Snow melt energy estimation?

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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

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134 South Fitzhugh Street Rochester, NY 14608

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bbishop at pathfinder-ea.com www.pathfinder-ea.com

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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

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

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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.

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...

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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

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Nick, you might be interested in some of the research posted at HVAC.okstate.edu about controls for ground-coupled snowmelt systems, in this case highway bridges in Oklahoma, including some monitored data.

DSE Mobile

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David,
Do you have an updated URL for HVAC.okstate.edu? The link below doesn't seem to work.

Christopher Jones, P.Eng.
Tel: 416.644.4226 * Toll Free: 1.888.425.7255 x 527

Chris Jones
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Hi Bill,
I looked into a snowmelt system for a fire station project in Aspen years
ago. I came across several papers about the use of geothermal heat pipe
systems for snow melt that have been applied in several installations -
particularly in Japan. Here's one link to a paper that covers the topic
pretty well.
Best regards,
Ellen

http://www.osti.gov/geothermal/servlets/purl/895225-RlOmlU/895225.pdf

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Thanks David, that did the trick. The research is here:
http://www.hvac.okstate.edu/research/smartbridge.html

Christopher Jones, P.Eng.
Tel: 416.644.4226 * Toll Free: 1.888.425.7255 x 527

Chris Jones
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