Open-loop geothermal - well problems LONG POST

I have a new house with an open-loop geothermal system. The house is two- storey with two heat pumps; a 5 ton unit for the first floor, basement and crawlspace and a 3 ton unit for the second floor. Used since last fall. Got great heat in winter with no red lights for the auxiliary heat, even on coldest windy nights (-35 degrees Celsius). Cools even better in recent heat wave (35 degrees Celcius). I am in Winnipeg, Canada where it gets pretty cold but only gets very hot for a few weeks.
I have two problems, perhaps partly related.
Most serious is that the injection well was overflowing by the end of winter. Normal static level is about 25 feet down casing with about 8 foot rise when both units are running. When it overflowed I could see that there were a lot of bubbles, more than a pot at full boil.
My pump rate is 21 USgpm.
The bubbles were caused by pressure reducing valves (PRV's) that were installed downstream of each unit. When I cranked the PRV's wide open the bubbles stopped and then came back when I reset the PRV's. I did this several times and definitely isolated the bubbles to the PRV's.
I was told that the PRV's were necessary because the installers adjusted the flow rate through each unit to limit the leaving water temp to 38 degrees F so that there would be no risk of freezing the exchangers. This seems exactly incorrect to me since slowing down the flow would allow the unit to draw more heat from each gallon of water and thus reduce the leaving water temp. To prevent freezing you should speed up the flow so each gallon gives up less heat and the leaving water temp would be higher.
The bubbles air locked the well, at least part of the problem was solved by installing a pump down the injection well and pumping out for a while. Then going back to the main house pump in injection mode. A lot or air was discharged, quite violently, from the well. A few cycles of this and I solved most of the problem - the mound up is 2 or 3 feet higher than last summer.
I don't know if the remainder of the capacity loss is more air in the formation that I can't get out or possibly calcium or iron precititation partially plugging the limestone formation. I acid treated these wells after they were installed and that really increased the capacity so I can always do that again.
The wells are both open holes in limestone formations, no screens at all. Sometimes I get a small amount of sand plugging the filter in the basement but not much - about a tablespoon of sand once every 3 to 6 months. When I get the sand I just run the main pump on high to a pipe to the river for a few hours and the sand goes away for a few months. I may have to borrow a larger pump so I can over-pump the well to get rid of more of the sand. It's not the main problem anyway.
My biggest problem is iron bacteria infection. I have been getting red slime on the filter to the extent that I have to clean it every 2 to 4 weeks. I have also learned that the bubbles could have caused both iron and calcium to precipitate out of solution. The water tested high for calcium hardness and maxed the iron bacteria colony counts.
I have researched well disinfection both from local experts and internet googling. I learned that the infection usually comes back. I figure that is because the methods used for domestic water wells are not adequate, or more accurately not enough, for geothermal open-loops. Since we have been pumping for a year now the bacteria has been spread through the limestone formation between the wells. Testing shows a 4-inch drop at one well when pumping the other well and discharging to ground. This is a good dis- connection from the point of view of geothermal heating or cooling but any connection at all will lead to spreading the infection. So I figure that the reason the infections always return may be that you have to disinfect the whole flow path between the wells to get all of the bacteria. If you just disinfect each well then as soon as you go back to normal operation you will suck the bacteria that were out of range of the chlorine into the system and you are back at square one.
I am thinking of siphoning chlorine into the discharge pipe in the injection well for two weeks or so. This should get chlorine into the flow path between the wells and hopefully solve the problem once and for all. My concern is that I calculate the chlorine ampount as over $1500 for just 50 to 100 ppm, more for the higher concentrations.
Has anyone done any well disinfection? If so, was it successful and, if so, what did you do?
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Wow...
First off, here in Minnesota, if we talk about re-injection wells on a pump & dump system, the DNR folks start running around flailing their hands, slapping temples & tush like their crevice & cranium are on fire... then they stop & say something to the effect of " we don't allow that" Hence, I'm not too familiar with the systems.
Sound like your suffering from the effect best explained by... "It's easier to pull a chain than push one"
Reducing the flow through the GSHP's makes sense to control the reinject issues, & 38dF is a good temp to maintain as a minimum out. What are your in & out water temps? pressures?
If your flow rates are increased, you'll compound the issues with more water forced into the ground. If your opening the prv's & the bubbles disappear, why not leave them open? Your pumps may run a bit wild, but it might be solving your issues... short term.
The depth of your frost line in Winnipeg might be a source of your problems. Here in MN they talk of 48", but we've been setting footing at 5' as the last few years, we've been cold w/no snow. 75% of the septics in my home county froze out 3 years ago... If your dumping 38dF water into a casing & expecting it to siphon down through the lime stone, maybe a string of "heavy flow days" in the winter is starting to back up the casing & freezing when it rises above the frost line. Opening the prv's increases the flow of warmer water thawing the ice etc... just a theory of course. Would a heat trace down the output casing help? Possibly cycling on based on outdoor temp. or run time in heat mode. maybe with sensor in discharge pipe.
In Winnipeg, I have to imagine your ground water has to be coming up around 45dF year round, correct? @ that temp your cooling comes cheap, but in heat mode your only getting a 7dF delta T. ROT say's you should have a 15dF delta T across a GSHP @ 3-4 GPM per ton... Thus, you should be running twice that to cover a 7dF DT for 8 tons = 24-32 becomes 48-64... I'm scratching my head w/ your 21 gpm, unless your ground water is coming up much warmer (about 53dF min...), you need more flow, which your getting by opening the prv's.
As for dumping to the river to clear sand, that's what's allowed in MN. You can't dump directly to a lake, river, or pond, you have to dump no closer that 18" from the water... Go figure? My brother dumps 3-5 ton GSHP out a 4" PVC pipe on the rock retaining wall of the beach. He likes to tell the local inspectors it's the shower & laundry waste, & he often spends time showing them the real source... They don't like his sense of humor, but they can't find a reason to shut the system down.
We suffer from tons of iron in our area, & the snotty rust colored filters do need replacing quite often. But that sure beats the price of the propane option available... Magnesium makes for a nice black buildup as well.
As for chlorinating the wells, I'm at a loss. I'd advise against it, especially if you domestic water is coming from the same source as your GSHP feed, such as many I've worked with. The infections you talk about are something I've never heard of, but I'd want to be rid of. Is this a summer or winter thing? Would longer term dumping to the river lessen this? I doubt there's a water shortage in your area?
p.s. I once rode the bike to the Winnipeg folk festival, on to Banff, Coeur De Laine, Yellowstone, Black Hills & Home. Winnipeg to Medicine Hat in one day, Rapid City to St. Paul in another day... lots of low mile days in between. Took a month, & met the "now wife" with in a week of getting back. I'm still longing for a month off to ride the Great lakes perimeter, but she laughs & hands me the honeydew list...
Man oh Man, I really enjoyed the Beat Farmers, John Prine, the Cowboy Junkies, Corky & the Juicepigs...
sweet jane, i'm a happy enchilada and i think i'm gonna drown.
good luck geothermaljones st.paul,mn.

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Hand it back and say, "I'll see ya in a month". :-)
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I am top posting.....shoot me
Have you considered switching to a closed loop, and not having to deal with as many problems with your systems. I am not familiar with your geology or climate, but somewhat understanding in the operations of your equipment.
Rather than contemplating adding chemicals, and investing in extra equipment to improve your open loop (and it most likely not to solve all your issues); wouldn't it make more sence to change your loop configuration..............or is your lake suitable for a pond loop.

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I have very interesting proposal for you pull you pipe lines out of well if any now shove stick of delamite in to well "fire in hole" that will open the hole and you may get even the oil out of it. "You never can tell" on the other hand I would take Bobs advice Tony

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What?
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What in the hell language are you speaking? Are you "free-basing" or "speed-balling" or whatever the hell? Bubba

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wrote:

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Gave you something to think about

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I have a Waterfurance 072 spit system vertical loop, which has never worked. I'm not saving any money going Geo, You, will get alot of advice here on this group, just as I did. it's going to cost $$$$$$$$ $$$$ Regards and good luck, RT
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Thanks, guys, for your coments. I agree with all of you.
I'm stuck with the open-loop system because the house is on a riverbank that is clay so it is not that stable. A closed loop system, either horizontal or vertical, would be in danger of getting torn apart with the movements of the bank. Piping to the river would not be allowed because we are not allowed to discharge anything into our rivers up here.
The aquifer is not potable water because it is way too salty so I didn't even need to get a permit for the two wells, part of that was also related to not being a net user of water - changing the temp is OK as long as you don't use any water.
I have narrowed the capacity problem down to the bubbles caused by the PRV's. I'll have the installer remove the PRV's which will prevent the problem from re-occurring. Then I'll acid treat the injection well to get it's capacity back to normal. I did the acid treatment myself when the wells were originally drilled so I know how to do it and I'll only be out the cost of the acid.
I am a civil engineer specializing in water resources so doing the well work is not too tough. I also was the general contractor on the house so I am actually in charge of my own warranty work. The original heating contractor turned out to be a crook - stealing from us and everyone else in town - so I had to fire him after he had drilled the wells but had not yet installed the well pump or heat pumps. Only got robbed of about $2500 which was actually good for the horror stories this guy left behind when he ran out of town. I then contracted with a great geo company to install the heat pumps and finish the ducting, etc but they didn't want any part of the well work this guy had started so I am responsible for that portion myself.
My real problem is disinfecting the wells in a way that will solve the problem once and for all. My best idea is to first disinfect both wells in the usual fashion and then inject chlorine into the discharge line for about 2 weeks. My theory is that the chlorine will follow the flow path through the limestone formation and kill all of the iron bacteria so it won't come back. That takes quite a bit of chlorine which I estimate to cost at least $1500 but could be double or triple depending on how high a concentration I need to use. I was hoping someone here had some experience chlorinating open-loop geothermal wells which is quite different from simple domestic water supply wells. With a domestic well chlorine costs from $2 to $6 if you want to go overboard. I need at least 1,000 gallons of Javex to get enough chlorine for the minimum chlorine concentration and I am not sure if the minimum will accomplish anything at all.
Questions I have are what concentrations have worked for others. Chlorine is less effective at cooler temps which is just what I have underground. Also, my PH is just at the max for best chlorine effectiveness and reducing PH with acid would help. Bit risky as mixing chlorine with acid can result in dangerous gases but I have all the safety equipment and it doesn't take much acid to lower PH.
Soner or later I'll get this system debugged. Last winter the system delivered all the heat we needed. In the middle of 40 below nights with very high winds I got up several times to see if the auxiliary heat had cut in and it hadn't. So the heat pumps were delivering well above their design capacity. This past month we have had 35 degree Celcius heat waves and the house was simple to cool. I used R20 walls, R60 ceilings, triple pane windows with all the E features and R2000 level sealing so the house is very energy efficient. The heat pumps are ClimateMasters with multi- stage scroll compressors which are about as high efficient as it gets. It is a 5,000 square feet house and we are using about $3,300 all up for electricity for a year - heating, cooling, hot tub, 4 computers, 2 ovens, pretty much all the toys. I figure the geo is worth the hassles.
I just need to solve the iron bacteria problem. If I had a bit of guidance on the concentrations it would be a great help. Spending that much money on chlorine is bad enough but if I try to save money by going light on the concentration then I just waste all of it. Going too high if unecessary, costs $1,000 to $3,000 extra so guessing is nervewracking.
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Did they install the PVR's on the outlet or inlet of the pumps? The inlet side of the pumps will cause massive cavitation. Better to use a variable speed pump and adjust it to the proper GPM

Adjusting flow rate are for several reasons. To maintain refrigerant pressures withing design conditions, too much water and your refrigeration pressures go too high or too low for their designed conditions. The flow rate is determined by water temp and capacity of the unit. Flow rate adjustment is also important to help prevent deposit formation and to help prevent errosion of the exchanger. If you have too many gpms in the summer you may experience possible icing on the air side evap coil due to the capacity of the compressor becoming much greater in BTU's than what your evap and CFM 's are capable of removing, this is expecially true with an FCCV or Cap tube system. You can also experience short cycling due to low inside evaporator pressures. The isntallers were correct but its not icing on the water side but the air evaporator side. In Heating mode the air discharge temps on the air side could be increased with more GPM's but it could be at a cost, errosion and compressor stress.
If you have even seen a geo with Penn water valves that are oversized you would immediatly know what I'm speaking of, and you don't want that problem.
This

Variable speed pump may solve this. Also, put a restriction on the outlet side of the tube running into the receiving well, it doesn't have to be a big restriction. This will help with the bubbles. Make sure you prove your gpms. The water coming out of the restriction at the end of the pipe would normally cause bubbles, but when its at the 25 ft depth it usually does not due to the pressure at 25 feet. What happening now is your creating bubbles due to lack of pressure at the PVR, lets say 25PSI to atmosphere, which agravates the bubble situation, restriction at the 25 depth limits the amount of pressure difference.
PLEASE LET US KNOW IF THIS WORKS, I need the information for my book.

Have you considered going deeper on your well and finding two aquafers, one on top of the other? With this system you would pump from the bottom and return on the top. This is done quite extensively in Virginia. But with limestone you must have a deep well.
BTW, capacity lose in your unit will probably happen soon due to scale build up. Bacteria is happening due to oxygenization of the water, cant get away from it. You can use an ozone generator made for water but its not cheap to purchase.

Yes, eventually your well will dry up due to plugging of the system with all this bacteria building up.
I would suggest two things. First, you mention that you cant put a loop in due to shifting of the banks. But your home is on this property, aren't you afraid of it slidding into the river? I'm sure you can put your horizontal loop somewhere. Loop material is tougher than you think, what about your water lines undergroud etc.
Go vertical, your well is vertical, It will cost a lot of money for 8 tons but, heck, no offence, your an engineer...
Lastly, if your not in a very populated area put the darn thing in the river. First try to explain to the jerks who are incharge that you are NOT discharging into the river anything that didn't come out of it. Tell them you will actually help it by oxygenating it and you will have the water filtered, thus its going back CLEANER than what you took out! If they say no, wait until there is a shift in power and do it underground and thumb your nose at them. Its obvious their idiots so you play the "I didn't know' argument if something develops. Of course, you best check out what the penalties are, in Canada you may have to be castrated for such an offence~
Keep in touch
This is a good dis-

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THANK-YOU VERY MUCH, GEOMAN !!! I do believe I've got it!
All of the points you made were great; I've done most of them.
You made a super comment which twigged my mind to the solution I was over- looking all along. You suggested an ozone generator which I had not thought of. I am afraid of using ozone because it makes bubbles which will air-lock my well again. BUT it made me think of salt water chlorine generators - same thing only different. I have been researching them for a swim-in-place pool I made in the basement but haven't finished yet. I did my own design and had the thing poured by the foundation contractor when we did the basement. I haven't finished my pump system design and want to use a chlorine generator instead of dumping in chemicals - supposed to be a different chlorine ion which doesn't smell or irritate eyes, etc. Anyway our groundwater has a high salt content, more than enough for the generators. I was going to use well water for the pool and call it a salt water spa. It works great in the hot tub. Anyhow - chlorine generation will let me get a continuous source of chlorine for free, after the cost of the equipment. The well work can make do with a simpler generator because it doesn't need sensors to turn it on or off. It will run whenever the well pump is running. It can be run forever to keep any new bacteria from multiplying. I just need to find out what concentration these things crank out. Hope I don't have to get a massive one. I estimate the chlorine to cost from $1500 to maybe $4500 and the fancy chlorine generator for the pool is only $1500 with all the bells and whistles. I saw a cheap one advertised for $269 - it the thing made a high enough concentration and lasted a few weeks I would be done and money ahead. Only one question I need to research - do these things make bubbles, too? I'll try my Yahoo pool users group.
Would you know if I should run the chlorine through the heat pumps or plumb it in downstream? I thinking downstream so I don't corrode the expensive bits if I over-do the chlorine to kill the bacteria. Might be nice to clean out the equipment and keep it clean. Maybe plumb it in a parallel fashion so I can skip the heat pumps for the initial high concentration phase and then dial down the chlorine and run it through the heat pumps to keep them clean. Would the chlorine yield any benefits such as scale reduction? My water coils are cupro-nickel because of the salty water. Don't know how that relates to chlorine though.

PRV's are on the outlet side of the heat pumps. They cause massive cavitation there, too. BTW, cavitation is not the correct engineering term. Cavitation refers to velocities much higher than in geo systems and it leads to erosion of strong metals. What we have is release of dissolved air and/or carbon dioxide due to the low pressures in the valves. Pressure and velocity are inversely related - if one rises the other drops. So a large increase in one leads to a large decrease in the other. Also, pressure is related to velocity squared so high velocities can quickly lead to very low pressures.

This is great to know because I really like and respect the installers and am happy to know they were on the right track all along. They gave me a high level of confidence in their work and now you have helped me get back to that good feeling. I'll pass this on to them, if you do't mind.

I had 75 feet of discharge pipe to start (50 feet below static water level) and figured the depth might limit bubble formation, and maybe it did limit new bubbles from forming at the end of the discharge pipe but it did nothing for the many bubbles formed by the PRV's. Even back pressuring with a smaller discharge pipe did not stop the extreme hissing and bubbling from the PRV's. Maybe a liitle but barely noticeable.
I do have a variable speed pump - Grundfos 22SQE07-160 to be exact. Also, I have the C301 controller for this pump. My geotechnical engineer friend has also recommended a restriction on the end of the discharge pipe. He has added restrictions to a lot of client wells and it has solved their air- locking problems. I am using a slightly different variation - instead of a restrictor orifice I am using a long piece of down-sized pipe. The small pipe will cause the same restriction as an orifice ( I pick size and length that way) by friction loss but it has a larger flow area and therefore lower velocities and less chance of bubbles. Same pressure change just a different method.
I have added a 50 foot piece of 3/4 inch pipe, replaces 75 feet of 1.5 inch. This does pressurize the system a lot better and lets me run the pump a bit slower. I am re-computing my system head curves more accurately than I had before to get a better handle on the exact discharge pipe size and length. I had actually sized my system for a smaller Grundfos pump than the one I have and I don't remember why I have the larger one - probably a problem with supply and I was in too much of a hurry to wait for the other one - rings a bell. My new computations show that I have been getting around 27 to 30 gpm compared to the manufacturers recommended 21 gpm - before my 3/4 inch pipe but with the PRV's.
The Grunfos controller has a lot of great features but it has one hassle for me. It shows the current draw, in watts, for the well pump plus speed, temp, pressure, etc. I was running 1300 watts all winter with the PRV's and when I opened them up and added my 3/4 inch pipe I found that I could get all the flow I needed at 650 watts ro so. Trouble is the shut-off pressure at that speed is only 27 psi. The Grundfos controller has a lowest setting of 40 psi so I can't set it low enough to shut off the pump when both heat pumps have shut their valves. The pump has a regular speed of 10,700 rpm (this is a 3-inch diameter pump) and I can slow it to 9400 rpm and run about 850 watts which is a significant improvement. I want to add more restriction to the discharge pipe which should back pressure the system enough to slow down the pump flows some more - still too high for the 50 foot 3/4 inch. I think a 100 foot of 3/4 inch should do it but I haven't finished my computing yet. I should end up with the 21 gpm flows at 9400 rpm and hopefully less than 800 watts. The controller shows the instantaneous power draw as well as the total power used by the pump since new - like a car odometer, it can't be reset. The well pump didn't use a lot of power even at the 1300 watts all year. I really like the Grundfos controller except for the minimum shut off setting issue. I guess they make it for domestic water supply where that would be perfect. Also, you have to pay extra for a remote control which is the only way to set or change anything except for the shut off setting. If I loose or break the controller I won't be able to reset anything at all. Also, there is a wide strip wire inside the unit which blocks the infra-red signal so I have to leave the cover semi-open to use the remote. Pretty dumb for german engineering.

supply well is 340 feet deep and the discharge well is 160 feet deep. The limestone is so tight I had 50 feet of drawdown when the wells were first finished. I acid treated the wells and got it down to 5 feet. I suppose I could do another super acid treatment and improve the well capacity enough to use it in a double acquifer fashion. trouble is there is only one acquifer, unless you count the torturous pathway through the rocks as some degree of separation. It may well be sufficiently separated that way to allow for significant heat recovery in whatever percentage of the water that gets double pumped.

Thanks again - this ozone tip helps me a lot. Do you know what sort of on- going maintenance I should be doing to prevent or limit or fix scaling? I have a tee end that I can use to add chemicals to the flow. Have tees at the main well line in the house and upstream of each heat pump. When the PRV's are removed I will replace them with tees so I can add something downstream of each heat pump as well.

The house in the city on one of the nice old neighbourhood streets. My wife grew up a few blocks away. The house is 300 feet from the riverbank and the danger area for sliding is only about 100 to 150 feet from the river. The house water is city system and the sewer and electrical all are buried from the front of house away from the riverbank. The front yard is only 75 x 95 feet and has over a dozen giant old oak trees. There is no way to snake the connections for a vertical system without destroying most of the tree roots. Around here we love our old oaks. Besides much of the yard is driveway and being cleared of snow all winter the frost gets about 8 feet deep. You can't make all the vertical loop connections that far below ground and it makes no sense to me to bring heat up from 50 feet below ground and then route it through the frost zone to the house.
The backyard is on the riverbank and to snake a few thousand feet of horizontal loop or vertical loop pipes would take the system too close to the river and into the slip zone. The banks here are clay which moves very slightly, just enough to tear up piping. All the neighbors have lawn irrigation from the river and the ones which are buried are constantly leaking from breaks due to small movements. They only break near the river so some guys have switched to above ground pipes for the first 150 feet.
Closed loops would have to circulate some form of anti-freeze and if that leaked it would kill all the nice oaks in the backyard not to mention a fine for a chemical spill.

Our feds have a relatively new law where you can't discharge nothing no-how and if you do they can fine you $350,000 for a residence first offence. It's more for commercial guys. I don't think they have tried it yet but I don't want to be the first. I have to deal with them for all of my design projects and it is a huge hassle every time.
I did actually give a lot of thought to using river water; it may even cost a bit less than loops. Problem is the river is held up about 10 feet in the summer by a bunch of stop logs way downstream of the city. They remove these stop logs in the fall so the river will not be restricted in the spring floods. When they take out the logs I have about 50 feet of mud exposed to the edge of the ice. A river pipe system would have to be buried about 8 ft below this mud to prevent freezing. That is not too bad as my buddy has a horizontal directional drill rig; he did my well connections. Trouble is some sort of intake structure would be required that would stand up to ice floes in the spring. God help me if some drunk motor boater hits it in the summer when it is more than 50 feet from shore. My boat ramp gets silted full every spring when the river is high for a few weeks and I think an intake manhole or whatever could turn into a solid mud mess in no time. Then there is the issue of the winter low flow channel moving from year to year - it could end up 400 feet from my side of the bank some years. I'd end up with a system that plugged with mud all the time, got wrecked by the ice every spring and then I'd get sued every time some jerk killed himself on the intake structure. I'm better off fixing my wells.
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I just checked into the salt generators and they won't work for disinfection of the well for two reasons;
- my well water is below the minimum salt concentration these units need
- the units don't crank out enough chlorine to get my minimum 50 ppm concentration, even if the groundwater had enough salt.
In order to make this work I would have to inject salt ahead of the generator and/or lower the pump speed so lower amount of chlorine would yield a higher concentration but the flow would have to be about 1/8 th of the present pump flow. Not doable.
Back to square one.
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If considering Chlorine I think you would be better to check out a source for powdered Chlorine. Though from Canada we have a place in Mexico and the powdered chlorine I use there is probably 10 times the strength of bleach, maybe stronger about 2 ounces a day maintains the strength for a 4x5x1.5 meter pool.
I was considering Geothermal for airconditioning, with all of 1 supplier 1000 kilometers distant, initial suggestion was for a open well system consisting of 3 wells, one to provide the water and two for returning to ground. Location being a beach area the well water is very salty virtually seawater so we had been re-considering a closed well system.
Unfortunately well drilling is expensive here, 1/10 the price where the re-seller is, Geothermal units are also expensive and restricted to 1 year warranty. We can buy split air conditioners for 10% of even older Geothermal, WaterPump.com versatec units even without considering the wells. These are for the older refrigerant types which will be phased out about 2010. We may simply have to go with split air conditioners and perhaps convert in 5 or so years by which time the technology may have reduced in price.
I still wonder about reality of Salt Water Chlorine Generators. In Science passing a current through water created electrolysis which caused Hydrogen and Oxygen to separate into gasses. The table salt normally becomes ions of Sodium and Chloride while disolved - what is the generator really doing.
I know a pool of salt water will discourage growth of Algae for several days and if its circulated how would that differ from the ocean.
Simple question if anyone has the chemical equation answer to how these generators are supposed to produce chlorine.
Last question would be what of the possibility of closed loop, loops in the river
k snipped-for-privacy@hotmail.com www.playalindahotel.com
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I had settled on the generators for our swim-in-place pool in the basement until I read an article stating that chlorine was the same no matter how it was obtained; chemicals or generators. That makes me wonder why they say it doesn't smell or make your eyes red. Now your comment about the oxygen and hydrogen rings a bell. Would the generators make explosive levels of hydrogen? I, too, would like to see someone explain the chemistry.
As to you question about closed loops in the river - that would be a great idea and more efficient than ground burial if the river doesn't freeze like thye do up here. The closed loop in the river would be much cheaper than ground burial and it would avoid a lot of hassles that the ground systems can have. In any closed loop system it is necessary to ensure a competent thermal surround for all of the piping. In vertical loops they use a thermal grout, at least they are supposed to. Around here they claim it is not necessary and the customers are getting a lot lower efficiency than they paid for. Horizontal loops can be even worse if they are bedded in sand which is common to create a smooth support for the pipes. If there is no groundwater to saturate the sand then the thermal efficiency is very low.
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andrew collins had written this in response to http://www.thestuccocompany.com/hvac/Re-Open-loop-geothermal-well-problems-LONG-POST-24667-.htm : Reinhard
We are consulting engineers in NYC. We have the same iron bacteria problem at a building in Queens NY. Orange mucous everywhere. While the system works, we are currently having pressure gauges isntalled, and a UV filter, with the idea of decreasing the bacterial colony by death due to sunburn. This was a solution suggested by the geotech. The real problem is the genration of oxygen due to changes in pressure as the systems pump water around. There is no mucous in the supply well, only in the 2 diffusion wells.
This is a public project and I do not know if the installation is complete yet. Post back if you are interested
------------------------------------- Reinhard wrote:

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