Abstract: An air purification device includes a housing, an air quality sensor, an LED light group, and a controller. The air quality sensor is mounted within the housing and detects air quality parameters in real time. The LED light group is mounted within the housing and includes at least one LED light. The controller is mounted within the housing and controls the at least one LED light of the LED light group to emit light of a corresponding color according to the air quality parameters. The emitted light corresponds in color to indicate an air quality.

Abstract: A noise reduction device for reducing noise in refrigeration equipment includes at least one transition tube having a diameter gradually increasing from a capillary of the refrigeration equipment to an evaporator of the refrigeration equipment. The refrigerant liquid is circulated through the noise reduction device.

Abstract: A refrigerator includes a refrigeration system and a heating chamber powered by a part of the refrigeration process. The refrigeration system is a closed and recycling system which comprises a compressor, a first condenser, a three-way magnetic valve, a second condenser, at least one capillary pipeline, and an evaporator. The heating chamber is located around the first condenser, and the first condenser emits to the heating chamber heat which is emitted by the refrigeration system.