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Cover materials excluding Near Infrared radiation: what is the best strategy in mild climates?
- Source :
- Acta Horticulturae 807 (2009), Acta Horticulturae, 807, 67-72
- Publication Year :
- 2009
-
Abstract
- Only about half of the energy that enters a greenhouse as sun radiation is in the wavelength range that is useful for photosynthesis (PAR, Photosynthetically Active Radiation). Nearly all the remaining energy fraction is in the Near InfraRed range (NIR) and only warms the greenhouse and crop and does contribute to transpiration, none of which is necessarily always desirable. Materials or additives for greenhouse covers that reflect a fraction of the NIR radiation have recently become commercially available. Besides lowering greenhouse temperature, a NIR-excluding cover has quite a few side-effects that may become quite relevant in the passive or semi-passive greenhouses typical of mild climates. For instance, the ratio of assimilation to transpiration (the water use efficiency) should increase. On the other hand, by lowering the ventilation requirement, such a cover may hinder in-flow of carbon dioxide, thereby limiting the photosynthesis rate. In addition, there are obviously conditions where the warming up caused by NIR may be desirable rather than a nuisance. NIR-reflecting materials are becoming available in forms that are suitable for various types of applications, such as permanent, seasonal or mobile. By means of a simulation study, we discuss in this paper the best form of application in relation to the external climate and climate management options available
- Subjects :
- 0106 biological sciences
Infrared
020209 energy
Greenhouse
02 engineering and technology
Horticulture
Atmospheric sciences
Photosynthesis
Wageningen UR Glastuinbouw
7. Clean energy
01 natural sciences
chemistry.chemical_compound
0202 electrical engineering, electronic engineering, information engineering
Water-use efficiency
Transpiration
Sunlight
Hydrology
Shadow screen
Wageningen UR Greenhouse Horticulture
Whitewash
NIR
Greenhouse temperature
chemistry
13. Climate action
Photosynthetically active radiation
Carbon dioxide
Assimilation
Environmental science
010606 plant biology & botany
Subjects
Details
- Language :
- English
- ISSN :
- 05677572
- Volume :
- 807
- Database :
- OpenAIRE
- Journal :
- Acta Horticulturae
- Accession number :
- edsair.doi.dedup.....548d3eff4df7b9359d04c36553f7194b