Engineering ToolBox - Resources, Tools and Basic Information for Engineering and Design of Technical Applications!

Cooling Tower Efficiency

Maximum cooling tower efficiency is limited by the cooling air wet-bulb temperature.

Sponsored Links

A cooling tower use evaporative cooling to reduce the temperature of circulated water, and

  • they can achieve water temperatures below the dry bulb temperature - tdb - of the cooling air
  • they are in general smaller and cheaper for the same cooling loads than other cooling systems

Cooling tower

Cooling towers are rated in terms of approach and range, where

  • the approach is the difference in temperature between the cooled water temperature and the entering air wet bulb temperature - twb - temperature
  • the range is the temperature difference between the water inlet and water exit

Note! - for a cooling tower based on evaporative cooling the maximum cooling tower efficiency is limited by the wet bulb temperature of the cooling air.

Cooling Tower Efficiency

Cooling tower efficiency can be expressed as

μ = (ti - to) 100 / (ti - twb)                                  (1)

where

μ = cooling tower efficiency (%) - the common range is between 70 - 75%

ti = inlet temperature of water to the tower (oC, oF)

to = outlet temperature of water from the tower (oC, oF)

twb = wet bulb temperature of air (oC, oF)

The temperature difference between inlet and outlet water (ti - to) is normally in the range 10 - 15 oF.

The water consumption - or the amount of make up water - of a cooling tower is about 0.2-0.3 liter per minute and ton of refrigeration. Compared with the use and waste of city water the water consumption can be reduced with about 90 - 95%.

There are two main types of cooling towers

  • forced draught (using fans)
  • natural draught

Both types are based on evaporative cooling.

  • Natural draught cooling towers are more dependent on temperature gradients between air and water and the wind forces than forced draught cooling towers
  • The efficiency of natural draught towers are more variable over time and in general lower

Note! - be aware that a medium temperature system - like cooling a tower - are a known source of pathogenic bacteria causing the Legionnaires disease. Good cleaning and maintenance of the systems are important to minimize the risk.

Sponsored Links

Related Topics

Related Documents

Sponsored Links

Engineering ToolBox - SketchUp Extension - Online 3D modeling!

3D Engineering ToolBox Extension to SketchUp - add parametric components to your SketchUp model

Add standard and customized parametric components - like flange beams, lumbers, piping, stairs and more - to your Sketchup model with the Engineering ToolBox - SketchUp Extension - enabled for use with the amazing, fun and free SketchUp Make and SketchUp Pro .Add the Engineering ToolBox extension to your SketchUp from the SketchUp Pro Sketchup Extension Warehouse!

Translate
About the Engineering ToolBox!

Privacy

We don't collect information from our users. Only emails and answers are saved in our archive. Cookies are only used in the browser to improve user experience.

Some of our calculators and applications let you save application data to your local computer. These applications will - due to browser restrictions - send data between your browser and our server. We don't save this data.

Google use cookies for serving our ads and handling visitor statistics. Please read Google Privacy & Terms for more information about how you can control adserving and the information collected.

AddThis use cookies for handling links to social media. Please read AddThis Privacy for more information.

Citation

This page can be cited as

  • Engineering ToolBox, (2004). Cooling Tower Efficiency. [online] Available at: https://www.engineeringtoolbox.com/cooling-tower-efficiency-d_699.html [Accessed Day Mo. Year].

Modify access date.

. .

close

3D Engineering ToolBox - draw and model technical applications! 2D Engineering ToolBox - create and share online diagram drawing templates! Engineering ToolBox Apps - mobile online and offline engineering applications!

Scientific Online Calculator

Scientific Calculator

3 30

Sponsored Links
.