In a new project, Wageningen UR is working the required measurement protocols for the development of a standardized method to calculate the energy savings of screens. The project focuses on improving the energy saving performance of screens, by influencing some aspects of a screen.
Saving energy with the project ‘Screen Performance’
The project “Screen Performance” will focus on the three main aspects that affect the energy saving of a screen: the thermal radiation losses, for which it is essential to know the emissivity and reflectivity of each screen, in order to estimate how much thermal energy is transmitted; the air permeability of the screen, which will be characterized at a wider range of air velocities to account for the forced convection that the increasingly used internal fans may have; last, a methodology will be developed to estimate the water vapor permeability of each screen, that reproduces as faithfully as possible the temperature, humidity and air velocity conditions normally encountered in commercial greenhouses.
Working together with the industry
The aim of the project “Screen Performance", is that a group of companies of screen producers, textile and building material industry and Wageningen UR Greenhouse Horticulture will work together to develop the required measurement protocols that aim at finally having a standardized methodology to calculate the energy saving parameter of each screen.
Screens in The New Cultivation
One of the main pillars of the New Cultivation (Het Nieuwe Telen) consists on making an intensive use of screens, especially under low light conditions, with the purpose of saving large amounts of fossil energy, but also to limit radiative heat losses from the canopy, thus preventing condensation and causing a more uniform vertical temperature profile on it. When a grower has to choose an energy saving screen, an essential information is obviously, the energy saving parameter (%). So far, each company provides a value which is estimated using different methodologies.