Heat transfer equation - formulation

AI Thread Summary
The discussion focuses on calculating the heat capacity and heat loss coefficient of a heated device using the equation dQ = CdT1 + γ(dT2)dt. The user is uncertain about the term dT in γ(dT2)dt, questioning whether it represents the temperature difference between the device and its surroundings or if it is synonymous with dT1. Clarification is sought on the correct expression for heat loss in this context. Understanding the relationship between these temperature differentials is crucial for accurate calculations. The conversation emphasizes the need for precise definitions in thermal equations.
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Hi, I have a device which is heated from inside by constant heat (let's say by Joule's heat - UIt). Some heat causes temperature rise of the device, some is lost into surroundings through device's surface. I measured how temperature of the device varies with time and I want to calculate constants like heat capacity of the device and heat loss coefficient.

But I'm not sure whether my equation is correct:

dQ = CdT1 + γ(dT2)dt

dQ=UIdt
C - heat capacity of the device
γ - heat loss coefficient
dt - time differential
dT1 - temperature differential (of the device per dt)

I'm confused about last expression in the equation: What does dT in the expression γ(dT2)dt mean? Is it the same as dT1 or is it rather instantaneous temperature of the device minus temperature of surroundings?
 
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Anyone? I just need in what form/terms we express heat loss...
 

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