Step 1. The evacuated tubes absorb sunlight and convert it into usable heat.

Step 2. The heat inside the evacuated tubes is transferred up into the insulated black box at the top of the tubes which contains is a copper heat exchanger.

Step 3. An electronic controller measures the temperature of the solar collector and the water in the bottom of the storage tank. If the collector is hotter, meaning there is heat available, the controller supplies power to a circulation pump which pushes water through the collector heat exchanger and back to the storage tank.

Step 4. Throughout the day the circulation pump switches on and off gradually heating up the water in the tank.