DEVELOPMENT OF AN INTEGRATED LOW ENERGY SYSTEM FOR HEATING PLASTIC GREENHOUSES BY COMBINATION OF RADIANT MULCH FILM TUBES AND THERMAL SCREENS

Advantages and difficulties with the classic radiant mulch film tube system have been discussed and different utilisations of this system have been projected (solar heating as distributor and captor-distributor, geothermy, heat pump, waste heat, etc…).

A new system of radiant mulch film tubes have been proposed and was composed of 50 μm linear black PE or 100 μm normal black PE, with separated canals, obtained by contineous sealing and suitable for only 1 season utilisation. Cost-price of this system is estimated to be 5 times lower than the classic system.

A double layer thermal screen composed of an ordinary PE film of 100 μm and an aluminized PE film has been developed. This screen is movable on a fiberglass arch by means of polyurethane jacks, in which low pressions or depressions are realized by means of an air exhauster.

Results with both systems have been presented an discussed when used individually. Better results are nevertheless obtained by combination of both systems, resulting in an elevation of the minimum temperatures with 4–8°C, which permits increased earliness and quality of the yield with several crops in different experiments.

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