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In the direct contact membrane distillation (DCMD) system, the temperature polarization due to boundary layer formation limits the system performance. This study presents the experimental results and heat transfer analysis of a DCMD module coupled with a salinity gradient solar pond (SGSP) under three different flow channel configurations. In the first case, the feed and permeate channels were both empty, while in the next two cases, the feed and permeate channels were filled with a porous spacer material. Two different spacer geometries are examined: 1.5 mm thick with a filament angle of 65°, and 2 mm thick with a filament angle of 90°. The study considers only the heat transfer due to conduction by replacing the hydrophobic membrane normally used in a DCMD module with a thin polypropylene sheet so that no mass transfer can occur between the feed and permeate channels. The Reynolds number for all three configurations was found to be between 1000 and 2000, indicating the flow regime was laminar. The flow rate through both the feed and permeate sides was the same, and experiments were conducted for flow rates of 5 L/min and 3 L/min. It has been found that the highest overall heat transfer coefficient was obtained with the spacer of 2 mm thickness and filament angle of 90°. [ABSTRACT FROM AUTHOR]

Abstract This research is investigating the possibility of using heat stored in solar ponds for salt drying. At present, Pyramid Salts, a salt producing company located in the north of Victoria, Australia, use electric heaters to heat ambient air from around 20 °C to around 70 °C in their salt crystallizers for salt drying. This research paper aims to develop a solar PV driven heat pump coupled with a solar pond to supply necessary hot air. According to the collected data solar pond performance in Pyramid Hill indicates that heat will be available at the bottom of the pond between 35 °C to 50 °C (winter to summer). Coupling the salinity gradient solar pond with the heat pump is the novelty of this research paper. The heat pump's evaporation boosts from ambient temperature to available solar pond heat (40 °C) and above 24/7 all year around. As a result, the amount of electrical energy saving in this project has been estimated to be about 1 GWh per year. In this work, the preliminary data on the developments of salinity, temperature, and turbidity profiles will be considered and discussed. [ABSTRACT FROM AUTHOR]