400L drain back solar panel water heater system

400L Drain Back Solar Water Heater System with 4pcs thermal solar panels, system water tank capacity 400liter hot water temperature more than 60℃ all year around. The drain back solar water heater system is a type of split solar water heating system which has advantage of anti freeze in winter and without over heating problem in summer. This solar hot water system no need glycol circulation, no need expansion vessel, no need pressure relief valve. It is simple and high efficient solar water heater .

The Reliable 400L Drain Back Solar Water Heater System is a highly dependable and efficient solar thermal solution designed for large - scale hot water needs. This system utilizes a drain - back mechanism, where the heat - transfer fluid drains back into a storage tank when the pump stops operating, preventing freezing and damage in cold weather. With a 400 - liter storage capacity, it can supply ample hot water for both residential and commercial applications, offering a sustainable and cost - effective alternative to traditional water heating methods.

Features

The feature of the drainback solar hot water system focus on drainage and return water function, which achieves automatic circulation of the heat transfer medium (usually water or antifreeze) through gravity. The system consists of solar collectors, a water storage tank, a circulation pump, and a control system, and its operating logic is as follows:

During the day, solar thermal panels abdorb solar heat, and transfer the heat to the storage tank through  pump circulation. At this period, the water temperature inside the collector can reach 150℃, while the storage tank water temperature of 60℃.

When the system detects that the collector temperature is lower than the storage tank temperature (e.g., at night or on cloudy days), or when the system pressure is abnormal, the solenoid valve automatically opens, draining the water from the collector into the storage tank. This process is gravity-driven, requiring no additional energy consumption, and avoids the risk of freezing in winter.

After drainage, only a small amount of air remains inside the collector, forming a natural insulation layer. Experimental data shows that in extreme environments of -20℃, the drainage system can maintain the internal temperature of the collector above 0℃, while traditional systems may experience pipe rupture due to medium freezing.

The Drainback solar water heating system can be customized to meet the daily hot water needs of normal households. For example, in Berlin, Germany, a 120㎡ house that has installed the Drainback solar system can save approximately 800 euros in electricity bills annually, and the payback period is shortened to 3 years.

Easy Installation and Maintenance: The system is designed for straightforward installation, with clear instructions and pre - assembled components. Its modular design allows for easy expansion or replacement of parts if necessary. Routine maintenance is minimal, mainly involving periodic checks of the pump, control system, and storage tank insulation.