A) An insulated stream of warm water is produced in a steady flow mixing process by combining 1 kg/s of cold water at 25 °C with 0.8 kg/s of hot water at 75 °C. What is the temperature of warm-water stream? what is the work of the mixing process, Q, and AU ? assume the specific heat of water is constant at 4.18 kJ/kg.K.

Define C.O.P. of the simple vapor compression refrigeration cycle R-717. The evaporation temperature is -15 ° C and the condenser temperature is 30 ° C. COP =

Question 1.2 A helical coil cooler is used to cool 0.5 kg.s¹ of hot oil from 100°C down to 40°C. Cooling water with an inlet temperature of 10°C flows inside the coiled tube. The specific heat of the oil is 2 kJ.kg¹.K¹, the specific heat of the water is 4.2 kJ.kg¹.K¹, and the density of water is 1000 kg.m. a) Determine the lowest possible cooling water flow rate. (0.48 kg.s¹) b) Determine the inside diameter of the tube if a cooling water flow of 1.5 times the minimum is used, and the recommended flow velocity is 1 m.s. Select an appropriate tube from the following standard sizes: Outside diameter (mm) Wall thickness (mm) 30 1.5 35 2.0 40 2.0 45 2.5 50 3.0 c) For a heat transfer coefficient of U = 800 W.m2.K, determine the heat transfer surface area and the tube length of the heat exchanger. The oil inside the tank is mixed by a stirrer and the oil temperature at any location in the tank can be assumed to be equal to the oil outlet temperature. (Area = 4.12 m², length = 39.7 m)