Energy costs typically account for 10% to 20% of the operating costs for commercial buildings. These costs have continued to rise over the past several years notwithstanding the implementation of energy conservation programs. Increasing electric demand charges have been a major cause of the problem, and as capital-intensive nuclear and coal plants under construction are rolled into the rate base, these demand penalties are likely to become more severe. Electric cooling is the major contributor to seasonal and daily electric peaks.

The use of natural gas for cooling can provide relief from high peak period electric prices either directly through absorption systems and engine-driven chillers or indirectly via cogeneration and recovered heat-driven adsorption cooling. In the case of a San Diego utility, the inducement is in the form of a capacity credit and is applicable to gas cooling in addition to cold storage. These capacity credits should easily offset any first cost premium for gas cooling equipment.

Although a window of opportunity exists for gas cooling in some parts of the country today, technological advancement and cost reduction are required in order for gas cooling to realize widespread applicability. The Gas Research Institute has implemented a comprehensive development program in cooperation with industry to evolve engine-driven chiller systems in the 100-ton and larger size range with gas coefficients of performance of 2.4, first-cost premiums of less than $100/ton, and service intervals of 4000 hours. Maintenance records of several engine-driven systems installed in the early 1970s were studied. System reliability was found to be in-line with HVAC market requirements.

The positive outlook for natural gas supply and price coupled with projected progress on the R&D front, is expected to result in competitive economics for gas-fueled cooling throught this century.

Achievement of engine chiller cost and performance goals, coupled with a positivve outlook for natural gas supply adn price, should result in competitive economics for gas cooling equipment throughout the foreseeable future.

Units: I-P