njbillt
New Member
Posts:14
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| 25 Sep 2009 08:55 PM |
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It's a closed loop, 4/5? ton Carrier Infinty, 2 zone (one up, one down) 1700 sq ft home in New Jersey. The system has 2, 150 foot wells. His electric bill for August was $711. The contractor that installed it tried to sell me on one last summer and his heat bills last winter weren't great either. I'm glad I didn't jump. Clearly this thing is never going to pay off. I understand the theory behind geo, I just don't buy into it. The contractor told me it stores heat in the ground during the summer to be used in the winter, but in the next breath he tells me the ground recharges daily. My theory about my neighbors system is, the wells are insufficient and the heat pump is working really hard to extract heat, or in the case of summer has no place to dump heat. What say you experts? If indeed geo stores heat for the next season, is it not true that the efficiency of the thing diminishes as the seasons wears on and the capacity of the wells run out? Isn't it a little like trying to heat with an air source heat pump during the winter when the temps drop below 25, when your geo system has been extracting heat for 2 weeks and the ground is frozen solid?
Bill |
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Down2Earth Geothermal
New Member
Posts:59
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| 25 Sep 2009 09:43 PM |
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Sounds like a very undersized loop. Depending on the subsurface geology you should be looking at between 150-200' of borehole per ton for a water source closed loop in New Jersey.
-Adam
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Bergy
Basic Member
Posts:277
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| 25 Sep 2009 10:48 PM |
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Posted By njbillt on 09/25/2009 8:55 PM
It's a closed loop, 4/5? ton Carrier Infinty, 2 zone (one up, one down) 1700 sq ft home in New Jersey. The system has 2, 150 foot wells. His electric bill for August was $711. The contractor that installed it tried to sell me on one last summer and his heat bills last winter weren't great either. I'm glad I didn't jump. Clearly this thing is never going to pay off. I understand the theory behind geo, I just don't buy into it. The contractor told me it stores heat in the ground during the summer to be used in the winter, but in the next breath he tells me the ground recharges daily. My theory about my neighbors system is, the wells are insufficient and the heat pump is working really hard to extract heat, or in the case of summer has no place to dump heat. What say you experts? If indeed geo stores heat for the next season, is it not true that the efficiency of the thing diminishes as the seasons wears on and the capacity of the wells run out? Isn't it a little like trying to heat with an air source heat pump during the winter when the temps drop below 25, when your geo system has been extracting heat for 2 weeks and the ground is frozen solid?
Bill The "general" rule of thumb is one well/ton at 150'-200' deep. However, "general" rules should NEVER be applied without the calculations to back them up! Even though we do not have the required information to find the heat of rejection, it is VERY obvious this system is very short of pipe in the ground. Your friend needs to hire a QUALIFIED Geo contractor to access his problem and offer solutions. Geothermal operation is not THEORY, it is FACT! For example... A GeoComfort GT048 has a heat of extraction of 31,400 Btu's and a total heat capacity of 44,400 Btu's with an EWT (entering water temp) of 30*. A GeoComfort GT060 has a heat of extraction of 36,000 Btu's and a total heat capacity of 50,800 Btu's with an EWT (entering water temp) of 30*.
That's 31,400 Btu's of FREE heat for the 4 ton unit and 36,000 Btu's of FREE heat for the 5 ton unit. As the heating, or cooling, season wears on the capacity does diminish, but not as much as you think. The GeoComfort GT060 has a heat of extraction of 50,800 Btu's and a total heat capacity of 66,500 Btu's with an EWT of 50*. A properly designed AND installed loop field is KEY to the heat pump's ability to function as promised. Bergy
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heatoftheearth
Basic Member
Posts:113
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| 25 Sep 2009 11:23 PM |
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whats wrong with my neighbors system? He is short looped |
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njbillt
New Member
Posts:14
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| 26 Sep 2009 06:59 AM |
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Thank you all for the replies. It sounds like you all agree that the wells or "loops" are not sufficient. Adam refers to a "water sourced loop" and "subsurface geology", and Bergy talks about "entering water temperature". How do we know what's going on down there? What if it's just rock? How do we know there's water entering to recharge the therms? Is it possible the loops are too close together? Thanks again for any replies. |
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conniepangan
Basic Member
Posts:112
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| 26 Sep 2009 08:19 AM |
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Sorry to hear about your neigbhors nightmare. It's always said here in the forum that the key of geothermal success is installation. I am from North Jersey too where our geothermal took a full operation last November. It was a 3 Ton split system with 450' vertical loop with about 1700 SF. The first bill was quite high and then they adjusted our thermostat. Did his installer do some maintenance check on his system? Our installer sent electrician to rewire this summer. Although our summer this year hasn't experience heat wave, we still had days where we needed the cooling to kick in. Oh boy! I was very pleased with the result. Our August bill on electric was $45 and September was $50. Even our gas went down with the fact our desuperheater kicked in.
It shouldn't discourage you to think about your geo installation plan. Get bids, interview, manual j, reputable installers etc. |
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Bergy
Basic Member
Posts:277
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| 26 Sep 2009 08:50 AM |
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I'm amazed the system is running at all. If it truly is as short looped as it appears, I would think the unit would be shutting down on high limit while cooling and shutting down on freeze protect while heating.
Please refer to my first post about "general" rules... Generally speaking, with a properly designed vertical loop field I would not expect to see EWT above 85* in the summer, or lower than 30* in the winter. Differing types of soil, or rock, accept and give up their heat at different rates. The loop field MUST be designed for YOUR soil AND your Btu requirements.
Bergy
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joe.ami
Veteran Member
Posts:4377
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| 26 Sep 2009 09:26 AM |
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Posted By njbillt on 09/25/2009 8:55 PM
It's a closed loop, 4/5? ton Carrier Infinty, 2 zone (one up, one down) 1700 sq ft home in New Jersey. The system has 2, 150 foot wells. His electric bill for August was $711. The contractor that installed it tried to sell me on one last summer and his heat bills last winter weren't great either. I'm glad I didn't jump. Clearly this thing is never going to pay off. I understand the theory behind geo, I just don't buy into it. Bill You are not sure about system size, is it possible you are inaccurate about loops as well? Is this open or closed loop (some open loop systems have a supply and return well)? Loop depth and system tonnage (as well as surrounding soil) are factors that impact loop count. A 4-5 ton system is not a likely fit for a 1700SF home. Nor would the ductwork in this home likely support a 5 ton. If it is a 2 story 1700SF home with good insulation it might call for a 2 ton unit making our problems more likely elsewhere than number of loops (possibly grout or flush etc). I don't know if you are not well informed with the neighbors situation or spinning a yarn. The smugness of your tone suggests the latter ("don't buy into it"). If you truly wish to help your neighbor we'll need accurate information. Good Luck, Joe |
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Joe Hardin
www.amicontracting.com
We Dig Comfort!
www.doityourselfgeothermal.com
Dig Your Own Comfort! |
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njbillt
New Member
Posts:14
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| 26 Sep 2009 11:50 AM |
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I am going to get more accurate info about the tonnage for you. I am certain about the wells because I was in talks with his contractor last summer when they were drilling them. My house is over 4000 sq ft and he wanted to do 3, 150 foot wells for me. I may be confusing the tonnage with the quote he gave me. I stated in my original post that it is a closed loop system. I know they grouted the borings. My brother in law has an open loop, and I understand the difference. My neighbor himself doesn't know how many tons it is. I will try to get in his basement and see the model number and maybe that will tell us.
Thank, Bill |
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joe.ami
Veteran Member
Posts:4377
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| 26 Sep 2009 02:37 PM |
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Model # is a good starting point. See also if manual j load or operating cost calcs were provided.
J |
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Joe Hardin
www.amicontracting.com
We Dig Comfort!
www.doityourselfgeothermal.com
Dig Your Own Comfort! |
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joe.ami
Veteran Member
Posts:4377
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| 26 Sep 2009 02:42 PM |
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Hey Bill, what's the nearest major city?
J |
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Joe Hardin
www.amicontracting.com
We Dig Comfort!
www.doityourselfgeothermal.com
Dig Your Own Comfort! |
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joe.ami
Veteran Member
Posts:4377
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| 27 Sep 2009 10:00 PM |
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I won't be suprised if this is a 2 ton.
j |
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Joe Hardin
www.amicontracting.com
We Dig Comfort!
www.doityourselfgeothermal.com
Dig Your Own Comfort! |
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njbillt
New Member
Posts:14
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| 28 Sep 2009 05:09 AM |
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I appreciate all the input. My neighbor was away for the weekend. I'll update when I have more info. |
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joe.ami
Veteran Member
Posts:4377
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| 28 Sep 2009 05:32 AM |
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How 'bout nearest major city?
j |
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Joe Hardin
www.amicontracting.com
We Dig Comfort!
www.doityourselfgeothermal.com
Dig Your Own Comfort! |
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njbillt
New Member
Posts:14
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| 28 Sep 2009 05:38 AM |
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I was avoiding that to not disparage the installer. Philadelphia would be the nearest major city, but I don't know if that helps since we are on the other side of the river, a lot changes. The house is in Burlington County, NJ. |
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joe.ami
Veteran Member
Posts:4377
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| 28 Sep 2009 05:48 AM |
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Not trying to pick on the installer, just trying to verify the system size.
I don't see mention of the type of house....1700sf ranch or maybe a 1700sf cape cod (WITH ~1000 SF basement)....
j |
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Joe Hardin
www.amicontracting.com
We Dig Comfort!
www.doityourselfgeothermal.com
Dig Your Own Comfort! |
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joe.ami
Veteran Member
Posts:4377
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| 28 Sep 2009 05:56 AM |
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Also are there high cielings and ho well is it insulated? What do you pay/kwh
j |
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Joe Hardin
www.amicontracting.com
We Dig Comfort!
www.doityourselfgeothermal.com
Dig Your Own Comfort! |
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njbillt
New Member
Posts:14
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| 28 Sep 2009 07:16 AM |
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Posted By joe.ami on 09/28/2009 5:48 AM
Not trying to pick on the installer, just trying to verify the system size.
I don't see mention of the type of house....1700sf ranch or maybe a 1700sf cape cod (WITH ~1000 SF basement)....
j
It's a 2 story colonial with a partially finished basement. I would say it has good windows, average air infiltration and insulation. I have encouraged the owner to add attic insulation, and a radiant barrier, something I have done and feel made a huge difference in my home, especially the radiant barrier. The only geo system I have to compare to is my brother inlaws open loop system, and his bills are about half what my neighbor paid for August for a house easily twice the size of my neighbors. Isn't there some way to check a system? Comparing loop in and out temps?
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joe.ami
Veteran Member
Posts:4377
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| 28 Sep 2009 07:47 AM |
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Yes there are ways to check a systems performance. I'm still at square 1. It sounds like this house would require a 2-3ton, so I'm not prepared to condemn the loops yet.
Get us that model# and man j if you can or the op cost projection if available. I'm thinking that a 2 ton may cover more than 92% of the load.
RE operating cost, we need to know price per KW hour. Throwing out your brothers numbers tells us nothing unless we have more data as well.
I agree with you that something sounds amiss (with our electric rates for house described I would expect the annual op cost to be <$1,000). Also need to know if electric bills you mentioned cover just geo or whole house.
j |
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Joe Hardin
www.amicontracting.com
We Dig Comfort!
www.doityourselfgeothermal.com
Dig Your Own Comfort! |
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Bergy
Basic Member
Posts:277
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| 28 Sep 2009 07:50 AM |
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Your willingness to help your neighbor is admirable. However, I think the guys on this forum could help more if we were to speak with the owner. He/She will know more of the small details when asked questions and nothing will be lost in translation.
Bergy
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