Sage-Tips

How do you calculate evaporation losses in a cooling tower?

Evaporation Loss This means T1 – T2 = inlet water temperature minus outlet water temperature (°F), with 0.00085 being an evaporation constant.

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 much water does cooling tower lose to evaporation?

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.

How do you calculate the blowdown of a cooling tower?

It is calculated by this equation:

1. Evaporation loss = 0.00085 Wc (T1-T2)
2. Drift loss = 0.02\% water supply [for new development in eliminator design]
3. Blowdown = [ Evaporative loss – (COC – 1) x Drift loss] /(COC – 1)

What is drift losses in cooling tower?

Drift is water lost from cooling towers as liquid droplets are entrained in the exhaust air. The drift loss is independent of the water lost by evaporation and may be expressed in units of lb/hr or percentage of circulating water flow. Cooling tower drift eliminators are used to control this drift loss from the tower.

How do you calculate evaporation loss in a reservoir?

In this method the evaporation is determined by the equation : E = P+I-O+U+S, where, E = evaporation P = precipitation on the water surface I = surface inflow O = surface outflow U = underground inflow or outflow and S = change in storage.

How do you calculate the efficiency of a cooling tower?

Cooling Tower Efficiency Calculations

1. Approach = Cold Water Temperature – Wet Bulb Temperature.
2. Cooling Tower Efficiency =
3. (Hot Water Temperature – Cold water Temperature) x 100/
4. (Hot Water Temperature – Wet bulb temperature)

How does a cooling tower lose water?

The cooled water pools in the bottom of the tower, where it gets recirculated back into your industrial equipment or air conditioning system. Throughout this process, wet cooling towers lose water in three ways: evaporation, drift (also called “windage”), and blow-down (also called “draw-off”).

How is cooling tower capacity calculated?

This should be expressed in Fahrenheit and is denoted as dt in the formula. Multiply 500 times the water flow rate, times the temperature difference, divided by 12,000 or 500 x q x dt/12,000. The result is the tons of capacity of the cooling tower.

How do you calculate the effectiveness of a cooling tower?

Cooling Tower Thermal Efficiency Calculations

1. Approach = Cold Water Temperature – Wet Bulb Temperature.
2. Range = Hot Water Temperature – Cold Water Temperature.
3. Cooling Tower Thermal Efficiency = Range/ (Range + Approach) x 100.
4. COC = Silica in Cooling Water / Silica in Makeup Water.

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.

What are the losses in a cooling tower?

One of the types of loss is drift loss in a cooling tower or windage. Drift loss is considered a function of drift eliminator design and is considered to be: Drift loss (D) = 0.3 to 1.0 percent of circulating water (C) for a natural draft tower Drift loss (D) = 0.1 to 0.2 percent of circulating water (C) for a typical induced draft tower

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.

Does a cooling tower require treatment?

Proper water treatment in your cooling tower system is required to minimize the risk of corrosion, scaling, and microbiological buildup. These issues can reduce plant productivity, cause unplanned downtime, and require costly equipment replacements if conditions get out of control.