Energy saving screen materials : measurement method of radiation exchange, air permeability and humidity transport and a calculation method for energy saving

The objectives of the project were the quantifi cation of the greenhouse screen properties (emissivity and transmissivity for thermal infrared radiation, air permeability and humidity transport) and the determination of the total energy saving under defi ned conditions in order to be able to compare the performance of different screens (and suppliers) with each other. This helps growers to understand more about screen properties and allows them to make an informed choice of investment. The results show that impermeable screens and screens with low emissivity and low transmissivity for thermal infrared radiation give highest energy saving. Permeable screens give highest transport for humidity and lowest air humidity during screen usage without the need for additional mechanical dehumidifi cation.