光伏直驱的太阳能跨季节储热系统试验研究

Experimental study on the solar seasonal storage system direct-driven by photovoltaic

针对太阳能跨季节储热系统中存在控制复杂、电耗较高等问题,文章设计一种光伏直驱的太阳能跨季节储热系统,并搭建试验平台,探究不同工况下系统电、热性能。结果表明,光伏直驱的太阳能跨季节储热系统运行无需控制系统及市电消耗,光伏电池通过影响水泵输入功率来控制系统流量,系统在2.45 m^(2)光伏电池驱动下,于辐照度420 W/m^(2)时启动。辐照度小于750 W/m^(2)时,流量变化趋势与辐照度变化趋势相同;大于750 W/m^(2)时,流量趋近稳定。该系统晴天与多云天太阳能储热率分别为35.68%和29.12%,较温差控制式系统分别高6.56%和7.29%,光伏利用效率分别为78.60%和86.01%。集热/储热流量比的变化对系统性能影响较小,应关注水泵启停辐照度的合理优化设计及蓄电池等储能装置的加入。

Aiming at the problems of complex control and high electrical consumption in solar seasonal storage system,solar seasonal storage system direct-driven by photovoltaic is proposed,and a test platform is built to investigate the electrical and thermal performance of the system under different working conditions.The test results show that the solar seasonal storage system direct-driven by photovoltaic does not require complex control system access and municipal power consumption,and the photovoltaic cell affects the system flow by affecting the input power of the water pump.The system is driven by 2.45 m^(2) solar cell and activated at a solar irradiance of 420 W/m^(2).When the solar irradiance is less than 750 W/m^(2),the flow rate changes have a same trend with the solar irradiance;when it is greater than 750 W/m^(2),the flow rate tends to be stable.The system has better thermal performance than the traditional temperature difference control system.The solar heat storage rates of the system in sunny and cloudy days are 35.68%and 29.12%respectively,which are 6.56%and 7.29%higher than the traditional temperature difference control system,and the average photovoltaic efficiency is 78.60%and 86.01%respectively.The change of heat collection/storage flow ratio has little impact on the system performance,attention should be paid to the reasonable and optimal design of pump start-stop irradiance and the inclusion of energy storage devices such as batteries.