SOLAR ORC TECHNOLOGY FOR RURAL ELECTRIFICATION IN REMOTE AREAS
Time Period: 2007 - Now
The proposed technology is a small-scale distributed co-generation platform ("Solar ORC") that uses solar energy to produce electricity and thermal energy supplies renewably and affordably. The solar thermal design uses the heat from sunlight directly to drive a heat engine and to produce hot water (or cooling via an absorption-chiller type process). By using a cogeneration scheme to recover some fraction of the "waste" heat, a higher fraction of the sun's energy is captured and turned into useful energy.
These microgenerator systems are built using widely available parts including steel, plumbing supplies, HVAC or automotive parts. Specialty components (the aluminum reflective sheeting and refrigerant working fluid) are generally available as well, though the microgenerator design can be updated to use alternative materials in areas where they are extremely costly or difficult to source. The goal is a microgenerator design that can be constructed almost anywhere, unlike silicon-based photovoltaic cells which rely upon high-tech clean rooms for manufacturability.
Initial prototype systems were designed to produce between 600W and 1kW of electricity along with ~10kW of hot water. In such a configuration, a 24 square-meter array of parabolic mirrors can produce up to 600L of hot water during a sunny summer day (approximately half as much on a sunny winter day due to the shorter day). Current designs provide 3-4kW of electricity along with hundreds of gallons of hot water per day, optimized to provide energy for off-grid schools, clinics, or community centers where both electricity and hot water are in high demand.
The STG team has been working on the development of this technology since 2004. Several generations of prototypes have been constructed and installed in Cambridge, Massachusetts (USA); Bethel, Phamong (Lesotho), Matjotjo Village, Berea District (Lesotho), and St. Petersburg, Florida (USA).