Submitted to: American Society of Mechanical Engineers
Publication Type: Proceedings
Publication Acceptance Date: 4/10/2001
Publication Date: 11/1/2001
Citation: Vick, B.D., Clark, R.N., Ling, J., Ling, S. 2001. Remote solar, wind, and hybrid solar/wind energy systems for purifying water. American Society of Mechanical Engineers. Solar Forum 2001. Washington, D.C. CDROM
Interpretive Summary: It has been reported that in developing countries water borne diseases lead to 5 to 10 million deaths and several billion illnesses annually. Ultraviolet (UV) irradiation of water is one of the most effective ways of purifying water and one of the least costly. A particular UV water purification unit has been approved by several health agencies for purifying water. However, the UV unit required utility supplied electricit to operate. Since most places which have unsafe water also do not have access to utility supplied electricity; USDA-ARS in cooperation with WTAMU-AEI developed a controller which enabled the UV unit to be powered by solar energy, wind energy, or a hybrid of the two. Not only was a controller developed which allowed various solar and wind energy devices via batteries to power the UV unit, but several improvements were made including: monitoring UV light intensity (to make sure the water was purified); including a pump instead of using a large storage tank gravity feed system for the dirty water; and dip switches which could allow different flow rates and time settings for different quantities of water to be pumped and purified. Five different solar, wind and solar/wind hybrid systems were tested with the UV water purification unit. Very few problems have been encountered over the two years of testing this system. A one kilowatt solar/wind hybrid system was shown to purify enough water for 4000 people during the entire year (assuming the wind and solar resource was similar to Bushland, TX) at a cost of about $1/person. The main benefits of this renewable energy powered UV water purification system are for villages in developing countries with unsafe drinking water, but this system could be used by anyone wishing to purify water in a remote location.
Technical Abstract: Solar energy, wind energy, and a combination of wind and solar energy have been used successfully to power an UV (ultraviolet) water purification system. The main reason for this success has been the design of the controllers which have been operating for almost two years with various wind and solar energy inputs. Five different solar and wind energy systems shave been tested so far and although these renewable energy systems have been used for water purification, graphs contained in the paper can be used to determine the feasibility of powering various other electrical loads. Combining a 100 Watt solar system with a 900 Watt wind turbine resulted in pumping and purifying enough water to satisfy the potable water requirements of 4000 people (16000 liters/day) at an estimated equipment cost of about $4660 (approximately $1/person).