What are the selection and precautions of air-cooled chiller units?
Introduction
Selection and precautions of air-cooled chiller units.
Details
I. Selection of air-cooled chiller units.
Generally speaking, when the nominal refrigerating capacity of a single unit is less than 116kw, scroll compressors are mainly selected; When the capacity of a single machine is between 116 kW and 700 kW, it is advisable to choose a screw machine. When the capacity of a single machine is between 700 kW and 1054 kW, it is advisable to choose a screw machine or centrifuge. When the capacity of a single machine is above 1785kw, a centrifuge should be selected. The number of units should be determined according to the size of the project and the change of air conditioning load. From the point of view of flexible adjustment and energy saving, it is better to have more sets; From the point of view of equipment investment, floor space and maintenance management, it is better to have fewer units. Generally, 2 ~ 8 sets are selected. For modular machines with double compressors, up to 8 machines can be connected in parallel, i.e. 1 main machine and 7 sub-machines; For the modular machines of 4 compressors, there can be at most 4 parallel machines, i.e. 1 main machine and 3 sub-machines.
II. The water pipeline installation. Same-journey and different-journey refer to the water flow directions of the main supply and return water pipes. When the two directions are the same, they are called the same journey; otherwise, they are different journeys.
III. Precautions for takeover. 1, the unit water system in and out of the water main, valves, filters and other components should adopt the same specifications. The connecting pipes between units are connected by damping throats. 2. The highest point of the water system must be equipped with a vent valve. There should be no excessive or urgent bends in the system direction. 3. When circulating water is running for the first time, please close the bypass valve on the water inlet and outlet side of the unit, install a temporary filter on the main road of the unit, turn on the water pump, and pre-clean the waterway until all impurities in the waterway system are removed. The unit can not be put into use until it is confirmed that there are no impurities in the water system. 4. When installing the inlet and outlet water temperature sensor, it is necessary to insert a blind pipe into the center of the pipeline to reduce the thermal resistance between the sensor and refrigerant water. 5. The modular units to be combined shall be of the same model. If there are more modules in parallel, the modules can be arranged in two rows. Please note: operation and maintenance space should be reserved on the side of the electric cabinet, and the distance between the two rows of modules should be at least 0.5m. 6. The external water pipe of the unit needs to be installed and supported.
IV. Installation precautions. 1. A water filter must be installed; 2. Test run is required to remove impurities in the pipeline; 3. The water flow switch shall be installed in the water outlet pipeline near the unit; 4. The filter of the unit should be cleaned regularly; 5. Ensure enough suction space to prevent short circuit circulation; 6. The base of the support plate of the unit shall be provided with damping plastic pads.
