How do you calculate the evaporation rate of a cooling tower?

How do you calculate the evaporation rate of a cooling tower?

Let’s calculate each component.

1. Evaporation loss = 0.00085 x 10 000 x (100-85) = 127.5 gpm.
2. Drift loss = 0.02% x 10 000 = 2 gpm.
3. Blowdown = [127.5 – (5-1) x 2]/(5-1) = 29.87 gpm.
4. Cooling tower makeup water = 127.5 + 2 +29.87 = 159.37 gpm.

How much water does cooling tower lose to evaporation?

1%
As air rises inside the tower, it receives the latent heat of vaporization from the water, and thus the water is cooled. As a rule of thumb, for every 10°F (5.5°C) of water cooling, 1% total mass of water is lost due to evaporation.

What is blowdown rate in cooling tower?

Before the concentration of these solids becomes too high, some of this water is removed and replaced with fresh water. This process is called blowdown, and blowdown loss is the amount of water lost during the blowdown process in your cooling tower.

How do you calculate evaporation loss?

To calculate evaporation losses, multiply the water surface area (in m2 ) by the corrected evaporation rate (in m) for the length of time your pond will be in use.

How does water evaporate in a cooling tower?

In the open cooling tower, the warm return water from the heat exchanger is sprayed over the “fill”. The fill provides the surface area to enhance the heat transfer between the water and air, causing a portion of the water to evaporate.

What is the efficiency of cooling tower?

In practice, the cooling tower efficiency will be in between 70 to 75%.

How do cooling towers reduce water loss?

There are frequently three ways to reduce water consumption in a cooling tower: 1) Changing wet cooling tower to hybrid or dry cooling tower, 2) Reduction in blowdown with increasing of concentration cycles and 3) Using air to air heat exchanger on the cooling tower.

Is evaporation a cooling process?

Evaporation causes cooling because the process requires heat energy. The energy is taken away by the molecules when they convert from liquid into gas, and this causes cooling on the original surface.

Do cooling towers evaporate water?

Traditional cooling towers can consume 2.4 gallons of water per minute of operation per 100 tons of cooling through evaporation (Vickers 2001). As cooling tower water evaporates, it leaves behind a concentration of dissolved solids including mineral deposits and other added process chemicals.

How do you Calculate evaporation in cooling tower?

The following is a simple formula for calculating the evaporation in a cooling tower. Take the number of gallons of circulating water per minute and multiply that by the difference between the temperature of the water in the top of the tower versus that bottom of the tower. The degrees should be in Fahrenheit.

How much does a cooling tower evaporate?

Cooling towers cool water by evaporating a small percentage of the recirculating water flow. In general, 0.1% of the recirculating water is evaporated for every 1 degree of temperature drop across the tower. It takes approximately 1000 Btu’s to evaporate 1 pound of water.

How does evaporation take place in a cooling tower?

Water evaporation takes place inside the cooling tower as water droplets get in touch with the air stream to cause the chilling of the remaining water, which is subsequently used as the cooling medium.

How much water do cooling towers routinely blow down?

A typical cooling tower (500 ton, running 24 hrs day. 365 days per year) will flush over 3.9 Million gallons of water down the drain each year. This breaks down to approximately 10,800 gallons of waste per day, 450 gallons per hour, or 7.5 gallons per minute being flushed down the drain from the cooling tower system 24 hours a day, 7 days a week.