From ESWStanford
CEE 177S/277S: Design for a Sustainable World, Winter 2010
Project: Solar-Powered Refrigeration for rural Tanzanian communities
*Applications are up. See below.*
CEE 177S/277S Design for Sustainability is a student-led course organized by Engineers for a Sustainable World (ESW). This year we have partnered with Dissigno, a San Francisco based for-profit company whose efforts support small entrepreneurs in Tanzania. Students in the class will design, prototype and test a solar thermal-powered absorption refrigerator intended to generate ice in rural, off-grid communities. Over the summer, select fellows from the class will travel to Tanzania. Partnering with Dissigno and local entrepreneurs, they will attempt to establish a profitable refrigeration business using technologies developed in the course.
Info Session
When: Wednesday Novemeber 4
Where: Y2E2 first floor
What: Information about the solar refrigeration project. Hear about the operations of our partner, Dissigno, in Tanzania from Dissigno's president, Gary Zieff. Learn about the details of the refrigeration project from project leader Chris Tsoufakis and course TA Scott White. Refreshments will be served.
Application
Applications are due December 2, 11:59 pm.
Here is the link: [Application Link]
What is solar thermal absorption refrigeration?
We will be creating a refrigerator capable of making large amounts of ice without electricity. Absorption refrigerators use heat instead of electricity to pump heat from a cooling cabinet to the outside, lowering the temperature of the cabinet’s contents. The process starts at the solar collector, which uses radiation from the sun to heat the working fluid, ammonia. As a result, it becomes a hot, high pressure gas. The ammonia is then transferred to the condenser, which lowers the temperature of the fluid at a constant pressure, turning it into a liquid. From there it is fed into the cooling tank, and the pressure is reduced. The drop in pressure causes the ammonia to evaporate and retrace its route back to the solar collector. This evaporation process takes heat with it, thus cooling the contents cabinet and making ice.
Motivation
Refrigeration technology reduces post-harvest losses, reduces food waste, and lowers the risk of food-born illnesses. Many communities in Tanzania lack access to the electricity grid. As a result, residents cannot take advantage of technologies essential for economic growth, including refrigeration. A solar-powered refrigeration unit will enable the generation of ice without electricity. Dissigno and the class will provide the technology to enable entrepreneurs to set up businesses selling ice in these communities. Such technology will not only enable these entrepreneurs to make a living, but also spur the growth of other businesses that take advantage of this new commodity, and improve the lives of families that struggle to gather enough food to eat.
