snowmelt loops

harvey

I'm figuring a snowmelt job in the Chicago area. 3/4" PEX 50% glycol 150 btu /sq ft. Total area about 3200sq ft. What loop lenghts will be best? Thanks for your help

dconnors

Snowmelt

Why use 3/4 pex? depending on the application; you should be able to use 1/2 or 5/8 pex. I would run 300' loops.

Tim Doran_2

5/8 PEX

Is a good bit easier to lay down for sure. If you go ahead with the 3/4" here are some figures.
3200 sqft x 150 btu/sqft = 480,000 btu
25f delta T = 38.4 gpm
8" oc spacing
18 loops at 290 feet using 50% glycol = 13 ft/hd
Supply water temp = 137f Required surface temp = 36f

Tim D.

harvey

If I did use 5/8" PEX what should my loop length be?

Tim Doran_2

21 loops

at 250 feet, 8 inches on center. This bumps your ft/hd to 14.5


Tim D.

lchmb

will go with Tim on this

With one slight difference. In the pex manual it state's to use 6" loops for a high traffic area IE Hospital walkway's, old folk's home. Use 9" loop's in medium use issues, IE store front's, apartment entrances and to use 12" loops for residential. I would stick with the 5/8 pex though. I don't believe you would succeed with 1/2. I personally use the 9" loops..:)

Troy_3

Snowmelt

We use 3/4" at 9" OC 300' loops. For snowmelt we usually use pex-al-pex. It has a larger ID than pex. We are south of Buffalo NY. We do get some snow here and everyone that we have done works great.

Jed_2

And You'd

Tim Doran_2

Just a thought

Spacing is basically a function of desired output vs required water temperature.

Tim D.