Gasification Boiler vs. Geothermal Closed system

[starksb]

I am planning on building a 4000 house that will be an energy star house. I am having problems on which one to go with. Geothermal will do my a/c and heat. Plus I do not know what my electric bill will be with geo. I do not have a problem cutting wood. Plus if I go geo I will have to heat my shop with something different. If I go with a Wood boiler then it will heat my house and shop. Please let me know what you are thinking.
The pros and cons
Thanks for all your help.
This is a great site and I have learned a lot.

 

[Nofossil]

If I had a good source of water (adequate flow rates, in particular) I'd be inclined to use a gasification boiler as my primary heat source and geothermal as my air conditioning and backup heat source. Massive heat storage of course, heated by solar hot water panels and the heat pump during the summer.

 

[oldmilwaukee]

Just a thought... if you're in MI, and using geothermal solely for A/C, you can probably get by with a lot smaller geo system, since it will be sized for cooling loads and not heating loads. Take the money you save and put it toward a gasification boiler. The smaller geo system (or even a simple air-sourced heat pump) can probably heat your house in the fall and spring.

I have a boiler (installed) and will have a 4 ton geothermal system (to be installed). The wells are drilled, ground loops installed, 2ton units are sitting in the basement, installer supposed to show up any day now to finish the job - at least he hasn't asked for a dime yet! I am off the grid. My plan is to run the geothermal for all of my needs in the spring, summer, and fall. I don't have enough solar power in the winter to even come close to covering my heating needs with the geo in the winter. (especially when snow is on the panels!) It's 25 degrees outside and 69 degrees inside thanks to a load of wood I put in the boiler this morning.

Got any quotes on the geothermal system yet? They can make boilers look cheap. :0

 

[starksb]

I got a price on geo that was 22,000 and I think a boiler would be 10,000 to 15,000 with storage. Plus with a boiler I would have to have a forced air system so that I can have
a/c and as a back up for heat if I leave the house.
Thanks

 

[Nofossil]

If you're planning new construction, look carefully at the option of radiant floor heating. It achieves comfort at lower temperatures (and therefore lower heat losses) than other heating methods, and is generally considered to be FAR superior to forced hot air for heating. Radiant also allows you to get much more usable heat from solar and storage, since it will work with cooler water.

For my A/C, I have small wall-mounted evaporator / fan units that are quiet and reasonably unobtrusive. That may be an option that allows you to avoid the ductwork.

 

[DaveBP]

Have you looked into mini-split air conditioning systems? Compressor outside and no ductwork. One of these for AC and a gassifier/storage/radiant floor system for heat and whatever solar is easily available might be about as efficient as you can get and cost no more than a geo setup.

 

[starksb]

Where can I get some info on your A/C units and I have 4000 ranch house, so would I have to have a lot of these units around the house.
Thanks

 

[603doug]

We install the wells and pump systems for geo systems here in NH and the system I am aware of run into the 4 to 10 ton range. With the added depth to the well or wells for close loop(better system) and increase size of pump plus heat exchangers etc. the price range is $30000 to WOW. You could put one hell of a boiler in, plus solar tubes and electric air cond system. I debated on doing it instead of a wood boiler but even installing a system myself it was $20000 plus a $300 a month electric bill. If I did not have the source for wood I might of gave it more consideration. Plus here in NH the three days you need air conditioning I probably would be cuttin wood.

 

[Nofossil]

Where can I get some info on your A/C units and I have 4000 ranch house, so would I have to have a lot of these units around the house.
Thanks

Mine are the 'split systems' referred to above - 18kbtu Carrier and 8kbtu Mitsubishi in my case. I assume that since the compressor is separate, you could use the evaporator/fan units with a heat pump as the compressor. I cool a 3500 square foot house with two units. I really need a couple more really small ones for two of the bedrooms, though. I live in Vermont, so the heat load isn't really oppressive most days.

 

[henfruit]

i have the water supply.true artesian dumping 10 to 15 gals a minute into the brook next to the house. i get 40# at the well head. almost dont need a pump. i would not want that high of an electric bill each month. 175 .00 is high enough.

 

[mbcijim]

https://www.hearth.com/talk/threads/34014/

I started the thread attached. I'd spend some time reading through it, technical, but it might have some info you are looking for.

Long story short is I have a 3,500 sft house + 2,200 sft basement.
I just got my electric for the geothermal down to about $200 for February, not including the basement, which got turned on yesterday. But basement stays at 60 without doing anything, so not expecting a big bump.

I have two units, 7 tons total, install cost was about $34,000.

Would I do it again? Not sure. My other choice would be wood gasification. I think you're asking the right questions.

I think it comes down to $$$ vrs. Work.
Gasification will be cheaper. Are you, and can you, do the work of wood, for as long as plan to own the house?

 

[Wet1]

This is a simple one in my mind... geothermal. You need a maintenance free system to use while nobody is around (gasifiers still require some regular input from the HO to keep it going), plus for resale reasons you'll w/o a doubt need a maintenance free central heating/cooling system in that house... most people don't want to deal with all the work and upkeep a wood based system requires.

 

[peakbagger]

I understand why geothermal in the right application should be a winner even up north and I have talked to a few folks that have systems that think they are the greatest thing since sliced bread. Nevertheless I would have a tough time recomending them in a rural area as they are very technology dependent and barring someone who has a huge standby generator, is not something that can be run when the grid is down. Running a gasifer with a generator is one heck of a lot easier and would use a lot less gas. Granted a gasifer has a few moving parts and some controls, but an average homewoner has a good chance with the help of Hearth.com in maintaining and fixing a gasifier, whereas if there is a problem with a heat pump, the average owner is going to have to call in a skilled service tech. If you want to cut down on handling fuel (at a trade off for higher priced pellets) consider getting a maine energy systems pellet boiler once they get a dealer network out your way. Given my experience in getting a AC spilt unit hooked up in a rural area, good HVAC techs are hard to find in cold climates and they dont tend to hang around long as air condtioning in cold climates is a very seasonal business.

A well designed energy star house should not have a high cooling load and split units are hard to beat. Most of the splits have an option for heat and they are essentially an air source heat pump with a reasonable COP for a whole lot less money than running ducts and installing geothermal. My experience is that they dont require any maintenance unless they are physically damaged or the fins are clogged up.

 

[603doug]

I would check into the close loop system over a pump and dump system. The close system water quality is controlled not causing maintenance down the road because of mineral issues in raw water plugging the exchangers plus a smaller pump easier to replace. Drawbacks- a larger system and more wells or trenching.
Henfruit be careful about open discharge for your system, New Hampshire and the Feds have regs on changing surface water quality (a natural artesian well discharged is not as regulated) because of the discharge water, some times we drill two wells 1 to pump from and the other to discharge to.

 

[pybyr]

I would check into the close loop system over a pump and dump system. The close system water quality is controlled not causing maintenance down the road because of mineral issues in raw water plugging the exchangers plus a smaller pump easier to replace. Drawbacks- a larger system and more wells or trenching.
Henfruit be careful about open discharge for your system, New Hampshire and the Feds have regs on changing surface water quality (a natural artesian well discharged is not as regulated) because of the discharge water, some times we drill two wells 1 to pump from and the other to discharge to.

Be careful, too, that a second well is not done in a way that any state or federal regulator might treat as an "injection well"-- I am told that this can complicate geothermal well-type systems in some places, as regulators have concerns about the potential of contaminants being sent down into an aquifer.

I know relatively little about geothermal, other than having looked at some systems first-hand and read up on it, but the buried loop systems, for those with adequate space and soil depth, seems inherently simpler and lower cost, both up front and down the road- and seems like it'd have less to go wrong.

 

[oldmilwaukee]

Yes... what nofossil said! If you are building a new house and thinking about a boiler, you should definitely look at radiant heat. We've been living (still living there) in a double wide trailer with a heat pump for 6 years. Even when the thermometer says 73 it can still feel cold in the trailer when the registers are blowing air. Here at the house site (our new house, one mile from our trailer) where we are spending most of our waking hours, we have radiant heat floors and 69 degrees feels great. In fact 70 feels hot here and 72 can be down right oppressive! The radiant heat floors are very comfortable and the loudest sound in the new house is the fan on my computer (or fridge if you're in the kitchen). My boiler and geothermal are completely separated systems in the new house. The boiler heats only the radiant floors and the geo will heat (and cool) only through the ductwork. (actually, the geothermal and the boiler are both connected to the indirect hot water heater, but otherwise they are separate.)

 

[pybyr]

One additional thought- if one uses as wood gasifer to meet heat load, might simple deployment of cool ground water meet cooling needs without need for the complexity of compressors, etc., involved in a heat pump?

My 1830 house still derives its water supply from a gravity-flow spring 400 yards away that sends between 1 and 2 GPM of cool water to my cellar 24/7/365 (including during droughts when drilled wells have dried up). If I had much cooling load (it rarely gets very hot here, or for very long) I'd try a "redneck air conditioner" by running the spring run-off through a truck radiator + fan tied into my ductwork; as it stands now, I do aim to try running the spring overflow through a spiral copper coil+ fan in the basement, to see if it'll do the job of my dehumidifier, with a smaller electric demand.

 

[husker]

I had the same questions you had a couple years ago while planning our new 2200 sq. ft ranch on top of a full walkout basement. Because of the hot humid summers forced air was a necessity although I still may add some radiant later to parts of the house with tile (bathrooms & entry areas).

A ground source geothermal (drilling 4-5 wells) was about $20-22k. Pole barn would still need to be heated with propane or wood stove. I couldn't do a pump & dump because of the poor well situation in my area. I most likely would have went that route if it was available since we have winter rates in Nebraka that make heat pumps attractive (~$0.07 for first 1000KW then $.0424 anything above). June thru Sept is not bad either at ~$0.085 for residential.

I decided to go with an air source heat pump with electric resistance backup and wood gassifier in barn with buried lines to home. I have less than $15k in this but did some work myself and don't have storage yet. The gassifier in the barn has been great the past month or so with 75-80 temps in 0* weather. I went with this option to keep the mess out of the house, have 1 fire to tend, and still have a system that would allow us to leave home for a few days. I may still need to put a small propane or electric water heater in the barn to protect from freezing unless the sidearm in the new home will "steal" enough heat.