ON THE INVERSE TRANSIENT HEAT-TRANSFER PROBLEM IN STRUCTURAL ELEMENTS EXPOSED TO SOLAR-RADIATION

The inverse transient heat-transfer problem in walls, whether or not exposed to solar radiation, i.e. the estimation of the thermal properties of a wall if the transient temperature and/or heat flow fields are known, is interesting both from the theoretical and practical point of view. An attempt is made to analyse and solve this problem. Methods are developed for estimating the thermal properties of structural elements which are already parts of existing buildings, i.e. under real transient, non-periodic conditions. The finite-difference and experimental examples presented show that the thermal diffusivity, the thermal conductivity and the overall heal transfer coefficient may be estimated with very good accuracy by taking on-site temperature and heat flow measurements.