基于热泵的日光温室浅层土壤水媒蓄放热装置试验

    Experimental study on shallow soil assisted heat release-storage system with water-water heat pump in solar greenhouse

    • 摘要: 由于日光温室的蓄热能力有限,后半夜温度往往比较低,难以满足作物生长需求。针对这一问题,该文提出了基于热泵的日光温室浅层土壤水媒蓄放热方法,其原理是白天开启循环水泵,将后墙获得的太阳辐射储存到温室浅层土壤中;前半夜通过浅层土壤热量的自然释放加热温室;当温室温度较低时,启动热泵系统将浅层土壤中的热量提升后加热温室。试验结果表明,在阴天系统系数(coefficient of performance,COP)能达到3以上,与燃煤热水锅炉相比节能33%;与对照温室相比,盖上保温被后,由于试验温室蓄热量大于对照温室,试验温室空气温度和土壤温度分别比对照温室平均高3.2和3.3℃;开启热泵机组后,试验温室空气温度和土壤温度分别比对照温室平均高5.7和2.9℃。

       

      Abstract: During cold winter night, the air temperatures inside solar greenhouses are low for crop growth, especially during the latter half of the night, due to the limited heat storage capacity of the greenhouses. Thus, in the present experiment, a solar and shallow soil assisted heat release-storage system with water-water heat pump was designed. During the daytime, the solar energy obtained from the greenhouse back wall was absorbed and released to the shallow soil using circulated water with a water pump. Before midnight, the heat energy stored in the soil automatically was released to the air inside the greenhouse duo to the temperature differences between the soil and air. When air temperature inside the greenhouse was lower than its set-point, the heat pump was used to exact the heat energy from the soil for heating the greenhouse air. The results showed that the coefficient of performance of the system was more than 3 even on a cloudy day and about 42% energy had been saved compared with conventional coal-fired hot water heating system. After covering the insulation layer, the average air and soil temperature was 3.2 and 3.3℃ higher inside the experimental greenhouse than that in the control greenhouse respectively due to the higher heat storage. After turning on the heat pump, the average air and soil temperature inside the experimental greenhouse was 5.7 and 2.9℃ higher than that in the control greenhouse, respectively.

       

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