Indoor air temperature and humidity variation of a greenhouse base on field test: A case study in Shandong

Abstract

The indoor thermal and humid environment of the solar greenhouse, especially the air humidity, is studied by the field test and psychrometric chart. First, the air temperature and relative humidity, and solar radiation in the greenhouse were tested by field tests. According to the test results, Solar radiation has a great influence on the air temperature and relative humidity in the greenhouse. The air temperature and relative humidity in a greenhouse vary dramatically in the presence of solar radiation. At night, although the indoor air temperature meets the requirements of crop growth, indoor relative humidity is close to 90%, far higher than the suitable relative humidity area (60-65%). Then, the night air condition was analyzed based on the psychrometric chart. Indoor air does not need to be dehumidified, but could be heated to the greenhouse to reduce the relative humidity. Finally, the variation of indoor air humidity ratio was analyzed. Solar radiation and natural ventilation are important factors affecting the variation of the humidity ratio of indoor air in the solar greenhouse. During the test period, solar radiation increases the humidity ratio of indoor air, and natural ventilation reduces the humidity ratio of indoor air in the solar greenhouse.