Working principle of air-cooled cooling and heating machine

As an important temperature regulating device, air-cooled chillers and heaters play a key role in many fields. Whether it is to ensure the suitable ambient temperature for stable operation of equipment in industrial production, to create a comfortable space atmosphere for people in commercial places, or in some scientific research experimental environments with high requirements for temperature accuracy, air-cooled chillers and heaters have become a powerful assistant in maintaining temperature stability with their efficient and reliable performance. To deeply understand the superior performance of air-cooled chillers and heaters, we must start with their core working principles.

The working principle of air-cooled chillers is based on the reverse Carnot cycle, and the temperature is regulated mainly through the coordinated operation of the refrigeration system and the heating system. The refrigeration system is the key part of the air-cooled chiller to achieve the cooling function. It is mainly composed of four core components: compressor, condenser, expansion valve and evaporator. Each component cooperates with each other to complete the heat transfer.

The compressor plays the role of "power heart" in the entire refrigeration cycle. It compresses low-temperature and low-pressure gaseous refrigerant into high-temperature and high-pressure gaseous refrigerant through mechanical work. In this process, the compressor works on the refrigerant, increases the internal energy of the refrigerant, and significantly increases its temperature and pressure. This is like injecting "energy" into the refrigerant, enabling it to have the ability to exchange heat in subsequent links.

After being compressed by the compressor, the high-temperature and high-pressure gaseous refrigerant then enters the condenser. The condenser is an important heat exchange component, and its function is to dissipate the heat carried by the refrigerant into the surrounding environment. In an air-cooled refrigerator, the condenser is air-cooled, that is, a fan is used to force the outside air to blow through the heat dissipation fins of the condenser. When the high-temperature and high-pressure gaseous refrigerant flows in the condenser, it exchanges heat with the relatively low-temperature outside air. The heat is transferred from the refrigerant to the air, and the refrigerant gradually cools and condenses into a high-pressure liquid in the process. This process is similar to our daily life, when hot water vapor encounters a cold surface and condenses into water droplets, except that here the refrigerant releases heat to the air and undergoes a phase change.

The high-pressure liquid refrigerant coming out of the condenser then enters the expansion valve. The expansion valve is a throttling device in the refrigeration system. Its function is to throttle and reduce the pressure of the high-pressure liquid refrigerant. When the high-pressure liquid refrigerant passes through the expansion valve, due to the throttling effect of the expansion valve, the pressure of the refrigerant drops instantly, and its temperature also drops, turning into a low-temperature and low-pressure liquid refrigerant. This process is like letting a high-speed flowing water flow through a narrow hole, and the pressure and speed of the water flow will change.

After the expansion valve throttles and reduces the pressure, the low-temperature and low-pressure liquid refrigerant enters the evaporator. The evaporator is also a heat exchange component, and the heat exchange process that occurs here is the opposite of that of the condenser. The low-temperature and low-pressure liquid refrigerant in the evaporator absorbs heat from the surrounding environment and gradually evaporates and vaporizes into a low-temperature and low-pressure gaseous refrigerant. Taking air conditioning as an example, when the indoor air is blown over the surface of the evaporator by the fan, the heat in the air is absorbed by the refrigerant in the evaporator, thereby reducing the indoor air temperature and achieving a cooling effect. The low-temperature and low-pressure gaseous refrigerant coming out of the evaporator will enter the compressor again to start a new round of refrigeration cycle.

In heating mode, the air-cooled chiller mainly changes the flow direction of the refrigerant through the four-way reversing valve, thereby realizing the reverse operation of the refrigeration cycle and achieving the purpose of heating. When the chiller switches to heating mode, the four-way reversing valve operates, turning the component that originally served as the condenser into an evaporator, and the original evaporator into a condenser. At this time, the high-temperature and high-pressure gaseous refrigerant discharged by the compressor first enters the evaporator on the indoor side (at this time as a condenser), where the refrigerant releases heat to the indoor air, raising the indoor air temperature and realizing the heating function. After heat dissipation, the refrigerant becomes a high-pressure liquid, then throttles and reduces the pressure through the expansion valve, and then enters the condenser on the outdoor side (at this time as an evaporator), absorbs heat from the outside air, vaporizes into a low-temperature and low-pressure gaseous refrigerant, and returns to the compressor to complete the heating cycle.

Air-cooled chillers and heaters achieve efficient and reliable temperature regulation through ingenious cooling and heating cycle design, using the coordinated work of core components such as compressors, condensers, expansion valves and evaporators, as well as the control of the refrigerant flow direction by the four-way reversing valve in the heating mode. Whether it brings coolness to people in the hot summer or provides warmth in the cold winter, air-cooled chillers and heaters have become important equipment to ensure the comfort of people's living and working environments due to their unique working principles. At the same time, they also provide stable and accurate temperature control solutions for many industrial and scientific research fields that have strict temperature requirements.