What type of tank is used to control air in modern heating system designs?

A diaphragm tank is essential in modern heating system designs to control air pressure and maintain the proper equilibrium in hydronic heating systems. This type of tank features a rubber diaphragm that separates the tank into two sections—one for water and the other for air. As the system heats up and water expands, the diaphragm flexes to accommodate this expansion, effectively managing pressure variations without allowing air to enter the system. This action ensures a consistent pressure, which helps to prevent issues such as water hammer and improves the system's efficiency.

While an expansion tank also serves a purpose in managing the effects of thermal expansion in a closed hydronic system, it is specifically designed to accommodate changes in the volume of water due to heating. A compression tank is not typically referenced in heating systems, as it is more relevant in gas storage or air compression contexts. The reservoir tank, on the other hand, is generally designed for storing fluids but does not actively manage air pressure in the same manner as a diaphragm tank. Therefore, the diaphragm tank stands out as the appropriate choice for controlling air in modern heating system designs.