In LiBr absorption chillers, solenoid valves are small but indispensable key executive components. Their core function is to accurately control the on-off of pipelines through electrical signals, and their operation accuracy directly determines the refrigeration efficiency, stability and safety of the chiller. LiBr chillers rely on the thermal cycle of LiBr solution and refrigerant water in a vacuum environment to achieve refrigeration, with sensitive operating conditions and low fault tolerance. The function of solenoid valves is not a broad "on-off control", but focuses on two core scenarios: heat source control and safety protection. Only by analyzing in combination with the operating characteristics of the chiller can their irreplaceable value be reflected.

First, the precise control of heat source on-off and refrigeration capacity adjustment is the core guarantee for the normal start-stop and efficient operation of the chiller. The core of refrigeration in LiBr absorption chillers relies on external heat sources (such as steam, hot water, industrial waste heat) to drive the concentrated LiBr solution to heat and evaporate in the generator, generating refrigerant steam to complete the entire refrigeration cycle. Therefore, the on-off and flow control of the heat source directly determine the operating state of the chiller. As the "master switch" of the heat source pipeline, the solenoid valve has a response speed of milliseconds: when the chiller starts, the control system sends an electrical signal, and the electromagnetic coil generates suction to drive the valve core to open stably, allowing the heat source to enter the generator slowly to avoid sudden temperature rise and concentration fluctuation of the solution; when the chiller shuts down, the solenoid valve closes instantly after power failure, completely cutting off the heat source, preventing the solution from being over-concentrated and crystallized to block the pipeline, and reducing invalid energy waste.

Second, the linked safety protection is the "first line of defense" for the long-term stable operation of the chiller. LiBr chillers have strict requirements on operating conditions. When the chiller has abnormal conditions such as decreased vacuum degree, insufficient refrigerant water flow, high pressure of the generator, and risk of solution crystallization, the supporting sensors will immediately feed back signals to the control system, and the relevant solenoid valves will act quickly within milliseconds: when the vacuum degree decreases, the solenoid valve of the air extraction pipeline closes in time to prevent air from infiltrating and oxidizing the LiBr solution and reducing refrigeration efficiency; when the refrigerant water flow is insufficient, the solenoid valve of the heat source pipeline closes immediately to avoid overheating damage of the evaporator tube bundle due to lack of cooling medium; when there is a risk of solution crystallization, the heat source is cut off quickly to prevent the pipeline and pump body from being blocked by crystallization. After the chiller shuts down, the solenoid valves of key circuits remain closed, effectively preventing air and impurities from entering the chiller, protecting core components from corrosion, and maintaining the vacuum degree of the chiller to prepare for the next smooth start.

The precise heat source control and reliable safety protection of solenoid valves directly determine the safety, stability and efficiency of the chiller's operation. They are not only the key reason for becoming the core executive component of the chiller, but also an important support for ensuring the long-term stable operation of the chiller and giving full play to its energy-saving advantages.