Articles
GREENHOUSE COOLING BY NIR-REFLECTION
Article number
719_8
Pages
97 – 106
Language
English
Abstract
Wageningen UR investigated the potential of several NIR-filtering methods to be applied in horticulture.
In this paper the analysis of the optical properties of available NIR-filtering materials is given including a calculation method to quantify the energy reduction under these materials and to estimate the contribution for greenhouse cooling.
It can be concluded that the optimum NIR-filtering material is still not found but there is good potential for further developments.
NIR-filtering multilayer coatings applied to plastic film or glass filter out NIR most effectively.
NIR-filtering is not desirable during winter-time in most climatic regions.
Therefore, NIR-filtering coverings should not be used in unheated greenhouses since they cause an undesirable temperature drop.
NIR-filtering white washes still reduce PAR too much.
NIR-filtering (moveable) screens could be an alternative in the future.
Future studies should also investigate whether it is possible to use the reflected NIR energy for other processes or cost-effectively storage.
In this paper the analysis of the optical properties of available NIR-filtering materials is given including a calculation method to quantify the energy reduction under these materials and to estimate the contribution for greenhouse cooling.
It can be concluded that the optimum NIR-filtering material is still not found but there is good potential for further developments.
NIR-filtering multilayer coatings applied to plastic film or glass filter out NIR most effectively.
NIR-filtering is not desirable during winter-time in most climatic regions.
Therefore, NIR-filtering coverings should not be used in unheated greenhouses since they cause an undesirable temperature drop.
NIR-filtering white washes still reduce PAR too much.
NIR-filtering (moveable) screens could be an alternative in the future.
Future studies should also investigate whether it is possible to use the reflected NIR energy for other processes or cost-effectively storage.
Publication
Authors
S. Hemming, F. Kempkes, N. van der Braak, T. Dueck, N. Marissen
Keywords
near infrared radiation, spectral filter, greenhouse covering, plastic films, coatings, greenhouse climate, climate model
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