In a refrigeration system, the metering device receives high-pressure refrigerant liquid from the condenser. This device regulates the flow of refrigerant into the evaporator, lowering its pressure and temperature, which allows it to absorb heat from the surroundings. The refrigerant then evaporates, turning into a gas as it cools the area being conditioned.
the pressure of the refrigerant drops significantly as it passes through the metering device. This sudden pressure drop causes the refrigerant to expand and vaporize, leading to the flash gas phenomenon. This phase change from liquid to gas helps lower the temperature of the refrigerant as it enters the evaporator coil.
when the refrigerant passes through the metering device, some of it starts to flash from a liquid to a gas because
The refrigerant is in a liquid state as it enters the expansion device.
As the refrigerant exits the metering device
Most refrigerators use a capillary tube as the refrigerant metering device. It is a simple and cost-effective way to regulate the flow of refrigerant into the evaporator coil.
Not enough refrigerant, restriction on the metering device.
superheated vapor
A metering device on a refrigerator is usually a capillary(cap)tube. It is a very small copper line located somewhere between the condenser coils (outside-hot) and the evaporator coils (cooling coils). It reduces the pressure of the refrigerant coming from outside as it enters the evap coils inside. Refrigerant cools under low pressure thus cooling desired inside area when air is blown across the cold coils. Think of a kinked garden hose and how on the spicket side of the hose the pressure is great, but on the other side the pressure is decreased. That is basically the purpose of a metering device.
The narrow tube used as a metering device in refrigeration and air conditioning systems is called a capillary tube. It helps to regulate the flow of refrigerant into the evaporator coil to control the cooling process.
The most commonly used metering device in small air conditioners is the capillary tube. It is a simple and cost-effective device that regulates the flow of refrigerant into the evaporator coil, helping to achieve efficient cooling.
Metering device The metering device controls the flow of liquid refrigerant through the system. The liquid enters at a high-pressure, high-temperature, sub-cooled state and leaves as a low-pressure, low temperature, expanded liquid state. Accurator Piston and Thermostatic Expansion Valves are the most widely used metering devices. Accurator Pistons are widely used because of their low cost and flexibility. The piston can easily be changed to match the capacity of the condensing unit. The Thermostatic Expansion Valve (TXV) is the most efficient type of metering device. The TXV automatically adjusts the flow of the liquid refrigerant based on the superheat of the refrigerant leaving the evaporator coil. As the load on the evaporator increases, the TXV increases the flow of refrigerant. This maintains the proper superheat. The TXV is efficient throughout a variety of system operating conditions, while the accurator is efficient only under designed conditions.
The high pressure (discharge) side starts at the compressor outlet and ends at the metering device inlet. This side will have the smaller refrigerant lines. The low pressure (vacuum) side begins at the metering device outlet and ends at the compressor inlet. This side will have the larger refrigerant lines.