System analysis of membrane facilitated water generation from air humidity

• Membranes reduce the energy costs of atmospheric water generation by more than 50%. • We propose a model system to concentrate water vapor with membranes prior to cooling. • A system analysis is performed and ideal operational conditions determined. • A low pressure sweep allows energy efficiency even in the presence of leak-ages. • The quality of the condensed water improves by the use of membranes.

In this paper we have shown that the energy gain when using membrane technology in humidity harvesting is significant. The effect of membrane characteristics, temperature, humidity and leakage flows resembling realistic conditions has been evaluated. We have shown that when there is an inflow of non-condensable gases into the system, the energy balance can be improved significantly by non-trivial combinations of system pressure and a low-pressure recirculated sweep stream. It has been demonstrated that for a given input power twice the amount of freshwater can be produced with membranes, which is of superior quality. We expect that this enhancement can have a large impact on technologies using atmospheric water vapor as a source of drinking water and can be a large benefit, especially for remote areas. Future research is focused on experimental evaluation of the model results.