Thermal resistances adding formula

[LinearMan]

Homework Statement

Prove a rule for adding of Thermal resistances
for: A)R1 and R2 in Series
B)R1 and R2 in Parallel

Homework Equations

The Attempt at a Solution

According to the book the result should be :
A) R = R1 + R2
B) 1/R = 1/R1 + 1/R2

So i thought we can get some ideas from the theory of Electrical resistance because these formulas are similar for example here: http://www.grc.nasa.gov/WWW/k-12/airplane/ohmrser.html .
However, I don't know how to start (in Thermodynamics there is no Electric current etc., so we can hardly use Ohm´s formula like in previous case).
Thanks for help

 

[Sunil Simha]

The thermodynamic analog of current is the Heat Current defined as the rate of flow of heat through the material and the analog of voltage is temperature difference

 

[LinearMan]

OK, thank you.

 

[LinearMan]

I get it

 

[CWatters]

in Thermodynamics there is no Electric current etc., so we can hardly use Ohm´s formula like in previous case

Not exactly but...

heat flow = ΔT/Thermal Resistance

which is similar to

Current = ΔV/Electrical Resistance

I'll let you work out the units.