What is primarily used to circulate water in solar heating systems?

In solar heating systems, convection currents play a crucial role in circulating the water. When water is heated by the sun, it expands and becomes less dense. This reduction in density causes the heated water to rise, while cooler, denser water sinks. As a result, convection currents are established, creating a continuous flow of water through the system, thereby efficiently distributing heat throughout the solar collector or storage tank.

The process of convection is a fundamental principle of thermodynamics, making it an effective means of heat transfer in such systems. Unlike forced circulation systems that rely on pumps, many solar heating setups utilize the natural movement of water caused by temperature differences to operate. This not only enhances efficiency but can also reduce the need for additional energy input for pumps, aligning with the environmentally friendly goals of solar technology.