Problem
A plant returns 15,000 kg/h condensate at 90°C instead of using make-up water at 30°C. Calculate sensible heat saving using cp=4.187 kJ/kg·K.
Given Data
Write all quantities in consistent SI units before substitution.
Formula and Solution
Saving = 15,000×4.187×(90−30)=3,768,300 kJ/h = 1,046.75 kW, before accounting for other system effects.
Engineering Check
Check units, magnitude and physical meaning. State any simplifying assumptions and avoid mixing mass flow per hour with energy per second.
Practice Variation
Repeat the problem after changing one input by 10% and explain how the answer responds.