How Chicago Solves its Overheating Problem

I'm touring places in Chicago to check out different approaches for keeping cool when the weather is hot this region is known for its brutal Winters but its intense summer heat can also present deadly problems after a particularly lethal heat wave in 1995 Chicago implemented a number of design related initiatives to keep its citizens safe from hot weather disasters cities in general are prone to something called a heat island effect where its impervious dark surfaces generate and trap heat this raises the temperature of the city almost 10 degrees Fahrenheit compared to even nearby surrounding suburbs combined with a greater density of people and the severe heat of summers in urban areas can pose serious dangers to human safety solving this with air conditioning alone comes at a hefty cost it provides relief indoors but achieves it by effectively pushing the heat outside and doing that comes with an overall net loss when you factor the energy of forpowering that process so with AC cooling one space means warming others even more that's why AC is credited as a primary contributor to global warming so I'm exploring the city to learn a little bit more about how materials physical design and strategic geography are specifically chosen to provide thermal comfort for people our final stop will be a recently completed building that combines a number of these strategies until it barely needs any mechanical air conditioning at all so let's get to it I have to say that there's some pretty bold and clever stuff around here the eagle-eyed among you might have noticed that I'm standing in the world's largest green roof and Millennium Park a green roof complete with the thick beds of soil that insulate and with the vegetation that shade can yield a 30 to 40 degrees Fahrenheit lower temperatures indoors when compared with a conventional roof they can also reduce city-wide ambient temperatures by up to 5 degrees Fahrenheit Chicago currently has 509 green roofs many are the results of the 2004 sustainable development policy which ties access to City funds for new projects to the mandatory inclusion of sustainable strategies like ones that keep buildings cool by using less energy green roofs work no matter where they are in the skyline whether they're up in the air or here closer to sea level trees and vegetation always lower surface and air temperatures by providing shade as well as through processes like evapotranspiration shaded surfaces for example may be 20 to 45 degrees cooler than the peak temperatures of unshaded materials by reducing demand trees and vegetation decreases the production of Associated Air Pollution and greenhouse gas emissions they also remove air pollutants and store and sequester carbon dioxide even if horizontal surfaces like a roof can't have vegetation just changing its color can have a profound effect you notice that the material under my feet is a bright color which reflects the sunlight turning less of it into surface Heat this effect is measured with a factor called Albedo which is the proportion of the incoming solar radiation reflected by the various surfaces in the urban environment which yields a reflection coefficient defined as the ratio of incoming to outgoing radiation so the higher the Albedo the better and it can be calculated using satellite imagery Millennium Park raised to this area's reflectivity ratio by a few percentage points overall good for lowering the temperature a couple of degrees on any given day color and trees aren't the only thing keeping this area cool Millennium Park is also home behind me to Crown Fountain which in addition to providing a place for folks to Splash around creates a unique microclimate around it that you can feel when you're nearby that local change in atmosphere comes from two things the first is evaporation when water is sprayed or pumped into the air it increases the exposed surface area so evaporation occurs more rapidly evaporation is a cooling process that absorbs heat from the surrounding air reducing its temperature when water droplets evaporate they take away some of the heat energy making the surrounding area feel cooler where did the water go it went into the air it evaporated and there's also convective cooling the movement of water in a fountain creates little air currents as air passes over the water surface it picks up moisture and heat is transferred from the surrounding area to the water the moving air creates a breeze which makes people nearby feel a little bit cooler these are all passive strategies that create cooling effects Outdoors without the need for mechanical methods of dropping temperatures like air conditioning big buildings though are very difficult to keep cool and will require air conditioning no matter how well that they're designed but there are better ways to do this than others the city here deploys something called District Cooling and this is the largest version in the United States District cooling is when a group of buildings cooling needs are partially supplied by a central plant rather than entirely with equipment located within the building itself it can be done slightly differently depending on local geography and weather but here in Chicago there are five plants that Supply water at just above freezing temperatures to each of the 115 buildings that is serviced by the system this saves around 20 percent of overall cooling costs and it's also a much more sustainable practice and it saves space and Equipment within the buildings that are serviced by it this is done by concentrating the infrastructure all within a single efficient system buildings on this system no longer require chiller or cooling towers up on their roofs you here at production plan number two it's one of those five plants whose job it is to make warmer water that's already been supplied to buildings and then cool it back down again ready for reuse where you're looking at above ground here is a massive concrete water storage tank where they cool the water and keep it till it's needed the tank is about 100 feet long 90 feet wide and 30 feet high it holds 23 000 tons of water that is also filled with 435 miles of tubing and 434 cooling units through these tubes run super chilled glycol basically antifreeze this cools the water forming ice around the metal coils they run everything at night while electricity demands are lower and ice up the system the ice then works like a temperature battery that is discharged during the day by pumping the water through the system of pipes from the plant the water comes out of here at 34 degrees Fahrenheit just above freezing which is taken in at each building which uses an energy transfer station where it can be used to cool another closed loop system that powers Air Handlers on various floors so let's head to open supplies to see how they supplement this cold water with their own strategies for staying cool right here is an amazing juxtaposition of two buildings with vastly different approaches to cooling on this side is the minadnock building which was built in 1893 by the architect Daniel Burnham and it was built way before air conditioning was used in Office Buildings like this so it utilizes a number of passive design strategies for keeping cool across the street is Federal Plaza by Mesa vandero built around 80 years later and it embodies basically a modern attitude toward keeping cool and large Urban buildings it would not be an inhabitable structure without mechanical air conditioning so one of these two buildings do differently to stay cool the U.S energy Department's data shows that pre-1920 commercial buildings use less energy per square foot than those built at any other time during the 20th century that's because staying cool was integrated into their design from the start the banana Arc has a thick facade made of brick punctured by windows that open up to the outside the thick massive walls take a long time in the Sun for the building to warm up their release is hit at night while it's cooler and when no one's really in building that's all in contrast to the federal building's wafer thin facade of mostly glass when sunlight hits it you feel it immediately the facade doesn't have the thermal mass of the Monadnock which for the heavy building acts as a sort of temperature inertia keeping it cool throughout the day both buildings are rectangular but the Monadnock is exceptionally long and narrow the interior is a generously wide hallway of offices flanking both sides the original design called for transom Windows which allowed breezes to flow right through the building this is also in contrast to the federal buildings whose windows don't even open so any air that flows through the building has to do so using mechanical means it's also a building that's filled with closed courtrooms that need to remain sealed from many other spaces each courtroom actually has its own air handling unit and since the building was built its cooling needs have changed drastically to the point that some of its original heating infrastructure was converted into cooling due to all the computers and people producing more heat than they did in the 1960s some buildings today try to incorporate these lessons into their design to move past the kind of thinking that gave us buildings like mises Federal Plaza but ironically sometimes that means looking back to the strategies of the Monadnock and the architect Daniel Burnham from over 100 years ago the Schreiber Center was originally envisioned as a vertical campus so we came up with this idea of an Atrium thinking that the atrium would connect everybody um that in the end provided both natural light into the space we also used it as a way to create natural ventilation that pulls air in from the facades and brings it out through the uh the top of the atrium my name is Devin Patterson I'm a principal at SCB my lead design for academic projects nationally across the country the way that the atrium works is by heating the top of the atrium induces a natural sort of suction that pulls air in from the sides to create a natural cross ventilation in the classrooms and the offices and in the corridor so if you looked at older buildings they provided shades on the outside of the building so there might be an awning or something like that which would cover up a window that would protect the window from the harsh sunlight so we took this to a different level with this building we came up with this automated venetian blind that kind of tilts and closes down to protect the building from sunlight coming in and then also opens up to allow sunlight to come in when the sun is high so we did these these detailed models to really understand sort of the relationship of the working elements of of the of the building that provide the natural ventilation and then you can see inside that facade that's where the shade lives inside the facade the windows themselves are also designed to have this shade strategically placed here a professor can open or close their window based on that building automation system telling them to do that the punch windows on themselves are actually sort of high-tech as well and that was really the key to reducing energy consumption on the campus campus-wide by almost 30 percent over 10 years while many of these Urban cooling strategies are largely invisible they contribute significantly to making the city a much more livable and a sustainable place to live extreme heat can be more than just an issue of comfort and often staying cool is presented as a direct challenge to the environment at large to stay cool inside means slowly making the globe incrementally warmer but as we've seen this isn't always the case sometimes we can look back to practices from over 100 years ago and they're just as cool today as they were then in preparation for this video I brushed up on my scientific thinking skills around heat transfers and airflow I was able to do this in the most engaging and entertaining way possible over on brilliant brilliant walked me through on a series of lessons using a pot of water on a stove the lessons are so well designed that they feel like a game you can turn stove knobs and watch the physics unfold it really helps sharpen my thinking around the science of heating up and staying cool all this is what makes brilliant great keeps me sharp while exploring the world on my own time like a personal learning coach obviously continuous learning is essential for our careers and just satisfying our curiosity staying up to date on the latest Innovations and keeping mentally sharp brilliant makes it easy to build a daily learning habit it's visual Hands-On approach is such an effective and engaging way to master the key Concepts behind today's technology and you can do it anywhere on all sorts of devices I'll start one on my computer and pick it up later in the day on my phone really was built for busy people with bite-sized lessons that break down important Concepts into understandable parts and they have thousands of lessons from foundational and advanced math to AI data science neural networks and more with new lessons added every month to try everything that brilliant has to offer for free for a full 30 days visit brilliant.org Stuart Hicks or click on the link in the description the first 200 of you will get 20 off brilliant's annual premium subscription enjoy if you enjoyed this video please considering that like button and subscribe to the channel if you haven't already leave a comment with your thoughts about staying cool in the comments section below and while you're there check some of these other videos which come out every other Thursday see you over there

Channel: Stewart Hicks

Views: 519,117

Keywords: architecture, design, architecture student, architecture design, architecture lecture for beginners, architecture 101, architecture documentary, architecture concept, architecture theory, stewart hicks, architecture talk, urban design, chicago, lethal heatwave, hot weather disasters, heat island effect, human safety, AC (air conditioning), global warming, materials, physical design, thermal comfort, green roofs, sustainable strategies, air pollution, district cooling.

Id: _Bvg7x7uAdk

Length: 13min 12sec (792 seconds)

Published: Thu Jun 29 2023