Evaporative Cooler Size Guide

How Much Evaporative Cooling?

size range  - Evaporative Cooler Size Guide

Small one or big one – perhaps something in between, or even several evaporative coolers

Evaporative cooling flow rate, i.e. the airflow, required for effective evaporative cooling is specified according the building type and its volume in m3.  When sizing a system we do not always take the complete building volume but do take the effective cooled volume which would for example exclude the air space above the ducts if the ducted cool air is to be introduced at a high level and directed down. Different types of building use demand different amounts of cooling. The following table is essentially an evaporative cooler size guide which expresses the range of air changes that are required by evaporative cooling in different application types, in order to effectively cool the building.

Building usage Air changes base on cooling using 50mm panels Air changes base on cooling using 100mm panels
Textile industries 25-29 22-26
Rag workshops 22-25 20-22
Machine rooms 18-22 16-20
Manufacturing trade 18-22 16-20
Foundries 25-30 22-27
Painting workshops 25-30 22-27
Plastic manufactures 30-35 27-31
Bakeries 20-25 18-22
Restaurants 18-22 16-20
Cafes and bars 18-22 16-20
Canteens 18-22 16-20
Entertainment Halls 25-29 22-26
Wine cellars 30-40 27-36
Discotheques and pubs 25-29 22-26
Cinemas and theatres 14-18 13-16


Multiply the effective cooled volume by the air change rate to get the total airflow in m3/hr.  This is the airflow that the evaporative cooler needs to achieve. If you have a large or complex building it may make sense to break down the volume into zones or sections. Each zone or section might have particular features which will influence the choice of air change rate, such as activity type or anticipated supply ducting height.

Having used this evaporative cooler size guide the next stage is to choose your evaporative cooler.  If you have come up with a large airflow that will require a number of evaporative coolers then please read through our guide to evaporative cooler sizes, before taking the plunge because it might open your eyes about the potential needless extra costs that can go with the wrong choice. You may want to give us a call so that we can help you fine tune the selection of unit(s). Once we have decided which units to use we can calculate the anticipated performance of the evaporative coolers in your application.

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