Design of environmentally conscious absorption cooling systems via multi-objective optimization and life cycle assessment

In this paper, a systematic method based on mathematical programming is proposed for the design of environmentally conscious absorption cooling systems. The approach presented relies on the development of a multi-objective formulation that simultaneously accounts for the minimization of cost and environmental impact at the design stage. The latter criterion is measured by the Eco-indicator 99 methodology, which follows the principles of life cycle assessment (LCA). The design task is formulated as a bi-criteria nonlinear programming (NLP) problem, the solution of which is defined by a set of Pareto points that represent the optimal trade-off between the economic and environmental concerns considered in the analysis. These Pareto solutions can be obtained via standard techniques for multi-objective optimization. The main advantage of this approach is that it offers a set of alternative options for system design rather than a single solution. From these alternatives, the decision-maker can choose the best one according to his/her preferences and the applicable legislation. The capabilities of the proposed method are illustrated in a case study problem that addresses the design of a typical absorption cooling system.