[Bldg-sim] Snow melt (UNCLASSIFIED)

Carol Gardner cmg750 at gmail.com
Fri Jul 22 14:51:56 PDT 2011


I was wondering how the snow melt system would work help you during the
summer months, unless you are up in the mountains somewhere. What about
preheating, or just heating, DHW as it would be a year round load?

On Fri, Jul 22, 2011 at 2:46 PM, David Eldridge <dse at grummanbutkus.com>wrote:

> Check the Oklahoma State Building and Environmental Thermal Systems
> Research Group -- there are a number of papers on various topics related
> to geothermal systems in hybrid, shallow, and other configurations.
>
> http://www.hvac.okstate.edu/
>
> There is also a great research project where snow melt was the primary
> purpose of the geothermal system, which is not quite what you guys are
> after but might offer some guidance.
>
> David
>
>
>
> David S. Eldridge, Jr., P.E., LEED AP BD+C, BEMP, BEAP, HBDP
> Grumman/Butkus Associates
>
>
>
>
>
> -----Original Message-----
> From: bldg-sim-bounces at lists.onebuilding.org
> [mailto:bldg-sim-bounces at lists.onebuilding.org] On Behalf Of Nick Caton
> Sent: Friday, July 22, 2011 4:26 PM
> To: Eurek, John S NWO; bldg-sim at lists.onebuilding.org
> Subject: Re: [Bldg-sim] Snow melt (UNCLASSIFIED)
>
> I will say I got really excited this past year about the isolated idea
> of combining snow melt with geothermal well field design...
>
> For those unfamiliar, well fields in this part of the Midwest (KS/MO/NE)
> historically heat up over the long haul, especially with intense
> equipment loading like John's situation...  fields installed decades ago
> commonly end up struggling and failing when the extreme summers roll
> around, sooner or later.
>
> The most common pre-emptive/patch solution I've seen to tackle this
> trend is to tack on (or set up infrastructure for) an exterior dry
> cooler to reject excess heat from the loop.
>
> I pushed hard recently to consider a "snow melt" loop (even if not used
> to functionally melt snow) as a better "free" means of keeping a
> well-field in balance annually, but the real trick is in how to set it
> up so that this extra loop it doesn't require active
> maintenance/monitoring... Making a location for horizontal loops like
> this is also a challenge in many cases where the land is not readily
> available or has future expansions planned.  Most clients out there,
> even those with motivated maintenance staffing, would really be best
> served with a "fire and forget" system that could handle itself decades
> down the road without requiring active monitoring/adjusting as the
> seasons change and temps swing. Ultimately, I haven't yet come up with
> any particularly great setup that I would consider fool-proof over the
> span of decades, but I'd be very interested if others have
> thoughts/details to share on how this might be achieved.
>
> Conceivably, and to your specific questions John, I'd speculate the
> actual controls would at a minimum need to define parameters
> establishing a range of "target" loop temperatures for the cooling and
> heating season (these would be based on 1st year loop simulations, to
> start).  The "melt" loop routed near the surface (or embedded in
> concrete where it might be safe), would be normally closed, but valves
> would open for circulation when the outside temperatures* are conducive
> to pushing the well field return temperatures in the desired direction.
> Done cleverly, you could push the system to permit water below the
> setpoint during the cooling season, and above the setpoint during the
> heating season as well (this behavior would potentially occur in the
> swing seasons - spring/fall).  I'm thinking the ideal controls would
> constantly monitor and take advantage of free heat rejection & free heat
> gains whenever applicable.
>
> * Another point to consider:  What temperatures are ideal to monitor for
> such a loop?  Outside air data may be easily available, but considering
> the lag in topsoil temps and depending on what you choose for the actual
> loop installation location you might do better to locate a sensor
> elsewhere... A loop underneath black asphalt getting will experience
> different temperatures than the same loop embedded in light-colored
> hardscape or simply under exposed topsoil.
>
> Northern climates might find the same setup of interest to primarily
> gain free heat gain to keep loops in balance, routing the secondary loop
> through building envelopes or similar massed structures that would pick
> up extra heat in the summer months.
>
> Suffice to say I find it an interesting topic - if anyone has ever come
> across a design guide or white paper on this subject I'd also be very
> interested to hear about it!
>
> ~Nick
>
> 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
>
>
> -----Original Message-----
> From: bldg-sim-bounces at lists.onebuilding.org
> [mailto:bldg-sim-bounces at lists.onebuilding.org] On Behalf Of Eurek, John
> S NWO
> Sent: Friday, July 22, 2011 3:30 PM
> To: bldg-sim at lists.onebuilding.org
> Subject: [Bldg-sim] Snow melt (UNCLASSIFIED)
>
> Classification: UNCLASSIFIED
> Caveats: NONE
>
> Modelers.
>
> One of my projects has server rooms which combined produce 143 MBH (more
> heat
> than some home furnaces) and the servers run all the time.
> I am designing a ground source heat pump system for the building.  The
> energy
> model shows that the geothermal well field is unbalanced by 522,500,000
> btu.
> I'm plan on using a snow melt system to get rid of the extra heat. (Snow
> melt
> is a nice by product, the goal is to balance the well field's annual
> load.)
>
> Has anyone designed this kind of system?
> I'm not really sure how to model it?
> I'm foggy on how to control it so I get rid of just the right amount of
> heat.
> Has anyone designed this kind of system?
>
> It is fun to get to design energy efficient systems and coming up with
> new
> ideas, but it is hard to do research on them.  (I know snow melt isn't
> new,
> geothermal isn't new, computer room cooling isn't new, but I haven't
> found
> any articles tying the three together.)
>
>
>
> John Eurek PE, LEED AP
> Mechanical Engineer,
> US Army Corps of Engineers
> Omaha District CENWO-ED-DA
> 1616 Capitol Avenue
> Omaha, NE 68102
> Phone: (402) 995-2134
> email: john.s.eurek at usace.army.mil
>
>
>
> Classification: UNCLASSIFIED
> Caveats: NONE
>
>
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-- 
Carol Gardner PE
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