Room heat needs in relation to comfort temperature: Simplified calculation methods

Abstract

Definitions are set up of local and space-averaged air and radiant temperatures and certain derived temperatures, together with the conductances that are needed to estimate building heat needs. Expressions are derived for the radiant and convective heat inputs Qr and Qa which are needed to establish a particular value of comfort temperature; they are given for each of three models for room internal heat exchange. They are easy to derive and simple to state. The method currently advanced in the CIBSE Guide (Section A5) to compute these needs is summarised: quite apart from the fundamental flaws in its basis, its exposition is more protracted and convoluted than is necessary.