文献类型： 外文期刊

第一作者： Tong, Y.

作者： Tong, Y.;Tong, Y.;Kozai, T.;Ohyama, K.;Ohyama, K.

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关键词： Air temperature;CO_2 concentration;Vapor pressure deficit;Sensible heat factor

期刊名称：APPLIED ENGINEERING IN AGRICULTURE （ 影响因子：0.985； 五年影响因子：1.02 ）

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收录情况： SCI

摘要： To produce high-quality greenhouse crops year round, a cooling method to decrease the air temperature is required in summer. In the present experiment, multiple small-capacity (2.8 kW) household heat pumps were used for cooling a greenhouse in Chiba,Japan, during summer nights. The environmental conditions inside the greenhouse, average coefficient of performance (COP) of eight heat pumps, and amount of water drained from the heat pumps were investigated. The results showed that when the heat pumpswere used in the greenhouse, the air temperature, C0_2 concentration, and water vapor pressure deficit were more suitable for crop growth than when the heat pumps were not used. Average COP for cooling ranged from 5.8 to 10.7, which was 1.3 to 2.4 timesgreater than the value obtained under Japanese Industrial Standard conditions, due to the smaller difference in air temperature between inside and outside the greenhouse during the nighttime(20:00-05:00) from20June 20 July 2010. The amount of water drained from the heat pumps accounted for 15% to 25% of the amount of irrigated water. These results indicate that the environmental conditions inside a greenhouse can be improved by using heat pumps during summer nights achieving high COP and low net water consumption.

分类号： S2