Solar Energy Conversion R&D efforts
The development of low-cost solar photovoltaics is inherently dependent on scalable manufacturing practices of the materials and processes involved. The Conn Center is establishing a unique, flexible manufacturing R&D line for developing cost-effective solar cell technologies for large-scale energy production. Interests include developing various thin film materials and technologies and demonstrating their ability to be economically manufactured using the roll-to-roll facility. The University of Louisville has been actively involved in the development of new materials for third generation solar cells and is uniquely positioned to scale these technologies. The facility will develop sustainable manufacturing processes utilizing low energy techniques with the goal of producing the lowest life cycle cost for photovoltaic devices.

- Low cost and scalable solar cell technology:
- Low cost, transparent conduction substrates
- Low cost organic photovoltaics
- Higher efficiency enabled through nanotechnology
- Low cost, efficient and stable thin film absorbers
- Flexible, roll-to-roll manufacturing R&D:
- Thin composite films for conducting substrates
- Thick film technology for solar absorbers
- Rapid testing of potentially transformative material and device concepts in a manufacturing environment
- Low temperature processing polymer substrates
- Scalable, low energy processes for foils

Solar Manufacturing Research and Design Laboratory
Goals - The Solar Manufacturing R&D Lab at the Conn Center is able to assist researchers in implementing designs, materials, and processes into scalable manufacturing platforms with demonstration devices. The facility maintains the capabilities to design and manufacture large-area solar cells over multiple platforms, including first and second generation technologies with an emphasis on the breakthrough of third generation technologies. The facilities include the capabilities for continuous (roll-to-roll) production of photovoltaics. The roll-to-roll manufacturing is also adaptable to other technologies such as electrochromics, OLEDs, thin film batteries, and fuel cells. The center is capable of incoming quality control and utilizes materials characterization equipment at the Conn Center to facilitate qualification of solar and renewable devices. These abilities allow collaborations among University of Louisville researchers with fellow academics and industry partners across Kentucky.
Design - We are capable of assisting researchers in the design of solar photovoltaics, active and passive fenestration, and thin film flexible devices. Innovative designs that deviate from flat panels are the focus of production scale up and are uniquely positioned to address economics, weathering, constrained spaces, and the personalization of energy.
Materials - We develop vendor relationships required to ensure that the materials required (conductive glass, plastics) are available for small-scale production. Researchers are also advised on the costs and volumes of materials required for roll-to-roll fabrication.
Thin film designs - We can design solar cells as well as components such as concentrators, light trapping, and anti-reflection coatings using computational modeling.

Production Scales
Small Scale (verification) - We maintain the capabilities to design and manufacture single cells over multiple platforms, such as crystalline silicon, thin film crystalline, and organic thin film. These facilities are used to assist researchers to move their ideas from lab scale to demonstration. We maintain the equipment to build several types of cells and emphasize proper environmental health and safety handling of processes.
Mid Scale (continuous) - Beyond the capabilities to manufacture small-scale solar cells, the Conn Center focuses on continuous (roll-to-roll) fabrication of solar cells. This line is dedicated toward low energy production methods. Our equipment is configured to allow for multiple deposition techniques as well as development of in-line process control. This capability allows us to build economic models for large-scale production. Equipment includes a modular roll-to-roll coating assembly for coating flexible substrates and is capable of unwind/rewind, deposition, and curing as well as rapid reconfiguration. In addition, the lab also offers in-line process control for testing devices and feedback control.
Large Scale (implementation) - The final stage of large area deposition is a pilot-scale, continuous roll-to-roll coater for moving promising concepts to real world applications. The center has built relationships with vendors who can assist with pilot and full production.

Testing and Characterization
Equipment located within the Roll-to-roll Laboratory and throughout the Conn Center facility is available to characterize the devices built and to perform performance testing, including long-term exposure studies.

The Conn Center will develop the technologies for cost effective, zero-energy buildings. Such technology development will bring Kentucky the tools that our businesses, schools, and residents need to reduce energy consumption. Toward this initiative, the Conn Center has received funding from E.On to fund an Endowed Chair as the theme leader for Energy Efficiency and Conservation theme.

Energy Efficiency and Energy Conservation: Research, Development, and Testing
Our goal is to conduct research and development of practical, economical, and potentially commercializable technologies to improve energy efficiency and energy conservation. This includes:
- Construction Materials - A significant portion of energy used in the US, including Kentucky, relates to heating and cooling buildings. In an effort to reduce energy use, it is proposed that efforts be made to develop smart materials that use an active envelope to minimize the cooling and heating loads of buildings. This development will be focused on a holistic approach aimed at incorporating both structural and envelope functions. The initial goal of this effort will be to develop materials and assemblies that can function to support the building loading and incorporate phase change and other reactive materials. These include materials with variable conductivity that are designed to minimize the energy needed to maintain a comfortable indoor environment in Kentucky's mixed climate. The investigation will focus on conventional materials and systems in an effort to minimize costs and facilitate acceptance in the construction industry. Finally, every effort will be made to use low cost, abundant materials to ensure that these systems are sustainable and economically viable.
- Electrochromic windows/films - Windows add significant loss or gain of heat due to infrared light transmission. Electrochromic windows or films that can be attached to the existing windows could significantly reduce space cooling demand required during hot, sunny days and reduce the heating demand during sunny winter days.
- Solar heat pipe technology - Solar heat pipe technology can be used for reducing energy demand in several applications: heating swimming pools, reducing heating needs for space heating, increasing heat pump efficiencies, integration into solar water heaters, and providing thermal storage for homes. If implemented on a wide scale, this technology could reduce overall energy demand as well as peak demand in both the winter and summer seasons.
- Smart grid/appliance/building for increasing energy efficiency and enabling peak load leveling or shaving.
- Smart homes/buildings - There is a need for developing cost-effecting and reliable sensors and control and monitoring systems to interface the Smart Grid with the HVAC and appliances within residential homes and commercial buildings. It is also imperative to develop these sensors and systems to operate at low or minimal power and avoid invasive and costly wiring retrofitting.
- Smart Grid initiatives for "customer-centric" energy utilization - Develop and integrate sensors and control systems for enabling customers to make informed decisions to reduce their energy consumption. There is also a need to develop technologies for monitoring and controlling faults and hackers to ensure power quality and grid security.
- Waste heat recovery - Waste heat occurring in process industries (e.g., power and chemical plants), if recovered, can significantly reduce overall energy demand. Similarly, these technologies can be integrated into homes and buildings to reduce peak demand. Such technology can also be utilized for recovering heat from automobile exhaust heat.
- Distributed and utility-scale energy storage - Cost effective energy storage technologies at various scales ranging from buildings to sub-stations to utility scale have a large impact on peak load leveling, ensuring power quality and integration of intermittent energy sources.
- Technology testing and integration for adaptation for Kentucky customers - It is our goal to test various potentially commercializable technologies, which enable energy conservation for Kentucky customers, in terms of their ability to be integrated with other technologies.
- Energy efficiency auditing and outreach to Kentucky schools and businesses. This outreach effort will bring awareness to various schools and businesses about improving energy efficiency and energy conservation through technology adaption. This effort also focuses on educating work forces for technology implementation.

The Conn Center is focused on developing technologies for converting biomass to useful fuels and chemicals. Specifically, the center is interested in lipid and cellulosic biomass conversions to transportation fuels and chemicals. Such capabilities will bring Kentucky new private investors to build plants that process biofuels utilizing our research expertise and innovations.

Biomass raw material for transportation fuels, such as gasoline, diesel, and jet fuels, can be broadly divided into two categories: 1) lignocelluloses containing carbohydrates, i.e., wood, switchgrass, leaves, rice and wheat husks, etc.; and 2) lipids containing (mainly) triglyceride esters, i.e., vegetable and animal fats and greases, waste oils, algae oils, etc. Lignocelluloses can be converted to gasoline, diesels, and jet fuels. Due to their chemical structure of long chain fatty acids, the lipid triglyceride esters are well suited for processing into fuels such as fatty acid methyl ester (FAME) biodiesels, "green" diesels, which are a mixture of hydrocarbons boiling in the diesel range, and bio jet fuels.

Cellulosic Biomass Conversion
Several technical and economic obstacles currently hinder the development of biofuels from biomass. A key bottleneck is the difficulty in breaking down and converting the raw cellulose substrate into simple fermentable sugars, where conversion does not reach or often even approach 100%, even after several days of reaction time. The process is further complicated by the desire to work with high solids content to maximize the product concentration in the fermentable sugar stream, minimize water and energy use, and minimize capital expenditures for larger reactors. Like many industrial applications, working with solids suspensions creates challenges associated with maintaining those solids in suspension as well as other mass and heat transfer issues. Also, power consumption in conventional reactors can become prohibitive on an industrial scale.

By integrating state-of-the-art experimental and computational techniques, we are working to:
- better understand limitations in regard to mass transfer and kinetics of the biomass processing environment;
- comprehend the impact of solids loading on mixing and associated power requirements;
- develop processing strategies to overcome these current limitations; and
- partner with industry to facilitate biofuels and associated economic development in the region.

Accomplishments to date are associated with the development and/or improvement of bioprocessing where existing techniques are limited due to complexities with working media, such as multi-phases, high solids content, and complex flow fields. By 2011, 3 PhD students and 8 Masters students will have completed training in this type of biomass processing.

Lipids to Fuels and Chemicals
The conversion of lipid sources into diesels, jet fuels, and chemicals involves the development of suitable, competitive, and heterogeneous catalysts that can be utilized for Fischer-Tropsch synthesis reactions or hydrotreatment. Key considerations for these conversions involve determining the fatty acid compositions of various lipid sources, testing the effectiveness of basic and acidic catalysts, and resolving post-production quality issues and distribution challenges. In the US, FAME biodiesels must conform to the ASTM D6751-09 specifications; however, FAME biodiesels have NOx cold flow and oxidation/storage stability issues that have not been fully addressed. Similarly, bio jet fuels must adhere to a very low maximum freezing point of -47 degrees C, which has also not yet been resolved. In contrast, "green" diesels possess the advantage of being "drop-in" fuels, as they do not require any change in the existing petrofuels industry infrastructure, such as storage, pipeline transport, or delivery.

Researchers at the Conn Center are working to overcome these challenges. We have developed a process for the production of FAME biodiesels with superior cold flow properties and innovations in the production of biodiesels, green diesels, and jet fuels.

Energy Storage R&D efforts
Energy storage is critical to the development and implementation of renewable energy technologies for providing base load generation. Conn Center investigates various technologies including batteries and solar fuels for storage at various energy and power scales. The energy storage research and development efforts are currently focused on the following areas:

Advanced battery technology for distributed, grid scale, and solar/wind farms
Conn Center is developing roll-to-roll manufacturing methodologies for cost-effective production of large-scale energy storage for solar/wind farms with 10 MW or higher capacities. This is a non-traditional route for manufacturing various advanced lithium ion-based technologies, such as lithium ion rechargeable, lithium-sulfur, and lithium-air batteries. We are also developing electrode materials, suitable solid-state electrolytes, and roll-to-roll production methods and facilities.

Electrochemical and photoelectrochemical generation of fuels
In this technological route, we are developing methods to convert electricity directly into large quantities of suitable chemicals that can be stored for use as needed either as electricity or heat. Our goal is to make either hydrogen or hydrocarbon-based fuels using water and carbon dioxide as feedstocks. Such technologies can be implemented widely if suitable electrocatalysts can be produced that are durable, require low energy for kinetics, are cost-effective, and involve abundant earth materials.

Discovery of new materials and development of cost-effective and scalable methods for their manufacturing are the two most important enabling aspects for advancing most of these renewable and energy efficiency technologies. The Conn Center is focused on developing viable materials and refining their production to meet these criteria. Almost all of the technological challenges with renewable energy and energy storage processes are currently due to our inability to discover:

- Suitable materials
- Processes for making and testing theoretically predicted materials
- Processes for scaling up production of materials that show promise in laboratory tests.

In this regard, the Conn Center’s research agenda is comprehensive. Our interests span from basic- to manufacturing scale research to enable rapid discovery and development of new materials for various renewable and energy efficiency applications. These interests are currently focused in the following areas:

- Chemistry of synthesis for new materials by design for energy conversion and storage applications
- Basic research on nucleation and growth mechanisms of crystals and processes for large-area single crystal quality film growth (Gallium Nitride-related materials for energy efficiency technologies)
- Process development for bulk production of 1-dimensional nanomaterials and their functionalization
- Process development for large-area production of vertical nanowire arrays and graphene
- Process and product development research requires extensive structural and optical characterization of the materials and their surfaces. Using our array of Materials - Characterization equipment and the expertise of our scientists, engineers, and technologists, we have the capability to qualify the performance of advanced energy materials developed at UofL, at research institutions across the state, or by industry partners.

The Conn Center offers numerous opportunities for high school and college students to participate in research. We work closely with groups that have the mission of promoting college education and pre-college participation in research with short-term goals toward participation in science fair competitions. These include various high school groups and the non-profit Lincoln Foundation in Louisville. In addition, the Conn Center supports numerous research opportunities for students at UofL, including the UofL Solar Decathlon Team and the Speed School Engineering Expo.

Science Fair mentoring
Several Conn Center faculty (Sunkara, Cohn, and Sumanasekera) mentor students from Louisville-area high schools each year who win grand prizes at Intel Science Fair competitions and also pursue majors in science and engineering. Every year, these professors also involve about ten high school students in research. These students spend approximately 4-6 hours per week in their labs. In addition, Sunkara and his students offer two hour-long workshops on the fabrication and testing of solar cells to all freshmen in engineering and Louisville Science Center on its annual “NanoDays”.

The Lincoln Foundation is led by the African-American community in Louisville; its goal is to help develop successful leaders in K-12 students by providing year round non-traditional educational programming for academically talented, economically disadvantaged youth. Each year, about one dozen 8th grade students join the program. They meet monthly with the community leaders throughout their 9-12 grades in high school. The Conn Center faculty regularly visit the Lincoln Scholars, to participate in their meetings, and to promote careers in science and engineering.

Solar Decathlon
The Conn Center supports a team of undergraduate students from UofL that compete in the U.S. Department of Energy Solar Decathlon. In this decathlon, 20 collegiate teams design and build energy-efficient houses powered exclusively by the sun. These teams spend almost two years creating houses to compete in 10 contests on the National Mall. The winning team produces a house that is: affordable, attractive, and easy to live in; maintains comfortable and healthy indoor environmental conditions; supplies energy to household appliances for cooking, cleaning, and entertainment; provides adequate hot water; and produces as much or more energy than it consumes.

E-Expo
Engineering Expo at the University of Louisville Speed School of Engineering celebrates the many facets of the engineering profession. This annual event hosted by Speed School showcases undergraduate research, pre-engineering competitions and activities for younger students, guided tours, exhibits, and the cutting edge research facilities at UofL. E-Expo fosters an atmosphere of progress and competition in order to promote the exciting developments of the engineering profession to the public. University of Louisville undergraduate and graduate students compete in different divisions of research competitions for a total of $2,500 in awards. High school students travel to E-Expo from all over in order to compete in design competitions hosted by the local chapters of professional engineering societies. The Conn Center hosts the Mickey R. Wilhelm Solar-powered Flight competition.

Course Offerings
UofL offers renewable energy and related courses through the Speed School of Engineering, including:

- CHE 694: Energy Challenges, Chemical Engineering. An overview of challenges for renewable energy technologies, including history and theory, basic science and technological concepts underlying all of the renewable energy technologies, including basic concepts involved with thermodynamics of energy conversion and storage technologies, solid state physics concepts for materials, passive and active solar, solar fuels, energy storage, and biofuels. The students are required to design and demonstrate systems incorporating the concepts learned in the course.
- ME 570: Sustainable Energy Systems, Mechanical Engineering. Analysis and design of sustainable energy systems, and exploration of concepts such as carbon capture and sequestration for making traditional energy systems more environmentally acceptable.
- ECE 500: Renewable Energy, Electrical and Computer Engineering. This course explores renewable energy systems, including biomass, solar, wind, and hydro technologies, primarily for electrical power generation along with environmental and economic impacts. Use of power generation methods in home-based systems, interfacing with the national power grid, energy storage systems, and concepts of intelligent power grid technologies, e.g. Smart Grid, will also be explored as related to renewable energy technologies.