ABSTRACT

A compressor-driven adsorption refrigeration system that uses graphite-BaCl₂ composite adsorbent/ammonia as a working pair has been investigated through dynamic optimization. The main purposes of this work were to obtain the optimal volume flow rate profile with the optimal cycle time and to improve the COP and SCP of this system simultaneously. A general dynamic multiobjective optimization mathematical model has been presented, and then shrinked to a single goal dynamic optimization problem by the weighted sum method. Because the cycle time was not specified, a normalized time variable was introduced and the cycle time was divided into a set of time stages of variable length. In order to solve this mathematical model, the iterative dynamic programming algorithm was adopted by a parallel program, and the effectiveness of this algorithm has also been verified. The optimal volume flow rate firstly keeps its maximum, and then drops to a relatively moderate value which rises slowly with time and reaches its minimum at the end of the cycle. As the weight of COP increases, the optimal volume flow rate control profile approaches the lower bounds and the optimal cycle time gradually gets longer.