savings from geothermal

radmix

What is the real world savings from geothermal. It seems to me that if you add in the price of the equipment and the fact that you can only get 50* water from the ground is there a benefit. I received a call from a homeowner the other day stating that since he installed his system his electric bills went through the roof. There's a 30 amp breaker running the pumps, One for the compressors, and two to run the air handlers to deliver the heat. I live in upstate N.Y. and it just seems to cold to see any paybacks in the heating season.

Just because your not burning a fossil fuel on your property people think its efficient but theres a nuke plant or a coal plant somewhere making all of the electricity, Or am I just seeing this wrong

NRT_Rob

depends

GOOD geothermal should run COPs of 4 or 5. so take the cost of heating with electricity and divide it by 4 or 5 and there you go.



However I bet at least half the geo out there isn't "good". it's running too high a temperature, inefficiently, with grossly overpowered pumps, and maybe insufficient loop field/well coverage. Those systems might only run a COP of 2 or less. There are some real pigs out there as well.



We're using Air source and get just about an average COP of 3 or so. that's pretty good, and no dirt work, but has its own design considerations.



So usually you can save quite a bit on energy costs, "can" being the operative word. and of course, the REAL question after that is whether those savings will ever see a return on investment.



Generally, the answer is only "yes" on very large loads. But if you do cooling as well, and save a condensor/chiller, that helps, tax credits help, etc.

GW

ahh yes

The illusive "real life" cop in the north will not be over 4 unless you're a magician. Factor in lame duct systems and heating guys not knowing a lot about how loose many homes are (how many heating guys have a blower door?) , it's the recipe for shattered expectations for sure.

NRT_Rob

don't need to be a magician

4+ from geo *should* be an expectation, IMHO. I see greater than COP of 4 out of our ASHP utilizing air that is not much warmer than the coldest "loop field" temps a good geo system should ever see.



It's an expectation that, as you say, is often shattered, but that's a question of design/install competence, not the technology itself. Lots of boilers out there aren't performing to the label either, but that's not their fault.

radmix

savings for geothermal

Would a water to water system or a water to air system have an effect on the efficiency of the system. Ive seen water to air systems that have a electric coil back up for the supplemental heat or would a condensing boiler make sense. It seems to me that a hydronic heat emitter such as radiant or panel radiators would be better then a ducted system but with a ducted system you can also have the benefit of the air conditioning. Also for the domestic hot water, go for the tank less water heater of a indirect off of a condensing boiler if that's preferred

Thanks

Rich

GW

Rich

Sorry Rich were those questions or comments? Water to water is not as efficient as water to air. Now let's talk about distribution. Anyone who uses Geo with a lame duct system should be examined thoroughly. You are discussing two different topics. The same holdstrue for hw systems....although a lame duct system is much worse than an equally lame hydronic system (well. ...unless the he system is leaking that ).



Dhw..you still need backup. I always hate the use of electricity

GW

?

What's your ewt in your systems?

CMadatMe

I Ponder This Question

I've  often pondered the subject question. I'm located in the Northeast so my feelings are based on my climate.



I firmly believe you would never see the added investment payback when compared to a well designed and installed radiant and panel rad system using a condensing boiler tagged with a properly sized and insulated a/c system over the expected lifetime of each system. 

GW

ahh

I may be a more hard core hydonics man than you, maybe not. But the question must be asked: your assessment is based on today's fuel costs? Propane? Oil? No one argues the math but we can bat around the method of how the energy gets moved to keep us warm

TonyS

I can only speak of my own system

My home is 2000 square feet, two floors with low temp radiant heat and a 38000 btu heat loss at 0 degrees. I was heating with wood up until Jan 1st and then I switched to the Geo unit, a three ton water to water single stage open loop with a outdoor reset in the buffer tank. The increase in my electric bill was 85 dollars in jan and 100 dollars in feb. February reflects a new increase per killowatt. I live in Reading Pa.

CMadatMe

The Bigger Equation

You left out electricity...Is that not part of the equation? The question of payback also has to figure in on the installation of the system as a whole as well. Your peer or mine may not have the same skill set or work ethic. In the real world it's not always just about the arrow it's more about the indian. Any system is only as efficienct as the indian that installed it no matter what it's given efficiency is.

Mark Eatherton

Cash outlay...

Any time ANY one individual commodities monthly costs jumps, the consumer pays attention to it. What they are not looking at is the BIG picture. How many bucks are the passing out each month now for heating, lighting and cooling. In most cases, with GSHP, their cash outlay SHOULD be less than it was before. Not by much in some cases, but less in any case.



And this is one misconception that this particular industry (GSHP) typically tries to hide under the carpet. And if you take into consideration the inefficiency of the electrical generating plant, it's NOT so carbon neutral as they would like you to believe. In most cases, it SHOULD be much more efficient with the electricity than are direct electrical resistance heating elements.



There are a lot of problems with the loop fields not being adequately sized, causing a huge ice ball to be formed, resulting in poor operating efficiencies. In some cases, drought is causing the loop field to dry out, losing a significant amount of thermal conductivity to the heat source...



Hence, why I like to avoid horizontal loop fields, and opt for vertical bore holes instead.



Ask the customer how much their overall cash outlay has changed. Unless something is REALLY out of whack, their cash flow out should be somewhat less.



ME

zacmobile

water to air more efficient?

How do you figure that? even with an ECM blower your distribution costs are many times what it would be for water to water, also no ability to use outdoor reset witch REALLY boosts your efficiency. In our old R-22 3 ton water to water that was heating our shop it would get COP's as high as 5 in milder weather with outdoor reset & smart pump only using 10 watts to distribute it throughout the building!

NRT_Rob

seconded

while with water your return temps aren't 70 degrees like they are with air, at least not all season, you can stay pretty close and distribution energy can be fantastically less.



with proper reset control return temps shouldn't often go much over 90 though in a good hydronic/HP design.

Bob Gagnon plumbing and heating

Geo

Most people I talk to have low comfort and high electric bills. The two people that were happy with their bills and comfort, had water to water with radiant as a delivery system. Both had high ceilings and  I think the radiant advantage helped the geo systems a lot. If your getting 50% of you heat for free and it's staying low because you have radiant heat that's a great advantage.



Thanks, Bob Gagnon