近年来,日本的热水器的使用和生产发展很快。目前生产太阳能热水器的工厂约有20多家,其中有不少有名的大企业,如川崎重工、三菱、矢崎部品、日立化成、日本电气硝子公司。产品有平板式和玻璃真空管式两类。玻璃真空管集热器目前多用于集体单位的冷暖房。各工厂生产的真空集热管的尺寸不完全相同,一般长度为1400～2000毫米,最长的达 In recent years, the use and production of water heaters in Japan have developed rapidly. At present, there are about 20 factories producing solar water heaters, among which many famous large enterprises, such as KHI, Mitsubishi, Yazaki Parts, Hitachi Chemical, and Nippon Electric Glass. Products are flat and glass vacuum tube two types. Glass vacuum tube collectors are currently used for collective units of the heating and cooling room. The size of the vacuum tube of each factory production is not exactly the same, the general length of 1400 ~ 2000 mm, the longest up to