This short article describes the operation of OPEN LOOP CIRCULATION TYPE DOMESTIC WATER-HEATERS.
Your Solar Water-Heater
Your home is equipped with an “open loop solar water heating system.” This system is composed of the collector panel, a large capacity storage tank and a DC circulation pump. The pump is powered either by a photo-voltaic (PV) panel or AC power.
When the Sun is Shining…
The PV panel makes electricity that powers the pump. The pump draws the water out of the bottom of the storage tank, circulates it through the collector panels and returns it to the tank. The more direct the sunlight (striking the panels at right angles), the better the systems works.
Here in Sarasota, we attempt to orient the collector panels facing south at an angle of 27 degrees. The rule of thumb is to set the degree of tilt equal to the degree of latitude. This creates the optimum annual harvest for a fixed array.
When the Sun isn’t Shining…
The system doesn’t work. Electric elements in the storage tank will heat the water used at night or during cloudy hours. On foul weather days, the solar system may act as a pre-heater, raising the ambient temperature of the water a few degrees.
Are required on your part. When it is beneficial for water to circulate through the collectors, the pump will operate. When it isn’t, it won’t.