AT-90-26-3 -- Short-Term Energy Monitoring - Summary of Results From Four Houses PDF

A technique called PSTAR (Primary and Secondary Terms Analysis and Renormalisation) is presented that analyses the building load coefficient, the effective heat capacitance, and solar gains obtained from short term test data taken on four houses. These are compared with the values from an audit description. In general, the audit description tends to overestimate the load coefficient and solar gains, sometimes quite seriously. The heat capacitance is sometimes overestimated and sometimes underestimated. The combined impact of the discrepancies between audited and measured characteristics on annual and peak loads is, quite often, serious. The audit values differ from actual for three possible reasons - (1) auditor errors, (2) uncertainties in material properties and hidden features, and, (3) errors in simulation models. Auditor errors have been greatly reduced in this study by having highly skilled personnel prepare audit descriptions. The importance of measurement-based performance assessment emerges from this study.

KEYWORDS: monitoring, housing, energy auditing, heat-load, solar heat gain, thermal capacity, measuring, comparing, calculating, performance.