Improved data correlations for buoyancy-driven convection in rooms

Improved data correlations have been derived for buoyancy-driven convective heat transfer from the internal surfaces of naturally-ventilated buildings. They cover the full range of laminar, transitional and turbulent airflows, and are based on the mathematical model of Churchill & Usagi (1972). The new correlating equations are presented in a convenient form for incorporating into modern computer programs which simulate the dynamic thermal performance of buildings. They compare favourably with the available exerimental data for isolated surfaces, and are shown to be an improvement on the ‘standard’ correlations recommended in the CIBS Guide. The factors which affect the accuracy of such data correlations, when used for the energy-conscious design of ‘real’ buildings, are briefly discussed.