A hot water circulation system comprises a water heater having a cold-water inlet and a hot water outlet. A water pump circulates water through the water heater to produce hot water. The hot water is circulated to a thermal bypass valve, which is configured to close when hot water contacts a heat activated seal. A bypass circuit is coupled between the hot water outlet and the cold water inlet of the water heater. The bypass circuit prevents hot water from circulating from the hot water outlet to the cold-water inlet when the thermal bypass valve is open and promotes circulating hot water from the hot water outlet to the cold water inlet when the thermal bypass valve is closed. Upon a temperature sensor sensing hot water entering the cold-water inlet, the water heater turns of the water pump.

A heater with a recovery device for swelling water is provided. A water inlet pipe and a water outlet pipe are longitudinally provided on the heater. The recovery device is transversely disposed on the heater and connected with the water inlet pipe, such that the recovery device is coupled on to reduce the entire size. The recovery device is adapted to recycle and store the swelling hot water in the heater so as to provide an energy-saving effect and to stop water from dripping.

A water heater system having a running water inlet through which running water flows in and a hot water outlet through which hot water heated in a heat exchanger is discharged is disclosed. The water heater system may include a first connection pipe connecting a gap between the running water inlet and an entry of the heat exchanger, a second connection pipe connecting a gap between an outlet of the heat exchanger and the hot water outlet; a bypass pipe connecting a gap between the first connection pipe and the second connection pipe, a bypass valve installed to the bypass pipe so as to control the direction of water flowing through the bypass pipe, and a controller, in a hot water usage mode, controlling the bypass valve so that the water moves from the first connection pipe to the second connection pipe through the bypass pipe, and in an inner circulation mode, controlling the bypass valve so that the water moves from the second connection pipe to the first connection pipe through the bypass pipe.

A combined hot water and air heating and conditioning system including a first heat exchanger, a heat pump, a chilling tower loop, a burner and a second heat exchanger to provide hot water, air heating and air cooling. The system provides hot water, air heating and cooling all in one single unit. The system utilizes a heat pump to remove heat from ambient air and transfer the rejected heat into a hot water system, thereby using waste heat to heat the hot water system. The system utilizes a heat exchanger not only for the purpose of transferring heat from a heating source to a fluid in the heat exchanger but also for the purpose of dissipating heat from the fluid in the heat exchanger to the surroundings of the heat exchanger, thereby allowing a heat pump to act both as an air heating and conditioning device.

A load unit includes a water circuit chamber configured to accommodate at least a part of a water circuit configured to allow water to flow therethrough, a fan, an air inlet formed at a height positioned different from that of the air inlet and configured to suck indoor air therethrough, an air outlet configured to blow indoors the air sucked through the air inlet, and an air passage formed between the air inlet and the air outlet so as to be isolated from the water circuit chamber. A load-side heat exchanger is provided in the air passage.

A dual fluid heat exchange system is presented that provides a stable output temperature for a heated fluid while minimizing the output temperature of a cooled fluid. The heated and cooled fluids are brought into thermal contact with each other within a tank. The output temperature of the warmed fluid is maintained at a stable temperature by a re-circulation loop that connects directly to the mid portion of the tank such that the re-circulated fluid flow primarily warms only a re-circulation section of the tank. The other, lower flow rate, section of the tank may be positioned so that it has a cooler temperature and thus serves to increase the efficiency of the heat exchange by extracting extra heat energy out of the cooled fluid before it leaves the tank. Alternatively, the low flow rate section of the tank may be warmer than the re-circulated section, and thus allow the re-circulated section to be cooler than the output temperature of the warmed fluid.

A thermal storage and exchange heating apparatus includes: a thermal storage tank that stores a heated heat medium; a circulation channel connected to high and low temperature sides of the thermal storage tank, and through which the heat medium circulates; a heat exchanger provided to the circulation channel and configured to exchange heat between the heat medium and a heating object, to heat the heating object; a circulation direction switch configured to switch circulation of the heat medium in the circulation channel between a forward direction from the high-temperature side to the low-temperature side and a reversed backward direction; and a controller configured to cause the heat medium to circulate in the forward direction by switching the circulation direction switch in a heating operation and causing the heat medium to circulate in the backward direction by switching the circulation direction switch after a stop of the heating operation.

A hot water circulation system comprises a water heater having a cold-water inlet and a hot water outlet. A water pump circulates water through the water heater to produce hot water. The hot water is circulated to a thermal bypass valve, which is configured to close when hot water contacts a heat activated seal. A bypass circuit is coupled between the hot water outlet and the cold water inlet of the water heater. The bypass circuit prevents hot water from circulating from the hot water outlet to the cold-water inlet when the thermal bypass valve is open and promotes circulating hot water from the hot water outlet to the cold water inlet when the thermal bypass valve is closed. Upon a temperature sensor sensing hot water entering the cold-water inlet, the water heater turns of the water pump.

An instant hot water delivery system includes a thermal storage bin that receives hot water from a water heater via a hot water supply conduit and stores the hot water therein. The thermal storage bin is disposed adjacent a point of demand to deliver the hot water instantly to the point of demand responsive to a demand. The thermal storage bin is configured to retain a thermal energy of the hot water for a prolonged period using a phase change material. When the hot water stored in the thermal storage bin cools down below a threshold temperature, the cooled down hot water is recirculated to the water heater via a cold water supply conduit using a crossover valve. The recirculation is based on thermosiphon. Fresh hot water from the water heater replaces the cooled down hot water that is displaced from the thermal storage bin.

A recirculation valve for use with a tankless water heater in a system that includes hot and cold water fixtures and a cold water supply. The recirculation valve includes a valve body having an inlet connection, a pair of outlet connections and an internal chamber; a thermostatic element that is disposed in a first portion of the internal chamber of the valve body and includes an actuation body that is responsive to water temperature; wherein the valve body further has a port opening that is disposed between the thermostatic element and a second portion of the internal chamber; wherein the thermostatic element further includes a piston constructed and arranged to operatively extend from said actuation body when the actuation body is heated, and a plunger that is carried by and is moveably responsive to the actuation body; and whereby, when the actuation body is heated, the valve transitions from an open position to a closed position by the piston moving the actuation body and plunger so that the plunger moves to seal against the port opening of the valve body.