How effective would evaporative cooler be utlized this way?
How effective would evaporative cooler be utlized this way?
(OP)
For a 300 sq ft workshop that you'd not want to add humidity into directly with a swamp cooler, what if you made instead a 4" false ceiling of 2x4's on end, covered with thin plastic sheeting of minimal r-value, to blow cooler evaporative air through a serpentine baffle configuration to achieve even contact all along the whole ceiling and plastic.
How effective might that be if that evaporative swamp cooler outside was blowing 70F air into that 4" false ceiling space of 300 sq ft when ceiling air temp inside, just under that plastic, before you turned it on, was 90F?
Let's assume here no heat gain/loss from above the original ceiling, the top of the false ceiling.
Would this setup likely draw much of that 90F ceiling heat off with 1000 cfm evaporative cooler blower 70F?
Any guess what the BTU's cooling total range might be for that 300 sq ft with this setup?
Whatever its effectiveness, would it likely work better just to let hotter air naturally accumulate up at ceiling for largest Delta T, or use some fans to agitate it along underside of ceiling plastic sheeting, even though that might introduce some cooler air from below, lowering Delta T at plastic surface?
Thanks for any thoughts.
How effective might that be if that evaporative swamp cooler outside was blowing 70F air into that 4" false ceiling space of 300 sq ft when ceiling air temp inside, just under that plastic, before you turned it on, was 90F?
Let's assume here no heat gain/loss from above the original ceiling, the top of the false ceiling.
Would this setup likely draw much of that 90F ceiling heat off with 1000 cfm evaporative cooler blower 70F?
Any guess what the BTU's cooling total range might be for that 300 sq ft with this setup?
Whatever its effectiveness, would it likely work better just to let hotter air naturally accumulate up at ceiling for largest Delta T, or use some fans to agitate it along underside of ceiling plastic sheeting, even though that might introduce some cooler air from below, lowering Delta T at plastic surface?
Thanks for any thoughts.





RE: How effective would evaporative cooler be utlized this way?
I'd likely start with a cheap air conditioner and thick(er) insulation.
Mike Halloran
Pembroke Pines, FL, USA
RE: How effective would evaporative cooler be utlized this way?
Structure very well insulated, AC is certainly quick/easy, but for where swamp cooler can work, it's both cheaper to acquire and run, if you've already got free water in a low humidity locale.
I don't know yet, though, if it's even worthwhile fooling with as I'd proposed it above, thus the reason for my inquiry.
RE: How effective would evaporative cooler be utlized this way?
Issues I can see are:
Lack of delta T which gets worse the further you get from the inlet
Your blown air might only be a few inches of water column but that's going to tear your thin plastic sheet
If your inside air gets close to 90%humidity at 70 F them you'll start to drip water from the ceiling!
Ditto any water collecting in the void will add to the load on the plastic film.
Better to blow your 70F air at the condensors of an AC unit to improve their performers or somehow have a blown and more efficient compact HX between your 70F air and 90F air.
Something like this
http://www.fantronix.com/acatalog/Manrose_HR-100-R...
Remember - More details = better answers
Also: If you get a response it's polite to respond to it.
RE: How effective would evaporative cooler be utlized this way?
http://www.climatewizard.com/how-it-works/
Remember - More details = better answers
Also: If you get a response it's polite to respond to it.
RE: How effective would evaporative cooler be utlized this way?
RE: How effective would evaporative cooler be utlized this way?
Willard3, yes, condensation rearing it's ugly head could be a deal breaker in itself, thanks for that.
Let me ask this of you both, hypothetically, if there were no issues with condensation or plastic tearing, and this 'plate heat exchanger' could be incorporated and run at little expense, what would Delta T have to be, at a minimum, in your opinion, to make it noticeably effective cooling internal air and worth having?
Yes, I understand AC and cooling it's condenser coils with evaporative cooler and HRV units (which i especially like and am looking closely at) are smart options, just wanting to know what effect, if this could be done right, that a cooler ceiling might have on internal air temps.
RE: How effective would evaporative cooler be utlized this way?
1) In order to reduce the static pressure inside the cavity, which will make you reinforce the plastic sheeting from underneath, supply and exhaust fans would be needed. If moving in the direction of reducing the flow of cool-humid air to reduce static pressure, then you will have less heat transfer in the film.
2) Even with reduced static pressure, you will have vapor pressure constantly trying to push humid air into the room and up through the ceiling; hence, good vapor barrier should be achieved.
3) Wood of steel within the chamber should be protected/isolated from high humidity air.
4) Ventilation of the workshop, if occupied, is another problem to solve, which might negate the marginal cooling effect of this idea. Even with no forced ventilation, some of the cooler room air will leak out through doors, windows and crevices not meant for air conditioning, being replaced by infiltrated hot air.
5) For increased heat transfer, agitation of the room air, especially closer to the discharge of the supply fan (higher delta T), will greatly increase the heat transfer (removing the insulating film of room air next to the film). Additional fan(s) and energy consumption.
6) You will always have some heat transfer from ceiling surface and elements of the serpentine baffle configuration into the cool-humid air.
7) Useful BTU's cooling total range would depend on all the factors mentioned above, including the ones explained in above posts, on the capacity of your evaporative cooler and on the outdoor relative humidity and temperature. I would also consider the cost of that cooling effect, in fans, in electrical installation, water, materials, work and energy.
Due to economical and practical reasons, I would take the path of indirect evaporative cooling:
https://en.wikipedia.org/wiki/Evaporative_cooler#I...
"Where the spirit does not work with the hand, there is no art." - Leonardo da Vinci
RE: How effective would evaporative cooler be utlized this way?
Remember - More details = better answers
Also: If you get a response it's polite to respond to it.
RE: How effective would evaporative cooler be utlized this way?
Bottom Line; I've got low humidity outside and free water and am exploring most efficient and cheapest way to incorporate some evaporative cooling without adding any humidity from it to inside air. I just want the 'coolth' without the moisture as inexpensively and simply as possible, the fewer moving parts, probably the better.
RE: How effective would evaporative cooler be utlized this way?
RE: How effective would evaporative cooler be utlized this way?
Remember - More details = better answers
Also: If you get a response it's polite to respond to it.
RE: How effective would evaporative cooler be utlized this way?
I was wondering, too, if there weren't cheap fins that could be wrapped around pipe to
increase surface area, too, like I've seen added onto on some wood stove flue pipes...
For lack of room, it'd require to be outside and insulated itself, where what got me thinking
about inside with false ceiling here is it'd be easier to slap up some 2X4's and plastic and
already well insulated above it. Still thinking on it...
RE: How effective would evaporative cooler be utlized this way?
Dryer ducting looks good!
Gems like this https://www.wildsnow.com/17884/how-to-build-air-cr...
and http://tomtomheylen.com/categories/DIY/hot_cold_ai...
Remember - More details = better answers
Also: If you get a response it's polite to respond to it.
RE: How effective would evaporative cooler be utlized this way?
- Shane
RE: How effective would evaporative cooler be utlized this way?
Remember - More details = better answers
Also: If you get a response it's polite to respond to it.
RE: How effective would evaporative cooler be utlized this way?
Been thinking of doing something like that, pipe inside pipe counterflow heat exchanger.
I know it would be efficient and help, I'm just wondering if it'd be more effective than the greater surface area of the whole ceiling as originally proposed, I really don't know.
RE: How effective would evaporative cooler be utlized this way?
Remember - More details = better answers
Also: If you get a response it's polite to respond to it.
RE: How effective would evaporative cooler be utlized this way?
I am rather impressed by the HXs described, especially the first one using dryer ducting as the heat exchange surface. The stuff is cheap and easy to work with and has a lot of surface area and roughness. I'm sure you could hack up something like that that would be effective with a swamp cooler for just a few hours work and a little money. ... and it can be much less of a fire hazard than big sheets of poly film, and take up a lot less space.
Mike Halloran
Pembroke Pines, FL, USA
RE: How effective would evaporative cooler be utlized this way?
Love to know how it turns out!
Remember - More details = better answers
Also: If you get a response it's polite to respond to it.
RE: How effective would evaporative cooler be utlized this way?
http://www.thermex.co.uk/news/blog/605-why-counter...
The diagram above shows a Shell and Tube Heat Exchanger. In the counter flow setup, the fluids are travelling along the heat exchanger in opposite directions. On the diagram above the cold fluid, highlighted in blue, is travelling right to left where as the warm fluid, shown in red and amber, travels left to right. This distributes the heat more evenly across the heat exchanger and allows for maximum efficiency. In theory, the cold fluid can exit the heat exchanger at a higher temperature than the temperature of the hot fluid outlet, although in reality this is very difficult to achieve.