Steam in a condenser in a power plant must be condensed at a temperature of 30 ° C using cooling water from a nearby lake. In other words, water vapor at 30 ° C must be condensed to liquid at 30 ° C. The water from the lake goes into pipes with a temperature of 14 ° C and out of the pipes with a temperature of 22 ° C. The area of the pipes is 45 m2. The heat transfer coefficient is 2100 W m-2 K -1.
Determine the mass flow of the cold water [kg / s] and how fast the steam condenses [kg / s].
The heat of vaporization to water at 30 ° C is 2431 kJ / kg. The heat capacity of the cold water is 4184 J kg-1 K-1.