Provided is a refrigeration apparatus capable of reducing the leakage of a refrigerant even when a refrigerant leak occurs in a defrosting operation of a usage-side heat exchanger. When a refrigerant leak situation around a usage-side heat exchanger satisfies a predetermined leak condition in performing a defrosting operation with a connection state of a four-way switching valve brought into a defrosting connection state in which a heat source-side heat exchanger functions as an evaporator for a refrigerant and a usage-side heat exchanger functions as a radiator for the refrigerant, a controller performs density lowering control to lower a refrigerant density in the usage-side heat exchanger while maintaining the four-way switching valve at the defrosting connection state.

A refrigerator and a control method, device and system thereof are provided. The method comprises detecting and confirming that the cumulative running time of a compressor is no less than a running time threshold, and an ice maker is currently in a working state, and controlling the ice maker to perform an defrosting operation after a current ice making period is ended, the running time threshold being a time difference between the defrosting period of the refrigerator and the ice making period of the ice maker. The method allows avoiding defrosting in the ice making period, and therefore, the influence of defrosting on ice making of the ice maker can be reduced, the ice making efficiency and the ice making capacity if the ice maker can be effectively promoted, the ice making period is shortened, energy consumption is reduced, and produce reliability is improved.

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 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 defogging control system includes a plurality of first heating wires, a plurality of second heating wires, an electrical sensor and driver, a timer, an environment sensing module, and a control module. The electrical sensor and driver is utilized to generate a start signal or a stop signal, corresponding to a controller of a refrigeration storage apparatus. The timer is utilized to count a real-time operation time and record a previous operation time. The environment sensing module is utilized to sense a temperature and a humidity. The control module is utilized to control the first heating wires and the second heating wires by the real-time operation time, the previous operation time, the temperature, and the humidity. Further, a defogging control method is also provided.

The present invention provides a control method of a refrigerator, comprising: a first defrosting step of defrosting an evaporator and terminating the defrosting when the evaporator reaches a first temperature; a step of detecting pressure difference by means of a differential pressure sensor for measuring pressure difference between a first thru-hole, disposed between the evaporator and an inlet through which air flows in from a storage compartment, and a second thru-hole disposed between the evaporator and an outlet through which the air is discharged into the storage compartment; and a second defrosting step of additionally defrosting the evaporator if the measured pressure difference is greater than a configured pressure.

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 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 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 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.