Quantification of Thermal Energy Transport in Membrane Distillation

Membrane Distillation (MD) is an attractive technology for treatment of high salinity waters (e.g. waste brines, produced water, saline ground waters) that can take advantage of low grade heat or solar thermal energy, reducing its operational costs. However, the MD process performance (i.e. flux, water recovery, and thermal efficiency) which is governed by the heat transfer to the membrane-water interface cannot be directly quantified in experimental systems. Past efforts to quantify energy transport to the water-membrane interface have used thermal transport models that rely on bulk temperature and flow rate measurements, and the inaccuracies from this approach have led to high uncertainty in translating process performance from the bench to commercial scale. Herein, we present a novel approach that leverages our fundamental understanding of vapor transport to quantify thermal energy transport and significantly reduce the uncertainty in estimated MD process performance. We further present methods for direct surface temperature measurement in MD that allow for direct quantification of heat transport and process performance.