Cooling Waters

you need to measure the flow rate of the well. A well can be a source of water as well as a sink for the water, but it will have a maximum rate from which you can take water from it. It will also have a maximum rate at which it will absorb water into the ground water.

You also need to establish if there is any gradient to the ground water. If it is in gravel you may have an underwater river with high volume capacity and you need to draw from upstream and deliver to the downstream. A sand or soil well will have a lower capacity that a gravel well.

You must also make sure you put back pure water that has no contaminants that your process has added to the water. The authorities will probably want permits and drawings etc = costly.

WHat flow rate do you anticipate?

Given the environmental, beurocratic, and technical hurdles wouldn't it be simpler to use a closed loop heat pump scenario? This has the added advantage of letting you choose a heat transfer fluid. Maybe something with a better specific heat, a dye to help detect leaks, non corrosive to your dies, not a constant supply of dissolved minerals as with ground water, ability to keep it pressurized to raise boiling point if needed.

There is probably not any good advise out here, nor should there be. The absence of any indication your location, and the few details you've provided are utterly insufficient to give any kind of informed answer. Also, your concept of "injecting" by releasing into a second well is not injection...and wells (and aquifers) do not function the way your plan seem to be indicating. You would also have to determine the effect of your "injection" process and location on your existing extraction well. The advise by Guest No. 1 is advise that you would do well to heed. Your starting point for such an idea should be with your local water authority...although I find it doubtful that permission would be granted; and if it were, you would probably be looking at a huge capital investment. It is almost certain that introducing contaminants (including heated water) into any aquifer, especially one from which public drinking/irrigation water might be drawn, will not be tolerated...and attempting to do so without permit could portend ruinous consequences for yourself. A much better plan--also expensive but probably much less so than what you are proposing--would be a surface reservoir, if you can obtain permission, and if it is possible at your location. Another approach is the use of reservoir tanks combined with evaporative cooling towers. But the aquifer injection route is, more likely than not...a non-starter from the get-go.

well, I do know that recharging aquifers is quite doable and is encouraged as long as the water is not changed. Irrigation is an indirect method of recharging aquifers and you are permitted to add some fertilizers to irrigate crops.

I agree that if potable water is drawn from the aquifer then you will have to satisfy the local authorities that it is not changed.

In addition, a large emoung of hot water injected can raise the temperature of a large subterranean area and it may change the dynamics and lead to subsidence.

Cooling tower is a good idea/

The point of my comment was that it is the effect on the aquifer that should demand highest concern, and not what is do-able, or what is most expedient (or possible at all) for a commercial enterprise. Said another way, the aquifer is not the property of any one party to exploit as that party sees fit. Thus the management, use, and conservation of aquifers is, and should be, under public control...for the benefit not only of the public at large, but also of the aquifers themselves. To understand that, one need only consider the considerable depletion of, for example, the Ogallala aquifer--a once huge reservoir that was hundreds of thousands of years in the making--to only a small fraction of its original capacity in some locations--all for the sole benefit of a relatively small number of powerful agricultural interests bent on producing crop yields far, far in excess of any potential use or market. Or the fact that, of all the underground water that once existed in the United States, for example, the greater part has been depleted...and it has been depleted not during the entire history of farming and other human enterprises in this country, but during the last 50 or 60 years! While you speak of aquifer recharge by natural means from crop irrigation runoff--albeit that (1) the objective of any farmer should be to limit water extraction to the minimum amount needed...such that there will be little or no run-off, and (2) the type of aquifer will play a role as to its recharge capacity and rate--it was injection--direct injection--of deeply mined water--that the thread leader is proposing for his plant. Since deep lying water is most likely to reside in rock strata, and since such an aquifer is most likely to be one for which we would be looking at recharge cycles measured in years, decades, or even centuries, then it is also more likely that any effort to recharge such an aquifer for use in a continuing, use-recycle-use again process would entail forcing the water underground under very high pressure...or injecting water at least as fast (within reasonable limits) as it is extracted. Another distinction attending your example, is that the extraction of the irrigation water occurs on a seasonal basis--with a respite between extractions during which recharge of at least some of the mined water will occur naturally, either from the farm itself, or from other, naturally occuring/recurring sources. The thread leader does not state whether or not his extraction would be so limited as would a farmer's, or whether his productive process would terminate seasonally in order to permit such natural recharge...either from distant natural sourcees, or from the well which he supposes will permit the water to just sink back into the aquifer of its own accord. Finally, the reason I posted was not to take issue with your post but, rather, to indicate, as did the guest, the possibly prohibitive obstacles that might be faced--indeed, that ought to be faced--by anyone "needing" or considering such conversion of natural resources to personal, for profit use...and to indicate that there are other possibilities that might be more effective, less problematic, and less expensive...as well as more environmentally sensitive. Thank you for your counterpoint.

Hi Ira,

Interesting but costly. You must be where water is priced close to gas to consider this option.

First, it is easy to retrieve water from an acquifer. Returning directly is one problem - unless you're dumping into the mississippi. Environmental concerns and risks are $$$ risky - unless you are in China. Been there done that.

The other problem is the condition of the water. All molding equipment - extrusion, injection, etc is best served by purified, distilled, conditioned soft water. It prevents scale and mineral deposits from forming on the walls of the equipment and molds thereby reducing heat transfer efficiency. This extends the life of the equipment and molds from 1 year to 10 under normal conditions. As imagined, costs increase as cooling efficience decreases.

The best option is a heat transfer station (could be as simple as a cooling tower - based on relative humidity) over a closed loop system circulating conditioned water. You should not lose the conditioned water in the cooling circuit - simply cool and recirculate. The heat transfer could occur in a heat transfer coil in an acquifer/well/flow station or by an evaporation tower. Water to the atmosphere is better than to the ground - less risky too. Hope this helps..

Call the City of West Palm Beach, Florida. WPB has used "Deep Well Injection" for years to dispose of their waste water.

Bob G.

Bob,

The implicit suggestion that WPB and similar sea- and below-sea-level coastal communities use ground-water-recharge injection as a means (in similar fashion as a septic system) of filtering sewerage--or that it is a process translocatable to all but a relatively few specific locales--could be somewhat misleading....

• It is capital intensive process generally requiring public financing...and not affordable, or generally available, to private persons.
• It is treated waste water that is being injected, not raw, sewage-laden water.
• It is a process that is location specific, done not so much as a matter of choice but out of necessity based on (population growth related) previous experience with derogatory impacts apart from water supply depletion...
• to prevent land surface subsidence...sometimes precipitous
• to prevent sea (i.e., salt) water intrusion and contamination of water reserves due to water table lowering (i.e., lowering of the natural sea water barrier) that might otherwise occur

Indeed, in such an environmentally sensitive place as Florida--with its yellow-brown pure tap water so discomfitting to visitors --it would be reasonable to expect that the strictures pertaining to groundwater exploitation by private concerns would be among the most heavily monitored and enforced.

Hi all

First let me thank all of you who took the time to answer.

1. We already have a cooler that we want to eliminate due to very high cost of electrical energy here, (We are located in Santiago Chile.)

2.Without any doubt, whatever we do, if we do it, will be in total compliance with environmental considerations, whether obliged by law or not. (we are VERY sensitive in this respect).

3.Our aquifer is the remaining of an old swamp (confined) starts at -15' down to about -250' with high content of minerals. It is not potable, and causes lots of scaling problems with our cooler. Adding water softeners, will only increase costs, and on regeneration will deliver high quantities of brine solution which needs to be treated before it is sent to into the central sewer system, which means more expenses.

4. Q in our case is 20L/sec or aprox 300Gpm, the return is the same. contamination due to the cooling process in negligible. Delta T is less than 10C.

5. I have been told that we can just let it flow back into the second well which is 100' away, and with this (small) amount of water, things will take care of themselves. I am not so sure. This is not a gravel rich aquifer. and I suspect I will have an overflow, this is the biggest concern I have. Is there any test I can conduct to study the aquifer capacity to accept water?

What tempts me, is the obvious saving , several thousands dollars a month, in electricity alone!. but when things look too nice I become very suspicious. Problem is that a pilot plant is not an option.

Am still in the dark and Will very welcome you comments gentlmen.

Ira Curtis.

Yes, such a small amount of water that has had nothing added or taken away and is just a little warmer should not be a problem.

As for capacity. Watch how the level falls if you fill it above the water level to the surface. See how much that takes to fall 2 feet below surface and from that you can deduce a liters/minute flow rate.

To enhance the flow rate place a 10 foot section of screened tube into the outlet to avoid gradual blocking of the aquifer by the packing of the exposed surface under the current flowing into it. The larger the screen area the faster the aquifer will take water and the less liely it is to block.

SCreened inet is also good as it avoids sucking a cavity in the aquifer which can cause a ground collapse

Ira,

What you propose is a standard industry practice but, the mechanics of injection wells require significant engineering and have some inherant design flaws. I have been in this business for 41 years, and one thing I can tell you is: Get a pro to do the work and be prepared to spend some money.

If you would like some design help, e-mail me at rockbit8@hotmail.com

Wayne Nash

Ira it is hard to give advice on this but if you are not talking about millions of liters a day a solution could be to have a half way storage facility between waste or hot water and the well. You could simply cool the water there and reuse it. This would reduce out take and input at the same time. If you are in any way inerested in this solution please let me know and I could intoduce you to a very cheap way of cooling water quickly. You could buy the parts in any good hardware store. Good Luck.Ky

3000 pounds/minute times 18F = 54,000 BTU/minute. The high % of dissolved solids stops you from using a cooling tank unless you had unless you had about 10 GPM new water and allowed 10 gpm to flow back into the other well. That would simplify the problem, but you would have to make a tank with a long serpentine path(like a swiss roll on end) to allow the water to cool. You have enough water flow to fill a channel or ditch 1 foot square and 47 feet long each minute~3000 lbs/minute. So to cool it to ambient you would need about 1000 feet of such a channel. A simple tank of that capacity would not do, you would have to create baffles that made a long path in the tank of close to that 1000 feet.

So you must test the aquifer to see if it will absorb that 300 gallons per minute.

A simple way is to simply pump new water from the source into the discharge well for a few hours and see if you get any blocking. If you get blocking you must create an antiblocking path from pipe with mesh on the outside that goes into the marsh and down 50 feet or so and has mesh holes along it's length. If you can draw 300 gpm froma well, you can probably dump 300 gpm if you simply add some mesh pipe lengths. They would be easy to drive with a well tip on the end.

Knudsen plast has done this for years. Contact them and get help www.knudsenplast.dk

Ira,

You will have scale and corrosion build-up on your circuits and equipment unless you treat the water and remove all minerals. The scale buildup will result in decreased life of your equipment and decreased cooling efficiency. Another option is to use the aquifer water to cool a closed cooling circuit. I have set up injection molding operations in most parts of the world. If you wish, please contact Nypro (China, MX, Europe, & US), CARCLO (US, China, Europe & UK), JARDEN (SC - USA) or UFE (MN - USA). Best of luck with your project. You may contact me directly at jgriffin@nagatechnology.com.

It is always best to have more than one option. You already have a cooler so go ahead and hook up your second well and keep your cooler in the loop when the second well gets backed up you can switch over again to the cooler. You will have saved at least some electric expense during that time. You can then spend some of the money you have saved on electricity use and invest in an appropriate alternative energy production method on site. By tying into the existing electric you will be able to reduce your energy costs while slowly building a modularized energy production facility, for example solar: you make an initial investment to set up the regulation and controls then you buy panels as afforded from surplus outlets etc so that you are building your system steadily and affordably month to month with the energy you have saved from the well and those solar modules you have in place. You will be able to ween yourself from the electric source you now use and you will be able to eliminate the well down the road so that you are back to using clean water from the cooler. My personal view favors mfgs producing their own power and even becoming self subsistent from all public use, but that is just my personal opinion.

Another alternative is to use a "Wet Surface Air Cooler". A WSAC operates like a cooling tower/heat exchanger combination but uses significantly less energy and make up water.

Delta T Heat Exchangers