The energy contained in diesel or fuel oil can be used for heating by burning the oil. Simple traditional auxiliary heaters consist only of an oil burner and a fan that is used to direct the heat from the oil burner to the desired spot in the form of hot airflow.
Airrex infrared heaters also include an oil burner, but instead of a naked flame, the heat is formed in a heat generator doubling as the exhaust system. From the heat generator, the heat is radiated to the surrounding atmosphere in the form of infrared waves. The heat radiation can be directed using the heat reflector structures in the heater.
Single- or multi-stage combustion diesel heaters
The forced airflow of traditional oil heaters with a burner and fan transfers all particles of the burned oil, including exhaust gases and unburned particles, directly through the heater into the heated space. Even with an efficient burner, the exhaust gas will contain small amounts of unburnt hydrocarbons and any contamination in the fuel. This will cause different kinds of smoke and odour emissions.
Basic tubular heaters simply use the fan to circulate the air in the heated space pass the oil burner. This means that unburnt hydrocarbons from the oil burner “supplement” any impurities already in the heated space air. The amount of unburnt hydrocarbons increases significantly if the diesel or fuel oil does not burn efficiently. This is usually the case during the starting or stopping of the heater or if there is a problem with the fuel supply to the burner.
Airrex infrared heaters burn the diesel or fuel oil very efficiently because, after the oil has been burned in the burner, practically all the remaining hydrocarbons are burned in the 3-stage exhaust system that doubles as the heat generator. In practice, the exhaust is left with only harmless carbon dioxide and water without any unburnt hydrocarbons causing unpleasant odours and/or health hazards. Airrex auxiliary heaters utilise practically all the energy contained in the fuel, meaning that they are highly efficient and consume very little fuel.
Exposed or protected oil burner?
Basic fan-equipped diesel and fuel oil heaters have their oil burners in direct contact with the outside air, exposing them to any impurities and humidity in the air. This can result in corrosion or dirt build-up in the burner structures, decreasing the performance and reliability of the burner.
If you use a fan-equipped auxiliary heater with an oil burner as the heat source, you must always make sure that the air going inside the heater does not contain any combustible material, such as dust, straws of hay or any combustible material that can be carried by the airflow. Another thing to remember when using this kind of a heater is that you also must consider the fire hazard caused by the hot air coming from the heater and any smouldering particles carried in it.
In Airrex infrared heaters, the oil burner is enclosed inside the device and has its own separate air intake channel. All air coming to the burner is burnt, and the resulting exhaust gases are directed to a long exhaust system that doubles as the heat generator. The flame of the burner is not in contact with the surrounding space, and exhaust gases and any sparks cool down and die out harmlessly in the exhaust system. The long exhaust system also protects the burner against damages due to any impurities and humidity in the air.
Difference between heating by airflow and heating by radiation
In case of a traditional oil burner, the hot naked flame heats the air directed past it by the fan. This means that the air in front of the auxiliary heater may be very hot. The heating effect becomes more even when the hot air mixes with ambient air. The heating effect of the heated air circulated by the fan can only be felt in places where the air can reach. In a large space with obstacles or structures blocking the airflow, there will be “nooks and crannies” where the heat cannot get.
Heat energy radiated by an infrared heater does not heat the air but the objects with which it comes in contact. Therefore, you can be close to the heater without feeling uncomfortably hot. Heat radiation spreads evenly in the space, literally warming up the objects in its path from the inside out. Once the objects and structures in the heated space warm-up, they also warm up the space evenly.
Do you want to circulate dust and air contaminants?
Fan-boosted air circulation always circulates contaminants, dust and other impurities in the space as well. This spreads air contaminants everywhere, including people’s skin and lungs and from there further in the body.
Heat radiation from an infrared heater does not cause any superfluous air movement that would cause dust or any contaminants in the heated space to migrate to the workspaces or supplies or in the bodies of people there.
Humming fan and buzzing burner – or not?
The humming sound of an efficient oil burner is familiar to all who have been around one. Traditional auxiliary heaters only have sound damping structures on the sides of the burner. And to ensure safe heater operation, the heated air must be made to move efficiently. This requires a fan that inevitably produces noise. Today, some high-end traditional auxiliary diesel heaters already have reasonably silent fans.
In case of the fully enclosed Airrex infrared heaters, the air to the oil burner is conveyed via a separate sound dampening channel. The exhaust system located downstream the burner utilises any energy left from the burned oil and also dampens the “exhaust noise” down to a very moderate level. Airrex infrared heater’s noise level is 48 dB, corresponding with that of a quiet speaking voice.
Burner requires electricity – a fan easily doubles the need for power
Traditional auxiliary oil heaters have some components that require electric power: fuel pump, oil burner with the associated control electronics and the fan that circulates air past the burner. The more powerful the burner, the more powerful a fan is required.
Airrex infrared heaters do not have a fan, so they require significantly less electric power than traditional auxiliary diesel heaters. This is why it is safe to also power them from an inverter connected to a vehicle’s electrical system.
Programmable auxiliary heater
Basic auxiliary heaters are simply filled up with fuel, connected to a power supply and switched on. Better equipped models are thermostat-controlled. High-end models have flame detectors and safety systems that switch the equipment off in case of any problems.
Airrex infrared heaters also include a versatile timing function as standard, allowing the heater to be programmed to switch on and off at precise times and to run for set periods.