| 摘要 |
<p>A method and control system for operating a refrigeration unit to permit random loading and unloading sequences of multiple compressors and unloaders. The random loading and unloading sequences of the two circuits of compressors and unloaders is performed by a microprocessor. A random sequence is selected at start-up and the selected sequence loads the compressors to full load, where upon another random sequence is selected to unload the compressors. The compressors are also loaded in response to the water temperature leaving the chiller. The leaving water temperature is compensated for by a return water temperature which determines the temperature drop through the heat exchanger. The temperature drop is divided by the number of active stages to determine the drop/stage, which is an indication of how the leaving water temperature will change when a capacity stage is either added or subtracted.</p> |
