A 2-PORT ENVELOPE MODEL FOR BUILDING HEAT-TRANSFER

A zone envelope thermal model is derived from first principles, based on the exact two-port solution to the heat conduction equation. A sing le set of matrices, one for each frequency of interest, is used to des cribe the thermal behaviour of the total envelope. The set of matrices must be computed once for a particular zone and cooling loads for var ious conditions, or the passive response, can then be obtained. The me thod is based on the same principles underlying the CTF method. Howeve r, the transfer function is calculated for the whole envelope by combi ning the two-port matrices of the individual walls, after simplificati on of the room interior heat transfer network. The conduction transfer coefficients of the individual walls forming the zone are not require d. Except for the simplification of interior radiation, the method is completely exact and easy to implement. It is also numerically efficie nt. For load prediction, an implementation in the frequency domain, ba sed on the prime factor FFT algorithm is convenient. For time domain s imulation with active control, the envelope conduction coefficients ar e easily obtained by transforming to the Z-domain. This represents a m odern solution of the envelope conduction problem, which is convenient to implement in modern object oriented computer programming languages . 1998 Elsevier Science Ltd. All rights reserved.