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Solar Hot Water – Types of Systems
When you make the decision to use domestic solar hot water in your home, be sure to choose the system that will work best for your situation. Select a system that is simple so it results in lower operating costs, lower maintenance costs, fewer site visits, and lower energy consumption.
There are two standard types of solar hot water systems used in the United States: closed loop and drainback systems. Both use pumps and valves to control the circulation of the fluid throughout the system. They allow the system to run year round without the threat of freezing. Protecting the system from freezing is critical to the proper operation of any system.
The most common hot water system is the closed loop glycol system. This is a sealed unit where a propylene glycol mixture transports the heat within the system. The fluid is a mixture of antifreeze and water, which can be protected from freezing to -50°F. If overheated or stagnated, the fluid can go bad.
The second most widely used system is the drainback system. Fluid fills the collectors when the pump starts and drains the collectors when the pump stops. The drainback system is protected from freezing down to -20°F and overheating when there is no power.
Talk with a certified solar installer prior to making the decision to have a solar hot water system placed in your home. The North American Board of Certified Energy Practitioners (NABCEP) is the national certification organization for professional installers in the field of renewable energy. To locate a certified installer, visit NABCEP’s website at www.nabcep.org.
For more information, see: Introduction to Domestic Solar Hot Water Systems – CSU Extension
Updated Thursday, May 17, 2012