Recently, producing and using energy in an efficient way is one of the challenges through the world. Additionally, the severe environmental issues regarding global warming and ozone depletion have risen. Having taken into consideration two aspects, waste heat recovery systems can be an effective solution to solve some of these problems. This study presents the waste heat recovery potential applied to stationary internal combustion engines. Through the work, three different diesel engines’ exhaust gases are applied as the heat sources. Three Organic Rankine Cycle (ORC) configurations are designed, a Simple Organic Rankine Cycle and Regenerative Organic Rankine cycle which are thermally powered by exhaust gases and Pre-heating and Regenerative Organic Rankine Cycle with the usage of exhaust gas and the engine cooling water as the heat sources. In order to assess the differences between the chemical classes regarding the ozone depletion and global warming potential, eight candidate working fluids are chosen. A selecting procedure is created to obtain the most appropriate working fluid for the suitable cycle configuration. The first law of thermodynamic analysis is conducted with the variations of the working fluids, heat sources and the cycle designs in order to accomplish the greatest thermal efficiency with the most suitable working fluid and the configuration. It was found that it is possible to achieve a high thermal efficiency outcome using zero ozone depletion and global warming potential fluids under the Regenerative Organic Rankine configuration.