GATE 2018 ME (ME2) – Question 64
Steam in a thermal power plant condenser condenses at 30°C. Cooling water enters tubes at 14°C and exits at 22°C. Total tube surface area is 50 m² and overall heat-transfer coefficient 2000 W/(m²·K). Find heat-transfer rate to the condenser (MW), to two decimal places.
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Correct answer: 1.14 to 1.16
Explanation
Condensing steam remains at 30°C. Terminal differences are 16 K and 8 K. Thus $\Delta T_{\rm lm}=(16-8)/\ln(16/8)=11.54156$ K. Heat rate is $UA\Delta T_{\rm lm}=2000(50)(11.54156)=$ **1.15 MW**.