PURPOSE: To avoid a starting or stopping of an absorbing liquid pump and reduce variation of cold water discharging port temperature by a method wherein when a detected water level reaches a low water level, the number of revolution of the absorbing liquid pump is increased in reverse proportion to a counted time and when the water level reaches a high level, the number of revolution of the absorbing liquid pump is decreased in reverse proportion to the counted time.
CONSTITUTION: A period in which the surface of absorbing liquid in a regenerator ranges from a low water level to a high water level is counted. When the low water level is attained, the number of revolution of an absorbing liquid pump 8 is increasingly controlled in response to the period and in turn when the level becomes a high water level, the number of revolution of the absorbing liquid pump is decreasingly controlled in response to the period, thereby a lean absorbing liquid is sent to the regenerator in correspondence with an evaporating amount of the refrigerant at the regenerator, resulting in that a variation of the surface of the absorbing liquid at the regenerator 1 is reduced so as to restrict a starting or stopping of the absorbing liquid pump and then a heat exchanging between the lean absorbing liquid, rich liquid and intermediate liquid at the heat exchanger is continued and then a cold water outlet temperature can be supplied stably.
HITOMI KAZUHIRO
ISHIKAWA TAKEO
