Infiltration Modeling

Abstract

Infiltration can be broken down into a climate independent component (ELA), and another dependent on climate conditions, in a non-lineal effect. The climate independent component can be partially quantified by the field tests, whilst the climate interaction requires of a model to calculate its effect. The ASHRAE's [6] recommended Lawrence Berkeley Laboratory (LBL) have been used for this purpose. This model establishes that air infiltrations are a function of permeability of the building and the pressure differences through its envelope. These pressure differences are induced by air temperature differences (Stack effect) and the wind's pressure. The above-described methodology has been implemented in TRNSYS, considering weather and monitored data , with the aim of achieving transitory infiltration values , and the determination of the effect of air leakage in the buildings' thermal behaviour. Results and discussion The exposed methodology has only been implemented in three of the four buildings originally selected. In the remaining one, although the air leakage test was tried, the required pressure differential values (50 Pa) were not achieved due to the construction pathologies. Both the influence of the pathologies in the building envelope and the ones in the internal partitions adjacent to un-conditioned spaces posed too high an obstacle for the consecution of reliable results.