Chill, Toronto

August 17, 2004 4:30 PM

Cool! Toronto's Deep Lake Water Cooling System was launched today. The system cuts electricity consumption in commercial buildings by 75 per cent by drawing near-freezing water through pipes extending five kilometres out into Lake Ontario. According to the city, the system will save enough power to service more than 100 Toronto office towers or 4,200 homes per year, and it will eliminate 40,000 tonnes of carbon dioxide. Here's a public television segment explaining the process. Seems like it makes a nice complement to the lakeshore windmill.
posted by stonerose (48 comments total)

I love Toronto. I wish I had something more insightful to say then that.
posted by chunking express at 4:40 PM on August 17, 2004

What happens to the water after it is done cooling a building off? Do they divert it back into the lake, but at the surface. What about temperature pollution?
posted by mathowie at 4:46 PM on August 17, 2004

The water is put into the filtration system for public use after the cooling part is accomplished - so there's not much in the way of extra water coming out of the lake, nor is there an inordinate amount of temperature addition to the lake.
posted by Dipsomaniac at 4:49 PM on August 17, 2004

mathowie, I should have linked to this diagram. The water ends up in our drinking water system, so it doesn't go directly back into the lake. Another way to think of it is that we're drawing our drinking water from a deeper source, and it multitasks along the way.
posted by stonerose at 4:51 PM on August 17, 2004

The video link says that the conversion of the Royal Bank Office building's ac costs $200,000, comapared to the cost of regular ac equipment, that's amazing!

Good post stonerose, been meaning to check out what the Deep Lake Water Cooling was about.
posted by phyrewerx at 5:00 PM on August 17, 2004

Doesn't it take a lot of energy to get the deep cold water up thru the pipes to the plant, and on thru the buildings? Is the savings on AC greater than that cost?
posted by amberglow at 5:14 PM on August 17, 2004

>and it multitasks along the way
lol.

I've heard about this, but I had also heard rumours it would die off: because the owners of the office towers and condominiums had invested so heavily in traditional air conditioning units, there would be no major takers for the technology. But there seem to be a number, including Steam Whistle Brewery and the Air Canada Centre, meaning Mats is part of the solution, I guess.
posted by philfromhavelock at 5:15 PM on August 17, 2004

amberglow: my knowledge of grade 10 physics tells me that they only really need to expend a lot of energy once the water gets pumped above sea-level, before that the water will seek its own level.
posted by Space Coyote at 5:26 PM on August 17, 2004

I think it's a great idea, and and admirable and impressive initiative,

... but doesn't it sound like the set-up to an environmental thriller movie, you know, the one that ends with "if only we had known that syphoning the lakewater would trigger a new ice age, if only we had known!!!"
posted by milovoo at 5:32 PM on August 17, 2004

amberglow: my knowledge of grade 10 physics tells me

well, smell you, mr. science! ; >

My non-physics-enabled experience of buildings in cities is that they're tall, and for water to cool them would mean pumping of some sort. And my experience of Toronto was that it was flat-ish and spread out, which would also mean that energy is required to get the water from the filtration plant to those buildings, let alone up into those buildings. I really like the idea, but didn't see any indication of what/how much they're expending, energywise, to get the small reward they're getting. I also wonder about safety of water traveling thru conduits/spaces that also hold electric lines/power cables, etc. whether in the buildings themselves or on the way. And it's not like air conditioning is no longer needed in any of those buildings.
posted by amberglow at 5:52 PM on August 17, 2004

oops--nevermind....i just realized the water doesn't go to the buildings. (boy, forget science--i must have slept thru reading too).

I'd still like to see the pumping costs, and the costs of transferring the cooled air.
posted by amberglow at 5:54 PM on August 17, 2004

The diagram I linked to above helps to explain this, amberglow. We're pumping water that we already would have pumped, for drinking and other purposes. But because we pump it from a deeper, colder level, it's also useful as a heat-exchange medium. We don't pump it into the buildings themselves; they have their own, independent cooling fluid circuits, as they always have. The difference is that those circuits are now routed into heat exchangers, where they shed heat to the lake water, that goes on about its business. The costs of transferring the cold air within the buildings are, I assume, similar to what they were before.

Dammit, stop trying to find fault with this! ;-)
posted by stonerose at 6:03 PM on August 17, 2004

The thing I'd wonder about, if this becomes more widespread in the city, will the same thing happen as when the power outages happened last year, where everyone I know said the air suddenly felt much much cooler and less humid / muggy after about a day with no air conditioners running.
posted by Space Coyote at 6:09 PM on August 17, 2004

it's that cooling plant in the middle of the diagram that really confuses me. How does that work? What does it run on? How does it make the cool water colder? And wouldn't this be a better system to use in the subways and underground city network?
posted by amberglow at 6:13 PM on August 17, 2004

If anything, you would need less energy to pump water from deeper in the lake, since the increased water pressure is working with you.
posted by mr_roboto at 6:22 PM on August 17, 2004

Amberglow, it's a huuge heat pump.

They're dumping the heat from the buildings's AC into the drinking water. A buliding has a cooling loop: water comes in at 14.4 C and returns to the chilling system at 4.4 C (from stonerose's diagram).

The heat gets taken away by the minicipal water supply. As a result, water coming out of municipal taps will be 8 to 10 degrees (real, manly Centigrade degrees) warmer than the lake source water. Presumably this doesn't change the sewer temperature.

It still uses electricity to run the pumps, but from their fact page, only a quarter of what would be needed to run a normal AC system for the downtown core. So, even though this won't function in another blackout, it will greatly reduce the drain on the grid.
posted by bonehead at 6:36 PM on August 17, 2004

ok (I guess. As long as the energy cost of doing this is less than the usual cost of cooling. And if it didn't cost the city billions to construct.) I have 17 million more questions about this, but i'll stop. Maybe the next time I go there, i'll take a tour or something.
posted by amberglow at 6:57 PM on August 17, 2004

It's interesting technology. I saw an interview on TV with one of the guys behind it. He explained that it saves energy, but if the price of electricity is capped too low by the government then it's cheaper just to use regular air conditioning.

Incidently, this is one of the coolest summers in Toronto I can remember, I saw some people walking around with coats at night this weekend as the temperature dips to around 50 degrees fahrenheit at night.
posted by bobo123 at 7:08 PM on August 17, 2004

Incidently, this is one of the coolest summers in Toronto I can remember,

It's also the wetest I can remember.
posted by dobbs at 7:37 PM on August 17, 2004

They did something similar at Cornell University and unleashed it last year. The only difference is that the water is put back into the lake because the population of Ithaca is so small. This has caused more enviromental problems than were predicted but I believe that the overall program has been a success. It saves energy and it allows some of Cornell's buildings to finally have air conditioning! The future summer schoolers of Cornell University are going to get a lucky break that I didn't have.

/me shakes cane, yells at kids to get off of lawn
posted by Stynxno at 7:47 PM on August 17, 2004

That is damned cool!

Thank you, I be here all of the week.
posted by fenriq at 7:53 PM on August 17, 2004

Has this worked anywhere else besides Cornell?
posted by gottabefunky at 8:27 PM on August 17, 2004

I wish more of you would should stop being so critical of this project and think of the positive ideals it encompasses. Even if there are minor flaws in the system I can't imagine coal or other common energy sources being better. The fact that it was built is amazing. I realize I good deal of you like playing devil's advocate but come on, this is a really good thing. Give the project, as well as the people of Toronto and Canada at large some credit.
posted by jasenlee at 8:43 PM on August 17, 2004

I always give Canada credit. It's a good idea, if it really cuts enough energy consumption/costs/pollution.

It's just that costs of implementing this were nowhere to be found (unless i missed it), and it's confusing, at least to me. And apparently this only piggybacks on the existing grid, without truly changing anything. Using electricity to try to save electricity seems weird to me. There's wind, solar, hydro--so many ways to harness existing power in the world.

I've often thought that we should put windfarms (and solar panels) on top of every single skyscraper here in manhattan, but unless it'll generate enough power to actually power each building, it's just helping, and not fixing. We're way too electricity-dependent, and there are as of now very limited solutions.
posted by amberglow at 9:00 PM on August 17, 2004

...to actually power each building or to power the entire grid through those means...
posted by amberglow at 9:02 PM on August 17, 2004

The city link in the post says that this will save 35 megawatts when it's at full capacity. That was meaningless to me, so i looked at our energy usage here, at Con Edison: ...11,150 megawatts for New York City and 1,675 megawatts for Westchester County. One megawatt can power approximately 1,000 homes.

Toronto's not a small city--its electricity usage must be near ours.
posted by amberglow at 9:21 PM on August 17, 2004

And interesting thing about those megawatts, is that few though they are, they're prime hours megawatts. At the time when the grid is in the most danger of overloading - when those buildings would otherwise be drawing power for their AC - this system is taking something off the top end.
posted by jacquilynne at 9:29 PM on August 17, 2004

This is a cool idea. I wonder if Santa Monica can suck water from deep in the ocean and cool off the buildings by the beach I wonder if this added heat to the ocean would make any difference?

It seems that this heat would be miniscule compared to the heat generated by San Onfre nuclear power plant.
posted by MaddCutty at 9:52 PM on August 17, 2004

Meanwhile, back at the Deep Water Control Center ...

:cap'n there's something blocking the intake pipe!

:impossible that thing is 12 feet wide, there's no freshwater fish that big.

:I don't know what it is, but it's getting closer.
:Cap'n, you know the crew has all been a bit nervous since
:hearing the old indian legends of the deep lake ...

:shut it soldier, I don't believe those crazy old legends and
:neither should .... aaaarrrrgghghgh!

they never should have awakened ... the CREATURE from the DEEP WATER
--- coming soon to a drive-in near you ---

(I can't help it, there's just something so cinematic about the whole thing)
posted by milovoo at 10:13 PM on August 17, 2004

Chicago, which is becoming quite the green city, has had a variation on this same technology operational for several years. It's generically called district cooling, which is a new wrinkle on longstanding district heating and power which may or may not use innovative technologies such as cogeneration.

In the Chicago case, excess power during off-peak hours is used to make ice [PDF] which then cools several skyscrapers during the day. Theoretically we could use our lake as well. San Diego is another city using these (they're much more common today than this 1990s article could attest). These systems are taking advantage of the regulatory window created by the banning of CFC-based refrigerants, and the consequent major costs in cooling plant replacement.
posted by dhartung at 12:33 AM on August 18, 2004

There have been ideas like this floating around for a few decades now - including Ocean Thermal Energy Conversion. Attempted on a larger scale this technology could be a boon to developing nations close to deep water but there have been concerns with the technology raising the ocean temperature and the ammonia used in the systems causing environmental damage.
Hawaii has in fact been one of the pioneers of OTEC development
posted by longbaugh at 12:53 AM on August 18, 2004

amberglow: Think about it this way.

Air conditioning requires dumping heat somewhere.

Your typical choice of heat-sink is to dump it into the outside atmosphere using big fans and banks of radiators. The problem here is that air does not have much of a carrying capacity for heat. (One reason why we use foams, batting, and goosedown for insulation.) An alternative is to pump water to the top of the building in order to use an evaporative cooling tower. This increases the efficiency a little bit but not by much.

The alternative is to use a better heat sink such as the ground or a nearby source of cool water. Water-to-water heat exchangers are extremely efficient reducing the load on the compressor. Geothermal heat pumps are claimed to be 25-50% more efficient than traditional air conditioning units. 25-50% improvement in efficiency is certainly worth chasing.

In addition to the efficiency gained from using a more efficient heat sink, office buildings gain in another way. With traditional air conditioning somehow you have to get all that heat up to the roof of the building, frequently in the form of hot water. Putting the heat exchanger in the basement rather than on the roof can improve efficiency.

I really like the idea, but didn't see any indication of what/how much they're expending, energywise, to get the small reward they're getting. I also wonder about safety of water traveling thru conduits/spaces that also hold electric lines/power cables, etc. whether in the buildings themselves or on the way.

It is my experience that shared utility conduits appear to be quite common.

ok (I guess. As long as the energy cost of doing this is less than the usual cost of cooling. And if it didn't cost the city billions to construct.)

$128 American according to the Milwaukee Journal Sentinel

And apparently this only piggybacks on the existing grid, without truly changing anything. Using electricity to try to save electricity seems weird to me. There's wind, solar, hydro--so many ways to harness existing power in the world.

Don't you think that both reducing energy consumption and increasing alternative energy sources are necessary and useful? A 25-50% gain in efficiency is nothing to laugh at, and gains in efficiency are needed to make alternative energy sources work.
posted by KirkJobSluder at 1:13 AM on August 18, 2004

I should probably add that the process of pumping water from one place to another is relatively cheap. The real energy dog comes from the compression cycle. Think about how traditional air conditioning works. Traditional air conditioning is like trying to push a stone up a mountain. You are removing energy from warm air and dumping it into hotter air. The only real way to do that is by using a trick of condensation, evaporation and pressure that requires large amounts of energy.

Now if you have a nice heat sink that is cooler than room temperature, all you need to do is push the heat where you want it and let thermodynamics take its course.
posted by KirkJobSluder at 1:38 AM on August 18, 2004

Don't you think that both reducing energy consumption and increasing alternative energy sources are necessary and useful? A 25-50% gain in efficiency is nothing to laugh at, and gains in efficiency are needed to make alternative energy sources work.
I get this more now--thanks Kirk, but gains in efficiency like this may not be enough. I don't think this can be scaled up enough to keep up. Every year demand alone grows by more than the savings expected here in most cities like Toronto and NY, no? We're connected to the same grid, buying and selling to each other when needed (and all blacking out at the same time, as evidenced this time last year), but we all need more and more power every year. And the weather's not going to be better but worse, driving demand up higher and higher for the forseeable future. I think we need bigger ideas and a larger frame of reference. How about giant wind farms in the Atlantic and way up north in the tundra or Arctic or something? Giant solar panels and wind farms in the desert southwest? In late 2001, i was in Spain, and it seemed like every hilltop near Soria (north of Madrid) had those wind things on top--beautiful rows of them following the contours--It seems easier to implement than this exchange thing, and generates power purely from the wind, no? One of the links says that just one of those windmills produces .75 megawatts, which means that only 50 or so of those produce enough electricity to match the savings this pump/exchange thing does--it seems much easier and cheaper. Empty land is the one thing we're not lacking in the US and Canada, and those don't seem to have the potentially deleterious effects as a water pumping thing. sorry for the novel, and so many questions/statements...the anniversary of the blackout put this topic on my mind. I think we need to think much bigger.
posted by amberglow at 6:03 AM on August 18, 2004

The Hawaiian OTEC project that longbaugh mentions conducts research at the National Energy Laboratory of Hawaii, visible from the highway at the shore of the Big Island of Hawaii near Kona International Airport. An interesting side project involves using the cold water to cultivate sea life from other climates and deeper waters, such as lobsters, oysters, abalone, which are sold to local markets. The lab also started selling desalinated bottled water and became financially self-sufficient in 2003. The list of commercial projects is fascinating.
posted by Songdog at 6:24 AM on August 18, 2004

My friend the lakeshore windmill co-op board member wanted a plug for the official site of WindShare, operators of the Lakeshore Windmill.

There.
posted by lowlife at 6:29 AM on August 18, 2004

amberglow, I agree with you that it's a drop in the bucket, but it's an excellent use of an available resource. Wind power or thermal conversion aren't going to eliminate other sources of electricity or cooling for most communities, but if they can reduce dependence on more costly alternatives then clearly it's a good thing.

Every place doesn't have enough wind, or clear skies, or running water to take advantage of these sources of electrical power, and like everything else we do these have an environmental impact. But we still need to make decisions between the environmental impact of a wind farm or a hydroelectric plant and that of a coal or nuclear plant.

In the future I hope that we'll find safe and effective ways of utilizing the incomprehensible solar energy available above the atmosphere for our electrical devices down here. We sure do need to think bigger.
posted by Songdog at 6:31 AM on August 18, 2004

One of the links says that just one of those windmills produces .75 megawatts, which means that only 50 or so of those produce enough electricity to match the savings this pump/exchange thing does--it seems much easier and cheaper.

AmberG. you need to factor in the maintenance issue. Windmills are probably more maintenance intensive because of vibration and metal fatigue. To harness wind power you need strong reliable winds but you also have to design windmills to withstand freak winds (like Charley).

More...
posted by srboisvert at 6:35 AM on August 18, 2004

Hey Miguel, if you are out there, notice how we are NOT really talking about America.
posted by Dantien at 7:06 AM on August 18, 2004

Cool.
posted by DrJohnEvans at 7:08 AM on August 18, 2004

Cornell is lucky in its location, which is really the major reason why this works so well there and hasn't been tried more often elsewhere. The Finger Lakes of central NY are very deep and narrow from glacier carving, and the watertables they are the center of get some of the highest waterfall east of the Rockies. This means that there is constant turn-over of the lake's water, so that the take-out-cold-put-in-hot-water cycle doesn't gradually raise the lake's temperature. It is also, as I can attest, very cold in the winter, which further helps cooling the lake when the system is turned off during the cold months. Finally, the top surface area of the lake is relativly small compared to its depth and volume, so compared to other lakes, less sunlight per unit of water is warming the lake up.

All these factors mean that Cornell and Cayuga Lake are in a perfect situation for utilizing this technology. The process is sustainable because of the unique features of the local geography and meterology, more than any brilliant innovation on Cornell's part. Facilities that need year-round cooling or those that have less than ideal lake sources may not have similar successes, however, and if poorly concieved and designed these systems can have devestating environmental effects.
posted by ChasFile at 7:38 AM on August 18, 2004

It's more than just saving on electricity, you also cut down on the CFCs from air conditioners, and the heat given off by the units as they run constantly. Which I think is a much bigger advantage than the few megawatts savings.
posted by Space Coyote at 7:57 AM on August 18, 2004

For those wondering what this will do to the lake, dig this:

Lake Ontario is big. Big big big. Pulling some cold water off the bottom and returning it slightly warmed up (via the drinking water system, them sewage plants and run-off) isn't going to have an effect on the lake.

Now you might say that after years and years of this, the lake will start to warm up. Well every winter the *top* of the lake gets colder than the cold water that's being pumped out, and I am reliably informed that Lake Ontario does not have stable strata, it churns up every year.
posted by Capn at 8:26 AM on August 18, 2004

amberglow: I don't think this can be scaled up enough to keep up. Every year demand alone grows by more than the savings expected here in most cities like Toronto and NY, no?

I think that if we look for the "one size fits all" solution that we are going to be paralyzed in terms of finding any solution. Of course this probably can't scale up to a solution for an entire urban area. But for already-developed urban cores where it is impractical or infeasible to retrofit "geothermal" heat pump systems, this might be a viable solution.

One of the links says that just one of those windmills produces .75 megawatts, which means that only 50 or so of those produce enough electricity to match the savings this pump/exchange thing does--it seems much easier and cheaper.

Why is this an either/or situation?

One of my life goals is to get off the grid with renewable energy resources. Getting off the grid or fixing the energy problem requires looking at both sides of the supply/demand equation. You get the maximum leverage from solar and wind the more you increase the efficiency of consumption.

I think we need bigger ideas and a larger frame of reference. How about giant wind farms in the Atlantic and way up north in the tundra or Arctic or something? Giant solar panels and wind farms in the desert southwest?

Actually, I think that thinking big might be part of the problem. When you start talking about giant wind farms, then you get into the "not in my backyard" syndrome. Instead, what I think we need are a lot more "drops in the bucket." Decentralized power generation as opposed to centralized power generation. Solutions designed around local communities and energy needs rather than huge big power production projects.
posted by KirkJobSluder at 8:52 AM on August 18, 2004

KJS, you might like this site - it's a blog by the owner/builders of a straw-bale, off-grid house outside of Toronto.
posted by stonerose at 9:16 AM on August 18, 2004

I'm just impressed that it got built at all in Ithaca. When I was a student there ('94-'98), it was the subject of massive debate, wrangling, and protest.

(Granted, a lot of that's due to the demographics of Ithaca (read: lots of ex- and still-hippies) and the not-great town/gown relations between Ithaca and Cornell, but still.)
posted by Vidiot at 9:19 AM on August 18, 2004

I work for a renewable energy co-op in Southern Ontario similar to Windshare (which was linked to earlier in the thread).

KirkJobSluder is right - it isn't really an either or situation, it's very much about diversifying the electricity market along with a strong conservation ethic . Just because we're developing a community owned turbine (which is an ideal local community solution that leads to a more distributed energy system with strong local economic benefits), that doesn't mean we don't or can't support projects like the deep lake cooling project.

All these measures working together help make the electricity system work better and makes our environment healthier. Every little bit that helps maximize efficiency of consumption or reduces our demand gets Ontario that much closer to being able to have distributed renewable energy generation making up a substantial portion of our mix and reducing our need for goal fired generation. All good stuff.

And hey, if Alec Baldwin supports deep lake cooling, maybe I can get Charlize Theron to take a break from saving bears and come cut the ribbon when our turbine starts spinning. :)
posted by Cyrie at 12:37 PM on August 18, 2004

But if yearly growth/added demand exceeds the savings from these small projects, you're still always falling behind, no? If this could be scaled up enough to support the whole city eventually, then i'd be more excited, i guess.

I see the maintenance issue of wind as a good thing--many millions are out of work (at least here in the US) and it could be part of a TVA-type project or something. And as for NIMBY, there are places no one sees (roofs of skyscrapers, way out at sea, etc), and we have millions and millions of acres of government-owned land (in the US) not close to population centers, and this maybe could help save that land from privatization, actually. Canada has even larger stretches of empty land than we do. If we're in a connected grid anyway, why couldn't large things like this be put out of the way? It could also be a savior of family farms (converting them to wind farms), or of once-arable land that's dried up. (I guess i think wind has much more potential than this water/exchange thing.) That solar thing out in space seems incredibly cool, but would cost trillions and trillions.
posted by amberglow at 3:48 PM on August 18, 2004