Calculation of the heating and cooling load of buildings using a sky radiance distribution model

We present a model for calculating the sky radiation values considering the sky radiance distribution for a simulated building. We use the sky luminance distribution model of the CIE standard general sky rather than the measured sky radiance distribution. In this model, different sky types of the CIE standard general sky are identified from values of horizontal global sky radiation Eeg, and normal direct solar radiation Ees without reference to the measured sky radiance distribution. 
To evaluate the model, we calculated 1) the sky radiation values on east, west, north and south-facing vertical surfaces and 2) the annual heating/cooling load of a model room. Three sets of calculations were performed on the assumption of i) uniform sky, ii) measured sky radiance distribution, and iii) sky radiation model. The sky radiation model proposed in this study provides a better estimate of sky radiation values on vertical surfaces and heating/cooling load than estimates derived from a uniform sky model.