A system suitable for receiving, storing and supplying water, said system comprising: a tank having a first and a second outlets (10, 7) to supply water in the tank to a heat exchanger, and a first and a second inlets (7, 5) to return water heated by the heat exchanger to the tank, and a third inlet to introduce tap water to the tank, and a third outlet and fourth outlet (9, 11) to supply domestic hot water, and configured to hold water for domestic use, said tank comprising a bottom section, a top section and a middle section and configured to the first outlet and third inlet (10, 3) to be located in the bottom section, the first inlet, second outlet and fourth outlet to be located in the middle section, and the second inlet and the third outlet to be located in the top section, and a heat exchanger equipped with an inlet configured to receive water in the tank and an outlet configured to supply said water to the tank, a heating circuit configured to provide a fluid connection between the outlet of the heat exchanger and either the first inlet or the second inlet (7, 5), and configured to provide a fluid connection between the inlet of the heat exchanger and either the first outlet or the second outlet, the system, further comprising a plurality of diffusers comprising a first bowl shape diffuser and a second bowl shape diffuser, and the first bowl shape diffuser is located close to the bottom of the tank and so that an open side of the bowl is downwards and the axial direction of the first bowl shape diffuser is vertical, and the second bowl shape diffuser is located close to an upper wall of the tank and so that an open side of the bowl is upwards and the axial direction of the second bowl shape diffuser is vertical, and the first bowl shape diffuser is disposed to the third inlet and the second bowl shape diffuser is disposed in the second inlet. a tank having a first and a second outlets (10, 7) to supply water in the tank to a heat exchanger, and a first and a second inlets (7, 5) to return water heated by the heat exchanger to the tank, and a third inlet to introduce tap water to the tank, and a third outlet and fourth outlet (9, 11) to supply domestic hot water, and configured to hold water for domestic use, said tank comprising a bottom section, a top section and a middle section and configured to the first outlet and third inlet (10, 3) to be located in the bottom section, the first inlet, second outlet and fourth outlet to be located in the middle section, and the second inlet and the third outlet to be located in the top section, and a heat exchanger equipped with an inlet configured to receive water in the tank and an outlet configured to supply said water to the tank, a heating circuit configured to provide a fluid connection between the outlet of the heat exchanger and either the first inlet or the second inlet (7, 5), and configured to provide a fluid connection between the inlet of the heat exchanger and either the first outlet or the second outlet, the system, further comprising a plurality of diffusers comprising a first bowl shape diffuser and a second bowl shape diffuser, and the first bowl shape diffuser is located close to the bottom of the tank and so that an open side of the bowl is downwards and the axial direction of the first bowl shape diffuser is vertical, and the second bowl shape diffuser is located close to an upper wall of the tank and so that an open side of the bowl is upwards and the axial direction of the second bowl shape diffuser is vertical, and the first bowl shape diffuser is disposed to the third inlet and the second bowl shape diffuser is disposed in the second inlet.