The expansion tank is an important part of the HVAC system. It contains the expansion of the system water in the heating system, and also plays a role in setting the pressure and replenishing the water for the system. It is generally made of steel plate, usually round or rectangular. Due to the thermal expansion and contraction of the water in the heating system, when the hot water heats up, the water volume in the system increases. When there is no place to hold the expansion of this part of the water, the water pressure in the heating system increases, which will affect the normal operation. The expansion tank contains the amount of water expansion of the system, which can reduce the water pressure fluctuation caused by the expansion of the system, and improve the safety and reliability of the system operation. When the system leaks or the system cools down for some reason, the water level of the expansion tank Drop to replenish water for the system. The expansion tank can also stabilize the pressure of the system and remove the air released by the water during heating.

Calculation of tank volume

V=αDtVa

In the formula, V-the effective volume of the expansion tank (that is, the volume equivalent to the height between the inspection pipe and the overflow pipe),L;

α-unit volume expansion coefficient of water, α = 0.0006;

Δt-consider that sufficient water capacity should be stored in the expansion tank regularly to compensate for the volume shrinkage during water cooling in the system, and the maximum fluctuation value of water temperature in the system is generally calculated from the water temperature of 20 ℃;

Va-water capacity in the system, L.