dagettem
New Member
Posts:2
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| 03 May 2010 02:03 PM |
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I am currently in the process of finalizing the paper work for a geothermal system. I am going with an open loop 4-ton Carrier 50YDV049KCB 2 stage variable speed geothermal heat pump. The back up will be an electric Carrier AGL15. I got these quotes from a highly respected and well known installer and professional. I have three questions.
1.) My current system is electric baseboard heat installed 1973. During the dead cold of winter my electric bill was $700 after Christmas light season.  This was not fun. Even while coming out of winter, it was still alittle too high for my comfort ($600). I did turn off alot of the heaters in the house and ended up purchasing a space heater and put a timer on it during the time I was getting ready for work. The house has no air conditioning and the electric bill was typically around $100 during the summer. This pushed me over the edge during the winter, and I said I am going all the way after far as a heating system. What savings can be expected?
2.) I currently have a 10 gpm pump in my well. The well company spec'ed me a 20 gpm submersible pump for the geothermal system. I also asked that they spec me a variable speed pump. That was a 15 gpm. The variable speed is about $1000 more than the regular submersible pump. Is the variable speed much more economical that my savings would pay the extra $1000 off?
3.) Last question, I have an 60 gallon electric hot water tank (not even close to energy star), how does that whole system work when you tap the geothermal provide hot water? How much is it typically and is there any good websites I could check one out at?
Thanks! |
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Ona
Basic Member
Posts:189
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| 03 May 2010 03:17 PM |
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dagettem ~
I'm just a homeowner, but I suspect that the pros on this site will have a hard time helping you out without a little more info.
For example, how much you paid for electricity is not as helpful as KWhrs used. You can imagine that $700 per month where it costs 22 cents per KWH (like long island, NY) is very different than $700 per month where it costs 4.5 cents per KWH (like areas on Indiana).
In addition, I don't believe that they can do the calc's on how much the system will be used without your location (to get an idea of outdoor temperatures , delta T's) and the manual J (heat loss calc) of your home.
I can share my experience as a homeowner. I live in Upstate NY in an old home. I have a 3 ton closed loop system in a 1950 sq ft home. I have newer windows and attic insulation, but no basement or wall insulation.
Before geo, we had 84% efficient fuel oil water heat. We went through ~ 900-1000 gallons of fuel oil each year. The cost of fuel oil ranged from $2.69 - $4.00, so we were spending anywhere between $2,690 and $4,000 per year to heat our home.
After geo, we have spent $800 - $900 per year to heat our home. Furthermore, we have the desuperheater set up so we save money on hot water. I have placed sub meters on the geo system, the backup coil and the hot water heater.
Regarding your hot water question, we have a non-electrified 50 gallon water tank followed by an electrified 50 gallon hot water tank. When the geo is on we use between 1-3 KWH per day for hot water. When the geo is not running we use 9-12 KWH per day for hot water. |
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engineer
Veteran Member
Posts:2749
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| 03 May 2010 06:07 PM |
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Actually, in the case of substituting geo for existing electric baseboard heat we can very roughly estimate savings based just on the info you provide. Geo heat pumps typically operate at a real world COP of 3.0 or so; some a bit better; some a bit worse.
Using a COP of 3 and your present $600 monthly electric heat bill of $600 we can roughly project a geo heating bill of $200; in other words, a COP of 3 should result in electric cost of heating of 1/3 what you now pay.
Ona describes the optimum setup for heating water via a geo with desuperheater - 2 tanks. Ona is getting very good results from her system.
There are some sticky posts at top here and at geoexchange.org with basic information for folks beginning to look at geo. Review them and try to get answers to the questions there and we can help you with specific alternatives |
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Curt Kinder <br><br>
The truth is incontrovertible. Malice may attack it, ignorance may deride it, but in the end, there it is - Winston Churchill <br><br><a href="http://www.greenersolutionsair.com">www.greenersolutionsair.com</a>
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waterpirate
Basic Member
Posts:467
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| 04 May 2010 06:32 AM |
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A variable speed pump can solve al lot of problems commonly associated with a poor or bad water pump install. As you found out that comes at a hefty price. I just did an install using traditional pumping equipment, 11/2 hp 33gpm for a retrofit that saved the customer some serious upfront money over variable option. |
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| Eric Sackett<br>www.weberwelldrilling.com<br >Visit our Geothermal Resource Center! |
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DXpowerhouse
New Member
Posts:3
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| 04 May 2010 01:07 PM |
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You could avoid a water pump and the electricity it costs to run it by going with a waterLESS DX system. You can also achieve at least a COP of 4.0! Check out earthtoairsystems.com |
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dagettem
New Member
Posts:2
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| 04 May 2010 01:13 PM |
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I really appreciate all of your replies. It helps me alot by better understanding the efficiencies and knowledge base how this is going to help me in the future.
Ona, I will do a little research about my electric bill for you. I do live in Western PA just northwest of Pittsburgh where our temperatures are scattered. You are looking at range of teens to mid-90s during the August sun. June heat is usually around low to mid 80s. We did have a cold spell this winter with it going into the below 0s, which I know our backup electric heat would have been running during this time. Your hot water deal is probably the way we will have to go.
Curt, I appreciate you just giving some real quick guesses as far as the electric bill. Since I am young, and sometimes ignorant, my electricity habits have changed tremendously. My wife and I are very good about turning off lights and not having something on that does not need to be on. I will take a look at that page.
Eric, I will probably go the route with the variable speed. I feel in the long run it will pay for itself. This is what I was spec'ed:
Grunfos 15-SQE180 15 gpm submersible pump with smart motor
CU301 Status box to communicate with pump in well to achieve constant flow
Thanks again for all you replies! |
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waterpirate
Basic Member
Posts:467
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| 04 May 2010 01:59 PM |
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I have had some really bad experiences with the grundfos product relating to electrical supply from the provider. That unit is super sensitive to fluctuations in the supply. Both spikes and brown outs on rural supply has been detrimental to their life expectansy. If you even consider your supply to be rural "flakey" I would urge you to look at another product. Franklin electric perhaps. The cost of that c301 unit is not the whole story, the pump itself also has a computer proccessor in it, one or both proccessor is affected by the electric supply. |
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| Eric Sackett<br>www.weberwelldrilling.com<br >Visit our Geothermal Resource Center! |
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jonr
Senior Member
Posts:5341
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| 04 May 2010 05:20 PM |
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I'd look at using your existing well pump with a booster pump added at the surface. Ie, your existing pump might do 15+ gpm at 15 psi and then use the booster to get the pressure needed for household use. Pressurizing water for geothermal use to 50+ psi is quite wasteful (could double pumping costs).
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