High-temperature heat transfer fluids have proven their worth in a variety of industrial processes – from chemical processing and plastic manufacturing to concentrated solar power and food processing equipment.
Not only are high-temperature heat transfer fluids key to the regulation of temperatures, but they are also important for ensuring critical components operate as they should.
In this article, we ask what the most important considerations are when selecting one of these specialised fluids for your industrial processes.
The role of high-temperature heat transfer fluids
High-temperature heat transfer fluids typically consist of synthetic oils, silicone-based fluids or specialised chemical formulations that are designed to operate at elevated temperatures.
Where water-based coolants would fail, the primary advantage of high-temperature heat transfer fluids is their ability to be stable and perform under extreme thermal conditions.
The different industrial applications that these fluids are used for present a diversity of operating environments. That’s why premier high-temperature heat transfer fluids on the market, such as the Paratherm range, offer a series of solutions for providing reliable thermal management in varying industrial scenarios.
Selecting a heat transfer fluid
Let’s put the spotlight on some key considerations when choosing a heat transfer fluid.
Temperature range
One of the most critical factors is selecting the right operating temperature range. This is fundamental in enabling your fluid to maintain stability throughout your system’s temperature spectrum – from cold startup to maximum operating temperature.
Different formulations offer various temperature capabilities. Some Paratherm fluids have a minimum temperature below freezing, while others start from above 0 ℃. Maximum operating temperatures also vary within the 300-350℃ range.
Selecting a fluid with an appropriate temperature range prevents premature degradation and system efficiency losses.
Thermal stability
Thermal stability refers to a fluid’s resistance to molecular breakdown under heat stress. A thermally stable fluid resists cracking, oxidation and polymerisation when exposed to high temperatures for extended periods.
Compatibility
Your chosen fluid must be compatible with all system materials, including metals, gaskets, seals and pipe materials. Incompatibility may lead to corrosion, degraded seals and potential system failures.
Consult compatibility charts provided by manufacturers like Paratherm to confirm that your selected fluid works harmoniously with all system components.
Fluid life
Service life directly impacts your operational costs and maintenance schedules. Premium high-temperature fluids may require higher initial investment but often deliver superior longevity and performance stability.
Paratherm’s formulations are engineered for extended service life, with some products offering years of reliable operation before replacement becomes necessary, provided proper maintenance protocols are followed.
Coefficient of thermal expansion
We’ve provided an overview of the fundamental factors when considering high-temperature heat transfer fluids, but there are other important characteristics that shouldn’t be ignored.
One of these is the coefficient of thermal expansion. All fluids expand when heated and contract when cooled. The coefficient of thermal expansion quantifies this property and is particularly important in closed-loop systems where changes in volume must be accommodated.
Systems using fluids with high expansion coefficients require appropriately sized expansion tanks. Paratherm provides detailed expansion data for its product range, enabling proper system design and avoiding overpressure.
Flash point and ignition temperature
Safety is paramount when selecting high-temperature fluids. The flash point (temperature at which vapours can ignite with an ignition source) and auto-ignition temperature (temperature at which spontaneous combustion occurs) are critical safety parameters.
Paratherm offers fluids with varying flash points to accommodate different safety requirements, including high flash point options for applications where fire risk must be minimised.
Viscosity
Viscosity – that is, an oil’s level of resistance to flow and shear – will dictate pumping requirements, heat transfer efficiency, and system pressure drops.
An ideal heat transfer fluid will maintain a suitable viscosity across its operating temperature range. This will make it fluid enough for efficient pumping at startup temperatures, but also stable enough at maximum operating temperatures.
Pressure rating
System operating pressure and the fluid’s vapour pressure at maximum operating temperature both need to be considered. If system pressures fall below the fluid’s vapour pressure, boiling will occur. This may lead to cavitation, pump damage and reduced heat transfer efficiency.
Specific heat capacity
A heat transfer fluid’s ability to store thermal energy is important to a system working as it should.
Higher specific heat capacity means more thermal energy can be transported per unit volume of fluid. This reduces pumping requirements and improves the overall performance of a system.
Making the right choice
When selecting a high-temperature heat transfer fluid for your industrial application, diligently check each system requirement has been satisfied.
Budgetary considerations may influence your final decision, but product characteristics that affect safety, system reliability and maintenance costs should not be compromised.
