using geothermal to supplement bailers

Chris_51

I've heard that Michigan is a poor state for solar.

If yo find some schematics, I'd appreciate it. I figure I have a 2-stage system now, so adding geo would just be a 3-stage. heating the pool would be nice too.

Chris_51

using geothermal to supplement boilers

I was chatting with a neighbor who used to work for the local power company yesterday. He said a few people in the area had installed geothermal systems and were happy with them. The cost is still pretty high, but my gas bill was about $3,100 last year. It was $4,100 before I upgraded the boiler. This includes winter heating and some use on the pool in the spring and fall.

I guess if I could save $2,000 a year, over 10 years, I’d have some $$ to play with for such a system.

I spoke with a local geothermal contractor and they say the would prefer to take the boilers out. I’m not so sure that is a good idea at all. I was figuring that I could add the geo heat into the loop and then my boiler logic would just fire the boilers less often. I built 4 Y-s into the loop for future expansion. Has anyone done anything like this?

My heat system is an old (1928) hot water system. It a single pipe system, with an extra loop for the expanded back of the house. It was originally a gravity system, but not has pumps. 90% of the time my boiler logic reads under 120F, which I understand is the max for geothermal. I’m not sure how much heat a geo system could produce though.

If this is a crazy idea, I’d like to forget about it. If it has merit, I’d like to do some research.

Unknown

It's generally either-or unless your water temp is under the geo max and you have a low temp boiler.

Rich L.

Geo

Chris I have seen a home done with geo and an electric boiler. The Geo was sized to handle around 90% of the load and the boiler kicks in the last little umph for design temps. The added benefit for you would be summer time pool heating by the heat being removed from the house when in cooling mode.

Ed_26

Combo systems

Solar? - no digging - pool heat in summer/shoulder seasons.

singh

I'll look

for some schematics which shows combo boiler and GSHP.

But I agree, go with solar thermal panels instead, plus you get bigger tax credits currently, and virtually nothing for geo, unless it was a commercial install/

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Jeff Elston_2

Geo

Chris, you should do it, I just finished three days of Geo schooling to get my IGSHPA certification and the stuff is for real.

The most important thing is to size and install properly. The most important thing is to size and install properly. I should say it again it cannot be stressed enough. If it is then you will get very nice savings.

The IGSPHA instructor built his own system a number of years ago and has been running very thorough data logging which he shared with the class. He lives in South Dakota and pays in a year what I pay in a month here in Phila. of course there are more variables but you get the piture.

If you need some good info let me know.
Good Luck

Chris_51

Jeff - On the local utility page they say they provide a special rate for the geo power. That seems a bit suspicious, since the special rate seems to account for the efficiency. What is to keep them from raising it down the road?

schiller

Chris, I've put in a couple of GSW units w/ electric boilers as back up. Your system should be able to be retro-fitted. I've proposed your type of system a few time over the last few years but the up front cost has kept people from going the route. if you plan on the geo being the first stage of heating and you boiler being the 2nd stage sizing the geo the building load in not so important. if you are thinking of an open loop system ( your least costly option)then it would be very easy. if your are planing on a closed loop system then sizing and properly installing the loop field is a very important task. I'm in southern Mi and we are finding alot of customer who are looking for both lower operating costs and "green" types of buildings are looking at the geo products

Wayco Wayne_2

What if...

You did the geo and boilers the same as a dual fuel and had a switch over point based on outside temperature. What temps so you need for your heat emitters. Geo's can usually only get 125 F. WW

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Tom Blackwell_2

There is no reason that either geothermal or an air source hydronic heat pump cannot play together. When the load becomes greater than the heat pump output, then an either/or switch can be made, based on either system requirements or outdoor air temperature. My house near Atlanta has a built-up water source heat pump utilizing swimming pool water and is used in summer and the shoulder months untill the pool water gets below 50 degrees. At this point the switch is made to an air source heat pump. Last stage is a conventional hw boiler, only used when the outdoor temperature is below 45 degrees. Emitters are radiant slab, dhw hx, and hydro air. Our West Tennessee residence has a water source heat pump fed from a well, sized for the heating load of 45,000 btuh. Backup heat is electric. The only caveat for use of a geothermal or as heat pump in conjunction with a standard hydronic system is the logic to switch sources when higher temp's are needed. The lower the design hot water temperature at winter design, the better - more emitter=good.

Craig R Bergman

Special Rates

The reason they give special rates to "all elcetric" homes is energy contracts. Electric providers(not producers) need to predict how much energy their customers need for the year. They then contract for the estimated amount, if they fall short and have to go to the open market they take it in the shorts on the cost. A home that is "all electric" is very easy for them to predict energy usage.

hot_rod

Keep in mind, it is electric heat

and I suspect electric rates will rise as the gas and oil prices are.

Germany has a big push to switch from oil to geo. New powerplants will need to be built to make this happen. That takes us back to the coal or nuke discussion when electricity is considered as a heating source.

If electric heat is your option then heat pumps are the best, current way to leverage that fuel.

A small gas powered generator keeps me in heat and hot water when we experience power outages, with my wood and lp fired equipment. A fairly large generator would be needed to power a heatpump.

Pros and cons both ways. Dual fuel, or tri fueled systems seem to make some sense

hr

Craig R Bergman

Keep in mind

A properly designed GSHP will run a COP of 3.5 to 4.5,give or take a little. For every one dollar of energy you put into it, you will get 3.5 to 4.5 dollars of heat energy out of it. I don't know of any other equipment that is 350~450% effeicent(sp?).

Bergy

Chris_51

so adding a separate service to get this rate isn't really the intention of the discount - or so it seems.

Chris_51

It makes sense that you get more efficiency when the heat pump isn't stressed to the max. My system is converted from a gravity system, so it has a ton of water (1000 gallons or so). It works a lot better when it slowly changes the water temps. In fact, the setup on the boiler logic for setting the nighttime mode doesn't really work as designed. They want a 6 degree drop at night, which basically shuts it off completely all night. Then in the am it tries to heat up, but takes a while to get going again.

I worked around this by simulating some gravity movement with one pump so the loop always gets a little heat. Then I use another pump connected to a stat to get things really moving. It seems to work well.

With this in mind, I envisioned the geo as the slow heat, and the boilers as the kickers. Instead of switching from one to the other, it seems that using both until a certain outdoor air temp, then cut the geo completely wold be best. If the logic doesn't need the second stage, then its all geo. If it needs it to level things out, then I'm good too. I think my boiler logic could handle that as it stands.

Also, I do have my generator setup up to run the boilers and the fridge and a few outlets in a power outage.

Craig R Bergman

Seperate service

If your utility operates like ours, the seperate service is for the Geo(or any electric heat device)ALONE. October thru March we get 4.8 cents Kwh to run the GEO.

Bergy

Rich L.

Reduced rate

Actually anything tied to the Comfort System. This includes controls, pumps, resistant (back-up), etc can all go on the reduced rate panel.

Chris_51

If your in Michigan, shoot me an email. chriscpmtmp@aol.com