The interest of using solar powered membrane distillation systems for desalination is growing worldwide due to the membrane distillation (MD) attractive features. This study experimentally investigates utilization of direct contact membrane distillation (DCMD) coupled to a salt-gradient solar pond (SGSP) for sustainable freshwater production and reduction of brine footprint on the environment. A model for heat and mass flux in the DCMD module and a thermal model for an SGSP are developed and coupled to evaluate the feasibility of freshwater production. Experiments are conducted at RMIT University renewable energy laboratory using SGSP wall heat exchanger. The feed stream of 1.3% salinity is heated up by the wall heat exchanger and circulated through MD module then injected back to an evaporation pond. Also, a heat recovery system (Heat Exchanger) is used to back up heat from the outlet brine stream of DCMD and use it as preheating for inlet feed stream flow. Results are compared and shown that if the flow is laminar, the connecting DCMD module to the SGSP could induce marked concentration and temperature polarisation phenomena that reduce fluxes. Therefor turbulence has to be created in the feed stream to reduce polarisations and the brine is recirculated after passing through the heat exchanger to reduce the environmental footprint.
Khaled Nakoa, RMIT University, Australia
Abhijit Date, RMIT University, Australia
Aliakbar Akbarzadeh, RMIT University, Australia
Stream: Energy: Renewable Energy and Environmental Solutions
This paper is part of the NACSEE2014 Conference Proceedings (View)
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