COMPARATIVE MAXIMUM POWER DENSITY ANALYSIS OF A SUPERCRITICAL CO2 BRAYTON POWER CYCLE

Asım Sinan Karakurt

doi:10.18186/thermal.671148

Abstract

The supercritical CO2 (s-CO2) power cycle has been taking into account as one of the most effective alternatives for energy conversion because of its higher efficiency and smaller compressor and turbine sizes for many years. A plenty number of parametric and experimental studies for the different type of s-CO2 cycles have been accomplished in the literature. In this paper, a performance analysis based on a power density criterion has been carried out for a simple s-CO2 Brayton power cycle. The parameters which are obtained from analyzes were compared with those of a power performance criterion that is shown that design parameters at maximum power density give a chance to smaller cycle components and more efficient s-CO2 Brayton power cycle. Due to loses in the cycle, the power and thermal efficiency will reduce by a certain amount, however, the maximum power density conditions will still give a better performance than at the maximum power output conditions. The analysis exemplified in this paper may provide a reference for the finding of optimal operating conditions and the design parameters for real s-CO2 Brayton power cycles.

Highlights

The Brayton cycle based on supercritical carbon dioxide (s-CO2) as the working fluid is an innovative concept for converting thermal energy to electrical energy
It is shown that design parameters at maximum power density give a chance to smaller cycle components and more efficient supercritical CO2 (s-CO2) Brayton power cycle
Ηth and rbw of the s-CO2 cycle is seen to increase with increasing rp When considering α is 2.5 and constant as figure 2, the cycle thermal efficiency is 24.83%, 25.28% and 25.47%, respectively, by increasing rp from 8.673 to 9.898 and 11

Summary

Introduction

The Brayton cycle based on supercritical carbon dioxide (s-CO2) as the working fluid is an innovative concept for converting thermal energy to electrical energy. Studies on the real-time response of s-CO2 power cycles and the development of cycle control strategies [17,18,19], research on turbo machines specially designed for s-CO2 flow and on air bearings and seals with turbo machine subcomponents [20,21,22,23], the work consists of studies on high speed electric motor technologies which is essential component for the s-CO2 cycles to be compact [24,25,26,27,28] and material investigations on the interaction of different materials with s-CO2 fluid under high temperature and pressure [29,30,31,32]. Gonca et al [38] studied comprehensive analyses and comparisons for irreversible cycle engines and they examined effects of design parameters on MPD.

Results

Conclusion