A heating installation comprising: a first circuit (C1); a second circuit (C2); a first heat pump (4) for heating the medium in the first circuit; a first heat exchanger (10) arranged in the second circuit (C2) and connected between a condenser (4b) and an expansion valve (4d) of the first heat pump; a second heat pump (11) arranged for heating a medium by absorbing heat energy from the medium in the second circuit; and a second heat exchanger (12) and a third heat exchanger (14) for transferring heat from the medium in the second circuit to water in a water supply line (13). The second heat exchanger (12) is connected to the water supply line upstream of the third heat exchanger (14) in order to allow the second heat exchanger to preheat the tap hot-water in a first step and the third heat exchanger to preheat the tap hot-water in a subsequent second step.

Provided is a heat source device including a control unit which, in response to a predetermined request for heating, sets a switching valve to a first circulation mode to communicate first and third ports, whereas to cut off communication between second and third ports, and performs a heating operation by actuating a burner and a circulation pump. In response to a predetermined request for hot water supply, the control unit sets the switching valve to a second circulation mode to communicate second and third ports, whereas to cut off communication between first and third ports, and performs a hot water supply operation, by actuating the burner and the circulation pump. A hot water supply stop alarm unit issues a hot water supply stop alarm that urges a user to stop using hot water when the request for heating is continued for a first predetermined time or more.

A heat exchanger including more than one fluid conductor, each of the fluid conductors is configured to receive a distinct flow of fluid and heat from only one heat source, wherein the coils are configured to be interleaved to form a structure of a single-sized lumen in which the heat source is disposed.

A heating device with hot water supply function includes: a combustion means; a first heat exchanger; a circulation passage that connects the first heat exchanger and an room heating unit; a circulation pump; a bypass passage that branches off from the circulation passage; a second heat exchanger for hot water supply provided in the bypass passage; a cold water supply passage; a hot water supply passage for supply of hot water from the second heat exchanger; and a distribution means that is provided at a branching section and whose distribution ratio can be adjusted, so that it becomes possible selectively to execute either only room heating operation, or only hot water supply operation, or simultaneous room heating operation and hot water supply operation; wherein the hot water supply outlet, the thermal medium inlet, and the room heating outlet of the distribution means are at the same height.

A combined water heating, space heating and space cooling system configured to provide hot water to a point of demand and heat or cool a space. The system comprises a heat pump operably connected to the space, a water flow loop including a main heat exchanger, a fluid mover for moving a fluid configured to flow within the flow loop, an air-to-water heat exchanger, a burner adapted to heat the fluid, a blower having an air inlet end and an air outlet end, wherein the blower is adapted to move air through the air-to-water heat exchanger and operably connected to the main heat exchanger and a secondary heat exchanger operably connecting the flow loop and the heat pump. The air-to-water heat exchanger is disposed on the air inlet end and the main heat exchanger is disposed on the air outlet end.

A heating device with hot water supply function includes: a combustion means; a main heat exchanger; a circulation passage connecting the main heat exchanger to an heating apparatus; a circulation pump provided in the circulation passage; a bypass passage that branches off from the circulation passage and bypasses the room heating apparatus; a secondary heat exchanger provided in the bypass passage; a cold water supply passage for supplying cold water to the secondary heat exchanger; a hot water supply passage for supplying hot water heated by the secondary heat exchanger; a hot water supply bypass passage that connects the cold water supply passage to the hot water supply passage bypassing the secondary heat exchanger; a flow adjustment means for adjusting the flow rate in the hot water supply bypass passage and thereby controlling the temperature of hot water to be supplied; and an expanded passage portion of the hot water supply passage whose diameter is increased from an intermediate portion of the hot water supply passage to its downstream end.

Provided is a heat source device including a control unit (51) which, in response to a predetermined request for heating, sets switching valve (21) to first circulation mode to communicate port (21a) and (21c), whereas to cut off communication between port (21b) and (21c), and performs heating operation by actuating burner (11) and circulation pump (22). In response to a predetermined request for hot water supply, the control unit (51) sets the switching valve (21) to second circulation mode to communicate ports (21b) and (21c), whereas to cut off communication between ports (21a) and (21c), and performs hot water supply operation, by actuating burner (11) and circulation pump (22). A hot water supply stop alarm unit (52) issues a hot water supply stop alarm that urges a user to stop using hot water when the request for heating is continued for a first predetermined time or more.

A system for heating water includes a circuit (2) in which an operating fluid circulates; the circuit (2) having a means (20) for heating the operating fluid. A first line (31) supplies water for sanitary use and a second line (32) supplies water intended for heating at least one environment of a building. A first heat exchange means (5) exchanges heat between the circuit (2) and the first supply line (31) and second heat exchange means (4) exchanges heat between the circuit (2) and the second supply line (32). The heating means (20) has or is a piston pump (21).

To reduce remaining air bubbles, a space and water heating apparatus includes external and internal circulation channels, including a shared portion, to respectively circulate a heating medium through space heating equipment and a water-heating heat exchanger, a discharger that discharges air bubbles, and a circulation switcher (three-way valve) that switches among a space heating operation mode, a water heating operation mode, and a simultaneous operation mode to respectively circulate the heating medium along the external circulation channel, the internal circulation channel, and both the external and internal circulation channels. Feeding the heating medium is followed by a test operation including external- and internal-channel discharge processes to respectively discharge air bubbles from the external and internal circulation channels by circulating the heating medium. In the internal-channel discharge process, the water heating or simultaneous operation mode is switched to the space heating operation mode during operation of a circulation pump.

A water heater system including a boiler having a heat exchanger and an indirect water heater having a heat exchanger, and a controller configured to activate a pump such that the water flows between the boiler heat exchanger and the indirect water heater heat exchanger, and to control a heat source to provide heat to the boiler at a firing rate. The water heater system measuring temperatures of the water at the boiler water inlet and at the boiler water outlet, calculating an amount of heat transfer from the boiler heat exchanger to the indirect water heater exchanger based on the measured temperatures, and adjusting the firing rate based on the calculated amount of heat transfer to determine a heat transfer capacity of the indirect water heater exchanger.