Greenway Self-Park is an 11-story energy-efficient parking garage located in the popular River North neighborhood. This first-of-its-kind structure in Chicago is currently pursuing LEED certification."Clients across a wide range of sectors have been asking us for architectural solutions that push the sustainable envelope," says Todd Halamka, Director of Design for HOK's Chicago office. "For this assignment, Friedman Properties gave us the opportunity to collaboratively envision what a 'green' parking garage could be. Our design is sustainably astute and sets a new standard for this building type."Sustainable design initiatives for Greenway Self-Park include a cistern rain water collection system, electric car plug-in stations, and a way-finding system at each elevator lobby that educates Chicagoans on how to live more sustainably and better protect the environment. Perhaps most significant is a 12-paired array of vertical turbines, located on the southwest corner of the garage, which were designed to harvest the wind to power the exterior wall lighting of the facility. A reversible meter was also installed to measure and return power to the city's grid throughout the year."Parking garage designs in Chicago have had a long tradition of disguising themselves as office buildings with false fades," added Halamka. "Our design attempts to break from that model and deliver an entirely new aesthetic." HOK's team worked closely with client Friedman Properties to create a practical, yet architecturally distinctive garage. In a departure from the typical, closed-exterior-wall design (one that requires 24-hour mechanical ventilation) used on other parking garages, the team conceived a naturally ventilated exterior wall design, utilizing a glazed screen that eliminates the need for a mechanical system entirely. This unique glazed screen is comprised of a visually layered fabric of breathable glass channels that progressively reveal the inner concrete super-structure of the building. Together, the screen and channels provide an interesting visual play from day to night, throughout the 24-hour operation of the garage. The ground-level floor of the garage is reserved for retail space.