A critical review on heat exchange coefficients between heated and cooled horizontal surfaces and room

Heating and cooling capacity of surface systems (floor, ceiling and walls) have been recently debated in the standards EN 1264 and EN 15377. Currently, there is no agreement on surface heat exchange coefficients between cooled floor and room at higher temperature and heated ceiling and room at lower temperature. Literature reports different equations, based on measurement procedures or on detailed calculations. In this paper a critical review on convective heat exchange coefficients is presented and available expressions for calculating these coefficients for heated ceiling or cooled floor are presented. The present work represents the first step of a research plan aiming at determining the performance of radiant systems based on measurements in a test room. The determination of convective heat exchange coefficients is also of great help in building simulation, due to their interesting use in practice.