Electronic Expansion Valve: Types, Advantages & Work Principle

What Is Electronic Expansion Valve (EEV)?

EEV meaning electronic expansion valve. The electronic expansion valve (EEV valve) is a kind of expansion device. It is used to adjust the flow of refrigerant entering the refrigeration device according to a preset program.

As a new type of expansion valve, the electronic expansion valve (EEV valve) can optimize the refrigeration system and make the refrigeration system more intelligent. It is applied in more and more HVAC and refrigeration fields. We believe the application of electronic expansion valve (EEV valve)will become more and more mature with the progress and development of technology.

What Is Electronic Expansion Valve In Refrigeration System?

The refrigeration system is composed of refrigeration compressor, condenser, expansion device and evaporator. The expansion valve is one of the most important components in refrigeration system.  

The electronic expansion valve is used to replace thermal expansion valve in some applications, for example, the refrigeration load changes sharply, or the operating range is wide, the traditional expansion device (such as capillary tubes, thermal expansion valves, etc.) can’t meet the requirements, the electronic expansion valve will be the best choice.

What Does Electronic Expansion Valve Kit Compose?

The electronic expansion valve kit (EEV kit) includes an electronic expansion valve, a pressure sensor, a temperature sensor and a electronic expansion valve controller.

EEV Electronic Expansion Valve:

The electronic expansion valve is responsible for controlling the opening of the expansion valve according to the received pulse signal, ensuring the proper amount of liquid supply and proper superheat.

Pressure Sensor:

Detect the evaporation pressure and convert the evaporation pressure value into a current signal, then transmit to the electronic expansion valve controller.

Temperature Sensor:

Detect the evaporation outlet temperature and convert the temperature into a resistance value signal, then transmit to the electronic expansion valve controller.

Electronic Expansion Valve Controller:

EEV controller is one of the most important electronic expansion valve parts. It is the core device of the system, and its function is similar to that of the human brain. The controller can receive the current signal from the pressure sensor and the resistance value signal from the temperature sensor. According to these signals, a pulse signal is sent out through internal calculation to control the opening of the electronic expansion valve, ensuring the liquid supply and superheat of the system.

What is The Electronic Expansion Valve Diagram?

The electronic expansion valve diagram is shown in the figure below:

It takes only a few seconds for the electronic expansion valve (EEV valve) to go from fully closed to fully open. It has the advantages of high accuracy, rapid action. The opening and closing characteristics and speed can be set manually.

What Are The Electronic Expansion Valve Types?

At present, there are mainly two types of electronic expansion valves: electromagnetic expansion valve and electric expansion valve.

The working principles of the two are somewhat different. The electromagnetic expansion valve has an electromagnetic coil inside, and the flow of the system is controlled through the electromagnetic coil as a medium. Before the electromagnetic coil is energized, the valve needle is in the open state. After the electromagnetic coil is energized, the opening degree of the valve needle is controlled by the voltage on the electromagnetic coil. Therefore, the voltage of the electromagnetic coil controls the flow rate of the expansion valve. Electromagnetic expansion The response of the valve is fast, and usually the refrigeration system is always powered on when it is working.

The electric expansion valve is a device driven by a stepping motor. The device controls the movement of the internal thread-driven valve needle through the logic digital signal provided to the stepping motor, thereby realizing the control of the valve flow and area.

How Does Electronic Expansion Valve Working?

When the electronic expansion valve working, the pressure sensor will detect the evaporation pressure and convert the evaporation pressure value into a current signal, then transmit to the electronic expansion valve controller.

The temperature sensor will detect the evaporator outlet temperature and convert the temperature to a resistance value signal, then transmit  to the controller.

According to these signals, it will send our a pulse signal to control the opening of the electronic expansion valve, ensuring the liquid supply and superheat of the system.

What Are the Functions of Electronic Expansion Valve?

The function of the electronic expansion valve (EEV valve) is same as the thermal expansion valve (TXV valve), that is to control the flow of the refrigerant that flows into the evaporator.

What Is The Advantage Of An Electronic Expansion Valve?

The electronic expansion valve features wide adjustment range, low temperature tolerance, remote control and adjustment, energy saving, precise control, fast response and many advantages.

The electronic expansion valve only takes a few seconds to go from fully closed to fully open state, the reaction and action speed is very fast, there is no static superheat phenomenon, and the opening and closing characteristics and speed can be set manually, especially suitable for heat pump units.

For thermal expansion valves, when the ambient temperature is low, the pressure change of the temperature-sensing medium inside the temperature-sensing bulb is greatly reduced, which seriously affects the regulation performance. For electronic expansion valves, the temperature-sensing components are thermocouples or thermal resistors, which are not affected by the ambient temperature. Therefore, the electronic expansion valve can also provide better flow regulation in low-temperature environments such as the freezing room.

The superheat setting value of the electronic expansion valve is adjustable. Just change the source code in the control program to change the set value of superheat. Unlike the thermal expansion valve, which needs to enter the cold storage and adjust on site. The adjustment of the electronic expansion valve can completely realize remote control, and the electronic expansion valve can be adjusted according to different needs. The superheat is flexibly adjusted to reduce the temperature difference between the surface of the evaporator and the environment inside the refrigerator, thereby reducing the frosting on the surface of the evaporator. It not only improves the freezing capacity, but also reduces the dry consumption of food.

The electronic expansion valve is energy saving. If the high and low pressure sides are connected during the shutdown, the refrigerant in the condenser will gradually flow into the evaporator, which will increase the temperature and pressure of the evaporator. When the compressor is turned on again, the additional energy of the compressor needs to be consumed to re-establish the differential pressure. Conversely, if the high and low pressure side is cut off during shutdown, although this maintains the low temperature and low pressure of the evaporator, when it is restarted, the compressor will start with heavy load, and the current will be large, which will also increase energy loss. However, if the electronic expansion valve is used, the above problems will be solved. The specific method is: when shutting down, the expansion valve is fully closed to prevent the refrigerant in the condenser from flowing into the evaporator, causing energy loss when restarting. Before starting up, fully open the expansion valve to balance the high and low pressure sides of the system, and then start up. This not only realizes light-load startup, but also reduces the heat loss during shutdown. In addition, the use of electronic expansion valve can shorten the freezing time. The electronic expansion valve can balance the load and cooling capacity during the whole freezing process, and the freezing efficiency can be improved. The freezing time can also be shortened by 10% compared with the thermal expansion valve.

What is the disadvantage of electronic expansion valve?

The biggest disadvantages of electronic expansion valve is the price and complexity of components. The electronic expansion valve price is higher than thermal expansion valve.

Where Does The Electronic Expansion Valve Located?

The electronic expansion valve (EEV valve) must be installed in the liquid pipeline before the evaporator, and the TXV valve location should be close to the evaporator.

What is the difference EEV vs. TXV?

The electronic expansion valve (TXV) is a mechanical expansion valve, while electronic expansion valve (EEV) is an intelligent expansion valve. The EEV expansion valve can be programmed to work with the other components in the system, optimize the refrigeration system and make the refrigeration system more intelligent.

Which Is Better EEV vs EXV?

EEV vs. TXV, the electronic expansion valve has the advantages of wide adjustment range, low temperature tolerance, remote control and adjustment, energy saving, precise control, fast response. The electronic expansion valve price is also higher than thermal expansion valve.

What brands of expansion valves are there?

There are Danfoss electronic expansion valve, Sporlan electronic expansion valve, Carel electronic expansion valve, Sanhua electronic expansion valve and many other brands.

How do I choose an electronic expansion valve for refrigeration system?

Refrigerant

First of all, it is necessary to determine what refrigerant the electronic expansion valve is used for, such as: R134a, R404A, R407C, R410A, R290 etc.

Cooling capacity

When selecting an electronic expansion valve, it is necessary to select the electronic expansion valve with the corresponding cooling capacity of the refrigeration system.

Glen Refrigeration-Your Best Commercial Refrigeration System Partner

Glen Refrigeration is a leading manufacturer of refrigerator condensing unit, horizontal condensing unit, air cooled condensing unit, water cooled condenser unit, indoor condensing unit, outdoor condensing unit, monoblock refrigeration unit and many other products.

Glen Refrigeration is committed to served our customers high energy efficiency and ECO-friendly condensing units and monoblock refrigeration units, includes inverter condensing unit, R290 condensing unit and hot gas defrost refrigeration system to help our customers lower the operation cost.

If you are not sure which EEV is right for your commercial refrigeration system, that’s no problem. We are ready to help you. Feel free to contact us via email or phone or fill out the contact form below and we’ll hep you find the perfect solution.

Email: info@greehvacr.com

Phone (Whatsapp): 0086 15057108995

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