Is This Heat Transfer Calculation for a Box with Heated Liquid Correct?

AI Thread Summary
The heat transfer calculation presented for a box with heated liquid involves determining heat loss through the box's materials and the lid. The formula provided incorrectly treats air resistance as parallel to the resistance of the box wall and lid, when it should be considered in series. This misinterpretation could lead to inaccurate results in estimating how much of the box needs to be covered to achieve a desired cooling rate. Correcting the calculation is essential for accurately predicting the cooling behavior of the liquid over time. Ensuring proper thermal resistance modeling will enhance the reliability of the cooling time estimates.
Robbyj
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Say we have a box made of two materials (a box with an internal lining) and a lid for the box made of a certain material. If I fill the box with a heated liquid and cover a certain percentage with the lid, is the following calculation correct for heat loss in the liquid if you ignore any film or scale effects or am I going about this the wrong way?

delta Qtotal = ([Abox*delta T / (d1/k1+d2/k2)] + [Alid*delta T / (dlid/klid)] + [hair* Aair * delta T]) * delta t

The eventual purpose is to calculate the percentage of the box that needs to be covered by the lid in order to allow the liquid to cool to a certain temperature range in a specific amount of time.
 
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No. The air resistance is in series with the resistance of the box wall and the lid, not parallel.
 

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