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Heaters 101: How a Heater Works

20 November 2020 Bookmark and Share


Heaters, in one form or another, are all around us. Even those who live in warmer climates drive cars with heaters in them. Although commonly used for personal applications, heaters can be a critical element for many commercial applications, too, such as drying concrete and/or keeping employees warm at a construction site. A commercial heater can prove to be an incredibly valuable asset for a business, so it’s worth knowing how some of them work to determine which kind might be the best for your needs.


Mobile Air & Power Rentals offers many different types of heaters, but today we’ll discuss three of our most popular variations, which are direct fired, indirect fired, and electric. They are all unique in fundamental ways, but every one of our heaters has two essential elements: a component that creates heat, and a fan to blow air over that component. A lot of complex design goes into each individual heater, but their basic function is quite simple to understand.


When it comes to efficiency, a direct fired heater is usually the best option available. Inside each heater is a burner, or a component that dispenses fuel to be burned during the unit’s operation. A fan then blows air through the burner, resulting in a warm stream of air circulating through a heated space. While the direct contact between the flame and the processed air makes direct fired heaters extremely efficient, it also means that combustion byproducts will enter the heated space. In applications where clean air isn’t a necessity, direct fired heaters are a great option for efficient and reliable heat.


Indirect fired heaters are often a suitable alternative for environments that require the air to remain clean. They function similarly to a direct fired heater, in the sense that they also have a burner and a fan. The difference, however, is that the burner is contained within a heat exchanger. The heat exchanger is a chamber that’s sealed off from all of the processed air, where an additional exhaust chute or duct vents any combustion byproducts out of the heat exchanger. This keeps combustion byproducts separate from the processed air, resulting in a heated space with clean air. Since the heat exchanger must absorb the heat and then transfer it to air being passed through the unit, and since the combustion byproducts have their own small amount of thermal energy, it is less efficient than a direct fired unit. When clean air is a necessity, however, indirect fired heaters are an excellent choice.


While direct and indirect fired heaters are nearly alike, electric heaters are a class of their own. These units still have a fan, but a heating element is used in place of a burner. Much like how a light bulb creates heat and light when turned on, electricity passing through the resistive element will generate heat. The heat is transferred by air passing through the element, in turn warming up the heated space. Electrical heaters are typically simpler and more portable than fired heaters. If fuel isn’t readily available, an electrical heater is likely the best choice for a business.


Although there are many types of heaters that can vary dramatically in how they work, these are some of MAPR’s best and most popular varieties. In our next installment, we’ll discuss make-up air and why we use it in some of our heat solutions.

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