抄録
The radiation characteristics of the frost layer(reflectance,transmittance and absorptance )were measured using three kinds of the radiative energy source having various wavelength spectra. It was clarified that the monochromatic transmittance of the frost layer in the visible and infrared wavelength ranges was a law constant value. The reflectance and absorptance of the frost layer increased with an increase in the frost height and density,on the other hand,the transmittance of the frost layer decreased with increasing those values. The reflectance,absorptance and transmittance of the frost layer on melting process by radiative energy had the same tendency as on frosting process in both visible and infrared wavelength ranges. Furthermore,the reflectance and transmittance of the frost layer in the infrared wavelength range were lower than those in the length range tended to be while the absorptance in the infrared wavelngth range tended to be higher. It was found that the directional reflectance increased with an increase in the frost density and the frost height. The angular characteristics of reflectance of the frost layer were also affected strongly by the reflectional properties of the cooling surface with a decrease in the frost height, frost density or an increase in the frost melting time.
