NEW DEVELOPMENTS OF ENERGY-SAVING GREENHOUSES WITH A HIGH LIGHT TRANSMITTANCE

The scope of this investigation is the development of a new energy-saving greenhouse with a high light transmittance. With GE-Plastics a new Zigzag double-web structure is developed which combines energy saving and a high light transmission. The following factors were taken into account: light transmittance, insulation value, material consumed and material strength. The insulation value of the sheet was calculated according a European Standard method with a computational fluid dynamics (CFD) program. An extra advantage of these zigzag-sheets is that they can be built in without glazing bars. These double structures of ARM-glass or the Zigzag Lexan can just compensate the light losses caused by an extra layer. Therefore this material combines high light transmittance with good thermal insulation. With the simulation program “Kaspro” we can predict the year round energy consumption of greenhouses with hourly climate data. Different greenhouse constructors have build Venlo type greenhouses and also a wide span greenhouse.