A heat and mass transfer analysis of the subfloor cavity of a residential building
Authors: Sequeira, Sabrina ; Chen, Dong ; Fay, Roger; Sargison, Jane ; Soriano, Florence
As roof and wall insulation have become a standard inclusion in a residential building’s design, the
conditions in the subfloor cavity have gained relative importance to the building’s thermal performance.
However, the modelling of heat and mass transfer between a building and the ground is considered a
weak point in many building simulation programs. As very little measured data on Australian subfloor
conditions exists, this research seeks to investigate the subfloor conditions experimentally. This paper
examines measured subfloor climate data and compares it to acceptable limits and prior field studies.
Heat and mass transfer relationships connecting subfloor ventilation, ground evaporation and the
subfloor and outdoor climate conditions are developed theoretically and investigated using measured
data. Ground evaporation is found to have a significant effect on the energy balance in the subfloor.
Thus a recommendation is made to include an evaporation model in Australia’s AccuRate building
thermal performance simulation program.