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Jan 09
0

Questions for Prospective Geo System Designs

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New or retrofit? Both require a heat loss calculation or damn good estimate if retrofit. Retrofits often require duct upgrades if coming from a fossil fuel furnace. What is the size of home and size of property? This determines heat pump (HP) and loop size. Bigger homes always perform better with mulitple HP’s.

Location. Your precise address helps but often the nearest big-ish city is needed since not every little town is available for climate data. Water bodies, soil conditions, and local knowledge help too.

Forced air or radiant floors? Forced air is relatively simple but is hard to zone, radiant or hydronic systems require a mech room and many more parts but offer superior comfort and lower run costs.

Horizontal or vertical loops? Vertical is almost always better but usually more expensive but sometimes not. Deeper and fewer holes are always better. However vertical is cheaper in the very long run. Horizontals require a very large land area, anyone who says otherwise is cheating the laws of physics, good luck with that. I’m reluctant to design horizontals in an area of high cooling loads. What is the nature of the soil and subsurface? Water well drillers provide the best info here.

Geo contractor, DIY, or plumbing contractor? This question is a can of worms…..

Level of technology? Some clients want the latest in connectivity and variable speed everything. Others want simple and reliable. I’ve found the best approach is simple and reliable and spend the savings from the hi tech version on a bigger loop. The bigger the loop the better, everyone seems to want to save money here but undersized loops are the biggest mistake I’ve seen in 24 years of doing this.

However, I do love to see an internet connection to view HP functioning remotely.

The Geo Guy

May 13
0

Twisted?

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Around here we do things a little differently, but Twisted?

The first borehole geo system I ever saw hurt. Reason being I was the drillers helper and it’s hard work especially for a 150 lb scrawny guy.

Looking at the hole with 2 pipes randomly in it surrounded by grout which has a thermal conductivity ranging from near styrofoam all the way up to better than styrofoam, I figured there must be a better approach. There were methods to improve the TC of the grout (thermal conductivity) up from around .4 to .8 or better. A good TC in rock is maybe 2.0 so you get the point of the styrofoam. I started researching and formulating my own grout materials and even tried graphite, so messy.

At a trade show in Germany I saw a double U-tube for the first time. It uses spacers to hold the 4 pipes up against the wall of the borehole where the action is, so the grout material didn’t matter as much. I ordered some spacers and drilled a 600 ft hole. One single hole for a 5000+ sq ft home! The results were amazing and we did more and more of these. The only drawback was that it was a lot of work to arrange and get this much pipe down a hole.

Then I saw a Twister borehole heat exchanger and had to try this out. It seemed like a natural progression from the dU-tubes without the work. An improved quad U-tube with a twist! The manufacturer, agreenability.com claims 30% less drilling but my own results show even better.

Feb 25
1

Vertical Loops vs Horizontal Loops

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Horizontal loops are popular for a few reasons:

They are generally considered to be cheaper to install. This is not necessarily true.

Their performance is considered to be just as good as vertical boreholes. Wrong.

They can be squished closer together as in slinky loops. Dead wrong.

They can be economically installed at the time of construction since an excavator is already there. A maybe.

Drawbacks to Horizontal Loops:

Horizontal loops are always installed in the overburden layer of your

soil/property. This means the thermal conductivity of the soil ranges

from barely ok to abysmal. See the chart below.

rock and dirt

rock and dirt TC chart

We see from this chart that an average sand/clay/whatever horizontal overburden has a TC value of 0.5 whereas rock has a value of 1.5 to 2. This simple arithmetic alone should pretty much discredit anyone doing horizontal loops.

Any horizontal loop shallower than 20 ft still shows a seasonal swing whereas a borehole never does.

And here comes the last straw for cooling dominant systems… the heat dumped into a cooling dominant loop causes the soil to dry out and lose most all TC it may have had (unless you made provisions to irrigate it). I have measured cooling loops at 123 deg F !!!   A heating dominant loop on the other hand, sucking heat out of the ground, actually attracts moisture.

Horizontal Loops require a lot more space than you realize.

Regardless of what someone may claim, the laws of physics still supercede advertising claims. A responsibly designed horizontal loop actually requires approx twice the square footage of the home. I recently consulted on a project where the contractor for a 70 ton system for a 26,000 sq ft home decided to pile slinky loops on top of slinky loops in a deep pit. It should have been spread out over more than 2 acres.

Ever think of subdividing your property with a geo loop spread all over it?

Vertical Loops

Boreholes can be more versatile than commonly thought. 10 years ago TheGeoGuy installed a 5+ ton system for a 5,200 sq ft home with a single 600 ft borehole using double U-tubes in the driveway right next to the mech room. A very tidy low cost installation. Maximizing the value of a borehole (on top of the TC improvement) is where the savings in vertical loops occur.

1 hole maintaining 40 deg F loop temp for 10 years! That’s the way to save.

 

Feb 15
0

Loop Lengths and Depths

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More is always better!

“Less is a disaster” – Stan Marco

It seems that in geo design everyone is always trying to design the smallest loop possible to save money. Are they saving money? The answer is a clear NO.

My son the physicist says that I should quantify things instead of ranting, so here goes…

On the accompanying chart of a typical WaterFurnace unit, it shows 30degF and 40degF EWT, (entering water temp) and the accompanying heat output, 29,700 Btu/hr and 33,900 respectively. The longer loop length gives you a higher EWT.

At a typical 2500 hrs/year of run time, we get a difference of 4,200 Btu/hr x 2500 hrs = 10,500,000 Btu/year more heat. That was 10.5 million Btu’s! This translates to a reduced runtime of 10.5mBtu/yr / 33,900Btu/hr = 310 run hours/yr for the same load. Nice!

EPSON MFP image

310 saved runs hours/year cost 2.52kW (from the chart) x $0.15 (your local electric rate will vary) x 310 = $117.20 per year in savings plus a proportional increase in heat pump lifespan, approx 12.4%. It will actually be more as the heat pump will be running in a sweeter range, but I can’t quantify that one.

For a heat pump that costs $12,000 and lasts 20 years, (the loop lasts 50+) a 12.4% increase in lifespan is worth $1448, or $74.40 per year.

Combining the energy and heat pump savings you get $117.2 + $74.4 = $191.60 per year saved. Over a 20 year lifespan, this equates to a savings of $3832!

That said, one normally discounts future savings at a rate equal to the interest rate you’d earn if you were investing money in say, federal bonds. So, this savings should be worth less than $3832 in present day dollars. However, we can’t forget the price of electricity is increasing faster than federal bonds which will make the $117 yearly energy savings increase. That is, Year n savings is = $117.2 * (1+energy increase)^n/(1+discount rate)^n + $74.4/(1+discount rate)^n

Including all of these factors, and taking an electricity increase rate of 8%/year and a discount rate of 4%/year, we find a savings of $4,578! How much extra it will cost to make your loop 10deg EWT better is very site specific, but certainly less than the $4578 in savings.

And then, when the heat pump needs replacement, you’ll undoubtedly get the then more advanced model which can extract more heat. Uh-oh, now your budget loop is too small…the performance of your new more efficient heat pump is degraded right from its start.

Jun 05
0

Climate Control for Greenhouses & Grow Rooms

By | Blog, Featured Articles

Whether you have a greenhouse or indoor grow operation, whether for medical marijuana, recreational cannabis, or micro greens for restaurants, proper climate control is as vital as knowing how to grow your crop.

The levels of heating and cooling and dehumidification are from 4 to 10 times higher in a greenhouse or grow room than in a residential home application. This means some serious climate control equipment and design is required.

Greenhouses typically use fans and vents for cooling. This means all that heat energy is expelled and wasted only to be bought back at night for heating from your local utility. This energy can be saved and reused. Forget about humidity control and co2, gone with the wind via the fans.

In a closed grow room the lights do more than enough heating and the room needs to be cooled. When the lights go out the temp falls quickly and the relative humidity spikes causing fungus to set spores and spread fast. The lights should be ramped down in stages instead of all out to help the dehum system do its job more effectively.

This control of humidity and fungus may be the most critical function in closed rooms (and greenhouses) and yet is seldom addressed properly, actually almost never.

Many growers would install an air conditioning system which is largely ineffective overall and usually wildly miscalculated in size. Careful calculations and design should prevail, not guesswork.

Heat load and cooling load calcs should be done and a heat pump system can be used, either air source or ground source. The ground source can recover the energy for cheap night time heating but the most critical component of all is the installation of extra coils for humidity capture while simultaneously maintaining the desired temps. The size of the system must be as large as the kW load of the lighting minus the PUR and then adding the latent load of dehumidification. And then we should add a mixed air section to use free cooling when available.

Even then, without an electronic control strategy all the best equipment won’t function well. Manufacturers have built more efficient equipment but installers and end users still don’t get the delivery system up to date. The controls must be internet accessible so that remote monitoring and diagnosis is possible.

So now we have conditioned air for the plants, cooled, dried, heated, co2’ed, whatever is required at the moment… but how do we deliver it effectively? Simply blowing it into the room is a waste of all the above effort.

The GeoGuy designs climate control that dramatically increases the quality and quantity of your production and saves energy at the same time using science, physics and plant growing experience to get it right the first time.

In the next articles we’ll discuss advanced lighting, air delivery, vertical growing and maybe even aeroponics…

Jun 01
0

The High Cost Of Geothermal Systems

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The high cost of geo systems, a must read!

Hello — Glad to hear you’re busy – thanks for answering —

I installed my own ground loop & 4-ton Command Air in 1988. After a burn-out in 1998, I put in a new 4-ton Command Air w/scroll compressor. All the time hooked into my original loop, consisting of 4-each 500′ loops hooked in parallel, with two Grundfos pumps in series, giving me aprox 12 gpm. the compressor typically locks-out a few times in January, but this year it had been a plague, with me having to reset at least once a day — have been considering putting a 1 hour time delay triggered by the lockout relay.

I sent for a digital temperature probe. So I need to take some accurate temp and pressure drop measurements. After I get that done, I may need some serious advice as to how to proceed. My sense is that there is a lot of bad ‘expert’ info out there. I put in my original system (do-it-yourself) in 1988 for $3,599. My new pump & air-handler in 1998 was approx $4,000. Now, just to replace my heat pump (using my old air-handler) I got a quote of 10K!! Nobody wants to sell me direct any more — my wholesaler is apparently too rich!

The reason no one wants to sell me a unit ( and I see a lot of them for sale on EBAY) is that they are protecting their dealers, who are ripping-off the customer with outrageous prices. I think the high cost of putting in geothermal is killing the industry. The ROI is very long compared to an air-source system. Wells here are about 2K per hole.

The GeoGuy says:

Whoa here!
Ok, Dear Sir,
You have already answered your own questions. A heat pump should never trip out except upon something going wrong. Is that clear? I have to ask that again. A heat pump should never trip out,especially every day! Is that clear?
Your ground loop is seriously undersized, even catastrophically undersized, proof of which is you are on your third compressor, the first of which should still be running since 1988.

500 ft loops per ton is so inadequate, try a minimum of 800 ft depending on your local thermal conductivity.

And then your rant about prices…priceless.
I’ve been installing leading edge geo systems, not your typical ones, since 1998 and contractors struggle to get 20% markup on heat pumps, which often includes warranty allowance, overhead, delivery, etc because we have to compete with low cost furnaces and boilers. I agree prices are too high BUT:

Your anger should be directed to where it belongs.
In 1988 oil was $16 a barrel, gold was $400 on its way to $200, A brand new Honda Civic was $6,000 and a house cost $80k. A Boeing 747 was $60 million, now it’s $300 million. Blame your very own government for ruthlessly printing money and stealing your wealth through inflation, not your fellow working class trying to feed their family.

The reason no one wants to sell you a unit is that they will only get a warranty claim from you, not a profit. A big geo issue is training contractors to install properly sized systems so these issues don’t occur.

You could send me some system pics and $100 to my paypal account on my website and I would be able to advise you on how to add to your ground loop and rearrange your pumping arrangement to get you running in the sweet spot.

Let me know what the loop temps are. I’m guessing 24/28 deg F when they should be closer to 34/40. The delta T should be 6 deg F in most cases.

More later,

The GeoGuy.

May 28
0

Failed 6 Ton Open Well, Forced Air Geothermal System

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A reader sent pics and a description of his failed 6 ton open well, forced air geo system:

The GeoGuy responds…

I finally had a chance to get to this and don’t really have a good answer…
The workmanship from what I can see is bordering criminal and you should notify Climatemaster to have this jerks dealer status revoked.

It’s so sad that there are no licensing requirements for residential hvac in most areas.

Your mech room is very small I’m wondering what room we have to add some components…

You will need to add a closed loop to protect the HP from the skanky well water you have. This will take up some space.

Is there a zoning module installed? In other words you simply cannot open and close air dampers via thermostats on a heat pump without maintaining airflow through the unit. The different brands of thermostats suggest there is not. You may have to disconnect all the thermostats and let the ductwork run wide open.

Your well pump must deliver the required 13.2 gpm to the HP when it is running. This requires 1 1/4″ pipe. The solenoid valve must be connected downstream of the HP, not sure if it is…

If you deposit $100 to my paypal account on my site I can send you pics and recommendations on how to add the closed loop. For an additional 100 I can calculate and spec the sizes of the required heat exchanger, circ pump, piping, exp tank, flowmeter, etc. I have to bill for this as it will take some time and I have to payback my decades of learning all this the real way.

All this repair/upgrade work will cost possibly $2k to $5k, depending if you have to install a new well pump.

Cheers, the GeoGuy

Feb 23
0

THE LOW BID

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Beware of the low bid.

In the big league, when the bids come in, usually the lowest bid and the highest bid are tossed out. There is good reason for this. The value of a proposal is clearly not just the price, but what you get for the money. The client expects good value, professional workmanship, and a problem free relationship with the contractor/provider of the service. If there is a problem, it usually costs money to resolve and there goes the savings in choosing the low bid.  Checking out the references and the reputation of the contractor cannot be emphasized enough.

QUALIFICATIONS:

The qualifications of the geo contractor are very important. In the electrical world permits and licenses are clearly defined. In the plumbing world permits and licenses are clearly defined. In the hvac world it’s the Wild West. What are the qualifications of your low bid geo contractor? Is he a member of the CGC (Canadian Geoexchange Coalition)? Does he know what CSA 448 is?

The CGC develops training and standards for the advancement of geoexchange technology in Canada (and contributes to the rest of the world too). Your contractor should be a member of the CGC. If he isn’t, why not? Membership demonstrates that he is willing to be accountable to his peers and his clients. What trade qualifications do his employees have?

Aug 25
0

The Power of Geo

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Making Geothermal Projects Work. The core of the Earth is kept hot by radioactive decay while the surface is kept warm by solar radiation. Geothermal “energy” is extracted from the depths of the Earth while geothermal heating and cooling (now called geoexchange) is extracted from the surface of the Earth. This is why we refer to the Earth as our free solar energy storage system from which we can exchange low level energy at will.

Aug 24
0

What we normally can’t see…

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Geothermal Heating and Cooling is clearly visible when we use different eyes. On the left are 2 stacked 5 ton units in a greenhouse. On the right are 2 stacked 4 ton units in a home.

The Geo Guy can do energy audits like this infra-red imaging to find where your energy is going. WARNING: IR imaging shows how badly we build things here.