A thin membrane heat-pipe solar collector was designed and constructed to allow heat from solar radiation to be collected at a relatively high efficiency while keeping the capital cost low. A theoretical model incorporating a set of heat balance equations was developed to analyse heat transfer processes occurring in separate regions of the collector, i.e., the top cover, absorber and condenser/manifold areas, and examine their relationship. The thermal performance of the collector was investigated using the theoretical model. The modelling predictions were validated using the experimental data from a referred source. The. test efficiency was found to be in the range 40-70%, which is a bitter lower than the values predicted by modelling. The factors influencing these results were investigated. (C) 2004 Elsevier Ltd. All rights reserved.