Shapefactor-equations for radiation heat transfer between plane rectangular surfaces of arbitrary position and size with parallel boundaries

Calculations of radiation heat transfer between arbitrarily positioned surfaces require a knowledge of shapefactors. In this paper the determination of shapefactors between two plane rectangular surfaces of arbitrary position and size with parallel boundaries is described for three different cases: the planes carrying the two surfaces are inclined at an arbitrary angle alpha or are perpendicular or parallel. The evaluation of the derived equations is easily carried out by a computer only requiring an average computing time of about 0.033 sec for one shapefactor.