A heat storage system includes a compressor that compresses refrigerant; a heat storage tank that stores a heating medium; heat exchange means provided outside the heat storage tank for heating the heating medium using heat of the refrigerant compressed by the compressor; a heat accumulating circuit including a feed path that feeds the heating medium flowing out of the heat storage tank to the heat exchange means, a return path that returns the heating medium heated by the heat exchange means into the heat storage tank, and a pump that circulates the heating medium; and control means capable of executing an initial operation that controls an operating frequency of the compressor at the beginning of a heat accumulating operation in which the heating medium heated by the heat exchange means is accumulated in the heat storage tank. The initial operation includes a first operation that maintains the operating frequency at a first frequency and, after the first operation, a second operation that maintains the operating frequency at a second frequency higher than the first frequency.

A heat storage system includes a compressor that compresses refrigerant; a heat storage tank that stores a heating medium; heat exchange means provided outside the heat storage tank for heating the heating medium using heat of the refrigerant compressed by the compressor; a heat accumulating circuit including a feed path that feeds the heating medium flowing out of the heat storage tank to the heat exchange means, a return path that returns the heating medium heated by the heat exchange means into the heat storage tank, and a pump that circulates the heating medium; and control means capable of executing an initial operation that controls an operating frequency of the compressor at the beginning of a heat accumulating operation in which the heating medium heated by the heat exchange means is accumulated in the heat storage tank. The initial operation includes a first operation that maintains the operating frequency at a first frequency and, after the first operation, a second operation that maintains the operating frequency at a second frequency higher than the first frequency.

A multi-connected heat recovery air conditioning system and a control method thereof. The multi-connected heat recovery air conditioning system includes an indoor unit, an outdoor unit and a hydraulic module, wherein the outdoor unit comprises a compressor, an outdoor heat exchanger, a first four-way valve and a second four-way valve. The multi-connected heat recovery air conditioning system further comprises an indoor unit temperature unit, a water temperature unit, a high-pressure sensor and a low-pressure sensor. The indoor unit temperature unit is arranged in the indoor unit for detecting and obtaining the outlet temperature value of the indoor unit, the water temperature unit is arranged at a heat exchange water tank for detecting and obtaining water temperature, and the high-pressure sensor and the low-pressure sensor are arranged at the output end and the air return end of the compressor respectively.

A retrofit heat pump system for a water heater is disclosed. The heat pump system includes a plurality of evaporators to increase the efficiency of heat exchange for the system. The system can also include a plurality of condenser circuits used to heat the water of an existing water tank. A fan disposed in a housing of the heat pump system can draw air across the plurality of evaporators and exhaust cool air external to the heat pump system. The cool air can be exhausted into duct work associated with an air conditioning system of the home. The disclosure also describes a refrigerant distributor for providing uniform liquid refrigerant to the plurality of evaporators.

A water tank mounting structure and a ventilation treatment apparatus for such structure. The water tank mounting structure comprises a cavity for containing a water tank and a side wall defining the cavity, wherein the side wall comprises an inner side wall spaced apart from an outer side, a first gas hole provided in the inner side wall, and a second gas hole provided in the outer side wall, both holes arranged in a staggered manner perpendicular to the side wall. The arrangement of the double-layer side wall, and the first and second gas holes in the inner and outer side walls, respectively, allows for hot gas in the cavity to be effectively removed. The staggered arrangement of the gas holes allows for water to flow downward along the side wall without invading the cavity when water enters through the second gas hole. A waterproof effect is achieved.

A water tank mounting structure and a ventilation treatment apparatus for such structure. The water tank mounting structure comprises a cavity for containing a water tank and a side wall defining the cavity, wherein the side wall comprises an inner side wall spaced apart from an outer side, a first gas hole provided in the inner side wall, and a second gas hole provided in the outer side wall, both holes arranged in a staggered manner perpendicular to the side wall. The arrangement of the double-layer side wall, and the first and second gas holes in the inner and outer side walls, respectively, allows for hot gas in the cavity to be effectively removed. The staggered arrangement of the gas holes allows for water to flow downward along the side wall without invading the cavity when water enters through the second gas hole. A waterproof effect is achieved.

A hot-water supply system heats up water by power generated by power generation means. The hot water supply system includes a compressor and a water heat-up unit. In the hot-water supply system, the compressor compresses refrigerant and circulates the refrigerant through a refrigerant circuit. The water heat-up unit heats up water by changing, in accordance with the generated power, a rotation rate of an electric motor for driving the compressor.

A hot-water supply system heats up water by power generated by power generation means. The hot water supply system includes a compressor and a water heat-up unit. In the hot-water supply system, the compressor compresses refrigerant and circulates the refrigerant through a refrigerant circuit. The water heat-up unit heats up water by changing, in accordance with the generated power, a rotation rate of an electric motor for driving the compressor.

Photovoltaics and an MPPT DC/DC converter powers a DC bus of a controller. It uses an electric heat pump to heat a mass like water, and also has a resistive heating element to heat the mass. A microcontroller controls a variable frequency (VFD) motor drive to power the electric heat pump when sufficient solar power is available to run the heat pump and uses the resistive element to heat the thermal mass when insufficient solar power exists for the heat pump or when excess solar power is available. A controller has an MPPT input for solar power and a VFD to provide power through an output to a heat pump-based water heater and an output to power a resistive water heating element. A microcontroller determines solar power available and runs the heat pump when possible and the resistive element when insufficient power is available or when excess power is available.

Photovoltaics and an MPPT DC/DC converter powers a DC bus of a controller. It uses an electric heat pump to heat a mass like water, and also has a resistive heating element to heat the mass. A microcontroller controls a variable frequency (VFD) motor drive to power the electric heat pump when sufficient solar power is available to run the heat pump and uses the resistive element to heat the thermal mass when insufficient solar power exists for the heat pump or when excess solar power is available. A controller has an MPPT input for solar power and a VFD to provide power through an output to a heat pump-based water heater and an output to power a resistive water heating element. A microcontroller determines solar power available and runs the heat pump when possible and the resistive element when insufficient power is available or when excess power is available.