The Wet Bulb Temperature

Wet bulb temperature is an important factor in performance of evaporative water cooling equipment.  It  is  a  controlling  factor  from  the  aspect  of  minimum  cold  water  temperature  to  which water can be cooled by the evaporative method. Thus, the wet bulb temperature of the air enter-
ing the cooling tower determines operating temperature levels throughout the plant, process, or system.  Theoretically,  a  cooling  tower  will  cool  water  to  the  entering  wet  bulb  temperature, when operating without a heat load. However, a thermal potential is required to reject heat, so
it  is  not  possible  to  cool  water  to  the  entering  air  wet  bulb  temperature,  when  a  heat  load  is applied. The approach obtained is a function of thermal conditions and tower capability.

Wetpoint recommends the initial selection of towers with respect to design wet bulb temperature must be made on the basis of conditions existing at the tower site. The temperature selected is generally close to the average maximum wet bulb for the summer months. An important aspect of wet bulb selection is, whether it is specified as ambient or inlet. The ambient wet bulb is the temperature, which exists generally in the cooling tower area, whereas inlet wet bulb is the wet bulb temperature of the air entering the tower.  The later can be, and often is, affected by discharge vapours being recirculated  into  the  tower.  Recirculation  raises  the  effective  wet  bulb  temperature  of  the  air entering the tower with corresponding increase in the cold water temperature.  Since there is no initial knowledge or control over the recirculation factor, the ambient wet bulb should be specified. The cooling tower supplier is required to furnish a tower of sufficient capability to absorb the effects of the increased wet bulb temperature peculiar to his own equipment.

It is very important to have the cold water temperature low enough to exchange heat or to condense  vapours  at  the  optimum  temperature  level.    By  evaluating  the  cost  and  size  of  heat exchangers versus the cost and size of the cooling tower, the quantity and temperature of the cooling tower water can be selected to get the maximum economy for the particular process.

The below table illustrates the effect of approach on the size and cost of a cooling tower. The towers included were sized to cool 4540m3/hr through a 16.67°C range at a 26.7°C design wet bulb. The overall width of all towers is 21.65 meters; the overall height, 15.25 meters, and the
pump head, 10.6 m approximately.

If you have any query or need your cooling tower cleaning services please contact us for more help and support.

L K Chatuvedi
CEO - Wetpoint Aqua Equipments (P) Ltd
Manufacturer of all kind of Industrial Cooling Towers and Spares
Phone: +91-9302.214.784
Email: ceo@wetpointcoolingtowers.com

How to clean FRP Cooling Towers

Wetpoint follows 2 ways of cleaning a cooling tower. The first type of cleaning is mechanical cleaning and the second type of cleaning is chemical cleaning. Some times, you may follow both methods to accomplish the cleaning task. You can also consult your in house water treatment specialist so that he can assist you to find out the best procedure to follow.

The following steps ensures safety and must be followed before cleaning a cooling tower, no matter if you doing mechanical or chemical cleaning:

1. First and foremost is isolation of cooling tower from the system. Turn off and be sure the tower fan is off, the circulating pumps are off, and the temperature sensors are off.
2. Close all the water valves.
3. Open the drain of the tower from bottom and remove overflow pipe.
4. Once the tower has been drained out get ready and charged with a separate hose.
5. Put-on water proof suit, boots, coveralls, gloves, hat, and face protection.
6. Now you can begin your cleaning.
7. Once cleaned, reverse these steps.

MECHANICAL CLEANING:

To perform mechanical cleaning you may require a power washer, a garden hose with power spray nozzle, shovel, broom, and squeegee. In this cleaning we remove all algae, slight scale, dirt, mud, and collected debris. You can schedule this cleanings to remove dirt to regain cooling performance.

Use pressure wash at the hot deck, cooling tower blades, screen and inside of exhaust collar. While washing remove all the covers of the hot deck and ensure all drain holes are free of scale and debris. We have to wash whole area where water flows in to the fills. While washing please also note if any spray nozzles are missing or broken.

To clean the fills Wetpoint suggest move from top to bottom, outside and inside. While cleaning fills with pressure washer, you have to be more careful as pressure and stream can damage of fills easily. You can use spray stream instead of straight stream.


CHEMICAL CLEANING:

To perform chemical cleaning Wetpoint suggest to decide the purpose of the chemical cleaning as it is very important. Another important thing is you have to consult with your water treatment specialist as there are many tests that need to be performed right before the actual cleaning.

There are 3 separate procedures of chemical cleanings as per following:

A) To loose bio-masses and get into the difficult areas, use of a dispersant.
B) To severe scaling, use of of acid.
C) Disinfection procedure to eliminate and prevent bacteria and Legionella.

Based on recommendations of your water treatment specialist, you have to pick one of the method or combination of the 3 in some cases.

If you have any query or need your cooling tower cleaning services please contact us for more help and support.

L K Chatuvedi
CEO - Wetpoint Aqua Equipments (P) Ltd
Manufacturer of all kind of Industrial Cooling Towers and Spares
Phone: +91-9302.214.784
Email: ceo@wetpointcoolingtowers.com

Cooling tower maintenance cost

A Cooling Tower maintenance doesn’t cost. It pays. Cooling tower is an essential equipment for industry like boilers, central ACs, furnaces etc which are partially depends on Cooling Towers, should not neglect the maintenance of cooling tower. A couple of critical reasons are as follows:

Safety
A cooling tower is used to reduce the heat from the water. By the time water stuck in cooling towers and remain stored in it. The industries have to deal with the threat of Legionella and the other disease caused by the growth of bacteria in the cooling tower. One can remain safe by implementing/schedule the water treatment with biocides. By implementing this we can eliminate that concern and keep your building campus safe.

Reliable, efficient and cost-effective operation of your heating, ventilation and air conditioning system
When any industry skips the cooling tower maintenance schedule, the following effects can be arised in any cooling tower:
1) Accumulated mineral scale, mud, dirt and debris can get into the air conditioning condensers.
2) Scale buildup also causes blockages and uneven water over the fills.
The operation of the system may interrupt, as organizations forcing it to work harder to cool the water. Not only experiencing the cooling issues, but organizations let it be for so long before the system break down. At that point, organizations faced with additional repairing bills of cooling tower maintenance.

Energy savings
Let the example of chiller and cooling tower. This must be noted that when the temperature of system water raised by as little as 2°F, the energy consumption cost raised as much as 6% more. That is because chiller and cooling tower fan needs to work harder and run longer to get the required temperature. And it consumes more energy.

If you are not sure your current heating, ventilation and air conditioning maintenance service provider is doing your cooling tower maintenance according to regulations, it may be time to look into a maintenance contract that is as per your requirements and from a company that can be trusted for quality work.

We at Wetpoint are committed to provide the cost effective cooling tower maintenance services with quality work.

Reach us for more information.

L K Chatuvedi
CEO - Wetpoint Aqua Equipments (P) Ltd
Manufacturer of all kind of Industrial Cooling Towers and Spares
Phone: +91-9302.214.784
Email: ceo@wetpointcoolingtowers.com

Airflow in a Cooling Tower

In any cooling tower the flow of large volume of air can increase rate of evaporation. Reciprocally it will also increase the cooling capacity of the  tower. The cooling tower must have fan of even capacity that can help to maintain and generate that air flow. The selection of fan size depends on the condition of condenser-water temperature, water flow rate and wet-bulb temperature.

One cooling tower may designed with propeller fans or squirrel blowers. In a tower small fans connected to driving motor directly but most of the designs needs intermediate speed control mechanism or speed reduction via power belt or gears. In which the fan and drive system operate in conjunction with the control system to control start/stop and speed. Variable-speed drives, when added to the fan motors, control fan speed and more precisely regulate the temperature of the water as it leaves the tower.

Low airflow in a cooling tower may reduce the transfer of heat from water to the air. Poor airflow can be caused by the following :

• Debris at the inlets or outlets of the tower or in the fill
• Loose fan and motor mountings
• Poor motor and fan alignment
• Poor gearbox maintenance
• Improper fan pitch
• Damage to fan blades or excessive vibration
• Corrosion on fan blades

Reduced airflow due to poor fan performance can ultimately lead to motor or fan failure and can result to cooling tower shut down.

Hence to ensure adequate Airflow in your cooling tower please lineup with above points or contact us for more help and support.

L K Chatuvedi
CEO - Wetpoint Aqua Equipments (P) Ltd
Manufacturer of all kind of Industrial Cooling Towers and Spares
Phone: +91-9302.214.784
Email: ceo@wetpointcoolingtowers.com

water loss in cooling tower

A plant may have chillers, air conditioners or other process equipments. To cool these equipments we utilize Cooling towers so that the heat from circulating water can be dissipate to the ambient air. Cooling towers rejects heat from water to the environment through evaporation. Therefore, by design & architecture, cooling towers use significant amounts of water.

Thermal efficiency and longevity of any cooling tower and their equipments depend on the management of re-circulated water.

Water leaves from cooling tower system from one of following 4 ways:-

1. Evaporation : Evaporation is the primary and for most mechanism and functionality of the tower that transfers heat from the cooling tower system to the environment. 
2.  Drift: Drift is a small quantity of water may be carried from the tower as mist or small droplets. Drift loss is small compared to evaporation and is controlled through drift eliminators.
3. Blowdown: When water evaporates from the tower, dissolved solids such as calcium, magnesium, chloride, and silica remain in the re-circulating water. As more water evaporates, the concentration of dissolved solids increases. If the concentration gets too high, the solids can cause scale to form within the system. The dissolved solids can also lead to corrosion problems. The concentration of dissolved solids is controlled by removing a portion of the highly concentrated water and replacing it with fresh make-up water. Carefully monitoring and controlling the quantity of blow down provides the most significant opportunity to conserve water in cooling tower operations.
4. Basin leaks or overflows: Properly operated towers should not have leaks or overflows. Check float control equipment to ensure the basin level is being maintained properly, and check system valves to make sure there are no unaccounted for losses.

The sum of water that is lost from the tower must be replaced by make-up water:

Make-Up = Evaporation + Blowdown + Drift

A key parameter used to evaluate cooling tower operation is "cycle of concentration" sometimes referred to as cycle or concentration ratio. This is determined by calculating the ratio of the concentration of dissolved solids in the blow down water compared to the make-up water. Because dissolved solids enter the system in the make-up water and exit the system in the blow down water, the cycles of concentration are also approximately equal to the ratio of volume of make-up to blow down water.

Other loses are:

• Water drops carried off by airflow in the form of moist or drift.
• Drift release is not controlled
• Valve leak
• Drawndown/Draw-off

Get expert advice to help determine if a cooling tower required maintenance. Call us or mail us to have a discussion.

L K Chatuvedi
CEO - Wetpoint Aqua Equipments (P) Ltd
Manufacturer of all kind of Industrial Cooling Towers and Spares
Phone: +91-9302.214.784
Email: ceo@wetpointcoolingtowers.com

Cooling Tower Water Distribution

Cooling towers are mechanical devices that are used to reduce the temperature of hot water. We can also interpret cooling tower as heat exchangers that use air and water to transfer heat from systems to outdoor environment.

Hot water from the system is delivered to the top of the cooling tower by the condenser pump via distribution pipes. In an open cooling tower, the hot water is sprayed through nozzles/flower nozzles onto the heat transfer medium i.e. fills/splash bars, in cooling towers we use fills/splashbars inside the cooling tower. Some towers feed the nozzles/flower nozzles through pressurized pipes; while other use gravity to ensure the feed of nozzles/flower nozzles. In this mechanism cooling tower design with water-distribution basin and feed the nozzles/flower nozzles by gravity.

In a closed-loop cooling tower, the water from the condenser loop runs through tubes in the tower and is not exposed to the outside air. Water for cooling the tubes circulates only in the tower.

In the open tower, the cold-water collection basin provided at the base of the tower to gathers cool water after it has passed through the heat transfer medium. The cool water is pumped back to the condenser to complete the cooling-water loop.
While in the closed tower, the condenser water cools as it moves through the piping in the tower and returns to the chiller plant.

If you have any problem or query related to water distribution system please reach us at +91-9302.214.784. We assure you our best of services to correct the cooling tower distribution system.

L K Chatuvedi
CEO - Wetpoint Aqua Equipments (P) Ltd
Manufacturer of all kind of Industrial Cooling Towers
Phone: +91-9302.214.784
Email: ceo@wetpointcoolingtowers.com

Cooling Tower Rebuild Requirements

A decrease of 1.1°C in water temperature results in extra production per hour. The cost of rebuilding cooling tower can be more than paid because increased production creates extra product sale.

It’s a myth that every cooling tower can be rebuilt. Rebuilding a cooling tower does not ensure the return more cooler water or save power or money. Each cooling tower installation must be treated on individual basis i.e. thermal, hydraulic and aerodynamic calculations of existing conditions should be studied by a cooling tower service provider or engineer to see where improvement can be anticipated. Customers can also include their cooling tower testing requirement in the contract.

A cooling tower service provider or engineer can perform a thermal test before and after rebuilding cooling tower. The cooling tower service provider or engineer should provide a report mentioning reasons of the cooling tower's deficiency along with their solutions. In addition to capability percentage the report must include cooling tower specifications along with the estimated budget required to correct the deficiency.

Organizations can be conducted in-house thermal testing for a close estimate. However, a competent cooling tower operator can tell by production results if cooling tower cold water is adequate or not.  Allow a competent cooling tower engineer with approved instrumentation to handle it. Only a certified test will provide the capability percent at which the tower is operating, compared to the 100% for which it was purchased. 

Due to the added cost of new ba-sin, piping and wiring, rebuilding and retrofit should be considered. The expense of retrofitting and rebuilding a cooling tower to upgrade its capacity or capability has a rapid payback if the proper investigative engineering is performed. The points mentioned above are few and far between, but good care and attention can help to identify them. 

Wetpoint is here as helping hand to ensure reliable and effective operation.

Prahalad Rai
9669776202
RNB Infotech, Gwalior