Abstract
This research was undertaken to investigate how some improvement of internal side curtain films and the well-water spraying system in a twin-span greenhouse affects the thermal insulation characteristics during the coldest season.
The twin-span greenhouse was covered with PVC, and had an internal movable roof curtain with the well-water spraying system of 4m-interval nozzles, two movable curtains, and a single fixed side curtain. The overall heat transfer coefficient of this greenhouse was calculated at 1.81W·m-2·°C-1.
In the above-mentioned greenhouse, the overall heat transfer coefficient changed into 1.36W·m-2·°C-1, when the internal side curtain with a single-layered film was replaced with the one with double-layered film.
When the well-water spraying system was changed by replacing the hard plastic pipe with 4m-interval nozzles with the plastic film tube with 3cm-interval pores, and was applied to the first greenhouse, the overall heat transfer coefficient became 1.77W·m-2·°C-1.
When this system was applied to the side curtain as well as to the internal movable curtain, the overall heat transfer coefficient was calculated at 1.25W·m-2·°C-1.
