Membrane distillation (MD) is a process emerging commercially which offers potential as a low cost, low energy desalination process. However single pass recovery in MD is typically limited by thermodynamic constraints to less than 10% thus leading to the need to increase recirculation to achieve practical water recoveries, which costs electricity and produces more greenhouse gas emissions. This work reports on heat and mass transfer modelling and experimental results for a novel MD design, known as the MD heat exchanger (MDHX), which facilitates the addition and removal of heat into the MD hot and cold channels respectively. The modelling and experimental results showed that the MDHX system greatly enhances the single pass recovery at low flow rates. At the proposed experimental conditions, the MDHX process was demonstrated experimentally to increase single pass water recovery from 2% to 14%. This promises to reduce the electrical pumping costs to less than 0.01 kWh for every m(3) of water produced. Much higher recoveries are theoretically possible. The novel MDHX concept and module therefore offer new opportunities for heat sourcing or improved system performance for desalination and liquids processing over conventional MD. (C) 2012 Elsevier B.V. All rights reserved.