The plant manager of a large industrial manufacturing facility plans to install a heat exchanger to use condenser-cooling water from its onsite steam power plant to pre-heat process cleaning water entering the manufacturing plant.
The process cleaning water, with a flow rate of 1800kg/hour is required to leave the counterflow simple single pass tube heat exchange at a temperature of 60°C having entered the exchanger at 20°C.
The condenser cooling water is available at an inlet temperature of 70°C and must be returned to the cooling system at a temperature no greater than 20°C.
I. Sketch the temperature distribution along the exchanger length for both counter flow and parallel flow heat exchanger configurations. Briefly explain why the counter flow arrangement is more effective per unit area.
II. Using the Log mean temperature Difference Method (LMTD) for an overall heat transfer coefficient of 0.5kW/m^2K and assuming a specific heat capacity of both fluids to be 4.181kJ/kg*K, complete the following for the counter flow heat exchanger:
i) State the assumption to be made when completing a LMTD analysis.
ii) Calculate the require flow rate of the condenser cooling water.
iii) Calculate the required heat dissipation rate achieved.
iv) Calculate the required heat transfer surface area for this installation.