Calculating Heat Convection Output: Clarification Needed

AI Thread Summary
The discussion focuses on clarifying the formula for calculating convective heat output in cooking appliances, specifically the variables involved. There is confusion regarding whether to use the appliance's actual capacity or its power rating for 'Pn', as this choice significantly impacts the outcome. The term 'Qs' is identified as the sensible heat emitted, which can be expressed in watts or kilowatts. Participants speculate on the meaning of actual capacity and its relation to cooking efficiency, particularly in the context of an electric oven. Overall, the conversation seeks to clarify these technical aspects for accurate heat output calculations.
afa13
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I need some clarification regarding the following formula:

Qconv = Pn x Qs x b x ϕ

this equation is used to determine the cooking appliance's convective heat output in kw, 'b' and 'ϕ' are coefficients easily determined. I am confused whether to use the actual capacity of the appliance for 'Pn' or its power rating which is higher and will result in a big difference. And 'Qs' is the sensible heat emitted in W and sometimes is expressed is W/kW.

Can anyone help clear this issue?
 
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What do you mean by actual capacity is it scones per minute? I take it is some kind of electric oven. Is it a electric element in a oven where you are trying to work out the ratio of radiant heat to convective heat? Maybe the sensible heat in W/kW is a ratio of sensible heating to total heating ie the heat to heat up the scones divided by the heat to heat up the scones plus the heat of the steam coming out of them. Maybe you should not listen to me I have never studied oven design.
 

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