HEAT RADIATION PHENOMENA FROM A GREENHOUSE CROP CANOPY AT NIGHT: 1. THE CURTAIN EFFECT IN A GREENHOUSE COVERED WITH TRANSMITTIVE MATERIAL.

In previous papers the author introduced a curtain factor which enables engineers and growers to make a qualified distinction between materials which may be used for heat saving purposes in greenhouse production (Amsen, 1974).

This curtain effect was based on the assumption that the greenhouse cover (e.g. glass) acted as a black body (e=1) in respect to emitted radiation.

This of course is neither true nor satisfying.
Greenhouses are built not only of glass, but also of materials which have a more pronounced transmissivity to long wave radiation.

In those cases the curtain effect may be extended to comprise the transmissivity of the greenhouse cover (t_h) and the curtain factor (c_s) according to:

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Technical and Physical Aspects of Energy Saving in Greenhouses

M.G. Amsen

https://doi.org/10.17660/ActaHortic.1977.70.2