3. In a shell-and-tube heat exchanger under design condition, the cooling water gets heated from 30°C to 45°C while the process stream is cooled from 100°C to 60°C. Due to

fouling only in the process side, the mass flowrate of water has to be increased to 160% of the design flow to maintain the process side outlet temperature at its design value with the same design flowrate of the process stream. Express the fouling heat transfer coefficient (ho), which is the inverse of the fouling heat transfer resistance, as a multiple of process side heat transfer coefficient (ho). Assume that under design condition, there is no fouling. Also assume that all the resistance to heat transfer is on the process side.

Fig: 1