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Show Several different types of evaporative coolers include drip, air washers, two stage, slinger and rotary drum. The type of cooler is dependent upon the commercial or industrial application and cooling capacity. Other reuse systems include groundwater heat pumps. Shown in Figure 4, groundwater is pumped from a well though the cooling system heat exchanger and then injected back into the groundwater aquifer. Only the thermal value of the water is used, and there is no net water loss. These type of systems are used at the Church Office Building of The Church of Jesus Christ of Latter- day Saints in Salt Lake City and Utah Valley Community College in Orem. Status A review of the air conditioning and refrigeration industry found that almost all new installations of water operative cooling systems in Utah and many other states are the recycling type. This trend is apparently influenced by technology, regulations and economics. New once- through type systems are uncommon. In most cases, it is not considered good engineering practice to design or specify once- through type systems. Most once- through systems currently in service are very small. And many were installed as retrofits by building or facility owners. Since the useful life of cooling units ranges from 10 to 20 years, the use of once- through systems should continue to decrease through attrition. The regulation of air conditioning and refrigeration equipment is generally administered by city and county building departments. Most cities and counties in the state of Utah have adopted the Uniform Mechanical Code ( Code), without modification, as their standard for plan review and construction inspection. However, the code does not require recycling or reuse for water operative air conditioning and refrigeration . equipment. Out of seven Utah cities and counties contacted, only Salt Lake City has amended the code by local ordinance to require that new installations of water operative air conditioners " be equipped with evaporative condensers, cooling towers, spray ponds, or other approved water conservation equipment." Those still using once- through systems have resisted conversion by extending the life of existing equipment as long as possible to avoid the high capital cost of retrofitting with a system which conforms with the amended code. Besides local regulation, the use of recycling and reuse equipment in the industry is influenced by economic pressures. Increasing water and sewer rates have made recycling more attractive. Communities outside Utah have implemented regulations limiting the use of once- through systems for various reasons, including water conservation. For example, Nassau County, New York, passed an ordinance in 1987 requiring, among other things, that " All commercial and industrial water- operative air conditioning systems, refrigeration or other water- cooling equipment, ... be equipped with a water- recycling system." The ordinance was passed in an effort to minimize withdrawals from the surficial groundwater aquifer. A decline in the water table was responsible for serious environmental losses ( i. e. wetlands). Rather than restricting the use of specific equipment, the city of Phoenix, Arizona, has restricted the discharge of unpolluted water to the city's wastewater collection system. While effectively conserving water use, the ordinance was intended to minimize the amount of wastewater treated. Rather than mandating the use of recycling equipment, it allows the implementation of cooling water reuse for purposes such as irrigation. The city of San Jose, California, has taken a " carrot and stick" approach. It has adopted an ordinance similar to the one in Phoenix which 70 |