20100241401 | Solar collector electronic freeze protection system, with differential circulation control of pump and automatic freeze protection - An automatic and electronic freeze protection system for solar energy collector systems. The system includes a solar collector for collecting solar energy in the form of heat, a circulation pump operated by a DC power source (typically a small photovoltaic module), a storage tank, an ac current connection to provide freeze protection at times when no sun is available, and various valves and piping to complete. Sensors are provided at both the storage tank and the solar collector to monitor the temperature of the water and also the temperature of the collector (more specifically, the temperature of the fluid in the collector). Whenever the fluid in the collector approaches its freeze point, the electronic freeze protection will use AC or battery power to energize the DC circulation pump, thereby circulating water from the storage tank to and through all components of the system. When the temperature of the collector (the temperature of the fluid in the collector) rises to a predetermined point and freezing is no longer imminent or possible, the electronic freeze protection will shut off the circulation pump. This process will repeat as often as is necessary to protect the collector and system components that are exposed to freezing temperatures. The primary difference between our current invention and existing systems is that there is no electronic freeze protection device available for DC-solar systems. In addition, we have combined existing DC differential control with electronic freeze protection for a truly unique and extremely useful improvement. Differential control of the circulation pump will increase efficiency of the system, thereby increasing total solar gain. Finally, and uniquely, this invention includes fault protection in the event of an open or shorted sensor at the collector. In the event of a fault, the present invention will energize the circulation pump, thereby preventing freezing and making the system fail-safe. The invention is unique by three means: combination of electronic freeze protection AND differential control in a single unit, automatic backup with battery and ac power, and fault protection for fail-safe operation. | 09-23-2010 |