Rick Karlquist wrote: > Bruce Griffiths wrote: > >> Mark Sims wrote: >> >>> Remember that heat flow is proportional to the FOURTH power of the >>> temperature difference. Insulation is generally a linear function. The >>> combination makes thermal stabilization over even small ambient >>> temperature ranges rather problematic. >>> >>> >>> >>> >> Nonsense. >> The radiative transfer between 2 bodies at different temperatures is >> proportional to the difference between the 4th powers of their absolute >> temperatures. >> > > And this quantity is approximately equal to the THIRD power of > the temperature difference for small temperature differences. > (A simple calculus problem!) > > Rick Karlquist N6RK > > The Taylor series expansion gives:
(T+h)^4 - T^4 = 4*h*(T^3) + 6*(h^2)*(T^2) + 4*(h^3)*T + h^4 The largest term of which is 4*h*T^3 for small h, and large T(absolute temperature). where ^ denotes the power of and * denotes multiplication. That is for small temperature difference the radiative heat transfer is proportional to the PRODUCT of the temperature difference and the THIRD power of the absolute temperature. Bruce _______________________________________________ time-nuts mailing list -- [email protected] To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
