Which type of metering device is commonly used in a 12 SEER split air conditioning system?

In a 12 SEER split air conditioning system, the thermostatic expansion valve (TXV) is commonly used as the metering device. The TXV plays a crucial role in regulating the flow of refrigerant into the evaporator coil, which allows for precise control of the cooling process. This is particularly important in maintaining the efficiency and performance of the air conditioning system, as it helps to optimize the amount of refrigerant that evaporates based on the cooling demand.

The TXV adjusts the refrigerant flow based on the temperature and pressure at the outlet of the evaporator, ensuring that the system provides consistent cooling while preventing issues such as liquid refrigerant returning to the compressor. This mechanism enhances the overall SEER rating (Seasonal Energy Efficiency Ratio) of the system, which is a measure of its efficiency in converting electrical energy into cooling.

While capillary tubes and expansion valves are also types of metering devices, they do not offer the same level of precision or adaptability as the TXV, especially in systems designed to meet or exceed specific efficiency standards like a 12 SEER system. The centrifugal valve does not apply in this context, as it is not used in standard split air conditioning systems but rather in different kinds of fluid dynamics applications.