| 摘要 |
<p>An apparatus and method for controlling a multi-compressor refrigeration system. The controller is designed to maintain a target temperature in a specified area. It achieves this goal by selecting compressor configurations which will maintain a target pressure on the common compressor suction line directing refrigerant into the compressors. As part of the process, the controller first establishes a record of the load handling capabilities of all useable configurations of the compressors. Then, periodically, it detects the current temperature and line pressure; selects a preferred configuration of compressors in accordance with a predetermined algorithmic function of the target pressure, the current line pressure, and the record of the load handling capabilities; and activates the preferred configuration if different from the currently active configuration. At at least one preselected time during the operation of an active compressor configuration the controller updates the record of load handling capabilities. This is done, in accordance with a predetermined algorithm, when the expected rate of change of the line pressure (determined by the record of load handling capabilities) does not match the actual rate of change while the active compressor configuration has been in use. The controller can also periodically float the target pressure by increasing the target pressure if the measured temperature is lower than the target temperature, and decreasing the target pressure if the measured temperature is higher than the target temperature. Additional features of the invention include the use of a nighttime target temperature, which is greater than the normal target temperature, and the provision for special actions to be taken when the system is in defrost.</p> |
