磷酸氢二钠相变墙板在温室中的应用效果

为改善日光温室热环境,以十二水磷酸氢二钠为相变材料,依据普通温室墙体夜间累计放热量计算出相变材料的用量为16.7kg/m2,在此基础上制备了十二水磷酸氢二钠相变蓄热墙板。建造后墙结构为"80mm相变蓄热板+40mm×60mm×2.5mm方钢+80mm菱镁聚苯保温板"日光温室,与"240mm红砖+100mm聚苯板+240mm红砖"后墙温室比较。结果表明:典型晴天时,相变蓄热板温室的气温波动幅度比对照小4.2℃,最低气温高1.5℃,最高气温低2.7℃,平均气温高1.2℃,相对湿度增加3%,墙体夜间累计放热量略大于对照;典型阴天时,相变蓄热板温室的平均气温比对照高1.6℃,相对湿度提高2.6%,墙体夜间累计放热量增加0.16MJ/m2。与此同时相变蓄热板墙体造价比对照低22元/m2,土地利用率提高4.2%~12.2%。综合保温蓄热性能和建造成本,相变蓄热墙板是一种有推广价值的温室墙体类型。

Performance of Phase Change Thermal Storage Wallboard of Disodium Hydrogen Phosphate Dodecahydrate in Solar Greenhouses

In order to improve the thermal environment of solar greenhouse,a kind of phase change thermal storage wallboard（PCTSW）was built by using Na2 HPO4·12H20 as phase change materials （PCM）and with 16.7 kg/m2 PCM counted on the basis of heat discharged of north wall in a normal greenhouse at night. A solar greenhouse with PCTSW as north wall materials was built and compared with a normal greenhouse. The results showed that, on typical sunny days, compared with normal greenhouse, the temperature fluctuation in the PCTSW greenhouse was lower by 4. 2 ℃, the minimum temperature was higher by 1.5 ℃, and the maximum temperature was lower by 2. 7 ℃, the average temperature and relative humidity increased by 1. 2 ℃ and 3% respectively, and heat discharged of wall was slightly more. On typical cloudy days, the average temperature of PCTSW greenhouse was 1.6 ℃ higher than the control,relative humidity promoted by 2. 6%, heat discharged of wall increased by 0. 16 MJ/m2. The cost of PCTSW was 22 Yuan/m2 lower than the normal wall, land utilization rate increased from 4. 2% to 12.2% at the same time. Based on the performance of heat preservation and construction cost, it can be concluded that the PCTSW is a valuable greenhouse wall.