Question

The figure below shows a condenser/cooling tower pipe system needed to remove heat from a water cooled refrigeration condenser and reject the heat to the atmosphere. The amount of heat to be rejected to the atmosphere is 480,000 Btu/hr. The water enters the condenser at 85"F, and the temperature rise of the water through the condenser is 10°F. The total length of the piping in the system is 60 ft. Fittings are as shown. Assume bends to be as shown to be 90·standard radius. All piping is schedule 40 commercial steel with flanged fittings. The loss coefficient for the strainer is twice that of the globe valve The total head loss through the condenser is 7 ft, and the difference in height between the cooling spray header and the sump where the water is collected is 10 ft. The piping inlet for the sump is square inlet Neglect head loss through the spray nozzlies 2. a. Determine the water flow rate. b. Size the piping according to the Vmax-S ft/s or dh/100 max 4 ft c. List the loss coefficients for each minor loss, and compute the total minor losses d. Compute the actual major losses using the Darcy-Welsbach equation. How do they compare to the chart values? e. Compute the required head of the pump、Choose a pump speed and impeller diameter from Fig 10.11 Assuming 20 ft of suction line and the pump centerline to be 3 ft below the surface of the water in the sump, compute the NPSHa at the Inlet to the pump. f. Cooling tower Strsiner Globe valves Pump Condenser

Answer 1

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