Parametric investigation of modular configuration of multi-stage direct contact membrane distillation powered by waste heat of wind turbine

Abstract

In this study, various configurations involving parallel and series multi-stage direct contact membrane distillation (MSDCMD) were used to harness the waste heat of a wind turbine for freshwater production. A circulating fluid, which flowed around the wind turbine to cool its components, was heated as it flowed out of the wind turbine. The heat from the circulating fluid was transferred to seawater in a heat exchanger. The outlet seawater was utilized in parallel and series MSDCMD systems to retrieve freshwater and waste heat. Four configurations were proposed: Configuration 1 (a series MSDCMD with 1 × 15 modules), Configuration 2 (a parallel MSDCMD with 15 × 1 modules), Configuration 3 (a series–parallel MSDCMD with 3 × 5 modules), and Configuration 4 (a series–parallel MSDCMD with 5 × 3 modules). Configuration 1 achieved the highest permeate flux and water production, in the ranges of 13.4–70.5 kg/m2h and 1927–10,158 kg/h, respectively. However, Configuration 3 is the optimum configuration for achieving a higher gain output ratio (GOR) and evaporation efficiency (EE) and lower energy consumptions. In addition, the effects of the wind speed on the output parameters, that is, the permeate flux, water production, gain output ratio, evaporation efficiency, specific energy consumptions, and recovery ratio, were evaluated.