Conceptual design and optimization of a small-scale dual power-desalination system based on the Stirling prime-mover

Producing the electric power using discrete systems as well as providing fresh water is essential for rural areas near to seawater that have no access to electricity and sweet water. In this regards, a small-scale production of fresh water and electricity was considered here. Due to the capability to be fueled with different sources of energy, Stirling engines are a suitable alternative for the discrete production of the electricity for rural areas. Accordingly, a conceptual design of a small-scale dual power-desalination system was presented here. Three configurations of small-scale desalination systems using a humidification-dehumidification system, HDH, was examined to be coupled to the GPU-3 Stirling engine and the waste thermal energy of this engine was delivered into the HDH system. The best operating parameters of the combined systems were found in a multi-objective optimization with the goal of maximization of the generated electricity and fresh water as well as minimizing the product cost, simultaneously. Among three optimized configurations, the best one was introduced using analytical hierarchy process, AHP. The proposed system could deliver 2.58 kW of the electric power as well as 23.3 m3 of the fresh water per day with a production cost of 0.25 $ kWh−1 and 0.66 $ m−3, respectively.