Study of residential underfloor air distribution (UFAD) systems using a new modelling approach

Although single/multi-zone thermal models have their own advantages, like simple and fast computations of building energy demand, the accuracy of these models is problematic. The assumption of a uniform room temperature reduces the accuracy of the final energy demand results. In fact, the single/multi-zone thermal models are not able to predict indoor thermal behaviours or building energy demands accurately, if a non-uniform environment in a room or building is created by a single or multiple heating, ventilation, and air conditioning (HVAC) systems, i.e. an underfloor air distribution (UFAD) system. The research described in this article investigated the use of a new approach to improve the computational quality and accuracy of the heating energy demands of UFAD systems using an integrated zonal/multi-zone model. Several case studies were carried out, and the results demonstrate not only the advantages of UFAD systems used in a residential house in terms of energy saving, but also the importance of thermostat location in the prediction of building energy consumption. Additionally, the results indicate that the conventional single/multi-zone models are not appropriate to use for UFAD systems in the building energy demand predictions.