This work presents a multi-period and multi-objective optimization based on mathematical programming of solar assisted absorption cooling systems. Seven solar collector models combined with a gas fired heater and an absorption cooling cycle are considered.
The optimization task is formulated as a multi-objective multi-period mixed-integer nonlinear programming (MINLP) problem that accounts for the minimization of the total cost of the cooling system and the associated environmental impact. The environmental performance is measured following the Life Cycle Assessment (LCA) principles.
The capabilities of the proposed method are illustrated in a case study that addresses the design of a solar assisted ammonia-water absorption cooling system using the weather conditions of Tarragona (Spain).
Air conditioning and refrigeration have a significant contribution to the total energy consumption. The growing demand for air conditioning and refrigeration has caused a significant increase in the consumption of primary energy resources, to the end that it currently threatens the stability of electricity grids.
Thus, a change in the energy structure should be made, promoting energy efficient technologies and renewable energies. A more sustainable concept, known as solar assisted refrigeration, is based on the use of absorption cooling cycles driven by thermal energy provided by solar collectors.
The use of solar energy for cooling applications has a high potential to replace partially conventional cooling systems, given the fact that the cooling demand matches the availability of solar irradiation. These technologies use renewable energy sources, thus decreasing the associated environmental impact. However, their cost is still higher compared to conventional cooling systems (i.e. , vapor compression cooling system).
The objective of this work is to provide a quantitative decision support tool for the optimal design of solar assisted absorption cycles. The model presented optimizes the operating and structural decisions of the absorption cycle taking into account simultaneously its environmental and economic performance. The environmental performance is measured based on the Eco-indicator 99, which follows the life cycle assessment (LCA) methodology.
Authors: Berhane H. Gebreslassie, Mélanie Jimenez, Gonzalo Guillén-Gosálbez, Laureano Jiménez and Dieter Boer