Sustainable Water Solutions Final Report
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| Category | Student Contributions |
|---|---|
| Abstract | The purpose of this project was to develop a sustainable rainwater harvesting and solar water heating system to assist in or completely fulfill the hot water needs of the in-patient ward at Tenwek Hospital. The system was designed with sustainability in mind; minimal environmental impact, low maintenance, and low operating cost. The following diagram summarizes the operation of the proposed system.A first-flush system is included to allow the user to purge the system of debris before storage. To satisfy the daily hot water demand, water is pumped up once a day to an elevated storage tank by 10am, which is then gravity fed through an array of active open-loop solar water heaters, heating the water to an average temperature of 45°C. A constant flow regulator is installed at the outlet of the elevated storage tank. The heated water is then stored in a thermally insulated storage tank to be used and delivered as needed. This water could be used to supplement the existing electric water heating system, or as the primary water heating system. Initially, based on correspondence with hospital personnel, the rainwater harvesting system was designed to supply 4,000 liters of water approximately 95 percent of the time. To meet this need, water needs to be collected off of the inpatient ward, maternity ward, and hostel. Four 24,000 liter Kentanks placed behind the hostel are needed to ensure that enough water is stored to compensate for a lack of water during dry periods. A 4,000L elevated tank is needed to feed the daily demand through the heaters, as well as a 4,000L thermally-insulated storage tank. The total cost for the system, including all tanks, gutters, routing, and solar heaters, comes out to approximately $41,000. Taken over a five year period, this equates to roughly 0.6 cents per liter. With this baseline design established, an investigation was undertaken to determine the most cost-effective design based on the available building collection areas. In summation, the customer will need to choose the daily supply that best fits their needs, and then refer to the report for the details of the system (number of solar collectors, expanded capacity, number of tanks, etc.). A webpage on the GlobalHub site also includes simulation programs and additional information to assist in specific system design. This can be found at |
| Contributor | Robert S Janesheski |
| Sponsored By | ESW - Engineers for a Sustainable World and Purdue University |
| Cite this work | Researchers should cite this work as follows: |