Pulled the trigger! Wall of fame or wall of shame?

[thenuke]

Howdy!

I just gave the official "yes" to a geothermal proposal I've been mulling over for about 30 days now.

I just thought I would share the details of the proposal (minus price of course) with everyone to make sure I can post the results of the install on the wall of fame and NOT on the wall of shame.

Location: Outside Green Bay, WI
Home size: 4913sq ft TOTAL - 1st - 2028sqft 2nd - 857sqft Basement - Unfinished, will finish later!
Orientation: Facing North, most windows on South side
Insulation: 2x6 with R-23 BIBS, R-50 attic, foam attic seals, foam box sills
Heat Load: 60,189Btuh
Cooling Load: 25,077Btuh
Electric Cost: $.12
Gas Cost: $1.25

Proposed System:
WaterFurnace Envision ND049 ECM
12 60' trenches @ 8ft depth w/ 500ft of slinky in each (6000 total feet)
Electric auxiliary internal duct heat 8kW
Envision ND dual capacity Series Water Unit
Electric with GeoAsist Water Heater
3 Zones
RenewAire ERV

Heat calc and job info attached for your destruction.
- Loop seems kind of fat, and WF unit seems kind of small, but I don't know jack, and all the math seems to work, let me know if I'm nuts.

[junkhound]

... a query to the moderators.. before violating any rules...

Permissible to copy and paste a pro forum description of shop built evaporators for GSHP (system COP=5.6) better than anything commercially available? .. here?

Posted it in the pro geo section as a manufacturing possibility for energetic and aggressive young guy going into the business, but 'so simple', that in open area probably would be considered DIY??

[thenuke]

I'm not sure I follow, but I'd love to see it. Otherwise if it can't go here, you can e-mail it to me. thenuke -at- gmail dot com

[crash11]

Well given the drastic difference between your heat gain and heat loss I guess they chose a good size unit. You should be pretty happy with that setup. My only concern is the loop design. I hope they don't plan to do 6 parallel loops. They are probably going overkill on how much pipe they are burying as well. All-in-all it looks good. My choice for your heat gain and heat loss would be a dual fuel setup with a little 2 ton geo unit and a gas furnace.

[thenuke]

Well given the drastic difference between your heat gain and heat loss I guess they chose a good size unit. You should be pretty happy with that setup. My only concern is the loop design. I hope they don't plan to do 6 parallel loops. They are probably going overkill on how much pipe they are burying as well. All-in-all it looks good. My choice for your heat gain and heat loss would be a dual fuel setup with a little 2 ton geo unit and a gas furnace.

Thanks. Not being an expert, what kind of loop design should I be looking for? And better too fat than too skinny, right?

[crash11]

Well, if they are burying that much pipe I'm sure they'll be using 3/4". Also, in a 4 ton system you want 12 gpm total flow (the industry likes to use a 3 gpm per ton guideline). According to my tables the best flowrate using 3/4" pipe is around 4 gpm. Too little and you are in the laminar flow region, and too much is just wasteful turbulence. So if you want a TOTAL flowrate of 12 gpm then that means you want 3 parallel loops (4 gpm for each loop = 12 total). That's what you want to look for is how many parallel loops they are running. Additionally, if they are professionals they will arrange their header in a reverse/return fashion. Lastly, I've been told by my unit's manufacturer (fhp) that you don't want too much total flow or too little. So make sure they verify you're getting 12 gpm exactly (+/- 0.5 gpm). I was told too much flow causes the unit to not work properly in heating season.

Edit: I did a little digging and found the pressure drop you should be looking for on your unit. The way they figure out system flowrate is by measuring the pressure difference between the two diagnostic ports on your pumping station. Anyway the pressure drop should be around 3.8-3.9 psi depending on the temperature of the water.

[weber]

Hmmmnnnn.....

Something souds a little off to me.

Your last page indicates the min and max loop temps.

Min looks good, max looks to low.

But it is a little hard to read.

[weber]

That is a good piece of equipment, dual capacity, variable speed.

What will they be using in the loop?

[weber]

And did you get the 55 year warranty on the loop?

[beenthere]

[QUOTE=junkhound;3061712
Posted it in the pro geo section as a manufacturing possibility for energetic and aggressive young guy going into the business, but 'so simple', that in open area probably would be considered DIY??[/QUOTE]

No.

That would be DIY instructions.

[thenuke]

Hmmmnnnn.....

Something souds a little off to me.

Your last page indicates the min and max loop temps.

Min looks good, max looks to low.

But it is a little hard to read.

Thanks. Min is 30 and max is 64.5. That's too low? Really?

[thenuke]

That is a good piece of equipment, dual capacity, variable speed.

What will they be using in the loop?

When you're asking what they'll be using in the loop, what do you mean exactly? What's actually running through the loop?

[thenuke]

And did you get the 55 year warranty on the loop?

I did not, I'm assuming by your phrasing that I should...

[energy star]

Gas cost $1.25?

[thenuke]

Yep.

[energy star]

At that price you would be better off with a high efficiency gas furnace. Is that Natural gas? Payback will be a long time with that gas price being so cheap. Just my .02

[weber]

When you're asking what they'll be using in the loop, what do you mean exactly? What's actually running through the loop?

What will they be using for freeze protection?

methanol?
ethanol?
pg?
enviranol?

There are differences in design for each, and is important to know.

[weber]

I did not, I'm assuming by your phrasing that I should...

Well, if you are using a certified company, and they are using the geolink pipe from waterfurnace, they should be offering a 55year warranty.

It goes with all of installs.

[thenuke]

What will they be using for freeze protection?

methanol?
ethanol?
pg?
enviranol?

There are differences in design for each, and is important to know.

Its methanol. I'll start looking around to understand the differences. And the installer will be using the GeoLink pipe, so we're good to go on warranty.

[energy star]

In your annual cost projections do I understand correctly that on the 2nd to last page of the posted anticipated costs, we are comparing an ultra high efficiency water furnace unit to a 92 percent furnace matched with a 13 seer A/C system (heatpump). I think the costs would be closer if the efficiency levels of the gas furnace were bumped up along with a higher efficiency A/C unit. Once that is done, run your costs.

Also in 15 years maybe 20 years what would the cost be to replace a geothermal system compared to a high efficiency conventional type system. If you have natural gas on site you should be using a gas hot water heater.

I know you love the Geo system, but it appears you are not comparing or mating it with a system that could be more efficient than the one he used as a comparison. Also you really need to weight the costs of the replacement unit you WILL need in 15-20 years. That all comes into play.
Why are they not using vertical loops? Is not The earth warmer vertically.

If you bump up the conventional systems efficiency then figure what you will be saving annually then add the cost of a new Geo unit (replacement) down the road you may find you are spending more on the Geo system.

2800 sq = 2-ton of cooling seems low to me. Does the company install conventional type systems? or do they specialize in geothermal?

My Water furnace rep once told me they do not hit a geographical location that has natural gas. Maybe this has since changed, but a buck twenty five for gas is pretty cheap.