ing the heating and cooling rate of the receiving surface of the instruments with and without radiation incidence respectively. A comparison of data obtained through our preliminary experiment with those of the local meteorological stations shows that the difference is within 15%. 7. Study of the radiation heat transfer in a coverglass-absorber system. The problem of radiation heat transfer in a coverglass-absorber is of great importance in the use of solar energy and in the thermal design of building engineering. This study presents a method for calculating the solar energy absorbed by the absorber and transparent covers in the systems .with absorber and multilayer covers. We have made an analysis of the determination of the radiation heat loss of the absorber in the system consisting of an absorber and such a cover as has a significant transmittance in the infrared spectrum. The obtained formula for the calculation of radiation heat loss is easy to use. The physical meaning of the formula is also obvious. 8. Research on the measurements of the thermal radiation properties of the metals and coatings. (3,9,10) In cooperation with the Shanghai Institute of Ceramics Academia Sinica, we have studied the measurement of the thermal properties of the solids. Several apparatus are designed and constructed, among which are: an integrating sphere for measuring the directional-hemispherical spectral reflectance for various incidences, two simple apparatus for measuring the normal thermal emissivity of the metals and coatings, and an apparatus for measuring the hemispherical total emissivity. Now some new apparatus are going to be installed. The following investigations are being carried on now: 1) The measurement of the thermophysical properties of the phase change materials. 2) A study of the transient behavior of the latent thermal storage. 3) A design of the low plastic solar collector.
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