You should only need more loop pumping if your loop delta T is too high. Say greater than 8-9 deg F. Have you recorded loop temps with just 2 pumps on? Pumping power can add up quick and if you dont need it, it should be reduced if you can. You may need all the pumps, but maybe not. If you have glycol mix, you might be able to switch to methanol mix which is less viscous and possibly use less pump(s)

I think the contrrol scenario FrankZ talks about above will give you the geo hydroonic efficiency you are after (or the best chance of it). It sounds like you are yo-yoing the buffer way up and down in temps. The geo ends up having to push heat into the buffer at a higher temp (not efficient) at the end of the buffer heat up cycle than it needed to, and then all that hard earned heat just gets swallowed up once the call from heat starts the circulation. You need a more steady, hopefully lower, average temp in the buffer set by an outdoor temp probe. This is to get the best geo efficiency. Should yield a nice comfortable solution if you can get it dailed.

I think more data is in order.

Posted By tamar on 08 Apr 2013 09:00 AM

Posted By FrankZ on 08 Apr 2013 07:53 AM
Thanks, good advice I'm sure.  It really is amazing the range of stories you hear.  Some people put it in, turn it on, save a bundle every year, never have a problem.  Others have the installers back every few months for years trying to get it right till they finally give up, leaving a $30,000 system that they don't even use.  It's terrifying actually.

I do have A/C ducts that I could use for forced air, but they're all in the ceiling and they run through an unheated attic, so there would certainly be some loss of efficiency there, but maybe still a lot more efficient than trying to do hydronic with radiators, based on Tamar's experience. 

It really is shocking to me that geo is not saving us money. We wouldn't have done it if there hadn't been the big tax break to encourage us to go that way. We did not have air conditioning before, so this is really just like a really expensive air conditioning retrofit for us. I cannot complain about the comfort when the geo is working. I am hoping moving air through the basement also mitigates a slight radon problem we had (I was told it would; of course I was told a lot of things).

The projected spot-market futures for natural gas for then next couple of decades are SO low that there's little financial rationale for GSHP- it can't save enough in operating costs over the lifecycle of the equipment to make up for the initial high (even when subsidized) upfront cost.  If displacing propane or heating oil or higher-priced resistance electricity it's a very different story though- there's a very solid 10-20 year financial argument for GSHP in most of those cases.  But since you have the equipment in place, if it's reconfigurable to actually work right, it should have at least some savings over condensing gas, but maybe not- DEFINITELY not if you have to pay out of pocket endlessly for repairs. Yours is a prime-case example of the inherent design-risks associated of going with geo- the competence of designer/installer resources out there aren't exactly what we would hope for. (And it certainly isn't good PR for the competent geo designers out there.)

That's true for those designing heating systems around hydronic-fossil-burners too, but even if only 2% of those are competen (an estimate offered up by a deep energy retrofit contractor to me over the weekend, as we were commiserating sharing notes) it means that there's a chance you have at least a chance of finding one in your area who really KNOWS how to fix it.

Lowering the radon levels in the basement by mixing basement air in with the conditioned space air via the heating system may improve the numbers in the basement, bit isn't exactly a "solution", since it achieves that by increasing the radon levels upstairs.  Ventilating the basement with a heat recovery ventilator would displace the basement air with outdoor air (at the modest heat load & power cost of an HRV) for a far better solution.  The tried & true prescriptive method is to depressurize the slab with a fan on a pipe cemented into the slab, but the HRV approach can do about as well, and has other benefits.

Posted By Dana1 on 08 Apr 2013 04:52 PM

Lowering the radon levels in the basement by mixing basement air in with the conditioned space air via the heating system may improve the numbers in the basement, bit isn't exactly a "solution", since it achieves that by increasing the radon levels upstairs.  Ventilating the basement with a heat recovery ventilator would displace the basement air with outdoor air (at the modest heat load & power cost of an HRV) for a far better solution.  The tried & true prescriptive method is to depressurize the slab with a fan on a pipe cemented into the slab, but the HRV approach can do about as well, and has other benefits.

I guess I knew that, and I also knew that when we were installing the geothermail and when we had construction going on in the house including installing new equipment both in the basement and on the third floor was the time to do radon abatement. I was talked out of it by my installer.  Kicking myself, now, on many fronts.

I am just reading your thread and a lot of the setup does not make much sense. Do me a favor and check the model # and brand on those 3 loopfield circulation pumps.
Thanks

Doc, I am travelling for work this week, so may not be able to respond with that info until Friday. Just don't want you to think I am ignoring you or not being responsive!

Is everyone saying that my installer will need to take loop temps with both 2 pumps and 3 pumps running in order to give us the info on whether the third pump is needed? He seemed to indicate that there was some sort of calculation he could do based on length of loop and other metrics that he had.

Posted By tamar on 09 Apr 2013 10:49 AM
Is everyone saying that my installer will need to take loop temps with both 2 pumps and 3 pumps running in order to give us the info on whether the third pump is needed? He seemed to indicate that there was some sort of calculation he could do based on length of loop and other metrics that he had.

If he would have done his calculations right he would not need 3 pumps in series!
So let me get it straight, you have something like this:
http://welserver.com/WEL0545/
Old, inefficient, lovely Victorian in Minnesota. Used to live there. So you have a 5 ton split (model 64) and a 3 ton Water-Water, one of those rare but excellent high temp units, which are 3 tons and come in only a 3 ton size. Is the radiant on one single thermostat? Or multiple zones
Is radiant in the whole house, and duct work in the whole house?
Problem #1: The high temp unit can go to very high temps, but it is too small to feed your radiant system accordingly. Meaning it can make a small amount of water very hot, but it does not have enough capacity to make a lot of water very hot, the amount you would need in MInnesota for an old Victorian. Do you have cast iron or baseboard?

Do you have info on your loopfield? 1800ft, is that boreholes or pipe in the groung? What size of pipe and what is the configuration?

Did you notice that in the economical analysis they calculated with 4.5 cents/KWH winter electric rate, that is why your forecast is so low.

Posted By docjenser on 09 Apr 2013 03:12 PM

Posted By tamar on 09 Apr 2013 10:49 AM
Is everyone saying that my installer will need to take loop temps with both 2 pumps and 3 pumps running in order to give us the info on whether the third pump is needed? He seemed to indicate that there was some sort of calculation he could do based on length of loop and other metrics that he had.

If he would have done his calculations right he would not need 3 pumps in series!
So let me get it straight, you have something like this:
http://welserver.com/WEL0545/
Old, inefficient, lovely Victorian in Minnesota. Used to live there. So you have a 5 ton split (model 64) and a 3 ton Water-Water, one of those rare but excellent high temp units, which are 3 tons and come in only a 3 ton size. Is the radiant on one single thermostat? Or multiple zones
Is radiant in the whole house, and duct work in the whole house?
Problem #1: The high temp unit can go to very high temps, but it is too small to feed your radiant system accordingly. Meaning it can make a small amount of water very hot, but it does not have enough capacity to make a lot of water very hot, the amount you would need in MInnesota for an old Victorian. Do you have cast iron or baseboard?

Do you have info on your loopfield? 1800ft, is that boreholes or pipe in the groung? What size of pipe and what is the configuration?

Did you notice that in the economical analysis they calculated with 4.5 cents/KWH winter electric rate, that is why your forecast is so low.

I'll answer what I can while out of town, and verify the pump info when I get home.
Yes to old, inefficient, lovely Victorian in MN.
Yes to 5 ton split and 3 tone W-W
Highest temp W-W can achieve and handle is 140 degrees
Cast iron radiators throughout the house (except basement and our new kitchen, which was designed after the decision to go with geothermal)
SpacePak hi velocity system installed on third floor with new ducts throughout the house.
Single zone. Installer initially configured the system with 2 thermostats (existing one for gas Phoenix, and a new wireless stat for the combined geo units). Instructed to set the old stat for 2 degrees less than new stat. We were supposed to love the ability to carry our new geo stat from room to room, but that never made sense to me as the operation would then vary depending on which room the stat was in. After initial high heating bills (probably unrelated to us carrying the stat around, since we didn't do that), we got our first multistage stat.

I think we have boreholes, though I'm not sure of what the different terminology means. Vertical drilling was done, pipes are not laid horizontally.

Posted By docjenser on 09 Apr 2013 10:02 AM
I am just reading your thread and a lot of the setup does not make much sense. Do me a favor and check the model # and brand on those 3 loopfield circulation pumps.
Thanks

I just called home and got the following information about the pumps:
Brand is Grundfos; Model number is UP26-99 (hope that makes sense and these are what you were asking about).

Doc, the url you posted doesn't work for me, so I can't reply to that. Sorry!

The web energy logger website is down today. You can try again later.



To put 3 pumps like that in series is inefficient. Every time each heatpump turns on, all 3 pumps are running. So for example, when the 3 ton high temp turns on, needing only one pump to feed it with water, you are now paying for 3 pumps to run. 230 watts for each. It makes me concern that your installer really does not understand on how to design efficiently.
I know I am preaching to the choir here. We need more info on the loopfield.
Your thermostats scenario does not make any sense either. So you mean you can carry a thermostat from one room to another? I don't understand what that is that going to achieve?


I understand that the high temp is capable of supplying 140 F max, we put many hight temps in lately, although Waterfurnaces. The Carrier high temp is made by Climatemaster, which is I believe an older Viessmann design from Germany built here in the U.S. in license. The problem is that it is designed for very efficient european houses, but not for old victorians in Minnesota. It only has a capacity of 30 KBTU/h, which is at 104F entering load water temp, which means leaving water temp at around 114 F. If you run it up to 140F leaving, your efficiency drops by about 30-40%, and your capacity will drop to less than 25 KBTU/h.


So how do you heat a house needing 60-70 kBTU/h with a heatpump capable of making 25-30 kBTU/h? Under load, when the thermostat is calling for heat, it should never reach 140F since the load is much higher than the capacity, especially if you only have one zone. Also, if I recall correctly, the high temp has a built in outdoor reset, regulating the supply temps up and down with the outdoor temperature. Make sure it is set up correctly.



Your application screams for a high temp 7 ton waterfurnace with enough capacity for the whole house, an outdoor reset save you money and increase the efficiencies at the warmer days, thermostatic valves on each radiator so each one becomes a zone, and a hydronic air handler to receive chilled water for A/C. Will post some examples as soon as the welserver is up and running again. In your contractors defense, those heatpumps became available in summer 2012, and were developed for exactly your application:


We need some detailed info on your loopfield, and current piping and design to see you you can salvage what you have. Some of it appears to be control setup, but most of it seems to be design issues. Can you or your contractor provide some sketch on how it is piped ?



The good thing for you are large, oversized radiators. The more BTUs you put out at lower water temps, the more efficient your system will be.

"Is everyone saying that my installer will need to take loop temps with both 2 pumps and 3 pumps running in order to give us the info on whether the third pump is needed?"

No I think your installer should take third pump offline. No measurment required.

Doc has some good thoughts on what might save the system (though I assume purchase of the WF 7ton is off the table right now . Individually controlling radiators is a great idea instead of turning whole system on at once. You probably have enough geo equipment there to run well, but not enough installer know how.

Let me clarify the thermostat issue:

Our first configuration used our existing T8600 for gas, and a portable thermostat (despite my protests) for the Geothermal portion of the system
After the first rewiring of the system to try to get cost down, the T8600 no longer worked because the current to the stat was cut every time the boiler call for heat ended
We had a T8602 lying around (I used to work at Honeywell), so that was installed to replace the T8600
Another month of high heating bills prompted our architect to get involved and suggest a single multi stage stat
There was some kind of bug in that stat model so Honeywell replaced that stat after a few months
After more erratic behavior (switching from calling for heat to waiting for equipment for no apparent reason, as an example) the stat was replaced again
We kept complaining and finally a tech believed us when he saw it happen. It was determined that there was radio interference (possibly from a neighbors hamm radio), so wires were pulled and a hard wired stat was installed. That's where we are now.

Are there 2-3 specific questions about the loopfield that I can email to the installer to make sure I get the right level of detail and right facts about our loopfield and pipe?

Posted By joe.ami on 10 Apr 2013 08:30 AM

You probably have enough geo equipment there to run well, but not enough installer know how.

If only THAT were a rare one-off thing, eh? 

It's contractors like them who give the industry a black eye- putting in too much system from the get-go, with only the vaguest clue as to how to make it all work.  There is not a lot of hard published data out there, but I'd hazard overdone underperforming geo systems are well into double-digits percentages for the installed base in the US, though the scale of screw-up on this one probably puts it in a special class comprising only a single digit fraction of the whole. (Feeling lucky yet? ) 

Not every air conditioning & refrigeration tech has what it takes to design one of these systems, and I wonder just how folks like this end up in this business(?). I suspect there's a lot of on the job training (both the good and the terrible) that takes place, but without sufficient numbers it's hard for us amateurs to weed out the geniuses from the idiots easily. 

Does anybody here have a good bullet-list of how to vet your geo contractor prior to signing on for the whole-shebang?  (Performs heat load calculations first? check. Heat load calc is consistent with fuel-use history? check.  etc)

Oh yeah, nearly forgot...

I guess amongst the checklist for installers is take the advice of who you hire. Not picking on OP but I believe at one point installer advised against high temp. Doesnt forgive them for getting over their heads but the risk is shared at that point.
It also sounds like they intend to help customer make best of it so........

Folks here often complain about high cost of geo but expect installers to get the checkbook out when something goes horribly wrong.
We routinely pay to solve problems that are or arent our mistake. It is my feeling that customers dont care whos mistake it is they just dont wanna hear they owe more. We of course charge up front enough to do this and often are employed to fix the work of "cheaper" guys when they run from trouble..
Im not sure any of this has much to do with OP but it sounds like installer is trying so I'll reserve judgement on their character.

Posted By joe.ami on 10 Apr 2013 07:33 PM
I guess amongst the checklist for installers is take the advice of who you hire. Not picking on OP but I believe at one point installer advised against high temp. Doesnt forgive them for getting over their heads but the risk is shared at that point.
It also sounds like they intend to help customer make best of it so........

Folks here often complain about high cost of geo but expect installers to get the checkbook out when something goes horribly wrong.
We routinely pay to solve problems that are or arent our mistake. It is my feeling that customers dont care whos mistake it is they just dont wanna hear they owe more. We of course charge up front enough to do this and often are employed to fix the work of "cheaper" guys when they run from trouble..
Im not sure any of this has much to do with OP but it sounds like installer is trying so I'll reserve judgement on their character.

I hope the documentation of our experience is helpful to other customers considering geothermal. On our end, we did not know what we did not know, and we did not take the time to learn it, so yes, we share the risk/blame.

In our case, we had the company out to get a bid on a replacement boiler, and only in passing brought up the question of whether GSHP could be used in MN for radiator heat. We thought it couldn't, but they said it could and so our first conversation was only related to WtW GSHP with a boiler back up. My recollection (which may be faulty, so don't read too much into this--it was 3 years ago now) is that a subsequent conversation went down the road of "as long as you/we are paying for drilling and setting the pipe" that adding air conditioning with hi-velocity would only be incrementally more money. I also seem to remember that adding the WtA would put the system in the category of being able to supply close enough to 100% of our heating requirement to qualify us for the 30% tax break. Neither my husband or I realized that the WtW became the auxiliary heat in this proposal. We both think (in hindsight, which is 20/20 of course) that if we had known this we might have questioned even installing the WtW.

Joe is absolutely right, the installer to his credit continues to work with us, though I suspect we are one of his least favorite customers. As I mentioned in an earlier post, I did make an assumption that there was no way a new technology that every google search says is energy efficient could cost us more in monthly heating bills than a 40-50 year old boiler that was on its last leg. This is definitely a cautionary tale in that regard.

I continue to appreciate all the helpful suggestions/thoughts that you experts are providing. I got an email from our installer this evening that he has not made progress on the pump evaluation. I replied and asked him for the detail that your requested above on the loopfield and piping.

Let me clarify here that one of your issues is that your entire house is one zone, on 1 thermostat. It does not matter what thermostat, the issue is the lack of capacity on the load side. Here is the math (Dana would be proud of me!):

Lets say your radiant system has 500 gallons of water, meaning about 4175 pounds of water. Meaning when a call comes from the radiant zone thermostat, and it was parked at ambient temperature, and you need to bring this water up from 70F to 100F to get anything meaningful out of them, that itself takes about 125,000 BTUs. How do you do this with a heatpump that makes lets say 35,000 BTus/h under those working conditions? Plus now the radiators loose heat to the house. It does not matter if you heatpump can make 140F, it does not have enough capacity to heat the amount of water up to that temperature. Your heatpump is too small!

Here is what you need to get some meaningful performance from your radiators:



1) You need a buffer tank for the hydronic system, that way the heatpump can continue to run and make up heat when you don't need it.

2) You need an outdoor reset controller to lower the temps when they are not needed.

3) You don't need to, but would benefit from thermostatic valves on your radiators. That way not the whole house gets heat when only heat is needed in one area.

4) Most importantly you need a higher capacity heatpump. I would put a 5 ton in there, and have the high temp supplement it as 2nd stage.

5) Not sure what the 5 ton split will do here (A/C?), maybe it can be the second stage on colder days. So you can run the radiators up to 110F, and then the split unit kicks in to supplement.

6) Throw out all 3 circulation pumps, and replace it with 1 Wilo Stratos pump, using a fraction of the power. You would also need high CV valves at the heatpumps to shut off the flow when the pump is off. The Wilo would recognize the increased pressure after the valve is closed and would rev down automatically.

7) Joe thinks that the 7 ton Waterfurnace is off the table, but giving this mess, this might be the cheapest option to make it all right. Once you pop in a new 5 ton, the 7 ton is not too far away in price. The risk is that the 7 ton needs flow, something your installer does not fully understand.



The Welserver is up again.

So here is the Victorian:


http://welserver.com/WEL0545/

We designed it with the boiler as a supplement, but thanks to the "oversized radiators" it never turned on in the last 3 years.



Here are a couple more examples where geo works very well in conjunction with cast iron radiators:

http://welserver.com/WEL0424/



Here is one with boiler as second stage:

http://welserver.com/WEL0267/



Here are the stand alone high temps:

http://welserver.com/WEL0602/

http://welserver.com/WEL0664/



This is not to brag here, but for your contractor to get some ideas on how to make this work efficiently. The ingredients are always the same:

-Variable speed DC inverter driven circulation pumps.

-Enough capacity due to lack of supplement bailout (sorry Dana).


-Lowest possible supply temperatures

- Buffertank for hydronic

- Zoning

- Pipes designed for low pressure drop and valves with high CV => high flow. It is all about flow to transfer the heat!

Doc, I wish we could get information similar to what's in your links. When I've asked, what I've gotten is hand-sketched. When I get back to MN I will take a picture and post what I have if I can find it. Earlier this evening I asked the installer for loop field and pipe info to have a third party weigh in on pump configuration, and he responded that they wanted to do the calculation.

I wonder if there is a secondary market for the W2W unit. I am guessing it is just perfect for some other application, though our particular system/units seem to be generally cursed.

I told my children when they were young......2 words to live by: dad is right! -
Look we are all grown-ups here and things have gone wrong. while the cheapest operating advice belongs to Doc's fix the dollars will only make cents. for now go with gas. better to bring down the load and make what you have work better than bring up the tons.
Few have more respect for Docs advice than me, but more geo aint always the best fix.

I am not thinking here for the customers to buy more stuff. I am speaking out what I would do if I am the installer, and need to make good on it. They paid a lot of money to get a geosystem, settling for a gas boiler should not be the option. They were handed an operational forcast when the calcs were done with an unrealistic low 4.5 cent/kwh.
The fact that some of the ideal equipment was not available does not mean that they should sell you stuff which had no chance to work. So all is in view of the installer saying that they do whatever it takes to make it right. Well, here is their road map!

It does not matter if you heatpump can make 140F, it does not have enough capacity to heat the amount of water up to that temperature.

I would be careful about confusing slow response with lack of capacity.