This is a great forum with so many helpful people.

So, I have decided to go with closed loop because I don't want to deal with potential heat exchanger/well issues. Yes, I have read that the return wells can become stopped up by the same deposits that can collect in the heat exchanger.

So, I'm thinking closed loop with the addition of a water well. I'm hoping I can get the water well at a bargain if I have them all done at the same time.

So, I have the first driller come out today. His solution was three wells at 400 feet each. His verbal quote was $14K for the wells and manifold work. I was really hoping to keep the well cost under $10K. I have a second driller coming out tomorrow. I already have an estimate of $11.1K from him. I'm hoping he will lower that tomorrow.

I have some guys on my solar panel forum that are telling me that a Ground Loop Heat Pump in my area will never pay off. Not what I wanted to hear since I'm pretty serious about it. I think I mentioned that I'm in the Dallas area. Do any of you have experience with WSHP in this area? How should I go about calculating the savings over the 12 Seer system I'm currently running?

And no, I have never had a door blower test done. But I have to admit, it sounds like a good idea.

Posted By jonr on 16 Sep 2013 03:56 PM
Or just read the manufacturer charts.

The manufacturer charts don't tell you how to estimate the average EWT
or predict worst-case EWT temperature swings versus load, season, etc.
They also omit pesky little details such as soil conductivity & diffusivity.

Ditto for ASHP sizing info such as ambient averages and seasonal variation.

Experience: that which you possess immediately after you needed it.

The manufacturer charts don't tell you how to estimate the average EWT
or predict worst-case EWT temperature swings versus load, season, etc.
They also omit pesky little details such as soil conductivity & diffusivity.

At the time, the OP was asking about open loop.

Yep, I was considering whether to go with open loop or closed loop. I have decided I don't want to deal with the potential head ache's that can come from open loop.

Posted By jonr on 18 Sep 2013 06:05 PM
At the time, the OP was asking about open loop.

1) A geo-experienced pro would help him with that choice.

2) Can't compare GSHP to ASHP without good estimates of each.

3) That requires expertise in BOTH -- not just manufacturers spec sheets.


Experience: that which you possess immediately after you needed it

Your payback horizon is going to be a long one for a geo heat pump in the Dallas area. That doesn't mean it's not there, but you need some good expert advice to see if it works to your goals. I think the advice of a local PV solar installer is a good idea as well to ensure you get the best bang for your buck.
Blower door test first.

I live near you, in Plano; 3400 sf residence, single story, constructed 1992, with lots of glass, and nothing special WRT to insulation, windows, doors or roof.

In 2007 I replaced a 5 ton 2-speed Lennox A/C and a 140 KBTU NG furnace with a geo system using a closed loop, designed for 8 tons of cooling (5 + 3 ton 2-stage variable speed WaterFurnace Envision units connected to 8 vertical boreholes 300' deep each with 1" HDPE pipe).

At the moment I average $50/mo on a rolling 12 month basis, for all heating and cooling, using the geo system.  I did not keep the NG furnace.  Also, winter time closed loop water temp is warm enough here in the Dallas area such that you don't need to even consider aux heating coils for the geo units.

In my location I'm not on a natural stream, and thus my two choices were closed loop (more expensive installation cost, slightly not as good geo performance) or drill a deep well.  I chose closed loop because I wanted  lowest cost maintenance - avoiding efforts related to corrosion of heat exchanger due to open loop water salt and mineral content, related to fouling of heat exchanger and pumps due to debris, and related to well maintenance (occasional pump repair/replacement, well structure maintenance, and fouling of the intake).  I also wanted the insurance of maximally avoiding outage day(s) afforded by a closed loop.

Since in TX the cost of electricity is not exorbitantly higher than NG (10¢ vs 4¢ on an equivalent kWh basis), since our geographical location is so much a cooling driven climate meaning we don't need a lot of heating, and since the geo units are so efficient when EWT is in the 60s, I chose to avoid the added installation and maintenance expenses of keeping a NG fired furnace.

The best geo expert in the area, residential and commercial, is Eldon Hampton, owner of Geothermal Distribution, out of Rockwall.  I recommend you call them.  Phone number is 972-679-1438.  Geothermal Distribution is turn key - they handle the drilling too.

The best driller in the area is Johnson Drilling (used by Geothermal Distribution and many others).  Call Mark Johnson at 972-924-3411 .

Lastly, if you want to see a lot of information, real time and historical, on my geothermal system noted above, it's available on line at WEL0043 .

Also, my residence is annually featured on the DFW Solar Tour, coming up on Oct. 5th.  See dfwsolartour for tour information (it's free).  See tour-locations to determine if there will be any site locations near you that have geothermal.  See my-location for tour details for my residence.  You're welcome to come visit on the day of the tour.

Hope all of this helps.

Best regards,

Bill

Posted By joe.ami on 19 Sep 2013 10:11 AM
Your payback horizon is going to be a long one for a geo heat pump in the Dallas area.

Joe, you're not serious, are you?

I think you're one of the top few contributors here, and everyone reading and participating here is well advised to pay attention to what you have to say.

But once in a while, on two specific subjects (merits of air distribution zoning, economic benefit of geo in the South), you venture out into 'left field.'

Let's be realistic on economic benefit of geo.  Generally, if a customer is not purchasing a new residence with the opportunity to specify geo, or has existing HVAC equipment that's not at its lifetime usage, then a 'pencil to the paper' analysis almost always will show a change to geo to have very long break even period associated with the installation cost.  You know as well as I do that the optimum time to implement geo is at initial structure construction, or, at the time where the existing HVAC equipment has reached it's lifetime usage and thus it then becomes a 'sunk cost.'

That's not to say their aren't exceptions.  A structure using oil, for example, is always a candidate for doing the economic analysis.

Implementation of geo, done at the right time, and with reasonable assumptions, and using an expert installer, is a 'no brainer,' especially here in the South where there's no need for refrigerant-to-air heat exchange in cold temperatures (and thus avoiding the need for installation and running of aux coils), and where avoiding refrigerant-to-air exchange in high temps produces dramatic efficiency results.

Certainly, there are exceptions.  A difficult to implement loop field, exorbitantly high available electric rates mixed in with the subject of NG availability, and/or a location where well qualified installers are not available are some of them.

Overall, I'll respectfully disagree with your blanket statement that payback horizon is long for geo in the South.  Responding in kind with a blanket statement, implementing geo in the South is a 'no brainer.'

Best regards,

Bill

Hey Bill, thank you for responding to my thread. A friend (Chris) on the Solar Panel forum shared the link to your system yesterday. I'm so impressed. I have got to get me one of those monitoring systems. I installed Solar earlier this year and still check Enlighten every day. I have however finally stop going up on the roof every day to dust off my panels. :p

Interestingly, I had Mark Johnson out yesterday and another driller you may have heard of to day. His name is Frank Klufa. I liked them both, but so far, Frank has given me the best bid. I desperately want a water well for irrigation, but have settled on closed loop for the exact reasons you mentioned.

So Bill, have you been able to see any heat island effect as you continue to pump heat into the ground year after year. I spoke to the driller today about that. He said he thought the temperature buildup was mainly a problem when inadequate length ground loops were used. He went on to say that 300 feet per ton is usually long enough to allow the heat to dissipate.

So would you still recommend WaterFurnace? Have you had any issues with either of your Heat Pumps? Are your systems split, or self contained. I'm thinking of going with a split system because I think it will be an easier install in my existing house.

Posted By t5800512 on 13 Sep 2013 10:42 AM
 
... Wow, so this thing eats paragraphs?

If you use IE, you have to turn on 'Compatibility View.'  Then, everything works fine.

I'm using IE10.

(More later this AM.)

Best regards,

Bill

Met with a third driller this morning. He quoted me $10K to $12K for the four 300 foot wells and manifold. But he told me $12K on top of that to add a water well. Really? What to heck! Anyway, I'm waiting for him to give me some firm pricing.

Why four tons? Do you have a professional load analysis, or are you
"winging it" based on the performance of your old conventional A/C?

Could save a lot of money if a three ton geo system would handle the
load -- maybe with some affordable improvements to the envelope.

...just sayin'

Looby

I have been quoted $40/ft for well drillin'...so, 4*300*$40 would be $48,000 w/o manifold. How about that for a quote?

Hi Looby
Yes, I chose 4 ton because a 12 SEER 4 ton ASHP is working good for me now. I could probably downsize a little, but I have a 600 foot room addition that I will eventually finish out. It would be nice if I could use my central air conditioner to partially heat and cool the room addition. I built the room addition with a 1 ton split system knowing that alone wound not be enough. I chose to leave this detail out of my initial thread because I did not want to put folks to sleep. You know how those long introductions can be.

NooBoo, where do you live? Is your house build on stone or something? Because that sounds like crazy talk.

I have a home in the cold and one in the desert.


The going rate in the cold climate area is $40/ft, through sedimentary rock and sand.


Must be the price of diesel.


Or, because it is relatively shallow, the mobi charges are factored in.

About your closed loop job, why the difference in price for a water well? The quote is 400% higher. Is casing that expensive?

Could an ungrouted 'closed' loop go down the same hole as a cased water well? Pulling a pump might present a problem with that type of setup. What do you think?

I have thought about that same thing. But I'm afraid that would compromise the heat transfer ability of the closed loop. Kind of like putting the closed loop down a hole that does not get grouted.

Part of the problem with planning a GSHP open loop well is knowing the quality of the water that will be found. So, if I'm going to have to pay full price for a water well, maybe I should put it in first and then evaluate the water to see if it would be suitable for an open loop well. If it won't work for GSHP, I would at least have my water well. If it is good, drill a second well for the return water.

My boreholes are 300 feet, one for each ton of capacity, 8 total.  Each are spaced at least 20 feet away from any other borehole.

I have been monitoring for the possibility of borehole field heating.  So far, the data is inconclusive.  Below is a picture.

The first full year of data availability ('09), avg annual EWT was 71 degrees.  For 2010 EWT increased to 71.8 degrees, for 2011 EWT further increased to 73.0 degrees, and average temp last year was 73.1 degrees.

This might suggest indeed a borehole field heating affect, but, avg outside temp has increased every year too.  In '09 it was 66.7 degrees, in '10 it was 67.4 degree, in '11 it was 68.7, and for '12 it was 69.5 degrees.

I'll continue to monitor this.



Best regards,

Bill

Hey Bill,
I spent some time today talking to Eldon. You are right, he really knows his stuff. It sounds like he may be able drill my wells for the price I had in mind. I have been planning on putting in the Bryant split GSHP because I can purchase it wholesale. But Eldon about has me convinced to go with the WaterFurnace 7 series. I'm hoping to hear back from him soon. I'm interested to see how much more the WaterFurnace will cost me.

Does anyone know who build the Carrier/Bryant system? I'm wondering if it is ClimateMaster.