solar

Sustainable Solar Sanitation System

Georgia Institute of Technology

This team is addressing the issue of sanitation in developing countries through the development of a dry latrine system that provides sustainable, affordable, and safe treatment of human waste using the sun’s energy. While some dry (waterless) latrines are already being marketed, a system has yet to be developed that effectively inactivates Ascaris cysts, which present a major health risk to people in communities with inadequate sanitation facilities.

The team is working to create a latrine that captures both solid and liquid wastes, provides space to store solid waste for a specified time, exposes it to concentrated sunlight in order to deactivate and kill all pathogenic organisms, and then uses the deactivated waste as fertilizer in a revenue-generating microenterprise. The team has fielded several prototypes in remote areas of Bolivia and, using lessons learned from the field, is currently working to refine the design to make it more robust, effective and profitable.

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University of California - Berkeley, 2007 - $38,210

Most solar water heating systems on the market today use advanced materials that are affordable for wealthy clients in developed countries. Our team aims to change that trend by developing a low-cost solar water heater for use in low-income Guatemalan households. The successful implementation of solar water heaters in Guatemala could improve local health and hygiene, promote economic growth, and lessen the impact on the environment at the same time. The team's initial design, which is made to provide hot water for bathing/ showering, consists of three basic components: a heat-collecting surface (absorber), a water bladder, and an insulating material. Two prototypes have been built, and two of the team members have traveled to Guatemala to work with partner NGO Appropriate Infrastructure Development Group (AIDG) in order to gain first-hand information on local conditions and materials. The team is now looking to finalize the design of the heater, explore partnerships with local organizations that can provide financing services that will allow people to buy the heater, conduct surveys of potential users in Guatemala to gauge their energy needs and test the heater in the  field. Ultimately, the team will enable local businesses in developing countries to build and sell the heater to local households, creating local job opportunities while realizing the benefits of sustainable technology enterprises.

The team is now called Calsolagua. From their website:

"The CalSolAgua Team has developed an innovative solar water heating system to address the need for clean and inexpensive energy sources for households. It is fully capable of addressing the hot water needs for bathing and laundry: one of highest energy needs facing households. Our team developed a solar water heater that retails for one quarter of the price of competing water tank heaters through detailed design work and three generations of prototyping. With an expected mass manufactured retail price of only $150, our product reduces household energy costs and provides health benefits to those households currently relying on fossil fuel generated electricity for water heating."

Summer 2009 update: The team developed three solar water heater prototypes and has been partnering with AIDG, another Sustainable Vision grantee that launched a venture called Xela Teco. The Berkeley team hopes to license their solar water heater technology to Xela Teco and other potential partners committed to sustainable development. The team is continuing to work on their prototype, which is being tested on 5 installations (4 houses and the local AIDG intern house).  The team has made several trips to Guatemala to install systems, monitor them, and collect user feedback. In addition, the team has made two trips to conduct focus groups and other market analysis. Users demonstrated a willingness to adapt their showering habits to maximize the energy savings of the current solar water heater prototype, which provides ample hot water during the day. However, the team is continuing to refine its design to improve overnight heat storage, a customer preference identified through market analysis. Following the successful field-testing of the team's new prototype, the team will file a patent to support the pursuit of larger market opportunities.