When we say circulation, we mean the circulation of domestic hot water. In solar water heaters, the hot water goes to the boiler, following the rule of physics (gravity), which says that the hot mass of water is lighter and therefore tends to rise above the cold mass of water which is heavier.
So the hot water goes to the boiler, which for this reason is higher than the collectors. This movement of water takes place throughout the day.

HOW THE HURRY UP TRAFFIC SYSTEM WORKS

In forced circulation systems, the boiler is not exposed above the collector, but inside, usually in the engine room, and of course lower than the level of the collectors. Thus it is not possible for the hot water of the collectors to flow naturally due to the gravity to the boiler but it is assisted by a pump (forced circulation)
When and how long the pump will work is decided by an automatic controller, which is programmed to compare temperatures and other conditions.
The boiler is usually triple energy, ie, in addition to solar energy, it has an electrical resistor and an alternator from a boiler or heat pump or other energy sources.

A system of accelerated circulation is chosen when our requirements for hot water can not, due to quantity, be met by a solar water heater. Accelerated circulation systems are also used for heating as an auxiliary source.

ADVANTAGES

Higher efficiency compared to the conventional solar water heater, due to smaller losses.
Continuous and 24 hour supply of hot water for use due to the combination of the operation of the controller (boiler) and the storage system (boiler) which is of large capacity and very low losses because it has very good insulation and is located in a protected area.
Best aesthetic result since the collectors are almost “invisible” while the container is placed in the engine room.

A system of accelerated circulation is chosen when our requirements for hot water can not, due to quantity, be met by a solar water heater. Accelerated circulation systems are also used for heating as an auxiliary source.

ADVANTAGES

Higher efficiency compared to the conventional solar water heater, due to smaller losses.
Continuous and 24 hour supply of hot water for use due to the combination of the operation of the controller (boiler) and the storage system (boiler) which is of large capacity and very low losses because it has very good insulation and is located in a protected area.
Best aesthetic result since the collectors are almost “invisible” while the container is placed in the engine room.