.8 ℃ higher than the initial ground temperature, the SCOP_HP is about 5.1 and the solar fraction is 97.0%-98.7%, when the PV/T modules are installed on full of the roof （900 m²）; The solar fraction in different climate regions is related to the area of PV/T modules and the cumulative heat load of building. By defining the index, PV/T module area per accumulated heat load of building, the coupling relationship between the solar fraction and the defined index in different climate regions of China is obtained. In the regression equation, the coefficient of determination, R², is 0.983. The area of PV/T modules required can be calculated from the regression equation when the building cumulative heat load and solar fraction are known. The annual primary energy consumption of PV/T-GSHP hybrid heating system is significantly less than that of flat panel solar collector and ground source heat pump hybrid heating system （the minimum decrease is in Shenyang, 49.7%）, much less than that of air source heat pump system （the minimum decrease is in Shijiazhuang, 79.8%） and gas wall mounted furnace system （the minimum decrease is in Shenyang, 65.1%）, respectively.