News   GLOBAL  |  Apr 02, 2020
A Message to Our Readers
 9.7K     0 
News   GLOBAL  |  Apr 01, 2020
EarthCam Time-Lapse Documents Rafael Viñoly-Designed New Stanford Hospital Construction
 41K     0 
News   GLOBAL  |  Apr 01, 2020
Resort Town
 5.5K     0 

kcantor said:
i hope their interest has been piqued rather than peaked... :)

as for the snow melting, i wish it were that simple in our climate. :(

if you're going to try and melt the snow, there has to be some method and some place for the water to drain. it's pretty easy to add a trench drain at the bottom of a ramp using a snow melt mechanism (usually glycol loops in our climate but sometimes electricity) but relatively flat areas such as sidewalks can be particularly problematic when windrows etc. impede the drainage flow. the same issue will arise in the direction of the sidewalk where any nominal heaving or shifting of slabs will retain that water only to see it freeze into a solid sheet. wind drifts will create a similar problem, particularly once an ice bridge has formed on top of the melted water which happens often and quickly with our prevalent nw winds. at that point, clearing becomes much more difficult because everything is anchored by ice rather than just snow pack.

as for adding those iron filings, they will soon rust and spall the surface of the concrete they're embedded in which is why warehouse slabs now use stainless steel (which is considerably more expensive) or polypropylene fibers now that asbestos can't be used. i would also be interested to know how you would propose to deal with expansion joints and cracks and the inevitable repair and replacement of sections for servicing and new construction etc. without impeding your current flows.

at the end of the day, nothing beats good snow removal well done by hand and/or equipment. it's also much friendlier to chat with your service provider than with a hidden current.
Click to expand...

Actually the developer interest was piqued before I started writing these articles; it has now peaked to the point of forming a company to move forward with the concept with a formal proposal to the City (not that it will go far with the current administration). We are currently talking to a third developer whose interest has been piqued. Three architectural/planning firms will be involved in developing the proposal -- my firm -- Dezign2the9z, Inc. (SoCal), Douglas Cardinal Architects (Ottawa), and J. Murray McCombs, Urban Planner (Washington, D.C).

As to the iron-filings project for snow removal -- several points that were either not stated or were misread in the foregoing posts. The iron filings are mixed into a matrix of decomposed and crushed granite (not asphalt or concrete) along with a binding agent so they would not be exposed to the atmosphere (generally) and therefore would not rust (same kind of embedment that you would find with reinforcing steel in concrete). The snow falling on the surface does not "melt"; it "sublimates" rejoining the atmosphere -- so in the experiments that have been done so far on bridges in Montana with conventional pavement samples have not resulted in any liquid run-off. The effect is similar to those early winter snowfalls where the crystals land on warm pavement and, rather than melting, sublimate and return to the atmosphere. We hope to experiment with this in the late fall early winter to verify results for Edmonton (for other projects that we are currently working on). Of course there would be access points with slabs that would be removable for underground access, but, like asphalt, there would be no control or construction joints, typically, because the slurry would be more "plastic" than concrete formations.

At this point the whole project is a "what if" concept, but it may not stay that way.
 
archited said:
A further comment on dispelled air from adjacent buildings that would be exhausted under the pedestrian sidewalks... certainly this air would have to go somewhere beyond just "nesting" under the walkway. The air would be filtered, or course, to remove particulates and grease. But the residual air would still have building odors and so the aroma of restaurants (most notably) would be wafted onto the street through grills at the outer edge of the sidewalk -- the aroma of bakeries, of coffee shops, of ethnic specialties would all spill out onto the street (in some instances it would be Phở King amazing). Not only that, but curbside, on those exceedingly cold winter days when the exhaust and humidity that typically comes off buildings creates huge plumes of white "clouds", in this instance the plumes would rise from the street creating a mystical aura along the sidewalk that would turn the "worst" days of winter into something spectacular. And the same grill that allows spent exhaust air to escape could also serve as the entry opening for a rain gutter system (double duty). The cold-days plume would also crystallize on adjacent plant-groupings affording that wonderful winter-wonderland glaze that occasionally visits Northern 'burbs.
View attachment 262053View attachment 262054
Click to expand...
wouldn't those "cold day plumes" also condense onto any adjacent building surface (particularly windows and frames or sunshades etc.) or lamp standards and overhead lines with the inherent hazard of either damaging those elements or damaging what's below them as that ice inevitably falls?
 
archited said:
Actually the developer interest was piqued before I started writing these articles; it has now peaked to the point of forming a company to move forward with the concept with a formal proposal to the City (not that it will go far with the current administration). We are currently talking to a third developer whose interest has been piqued. Three architectural/planning firms will be involved in developing the proposal -- my firm -- Dezign2the9z, Inc. (SoCal), Douglas Cardinal Architects (Ottawa), and J. Murray McCombs, Urban Planner (Washington, D.C).

As to the iron-filings project for snow removal -- several points that were either not stated or were misread in the foregoing posts. The iron filings are mixed into a matrix of decomposed and crushed granite (not asphalt or concrete) along with a binding agent so they would not be exposed to the atmosphere (generally) and therefore would not rust (same kind of embedment that you would find with reinforcing steel in concrete). The snow falling on the surface does not "melt"; it "sublimates" rejoining the atmosphere -- so in the experiments that have been done so far on bridges in Montana with conventional pavement samples have not resulted in any liquid run-off. The effect is similar to those early winter snowfalls where the crystals land on warm pavement and, rather than melting, sublimate and return to the atmosphere. We hope to experiment with this in the late fall early winter to verify results for Edmonton (for other projects that we are currently working on). Of course there would be access points with slabs that would be removable for underground access, but, like asphalt, there would be no control or construction joints, typically, because the slurry would be more "plastic" than concrete formations.

At this point the whole project is a "what if" concept, but it may not stay that way.
Click to expand...
sorry... i thought you were proposing to transmit enough energy through those iron filings to melt the snow as that would actually take less energy than trying to keep the surface clear just through sublimation which is more energy intensive than melting it. i am familiar with the process but it relies an sunshine to provide the energy and works best with dark pavement that can first absorb and then release it. that storage capability is quite short-lived and can generate black ice when there is insufficient heat to complete the process (i.e. overnight). if it does get past the "what if" phase and you need some test parcels for trials and monitoring let me know and i'll see if i can assist in finding some for a long enough period to provide some tangible results.
 
Last edited:
kcantor said:
wouldn't those "cold day plumes" also condense onto any adjacent building surface (particularly windows and frames or sunshades etc.) or lamp standards and overhead lines with the inherent hazard of either damaging those elements or damaging what's below them as that ice inevitably falls?
Click to expand...
That is why I stated that the exhaust would be curbside at the far end of a "boardwalk" some 5 metres away from the nearest building wall and typically adjacent to a planting. I appreciate that it is difficult to visualize without referencing sections and 3-d renderings.
 
kcantor said:
sorry... i thought you were proposing to transmit enough energy through those iron filings to melt the snow as that would actually take less energy than trying to keep the surface clear just through sublimation which is more energy intensive than melting it. i am familiar with the process but it relies an sunshine to provide the energy and works best with dark pavement that can first absorb and then release it. that storage capability is quite short-lived and can generate black ice when there is insufficient heat to complete the process (i.e. overnight). if it does get past the "what if" phase and you need some test parcels for trials and monitoring let me know and i'll see if i can assist in finding some for a long enough period to provide some tangible results.
Click to expand...
No... that is not the process at all -- the sun and its energy does not fit into this equation. A low-level VAC charge is passed through the matrix causing it to warm -- but only at sensor-initiated times of both high humidity and sub-freezing temperatures. Typically when it is snowing the sun is not evident in the sky and therefore does not amplify the effect.
 
archited said:
No... that is not the process at all -- the sun and its energy does not fit into this equation. A low-level VAC charge is passed through the matrix causing it to warm -- but only at sensor-initiated times of both high humidity and sub-freezing temperatures. Typically when it is snowing the sun is not evident in the sky and therefore does not amplify the effect.
Click to expand...
then i confess to either not really understanding sublimation or not really understanding your proposal... as far as i do understand it however, sublimation takes more energy than melting so i'm not sure how that will actually be provided and distributed and shielded and sublimation takes place when humidity is low, not when humidity is high.
 
archited said:
That is why I stated that the exhaust would be curbside at the far end of a "boardwalk" some 5 metres away from the nearest building wall and typically adjacent to a planting. I appreciate that it is difficult to visualize without referencing sections and 3-d renderings.
Click to expand...
i'm not sure 5 metres is sufficient to disburse a plume enough such that it would no longer condense on solid objects. i'm also not sure (a) how that plume would be controlled such that it would not hinder visibility for vehicles and pedestrians needing to travel through it or see through it or (b) how you would keep that moisture from condensing - and freezing - within the length of the underground ducts being used to carry it to the end of the boardwalk or (c) how you would limit the amount of hoar frost that would be allowed to condense before it built up to the point of damaging the foliage.
 
Then @kcantor you will just have to wait for the results of our experiments later this year. Certainly under lab conditions the results are clear, but in this case the real proof will be in site condition studies.
 
archited said:
Then @kcantor you will just have to wait for the results of our experiments later this year. Certainly under lab conditions the results are clear, but in this case the real proof will be in site condition studies.
Click to expand...
don't get me wrong, i look forward to your being able to share those results (a) because i am involved in a number of things where it would be really attractive for this to be part of the initial build-out and (b) if this is economical as well as practical - if we do need to separate those things - it would be an interesting component for the city to include as part of its neighborhood revitalization program and projects such as jasper avenue and 103 avenue where it would certainly make the neighborhood or the street that implemented it a more walkable community if it's viable enough days.
 
You must log in or register to post here.

Back
Top