Calculating building heating and cooling loads using the frequency response of multilayered slabs

The development of a method for calculating room heating and cooling loads using frequency response methods to calculate heat flow through multi-layered room walls and roofs is discussed. Existing methods for calculating room loads are discussed and the need to consider the effects of thermal mass are emphasized. A detailed derivation of the solution of the transient one-dimensional heat conduction equation for multi-layered slabs which leads to the calculation of response factors and conduction transfer functions is presented. Next, the special case of a fixed temperature on one side of a multi-layered slab and a sinusoidal temperature variation on the other side is examined and the simplifications which result are described. The use of this simplified method for calculating room heating and cooling loads allows building energy analysis procedures to be implemented on microcomputers.