A refrigerator and a method of controlling an operation thereof are proposed. In the refrigerator and method thereof, heat control of heaters for preventing a damper from freezing is performed according to at least any one condition set in consideration of a room temperature and refrigerator internal humidity. Accordingly, consumption of power due to unnecessary heat generation of the heaters may be reduced, thereby improving the power consumption.

According to one embodiment, a motor drive unit includes a motor including a plurality of phase windings in a mutually unconnected state, a first inverter which controls application of electric power to one ends of the phase windings, a second inverter which controls application of electric power to the other ends of the phase windings, relays each of which includes a make break contact connected between the other ends of the phase windings, and a controller which switches, according to a value of a current flowing through the motor, between an open-windings mode and a star-connection mode.

A refrigerator of the present invention comprises: an inner case forming a storage compartment; a cold air duct guiding the flow of air within the storage compartment and forming a heat exchange space with the inner case; an evaporator disposed in the heat exchange space between the inner case and the cold air duct; a bypass passage disposed in the cold air duct so as to allow the flow of air to bypass the evaporator; a sensor disposed in the bypass flow channel and comprising a sensor housing, a sensor PCB received in the sensor housing, a heating element installed on the sensor PCB so as to generate heat when an electric current is applied thereto, a temperature element for sensing the temperature of the heating element, and a molding material with which the sensor housing is filled; a drfrosting means for removing frost formed on the surface of the evaporator; and a control unit for controlling the defrosting means on the basis of the value output from the sensor.

A refrigerator and method utilize a pair of tandem evaporators to provide cooling for both a compartment and an ice making system of a refrigerator. An upstream evaporator in the pair of tandem evaporators provides cooling for a compartment such as a freezer, fresh food, flexible cooling, or quick cooling compartment, while a downstream evaporator is in fluid communication with the upstream evaporator to receive a portion of the air cooled by the upstream evaporator and further cool the received portion for use in cooling one or more components of the ice making system.

A refrigerator includes a cabinet configured to form a first storage chamber and a second storage chamber, a first evaporator configured to cool the first storage chamber, a first fan configured to circulate air in the first storage chamber to the first evaporator and the first storage chamber, a second evaporator configured to cool the second storage chamber, a compressor configured to be connected to the first evaporator and the second evaporator, a second fan configured to circulate air in the second storage chamber to the second evaporator and the second storage chamber; a refrigerant valve configured to guide refrigerant to the first evaporator or the second evaporator, and a controller configured to perform a plurality of modes sequentially to defrost the second evaporator.

To provide a defrost system capable of preferable defrosting and prevention of generation of icicles on a casing without installing a brine circuit. A defrost system includes a thermosiphon defrost circuit that is provided by being branched from a circulation line, in which, at the time of defrosting, a CO.sub.2 refrigerant staying inside a fin-tube heat exchanger repeats a two-phase change of a gaseous form and reliquefaction, and which forms a CO.sub.2 circulation path together with the fin-tube heat exchanger; electromagnetic opening/closing valves that are closed at the time of defrosting and set the CO.sub.2 circulation path to a closed circuit; and a first electric heater arranged above the thermosiphon defrost circuit so as to be adjacent to the thermosiphon defrost circuit, and naturally circulates the CO.sub.2 refrigerant in the closed circuit at the time of defrosting.

A three-pipe multi-split hot water system, including: an outdoor unit, the outdoor unit including a compressor, an oil separator, a first switching apparatus, a second switching apparatus, a fin heat exchanger, a double-pipe heat exchanger, a compressor heat dissipation module, a plate heat exchanger, a first electronic expansion valve, a second electronic expansion valve, a third electronic expansion valve, and a gas-liquid separator; at least two indoor units, any one of the indoor units including an indoor unit heat exchanger, a fourth electronic expansion valve, and an indoor unit fan; and a hydraulic module, the hydraulic module including a refrigerant-water heat exchanger, a water pump, a water temperature detection sensor, a water flow switch, a solenoid valve, and a fifth electronic expansion valve, where the outdoor unit is connected to any one of the indoor units and to the hydraulic module by a gas pipe and a liquid pipe.

A heat pump includes a compressor, a metering device, a first heat exchanger, a second heat exchanger, a first fan, a second fan, and a refrigerant circuit between the first heat exchanger and the second heat exchanger. A thermal storage device coupled to the refrigerant circuit is configured to store thermal energy when the refrigerant fluid is above a threshold temperature and discharge thermal energy when the refrigerant fluid is below the threshold temperature. The heat pump is operated in a heating mode in which heat is transferred from the refrigerant fluid at the first heat exchanger and the temperature of the refrigerant fluid at the thermal storage device is above the threshold temperature, and a defrost mode in which heat is transferred to the refrigerant fluid at the first heat exchanger and the temperature of the refrigerant fluid at the thermal storage device is below the threshold temperature.

A refrigerating and air-conditioning apparatus performs, even during a heating operation under air conditions leading to formation of frost, a defrosting operation while simultaneously continuing the heating operation and improves comfort through heating by securing an appropriate amount of ventilation. A plurality of refrigeration cycles independently performs a heating operation and a defrosting operation. By controlling a ventilation damper of an indoor unit that is to perform a defrosting operation to increase the amount of ventilation, a prior ventilation operation for securing the time-averaged required amount of ventilation including the period in which the defrosting operation is being performed is performed before the defrosting operation, and after the prior ventilation is terminated, the defrosting operation is started.

Disclosed therein are a heat pump system for a vehicle and a method of controlling the heat pump system, which determines that frosting begins on an exterior heat exchanger and carries out a defrosting control if a difference value between outdoor temperature and refrigerant temperature of an outlet side of the exterior heat exchanger is above a frosting decision temperature in a heat pump mode, thereby increasing frost-prevention and defrosting effects and enhancing heating performance and stability of the system because the system recognizes the beginning of frosting on the exterior heat exchanger at a proper time so as to carry out the defrosting control.