gshp in florida ac only

[AC_Hacker]

Originally Posted by rhino 660

anybody know about the cooling aspect of geothermal?

Joe,

Welcome to the conversation.

Geothermal pretty much started with cooling, and only later began to use ground for heating.

Here's a link to the main Geothermal page at Oklahoma State University, where it all started.

Here's a link to the page where they offer manuals. They are expensive, but there is no place I know of where you can get this information any cheaper.

I own a copy of CLGS Installation Guide (#21020):
(The "original" Installation Guide), and I think it is well worth the price.

From what you have said, it looks like you have a pretty good idea what you're doing.

I say full speed on the project!

It would be very helpful if you documented your project here on this site, with pictures and plenty of description of what you did.

Just imagine how helpful it would be if you found a thread right here where somebody had already done just the project you want to undertake!

That's how it works... only you get to be the first one to do a Trench Air Conditioning Project.

A couple of thoughts I have...

A single 750' run of 3/4 HDPE is going to develop a fair amount of friction. You can get the required 3 gallons of water per minute per Ton to flow thru the pipe (6 gpm for your application), but you'll have to use more pump power than otherwise. This extra power will come off of your efficiency.

If you run your two loops in series, you will totally have too much friction.

If you run the loops in parallel, it will be better, because of less friction.

This is the kind of thing that you would find in the CLGS Installation Guide. There you will find formulas for calculating optimum trench/pipe sizes, pump sizes, etc. You can do it by trial & error, but it doesn't hurt a bit to be informed before you begin to dig.

Personally, I think you have a winner on your hands.

Take lots of pictures so we can all benefit from your experience.

> my concerns really are with adapting my existing a/c unit any thoughts?

You indicated you have questions about converting your existing heat pump, but you weren't so specific what those questions were.

Please clarify...

Also, as Xringer correctly identified:

Originally Posted by Xringer

...some of that heat you are pumping into the ground might built up after a while...

So even though you don't have plans to heat with your GSHP in the winter, any removal of heat from the ground will be better you in the summer cooling cycle.

For instance,

• use some of the ground heat to heat your hot water, or better yet, divert the heat to a water heater before it gets to the ground. (get your water heater outside the house envelope. it is a summer heat source.)
• if you have the space, you could pump hot air through a small spare room where you have clothes hanging for drying, giving you a GSHP dryer.
• not unrelated, if you are very clever, you could divert some of the cold refrigerant to chill your food, and eliminate the refrigerator as a summer heat source.

...additionally, I would imagine that your house is single story, slab on grade, without a lot of natural shading, dark colored comp roof, am I close? If you painted the roof with a white heat-reflecting coating it would help you, if you put solar panels on the roof, they would offset some of your electricity use and provide some shade, reducing the amount of work your heat pump will be doing. Along these lines, there is a type of solar collector called 'thin film' that costs a good bit less per watt to install, but occupies twice the surface. In your case, this might be an additional benefit, because it would offer even more sun shading.

...if your house happens to be cinder block, and you're thinking about insulating, put it on the outside of the masonry walls... 2 inches of foam would work wonders.

Right now, it is cold in Oregon, I envy you your cooling problems!

Best of Luck,

-AC_Hacker

[rhino 660]

Originally Posted by AC_Hacker

Joe,

Welcome to the conversation.

Geothermal pretty much started with cooling, and only later began to use ground for heating.

Here's a link to the main Geothermal page at Oklahoma State University, where it all started.

Here's a link to the page where they offer manuals. They are expensive, but there is no place I know of where you can get this information any cheaper.

I own a copy of CLGS Installation Guide (#21020):
(The "original" Installation Guide), and I think it is well worth the price.

From what you have said, it looks like you have a pretty good idea what you're doing.

I say full speed on the project!

It would be very helpful if you documented your project here on this site, with pictures and plenty of description of what you did.

Just imagine how helpful it would be if you found a thread right here where somebody had already done just the project you want to undertake!

That's how it works... only you get to be the first one to do a Trench Air Conditioning Project.

A couple of thoughts I have...

A single 750' run of 3/4 HDPE is going to develop a fair amount of friction. You can get the required 3 gallons of water per minute per Ton to flow thru the pipe (6 gpm for your application), but you'll have to use more pump power than otherwise. This extra power will come off of your efficiency.

If you run your two loops in series, you will totally have too much friction.

If you run the loops in parallel, it will be better, because of less friction.

This is the kind of thing that you would find in the CLGS Installation Guide. There you will find formulas for calculating optimum trench/pipe sizes, pump sizes, etc. You can do it by trial & error, but it doesn't hurt a bit to be informed before you begin to dig.

Personally, I think you have a winner on your hands.

Take lots of pictures so we can all benefit from your experience.

> my concerns really are with adapting my existing a/c unit any thoughts?

You indicated you have questions about converting your existing heat pump, but you weren't so specific what those questions were.

Please clarify...

Also, as Xringer correctly identified:



So even though you don't have plans to heat with your GSHP in the winter, any removal of heat from the ground will be better you in the summer cooling cycle.

For instance,

• use some of the ground heat to heat your hot water, or better yet, divert the heat to a water heater before it gets to the ground. (get your water heater outside the house envelope. it is a summer heat source.)
• if you have the space, you could pump hot air through a small spare room where you have clothes hanging for drying, giving you a GSHP dryer.
• not unrelated, if you are very clever, you could divert some of the cold refrigerant to chill your food, and eliminate the refrigerator as a summer heat source.

...additionally, I would imagine that your house is single story, slab on grade, without a lot of natural shading, dark colored comp roof, am I close? If you painted the roof with a white heat-reflecting coating it would help you, if you put solar panels on the roof, they would offset some of your electricity use and provide some shade, reducing the amount of work your heat pump will be doing. Along these lines, there is a type of solar collector called 'thin film' that costs a good bit less per watt to install, but occupies twice the surface. In your case, this might be an additional benefit, because it would offer even more sun shading.

...if your house happens to be cinder block, and you're thinking about insulating, put it on the outside of the masonry walls... 2 inches of foam would work wonders.

Right now, it is cold in Oregon, I envy you your cooling problems!

Best of Luck,

-AC_Hacker

i bought the slinky install guide when i heard you mention it in your other thread (awaiting arrival) i want to get the book you got but i have to wait untill we have another install job as work has been hit or miss.

i will most defiantly take lots of pics and give as much info as i can like you have. thank you by the way

i plan on running the loops in parallel

my questions on the condenser hookup,
i guess mainly the controlling of the loopfield pump
should i use the fan power to run the loopfield pump and not pre circulate and circulate after the heatpump ran to chill the loop?


im thinking of relocating the heat pump into the garage (its outside on the other side of the house.

after i sell my truck i plan on doing 2 kw of solar pv
and doing windows
i built my own solar collector for SHW and will install it after the pv install (code nazies dont like home made stuff)

you are very correct about my house cbs construction
i would do the white roof but im not sure on the deed restrictions where i live
and looks lol i have thought of it before though.

i do have an extra layer of insulation in the attic my elec bill high in the summer is $170 and low in the winter is $56 so my plans are to pretty much eliminate my bills also i am only 23 so i think i may be the youngest person to do geothermal

[AC_Hacker]

Originally Posted by rhino 660

...my questions on the condenser hookup,
i guess mainly the controlling of the loopfield pump should i use the fan power to run the loopfield pump and not pre circulate and circulate after the heatpump ran to chill the loop?

I understand the logic behind a heating system that would wait until the plenum was up to temp to turn on, and wait until the plenum's heat was extracted to turn off the fan, but in your case, when the compressor goes off, no more heat will be transferred, so I can't see that there's any advantage in continuing to circulate water in the loop... ditto pre-circulation.

Originally Posted by rhino 660

after i sell my truck i plan on doing 2 kw of solar pv
and doing windows i built my own solar collector for SHW and will install it after the pv install (code nazies dont like home made stuff)

Wow, good going with the solar, Joe! With your eco-renovations, you'll probably be able to sell electricity back to the power company, even while you're running your heat pump.

Originally Posted by rhino 660

you are very correct about my house cbs construction i would do the white roof but im not sure on the deed restrictions where i live and looks lol i have thought of it before though

I can't comment on deed restrictions, but I can speak favorably about aluminum shingle roofs. I have that type on my house, its been on for about 20 years or so. Looks like it was installed a couple of years ago... and I know it'll look just the same twenty years from now. I went with green painted aluminum. I certainly wish I had gone with 'mill finish' (plain unpainted aluminum), it would have been a superior heat reflector. It's become expensive to buy, but I think that there's an opportunity for DIY there too. I don't know how close you are to the ocean, salt air might be a deal breaker.

Originally Posted by rhino 660

...i am only 23 so i think i may be the youngest person to do geothermal...

I think most people do geothermal when they are later in life and have saved up the money for the big expense of geothermal installation.

You are really smart and have the gumption and knowledge to DIY your own system.

...that puts you way ahead of the game.

Good Luck!

-AC_Hacker

[rhino 660]

well seeing as i have i have personally installed over 100KW of solar i think its time i get a system of my own.

thank you for the compliments

one more question in your loopfield after the temp leveled out from running a few hrs there was a 10* rise in loopfield temp as i remember, so i was thinking if that happened in my system it would hurt my cop quite a bit. 70* rises to 80* although 80* is better than 90*-100* my boss had said something about this which had me second guess myself is all maybe i should put another 800' roll underground just to be safe i like over kill

[AC_Hacker]

Originally Posted by rhino 660

...one more question in your loopfield after the temp leveled out from running a few hrs there was a 10* rise in loopfield temp as i remember, so i was thinking if that happened in my system it would hurt my cop quite a bit. 70* rises to 80* although 80* is better than 90*-100* my boss had said something about this which had me second guess myself is all maybe i should put another 800' roll underground just to be safe i like over kill

I think you are referring to my initial borehole test. Yes, it was interesting that I never reached a 'balance point'.

There used to be a saying that, "a man can't have too much money or too fast a horse." I suppose the same can be said about loop fields. All things being equal, a bigger loop field will yield higher COP. The limiting factor is usually the cost of paying someone to install it for you. If you're doing it yourself, you might as well go for the gold.

My little loop field is much smaller than yours, it is yielding useful heat and the temperature has dropped (since I'm extracting heat). Originally, it started out as 51F and after running my little heat pump 24-7 for about three months, the temperature dropped to around 37F, give or take. Since I put the thermostat the loop temp has risen to the low forties. Part of that is due to the shorter duty cycle, part to the fact that the weather is getting warmer.

In actual practice, I wouldn't expect to extract heat continuously, and this is where I expect the insulation project I am doing to save my bacon.

I still have room to do some more boreholes, if I need to.

But if you have the equipment at your disposal, by all means trench away. It will take more gumption to come back later, trench & fill and patch into your existing field.

The cost of the HDPE is a pretty small part of the total project.

If you have three trenches in parallel, your pump motor power requirement will also be reduced, to obtain the same gpm/Ton. This alone will raise your COP.

There is a strategy to employ when you do your manifold, having to do with first-in, last-out, that will make your loops self-balancing. I'm quite sure your slinky book will give you info on this.

You'll also want to be mindful of potential dissimilar metals corroding due to galvanic action. The less expensive pumps are cast iron... if you don't have any other kind of metal in your loop (don't forget your heat exchanger), you are fine. If you have any brass, your pump will need to be brass or stainless. I think stainless & iron are ok, but you better double-check that one. I know that brass & stainless are ok together.

Since you are in Florida, no need to worry about antifreeze.

-AC_Hacker

[rhino 660]

thank you for all the pointers and info
in a few weeks ill order all the parts i need
i got the slinkey install book just need to look it over

[rhino 660]

i talked to an ac shop today and he can sell me the base model climate master gshp 2 ton unit for around $1300 + tax then the one with the 2 stage compressor is around $4000 but still way better deals than online
also he said he would size my slinkey loop feild for free i just need to get a heating cooling demand test done (forgot the name) is there an online program that does this? thanks

[AC_Hacker]

Originally Posted by rhino 660

...he said he would size my slinkey loop feild for free i just need to get a heating cooling demand test done (forgot the name) is there an online program that does this?

What you are looking for is a heat load calculator.

...or in your case an Air Conditioning Load Calculator.

Try two or three free ones and see if they are in agreement.

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There's a document that is part of the industry standard literature that calculates heat load in great detail. The document is called "Manual J".

Here is a link to "Manual J speedsheet".

You'll need Excel to run it... I opened it in Gnumeric and it seem to work OK.

You'll also need a tutorial or book to use it. Try here...
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Build It Solar has a calculator but it's only for heating.

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You might also search the web for Air Conditioning Load Programs, and see if any have a trial period. That might do it.

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If all else fails, try asking someone in your neighborhood who has a similar sized house, with similar insulation, etc. what size A/C do they have?

Ask about five people, you should have a pretty good idea by then.

If you built a loop field for a three ton unit, and then used that loop field on a two ton unit, no harm... but not the other way around.

Does that help?

-AC_Hacker

[rhino 660]

im back in town for a week ive been all over the east coast installing solar in the past few months we have done a little over a 100kw. im ready to do my gshp im ordering the pipe in the morning and in a few weeks ill go pick up the climate master

[rhino 660]

also i think im going to paint my roof white on the south side so the attic wont get so hot like you said i really like that idea