Mathematical Approach to Improve the Thermoeconomics of a Humidification Dehumidification Solar Desalination System

Abstract

Water desalination presents a need to address the growing water-energy nexus. In this work, a literature survey is carried out, along an application of a mathematical model is presented to enhance the freshwater productivity rate of a solar-assisted humidification-dehumidification (HDH) type of desalination system. The prime novelty of this work is to recover the waste heat by reusing the feedwater at the exit of the condenser in the brackish water storage tank and to carry out the analysis of its effectiveness in terms of the system’s yearly thermoeconomics. The developed mathematical model for each of the components of the plant is solved through an iterative procedure. In a parametric study, the influence of mass flow rates (MFRs) of inlet air, saline water, feedwater, and air temperature on the freshwater productivity is shown with and without the waste heat recovery from the condensing coil. It is reported that the production rate of water is increased to a maximum of 15% by recovering the waste heat. Furthermore, yearly analysis has shown that the production rate of water is increased to a maximum of 16% for June in the location of Taxila, Pakistan. An analysis is also carried out on the economics of the proposed modification, which shows that the cost per litre of the desalinated water is reduced by ~13%. It is concluded that the water productivity of an HDH solar desalination plant can be significantly increased by recovering the waste heat from the condensing coil.

Sustainable water solutions:a Six Sigma approach to membrane-based filtration system design

“…Also made collaboration with industry partners, and organizations to share knowledge and innovation in sustainable water solutions. It is also recommended in the future to apply the six-sigma method on other filtration systems like humidification-dehumidification desalination (Tariq et al, 2018;Tariq et al, 2021) and compare the performance of both systems.…”

Thermodynamic and technoeconomic comparative justification of a waste heat recovery process with integration of multifluid and indirect evaporative cooler

“…Another application would be to integrate the conventional desalination units [53][54][55] with the M-power cycles. Another interesting simulation tool would be to evaluate the Mpower cycles using digital twin modelling [56][57][58][59][60][61][62].…”

Estado del arte. Métodos de desalinización de agua

“…Existen algunas variantes de este procedimiento que se emplea en varios métodos, pero en general consta de las siguientes etapas: humidificación de aire, que ingresa en condiciones ambientales y se humedece hasta el punto de saturación o cerca al mismo, una unidad de condensación, donde se enfría el aire y se condensa la humedad en un intercambiador donde se precalienta la corriente de agua salina que ingresa y una etapa de calentamiento externo de la corriente de entrada hasta alcanzar entre 60-70 • C [83,84,85,86,87,88]. La fuente de energía en la etapa de calentamiento puede ser un concentrador solar, un sistema de resistencias eléctricas o uno basado en la combustión de diésel, gas, etc.…”