Heat exchangers horsepower

Calculate horsepower per fan from the previous section, Air-cooled Heat Exchangers, Pressure Drop, Air Side. 

Process flow diagrams are more complex and show all main flow streams including valves to enhance the understanding of the process as well as pressures and temperatures on all feed and product lines within all major vessels and in and out of headers and heat exchangers, and points of pressure and temperature control. Also, information on construction materials, pump capacities and pressure heads, compressor horsepower, and vessel design pressures and temperatures are shown when necessary for clarity. In addition, process flow diagrams usually show major components of control loops along with key utilities. 

The theoretical maximum cooling capacity of a heat exchanger for a hydraulic system will never have to be greater than the input horsepower to the system. Usually its capacity can be considerably less, based on the calculated input horsepower. A mle of thumb is to provide a heat exchanger removal capacity of about 25 per cent of the input horsepower. Rarely, even on inefficient systems, would a capacity of more than 50 per cent be required. 

When ordering a heat exchanger the information furnished to your supplier must include the maximum rate of oil flow, in GPM, through the heat exchanger, and the horsepower or BTU per hour of heat to be removed. On water-cooled models, state the maximum rate of water flow that will be available. For best water usage, the water flow should be approximately one-half of the oil flow. Specify the temperature of the cooling water. 

The computer program PROG84 calculates the air cooled heat exchanger area, the face area and the fan horsepower. Table 8-24 shows both the input data and computer output of the design calculations. The exchanger area is 1602 ft and the LMTD is 52°F. Face area of the bundle... 

---