thermic fluid

Introduction to Thermic Fluid​
A thermic fluid, also known as a heat – transfer fluid, is a substance used to transfer thermal energy from a heat source to a point of use or vice versa in heat – transfer systems. These fluids are designed to efficiently carry and distribute heat, enabling processes that require precise temperature control, such as chemical reactions, food processing, and industrial manufacturing. Thermic fluids can operate over a wide range of temperatures, from sub – zero conditions for cooling applications to high – temperature environments exceeding 300°C for heating processes. Their versatility and effectiveness make them indispensable in numerous sectors where heat management is critical.​

Types of Thermic Fluids​
Synthetic Thermic Fluids​
Synthetic thermic fluids are engineered to meet specific performance requirements. They are often formulated to have excellent thermal stability, allowing them to operate at high temperatures without significant degradation.​
Aromatic – Based Fluids: These synthetic fluids are characterized by their high – temperature resistance and good heat – transfer capabilities. They are commonly used in applications where temperatures can reach up to 350°C or more, such as in chemical plants for heating reactors. Aromatic – based fluids have low volatility, which reduces the risk of fluid loss through evaporation, and they also exhibit good chemical stability, making them suitable for use in systems where contact with various chemicals may occur.​
Silicone – Based Fluids: Silicone – based thermic fluids offer a wide operating temperature range, from extremely low temperatures (down to – 60°C) to relatively high temperatures (up to 200 – 250°C). They are known for their excellent thermal stability, low toxicity, and resistance to oxidation. Silicone fluids are often used in applications where a non – flammable and chemically inert heat – transfer medium is required, such as in food processing equipment or in sensitive electronic cooling systems.​
Mineral – Based Thermic Fluids​
Mineral – based thermic fluids are derived from petroleum and are widely used due to their relatively low cost and availability.​
Paraffinic Fluids: Paraffinic mineral fluids have good thermal properties and are suitable for a range of moderate – temperature applications, typically up to around 250°C. They have a relatively low viscosity, which facilitates easy pumping and circulation within the heat – transfer system. Paraffinic fluids are commonly used in industrial heating applications, such as in textile manufacturing for heating dyeing machines.​
Naphthenic Fluids: Naphthenic mineral fluids offer better low – temperature fluidity compared to paraffinic fluids, making them suitable for applications where the fluid needs to operate at lower temperatures without thickening or solidifying. They also have good oxidation resistance and can be used in systems with a temperature range of up to approximately 200 – 220°C. Naphthenic fluids are often employed in heating systems for small – scale industrial processes or in commercial buildings.​

Other Types of Thermic Fluids​
Molten Salts: Molten salts are used in high – temperature applications where temperatures can exceed 500°C. They have high heat – capacity and excellent thermal stability at elevated temperatures. Molten salts are commonly used in concentrated solar power plants, where they are heated by concentrated sunlight and then used to generate steam for power generation. Their ability to store thermal energy for extended periods makes them ideal for ensuring continuous power production even when the sun is not shining.​
Water – Glycol Mixtures: Water – glycol mixtures are widely used as thermic fluids in cooling applications. The addition of glycol (such as ethylene glycol or propylene glycol) to water lowers the freezing point of the mixture, making it suitable for use in cold environments. Water – glycol mixtures are commonly used in automotive cooling systems, industrial refrigeration units, and HVAC (Heating, Ventilation, and Air Conditioning) systems for buildings.​
Properties of Thermic Fluids​
Thermal Stability​
Thermal stability is a crucial property of thermic fluids, especially for high – temperature applications. A thermally stable fluid can withstand repeated heating and cooling cycles without decomposing or forming deposits. Synthetic thermic fluids are generally designed to have superior thermal stability compared to mineral – based fluids, allowing them to operate at higher temperatures for longer periods. Degradation of the thermic fluid due to poor thermal stability can lead to reduced heat – transfer efficiency, increased viscosity, and potential damage to the heat – transfer system components.​
Viscosity​
The viscosity of a thermic fluid affects its flow characteristics within the heat – transfer system. A fluid with low viscosity flows more easily, reducing the energy required to pump it through the pipes and minimizing pressure drops. However, if the viscosity is too low, it may lead to reduced film strength in heat – exchanger surfaces, affecting heat – transfer efficiency. On the other hand, a fluid with high viscosity can cause increased pumping power requirements and may result in poor circulation. The ideal viscosity of a thermic fluid depends on the specific operating conditions of the system, including temperature, flow rate, and pipe diameter.​
Flash Point and Fire Point​
The flash point and fire point are important safety properties of thermic fluids, especially for flammable fluids. The flash point is the lowest temperature at which the fluid can produce enough vapor to ignite briefly when exposed to an open flame. The fire point is the temperature at which the fluid will continue to burn once ignited. Fluids with higher flash and fire points are generally safer to use, as they pose a lower risk of fire or explosion. In industrial applications where safety is a top priority, such as in chemical plants or refineries, thermic fluids with high flash and fire points are preferred.​
Chemical Compatibility​
Thermic fluids need to be chemically compatible with the materials of construction of the heat – transfer system, including pipes, pumps, heat exchangers, and seals. Incompatibility can lead to corrosion of metal components, degradation of seals, and the formation of deposits or sludge within the system. For example, some thermic fluids may react with certain metals, such as copper or aluminum, causing corrosion over time. Therefore, it is essential to select a thermic fluid that is compatible with the materials used in the specific heat – transfer system to ensure its long – term reliability and performance.​
Applications of Thermic Fluids​
Thermal Liquid Heating Systems​
In thermal liquid heating systems, thermic fluids are used to transfer heat from a heat source, such as an electric heater or a fired heater, to the process or equipment requiring heating. These systems are widely used in industries like chemical processing, food production, and manufacturing. For instance, in a chemical plant, a synthetic thermic fluid with high – temperature stability may be used to heat reactors where chemical reactions take place. The fluid absorbs heat from the heater and then transfers it to the reactors, maintaining the precise temperature required for the reactions to proceed smoothly.​
Cooling Systems​
Thermic fluids also play a role in cooling systems, where they are used to remove heat from equipment or processes. Water – glycol mixtures are commonly used in automotive cooling systems to absorb heat from the engine and transfer it to the radiator, where it is dissipated into the atmosphere. In data centers, specialized thermic fluids are used in liquid – cooling systems to cool high – performance servers, ensuring their optimal operation by preventing overheating.​
Power Generation​

In power – generation applications, such as concentrated solar power plants and some industrial waste – heat recovery systems, thermic fluids are used to transfer and store thermal energy. In concentrated solar power plants, molten salts are heated by concentrated sunlight in a receiver. The hot molten salt then transfers its heat to a working fluid, which generates steam to drive a turbine and produce electricity. The ability of molten salts to store thermal energy allows for continuous power generation even when the sun is not shining, enhancing the reliability of the power – generation process.​
Selection and Maintenance of Thermic Fluids​
Selection​
Selecting the appropriate thermic fluid for a specific application involves considering several factors. The required operating temperature range is a primary consideration. For high – temperature applications, synthetic thermic fluids with excellent thermal stability are often preferred, while for lower – temperature or cooling applications, water – glycol mixtures or naphthenic mineral fluids may be more suitable. Chemical compatibility with the system materials, the fluid’s viscosity at operating temperatures, and safety properties such as flash point and fire point also need to be evaluated. Additionally, environmental factors, such as the fluid’s toxicity and biodegradability, may influence the selection, especially in applications where environmental regulations are strict.​
Maintenance​
Regular maintenance of thermic fluids is essential to ensure the efficient and reliable operation of heat – transfer systems. This includes periodic monitoring of the fluid’s properties, such as viscosity, acidity, and thermal stability. Fluid samples should be analyzed regularly to detect any signs of degradation or contamination. If the fluid’s properties deviate from the acceptable range, it may need to be treated, such as by adding additives to improve its performance, or replaced entirely. The heat – transfer system should also be inspected for leaks, as fluid loss can not only reduce the system’s efficiency but also pose safety and environmental risks. Additionally, proper storage of thermic fluids is important to prevent contamination and degradation before use.​
In conclusion, thermic fluids are essential components in heat – transfer systems across a wide range of industries. Understanding their types, properties, applications, selection criteria, and maintenance requirements is crucial for optimizing heat – transfer processes, ensuring system efficiency, and promoting safe and sustainable operations. As industries continue to evolve and demand more efficient and environmentally friendly heat – management solutions, the role of thermic fluids will remain significant, driving further advancements in fluid technology and system design.