Experimental study of tray materials in a thermal desalination tower with controlled heat source

• A one-stage desalination system was built to study different tray materials.
• Five trays made of aluminum and stainless steel AISI 304 were tested.
• The aluminum tray yielded the highest production per energy input.
• The apparatus was adequate to study the performance of a desalination tower tray.

Solar thermal desalination systems can operate with a variety of heat sources, and one of them is solar radiation. In solar heated systems, due to the variation in the daily radiation values, the study of the thermal variables and parameters is complicated. In this work, a new one-stage desalination system with controlled heat source was constructed to study its performance as a function of different tray materials. The system consisted of a storage tank with an electrical resistance immersed in brackish water as the heat source, and a one-stage desalination unit with a replaceable metallic tray. Five trays made of aluminum and stainless steel AISI 304 (polished, chrome-plated, and non-polished) were tested. The results show the overall heat transfer coefficient for each tray in the heating phases (sensible heating and steady state operation) and in the cooling phase, when the electrical resistance is turned off. The aluminum tray yielded the highest production per energy input (0.406 mL/kJ). Measurements of the electrical conductivity were used to indicate the produced water quality. The apparatus developed was adequate to experimentally study the performance of a thermal desalination tower tray.