Saline Water Temperature Research Articles

Efficient Design of Desalination System Using Photovoltaic and Packed Bed Systems

This work presents a new way to realize continuous operation of a solar desalination system to produce fresh water using solar energy for a dual purpose. Here, solar energy is used directly as heat energy through solar radiation incident on an inverse V-shape still cover during sunlight hours. At the same time, the solar energy can be converted through a photovoltaic (PV) array into electric energy, which is stored in the battery system during sunlight hours. To realize the continuity of still operation daily and overnight, the batteries are discharged during the night at a suitable rate to feed an electric heater. The electric heater is designed to generate the required heat for desalination during the night. The heat is equivalent to that which can be absorbed during the day and that gives the temperature difference to gain evaporation and fresh water (productivity). This modified still is provided with a packed bed layer installed in the bottom of the basin to assist the system during the day and at night, i.e., this modified still will be more efficient. The quantity of heat energy during the night is adjusted to give a saline water temperature in the range that occurs in the actual solar still during sunlight hours. The performance of all components of the present still are discussed. The use of PV and packed bed systems means higher efficiency than the passive still, as the modified still produces large quantities of fresh water in August for a saline water depth of 0.01 m by using glass wool insulation 0.05 m thick and glass spheres as a packed bed with 0.0213 m bed length.

Heat and Mass Transfer From a Streaming Hot Saline Water in an Enclosure Partitioned by an Active Baffle

Equations describing heat and mass exchanges in a closed cavity with hot saline water streaming on its base and partitioned by an externally cooled flat heat exchanger are numerically solved. The results obtained show that an increase of inlet saline water temperature or mass flow rate increases the heat and mass transfer between evaporation and condensation surfaces. Furthermore, external cooling of the condensation surface contributes significantly to the increase of these exchanges. Our theoretical analysis is in reasonably good agreement with experimental results published in the literature for the practical heat exchange fluxes encountered in solar stills.