How Thermal Fluid Heating Works and How to Manage It

Thermal fluid heating is an integral component of many industrial applications worldwide. These systems have mostly replaced boilers thanks to the flexibility and control thermal heating offers. With that said, it’s helpful to understand how they work. This post will examine how thermal fluid heating works and what products best facilitate it. 

How Thermal Fluid Heating Works 

oil separation heater elementsThermal fluid heaters work by constantly circulating heat transfer fluids in a closed loop. This continuous flow provides a heat source that operators can access whenever necessary. 

Operators of thermal fluid heating systems can vary fluid temperature through control loops. Generally, the thermal fluid must remain in liquid form to stay effective. However, some systems support vapour phases for applications where latent heat is better than simple heat. 

The target object never directly interacts with the fluid heating system. As a result, operators have plenty of control regarding how they heat the object, especially when timing is of the essence. 

Types of fluids used in thermal fluid heaters

Operators can use numerous heat transfer fluids in a thermal system. However, they must carefully choose the fluid for their application. That’s because different fluids behave differently based on their chemical composition. Operators use four key factors to determine what fluid is ideal for the system. They are:

  • Temperature:  Some fluids have higher or lower operating temperatures, affecting how effectively they apply heat to a target object. 
  • Pumpability:  Fluids can have different viscosities, influencing how easily they can be pumped. 
  • Pressure:  Some fluids react more or less favorably under specific pressure settings. 
  • Stability:  Certain fluids break down faster than others when subject to high temperatures, reducing their heating efficacy. 

Other factors may come into consideration. But these four — namely, temperature — are the main ones determining whether a fluid is suitable for the process. Some of these fluids are used in a variety of industrial applications. 

Commonly used heat transfer fluids in thermal fluid

  • Water:  The most cost-effective heat transfer fluid is water. However, it has a limited temperature range making it ineffective for many applications. 
  • Oils:  Regular and synthetic oils comprise this category and support a broader spectrum of applications than water. That’s mainly due to their wider temperature range (as low as -80℃ and as high as 400℃). 
  • Glycol-based fluids: Liquids made with ethylene glycol or propylene glycol can operate between -50℃ and 175℃. 
  • Molten salts:  Compounds such as fluoride and chloride salts in molten form can make effective transfer fluids. They operate at extremely high temperatures, ranging from 285℃ to 565℃ and have low corrosivity.  

The most effective fluids skew toward working within a wide temperature range. Some applications may allow for more than one type of heat transfer fluid. 

Pros of thermal fluid heating

Thermal fluid heating is a preferred method of heating for many reasons. It provides many advantages compared to other types of heating and can have some distinct benefits for your applications. Generally, thermal fluid heating systems are more efficient and stable than traditional boiler heaters. 

Advantages of thermal fluid heaters 

  • Sustains high temperatures at low pressures.  Thermal fluid heating systems can achieve high temperatures at a fraction of the pressure traditional steam systems require. 
  • Easy to maintain.  A thermal fluid system only requires flashpoint tests and virtually nothing more. The circuitry and wiring in these systems are simple enough that they don’t need regular servicing. Also, thermal fluid heaters don’t require blowdowns, maintenance of steam traps or re-tubing like regular boilers do. 
  • No supervision required.  Most heating units and boilers need engineers on standby due to safety concerns. Thermal fluid heaters don’t need supervision due to their simplicity and the fact they’re often isolated from workers. 
  • Lower costs.  Compared to traditional boilers, thermal fluid heaters require far less maintenance and energy output, making them less costly to operate. 
  • Outdoor functionality.  Since thermal fluid heating systems generate indirect heat, plant managers can arrange to place them outdoors. Keeping the heater away from other plant facilities can improve safety. 


Wattco thermal fluid heating solutions

Thermal fluid heating systems can look different depending on the type of fluid used and the application at stake. Most of these systems use a combination of pipes, flanges, valves, pumps, and other equipment

Additionally, depending on the application, certain materials will work better than others. For example, we recommend steel piping if you’re using corrosive fluids. However, we will recommend the most suitable material for your particular operation and fluid selection. 

Regardless of your industry, the Wattco team is here to help you. We will help you select the right thermal heating equipment (including materials) and heat transfer fluids to support your process.