Abstract
A new type of hot water boiler for domestic use is deviced. The boiler, a vertical cylinder 500 mm in diameter 1300 mm in hight 200 Z in volume, is heated by coal which is fired in a cylindrical pot placed at the center of the bottom of the boilor. Combustion gas goes upwards through smoke tubes and is exchausted to a chimney. About 3 kg of coal is burned in one time and water is heated from about 20°C to 80°C, then the hot water is used until it is almost replaced by the cold water. As the result of experments, it is shown that the thermal efficiency of the boiler is of 67-82% and heating time is about 1 hour.
