Experiments

  • General Operating Procedures of Cooling Tower.
  • General Observation of the Forced Draught Cooling Tower.
  • End State Properties of Air and Steady Flow Equations.
  • Investigation of the Effect of Cooling Load on Wet Bulb Approach.
  • Investigation of the Effect of Air Velocity on Wet Bulb Approach and Pressure Drop through the Packing.
  • Investigation of the Relationship between Cooling Load and Cooling Range.
  • Measurement of water and air flow rates temperature and humidity.
  • Cooling tower performance.

Basic Cooling Tower Unit

The unit comes complete with the following main components:

Load Tank

The load tank is made of stainless steel having a capacity of approximately 9 liters. The tank is fitted with two cartridge heaters, 1kW and 1.0 kW each, to provide a total of 2 kW cooling load.

A make-up tank is fixed on top of the load tank. A float type valve at the bottom of the make-up tank is to control the amount of water flowing into the load tank.

A centrifugal type pump is supplied for circulating the water from the load tank through a flowmeter to the top of the column, into the basin and back to the load tank. A temperature sensor and temperature controller is fitted to load tank to prevent overheating.

A level switch is fitted to the load tank so that when a low level condition occurs, the heater and the pump will be switched off.

Air Distribution Chamber

The stainless steel air distribution chamber comes with a water collecting basin and a one-side inlet centrifugal fan. The fan has a capacity of approximately 235 CFM of air flow. The air flowrate is adjustable by means of an intake damper.

Column and Packing

One packed column is available. The column is a standard column that comes together with this unit.

The column is made of clear acrylic with a square cross-sectional area of 225 cm2 and a height of 60 cm. It comes with eight decks of inclined packing. A top column that fitted on top of the column comes standard with a sharp edged orifice, a droplet arrester and a water distribution system.

Packed column: 100 m2/m3

 Measurements

Temperature sensors are provided to measure the inlet and outlet water temperatures as well as the make-up tank water temperature. In addition, temperature sensors have been installed to measure the dry bulb and wet bulb temperatures of inlet and outlet of the air. The followings show the list of codes assigned to each temperature sensors.

  • T1 Dry Bulb Temperature of the Inlet Air.
  • RH1 Relative Humidity of Inlet Air.
  • T2 Dry Bulb Temperature of the Outlet Air.
  • RH2 Relative Humidity of Outlet Air.
  • T3 Inlet Water Temperature.
  • T4 Outlet Water Temperature.
  • T5 Make up Tank Temperature.
  • T6 Hot Water Tank Temperature.

An inclined manometer is provided for the measurement of pressure drop across the packed column. On the other hand, the inclined manometer and the orifice are also used to determine the air flowrate.

A flowmeter is provided for the measurement of water flowrate. The flowmeter is ranged at 0 to 7 LPM.

Water Circuit

Water temperature in the load tank will be increased before the water is pumped through a control valve and flow meter to the column cap. Before entering the column cap, the inlet temperature of the water is measured and then the water is uniformly distributed over the top packing deck.

This creates a large thin film of water, which is exposed to the air stream. The water gets cooled down, while passing downward through the packing, due to the evaporation process. The cooled water falls into the basin below the lowest deck and return to the load tank where it is re-heated before re-circulation. The outlet temperature is measured at a point just before the water flows back into the load tank. Evaporation causes the water level in the load tank to fall.

The amount of water lost by evaporation will be automatically compensated by equal amount from the make-up tank. At steady state, this compensation rate equals the rate of evaporation plus any small airborne droplets discharged with the air.

Air Circuit

A one-side inlet centrifugal fan draws the air from the atmosphere into the distribution chamber. The air flow rate is varied by means of an intake damper.

The air passes a dry bulb temperature sensor and wet bulb temperature sensors before it enters the bottom of the packed column. While the air stream passes through the packing, its moisture content increases and the water temperature drops.

The air passes another duct detector measuring its exit temperature and relative humidity, then through a droplet arrester and an orifice, and finally leaves the top of the column into the atmosphere.

Software TH-3130SW (optional)
DAQ software specially designed in National Instrument™, LABVIEW™ environment to measure and calculate the results of apparatus. The software is optional and while using software a set of electronic sensors are included. Software can be run with any Windows™ environment.