3 ms·

Toronto has something similar to this, but instead of a massive water chiller, there’s a set of 3-mile long intake pipes from the permanently cold (4°C / 39F) d

Toronto has something similar to this, but instead of a massive water chiller, there’s a set of 3-mile long intake pipes from the permanently cold (4°C / 39F) deep waters of Lake Ontario. The Deep Lake Water Cooling (DLWC) system supplies over 75 buildings in downtown Toronto and dramatically reduces energy consumption compared to traditional chillers. Curious that they can’t do this in Chicago, too. Are Lake Michigan’s waters that much warmer, shallower than Lake Ontario?

Scoundreller 3y ago
To partly answer your question, Lake Michigan isn’t that deep close to Chicago, so it doesn’t stratify to have that constant 4C depth of water nearby. Contrast that to Toronto on Lake Ontario where the depths (and temperatures) drop off quickly: Lake Michigan (Chicago is near the bottom left): https://www.mlive.com/resizer/ShCu4LXkI1ioIVtd5mmLimlPt_M=/800x0/smart/cloudfront-us-east-1.images.arcpublishing.com/advancelocal/NIVILEEL6RGSRBKO3ZEIC5KHQE.gif https://www.mlive.com/resizer/ShCu4LXkI1ioIVtd5mmLimlPt_M=/8... Lake Ontario: (Toronto is right where it’s bluest/coldest): https://www.mlive.com/resizer/13wrdcYuMUdx3A_4kycmNO_XhpY=/800x0/smart/cloudfront-us-east-1.images.arcpublishing.com/advancelocal/V6WC3F7LV5AV7IMUIUFSUWUTGY.gif https://www.mlive.com/resizer/13wrdcYuMUdx3A_4kycmNO_XhpY=/8... Source article: https://www.mlive.com/weather/2020/08/see-how-cold-it-is-at-the-bottom-of-the-great-lakes-this-summer.html https://www.mlive.com/weather/2020/08/see-how-cold-it-is-at-... Toronto’s system works with heat-exchangers on incoming municipal water. Possibly working with already warmer water would present in-system microbial growth issues in Chicago. I think Toronto’s intake pipes were intentionally that deep because that water mixes the least with crap (literal and figurative) from the surface, not to make this cooling system more efficient. The downside is that city users get warmer than otherwise water in summer, so their own A/Cs need to work a bit harder with the warmer water in your toilet tank and pipe work. And commercial/industrial evaporative air conditioners are starting off with slightly warmer water. But water heaters have a bit less work to do (great if resistive, bad if heat pump). And of course, chilly water in winter (but it is nice to be able to get pretty cool tap water year round).
- Reason077 3y ago
  The three long, deep-water intake pipes were built as part of the original DWLC project, commissioned in 2004. Access to deep cold water is an important benefit of the system, but you're correct that they have a dual purpose, and access to cleaner water for the municipal supply was presumably a side benefit. As part of a system expansion, they are currently building a 4th intake which would re-use one of the original, shallower municipal water intakes which was obsoleted by the 2004 system. This would be extended to reach colder water and would bypass the city water treatment plant to deliver raw water directly to the DLWC: https://www.toronto.ca/community-people/get-involved/public-consultations/infrastructure-projects/deep-lake-water-cooling-expansion-study/ https://www.toronto.ca/community-people/get-involved/public-...
- Kon-Peki 3y ago
  Highly recommend using the Great Lakes Bathymetry page, much better detail on lake depths, as well as shape files and data :) https://www.ncei.noaa.gov/products/great-lakes-bathymetry https://www.ncei.noaa.gov/products/great-lakes-bathymetry Lake Ontario (The dot that says "Toronto" is the airport. Toronto the city continues well to the east, and the water intake pipes go out into the lake in the section where it gets very deep very quickly, almost as if they planned it well or something): https://www.ngdc.noaa.gov/mgg/image/images/ontario_wallsize_300.pdf https://www.ngdc.noaa.gov/mgg/image/images/ontario_wallsize_... Lake Michigan near Chicago (Chicago has two active municipal water intake cribs, both about 2.5 miles out into the lake. The water is only about 30-40 feet deep at those points): https://www.ngdc.noaa.gov/mgg/image/images/michigan_wallsizebot_300.pdf https://www.ngdc.noaa.gov/mgg/image/images/michigan_wallsize...
  - trillic 3y ago
    Detroit's water is similarly brought in from an intake a few miles off the shores of Lake Huron. Similar depth of 30-40ft.
    - deleted 3y ago
      [deleted]
    - 3y ago

Scoundreller 3y ago

To partly answer your question, Lake Michigan isn’t that deep close to Chicago, so it doesn’t stratify to have that constant 4C depth of water nearby. Contrast that to Toronto on Lake Ontario where the depths (and temperatures) drop off quickly: Lake Michigan (Chicago is near the bottom left): https://www.mlive.com/resizer/ShCu4LXkI1ioIVtd5mmLimlPt_M=/800x0/smart/cloudfront-us-east-1.images.arcpublishing.com/advancelocal/NIVILEEL6RGSRBKO3ZEIC5KHQE.gif https://www.mlive.com/resizer/ShCu4LXkI1ioIVtd5mmLimlPt_M=/8... Lake Ontario: (Toronto is right where it’s bluest/coldest): https://www.mlive.com/resizer/13wrdcYuMUdx3A_4kycmNO_XhpY=/800x0/smart/cloudfront-us-east-1.images.arcpublishing.com/advancelocal/V6WC3F7LV5AV7IMUIUFSUWUTGY.gif https://www.mlive.com/resizer/13wrdcYuMUdx3A_4kycmNO_XhpY=/8... Source article: https://www.mlive.com/weather/2020/08/see-how-cold-it-is-at-the-bottom-of-the-great-lakes-this-summer.html https://www.mlive.com/weather/2020/08/see-how-cold-it-is-at-... Toronto’s system works with heat-exchangers on incoming municipal water. Possibly working with already warmer water would present in-system microbial growth issues in Chicago. I think Toronto’s intake pipes were intentionally that deep because that water mixes the least with crap (literal and figurative) from the surface, not to make this cooling system more efficient. The downside is that city users get warmer than otherwise water in summer, so their own A/Cs need to work a bit harder with the warmer water in your toilet tank and pipe work. And commercial/industrial evaporative air conditioners are starting off with slightly warmer water. But water heaters have a bit less work to do (great if resistive, bad if heat pump). And of course, chilly water in winter (but it is nice to be able to get pretty cool tap water year round).

Reason077 3y ago
The three long, deep-water intake pipes were built as part of the original DWLC project, commissioned in 2004. Access to deep cold water is an important benefit of the system, but you're correct that they have a dual purpose, and access to cleaner water for the municipal supply was presumably a side benefit. As part of a system expansion, they are currently building a 4th intake which would re-use one of the original, shallower municipal water intakes which was obsoleted by the 2004 system. This would be extended to reach colder water and would bypass the city water treatment plant to deliver raw water directly to the DLWC: https://www.toronto.ca/community-people/get-involved/public-consultations/infrastructure-projects/deep-lake-water-cooling-expansion-study/ https://www.toronto.ca/community-people/get-involved/public-...
Kon-Peki 3y ago
Highly recommend using the Great Lakes Bathymetry page, much better detail on lake depths, as well as shape files and data :) https://www.ncei.noaa.gov/products/great-lakes-bathymetry https://www.ncei.noaa.gov/products/great-lakes-bathymetry Lake Ontario (The dot that says "Toronto" is the airport. Toronto the city continues well to the east, and the water intake pipes go out into the lake in the section where it gets very deep very quickly, almost as if they planned it well or something): https://www.ngdc.noaa.gov/mgg/image/images/ontario_wallsize_300.pdf https://www.ngdc.noaa.gov/mgg/image/images/ontario_wallsize_... Lake Michigan near Chicago (Chicago has two active municipal water intake cribs, both about 2.5 miles out into the lake. The water is only about 30-40 feet deep at those points): https://www.ngdc.noaa.gov/mgg/image/images/michigan_wallsizebot_300.pdf https://www.ngdc.noaa.gov/mgg/image/images/michigan_wallsize...
- trillic 3y ago
  Detroit's water is similarly brought in from an intake a few miles off the shores of Lake Huron. Similar depth of 30-40ft.
  - deleted 3y ago
    [deleted]
  - 3y ago