Optimal control of single stage LiBr/water absorption chiller

Low-capacity refrigeration and space conditioning systems have increased significantly in the last years, increasing primary energy demand. For this reason, it is important to start implementing refrigeration and space conditioning system that can be driven by unconventional energy sources, such as a single stage lithium bromide absorption refrigeration chiller since it can be powered by a low grade heat source. Therefore, we establish an optimal control strategy to operate these systems. For the implementation of the optimum control a dynamic model to evaluate the system is developed and discretized and solved using the interior point optimization (IPOPT) solver. The cases studied where a step and a sinusoidal perturbation on the hot water inlet temperature. The results obtained are promising because, through the implementation of the optimal control strategy, the coefficient of performance (COP) of the refrigeration system was significantly improved, reducing operational cost and all this without affecting the cold water outlet temperature.