Measuring Retrofit Savings in Commercial Buildings with Pre-Retrofit Utility Billing Data and Post-Retrofit Sub-Metered Data

Abstract

Methodologies to measure energy and dollar savings resulting from energy conserving retrofits in commercial buildings when both pre-retrofit and post-retrofit monitored data are available at an hourly or daily level have already been developed by several researchers. However there are many occasions when hourly or daily energy consumption data are available only for the post-retrofit period. This thesis presents a methodology for measuring retrofit savings on such occasions by establishing a pre-retrofit baseline model of energy consumption based on pre-retrofit monthly utility billing data and sub-metered daily or hourly post-retrofit data. The procedure consists of two basic parts. The first part normalizes energy use for temperature dependency using post-retrofit sub-metered hourly data, the second part accounts for scheduling effects and develops a pre-retrofit baseline model using pre-retrofit utility bills. In this way, the method explicitly accounts for both scheduling and weather effects in developing a baseline for pre-retrofit energy consumption. The methodology is first tested with data from a LoanSTAR site where both pre- and post-retrofit data are available. It is then illustrated with two other LoanSTAR sites where only post-retrofit sub-metered data and pre-retrofit monthly utility billing data are available. This thesis also employs the direct utility bill comparison method to measure retrofit savings, and extends it to include a simple temperature comparison and compares results on a monthly and annual basis with the method developed herein.