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# Ventilation area inlet

## Ventilation area inlet

(OP)
Hello
I need to calculate the necessary area (m2) of the inlet in a building where a heatloss of 24 kW is dissipated. There is a distance of 2,8 m between openings of inlet and outlet.
There are two scenarios:
- natural ventilation
- forced ventilation

I am looking for formulas or litterature explaining how to proceed.

Also how to calculate necessary airflow (m3/s)

Best regards
Hans-Henrik
Replies continue below

### RE: Ventilation area inlet

Ventilation heat dissipation can be boiled down to a pretty straightforward Q=m_dot*c_p*(T_out-T_in). To start take a look at ASHRAE Fundamentals Chapter 16 (its Ch16 in the 2009 version at least) "Ventilation and Infiltration".

### RE: Ventilation area inlet

(OP)
HelloGBTerpenhow
Thank you so much. I am familiar with the energy dissipation formula.
Do you by any chance have pages from ASHRAE chapter 16, adressing ventilation inlet area calculation. I am not an expert on HVAC since I am a power Engineer😉

BR. Hans-Henrik

### RE: Ventilation area inlet

There are a huge number of variable here to start thinking about before you can start to make any progress.

Temperatures? Assumed air temp coming in, max surface temp of your units, max air temp leaving, max air temp in the building ( if people are there it might be quite low).

Ventilation route - 2.8m where? vertical? horizontal?

Volume of the building

What sort of heat output / exchanger ( fan driven ( like a motor for example) or convection ( like a hot plate / surface ) heat from combustion ( like a large gas ring for cooking?)

not sure any literature is going to get you anywhere where anyone else is comfortable with the answer. There are lots of companies and engineers who do this for a living.

Remember - More details = better answers
Also: If you get a response it's polite to respond to it.

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