A number of gas cooling products are making inroads in the marketplace. The three basic types of gas cooling equipment are engine-driven chillers, absorption chillers and desiccant dehumidifiers. Engine-driven chillers use a gas engine rather than an electric motor to drive a compressor. These systems are particularly attractive because they offer the option of recovering waste heat that can be used to generate hot water or steam. Sales of commercial gas engine-driven chillers jumped from 7,000 tons in 1994 to almost 50,000 tons in 1996.
Absorption cooling produces a cooling effect by evaporating a refrigerant.
These systems, which use water or ammonia rather than a synthetic refrigerant, commonly are used to cool large commercial buildings such as hotels, offices and hospitals. Gas-based desiccant dehumidification systems reduce humidity in commercial establishments, thereby reducing the energy required for cooling. When humid air is cooled, about half the energy of conventional cooling systems is actually used just to dry the air. Desiccants dry the air prior to cooling. The clean, dry air produced by desiccants can eliminate frost buildup in the frozen-food section of supermarkets, reduce airborne spores and bacteria in hospitals, prevent mold and mildew problems in hotels, and improve indoor air quality in offices and retail establishments.