Related Resources: heat transfer

### Radiant Heat Exchange Plates Different Sizes Equation and Calculator

Radiant heat exchange for two isothermal (constant temperature) parallel flat black plates of different sizes equation and calculator. ALL calculators require a Premium Membership

The heat flow (q) from the plate is calculated as:

q = 56.69 x 10-9 x VF(1-2) x L12 x (T14 - T24 )

Where 56.69 x 10-9 is the average Stefan-Bolzmann constant, L1is the area of the plate, T1 is the plate 1 temperature and T2 is the plate 2 temperature. The view factor VF(1-2) (also known as radiation shape factor, angle factor, and configuration factor) is defined as:

Length of plate 1 divided by the distance between the plates (L 1 / D) must be greater than 0.2 for this calculation. Where:

x = (C) x ( 1 +E )
y = (C) x ( 1 - E )
C = L1 / D
D = L2 / L1
W = Plate Width (W)
D = Spacing (m)
T1 = Plate 1 Temperature (K)
T2 = Plate 2 Temperature (K)
VF1-2 = View Factor
q = Radiated Heat Flow (W)

References

Rosenow, W. M., J. P. Hartnett, Y. I. Young, Handbook of Heat Transfer , 3rd Ed., McGraw-Hill Handbooks, New York, 1998. p. 7.3 - 7.19, 7.81.