Domestic combined heat and power system

A domestic combined heat and power system comprising a power unit, a heat-storage tank which receives waste heat of the power unit and stores heat in direct water separately flowing in, and a main heat exchanger which is connected to the heat-storage tank and is heated by a burner so as to use water as hot water or heating water,

• wherein a waste-heat heat exchanger filled with a heat-transfer medium is installed between the power unit and the heat-storage tank, such that a waste-heat pipe of the power unit is arranged in the form of a coil at one side inside the waste-heat heat exchanger, and a heat-storage pipe of the heat-storage tank is arranged in the form of a coil at the other side, so that heat is indirectly exchanged from waste heat of the power unit to the heat-storage tank through the heat-transfer medium;
• a heating-water supply pipe coming out from the heat-storage tank comes back into the heat-storage tank via a main heat exchanger, a third three-way valve, a heating load, a second three-way valve, and a first three-way valve, another outlet of the first three-way valve is connected to the heating-water supply pipe that comes into the main heat exchanger, and a hot-water-heating heat exchange coil coming out from another outlet of the third three-way valve is arranged so as to allow indirect heat exchange with a heat exchange coil of hot-water piping at a hot-water heat exchanger, and then connected so as to come into another inlet of the second three-way valve, and
• the hot-water piping coming out from the heat-storage tank is arranged so as to be indirectly heat exchanged with the hot-water-heating heat exchange coil at the hot-water heat exchanger, and then connected to a hot-water valve side.