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A ceiling fan is a mechanical fan, usually electrically powered, suspended from the ceiling of a room, that uses hub-mounted rotating paddles to circulate air. A ceiling fan rotates much more slowly than an electric desk fan; it cools people effectively by introducing slow movement into the otherwise still, hot air of a room, inducing evaporative cooling. Fans never actually cool air, unlike air-conditioning equipment, but use significantly less power (cooling air is thermodynamically expensive). Conversely, a ceiling fan can also be used to reduce the stratification of warm air in a room by forcing it down to affect both occupants' sensations and thermostat readings, thereby improving climate control energy efficiency. ==History== The first ceiling fans appeared in the early 1860s and 1870s, in the United States. At that time, they were not powered by any form of electric motor. Instead, a stream of running water was used, in conjunction with a turbine, to drive a system of belts which would turn the blades of two-blade fan units. These systems could accommodate several fan units, and so became popular in stores, restaurants, and offices. Some of these systems still survive today, and can be seen in parts of the southern United States where they originally proved useful. The electrically powered ceiling fan was invented in 1882 by Philip Diehl; he had engineered the electric motor used in the first electrically powered Singer sewing machines, and in 1882 adapted that motor for use in a ceiling-mounted fan. Each fan had its own self-contained motor unit, with no need for belt drive. He was almost immediately up against fierce competition due to the commercial success of the ceiling fan. He continued to make improvements to his invention; by creating a light kit fitted to the ceiling fan to combine both functions in one unit. By World War I most ceiling fans were made with four blades instead of the original two, which made fans quieter and allowed them to circulate more air. By the 1920s ceiling fans had become commonplace in the United States, and had started to take hold internationally. From the Great Depression of the 1930s until the introduction of electric air conditioning in the 1950s ceiling fans slowly faded out of vogue in the U.S.,〔 almost falling into total disuse in the U.S.; those which remained were considered items of nostalgia. Meanwhile, they had become very popular in other countries, particularly those with hot climates such as India but without the infrastructure or financial resources for high-energy-consuming and complex freon induced air conditioning equipment. In 1973, Texas entrepreneur H.W. (Hub) Markwardt began importing highly efficient ceiling fans to the United States that were manufactured in India by Crompton-Greaves, Ltd. Crompton-Greaves had been manufacturing ceiling fans since 1937 through a joint venture formed by Greaves Cotton of India and Crompton-Parkinson of England, and had perfected the world's most energy efficient ceiling fans thanks to its patented 20 pole induction motor with highly efficient heat-dissipating cast aluminum rotor shell. These Indian manufactured ceiling fans caught on slowly at first, but Markwardt's Encon Industries branded ceiling fans (ENergy CONservation) eventually found great success during the energy crisis of the late 1970s and early 1980s, since they consumed far less energy (under 70 watts of electricity) than the antiquated shaded pole motors used in most other American made fans, and far more efficient than using expensive air conditioning units. Due to this renewed commercial success using ceiling fans effectively as an energy conservation application, many American manufacturers also started to produce, or significantly increase production of, ceiling fans. In addition to the imported Encon ceiling fans, the Casablanca Fan Company was founded in 1977. Other American manufacturers of the time included the Hunter Fan Co. (which was then a division of Robbins & Myers, Inc), FASCO (F. A. Smith Co.), Emerson Electric, and Lasko; the latter two were often branded as Sears-Roebuck. Through the 1980s and 1990s, ceiling fans remained popular in the United States. Many small American importers, most of them rather short-lived, started importing ceiling fans. Throughout the 1980s the balance of sales between American-made ceiling fans and those imported from manufacturers in India, Taiwan, Hong Kong and eventually China changed dramatically with imported fans taking the lion's share of the market by the late 1980s. Even the most basic U.S-made fans sold at $200 to $500, while the most expensive imported fans rarely exceeded $150. Since 2000 important inroads have been made by companies offering higher price ceiling fans with more decorative value. In 2001, Washington Post writer Patricia Dane Rogers wrote, “Like so many other mundane household objects, these old standbys are going high-style and high-tech.” 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「ceiling fan」の詳細全文を読む スポンサード リンク
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