What does a hot water gravity circulation system rely on to move water through the pipes?

A hot water gravity circulation system operates by relying on the principle of differences in density, which is fundamentally linked to temperature changes in water. In this system, water is heated in a boiler, causing it to expand and become less dense than the cooler water in the return pipes. This difference in density creates a natural circulation effect: the lighter, heated water rises through the pipes, while the cooler, denser water sinks back down to be reheated.

This system does not depend on electrical pumps or external pressure to facilitate the movement of water. Instead, it utilizes the natural movement caused by the thermal expansion of water and the resultant differences in density. Gravity plays a role in the overall system, but it is the density difference that prompts the flow of water, making it crucial to how the system functions. Therefore, understanding how temperature affects water density is key to grasping the operation of hot water gravity circulation systems.