heat transfer

Both building performance and occupants' thermal comfort are influenced by heat conduction, convection and radiation as well as condensation/evaporation. This paper presents an analysis of thermal comfort in buildings subjected to simultaneous heat and moisture transfer using numerical techniques. A model based on computational fluid dynamics has been developed for predicting the indoor thermal environment. Assessment is made of the effects of radiation heat transfer and moisture condensation on the accuracy of predicted indoor thermal comfort.

This paper presents an analysis of different possibilities of representing mass transfers in zonal models. In this aim, formulations derived from the Navier-Stokes equations or from Euler's theorem are obtained. The models which result from them and empirical models are compared so that to define the best compromise between simplicity, accuracy and easy convergence.

This paper presents the results of a study aimed at quantifying the change in the U-factor caused by glass plate curvature in sealed, insulated glazing (JG) units. The curvature may be caused by a number of factors, two of which will be studied in this paper-barometric pressure and gas space temperature variations. In the first part of this paper, the equations governing glass plate deflections and heat transfer through JG units are briefly reviewed Then, glass plate deflections and the resulting change in the U-factor of several JG units are examined for ASHRAE-type winter conditions.

During the cooling season, heat transfer from the attic into the conditioned space of a residence can represent a significant portion of the total envelope heat transfer. Radiant barriers are one method used to reduce this heat transfer. A quasi-steady-state model was developed or predicting attic heat transfer in residences with radiant barrier systems. The model was used to estimate the reduction in cooling load that would occur with a radiant barrier and to identify important construction and environmental parameters that influence this cooling load reduction.

The attic space of most residential buildings is well insulated from the house below, and therefore experiences extreme temperature conditions on seasonal and diurnal cycles. This can cause moisture entering the attic through the ceiling from the house, or through other leaks from outside, to accumulate in or on interior wood surfaces. This moisture accumulation leads to structural degradation and the growth of micro-organisms.