Analysis on Thermal Characteristics of Trapezoidal Wall Based on Phase Change Materials in Solar Greenhouse

doi:10.3969/j.issn.1000-6362.2019.10.002

Abstract

Abstract: In order to explore the effect of phase change materials on the inner temperature of the solar greenhouse, the solid-liquid phase change composite material, in which paraffin wax was a main component, was sprayed onto the inner surface of north trapezoidal wall in the solar greenhouse. Then, the heat flux, temperature near the north trapezoidal wall, and the temperature indoor and outdoor both in the sprayed greenhouse and ordinary greenhouse were measured and analyzed by performing typical weather and monthly changed. The results showed that the heat storage in day-time and heat release in night-time of the north trapezoidal wall in the phase change coated greenhouse was significantly higher than that in the ordinary greenhouse (P<0.05). There was a certain difference in the temperature of the same layer and the same typical time of the phase change coating greenhouse and the ordinary greenhouse, which decreased gradually with the depth increasing of the north wall, and the difference between 0?300mm was the most significant (P<0.05). The daily average value of accumulated heat storage in the phase change coating greenhouse was 8.1% higher than that of the ordinary greenhouse, and the daily average value of accumulated heat release was 14.8% higher than that of the ordinary greenhouse.There was a significant difference between the monthly average temperature at the surface and the various inner layers in the north wall of the phase change coating and the ordinary greenhouse (P<0.05). The monthly average temperature in the phase change coating greenhouse, ordinary greenhouse and outdoor were 9.93℃, 8.63℃ and -8.91℃, respectively. It indicated that the phase change coating north wall effectively increased the heat storage and heat release and enhanced the greenhouse air temperature, especially the night temperature.

Key words: Solar greenhouse, Wall, Heat flux, Temperature, Phase change material

LI Peng, ZHANG Ya-hong, BAI Qing, HU Wei, JIANG Li, ZHAI Xue-ning. Analysis on Thermal Characteristics of Trapezoidal Wall Based on Phase Change Materials in Solar Greenhouse[J]. Chinese Journal of Agrometeorology, 2019, 40(10): 620-629.

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