Limits of Evaporative cooling on air
Limits of Evaporative cooling on air
(OP)
I am undertaking a basic cost benefit study of an air cooled condenser. Part of this includes looking at the maximum theoretical benefit of a spray/misting cooling system. Based on evaporative cooling, I am trying to provide data showing theoretical cooling of air from a start temperature for a range of Relative humidity's.
e.g. plot possible temperature change of air at 30 degC from 0-100% Rel Humidity start points.
(Obviously start at RH 100% = 0 degC temp change, but start at RH 50% = ? temp change)
Can I do this from steam tables and saturated air pressures?
Trawling the I-net has confused me. Any thoughts?
e.g. plot possible temperature change of air at 30 degC from 0-100% Rel Humidity start points.
(Obviously start at RH 100% = 0 degC temp change, but start at RH 50% = ? temp change)
Can I do this from steam tables and saturated air pressures?
Trawling the I-net has confused me. Any thoughts?





RE: Limits of Evaporative cooling on air
RE: Limits of Evaporative cooling on air
In your case, you want to lower the dry bulb temperature of the condenser air.
Sometimes when a condenser is on a roof the air can be a lot hotter than the ambinet at the ground. Makes a opportunity climate for evaporative cooling even in humid climates.
Cool down that air that has been heated to 120F on the roof before it hits your condenser coil.
Take the "V" out of HVAC and you are left with a HAC(k) job.
RE: Limits of Evaporative cooling on air
So would have to look at the basics of pyschrometrics -- dry bulb temperature and the pounds of moisture per pound of dry air.
Take the "V" out of HVAC and you are left with a HAC(k) job.
RE: Limits of Evaporative cooling on air
RE: Limits of Evaporative cooling on air
Take the "V" out of HVAC and you are left with a HAC(k) job.
RE: Limits of Evaporative cooling on air
RE: Limits of Evaporative cooling on air
Take the "V" out of HVAC and you are left with a HAC(k) job.
RE: Limits of Evaporative cooling on air
However, practically, 70 to 75% of wet bulb depression is generally considered for evaporative coolers. You can download psychrometric charts from the first two links below. The third link is a spreadsheet.
http://www.uigi.com/psychrometry.html
Psychrometric Chart
Psychrometric Spreadsheet
RE: Limits of Evaporative cooling on air
I always like the 11x17 trane chart, that is laminated. Basic examples on the back of it, easy to read the dewpoint from.
Take the "V" out of HVAC and you are left with a HAC(k) job.
RE: Limits of Evaporative cooling on air
Another suggestion is that if you agree with the data on the tables, you could use excell, to give you an equation (best curve fit) for each set of data in terms of simple X and Y.
Then you can use the equation in your modeling calculations.
regards,