A-102-1 Electric Duct Heater Brochure - Brasch

1300Minimum Air VelocityOpen Coil Elements1300Minimum Air VelocityFinned Tubular Elements*MINIMUM AIR VELOCITY (fpm)12001100100090080070060050082° - 100°F INLET AIR TEMPERATURE(HEAT PUMP APPLICATIONS ONLY)81°F MAXIMUM INLET AIR TEMPERATURE**MINIMUM AIR VELOCITY (fpm)120011001000900800700600500100°F-82°INLET AIR TEMPERATURE81°F(HEA PUMP APPLICATIONS ONLY)MAXIMUM INLET AIR TEMPERATURE*400400300300200200100———— UL100———— UL02 4 6 8 10 12 14 16 18 20 22 24 26 28 302 4 6 8 10 12 14 16 18 20 22 24 26 28 30HEATER FACE AREA (KW/FT 2 )HEATER FACE AREA (KW/FT 2 )*Maximum allowed watt density: 28.9 KW/FT 2 ) *Maximum allowed watt density: 17.0 KW/FT 2 )Face Area =KW/Ft 2 =.35(H-2 1 /2") (W- 3 /4")144KWFace Area0Example:25 KW UL Heater, Inlet 75° F12" H x 24" W, Open Coil ElementsFace Area = (12-21 /2") (24- 3 /4") = 1.53 Ft214425KW/Ft 2 == 16.31.5316.3 KW/Ft 2 = 700 fpmPressure Drop Through Heater (inches water)*PRESSURE DROP (inches water).30.25.20.15.10FINNED TUBULAR -5 COLUMNSOPEN COIL - 8" DEPTH OF COIL.050 500 1000 1500 2000VELOCITY (fpm)*This is an estimate ony and will vary with the specific construction of each heater. Calculations for specific heaters can be run on a computer program but are still rough approximatoions. Actual pressure drops can only be found by performingpressure drop tests on the actual duct heater after manufacture.18 BRASCH MANUFACTURING