Freezing: The operation process of using the low temperature source generated by refrigeration to cool the product from normal temperature and then freeze.
Refrigeration: The process of using the physical state of the refrigerant to change the cooling effect to obtain a low-temperature source.
Types of refrigeration equipment: cold source production (refrigeration), material freezing and cooling.
Refrigeration methods: piston, screw, centrifugal refrigeration compressor units, absorption refrigeration units, steam jet refrigeration units and liquid nitrogen.
Freezing method: air-cooled, immersed, and cooling device through metal pipe, wall and material contact heat transfer and cooling device.
The principle of refrigeration cycle
Main devices: refrigeration compressor, condenser, expansion valve, evaporator.
Principle of the refrigeration cycle: The refrigerant absorbs heat in the low-temperature and low-pressure liquid state and then evaporates into low-temperature and low-pressure vapor. The evaporated refrigerant becomes a high-temperature and high-pressure gas under the action of the compressor. The high-temperature and high-pressure condensation becomes a high-pressure liquid and a high-pressure liquid. It turns into a low-pressure and low-temperature liquid through the expansion valve, and then absorbs heat and evaporates again to form the refrigeration cycle of the refrigerator.
Basic concepts and principles
Direct refrigeration: In the refrigeration cycle, if the refrigerant absorbs heat, the evaporator directly exchanges heat with the object being cooled or the surrounding environment of the object being cooled. The editor tells everyone that the ultra-low temperature freezer is generally used in a single freezing equipment that requires cold work, such as ice cream freezers, small refrigerators and household refrigerators.
Refrigerant: The working substance that continuously circulates in the refrigeration device to achieve refrigeration. The vapor compression refrigeration device realizes the transfer of heat through the change of the refrigerant state. Refrigerant is an indispensable substance for artificial refrigeration.
Indirect refrigeration: Use cheap materials as media carriers to realize heat exchange between the refrigeration device and the cold-consuming place or machine.
Carrying refrigerant: The cold energy produced in the refrigerant carrier evaporator of the refrigeration device is transferred to the heat absorbed by the object to be cooled, and then transferred to the refrigerant. The editor of the ultra-low temperature freezer tells everyone that this is self-cooling recycle.
Principle of indirect evaporative refrigeration
Principle of indirect refrigeration: After the refrigerant absorbs the cold energy from the refrigerant in the evaporator, it enters the cold storage through the brine pump, exchanges heat with the object to be cooled or the medium in the workplace to absorb heat, and returns to the evaporator to absorb the heat. The heat is then transferred to the refrigerant, and it can be reused in a cooling cycle.