In plants where steam is used as the heating fluid, it is the tank where the steam, which leaves most of the heat to the system, returns from the system as condensate water. After the condensate tank, hot water is sent back to the boiler.
Since the system is closed, there is no steam leakage to the external environment. Since the feed water to be sent to the boiler waits in the condensate tank without losing its heat, the amount of heat required to heat the water in the boiler is reduced. Thus, fuel saving is provided.