• Renewable Energy Technology
  • Powering Rural Health and Education
  • Technology Transfer and Training
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SOLAR ORC: How it works
IN THIS SCHEME, YOU CAN SEE THE MAIN COMPONENTS OF THE SYSTEM AND HOW THEY WORK TOGETHER.
  • SUNLIGHT
    falls on the trackin collector an is concentrated 40-fold
  • Solar Thermal Energy
    from the concentrated sunlight is absorbed in a heat transfer fluid (HTF) circulating inside of a heat collection element (HCE - a selectively coated pipe with glass insulation) in the focus of the parabolic through collectors. The temperature of the HTF reaches up to 160ºC
  • ELECTRICITY
    is produced in the power block by thermodynamic processes known as the organic Rankine Cycle (ORC). Usin refrigerant 245 fa, the ORC absorbs heat from the HTF in the vaporizer at high pressure, while the pressure is lowered in the condenser using air fans. Between the two, an expander-generator extracts work from the hot vapor while a pump repressurizes the cold condensate.
  • Storage
    A quartzite pebble bed tank is used in the HTF loop between the collectors and ORC, both as a thermal battery and to moderate temperature changes, providing a stable thermal source for the power block.
  • Cool air
    is circulated through a heat exchanger in the ORC called the condenser. Because water is often too precious for cooling, our system uses the ambient air to provide the necessary heat sink and temperature potential for the ORC.

solar_orc_2

SPECIFICATIONS:

THERMAL INPUT
  • Direct Sunlight
    • 800-1000 W/m2, peak
    • 400-600 W/m2, nominal
  • 50-70% thermal collector efficiency
COLLECTOR THERMAL OUTPUT
  • 650 W/m2 peak thermal output
  • 150º C max. temperature
  • 70 m2 array = 40 kW thermal, nominal
ORC HEAT AND POWER OUTPUTS
  • 3 kW electrical / 23 kW thermal (co-generation mode)
    • up to 15% thermal-electric efficiency
    • 2-10% solar-electric efficiency
  • 48V DC output (battery charging)
  • 220 V AC inverter
  • 1000 L hot water / day

"I would like to see local groups building this technology and putting it in place instead of diesel generators."

- MATT OROSZ -

"As engineers, we're all excited about making things work. Once I was on the ground, the social and economic components were really brought home."

- AMY MUELLER -


OUR HISTORY
SINCE EARLY 2000’s STG MEMBERS HAVE BEEN DOING THE DIFFERENCE IN PEOPLE’S LIVES
  • 2013
  • OUTREACH TO OTHER COUNTRIES

    Ongoing work has focused on continued technology development, monitoring of field installations in Lesotho, and promotion of local technology development in Lesotho as well as partner outreach to other countries where solar energy stands to have a major impact such as India.

    January 1, 2013
  • 2006
  • AWARD AND MORE FIELD TRIALS

    In May of 2006, the team traveled to Washington D.C. to participate in the 2006 Development Marketplace Competition, focused on Water Supply, Sanitation, and Energy. The project was awarded one of that year's grants for work in the Energy sector, supporting implementation of further field trials in Lesotho. Three founding members of STG spent almost twelve months during 2006-07 living and working in Bethel, Lesotho (Mohales Hoek District) implementing this grant.

    May 1, 2006
  • SECOND PROTOTYPE IN LESOTHO

    Funds from two IDEAS Awards and several fellowships from the MIT Public Service Center fueled development and deployment of a second field prototype in Lesotho during January 2006. Work began on simplification of the design to comply with locally-available supplies, such as air conditioning parts, plumbing supplies, and standard steel, aluminum, and hardware.

    January 1, 2006
  • 2005
  • FIRST FIELD TRIALS IN LESOTHO

    Several iterations of collection systems were prototyped before the first field trials in Lesotho during January 2005.

    January 1, 2005
  • 2004
  • ENGAGEMENT INCREASES

    Other undergraduate and graduate students became involved through Amy Smith's D-Lab (Development, Design, Dissemination), the Fall 2004.

    October 1, 2004
  • 2000
  • THE BEGINNING

    During his Peace Corps duty in Lesotho (2000-02), STG President Matt Orosz experienced first-hand what it is like to live in a rural mountain village with no electricity or running water. Impressed by the simplicity of a locally-constructed parabolic solar bread cooker, Matt began to experiment with ideas for converting solar energy into other useful forms, like hot water and electricity. He returned to the United States to pursue a graduate degree in engineering at MIT where these ideas were slowly formed into designs, experiments, and prototype technologies.

    January 1, 2000
OUR TEAM
The team behind STG consists of a core group of MIT-trained engineers joined by a group of dedicated students, industry consultants and advisors with experience in developing world markets. A team of talented engineers in Lesotho is continuing work on STG’s first field prototypes.

Matt Orosz, PhD

President, Director (USA)

Matt is the Lead Engineer and Project Coordinator for all of STG’s work.

Amy Mueller, PhD

Treasurer, Director (USA)

Amy works primarily on the electrical and electronic control systems, contributing to work in Lesotho since 2005 and to the development of the Eckerd field site system

Elizabeth Wayman

Secretary, Director (USA, 2006-2013)

Libby has recently stepped down from the Board of Directors to pursue an opportunity with the U.S. Department of Energy – we wish her the best of luck with this endeavor!

Bryan Urban

Director (USA)

Bryan designed and led STG’s first market, customer, and government study for Lesotho in 2007 and continues to provide insight into project, partner and market development.

Sylvain Quoilin, PhD

Technology Development and Field Evaluation (Belgium)

Sylvain’s role on STG’s team is ORC system improvements, modeling, and advanced technology development, along with contributing to work testing pilot systems deployed in Lesotho.

OUR PROJECTS
HERE YOU CAN FIND A LIST OF YOUR MAIN PROJECTS.

Pilot Health Clinic

Eckerd College

Bethel High-School

Village of Ha Teboho

Technology Transfer and Training

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