Click here to Find a Contractor in your area.
Welcome! Here are the website rules, as well as some tips for using this forum.
Need to contact us? Visit https://heatinghelp.com/contact-us/.

The cold, hard truth about snowmelt systems

HeatingHelpHeatingHelp Posts: 231
edited December 2017 in THE MAIN WALL
The cold, hard truth about snowmelt systems

Read the full story here


Comments

  • LMacNevinLMacNevin Posts: 1Member
    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 Posts: 2,316Member
    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 Posts: 802Member, Moderator, Administrator
    Great article, @Dan Foley. Thanks for sharing your knowledge with us!
    President
    HeatingHelp.com
  • cgdelzellcgdelzell Posts: 21Member
    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 Posts: 3,455Member
    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.
  • CanadaKeithCanadaKeith Posts: 6Member
    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 Posts: 3,455Member
    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.
  • kcoppkcopp Posts: 3,170Member
    Anyone ever done a "Hot Pour"..... embedded in asphalt?
  • ZmanZman Posts: 4,422Member
    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 rod_7hot rod_7 Posts: 9,030Member
    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
  • hmljhmlj Posts: 10Member
    "Oh cool, a snowmelt system would be great to have!"

    *Reads article*

    "Nevermind."
  • Solid_Fuel_ManSolid_Fuel_Man Posts: 1,196Member
    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.
    Master electrician specialising in boiler and burner controls, multiple fuel systems, radiant system controls, building controls, and universal refrigeration tech.
  • Mad Dog_2Mad Dog_2 Posts: 3,455Member
    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.
  • MikeJMikeJ Posts: 99Member
    @Dan Foley @Mad Dog @Zman What percent of glycol do you like to use in your snow melts? Do you use polypropylene?
  • ZmanZman Posts: 4,422Member
    50% for sure. Propylene
    "If you can't explain it simply, you don't understand it well enough"
    Albert Einstein
  • hot rod_7hot rod_7 Posts: 9,030Member
    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 Posts: 99Member
    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 Posts: 5,840Member
    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.
  • Mark EathertonMark Eatherton Posts: 5,840Member
    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 rod_7hot rod_7 Posts: 9,030Member

    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
  • 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.
  • SSJEFFSSJEFF Posts: 1Member
    Dan, I started researching snow melt systems today and this article was just what I needed. Thank you.
  • Erin Holohan HaskellErin Holohan Haskell Posts: 802Member, Moderator, Administrator
    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 Posts: 23Member
    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.
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!