Cooling-Only Prism Analysis of Eleven College Station Homes and Interpretation of Building Physical Parameters

Abstract

A cooling-only PRISM analysis has been performed on eleven new residences in College Station using electricity billing data over an entire year. This study revealed that, provided one corrects for effects such as vacation periods, erroneous utility meter readings and abnormal occupancy patterns during holiday periods, the PRISM approach can accurately model whole-building electricity use (R^2 in the range of 0.92 to 0.99). The physical interpretation of the building parameters determined by PRISM has also been evaluated against continuous measurements of indoor temperature and air-conditioned electricity consumption made during the summer as part of another study. We find that the PRISM estimates for balance point temperature are within a few degrees of actually "measured" values and seem to be unbiased. The PRISM estimates for base-load consumption. on the other hand, are consistently higher by 50% to 100% of the measured base-loads, and factors which may contribute to this bias have also been briefly discussed.