Overview of the DunAn Thermostatic Expansion Valve Range
Thermostatic Expansion Valves (TEVs) are integral components in refrigeration and HVAC systems, serving to regulate the flow of refrigerant into the evaporator and maintain the correct superheat. DunAn, a leading manufacturer of these valves, offers a range of models, each designed for specific applications and systems. Understanding the different series available—TA, TAE, TI, TIE, TCE, and TCBE—can help you choose the right valve based on system requirements and performance needs.
The TA and TAE series are designed for general refrigeration and air conditioning applications, as well as ice makers and heat pumps. These valves regulate refrigerant flow into small and medium-sised evaporators by sensing the temperature at the evaporator outlet. The TA series offers both fixed and adjustable superheat versions, allowing for flexibility depending on the system's needs. It is available in both straightway and angleway designs, with options for external equalisation and bleed functions. These features ensure the TA valves maintain stable operation, reducing the risk of system fluctuations. Additionally, they support multiple refrigerants, such as R134a, R404A, and R407C, making them suitable for a broad range of commercial and residential applications. The TAE series, similar in functionality, is designed for slightly more specific uses in refrigeration and air conditioning systems that require more precise superheat control.


Moving on to the TI and TIE series, these valves are ideal for systems that require more robust operation, including refrigeration, ice machines, heat pumps, and air conditioners. The TI series is noted for its interchangeable orifice assembly, which allows for easy capacity matching and storage, making it highly adaptable to various refrigeration systems. The TIE series, often referred to as the "enhanced" version, includes additional features such as higher pressure ratings and more specialised configurations for complex systems. Both the TI and TIE valves come with options for an MOP (Maximum Operating Pressure), and they are compatible with a wide range of refrigerants, including R22, R134a, and R404A. These series are often selected for commercial applications where consistent performance and high-pressure handling are crucial.


The TCE and TCBE series are designed for larger capacity systems, making them well-suited for high-demand applications like central air conditioning systems, heat pumps, and chillers. These valves feature a straightway design, which allows for a more direct flow of refrigerant, reducing resistance and improving overall efficiency. Both series are available with adjustable superheat, ensuring precise control over the refrigerant flow to maintain optimal system performance. The TCBE series includes a bi-flow design, which is especially useful in systems that require both cooling and heating capabilities, such as heat pumps. Both series can be equipped with an MOP function for added protection against excessive pressures, and they also include a bleed function to ensure smooth operation even under fluctuating load conditions.


An important feature across many of the DunAn TEV ranges is external equalisation, which helps improve the valve's responsiveness to pressure changes within the system. This is particularly useful in systems where the evaporator experiences variable pressure conditions, allowing the TEV to better adjust refrigerant flow in response to these changes. The bleed function, found in some models, allows a small amount of refrigerant to continuously flow through the valve, helping prevent issues such as hunting, which can occur when the valve rapidly opens and closes due to superheat fluctuations.
Overall, each DunAn TEV series is optimised for specific applications, offering a range of options such as straightway and angleway designs, bi-flow configurations, adjustable superheat, and external equalisation to suit various refrigeration and HVAC systems. Whether you are working with small residential air conditioning units or large industrial chillers, understanding the nuances of these valve models ensures you select the right one to maintain system efficiency, reduce pressure issues, and improve overall performance. With multiple refrigerant compatibility and the ability to handle a wide range of operating conditions, these valves are a reliable choice for any commercial or residential refrigeration system.