Our study is related to an experimental work and modelling of a simple solar still (SSS), green house type, asymmetrical and a hybrid system of a solar still connected to a heat pump (SSSHP). Simple solar stills have in general very low efficiency and our study aims in improving that incorporation by heat pump. This will increase vapor condensation, improve efficiency and consequently the output per m(2) of still surface area. Data obtained from our experimental research are used to determine convective and evaporative heat transfer coefficients such as the experimental and theoretical efficiencies. The nom of the hybrid system is HSSHP. Daily output increased from 2 l/m(2) for the SSS up to 12 l/m(2) for the HSSHP and average efficiency increased from 20% to 80%. (C) 2009 Elsevier B.V. All rights reserved.