In this active, closed-loop system, incoming potable water is routed to the solar storage tank, but never into the collectors. A water and anti-freeze mixture circulates from the collectors through a coil of pipe in the solar tank, and then is pumped back through the collectors. The potable water is warmed by heat transfer through contact with the pipe. In most climates, a 5SO/50 propylene glycol and water mixture will keep collectors from freezing. These systems require an expansion tank and a few other auxiliary components for filling, venting, and maintaining the system. A definite advantage to antifreeze systems is that the collectors can be mounted anywhere. These systems are pretty much the only choice in very cold climates. When there is not enough energy for sun, an electrical or gas back up element will be automatically switched on by controller.

Features:
- Simple Installation, No Maintenance, Effective operation
- Easy Retrofitting To Existing systems
- Suitable for single and multiple solar heating Application systems.
- Preferred option for extremely cold areas and questionable water quality.
- Incoming potable water is routed to the solar storage tank.
- Porcelain Enemal or SUS316 stainless steel Storage Tank With Electrical or Gas Backup.
- Double-walled Copper Coil heater in storage tank prevent contamination of household water.

System Running Principle: