The application of feedforward control in a direct expansion (DX) air conditioning plant

A computerized feedforward controller for a DX air conditioning plant has been developed to avoid the use of problematic measurement of air conditions immediately downstream of a cooling coil for control action. The feedforward controller was based on a mathematical model for capacity control using the principle of energy conservation. A safety control procedure was also included as part of the control algorithms to ensure the safe operation of the plant. Experimental tests on the controllability of the controller confirmed that both control accuracy and sensitivity could be achieved. The control algorithms involved is expected to have wide application for controlling DX air conditioning systems.