First, the development of air conditioning.
? At first, air conditioners and refrigerators used toxic gases such as ammonia and methyl chloride. The leakage of this gas will lead to a major accident. Thomas? Midgley invented chlorofluorocarbon gas in 1928 and named it Freon. This refrigerant is much safer for human beings, but it is harmful to the atmospheric ozone layer. Freon is the trademark of DuPont's CF C, HCFC or HFC refrigerants, in which the name of each refrigerant also includes a number to indicate the molecular composition of its components (for example, R- 1 1, R- 12, R-22, R- 134). Among them, R-22 HCFC refrigerant, which is widely used in the field of direct evaporative moderate cooling products, will stop being used in new production equipment from 20 10, and will be completely stopped in 2020. R- 1 1 and R- 12 have been discontinued in the United States. As a substitute, some refrigerants harmless to the ozone layer have been put into use, including those with the trade name? Pulen? R-4 10A。 New environmental protection refrigerants R290 and R32 are gradually entering the market. R290 only contains carbon and hydrogen, but does not contain chlorine and fluorine, and its ozone destruction potential (ODP) is zero.
Second, what is the composition of air conditioning?
? The structure of air conditioner includes: compressor, condenser, evaporator, four-way valve and one-way valve capillary assembly. Working process of specific volume pair between teeth in air-conditioning compressor. The gas on the side where the female screw and the male screw turn is compressed, which is called the high pressure area; On the contrary, when the screw turns to the opposite side, the volume between teeth expands and it is in the suction stage, which is called low pressure area. These two areas are separated by the contact line between the tooth surfaces of the internal thread and the external thread. It can be approximately considered that the plane where the axes of the two screws are located is the boundary surface between the high pressure zone and the low pressure zone. A compressed refrigerant (such as freon) becomes a liquid. Then refrigeration is carried out by using the endothermic phenomenon when the liquid becomes gaseous under normal pressure. The air density is very small. You have an injection. Fill the needle tube with air, block the air outlet by hand and push the needle tube to compress the air. Gas can be compressed by one-third of the volume with a needle tube.
? The compressor sucks the working medium vapor with lower pressure from the evaporator, sends it to the condenser after the pressure rises, condenses it into liquid with higher pressure in the condenser, becomes liquid with lower pressure after throttling by the throttle valve, and then sends it to the evaporator to absorb heat and evaporate it into vapor with lower pressure, thus completing the refrigeration cycle. For some applications, gas must pass through a long tube (usually coiled into a solenoid) to dissipate heat into the surrounding air. Heat conducting metals, such as copper, are often used to transport steam. In order to improve the efficiency of condenser, fins are usually attached to the pipeline to accelerate heat dissipation. The radiator is a flat plate made of metal with good thermal conductivity.
? Evaporator is the interior of indoor unit, which consists of pipes covered with fins. A device that concentrates a solution by heating or precipitates grains from the solution. It mainly consists of a heating chamber and an evaporation chamber. The heating chamber provides the heat needed for evaporation to the liquid, and promotes the liquid to boil and evaporate; The evaporation chamber completely separates the gas phase from the liquid phase. The steam generated in the heating chamber carries a large amount of liquid foam, which can be separated from the steam by self-condensation or demister after reaching the evaporation chamber in a larger space. Four-way valve, hydraulic valve term, is a control valve with four oil ports. Four-way valve is an indispensable component in refrigeration equipment. Its working principle is that when the solenoid valve coil is in the power-off state, the pilot slide valve is driven by the right compression spring to move to the left, and the high-pressure gas enters the capillary ① and then enters the right piston cavity. On the other hand, the gas in the left piston chamber is exhausted. Due to the pressure difference between the two ends of the piston, the piston and the main slide valve move to the left, so that the exhaust pipe is communicated with the nozzle of the outdoor unit, and the other two nozzles are communicated to form a refrigeration cycle.
? The above introduction about the development and composition of air conditioning is here for you. Speaking of air conditioning, it can be popularized, mainly through cinemas. Most Americans are exposed to air conditioning in cinemas. In the 1920s, cinemas used air-conditioning technology, promising to provide cool air for the audience, making air-conditioning as attractive as the film itself, and summer replaced winter as the peak season for watching movies. Subsequently, a large number of indoor entertainment places such as casinos, indoor gymnasiums and shopping malls opened all year round, all thanks to the appearance of air conditioning.