Electric Duct Heater Pressure Drop

Thermolec electric duct heaters are designed for use in all forced air commercial and industrial hvac systems.

Electric duct heater pressure drop.

If airflow in the duct is expressed in fpm then a direct cross reference can be made by comparing the temperature of the air as it enters the duct heater to the kw rating on the table at the rated air velocity. To properly match a duct heater to an application the wattage air velocity and element watt density must be determined. This can result in reduced fan 2 motor horsepower and makes it possible to retrofit open coil heaters into existing systems without changing the fan motor. Static pressure drop through an open coil heater is quite low and in most cases can be ignored when calculating system pressure drop.

Calculating pressure drop through a heater the chart shown below is the approximate pressure drop through a heater based on the velocity of the. For tubular duct heaters the limitation is usually about 13kw per square foot. Electric heater thyrister control panels. Maximum discharge air.

Sheath temperature and air velocity graph. The pressure drop across a finned tubular heater is greater than across an open coil. Their applications vary from a partial or auxiliary nature to being the major or principal heat source in a building. Low pressure drop because of the high percentage of open space across the heater open coils have very low pressure drop as compared to finned tubular heaters.

Inches h20 kw ft 2 x velocity in fpm 2 760 500 8. Formulas and graphs that will aid in your design include. Since an electric duct heater has a constant btu h output as long as the heater is energized a mini mum air velocity must be maintained through the heater. Commercial industrial applications commercial industrial retail education residential.

When we trap the heat excess humidity and. X 3 ft total watts equal 20 000 watts per sq. Same concentration of wattage as an open coil heater. However if pressure plates must be added to an open coil the pressure drop over the open coil far exceeds the drop over a.

Stab in electric heaters. Element watt density vs. This can result in reduced fan motor horsepower and makes it possible to retrofit open coil heaters into existing systems without changing the fan motor. Duct size equal 2 ft.

20 000 3333 6 c. Wattage calculation formulas and table. Low pressure drop because of the high percentage of open space across the heater open coils have very low pressure drop as compared to finned tubular heaters. Proper air flow will prevent over temperature.