An apparatus for heating water has a tank for storing water and an air conditioning system that defines a refrigerant flow path through which refrigerant flows. The refrigerant flow path passes through a heat exchanger so that refrigerant heat is contributed to the tank. The heat exchanger houses a phase change material. A controller controls operation of the water heating apparatus.

A method of defrosting a heat pump device including a water tank, a heat exchanger, an electrical heating element, an evaporator, a fan for the evaporator, and a control unit. In a first operating mode, the heat pump device is controlled to heat water inside the water tank. In a second operating mode, the electrical heating element is manually activated to additionally heat the water inside the water tank. In a third operating mode, the electrical heating element is automatically activating to heat the water in the storage tank if: the power supplied by the heat pump device to heat the water inside the water tank is not sufficient; if a time limit after activation of a deicing operation has lapsed; and/or if the number of times the deicing operation has been activated during a predetermined time interval exceeds a threshold value.

A method of defrosting a heat pump device including a water tank, a heat exchanger, an electrical heating element, an evaporator, a fan for the evaporator, and a control unit. In a first operating mode, the heat pump device is controlled to heat water inside the water tank. In a second operating mode, the electrical heating element is manually activated to additionally heat the water inside the water tank. In a third operating mode, the electrical heating element is automatically activating to heat the water in the storage tank if: the power supplied by the heat pump device to heat the water inside the water tank is not sufficient; if a time limit after activation of a deicing operation has lapsed; and/or if the number of times the deicing operation has been activated during a predetermined time interval exceeds a threshold value.

A system for heating a first fluid flow from a first temperature to a second temperature, the system including a hot water supply line for receiving the first fluid flow at a first end and exhausting the first fluid flow at a second end; and a heating system including a heat engine, a thermal battery and a heat exchanger, wherein the thermal battery is configured to be replenished at a point of heat transfer by the heat engine and the hot water supply line is configured to receive heat from the thermal battery via the heat exchanger to elevate the temperature of the first fluid flow from the first temperature to the second temperature.

A hot water supply apparatus includes: a first channel configured to send water in a medium-temperature layer (M) to a heating section; and a second channel configured to return water heated by the heating section to a tank. The second channel has an outflow port at a lower position than an inflow port of the first channel.

The disclosed technology includes an on-demand water heater which uses an electric heat source to heat the water. The on-demand water heater can have a low fluid capacity heating chamber which has an inlet and an outlet, an electric heat source for heating the water, and a controller to control the electric heat source and maintain the temperature of the water at a predetermined temperature setting. The on-demand water heater can be powered by a direct current power source. The on-demand water heater can also utilize a solar thermal system to provide additional heat to the water.

The disclosed technology includes an on-demand water heater which uses an electric heat source to heat the water. The on-demand water heater can have a low fluid capacity heating chamber which has an inlet and an outlet, an electric heat source for heating the water, and a controller to control the electric heat source and maintain the temperature of the water at a predetermined temperature setting. The on-demand water heater can be powered by a direct current power source. The on-demand water heater can also utilize a solar thermal system to provide additional heat to the water.

A combination water heating, air conditioning refrigerant system is described. The combined system includes a plurality of independently adjustable electronic expansion valves. The expansion valves can independently modulate the delivery of high-temperature, high-pressure refrigerant to either a water heat exchanger or an outside condenser. A controller can receive input signals, including temperature signals from one or more temperature sensors that indicate the temperature at various locations of the system. The temperature signals include one or more of water temperature signals, ambient air temperature signals, or refrigerant super heat temperatures signals. In response to the input signals, the controller can output control signals to one or more of the plurality of electronic expansion valves.

A system for providing air conditioning to a living space and heating potable water. The system comprising a heat pump circuit comprising a compressor for circulating a refrigerant around the heat pump circuit, a first condenser, a second condenser and an evaporator. The evaporator being adapted to receive a first flow of air from an air inlet to transfer heat from the first flow of air to the refrigerant. The first condenser being adapted to receive a flow of water to transfer heat from the refrigerant to the water. The second condenser being adapted to receive a second flow of air to transfer heat from the refrigerant to the second flow of air. The first flow being provided from the evaporator to a living space by an air outlet.

A rotor is a rotor for a pump. The rotor includes a rotor core having a magnet insertion hole and having an annular shape about an axis, a permanent magnet inserted in the magnet insertion hole, and a rotor cover surrounding the rotor core from outside in a radial direction about the axis. The rotor core has a first core portion disposed on an inner side of the magnet insertion hole in the radial direction, a second core portion disposed on an outer side of the magnet insertion hole in the radial direction, and a hole separating the first core portion and the second core portion from each other. The rotor cover has a positioning portion that positions the first core portion and the second core portion in a circumferential direction about the axis.