Brugia Malayi - Clark Science Center - Smith College

Solar Collector
Rohini Ray and Ansha Zaman
With the emerging need for renewable energy, this project is aimed at designing an efficient water heater that utilizes the solar
heat. The collector is based on the ideas of maximized contact with the solar ray, minimized loss through insulation and high
heat storage capacity consists of a double walled acrylic cylinder within the inner cylinder runs a coiled copper tube (high heat
capacity), through which the water will be passed. The transparent acrylic should prevent filtration of the solar rays, allowing a
greater incidence of the waves on the copper coils, while also giving the collector durability. We also plan to improve our design
by coating the copper coils, in the next set of collectors, with a partial absorber- black chrome which should enable the copper
and hence the water to get hotter faster. The area surrounding the coil is to be filled either with a pressurized gas- He, CO2, N2
or vacuum. The vacuum filled chamber between the two cylinders insulates the unit by restricting heat loss through conduction
and convection. Placing o-rings in end-cap groves should also counteract heat loss from the system. We inserted a foam (that has
a glass transition temperature of above 100 degrees Celsius) bed at the base to hold the copper tubing in place, which should also
act as an additional source of insulation.
The commercially available solar heaters have losses in efficiency due to lack of direct contact between the medium that gets
heated by the sun, and the water to be heated, and as they are rectangular, thereby reducing exposure to the sun’s rays. Our design
attempts to avoid these two inefficiencies.
During the testing process the different gasses will be filled into the collectors and a constant pressure will be maintained
using the pressure gauges. The efficiency of the collector under each gas and vacuum will be recorded by measuring the
temperature difference between the incoming water and the outgoing water. The gas with the highest change in temperature
will then be used, and we can empirically analyze the productivity of this model vis-à-vis others. (Supported by the Schultz
Foundation)
Advisor: Nathanael Fortune
2012
157