This page calculates the isothermal temperature a rectangular volume embedded in a semi-infinite medium with an applied isothermal temperature.

The rectangular volume temperature *T _{b}* is calculated as:

T_{b} = T_{i} + q / (k x sf)

Where *T _{i}* is the isothermal temperature
applied to the medium surrounding the rectangular volume,

The rectangular volume shape factor is calculated as:

sf = 1.685 L [ log ( 1 + ( d / W ) ) ]^{-0.59} x ( d
/ H)^{-0.078}

Where *W* is the rectangular volume width, *L* is the
rectangular volume length, *H*
is the rectangular volume height, and *d* is the rectangular volume depth.

**References**

Holman, J.P., *Heat Transfer*, 7th ed., McGraw Hill Book Company, New York, 1990. p 74 - 83