Evaporative Cooler

[sphelps]

As requested a fairly easy DIY project for effective energy efficient cooling.

The idea is similar to simply running a fan over the water surface. However with this method you're increasing the surface area and contact time between the air and water. In addition it presents the ability to vent the exhaust humid air outside or to a more appropriate location.

It's efficiency is based mostly on the humidity of the air fed into the cooler. The less moisture in the air the better it will work. However the water and air flow should be controllable as it's important to be able to control contact time in order to tune the cooler.

This is one I built myself. More as a prototype, once I figure out what will work best I'll redesign it and likely build it into my new sump.

http://i11.photobucket.com/albums/a174/sphelps/June%2016%202008/evapcooler1.jpg

http://i11.photobucket.com/albums/a174/sphelps/June%2016%202008/evapcooler2.jpg

I designed to fit in the new cabinet.
http://i11.photobucket.com/albums/a174/sphelps/June%2016%202008/evapcooler4.jpg

http://i11.photobucket.com/albums/a174/sphelps/June%2016%202008/evapcooler3.jpg

I built it from clear acrylic, you could use various other materials. Next time I would use mostly black acrylic to prevent light and algae growth.
http://i84.photobucket.com/albums/k36/EngineeredAquariums/DSC_0008.jpg

http://i84.photobucket.com/albums/k36/EngineeredAquariums/DSC_0009.jpg

http://i84.photobucket.com/albums/k36/EngineeredAquariums/DSC_0013-1.jpg

I connected a 3" PVC pipe line to connect the cooler exhaust air to an outside vent. I also ended up mounting it a little lower than planned for better water flow.
http://i84.photobucket.com/albums/k36/EngineeredAquariums/DSC_0020-1.jpg


I'm still working on the final design. As it stands it can produce about a 4 degree temperature drop from 84 to 80 degrees on an average day.
System volume is approx. 200g
628W of lighting
2 reeflo pumps
Everything is pretty sealed up and has little exposure to the surroundings for heat exchange.
On the really warm days my place has been getting up to 26 degrees C indoors. It has also been fairly humid lately so the cooler has only been able to drop the temp to 82 degrees. If I run the air conditioner to keep the room with the tank only (not filtration) at 23 degrees C the cooler will maintain about 80.2 - 80.7.

Ideally I would like the new design to maintain the tank temp at 80 without having to run the AC.

I'm open to questions and suggestions.

[michika]

Thank you!

How did you learn to do this? Something job related?

How do you tweak it and adjust it?

[crtrcrzy]

sphelps is an engineering graduate ive seen alot of his stuff first hand and hes also built me alot ,like he says hes always reingineering his early work. i have never been disapointed

[spreerider]

ive used a few evaporator coolers and they all used wicks and a mesh but this method looks alot more reliable for salt water.
good idea, but i bet you will be using alot of water, do you have an auto topoff?

[sphelps]

Thank you!

How did you learn to do this? Something job related?

How do you tweak it and adjust it?

No problem.

I was researching various heat exchanges and their adaptability to the aquarium and found the evaporative cooler design to be most logical. Researching that I found a few on the market but as stated they use foam which to me seemed troubling so I decided to try something a little different.

I adjust it by paying around with various flow rates of air and water until I find something that seems to work best. The fans are controlled by a variable 3-12 volt adapter and the water with a ball valve. The cooler is fed by overflow from the skimmer so it doesn't require an extra pump. Only power it uses is from 4 low wattage computer fans. Uses less than 12 watts.


sphelps is an engineering graduate ive seen alot of his stuff first hand and hes also built me alot ,like he says hes always reingineering his early work. i have never been disapointed

Thanks Greg, good to see you're happy. We'll have to get you to post some recent pics of your setup. It's been a while :biggrin:


ive used a few evaporator coolers and they all used wicks and a mesh but this method looks alot more reliable for salt water.
good idea, but i bet you will be using alot of water, do you have an auto topoff?

Yes I have an ATO, direct RO hook up. Not sure how much water I use but water is cheap.

[brizzo]

Do you get much salt creep from your design? I'm assuming the pics were fresh after install :)

[sphelps]

been up and running for a month and no salt creep yet. It's likely to show up eventually but that's why the unit is designed to be easily removed and cleaned.

[rdnicolas]

Interesting idea, how much has your water consiumption increased?

[sphelps]

Interesting idea, how much has your water consiumption increased?

No idea, but probably added about a half gallon a day.

[Jack]

The Deltec evaporative coolers use rolled up "DLS"; the closest DIY equivilant I can find is gutter guard from Home Depot. I would give that a shot. It doesn't look like the egg crate is giving you maximum surface area for cooling.

[michika]

I've been fiddling around with this idea since you posted it, and I really like it. How would I go about figuring out the sizing for this evaporative cooler on a much much larger system?

[sphelps]

Basically for larger systems I would simply go bigger than you may need, ideally it would be controlled by a some kind of temperature controller so you couldn't really go too big. Larger fans should be used, you probably wouldn't be able to get away with computer fans for larger units.

Also FYI, I tried using gutter guard instead of eggcrate and found the eegcrate to actually work better. It's less restrictive to air flow and it produces just as much surface area for contact if not more. A finner mesh will only increase the surface contact between the mesh and the water, not the air and water. It's not a bio-filter :razz:

[drydock]

Hi,

Sorry for hijacking your thread...

I have seen those computer fans used in a number of applications. What do you use to power them? I would like to integrate a couple into a tank canopy to cool my lights.

[sphelps]

Hi,

Sorry for hijacking your thread...

I have seen those computer fans used in a number of applications. What do you use to power them? I would like to integrate a couple into a tank canopy to cool my lights.

An AC to DC adapter, usually 12VDC but anything from 6-14 will work but fan speed varies with voltage. The adapters with an adjustable output in that range are nice so you can adjust the fan speed as needed or until you get an acceptable noise level.

[slakker]

This is really cool (pun intended)... :)

I was wondering, would you play with putting a peltier device on this?

[sphelps]

I was wondering, would you play with putting a peltier device on this?

I don't really see how a this device would serve a purpose in an evaporative cooler. Can you maybe explain your idea?

You're basically taking about a thermoelectricity but how would it be applied, to there air or water? Air would be better warmer and cooling the water inside the cooler would be difficult since it's dripped through and it would actually cause the system to work less efficient since the idea is to evaporate water. Basically I'm a little confused with your suggestion, it's a different system all together, kind of like combining a chiller and an evaporative cooler, I'm just not sure how they could be integrated.

[slakker]

I was thinking maybe making it a "combo" cooling device. I like how compact you made the whole sump unit and maybe to increase the cooling capcity more by putting the peltier in contact with the outflow. So one of those iCA nanochiller or "ice probes"... they're small and can be controlled with a Neptune... not sure how much more effective it would be, but wanted to see if you have any experiemental info/data on it.

[untamed]

I ran one of those iceprobes for many years on my 30 gallon hex. It wasn't very effective, even on a 30 gallon system. I don't think it wouldn't make any significant difference to the performance of this idea.

[sphelps]

I was thinking maybe making it a "combo" cooling device. I like how compact you made the whole sump unit and maybe to increase the cooling capcity more by putting the peltier in contact with the outflow. So one of those iCA nanochiller or "ice probes"... they're small and can be controlled with a Neptune... not sure how much more effective it would be, but wanted to see if you have any experiemental info/data on it.

You're basically taking about one of these:
http://www.aqua-digital.com/components/com_virtuemart/shop_image/product/67a573c423d122233a0e2f0d07119782.jpg

Problem is it would really be impossible to integrate into an evaporative cooler since they work on completely different principals. Also the idea behind the EC is be cost effective and efficient. The device above would probably use about 1000-1600 Watts to be beneficial on my system, and costs about $1500 so...

[slakker]

I was thinking more just the device itself, so without all the bells and whistles... you can get them as cheap as $120 but not sure the specs on it... It wouldn't be adding to the evaporative properties, but in line... But given what Untamed said, it's probably not worth it...

[StirCrazy]

one sugestion to increase efficency, is to use somthing other than egg crate to creat a multi teared spill over (same idea that they use in the big cooling towers for refinerys) I don't think you could add it to yours as it might take a different configuration for air flow. The problem I see in your design is the water flows to the bottom unrestricted and quickly so I do't think you'll get much more cooling out of it. I have been playing around with this for a while trying to come up with a set up that is quiet enough to be in the same room as the tank.

basicly you have the water spilling over the sides and they are kinda stepped but instead of 90 degree steps it is like little "v"s so it fills up them spills into the one below and so one.. then the air blows upward in the oposit direction to create a counter flow open loop type design to minimize the foot print.

Steve

[sphelps]

pics? Extra contact time would definitely help

[StirCrazy]

pics? Extra contact time would definitely help

I'll see what I can come up with for a pic. everything has been stuffed in dark corners and packed away sence I took down my big tank.

basicly you need to use a spary nozzel to put the water in at the top, then have a series of trays, to catch, fill up and over flow, while sucking air from the bottom to the top.. trick is being able to make it not leak haha.

I have been looking for something better to make the louvers, or make them my self but haven't found anything I am happy with yet.

Steve

[sphelps]

I'll see what I can come up with for a pic. everything has been stuffed in dark corners and packed away sence I took down my big tank.

basicly you need to use a spary nozzel to put the water in at the top, then have a series of trays, to catch, fill up and over flow, while sucking air from the bottom to the top.. trick is being able to make it not leak haha.

I have been looking for something better to make the louvers, or make them my self but haven't found anything I am happy with yet.

Steve
Number one rule in engineering is keeping things as simple as possible, your design is starting to sound pretty complicated for what's required, but I'm still interested and would like to see pics or a diagram if possible.