In the facilities where steam is used as a heating fluid, it is the storage where the steam, which leaves a large part of the heat to the system, rotates as a condensate from the system. Hot water is sent back to the boiler after the condensate tank. Since the system operates closed, there is no steam leakage to the external environment. Since the feed water to be sent to the boiler waits without losing its heat in the condensate tank, the amount of heat required to heat the water in the boiler is reduced. This saves fuel.