| In order to study the ability of solar greenhouses to heat storage in winter,four different wall structure solar greenhouses were selected for this experiment,namely No.1traditional active heat storage greenhouse(1#),No.2 phase change solidified soil active heat storage greenhouse(2#),No.3 cast-in-place concrete passive heat storage solar greenhouse(3#),No.4 modular plain soil active heat storage greenhouse(4#)based on the actual situation of solar greenhouse development and the previous research of the research group.Monitor and analyze indoor temperature,humidity,light density and wall heat flow in the test greenhouses in winter,compare the thermal storage performance of the different greenhouse back wall and according to the growth of crops in the greenhouse combined with the construction costetc.,to evaluatetheir application effect in the Yangling area.The main results are as follows:(1)Under typical sunny conditions,the average nighttime air temperature of 1#,2#,3#,4#and outdoor is 15.7,16.4,16.6,17.8,and-3.9°C,respectively,4#is 2.1,1.4,1.2°C higher than 1#,2#,and 3#,respectively;Under typical cloudy conditions,the average nighttime air temperature of 1~4#and outdoor is12.4,13.8,13.1,13.8,-7.3°C respectively,4#is 1.4,0,0.7°C higher than 1#,2#,3#,respectively;Under continuous snow days,the average air temperature of 1~4#and outdoor is 7.9,8.9,8.7,9.5,-2.9°C,4#is 1.6,0.6,0.8°C higher than 1#,2#,3#;The indoor air temperature of 4#is the highest.(2)The average relative humidity of 1~4#and outdoor is 73.6%,78.1%,77.4%,81.1%and 64.7%in typical sunny days,respectively;74.3%,88.4%,89.4%,91.8%and 45.3%in typical cloudy days;93.8%,86.3%,98.8%,99.1%and 90.1%in continuous snow days respectively.The relative humidity of indoor air is high at low temperature.(3)The average soil temperature of 1~4#and outdoor is 16.79,16.04,16.10,14.70,0.56°C respectivelyunder typical sunny conditions,and the difference between the highest temperature and the lowest temperature of soil is 3.95,1.42,2.00,2.54 and 3.65°C respectively.The average soil temperature of 1~4#and outdoor is 13.96,14.25,13.50,12.29,and 0.15°C respectively in typical cloudy conditions,and the soil temperature difference is 2.28,1.67,1.75,1.85,and 0.99°C,respectively.The average soil temperature of 1~4#and outdoor is 12.53,12.79,12.83,11.67 and 0.98°C,and the soil temperature difference is 3.33,2.44,2.39,2.48 and 0.51°C.The soil temperature of 1#fluctuates greatly,and the other 3 are relatively stable.The 4 test greenhouses can guarantee higher soil temperature under low temperature conditions,which is conducive to crop growth.(4)Regardless of typical sunny days,typical cloudy days and continuous snow days,in the depth range of 0-300 mm,the wall thickness of 3#is greatly affected by solar radiation due to the thin wall thickness,and the wall temperature fluctuates greatly.The other three greenhouses are relatively more stable,compared to 2#and 4#,1#is lower in wall temperature.In the depth range of 400-1 000 mm,1#wall temperature is the lowest,and 2#wall temperature is the highest.4#Wall temperature distribution is the most uniform.(5)Look from the heat flow situation,the indoor thermal environment of 4#is best.The effective accumulated temperature of 1~4#during the monitoring period is 168.0?186.5?187.4?195.7°C·d,respectively.The output per unit area of 1~4#was 11.178,12.852,13.176,13.554 kg/m~2 respectively,and the output per unit area of 2#,3#,4#was increased by 14.98%,17.87%,21.26%respectively,the difference was significant(P<0.05).(6)The construction costs of 1~4#are 461.1,389.9,470.4,and 299.0 yuan/m~2,respectively,and 4#is 162.1,90.9,and 171.4 yuan/m~2 lower than 1#,2#,and 3#,respectively.Through the monitoring and analysis of the four greenhouse environments in this study,it is considered that the modular plain soil active heat storage greenhouse(4#)'s indoor thermal environment is good,the indoor plant yield is high,the construction is convenient,and the unit cost is low,which can be promoted within a certain range. |
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