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Types of Refrigerant Flow Control

Jaime Lutz

Refrigerant flow control is used to fine-tune the temperature in refrigerant devices by maintaining an optimal flow of refrigerant into its evaporator.

Types of Refrigerant Flow Control

Refrigerant flow control technology is used in everything from air conditioners to refrigerators in order to keep stable, cooled temperatures in closed areas. Refrigerants trap and release heat over a controlled period of time, which keeps cars, fridges and homes cool. But to conserve energy, refrigerants are aided by flow controls, which also keep cooling devices from flooding with refrigerant. Flow controls – typically valves – are used now to fine-tune the temperature in refrigerant devices by maintaining an optimal flow of refrigerant into its evaporator at all times. The following are some of the flow controls used in these refrigerant technologies.

Thermostatic Expansion Valve

Many air conditioners now use thermostatic expansion valves as their standard metering device because they're efficient and precise while being relatively inexpensive. These valves regulate the flow at which liquid refrigerant flows into the evaporator by regulating the flow rate against the evaporation rate. This is measured by the valves through monitoring the pressure in the evaporator and the temperature of the refrigerant as it evaporates. Thermostatic expansion valves aren't, however, designed to control air temperature, head pressure, capacity, suction pressure or humidity, and they can malfunction if used in such a way. And they're generally less precise compared to electronic expansion valves, in part because their compressor performance worsens during high and low loads. However, they're still widely used and generally considered reliable by industry professionals.

Electronic Expansion Valve

Electronic expansion valves are more consistent and precise than thermostatic expansion valves, but they are also more expensive. These valves calculate the temperature at which the system overheats (and often the pressure in the evaporator) and manage the opening and closing of the valve based on these variables. They can also easily adapt to different types of refrigerant fluid by changing their variables, which is possible with a thermostatic expansion valve but is often far more complicated.

Solenoid Valve

A solenoid valve uses an electromagnet to control the flow of liquids or gases, mainly refrigerants in HVAC systems. In these valves, an electrified coil becomes magnetized and causes a plunger to stop the flow through the valve; when it's demagnetized, the flow resumes. This flow can be controlled by a simple switch on the device. These valves are fast, reliable and sturdy, but their main advantage is that they can be placed in remote locations on a device, making them a compact and easy fit.