A detailed investigation is carried out on the performance of an open-type absorption heat transformer (OAHT) that is coupled with either a single-effect or a multi-effect distillation system. In the analysis, the effects of the temperatures of the absorber, the condenser, the generator and the feed water of the OAHT on the overall performance are subject to examination. The whole cycle is optimized through a code developed in Engineering Equation Solver (EES). The results reveal the advantages and disadvantages of OAHTs in comparison with the commonly used absorption heat transformers (AHTs). It is observed that the OAHTs can attain higher coefficient of performance (COP) values than those of AHTs, leading to more distilled water production. It is found that for the OAHTs integrated with the single-effect distillation system, the COP and the produced distilled water are constant with increasing absorber or waste feed water temperatures. In contrast, for the multi-effect configuration, the COP rises with increasing absorber temperature while the distilled water production is reduced. On the other hand, when the system is fed with waste water at 140 degrees C the produced distilled water can be elevated to 12 kg/s while the COP reduces by over 40%. Moreover, it is discovered that the optimized temperatures of generator and condenser for both configurations are 60 and 40 degrees C, respectively. (C) 2015 Elsevier B.V. All rights reserved.