beat the heat for cheap

[Surf]

just based on the heat of evap for water - 970 btu / lb. Each gallon being about 8.5 lb, multiply together

you have about 8000 BTU of cooling throughout the day

that is about 330 BTU/hr of cooling

plz correct me if im wrong

I take it you're assuming ~1 gallon per day evap there? for 2 gallons a day I get about 730 BTU/hr.

You could use an old wet-dry to do the same thing

 

[bkiba]

surf - yea that was my assumption. I'm not sure how they rate a A/C unit - I have a 6000BTU window unit but it must be over some peroid of time.

yea you could use a wet-dry, just need to get the air through it somehow - I'm sure the bioballs would give a good water - air contact surface.

 

[Surf]

it must be over some peroid of time.

It's hours, usually. Larger units are reported (as I'm sure you recall from Thermodynamics ) in tons, where one ton of cooling equals 12,000 BTU/hr.
This comes from the ancient times, when cooling was done by blowing air over large blocks of ice, the ton measurement is the equivalent to the weight of ice melted in a 24 hr period.

For the guy who wondered about frozen water in a gallon jug.

Each lb of ice will give up 144 BTU as it melts, a 1 gallon jug will give up 7.6*144=1094 BTU. keep in mind though, this will be more stressful to the tank as the cooling rate will change over time, and some water will be cooled more than others unless you put it in an otherwise empty high flow sump.

 

[Beenalongtime79]

My question is whether you really need the baffling or PVC/eggcrate matrix at all. I think you could setup a few sprinkler heads and just cool the drops that shower down causing evaporative cooling. Then you wouldn't have to deal w/ the Nitrate problem.

Peace,
John H.

 

[Mr. Ugly]

Each lb of ice will give up 144 BTU as it melts, a 1 gallon jug will give up 7.6*144=1094 BTU. keep in mind though, this will be more stressful to the tank as the cooling rate will change over time, and some water will be cooled more than others unless you put it in an otherwise empty high flow sump.

How about setting up a jockey box like the home brewers use? You could use a coil of plastic tubing fed from your sump by a thermostat controlled powerhead.

 

[Surf]

That would work (I do enjoy a homebrew myself from time to time) But you'd have to build it out of what? Stainless? Titanium? what metal do you feel comfortable with in your tank?

next step is to use a coil of polyethylene tubing. this is fine, but your heat transfer isn't as good as the metal.

Best way I've seen yet: don't heat the tank. Keep pumps external and lights enclosed. But if that doesn't help, putting a fan or two on the sump (or building a cooling tower) will do well. just my .02

 

[bkiba]

rufio - you don't need the internal material, but removing it will decrease your overall contact surface though, making the column not work as well.

Unless you have a very fine spray I would stick with the packing - since there aren't any really good (and readily available) plastic sprayers. I've actually been looking, the best thing is probably a cheap lawn sprinkler.

So the internal packing gives you more surface area for heat and mass transfer and more cooling. To get the same efficiency as packing you need to constuct a bigger column, get a better spray, or do a staged design (which can get more complicated).


Surf -- since you seem to have remembered more chemE stuff than me PM your email address to me, I would like some help doing the calculations for a external evaporative cooling core. Basically I need to work out the parameters for a heat exchanger that will bring cold water from the external cooling tower into thermal contact with the tank water. The basic idea being you don't have to worry about tank evap and you don't have the nitrate issue (if it is there at all).

thanks!

 

[Mr. Ugly]

Originally posted by Surf
next step is to use a coil of polyethylene tubing. this is fine, but your heat transfer isn't as good as the metal.

I'd just go with the polyethylene. Good enough heat transfer to drop a few degrees. For beer, we want a larger temperature drop. Play around with the coil length and flow rate to get the rate of change that you want.

 

[Mr. Ugly]

Unless you have a very fine spray I would stick with the packing - since there aren't any really good (and readily available) plastic sprayers. I've actually been looking, the best thing is probably a cheap lawn sprinkler.

How about doing a high pressure spray to get finer droplets? Kind of like the AquaC spray induction nozzles. You could just use a section of pipe connected to a pressure pump. Drill a few small orifices in the pipe/fitting to help the water atomize as it sprays out. You Can direct the spray against a deflector to enhance the effect.

Yeah, lawn sprinkler... or spray mister nozzle from a drip irrigation setup.

 

[Chrash236]

What about piping water under your house to a container, then piping it back?

Like cutting a hole in your slab digging out some dirt placing a sealed container in the hole with two pipes coming out of it up to the sump covering the hole mixing some concrete fixing the hole in the slab (you now have two pipes sticking out) hooking one pipe up to a mag seven or nine placing it in the sump and turning it on, force would push the water from the container back up to the sump wouldn't this water be cold?

what do you all think? this would be cheap to opperate, and cool lots of water dont you think?

 

[Surf]

up to a mag seven or nine placing it in the sump and turning it on, force would push the water from the container back up to the sump wouldn't this water be cold?

what do you all think? this would be cheap to opperate, and cool lots of water dont you think?

Designed properly, it's possible. biggest problem with the above sugestion is the surface area required may be a bit larger than you think. Also, that Mag 7 just added 70 watts to your cooling requirements.

 

[Chrash236]

humm, got the idea from a foutain I have in my front yard it is a pot that has a basin under it filled with lava rock, and a pump the basin is two feet by two feet and one foot deep, the water in the pot is cold (75 degrees and the outside air around it is 92 degrees, also I only fill it up every two weeks. I mean thats a big swing in temp differance dont you think?

 

[bkiba]

chrash236 - the geothermal cooling you suggest is a good idea - i've seen some plausable setups here before, but it seems easier if you get it done while you are building your house.

One quick energy efficient solution could be taking you RO waste water and piping that through a heat exchanger in your sump - I mean my cold water is freezing that is just wasted energy....

You all must realize now that while I have no problem wasting kW's of energy I find it a great challenge to be energy efficient...

 

[Chrash236]

http://www.aquaticeco.com/index.cfm/fuseaction/product.detail/iid/3941/cid/2178

found these thought it was cool

 

[bkiba]

how about these

http://www.pricegrabber.com/search_techspecs_full.php/masterid=460232#description

http://www.9thtee.com/zipties.htm

I've been using zipties a lot since I began this project

 

[GreatPyr]

Is the top of the cooling tower capped or kept open?

 

[Surf]

Open to let the water vapor out.

 

[Chrash236]

bkiba what do you think the cooling tower would do for cooling if you made it say five feet tall? or higher.

Do you think the contact time would make you evaporate more water?

 

[bkiba]

My cooling tower is open at the top - but it has a baffle. What I'm using now is what looks like a green plastic manhole cover. It has a little hole in it that I can put the shower piper through. You need to put some sort of baffle on the top to prevent the salt spray from escaping all over the place - but you don't want to comprimise your flow too much.

A taller tower will allow for more evaporation - however you need to weigh your parameters more carefully, to little water flow (or too much air) and you will evaporate it all, too much (or too little air) and the air will get saturated and not cool anymore. I think these problems are easier to avoid with a smaller unit. Always add some kind of valve or something to adjust the flow. The other thing you can do if space is limited is improve the packing, if you can get more surface area for liquid-gas contact you will effectivley be increasing the tower height. Focus on the packing material before making the tower larger.

You want a relativley big unit when it comes to this, the one I designed gets approx 300BTU/hr and even with that my tank can still get rather warm when it is really hot.... by all means scale up!

 

[Surf]

Will this become a 'nitrate factory' similar to a bioball chamber? Have you seen an increase in nitrates? Looks really cool! Good job.

IIRC, The "nitrate factory" effect usually doesn't occur until the balls have built up sufficient biomass, in the short term you won't notice anything.