The high summer indoor temperature in agricultural greenhouse is not conducive to crop growth,so it is necessary to cool the greenhouse. In this study,taking the agricultural multi-span greenhouse with strong temperat...The high summer indoor temperature in agricultural greenhouse is not conducive to crop growth,so it is necessary to cool the greenhouse. In this study,taking the agricultural multi-span greenhouse with strong temperature adjustment ability for example,we make an experimental analysis on the temperature changes inside and outside the greenhouse under nine different equipment combinations( fan,skylight,sunshade,sunshade + fan,cooling pad + fan,skylight + fan,sunshade + skylight,sunshade + fan + cooling pad,sunshade + skylight + fan),respectively,and conduct the overall assessment on the measures to cool the summer agricultural greenhouse,in order to provide a reference for selecting a cost-effective cooling method for greenhouse. Tests show that the three treatment modes of fan,sunshade and sunshade + fan almost have no cooling capacity; skylight,sunshade + skylight have cooling capacity,but the effect is slow; cooling pad + fan,sunshade + skylight +fan can reduce the indoor temperature,but the effect is not very good; skylight and fan have good cooling effect; sunshade + fan + cooling pad has obvious cooling effect,which can well meet the cooling needs in the summer greenhouse.展开更多
In order to further understand the changing laws of environmental factors in large multi-span greenhouses under natural ventilation conditions and the internal relations between various environmental factors,and ultim...In order to further understand the changing laws of environmental factors in large multi-span greenhouses under natural ventilation conditions and the internal relations between various environmental factors,and ultimately improve the precision of microclimate regulation of large multi-span greenhouses.Taking the multi-span greenhouse with a small spire structure in the Demonstration Base of Guangdong Agricultural Technology Extension Station as the research object,under the condition of natural ventilation with butterfly-shaped windows,the changes in temperature,humidity,wind speed and solar light intensity of different monitoring planes in the greenhouse were monitored.After analyzing the monitoring data,it was found that:1)The temperature gradient in the vertical direction in the large multi-span greenhouse is more obvious than that in the small greenhouse,and the highest average temperature difference monitored can reach 7.9℃.The velocity field in the multispan greenhouse is always maintained within the range of 0.3-0.4 m/s,and the ambient wind speed has no effect on the airflow speed in the greenhouse.The humidity and speed in the multi-span greenhouse show good uniformity.2)In a large multi-span greenhouse,the secondary radiation generated by the internal shading has less impact on the area near the ground,which can effectively reduce the ground temperature.3)Under the conditions studied in this research,the temperature and humidity in the greenhouse follow the external environment as well,showing that the greenhouse design is reasonable,and the air renewal and heat exchange inside and outside the greenhouse are good during natural ventilation.展开更多
基金Supported by Scientific and Technological Achievement Extension Project of Experimental Demonstration Station(Base)in Northwest A&F University(TGZX2016-31)Xi'an Science and Technology Project(NC1504 3)
文摘The high summer indoor temperature in agricultural greenhouse is not conducive to crop growth,so it is necessary to cool the greenhouse. In this study,taking the agricultural multi-span greenhouse with strong temperature adjustment ability for example,we make an experimental analysis on the temperature changes inside and outside the greenhouse under nine different equipment combinations( fan,skylight,sunshade,sunshade + fan,cooling pad + fan,skylight + fan,sunshade + skylight,sunshade + fan + cooling pad,sunshade + skylight + fan),respectively,and conduct the overall assessment on the measures to cool the summer agricultural greenhouse,in order to provide a reference for selecting a cost-effective cooling method for greenhouse. Tests show that the three treatment modes of fan,sunshade and sunshade + fan almost have no cooling capacity; skylight,sunshade + skylight have cooling capacity,but the effect is slow; cooling pad + fan,sunshade + skylight +fan can reduce the indoor temperature,but the effect is not very good; skylight and fan have good cooling effect; sunshade + fan + cooling pad has obvious cooling effect,which can well meet the cooling needs in the summer greenhouse.
基金financially supported by the National Key Research and Development Program of China(No.2017YFD0701500)the Open Project of the Key Laboratory of Agricultural Facilities Structural Engineering of the Ministry of Agriculture and Rural Affairs(No.202003).
文摘In order to further understand the changing laws of environmental factors in large multi-span greenhouses under natural ventilation conditions and the internal relations between various environmental factors,and ultimately improve the precision of microclimate regulation of large multi-span greenhouses.Taking the multi-span greenhouse with a small spire structure in the Demonstration Base of Guangdong Agricultural Technology Extension Station as the research object,under the condition of natural ventilation with butterfly-shaped windows,the changes in temperature,humidity,wind speed and solar light intensity of different monitoring planes in the greenhouse were monitored.After analyzing the monitoring data,it was found that:1)The temperature gradient in the vertical direction in the large multi-span greenhouse is more obvious than that in the small greenhouse,and the highest average temperature difference monitored can reach 7.9℃.The velocity field in the multispan greenhouse is always maintained within the range of 0.3-0.4 m/s,and the ambient wind speed has no effect on the airflow speed in the greenhouse.The humidity and speed in the multi-span greenhouse show good uniformity.2)In a large multi-span greenhouse,the secondary radiation generated by the internal shading has less impact on the area near the ground,which can effectively reduce the ground temperature.3)Under the conditions studied in this research,the temperature and humidity in the greenhouse follow the external environment as well,showing that the greenhouse design is reasonable,and the air renewal and heat exchange inside and outside the greenhouse are good during natural ventilation.
