An active solar system uses electric pumps and controls to actively circulate heat transfer fluid between solar collectors and storage tanks. Unlike passive systems, active solar systems can operate regardless of component positioning and provide better performance in cooler climates. They require electricity to function but offer superior flexibility and efficiency in various conditions.
Technical Details
Active systems employ differential temperature controllers that automatically activate pumps when collector temperature exceeds storage tank temperature by 10 to 20 degrees Fahrenheit. Pump flow rates typically range from 1 to 3 gallons per minute per 100 square feet of collector area. System pressure ratings generally reach 100 to 150 PSI, allowing collectors to be positioned below storage tanks.
Applications and Practical Significance
Active solar systems suit climates with winter freezing, variable sun exposure, and commercial applications requiring high hot water volumes. They can achieve 60 to 80 percent energy savings for water heating. The added cost of pumps, controllers, and sensors (typically 25 to 40 percent more than passive systems) is justified by improved performance and year-round reliability in diverse climates.