Thermal heaters, or thermal fluid heaters, are used for heating a liquid-phase heat transfer medium via an indirect heating method and circulating it to one or more heat energy users within a closed loop system. Thermal oil, water, and glycol are three of the most commonly used mediums.
High-efficiency heating systems like thermal heaters offer a range of benefits. For instance, when using synthetic oils, thermal mediums allow for high-temperature operations (up to 800 °F) while maintaining low pressures. Also, frost, corrosion, and scale formation can all be easily avoided when using oil-based heat transfer media.
Thermal heating systems can be used in a wide range of applications, including metal fabrication, printing presses, auto manufacturing, and food processing plants. Gas-fired thermal heaters, oil-fired thermal heaters, and waste fuel-fired heaters are three of the most common types of thermal heating systems.
Gas-Fired Thermal Heaters
In gas-fired thermal heaters, natural gas is used as fuel. A burner transfers heat energy to a thermal oil in a tube or coils, and circulation is achieved by force. This process transports the heat to the thermal equipment being used. Then, the oil returns to the thermal oil heater to continue the high-efficiency heating process.
This heating style allows for many customization options, enabling almost any furnace burner style to be used in single- or multi-burner configurations. Also, gas-fired thermal heaters do not require much pressure to perform.
Oil-Fired Thermal Heaters
An oil-fired thermal heater, or thermal oil boiler, fires through a helical coil to generate energy from combustion products; radiation and convection are used to heat the coil. The coil then heats thermal oil, which gets pumped through the boiler.
Used for applications such as crude oil heating and indirect steam generators, oil-fired thermal heaters outperform water boilers in that operations and maintenance are less costly. And, since less pressure is required for heating, these systems are also safer. Other advantages include the elimination of the corrosion, lime deposits, and scale formation usually present in heated water and steam systems. Also, there is no need for draining steam traps or makeup water.
These heaters are often used for jacketed vessel heating, natural gas heating, in-line gas heating, and heated molds or dies.
Waste Fuel-Fired Heaters
Another high-efficiency heater, waste fuel-fired heaters run on waste, producing eco-friendly heat. Some even call this “free heat,” since applications using this type of heater are run on old, unusable oil. The waste oil itself is synthetic or petroleum-based oil that no longer serves its original purpose because it is impure, broken down, or has been exposed to the elements for extended periods of time.
In waste fuel-fired heaters, the oil fills a burner’s tank and is pulled through a filter and pumped to the burner. Once preheated to the optimal temperature, it is atomized and sprayed into a blast tube, then ignited by a high-voltage starter. Hot air is then transferred to cool water or air passing through the other side of the exchanger, which is expelled into the application.
With the proper filtration processes and waste fuel oil, waste fuel-fired heaters can provide reliable solutions for heating applications such as office heating and residential furnaces.
Thermal heating systems offer significant advantages over other types of heating solutions, ensuring optimal safety, cost efficiency, and reliability. Though steam systems used to be the go-to options thanks to their high availability and environmental friendliness, thermal heating requires much less pressure and allows for lower pumping costs. And with fewer components involved, thermal heating eliminates the risk of corrosion, scaling, and fouling, making this a prevalent method in process industries. Thermal oils can also be used in applications running at temperatures below 32 °F.