Steam, water and thermal oil coils

A steam coil, thermal oil coil or air heater is a type of heat exchanger whose purpose is to raise the temperature of the air used, among others, in equipment such as burners or dryers.

Among the thermal fluids to be used, the most common would be saturated steam or superheated water, but thermal oil also stands out, taking advantage of its good capacity to transfer heat efficiently.

How does a steam, water or thermal oil battery work?

A steam, hot water or thermal oil coil is a heat exchanger designed to heat air by means of a thermal fluid, which can be steam, superheated water or thermal oil. These coils are placed in systems where the air temperature needs to be raised, such as furnaces, industrial dryers or air handling units. By transferring the heat from the heat transfer fluid to the ambient air, the energy efficiency of the overall system is optimized, reducing the need for additional energy and improving the efficiency of the thermal processes.

Operation of a steam, water or thermal oil battery:

Heat transfer fluid inlet: The heat transfer fluid (steam, water or oil) enters the coil through a manifold and is distributed through the internal tubes of the heat exchanger.
Heat transfer: The cold air enters through the outside of the tubes, which can be either finned or smooth. In this way the heat is transferred to the air without the fluids mixing, raising their temperature in a controlled manner.
Hot air outlet: The already heated air is directed to the industrial processes that require it, such as dryers, furnaces or burners, ensuring a uniform and stable thermal supply.
Reduced emissions and energy savings: By using thermal fluids that are already available in the plant (such as boiler steam or recirculated thermal oil), the system’s energy is better utilized, reducing fuel consumption, pollutant emissions and operating costs.

It consists of:

Thermal fluid circuit: It consists of a set of tubes, which can be smooth or have fins. The system is complemented by two collectors located at the sides: one is in charge of receiving and distributing the thermal fluid at the inlet, and the other collects the fluid at the outlet.
Air circuit: Circulates outside the tubes, perpendicular to the thermal fluid circuit. The air can circulate thanks to the action of a blower that can be either forced draft or induced draft.

What types of batteries are there?

Aitesa designs the following types of batteries:
- Saturated air-steam coil
In this case the thermal fluid is saturated steam. In order to heat the air, all the steam introduced must be condensed, releasing a large amount of energy during this phase change, which comes from the latent heat, transferring it to the water. Due to the peculiarity of condensation, these coils must be designed in total flow, i.e. uniformly feed all the tubes at the same time, and it is important to ensure the correct condensation and movement of the fluid to avoid cold areas or vapor return points. Its efficiency is due to the high calorific value of the phase change.
- Overheated air-water coil
These coils use superheated water to heat the air. Since it is liquid water, the coil configuration allows the tubes to be fed by means of different flow configurations: single Flow, double Flow, etc. In this particular case, the key is to make the water flow at a velocity between 1-3 m/s, resulting in an optimal exchange, avoiding problems due to high pressure drop or erosion.
- Thermal air-oil coil
These batteries use thermal oil as the heat transfer fluid, which allows higher temperatures to be reached than with water or steam. However, their design presents several particular challenges. Since it is thermal oil, which has a high density and viscosity, a higher velocity through the tubes is necessary, which is especially important since it is an excellent heat transmitter, which, in the case of flowing too slowly through the tubes, can burn them. This coil also allows single Flow or double Flow configurations, adjusting for optimum velocity.

It should be noted that, in the three types of batteries, in the case of having fins on the outside of the tubes, these would be aluminum fins, since the fluid circulating through them is air, which can be considered clean and non-corrosive.

Not sure which one you need? Our team of experts can analyze your process and recommend the best solution.

At AITESA we are experts in the design of steam batteries and thermal oil batteries.

Key benefits for your industry

Thermal energy utilization

Coils allow heat to be transferred from thermal fluids to air in a controlled and efficient manner, allowing existing energy to be reused in the form of steam, hot water or thermal oil without the need to generate additional heat. This results in lower energy costs and improved overall plant efficiency.

Improved kiln and dryer performance

The air preheated by these coils reduces the subsequent thermal stress of furnaces or main equipment, speeding up production cycles and reducing fuel consumption in later stages of the process.

Safety and durability

Designed with materials resistant to pressure, temperature and corrosion of the heat transfer fluid, these batteries offer safe operation and long service life, even in demanding industrial environments.

Reduction of pollutant emissions

The energy efficiency achieved through these batteries also has a positive impact on the environment. By reducing the consumption of fossil fuels, emissions of greenhouse gases and other pollutants are reduced. This contributes to a company’s lower carbon footprint and improves its environmental profile, which is increasingly valued in the marketplace and can facilitate compliance with environmental regulations.

Adaptation to customer needs.

We adapt the batteries to different environments and needs. They can be configured according to the specific requirements of each process, such as temperature. They are also compatible with existing equipment, which facilitates their integration without the need for major changes to the existing system.

Steam battery

Industrial sectors where steam, water or thermal oil coils are used

Food industry : In this sector, thermal coils are used to heat air in dryers, ovens, cooking tunnels and pasteurization or dehydration systems. Precise control of air temperature is essential to ensure the quality, safety and hygiene of the final product. They are also used in CIP (Cleaning In Place) systems that require hot air for drying after cleaning.
Paper and textile industry: In both paper manufacturing and textile processing, coils are used in drying processes, especially in drying cylinders or forced air dryers. They accelerate the evaporation of moisture without damaging the material, and are key to achieving a homogeneous end product with a good surface finish.
Chemical and pharmaceutical industries: In these industries, where rigorous thermal control is required, coils are used to heat air in reactors, drying cabins or clean room ventilation systems. The use of thermal oil in particular allows high temperatures to be reached in a stable manner. They are also used to maintain controlled atmospheric conditions in laboratories and sterile production areas.
Glass and ceramics industry Thermal: coils are used to preheat combustion or drying air, optimizing the energy efficiency of high-temperature furnaces. Preheating the air before it is introduced into the furnace reduces fuel consumption and improves control of the thermal process, which is essential to achieve good quality in glass and ceramics.

Do you need a customized solution for your industry? Contact us and we will design the ideal equipment for your process.

Key factors in choosing the right battery

Sizing and capacity

Heat absorbed
Space limitations
Adaptability to existing installations

Process conditions

Flow rate
Temperature
Pressure
Fluid velocity

Thermal fluid

If it is about:

Superheated water
Saturated steam
Thermal oil, and which one in particular you plan to use

Modular design and adaptability to existing installations

Integration without modifying the plant infrastructure.
Configuration to fit the available space.

Compliance with international regulations

ASME section VIII, EN 12952, EN 13445, API 661, ISO9001 certifications for maximum safety and quality.
Design adapted to specific requirements of the petrochemical, energy and manufacturing industries.

Compliance with customer specifications

Adaptation to specific customer requirements

Steam battery

At AITESA we study your case to offer you the best steam battery.

Why choose an AITESA battery?

More than 5000 projects in strategic sectors

40 years of experience designing batteries.
Adaptation to demanding environments such as refineries, petrochemical and industrial plants, where every degree of efficiency optimizes profitability.

Maximum efficiency and minimum emissions

Proven and optimized designs: our experience allows us to guarantee robust and safe solutions for every industry.
Reduced environmental impact with minimum heat loss and maximum thermal efficiency.
Reduced operating costs with advanced technology that maximizes thermal efficiency and minimizes energy waste.

Comprehensive technical support and maintenance

Maximum operational availability
Fast response and guaranteed supply to reduce downtime.
Solutions to problems

We not only design water heating coils, we create energy solutions that optimize your production, reduce costs and ensure regulatory compliance.

Success stories

Design and supply of steam coil banks and filtration system for a ceramic plant in Castellón

Carlota Galván | Success Stories - Steam Batteries | No Comments

We received a request to reduce the consumption of fossil fuels at the ceramics plant in Castellón. The proposal was to use the waste gases for preheating the combustion air…