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Show Requirements for the installation of water recycling or reuse systems on any newly installed commercial and industrial water- operative air conditioning and refrigeration systems. Public Law 102- 575, Subsection 207( f)( 2)( H) i Background Water operative air conditioning systems are commonly used for a number of commercial and industrial applications, including office buildings, hotels, schools, hospitals, warehouses and supermarkets. Water operative refrigeration systems are found in supermarkets, ice makers, restaurants, and other food storage or freezer facilities. Types of Systems Water is used in many commercial and industrial air conditioning and refrigeration systems to remove heat extracted by the cooling equipment. Three main types of water operative air conditioning/ refrigeration systems are once- through, recycling and evaporative. The once- through system is illustrated in Figure 1. Cool water from a distribution system is directed through a heat exchanger, and heat from the process is transferred to the water. The process may be a refrigeration system such as an ice maker or an air conditioning system. Heat from a refrigeration system is transferred from the refrigerant to the water whereas heat from an air conditioning system might be transferred from the air being cooled. The heated water is then discharged to the sanitary sewer or storm drain system. The process might also be a water cooled system where heat 1 is transferred directly from the air to the circulating water. The recycling type cooling system, shown in Figure 2, is similar to the once- through system, except water is recirculated and/ or reused for other purposes rather than discharged to waste. After passing through the heat exchanger, the warm water is cooled by evaporation in a cooling tower and returned once again to the heat exchanger. Some water is consumed by evaporation, and minerals left behind become concentrated in the remaining water. To prevent scaling in the equipment, this mineralized water must be bled off or " blown down" and replaced with fresh water. The water lost to evaporation is also replaced. The replacement water is called " make- up water." As an alternative to " blow down" flushing of minerals, chemical treatment systems increase the number of recycles are also currently available. Evaporative coolers, depicted in Figure 3, are generally used where the entire air stream to be cooled is supplied from outdoors, such as in a warehouse. Evaporative coolers are used to increase humidity and decrease temperature. They operate by lowering the air's dry bulb temperature when water vapor is absorbed. |
