Air conditioning has rapidly grown over the past 50 years, from a luxury to a standard system included in most residential and commercial buildings. In 1970, 36% of residences in the U.S. were either fully air conditioned or utilized a room air conditioner for cooling (Blue, et al., 1979). By 1997, this number had more than doubled to 77%, and that year also marked the first time that over half (50.9%) of residences in the U.S. had central air conditioners (Census Bureau, 1999). An estimated 83% of all new
homes constructed in 1998 had central air conditioners (Census Bureau, 1999). Air conditioning has also grown rapidly in commercial buildings. From 1970 to 1995, the percentage of commercial buildings with air conditioning increased from 54 to 73% (Jackson and Johnson, 1978, and DOE, 1998).
Air conditioning in buildings is usually accomplished with the use of mechanical or heat-activated equipment. In most applications, the air conditioner must provide both cooling and dehumidification to maintain comfort in the building. Air conditioning systems are also used in other applications, such as automobiles, trucks, aircraft, ships, and industrial facilities. However, the description of equipment in this chapter is limited to those commonly used in commercial and residential buildings.
Commercial buildings range from large high-rise office buildings to the corner convenience store. Because of the range in size and types of buildings in the commercial sector, there is a wide variety of equipment applied in these buildings. For larger buildings, the air conditioning equipment is part of a total system design that includes items such as a piping system, air distribution system, and cooling tower. Proper design of these systems requires a qualifie

過去 50 年以來，空調得到了快速的發(fā)展，從曾經的奢侈品發(fā)展到可應用于大多數(shù)住宅和商業(yè)建筑的比較標準的系統(tǒng)。在 1970 年的美國， 36% 的住宅不是全空氣調節(jié)就是利用一個房間空調器冷卻；到1997年，這一數(shù)字達到了 77%，在那年作的第一次市場調查表明，在美國有超過一半的住宅安裝了中央空調 (人口普查局, 1999)。在1998年，83%的新建住宅安裝了中央空調 ( 人口普查局, 1999)。中央空調在商業(yè)建筑物中也得到了快速的發(fā)展，從 1970年到1995年，有空調的商業(yè)建筑物的百分比從54%增加到 73%(杰克森和詹森,1978)。