A DEVELOPMENT AND COMPARISON OF NAC ESTIMATES FOR LINEAR AND CHANGE-POINT ENERGY MODELS FOR COMMERCIAL BUILDINGS

The normalized annual consumption (NAC) index has proved useful in ene rgy analysis using the PRISM model. This paper develops NAC with rigor ous statistical error diagnostics for Linear and four-parameter change -point energy models. The models are applied to daily data from severa l case study commercial/institutional buildings, and the NAC estimates are analyzed and compared. The importance of goodness-of-fit for a mo del toward producing an accurate NAC estimate is examined. A new stati stic, NSR, designed to measure goodness-of-fit over temperature region s of long-term significance, is introduced and tested on the case stud y buildings.