Snow melt piping design

CBRob

I'm working on a snowmelt project in a cold snow Colorado location. Using a Triangle Tube solo 110 boiler.
Ive been looking at differnet diagrams on how to get the heat to the slab.
Some include low loss headers or heat exchanges, others just a primary secondary loop.

any concern with a thermal shock to the boiler when using loops? any real benifit to a low loss header here?

The boiler will be dedicated to just snow melt for now, but would be nice to have an option to use it with a Smart DHW tank i the future.

I'm using all tekmar controls with the system.
720 sg ft of 5 inch thick slab. rebar on chairs, 3/4 pex barrier at 10" spacing. 3 runs of less than 300 ft. slab is on 2" of blue dow board

CBRob

a basic primary secondary loop

Zman

Any primary/secondary piping arrangement should work. Closely spaced Tee's are the least expensive.

The TT110 is OK with 50% glycol straight though with no heat exchanger. I would probably go with an indirect other than the smart just because of the extra volume the Smart has and the expense of glycol.

Guessing by your handle, are you in Crested Butte? Don't overlook the altitude derate in your calcs. A TT110 will probably work but will struggle to come up from a cold start.
Lochinvar boilers are factory tested in Breckenridge at 9,600'. They derate a little less that TT and have great local support. The WHB155 would be worth looking at.

FYI Veissman tests in Leadville at 10,000' I have not found there support to be as good.

HomerJSmith

Colorado? Isn't that like somewhere in the mountains?

Be aware that altitude does affect the BTU output of the boiler when you do a combustion analysis. What is the boiler output ?

Are you sure you have enough BTU's for an efficient snow and ice melt augmentation sys, and DHW? Any future concerns that should be addressed now?

Yes, a low loss header is always better than a tight one. Thermo shock is not a problem.

The loops should be about 2" below the surface of the slab.

Zman

@HomerJSmith
Yes, Colorado is that mountain range along the Mexican border where the new wall is going

For residential driveways and other non critical areas using 125 btu/ft (boiler output) usually works well.

The Triangle Tube 110 will put out 85,690 at 9,000' That works out to 114.25 btu/ft. It will melt but have trouble under some conditions.

I have seen systems sized at 85 btu/ft work pretty well if there is adequate slope and tubing is up in the concrete like you recommended, not on the bottom. Going that low is not a good idea as you are leaving a lot to chance.

Big commercial systems are often designed for >200btu/ft. Those systems melt the snow as it lands. If you watch the gas meters it makes you dizzy

SeanBeans

@Zman do these snowmelt jobs account for the melted snow/water accumulating at the bottom of the slope?

Zman

@SeanBeans , drainage is super important as it takes a great deal of energy to evaporate all the water. I prefer area drains to trying to divert to landscaping.

CBRob

Thanks Guys. My concrete crew did a great job of setting the tubes and rebar mid slab. The slab is pretty thick at 5 to 5.5 inches, but it should help it carry the weght of vehicles and spread it over the foam.
The driveway has nice drainage and should not see any standing water at all.
We have 720 sf total, r10 under it and edges.
As mentioned, yep Crested Butte CO 9600 ft above sea level.
Not sure about boilers, but combustion engines lose about 3% per 1000 ft.

Of the 720 ft, about 100 of that is covered by roof. Its still tubed at the same spacing as the rest of the slab. 3/4 bluefin barrier pex.

I was worried Id be doing this install on my own as we have a building boom going on here and a shortage of contractors. I just talked on of our local plumbers into doing the boiler install for me. I ran the pex myself.

The idea of being able to use this with a DWH was an after thought. The have 2 side by side 75 gallon gas water heaters that currently provide water to the house. Only a 2500 sf house with 3 baths.

Id suggest they replace them and upgrade now but they are only a few years old... and the price tag on just the melt system is big.

My plumber is a fan of TT, hates working on Viesmanns
He's waiting on parts for a vitoden 200 for another job of mine.

CBRob

Concrete and pex

STEVEusaPA

Good call w/plastic on the house while placing concrete...

Zman

You should be good. The triangle tube should run about 95% efficient melting snow and the derate is 2% per thousand. That is where the 114.25 btu/ft came from. You should melt just fine with that setup, tubing, insulation and drainage look great. I would suggest manually putting it in storm mode to preheat the slab when the big dumps come. You can do Indirect off that boiler in the future. Just activate DHW priority and it will take a break from melting snow to heat your water.