Heat Transfer Analysis

Heat transfer analysis can help to slow fluid degradation

Because synthetic and mineral thermal fluids operate at a high temperature for long periods, they naturally degrade over time. You cannot see the heat transfer fluid once it enters the system, so thermal fluid analysis is the only way to monitor fluid condition and ensure that maintenance is carried out when needed to prevent unnecessary degradation.

What is thermal fluid degradation?

Over time, the molecules in a thermal fluid will break down by a process called thermal cracking and oxidation, creating volatile light ends, and heavy ends and organic acids. As well as causing the thermal fluid to degrade, thermal cracking and oxidation also produces carbon molecules that stick to the pipes and system, which reduces efficiency.

Furthermore, organic acids which results from the oxidation process are both corrosive and help to accelerate the production of carbon and fouling. Light ends lower flash points and increase risk of fire.

If a fluid and system are left unattended the fluid will potentially thermally degrade at a much faster rate. You may only notice this once it begins to impact production.

Once this occurs you must test and analyse a sample of the fluid and respond to the data with the appropriate intervention. If necessary, you must shut down production, drain, clean and flush the system and then purchase new fluid, which is a costly and time-consuming process.

Why should I monitor fluid condition?

The Dangerous Substances and Explosive Atmospheres Regulations (DSEAR) of 2002 and the Explosive Atmosphere Directive (ATEX 137) set the minimum requirements for protection against risks from fire, explosions and similar events arising from dangerous substances used or present in the workplace.

Thermal fluid analysis is an important process in order to adhere to these guidelines. Understanding fluid condition will assure you that the system is working efficiently with a stable thermal fluid that is not putting the workforce at risk.

Abiding to DSEAR guidelines also helps companies identify early warnings regarding process problems, helps maintain a safe and efficient working environment and save costs. In environments where the risks are so high, no expense should be spared to ensure legislation is respected and thorough efforts are made to keep employees and premises safe.

How can I slow heat transfer fluid degradation?

The best way to slow fluid degradation is to understand what is happening inside the system. All fluids degrade overtime but it does not go from being fit for use to needing replacement overnight.

There is a grey area where fluids can be managed against what specialists call “the degradation curve”. Only as the fluid approaches the end of its practical working life, there is a gradual curve which eventually drops off very sharply. This sudden change in the quality of thermal fluids is one of the reasons why regular and preventative maintenance is so important.

You should regularly collect representative fluid samples to understand how the system and the HTF performs.

You should collect a closed sample of the fluid while the system is hot and circulating. This will give you an accurate representation of the condition of the fluid inside the system, allowing you to more accurately anticipate what could happen in the near future.

We encourage you to take a representative sample every three months to closely monitor fluid condition. This is the best way to adhere to regulations and operate a safe and efficient system and reduce maintenance costs.

What does heat transfer analysis involve?

Global Heat Transfer provides a sampling and heat transfer analysis service in line with legislative and insurance requirements. Our thermal fluid specialists will visit the site to safely collect a representative hot circulating, closed fluid sample.

The heat transfer fluid sample will then be analysed in a fully accredited laboratory that carries out eleven approved thermal fluid tests. You will receive a fluid report detailing our findings and recommendations based on a variety of factors. Experts will interpret data and give advice on maintaining thermal fluid efficiency based on the individual history of your system and fluid.

In your report you also receive a compilation of system trends and service history to get an accurate representation of system and fluid performance.

What are the benefits of regularly monitoring thermal fluid condition?

Regularly monitoring thermal fluid will extend the life of your fluid, slow degradation and reduce carbon deposition and fouling that will damage your heat transfer system and reducing risk by managing flash points as they change. Monitoring thermal fluid can also help you to optimise the system, reducing energy costs, improving health and safety and reducing downtime.

Regular sampling can also act as an early warning system, allowing you to anticipate the end of the fluid’s life. At this point, you can plan effectively for system and fluid management interventions with the help of the Thermocare maintenance plan.

Our Thermocare Proactive Maintenance plans include regular services, including our thermal fluid analysis service. You can choose either the essential, optimum or ultimate plan based on your needs.

How can I get advice from thermal fluid specialists?

Global Heat Transfer can help you find the right services that will help you improve heat transfer system efficiency. Speak to one of our engineers by calling +44 (0)1785 760 555 or visit our contact page.


Our Thermal Fluid Testing & Analysis service includes:

  • Site visits from our experienced engineers to safely collect representative hot, closed samples in line with recommendations from the Health & Safety Executive (HSE) and DSEAR / ATEX regulations and decanted under lab conditions
  • A suite of 11 approved thermal fluid tests performed by a fully accredited independent laboratory
  • Expert analysis based upon the individual case history of your system
  • Expert interpretation of the data and advice on maintaining maximum system and thermal fluid efficiency
  • Expert recommendations to ensure you comply with health and safety legislation
  • Full report of our findings and recommendations where necessary
  • A compilation of system trends and service history in order to pre-define thermal fluid performance

We have unparalleled experience in interpreting technical data and advising our customers on the best action for managing the condition of their thermal fluid. That’s why we’re the market leader.

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The main benefits to monitoring the condition of your thermal fluid are:

  • Operate a safe business knowing your thermal fluid is analysed in line with DSEAR / ATEX requirements for the duration of the plan
  • Reduce carbon deposition and fouling which will damage your system. Average Capital Expenditure costs for replacement parts are £15,000* for a heater coil and £40,000* for a new heater
  • Reduce downtime Typical manufacturing businesses lose over £30,000** per hour if output is not maintained
  • Reduce Costs Deterioration in your thermal fluid does not necessarily warrant instant replacement. There are a number of measures we can take to extend fluid life before it is classified as condemned, including filtration, light ends removal and thermal fluiddilution.
  • Lower your environmental impact by producing less waste
  • Reduce the risk of a health and safety breach by proactively monitoring and managing the condition your thermal fluid
  • Comply with insurance requirements to monitor the condition of your thermal fluid
  • Enjoy energy savings – carbon in your system will ensure you spend more on energy as carbon can’t be heated. Degraded oil in your system will draw more energy as your pumps work harder.
  • Regularly assess the extent of system wear by taking regular thermal fluid samples
  • Regular sampling serves as an early warning system for future events and enables you (or us in the case of Thermocare™ Maintenance plans) to plan effectively for system and fluid management interventions
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* Average Capital Expenditure costs for replacement parts are £15,000* for a heater coil and £40,000* for a new heater based on 10,000 litres. This is in addition to the cost of draining the system, flushing the system and refilling it with a new charge of thermal fluid suitable for your application.

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