The research component of the DSH is multivalent; research initiatives will emanate from students, faculty, industry and/or the public. This rich mix of players will particularly nourish the entrepreneurial spirit that has characterized the DSH. To help structure and give focus to research centered around sustainable, design-based research problems, particularly as they relate to the “wicked problems” that confront low and moderate sustainable housing in the United States, it is proposed to collaborate and partner in evolving plans for an Urban Sustainability Institute.

Consistent with the tradition and spirit of the DSH, the DSH research and education initiative would initially address a highly visible low and moderate income urban sustainable “wicked housing problems” that would be constructed and modeled, both digitally and physically. Students and faculty across the University would receive the challenge. For instance, is it possible to develop an equivalent SIP (structural insulated panel) system that traditionally provides the super insulation needed for new Passive House construction that would serve for renovation projects? Or, can cargo containers be designed and then used to provide temporary shelter after a catastrophic event?  Such challenges would link coursework with research as well as with product development, all of which are consistent with the traditions and history of the DSH as well as with the experiential learning opportunities Drexel is known for across the nation and the world.

Bringing Daylight Indoors

A partnership with Summalux LLC, a Baiada Center Incubator Company and Drexel Smart House Spin-off

The built environment presents significant challenges to designers seeking to maximize daylight integration. Further, indoor spaces incorporating significant amounts of daylight have been shown to enhance occupant productivity and health, most notably by regulating the circadian rhythm, preventing seasonal affective disorder (SAD), and other conditions such as shift work dysfunction. Daylight simulation, made possible by energy efficient LED technology, has the potential to reproduce the benefits of natural sunlight. These lighting products are especially suited for commercial spaces with limited sunlight exposure, as well as residential and retail environments.

Recent advances in LED packaging, power conversion drivers, and thermal management technology are making LED lighting products more affordable for general use. Drexel Smart House and Summalux LLC plan to outfit the entirety of the 3425 property with daylight simulation lighting fixtures and study the impact on occupant health and productivity.

Cool Roof Coatings

Sponsored by the U.S. Environmental Protection Agency

Also supported by the Dow Chemical Company, Advanced Materials Division and Potter's Industries

This project's goal is to develop a low cost cool roof coating formulation which improves upon the infrared reflective properties of commercially available white coatings. This is accomplished by incorporating novel materials with unique optical properties and specially engineered pigments and additives into a water based acrylic binder. This project is part of the Smart House's Heat Island Mitigation research initiative.

Solar Gain is in part responsible for up to 56% of energy consumed by cooling systems in residential buildings1. Additionally, high building density in the urban environment contributes to the urban heat island effect. According to the EPA2, regions exhibiting the urban heat island effect can be as much as 10ºF warmer than their rural counterparts, and these regions may see as high as a 22ºF difference in temperature between day and night. Mitigating the urban heat island effect has the potential to reduce cooling demand, peak demand, and heat related illnesses and fatalities.

By applying cool roof coatings to a building's exterior, cooling loads can be reduced and urban heat islands can in part be mitigated.3 Many commercially available cool roof coatings are white paint formulations based on titanium dioxide.4 Although titanium dioxide and other pigments are effective at scattering visible wavelengths, they exhibit strong absorption in the infrared region.5 By incorporating controlled voids in a coating as the scattering medium, the void size distribution can be optimized for broadband radiation scattering.6 The purpose of this project is to design a coating utilizing glass hollow microspheres as a means of controlling void diameter to achieve a low solar gain roof.

Glass Hollow Microspheres are the primary filler in our coatings. Our current formulation has been specially designed to promote polymer binder - sphere adhesion while preventing sphere breakage, visible in two of the above images. Images © 2009 Drexel University, Department of Materials Science and Engineering.

1. Department of Energy. 2007 Buildings Energy Data Book, U.S. Department of Energy.

2. Environmental Protection Agency. "Reducing Urban Heat Islands: Compendium of Strategies" Retrieved March 12, 2009. pdf/BasicsCompendium.pdf

3. Environmental Protection Agency. "Reducing Urban Heat Islands: Compendium of Strategies - Cool Roofs" CoolRoofsCompendium.pdf
4. J. Beltley and G. P. A. Turner, Introduction to Paint Chemistry and Principles of Paint Technology, 4th ed. (Chapman and Hall, London, 1998), p. 105-106, 110.

5. Cole, Joseph R; Halas, N.J. Optimized Plasmonic Nanoparticle Distributions for Solar Spectrum Harvesting. Appl. Phys. Lett. 89, 153120 (2006).

6. Dombrovsky, Leonid A; Randrianalisoa, Jaona H; Baillis, Dominique. Infrared radiative properties of polymer coatings containing hollow microspheres. Intl. J. of Heat and Mass Trans. 50 (2007) 1516–1527
This research has been supported by a grant from the U.S. Environmental Protection Agency's Science to Achieve Results (STAR) program.

Residential Green Roof System

One of our latest projects, the residential green roof group seeks to develop a green roofing structure and system suitable for integration in residential properties. One of the challenges faced by the team early on was the structural evaluation of the 3425 property. Since an evaluation was recently carried out on the property, design requirements have been set and the team is planning to design a green roofing platform suitable for installation on the original roof structure of a 19th century Victorian twin home.

The most significant challenge the team is faced with is identifying a light weight replacement for the growing medium (most commonly soil or clay) that can be sourced within 500 miles of the installation site. Sourcing perlite, a lightweight volcanic soil, on the east or west coasts is feasible since it is mined on both coasts. Shipping perlite over 500 miles to the midwest incurrs a carbon footprint, since fuel is used for the transport of perlite. LEED outlines how building materials should be sourced, and specifies a 500 mile radius for it's local materials point.

This growing medium must balance high water retention with good drainage properties while supporting plant life. Smart House researchers use several test methods to measure water retention and drainage, as well as freeze stability, density, erosion, and pH.

Further impacts of this research include the potential for sloped green roofing systems and vertical outdoor walls.

Green roofs have the potential to reduce a building's environmental impact by offering water retention, thereby reducing water runoff to surrounding areas. Additionally, the roof vegetation serves to reduce cooling loads by reducing heat gain. Significant implementation of green roofs and cool roofs can in part mitigate the urban heat island effect.