A tank of storage for the domestic hot water is warmed up often by the electricity via a heating element (heating of immersion).

For these tanks there are only two connections, one for the entrance of pipes and one for the plug of the hot water.

The thermal system to pave connects with these two ports and provides heat through them, normally via an external heat exchanger.

For the DHW unloading and a flow upper, the flow valve is closed, the water washes to heat exchanger and enters the warehouse at heart (superior figure).

In order to load of the tank, the flow valve is open and the water can register to the heat exchanger by the natural convection through the inferior connection and the hot water enters the warehouse in the cover (inferior figure).