Nick Glembotski, an engineering student at San Diego State, recently used our Current Sensor, Voltage Probe, and redesigned Surface Temperature Sensor (which can be used in air or water) to investigate whether the efficiency of solar panels can be improved by cooling the panels by spraying them with a mist. In his tests, the answer was yes, by several percent. He feels the extra cost of misting apparatus would pay for itself fairly quickly.
In this experiment, one panel had mist sprayed on it after a few seconds, and the other did not. The upper graph shows the temperature change when misting starts (bottom line). The bottom graph shows the increased current (top line) from the cooler solar panel.