Investigation of intercooler-effectiveness on exergo-economic and exergo-sustainability parameters of modified Brayton cycles

Abstract

The paper investigates the variants of intercooler effectiveness on exergo-economic and exergo-sustainability indicators of modified Brayton cycles. The objective is to ascertain how the variant in the intercooler effectiveness affects the exergy-based parameters. However, to achieve this, a component by component exergy-cost balances was established. The considered cycles include: the non-specific cycle (Case 1) comprising a gas turbine (GT), intercooler (IC), heat exchanger (HE) and reheat system (REH), others include (GT+H+REH +ST, Case 2), (GT+HE +IC +REH +ST+FWH, Case 3) and (GT+HE+IC+REH +ST+2 FWH, Case 4). The calculated cycle efficiencies (Cases 1–4) varies from 17.59% to 28.84% for intercooler effectiveness of 0.75 and 0.95. The exergy destruction within this range was 0.97%, 1.26%, 0.89% and 1.23% (Cases 1, 2 3 and 4) respectively. The component exergy destruction cost (CEDC) fluctuated between 3.85≤CEDC≤229.1$/hr,5.61E−06≤CEDC≤229.1$/h,1.46E−06≤CEDC≤229.1$/hr and 5.61E−06≤CEDC≤229.1$/hr for same order. Additionally, the exergo-sustainability indicators: exergy waste ratio (EWR), environmental effect factor (EFF) and exergetic sustainability index (ESI) were estimated between 17.59≤EEF≤28.84%,0.433≤EWR≤0.6359, 1.55≤ EFF ≤3.60 and 0.277≤ ESI ≤0.644. Conclusively, the intercooler and other modifications have a marginal effect but Cases 4 and 3 was most sustainable with considerable ESI.

Keywords

• Exergo-economics
• Exergo-sustainability
• Intercooler-effectiveness
• Gas-turbine
• Energy