Click here to Find a Contractor in your area.
Welcome! Here are the website rules, as well as some tips for using this forum.

If you've found help here, check back in to let us know how everything worked out.
It's a great way to thank those who helped you.
Need to contact us? Visit https://heatinghelp.com/contact-us/.

The cold, hard truth about snowmelt systems

HeatingHelpHeatingHelp Posts: 301
edited December 2017 in THE MAIN WALL
The cold, hard truth about snowmelt systems

Read the full story here


4JohnpipePaul S_3Alan (California Radiant) Forbes

Comments

  • LMacNevinLMacNevin Member Posts: 2
    Great article Dan. My own experience coincides with yours.
    I'd never be embarrassed to offer a SIM system to any client, thinking it's a luxury. There are many reasons why a SIM system can be essential, even for non-luxury housing.
    The good news is, when it's not showing, SIM systems cost nothing to operate (unless you're idling!).
  • STEVEusaPASTEVEusaPA Member Posts: 4,134
    Thanks Dan, good stuff. Couple (really I could ask thousands) of questions:
    1. On your staircase design, I assume the concrete person forms the stair horses outside your piping, then has the riser forms connected end to end, floating across the piping (and braced)?
    ~~do you have a picture of it formed up~~
    2. On sizing, do you properly size based on your slab requirements, or are you upsizing to get more btu's thru faster. If you are, do you have a typical factor (10%, 25%, etc.).
    Thanks
    Steve
    steve
  • Erin Holohan HaskellErin Holohan Haskell Member, Moderator, Administrator Posts: 1,306
    Great article, @Dan Foley. Thanks for sharing your knowledge with us!
    President
    HeatingHelp.com
    kcopp
  • cgdelzellcgdelzell Member Posts: 22
    edited December 2017
    how about Honeywell IAQ with wifi and remote sensor? Did you ever install 4 way valves to reverse flow through slab?


  • For some people, a little bit of heat will break the bond between the paving and the ice, but some muscle power still needed.—NBC
  • Mad Dog_2Mad Dog_2 Member Posts: 3,464
    As usual, well-done, Dan. You've done many more than I, but I've been through the same trials
    & errors, rolling around in the snow and cursing!. We too had slab sensor failures and after that installed manual switches and timers to start ramping up the slab for a fast incoming squall.
    The biggest lesson I learned out of the gate on the first big one was that you will pay dearly trying to do the job "economically" for the client.
    Not having those extra valves, Spirovents, or heat exchangers may "bring the job inline"
    With the other bids, but YOU will be the one eating the hours & hours & hours of labor when
    There are problems. You may get the job and make the client happy, but you'll take a THRASHING. I'll end with this. There is no other
    heating system that is SO CLEARLY performance-dependent. With radiant, hot water or steam, a cool spot here or there can be tolerated or even overlooked, but when there is one six inch ribbon of snow remaining on an otherwise perfectly melted driveway, the phone calls, texts, and emails come in like a blizzard! Mad Dog
    To learn more about this professional, click here to visit their ad in Find A Contractor.
    kcoppPaul S_3Dan C.
  • CanadaKeithCanadaKeith Member Posts: 9
    Great article, thank you. Wondering what thickness of concrete or other material is typically installed on top of the piping? In other words, how far below the surface is the piping?
  • Mad Dog_2Mad Dog_2 Member Posts: 3,464
    On my projects, the tubing was pulled up during the pour of a 4" slab, then, pavers set in sand or a few inches of asphalt. So, 3 -5 inches below the finished surface. The Colorado Madman, Marl Etherton did my designs. Dan and the others can weigh in. Mad Dog
    To learn more about this professional, click here to visit their ad in Find A Contractor.
    kcopp
  • kcoppkcopp Member Posts: 3,497
    Anyone ever done a "Hot Pour"..... embedded in asphalt?
  • ZmanZman Member Posts: 5,827
    I don't believe you could "hot pour " without damaging the tubing. I have worked on systems that put the tubing in a sand bed under the asphalt. Have not seen one that works very well.

    I convinced the control guys to try out an HBX optical sensor in conjunction with a traditional slab sensor. We are hoping to be able to determine the rate of fall and density of snow and ramp the system accordingly. At ski areas, I see large scale (acres) fire up and cost the operators $100's an hour because of a light flurry or some snow that gets kicked on a sensor.
    "If you can't explain it simply, you don't understand it well enough"
    Albert Einstein
  • hot_rodhot_rod Member Posts: 13,313
    I have heard of flowing water thru the pex when asphalt is applied, but never tried it.

    Asphalt arrives somewhere around 275F depending on how much temperature it loses after leaving the plant up to 325F. So to be pex safe 200F max. you would need to scrub away 75 degrees or so.


    In theory some grades and cures of EPDM are rated to 170C, so the rubber tube could possibly handle a direct asphalt pour. The Watts Entran was once solar certified, knowing that collector stagnate well above 300F.

    I did some rubber tube snowmelt where we drove the concrete trucks over the tube to pour long driveways. The pressure gauge would bounce up every time a tire went over the tube. The tube carried a 800 psi burst at 180F!
    Bob "hot rod" Rohr
    trainer for Caleffi NA
    The magic is in hydronics, and hydronics is in me
    kcoppSolid_Fuel_Man
  • hmljhmlj Member Posts: 10
    "Oh cool, a snowmelt system would be great to have!"

    *Reads article*

    "Nevermind."
    Solid_Fuel_ManJohnNY
  • Solid_Fuel_ManSolid_Fuel_Man Member Posts: 1,973
    EPDM is an amazing material. Just has it's own application for sure. I'd imagine someone, somewhere has used soft copper in a hot asphalt pour for this. Who knows how long the copper would last with salts etc.
    Serving Northern Maine HVAC & Controls. I burn wood, it smells good!
  • Mad Dog_2Mad Dog_2 Member Posts: 3,464
    That question came up (tubing in asphalt) when I did my own driveway, but MY gut instincts said, don't risk it. Mad Dog
    To learn more about this professional, click here to visit their ad in Find A Contractor.
    kcopp
  • MikeJMikeJ Member Posts: 103
    @Dan Foley @Mad Dog @Zman What percent of glycol do you like to use in your snow melts? Do you use polypropylene?
  • ZmanZman Member Posts: 5,827
    50% for sure. Propylene
    "If you can't explain it simply, you don't understand it well enough"
    Albert Einstein
  • hot_rodhot_rod Member Posts: 13,313
    For freeze protection best to check the label on the glycol you chose, some are diluted, others are full strength.

    Some glycol suppliers will blend excatly the % you ask for.

    I use a Rhomar product that is 95% glycol and then blend it to the various requirements.

    A 35% for example has a burst down around -60, plenty adequate for most areas in the US.

    But also there is a point where it will turn to slush and no longer be "pumpable" with a centrifugal type circulator.

    The 35% has a slush around 0°. So if you want to melt below 0, then you would need a stronger mix.

    The key is to not over dose glycol % as pumping requirement goes up and heat transfer down, and of course the cost.
    Bob "hot rod" Rohr
    trainer for Caleffi NA
    The magic is in hydronics, and hydronics is in me
  • MikeJMikeJ Member Posts: 103
    Use to take care of a large facility, they had two 100 ton chillers with free cooling. A large data center.

    They were using the same condenser fans for the free cooling that would use for the a/c.
    There was a copper condensing coil in parallel with the refrigerant coils. When temperatures were right they would shut the chiller off and draw air across the coil filled with glycol. Then pump it down to Liebert Air Handlers in the Data center.
    They would cycle the chillers weekly, 100% back up.
    They were using 30% glycol.

    When I first took over the account, check the glycol level with a refractometer. Had a reading higher then I expected.
    Was very concern about this, the site is in Omaha NE and we get down to -20 in the winter.
    I contacted the the big wigs in Kansas City and ask them about it.
    They have sites all over the US.
    Talk to one of the engineers and learn about burst pipes, slush and the reason for not using more glycol then necessary.

    Took care of the site for 7 years with the 30% glycol, had to refill it a couple of times when pump seal would leak and the fluid would leak out.
    Must say never once had a problem with it not pumping.
    Have a chiller sit all week in January then the chillers would switch always pumped. It was a 40 HP pump :smile:

    After knowing all this, I put in a snow melt in a patio a while back I order the 40% glycol :wink: don't have the deep pockets the data center has if something goes wrong.





  • Mark EathertonMark Eatherton Member Posts: 5,843
    For the life of me, I don't understand why more people don't park a small refrigerant compressor, a pre heat storage tank and necessary mechanicals and harvest all of the free solar energy falling on the driveway when it's not melting snow. Seems to me, under the right circumstances, a person could harvest more FREE energy off of the slab, then the slab uses for melting snow on an annual basis... I know for a fact that Mari Andrettis olympic size pool is heated by his snow melted drive way in the summer. Their slab would probably last longer as well, because the heat that causes expansion is being relieved of its duty.

    Heck, a person COULD make water with one of these systems if they were so inclined... (see where I'm going with this?)

    Good article Dan.

    ME

    PS, The IKEA store in Denver (Centennial) Colorado uses their snowmelt system to reject excess heat out of the VBH loop field, so I know its feasible :-) There is also an office building in Aspen Colorado that uses its SIM for heat rejection that has received national awards for energy conservation, and no cooling tower.

    ME
    It's not so much a case of "You got what you paid for", as it is a matter of "You DIDN'T get what you DIDN'T pay for, and you're NOT going to get what you thought you were in the way of comfort". Borrowed from Heatboy.
    Solid_Fuel_ManCLamb
  • Mark EathertonMark Eatherton Member Posts: 5,843
    cgdelzell said:

    how about Honeywell IAQ with wifi and remote sensor? Did you ever install 4 way valves to reverse flow through slab?



    I have, and it worked like a champ. When the valve reversed, you'd hear the modcons idle back until cold water stated coming back, and then they'd ram p up again. It was 300' from the top tp the bottom, so we ran 300' circuits straight form the top manifold to the bottom manifold. You really couldn't tell the difference visually when it was up and running. If memory serves me, we had 3 different sections on this driveway, and only did the reverser on 1/3 of it, near the top. This is also where we tested the different insulation types below the slab. Great customer.

    ME
    It's not so much a case of "You got what you paid for", as it is a matter of "You DIDN'T get what you DIDN'T pay for, and you're NOT going to get what you thought you were in the way of comfort". Borrowed from Heatboy.
  • hot_rodhot_rod Member Posts: 13,313

    For the life of me, I don't understand why more people don't park a small refrigerant compressor, a pre heat storage tank and necessary mechanicals and harvest all of the free solar energy falling on the driveway when it's not melting snow. Seems to me, under the right circumstances, a person could harvest more FREE energy off of the slab, then the slab uses for melting snow on an annual basis... I know for a fact that Mari Andrettis olympic size pool is heated by his snow melted drive way in the summer. Their slab would probably last longer as well, because the heat that causes expansion is being relieved of its duty.

    Heck, a person COULD make water with one of these systems if they were so inclined... (see where I'm going with this?)

    Good article Dan.

    ME

    PS, The IKEA store in Denver (Centennial) Colorado uses their snowmelt system to reject excess heat out of the VBH loop field, so I know its feasible :-) There is also an office building in Aspen Colorado that uses its SIM for heat rejection that has received national awards for energy conservation, and no cooling tower.

    Plenty of opportunity to harvest solar. I think a HP system viability is driven by $$. Studies show average homeowners spend around $300.00 per year for DHW. Probably most of the snowmelt system owners really are not concerned or aware of how much or how little they spend on DHW.

    Heck in Colorado I suspect many of the large residential snowmelts are at homes that are barely lived in. The DHW load is mainly their recirc systems :)

    Bob "hot rod" Rohr
    trainer for Caleffi NA
    The magic is in hydronics, and hydronics is in me
    Turbo Dave
  • I work in an industry where slips and falls on ice are routinely the cause of or contributor to 5- to 6-figure worker compensation cases. Even with shoveling, plowing, salting, and all the training in the world people still fall. Being an industrial facility that uses as much energy as a small town with multiple 300 hp boilers the energy consumption is not even a consideration and these systems are very popular at employee entrances and walkways. Both hydronic and electric.
    Canucker
  • SSJEFFSSJEFF Member Posts: 1
    Dan, I started researching snow melt systems today and this article was just what I needed. Thank you.
    Dan Foleykcopp
  • Erin Holohan HaskellErin Holohan Haskell Member, Moderator, Administrator Posts: 1,306
    SSJEFF said:

    Dan, I started researching snow melt systems today and this article was just what I needed. Thank you.

    Thanks, @SSJEFF.

    @Dan Foley
    President
    HeatingHelp.com
  • willasdadwillasdad Member Posts: 23
    Don’t most heat pex pipe have an osmosis barrier to prevent air from penetrating into the system? I remember a 10k linear foot snow melt job we did and it was important not to even leave the pipe out in the sun too long, UV would ruin the barrier. I can’t imagine hot asphalt would play nice with that. 4 Half million BTU input boilers twined up. And one heck of a heat exchanger, all backed by a 5k gallon oil tank! They were gonna need all that oil as bubble wrap tarp was the only thing laid beneath. Standard at the time suppose.
  • GeorgeDGeorgeD Member Posts: 1
    I though this was a great article with some very practical installation tips. I enjoyed hearing about the DC area. I would never have thought people would do snow melt in DC but then again it is a very affluent area.
  • GeosmanGeosman Member Posts: 5
    Thanks for reposting your story. It was a fun read. Been there and done that also.....Lately I've been using a snow sensor made by Automated Systems Engineering. www.goase.com their model DS-224C seems to meet all the needs for an above slab sensor with 3 way control switch that allows for manual, auto, off operations and makes testing the system even in warm weather much easier. Like you, I also had bad luck with snow sensors and replaced the failed sensors on the project below with one from ASE.
    Asphalt projects are a pain and not something I would like to repeat. Back in 2001 I took on a project for a local physician with a very steep riverside property. Previously he would keep his car at the top of the hill up at the road if there was a prediction for snow or ice. Even venturing onto the snowy driveway was an invitation for fast downhill trip and into the river. The asphalt delivery truck was at 375 degrees. We ran full force water at 55 degrees through the PEX circuits alternating areas between those that had cooled to less than 180 degrees and diverting the flow to areas with active 375 degree asphalt placement. No trucks on the tubes only donkey carts, spread asphalt by hand and a small roller. The driveway was so steep there could be no insulation below that might produce a slide plane. All installation work was on top of crushed limestone and wire mesh to hold the tubes in place and provide a stable base for the asphalt. This drive was a hazard even with frost or a slight amount of frozen water from the hillside. Controls were set to cycle the glycol pumps when the outdoor temperature dropped below 35 degrees. The glycol temperature is monitored and the boiler fires to keep it between 35-40 degrees to prevent frost. A pole mounted ASE DS-224C snow/moisture sensor set into the landscape adjacent the driveway serves to override the frost control and allows the boiler to fire to 80 degrees to melt snow as it falls.
    So far so good; 19 years and still running. Having the frost control seems to help prevent freeze thaw action that would typically tear up most asphalt driveways.
    ratiokcopp
  • HomerJSmithHomerJSmith Member Posts: 923
    edited June 18
    willasdad--PexA is a crosslinked polyethylene pipe. There were three ways to create the crosslinking. What happens, as I was taught by a Rehau engineer, was that the UV in sunlight would unlink the crosslinking and the recommendation was to not expose it to sunlight longer than 15 days. The deterioration was in the pipe and not in the O2 barrier, as I understood it.
    DYI
  • hot_rodhot_rod Member Posts: 13,313
    Many of the non critical residential SIMs run for a few months or 1 season until the gas bill catches up with the owner🤭. Even the ultra wealthy 1%ers realize heating concrete in their seldom used second homes may not be a finnancily wise use of their not so hard earned dollars.

    If you are paying to loader and truck snow from your driveways, the money may favor SIMs
    Bob "hot rod" Rohr
    trainer for Caleffi NA
    The magic is in hydronics, and hydronics is in me
  • leonzleonz Member Posts: 332
    The heating system my father used in his carwash was natural gas fired using its own boiler and circulator and it utilized a 100% automotive antifreeze system buried in the entire concrete slab.

    The approach aprons of each car wash bay were a continuous slab on both the entrance and exits and the car wash bays themselves used in floor heat that was set at 160 degrees from what I remember of it.

    The monorail company recommended that the floor heating system be operated from October first to May first during the heating season to keep the slab and dirt pits warm.
  • JUGHNEJUGHNE Member Posts: 6,896
    What type of tubing was buried in the concrete?
Sign In or Register to comment.

Welcome

It looks like you're new here. If you want to get involved, click one of these buttons!