Chromalox Big Red Book

Technical

Technical Information Determining Pressure Drop - Air and Gas Heating

Graph G-227ADH — Pressure Drop Vs. Velocity ADH and ADHT Tubular Element Air Heaters

Graph G-112S3 — Pressure Drop Vs. Velocity Finstrip ® and CAB Air Heaters 1.0

2.0

Based on 1-5/8" spacing and 4.7 fins per linear inch

ADH or ADHT Mounted Crosswise in Duct

A D H T M = 9 .5 " A DH M =1 8. 37 5" A D H M =9. 5"

0.5

1.0 0.7 0.5

Air Flow

Triple Row Double Row Single Row

0.3

0.3

0.1 0.07 0.05

0.1 0.07 0.05

0.03

0.03 Pressure Drop — Inches of Water (Psi = Inches of Water x 0.0361)

0.01 0.007 0.005

Pressure Drop — Inches of Water (Psi = Inches of Water x 0.0361)

0.01

0 0

5 fps 10 fps 15 fps 20 fps 25 fps 30 fps 35 fps 300 fpm 600 fpm 900 fpm 1200 fpm 1500 fpm 1800 fpm 2100 fpm Air Velocity (Std. Air)

0.003

Graph G-189S1 — Pressure Drop Vs. Velocity Fintube ® Elements and Air Heaters Note — Contact factory for pressure drop calculations for ADH/ADHT air heaters mounted lengthwise in duct and ADHT heaters where M is greater than 9.5"

0.001

0 0

5 fps 10 fps 15 fps 20 fps 25 fps 30 fps 35 fps 300 fpm 600 fpm 900 fpm 1200 fpm 1500 fpm 1800 fpm 2100 fpm Air Velocity (Std. Air)

0.7 0.5

Finned Tubulars Mounted Crosswise in Duct

Graph G-227-2 — Pressure Drop Vs. Velocity TDH Tubular Element Air Heaters

S i x R o w s M =1 8 . 37 5"

0.3

T h r e e R o w s M =9 . 5 "

0.20

Air Flow

TDH Mounted Lengthwise in Duct Air Flow TDH-6 TDH-12 TDH-18 TDH-24 TDH Mounted Crosswise in Duct Air Flow

0.18

0.1 0.07 0.05

0.16

Lengthwise TDH-24 Lengthwise T DH-18

0.03

0.14

Pressure Drop — Inches of Water (Psi = Inches of Water x 0.0361)

Length wise TDH-12

0.12

0.01

0 0

5 fps 10 fps 15 fps 20 fps 25 fps 30 fps 35 fps

T h r e e R ows C r o s s w i s e A n y R a tin g

0.10

300 fpm 600 fpm 900 fpm 1200 fpm 1500 fpm 1800 fpm 2100 fpm Air Velocity (Std. Air) Note — Contact factory for pressure drop calculations for finned tubular element air heaters mounted lengthwise in duct. Graph ADHTB — ADH/ADHT Terminal Box Tempera- tures Field Wiring Selection Guide

0.08

0.06

Pressure Drop — Inches of Water (Psi = Inches of Water x 0.0361)

L engt hwis e TDH -6

600

0.04

500

0.02

400

0

ADH Air Heaters

300

0 0

5 fps 10 fps

15 fps 20 fps 25 fps 30 fps 35 fps

300 fpm 600 fpm 900 fpm 1200 fpm 1500 fpm 1800 fpm 2100 fpm Air Velocity (Std. Air)

ADHT Air Heaters

200 Approximate

100

Data only valid for ADH or ADHT air heaters installed in bottom or sides of duct

Terminal Box Temperature (°F)

0

0

200

400

600

800

1000

1200

TECHNICAL

Outlet Air Temperature (°F)

INFORMATION

I-21