Water heater and flow rate control method

摘要

A water heater in which by applying pulsation of a liquid to be heated which circulates between a tank and a heat exchanger, scale that has been deposited on the inner wall (heat-transfer surface) of a to-be-heated liquid flow channel in a heat exchanger is detached, and the number of times of circulation of the liquid to be heated which circulates between the tank and the heat exchanger is controlled to be three times or less. The number of times of circulation is determined, based on the entire volume of the to-be-heated liquid stored in the tank, a boiling time to be taken for the entire volume of the to-be-heated liquid in the tank to reach a predetermined temperature, and the flow rate of the to-be-heated liquid which passes through the to-be-heated liquid flow channel.

主权项

1. A water heater comprising:
a tank which stores a liquid to be heated; a heater disposed midway in a to-be-heated liquid piping to form a flow channel through which the to-be-heated liquid flown out from the tank flows into the tank again, the heater including a heating flow channel, the to-be-heated liquid flown out from the tank into the to-be-heated liquid piping flowing into the heating flow channel where a temperature of the to-be-heated liquid is increased, and then the to-be-heated liquid being flown into the to-be-heated piping on an inlet side of the tank; and a distribution control unit which distributes the to-be-heated liquid stored in the tank into the to-be-heated liquid piping, wherein the distribution control unit controls a flow rate of the to-be-heated liquid which passes through the heating flow channel of the heater, thereby pulsating, within a boiling time, the to-be-heated liquid which circulates through the flow channel including the tank and the heater, and which passes through the heating flow channel of the heater, wherein the boiling time being set as a time to be taken for an entire volume of the to-be-heated liquid to reach a predetermined temperature, and wherein the distribution control unit controls the flow rate of the to-be-heated liquid which passes through the heating flow channel of the heater so that the entire volume of the to-be-heated liquid stored in the tank passes through the heater a predetermined number of times or less within the boiling time.