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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]

Abstract This paper describes the experimental method to establish a salinity gradient in a MgCl 2 solar pond (SGSP) at Bundoora East campus of Royal Melbourne Information of Technology (RMIT) University, Melbourne, Australia. The pond was instructed in 2001, with a 15 m 2 surface area. This experiment involves using saturated brine to establish the lower thermal storage (or convective) zone (LCZ) as well as the middle insulating layer in which the salinity decreases with height. This non-convective zone (NCZ) is proctored from mixings caused by the wind and the destabilizing effects of diurnal variation of the ambient temperature by an upper convicting layer (UCZ). In this top layer (UCZ) both the temperature and salinity are uniform. These properties increase with depth in the (NCZ). Density and temperature usually assume their maximum values at the interface between the NCZ and the lower convective zone (LCZ). Both these properties y are usually constant in the (LCZ).In order to set up the salinity gradient using an injection filling technic introduced by Zangrando technique (1980). In this method, the pond is first filled to half the depth of the planned gradient zone with highly concentrated salt water. Next, fresh water, or salt water of a low concentration, is injected horizontally into the brine through a diffuser. The novelty for this paper is investigation redistribution method experimentally using simple technic to find the required volume of injected fresh water. [ABSTRACT FROM AUTHOR]

Abstract This paper describes the practical experience gained from setting up salinity gradient in a MgCl solar pond at Bundoora East campus of Royal Melbourne Institute of Technology (RMIT) University, Melbourne, Australia. This involves using saturated brine to establish the lower thermal storage (or convective) zone (LCZ) as well as the middle insulating layer in which the salinity decreases with height. This non-convective zone (NCZ) is protected from mixings caused by the wind and the destabilising effects of diurnal variation of the ambient temperature by an upper convicting layer (UCZ). In this top layer (UCZ) both the temperature and salinity are uniform. These properties increase with depth in the (NCZ). Density and temperature usually assume their maximum values at the interface between the NCZ and the lower convective zone (LCZ). Both these properties are usually constant in the (LCZ). [ABSTRACT FROM AUTHOR]