Seminar Series

Optimisation of solar desalination process


Alex Gorrie


ME Student in Mechanical Engineering

Time & Place

Fri, 22 Jul 2016 10:00:00 NZST in Kirkwood KH05


There is a global need for people to have reliable and secure access to potable water. In developing countries, water distribution infrastructure is often inadequate to meet demand. Implementation of a solar still within such contexts has the potential to increase potable water availability in a way that is situationally feasible. The current work is concerned with clarifying which technical and sociocultural factors are most important for optimising performance and community acceptance of a solar desalination still with particular focus for applications in nations in the South Pacific.

The influence of several environmental, design and operational factors on water productivity have been tested through an in vitro phase. This testing led to the formulation of a set of governing equations defining the system behaviour. The equations were based on fundamental heat transfer and thermodynamics principles.

There has been significant research undertaken in the field of solar desalination and a range of empirical and semi-empirical equations have been presented in the literature. The studies concerned with offering a thermodynamic basis for the equations are relatively few. No prior work was found to have integrated relative humidity as a system variable within the governing equations, although it has been acknowledged that the internal humidity of the still is below saturated. The current work addresses relative humidity as a significant system variable for the equation formulation and the models have good fit to the empirical data as a result.

The key factors of influence were extracted from the empirical and model-building phase and consolidated into a series of design implications for practitioners focussing on solar stills. These implications also considered the socio-cultural dimensions which are critical factors independent of the unit functionality. A framework was formulated which described a general new product design process tailored specifically for application in developing countries. This framework was then applied to the solar still case, thereby presenting an implementation pathway intended for practitioners in the field.