How air conditioning works

Air conditioners are a very common household appliance, especially in the south. It is very cold in winter and there is no heating. Air conditioners can drive away the cold in winter. It is also very hot in summer, so we cannot do without air conditioners. Air conditioners have made great contributions to us. But do you really understand this appliance? Do you know how it works? Let's learn more about it.

Everyone should have an air conditioner in their home. The most commonly used functions of an air conditioner are heating and cooling. These functions of an air conditioner are amazing, but not many people know much about them, let alone the working principles of air conditioners. If everyone understands the working principles of air conditioners, it can help us make better choices and repairs.

Household air conditioners generally use mechanical compression refrigeration devices, which have four basic components: compressor, evaporator, condenser and throttling device. The four are interconnected and filled with refrigerant (also known as refrigerant). The compressor is like a surging heart, making the refrigerant flow continuously in the air conditioner like blood, thereby regulating the room temperature.

Refrigerants usually exist in several forms: liquid, gas, and gas-liquid mixture. The transformation between these states will cause heat absorption and dissipation, thus causing changes in the external ambient temperature. The process of transformation from gas to liquid is called liquefaction, which releases heat; conversely, the process of transformation from liquid to gas is called vaporization (including evaporation and boiling) and absorbs heat from the outside.

First, low-pressure gaseous refrigerant is sucked into the compressor and compressed into a high-temperature and high-pressure gas; then, the gaseous refrigerant flows to the outdoor condenser, and in the process of heat dissipation to the outdoors, it gradually condenses into a high-pressure liquid; then, it is reduced in pressure (and temperature at the same time) through the throttling device and becomes a low-temperature and low-pressure gas-liquid mixture again. At this time, the gas-liquid mixture of refrigerant can exert the "power" of air conditioning refrigeration: it enters the indoor evaporator and continuously vaporizes by absorbing heat from the indoor air. In this way, the temperature of the room is lowered, and it turns into low-pressure gas again and re-enters the compressor. This cycle repeats itself and the air conditioner can operate continuously.

Refrigerant is amazing! How does it condense at high temperature to dissipate heat to the outside world and evaporate at low temperature to absorb heat from the outside world? This is related to the properties of the refrigerant itself. As we all know, it is difficult to cook eggs on the top of a mountain, but when cooking in a pressure cooker, fish, meat and other foods can be cooked quickly. This is because as the pressure increases, the saturation temperature of water (usually called the boiling point) also increases. Therefore, when the atmospheric pressure is lower than the standard atmospheric pressure, the boiling point of water is lower than 100oC, otherwise it is higher than 100oC. Similarly, the saturation temperature of high-temperature and high-pressure gaseous refrigerant is higher than the outdoor temperature when it comes out of the compressor. After continuously dissipating heat and starting to liquefy, its temperature remains very high. Even after it completely turns into liquid, it continues to dissipate heat to the outdoor air. Indoors, the situation is the opposite. Because it passes through the throttling device, the pressure and temperature of the refrigerant are greatly reduced, and its saturation temperature is also lower than the indoor temperature, which allows it to continuously absorb heat from the indoor air.

The working principle of air conditioning is based on some scientific principles. Learning more can increase our knowledge in this area, especially for air conditioning maintenance personnel, who are very familiar with how air conditioning works. Don’t we feel that air conditioning is really magical? Especially with the advancement of science, our lives are becoming more and more high-tech.