Heat Storage Charateristics of a Well Water Spraying Greenhouse with Double Internal Curtains

Abstract

This report investigates the heat storage characteristics of a well water spraying greenhouse with double internal curtains which allows the subsidiary use of hot water heating device.
1) An excllent overall heat transfer coefficient of 0.96Kcal/m²hr°C is obtained with the greenhouse where well water of about 17°C is sprayed over transparent curtain above a reflective curtain maintaining room temperature of 20°C.
2) Compared with a greenhouse with single intenal curtain and well water spraying but without heater, high soil temperature differences more than 10°C and small, upwards soil heat conduction at 6a.m. are new features of the present system.
3) The soil heat conduction of surface layer turns upwards during the night time from downwards during the day time. But this heat conduction is small and has comparatiwely insignificant effects on the heat storage characeristics.
4) The heat released through well water spraying increases with a decrease in ambient temperature. This satisfies an important requisement for the heat storage characteristics of greenhouse.
5) The heat transfer eoeffieient of the well water spraying over curtain alone is calculated after subtracting the effects of the outermost panel and reflective curtain.