Geothermal

Tom_133

Hello All,

thanks for taking a minute to look at this post.

As some know I live in the cold state of Vermont. Lately the phone has been ringing for some geothermal jobs mostly ground to air and some ground to water. I have always shy'd away in the past due to having a lot of unknowns. So when the calls came in I started doing some research. I called my local wholesalers to ask what they have found that works and they told me "we no longer sell the equipment". I was a little stunned. I asked why and they said "we have lost a lot of money on ENGINEERED jobs". I asked what the problem was and they said "even when done right they struggle to keep up when we are in the below zero temperatures".

I am not a guy who enjoys ripping out equipment for lack of working and going to work to lose money. So before I go to far in I wanted to ask if anyone else has had good success with geothermal in my type of climate basically a design day of -20 with 20MPH wind?

We spent a week at design day this year, and those who went heat pump mini splits were not impressed with the comfort or the electric bill.

Thanks in advance

Tom

Hot_water_fan

It sounds like the problem isn't geothermal in this particular case (although geothermal has many other problems, mainly initial cost and efficiency vs. air source). If the wells and rest of the system is properly sized, the system will keep up. If not, it won't, same as gas/propane/oil/wood/air-source heat pumps. There's probably a sweet spot where you slightly undersize it and use a backup/better insulation for the design temperatures.

Jamie Hall

As a fellow (in my case, ex-) Vermonter, @Tom_133 ,I empathize. Most flatlanders -- even the transplants in the fancy towns (who all flee to Hollywood or Florida anyway) -- have no appreciation of what a Vermont winter really is. As a result, they will woefully undersize almost any heating plant.

There is some experience with geothermal in the upper midwest and the prairie Provinces of Canada. I don't know much about it, but what I do know is that the installations tend to be much bigger than one would expect, and all the successful ones I've heard of use multiple deep wells (several hundred feet to thousands) as their sources, rather than shallow wells (up to 100 feet) or buried grids. Air source heat pumps are, so far, useless.

hot_rod

Tom_133 said:

Hello All, thanks for taking a minute to look at this post. As some know I live in the cold state of Vermont. Lately the phone has been ringing for some geothermal jobs mostly ground to air and some ground to water. I have always shy'd away in the past due to having a lot of unknowns. So when the calls came in I started doing some research. I called my local wholesalers to ask what they have found that works and they told me "we no longer sell the equipment". I was a little stunned. I asked why and they said "we have lost a lot of money on ENGINEERED jobs". I asked what the problem was and they said "even when done right they struggle to keep up when we are in the below zero temperatures". I am not a guy who enjoys ripping out equipment for lack of working and going to work to lose money. So before I go to far in I wanted to ask if anyone else has had good success with geothermal in my type of climate basically a design day of -20 with 20MPH wind? We spent a week at design day this year, and those who went heat pump mini splits were not impressed with the comfort or the electric bill. Thanks in advance Tom

To me, geothermal is either ground loops, wells, or lake loops. The geo part of geothermal😉Properly designed and installed they work in climates like yours. Keep in mind they are starting with a 50F or so source temperatures
IGSHPA has plenty of data on geo systems, check their site,
Jay Egg does a lot of seminars and articles on ground source systems.

Where as A2WHP are using outside ambient air temperature. At -20F outdoor, that is a huge lift. So the air source will struggle with efficiencies and supplying low temperatures, below 120F SWT

There is data on those cold climate systems. I know Siggy is on his 3rd winter above Utica, NY with a SpacePak Soltice. They must be working as both his son and daughter have systems he designed around that area

Mini splits are installed in your area? They use ambient air to scavenge the heat.  If air to air performs seems air to water should have a slight advantage

If I were looking at a job that has a boiler already m, keep it for assist or backup until the HP proves itself.

ayetchvacker

If an “engineered” grounds source isn’t doing a good job it’s definitely the fault of the “engineer” not the technology. The ground is a reliable heat source, right? I’m in favor of air source as primary with a backup for the 10% or less days of the heating season that it may not keep up. I think the ROI for installing a geo with ground loops is pretty bad even with DOE rebates. And if the loop fails....

Tom_133

I appreciate the comments, the next problem I have is the engineer. Typically I do my own on boilers, but I would need a good engineer for these. So I reached out to a few, and got back they are months up to a year out. Any ideas?

wmgeorge

You do not need an engineer, find a geo installer with a proven good track record and references. Most engineers have no experience with geothermal and they have designed some monumental screw ups! I am out in Iowa where right now its a balmy Zero and that's a warm day. I doubt if Vermont is colder than Iowa and Minnesota where there are a lot of geothermal.

Climate Master and Water Furnace are both brands I am familiar with, check with them for more info.

FYI most geo Bore holes here are one 200 ft deep per Ton, Ground loops 400 ft per Ton but yours will vary from that.

psb75

Tom,
I know of two geothermal systems in Montpelier residences. They work fine. They were expensive to install. One of them has 3 drilled wells for geo-only. There is a lot of careful engineering involved: pumping large volumes long distances, sizing pumps and piping, well-drilling or trench digging (big machinery), heat-loss calcs. electrical etc. A good engineer would have an overview of the whole job. Like someone above said, the technology is proven. But if it's not designed and constructed carefully....expensive "woe" ensues.

george_42

I am in central PA And put in geo 4 years ago In anew build well insulated 3000 sq ft home. Two 300 ft wells supply 4 tons of capacity. This system keeps us as cool or hot as we wish.I put an amp meter on my geo unit and summer or winter use about 75 to 100 dollars of electric for this unit over 4 years . We love IT

wmgeorge

Yes do not install in a old house without good insulation or windows. Do not go by rule of thumb estimates. Get a good installer with reference's.

hot_rod

If you have an hour here is a good non biased webinar comparing air source to GEO.
With enough land, a trenched system can be less $$, compared to drilled wells.
https://www.youtube.com/watch?v=Z8E8aqeiCik&list=PLuuV0ELkYb5VE0I4evUZ30b5U78CRlRdg&index=4

EBEBRATT-Ed

@Tom_133

Geo will work the ground water is a constant 55 degrees. I have used Water Furnace and thought they were good quality.

The big issue is the wells very expensive and a lot of work. The last job we did in MA. (Greenfield area) the well guy was out of NH I believe so you may look them up. Too many years for my memory.

I wouldn't do anything but a closed loop

ethicalpaul

Hot_water_fan said:

It sounds like the problem isn't geothermal in this particular case (although geothermal has many other problems, mainly initial cost and efficiency vs. air source).

Hi @Hot_water_fan -- I'm curious why you say that geothermal has a problem of efficiency vs air.

I had a great ground source engineer but I don't know if he goes up that far. He has sized and planned many systems.

He knew a great driller as well who came in and sunk a 550' well in my driveway in a day and a half, piece of cake.

Here he is: http://www.litchfieldgeothermal.com

I would think if you had an accurate heat loss he could work with you to find a good system for it. The biggest part of the job he did for me was the heat loss. After that, you just match the tonnage of the heat pump to the capacity of the well (or trenches, or pond, whatever)

Hot_water_fan

Hi @ethicalpaul

I'm curious why you say that geothermal has a problem of efficiency vs air.

I've seen studies (including this one from @wmgeorge https://sustainabletechnologies.ca/app/uploads/2015/12/ASHP-GSHP_TechBrief_Final.pdf) that show that the gap between ASHP COP and GSHP COP is really narrow (3.23 vs. 3.44 from the linked report), which makes a $20k upcharge difficult to justify economically.

As ASHP's have improved, the GSHP face diminishing returns on efficiency. A big source of GSHP's struggles is the wells themselves since they require significant pumping energy. It's a retreating horizon as well - as ASHP's improve, the gap will narrow. Plus add in solar's cost declines and the kwh saved by geothermal look especially expensive.

Obviously, situations will vary but geothermal faces many obstacles. It's best when you have large heat loads, high electricity costs, and long heating seasons. But even in those situations, your money is probably spent more effectively elsewhere.

Jamie Hall

I like the cheery comment up there that if you have the land you can use trenched loops, coupled with the equally cheery comment that ground water stays at 55.

Well, not always. In central to northern Vermont the normal -- that's normal, to be expected every year -- depth to freezing is taken as 4 feet. Even in western Massachusetts and Connecticut, depth to freezing is over 2 feet everywhere, every year. Now then, to reach water or ground above freezing -- let's say 40, never mind 55 -- you are going 6 to 8 feet with your trench. Feasible? Certainly, assuming you don't hit bedrock (there's some of that around, here and there), but your trenching costs are considerably more than double as now you are in OSHA shielding territory.

The assumption that ground water will be at 55 is only true at depth -- say a couple of hundred feet or more -- in more northern climates.

I've said it before, and I'll say it again: be sure when you state how well something works, that you add where it is that it worked.

wmgeorge

Gee, they are selling and installing lots of Geothermal out here. What is the advantage compared to air source? Stable ground temps vs when its really cold geo has the advantage over air source, and summer same thing. Right now Geothermal is the hot market in the US, why do think? What size pump do you think it takes to pump the sealed loop?? You might be surprised, unlike a deep well pump since it is a sealed loop the pump only needs to move 3 gallons per minute per ton and the pumps I have seen are 1/2 hp. I have been on several Geo jobs and saw them installed and working.

https://www.waterfurnace.com/residential/products/geothermal-heat-pumps/

Hot_water_fan

Right now Geothermal is the hot market in the US, why do think?

I'd like some supporting data here - I don't think the ground source heat pump industry has grown much nationally recently, but prove me wrong. It's definitely not one of the hot markets, maybe warm.

3 gpm/ton of a water/glycol mixture through 1000 ft of tubing requires an non-trivial amount of energy.

wmgeorge

Hot_water_fan said:

3 gpm/ton of a water/glycol mixture through 1000 ft of tubing requires an non-trivial amount of energy.

3 gpm/ton of a water/glycol mixture through 1000 ft of tubing requires an non-trivial amount of energy.

Usually 1/2 hp circulating pump or less since its a closed loop.

JayEgg

Erin from HeatingHelp shared this discussion with me. We have been engineering these systems for almost 35 years. There are millions of these systems around the world that have been operating well for decades. http://bit.ly/GeoCaseStudiesEgg -Reach out to anyone with a proven track record and you'll have a successful project. We'd be pleased to provide peer review on projects if you wish.

wmgeorge

Thank you Jay, I have been trying to answer questions here but its been 15 years since I was involved in this. When I was teaching I worked with Kurt Clausen a engineer with the Iowa Energy Resource Station but that was a long time ago. I introduced Geothermal and began teaching it at the CC in the mid-1990s.

Jamie Hall

Welcome aboard, @JayEgg . Your input will be welcome! And very useful...

Mark @ Radiant Works Inc

Hey Tom,

I am a geothermal contractor in Northwest Vermont and have been doing Geothermal for about seven years. The majority of my systems are water to water paired with  Radiant and a handful of water to air systems.  I have yet to have a customer call me and tell me their house is not heating properly. I do advocate a back up source of heat in the event the geothermal goes down since it’s not main stream in this part of the country, meaning if a compressor goes down  I can’t just run to the wholesaler grab another one and have it changed out in three hours. I will usually size the system to handle 80-90% of the load so The system is running at peak efficiency for the majority of the heating season. Those few days when it is -20 some auxiliary heat may kick in.  A heat loss is a heat loss, No matter what the type of equipment that is installed whether it’s propane oil or geothermal. The key to a successful relationship with your customer is to be right up front with them so they don’t have expectations that you didn’t design for.

Happy to talk with you more about this off-line if you’re interested. 

wmgeorge

Here in my city and I did not agree but it got done, they replaced the H&C systems in 3 of the schools with Geothermal. Bore holes under the playgrounds and buried the pipe of course. Cut the power bills by 40 and 50% for heating and cooling. A lot of misconceptions by folks who have never seen or installed Geo.

Erin Holohan Haskell

Jamie Hall said:

Welcome aboard, @JayEgg . Your input will be welcome! And very useful...

I agree. @JayEgg, wrote the book on geothermal and is an excellent teacher. Thanks for joining this discussion, Jay.

gunn308

I'm a little farther north in Maine, RSU 22 Hampden Academy has been geothermal for 10 years and have had no complaints other than initial start up and rundown to get the bugs out.. Elco Electric in Bangor did the install. I know residents weren't too happy because the local LNG supplier said they would run an 8 mile line for the new school which meant the whole community would be able to eventually get hooked up.

Tom_133

Wow, lots of thoughts. I appreciate the knowledge. It sounds like if the house is built to the spec that the print suggests and the system is designed to that spec, then we can be very successful. I will start with an accurate heat loss. Is there a manufacturer that seems to be especially robust, or is it like anything else, the install is the most important part?

Mark @ Radiant Works Inc

Tom,

A good resource is Water Energy out of New Hampshire. They are the dealers for ClimateMaster, which in my opinion they are top shelf, have been around for a long time and aren’t going anywhere like half a dozen other manufacturers who brought Geothermal into their mix  and then dropped it. Water Energy will design your system for you and stand behind it. They’re on the web, speak with Matt Oreole… his dad wrote the book on standing column systems in the northeast but they’re big into close loop systems as well. 

george_42

Through 2022 there is a 22% federal tax credit on geothermal and some states also give credits . The general rule is 150 ft of well for each ton of capacity. I have climatemaster in my home and it is wonderful.I posted earlier that I use about $75 a month for my 4 ton unit for 3000 sq ft home. If you are building newI would suggest using spray foam insulation , which is about twice the cost but much better, George

EBEBRATT-Ed

I believe Water Energy did the closed loop wells for us . The job was a restaurant in Bernardston, Ma. Couldn't remember their name but I knew they were from NH. That was probably 8-10 years ago

My boss used AAon equipment......stay away from that stuff. There is better stuff available

JakeCK

Wish I had the budget to convert my fhw system to geothermal.

leonz

Speaking as a certified well driller and pump installer;

We were taught 100 feet of well bore per ton of heating or cooling need.

When people start bragging about "thermally enhanced grout for thier drilled well geothermal systems do not believe it as the thermally enhanced grout has clay in it which is a natural insulator which would automatically reduce heat exchange.

If your going to drill a geothermal well use mason sand instead of the magic thermally enhanced grout as it will cost much less as all you need is water and mason sand pumped down the tremie pipe to fill the well bore.

Steamhead

wmgeorge said:

Here in my city and I did not agree but it got done, they replaced the H&C systems in 3 of the schools with Geothermal. Bore holes under the playgrounds and buried the pipe of course. Cut the power bills by 40 and 50% for heating and cooling. A lot of misconceptions by folks who have never seen or installed Geo.

What systems did these schools have before?

wmgeorge

Steamhead said:

wmgeorge said:

Here in my city and I did not agree but it got done, they replaced the H&C systems in 3 of the schools with Geothermal. Bore holes under the playgrounds and buried the pipe of course. Cut the power bills by 40 and 50% for heating and cooling. A lot of misconceptions by folks who have never seen or installed Geo.

What systems did these schools have before?

They had gas fired hydronic boilers and main AHU or room units. Most had chillers, some of this stuff was less than 10 years old. As far as I was concerned it was not a good economic choice.

Jamie Hall

Minor comment. Before you get all enthusiastic about drilling a well or a few wells. First, not every 100 foot length of well is going to be the same. The deeper you go, the more stable the temperature is and the warmer it is in winter. That makes a differene.

Second, keep in mind that some jurisdictions -- State or local -- have very strict requirements for drilling wells. Not only on how many you may have, or how deep, but on exactly how they are constructed and who may do the work. There are good reasons for these restrictions. If aquifer contamination occurs because of your well -- or even if there is a possibility that it might be your well that is the problem -- you are responsible for proving otherwise, and if you lose for cleaning up the problem. This can get expensive... so do it right the first time.

wmgeorge

Jamie these Geo well / bore hole drillers know all this, not their first rodeo. Geothermal has been around for a long time 30-40 years or a lot more. You folks out East perhaps not. Yes depth depends on the local soil and ground temperatures.

Jamie Hall

wmgeorge said:

Jamie these Geo well / bore hole drillers know all this, not their first rodeo. Geothermal has been around for a long time 30-40 years or a lot more. You folks out East perhaps not. Yes depth depends on the local soil and ground temperatures.

Quite true. I was writing more for the folks in California or the east. In the east particularly there is a somewhat unfortunate combination of not too well informed enthusiasts and contractors who don't mind making an extra buck.

Hot_water_fan

@wmgeorge Technical challenges aside, there's a huge cost premium with geothermal. You need to save a lot of kWhs to make up the gap in installation costs. With solar at $3/watt unsubsidized, the efficiency gains need to come in very cheap to be economical.

wmgeorge

Hot_water_fan said:

@wmgeorge Technical challenges aside, there's a huge cost premium with geothermal. You need to save a lot of kWhs to make up the gap in installation costs. With solar at $3/watt unsubsidized, the efficiency gains need to come in very cheap to be economical.

Its not for you East coast folks for sure when you paying 22 cents a kWH. But for the rest of the USA and yes it exists... Geothermal is very popular. Thanks to greenies and tree huggers we are going to be forced to abandon NG the best fuel we have.

Hot_water_fan

Its not for you East coast folks for sure when you paying 22 cents a kWH. But for the rest of the USA and yes it exists... Geothermal is very popular. Thanks to greenies and tree huggers we are going to be forced to abandon NG the best fuel we have.

I'm comparing air-source to ground-source, which both use electricity. I'm focusing on residential for now. My critique is that there's a large upcharge over air-source and it's hard to save enough kWhs to justify it especially when insulation and solar can save/generate kWhs cheaper than ground-source. Maybe 5% of the time ground source beats air-source? 10%?

You linked a study once from Canada that came to the same conclusion. Caleffi's Idronics also detail the challenges to wide acceptance of ground-source when compared to air source. I'm not saying it's never economical, just that probably 9/10 times it is inferior to air-source.

I have seen zero evidence presented that residential ground-source has a large market share.

I didn't say anything about gas.

wmgeorge

Well I do not have time to do the research right now and you seem to want to prove something. Go for it. I know the facts because I have been involved in the past with Geothermal.

Hot_water_fan

I know the facts because I have been involved in the past with Geothermal.

Geothermal works! I'm not disputing that nor am I discounting your experience at all. The question is how often is it worth it vs. air-source. It seems to make the most sense where electricity prices are high and winters are cold, but even then it's marginal.