Solar distillation

Abstract

Malta lacks many natural resources and it is a pity that we have disregarded completely that we have mostly in abundance, that is solar energy. The importance and potential of solar energy utilisation cannot be overemphasised and we should strive so that in the future at least 30% of our energy needs should be supplied from solar sources (as has been suggested). Solar energy is by far a most attractive energy source for the Maltese islands, since, apart from the fact that is non-polluting, the amount of energy which is available for conversion is several orders of magnitude greater than all present needs. Furthermore, we must not forget how badly we were hit by the fuel crisis since we depended totally from foreign countries for our fuel supplies. We know that all countries can utilise solar energy without depending on each other. The only dependence would be on the sum itself. Up to a few years ago the only way we were using solar energy was by solar evaporation of salt brines to obtain the salts. Lately, we have seen the introduction of a few solar heaters on certain roof tops. However, due the initial capital costs little progress has been achieved. Hence, in order that me may start to enjoy utilising clean energy sources which is not in our doorstep but in our home (free of charge) we must put a greater effort in our work at least to lower the initial capital costs for solar appliances. Certainly, a most advantageous study for Malta would be the set up of a solar desalination plant. We know how scarce water is especially during the summer seasons and solar distillation would assist us to produce more fresh water especially when it is needed most. It is also worthwhile to note that a solar distillation plant would gather fresh water from rainfall due to the catchment area provided. In my project, after the historical background has been discussed, a study of a design of a solar still shall be carried out for local conditions. Because of the type of design, in which we have a double layer of glass with water passing in between, the study shall concentrate mostly on the effect of absorption of solar energy by the cover glass and the rate at which condensate is produced. Thus, a prediction on the performance of the still shall be completed after the thermal characteristics and various design features have been dealt with.