|
Has anyone thought about building a two stage control for an electric water heater? My idea is to use contactors (with internal interlocks) to select between 240v and 120v (hot to hot or hot to neutral). An electronic temperature probe will be used to measure the actual temperature of the water and a flow sensor (could just be another temperature sensor on the outlet pipe) to determine when hot water is actually used.
A microcontroller can then be used to select between full power, 1/4 power, or no power. One way to control it would be:
* During night or when away, completely off.
* Otherwise, 1/4 power as necessary to maintain temperature.
* When in use, switch to full power.
The contactors will be mechanically interlocked as closing both would result in a short circuit. The existing thermostat, set to something like 140F (well above the intended setting), would be the safety control.
__________________
If America manages to eliminate obesity, we would save as much fuel as if every American were to stop driving for three days every year. To be slender like Tiffany Yep is to be a real hypermiler...
Allie Moore and I have a combined carbon footprint much smaller than that of one average American...
|