The system is an offshoot of the $1K solar water heating systems with some useful new design features.
|The twinwall glazing is a very nice look.|
|The 300 ft of PEX is recoiled into a two layer coil for|
more water exposure to each coil.
Nathan also offers details and source code for making an open source Arduino based differential controller.
|Arduino based differential controller.|
All the details on Nathan's website....
For more on the $1K solar water heater and dozens of other DIY solar water heaters...