Effects of a solar heating system on the microclimate of an agricultural greenhouse. Application on zucchini (Cucurbita pepo)

•Impact of the solar heating system installed in double glazing at the roof level, and the storage system on the microclimate of the study greenhouse.•Estimation of the energy conveyed by the coil during the day, and of the restituted energy through the storage tanks during the night.•The performance of the active solar system compared with the passive solar system.•Effect of the solar system on the development of zucchini plant. Agricultural production has made records thanks to new heating systems that are more economical and less costly, able to cope with the temperature drops of the microclimate of agricultural greenhouses while promoting the profitability of products in terms of quality, quantity and duration of growth. This work focuses on studying experimentally the effect of a solar heating system (SHS) on the microclimate of an agricultural greenhouse. This heating system is a combination of a copper tube placed between the double roof glazing and a sensible heat storage system. This installation is based on the daily thermal conversion of solar energy and its storage for night restitution. This experimentation also includes a second control greenhouse (GC) without any heating system that allows comparison at different stages of crops growth under the agricultural greenhouses. The results of this experiment during the cold season are reflected in a temperature gain on the experimental greenhouse (GE) by 4 °C compared to the GC and 6 °C compared to external ambient air. In addition, the relative humidity recorded for the GE was in the range [70%; 74%] against [78%; 96%] in the GC. However, the relative humidity of ambient air was between [90%; 99.9%]. For the efficiency of the SHS reached out 73%. As for the cultivation under the GE equipped with a SHS, the zucchini plants developed the fruit 16 days earlier than the zucchini plants grown under the GC.