Control principle of refrigerators

A non-expert’s makeshift explanation, for reference only. First, understand the physical and chemical properties of the refrigerant. Then, search online for animated illustrations explaining how refrigerators work; there might be some available. Then, the general operating process of a refrigeration unit is as follows: Utilizing the physical properties of the refrigerant, it first exchanges heat in the evaporator, absorbing heat and releasing coldness, thereby transitioning from a liquid to a gaseous state. It then enters the compressor, where its pressure is increased. The condenser cools and liquefies the compressed gas. Next, it passes through a throttle valve (along with a desiccant and filter), and finally returns to the evaporator, thus completing the cycle. Set an interlock temperature for the evaporator temperature to prevent the cooled medium from freezing the evaporator. For reference.

Propylene is similar to Freon; it is a gas that can be compressed and expanded. The principle is that the compressor increases the pressure of the refrigerant, causing it to heat up; in this process, the refrigerant needs to be cooled using air cooling or water cooling. After being cooled, it expands in the evaporator and absorbs heat. The heat absorbed here by the single-stage refrigerant can then be used to cool water or alcohol. In a multi-stage system, the first stage may be used to cool the second stage, while the second or third stage is used to cool the alcohol. The control is achieved through a circuit board that regulates the opening and closing of various valves and motors; thermometers, pressure gauges, and flow meters are used for feedback

When using propylene to cool other media, the compressor’s loading and unloading can generally be controlled based on the suction pressure or the refrigerant temperature.