Adiabatic gas-liquid contact system for problem

Cooling towers are classified according to the method by which air is introduced to the tower. The principal types are atmospheric spray, natural-draft, mechanical-draft, deck-filled, spray-filled, coil shed and hyperbolic towers. Most industrial cooling tower installations are field-erected units designed for specific thermal characteristics. 

In an atmospheric spray tower the air movement - is dependent on atmospheric conditions and the aspirating effect of the spray nozzles. Natural-draft cooling tower operation depends on a chimney or stack to induce air movement. Mechanical-draft cboling towers utilize fans to move ambient air through the tower. Deck-filled towers contain tiers of splash bars or decks to assist in the breakup of water drops to increase the total water surface and subsequently the evaporation rate. Spray-filled towers depend only on spray nozzles for water breakup. Coil shed towers are comprised of a combination structure of a cooling tower installed on top of a substructure that contains atmospheric section coils. Hyperbolic natural-draft cooling towers are typically large-capacity systems. 

There is also a separate class of towers based on a dry cooling principle. Each of these major designs is described below. 

Cooling towers are broadly classified on the basis of the type of draft natural draft (natural convection), mechanical draft (forced convection) and mechanical and natural. Further distinction is made based on (1) the type of flow—crossflow, counterflow, cocurrent flow (2) the type of heat dissipation—wet (evaporative cooling), dry, wet-dry and (3) the type 

WET-DRY PARALLEL FLOW A LEGEND X FANS WATER MANIFOLD C=i DRY FILL RACK  

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Figure 3.8 Adiabatic gas-liquid contact system for problem 3.9.

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