Comparison between Current Industry Methods and an Energy Simulation Model for Quantifying Energy Service Projects

Abstract

Different techniques and guidelines are available to select and quantify the savings from energy service projects. In this article, a comparison is presented between the engineering algorithms supported by energy service performance contract technical reference manuals and an as-built, calibrated whole-building energy simulation model. A lighting energy retrofit measure was selected to demonstrate the methodologies. The results show that the industry methods of quantifying the total savings for the lighting energy retrofit measure underreported the savings as compared with the as-built, calibrated whole-building energy simulation model. In particular, the breakdown of savings (e.g., electricity savings, adjustments to energy savings, and demand savings) was inconsistent between the various industry methods that are currently in use. The differences identified in this study were location specific and weather driven, and also included agreements with the local utility companies to quantify the demand savings. The study results also indicate that substituting a single measured occupancy parameter did not improve the current industry methods.