A water heater includes a water tank for storing water to be heated and a thermosiphon tube in the water tank. The thermosiphon tube has a first end in a bottom portion of the water tank and a second end in a top portion of the water tank. At least a portion of a condenser tube of a heat pump is surrounded by the thermosiphon tube to define a water flow channel between the thermosiphon tube and the condenser tube. The condenser tube is at an elevated temperature compared to water temperature in the water flow channel due to a refrigerant cycle of the heat pump. A water pump is configured to flow water through the water flow channel to heat the water in the water flow channel and deliver the heated water into the top portion of the water tank through the second end of the thermosiphon tube.

A water mixing system attached to an existing plumbing system supplying ambient temperature water and providing temperature regulated water to a user. The water mixing system includes an insulated water tank, a heat pump connected to the insulated water tank with a heat rejecting radiator inside the insulated water tank and a heat absorbing radiator outside the insulated water tank, a temperature detector in the insulated water tank, and one outlet of the insulated water tank connected to a first inlet of a first dispensing water tank. Having a second inlet to receive the ambient temperature water from the existing plumbing system and at least one dispensing outlet, the first dispensing water tank provides mixed water of a desirable temperature from heated water from the insulated water tank and the ambient temperature water via control of the valves attached to the first inlet and the second inlet.

A water mixing system attached to an existing plumbing system supplying ambient temperature water and providing temperature regulated water to a user. The water mixing system includes an insulated water tank, a heat pump connected to the insulated water tank with a heat rejecting radiator inside the insulated water tank and a heat absorbing radiator outside the insulated water tank, a temperature detector in the insulated water tank, and one outlet of the insulated water tank connected to a first inlet of a first dispensing water tank. Having a second inlet to receive the ambient temperature water from the existing plumbing system and at least one dispensing outlet, the first dispensing water tank provides mixed water of a desirable temperature from heated water from the insulated water tank and the ambient temperature water via control of the valves attached to the first inlet and the second inlet.

Model predictive control methods are disclosed which provide, among other things, efficient strategies for controlling heat-transfer to a fluid.

A water mixing system attached to an existing plumbing system supplying ambient temperature water and providing temperature regulated water to a user. The water mixing system includes an insulated water tank, a heat pump connected to the insulated water tank with a heat rejecting radiator inside the insulated water tank and a heat absorbing radiator outside the insulated water tank, a temperature detector in the insulated water tank, and one outlet of the insulated water tank connected to a first inlet of a first dispensing water tank. Having a second inlet to receive the ambient temperature water from the existing plumbing system and at least one dispensing outlet, the first dispensing water tank provides mixed water of a desirable temperature from heated water from the insulated water tank and the ambient temperature water via control of the valves attached to the first inlet and the second inlet.

Disclosed is a method of mapping an in-building water supply installation having multiple controllable water outlets, the installation including a supply of water; in a water flow path between the supply of water and the controllable water outlets, a flow measurement device and a flow regulator; a processor being operatively connected to the flow measurement device and the at least one flow regulator. The method comprises opening a first of the water outlets and processing signals from the flow measurement device with the processor at least until a first flow characteristic is determined; closing the first of the water outlets; repeating the opening, processing and closing operations for each of the other water outlets to determine for each controllable water outlet a respective flow characteristic. Subsequently the processor is configured to; identify the opening of a particular one of the plurality of controllable water outlets based on the similarity of a detected flow characteristic to a respective flow characteristic; and control said at least one flow regulator, based on the identification, to control a supply of water to the identified controllable water outlet.

A storage water heater includes at least one heating device, at least one storage tank wherein water is stored and heated, at least one control and management unit capable of checking at least the heating device, at least one inlet duct through which water may be introduced into the tank, at least one outlet duct through which water may be sent/withdrawn from the tank, wherein there are at least two heating devices, of which at least one main heating device and at least one auxiliary heating device are provided, and wherein the water heater includes a circulator dedicated, via at least one hydraulic connection duct, to the recirculation of the storage water stored in the tank, the circulator being capable of recirculating the water of the storage between the lower part and the top part of the tank, by passing through the auxiliary heating device.

A storage water heater includes at least one heating device, at least one storage tank wherein water is stored and heated, at least one control and management unit capable of controlling the at least one heating device, at least one inlet duct through which water may be introduced into the tank, at least one outlet duct through which water may be sent/withdrawn from the tank, at least two heating devices, of which at least one main heating device and at least one second auxiliary heating device adapted to act as a pre-heater, wherein the water heater includes a by-pass duct capable of deviating, entirely or partially, the water flow entering the tank so as to guide and convey it in a zone of the tank placed at a height higher than the outlet section of the inlet duct.

A heat pump water heater has a tank, a heat source, and a heat pump system. The heat pump system has a refrigerant path, at least a portion of which is in thermal communication with the water tank volume so that heat transfers from refrigerant to the water tank volume. A fan causes air to flow through a housing, and another portion of the refrigerant path includes an evaporator in the housing. The fan is within the housing and may further be within a second housing. The first housing may comprise a baffle to direct air flow. The fan may be a variable speed fan in communication with a controller, so that the controller controls the fan speed depending on a temperature of the refrigerant.

A hot water system and method are provided. The system includes a tank configured to receive hot water, a heat recovery system for heating water, and a controller configured to use the heat recovery system to maintain the hot water in the tank at a temperature within a predetermined range of temperatures. The method involves receiving a flow of water and heating the water using the hot water system.