LiBr absorption chillers, which use water as the refrigerant, are environmentally friendly, CFC-free, and operate with high stability. They are widely applied in large buildings and industrial cooling systems. However, many people may not realize that during the shutdown process of such units, there is a crucial procedure known as dilution operation. Though it may appear routine, it is directly related to whether the unit can operate safely and reliably over the long term.

What is Dilution Operation?

Dilution operation refers to the process of maintaining the solution pump and cooling water in operation for a period of time before shutting down the unit. This allows the temperature of the LiBr solution inside the system to gradually decrease while circulating the solution to dilute its concentration to a safe range, thereby preventing crystallization after shutdown.

In other words, dilution operation is like performing essential adjustments before the unit “rests,” ensuring that the LiBr solution is stabilized in a safe condition.

Purpose of Dilution Operation

The core purpose of dilution operation is to ensure the safety and stability of the unit during shutdown. Specifically, it serves to:

Prevent crystallization: Reduce the solution concentration and avoid entering the crystallization zone when the temperature drops.

Ensure uniform distribution: Circulate the solution thoroughly inside the unit to eliminate localized high concentrations.

Extend service life: Minimize corrosion and blockage risks during downtime, thereby prolonging the unit’s lifespan.

Facilitate restart: Maintain a stable condition during shutdown, making it easier for the unit to return to normal operation during the next startup.

Although dilution operation is only one step in the shutdown procedure of a LiBr absorption chiller, its significance should not be underestimated. Each properly executed dilution cycle is essentially an insurance measure for the safety and longevity of the unit.