Multi-objective optimization of absorption refrigeration systems involving renewable energy

This work presents a new methodology for the synthesis of absorption refrigeration systems integrated with different types of fossil energies (i.e., coal, oil, natural gas, etc) and renewable energies (i.e., waste-heat recovery, biomass, solar energy) to operate the stripper required by these heat-powered systems to release the vapor at the higher pressure. Since in a given location, the available biomass and solar energy depend on the season of the year, this work proposes an appropriate multi-period approach to satisfy the energy requirements by the process year-round. To properly solve the addressed problem, this work presents a two stage methodology considering social and environment aspects besides the economic performance. The first stage identifies the energy targets while the second stage uses a new multi-objective mathematical programming model to determine the minimum cost, minimum greenhouse gas emissions and the maximum social benefit that satisfies the energy target identified in the first stage. It is noteworthy that the main novelty of this work is the incorporation of social criteria, and particularly the consideration of the potential jobs generated to satisfy the energy target identified in the first stage. The proposed model considers the optimal selection of different types of solar collectors. The application of this methodology to a case study in Mexico shows that it is possible to reduce the greenhouse gas emissions at attractive costs obtaining additional social benefits through the generation of jobs in rural areas when a combination of different biofuels, fossil fuels and a solar collector is used to run the absorption refrigeration system.