Volume 23, Issue 60, July - December, 2026

In-situ effectiveness of cooling water flow at different operating loads: A case study of a 1070MW ultra-supercritical steam power plant

Didi Supandi^♦, Eflita Yohana, Tony Suryo Utomo, Syarif Dwi Priyanto, Muhammad Bagir

Department of Mechanical Engineering, Diponegoro University, Jl. Profesor Sudharto, SH., Semarang 50275, Indonesia

^♦Corresponding Author
Didi Supandi, Department of Mechanical Engineering, Diponegoro University, Jl. Profesor Sudharto, SH., Semarang 50275, Indonesia

ABSTRACT

The cooling water systems play a vital role in large steam power plants as they directly affect the condenser back pressure, turbine efficiency, and overall plant heat rate. This paper presents an in-situ detailed case study of the performance of the cooling water (CW) system in a 1070 MW ultra-supercritical coal-fired steam power plant at three steady-state load levels, i.e., 100% (1070 MW), 75% (803 MW), and 50% (535 MW). Actual operating data obtained from the Distributed Control System (DCS), such as condenser pressure, CW inlet/outlet temperatures, temperature rise (ΔT), CW mass flow rate, exhaust steam flow, heat duty, logarithmic mean temperature difference (LMTD), and total heat transfer coefficient (U), are reviewed and compared to results from a verified steady-state simulation model. The research results show a deviation between the measured and simulated condenser pressure values, with a validation margin of less than 5% for the main parameters. This indicates that cooling water (CW) flow varies under partial load conditions to avoid excessive auxiliary power consumption, and provides quantitative insights for load-dependent optimization of cooling water (CW) flow. The condenser pressure at 50% load is 60.6 mbar, considerably less than the projected 73 mbar, thus affirming the existence of surplus cooling capacity and the opportunity to decrease pump flow. These results are useful in developing better operational strategies for increasing thermal efficiency and decreasing specific auxiliary consumption of large-scale fossil-fuel power plants.

Keywords: Part-load performance, Cooling water flow, Steam power plant, Surface condenser, Condenser backpressure, Thermal optimization, Simulation validation, DCS data.

Indian Journal of Engineering, 2026, 23(60), e14ije1730

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DOI: https://doi.org/10.54905/disssi.v23i60.e14ije1730

Published: 30 September 2026