Air Handling Unit Test - Air Heating Problem

[JaredJames]

We are testing an Air Handling Unit, we need to raise the internal temperature by 30 degrees to pass the test, but cannot exceed an energy input of 500W.

It is a completely sealed unit.

We have four fans constantly running, consuming 384W. Firstly, how can I work out what temperature they will raise the unit to? The fan manufacturer says that all energy input becomes heat (due to it being a closed system, but please let's not debate this, just accept it for the purpose of this question and use the full 384W).

Secondly (if part 1 doesn't raise the temperature by 30 degrees), what size heater would we need to achieve the increase?

Box Dimensions: 1.2x1.2x3.0m
Fan Input: 384W
Must not exceed: 500W (but I would like some answers even if they do exceed it to show me what we would need to do to achieve the required temperature increase)


Also, is there a way to work out how many Watts are required to raise the temperature of air by 1 degree celsius in one hour?

 

[russ_watters]

The fan manufacturer says that all energy input becomes heat (due to it being a closed system, but please let's not debate this, just accept it for the purpose of this question and use the full 384W).

Nothing to debate - it's true!

Also, is there a way to work out how many Watts are required to raise the temperature of air by 1 degree celsius in one hour?

Air volume times specific heat times power = temperature rise.

 

[JaredJames]

Nothing to debate - it's true!

I know it's true, but I put that because with someone in work who didn't understand it I had to spend an hour explaining the concept to him and didn't fancy having to go through the same thing again.

Air volume times specific heat times power = temperature rise.

Thank you for this.

 

[JaredJames]

Hi, that gives me 4.23cubic metres of air, specific heat of 1.005kg/kg K and a power of 384W. Which is over 1600 when multiplied together, which is one hell of a temperature rise.

Is the formula correct or am I making a mistake somewhere?