I'm working on a thermal balance of a building. In particular, I'm trying to calculate the effect energy gains (mostly due to solar radiation) have on the inside temperature of the building. So I calculated the energy gains per month, for instance, 20 kW for the month of February (it's an extremely poorly insulated building). The only way I know of relating heat, temperature, and mass, is through the equation:(adsbygoogle = window.adsbygoogle || []).push({});

Q=m.cp.dT

where:

- Q is the heat in kJ

- m is the mass of air in kg

- cp is the specific heat of air in kJ/kg.K

- dT is the temperature difference in K

(Note: I'm using the dot to represent thousands and the comma to represent decimals)

So, in one hour, we have 20 kWh, which is 72.000 kJ. For a volume of 637 m3 (the volume of the building) and a density of air of 1,2 kg/m3, we end up having 764 kg of air. If we consider the specific heat of air to be 1,0 kJ/kg.K, then dT is 94 K.

I must admit the number shocked me, so much so that I think I'm doing something wrong. Is there something I'm missing here? Theoretically, if I had a perfectly insulated volume of 637 m3 of air, and I heated it during 1 hour with 20 kW, then it's correct that said volume would experiment a temperature increase of 94Â°C?

Finally, in the case of a poorly insulated building (it has three sliding-glass walls and a corrugated steel pitched roof), how much could I expect the inside temperature to rise in summer? In other words, how can I accurately calculate temperature increase in a building as a result of solar radiation gains?

Thanks.

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# Calculating temperature increase in a building as a result of solar radiation

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