What Are the Different Types of Expansion Valves

There are many types of expansion valves available for use in refrigeration and air conditioning systems.

Different types of refrigeration and air conditioning systems have expansion valves with different shapes and functions.

Each with its features and benefits. For example, variable frequency compressors should use electronic expansion valves, and fixed frequency compressors should use thermal expansion valves or capillary tubes.

We will talk about all of them one by one, but the most common and available four types are Thermostatic Expansion Valve in HVAC&R, Automatic Expansion Valve, Electronic Expansion Valve, and Capillary Tube Expansion Valve.

We will focus on these four types of expansion valves.

Warm tip: Before reading this blog, you should understand what a refrigeration system is and how an expansion valve works.

Thermostatic Expansion Valve (TXV):

The thermostatic expansion valve is one of the earliest expansion valves invented, and this type of expansion valve is mainly used in refrigeration and air conditioning systems, also known as HVAC&R systems. (Learn what is thermostatic expansion valve and What is Internal and External Equalizer Expansion Valves (TXV) are in this blog).

Because of its mechanical construction thermostatic expansion valves.

So it has the best reliability of any expansion valve of its type.

This is why thermostatic expansion valves have the highest market share and are used in a wide range of applications.

Thermostatic expansion valves can be used for transport refrigeration units, cold room refrigeration units, semi-hermetic condensing units, walk-in cooler refrigeration units, Copeland scroll outdoor condensing units, Commercial outdoor refrigeration units, heat pumps drying machines, swimming pool heat pumps, etc.

The fields involved in the thermostatic expansion valve include cold storage, transportation refrigeration, medicine, food, supermarkets, air conditioners, heat pumps, etc.

Because the market demand for thermostatic expansion valves is huge, there are many brands of thermostatic expansion valves. Such as Danfoss(Denmark), Emerson(US), Saginomiya(Japan) Sanhua(China), Sporlan(US), STF(China), DUNAN(China), Sina(China), etc.

If you have a purchasing demand, please contact us now, and we can supply you the genuine thermostatic expansion valves.

Electronic Expansion Valve (EEV or EXV):

With the development of split refrigeration compressors and air conditioning compressors, the rise and development of electronic expansion valves have been promoted.

The development of compressors and electronic expansion valves has promoted the development of split air conditioners and central air conditioners.

Check out the different brands of compressors to learn more. (Copeland, Panasonic, Hitachi, Mitsubishi, GMCC, Daikin, etc.).

In the household market, people have very high requirements for comfort.

Traditional capillary expansion valves and thermal expansion valves cannot meet people’s needs, so the electronic expansion valve was born.

The electronic expansion valve is controlled electronically, which achieves precise control of the refrigerant flow.

Compared with mechanical thermostatic expansion valves, electronic expansion valves have the advantages of precise temperature control, wide temperature adjustment range, and rapid response.

Click to learn more about the “Difference between Thermostatic Expansion Valve and Electronic Expansion Valve“.

As soon as the electronic expansion valve was born, it quickly occupied the air conditioning market and replaced the traditional thermostatic expansion valve.

Click to learn what is an electronic expansion valve.

Capillary Tube Expansion Valve:

The capillary tube is the most economical, lowest cost, and lowest failure rate expansion valve. (Check what is a capillary tube in HVAC&R?)

In which refrigeration equipment do you think a capillary tube expansion valve will be used?

The answer is that capillary tube expansion valves are almost everywhere.

It exists in all small refrigeration equipment, such as small refrigeration units, remote condensing units, drop-in refrigeration units, self-contained refrigeration units, vending machine units, etc.

By inspecting these small refrigeration equipment, did you find anything in common?

What they have in common is a small cooling capacity, small volume, and constant cooling temperature.

Yes, there is no problem when the capillary tube is used as an expansion valve in refrigeration equipment.

However, some air conditioning manufacturers also use capillary tubes in the design of split air conditioners.

You can clearly understand this in the working principle of the capillary tube.

The application of capillary tubes in air conditioning systems will reduce the performance of the air conditioner and increase energy consumption.

Daily operation is higher than that of air conditioners using electronic expansion valves.

But air conditioners using capillary tubes are very cheap. This requires you to make a balance in your choices.

Automatic Expansion Valve (AEV):

The difference between an automatic expansion valve and a thermostatic expansion valve is that a TXV doesn’t have an external thermal sensing device.

An automatic expansion valve adjusts the valve opening according to the evaporator pressure, maintaining a constant superheat.

It utilizes a pressure-actuated diaphragm to ensure a consistent pressure within the evaporator is maintained.

An automatic expansion valve is mostly used in HVAC&R applications where the load is constant.

Air conditioning system commonly has frequent fluctuations during operation, which makes it less suitable for this valve.

However, automatic expansion valves can be used in other constant temperature applications like milk chilling units, ice breakers, home freezers, and small commercial refrigeration units.

Manual Expansion Valve:

A manual expansion valve is a valve in which the valve opening needs to be operated and adjusted manually by a fixed-positioned needle.

It is typically used as a safety valve in some older, simpler systems or bypass lines.

It is unresponsive to load fluctuations and almost impossible to adjust instantly by hand.

It is the least common type of expansion valve and less popular because of its less precision methods compared to other automatic and advanced expansion valves in HVAC.

Float Expansion Valve:

An HVAC  float expansion valve is normally located between the liquid receiver and the evaporator. It can preciously adjust the refrigerant system’s refrigerant flow.

Except for refrigeration, it also regulates the refrigerant flow in air conditioning systems and other HVAC applications by throttling and reducing the pressure from the refrigerant.

A float expansion valve is another type of dynamic expansion valve that contributes to the precise regulation of refrigerant levels in both evaporator and condenser using a float submerged in the liquid refrigerant.

This valve works in both low-side and high-side float devices to control the liquid refrigerant flow, though the role is different.

HVAC float expansion valve is mainly used in large-scale refrigeration equipment, such as industrial refrigeration applications, large-scale water-cooled central air-conditioning applications, etc.

Car AC Expansion Valve:

A car AC expansion valve plays the same role as the one in the expansion valve in the HVAC system.

The AC AC expansion valve controls the refrigerant quantity and speed. It changes the high-temperature, high-pressure liquid refrigerant into low-pressure liquids.

And the main purpose is to make the car air conditioner cycle work.

It regulates & controls the refrigerant flow by controlling pressure and temperature and maintains effective air conditioning performance in cars and other vehicles.

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