Recently, the Team of Plant Environmental Engineering of Protected Agriculture at the Institute of Environment and Sustainable Development in Agriculture, Chinese Academy of Agricultural Sciences, proposed a heating and dehumidification system based on cascade utilization of solar energy for large-span greenhouses during winter nights. The related findings have been published in Renewable Energy.
Fig.1(a) Working principles of the dehumidification and heating system for large-span greenhouses;
(b) Flow chart of daytime and night operations of the system; (c) Variation of the system's air conditions.
Large-span greenhouses are widely used in cold northern China. However, they are often characterized by low temperature, high humidity and limited ventilation during winter nights, increasing the risk of condensation and crop diseases while inhibiting crop transpiration and nutrient absorption. Traditional ventilation, heat pumps or single heat storage methods remain insufficient in terms of energy consumption, susceptibility to external weather conditions, and coordinated temperature and humidity regulation.
The system (AS-HD) is composed of a composite multi-curved trough collector (CMTC), a multi-layer adsorption dehumidification box (MADB) and a U-shaped buried pipe soil heat storage unit. During the daytime, CMTC heats air to drive the desorption and regeneration of desiccants, and stores excess heat in the soil; during the nighttime, MADB is used for adsorption dehumidification and adsorption heat release, after which low-temperature air inside the greenhouse is further heated through heat exchange with the soil via buried pipes before being recirculated back into the greenhouse. This study achieves coordinated greenhouse temperature and humidity regulation through "solar heat collection - day-night dehumidification and regeneration - soil heat storage" coupling. The results show that the system can reduce the relative humidity inside a greenhouse by an average of 7.1%, optimize the range of humidity fluctuations to 70.4%-83.8%, and increase the average temperature by 2.3℃.
This work was supported by the National Key Research and Development Program of China, the Science Innovation Project of the Chinese Academy of Agricultural Science, the Central Guidance for Local Science and Technology Development Fund, etc.
Linkage: https://doi.org/10.1016/j.renene.2025.125087
