Improving energy model calibration of multi-unit residential buildings through component air infiltration testing

Abstract

Building infiltration rates are one of the most uncertain parameters among multi-unit residential building (MURB) energy model inputs and have the potential to greatly impact building energy consumption. Infiltration rates exhibit high spatial and temporal variability and are highly building-specific making them difficult to estimate from published data. Reduction of parameter uncertainty using on-site measurements has traditionally been prohibitive, both from a cost and a logistical standpoint.Window component infiltration rate testing was conducted at two MURBs to develop component-weighted infiltration rates, which were input into whole-building energy models and compared with models that used a single building-level infiltration rate. The component-weighted infiltration rate allowed for the incorporation of building-specific measurements, which helped to reduce parameter uncertainty during model calibration. The component-weighted approach also helped to account for the variation in zone infiltration rates based on type and quantity of leakage paths. The discretization of the infiltration rate by building component can help during the modeling of energy retrofits that specifically target building infiltration, by setting bounds on the maximum possible improvement. Implementation of a component-weighted approach will help to improve model calibration and energy retrofit analysis in whole-building energy models, allowing owners and operators to make better-informed decisions regarding energy retrofits.