About Solar Hot Water

Watch our video demonstration and read our information below

Question: How does it work?

Answer: A picture is worth a thousand words… This diagram is the heart of a basic solar hot water system. Cold water is fed into the big tank on the left, and once heated by solar energy, exits into the existing hot water tank on the right. If the solar water is fully heated, the existing tank will just send it on into the house. If not, the existing tank will top it off with heat from gas or electricity.
The real magic happens in the fancy piece of machinery on the left. It has 2 pumps. One pump takes separate water from the small tank above to the solar panels, where it heats up in small copper tubes within the panel. Once through the panel, the water comes back down. The other pump brings water from the big solar tank on the left to meet the other water. They meet in the heat exchanger just to the left of the left tank, but never actually touch. On separate sides of flat metal plates, the hot water from the solar panels flows in the opposite direction of the cold water from the big solar tank. Heat is transferred over and over through this process, until the solar tank has all the hot water it needs!

Question: What’s the advantage of having a drainback system compared with any other kind of system?
Answer: In Oklahoma, the two proven systems that work well in our environment are both closed loop systems, using flat plate collectors. One is a pressurized system that relies on food-grade anti-freeze coolant, and the other is a drainback system, which relies on gravity and uses either water or that same coolant.
Our systems are technically referred to as active, indirect, low pressure, drainback, 2 tank solar hot water systems. What a mouthful! For short, we say drainback, and it is the only design EnergyWise has chosen to use.

Here are some of the advantages to drainback systems here in Oklahoma:

• Positive Freeze Protection
• Not dependent on electrical power or valve operation, just plain old gravity.
• The panels drain when not in use into a small drainback tank in a warmer environment.
• Uses water for heat transfer, which is an excellent thermal transfer fluid.
• Fluid stagnation is not a problem in hot weather. Propylene glycol can turn acidic and damage the system.
• Service calls are rare with properly installed drainback systems.

Question: There were a lot of ugly systems put on roofs in the 80’s. What about yours?
Answer: We totally agree! That’s why we have striven to enhance the aesthetic appeal of our solar hot water systems. All piping is hidden underneath panels, all panels are installed parallel to the roof(not at tilts), and the final product is an exact likeness of skylights.
If a roof is not the perfect angle, rather than tilt up the panels as in the days of old, we just add another panel and keep it close to the roof. Solar hot water panels are generally more forgiving than solar electric panels. The best placement is on either the south or west slope of your roof, with a low profile for limited visibility from the ground.