What Is the Difference Between TXV and EEV

In chiller projects, one question comes up again and again. Should the system use TXV or EEV. At first the two devices look alike. Both are expansion valves and both decide how much refrigerant goes into the evaporator.

But the way they do the job feels completely different once you see them in action. This difference can change how stable the cooling is, how much power the machine draws, and even how often service calls are needed.

What Is a TXV

The full name is Thermostatic Expansion Valve. It has been around for decades and many old installations still run on it today.

A TXV is fully mechanical. There is a small bulb filled with refrigerant that senses the temperature at the evaporator outlet. When the load rises the bulb warms up, pressure inside the bulb increases, and the diaphragm inside the valve pushes open the needle. More refrigerant enters the evaporator. When the load falls the opposite happens and flow is reduced.

The beauty of a TXV lies in its simplicity. No wires, no controller, no power supply. A technician can carry one in the toolbox, install it within an hour, and the system will work. For chillers that run under stable conditions, this can be more than enough.

Still, the control is not very sharp. Small mistakes in bulb placement or wear inside the valve can affect performance. In plants where the load changes fast, TXV often feels a bit slow to react.

What Is an EEV

EEV means Electronic Expansion Valve. This design belongs to the digital age. Instead of a bulb it uses sensors. Instead of a spring it uses a stepper motor. The valve works together with a controller that constantly checks pressure, temperature, and superheat. Every few seconds, sometimes even faster, the controller tells the motor how much to open or close.

Because of that, EEV brings a level of accuracy that a TXV cannot match. The flow of refrigerant is adjusted in very small steps. In a test room we once saw an EEV making thousands of micro corrections while the system load jumped up and down. The evaporator stayed stable the whole time.

That level of precision means better energy efficiency, more protection for the compressor, and smoother operation in processes where temperature cannot drift.

Key Differences Between TXV and EEV

1.Working Principle

TXV depends on mechanical force. The bulb expands and contracts with temperature, and that motion pushes the valve open or shut. Everything happens inside the valve itself.

EEV depends on electronics. Sensors collect information, the controller calculates the required condition, and the stepper motor positions the valve accordingly.

2.Control Method

TXV reacts to a single factor, the bulb temperature. If the load changes quickly it may take a while before the valve reaches the right position.

EEV takes multiple signals at once. Temperature, pressure, even system trends can be considered. It does not only react, it adjusts ahead of time to keep the system stable.

3.Control Accuracy

TXV keeps superheat in a safe range, but it is not always precise. If the bulb loses thermal contact, the valve may feed too much or too little refrigerant.

EEV is far more exact. It can hold superheat within a very narrow window. This level of control reduces the chance of liquid refrigerant washing back to the compressor and increases efficiency.

4.Response Speed

The response of TXV is tied to how fast the bulb changes temperature. That means there is a delay when the load swings.

The response of EEV is almost instant. The motor moves quickly in small steps as soon as the sensors report new conditions. In systems with unstable loads, this quick reaction makes a visible difference.

5.Application

TXV is still a solid choice for commercial air conditioning, supermarket refrigeration, or chillers running under steady load. In remote locations where electronics may be difficult to support, TXV gives peace of mind.

EEV finds its place in high precision industries. Semiconductor plants, pharmaceutical factories, and data centers rely on tight temperature control, and EEV fits that need. Energy saving projects also lean toward EEV, since even a few percent of efficiency can justify the higher price.

6.Cost

TXV costs less. The valve itself is cheaper, installation is simple, and almost every technician knows how to replace one.

EEV costs more, not only the valve but also the sensors and controller. Service requires a technician who understands electronics. However, many operators find that lower energy bills and longer equipment life cover the difference in price within a reasonable period.

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What is the Difference Between TXV and EEV - EEV（images 2）

Conclusion

TXV remains the reliable workhorse, simple and affordable, especially where conditions do not change much. EEV is the modern solution, fast, precise, and efficient, built for industries where control is critical.For some systems TXV is more than enough. For others, only EEV can deliver the performance required.

Most of LNEYA’s chillers use the more precise EEV to meet the stringent temperature control requirements of industries such as semiconductors, pharmaceuticals, and chemicals. However, if you require a TXV, we can also customize it to your needs.

Let us know your requirements