What is the Principle of an Expansion Valve?
2 Answers
The working principle of an expansion valve involves detecting and collecting multiple parameters such as superheat, the temperature difference between inlet and outlet air, return air temperature, and their set values. After processing by a microprocessor, it issues commands to control the opening degree of the electronic expansion valve to meet the system load requirements. Below is a related introduction to expansion valves: 1. Installation Location: The expansion valve is an important component in the refrigeration system, typically installed between the liquid receiver and the evaporator. 2. Principle: The expansion valve converts medium-temperature, high-pressure liquid refrigerant into low-temperature, low-pressure wet steam through throttling. The refrigerant then absorbs heat in the evaporator to achieve the refrigeration effect. The expansion valve controls the valve flow rate based on changes in superheat at the end of the evaporator, preventing insufficient utilization of the evaporator area and knocking phenomena.
The expansion valve plays a crucial role in a car's air conditioning system. I learned about it through auto repair—it acts like a regulating switch, controlling the refrigerant's transition from high-pressure liquid to low-pressure gas. When the refrigerant passes through the valve, the pressure drops sharply, causing the liquid to expand and evaporate into gas, absorbing heat from around the evaporator and cooling the hot air inside the car. This principle ensures effective cold air output from the AC. If the expansion valve fails, the refrigerant flow becomes unbalanced, leading to insufficient cooling or a non-functional AC. I've seen many car owners complain about hot air blowing from the AC in summer, often due to a clogged or stuck expansion valve. Remember, the expansion valve must work in coordination with the compressor and condenser, collectively impacting AC efficiency and fuel consumption, making regular checks essential.
