Blackflag,
OP (original poster) distinguishes you from all following contributors and is not intended to slight. It also comes in handy when your name slips my feeble mind
That I am disgusted that an on line company would violate his dealership agreement with Climatemaster does not mean I'm disgusted with you for getting a deal on a good product. I offer the following caution: warranties are only available through Climatemaster to certified CM dealers. We also have ferreted out on- line geo sales scams before.
When I call you DIY (and again not an insult) you have chosen to be the general contractor. What you percieve as mark-up on the heat pump is a fee for design (system sizing), hiring and cordination of trades (plumber, electrician, driller/excavator), labor warranty and part warranty administration, perhaps permits and most importantly, ownership of the results....(what if it costs you much more to run than you expected?). Is this OK, sure as long as you understand what you aren't getting.
Regarding the size, I don't remember if you provided us with an actual heat loss or if I pulled up a comparable house, but yes I suspect 4 tons would be my pick for your home for a variety of reasons. That doesn't mean you'll be unhappy with 5, it is just slowing your ROI. It also requires a lot more duct (a TT64 needs 384 sq" of return air).
I truly wish you well,
J

Joe - I agree, "bashing" is a bit harsh. What you do is more subtle than that.

What I object to is undermining those who bring up other viable alternatives to Geo. Eric made perfectly reasonable assumptions to give ballpark calculations. They weren't best case nor were they worst case. I notice that he's replied with his own reasoned response, so I won't belabor that issue.
Perhaps my skin is a bit thin after our discussions of heat pump water heaters. As an independent energy and building science consultant, I make it my business to be as technology-neutral as possible - I'm looking for the best solution for each particular client. In some cases, that's geo, in others, it's a conventional heat pump, and in others, it might just be sticking with an old clunker. It all depends on the unique situations, which you appear to be in agreement with.

For specifics, even in your reply, you compare the circulator for a boiler with that of a close loop geo system. However, those don't cancel each other out. If you've got a hydronic geo system, you need both pumps, so the geo system will have a greater draw. If you're comparing a forced air geo with a hydronic system with a boiler, well, then we'd need more information for comparison.

Likewise, in many cases, closed loop performance is going to be substantially less than manufacturer's specs since the ground around the loop will usually only be 50F at the start of the heating season due to ground heat "suck". While you may do proper loop field design and implementation so that your EWT may only drop to 40F, the installers I've spoken with and, I believe, the IGSHPA, suggest spec'ing systems based on a more realistic, mid-season EWT of around 32F. Check your COP tables at 32F and you'll find a COP of 3.0. (ARI 330 spec). Add in loop pump and you're pulling the real system COP, excluding hydronic circulator or air handler, down below 3.0. I admit that my 1/2HP comment previously was an overestimate for closed loop, so the degredation isn't as high, most likely it's only knocking off about 0.2 COP. So your 3.0 estimate isn't really low-ball, it's probably fairly accurate.

The main thrust of my argument is that we have to be equally brutal in our analysis of all technologies. You're a lot better than most, and overall, I think your contributions here are positive.

>While slightly off topic from the op question, I take great offense at the statement " that the reason drillers charge more for grout is that they do not have the right equipment".

Eric- my comment was more about charging more for thermally enhanced grout vs. regular grout. Dewayne is able to charge the same for thermal as regular grout because sand is cheap and he already has a positive displacement piston pump capable of pumping it. Many of our water well drillers in PA don't have any grout pump and just use bentonite chips when needed for those few instances a seal is required. With mud rotary drilling in the coastal plain where seasoned drillers such as yourself are able to drill incredibly economically, putting in 20% more borehole can make perfect sense when compared to buying additional equipment and hauling sand when you already have a perfectly good mud pump on board.

Jonr- It looks like there is now at least one available software package able to do the finite difference conductive and convective heat transfer calcs made by SoilVision: (www.soilvision.com/newsarchive/PressRelease/Release2010-03-20.shtml) It does run about $10K though.

-Adam

Posted By joe.ami on 17 Apr 2010 09:45 AM
Blackflag,
OP (original poster) distinguishes you from all following contributors and is not intended to slight. It also comes in handy when your name slips my feeble mind

but yes I suspect 4 tons would be my pick for your home for a variety of reasons. That doesn't mean you'll be unhappy with 5, it is just slowing your ROI. It also requires a lot more duct (a TT64 needs 384 sq" of return air).

ok, duh - OP!

i am so confused now! half the people (here onf offline) say go 4 tons, the other half say 5 tons?! I was hoping for a consensus! (wink wink)

my basic understanding is:

4 tons: less electricity to operate and less up front cost (drilling and unit) - hence faster ROI - plus possible better dehumidification and slightly higher COP am i missing something?

5 tons: better protection against very cold snaps without use of backup, will run mostly on stage 1, if i decide to do addition etc, i will have enough capacity to condition the space (up to a point).


I have the ClimateMaster Tranquility 27 specs in front of me:

                                                                   BTU | EER                    BTU | COP
for 4 ton running 2 stages:       cooling:       50,600 | 17.9              Heating: 37,500 | 4.0

for 5 ton running 1 stage:         cooling:       49,800 | 25.3              Heating: 37,500 | 4.3


now i a total newb - but it looks to me IF the 5 ton is running on 1 stage, and assuming the 4 ton would be running on 2 (im i right or wrong here) - 5 ton is more efficient?

Posted By tinoue on 17 Apr 2010 10:14 AM

Likewise, in many cases, closed loop performance is going to be substantially less than manufacturer's specs since the ground around the loop will usually only be 50F at the start of the heating season due to ground heat "suck".

This is not necessarily true.

Look at the graph of my closed loop


You can clearly see that when I started heating at about the day 190 mark,  my EWT was about 67°.

Posted By blackflag on 17 Apr 2010 10:54 AM

4 tons: less electricity to operate and less up front cost (drilling and unit) ....

I believe loop design and sizing depends mainly on your heating and cooling loads
and NOT on the tonnage of the heat pump. During heating season, you'll be pulling
the same number of BTUs/week out of the ground regardless of whether you have
a 4-ton unit running 15/7 or a 5-ton running 12/7.

Similar logic for electricity consumption -- a 5 ton unit draws more kW, but it
should run for fewer hours/year.

...it looks to me IF the 5 ton is running on 1 stage, and assuming
the 4 ton would be running on 2 (im i right or wrong here)...

Mostly wrong, I believe. Either unit should be running in stage1 for the majority
of its annual operating hours, but the 5-ton unit would run for fewer hours.

Posted By blackflag on 17 Apr 2010 10:54 AM
now i a total newb - but it looks to me IF the 5 ton is running on 1 stage, and assuming the 4 ton would be running on 2 (im i right or wrong here) - 5 ton is more efficient?

the 4 ton will still be running in 1st stage the majority of the time at a COP= 4.6 . Your dealers should be giving you an estimated run time in stages 1 and 2. In a very broad, uncalculated, not applicable in every circumstance sense. Usually the smaller heat pump is more efficient and will last longer

Posted By tinoue on 17 Apr 2010 10:14 AM
Likewise, in many cases, closed loop performance is going to be substantially less than
manufacturer's specs since the ground around the loop will usually only be 50F at the
start of the heating season ....

I must respectfully disagree. The manufacturers' specs, (i.e., ARI 330 and ISO/ARI 13256-1),
are quite conservative. With either standard, closed loop COPs are specified at 32F EWT and
differ only in entering air temperature (70F and 68F, respectively).

Yes, overall system efficiency must also account for power consumption of pumps and
air handlers ...and that's where trained geo designers and engineers earn their keep.

Posted By Looby on 17 Apr 2010 12:32 PM

I believe loop design and sizing depends mainly on your heating and cooling loads
and NOT on the tonnage of the heat pump.

A smaller heat pump that relies on backup heat for some of the load will have a smaller loop since not all of the heat has to come from the loop.

Posted By geodean on 17 Apr 2010 01:11 PM
A smaller heat pump that relies on backup heat for some of the load will have a smaller loop since not all of the heat has to come from the loop.

True, but it's a complex relationship since EWT depends mainly on the design of the
loop and the total number of BTUs extracted "recently" -- independent of HP tonnage.

Regardless of tonnage, the smaller the loop the lower the EWT (for a given heating load),
and each 10F drop in EWT reduces a heat pump's BTU/hr capacity by 10%-15%. Thus, a
a 4-ton unit at 40F EWT can produce nearly as many BTU/h as a 5-ton unit at 30F EWT.

If the loop is too small for the load, more tonnage won't help much.

Posted By Looby on 17 Apr 2010 01:42 PM

If the loop is too small for the load, more tonnage won't help much.

i'm thinking of getting 2 400's veritcal for the 5 ton

Posted By heatoftheearth on 17 Apr 2010 12:52 PM

Posted By blackflag on 17 Apr 2010 10:54 AM
now i a total newb - but it looks to me IF the 5 ton is running on 1 stage, and assuming the 4 ton would be running on 2 (im i right or wrong here) - 5 ton is more efficient?

the 4 ton will still be running in 1st stage the majority of the time at a COP= 4.6 . Your dealers should be giving you an estimated run time in stages 1 and 2. In a very broad, uncalculated, not applicable in every circumstance sense. Usually the smaller heat pump is more efficient and will last longer

brochure says stage 1 80% of the time...

Posted By geodean on 17 Apr 2010 11:09 AM

Posted By tinoue on 17 Apr 2010 10:14 AM

Likewise, in many cases, closed loop performance is going to be substantially less than manufacturer's specs since the ground around the loop will usually only be 50F at the start of the heating season due to ground heat "suck".

This is not necessarily true.

Look at the graph of my closed loop


You can clearly see that when I started heating at about the day 190 mark,  my EWT was about 67°.

It's great to see some hard numbers. That WEL system is great for showing actual performance. It all goes back to each install being unique. It looks like you've got good performance - probably plenty of loop and a water table that is moving through the loop field. I'd like to see more people's graphs. In my experience here in SE PA, well drilling is so expensive that most installers are using less well depth than they should and ignoring local geology, resulting in generally inadequate ground thermal capacity for the system. As you pros know, a properly designed system will take all this into account and SHOULD be designed so that the ground temperatures don't drop too far through the heating season (or rise to high during the cooling season). The problem is, pros like those on this list are in the vast minority. Every HVAC contractor in the area is jumping on the GSHP bandwagon without really knowing what they're doing. Even most of the seasoned guys in my area design by rule of thumb and undersize loop fields in order to keep the systems affordable.

Posted By blackflag on 17 Apr 2010 10:54 AM
I have the ClimateMaster Tranquility 27 specs in front of me:

                                                                   BTU | EER                    BTU | COP
for 4 ton running 2 stages:       cooling:       50,600 | 17.9              Heating: 37,500 | 4.0

for 5 ton running 1 stage:         cooling:       49,800 | 25.3              Heating: 37,500 | 4.3


now i a total newb - but it looks to me IF the 5 ton is running on 1 stage, and assuming the 4 ton would be running on 2 (im i right or wrong here) - 5 ton is more efficient?

Please do not assume 1st stage is so much more efficient than 2nd stage as ISO/ARI 13256-1 numbers suggest. 1st stage gets a 9*F boost for EWT under test conditions. I wouldn't count on that in a real world application. Maybe one of the WEL guys can offer some numbers based in reality.

The type of soil is one of several factors for loop size.  An experienced well driller will know what under your grass.  Here in Maryland near Wash DC I had 5 colors of clay come up when my wells were put in last summer.  50 miles south in So. MD you get more sand and shells.

Around here its 180 feet per ton.  I went 4 200' for my 3 ton WF. 

My install pics

CH

Posted By tinoue on 17 Apr 2010 01:49 PM



  probably plenty of loop and a water table that is moving through the loop field. I'd like to see more people's graphs.

Actually my loop is in hard dry clay with no water table  at all.

Posted By geodean on 17 Apr 2010 08:11 PM

Posted By tinoue on 17 Apr 2010 01:49 PM
  probably plenty of loop and a water table that is moving through the loop field. I'd like to see more people's graphs.

Actually my loop is in hard dry clay with no water table  at all.

Interesting. I ran some numbers based on your graphs and other data. Your house is very efficient indeed. Based on the numbers, you home only needs about 2.25 BTUs/HDD/SF, making it more efficient than any free-standing home I've measured. Even more interesting is that, based on the total heat delivered to your home on a 15F day, the heat load for your place is only 16kBTU/hr - incredible!

Of course, based on those numbers, your system is only running a maximum duty cycle of about 33%, so it's no wonder your ground temperatures barely waver.

I may have misinterpreted your graphs however, but it sure seems like those numbers are in the right ballpark.

Posted By geodean on 17 Apr 2010 08:11 PM
Actually my loop is in hard dry clay with no water table  at all.

Some loop! That's 1/4 mile per ton, correct?

Posted By tinoue on 17 Apr 2010 10:20 PM
...the heat load for your place is only 16kBTU/hr - incredible!

Possibly due to incredible solar gain?

http://maps.google.com/maps?q=40.542990,+-112.0263008&t=k&z=15