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That's awesome.
 

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Show us the heating coils.
 

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Is it propane/gas/oil, electric, or Geo? No shoveling is awesome.

I inquired about installing a hot water loop under my new driveway back in 2008, as I was also having a Ground Source heat pump system done nearly the same time. AS it turns out, the extra cost of the heat pump sizing and the additional vertical well loop would have cost an extra $12,000, before installing the water coils under the driveway, and the costs of operation when necessary.
 

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Discussion Starter #9
Yes. It is new.
The driveway is heated with an antifreeze solution that runs through 5/8" PEX tubing attached to 2 to 4 inches of 100psi (Can withstand 100psi without deforming) foam insulation.

Then a layer of stone dust is put on top of the tubing and then two layers (one coarse, one fine) of asphalt, then finally sealed after curing in the summer heat for a few months.
The front walk has the bluestone directly laid on the stone dust.

There is also thermal separation on the edges of the slabs to avoid heat loss.

Currently, the control system is... All of the circulators plugged into extension cords, controlled by the switch on a surge strip, with the tempering being done manually (I love playing with it) while it snows.

The master operating control is a brand new Tekmar Wi-Fi injection pump control that gets impending storm info from the internet and turns itself on based on certain adjustable parameters.
The secondary control (for the smaller front walk zone) is a linked (to the primary control) separate system, so it acts like a zone. This way if we are in Florida, I can only heat the front walk so the Mailman doesn't trip (We like him, he brings bike PARTS!). There is also a snow sensor for sudden squalls or internet outage and two slab sensors so the systems don't overheat. The separate snowmelt setups (front walk and driveway) are only tied into each other via a glycol feeder /pressure maintainer, and share an expansion tank.
There is one oversize flat plate heat exchanger (130k btu and 300k btu) for each zone. So one can run independently of the other.

And, you are thinking... Holy shit, the boiler to drive that must be huge. Well, it should be. But I am driving all that and the house with one 145k btu (DOE output) Weil Mclain EG standard gas/water boiler. It is way past its limit and it shows. Barely puts out 140 degrees when all zones are up (7 in house plus 2 snowmelt). I swear I can hear the cast iron crying.
The planned boiler is an HTP Elite Plus of about 399k btu that modulates down 10 to 1. Let's see if I can weasel a boiler out of the rep.

And..... The system is piped so we can use the heat generated by the driveway (149 to 162 degrees F) in summer to heat our domestic hot water.. Thus getting our local Green seal of approval and keeping the blacktop fairly cool so it lasts longer.

The system of asphalt replacement is handled by peeling up the layers as usual, then re laying fresh stuff on top. Have done it on many of my earlier systems throughout the years.

I'd show pics of the manifolds, but the spaghetti wiring does not look professional. especially with all the lab meters on it checking performance.

Thanks for your interest.
This is what I do for a living.
 

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Damn you Smittty, someone always has to rub everyone's nose in it! :D Not only have I had to shovel, sometimes twice a day, today I was out with a steel railroad bar busting up ice to keep the bottom of the driveway from flooding. Okay, I'll admit it, I'm envious. Nicely done! Two thumbs up!
 

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Very nice!
 

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Discussion Starter #15
Just the driveway:

The embedded tubing cost is minimal. The driveway has about 1400 feet of tubing spaced at an average of 4 inches. The tubing cost is about 1.23 per ft. Then there is foam insulation, staples, sleeves. Total associated tubing material cost was about 6950.

The driveway preparation and masonry materials and labor was about 30k for proper prep of thermally isolated slab.
The masons fitted the insulation.

The interior manifold parts, heat exchangers, circulators, valves, fittings was just under 9700.

Controls, low voltage wiring, electrical circuit material are all onsite and the cost was 6400.
Electrical labor is a barter out (I can do it myself, but my friend Scott makes artwork out of electrical) with a value of 8k.

Antifreeze was 2900, but that was for both the walk and driveway.

At least my labor was free. Did the slab design (36hrs, there were issues), Laid the tubing (6 hrs, I've done this hundreds of times), Designed the self purging manifolds, figured pump curves, operating temperatures (18hrs ), sourced parts, built and installed manifold/circulator/heat exchanger system, tied it into the existing old system with an eye toward the next stage, did the temporary wiring.(43 hrs)

So, it was an exercise in a bit of overkill, but it has already sold another system with 3 others pending. And it has only snowed once significantly.

Hey, I could have spent the money on heroin.




Smitty, I have to ask..., what would a system cost for a 25' by 30' area? Material cost, I can handle the plumbing.
 

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Very nice smart sensor regulated system, and if you can claim it as a marketing expense it might be tax deductable . Probably makes you the envy of your neighbors too.
 
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