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Difference between revisions of "Air Heaters"
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[[File:Air_heater2.jpg|thumb|right|Air heater]] | [[File:Air_heater2.jpg|thumb|right|Air heater]] | ||
A '''Air heater''' is an object that emits heat or causes another body to achieve a higher temperature. In a household or domestic setting, heaters are usually appliances whose purpose is to generate heating (i.e. warmth). Other types of heaters are Ovens and Furnaces. Heaters exists for all states of matter, including solids, liquids and gases and there are 3 types of heat transfer: Convection, Conduction and Radiation. | |||
==Working method== | |||
Air heaters work by radiating heat into the passing air/fluid. Unfiltered air may contain dirt, grease and water which will reduce heater life, especially for open coil air heaters. Important is an air flow over the air heating element for some time even after the heater is turned off. Use a time delay relay for this. If the temperature sensor is far downstream from the air heating element, place an over-temperature sensor close to the air heater itself. We recommend the use of a flow switch in the airstream to avoid any overheating of the system in case airflow is insufficient. | |||
Air can be heated with open-coil heaters, tubular heaters, strip heaters and quartz heaters. The choice of one over the other depends mainly on volume, pressure and air velocity. To increase heater life, use a phase-angle fired or zero-cross fired ( SCR ) power control. | Air can be heated with open-coil heaters, tubular heaters, strip heaters and quartz heaters. The choice of one over the other depends mainly on volume, pressure and air velocity. To increase heater life, use a phase-angle fired or zero-cross fired ( SCR ) power control. | ||
==Calculate== | |||
To calculate the approximate power requirement in kW: multiply the standard cubic feet per minute (scfm) by the temperature difference and divide by 3000. [kW = (SCFM x Delta T)/3000](example: to heat 100 scfm 100 degF you'll need 3.3 kW) | To calculate the approximate power requirement in kW: multiply the standard cubic feet per minute (scfm) by the temperature difference and divide by 3000. [kW = (SCFM x Delta T)/3000](example: to heat 100 scfm 100 degF you'll need 3.3 kW) | ||
==Important factors to consider== | |||
*temperature sensor for air heater | |||
*temperature controller for air heater | |||
*electrical power switching for air heater | |||
==Heaters== | |||
* [[Tubular Heaters]] | |||
* [[Coil Heaters]] | |||
* [[Strip Heaters]] | |||
* [[Quartz Heaters]] | |||
* [[Ceramic Heaters]] | |||