<p>This study investigates alternative configurations of a dual-pressure heat recovery steam generator (HRSG) in a combined cycle power plant with the objective of enhancing power generation efficiency. Four design arrangements are examined, with the primary novelty lying in the introduction of a new HRSG configuration integrated with multi-objective optimization and an emergy-based assessment framework. To comprehensively evaluate system performance, a five-dimensional (5E) analysis—encompassing energy, exergy, economic, emergoeconomic, and emergoenvironmental perspectives—is employed. The optimization process is conducted using a heuristic algorithm aimed at maximizing exergy efficiency while minimizing the total annual cost (TAC). Comparative results indicate that Configuration 2, comprising a high-pressure superheater, high-pressure evaporator, low-pressure superheater, high-pressure economizer, low-pressure evaporator, and low-pressure economizer arranged in series, delivers the most favorable performance. This configuration achieves the highest net power output of 56,345 kW, accompanied by improved eco-efficiency. Under optimized conditions, the system attains an exergy efficiency of 39.44% with a TAC of 2.1232 <InlineEquation ID="IEq1"> <EquationSource Format="TEX">$\times {10}^{6}$</EquationSource> <EquationSource Format="MATHML"><math> <mrow> <mo>×</mo> <msup> <mrow> <mn>10</mn> </mrow> <mn>6</mn> </msup> </mrow> </math></EquationSource> </InlineEquation> $/year. Further insights from exergy analysis reveal a total exergy destruction rate of 32.094 MW, predominantly occurring in the condenser. From an economic standpoint, the total capital investment is estimated at 1.6135 <InlineEquation ID="IEq2"> <EquationSource Format="TEX">$\times {10}^{7}$</EquationSource> <EquationSource Format="MATHML"><math> <mrow> <mo>×</mo> <msup> <mrow> <mn>10</mn> </mrow> <mn>7</mn> </msup> </mrow> </math></EquationSource> </InlineEquation> $, with the steam turbine constituting the largest cost share (4.7600 <InlineEquation ID="IEq3"> <EquationSource Format="TEX">$\times {10}^{6}$</EquationSource> <EquationSource Format="MATHML"><math> <mrow> <mo>×</mo> <msup> <mrow> <mn>10</mn> </mrow> <mn>6</mn> </msup> </mrow> </math></EquationSource> </InlineEquation> $). The levelized cost of electricity is calculated to be 79.54 $/MWh. Moreover, the emergy-based evaluation indicates a monetary impact rate of 9.6291 <InlineEquation ID="IEq4"> <EquationSource Format="TEX">$\times {10}^{10}$</EquationSource> <EquationSource Format="MATHML"><math> <mrow> <mo>×</mo> <msup> <mrow> <mn>10</mn> </mrow> <mn>10</mn> </msup> </mrow> </math></EquationSource> </InlineEquation> sej/kWh and an ecological impact rate of 1.0942 <InlineEquation ID="IEq5"> <EquationSource Format="TEX">$\times {10}^{14}$</EquationSource> <EquationSource Format="MATHML"><math> <mrow> <mo>×</mo> <msup> <mrow> <mn>10</mn> </mrow> <mn>14</mn> </msup> </mrow> </math></EquationSource> </InlineEquation> sej/kWh for power generation. Overall, the results present an integrated and systematic assessment of the proposed HRSG configuration, demonstrating its technical feasibility, economic competitiveness, and environmental sustainability.</p>

Innovative multi-objective design of dual-pressure HRSG based on emergy and exergy analysis

期刊论文
发表日期：

2026年5月5日

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A. Saleh,
H. Hajabdollahi

摘要

This study investigates alternative configurations of a dual-pressure heat recovery steam generator (HRSG) in a combined cycle power plant with the objective of enhancing power generation efficiency. Four design arrangements are examined, with the primary novelty lying in the introduction of a new HRSG configuration integrated with multi-objective optimization and an emergy-based assessment framework. To comprehensively evaluate system performance, a five-dimensional (5E) analysis—encompassing energy, exergy, economic, emergoeconomic, and emergoenvironmental perspectives—is employed. The optimization process is conducted using a heuristic algorithm aimed at maximizing exergy efficiency while minimizing the total annual cost (TAC). Comparative results indicate that Configuration 2, comprising a high-pressure superheater, high-pressure evaporator, low-pressure superheater, high-pressure economizer, low-pressure evaporator, and low-pressure economizer arranged in series, delivers the most favorable performance. This configuration achieves the highest net power output of 56,345 kW, accompanied by improved eco-efficiency. Under optimized conditions, the system attains an exergy efficiency of 39.44% with a TAC of 2.1232 $\times {10}^{6}$ $\times 10^{6}$ $/year. Further insights from exergy analysis reveal a total exergy destruction rate of 32.094 MW, predominantly occurring in the condenser. From an economic standpoint, the total capital investment is estimated at 1.6135 $\times {10}^{7}$ $\times 10^{7}$ $, with the steam turbine constituting the largest cost share (4.7600 $\times {10}^{6}$ $\times 10^{6}$ $). The levelized cost of electricity is calculated to be 79.54 $/MWh. Moreover, the emergy-based evaluation indicates a monetary impact rate of 9.6291 $\times {10}^{10}$ $\times 10^{10}$ sej/kWh and an ecological impact rate of 1.0942 $\times {10}^{14}$ $\times 10^{14}$ sej/kWh for power generation. Overall, the results present an integrated and systematic assessment of the proposed HRSG configuration, demonstrating its technical feasibility, economic competitiveness, and environmental sustainability.