Efficient, Low-Cost Solar Water Heaters
By Pelham Keahey
Utilizing the previous year’s King Creativity Research results in terms of material research we constructed a second solar heater that proved to be far more effective at heating water. The design called for a copper pipe snaked down a long metal plate inside an insulated, glass covered, box. The design gave us a large surface area in which heat could be collected and transferred to the pipe carrying the water. Insulation and black spray paint also greatly increased the efficiency of the heater.
The end result produced a heater which could heat roughly 8.4 gallons of water to 115 degrees Fahrenheit an hour given optimal weather conditions. This would not be sufficient to replace an electrical heater, but could supply enough water for several hot showers over the course of a day. However, in conjunction with an electrical heater the solar heater could reduce the amount of power needed for conventional heating, and eventually paying for itself.