Recent Projects: Environmental and Sustainable Design
Bringing Back The Ice House
Team: Nii Tettey Addy, Matthew Heffley, Laura Kier, Akwugo Nnama, Lucas Sanford-Long, Richard Waitumbi
Sponsor: Craftsbury Outdoor Center
Advisor: Mark Laser
Craftsbury, an outdoor recreation center and athletic training facility that uses and teaches sustainable practices, wants a low-cost and energy efficient passive refrigeration system for a new walk-in cooler. We constructed an 8' x 12' x 8' ice house prototype to test two heat-exchange design alternatives. The first involved an aluminum sheet with fans on either side to provide forced convection across the sheet to cool the food-room air and warm the ice-room air. The second involved direct air exchange between the food and ice rooms using automated fans. Based on testing, we recommended the second system. Due to concerns of mold growth in a direct air-exchange system, we also recommended that the client test both systems under summer conditions. Compared to a commercial cooler of comparable size, the internal rate of return obtained from costs saved by the adoption of the ice house is more than twice Craftsbury's desired 6.5 percent rate of return.
Conversion Of Liquid Paint To Disposable Waste Product
Team: Isabelle Caffry, Emily Cummings, Alan Salas
Sponsor: Dartmouth Athletics Facilities
Advisor: Mark Laser
Dartmouth Athletics Facilities (DAF) repaints the lines on the grass and turf fields each week with latex paint. Washing the marking machines over a gravel pit generates 40-50 gallons of waste paint water per machine. Over time, water and paint sludge build up in the pit. Every two years the pit is dredged, allowed to dry, and replaced for approximately $3,000. The high cost and waiting time caused DAF to seek an alternative solution. Our design incorporates chemical, mechanical, and procedural changes. Washing the tank and immediately removing the water reduced wastewater to 7-8 gallons per washing. The wastewater is moved to a 60-gallon barrel, which is treated when full. Crushed moringa seeds are added to cause the paint to fall out of suspension. After 18 to 24 hours, psyllium husk powder is added to form a gel that prevents the paint particles from resuspending during water removal. The design removes up to 98 percent of the paint. The water can then be disposed down the storm drain. The solution can save $1,063 annually after an initial equipment cost of $204.