SOLAR CIRCULATION PUMPS
The solar circulation pump is the heart of our solar systems.
When the temperature of the fluid in the solar collector becomes 6 degrees higher than that in the water to be heated the solar controller starts the solar pump.

The solar pump circulates the warmed water so the heat is transferred into the cylinder or heat exchanger.
The pumps used are subjected to high temperatures and are frequently in the stop and start mode.

Many of our domestic systems use a solar PV powered pump and controller and provide a 100% solar solution with no connection to mains electricity. Larger and more complex installations require larger pumps and a 240 volt supply.

As a rough guide the flow rate required in a system, 0.1- 0.2 litres per tube per minute is required.
On larger installations we commonly install two pumps per system with stagered start up temperature differentials, ensuring that when extra heat is available it is transferred at a faster flow rate.

CIRCULATING PUMPS
Centrifugal-type circulating pumps are most commonly used in solar water-heating systems. Centrifugal pumps generally have low power consumption and low maintenance and are highly reliable. The bodies are typically made with cast iron, bronze, or stainless steel. For closed loop systems lower cost, cast iron circulating pumps are adequate. For open-loop systems, circulating a replenishing supply of water, a bronze circulating pump is necessary. Stainless steel pumps are used in swimming pools and other applications where chemicals are present.

Once it is determined that the pump is to operate in a closed loop, open loop, or other particular environment, the solar system head and flow requirements are used to select the appropriate pump. Head is the pressure the pump must develop in order to create desired flow through the system. The overall pressure a pump must create is determined by the height the water must be lifted and the frictional resistance of the pipe. Static head is pressure resulting from the vertical height and corresponding weight of the column of fluid in a system. The higher a pump must lift the fluid against gravity, the greater the static head it must develop. Dynamic head includes the frictional resistance of the fluid flowing through the pipe and fittings in the system. The pressure a pump must develop to overcome dynamic head varies with the size and length of the pipe, number of fittings and bends, and the flow rate and viscosity of the fluid.
Circulating pumps are typically categorized for low, medium, or high head applications. Low head applications have 3 to 10 feet (0.9-3 m) of head; medium head applications, 10 to 20 feet (3-6 m) of head; and high head applications, over 20 feet of head.

WATER CIRCULATING PUMP
used for circulating the flow of the antifreeze between the solar panel and the storage tank.