Proposal and analysis of a new combined cogeneration system based on the GT-MHR cycle

In this paper, the waste heat from a gas turbine-modular helium reactor (GT-MHR) is utilized to produce power through two Organic Rankine Cycles (ORCs) and pure water by means of distillation processes. An Absorption heat transformer (AHT) is employed to upgrade the lower temperature waste heat in order to run the desalination system. Detailed thermodynamic analyses for the proposed combined cogeneration cycle (CC cycle) are presented and the effects of important parameters on the cycle performance were studied. The proposed cycle performance is then optimized based on the first law of thermodynamics. The results show that the first law efficiency of the CC cycle, at the optimum conditions, is around 7% higher than that of the GT-MHR cycle. It was also concluded that for each 50 °C increase in the gas turbine inlet temperature, the thermal efficiency is increased by around 2.5–4% and the pure water production rate is decreased by around 6.5%. The results also showed that employing R1234yf as working fluid in the ORCs instead of R123 gives almost the same results in the cycle performance.

► A new GT-MHR based combined cogeneration cycle producing power and pure water is proposed.
► An enhancement of 7% in the first law efficiency with respect to the GT-MHR is obtained.
► The new cycle could produce 12 MW power and 5.3–7.0 kg/s pure water from the GT-MHR waste heat.