Heat exchangers fin-fan

SPECIFICATIONS FOR FIN FAN HEAT EXCHANGERS FLUOR GRISCOM RUSSELL... 

When cooling water is scarce, air is used for cooling and condensing liquid streams in fin-fan heat exchangers. A common configuration is shown in Figure 13.11. See, also, a video of an industrial fin-fan cooler on the CD-ROM that accompanies this text. The liquid to be cooled... 

Fan, Y. N., How to Design Plate-Fin Exchnagers, Heat Exchanger Design Handbook, Gulf Publishing Company (1968) p. 59. 

Finned-tube, air-cooled heat exchangers are usually placed in elevated locations, often above pipe racks. Finned-tube heat exchangers that are fan-... 

In petrochemical plants, fans are most commonly used ia air-cooled heat exchangers that can be described as overgrown automobile radiators (see HeaT-EXCHANGEtechnology). Process fluid ia the finned tubes is cooled usually by two fans, either forced draft (fans below the bundle) or iaduced draft (fans above the bundles). Normally, one fan is a fixed pitch and one is variable pitch to control the process outlet temperature within a closely controlled set poiat. A temperature iadicating controller (TIC) measures the outlet fluid temperature and controls the variable pitch fan to maintain the set poiat temperature to within a few degrees. 

Air-cooled heat exchangers include a tube bundle, which generally has spiral-wound fins upon the tubes, and a fan, which moves air across the tubes and is provided with a driver. Electric motors are the most commonly usea drivers typical drive arrangements require a V belt or a direc t right-angle gear. A plenum and structural supports are basic components. Louvers are often used ... 

Above this size, the flow of air over the condenser surface will be by forced convection, i.e. fans. The high thermal resistance of the boundary layer on the air side of the heat exchanger leads to the use, in all but the very smallest condensers, of an extended surface. This takes the form of plate fins mechanically bonded onto the refrigerant tubes in most commercial patterns. The ratio of outside to inside surface will be between 5 1 and 10 1. 

Pumps handling flammable materials should not be located under pipe racks as an ignited spill could rapidly allow fire to rise and envelop the overhead pipework. Finned-tube, air-cooled heat exchangers, often fan-forced, are frequently mounted above pipe rack structures. 

S H E = Solution heat exchanger F = Fan fins P = Main duty pump... 

Table 2.9 Revamp options for heat exchangers and fin fan (or air) coolers. Equipment - Objective Options...

Heuristic 56 For an air-cooled exchanger, the tubes are typically 0.75-1.00 in. in outside diameter. The ratio of fin surface area to tube outside bare am is large at 15-20. Fan power requirement is in the range of 2-5 Upper million Btu/hr transferred, or about 20 Hp per 1,000f of tube outside bare surface (fin-free) area. Minimum approach temperature is about 50°F, which is much higher than with water-cooled exchangers. Without the fins, overall heat transfer coefficients would be about 10 Btu/hr ft °F. With the fins, U = 80-100 Btu/hr fF °F, based on the tube outside, bare surface area. 

Currently the most popular cooling method is the externally controlled passive cooling technique using traditional convection heat transfer and heat exchanging techniques such as fins [1], a fan [3], and compressed air for microfluidic device cooling. Integrated cooling techniques for microfluidic devices are very limited such as the Peltier thermoelectric cooler [2] and endothermic cooler [7] mentioned above. 

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