In a palm oil processing plant, the crude oil is heated using hot water from a furnace. The furnace burns oil palm biomass to heat water (initial water temperature of 18 C). After the hot water was used to heat the crude palm oil, the hot water (p = 4180 J/kg. C) was then discharged to the drain at a rate of 7 kg/min at a temperature of 70C. The furnace has an efficiency of 82% and operates for 9 hours a day, 6 days a week, and 48 weeks in a year. The cost for 1 tonne of oil palm biomass is RM 18 (1 tonne = 105,500 kJ). Hence, the mill engineer intends to install heat exchangers to save on operating costs. This heat exchanger will use the hot water discharged into the drain earlier to pre-heat the new water before entering the furnace as shown in Figure 4. However, only 75% of the heat from the previously discharged water can be used. Determine: a) Heat transfer rate for heat exchangers Hot water 70C Cold water 18C Figure 4