ABSTRACT
The properties of a parameter, ε (0 ≤ ε ≤ 1), defined as “coefficient of performance”, able to characterize the distribution of thermal resistance and heat capacity in the external walls of buildings, are discussed in some simple but significant situations. In a multi-layer wall, the sequence of layers which facilitates the air-conditioning plant, in order to keep the indoor air temperature constant, is the one characterized by the highest value of ε. The most convenient calculation methods are indicated for the coefficient of performance evaluation in case of walls commonly used in building.
