Posted by zero on October 23, 2008, 11:35 pm
>We built our new house have been in for 2 years now and our geothermal
>heating sytem is paying off - starting third winter now. The house is
>5,000 sq ft on 2 floors plus a finished basement with a walkout so we are
>servicing 7,500 sq ft. Our electric bills have been about $300 to
>$350/month, about $3,900/year. We have every electrical appliance and toy
>imagined plus a hot tub on the deck which is used year round. We are in
>Winnipeg, Manitoba which is pretty cold. Or electric utility, Manitoba
>Hydro, has a web site with an energy calculator that showed our heating
>costs would have been $4,000/year with gas and $2,000/year with
>geothermal and this seems approximately correct with our experience. We
>are on track for a 10 year payback. However, that doesn't count all the
>time I have spent battling air locks in the injection well plus
>chlorinating and acid treating the wells - apply my professional charge
>out rate to my time off work and we are losing $5,000/year to the
>hassles. The choice of open-loop is the killer error we made - it is a
>huge horror story. even the choice of a crook for a contractor was minor
>compared to chosing open-loop.
>Would I do it again? Yes because I can now design and inspect these
>systems, especially with the advantage of hindsight and hands-on
>experience. Would I recommend it to someone else? No way - because there
>are so many pitfalls that I wouldn't want to be involved.
>We have a 3-ton unit for the second floor and a 5-ton unit for the first
>floor, basement and crawlspace under the basement structural floor. They
>are ClimateMaster Tranquility 27 units with an open-loop. The auxiliary
>heat has never come on even on minus 38 degree Centigrade nights with a
>howling wind.
>The heat pumps work well but the open-loop is a collosal pain in the
>butt. The wells are infested with iron bacteria which requires cleaning
>the filter every few weeks - takes me 5 minutes. The injection well has
>air-locked twice now - first time after 2 months of use and the second
>time after 10 months. I have re-designed the injection well pipe system 3
>times now to try and improve the air locking situation. Gets better each
>time, next time ought to do it.
>I do NOT recommend an open-loop and consider it a huge mistake. A closed
>loop would have avoided a lot of on-going troubles. Humans have been
>getting water out of wells for thousands of years and we know how.
>Injecting water down a well is a new trick that has many variables
>frustrating the effort and is a real trial and error process.
>The injection well overflows when it gets air locked. It is a good thig
>our property is large enough to contain the overflow - for 4 months the
>first time. Had it overflowed towards a neighbors house we would have had
>to either switch to the electric auxiliary heaters or try and fix it in
>mid-winter. The solution was to pull out the discharge pipes and drop in
>a well pump to reverse the flow and get the air to come out. That is
>almost impossible in 30 below weather - things would freeze up
>constantly. In many locations there is nowhere to pump to - can't pump to
>a sewer for the 3 days it took before the air finally let go. The second
>time the air lock was caused by very small bubbles which travelled
>farther into the limestone formations and thus wouldn't let go until I
>pumped for a week at double the usual rate. Good thing I could pump onto
>our own property! The concern with air locking is that the reason air
>comes out of solution with the groundwater, pressure drops, also cause
>calcium and other minerals to also come out of solution. These deposits
>block the limestone formations and reduce well capacity. The solution is
>to pump industrial strength acid into the formations to eat out the
>fracture zones. Works good but causes a huge gieser of foam, gasses, air,
>water and acid by-product. I aimed it at the lawn but where would a
>normal resident direct such discharges? You would need a tank truck to
>help at considerable cost. These are just a few of the basics of open
>loop hassles and costs - they will go on forever - all I can do is re-
>design the entire piping system and try to run the system at a higher
>pressure which will reduce the tendency to air lock and deposit minerals.
>My research shows that well maintenance, by acid treatment, is always
>required for all injection wells - nobody told me at the beginning. The
>only question is can I get it from yearly to maybe every 5 years? Note
>that the best geothermal firm in town designed and installed this sytem -
>the equipment and pipe sizes they chose all need to be redesigned at my
>cost. "This is the way we always do it and it works the rest ot the
>time."
>However, closed loop systems require careful design as to layout, type of
>pipe, depth of bury, and most critically, soil moisture (for horizontal
>loops). Dry soil does not transfer heat very well - wet soils are great
>for heat transfer but terrible to work in for the installation. Dry sand
>has air in it which is an insulator and thus impedes heat transfer and
>reduces the efficiency or capacity of the collector field. Most
>installers use sand backfill to protect the pipes from crushing by clods
>of earth. If the groundwater is below the trench the sand will dry out
>and the field will not transfer enough heat unless it has been designed
>and sized for dry sand. Some guys will design for the damp clay
>surrounding the trench full of dry sand. Backfilling with thermal grout
>makes the installation efficient but more expensive.
>Vertical loops are better but require a lot of connections all of which
>are prone to leakage if not done right. Also, vertical loops use 50 ft
>deep holes, or deeper, but the connecting pipes are typically installed
>only 3 feet down which is within the 6 to 8 foot deep frost zone around
>here. So a lot of the heat brought up from the depths is lost enroute to
>the house - nobody will insulate the collector pipes. I went through this
>with several of the bidders on our system.
>My experience is that the geothermal industry is over-loaded with get
>rich quick artists with little technical competence and less ethics. The
>capital costs are in no way warranted by what are essentially simple and
>cheap systems. I got several excellent references for my first HVAC guy
>but then he started demanding $10,000 advances before doing any work, he
>used the world's worst well driller for our wells and then the police and
>tax collectors showed up - police wanted to arrest him for taking 5
>figure deposits from other people and never doing any work and the tax
>guys wanted to garnishee anything we might ever have paid him. We fired
>him and got a new company that was pretty good but then it was a case of
>them not warranting anything the first guy did - logical. There are some
>good contractors, I think our second one is, but they are few and far
>between and tough to identify. I found as many good references for the
>crook as for the second company. The crook did just enough good honest
>work to get references for his real scam.
>There are guys installing horizontal loops only 3 feet down in our area
>(had one guy quote this)where the frost goes 6 to 8 feet down. Sure you
>can suck energy from frozen soil but the hit in efficiency is significant
>and prevents re-couping the investment. We have friends with geothermal
>heating, open loop, who are paying more for heating than they did with
>their old natural gas system. Geothermal thermostats have red indicator
>lights showing when the electrical auxiliary heat cuts in and the red
>lights are on most of the winter - so they essentially have an
>inefficient electric furnace. They were ripped off by an uneducated
>installer and incompetent well driller - their wells are very shallow,
>the same depth casings and very close together so the water simply short
>circuits - after a day or so they are re-pumping the same water and the
>flow path through the ground between wells is too short to pick up much
>heat. The geothermal heat pumps loose efficiency quickly with lowered
>temps for the incoming water. Since open loops are pumping water, not
>anti-freeze, there is a safety shut-off required to prevent cooling off
>the water so much that it freezes and bursts the heat exchangers. Thus
>their geo system often shuts down and reverts to electric - most of the
>time. The electric auxiliary heat is just a few cheap wire coils (looks
>like a 1960's portable heater) which are much less efficient than a
>modern electric furnace. Their contractor is out of business, or has a
>new name, and the well driller was only responsible for doing what he was
>told by the contractor so they are left with no recourse at all.
>Closed loop systems require a special thermal grout to achieve good heat
>transfer from the soil to the pipes but the suppliers I spoke with don't
>even import that stuff into our province despite several thousand systems
>having been installed. Vertical systems should have spacers between the
>pipes to locate them as close as possible to the hole walls and thus get
>the best heat transfer - I watched two installations at other houses and
>they not only didn't use spacers but taped the pipes together to make
>them easier to force down the hole. "We always do it that way" was the
>response to my question.
>In summary - geothermal works and the cost savings are there but the odds
>of getting ripped off and getting an inefficient system are very good -
>research the contractor more than the system. All the sytems work well if
>properly designed and installed, few of the contractors do. Don't go
>open-loop no matter what they tell you. Open-loops suffer from iron
>bacteria, calcium deposition within the pipes and heat exchangers, air
>locking causing the injection well to over-flow (try fixing that in the
>winter while water flows into your neighbor's yard and imagine how much
>you are going to get sued for if it reaches his house), poor well design,
>poor well drilling and lots of things that I forget right now or haven't
>happened to me, yet.
>The most irritating thing is that the initial costs are grossly inflated
>because it is a whatever the market will bear industry. Geo wells are
>simpler and cheaper to install than water wells but you get charged a lot
>more "because it is geothermal". Use only a firm that has been in
>business for many years - a lot of the companies around here are new or
>are changing their names every few years. The many poor installations are
>starting to pile up and when the warranty hassles get too much it is
>cheaper to kill the company than do the work. Many geothermal errors are
>very expensive to fix - a new well is $10,000 to $15,000 IF a drill rig
>can get into the site after the house is built, same sort of costs to fix
>closed loops. Double those costs for expensive landscaping that has to be
>torn up so repairing a geothermal system will cost over $20,000 and could
>hit $30,000 to $50,000. Well infections can never be cured, according to
>all my research and best efforts so that's a permanent problem. Note
>injection wells spread the infection throughout the groundwater formation
>so disinfection is not like a simple farm supply well where some Javex
>will do the trick. Drilling a new well doesn't help because the infection
>covers more than just your yard. The lack of talent in the industry
>causes so many of these problems that the small cheap companies can't fix
>the problems they cause.
>If you do go open-loop get at least 5.5 inch inside diameter casing. Case
>one well at least 25 feet deeper into the rock than the other (offset
>casing depths so at least one fracture zone is not common to both wells -
>lots of luck getting driller to actually do it, install a double pitless
>adaptor and double pipes into the house (both wells; you'll need them
>sooner or later), locate wells at least 250 feet apart (can trade this
>spacing for more vertical offset in casing depth if in limestone), get
>best well driller you can find and make sure he, and everyone who works
>on the well, disinfects after working - a bottle or two of Javex at the
>time by driller and installer would have saved us a permanent
>disinfection hassle. These are just some of the things required that you
>will get resistance on when you deal with contractors. Our first
>contractor, the crook, had the well driller install a 5 inch casing but
>with the double pitless adaptor there is not room for a standard 4-inch
>pump so we are forced into expensive 3-inch pumps that are much less
>efficient. The well driller knew standard pumps wouldn't fit but he was
>going to get paid before we tried to install the pump.
>If you go closed loop make sure they use thermal grout or, better yet,
>that the pipes are in wet soil all year round (near the septic field is
>very good, thermally, but not so great if you ever have to search for and
>repair a leak), bury pipes at least 6 feet and over-size the collector
>field or at least make contractor produce the calculation sheet and give
>you time to check it out.
>Either horizontal or closed loops require at least a hundred heat welded
>connections that MUST be leakproof. Now imagine a contractor paying
>minimum wage to his guys to do such finicky work in the dust and dirt -
>never mind if it rains and mud is smeared on everything. It only needs to
>pass a pressure check, done much less carefully if you are not watching,
>and not leak until the cheque clears. Only the very best firms are worth
>risking this sort of work with.
>Something else I learned the hard way - use only one heat pump! We have
>two heat pumps and many of the problems are due to use of two heat pumps
>on one open-loop. Dividing the supply flows is a root cause of huge
>problems and that would also be true for closed loops, maybe worse for
>closed loops. Flow splits require use of balancing valves which are
>actually pressure reducing valves (PRV's). They work by throttling down
>flows through each heat pump to balance the flows. The trouble is
>throttling flows causes gassing - that is the hissing sound these valves
>make - solid liquid does not hiss. All installers use PRV's to balance
>flows and the results are air locked wells or air locked closed loops.
>Much better to use a larger heat pump and design a zoned system for the
>house. All the bits are accessible and a bit of trial and error is
>simple. NEVER allow a PRV on a system, closed or open loop. Nothing but
>trouble. Size the pump for a bit more flow than needed and use a variable
>speed pump to adjust flows further. NEVER NEVER use a PRV!!!! A single
>variable speed supply pump and a single heat pump is simple and has the
>best odds of working with minimal hassles. PRV's guarantee trouble - I
>told my installers "no PRV's" but they insisted and said if they caused
>any trouble they would take them out. The next year when the well
>overflowed there were huge bubbles coming out the top which came and went
>when I opened or closed the PRV. So they removed the PRV's and replaced
>them with orifices at the ends of the discharge pipes which I wanted all
>along. Then they sent me a bill for $2,200 for "improvements at your
>request". Best I could do was negotiate that to half. Remember, PRV's
>hiss which is air or gas and that air/gas is going into your well or into
>hundreds of feet long closed loop pipes. How are you going to get the air
>out? Who is going to pay for fixing air locks? It won't be the guy who
>installed the PRV "because I use them all the time and they never did
>this before". Agravating thing is PRV's are NOT required as there are
>options which don't cause air locks.
>Fixing air problems in wells or pipe loops is as complicated as debugging
>a computer program with no end of possibilities and ways to deflect
>blame. It is a time consuming hassle and thus expensive to pay someone
>else to fix. Unless all the possible causes of air locking are found and
>corrected the problem will reccur and always at your expense. NO PRV's
>!!!
Thank you for taking the time to type all of the above info.
I'm not using any ground source heat pumps, but am researching
building such.
Again, thanks.
zero
>MoviePen@gmail.com wrote in news:80ce5022-78b5-44a9-9840-274b939ff6d4
>@m45g2000hsb.googlegroups.com:
>> I'm very strongly looking at converting our 3,300sqft home from oil to
>> geothermal. I'd love anyone who has installed geothermal in a
>> residential home (preferably converting from another heat source) in a
>> cold climate area (I'm in the upstate NY area) to share the following:
>>
>> -- anticipated and actual heating/utilities savings (or not)
>> -- the size (in tons) of your system
>> -- if you have an open or closed source
>> -- if you had to rely on backup heating
>> -- your rough location (so I can compare climate similarities or
>> differences)
>>
>> Right now, even with the high capital cost of installing a new
>> geothermal unit, I'm looking at an approximate 5- to 6-year payback on
>> this system. It's a very attractive proposition.
>>
>> Thanks!
Posted by John Gilmer on October 28, 2008, 11:38 am
Wow!
That's a very interesting and potentially very useful report.
Just some random comments/questions. Note that I don't have any
particular expertise so I may be asking "dumb" question or making foolish
comments. I beg forgiveness in advance.
When you have "air lock"problems and have to "dump" the water on the ground,
did you consider spraying the water into the air to generate a pile of
frozen "snow/ice?" When the outside air is below freezing, you can "warm"
the air somewhat.
Some rural folks consider "shocking" a drinking water well just normal PM.
Basically, they dump a few gallons of bleach down the well. Did you try
that?
Did anyone suggest/try "degassing" the dischanrge water before discharging?
Before leaving your home the water would enter an air over water tank with
an air pump that would keep the tank under a slightly reduced pressure.
Depending upon the details of your discharge well you might want a check
valve at the bottom.
Your neightbors who end up using resistance heat much of the time might
consider just running the ground source heat pump at whatever rate it can
maintain without risk of freezing. A variable speed blower in the air
handler can help. Rather than use the "strip heaters" in the air handler,
just get a few electric heaters with thermostats and run them where the
people are.
Keep in mind that all I have is a conventional air source heat pump. Our
system has 60 amps worth of "strip heaters" for auxilary heating and for
keeping the chill off when the outside unit goes into defrost mode. I
disconnected 40 amps worth (2 of the 3 "strips") by shifting the wiring so
that the fan and transformer are on the circuit with a single strip and the
other two strips are on a separate breaker. The house can get a little
cooler but the room heaters put the heat where we need it when watching TV,
etc. Were my heat pump to fail, I call always restore all my aux heat by
flipping the breaker back on.
We also have an LPG fired ventless heater in the family room. This room is
at the far end of the house and over an un-heated garage. I understand
that ventless units are illegal in many places and the fumes disturb some
folks but we have no problems (legal or health.)
We use a very experience and honest "HVAC guy." When I asked him about
grothermal, he just said: NO.
Posted by Michael B on October 28, 2008, 7:36 pm
> We use a very experience and honest "HVAC guy." When I asked him about
> geothermal, he just said: NO.
In every profession, a few professionals and a lot of amateurs.
Regardless
of their level of experience and honesty.
Posted by Reno on October 29, 2008, 12:27 pm
>
> When you have "air lock"problems and have to "dump" the water on the
> ground, did you consider spraying the water into the air to generate a
> pile of frozen "snow/ice?" When the outside air is below freezing,
> you can "warm" the air somewhat.
>
The first winter we were in the house the injection well overflowed by the
end of January. Our winter air temps are way too cold for normal water
pumping. I just allowed the overflow to go overland until it soaked into
the ground below the snow somewhere. I could have made snow but dealing
with water pipes and pumps in the winter is a lot of trouble. All pipes
must be drained within minutes of stopping the flow or they freeze up. I do
use the well pump once a winter to refill the hot tub but I pick nice sunny
afternoons with only about minus 5 degree Centigrade temps - happens a few
times each winter.
> Some rural folks consider "shocking" a drinking water well just
> normal PM. Basically, they dump a few gallons of bleach down the well.
> Did you try that?
>
Boy did I ever! the problem is that geothermal differs from normal farm
wells where they only pump out of a single well. Disinfection is easy
because the pump keeps the bacteria close to the well where the chlorine
can kill them. In geothermal two well systems there is some flow through
the groundwater formations between the wells. This is great from a heating
point of view because the water picks up heat as it travels. From an
infection viewpoint it is terrible because bacteria get spread throughout
the rock formations and the chlorine can't get at all of them so enough
remain to re-infect. I researched the heck oput of well disinfection and
then tried a program of shock chlorinating followed by injection of
chlorine into the discharge piping for a 2 week period. I used up 19
carboys (20 liter barrels) of industrial strength chlorine. The infection
returned within 3 months.
> Did anyone suggest/try "degassing" the dischanrge water before
> discharging? Before leaving your home the water would enter an air
> over water tank with an air pump that would keep the tank under a
> slightly reduced pressure. Depending upon the details of your
> discharge well you might want a check valve at the bottom.
>
The check valve is good thinking and I am using a variation of that - I
installed orifices on the ends of the discharge pipes to throttle the flows
down to the required rates for each heat pump. The idea was to maintain
high pressures within the pipe systems ro prevent gassing. It worked to the
extent that the well lasted 10 months instead of 2 months before
overflowing again. It created a worse problem in that the bubbles were now
very tiny and got carried farther into the rock formation which made it
very difficult to solve the airlock by reverse pumping. Bubbles got in the
rock far from the well are in zones where water is flowing very slowly
towards the well and so has little force to move the bubbles. I could only
restore about half the capacity by reverse pumping. I restored the full
capacity by acid treating the well. When the acid hits the limestone it
eats it up pretty good and causes a lot of by-product gasses to form very
violently. This causes a very violent gieser to erupt from the well top
which I control with a well seal and vent pipe leading to a safe area. The
gieser removed the rest of the air and combined with the acid eating the
formations into larger cracks restored well capacity to better than
original.
Your air over water tank suhgestion refers to air removal tanks which are
readily available but not suitable to geothermal applications. Ground water
contains dissolved air, gasses and minerals. I researched them, too. When
the pressure is reduced all three of these are released. This happens in
air removal tanks. The air removal would be great but the mineral
deposition would plug up the heat exchangers if the tank were upstream and
would plug the groundwater formations later.
The trick is to keep the system pressures as high as possible, avoid or
minimize pressure drops through all parts of the system and locate the
orifices as deep below the water surface as possible. Depth increases local
pressure and reduces gassing and mineral deposition. My problem is that I
can reduce air locking but not eliminate it. It is very frustrating that
reduction of gassing also results in smaller bubbles which eventually air
lock the formations but do it so far from the well that air removal is
almost impossible. I have solved 99% of the gassing but the remaining 1%
still causes air locking and makes it much more difficult to cure. The
choice was large bubbles airlocking in 2 months but solvable with minor
reverse pumping effort or tiny bubbles air locking ion a year or so but
requiring huge reverse pumping efforts plus acid treating to remove. The
acid is dangerous to handle and use. It is not a minor issue.
For my next trial I am comparing Plan C - upsize all of the pipes and the
pump pressure and increase the length of the discharge pipes to Plan D -
leave pipes as they are now and install some method of causing the tiny
bubbles to flow upward instead of downward. Plan D appeals because it will
get any bubbles that may occur out of the water. I am looking at putting
the two small discharge pipes within a larger pipe that has it's top above
water in the injection well. The orifices will stay at the bottom of the
discharge pipes so water will have to flow upward and then overflow the
larger pipe and drop gently into the well. I hope the bubbles will be
released above water. This plan may work better if I go back to the large
bubbles setup because large bubbles will separate from the water more
easily. It's a theory.
> Your neightbors who end up using resistance heat much of the time
> might consider just running the ground source heat pump at whatever
> rate it can maintain without risk of freezing. A variable speed
> blower in the air handler can help. Rather than use the "strip
> heaters" in the air handler, just get a few electric heaters with
> thermostats and run them where the people are.
>
Up here the minus 20 degree days are considered warm. We get Minus 30 most
nights and often colder yet. When it is this cold all rooms without a lot
of het are very cool. the problems are not just confort but also moisture
control. Cool walls allow for condensation which travels into the walls and
rots the house. If a room isn't warm enough we can get frost formation on
the walls or ceilings which would destroy the structures. We can allow some
rooms to be a few degrees cooler than others but we have to have
significant heat into all rooms. The outside temps just suck the heat out
of the houses.
Posted by Michael B on October 28, 2008, 7:33 pm
> However, closed loop systems require careful design as to layout, type of
> pipe, depth of bury, and most critically, soil moisture (for horizontal
> loops). Dry soil does not transfer heat very well - wet soils are great
> for heat transfer but terrible to work in for the installation.
Closed loop with a septic system leaching field over it could be
considered. Even a greywater delivery field could help make sure
thermal conductivity was maintained.
XML site map
>heating sytem is paying off - starting third winter now. The house is
>5,000 sq ft on 2 floors plus a finished basement with a walkout so we are
>servicing 7,500 sq ft. Our electric bills have been about $300 to
>$350/month, about $3,900/year. We have every electrical appliance and toy
>imagined plus a hot tub on the deck which is used year round. We are in
>Winnipeg, Manitoba which is pretty cold. Or electric utility, Manitoba
>Hydro, has a web site with an energy calculator that showed our heating
>costs would have been $4,000/year with gas and $2,000/year with
>geothermal and this seems approximately correct with our experience. We
>are on track for a 10 year payback. However, that doesn't count all the
>time I have spent battling air locks in the injection well plus
>chlorinating and acid treating the wells - apply my professional charge
>out rate to my time off work and we are losing $5,000/year to the
>hassles. The choice of open-loop is the killer error we made - it is a
>huge horror story. even the choice of a crook for a contractor was minor
>compared to chosing open-loop.
>Would I do it again? Yes because I can now design and inspect these
>systems, especially with the advantage of hindsight and hands-on
>experience. Would I recommend it to someone else? No way - because there
>are so many pitfalls that I wouldn't want to be involved.
>We have a 3-ton unit for the second floor and a 5-ton unit for the first
>floor, basement and crawlspace under the basement structural floor. They
>are ClimateMaster Tranquility 27 units with an open-loop. The auxiliary
>heat has never come on even on minus 38 degree Centigrade nights with a
>howling wind.
>The heat pumps work well but the open-loop is a collosal pain in the
>butt. The wells are infested with iron bacteria which requires cleaning
>the filter every few weeks - takes me 5 minutes. The injection well has
>air-locked twice now - first time after 2 months of use and the second
>time after 10 months. I have re-designed the injection well pipe system 3
>times now to try and improve the air locking situation. Gets better each
>time, next time ought to do it.
>I do NOT recommend an open-loop and consider it a huge mistake. A closed
>loop would have avoided a lot of on-going troubles. Humans have been
>getting water out of wells for thousands of years and we know how.
>Injecting water down a well is a new trick that has many variables
>frustrating the effort and is a real trial and error process.
>The injection well overflows when it gets air locked. It is a good thig
>our property is large enough to contain the overflow - for 4 months the
>first time. Had it overflowed towards a neighbors house we would have had
>to either switch to the electric auxiliary heaters or try and fix it in
>mid-winter. The solution was to pull out the discharge pipes and drop in
>a well pump to reverse the flow and get the air to come out. That is
>almost impossible in 30 below weather - things would freeze up
>constantly. In many locations there is nowhere to pump to - can't pump to
>a sewer for the 3 days it took before the air finally let go. The second
>time the air lock was caused by very small bubbles which travelled
>farther into the limestone formations and thus wouldn't let go until I
>pumped for a week at double the usual rate. Good thing I could pump onto
>our own property! The concern with air locking is that the reason air
>comes out of solution with the groundwater, pressure drops, also cause
>calcium and other minerals to also come out of solution. These deposits
>block the limestone formations and reduce well capacity. The solution is
>to pump industrial strength acid into the formations to eat out the
>fracture zones. Works good but causes a huge gieser of foam, gasses, air,
>water and acid by-product. I aimed it at the lawn but where would a
>normal resident direct such discharges? You would need a tank truck to
>help at considerable cost. These are just a few of the basics of open
>loop hassles and costs - they will go on forever - all I can do is re-
>design the entire piping system and try to run the system at a higher
>pressure which will reduce the tendency to air lock and deposit minerals.
>My research shows that well maintenance, by acid treatment, is always
>required for all injection wells - nobody told me at the beginning. The
>only question is can I get it from yearly to maybe every 5 years? Note
>that the best geothermal firm in town designed and installed this sytem -
>the equipment and pipe sizes they chose all need to be redesigned at my
>cost. "This is the way we always do it and it works the rest ot the
>time."
>However, closed loop systems require careful design as to layout, type of
>pipe, depth of bury, and most critically, soil moisture (for horizontal
>loops). Dry soil does not transfer heat very well - wet soils are great
>for heat transfer but terrible to work in for the installation. Dry sand
>has air in it which is an insulator and thus impedes heat transfer and
>reduces the efficiency or capacity of the collector field. Most
>installers use sand backfill to protect the pipes from crushing by clods
>of earth. If the groundwater is below the trench the sand will dry out
>and the field will not transfer enough heat unless it has been designed
>and sized for dry sand. Some guys will design for the damp clay
>surrounding the trench full of dry sand. Backfilling with thermal grout
>makes the installation efficient but more expensive.
>Vertical loops are better but require a lot of connections all of which
>are prone to leakage if not done right. Also, vertical loops use 50 ft
>deep holes, or deeper, but the connecting pipes are typically installed
>only 3 feet down which is within the 6 to 8 foot deep frost zone around
>here. So a lot of the heat brought up from the depths is lost enroute to
>the house - nobody will insulate the collector pipes. I went through this
>with several of the bidders on our system.
>My experience is that the geothermal industry is over-loaded with get
>rich quick artists with little technical competence and less ethics. The
>capital costs are in no way warranted by what are essentially simple and
>cheap systems. I got several excellent references for my first HVAC guy
>but then he started demanding $10,000 advances before doing any work, he
>used the world's worst well driller for our wells and then the police and
>tax collectors showed up - police wanted to arrest him for taking 5
>figure deposits from other people and never doing any work and the tax
>guys wanted to garnishee anything we might ever have paid him. We fired
>him and got a new company that was pretty good but then it was a case of
>them not warranting anything the first guy did - logical. There are some
>good contractors, I think our second one is, but they are few and far
>between and tough to identify. I found as many good references for the
>crook as for the second company. The crook did just enough good honest
>work to get references for his real scam.
>There are guys installing horizontal loops only 3 feet down in our area
>(had one guy quote this)where the frost goes 6 to 8 feet down. Sure you
>can suck energy from frozen soil but the hit in efficiency is significant
>and prevents re-couping the investment. We have friends with geothermal
>heating, open loop, who are paying more for heating than they did with
>their old natural gas system. Geothermal thermostats have red indicator
>lights showing when the electrical auxiliary heat cuts in and the red
>lights are on most of the winter - so they essentially have an
>inefficient electric furnace. They were ripped off by an uneducated
>installer and incompetent well driller - their wells are very shallow,
>the same depth casings and very close together so the water simply short
>circuits - after a day or so they are re-pumping the same water and the
>flow path through the ground between wells is too short to pick up much
>heat. The geothermal heat pumps loose efficiency quickly with lowered
>temps for the incoming water. Since open loops are pumping water, not
>anti-freeze, there is a safety shut-off required to prevent cooling off
>the water so much that it freezes and bursts the heat exchangers. Thus
>their geo system often shuts down and reverts to electric - most of the
>time. The electric auxiliary heat is just a few cheap wire coils (looks
>like a 1960's portable heater) which are much less efficient than a
>modern electric furnace. Their contractor is out of business, or has a
>new name, and the well driller was only responsible for doing what he was
>told by the contractor so they are left with no recourse at all.
>Closed loop systems require a special thermal grout to achieve good heat
>transfer from the soil to the pipes but the suppliers I spoke with don't
>even import that stuff into our province despite several thousand systems
>having been installed. Vertical systems should have spacers between the
>pipes to locate them as close as possible to the hole walls and thus get
>the best heat transfer - I watched two installations at other houses and
>they not only didn't use spacers but taped the pipes together to make
>them easier to force down the hole. "We always do it that way" was the
>response to my question.
>In summary - geothermal works and the cost savings are there but the odds
>of getting ripped off and getting an inefficient system are very good -
>research the contractor more than the system. All the sytems work well if
>properly designed and installed, few of the contractors do. Don't go
>open-loop no matter what they tell you. Open-loops suffer from iron
>bacteria, calcium deposition within the pipes and heat exchangers, air
>locking causing the injection well to over-flow (try fixing that in the
>winter while water flows into your neighbor's yard and imagine how much
>you are going to get sued for if it reaches his house), poor well design,
>poor well drilling and lots of things that I forget right now or haven't
>happened to me, yet.
>The most irritating thing is that the initial costs are grossly inflated
>because it is a whatever the market will bear industry. Geo wells are
>simpler and cheaper to install than water wells but you get charged a lot
>more "because it is geothermal". Use only a firm that has been in
>business for many years - a lot of the companies around here are new or
>are changing their names every few years. The many poor installations are
>starting to pile up and when the warranty hassles get too much it is
>cheaper to kill the company than do the work. Many geothermal errors are
>very expensive to fix - a new well is $10,000 to $15,000 IF a drill rig
>can get into the site after the house is built, same sort of costs to fix
>closed loops. Double those costs for expensive landscaping that has to be
>torn up so repairing a geothermal system will cost over $20,000 and could
>hit $30,000 to $50,000. Well infections can never be cured, according to
>all my research and best efforts so that's a permanent problem. Note
>injection wells spread the infection throughout the groundwater formation
>so disinfection is not like a simple farm supply well where some Javex
>will do the trick. Drilling a new well doesn't help because the infection
>covers more than just your yard. The lack of talent in the industry
>causes so many of these problems that the small cheap companies can't fix
>the problems they cause.
>If you do go open-loop get at least 5.5 inch inside diameter casing. Case
>one well at least 25 feet deeper into the rock than the other (offset
>casing depths so at least one fracture zone is not common to both wells -
>lots of luck getting driller to actually do it, install a double pitless
>adaptor and double pipes into the house (both wells; you'll need them
>sooner or later), locate wells at least 250 feet apart (can trade this
>spacing for more vertical offset in casing depth if in limestone), get
>best well driller you can find and make sure he, and everyone who works
>on the well, disinfects after working - a bottle or two of Javex at the
>time by driller and installer would have saved us a permanent
>disinfection hassle. These are just some of the things required that you
>will get resistance on when you deal with contractors. Our first
>contractor, the crook, had the well driller install a 5 inch casing but
>with the double pitless adaptor there is not room for a standard 4-inch
>pump so we are forced into expensive 3-inch pumps that are much less
>efficient. The well driller knew standard pumps wouldn't fit but he was
>going to get paid before we tried to install the pump.
>If you go closed loop make sure they use thermal grout or, better yet,
>that the pipes are in wet soil all year round (near the septic field is
>very good, thermally, but not so great if you ever have to search for and
>repair a leak), bury pipes at least 6 feet and over-size the collector
>field or at least make contractor produce the calculation sheet and give
>you time to check it out.
>Either horizontal or closed loops require at least a hundred heat welded
>connections that MUST be leakproof. Now imagine a contractor paying
>minimum wage to his guys to do such finicky work in the dust and dirt -
>never mind if it rains and mud is smeared on everything. It only needs to
>pass a pressure check, done much less carefully if you are not watching,
>and not leak until the cheque clears. Only the very best firms are worth
>risking this sort of work with.
>Something else I learned the hard way - use only one heat pump! We have
>two heat pumps and many of the problems are due to use of two heat pumps
>on one open-loop. Dividing the supply flows is a root cause of huge
>problems and that would also be true for closed loops, maybe worse for
>closed loops. Flow splits require use of balancing valves which are
>actually pressure reducing valves (PRV's). They work by throttling down
>flows through each heat pump to balance the flows. The trouble is
>throttling flows causes gassing - that is the hissing sound these valves
>make - solid liquid does not hiss. All installers use PRV's to balance
>flows and the results are air locked wells or air locked closed loops.
>Much better to use a larger heat pump and design a zoned system for the
>house. All the bits are accessible and a bit of trial and error is
>simple. NEVER allow a PRV on a system, closed or open loop. Nothing but
>trouble. Size the pump for a bit more flow than needed and use a variable
>speed pump to adjust flows further. NEVER NEVER use a PRV!!!! A single
>variable speed supply pump and a single heat pump is simple and has the
>best odds of working with minimal hassles. PRV's guarantee trouble - I
>told my installers "no PRV's" but they insisted and said if they caused
>any trouble they would take them out. The next year when the well
>overflowed there were huge bubbles coming out the top which came and went
>when I opened or closed the PRV. So they removed the PRV's and replaced
>them with orifices at the ends of the discharge pipes which I wanted all
>along. Then they sent me a bill for $2,200 for "improvements at your
>request". Best I could do was negotiate that to half. Remember, PRV's
>hiss which is air or gas and that air/gas is going into your well or into
>hundreds of feet long closed loop pipes. How are you going to get the air
>out? Who is going to pay for fixing air locks? It won't be the guy who
>installed the PRV "because I use them all the time and they never did
>this before". Agravating thing is PRV's are NOT required as there are
>options which don't cause air locks.
>Fixing air problems in wells or pipe loops is as complicated as debugging
>a computer program with no end of possibilities and ways to deflect
>blame. It is a time consuming hassle and thus expensive to pay someone
>else to fix. Unless all the possible causes of air locking are found and
>corrected the problem will reccur and always at your expense. NO PRV's
>!!!