ISHS Acta Horticulturae 170: Greenhouse Construction and Covering Materials
INFLATED POLYETHYLENE TUBE ENERGY SCREENS FOR GREENHOUSES |
| Authors: | T.H. Short, J. Huizing, J.J. Breuer |
| Abstract:
An inflated plastic tube energy screen for greenhouses with a possible 50 percent nighttime energy saving was developed through a 6-month cooperative program between the Ohio Agricultural Research and Development Center (OARDC) and the National Agricultural Engineering Institute of The Netherlands (IMAG). Suspended tubes from the USA were combined with a moving screen cable drive system from The Netherlands. This IMAG-OARDC model (6.4 m x 6 m) was demonstrated for both inflated closing and deflated openings with day-time storage directly under the gutter. A larger 19.2 m x 30 m screen was designed and built at IMAG in 1983 to test the energy savings at night in glasshouses. The tubes were mechanically deflated and stored during the day. Three comparative 24-hour tests of energy savings ranged from 21.1 percent to 58.9 percent with an average of 35.0 percent. Heat loss by convection was a problem around the unsealed perimeters of the screen mechanism. Another tube screen design was developed and tested in 1984 in Ohio where 37 tubes of 15 cm diameter were simultaneously rolled up at one end of a 30 m long greenhouse. All 37 tubes were fastened to a common header that was 5.5 m long. The header was pulled by cables from the storage roll to the opposite end of the greenhouse. The tubes were inflated after being pulled to form the night screen. The tubes were simultaneously rolled up in the morning for normal greenhouse operation. | |
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