A defrost or thaw measuring device has a dumbbell or hourglass-shaped rotatable compartment with a cavity, the cavity being partly filled with at least two phase change materials having different melting points. The measuring device may determine the time period of thawing at two or more temperature intervals in the refrigeration space.

A thawing method for a thawing device includes: generating a radio frequency signal; acquiring the radio frequency signal; an upper electrode plate and a lower electrode plate of the thawing chamber generating, according to the radio frequency signal, radio frequency waves having a corresponding frequency in a thawing chamber and thawing an object to be processed, obtaining voltages and currents of the incident wave signal and reflected wave signal, and determining a thawing progress of the object to be processed.

A thawing method for a thawing device includes: generating a radio frequency signal; acquiring the radio frequency signal; an upper electrode plate and a lower electrode plate of the thawing chamber generating, according to the radio frequency signal, radio frequency waves having a corresponding frequency in a thawing chamber and thawing an object to be processed, obtaining voltages and currents of the incident wave signal and reflected wave signal, and determining a thawing progress of the object to be processed.

A capacitance sensing system for sensing frost and ice accumulation. The capacitance sensing system comprises a first capacitor formed by a portion of a metal heat exchanger and a sensor electrode electrically isolated from the metal heat exchanger, a tank oscillator comprising a second capacitor and an inductor connected in parallel with each other and coupled in parallel with the first capacitor, and a circuit coupled to the tank oscillator. The circuit coupled to the tank oscillator is configured to determine a resonant frequency of the tank oscillator, determine a capacitance value based on the resonant frequency of the tank oscillator, determine that the capacitance value is greater than a predefined threshold, and transmit a heater activation command in response to determining the capacitance value is greater than the predefined threshold.

A transport refrigeration unit (TRU) is provided. The TRU includes a housing defining a flow path from an intake to an outlet, a blower to drive air along the flow path from the intake to the outlet, coils disposed in the flow path between the intake and the outlet and over which the air driven by the blower flows, a defrost element to execute a defrost action with respect to the coils, sensing elements at the intake and the outlet to sense pressures of the air at the intake and the outlet and a controller. The controller is configured to control at least one of the blower and the defrost element in accordance with readings of the sensing elements.

A refrigerator includes a storage compartment; a first flow path separated from the storage compartment; an evaporator provided on the first flow path to cool air; a compressor configured to discharge a refrigerant to the evaporator; a blower fan configured to discharge air of the first flow path to the storage compartment; a defrost heater provided on the first flow path to heat the evaporator; a second flow path separated from the first flow path; a defrost fan configured to suction air of the first flow path into the second flow path; and a controller configured to alternately perform a cooling operation and a defrosting operation, configured to operate the compressor and the blower fan during the cooling operation, configured to operate the defrost heater and the defrost fan during the defrosting operation, and configured to vary a rotational speed of the defrost fan.

A method of operating an air conditioner unit to implement effective defrost cycles includes obtaining a coil temperature of an outdoor heat exchanger, a dew point of a flow of air through the outdoor heat exchanger, and a flow rate of the flow of air. A frost rate of frost buildup on the outdoor heat exchanger is estimated based on the coil temperature, the dew point, and the flow rate, and a frost quantity or weight is determined by integrating the frost rate. A defrost cycle is initiated if the frost quantity exceeds a predetermined frost threshold, e.g., in pounds of water.

A heat pump system including a charge compensator having a liquid line port for an inflow of a refrigerant into the charge compensator and for an outflow of the refrigerant from the charge compensator. The heat pump system further includes an isolation valve configured to control flows of the refrigerant to and from the charge compensator through a liquid line piping of the heat pump system based on whether the heat pump system is operating in a cooling mode, a defrost mode, or a heating mode, where the liquid line port is fluidly coupled to the liquid line piping of the heat pump system.

Example systems have a defrost system that can receive a first RF signal at a first frequency to defrost a load. An air treatment device can receive a second RF signal at a second frequency and perform an air treatment process. An RF signal source has a power output, and a switching arrangement selectively electrically connects the defrost system and the first air treatment device to the power output of the RF signal source. A controller can electrically connect one of the defrost system and the first air treatment device to the power output of the RF signal source. When the defrost system is electrically connected, the RF signal source outputs the first RF signal at the first frequency, and when the first air treatment device is electrically connected, the RF signal source outputs the second RF signal at the second frequency.

A refrigerator including a compressor, a condenser, a freezing chamber evaporator, a freezing chamber fan, a defrosting heater, a wine chamber evaporator, a wine chamber fan, a path switching device configured to guide the refrigerant condensed in the condenser to the freezing chamber evaporator in a freezing chamber mode and to guide the refrigerant condensed in the condenser to the wine chamber evaporator in a wine chamber mode, and a controller configured to turn on the defrosting heater to perform a freezing chamber defrosting mode for defrosting the freezing chamber evaporator, to control the path switching device to the wine chamber mode while the temperature of the wine chamber is dissatisfied when the temperature of the wine chamber is dissatisfied in the freezing chamber defrosting mode, and to drive the wine chamber fan.