HEAT TRANSFER


Electric thermal fluid heaters are often more compact than fired alternatives


Below: A separate unit houses the controls, power section and safety circuits


THE RISE OF ELECTRIC THERMAL FLUID HEATERS


Etienne Fourie, Technical Sales Manager, Babcock Wanson, discusses the important differences between electric thermal fluid heaters and their fired counterparts


thermal fluid heaters have never been so popular across a wide range of industries and processes, whether replacing traditional steam systems or for new production lines and sites.


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However, as energy efficient as they are, the majority of thermal fluid heaters in the UK remain gas or oil fired. Electric thermal fluid heaters are readily available and are tried and tested; Babcock Wanson has been building them since the 1970s. Whilst their uptake in the UK has been historically low due to the


comparative cost of electricity over gas, the push to decarbonise is seeing a rapid rise in the sales of electric thermal fluid heaters. If you are considering investing in electric thermal fluid heaters as part of your decarbonisation


strategy, there are some important differences between these and their fired counterparts that need to be factored in. Design and construction: an electric thermal fluid heater has a fundamentally different design from fired models. Unlike fired units, electrical units have no need for a combustion chamber or combustion controls. Instead, electric heating elements deliver the necessary heat. The design is more focused on the heat flux from these elements and ensuring a


16 MAY 2025 | PROCESS & CONTROL


thermal shock of the system, and improving turndown. Whilst electric thermal fluid heaters themselves are often more compact than fired heaters, they have a second, separate unit which houses the controls, power section and safety circuits, which is large. This latter unit varies significantly depending on the manufacturer. Step control on the elements


ith their energy efficiency, versatility, ease of use and ability to provide precise temperature control,


controlled high velocity of thermal fluid over the elements to avoid overheating. There are essentially two key designs to choose between: those with a single element and those with multiple. The former are the more costly and require more space to allow for maintenance, whilst the latter simplifies the design, installation and maintenance of the heater. Babcock Wanson electric thermal fluid heaters are based on multiple 50 or 60kW elements mounted in individual tubes which also enable better control of the flow path, reducing the risk of degradation of the thermal fluid and


is the most frequently used method of control, but this brings the risk of over heating the thermal fluid, and thermal shock. At Babcock Wanson, we instead use thermistor controls to reduce this risk and to provide a 50:1 turndown on the units. Installation: Having no direct emissions also means no need for flues and no discharge of flue gasses, which simplifies the positioning and installation of the units. There is also no need for fuel supply pipework and infrastructure, grid supply or the safety implications of having combustible materials on site.


Maintenance: With fired heaters, your maintenance team need to be qualified to work on fuel systems and combustion controls, whereas for the electrical units they need qualifications on 3-phase electrical systems.


Electric thermal fluid heaters overall have less maintenance requirements as there is no fuel pipework, gas boosters, gas metering stations etc to be maintained. Safety: With electric thermal fluid heating systems, combustible fuels and their associated risks are removed, making for an even safer system. Impediments: Electric thermal fluid heaters put a lot of ticks in a lot of boxes for sure, which does beg the obvious question: why isn’t everyone moving over to them? Electricity costs remain the main stumbling block, but even if costs became comparable with gas, we don’t have the infrastructure in place for a mass migration to electric. In the Net Zero Emissions by 2050 Scenario (NZE Scenario), the electrification of heating applications will see a 45% rise in electricity consumption in light industry by 2030 and 38% rise in hard to abate industry. Even with the government’s plan to unblock the grid, speed up planning decisions and build more renewables, it seems wholly implausible that the grid will be able to generate this amount of energy by 2030, or have the connectivity in place to transmit it nationwide. There’s no doubt that electric


thermal fluid heater sales will continue their upwards trajectory, but the reality is that in the UK, for the immediate future, most of these installations will be for small to medium sized units.


Babcock Wanson www.babcock-wanson.com


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