ISHS Acta Horticulturae 399: Greenhouse Environment Control and Automation
OPTIMUM SYSTEM OF ZONE COOLING IN GREENHOUSE |
| Authors: | H. Nishina, M. Tanaka, Y. Hashimoto |
| Keywords: | zone cooling, greenhouse, cooling, environment control, simulation |
| Abstract:
For production of high quality plants in greenhouse, cooling in the daytime in summer is necessary in Japan. While cooling of the whole greenhouse is impossible from the viewpoint of energy and cost, cooling of only zone around the plants is considered to be efficient cooling system. Two types of zone cooling systems were constructed in a greenhouse in Ehime University. One was open type and the other was closed type. In the open type, air inside the greenhouse was cooled by an air-to-water heat exchanger, flowed around the plants and returned into the greenhouse. In the closed type, zone around the plants was surrounded by transparent film and air inside the film was cooled by an air-to-water heat exchanger. Cooling experiments were carried out in summer of 1991 and 1992 and performance and efficiency of cooling was investigated. Both the open type and the closed type showed enough cooling performance. However, cooling load in the closed type was about 20% of that in the open type, indicating that the closed type is recommended from the viewpoint of cooling efficiency. Furthermore, modeling and simulation of the closed type zone cooling system was performed. The results indicate that to make the zone cooling system tight as possible is recommended from the viewpoint of cooling efficiency. | |
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