/r/geothermal

Photograph via snooOG

A reddit focused on geothermal energy and geothermal electricity. All civil discussions aren't just welcome but wanted.


The Geothermal Reddit

Geothermal energy is thermal energy generated and stored in the Earth. Thermal energy is the energy that determines the temperature of matter. The Geothermal energy of the Earth's crust originates from the original formation of the planet (20%) and from radioactive decay of minerals (80%). The geothermal gradient, which is the difference in temperature between the core of the planet and its surface, drives a continuous conduction of thermal energy in the form of heat from the core to the surface. The adjective geothermal originates from the Greek roots γη (ge), meaning earth, and θερμος (thermos), meaning hot.

Wikipedia: geothermal energy

Geothermal electricity is electricity generated from geothermal energy. Technologies in use include dry steam power plants, flash steam power plants and binary cycle power plants. Geothermal electricity generation is currently used in 24 countries, while geothermal heating is in use in 70 countries

Wikipedia: geothermal electricity


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/r/geothermal

4,677 Subscribers

3

How many years does it take for Geothermal to payback in Northeast?

14 Comments
2024/02/21
00:10 UTC

1

Shoot Holes in My Idea for Simple, DIY Geothermal Cooling w/ Hollow Micropiles

I purchased a house on a small (.21acre) lot in Downtown Phoenix a couple of years ago, and I'm interested in geothermal cooling for a couple of outdoor storage/utiility spaces that regularly see 120°F temperatures.

It's in a historic district, and comes with all the constraints on making upgrades/improvements, etc, so a major grading operation to put in the standard PEX loops at a depth of 8-10' isn't likely to get approved even if I had the cash.

I'm wondering about what kind of performance I could expect out of a system involving a dozen or so 4"-6" hollow aluminum or copper tubes (or possibly even galvanized steel or ABS) placed vertically with a water jet to a depth of, say 25' or so, in a single row or array with 2' spacing minimum, each plugged with concrete or clay at the bottom, and then bisected through it's cross section with a plastic or galvanized divider running the length of each tube that stopped about one pipe diameter from the bottom. I'd use a duct fan (or fans) to push air from the storage spaces down one side of each tube, which would go the bottom, pass under the divider, and then back up the other side, collected, and returned to the same space for a closed loop.

Volume would be kept low to allow time for heat transfer to the walls of the tube, and also to minimize friction losses.

I highly doubt I"m the first guy to think of this, has anyone ever heard of such a system?

6 Comments
2024/02/18
22:07 UTC

2

New to geothermal. Quick question.

Buying a home with a geothermal system and it's winter. The system can do both cooling (forced air) and heating (radiant heat). It's a single buffer tank system using HBX controllers and thermostats.

The system heats just fine, but when I set it to cooling mode, (even on just a single zone with other zones turned off), it just rejects my cooling instruction. The cold weather temp shutdown mode is not enabled by the way as it's not that cold right now.

  1. Is it normal for a system in heat mode to take forever to transition to 'cold' mode?
  2. Any idea what's going on here? I've read all of the HBX documentation and can't find anything about why it's rejecting my call for cold service.
11 Comments
2024/02/17
03:07 UTC

2

Repair or Replace Question

Repair or Replace Question - Located in MidWest (Kansas)
REPAIR: $4,000

The existing unit is GeoExcel Model ES061 (I think this is a 5 ton unit, more than likely installed in 2005). HVAC tech states there is a freon leak in the air coil, and air coil needs to be replaced.
Replacement is Air Coil (part # 8-733-906366) $1,866
$48 for filter drier

$200 for freight

$350 for Freon

$1,210 for install

The HVAC company states nothing else is visibly wrong with the unit, but absolutely no way to determine what or when other parts will fail.

REPLACE $30,500... after fed tax credit $21K.
New unit: Furnace 5 Series 500A11 Dual Cap Symphony $19,995
Heater $1,059
T-Stat Color Touch $950
Flow Center $2,157
Desuperheater Storage tank 40 gal $665
50 Gallon Elect Water Heater $825
return air drop $150
plenum $150 + $120 other misc duct material
Installation $2,400

Interested in subject matter expert opinions: Repair or Replace?
How do the prices look? - both repair and new unit
Feedback on the quality of Water Furnace 5 Series Quality.

Are there other options I am not considering?
I plan on getting several more quotes - but there are not many options in the area. HVAC company that quoted seems to be a good company - but I have minimal experience with them. I purchased the home a year or two ago and system was existing.

6 Comments
2024/02/17
01:01 UTC

2

Has anyone worked with Geo.us? (southern ny -westchester)

I've been going around getting estimates and talking to different companies. ive been in contact with dandelion, Geo. us and have a call scheduled with clover cool next week. can anyone recomend anyone else?

Dandelion- has been by far the most professional (upfront) but their timelines and the fact that they subcontract everything out is a little iffy to me.

Geo . us - has been by far more "down to earth" than Dandelion, and does all their own work with much faster timelines, but offers 0 financing - everything needs to be paid in 4 stages, even the ConEd rebate. (its not a deal breaker)

Does anyone have someone they liked in Westchester that they can recommend?

11 Comments
2024/02/16
15:15 UTC

2

Service Contract

28 year old geothermal system in a house we are buying. Should we get a service contract? They want over $500 per year for 2 checkups and 2 service calls.

9 Comments
2024/02/16
01:33 UTC

2

How deep a trench needed?

For a horizontal geothermal system for a single family home in the Steamboat Springs, CO area, how deep should the pipes be buried? I have been told 7-8 feet which would be very expensive as I do not see any trenchers that go more than about 4-5 ft deep; would have to hire an excavator and make a stepped, wide trench for 8 ft, I believe. Anyone know of a machine that can dig a narrow 7 ft trench? TIA

22 Comments
2024/02/15
03:49 UTC

2

New Englanders - experience with WaterFurnace 500RO1? Retrofit, nat gas furnace/central air

Anyone in New England have experience with the WaterFurnace 500RO11 geothermal heat pump with outdoor compressor in dual-fuel configuration? We don't have a place inside for it, so an outdoor compressor is necessary and WF seems to have a good product. (I don't want to build a little house outside for the inside-only rated compressor unit.) How many tons or BTU/hr for a 2500 sf house, 2 stories. Townhouse, so 1 exterior wall already conditioned. Air handler on 2nd floor (nat gas furnace, want to keep dual fuel capability). Good insulation.

14 Comments
2024/02/14
22:03 UTC

1

Secondary market?

I'm wondering if anyone knows of the best secondary market other than craigslist?

I just got quoted ~$16,500 to swap out my Bosch SM060 Geo heat pump for a WaterFurnace series 5 with communicating thermostat, humidifier bypass etc etc.

House geo was originally a WaterFurnace that previous homeowners swapped for this Bosch about 4 years ago. Total energy hog and completely inefficient in the winter months, anything under 40° and this thing struggles and runs constantly. Electric bills peak just under $800 in winter months.

I'm hoping the WaterFurnace will be more efficient but I'm concerned that it will just be more of the same.

I can get roughly $5k back on tax credit, hoping to sell old unit for roughly $5k too bringing total costs down to about $6k.

Is selling this thing for $5k a ridiculous price for a used system?

Would I be better off spending $6k to install a 5 ton gas furnace next to Geo and just switching over once it goes below 40°? (Have an HVAC friend that can do that install for basically free, just need to buy unit).

What do you guys think?

Current gas bill is only about $16/month year round.

Current watt usage when geo runs in cold is around 4500-5000 watts per Sense app.

18 Comments
2024/02/14
20:47 UTC

3

Air trapped in condo geothermal heat pump

My apologies if this is the wrong place to ask, and also sorry for my lack of knowledge.

I live in a condo, we have a Trane geothermal heatpump (all units have the same system). Last few weeks I could faintly hear what sounded like water running through pipes in the wall or ceiling. I noticed it was louder today so decided to move the ceiling tiles and I can clearly hear and feel air trapped in the system, mainly in the "water out" line.

I'm trying to figure out if I can either fix it myself or do I need to call a pro, and if I do call a pro is it my responsibility or is this something management needs to deal with.

Thanks in advance for any help or direction on what to do next.

Cheers

9 Comments
2024/02/14
00:12 UTC

2

Building ontop of ground loop system

I have a geothermal ground loops system I installed around my property. There is a section I would like to build a garage on top off, I was going to do a thickened edge insulated slab, with a insulated foam skirting out from the footings.

I would still have 5'+ of material between my ground loop and the bottom of my slab.

Has anyone done this before? or is this a bad idea.

6 Comments
2024/02/13
17:57 UTC

4

Question about retrofitting century home for geothermal

We currently have boiler for heat and a split AC unit with external unit on roof and handler in top floor closet. We live in a 110-year-old home that has good ductwork installed for this setup. Got a few quotes to replace AC system with a heat pump to provide both heating and cooling, figured we'd look into geothermal as well.

I could only find one contractor (we live in Baltimore) who provided a reasonable estimate, but strongly recommended redoing all the ductwork. It sounds like there would be a way to keep current ducts and air handler location but he recommended against it. Unfortunately given the difficulty and expense with taking down walls and installing ducts in these old houses, this would put geothermal out of reach for us.

Does that recommendation to redo the ductwork seem valid to others? We are still learning the basics of geothermal so there's a lot of information asymmetry, which always makes me uncomfortable.

Thanks!

2 Comments
2024/02/13
07:03 UTC

2

5 Ton 71 EER2 GeoCool Geothermal Heat Pump

Anyone have this in a similar climate where winters are like upstate new york? Snow. Cold down to minus 40 but usually in The teens. I'm trying to get some sort of average energy usage to go off of for this unit since I'm trying to stay within my 14.7 kwh system. N trying to decide I'd I can get away with this cheaper unit...I'm in a 122 yr old place I'm at least gonna housewrap n reside unless I have to do more for code and fill up the attics with insulation n new windows. 2500 sq ft main level n upstairs. N basement is like 1400 sq ft. I'm more concerned about main level n have a feeling the basement will stay warm pretty easily since it's a basement n not fighting from outside temps. The seller isn't commenting cause they are saying it varies too much from house to house n that it starts at 35amps by a 240 v. If I'm reading specs right but that it just runs that way during start up. N doesn't that seem high?

6k geocool system

5 Comments
2024/02/13
01:50 UTC

4

Water Furnace 5/7 Quote

Hey all, looking for some feedback.

Have a quote for two units:

Water Furnace 5: $44,400 Water Furnace 7: $55,200

Drilling: Closed Loop Vertical Ground Exchange: $58,320

So all in total would be between $105k and $116k to install before tax credit.

We’d use the existing ductwork, so no real ductwork to install.

Trying to get another quote, but is this in line for vertical plus two units?

Thanks!

22 Comments
2024/02/12
23:28 UTC

2

Fighting with the Nest Thermostat to stop "Aux Heat" and "Heat Stage 2"

We got our geothermal system from Dandelion in 2018. It came with a Nest thermostat, and I've been fighting with it ever since. I've heard people say that with geothermal it's more efficient to leave it at one setpoint and let the system work gently, rather than have it setback the heat, and then work hard to bring it back up to temperature. But the Nest won't allow that. It tries to set back the heat at night, and whenever it decides we're "away" (which often means we're in the other room and haven't walked past the thermostat lately). I also don't believe that it can be more efficient energy-wise to keep the temperature at one setting all the time. I've played with some settings to limit how much it can lower the setpoint, and I gave up on the "learning thermostat" mode almost immediately, once I found the scheduling function.

I only heat the house to 63 F in the day, and allow a setback of 58 at night. But when it comes on in the morning, it goes straight to "Heat Stage 2" or "Aux Heat." I turned off the circuit breaker for Aux heat, because it completely undermines the efficiency of the heat pump by using a standard 10kW resistance heater. And when Stage 2 comes on, I can hear the heatpump working hard, so I'm afraid it's wearing itself out faster. I changed the schedule so that instead of going from 58 to 63, it goes from 58 to 60 at 2 AM, then to 62, and finally 63 by the time I wake up. So much for the easy to use "learning thermostat." Still sometimes I check the app by my bedside and see that it is in stage 2, so even those slight changes aren't subtle enough to prevent it from going to stage 2.

It seems to me that the Nest is a full blown turing complete computer, and it has "early on" and "time to temp" capabilities, so you should be able to program it to calculate how long it will take to get to the desired temperature, and then come on early using the lowest heat setting, to get to there by the desired time. I've considered just putting our old furnace thermostat back, but it seems to me that it isn't capable of controlling the various functions of the heatpump, so I haven't done that. But I find it very frustrating that this expensive, AI capable thermostat has to be outsmarted in order to get it to do what I actually want.

16 Comments
2024/02/12
18:34 UTC

3

ECM Config Error

Hey all.

A few days ago my Climate Master Geo-Thermal systems thermostat started displaying a flashing “ECM Config Error” message. The system kicks on and off without issue and when it runs the error goes away. I have noticed flow CFM is only about 60-70% of what it was previously

After some basic manual recommend troubleshooting I had a tech out to inspect. Other than testing the motor, incoming power etc there was no real clear indication of what was wrong. At one point in the service menu on the thermostat the tech did observe in the menu where CFM/stage outputs the displayed the values did not reflect what the manual stated, values were adjusted to little effect. Tech did say that the motor does not appear to be pulling additional amps, or demonstrating any resistance, but it is spinning slow.

I was quoted approx $1300 for motor replacement and labor, which seems fairish, but does this diagnosis make sense? Could there be another setting in the service menu on that thermostat that still needs to be adjusted?

Update: It appears to have been a thermostat issue. Somehow the System Program selected reset to the default value. Once that was corrected the system seems to be running fine.

1 Comment
2024/02/12
15:37 UTC

5

Water on pump, burning smell, aux

Does anyone know what could be causing it to run on auxiliary, a burning smell, and water on top of one of the pumps?

12 Comments
2024/02/11
21:51 UTC

2

Inside vs. outside

I am considering geothermal heat pump. The installers tell me they really want to put the "heat pump" indoors. House is on a slab. My air handler (currently forced air furnace w/ central air) is on the 2nd floor. There's no place inside for the heat pump - the water loop will be in the back yard and the living room and kitchen face the back yard. I want to have a little, well insulated "dog house" coming off the house for the heat pump, and run the lines up to the 2nd floor inside a fake downspout. Anyone have experience with this? Will be pretty cold in the dog house (this is New England)

25 Comments
2024/02/10
21:26 UTC

2

Where to start on choosing a system for a new build?

I am not an HVAC person. I can’t fathom assimilating all of the knowledge needed to come up with options, models, factors to consider, and all of the choices or decisions to make. Where do I start?

We are planning on a new build in Seattle, a 2-story, flat-roofed, modern home with windows, windows, and windows facing southwest-ish. Climate zone 4C, I guess.

I like the concepts of Warmboard radiant heating and Stellar Hardwood flooring. I’ll have a slab-on-grade workshop (roughly 2-car garage size) and want it heated as well, preferring radiant also.

I hate noise, so I don’t want a noisy unit in my yard or mechanical room if I can help it.

Conceptually, I prefer a GSHP but understand ASHPs have improved a great deal. Cost will eventually be a factor but not yet. I want to have some foundation of knowledge and such to evaluate the needs vs the options available.

7 Comments
2024/02/10
00:41 UTC

6

Does the 30% federal tax credit carry forward?

Was just speaking with my tax preparer and I’m planning to do both a solar and geothermal upgrade on my primary residence in 2024. He informed me that I can only claim for the combined tax credits in the calendar year of the installation and any unused credits expire i.e. will not be carried forward to be claimed against 2025 taxes. So if I do both upgrades in 2024 I will lose out on potential refunds unless I split up the installations into two calendar years. I’m reading some articles that claim carry forward of credits is possible. Looking for insights before I ask one of the installers to delay.

Edit: Credit DOES carry forward. Tax preparer was not accurate. Thanks all!

11 Comments
2024/02/10
00:06 UTC

2

Water furnace 5 series quote

Am I wrong in thinking a 47k quote for a water furnace 5 series is… high?

East TN… 3 ton unit. 2.6 acre property with big open flat space next to the house with basement hvac. Ducted system already in place.

Seems a bit much to be a 35k premium over a Bosch ASHP by same contractor. Still needs wiring, still expensive equipment, there’s extra material and labor of course but… seems high. I don’t know how much it costs to dig a trench and lay pipe in it but it seems… high. Feel free to correct me though

24 Comments
2024/02/08
22:30 UTC

1

Could one, in theory, drill for hot spring water? If within certain proximity from known geothermal springs

Simply curious with the thoughts of people that know more about this than I do. Curious on what one would have to go through to be able to access warm to hot water from underground without current surface spring. Safe to assume it would be expensive if at all possible?

11 Comments
2024/02/07
04:30 UTC

2

Recommended Installers in NJ?

I’m in the Jersey City area. Have reached out to Ryan(Ryanbuilds.com). They priced it out but now have gone silent for months.

Anyone else work in the Hudson County area?

Thanks!

2 Comments
2024/02/06
21:43 UTC

1

Geothermal vs NG cost with t-stat setback

We all know that geothermal is more efficient than natural gas, but what if you factor in setting your thermostat to 50 F at night for a NG furnace vs leaving t-stat constant (recommended) for geothermal? For me, I also need to factor in electrical costs for pumping well water for the open loop geothermal. I have about 100' of head on my well and my 240 VAC submersible well pump draws about 12.7 amps and puts out (I believe) around 26 GPM. I haven't tried calculating this myself, but I would think that the gap is not as great as normally published for the NG vs geothermal comparison. Any ideas?

Edit: Okay, I'm going to take a stab at this, but without any thermostat setback. Just a simple comparison between open loop geothermal and a 95 AFUE natural gas furnace.

Assumption: 1Kw per ton of geothermal heat using 8 GPM of open loop water. My well pump puts out about 25 GPM and draws 3.024 Kw of power. Using a simple ratio, 8 GPM would consume 0.968 Kw. I will ignore fan power consumption because both the geothermal system and the natural gas furnace have fans--should cancel out.

For 4 tons of geothermal heat, then, electrical usage would be 4 + .968 = 4.968 Kwh. With all fees and taxes, my electricity costs $0.20 per Kwh. Therefore, 48,000 BTUH (4 tons) of geothermal heat should cost around $0.99.

One therm of NG contains 99,976 BTU. Assuming 95% efficiency from the furnace, about 95,000 BTU should be produced. In my area, with taxes and fees, NG cost is almost exactly $2.00 per therm.

Therefore, number of therms to produce 48,000 BTUH = 0.5053, and cost is $1.01. Seems like a wash to me. And this is without setting the natural gas furnace to a lower thermostat setting at night. Did I miss something or perform an incorrect calculation?

20 Comments
2024/02/06
19:38 UTC

4

Waterfurnace Series 5 with ecobee - tell me about the good and the bad

I have a Waterfurnace Series 5 with a Honeywell Vision Pro thermostat. I don't really care for it. The quote I received to install symphony is wildly expensive, but I want energy monitoring and the additional control that an ecobee would offer over the Honeywell. I've found a few other posts from people that are using an ecobee on a Series 5 so clearly people are doing this. I have not found reports of problems using an ecobee aside from a few that appear to be poorly done installations.

I'm aware that Ecobee only supports up to two stages of heating and cooling, so I'm curious to hear from people that are using an ecobee if you dropped one of those stages or if you chose to wire in an on time delay device in between the second and third stages.

The circuit board on my Series 5 is fried so I had a tech here yesterday. He ordered the replacement part and will reinstall when it comes in. He said he has installed several ecobees and wouldn't have any reservations using one himself on a Waterfurnace. He did tell me to get the "premium" model but when I look at the difference between the premium and the lite there doesn't seem to be any difference in thermostatic controls. The premium has a bunch of smart home features (security, etc) that I don't need. It also supports some additional HVAC controls (humidified, dehumidifier, ventilator) that we don't have. I have an ecobee3 lite currently from my previous home so I would plan on just installing that instead of the premium model unless I'm missing something.

TLDR - If you installed an ecobee on a Waterfurnace, which specific model did you choose and why? How did you install using an on time delay device or drop one of the heating stages? What has been your overall experience with ecobee and WF?

5 Comments
2024/02/06
16:53 UTC

2

My discharge well is overflowing constantly

When we purchased our house 5 or so years ago it came with an open loop well to well geothermal system. I noticed the well overflowing after heavy rains or times when I assumed ground water was high. Now it seems to be overflowing almost constantly when system is running. My question is what do I do next and what specialty should I call? Do I call a plumber or a well driller? Is it possible the well just needs to be cleaned or is it likely it has failed and needs to be redrilled? I realize it is impossible to diagnose over Reddit but any advice on where to start or possible causes would be greatly appreciated Thanks!

3 Comments
2024/02/06
15:14 UTC

3

Waterfurnace 7/5 vs Hydron

I am hoping to get some feedback in order to make a more informed decision on new system. I currently reside in a 2700sqft house in zone 6a/b built in 88 with plenty of air sealing and insulation improvements that need to be made (and are in the works). My current setup is a NG ducted furnace from 06 that has significant corrosion in the electric box from a plugged bleeder and a blower fan on it's last leg. The air conditioning I think may be original to the house and still functioning, I upgraded the coolant last year in order to get it topped off again.

I have been researching all available options which included geothermal. I got a few quotes and they all seem to recommend the 5 ton WaterFurnace 7 series. I have plenty of land to put a horizontal fields so there's no issue with that. My indecision came from the lack of comparisons online. Both companys also offer Hydron systems so I got a quote for all three. Here are the approximate quotes after taking off the state grant offered but before tax credits which for reference is $5k state + 30% Fed.

  1. 5 ton WF Series 7 with desuperheater, UV filter, 1 zone = $36k
  2. 5 ton WF Series 5 with desuperheater, UV filter, 1 zone = $33k
  3. 5 ton Hydron YTO 060 with desuperheater, 1 zone = $33.8k

From what I understand, the Series 7 gains efficiency through it's use of the variable speed compressor but they lock you into their technology ecosystem. I have an ecobee thermostat linked up with a local home assistant server so the closed system was a con in my mind. Not even mentioning the $1000 price tag for their thermostat. Does anyone here have an opinion on these systems and/or have experience with more than one of these systems? Thanks!

12 Comments
2024/02/05
16:58 UTC

1

Apprentice help.

Hello! I have a 5 series horizontal upflow package unit. It’s on a well system I think. We replaced the old envision system. And was wondering if anyone has any experience wiring up a dehumidifier and humidifier. With an inline hot water coil for emergency heat? The system is a communicating system and has a brand new intelli zone board,dampers, and thermostats. It operates on a two zone system with its own 2 pump flow center. If anyone has any tips to set it up it would be appreciated! Thanks in advance!

1 Comment
2024/02/04
05:47 UTC

3

Waterfurnace desuperheater

I’m going to relocate my water heater and desuperheater in my basement. Is there any issue with air getting into the series 7 or can it tolerate it without issue?

I imagine it’s fine but thought I would ask.

12 Comments
2024/02/04
02:13 UTC

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