ONTILITY and Alternate Energy Technologies (AET)

Alternate Energy Technologies (AET) provides pre-engineered residential and turnkey commercial solar thermal systems.

DBS Drainback System
The drainback system is a non pressurized, closed loop. The water is pumped up to the collector when the controller senses the temperature in the solar collector is greater than the temperature at the bottom of the storage tank. Once the tank reaches the desired temperature, the pump shuts off and the solar fluid (usually water) drains back into the reservoir leaving only air in the collector. This water never comes into contact with the potable water stored in the solar storage tank, and protects the system from freezing, overheating, and panel corrosion due to aggressive water.

The “DBS” system has an internal heat exchanger submerged inside the storage tank which heats the potable water. This innovative and efficient system has a single wall heat exchanger with only one pump, which makes this a crossover between the DB and DX systems.

Drainback System Features:

• Removes all water from the collectors, and their pipelines to ensure they never freeze when the system is not producing heat (drain mode.) Each time the pump turns off, the water in the collectors and piping, which are mounted at a slight angle, drains into the insulated reservoir.
• A sight glass attached to the reservoir tank indicates that the collectors have been completely drained.
• A differential Control senses temperature differences between water leaving the collector and the coldest water in the bottom of the storage tank. When the temperature of the water in the collector is hotter than the water in the tank, the differential control operates the circulating pump.
• Less moving parts allows for fewer maintenance concerns.

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