Combined-Cycle System With Novel Bottoming Cycle

TLDR

The project aims to replace the Rankine bottoming cycle in combined‑cycle power plants with a new multicomponent working‑agent cycle that can also generate electricity from low‑temperature heat sources, and an experimental installation is underway. The new cycle uses exhaust heat from a gas turbine as a bottoming cycle, boosting overall plant efficiency by up to 20 % and is slated to become operational by the end of 1984. Design and cost studies show the cycle delivers 1.6–1.9× higher efficiency than Rankine, achieves 50–52 % thermal efficiency with conventional gas turbines, and offers lower investment cost per unit power in direct proportion to its energy advantage.

Abstract

A new thermodynamic energy cycle has been developed using a multicomponent working agent. This cycle is designed to replace the currently used Rankine Cycle as a bottoming cycle for a combined-cycle energy system as well as for generating electricity using low-temperature heat sources. Several combined power systems based on this cycle have been designed and cost-estimated. The efficiency of this cycle is from 1.6 to 1.9 times higher than that of the Rankine Cycle system, at the same border conditions. The investment cost per unit of power output for this cycle is lower than that for the Rankine Cycle system in approximately direct proportion to the energy advantage. The application of this cycle as a bottoming cycle in combined-cycle systems involves the use of an energy system which utilizes heat from the exhaust of a gas turbine, resulting in an increase in overall efficiency of up to 20 percent above the efficiency of the combined systems using the Rankine bottoming cycle. As a result, a thermal efficiency in the range of 50–52 percent can be achieved using a conventional gas turbine. The project to build the first experimental installation is now in progress. This installation is to become operational at the end of 1984.