Above is a rough sketch of what our final reactor is going to look like. We will be using materials like solar panels, polycarbonate tubing, air pumps, and stainless steel in order to form a foundation for our design. The inside of the reactor will be a storage type area for materials as well as a place to keep our air pumps and wiring supplies. BACK of the envelope energy/water calculations for reactor For our Polycarbonate Tubing (ID 2.75 inches, OD 3 inches, L 4 feet):
Total Volume (one tube) = (pi)(radius^2)(height) --> (pi)(1.375 inch)^2*(48 inches) = 285 inches^3 of water volume per tube or 4.67L/tube when filled completely. For two tubes: maximum 9.34 L needed For four tubes: maximum 18.68 L needed For five tubes: maximum 23.35 L needed Water would need to be recycled or resupplied each complete algal growth cycle (about 10 to 14 days). For our Air Pumps (Max Power 5.5 W/pump, 15 L/air/minute for four outlets combined) Total Energy Demand w/Two Pumps on Max Power*: 5.5W/pump * 2 pumps = 11 W If 11 W is running 24 hours a day, then we would need 864000 J/day or 0.24 kWh/day. Using average Berkeley commercial electricity rates (14 cents/kWh), the total cost of our energy demand would be 0.0336 cents/day or $12.26/year if we are hooked up to the Berkeley electricity grid. Total Air Supplied: 15 L/min/pump * 2 pumps = 30 L/min / 8 outlets = 3.75 L air/min/outlet at max power*. *We will not be operating the pumps at max power during our experiments. These calculations are just to show the maximum energy demands for our reactor using two air pumps. Solar Panels: Using the above calculations, if we want to power the air pumps using solar energy completely, we need a solar panel output of greater than 11 W, probably around 15 W just to be safe. We will either have to use a battery system to supply power to the pumps at night or just use the outlet out in the courtyard. **These are not experimental numbers, just rough back of the envelope calculations from measurements made from the supplies already purchased. Updated data will be posted once prototype is tested.
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SUSTAINABLE ALGAE PHOTOBIOREACTORThe Sustainable Algae Photobioreactor Project is one of the various projects developed through the UC Berkeley division of Engineers for a Sustainable World (ESW). A special thanks to The Green Initiative Fund (TGIF) here at UC Berkeley for providing the grant to make this project possible.
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