Martin Klingensmith nnytech.net> writes: > The web page says that "you can hear the shop air compressor running..." > It also says "It makes about . 5 horsepower" so I'm not sure if that's a > misplaced "." > It seems unlikely that there is enough energy from the sun in that > pi*r^2 area to produce 5 HP. The dish seems to be 14 foot ~= 4 meter dia. so its area is about 12m^2 and it could in theory handle 12kW of power from the sun. But 5hp is about 3.5kWe and this implies about 30% efficiency which is a little on the high side imho, especially for something that boils water. The figure could be true if the power needed to pressurize the water tank was disregarded in the calculation. With what I assume to be a 2+hp compressor there remain only at most 1.5hp for output which is about 1.1kW or about 9% efficiency and is credible for something that boils water imho (if it is well designed). Peter -- http://www.piclist.com PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist