A condenser is used as a heat exchanger in a large steam power plant in which steam is condensed to liquid water. The condenser is a shell and tube heat exchanger which consists of 1 shell and 20,000 tubes. Water flows through each of the tubes at a rate of 1 kg/s with an inlet temperature of 30 °C. The steam in the condenser shell condenses at the rate of 430 kg/s at a temperature of 50 °C. If the heat of vaporization is 2.326 MJ/kg and specific heat of water is 4 kJ/(kg.K), the effectiveness of the heat exchanger is _______ (rounded off to 3 decimal places).
During open-heart surgery, a patient’s blood is cooled down to 25 °C from 37 °C using a concentric tube counter-flow heat exchanger. Water enters the heat exchanger at 4 °C and leaves at 18 °C. Blood flow rate during the surgery is 5 L/minute.
Use the following fluid properties :
$$ \begin{array}{|c|c|c|} \hline \text { Fluid } & \text { Density }\left(\mathrm{kg} / \mathrm{m}^3\right) & \text { Specific heat }(\mathrm{J} / \mathrm{kg}-\mathrm{K}) \\ \hline \text { Blood } & 1050 & 3740 \\ \hline \text { Water } & 1000 & 4200 \\ \hline \end{array} $$Effectiveness of the heat exchanger is _________ (round off to 2 decimal places).