[Bldg-sim] Snow melt energy estimation?

[Nick Caton]

I would simply add/caution from what I've seen that you may encounter a wide range of answers for the same system/location based on controls alone.  If at all possible, you might try to get your hands on the system specification and/or submittals first, if available.

Controls can be as simple (wasteful/dummyproof) as a timer/relay system, operating broadly for the cold "season."  Controls can also be much more sophisticated (efficient/more-parts-to-break), entailing separate drybulb and moisture sensors in the slab and/or on the building to ensure operation only when the pavement is sub-freezing AND there's precipitation.  There also exists cycling controls to only run for a few minutes at a time, for scenarios when 100% on is much more than enough.

>From a modeling perspective, things only get more complicated if you aren't talking electric mats/cabling.  Hydronic snowmelt systems, particularly tied into other heat rejection systems (towers/ground fields*), are a whole 'nother ball of wax as far as modeling challenges go, but are definitely of interest for a "green" focused project, particularly if you could nab credit in a LEED environment for re-using such heat productively over an electric system (sounds like a shaky proposition though as I consider/type this).

Hope that doesn't complicate your query any further than a dedicated Handbook chapter on the subject!

Best regards,
~Nick

* Million dollar idea?:  I wonder if anyone has explored how or if hydronic snowmelt systems tied to ground well loops could be productively interfaced with each other to automatically offset the annual ground heat creep over time in heating-dominant climates like ours...

[cid:489575314 at 22072009-0ABB]

NICK CATON, P.E.
SENIOR ENGINEER

Smith & Boucher Engineers
25501 west valley parkway, suite 200
olathe, ks 66061
direct 913.344.0036
fax 913.345.0617
www.smithboucher.com

From: Bldg-sim [mailto:bldg-sim-bounces at lists.onebuilding.org] On Behalf Of Bishop, Bill
Sent: Friday, May 16, 2014 10:12 AM
To: Chris Baker; cjones at halsall.com; bldg-sim at lists.onebuilding.org
Subject: Re: [Bldg-sim] Snow melt energy estimation?

Wow! An entire 20-page chapter on Snow Melting and Freeze Protection. Thanks Chris, and Christopher! And thanks, ASHRAE.
~Bill

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From: Chris Baker [mailto:chrisb at twgi.com]
Sent: Friday, May 16, 2014 10:41 AM
To: Bishop, Bill; bldg-sim at lists.onebuilding.org<mailto:bldg-sim at lists.onebuilding.org>
Subject: RE: Snow melt energy estimation?

Bill,

2011 ASHRAE Handbook-HVAC Applications section 51 walks through a method that estimates energy consumption. If it's not in the ASHRAE handbook, I'm pretty sure you don't need to know it.

Chris Baker
952-938-1588

From: Bldg-sim [mailto:bldg-sim-bounces at lists.onebuilding.org] On Behalf Of Bishop, Bill
Sent: Friday, May 16, 2014 9:35 AM
To: bldg-sim at lists.onebuilding.org<mailto:bldg-sim at lists.onebuilding.org>
Subject: [Bldg-sim] Snow melt energy estimation?

Up here in the Empire State, building designs sometimes incorporate heating systems in the exterior walkways for melting snow (for safety, but also so people don't have to go outside and shovel the snow). Even "green" buildings are not immune to this design feature. Don't get me started.
Anyway, does anyone have a handy calculator for estimating the energy for this process load? I would think you could get a rough estimate just based on annual snowfall for a given location. If you have the time and feel like creating one on your own, I will reward you with a custom popart eQUEST model in the shape of a subject of your choosing.

~Bill

William Bishop, PE, BEMP, BEAP, CEM, LEED AP | Pathfinder Engineers & Architects LLP
Senior Energy Engineer

  [cid:image007.jpg at 01CF70F4.66E9E750]



134 South Fitzhugh Street                 Rochester, NY 14608

T: (585) 698-1956                        F: (585) 325-6005

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