TxAg20 said:
Their effectiveness is inverse to humidity. In the dry heat of west Texas they're incredible. In the hill country, they're helpful. Either place, you have to be directly in front of them to feel their effectiveness if you're using them outdoors.
Depends on the size of the unit. $500-6k I think is a close range.FunkyKO said:
How much do they go for? High - low.
lawless89 said:
they actually only add 2% humidity to the air. So if it's 90% humidity, the difference is minimal.
nonameag99 said:
Any idea if cool/cold water helps evap
I forget my thermo
AgEng98 said:lawless89 said:
they actually only add 2% humidity to the air. So if it's 90% humidity, the difference is minimal.
RH is a measure of air's capacity to hold moisture, not the amount of moisture in the air. When the air is that close to saturation, it simply can't evaporate much water, so evaporative cooling won't make that much difference.
Evaporative cooling will increase RH significantly (not that it really means anything since RH is a pointless metric). Take extreme design (99.9%) conditions for Houston, the cooling design point is 94 F at 47% RH (77 F wet bulb). Wet bulb is the limiting factor here. Assuming an evaporative efficiency of 75% for a 6" pad, you'll end up with an exit temperature of around 81 F and the coincident RH will be 84%.
The only time it's 90% RH anywhere is just before or after the air temperature has cooled to the dewpoint. It's certainly not in the heat of the day when you'd be using evaporative cooling.
As a general comment, evaporative cooling works just fine in humid climates if you couple it with air movement. Every single commercial animal housing system (chickens, turkeys, swine, dairy) in the Southeast US uses it because it works.
The biggest issue in this application is that you don't have adequate cfm to cool the "space" and your distribution will be terrible. You'd probably be just as good to get a high pressure fogging system and multiple smaller fans.
AgEng98 said:
Evaporative cooling is adiabatic. You're simply swapping sensible for latent. No sensible heat removal.
AgEng98 said:lawless89 said:
they actually only add 2% humidity to the air. So if it's 90% humidity, the difference is minimal.
RH is a measure of air's capacity to hold moisture, not the amount of moisture in the air. When the air is that close to saturation, it simply can't evaporate much water, so evaporative cooling won't make that much difference.
Evaporative cooling will increase RH significantly (not that it really means anything since RH is a pointless metric). Take extreme design (99.9%) conditions for Houston, the cooling design point is 94 F at 47% RH (77 F wet bulb). Wet bulb is the limiting factor here. Assuming an evaporative efficiency of 75% for a 6" pad, you'll end up with an exit temperature of around 81 F and the coincident RH will be 84%.
The only time it's 90% RH anywhere is just before or after the air temperature has cooled to the dewpoint. It's certainly not in the heat of the day when you'd be using evaporative cooling.
As a general comment, evaporative cooling works just fine in humid climates if you couple it with air movement. Every single commercial animal housing system (chickens, turkeys, swine, dairy) in the Southeast US uses it because it works.
The biggest issue in this application is that you don't have adequate cfm to cool the "space" and your distribution will be terrible. You'd probably be just as good to get a high pressure fogging system and multiple smaller fans.
