Human-Powered Potable Water Still
Version HPPW4.1

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Note:  Teams entering this contest are expected to read and understood all of the rules and procedures given here.  Furthermore, all teams are expected to check and follow all of the “Questions and Answers” which will be posted on the linked web page approximately weekly as the contest year proceeds.  Q&A can not only clarify but can sometimes modify rules when appropriate.   Teams will be responsible at the contest for meeting any limits set within the answer to a question. 

The Q&A are the organizing committee’s attempt to make this a responsive and fair competition for everyone.  Any questions asked of the committee will be posted on the web page along with the answer for everyone to see.  “Private” questions will not be answered.  To avoid inadvertent last-minute changes in contest rules, no questions will be accepted after February 16, 2007.

Visit the Student Professional Development Conferences website for information on contest locations.

“Water, water everywhere
And not a drop to drink.”                   
Coleridge, “The Ryme of the Ancient Mariner”

Coleridge’s ancient mariner had much in common with many people marooned on rooftops during the recent hurricanes—surrounded by water, they were dying of dehydration and desperate for at least a minimum of clean potable water.  But in New Orleans the city water system was down and the water people were surrounded by was either brackish or filled with both biological and chemical pollutants.  One of the ways of purifying some of it would have been to distill it.  However, electrical power was not available, solar energy was limited or not available, and filter systems, which could have been available, might not have removed all of the pollutants present.

One possible solution to this problem would be to make use of a human-powered still.  This could provide at least limited amounts of purified water, enough at least for drinking purposes in an emergency situation.  A major question to be answered, however, is whether or not using human work input to heat the water is a feasible approach.  Handbook values for the work output by a human are varied, but calculations based on this limited information, as well as thermodynamic properties and heat transfer considerations, seem to indicate that there is some reason for optimism on this point.  The purpose for this competition is to see if students can design and build a device which will heat water to reach boiling temperatures, and then to condense the steam generated to get potable water.

Such a “human-powered boiler” would have the following characteristics:

1. All significant energy input would come from a linkage or mechanism driven by human effort.
2. It should be small enough to be easily stored or transported for emergency use.
3. It should be easily assembled from its stored configuration