Abstract
Applications of the 2 degrees of freedom control which has two different stages, the first stage to decide the control aims and the second stage to carry out the actual control, are studied for air conditioning devices. At first a packaged air-conditioner is studied as an example mainly for the first stage where its parameter is automatically adapted to various control conditions in order to keen its operation stable. This method can be used in addition to the conventional PID or other controllers. Next an absorption chiller using a multi-input fuzzy controller based on the 2 degrees of freedom control is proposed in order to comprehensively achieve diverse aims like conserving energy and better reacting to load changes on the first stage. On the second stage, wellknown characteristics about the heat source are mainly used for fuzzy inference. Experimental results confirm that the proposed method surpasses conventional PID control.
