Geothermal heat pump

[Showkey]

^^^^^^^^^Agree …….would like to check the math on any electric vs gas. Even heat pump did not beat NatGas until this recent blip in Natgas pricing.
Current Nat gas is ,52/therm. It’s been as low as .18/therm witha a blip to .95/therm last winter.

 

[American Locomotive]

When he said gas, he must have meant propane.

 

[u3b3rg33k]

My Barndominium is 3000 SF with 15’ ceilings. Inside I have carved out 400SF as a two story apartment. I’ve already run 1/2” pex in the floor and am ready to buy the rest of the system.

Propane was the initial plan, but the prices are outrageous. Can anyone help me design a geothermal system that I can heat DHW, heat a closed floor loop for my radiant system AND provide AC just on the apartment side? Oh, and I’m on well water.

Maritime Geothermal has what you are asking for:


EMWT- HACW in 3-6 ton sizing. gets you cold water and hot water at the same time, with the balance going to/from the loop.

Commercial Geothermal Heat Pump | Maritime Geothermal

The Commercial geothermal heat pump is increasingly being used in schools, nursing homes, medical centres, town halls and farmers' markets.

www.nordicghp.com

just figure out your loads

^^^^^^^^^Agree …….would like to check the math on any electric vs gas. Even heat pump did not beat NatGas until this recent blip in Natgas pricing.
Current Nat gas is ,52/therm. It’s been as low as .18/therm witha a blip to .95/therm last winter.

i never cared what the price was until winter, when it goes way up. until now. now it's way up and I've barely used any fuel. gonna be a fun winter.

 

[CDPLUCKER]

i have been in my new house a little less than a year, i love my geothermal system.

1) it is quiet, no outside unit making a bunch of racket.
2) low energy bills, I average about 1/2 of my old house,
3) it was an interesting project, as an engineer I love the idea of it.
4) all of the equipment is inside in one box, no refrigerant lines etc. just the water lines going outside
5) my dealer was a very technical guy, he understood COP, basic thermodynamics etc. really understood manual J calculations etc. all the traditional HVAC guys just did not really understand that stuff
6) the difference in cost was not really that high when you factored in the the tax incentives , a traditional system was quoted $15000, the geothermal was $25,000.. so $10,000 differnce, but I got like $5000 back on my taxes so the delta was only, $5000 and the I believe it will pay back in 5 years or so
7) i have desuperheater, so i get essentially free hot water in the summer and a heat pump water heater in the winter.
8) they are really not anymore complicated than a regular heat pump, just different


It is really great

 

[yeldogt]

i have been in my new house a little less than a year, i love my geothermal system.

1) it is quiet, no outside unit making a bunch of racket.
2) low energy bills, I average about 1/2 of my old house,
3) it was an interesting project, as an engineer I love the idea of it.
4) all of the equipment is inside in one box, no refrigerant lines etc. just the water lines going outside
5) my dealer was a very technical guy, he understood COP, basic thermodynamics etc. really understood manual J calculations etc. all the traditional HVAC guys just did not really understand that stuff
6) the difference in cost was not really that high when you factored in the the tax incentives , a traditional system was quoted $15000, the geothermal was $25,000.. so $10,000 differnce, but I got like $5000 back on my taxes so the delta was only, $5000 and the I believe it will pay back in 5 years or so
7) i have desuperheater, so i get essentially free hot water in the summer and a heat pump water heater in the winter.
8) they are really not anymore complicated than a regular heat pump, just different


It is really great

It's all about the field ...... if you can get the field installed for a decent price they can work financially.

In my preferred area in PA w/o natural gas -- with all the shale and limestone the cost to dig the wells is just to great .... easy 20k each (per ton). Hard to make the numbers work even at 3T of cooling. As you go north the need for more heat works against you in a problem field area.

The other factor is the increasing efficiencies of the air to air systems .... especially mini-splits. They are getting closer to the cost of geothermal. The cost to pump water has dropped with the new efficient pumps ... that was a factor with older systems. Cost to pump water was more than cost to move air. In the end -- it's really just math. air to air and geo are the same technology -- except what is used to change the temp of the condenser.

In an easy field area with a big space and not all that efficient dwelling the geo has a greater chance of payback. As you get efficiencies in the building and especially in a more mild climate .... it's hard to make the numbers work.

At my new place in PA w/ radiant heat I would have like to have a air to water heat pump ... they are just not available in the USA in any numbers that I feel comfortable getting. I did pipe my boiler and radiant system in a way that it will be easy to add should things change. With only propane available using the ducted system (that had to be installed for AC) is actually cheaper to run at many times in the winter .... it's just not as nice as having the floor on.

Geo equipment is a bit more $$ and there are fewer makers .... seems to be as long lived as other products

 

[My Old Tools]

From the 70's to the present I do HVAC work, to this day I just don't understand what the advantage is of going with geo thermal heat pumps. Heat pumps in my simple world is a pain on its own, much less adding geo to the equation. I don't think that there will be a trained HVAC person around the corner when repairs are needed. Nor will parts be that ready available, plus dealing with water that will also require some attention and finding parts for HP alone may also be problem. I think that HP's work maybe to 35* OA temp? Then again, I don't embrace systems that only few homeowners will have. If its so great why don't more homes/garage's have them? I confess, I don't know that much about geo thermal systems, but I have installed several HP's with aux heat as backup and during cold days the aux heat was on. Just saying that maybe need to look into future say 5 yrs from now.

I think you are a bit behind the times. Heat pumps are one of the most common forced air heating and cooling systems.

 

[My Old Tools]

I've been looking at geo as well. I have one advantage, a 50 acre lake 20 yards downhill from the house. Using a lake plate hung under my T dock in 8-10 feet of water, i should have a fairly economical install. Our lake averages about 45 degrees surface temps in the dead of winter, warmer at depth, and my current system turns off the heat pump and burns propane at anything near freezing. In summer the lake should be no more than 80 degrees at 8 feet, likely less since we have some springs. With Texas summer temps running over a 100 degees for weeks at a time, a 45 SEER Waterfurnace might just pay off. We're heating and cooling 3780 SF some of the time, down to about 2200 SF when part of the house is shut off, and we have lots of glass. Currently have either two 3 ton units or a 3 and a 2 ton. Added 14 inches to the attic last year on top of 6-12. Lots more numbers to crunch, but summer bills in the $300-450 range and winter using $1500 in propane (at $2.30 a gallon, but it has doubled since then), its looking better. I think it may have a better payoff than solar power generation.

 

[FrancisJ]

Have used geo-thermal at many of my locations in the Mid-Atlantic states (NC, VA, etc) . Units from Florida Heat Pump, Bosch (they bought Florida Heat Pump out 10 years ago), latest is Geostar (this recent 2022 installation was $10K and it's a Magnolia Plus 2 Stage (5.0 Ton) Vertical, Top Discharge Deluxe High Efficiency Heat Pump (20.0 EER) (4.0 COP) w/ Free Hot Water. This latest install is open loop ----deep aquifer well in, discharge out to 1.5 acre pond WITH OVERFLOW TO ADJACENT STREAM as they pump 100s of thousands of gallons annually. There is NO question these open loops are FAR more efficient than closed loops, either "well to well" water closed loop or "antifreeze" based ground loops. I keep engineering, cost records on energy consumed, thermostat (NEST) feedback /learning and know the efficiency differences , have the data to prove. "Ice Cold" air during summers, "HOT" air during winters --- unlike the vast majority of air based heat pumps.

All this "travel" 300 ft from the well/aquifer, into/thru the geo-thermal and 500 ft out to the pond is done only by the well pump. Back at the pond, when the system's running there's typically a 12" to 18" "shooting stream" of water (aerating part of the pond). Any disruption to this loop and you'll have to bleed to preserve its integrity, flow.

I recommend not using a (shallow) ground water source as they'll empty those out quickly --- only way to go is into aquifers (in my area that's 200 plus feet deep on the well).

They are CONSIDERABLY better than air based heat pumps both in winter and summer as they're drawing constant 55 degree well water (for heat exchange) and generally pay for themselves in less than 10 years --- that along with Fed Tax Credits and it's been a no brainer and closer to a 5-7 year pay back. Off-grid Solar paybacks are considerably longer (have these too).

These units will provide all the free hot water you'll use, need during the summers. Won't get much in Winter. I have a hybrid air-based (GE) water heater and it rarely, if ever comes on from March-October.

Life span on these units is 12-20 years --- generally compressors first (5-9 years), electronics similar life span, coils, capacitors (e.g. run), controllers, etc ditto. Very little maintenance --- same refrigerant (R-410A) as air based heat pumps, onboard filter, carefully (static free) clean off electronics, other cleaning and that's it.

Your overall costs (given the floor installation) will be on the higher end. Since you only have a well, you'll end up with a closed system which places that now either warmer or colder water used right back where it came from ----which is roughly 25%-35% less efficient than an open water-based loop.

If you go ground loop the (typically used) calcium chloride (antifreeze) will break down, become less effective over time and you'll need a cupro-nickle heat exchanger as it's highly corrosive. Other antifreezes (methanol, ethanol, ethylene glycol, propylene glycol) each have their own properties (e.g. viscosity, flow, etc) so you'll have to compare. ALL so-called "extended life coolants" have finite lives (own heavy equip and experience that frequently) so you'll need to drain, refill these ground loops systems periodically -- that process doesn't really get everything (like cars, trucks, tractors, equipment, etc) so you're constantly sliding on the efficiency scale - recirculating "old" antifreeze.

Ground loop closed loops obviously have the advantage of no water consumption, but are expensive installs.

Many HVAC techs are familiar with these geo-thermals (if they have commercial customers) -- they're actually relatively simple to understand, fairly easy to diagnose, straightforward to repair. Several manufacturers provide hard wired bus-based diagnostics to their geo-thermal "mother boards" / "controller boards" ... I have mine 802'd off the geo-thermal VFR direct to my laptop which I use with other "smart home" tools. I "OBD" it periodically, wirelessly..........sorry 'Mr Maytag" repair guy (HVAC Techs) -- don't need em (unlike John Deere who is sticking it to us with crappy dealer-only OBD).

 

[yeldogt]

Have used geo-thermal at many of my locations in the Mid-Atlantic states (NC, VA, etc) . Units from Florida Heat Pump, Bosch (they bought Florida Heat Pump out 10 years ago), latest is Geostar (this recent 2022 installation was $10K and it's a Magnolia Plus 2 Stage (5.0 Ton) Vertical, Top Discharge Deluxe High Efficiency Heat Pump (20.0 EER) (4.0 COP) w/ Free Hot Water. This latest install is open loop ----deep aquifer well in, discharge out to 1.5 acre pond WITH OVERFLOW TO ADJACENT STREAM as they pump 100s of thousands of gallons annually. There is NO question these open loops are FAR more efficient than closed loops, either "well to well" water closed loop or "antifreeze" based ground loops. I keep engineering, cost records on energy consumed, thermostat (NEST) feedback /learning and know the efficiency differences , have the data to prove. "Ice Cold" air during summers, "HOT" air during winters --- unlike the vast majority of air based heat pumps.

All this "travel" 300 ft from the well/aquifer, into/thru the geo-thermal and 500 ft out to the pond is done only by the well pump. Back at the pond, when the system's running there's typically a 12" to 18" "shooting stream" of water (aerating part of the pond). Any disruption to this loop and you'll have to bleed to preserve its integrity, flow.

I recommend not using a (shallow) ground water source as they'll empty those out quickly --- only way to go is into aquifers (in my area that's 200 plus feet deep on the well).

They are CONSIDERABLY better than air based heat pumps both in winter and summer as they're drawing constant 55 degree well water (for heat exchange) and generally pay for themselves in less than 10 years --- that along with Fed Tax Credits and it's been a no brainer and closer to a 5-7 year pay back. Off-grid Solar paybacks are considerably longer (have these too).

These units will provide all the free hot water you'll use, need during the summers. Won't get much in Winter. I have a hybrid air-based (GE) water heater and it rarely, if ever comes on from March-October.

Life span on these units is 12-20 years --- generally compressors first (5-9 years), electronics similar life span, coils, capacitors (e.g. run), controllers, etc ditto. Very little maintenance --- same refrigerant (R-410A) as air based heat pumps, onboard filter, carefully (static free) clean off electronics, other cleaning and that's it.

Your overall costs (given the floor installation) will be on the higher end. Since you only have a well, you'll end up with a closed system which places that now either warmer or colder water used right back where it came from ----which is roughly 25%-35% less efficient than an open water-based loop.

If you go ground loop the (typically used) calcium chloride (antifreeze) will break down, become less effective over time and you'll need a cupro-nickle heat exchanger as it's highly corrosive. Other antifreezes (methanol, ethanol, ethylene glycol, propylene glycol) each have their own properties (e.g. viscosity, flow, etc) so you'll have to compare. ALL so-called "extended life coolants" have finite lives (own heavy equip and experience that frequently) so you'll need to drain, refill these ground loops systems periodically -- that process doesn't really get everything (like cars, trucks, tractors, equipment, etc) so you're constantly sliding on the efficiency scale - recirculating "old" antifreeze.

Ground loop closed loops obviously have the advantage of no water consumption, but are expensive installs.

Many HVAC techs are familiar with these geo-thermals (if they have commercial customers) -- they're actually relatively simple to understand, fairly easy to diagnose, straightforward to repair. Several manufacturers provide hard wired bus-based diagnostics to their geo-thermal "mother boards" / "controller boards" ... I have mine 802'd off the geo-thermal VFR direct to my laptop which I use with other "smart home" tools. I "OBD" it periodically, wirelessly..........sorry 'Mr Maytag" repair guy (HVAC Techs) -- don't need em (unlike John Deere who is sticking it to us with crappy dealer-only OBD).

More and more places don't allow open loop ... for good reason imo. pumping from an aquifer and dumping at the surface is not good ..... especially with the amount of water they use.

 

[gba2331]

More and more places don't allow open loop ... for good reason imo. pumping from an aquifer and dumping at the surface is not good ..... especially with the amount of water they use.

Yeah, this seems like a really bad idea long-term.

 

[FrancisJ]

Yeah, this seems like a really bad idea long-term.

I agree about the open loop, aquifer, but from a consumer's biz point of view --- it's a fantastic pay back, no brainer as the system is one of the best, if not the best, for efficiency, cost, recoupment. I know of no local municipalities prohibiting open loops in these parts of the Mid Atlantic.

 

[yeldogt]

I agree about the open loop, aquifer, but from a consumer's biz point of view --- it's a fantastic pay back, no brainer as the system is one of the best, if not the best, for efficiency, cost, recoupment. I know of no local municipalities prohibiting open loops in these parts of the Mid Atlantic.

There are restrictions on LI out east and also in bucks and chester counties (PA) .... It comes up in NJ and from what I have been hearing ... it may start. we re just taking to much water and having systems that inject water back into the ground is not a great idea IMO

 

[u3b3rg33k]

More and more places don't allow open loop ... for good reason imo. pumping from an aquifer and dumping at the surface is not good ..... especially with the amount of water they use.

I agree about the open loop, aquifer, but from a consumer's biz point of view --- it's a fantastic pay back, no brainer as the system is one of the best, if not the best, for efficiency, cost, recoupment. I know of no local municipalities prohibiting open loops in these parts of the Mid Atlantic.

I dunno if I buy that open loop is more efficient than closed loop. maybe if your closed loop is way undersized, but even for vertical boreholes, pumping cost is WAY lower with closed loop than open loop. you have to pay to lift the water with open loop, with closed loop the forces net out and you just pump against friction. closed loop keeps the loop fluid (and pumps, HX) isolated from contamination as well.

 

[reader2580]

Minnesota outlawed new open loop systems several decades ago and all existing systems were supposed to be turned off a few years ago.

 

[American Locomotive]

Yeah, open loop geothermal pumping precious ground water into ponds on the surface is the stuff of environmental nightmares. What a collosal waste of good water.

I don't see why open loop would be any more efficient than a properly designed ground loop.

 

[theoldwizard1]

The one thing I would want on any geothermal system is a temperature probe for the water leaving the house and a second one for the water returning.

Water Furnace (are they still in business ?) sold a lot of ground loop systems in the Midwest. People did not like them because during extreme!y cold winters they did not make enough heat. Either the compressor/condenser/evaporator were under sized or the ground loop was undersized.

 

[yeldogt]

The one thing I would want on any geothermal system is a temperature probe for the water leaving the house and a second one for the water returning.

Water Furnace (are they still in business ?) sold a lot of ground loop systems in the Midwest. People did not like them because during extreme!y cold winters they did not make enough heat. Either the compressor/condenser/evaporator were under sized or the ground loop was undersized.

one has to size the well loop properly and then install it correctly. Grout it in properly so the heat transfer can occur.

In some areas where you have enough land the horizontal will work as well.


with a lot of rock it's often best to set it up to get you close to the full load then have some type of backup.... at 20k a well that was what they told me would be best. do three wells for three tons and add something for backup on the really cold days, $20k a well buys a bit of backup

 

[theoldwizard1]

In some areas where you have enough land the horizontal will work as well.

The problem with horizontal loops is that if the heat transfer calculation is wrong, frequently there is not enough land for a second loop.

 

[u3b3rg33k]

one has to size the well loop properly and then install it correctly. Grout it in properly so the heat transfer can occur.

In some areas where you have enough land the horizontal will work as well.


with a lot of rock it's often best to set it up to get you close to the full load then have some type of backup.... at 20k a well that was what they told me would be best. do three wells for three tons and add something for backup on the really cold days, $20k a well buys a bit of backup

I can see justification for putting in a relatively small heat strip. Personally, I think heat strips should "all" have a temp controller set to 140F or something, so they only run as "hard" as they need to in order to provide adequate discharge temp. not the "lets dump 20kW and crank fans to max" **** that is common on non-communicating systems. temp controllers and zero-crossing SSRs are not that expensive.

 

[yeldogt]

I can see justification for putting in a relatively small heat strip. Personally, I think heat strips should "all" have a temp controller set to 140F or something, so they only run as "hard" as they need to in order to provide adequate discharge temp. not the "lets dump 20kW and crank fans to max" **** that is common on non-communicating systems. temp controllers and zero-crossing SSRs are not that expensive.

The missing link is the air to water in areas w/o natural gas -- for my projects anyway. I like radiant floors .....

With forced air heat it's just math. I guess it's just my bad luck ... every project where NG was not available there was some issue that made GEO problematic. Most have been in PA .... but, I did one north of Boston and one in Maine.

in my normal area of PA there is so much rock in some areas the installers are forced to have systems designed for everything except the worst days

 

[u3b3rg33k]

The missing link is the air to water in areas w/o natural gas -- for my projects anyway. I like radiant floors .....

With forced air heat it's just math. I guess it's just my bad luck ... every project where NG was not available there was some issue that made GEO problematic. Most have been in PA .... but, I did one north of Boston and one in Maine.

in my normal area of PA there is so much rock in some areas the installers are forced to have systems designed for everything except the worst days

I have a friend in CT who lives in a no-NG area. he used to complain a lot about the jan/feb bills. I hooked him up with a smarter thermostat, (heat pump aware, temp based strip heat lockout, "intelligent" recovery, etc). paid for itself the first cold month and then some. now he has a higher end inverter split system, and his bills are now lower than mine, and I have gas.

as for air-to-water, maritime geo has a few units I like the look of. their ATW series is 2-6 ton, and the ODU is just a coil, compressor is in the indoor unit. I like that a lot.

other options are chilltrix, or the sanden CO2 unit. the latter is targeted at DHW, but I don't see a reason you couldn't use it for space heating with a mixing valve. they claim 15k BTU and a COP of 3 or so with 150F discharge water temps in single digit weather.

 

[yeldogt]

I have a friend in CT who lives in a no-NG area. he used to complain a lot about the jan/feb bills. I hooked him up with a smarter thermostat, (heat pump aware, temp based strip heat lockout, "intelligent" recovery, etc). paid for itself the first cold month and then some. now he has a higher end inverter split system, and his bills are now lower than mine, and I have gas.

as for air-to-water, maritime geo has a few units I like the look of. their ATW series is 2-6 ton, and the ODU is just a coil, compressor is in the indoor unit. I like that a lot.

other options are chilltrix, or the sanden CO2 unit. the latter is targeted at DHW, but I don't see a reason you couldn't use it for space heating with a mixing valve. they claim 15k BTU and a COP of 3 or so with 150F discharge water temps in single digit weather.

I keep reading that they are coming -- the air to water. It seems that Spacepac has a new system --- The guy I know that does space pack has no information on it. THO or Fine homebuilding had one recently -- it was part of a larger system and the cost was way above what would be reasonable for the vast majority of people.

The idea of a self contained unit with only some type of glycol going to an internal heat exchanger seems like a nice setup. In a big house the internal compressor is fine as you have the space to hide and quiet the compressor -- I'm sure there is longevity with that set up.

My new studio has about a 15k heat cooling load. The spacepack seems to circulate water .... that could do both a hot floor and some type of fan coil for AC ( They have things that look like a mini)

 

[theoldwizard1]

The missing link is the air refrigerant to water in areas w/o natural gas -- for my projects anyway. I like radiant floors .....

These are sold by the major manufacturers OUTSIDE OF THE USE !

Really not that difficult. Requires a refrigerant to water heat exchanger (not hard to find) and then some kind of temperature sensor/feed back to the control unit.

 

[theoldwizard1]

I keep reading that they are coming -- the air to water.

Mitsubishi NZ ! Now you can combine a Multi Room Air Conditioning System with hot water heating!

 

[yeldogt]

Mitsubishi NZ ! Now you can combine a Multi Room Air Conditioning System with hot water heating!

They have them In SA as well ..... I don't have one as capetown is fine with simple minisplits and solar WH.

Spacepack has some new system ... the problem is the install. lots of equipment