How this calculator works
The sensible-heat balance assumes one phase and constant specific heat. Plane conduction assumes a uniform layer in steady one-dimensional flow; convection uses a supplied film coefficient. Net radiation assumes a small diffuse grey object surrounded by a large isothermal enclosure with view factor one. Radiation temperatures are absolute. A positive rate means energy leaves the named source for the sink; reversed temperature ordering reverses the sign.
Formula
Q = mc(Tf - Ti); Pcond = kA(Th - Tc)/L; Qcond = Pcond t; Pconv = hA(Ts - Tb); Prad = epsilon sigma A(Ts^4 - Tsur^4).
Worked example
A 1 kg sample with c = 1000 J/(kg K) heated by 10 K absorbs 10000 J. A 0.1 m layer with k = 0.5 W/(m K), A = 2 m² and a 20 K difference conducts 200 W, or 12000 J in 60 s.
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Frequently asked questions
What is the difference between heat and heat rate?
Heat is energy in joules; heat rate is power in watts, or joules per second.
Can I add the mechanisms?
They may act together, but use a complete thermal balance and compatible surface temperatures rather than simply adding unrelated estimates.
Can radiation use Celsius to the fourth power?
No. The input selector converts Celsius to kelvins before the fourth powers are evaluated.