How it works:
The SOL-RELIANT™ solar water heating system is a closed loop active drainback* system circulating a mixture of glycol and distilled water. The pump circulates the fluid through a solar collector, where it collects heat from the sun and then flows back down to a coiled heat exchanger in the solar tank. The heated fluid raises the temperature of the water in the water heater.
One of the unique features of the Sol-Reliant system is that is uses a solar PV module to provide electricity to the pump, rather than sensors and a plug-in electric pump. The brighter the sun, the more energy sent to the pump and the faster the fluid flows. In weaker sunlight the pump slows down automatically, and stops completely when the sun goes down. The PV module control means less parts and zero household electricity usage, producing a very reliable, cost effective solution.
Before installing a solar water heating system, the cold water from your water source went directly to your
existing electric or gas water heater. Now it goes
to the bottom of the solar storage tank. The solar pre-heated water rises to the top of the tank due to stratification (hot water rises; cold water moves to the bottom). The solar pre-heated water then moves from the top of the solar storage tank to your auxiliary water heater whenever you turn on the hot water. The more the sun pre-heats the water, the less energy is required by your existing water heater.
The SOL-RELIANT™ system is fully automatic. The 12-volt DC pump is powered directly by the small photovoltaic module. The brighter the sun, the faster it pumps. The pump will effect some circulation if there is enough sun to cast a slight shadow. Thus, it is self-regulating. If there is no sun, the pump hasno power to operate, and the system will be in a state of rest, or "drained back." In the drained back state, the solar collector is empty, and the system is not pressurized. A small reservoir tube built into the bottom of the collector holds enough fluid to keep the pump primed during circulation. With the pump off, the operating fluid drains back into the reservoir tube by gravity. There is no possibility of freezing. In the event of a power outage, your solar system can still operate during relatively sunny conditions.
Open loop systems: Systems that circulate tap water directly through the solar collector.
Closed loop systems: Systems that circulate distilled water and/or glycol or antifreeze through the collector and a heat exchanger in the solar tank.
Active systems: use a pump to circulate fluid through the collector.
Passive systems: rely on water pressure and convection.
System Diagram:1. AE-56 high efficiancy thermafin collector (56 sq. ft.)
2. Low iron glass for maximum light transmission
3. Low point drain and fill valve
4. Warm fluid from solar collector
5. 36 watt photovoltaic (PV) module
6. PV module mounted to hide pipes (no visible plumbing!)
7. 12 Volt DC pump powered by PV module
8. High limit switch to prevent excessive temperatures
9. Manual on/off switch
10. Drain back reservoir attached just below bottom of collector
11. Heat transfer fluid--food grade propylene glycol
12. Insulation pad and wrat according to OSEIA standards
13. 12 volt DC electrical condutors
14. Flow meter measures gallons per minute
15. Temperature gauge, downstream mixing valve, and solar bypass valve to Brightway standards
16. Potable cold water in
17. Potable hot water out
18. 80 gallon solar tank with double wall heat exchanger
19. Two isolating ball valves, above and below pump