Radiative heat loss inside a greenhouse

Abstract

In this paper the exact solution of a realistic physical model of the thermal radiation exchange inside a single span greenhouse is offered which yields the net radiation flux density at ground level. A similar but approximate model is also offered for a multispan grenhouse. The rate of radiative heat loss was computed for the particular situation when the inside ground, the cladding material and the outside air and ground are all at freezing temperature, and the sky is clear. It turns out that the radiative heat loss rate is nearly the same for the single and for the multispan greenhouse, and is mainly determined by the transmittance of the cladding material, being little dependent on the relative magnitudes of its emittance and reflectance. Finally, the coefficient of radiative heat transfer for the inside ground surface was obtained as well.