Anatomy of the pressure adjustment mode of the condenser of the small chiller

Anatomy of the pressure adjustment mode of the condenser of the small chiller

During the operation of a small chiller, changes in temperature will cause changes in condensing pressure. In particular, the high condensing pressure in summer will cause the power consumption of the compressor to continue to increase, resulting in a gradual decrease in the cooling capacity, and indirectly worsening the circulation of the low-temperature chiller. It is necessary to appropriately reduce the condensing pressure.

Then, in winter, the condensing pressure of the unit is too low, the throttle valve's hydraulic power is insufficient, and the high-pressure liquid pipe is constantly affected by heating factors. They will all reduce the capacity of the throttle valve, so it is necessary to control the condensing pressure of the low-temperature chiller. Therefore, it is imperative to control the condensing pressure throughout the year.

　　The pressure of the condenser can be controlled by adjusting the heat exchange capacity of the condenser. When the heat exchange of the condenser increases, the gas discharged from the compressor (scroll/piston) can be fully condensed, and the condensing pressure will gradually decrease; if the heat exchange performance of the condenser is weakened, the condensing pressure will continue to rise.

　　 Take an example: a water-cooled condenser can adjust the cooling water flow to control the condensing pressure. Install a regulating valve on the condenser cooling water outlet pipe. There are two modes of water volume control valve: one is a temperature type water volume control valve that uses the temperature of the condenser cooling water outlet to indirectly signal. It has a temperature sensor, which is inserted into the condensation outlet. When the water temperature increases, the valve opens; when the water temperature decreases, the valve closes. The other is a pressure-type water volume regulating valve that uses the condensing pressure to directly send a signal, and the pressure signal is derived from the condenser. When the condensing pressure gradually increases, the valve opens; when the condensing pressure decreases, the valve closes, thereby changing the condenser's cooling water flow.

There is also a special case: the water-cooled condenser adopts its own cooling tower cooling water circulation system. In order to prevent the condensation pressure from being too low, it can be adjusted by a water volume bypass valve, which makes part of the water from the condenser send to the cooling tower for cooling. One part returns to the bypass back inlet.

　　 For large low-temperature chiller units, if multiple cooling water pumps are used in parallel to supply water to the water condenser, the number of water pumps can also be changed according to the continuous change of condensing pressure to adjust the cooling water flow.