Economic Analysis of Packaged Engine-Driven Rooftop Gas Air Conditioners

The objective of this study was to perform a comparative economic analysis for packaged engine-driven gas rooftop air conditioners versus competing electric rooftop equipment for office and retail applications using a detailed energy analysis.  Gas air conditioners (GAC) utilize a direct drive, variable speed, natural gas driven engine-compressor package with good part load efficiency.  In many cities, the GAC had lower annual operating costs compared to electric units.  Gas cooling rebates, available through gas utility and/or electric demand-side management programs in many cities, can offset the initial cost premium of the GAC to give favorable paybacks.  This project established the competitiveness of the GAC in 49 U.S. cities and estimated national sales potential.