Integration of Renewable Energy with Industrial Absorption Refrigeration Systems: Systematic Design and Operation with Technical, Economic, and Environmental Objectives

Abstract

This paper presents a new methodology for the energy integration of systems that require refrigeration. It considers the integration between process streams as well as that between the heat from process stream excess, solar energy, fossil fuels, and biofuels to run the stripper required by the absorption refrigeration (AR) needed. The proposed methodology consists of two stages: the first one identifies the energy targets, while the second one uses a new mathematical programming model to solve a multiobjective optimization mixed-integer linear programming (MILP) problem, allowing one to determine the minimum cost as well as the minimum greenhouse gas emissions (GHGE) to satisfy the utility requirements identified in the first stage. The proposed model considers the optimal selection of different types of solar collectors, and since the solar radiation depends on the season of the year, the model also accounts for the best combination of fossil and biofuels to complement the energy required for the AR. The proposed methodology is very useful to identify the scenario required to implement the use of clean energies in the refrigeration process. Three problems are presented to show the applicability of the proposed methodology, which does not exhibit numerical complications; these results show that process integration helps to get a given reduction in the GHGE economically attractive involving the use of clean energies, besides identifying the required tax credit to get economic and environmentally efficient cooling systems. In addition, because of the availability of the solar radiation, the solar collectors must be integrated with different types of energy, depending on the season of the year.

Synthesis of integrated absorption refrigeration systems involving economic and environmental objectives and quantifying social benefits

“…The next two examples have been previously addressed by Tora and El-Halwagi [52], Ponce-Ortega et al [53] and El-Halwagi [68].…”

“…As can be seen in the economic objective function of this work, it considers the capital and operational costs for the heat exchanger units, which were excluded by Ponce-Ortega et al [53]. To determine the capital cost for the PTSC the following relationships are used in this work: Notice that the expression of the capital cost for the solar collectors is a nonlinear function, which is divided in three parts where each segment represents a linear function (see Fig.…”

“…And it requires re-write the equations inside the disjunctions in terms of the binary variables and the disaggregated continuous variables, ; cb˛B; ct˛T (53) where Heating Power b is the heating power for the biofuel b and Avail Max b;t is the maximum amount of the biofuel b available in the period t.…”

“…In addition, Tora and El-Halwagi [52] proposed a systematic approach based on the pinch technology for the energy integration of systems that require refrigeration including different sources of energies, and Ponce-Ortega et al [53] introduced a sequential formulation based on targets for solving this problem, where the capital costs of the heat exchanger units are not considered. Nonetheless, these methodologies have not considered simultaneously the overall refrigeration system with the configuration synthesis of the heat exchange network including the transfer of heat from the hot process streams to the absorption refrigeration system.…”

Automated targeting model for synthesis of heat exchanger network with utility systems

“…Rubio-Castro et al [54] proposed a MINLP formulation for the optimal synthesis of re-circulating cooling water systems with associated HEN. Ponce-Ortega et al [55] presented a mathematical programming based approach to address the problem of a multiple objectives optimisation of absorption refrigeration (AR) cycles that are integrated with HEN. Meanwhile, Lira-Barragán et al [56] presented an MILP model to extend the above work [55] in order to incorporates sustainability criteria into consideration.…”