There are several types of solar water hearting systems. Passive ie. Batch, and Thermosyphon. Active systems using a pump to move the solar fluid Open, Closed Loop and Drain Back. Both the Batch system and the Thermosyphon the weight of the water in the storage vessel is stored on the roof adding a lot of extra roof load. The batch system is like a tank or several 4” tubes in and insulated box with a glass cover plate. Cheapest system available and the least heat collected. The Thermosyphon has the tank sitting above a flat plate collector(s) and the heat collected in the solar collector rises to the tank for storage.

With Active systems a pump powered by PV or plugged into an electrical solar controller is used. The pump forces the fluid through the solar collectors located on the roof taking the heat to a storage tank located in the garage.

Open systems are not used in this area and have water in the collectors. They may suffer freeze damage during cold weather.

Closed loop and drain back use a heat exchanger to transfer the solar collector fluid to the storage tank. The Drain back system uses water as the heat transfer fluid through the collectors and a small tank is used inline to store the water so the collectors can drain empty when the pump turns off.

Closed Loop with antifreeze system the collectors are always full and under pressure with an non-toxic antifreeze to keep them from freezing. It is circulated through the heat exchanger where it indirectly heats the water that is used for bathing, etc.

Q: “What does a ‘Net Zero home’ mean?”

A: “A net zero home is one that makes as much energy as it uses. We now have the components available to accomplish this on new homes and even existing homes can be retrofitted with this technology. Existing homes may not get all the way to net zero but a net 10 or 20% home would still be fantastic.”