ENERGY SAVING GREENHOUSE WITH WATER CURTAIN DEVICE

Since 1979, the author has measured and clarified the insulation characteristics of various multi-span greenhouses with single, double and triple movable curtains with the water curtain device; that is an inner equipment composed of a slope roof shaped movable curtain on which wellwater was sprayed, a spray pipe and two drain troughs.

When we compared these greenhouses in regard to the structures, the room air temperatures, the overall heat transmission coefficient, the spray water flow and spray water heat release, the water curtain showed higher resisting characteristics to night time cooling.

In 1987, we investigated similarly the insulation characteristics of a newly developed so called curved roof greenhouse with the water curtain.
At this curved strawberry house, a room thermostat was introduced to on-off control the water spray.
We compared the insulation effect of the curved water curtain of the test house with that of the control house which has the double film tunnel.

A simple thermostat worked effectively to control intermittently the spray water flow with some surplus capacity of pumping.

The curved water curtain is cheap and recommendable to practical use as it holds certainly the room air temperature at 8 °C and soil temperature at 10 °C during winter nights.

Symposium on High Technology in Protected Cultivation

Y. Ogura

https://doi.org/10.17660/ActaHortic.1988.230.72