苏南地区夏季浅层地热交换对大棚降温效果初探

Preliminary study on the cooling effect of geothermal exchange at the superficial layer on greenhouse in South Jiangsu in summer

为研究苏南地区浅层地热交换系统的降温效果,2016年5月至7月在江苏省张家港市某塑料大棚内进行试验,分别测定棚内60、40、15 cm土层深处地温、换热管道进地处和出地处的温度和湿度,计算并分析焓差、蓄热量、平均热流量、平均热流密度、能效功耗情况。结果表明:在该地区5—7月,试验大棚晴天平均降温为3.4℃,多云天为1.5℃,阴雨天为0.8℃。湿度变化与对照相比差异不显著,晴天在40%~90%之间,多云天在60%~100%之间,阴雨天在80%~100%之间。3个连续晴天中,对照大棚在60 cm土层深处地温基本处于21.3℃的恒温状态,处理大棚在21.8℃±0.4℃平稳波动;对照大棚在40 cm土层处日平均地温为22.7℃,平均以0.1℃/d上升,处理大棚为23.9℃,平均以0.4℃/d上升;对照大棚在15 cm土层处日平均地温为24.8℃,处理大棚为25.7℃,以0.5℃/d波浪式上升。在热交换方面,试验大棚焓差0.166~9.560 kJ/kg,蓄热量3.94×10~5kJ,日耗电能0.8×10~5kJ,能效比4.21。初步证明浅层地热交换系统在苏南地区具有实用可行性。

The area of facility agriculture in China ranks forefront in the world.In recent years,as an emerging technology of environmental management inside the greenhouse,ground source heat pump(GSHP)is sufficiently emphasized by many scholars.While most of them only focus on heating effect of greenhouse rather than its cooling effect,due to some severe crop problems induced by relatively high temperature in South Jiangsu during summer.In this study,some related indexes were analyzed from the perspective of cooling effect,and the effectiveness and practicability of the cooling system were evaluated in the experimental greenhouse.