4th Steam Practice Test

Active solar heating relies on moving the heat transfer fluid with powered equipment, such as a circulating pump (and sometimes a fan in air-based setups). The energy from the sun heats the liquid in the collectors, and the pump then pushes that warmed fluid through pipes to a storage tank or directly to the load. This forced circulation is what defines an active system and separates it from passive systems that rely on natural convection to move fluid. So while direct sunlight provides the energy, it’s the mechanical equipment that actually moves the fluid to transfer that heat where it’s needed.