Water Aeration

What about pumping a bit of ozone into water? It should disinfect.

Water is a good thermal mass, but won't it have potential problems with condensation as well? Do you mean 90 F or C?.

I'd have thought hot air blown through rubble may be less problematic....but obviously air is much poorer in terms of thermal mass/conductivity.

This ties in with my Q, about my back rubber roof, if air was blown over this it could extract the heat nicely. Trombe walls and all that stuff.

I'd love to build a house from scratch....bit old now and land is V expensive in UK.

Best of luck and have fun.

90 degrees F.

If condensation proved to be a problem, it could probably be solved by placing a layer of plastic sheet over the water. Air bubbles could still escape horizontally to the edges. This is planned for an arid climate.

Ok...

I'm under the impression that 60C will kill the bugs in your water...surely pumping extra air through water at 90F will just encourage growth of nasty stuff?

I reseve the right to be wrong as I'm not a biologist...

I would think you are going to end up with UV or chemical treatment to keep the bugs down...it just sounds like a bit of a health hazard to me...make your own primordial soup!

I don't mean to sound negative...but it's better to ask those questions now!

I believe it's the same principle as a fish tank. Keep the air oxygenated with a bubbler and it stays clean and odor free. Once water loses its air is when it gets stinky, I think.

Just in case you do have problems, there are pool treatment products which do not rely on chlorine and are odourless, not sure if it is available in the US yes. Google 'Poolsan'.

If you are in an arid region a bit of extra humidity might be nice anyway!

I'd recomend plenty of research just in case.

Best of luck

Del

A fish tank also has a filter. Agitating with air can and will promote growth.

To keep the nasties out (smell and growth) in this house project, you'll need to exchange the water through a filtration system (bag filter as an example) at a high rate, possibly a couple of times per hour. Makeup water (you'll lose a lot at anything higher than ambient) will have to be R.O. water not city water otherwise you'll quickly begin to experience even more problems.

A lot more thought is going to have to go into your project in order to be successful. I would advise you consult someone with more experience.

90degF is just the right sort of temperature to encourage biology to grow.

Ultraviolet light may be a suitable way of preventing it.

If the water is only intended to be used as a heat transfer and storage medium, and not for drinking, then suitable additives might be applicable. What about central heating inhibitors, sometimes colloquially known as "Fernox" (usual disclaimer)?

Good project! Initially, what type water do you intend to fill this reservoir? well water or just city water from the utility supply? If you use a high TDS water, some scaling may also become a problem in the future, especially if there is a heat exchange in your pipes. To distribute the heat in the water mass, you need to have some sort of agitation or stirring. This can be provided by a circulation pump and if you circulate with a centrifugal pump, you can also incorporate a venturi type aerator which can be opened to suck air from the atmosphere. The amount of air is not critical since there is a saturation point for water to absorb air. The air absorption is dependent on temperature, contact time,method of air injection, water quality, etc.

It is not necessary to run the pump 24 hours, you can provide a timer to schedule a pump run for certain number of hours.

I would suggest a provision to easily drain the water in case there is a need to change the water or to access the tanks for repairs.

I'd be using well water and/or roof capture rain water. The softness of rain water is astounding.

The water itself does not circulate. The heat is exchanged into it by running propylene glycol (What else?) that circulates through solar collectors in a 1-1/2" copper pipe. By having a few 90's in it to facilitate expansion contraction the high conductivity of the copper immersed in the water resevoir should work.

The air injection venturi idea sounds totally cool. Thank you

Please, what (or would it be, what all?) is your underhouse pool going to achieve, exactly? Maybe posting a sketch of your concept (better still, concepts, and the synergies among them) would be a good idea? Otherwise, seems the possibilites are so numerous that it's gonna be near-impossible to get any cohesive discussion going? Such a concept drawing might include pathways to/from the surrounding air and ground environments, in addition to inside/within the structure.

Point 2. You must be a corporation unto yourself? or very rich?...hoping to get permits?

Point3. This may sound a bit off but, why not a subterranean house...possibly with the water reservoir above instead of below? Maybe even waterproofed photovoltaics lining the pool bottom? Don't laugh; just trying to stimulate some grandiouse ideations, huh?

Point 1.

It's simply roof mounted solar hot water collectors heating propylene glycol with enough velocity to assure turbulent flow. The fluid circulates down the west wall, into the resevoir, transitions to copper pipe through the water storage, exits the east end, and back up to the roof as a closed system.

Point 2.

By keeping things totally simple, I don't think it will cost much. Why not utilize all that foundation wall concrete as an enclosure. I believe a pond liner, being totally protected from UV degradation should last a long time. Maybe even use multiple liners as a redundant back up.

I'm as poor as a church mouse but feel compelled to do not as others do. I hope that where there's a will there's a way will prove true. As long as one is being adequate to the moment, the next moment will somehow take care of itself.

New Mexico is a progressive state and I hope will cooperate with me. The prudent thing to do is to build a 16 x 12 foot (sub 200 square feet not requiring a permit) and let that lesson speak for itself. Seeing is believing.

Point 3.

I love the idea of subterranean, after all we all end up there eventually. Sun and natural light is too important for me to improvise alternatives.

Can't speak from experience (yet), but having researched around this topic a lot you might find you are far better off using the great thermal storage medium right under your feet...the earth.

Rather than heat exhanging to an underground pool (and my guess is that this pool will end up leaking / collapsing / devouring your house / giving endless damp problems / attracting foul demons from the netherworld), simply (ha ha) drill some holes into the earth in the centre of your site, put looped pipes down the holes and fill them with concrete (there are high heat-exchange concrete mixes available also). Send the hot fluid into these pipes to create a hot mass under the house (insulate over the top).

Then, drill a series of holes around the outside of this hot mass - these are for your recapture pipes. Send cool water through these and it returns warmed or hot.

The holes can be as deep as you can afford to drill (cheaper than excavating a pool). The thermal mass of earth / rock is well in excess of water, so you can store more heat and you don't have the damp issue.

Water may still bug you however - you need to watch for moving ground water - it will steal your heat. You would have to stop it somehow if it was on your site (eg a simple drain uphill from your site to divert groundwater flow).

This system is in production on quite a large scale (either in Canada or northern USA - haven't found the link again yet). In that case an entire housing estate sends its solar heated water into a massive ground thermal mass. By year 2 it's expected the earth plug of some hundreds of thousands of tonnes will be at about 80C.

It holds heat for years, provides hot water and home heating to the estate throughout winter, and best of all has been guaranteed 'free of ghoules, devils, witches, soul leaches and other blood-fermenting beasties' by a council of sundry ecumincal consulting ministers.

The success of that idea depends on the conductivity of the soil/rock below. Heat wants to go where it's cooler until the input rate of heat is greater than the conductivity. It would seem the larger the surface area as heat spreads out underground would enhance the flow AWAY from the structure. One would need to start warming Tibet before the heat would decide to make a U turn and return.

The idea of what is going to provoke that U turn is most interesting. I live on a granite base high in the Rockies with basically an uninsulated slab on grade. The slab stays a pretty constant 53 degrees F regardless, even with hot water circulated through it. Not insulating was a screw up and good thing, as the internal house temperature won't fall much below 53 no matter how cold it is.

The heat won't go down - thermodynamics will take care of that. If the top is insulated, it will spread sideways - hence your return holes around the perimeter of the hot plug. In any case, you seem to have a better handle on it than me so I suppose you've done your homework. But at least check out this link, as I reckon they have a better handle on it than you...http://www.dlsc.ca/how.htm

Thanks for that.

HI, Are you going to put any extra insulation between the liner and the retaining walls? (to avoid warming Tibet) Or is a decent rubber (EPDM?) liner enough?

Definitely, the outside of the foundation wall will have 4" of polyiso along with the entire bottom. The polyiso will sit on the smoothed ground, a protective liner on top, and then the actual liner.

Since the other floors will all be elevated also, the forming material will already be available for the elvevated slab above the resevoir.

Aeration of the water is very important, especially regarding close proximity to human habitation. Efficient aerators which provide "tiny bubbles" will serve you best, so far as aeration is concerned...(see Boyle's Law). An inexpensive injector, adding an appropriate amount of substance to defeat various "slimes" is important. Cyano-bacteria tends to cause algal blooming.

From standpoint of climate, you are in a location where too much humidity would not be an ambient problem. Alge is not usually a problem where you live. I like the weather in your part of New Mexico. I have lived in Santa Fe and Bernalillo.

I think it would be a good idea to periodically test the water in your reservoir. BOD is an important factor...(the oxygen demand of the collected water). Learning about this is not very time consuming. There are certain plants which can be added to your system to help keep a home-healthy environment...(biological water treatments using plants is a known value). Some unique homes around Lake Travis, near Austin, Texas, even have total water recycling systems which use horticultural filtration.

Zeolite filters, larger versions of the filters used in fish tanks and aquariums, are helpful, but cost may be an interruption in this case. Fact is, you can make your own filters using zeolite, and the zeolite which could be most helpful is located in Truth or Consequences, New Mexico. (St. Cloud Mining Company). A link to their place is on my home page, www.tridentworld.org.

Sounds like you are involved in an interesting project. Thanks for sharing. I hope these comments prove helpful. jw

To avoid growth of organisms in the water you need to follow standard procedures for swimming pool maintenance. PH balance and a simple ozone generator made from an ultraviolet lamp within a housing that allows air from a compressor or blower to flow past the UV lamp. Simply inject the treated air into the water after the water pump. Commercial ozone production and injection units are available if you don't wish to build your own. 5 CFM of treated air at a pressure above the water pump pressure should be more than sufficient. You can use an interval timer to periodically treat the water and experiment to determine the most cost effective timing.

Years ago, I built a home in Chicago that reduced energy use by 92% through an indoor swimming pool formed by a modified foundation with a precast concrete floor above the pool. 50% of the excess energy from the summer months was recaptured for winter use. The entire system worked very well.

Thank you for the simple solution. Because the water itself does not circulate, sending the ozonated air through a fine bubble dispersion directly into the water from the bottom seems fine.

To maximize the heat transfer from the copper piping to the water I believe that as long as the piping is near the bottom, the densest coolest water, the warmth will induce a convective loop expanding upwards and keeping the coolest water moving to the pipe.

The concrete slab above, a dividing concrete foundation wall down the middle of the structure (east west) and the concrete walls should provide plenty of conductivity to permeate the entire internal mass to an equilibrium radiator.

I still think you need some form of water circulation in the storage tank. Once the water is up to 90 degrees what will cause it to circulate? Since you live in the land of sunshine 360 days a year why not a solar operated pump. It does not need to be a big pump just enough to stop stratification.

I had a house west of Rio Rancho with solar hot water and heat. My large heat sump of water under the house ended up being dry salt(NaCl) for heat storage because of all the problem I had from growth of nasty stuff that smelled. I did not design in easy access to the sump so I end up putting a hole in the slab to get it fixed.
I originally used copper pipe. When I moved it was all black plastic pipe which doesn't transfer heat near as well. This well was 6ft deep by 10ft by 10ft. It was definitely large enough to last thru the few cold no sun days in Rio Rancho.

Seems like not doing anything with your water was the problem. In this case, to prevent freezing, a propylene glycol will be used circulating through the solar collectors and then copper pipe immersed in the water will transfer the heat.

One wants to calculate the Reynold's number in ensure the gycol flow is turbulent. However the gylcol decreases the Reynold's number.

Does anyone have a good link for data on various gycol water mixtures to do the Reynold's number calculation??

Sounds like you've decided beforehand that the simple aeration system is what you'll be installing. Please report back here your experiences after you have the system up and running. My experience tells me that you'll have quite the eye-opener.

I deal with contained bodies of water (several hundred to thousands of gallons) every day in industrial settings and it gets quite challenging to minimize growth and smell; you can't eliminate it. Water in almost any form is the most natural environment for organisms to grow (and smell) and nature finds a way to let them .

I don't doubt what you're saying in the slightest. What did your water do before it got stored?

Maybe letting rain water in with who knows what pollens etc in it isn't such a good idea. Water is definitely an uncanny equalizer.

One time cycling through New Zealand I was astonished at the galvanized tanks they had to collect roof water. The moss was inches thick in them. I suspect the oxygen from photosynthesis submerged in the water helped alot. That was the purest tasting water I've ever had.

One little microbe could change everything. If the water remains sealed the ozone injection seems like it has a track record. Under that circumstance there wouldn't really be anything to filter.

The amount of water I'm planning is 46,000 gallons.

Four feet of water is equivalent to about 16 feet of earth based on 62.4 btus per cubic foot for water and about 15 for soil. Since concrete weighs 145 pcf and holds 22.2 btus/cf I figure soil at about 100 pcf would be about 15.

Since equipment is already necessary to excavate for footings, why not use a loader and bring everything down to footing bottom level. The water also helps counteract soil pressure so every little bit helps.

The joy of life is experimenting to see what happens. I like being too dumb to know it can't be done and then solving countless problems as they arrive. Sometimes a solution isn't discernible until everything's broken.

Thanks for all the input.

I hope this isn't done cause I'm always ready to turn on a dime.

In the machine that is most similar to what you've described (heated), the water is used for high pressure water deburring and cleaning of diesel fuel injector before entering a clean room for assembly. The water is exchanged through a skimmer and filter once every couple of minutes and makeup is R.O. water with a very small percentage (1/4%) of rust inhibitor. In all of our applications, it takes only a matter of days of being idle to begin getting stagnant.

I'm just making a guess as to what may be happening with your situation.

I'm also too inexperienced to know what R.O. water is.

The word "idle" makes some associations. The water will be "settling" out with different densities finding their homogeneous layers. As the idle water loses its air content, the solution will go from aerobic to anaerobic. That will usually generate a smell. The rust inhibitor may end on top and being exposed to air, release it's odor but in full concentration because it's surface area is so large, the entire tank, but every thin but anything more than a molecule is still a saturated exposure.

Maybe if when the water enters the tank, the more turbulent flow it has, the more the tank will stay mixed, taking longer to stratify. Or, maybe it would stratify faster.

Maybe there's something to trigger an association which will solve your problem. Good luck and thanks for your input.

R.O. - reverse osmosis. Actually, its our customers problem . Good luck yourself!

PH balance and ozone in a sealed system works quite well. After 3 years of operation, the pool heat-sink was evaluated by scientists from Fermi Lab, Argonne National Lab, and Illinois Institute of Technology at the request of NBC television before the filming of a television special on the technology. No odors or growth. In fact, air from the house was later bubbled through the pool to eliminate odors and dust particles. A simple water filter was added to remove oxidized matter. The resultant air quality was excellent.

Legionella?

out of curiosity sake, do you have a internet link that has more details?

Regarding your request for a site address. Holisticstructures.com is the under-construction website for a startup corporation which will be making available various construction and energy technologies following a series of joint-ventures which are in the works. Pictures of the indoor pool which was previously mentioned should be on the site. Technical information for do-it-yourself projects is planned to be included on the site in the near future.