The working principle of air conditioner and refrigerator is basically the same, and they are all composed of compressor, condenser, evaporator and throttling device. The working principle is that the low-pressure steam of refrigerant in the refrigeration system is sucked by the compressor, compressed into high-pressure steam, and then discharged into the condenser. At the same time, the outdoor air sucked by the axial fan flows through the condenser, taking away the heat released by the refrigerant and condensing the high-pressure refrigerant vapor into high-pressure liquid. The high-pressure liquid is injected into the evaporator after passing through the filter and throttling mechanism, and evaporates at the corresponding low pressure to absorb the surrounding heat. At the same time, the cross-flow fan makes air continuously enter the fins of the evaporator for heat exchange, and sends the cooled air after heat release to the room. In this way, the indoor air continuously circulates and flows to achieve the purpose of cooling down. The refrigerator has no fan and relies on natural convection for heat exchange. The refrigerator has no fan and relies on natural convection for heat exchange. As a refrigerator, it only reduces the temperature in the sealed cabinet to a certain set value, while for air conditioners, in order to reduce the indoor temperature, the excess heat in the room must be discharged to the outside, so the compressor and radiator must be outdoors. When we passed the air conditioner in summer, we felt hot air blowing out, which was the reason.
Heat transfer is called heat transfer for short. As long as there is a temperature difference inside or between objects, heat will spontaneously transfer from high temperature to low temperature. Temperature difference is ubiquitous in daily life and industrial production in nature, so heat transfer has become a very common physical phenomenon. The heat transfer law is studied, that is, according to different heat transfer processes, the relationship between the heat transferred per unit time and the corresponding temperature difference is obtained. Different heat transfer modes have different heat transfer laws and corresponding research and analysis methods are also different.
Heat transfer is widely used in various fields of science and technology. Although various forms of heat transfer problems will be encountered in various fields, the purpose of studying heat transfer can be roughly summarized into three aspects.
(1) Strengthen heat transfer and increase the transferred heat under certain conditions (such as certain temperature difference, volume, weight or pumping power, etc.). ).
(2) weaken heat transfer or heat preservation, that is, minimize heat transfer at a certain temperature difference.
(3) Temperature or heat transfer control, in order to make some equipment run safely and economically, or to obtain high-quality products and processes, it is necessary to control the temperature or heat transfer rate of key parts of the object during heat transfer.