IPRO 338 retrofits existing structures for Smart Grid technology

Sunday, April 28th, 2013

IPRO 338: Techno Economic Analysis of Electrical Smart Grid Technology Solutions Retrofitting the Soldier Field Parking Structure Overall Project Summary.

IPRO 338 revolves around the techno-economic analysis of a pre-existing structure (in this case a parking garage) and proposing ideas that could be used in order to make said structure more energy efficient and sustainable. This IPRO is also taking part in this year’s NECA Green Energy Challenge. Its goals are similar to the IPRO program, but teams from across the nation from several top schools compete in order to come up with the most innovative and energy efficient solutions for their respected sites.

The site for our team’s audit is the parking structure for the Chicago Bears home field, Solider Field. In addition to the Bears games, this field hosts events almost daily, ranging from weddings, soccer games, mega concerts and more. This parking lot is also the heart of Chicago’s historical Museum Campus, which is home to the Shedd Aquarium and Field Museum. The structure is built underground and hosts 4 levels with space for 2,500 cars. The roof of the parking lot is the second largest green roof in Chicago. The site provides a unique challenge because Solider Field, including the parking lot, is the first LEED certified football stadium in the NFL. The site selection for our audit provided a unique challenge to provide new efficient technologies in a high traffic and already highly efficient structure. The proposed retrofits have the potential to provide a huge impact on energy usage for a site that services a large amount of the Chicago population. This iconic campus will benefit highly from our detailed research and proposal (which will be summarized here).

Lighting Retrofit:

During our investigation of the existing lighting system, we unfortunately were not able to track down the model numbers. This prevented us from being able to look up the manufacturer’s specifications that could tell us the input wattages for each existing fixture. We know that the input wattages for lighting fixtures are almost always higher or lower than the sum of the bulb wattages. However, for the purpose of our analysis we made the assumption that the existing fixture wattages are equal to the sum of their bulb wattages. Thus, after examining the existing lighting system for the garage we concluded that the total saving in energy cost would be around 55% of the original amount if LED light fixtures are implemented (see Lighting Retrofit Graph).

Solar Retrofit:

We proposed that an elevated solar panel structure be placed on the two ventilation exhaust areas located on the east and west sides of the garage. The system will connect directly to the grid for Soldier Field and the garage, so no batteries will be needed. We found the system to be economically viable if state and federal rebates and grants can be taken advantage of to the fullest extent. The system will have the added benefits of improving the garage’s public image and giving the site more LEED points, possibly leading to an increased LEED rating.

EV Charging Station Retrofit:

The management team of the North Garage at the museum campus in Chicago has made great efforts in creating and maintaining an ecologically friendly and energy efficient structure. To this end, three electrical vehicle-charging stations have been installed in the north garage only for visitors attending events at Soldier Field and surrounding museums. Our project plan was to analyze the existing conditions of the charging stations and propose improvements as necessary in order to increase the garage’s energy efficiency. In turn, this has led us to the conclusion that a new EV charging station will raise the overall uptime of the charging system (see EV graph for a comparison against gas powered vehicles).

Thermal Retrofit:

The thermal team was dedicated to improving the efficiency of the HVAC system in the Soldier Field North Parking Garage. The parking garage is a multi-tiered underground structure composed of precast concrete sections. Due to the nature of this construction and placement, the opportunity for natural ventilation was non-existent, necessitating the use of a forced air system. The HVAC system does not provide any space conditioning, as its only duty is to provide fresh air to the parking garage, and remove the air contaminated with vehicle exhaust. Our team concluded that the best course of action would be to install variable frequency drives, which would control the flow of the system more efficiently (rather than an always on or always off system, see Thermal Retrofit graph).


Our presentation and exhibit at this year’s IPRO day won us top honors within our respected track (Track 2: Energy and Sustainability) and it is our hope to place within the top three for this year’s NECA Green Energy Challenge in which the finalists are flown to Washington DC to present their work.

Project Team: Dr. Dan Tomal (Professor), Chenqi Bao, Nikhil Bhasker, Nick Caldwell, Jungmin Cho, David Jarma, Jeffrey Johnson, Daniel Medrano, Frank Morris, Eric Neubauer, Dustin Shahidehpour, Amen Soudy, Gary Sterna, Yuanbin Wang, Junyu Yan, Fengrui, Yang Denise Philippi.