How do I choose a heat transfer fluid?
With so many heat transfer fluids (HTFs) on the market it can be difficult to select the right one for your application. You should select a heat transfer fluid based on its properties, such as thermal stability, temperature range and heat transfer efficiency. Finding the perfect fluid may seem daunting, so here are our tips on what you should consider when selecting a new heat transfer fluid.
Should I buy synthetic heat transfer fluid or mineral?
The chemical composition of a heat transfer fluid can be an organic or a synthetic compound. Chemical based heat transfer fluids can also be based on several chemicals, including silicone, terphenyl and alkylated aromatic compounds. Be aware that chemical composition impacts how suitable a fluid is for an application. So correctly matching the fluid to the system and application can help preserve fluid life in addition to a robust approach to condition monitoring and maintenance. You should consider purchasing synthetic heat transfer fluids because they have a lower propensity to form carbon than mineral based oils, offering better heat transfer efficiency and thermal stability. They are also more resistant to fouling, which means they tend to form less coke on the internal pipework and heater.
What qualities of a heat transfer fluid are important?
Thermal fluids must operate at the correct temperature for prolonged amounts of time, so you should pick a HTF that is stable at the temperature required for your application. You should look at both the highest and lowest operating temperatures when selecting a heat transfer fluid. The fluid must be able to work efficiently at the highest temperature but should also work at the lowest temperatures required during a system start up or if any of the system is outside of the facility.
State of matter
Heat transfer fluids can operate in liquid or vapour phase, depending on the application. Manufacturers should consider that changing the state of the fluid also changes its stability and operating temperatures. When purchasing a fluid, manufacturers should find out its minimum and maximum operating temperatures in both phases to know if it is the best choice.
Fluid viscosity can influence a manufacturer’s choice, as it impacts how easy it is to pump around the system and therefore how much energy is used. Synthetic fluids tend to have a lower viscosity than mineral-based fluids, so a manufacturer looking to reduce energy costs may prefer this option.
Are all thermal fluids safe?
In certain industries, including food and beverage, fluid choice may be influenced by HTF legislation. In food manufacturing, for example, you should opt for a food grade oil because it is certified non-toxic. Our Globaltherm FG fluid, for example, has outstanding thermal oxidation stability to meet the demands of food, beverage or pharmaceutical manufacturing. You should also consider the fluid’s base to ensure consumers are safe from toxicity. For example, in applications where there is a chance of ingesting the product, you should consider purchasing a propylene glycol-based fluid, as it has a lower toxicity than other HTFs.
How do I manage my fluid?
A heat transfer fluid will degrade over time because it has to operate at high temperatures for long periods of time. However, you may not be able to see degradation until it impacts production. You can slow degradation by implementing a continuous preventative maintenance programme and frequently monitor both the fluid and the system. You should take a hot, closed sample, to make sure it is representative. You should then analyse the sample to understand what is happening inside the system. We can help you create the right programme for your plant. We provide a condition based thermal fluid lifecycle maintenance programme, Thermocare, where our experts will work with you to improve accuracy when monitoring fluid, organise maintenance schedules and train staff at the facility.
How do I replace my fluid?
Once you have chosen your fluid, you should consider how you will introduce it to the system. You cannot simply remove one fluid and replace it with the next. Instead, you must drain, flush and refill the entire heat transfer system. This will increase the lifespan of the new fluid and keep the system running efficiently for longer. Globaltherm® C1 is specifically designed to remove harsh by-products of any heat transfer fluid, such as carbon deposits, volatile light ends or loose debris to ensure there are no contaminants that may compromise the new HTF.
How much should I spend?
Price will always be important when purchasing a new fluid for an application. The price of a fluid will depend on its properties, so the more specialised the fluid, the higher the price. You should choose a fluid that is cost efficient for the facility without compromising on the most important properties required for the application.
Why is fluid choice important?
Selecting the correct heat transfer fluid is important. Taking the time to carefully consider what fluid will work best for your application will help improve efficiency and increase the lifespan of the HTF and system.
Where can I get more advice?
Global Heat Transfer has over 25 years of experience in heat transfer fluid to help you invest in the correct thermal fluid for your application and facility. Have you got more questions about heat transfer fluid? Give us a call for more personalised advice on 01785 760 555 or you can visit our contact page for any enquiries.