A heat pump and a control method thereof, the control method of the heat pump which heats a heated space through heat exchange between outdoor air and a refrigerant and heat exchange between the refrigerant and circulation water, includes calculating the maximum allowable frequency of a compressor based on the temperature of the outdoor air and the heating load of the heated space, calculating the mean operating frequency of the compressor while the compressor is operated at the calculated maximum allowable frequency, recalculating the maximum allowable frequency based on a result of comparison between the mean operating frequency and the maximum allowable frequency, and operating the compressor at the recalculated maximum allowable frequency, thereby improving coefficient of performance (COP) of the heat pump.

Controlling heating and cooling in a conditioned space utilizes a fluid circulating in a thermally conductive structure in fluid connection with a hydronic-to-air heat exchanger and a ground heat exchanger. Air is moved past the hydronic-to-air heat exchanger, the air having fresh air supply and stale air exhaust. Sensors located throughout the conditioned space send data to a controller. User input to the controller sets the desired set point temperature and humidity. Based upon the set point temperature and humidity and sensor data, the controller sends signals to various devices to manipulate the flow of the fluid and the air in order to achieve the desired set point temperature and humidity in the conditioned space. The temperature of the fluid is kept less than the dew point at the hydronic-to-air heat exchanger and the temperature of the fluid is kept greater than the dew point at the thermally conductive structure.

When a heating operation mode using a heating unit is specified and when a hot water supply request using the hot water in a hot water storage tank does not occur, an air conditioning apparatus transmits a first selection signal for selecting the heating unit to a three-way valve. When the heating operation mode is specified and when the hot water supply request occurs, the air conditioning apparatus transmits, to the three-way valve, a second selection signal for changing a destination of circulation of secondary refrigerant from the heating unit to a coil heat exchanger, and transmits an operation start signal to a refrigerant indoor unit.

Heat pump system (100) comprising a heat medium circuit (210,220,230,240,250,310,320,410,420,430,440,450,460) in turn comprising at least three heat exchanging means (314,315,315,422,433,452) between the heat medium and a respective heat source or sink selected from outdoor air, a water body, the ground, indoorair, pool water or tap water, a valve means (311,312,313,421,431,451) arranged to selectively direct the heat medium to at least two of said heat exchanging means, and a control means (500). The invention is characterized in that the heat pump system comprises temperature sensors (314a,314b;315a,315b;316a,316b;423,424,425;432,434,435) both upstream and downstream of at least one of said heat exchanging means, in that the system determines, based upon temperature measurement values comprising at least onevalue read from said sensors, to what heat exchanging means the heat medium is to be directed, and in that when heat medium is not directed to a certain heat exchanging means a measured temperature value is read upstream and downstream of the certain heatexchanging means, and in that an alert is set off in case the values differ by more than a predetermined value. The invention also relates to a method.

An air-conditioning and hot water supplying composite system includes a heat source unit and a heat source-side heat exchanger, an indoor heat source unit, a hot water supply unit connected to the heat source unit and including a hot water supply-side heat exchanger and a hot water supply-side expansion device, and a controller that controls the heat source unit. The controller includes a mode switching unit that switches a control mode of the air-conditioning and hot water supplying composite system between a hot water supply control mode, a hot water supply preheating mode, and a condensing temperature control unit. The condensing temperature control unit determines the target condensing temperature according to a temperature of a heat medium subjected to heat exchange by the hot water supply unit, in the hot water supply control mode.

A water heater appliance includes an electronic mixing valve configured for adjusting a ratio of cold water from a cold water inlet conduit to hot water from a hot water outlet conduit at a mixed water outlet of the electronic mixing valve. A flow meter is mounted to the mixed water outlet conduit or the cold water inlet conduit. A controller is configured to calculate a flow rate of hot water through the hot water outlet conduit based on a temperature measurement from each of a mixed water temperature sensor, a cold water temperature sensor and a hot water temperature sensor and a flow rate measurement from the flow meter.

A water heater appliance includes an electronic mixing valve configured for adjusting a ratio of cold water from a cold water inlet conduit to hot water from a hot water outlet conduit at a mixed water outlet of the electronic mixing valve. A cold water bypass conduit extends between the cold water inlet conduit and the mixed water outlet conduit. A cold water bypass valve is on the cold water bypass conduit. A controller is configured to close the cold water bypass valve when a temperature measurement from a mixed water temperature sensor is less than a threshold temperature.

A water heater appliance includes an electronic mixing valve configured for adjusting a ratio of cold water from a cold water inlet conduit to hot water from a hot water outlet conduit at a mixed water outlet of the electronic mixing valve. A cold water bypass conduit extends between the cold water inlet conduit and the mixed water outlet conduit. A cold water bypass valve is on the cold water bypass conduit. A controller is configured to close the cold water bypass valve when a temperature measurement from a mixed water temperature sensor is less than a threshold temperature.

A system for conditioning air circulated from an interior of a building includes a refrigerant path, an air-cooled condenser in the refrigerant path, a water-cooled condenser in the refrigerant path that transfers heat from refrigerant in the refrigerant path to the building water, an evaporator in the refrigerant path, and a control system. The control system moves the system between operation of the air-cooled condenser and the water-cooled condenser based upon predetermined system conditions.

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: a) the power supplied by the heat pump device to heat the water inside the water tank is not sufficient; b) if a time limit after activation of a deicing operation has lapsed; and/or c) if the number of times the deicing operation has been activated during a predetermined time interval exceeds a threshold value.