Cooling Toronto Using Lake Ontario

An anonymous reader writes "Air cooled by the frigid waters deep in Lake Ontario started bringing relief to buildings in downtown Toronto on Tuesday after the valves were symbolically opened on the multi-million-dollar project. The company says that they have the capacity to air condition 100 office buildings or 8,000 homes - the equivalent of 32 million square feet of building space. They note that the cooling system reduces energy usage, freeing up megawatts from the Ontario's electrical grid, minimizes ozone-depleting refrigerants and reduces the amount of carbon dioxide entering the air."

Environmental effects

[jonbryce]

Will this not cause the lake to warm up? What are the envirnmental effects of this? Have they been considered?

I was going to ask about that...

[PedanticSpellingTrol]

but then I had a better question: Can it cool my 64-bit prescott?

Re:I was going to ask about that...

[buro9]

No, to cool a prescott you need to use the water around glaciers.

Re:I was going to ask about that...

[Anonymous Coward]

And if you overclock your city, does it void the warrantee?

Sure it can, but...

[Inominate]

While the cooling of the city of Toronto might have no noticable effect on the lake, your prescott will likely cause the lake to mostly boil off.

Re:Environmental effects

[Rxke]

From the article:

"...Brought to the John St. Pumping Station, the water's cold will be extracted and used to lower the temperature in downtown buildings. The water will then be treated and enter the city's drinking supply...."

So might be a double whammy, the water isn't directly injected into the lake again.

Re:Environmental effects

[mdfst13]

From where were they getting their drinking water previously? My first guess is that this just substitutes water taken from the bottom of the lake for water that would otherwise be taken from the top. Net change in water levels (vs. not doing this) would thus be negligible.

Re:Environmental effects

[MightyYar]

Well, at least in Chicago (on Lake Michigan) they take from the bottom already: See here. [lindahall.org]

Since this has been going on since the 1800's, I think you could probably estimate the environmental impact based on Chicago's experience.

Is Chicago out of luck?

[geoswan]

Your link is interesting. I have one [noaa.gov] too. It took me a minute or two to figure out this page. The map of lake michigan in the lower right hand corner has five lines drawn through it. The five color coded temperature charts each illustrate the temperature at various depths through a slice of the lake. The one closest to Chicago is slice "A", correct?

There was an interview on the morning news yesterday with a guy who is a big fan of this technology. The interviewer asked him if this technology could be used in other cities on the Great Lakes. Yes, he said. There were various cities where it could be used. Rochester and Milwaukee were two examples he offered. But, he said, it could not be used in Chicago. Presumably because Chicago doesn't have easy access to a deep cold layer.

Here in Toronto we have always taken our water from deep in the lake too. As you can see from this map [noaa.gov] the depth drops precipitously just off Toronto Island.

The American fan of this technology was Alec Baldwin, the actor.

The interviewer next asked him if any of those other cities were considering following Toronto's example. He replied that he was flying to Chicago that afternoon to make a presentation.

Re:Environmental effects

[Anonymous Coward]

"the water's cold will be extracted"

Hahahahahaha. Perhaps they can keep these rooms lit by extracting the dark from them.

I tried that

[Rui del-Negro]

I actually got a darkness pump, but it was so noisy I had to buy a silence generator.

RMN
~~~

Re:Environmental effects

[dead sun]

Yes, or we can stop bashing people trying to make technical processes understandable to Joe Schmoe...

Here's a novel idea. How about we educate Joe Schmoe so he doesn't go around thinking completely backwards. If everybody were smart to a certain minimum level our engineers could stop trying to make a technical process understandable by explaining it either (a) incorrectly to the level of being the opposite of what is true, or (b) as though it were magic.

I realize Joe Schmoe would like nothing more than to sit back and watch his TV absorb darkness, but people commonly recognize that it actually emits light. If they can grasp that then they can grasp that the colder water is taking energy from the warmer water with a little effort.

Re:Environmental effects

[JediTrainer]

So might be a double whammy, the water isn't directly injected into the lake again.

I live just north of Toronto, in Markham (part of York Region).

We get our drinking water from Lake Ontario. All of the GTA (Greater Toronto Area), including the City of Toronto, York Region, Durham, Peel etc, use water pumped from the lake.

Our sewage is sent back down to Toronto, where it is treated before being dumped back into the lake. In fact, they're in the middle of building an additional set of sewage pipes to further growth in York Region (sort of controversial, because they're affecting groundwater and the Oak Ridges Moraine while they're doing it. Long story - google for details).

In other words, I don't think it would make any difference, because we've already been drawing our water from there. It's just coming from a different part of the lake.

Re:Environmental effects

[Mysticalfruit]

Doh! It's really early. That "There" should be a "They are" or a "They're".

Re:Environmental effects

[gowen]

No it won't, because the water used to cool the air is the same water that would be extracted anyway, to provide potable water to the city. See this schematic [enwave.com]. Notice the warm water is not returned to Lake Ontario.

Actually, water DOES flow down hill

[Analogy Man]

The scematic does not show the back half of the municipal system (sewer and waste water treatment).

As a grandson of a plumber I can confirm that the water does eventually end up back in the lake. Rule #1 of plumbing ...water flows down hill.

The beauty of this implementation is that the incremental warming of the water may actually further save energy if slightly warmer water comes into water heaters. From a thermodynamic standpoint this looks like a very large geothermal system. The economies of scale may make it quite cost effective too.

Re:Actually, water DOES flow down hill

[gowen]

The scematic does not show the back half of the municipal system (sewer and waste water treatment).

Well, yes, it does. Eventually. But by that time, the heat it gained in the exchangers has long been dissipated, so it's irrelevant. Waste water from this source will be no warmer than the waste water that was previously reaching Lake Ontario.

Re:Environmental effects

[Anonym1ty]

You sound like you have absolutely no concept of just how big the Great Lakes really are.

These lakes are huge. I live on one of them. Calling them lakes is almost misleading. These really are inland fresh water seas. You can't see accross them!

The volume of these lakes is so large you aren't going to have any effect.

Besideds the amount of warm water dumped in by the Coal plant down the way has had little effect other than some very localized warming right by the outlet, This would be nowhere near as much of a temperature gradient even if they just dumped the used water back in. But they aren't They are essentially pre-heating the drinking water they have been getting out of the lake for a hundred years before they use it for drinking. Used water is the same used water that has alwaysed passed through the sewage plant

Re:Environmental effects

[g3rr!t]

From the "Fact Sheet" on Enwave's site,
http://www.enwave.com/enwave/view.asp?/dlw c /fact

Will DLWC warm up Lake Ontario?

* No. Enwave is not extracting from Lake Ontario's water and then directing 'warmer' water back to the lake. The DLWC project has been designed to draw very cold lake water - colder than what the City needs for its water supply - from Lake Ontario. Enwave will extract the extra coldness before the water is sent into the usual water supply system. Water from Lake Ontario is being used

Re:Environmental effects

[drnlm]

Yes, it will. However, you have take relative volumes into account. If the project is pulling more than a very small percentage (and I do mean very small) of the total water out of the lake, you have worse problems than the heat exchange effects (and your population density has exceeded the ability of your local water supply to support it, which leads to a whole lot of additional headaches).

In practice, one will see a small tempretaure increase in the vicinity of the pipelines, but they're probably ecolo

Re:Environmental effects

[Curtman]

This has been covered extensively on Discovery Canada, which I watch regularly. Here's a quote that puts this into perspective:

...He said environmental studies show the system will cause a temperature increase [each year] equivalent to the heat the lake surface absorbs during seven seconds of sunshine....
-Toronto cools off using Lake Ontario waters [greatlakesdirectory.org]

Re:Environmental effects

[ediron2]

There's nothing profound about 4c water at the bottom of a lake. It's just dense. Every winter, northern climates create a whole slew of new 4c molecules that all sprint for the bottom. Once the whole lake is pretty churned up and largely at 4c, then nature goes to work making ice.

Re:Environmental effects

[sporktoast]

No, they aren't heating the lake. They are extracting a small portion of cold water from the lake, and sinking the heat into that water as it flows on its way to the drinking water purification system. The absorbed heat will be dissapated by the time that water returns to the lake through the sewage treatment system.

I'd agree with you that it would be a problem if that isolated part of the lake were being used as a heat sink, but that's just not the case. What IS happening there is that there is a net loss of colder water in that region, at that particular strata of the lake. But the fluid dynamics of water (and the persistence of temperature strata) will tend to disperse the effect over a fairly wide area. The comparison to 7 additional seconds of sunlight over a year is probably about as accurate as you can get without a lot more math.

I'm sure the reversal [chipublib.org] of the Chicago [lindahall.org] River [niu.edu] more than a century ago has affected Lake Michigan more than this will Lake Ontario.

Re:Environmental effects

[VeryProfessional]

We have to recognise that any interaction we have with the environment is going to have some impact on it. This impact will by definition be negative if we characterise any change to the existing equilibrium as being negative. The smart thing to do is to spread the impact by interacting in lots of different ways on a lower level, rather than abusing a single resource, as we currently do with fossil fuels.

I applaud what they are doing in Canada. The more alternative energy sources we use, the better.

Re:Environmental effects

[bhima]

You should join Greenpeace!

I've never seen such a concentration of good looking impressionable young ladies in my life. It's well worth the effort!

Re:Environmental effects

[gowen]

The problem is that after thewind has past through that, it's no longer strong enough to push clouds,

Do you have a source for this. I find it extremely difficult to believe, given the height of clouds, compared to the height of wind turbines...

Re:Environmental effects

[david.given]

Do you have a source for this. I find it extremely difficult to believe, given the height of clouds, compared to the height of wind turbines...

Yes, it sounds totally bogus to me, too. The amount of air that the turbines intersect will be completely insignificant compared to the total amount of air passing through the area. Plus, turbines don't manage to extract any great percentage of the energy out of the air.

Re:Environmental effects

[droyad]

Lets say wind moving at 5 meters/second and a wind turbine (blades) bit of the turbin is 30m, which would make it 60m in total diameter.

So the area of the turbin = 30*30*3.14 = 2800sq m.
so 2800sq m * 5 = 14000 cu m/s (amount of "air" moving through the area covered by the blades.)

1 cu m of air weighs 1.3kg. So 14000 * 1.3 = 18200kg.

18 tonnes of air moves through the area covered by the turbine every second.

Kenetic Energy of 18000kg moving at 5m/s
= 0.5mv^2
= 0.5 * 18200 * 5 *5
= 227500 kg m^2/s
= 227 kilojo

Re:Environmental effects

[Catmeat]

I suspect a little thing called Winter will have an effect.

I'm annoyed by all this hysterical nonsense over environmental effects on the lake. Apart from the fact that the heat input is trivial given the size of the lake (do you know what the heat capacity of 393 cubic miles of water is?) People think the lake is not some finite reservoir of coolness - no, it's a heat store, it cools down in the winter people! Consider the hitorical effect of tens of thouands of summers if that were not true.

In all this ranting, the very real envirnoemental benfits of reducing energy consumption and CO2 emissions get lost in the noise. I'd have expected better from the so-called technically literate.

Re:Environmental effects

[Anonymous Coward]

Water has 4 times the heat capacity of air (4kJ/kg vs. 1kJ/kg).

So 59000 tons of water heated one degree can cool 59000 tons of air 4 degrees.

Furthermore the lake has 27 million times more water than that, so cooling 59000 tons of air 4 degrees would warm the lake (average temp) 0.00000004 degrees.

Re:Environmental effects

[mpe]

Will this not cause the lake to warm up?

Very slightly if the water is fed back into the lake. However water has a high specific heat capacity around 4.2kJ is required to raise one litre of water by 1 degree celsius. The water in this case is comming from a very large lake, so it would take a huge amount of energy input to change the temperature of the lake by any noticable amount.
There also exist methods of extracting heat from rivers and lakes for heating. So possibly these could be used in winter.

What are the envirnmental effects of this?

Most likely considerably less than dumping heat in to the atmosphere, which is how conventional air conditioning works.

Re:Environmental effects

[Junior J. Junior III]

What do you know, now we ARE paying to heat the outside. My dad will flip his wig when he hears about this.

Re:Environmental effects

[jonbryce]

If you take cold water from the bottom, then surely it will be replaced with warmer water from above. Is there anything that makes the water cool down once it is in the lake?

Re:Environmental effects

[black mariah]

The water at the bottom of the lake isn't special. The only reason it's cold is because it's so far away from the surface that it can't be heated by the sun, and the water on top helps wick away any heat that might build up. Go dive into a lake. The first few inches of the surface might be warm, but down as little as five feet you're looking at a significant drop in temperature, and it just gets colder as it goes down.

Re:Environmental effects

[jonbryce]

Also because cold water is denser and so it falls to the bottom.

When the pre-heated warmer water from nearer the surface falls down to replace the cold water that is removed, what happens? Does it say warmer, or does it cool down?

Re:Environmental effects

[black mariah]

It cools. How do you think the water got cold to begin with?

Re:Environmental effects

[L0C0loco]

What??? Water is its densest at a temperature of 4C. Cold water pumped out during the summer cooling months has a chance to be replenished during the next winter. As the winter ice melts and the melt water warms it begins to sink due to the relative increase in density as it approaches a temperature of 4C. So long as the winter cooling capacity of the lake exceeds the summer cooling needs of the city, this should be a sustainable practice. It is true that the thickness of the cold layer will thin during the summer pumping season, but it will thicken again during winter. Obviously, this pumping will cause the mean thickness to decrease - they just need to hope it doesn't thin too much. The problem with free lunches is that people eat too much, get fat, and die!

Re:Environmental effects

[macthulhu]

I live about 90 miles south of the Canadian border in Western NY... The winter cooling capacity 'round these parts is pretty high. It's about time somebody figured out a way to use the area's largest natural resource... Snow. My only question is what happens to algae growth if the lake warms up even a couple of degrees?

Re:Environmental effects

[alienw]

Warming up a lake a few degrees would take a ridiculous amount of energy, more than any city could possibly put into a lake. Calculate it, it takes 4.184 joules to warm up one gram of water one degree C. There are 1640 km^3 of water in Lake Ontario. That's 1 640 000 000 000 cubic meters, which is 1.64 × 10^18 grams. 1.64e18 * 1.0 deg C * 4.184 J/g-degC = 6.87e18 J. This is 1906044444444 kilowatt-hours, which is a hell of a lot.

Re:Environmental effects

[k12linux]

Based on the info I could find online Lake Ontario contains just over 1.6 trillion(US) metric tons of water or almost 3.6 quadrillion(US) pounds. One BTU is required to heat 1 pound of water 1 degree (F).

According to a cooling calculator online, a 30x60 office building would require approx 23.5 million BTU cooling over the course of a month. This assumes the building is insulated (I'm sure all Toronto buildings are) and that it's longest wall faces the sun. It also assumes cooling 24 hours a day. (If somone out there is a cooling systems engineer or contractor, why not share the actual cooling needs for typical office builings?)

Based on the numbers (and assuming the cooling plant is fairly efficient) then you should be able to cool somewhere around 51 million such buildings for three months (about the max cooling season there) before you have transfered enough heat to raise the lake's temperature one degree. I suspect if you used accurate heat transfer numbers you'd find it would take even more time.

In other words, before you could make any significant difference in the lake temperature, the next winter should re-cool the water already as others have mentioned.

Re:Environmental effects

[mwood]

Ya know, if the only problem with putting heat into the lake is that winter doesn't take it out fast enough, they could do what I do in my home, with a closed-loop groundwater heat pump: take the heat back out in the winter to *warm* the buildings.

Re:Environmental effects

[pilgrim23]

200 yers ago men with horse buckboards and hacksaws went out on the lake, cut up massive blocks of ice, hauled these back to underground brick lined cellars and packed them in straw. All summer this ice was used to cool those who could afford it. This pumping tech just strikes me as an extension of the earlier tech.

Re:Environmental effects

[LWATCDR]

The amount of extra energy this will put in to the lake should be close to zero. The water is going to be used as drinking water once they dump a little heat into it. If they where taking that water from the lake to drink anyway the total change from right now should be zero.

Re:Convection?

[Emperor Igor]

This is the ying and the yang of every decision. There is a side effect to everything.

The question is whether this kind of pollution is better than the carbon dioxide/refrigerant chemicals/coal power plant pollution. It is likely the answer is "yes".

Re:Convection?

[berzerke]

...The question is whether this kind of pollution is better than the carbon dioxide/refrigerant chemicals/coal power plant pollution. It is likely the answer is "yes".

As with any change, there will be winner and losers. In this case, I think the extra heat could make far more winners than losers.

I used to work at a coal fired power plant, the outflow channel (where we dumped warm (but clean!) water) was a haven for fish. Everytime I went past the channel outside the plant, there were always people fishing. Employees could fish closer to the outlet and they would. I watched them and most didn't even bother baiting the hook there were so many fish! Large fish for that area of the bay.

Also an interesting fact about water

[ShadowRage]

and the water will never reach freezing at the bottom, it'll always be a degree or just afew hundreths of a degree above freezing at the least, never lower than that? why? water in its solid form is lighter than its liquid form, it's one of the few elements that does this, which makes its liquid form rare in the universe. However, by utilizing this, they can cool office buildings and never worry about heating up the lake, unless they pumped the warmer water they used to the very bottom, but even then the water would chill, and would get colder again, because the amount of cold water outweighs the warm water.

hell, if you wanna see a good example, look at the bottom of the ocean where there is no sun, but there are volcanic vents, the water at the bottom of the ocean isnt hot due to that, and that's more constant heat output than any city could produce in a million years.

Re:Also an interesting fact about water

[ShadowRage]

oh and ignore some of the stupid errors I made.. I'm just waking up.

where I said elements I meant liquids

and the reason the water wont get warm is that the warm water will rise above the cold water, and when it cools it'll sink.

water's interesting in what it does.

Re:Also an interesting fact about water

[mwood]

You meant "compounds".

You also meant 4 degrees C, not a few hundredths. Below that point, the molecules are slow enough for hydrogen bonding to begin dominating their interaction, and the structures that form take up more space than the unstructured liquid, meaning it's less dense, meaning it will rise above the denser water which is (at this temperature) slightly warmer.

If you notice, you also meant "less dense", not "lighter". H2O has the same mass/mole at any temperature (and the same weight too given equal gravitational acceleration).

Water is, indeed, interesting. Let us know when you're fully awake.

Re:Environmental effects

[SillyNickName4me]

While what you say is true, it in no way changes that the temperature at low levels will rise as a consequence. Explaining how the water gets that cold says absolutely nothign about what happens when you remove it, it only suggests that if you leave it alone long enough, the water at low levels will have cooled down again.

What damage it causes inbetween I do not know, but I do know that it has to be looked at. We have made too many mistakes assuming such things were harmless.

Re:Environmental effects

[black mariah]

Something you have to keep in mind is that we're talking about a lake with nearly 400 cubic MILES of water in it. It would take a *LONG* time of pumping millions of gallons per hour (Ontario holds about 430 TRILLION gallons) to even dent the lake, and that's assuming you can somehow stop all water from flowing into it before you start.

Re:Environmental effects

[mwood]

In sufficiently large bodies of water there's this thing called the thermocline, separating surface circulation from deeper circulation. It's somewhat like two different bodies of water stacked one on top of the other -- there's less mixing between the two than one would naively expect.

Taking deep water, warming it, and returning it disturbs the system, and it would be prudent to understand the effects of that disturbance. If the city's already doing that for drinking and washing, well, now they are doing a whole lot more of it and the effects will be more pronounced, so again it's prudent to understand the effect of increasing the pressure on the system's equilibrium.

I don't study large lakes and I don't know what significant effects, if any, might be expected. I just hope that someone *does* study this particular lake and *does* understand the issues and *was* consulted.

I do hope it works out well. It's a nifty idea.

Finally, this ignorant Yank must admit that his first thought was, "Toronto needs *cooling*?" :-)

Re:Environmental effects

[uberdave]

We have to keep our igloos from melting during the blistering summer heat somehow.

Re:Environmental effects

[MemoryAid]

I don't study large lakes either, but I did take a few minutes to run some numbers. Based on somebody's claim of 430 trillion gallons of water in Lake Ontario (and I assumed US gallons, as that is the most common gallon still in use), I came up with 216700 megawatts required to raise the average temperature of the lake one Kelvin in one year.

I assumed standard water (1 kg/L) when converting from volume to mass. I also used only two significant digits for specific heat capacity (4.2 kJ/KgK). I also assumed uniform temperature and uniform heat distribution because I'm looking for averages, to get an idea of order of magnitude.

Anyway, I RTFA and saw that the cooling power is only about 207 megawatts. That convinced me to rule out any macroscopic environmental consequences and get on with my life.

Mod parent down - untrue

[dschl]

Read this post [slashdot.org]. Lake Ontario (like most lakes in Canada) mixes once a year in the autumn (turnover, or overturn - I've heard both terms used), usually in the late fall prior to freezeup. The lake is only stratified in the summer, and the only special property held by water at the bottom is a lower temperature in the summer.

Re:Mod parent down - untrue

[Nept]

I know I'll get modded down for this, but I just had to reply to your sig.

Re:Environmental effects

[djdavetrouble]

RTFA! They don't take the water at all. They only take the coldness.

and when they take the coldness the water then goes into the city's potable water system. RTFA!

Re:Environmental effects

[Tuzanor]

Actually, Greenpeace is completely backing this endeavor. The water they're taking was also part of an overall plan to upgrade the drinking water plants, so the water is just being diverted before going into the drinking water. Then the water just returns through where the water has always been going (sewers, water treatment, and then probably the lake).

Re:Environmental effects

[black mariah]

the 'bottom layer' of 4 deg C water will get thinner, as the water that's pumped out is replaced with surface water that has a higher temperature

But how long will it take that layer to be eroded? Also, it isn't replaced by surface water. The water directly around it takes its spot. We're still talking about water that's 83 meters below the surface.

Maybe the cooling capacity of the lake bottom is high enough to counteract this, though.

Precisely. It would take a *LOT* of pumping to get that much water o

Re:Environmental effects

[vidarh]

You're assuming a closed system. Since when did a lake become a closed system? As many others have pointed out: Consider colder seasons, rain, cold water entering from rivers etc. Now, look at the other side: Consider the consistent heat added by sunlight and warm air over the entire surfae of the lake. Want to bet that this project is going to be lost in statistical noise if measuring the total energy input and output of Lake Ontario?

Re:More environmental effects

[YrWrstNtmr]

A warmer lake will lead to more lake effect snows in ... Cleveland.

Wrong lake. Cleveland is on Lake Erie. Perhaps you're thinking of Rochester.

Re:Environmental effects

[An dochasac]

Forgot the link, and me login: Toronto's solution will have far less impact than Milwaukee's solution of building more coal power plants [greatlakesdirectory.org] which will suck 2.2 billion gallons of water and fish from Lake Michigan every day and convert it to mercury contaminated steam, or discharge it at a much higher temperature... all in order to inefficiently cool buildings to the temperature of lake michigan, a stone's throw away from the power plant. Can I burn some karma points with a duh here? Canadian industry finally cops onto an idea that every 7-year-old has when his toes are in 40F degree water and his head in 100F air. If only American industry wern't so hung up on our industrial past, we could see the way to the future.

Nice :)

[Killjoy_NL]

This is the kind of stuff I like to see :)

Ok, it costs a lot of money, but in the long run it has the possibility to save so much more than money: the enviroment.

You have never been to Niagara Falls, have you?

[geoswan]

but in the long run the lake will evapourate, making the climate in the region less stable (water holding a lot of heat is one of the main reasons the earth has such a (relatively) mild climate) with hotter summers and colder winters, leading to the requirement of more heating in winter and more air conditioning in summer... brilliant

Lake Erie and Lake Ontario have about the same surface area. But Lake Ontario is much deeper and so has a greater volume. I have links here to charts showing the temperatures, at various depths across various slices of Lake Erie [noaa.gov] and Lake Ontario [noaa.gov].

Note that Lake Erie is much warmer. But most of the water in Lake Ontario came from Lake Erie? Why is it so much colder? It cools off in the winter time. It takes water from the Niagara River six years before it flows down the St Lawrence.

If, for the sake of argument, Rochester, Kingston, Hamilton all used deep lake cooling, and they all grew so much that they exhausted the Lake's deep layer, Lake Ontario would still not evaporate, any more than Lake Erie evaporates away to nothing.

Yes, there are deep areas of Lake Ontario that have been at 4 degrees celsius for a long time. How long? Since the last ice age? The glaciers covered the entire Great Lake basin a few tens of thousands of years ago. So that is how long a unique deep lake water ecosystem would have had to evolve.

How much water would the cities have to draw from the deep layer to use up all the cold layer? I don't think you understand how deep the Lake is, and how great its volume. Look at these three maps. West [noaa.gov] Centre [noaa.gov] East [noaa.gov]. So, lets say the deep layer is currently something like half to one third of the volume of the lake. The cities would have to use up the equivalent of the flow of two or three niagaras worth of water in order to drain all the deep cold water.

So long as our winters continue to get cold enough for the lake to cool to 4 degrees the cold layer gets regenerated every winter.

I think it could be argued, if Global warming every gets bad enough that using deep lake cooling exhausts the cold layer in mid-summer that, since we have the infrastructure in place, we use it every summer until it is exhausted. What about the cold deep lake water ecosystem? I am all for preserving interesting, unique ecosystems. But I doubt that a few tens of thousands of years is long enough for it to become interesting and unique.

Just two questions

[cyclop]

(1). What will happen when the lake water will be warmed up? Ok,it will perhaps take a long time,but...

(2). How does the energy required for pumping / distributing the water and maintaining pipelines and machinery compares with electrical conditioneers?

Said that, it looks like a nice idea.

Re:Just two questions

[jonbryce]

Q1 is a valid concern.

Q2 is apparently answered in the article. Approx 25% of the energy requirements for electrical air con.

Re:Just two questions

[ediron2]

Man, I can't believe I'm getting sucked into this moronic, paranoiac debate.

1 - Lake Ontario doesn't freeze over, but it does have some surface ice in midwinter. Ice implies a surface temp at or below 0 degrees c. Right?

2 - Having lived next to another sizeable lake (Lake Champlain, which typically does freeze over), and as an EXPERT in hydrodynamic modelling, I can assure you that that niggling little physics detail about water having maximum density at... (drum roll) 4 degrees C is accurate. However, twice a year, lakes like Ontario have all their water churned about as ambient average temp falls below 4 degrees C, then as ambient temp rises above 4 c. Wierd, but true. Frankly, seiche's are wierder [wisc.edu].

3 - So, as winter gets cold enough, any water not AT 4 degrees C rolls to the surface, where it is... say it with me... chilled by the Toronto winters. Before any ice is made, everything in the lake chills to 4 degrees C (this is my biggest oversimplification here, since inversion layers can exist in large water bodies. It doesn't matter in the overall calcs to follow, since all I was interested in showing is the mechanics for recharge of the cold zone).

4 - The thermal mass of Lake Ontario (one site says 86 m average depth, x 19,000 km^2 in area... 19,000,000,000 x 86 x 100 ^3 cm^3 per meter x 1 degree c x 0.0039683 btu's per calorie x .000000293 btu's per megawatt hour = 2* 10 ^9th Megawatt hours needed.

The Fact Sheet on Enwave's site [enwave.com] says they're gonna free up 59 megawatts. Now, I should be able to disregard a part of this as an efficiency improvement (electricity for cooling is gawdawfully inefficient, compared to non-compressive heat exchangers like this'll use), but I'll eat the inefficiency because that's the nice guy I am. 59 x 24 x 365 (megawatt-years to megawatt-hours) gets us *finally* to matching units. If I haven't completely bolluxed the calculation, we're looking at a capability of handling 3673 of these facilities. Or, the temp of Lake O going up 1/3673 of a degree.

Oh. Yay. The little fishies aren't even going to notice this. In fact, there's room for exporting this capability and if we're willing to warm Lake O by a few degrees I think it'd take care of the AC demands of most of North America, if them clever Canadians can just figure out a way to export this.

When she's working hard, the sun 'wastes' enough energy warming up dirt and water around the world to fuel our needs a thousandfold over. When she's not paying attention (at the poles, nights and winters), earth's radiating it off like gangbusters.

The risk of us boogering up our surroundings when we do BIG things is a valid one. But not here, not yet.

We've reached the point where we're influencing the world in several spots: cfc's, pesticides, acid rain, particulate emissions, garbage, animal populations, etc. etc. etc.

But this isn't one of them. As a side joke, I bet there are a few million Toronto residents that'd be more than happy to let the thermal average temp of Lake O go up 30 degrees, just for the lake-effect warmth it'd impart on their town each winter and the ability to swim without turning blue in midsummer. Back during a nasty winter ('93), a favorite bumper sticker of mine was 'Another Vermonter *for* global warming'.

Rock on Toronto & Enwave.com

Re:Just two questions

[Yaztromo]

Man, I can't believe I'm getting sucked into this moronic, paranoiac debate.

You and me both :P.

Just to amplify your already excellent response, the other thing people here are forgetting is that Lake Ontario isn't a closed hydrolic system. It is fed by hundreds of rivers which dump tons of sun-warmed water into the lake in summer, and which dump tons of frozen and near-freezing water into it during the winter and spring thaws.

This input vastly outnumbers the amount of cold water the Enwave system will be extracting, along with vastly outnumbering the amount of warm water input to the lake.

In the end, the lake will be the same as it's always been, and less air-polluting fossil fuels will be required to run the existing air conditioning systems. Looks like a win-win situation to me.

Yaz.

In a related story...

[hazman]

Halliburton, Bechtel and General Electric have signed a multi-billion dollar deal to refrigerate the waters of Lake Ontario.

The temperature of the lake has inexplicably begun to rise. Algae blooms, moss growing on surronding trees and Corona beer bottles scattered on the shore have alarmed the Canadian Department of the Interior to take swift, albeit expensive action the save the ecosystem of the lake.

Messing with lakes: NOT a good idea

[Capt'n Hector]

Several times in recorded history, lakes have "belched" massive amounts of carbon dioxide, killing off not only fish, but people in surrounding areas. Lake Nyos [bris.ac.uk] is one such example. The circumstances vary, but always involve extremely deep water, saturated with CO2, being shifted to a shallower depth. When this happens, water has a much lower capacity for CO2, and it is released into the air.

Not that I'm predicting this will happen here, but it's usually best not to heat deep water like that.

Re:Messing with lakes: NOT a good idea

[Anonymous Coward]

I think this is unlikely to be a problem.

Lakes 'turn over' like this when there has been long-term stratification of the water. Stratification occurs when a layer of warm, less dense, water forms over the colder, denser, lower layers. This is stable since the heat of the sun reinforces the stratification. Only a seasonal reduction in sunlight, or strong winds, can mix the layers.

Lake Nyos is in a tropical area where there is a permanent, marked stratication due to year-round abundant sunlight. Since mixing of layers is so rare, hug amounts of gas can accumulate in lower layers. This is dangerous should something trigger a rapid breakdown of the stratification - such as the landslide in Nyos.

In temperate areas stratification is confined to the summer, only then is there sufficient sunlight. In other seasons stratification breaks down and mixing occurs such that a potentially dangerous build up of gas is not possible.

Re:Messing with lakes: NOT a good idea

[No Such Agency]

They're not sending the warmed (by 8'C) water directly back - it goes to drinking water supply. The CO2 thing IS super-scary though, imagine living by a lake like that (which people still do) :-O

The answer is in the article.

[bit4byte]

According to the site they use the city water supply
that feeds from the bottom of the lake to cool down
a closed loop system, which is then used to cool down the offices/homes. No warm water is fed back into the lake. So the lake should not heat up at all.

The lake is NOT warming up !

[arska]

RTFA !
Look at the diagram on http://www.enwave.com/enwave/dlwc/ They warm up the city's drinking water by a few degrees.

A

Re:The lake is NOT warming up !

[frovingslosh]

Actually, it's unlikely that the city was drawing it's drinking water from this deep before. They were almost certainly taking it from a point higher up and warmer. So the city drinking water may not be warmer at all as a result of this; it might even be cooler. And, since the lower water can hold more CO2, it might be slightly carbonated! (Look for the interesting side effects when somewhat more acidic carbonated water is flowing through old pipes.)

On the other hand, since the cold water is being taken from the lake now rather than warmer water, the thermal barrier between the warmer top water and the lower cold water may slowly lower (and it is a very sharp layer, not the gradual drop in temperature you might expect). This may indeed have some effect, but that doesn't seem very likely.

They could have gone the simpler and more direct route of just building a power plant that used the difference in tempersture between the cold bottom water and the top water to pump up that water and generate electricity. Such plants have been proven to work with ocean water, and should be even simpler in an environment without salt water's effects. I'm assuming they didn't because in Toranto that top water would also get pretty cold in the winter. Still, I don't expect they will need much air conditioning in the winter anyway, so a seasonal power plant might have been as good or better of an idea.

Re:The lake is NOT warming up !

[mcdade]

They are not "warming up the city drinking water", they are using the warmer water for city usage, which is different.

Anyone who lives around Lake Ontario knows how freaking cold that lake is, even when it's high 90's out, humid as hell, you can turn on your cold water and get freezing water out all summer, it's because this is a large deep lake. I live in a different city (still on the great lakes) yet the cold water is noticable warmer in the summer months due to the lake that it draws from being so sha

The London Underground is also doing this

[carndearg]

The London Underground is doing this as well, though they are doing it with the ground water they pump out of the tunnels. If it relieves the sweaty hell of a crowded Tube train it gets my vote!

Here's the BBC's story about it [bbc.co.uk].

And more importantly, Alec Baldwin was there

[starvingartist12]

The Toronto Star's coverage [thestar.com] has more info about Alec Baldwin's participation in the launch of the Deep Lake Water Cooling system:

Hollywood heavyweight Alec Baldwin heaped praise on Canada's "forward-thinking" approach to energy today at the launch of a new system that uses the frigid waters of Lake Ontario to cool downtown office buildings.

The system is nothing short of a "miracle," gushed Baldwin, 46, the square-jawed star of blockbuster films like The Hunt for Red October and Ghosts of Mississippi who moonlights as an environmental activist.

"This is an important signal you are sending not only to your fellow countrymen but to the world," Baldwin told the gathered crowd.

"There's no project on a municipal level this size that's been attempted or has been executed before like this."

Unconventional thinking seemed to be at the heart of today's event, which looked like a Hollywood premiere, complete with a blasting techno soundtrack, fog machine, and bizarre floor show of twirling gymnasts contorting themselves around a large ring suspended from the ceiling.

"The cold is extracted"?

[Bertie]

Er, how? What does this mean? Cold's just the absence of heat, the only way to "extract" it is to heat something up.

This is what renewables are about

[T.Hobbes]

For me, at least, this is what renewables should be about: finding a local source of economical renewable energy, and applying the appropriate technology to make it useful. The key thing, though, is that the methods change depending on what's availible locally.

Natural Laws.

[MrKane]

John St. Pumping Station has obviously found some way of overcoming The Second Law of Thermodynamics as:
'the water's cold will be extracted and used to lower the temperature in downtown buildings'.

Unit for Cold anyone?

Re:Natural Laws.

[Avian visitor]

Unit for Cold anyone?

The theory of cold is just a part of thermodynamic theory of darkness [ox.ac.uk] .

The unit for cold is derived from unit for darkness and equals D.s, where D is unit for darkness and s is second.

Another link

[Kernel Kurtz]

From the CBC

No registration required;

http://www.cbc.ca/story/canada/national/2004/08/ 17 /enwave_040817.html

Do building ACs use refrigerants?

[Shivetya]

I thought they were strictly water/evaporation based when it came to large scale building cooling? Hence I don't see the claim of reducing refrigerants. Now where are they determining reduction of CO2 into the air? Is this from the power savings?

I know that "real" portable cooling units have no refrigerants (the corp I work for resells some).

I can see the savings from power, but I still don't like the idea of sucking cold water from the bottom of a lake. It would seem to me you could upset the balance and possibly cause the lake to flip thereby releasing tons on CO2 - something which happened in Africa, which did kill a lot of people.

Show me the numbers

[Stephen Samuel]

This is one of those things that looks good when you start -- but what happens when everybody starts doing it? What I'd love to see is some info on the volume of water extracted from the lake for this project vs. the volume of water in the lake. This would give geeks like me a much better chance of being able to figure out for ourselves just how much this is going to affect Lake Ontario and how much the basic idea is going to affect the lake as the idea becomes more popular (as I expect it will).

It's a GREAT Lake

[Titusdot Groan]

Just a reminder folks, Lake Ontario is one of the Great Lakes, it's REALLY big. Like you can't see the other side of it from the shore line. Big. Really big. Like it's huge. Average depth of 86 meters, surface area of almost 19000 km2. Big.

Did I mention it's big?

Plus water turns over automatically at 4C (that's the temperature when water is it's coldest). Lake Ontario is not meromictic and has a natural turnover anyways.

Re:It's a GREAT Lake

[lastninja]

(liquid)Water is at it`s coldest just before it turns into ice. It might have its highest density at 4C though.

This has been around for a long time

[JBMcB]

Geothermal has been around for a long time. There are closed loop systems that put the condenser coil underground, and open-loop systems that use streams (ideal) and ponds (somewhat less ideal)

The General Motors Technical Center in Warren, MI has been using open-loop cooling for decades, using the large pond on the campus as an open-ended evaporator. The fishes that live in it don't seem to mind.

There's a nice picture here:
http://www.bcausa.com/projects/tax_gm.html
(Pictured is the "Design Dome" the design building to the right, general engineering in the buildings above the pond, and the Cadillac, Chevrolet, Pontiac and mid-lux buildings beyond)

This is happening elsewhere

[samjaffe]

Cornell University recently did this with the deep water of Cayuga Lake (http://www.worldchanging.com/archives/000839.html ). As you can imagine, it caused quite a spirited debate in such a liberal town as Ithaca. In the end it was approved and the University is gauging the environmental effects very carefully(http://www.town.ithaca.ny.us/PEZ%20proje cts/Lake%20Source%20Cooling/lake_source_cooling_mo nitoring_p.htm). So far, there's been little effect. Although some (http://www.cldf.org/tt_981216/chap1.html) might disagree. I would like to point out to the concept's cheerleaders that there's nothing wrong with asking questions about the fundamental ecological effects of our engineering projects. Those questions should be answered thoroughly and carefully. Yes, global warming appears to be a severe problem, however let's not replace it with a bigger problem by stifling debate and rushing in with an ABCO2 (Anything But Carbon diOxide) attitude that might be more harmful than the disease.

I hate this

[nightsweat]

I don't hate that the Canadians are doing this sort of work, but I do hate that we're not. Look, I'm in Chicago, a huge American city with the slogan "the city that works" and where we decided that the river flowed the wrong way, so we changed it. Why the hell aren't we putting in something like this?

These days those quasi-socialists have it all over us...

Similar implementation

[PrebleNY]

A similar lake source cooling project was implemented at Cornell while I was there. They tore up half the campus laying 36" pipe down to the nearby lake. Of course this project is much larger (with a larger lake as well), but from what I have heard the Cornell project has been a success despite the hand wringing of the radical environmentalist. The Toronto plan seems to be even better as they are not discharging the water directly back to the lake (as they do in Ithaca) but are processing it for drinking water. more information on the Cornell LSC website http://www.utilities.cornell.edu/LSC/default.htm

Geothermal Heat Pump

[InterGuru]

For those of us who do not live near a body of water, you can get considerable savings from a Ground Source (Geothermal) Heat Pump. This system uses an air conditioner/heat pump which uses ground water as a heat sink in the summer and a heat source in the winter. Because ground water is a steady temperature ( usually 50-60 degrees F) you get an energy saveing of 20-40% over conventional systems which use the air as a heat source and sink. The air is hot in the summer and cold in the winter, which is exactly what you don't want.

You can find more infomation here [anl.gov] and here [southerncompany.com]

As a pedestrian I welcome this

[geoswan]

There is one advantage of this system that I haven't seen mentioned yet.

Have you ever had an errand in the downtown office area, and walked through a big blast of hot air?

Not only does this save energy. But because those downtown buildings are not using conventional air conditioners for cooling, they are not dumping megawatts of waste heat into the outside air. I read that the use of this technique should reduce the local ambient air temperature on the downtown streets, where it is used, by several degrees.

As a pedestrian I welcome this.

Re:As a pedestrian I welcome this

[WindBourne]

Interestingly enough, most large buildings do run AC during the winter. Add up all the heat from ppl, computers, lights, etc. and the fact that buildings are better insulated than 50 years ago, you will see that you have to pump heat out (at least during the day). Bizarre though, huh.

In fact, Denver International Airport was ripped for choosing to do a white cloth roof. But once it got out that DIA would be running A.C. 24x7, then it became apparent that the roof lowered the heating costs. I first became aware of the need for a.c. in large buildings when the sears tower and O'hare were running a.c. while the outside temp. was -40F/-40C.

Residential applications?

[swb]

I've always wondered why you couldn't use a similar system in a residential area. We have a lake behind our house that's about a mile around and about 8 feet deep on average; couldn't we (at least the immediate lakeshore residents, if not a larger amount of neighbors) use the lake water to augment our air conditioners?

You'd dump warm water back in, but this could be augmented somewhat by holding tanks and underground piping that cooled it back to ground temperature. If the lake was man-made, the environmental effect would be essentially nil, and you'd only have to worry about thermal calculations.

This might not make sense for retrofitting, but what about for new developments? People like lake/park areas, and there's no reason that a cooling pond couldn't be framed in a naturalistic setting.

I suppose it all comes back to commercial viability; it'd take a more expensive air conditioner capable of combining water cooling with electrical compressor cooling, the "community" would be responsible for the cooling pond and piping, and the electrical savings might not matter.

Re:Residential applications?

[rebelcool]

the capital investment tends to be prohibitive for residential applications.

Like its much more energy efficient to use chilled water a/c with a large central cooling tower. Then pump chilled water out to each home for use in chilled water a/c units. Large office and university campuses do this. But, at several million dollars, the investment is just too much for developers.

Re:The lake WILL warm up

[pla]

We've done enough (I'm from Toronto) to screw up the environment around this city, we should NOT be doing this!

Did no one RTFA???

You've already extracted from the exact same source of water for decades, for use as drinking water. This just raises the temperature of your drinking water by about 10C, with a net "gain" derived from reducing AC costs to the city.


So yes, you can technically say that removing water from the coldest part of the lake raises the average temperature. But to turn that into "we should not be doing this" ignores the reality of the situation. This results in less energy consumption overall, a good result no matter how you look at the situation.

Re:The lake WILL warm up

[MKalus]

So you think removing the cold water (and last I checked we still have Winters in Toronto so it will cool down again) will be more damaging than pumping all the CO2 into the air by trying to cool conventionally?

Re:The lake WILL warm up

[mbourgon]

No, the point is that environmentalists don't want alternative fuels or alternative practices. They want less technology. Less tech = less electric used. I'll probably get modded as troll or funny, but I'm serious. Wind energy is touted - until someone wants to use it (New England wind-farm fight).

What's the alternative here? Apparently there is none, so we better just not cool those homes.

I recommend you take a much needed chill pill

[FreeUser]

Even if they are not putting the warmed water back into the lake, the removal of cold water will raise the average temperature of the water (as warmer surface water has more of an impact on the overall lake) and will cause the lake to get warmer. We've done enough (I'm from Toronto) to screw up the environment around this city, we should NOT be doing this!

Yeah, the equivelent of eight extra seconds of sunlight hitting the lake will be death to the entire eco-system! Run away, run away! Burn freighters full of fuel and oil instead! (RTFA if you don't get the reference)

Get a grip. YOU have a much bigger impact on the eco-system every day you use heat, airconditioning, refridgeration, eat, sleep, shit, work or play.

The hydrocarbins the manufacture and use of the computer you typed your comments on probably have a larger impact on global warming than this entire project. The Canadian's approach is the smartest solution to this problem that anyone has come up with in a long time. Is it scalable to every city on the coast of that lake? No (8 seconds of sunlight is one thing, eight days equivelent would be another), but that doesn't mean we shouldn't be doing it in order to reduce the consumption of power in other areas.

Nothing is a panacea, but this is a damn sound solution for Toronto, and they get to do it by being there first. Any overall solution to our energy, global warming, etc. problems will involve numerous clever solutions, and this project stands a good chance of being a part of that solution.

And as for impacting the environment: 6 billion people breathing the air impact the environment. If you truly don't want to have an impact, slit your wrists. Oops, your decaying flesh will still have an impact, so you're out of luck there too. Better get used to it, because people do have an effect, and they always will. The impact of this project is benign and minimal, compared to every other public works project out there, including the sewage system in your town you probably make use of multiple times every day.

Re:5 Tonnes CO2 per Car?!

[the_twisted_pair]

Run the numbers for burning gasoline and you'll find out.

1 Imperial gallon of petrol ~8lbs. Stoichiometric combustion requires 14.7:1 air:fuel ratio by mass, so burning that gallon in travel requires about 118lbs of air. Estimate about how much fuel you burn in a year, multiply by 118 (or 95 for US gallons) - and suddenly five tonnes of CO2 as a byproduct is eminently feasible.

Example: SUV driven 18000 miles/year at, say, 15mpg US: 114,000lbs of air consumed, representing nearly 24,000lbs of oxygen to be bound up in combustion products. That's TWELVE tons of shit right there...