The diurnal temperature variations of an object in an outdoor environment

A simple model is described for predicting the diurnal temperature changes of objects exposed to the outdoor environment, using standard weather parameters as input. The model consists of a differential equation with four source terms describing heating due to absorption of sunlight, heat transfer due to convection, radiative exchange with the sky and surroundings, and conduction from one part of the object to another. The mathematical expressions in these terms were kept as simple as possible, and the input data requirements were restricted to those which are experimentally attainable. The model has been validated by comparing the predicted temperatures of specimens made up of four aluminium plates to actual measured values, over three consecutive diurnal cycles. Results of the validation test show that the predictions were accurate to within a few Kelvin degrees of the actual temperatures, throughout the 72 h. © 1982 Butterworth & Co. (Publishers) Ltd