This concept proposes to recreate solar thermal power plant technology at reduced scale and lower cost for applications in remote locations.
A solar thermal power plant is typically large (several megawatts), consisting of rows of sun tracking parabolic trough mirrors, vast piping networks, and steam turbines adapted from the conventional power plant. The inventors retain the basic concept, but have redesigned the components to operate at the kilowatt scale, using lower cost materials available through global supply chains and fabricated through simple manufacturing facilities.
The team’s key innovation has been the replacement of the steam turbine plant with a specially designed Organic Rankine Cycle (ORC) generator that can operate at lower temperatures with their low cost parabolic trough collectors. Because parts for an ORC are virtually non-existent at scales below 100kW, the team use modified components from existing HVAC applications, almost like running a chiller in reverse operation where heat from the solar collectors drives the scroll to produce electricity. This innovation is made possible by tandem scroll operation to achieve efficient volumetric expansion ratios, and control systems to operate the ORC at a load that balances its output with the incoming solar energy.
The team’s vision is to provide clinics and schools in developing countries with cogeneration Solar ORC energy systems that are reliable, affordable, non-polluting, and locally produced.
About the Finalist Team:
Team STG
The STG team formed to meet the energy needs of underserved remote communities with a novel low-cost solar thermal co-generation technology. Formerly known as the Solar Turbine Group, STG was founded as a 501(c)(3) corporation in 2006 by a core team of MIT-trained engineers working with volunteers, industry consultants and advisors with experience in developing world markets, alongside partner engineers and technicians in southern Africa.
Matt Orosz supplied the vision behind STG’s solar thermal Organic Rankine Cycle (ORC) approach. He holds a Master of Science and a Master of Engineering degree from MIT and a bachelor’s degree from Dartmouth College. A former Peace Corps volunteer in Lesotho (2000-02), Matt began prototyping Solar ORC equipment at MIT in 2004. He was soon joined by fellow MIT graduates Amy Mueller, Elizabeth Wayman, and Bryan Urban in a sustained research, development and testing program that included yearlong trials in Lesotho supported by the World Bank in 2006-2007. As STG President and the project’s lead engineer, Matt has led the implementation of the World Bank sponsored work in Lesotho, and he continues to provide inspiration and leadership to the group, coordinating the construction of Solar ORC pilot plants in Lesotho and St. Petersburg, Fla. to advance STG’s goals. Alongside this work, Matt is currently pursuing a doctorate in environmental engineering at MIT in energy systems integration. In 2009, Matt was a Fulbright Scholar in South Africa.
Amy Mueller, who is also currently a doctoral candidate at MIT, is focused on the electrical and control subsystems of STG’s technology. Amy earned her master’s degree in engineering from MIT in 2003 after completing her bachelor’s of science in 2002. In addition to her work on the electrical and control subsystems, she acts as the STG treasurer and the technology liaison for current partners, including the Sopogy Corporation, Eckerd College, and the Government of Lesotho.
Elizabeth Wayman, holds a Master of Science and Bachelor of Science from MIT. She has worked at SunPower and various clean tech startups, and has applied her extensive experience in renewable energy systems to thermodynamics modeling and design of prototypes in Lesotho. Bryan Urban, holds a Master of Science Degree from MIT and a Bachelor of Science from Cornell. As a project manager at the Fraunhofer Center for Sustainable Energy Systems, Brian has contributed his wide-ranging expertise in engineering, business, and entrepreneurship to the group. He has led market, customer, and government case studies for STG in Lesotho, and he has participated in formulation of a business plan for STG’s product in southern Africa.