Urban alleyways. Grubby places that only scrappy cats or cop-show perps could love, right? Not in Chicago, where the Department of Transportation is giving them some serious TLC with its recently implemented Green Alley Program. This city-wide renovation initiative will offer some surprising environmental benefits and improve quality of life for residents.
Alleys may seem like a tiny fraction of a city’s infrastructure. But Chicago has more than any other city in the world – 1,900 miles of alleyways that translate to 3,500 acres of paved landscape. And traditional alley designs have been plagued with flooding problems that overwhelm the city’s sewers, plus they can worsen nighttime light pollution and trap heat in the summer months. In response to this, The Chicago Department of Transport has followed the lead of Portland and companies like Aviva and Johnson & Johnson who have introduced impressive green initiatives. The four basic components of Chicago’s Green Alley program are effective stormwater management, minimizing heat absorption, creating designs to reduce light pollution, and maximizing the use of recycled materials wherever possible.
Using permeable pavement along with proper grading for drainage is a key element of managing water runoff. Paving materials that let rainwater infiltrate the soil (instead of entering the sewers) allow groundwater to be recharged, and reduce unnecessary stress on water treatment plants. A variety of pavers are being used, including permeable asphalt and concrete materials as well as open grid-style pavement tiles.
The “heat island” effect that occurs when paved surfaces absorb the sun’s rays can substantially increase ambient temperature (and energy demand) in the summer months. The Green Alley program mandates the use of high-albedo (light-colored) pavements that absorb minimal heat. Benefits include reducing the need for air-conditioning in surrounding structures, and creating a better environment for vegetation growth.
Nighttime light pollution means that in most urban areas, a starry sky is a rarity. The Green Alley program requires the use of directional light fixtures that give street-level illumination for residents without shining upward into the sky. The new fixtures also provide a natural white light instead of the ubiquitous yellow glow seen from older sodium lamps.
Using recycled construction materials is also crucial for the Green Alley program, and creates cost savings while reducing raw material consumption and stress on landfills. Recycled concrete aggregate is being used in both foundation and surface layers, and reclaimed asphalt and ground tire-rubber can be used in pavement. Slag waste from steel production can also be used in the concrete components of the projects.
The Green Alley upgrades are being gradually implemented throughout the city. The Department of Transportation is also working with property owners to encourage their involvement in the Green Alley program, by providing maintenance advice and encouraging projects like rain gardens to complement the new alley designs.
(Via Chicago Department of Transportation)
way to go Chi-Town going green, and might even get the olympic bid! Steps in the right direction too one day being fully green.
This is an awesome idea! I don’t know why we havent been doing it for years!
Egg Systems has been in the news for over 19 years showing the public how they can save money and the environment using Geothermal Technology.
Remember, a geothermal heat pump doesn’t create heat by burning fuel, like a furnace does. Instead, in winter it collects the Earth’s natural heat through a series of pipes, called a loop, installed below the surface of the ground or submersed in a pond or lake. Fluid circulates through the loop and carries the heat to the house. There, an electrically driven compressor and a heat exchanger concentrate the Earth’s energy and release it inside the home at a higher temperature. Ductwork distributes the heat to different rooms.
In summer, the process is reversed.
The underground loop draws excess heat from the house and allows it to be absorbed by the Earth. The system cools your home in the same way that a refrigerator keeps your food cool – by drawing heat from the interior, not by blowing in cold air.
The geothermal loop that is buried underground is typically made of high-density polyethylene, a tough plastic that is extraordinarily durable but which allows heat to pass through efficiently. When installers connect sections of pipe, they heat fuse the joints, making the connections stronger than the pipe itself. The fluid in the loop is water or an environmentally safe antifreeze solution that circulates through the pipes in a closed system.
Another type of geothermal system uses a loop of copper piping placed underground. When refrigerant is pumped through the loop, heat is transferred directly through the copper to the earth.
As with any heat pump, geothermal and water-source heat pumps are able to heat, cool, and, if so equipped, supply the house with hot water. Some models of geothermal systems are available with two-speed compressors and variable fans for more comfort and energy savings. Relative to air-source heat pumps, they are quieter, last longer, need little maintenance, and do not depend on the temperature of the outside air.
Egg Geothermal Heating and Cooling uses the Earth’s constant temperature to achieve EER’s (Energy Efficiency Ratings) in the 30’s. The heating COP (Coefficient of Performance) is approaching 5. A 5 COP indicates that the Egg Geothermal Systems are producing 5 units of energy for every unit of electricity consumed. The other 4 come from the Earth. That’s why this technology is called “renewable”.
Is this being done on Chicago city streets too? Seems like it would be a bigger priority before doing the alleys. Cool idea though.