Use of sensible and latent condensation heat of an organic Rankine cycle in a multiple‐effect desalination system: A comparative study of novel energy integrations

Abstract

Summary This paper presents a comparative study of novel energy integrations between Multiple‐Effect Desalination (MED) and Organic Rankine Cycle (ORC) systems for the simultaneous production of desalinated water and electric power. Two new MED/ORC configurations are proposed, where part of the sensible and/or latent heat of condensation of the ORC is used to potentiate the generation of steam in the last effect of the MED, taking advantage of the temperature levels present in the MED. A simulator of the proposals was developed and validated with experimental results reported in the literature. These configurations are compared energetically with the MED and ORC systems working individually and against another previously proposed configuration, also considering the impact of the integrations on the heat transfer area required by the systems. The results show a decrease in the thermal energy requirements for the activation of the MED system with the new integrations. The energy requirements of the MED are reduced by 28% when integrated into the first effect with the ORC evaporator. The utilization of the sensible heat of condensation of the ORC in configuration 3 did not present a considerable energy decrease compared to configuration 2, due to the limited sensible heat available for its recovery, of approximately 22 kW. The usage of the latent heat of condensation of the ORC in configuration 4 implies that increasing the condensation temperature and pressure of the ORC, decreases its efficiency by 1.8% and increasing the energy required by 221 kW provides the two services simultaneously.