docjenser: I hear you on both the quality of the design and qualifications of those who did the measurement, but it's the study YOU pointed to- should I assume it's YOU doing some cherry-picking, only putting up bottom of the barrel designs for discussion? ;-)

But seriously, I don't know how all third party testers manage to randomly select bottom-of-barrel designs if that doesn't in some way represent the industry average. The more publications there are out there like that, the narrower the 1-sigma error bars become. Until I see something different I'm not going to assume the industry average is dramatically better. Just because a good designer COULD do better means squat, if every time somebody throws a dart at the sample it lands on crap. We need more numbers to find the true 1-sigma limits, but every documented independently measured US installation I've found online comes up in the 3s, sometimes the low 3s, sometimes the high 3s, but I've still not seen 4. And most of these appear to be put up as examples of just how green these houses & systems are, yet it's easy to find fault with both the building envelope and the mechanical designs with only a small amount of analysis.

And that guy in VA who dropped $40K+ on 6 tons of geo should ask for his money back if they won't or can't fix the design errors and get his performance at least above 3.5. At VA winter temps & dew points a ductless would hit his 3.3-3.4 average pretty easily.

Dana, thanks. Best regards, Bill

Posted By a0128958 on 24 May 2012 04:09 PM
Dana, thanks. Best regards, Bill

Yer welcome!

Does this mean you're going to pull up stakes & come north to bring the local price average for GSHP down to something under $8K/ton, and get rich in the process?   (Bring some winter clothes if you do.)

Nope! If you do it right, there's plenty of opportunity here! It's really no different than anywhere else - to get geo working right requires a lot of water loop expertise and geology knowledge.

It's just a different set of challenges down here. Imagine, for example, having to worry about wearing out your borehole field! I've got a friend down the street, whose EWT now goes North of 105 degrees every Summer. Each year EWT has gotten a little higher, as the Earth has not ever had enough time to absorb all of the heat being put into it. Course of time is about 15 years.

Best regards,

Bill

105F ... Each year EWT has gotten a little higher,

That's when you wish you had some groundwater flow to carry that heat off to your neighbor :-)

In a cooling-dominated climate an EWT anywhere near or above ambient air temperatures begs the question of why spend $15k on a complicated system of bores, pipe and pumps when the $200 fan motor and blade on a conventional ASHP gets to reject heat into same or cooler heat sink?

I suspect that for geo to be successful in cooling dominated climate EWT must be consistently 5-10*F below design outdoor air temperature. Otherwise EER and COP fall to the point that conventional split or minisplit ASHP make more sense.

An obvious exception (that buys some of my steak and beer) is beachfront homes whose blown sand and salt air dramatically shorten life of ASHP outdoor units.

Posted By engineer on 24 May 2012 11:35 PM
In a cooling-dominated climate an EWT anywhere near or above ambient air temperatures begs the question of why spend $15k on a complicated system of bores, pipe and pumps when the $200 fan motor and blade on a conventional ASHP gets to reject heat into same or cooler heat sink?

I suspect that for geo to be successful in cooling dominated climate EWT must be consistently 5-10*F below design outdoor air temperature. Otherwise EER and COP fall to the point that conventional split or minisplit ASHP make more sense.

An obvious exception (that buys some of my steak and beer) is beachfront homes whose blown sand and salt air dramatically shorten life of ASHP outdoor units.

My friend gave up last year, and instead of 'refurbishing' his borehole field, he cut the pipes and had ASHPs put it.  With some of the boreholes within 10' of each other, with the prospect of re-drilling these, at $1K each for 300' depth, and with the strong probabiliy of adding more boreholes, again at $1K each, along with reconnecting up the loop pipe, the cost was just too much compared to simply saying 'goodbye' to the borehole field and putting in ASHP units.

The heat here is an absolute killer.  And, the ASHP guys easily can come in, in one afternoon, and have you all fixed up.  Actually, the 'Christmas season' has already started for the ASHP guys.

I feel lucky.  My EWT doesn't yet get above 85°, no matter how hot it gets.  But I'm watching it over the next few years.

I don't know what design outdoor air temperature is for Dallas.  I do know record temperature is about 112° F. 

P.S., my visitors last year for the home energy tour asked why my grass was still green in my front yard, where I have 8 wells with a total of about 1 mile of pipe.

Best regards,

Bill

Posted By a0128958 on 25 May 2012 12:27 AM

Posted By engineer on 24 May 2012 11:35 PM
In a cooling-dominated climate an EWT anywhere near or above ambient air temperatures begs the question of why spend $15k on a complicated system of bores, pipe and pumps when the $200 fan motor and blade on a conventional ASHP gets to reject heat into same or cooler heat sink?

I suspect that for geo to be successful in cooling dominated climate EWT must be consistently 5-10*F below design outdoor air temperature. Otherwise EER and COP fall to the point that conventional split or minisplit ASHP make more sense.

An obvious exception (that buys some of my steak and beer) is beachfront homes whose blown sand and salt air dramatically shorten life of ASHP outdoor units.

My friend gave up last year, and instead of 'refurbishing' his borehole field, he cut the pipes and had ASHPs put it.  With some of the boreholes within 10' of each other, with the prospect of re-drilling these, at $1K each for 300' depth, and with the strong probabiliy of adding more boreholes, again at $1K each, along with reconnecting up the loop pipe, the cost was just too much compared to simply saying 'goodbye' to the borehole field and putting in ASHP units.

The heat here is an absolute killer.  And, the ASHP guys easily can come in, in one afternoon, and have you all fixed up.  Actually, the 'Christmas season' has already started for the ASHP guys.

I feel lucky.  My EWT doesn't yet get above 85°, no matter how hot it gets.  But I'm watching it over the next few years.

I don't know what design outdoor air temperature is for Dallas.  I do know record temperature is about 112° F. 

P.S., my visitors last year for the home energy tour asked why my grass was still green in my front yard, where I have 8 wells with a total of about 1 mile of pipe.

Best regards,

Bill

$1000/hole!!!!! The going retail rate up here is $2500-3000. I don't know how you make a living at that rate. Anyway, the ambient temp argument is one of the the reasons I concentrate on ASHPs and i think that is the future.

Posted By a0128958 on 25 May 2012 12:27 AM

Posted By engineer on 24 May 2012 11:35 PM
In a cooling-dominated climate an EWT anywhere near or above ambient air temperatures begs the question of why spend $15k on a complicated system of bores, pipe and pumps when the $200 fan motor and blade on a conventional ASHP gets to reject heat into same or cooler heat sink?

I suspect that for geo to be successful in cooling dominated climate EWT must be consistently 5-10*F below design outdoor air temperature. Otherwise EER and COP fall to the point that conventional split or minisplit ASHP make more sense.

An obvious exception (that buys some of my steak and beer) is beachfront homes whose blown sand and salt air dramatically shorten life of ASHP outdoor units.

My friend gave up last year, and instead of 'refurbishing' his borehole field, he cut the pipes and had ASHPs put it.  With some of the boreholes within 10' of each other, with the prospect of re-drilling these, at $1K each for 300' depth, and with the strong probabiliy of adding more boreholes, again at $1K each, along with reconnecting up the loop pipe, the cost was just too much compared to simply saying 'goodbye' to the borehole field and putting in ASHP units.

The heat here is an absolute killer.  And, the ASHP guys easily can come in, in one afternoon, and have you all fixed up.  Actually, the 'Christmas season' has already started for the ASHP guys.

I feel lucky.  My EWT doesn't yet get above 85°, no matter how hot it gets.  But I'm watching it over the next few years.

I don't know what design outdoor air temperature is for Dallas.  I do know record temperature is about 112° F. 

P.S., my visitors last year for the home energy tour asked why my grass was still green in my front yard, where I have 8 wells with a total of about 1 mile of pipe.

Best regards,

Bill

 The 1% number for Dallas is 98F, so I think you have a ways to go before it underperforms conventional 1 & 2 stage ducted air source AC.

Just for your yardstick reference. East Pa area. I had 4 bids for geo for my house 2 years ago. Replace existing 4T ASHP with 2 stage 4T geo W-A, borefield, DSH, use existing ducts. Bids came in from 22 - 30K. I ended up at $23K with 3x260' bores. EWT stays above 40F all winter.

So thats $5.75K/Ton.

System is fantastic so far. House is more comfortable and electric use is waaayyyy down. We run it more that ASHP, since its so economical to run . I calc'ed payback at 8 years vs high end ASHP after rebates at our electric rates.

Never considered mini's. Not really suitalbe for our 2 story colonial. No central circ, filter, or humidification in winter. Existing ducts already there. etc...

Chris

Posted By Dana1 on 25 May 2012 12:33 PM
l
 The 1% number for Dallas is 98F, so I think you have a ways to go before it underperforms conventional 1 & 2 stage ducted air source AC.

Dana, thank!  Best regards,  Bill

At some point, the quest for higher COP is better achieved with air source to hydronic storage running at night (when it is ~20F cooler). 10 foot borehole spacing wasn't a good idea.

Chris- Clearly that would be a super-bargain, in my neighborhood! (Even your high-bid of $30K for 4-tons would beat the local average here by about five grand, but it's likely that SOME 4T system here would hit that number.)

You probably took the 30% tax credit, bringing the out-of-pocket to about $16K before other state & local subsidies? What was the final post-subsidy cost?

Dana......to get the price down to 6K/ton up there.....get ride of the unions     :)

Fantastic C:  !!!
In Harrisburg PA
with a 5-ton dual compressor [3-staging, 18MBtu first] w/ 100% Domestic-HW (in cooling mode 100%, loop pumps shut off) - - - $Top of the line$- I think you will find a very happy psychologist, who sends me Harry and David's fruit each year, spent less than that $5.7/'ton';and with a new duct system (less labor, he put in ducts) [eh? compares to mini's?] !
That is in part w/ 3x240' bores and (not always recommended, oly twice installed since 1983 !) all in/on ONE single 1.25 line x ~ 1,600ft, saved more installed costs @ no headers nor labor-intensive building etc., comparatively. His driller even horizontally drilled, 'moled' 12+ feet into basement wall, saving other costs. Loop stays above 35, and the 5-(real compressors inside unit) tons are like "Size 5.8-6.0's" in among other brands 'ratings', and that would put it even far less than even $5.2k/t.

His in-floor radiant slab-walkout- 1/2-finished-basement +all 2 top floors, has- alone- over a 30-yr ROI, compared to since he can comfortably heat, very inexpensively, with just using the (better-directed) forced-air. Air in this GT- is always at- 3 or 4F above any 'tepid' misconcerns. The system has 96F-97F air temp set with modulating blower speed controlled by a changeable program set point (living 67-deg, is made more comfortable). Claims all utilities in  about 3200 living w/ 1200 basement only insulated from 2ft below grade to exposed walls R-6, to R-7, but foiled-foam boards: @ $ 93.-$95 per mo, budget, family of 2. His prog.set.back.thermostat is used a lot  b/c of w/ an oversized and staging GT (Strip KW supplement is turned off for the past 4 years to  -5F's). That same size/type GT System is heating 4400 sq ft to a  -10F below, different insulation over 1800 basement sq ft. w/ not using supplemental KW strips, and loop gets closer to 34F since 2005.

Thanks Chris !

"1000 bucks/ 300'  "  COME TO PA NOW !!!!!

Dana all $ before credits/rebates.

Curt:
Seems 77-deg entering is all I find on GEOCOMFORT  www.Enertechgeo.com  -data, as was for COOLING (absorbed overall) ratings like was since the 1980's.  Loops over 88deg. EF/EW/EL better get near 4gpm per compressor-labled ton (12MBtu's) in any GT/Chiller box, or rack, - for any "high" efficiency. Now the pressure-drops and pumping horsepower of less than 17 tons or so per 1hp pumps (calc) will put all GT-er's in D1's range of mathematical arguement(s). - Not quarrelling, just the postulates to in-situ results to answer his valid arguements.  Dana: The head/suction - pressure/temps gauge readings, per install, tell your story, as you well know

Posted By robinnc on 25 May 2012 10:14 PM
Dana......to get the price down to 6K/ton up there.....get ride of the unions     :)

sshhhh youz !  they keep me busy gettin' mo' work! Profitablility for Performance Contracting prevails/ and gets me their rate of wages and more.

Posted By Dana1 on 25 May 2012 04:28 PM
Chris- Clearly that would be a super-bargain, in my neighborhood! (Even your high-bid of $30K for 4-tons would beat the local average here by about five grand, but it's likely that SOME 4T system here would hit that number.)

You probably took the 30% tax credit, bringing the out-of-pocket to about $16K before other state & local subsidies? What was the final post-subsidy cost?

Dana-  We did use the 30% Fed credit and also $900 or so local utility rebate.  I payed another $800 for yard repairs. It was a mucky mess inside the hay bales.  Net cost around $16K.  We have red clay and shale here.  Driller had no issues except lots of water starting at 60 ft.  We used thermal grout and clip spacers on 1" HDPE. 

Not sure what your soil type is and if that ups costs in your area.

System in super comfortable for us.  Love the dehum low fan speed on super humid spells like now.

I added a relay off Y2 to the second loop pump, so we only use (1) 26-99 for most of the time to save on pumping power.  We leave the resistance breakers off all the time.  could have gone with 3 or 3.5 ton, but Man. J said 4T....

Higher end ASHP was in $9-10K range.  Late night winter output was considerably lower if we went with ASHP.  I was toying with upping to 5T ASHP to limit resistance, but swayed to GEO.  Ducts would be pushed a bit in that route.

Maybe some Pa guys can make some money in your area??

Chris

"We leave the resistance breakers off all the time. could have gone with 3 or 3.5 ton, but Man. J said 4T...."

To be clear, manual J didn't say 4T, the system designer did. That you never employ auxiliary would suggest you are significantly oversized if you are in a northern climate and therefore could have purchased a smaller unit for thousands less.
That said, larger unit may be much less expensive to operate (justifying extra install expense) depending on the cost kwh of electricity in a given AO.
In an area like mine where electricity is cheap, the larger unit occasionally costs more to operate.
We also tend to look at higher set points down the road if it is somebody's forever house. If they want 68* now, we might op cost compare 75* for waning years and blood thinners- in these cases folks may choose a slightly heavier design (that depends less on electric aux. at higher set points).
All designs are compromises, inst vs op cost, heating vs cooling driven etc. Many designs are okay when informed choices are made. Simply wanted to remind that aux is not always the antichrist it is made out to be.
j

"therefore could have purchased a smaller unit for thousands less"

How much of the "thousands less" would be just the packaged unit itself?

Reason I ask is my installer sold me a 5-ton unit, then reduced it to a 4-ton but never changed the invoice, my copy still says 5-ton.

The unit still has to have all the same components, just a lttle different size.

ChrisJ RI

"therefore could have purchased a smaller unit for thousands less"

How much of the "thousands less" would be just the packaged unit itself?

Reason I ask is my installer sold me a 5-ton unit, then reduced it to a 4-ton but never changed the invoice, my copy still says 5-ton.

The unit still has to have all the same components, just a lttle different size.

ChrisJ RI