INTRODUCTION TO A DISCUSSION

The most important energy saving possibilities are double glazing with glass or plastic, and thermal screens. This could lead to 25–40% and more energy saving.

This % should be precised in different countries with different climats.

However, these methods lead to different "inconveniences" for the grower. Firstly, there is the fact of light reduction in the greenhouse and secondly the price of these materials has to be taken into consideration. The big question the grower has to ask himself is:

• are the nuisances more important than the advantages, or
• are the losses more important than the profits?

In other words: what is the most important aspect, the energysaving or the reduction of the yields?

According to Van de Vooren, calculation and measurement of light reduction is possible and also the calculation of energy saving is a possibility. The problem which remains is the relation between this light reduction and crop yield on short and on long term.

To this I may add: to be considered from a practical point of view, in the work conditions and in less or more income for the grower.

The theoretical aspect of the light reduction is given in Session 2.

Download Adobe Acrobat Reader (free software to read PDF files)