AIR FIN COOLER
“Air fin cooler are heat transfer equipment used for removing heat from process fluid to the atmosphere”.for:
- condensing(By removing latent heat of vaporization)
- Partial condensing
Air fin cooler assembly consists of :
- Tube bundle for process fluid flow and heat transfer.
- Fan assembly for providing air flow to remove heat.
Significance of air fin coolers :
No shell required, header ends similar shell & tube type.
Air velocity is typically 1.5 to 3.4 m/s.
Approach temp achieved practically is 8 to 14 deg c .
External fins provided on the tubes for increasing heat transfer area.
- High level of heat removal is required.
- Where cooling water not available.
- Where ambient temp is low.
- Problem of frequent fouling and corrosion.
- Higher investment.
- 4 to 10 times more ground space in shell & tube type.
- Low heat transfer coefficient of air results in large heat transfer area.
ADVANTAGE OF AIR FAN COOLERS
- Eliminates high cost of cooling water treatment.
- Reduced maintenance as water fouling properties are eliminate.
- Independent of water supply location.
- Temperature of process fluid can be controlled by varying the air flow through variable pitch fans, variable speed motor.
DIS-ADVANTAGE OF AIR FAN COOLERS
- Air has poor heat transfer coefficient hence, Air fan cooler occupy spaces.
- Large moving part like fans, motors generating noise due to high air turbulence.
- Moving parts increase maintenance costs.
TYPES OF AIR COOLED HEAT EXCHANGER
- Humidified forced-draft
Forced draft air fin coolers:
- “Air forced across tube bundle by fan located in air plenum below bundle”
- Low HP
- Possibility of re circulation of hot air.
- Easy accessibility to motors.
- Lesser air distribution compared to induced draft.
- Parts:Fan, Nozzle, Fan ring, Plenum,Header, Tube bundle, Drive assembly,Inlet bell, Column support.
Induced draft air fin coolers:
- Fan located above hood covering tube bundle.
- Air pulled across tube bundle and exhausted through hood.
- Better and hot air is not re circulated.
- Higher hp.
- Fins protected.
Humidified forced-draft coolers:
Air humidified before forced across tubes.
Evaporation draws heat from air and cools air below temperature of process fluid.