Definition and general information
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Electric air heaters are used to heat air flowing through a duct. They are used in heating, ventilation, and air conditioning (HVAC) systems, as well as in air handling units (AHUs), to heat buildings, mechanical rooms, or offices.
They are also widely used in industrial processes (food processing, nuclear, chemical, etc.) for drying products, curing plastic parts, and baking paint in ovens or drying chambers.
The units operate on the principle of forced convection. Air blown into the duct by a motorized fan is heated upon contact with electric heating elements. The air can be heated in a single pass and then vented after use; this is referred to as open-loop operation. It can also be heated gradually through successive passes through the battery; this is referred to as closed-loop operation, which is the case in ovens and drying ovens.
They consist of several shielded electric heating elements (bare or finned), a housing or mounting plate made of steel or stainless steel, and a terminal box that protects the electrical connections and provides the power connection.
The unit can be equipped with a safety device—such as a thermostat, Pt100 sensor, or thermocouple—to measure the temperature either in the airflow or directly on the heating elements.
Available in box or panel-mounted designs, with round or rectangular cross-sections, these robust and weatherproof (up to IP66) units can be installed in demanding industrial environments such as the nuclear and maritime sectors, or in explosive atmospheres (gas) using ATEX - and IECEx-certified equipment.
- Rated power from 200 W to 3,000 kW.
- Single-phase voltage (110 to 230 V) or three-phase voltage (230 to 690 V).
- Air outlet temperature up to 600 °C
- Waterproofing of the electrical junction box (IP30 to IP66).
Implementation
Applications
Food industry
In a malting plant, air heating units are used to dry and kiln the grain. This process is crucial for halting the germination of barley and developing the aromas of the malt, which is used to make beer or whiskey.
Chemistry and pharmaceuticals
Air heating coils stabilize the temperature of the exhaust gases from DeNOx reactors to prevent the condensation of corrosive compounds and protect equipment. They provide precise heating up to 300°C, even in aggressive or ATEX environments.
Facilities management
Air heating terminal units are used downstream of air handling units (AHUs) or in HVAC systems to finely adjust the supply air temperature on a zone-by-zone basis. They provide localized thermal comfort, often with individual control.
Nuclear
In nuclear power plants, electric air heaters are used to maintain a constant temperature in the iodine traps, preventing condensation and ensuring maximum trapping efficiency.
Technical data
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Air heating coils consist of:
- Sheathed, bare, or finned electric heating elements make up the battery's heating components.
- The housing, made of steel or stainless steel, directs air over the heating elements and allows the unit to be connected to the customer's ductwork.
- The electrical connection is made via a connection protection box equipped with a cable gland. The terminal box can be mounted away from the housing when the process temperature is too high, in order to prevent the connections from overheating.
- Optionally, the battery can be equipped with a safety device mounted in a protective sleeve: a thermostat, a Pt100 sensor, or a thermocouple. Temperature measurement can be performed in the air stream or directly on the heating elements.
Further information
- Vulcanic offers ATEX and IECEx certified equipment for heating in explosive atmospheres (gas).
- In addition to the range of finished products featured in our online catalog, Vulcanic can design custom equipment, manufactured to order to meet your specific needs (power, voltage, dimensions, etc.).
Recommendations
Precautions for use
The terminal box must be kept clear and exposed to the open air to allow for natural cooling.
Under no circumstances should the battery be powered on without airflow.
Installation and connection
When installing the unit in a horizontal duct, it is recommended, whenever possible, to position the terminal box at the bottom or on the side to minimize overheating.
The counterboring of the mounting flanges should generally and preferably be done when the enclosure is installed on the customer’s duct.
Please refer to the instruction manual for all recommendations relating to the equipment.
