COOLING TOWER MATERIAL BALANCE

Quantitatively, the material balance around a wet, evaporative cooling tower system is governed by the operational variables of make-up flow rate, evaporation and windage losses, draw-off rate, and the concentration cycles.

Air Flow Generation Methods in Cooling Tower:

With respect to drawing air through cooling tower, there are three types of cooling towers:

1)      Natural Draft: Utilizes buoyancy via a tall chimney. Warm, moist air naturally rises due to the density differential compared to the dry, cooler outside air. Warm moist air is less dense than drier air at the same pressure. This moist air buoyancy produces an upwards current of air through the tower.

COOLING TOWER

A cooling tower is a heat rejection device which rejects waste heat of water to atmosphere through cooling of a water stream to a lower temperature. Cooling towers may either use evaporation of water to remove process heat and cool the working fluid to near the wet-bulb air temperature or, in the case of closed circuit dry cooling towers, rely solely on air to cool the working fluid to near the dry-bulb air temperature.

BASICS OF AIR HANDLING UNIT AND ITS DESIGN

In this article we know the followings:

1)     Know the different types of AHUs, and their basic anatomy

2)     Understand the codes and standards that govern AHU specification

3)     Learn about how energy can be saved in HVAC systems that use AHUs.

A basic definition of an air handling unit (AHU) might be “a box with a fan, coils, and filters.” From there it gets considerably more complicated.

Air Handling Unit

Air Handling Unit

There are basically two types of Air Handling Unit that are in used and they are the "Draw-Through" or "Blow-Through". 

In Draw-Through type, the fan pulls the air through the mixing box, filters and cooling coil before discharging it from the fan outlet to the space to be conditioned or to the ducting network. The design can be vertical or horizontal. In this case, the section before the fan has negative pressure.

Fluid Mechanics

Fluid mechanics is categorises into three section

a)     Kinematics - Study of motion without taking help of force.

b)     Dynamics - Study of motion with taking help of force.

c)     Statics – Study of fluid mechanics in which fluid particles are at rest.

Fluid – A fluid is a substance which continuously deforms under the action of tangential / shears forces.