- 上一篇：冲压级进模英文文献和中文翻译
- 下一篇：空调节能技术的研究英文文献和中文翻译
Different air conditioners use various amounts of electricity to remove the same amount of heat. Engineers use a number, called the Energy Efficiency Ratio (EER), to measure how economically an air conditioner uses electricity. To find an air conditioner's EER, its Btu per hour rating is pided by the number of watts of electricity used by the unit. For example, an air conditioner that uses 600 watts to remove 5,000 Btu's per hour has an EER of 5,000 pided by 600, or 8.33. Most air conditioners have an EER of from 8 to 9. The higher the EER of a unit, the less electricity it uses--and the less it costs to operate.
History
The ancient Egyptians, Greeks, and Romans used wet mats to cool indoor air. They hung the mats over the doors to their tents and other dwellings. When wind blew through the mats, evaporation of the water cooled the air. The people of India later used this method to cool the royal palaces. About 1500, Leonardo da Vinci, the great Italian artist and scientist, built the first mechanical fan to provide ventilation. Water power turned the fan. In 1553, the English developed a rotary fan to ventilate mines.
Textile manufacturers made the first attempts at air conditioning. In 1719, a silk company in Derwent, England, installed a central system to heat and ventilate its mill. Early cloth makers in New England boiled water in huge pots near their looms to keep the air moist. Unfortunately, the heat injured the health of the workers and this method was discontinued.
About 1838, David B. Reid, an English scientist, provided the British House of Commons with a system to ventilate and humidify the air. In the mid-1800's, John Gorrie, an American, invented a cold-air machine to cool hospital rooms.
During the late 1800's, textile manufacturers in New England began using sprays of water to condition the air in their mills. In 1897, Joseph McCreery of Toledo, Ohio, received a patent for the type of spray now used in air conditioners.
By 1902, Alfred R. Wolff, a consulting engineer, had designed air-cooling systems for Carnegie Hall and several other buildings in New York City. That same year, Willis H. Carrier, a research engineer, designed the first scientific system to clean, circulate, and control the temperature and humidity of air.
In 1906, Stuart W. Cramer, a textile engineer from Charlotte, N.C., used the term air conditioning for the first time. Air conditioning became a recognized branch of engineering in 1911.
The Baltimore & Ohio Railroad installed the first air-conditioning system for trains in 1931. Air conditioning of apartments and homes also began during the 1930's. In 1939, Packard Motors introduced air-conditioning units for automobiles. The Greyhound Corporation installed the first bus air-conditioning systems in 1940. By the 1990's, about 70 percent of all of the housing in the United States had some form of air conditioning. In addition, most of the new single-family homes that were built in the United States were equipped with central air conditioning.
Careers in air conditioning
Careers in air conditioning can be pided into five main fields: (1) designing, (2) manufacturing, (3) selling, (4) installing and servicing, and (5) teaching and research. College-educated engineers research and design air-conditioning systems. Skilled machinists, toolmakers, cabinetmakers, and similar craftworkers help manufacture air conditioners. Technical training, such as a degree in engineering, is often essential for positions in the selling and executive branches of air conditioning. Specially trained technicians, and operating and service engineers, install and maintain air conditioners.
Contributor: James E. Hill, Ph.D., Chief, Building Environment Division, National Institute of Standards and Technology.
空气调节就是控制温度、湿度、清洁度和室内空气的流动。当天气热的时候，它冷却空气制冷；当天气冷的时候，它加热空气制热。舒适度部分是靠湿度完成的，并且空调在需要的时候会去除空气中的湿气或者增加湿气，去除空气中的污尘使得空气更加健康清新。通过控制空气的流动，空调把新鲜的空气送入房间并且把污浊的空气排出室内。通过所有的这些方式，空调为人们提供新鲜空气使得人们可以舒适地工作玩乐，即使是在睡觉的时候也能如此。论文网