Cooling Tower, CT is an equipment which is used to lower the temperature of water by extracting heat from the water and then emitting heat into the atmosphere. Cooling towers utilize the contact of water and air in the heat transfer process which the heat is then discharged into the atmosphere. Looking to the inside cooling tower system, there are fan, distribution system, spray nozzle, packing, basin and pump.
Hot water from the process or cooling system of engine goes to cooling tower in order to lower the water temperature so the water can be used again as cooling media.
Performance of Cooling Tower
In general, process diagram can be seen in picture below;
Some parameters used in evaluating the performance of cooling tower are:
(1) Range is difference between water temperature in and out of cooling tower. The high range value shows that cooling tower can lower water temperature effectively and its performance is quite good.
(2) Approach is difference between temperature water out and ambient wet bulb temperature. Lower the approach value better the performance of cooling tower.
(3) Efficiency of cooling tower is comparison of range to ideal range or difference between water temperature in and ambient wet bulb temperature. Efficiency of Cooling Tower can be represented as:
Higher this comparison value, higher the efficiency of cooling tower.
Heat releasing or cooling process in cooling tower happens because there is heat exchanging between hot water from production unit and atmosphere. The equipment used to accelerate the heat releasing is fan. The amount of heat releasing is influenced by the width of contact surface between hot fluid and cold fluid, contact time, fluid speed and fluid temperature.
In optimizing the performance of cooling tower, there are things need to be concerned. Some of the are maintenance and tower clean by controlling algae growth. Algae can cause deposits forming, fouling, corrosion and scale. Uncontrolled algae growth will cause local corrosion, blockage and heat transfer efficiency decreasing. The impact of it, fan has to work harder to keep the heat releasing in optimum condition. Finally the energy which is consumed increase.
If maintenance and cleaning are executed periodically, so the efficiency can be kept as good as possible, then the fan is working relative lightly. If fan power after treatment is assumed same or close to design, the example of saving calculation which the writer has audited can be shown in table below:
If working hour a month is 206 hours, then the energy and cost saving amount are 8,956 kWh/year and Rp 11,642,962/year.