Air compressors room - Heat recovery

[mfqd13]

Hi,

I'm trying to calculate the possible heat recovery from a room where are installed air compressors.
All the books and references that i found approaches this problem the same way: considers 80% of the air compressor power recoverable.

Althoug this approach may be correct, i would like to do exact calculations, because the ambient tamperature of each room that i find in any client is different and also it changes during the year. How can i perform this calculations? (The energy i can find because i have the temperature and volume of the room, but how can i turn this into heat rate?)

Thanks!

 

[CH5OH]

air compressor power = electric kW (compressor consumption)

heat=electric kW-compressor flow x pressure

 

[21121956]

Hello everybody:

Marcos, may be the document "Compressed Air: Reclaim Heat" can be of some help for you.

http://www.osun.org/warm+air+heating-doc-2.html

Saludos

 

[chicopee]

Well figure out the sensible heat from electrical apparatus and the heat of compression from the compressors, both of which can be utilized in your analysis. If the interstage cooling system is with a coolant that heat may not be available in your analysis.
Don't forget that many air compressor rooms smell of oil fumes and are noisy both of which may be objectionable.

 

[chicopee]

Oh, by the way I am referring to reciprocationg compressors on my previos post. Positive displacement compressors have oil baths which need to be cooled and that could be used as supplemental heat,however, I have never seen used as such.

 

[dcasto]

if a reciprocating compressor is 75% efficient, then the best you can capture is 25% of the energy going to the system.

 

[mfqd13]

Hi to all again,

Thanks for the replies.
For what i have seen by your answers and by all my search in this subject, is a practical aproach to consider that the air compressor usually throws away 75% to 80% of the consumed energy, therefor is common to consider 75% or even 70% of the energy to be avaiable to recover.
This is for air cooled compressors, because for liquid cooled compressors, we may recover heat from the liquid-60%-or from the air-10%. This values may change if we are talking about water cooled or oil cooled.
So, with this, i will consider this aproach as the correct one to my calculatitons!

Thank you again for the replies!

 

[dcasto]

NO, an air compressor can't throw away 75% of it's input energy, it uses 75% of its input energy.

 

[mfqd13]

No,

If the air compressor uses 75% of the energy to produce compressed air the efficiency would be 75%.
There's a bit cunfusion there.