Background: If you've ever had the pleasure of using the bathroom at the Harris Teeter at 16th and Kalorama NW, you will be using a light-powered faucet. These solar sinks are provided by the Sloan Valve Company, a ubiquitous name in bathroom appliances.
How it works: The solar cell on top takes in energy from natural or artificial light and then charges a 6 volt lithium battery. The battery powers the sensor (infrared light beam) and solenoid valve. As you pass your hands by the sensor, it sends an electric current to the solenoid valve, which pulls back a damming rod and allows water to flow. When you take your hands away or after 3 minutes, the flow stops.
Cost: $500! The biggest costs are the solar cap ($123), solenoid valve ($137), transformer ($180), and sensor ($409).
Conclusion: If you want a touchless faucet and cut money on running water for your business, you've got some options.
-First, you could buy a normal sensor faucet. These are still $200-$500 and many come with batteries that need constant replacing (I'm going to include Touch2O in this group).
-Second, you could buy a foot pedal faucet. I used one while I lived in France and loved it. The down side is that these are not ADA compliant and are in the same price range as the normal sensor faucet.
Looks like the Sloan Solis faucet isn't all that bad for a commercial or government building.
Additional info: For more on solenoid valves, check out this high budget video.