4Properly Sizing Your Application
Conducting a sizing will help you accurately determine how much cooling is required for your application. Accurate sizing is more than a simple watt to BTU conversion and consists of a combination of factors.
Implementing the correct solution to maintain a temperature-controlled operating environment is essential to protecting your equipment. Providing accurate measurements, not overestimating ambient temperatures, and selecting an appropriate Delta T will help you achieve the most accurate sizing results. A cooling system that is too large uses an unnecessary amount of energy and can be more costly. Too small of a system will degrade the life cycle of the air conditioner and could potentially result in repairs, a need for supplemental cooling, or failure of the very equipment that is being protected. Correctly sizing a cooling system will ensure your equipment will run efficiently and reduce downtime, energy costs and repairs.
Step 1: Accurate Maximum Ambient Temperature
First, determine an accurate maximum ambient temperature where the enclosure is located. Then select an acceptable maximum desired internal temperature.
For more info on calculating the ambient temperature in different environments, check out our Ambient Temperature Guide.
Indicate the maximum ambient temperature to be experienced where the A/C will be installed. Do not use an excessively high temperature to create a “safety margin” or measure surface temperature as this will result in an oversized air conditioner. Provide ONLY the realistic maximum air temperature.
The Dangers of Selecting an Extremely Low Internal Temperature
The acceptable internal temperature is based on your equipment’s maximum operating temperature. Using a “worst-case” ambient and a “best case” internal is not advised as creating an extreme difference between ambient and internal temperatures will result in an oversized air conditioner.
Knowing the total heat load of your application is the critical first step when choosing a cooling system that will achieve your goals.
Heat load refers to the amount of heat energy to be removed from a space to achieve a desired temperature within the space. There are three types of heat load you must consider when calculating the total heat load in an application:
- External heat load
- Solar load/gain
- Internal heat load
Provide internal heat load estimate in watts or BTUs (1 wat=3.412 BTUs). This is the heat being dissipated by the equipment housed inside the enclosure, usually measured in watts. This step is crucial to determine which cooling solution will meet your requirements. Instructions on how to determine the internal heat load are available in our Guide to Understanding Heat Load.
Step 2: Identify Enclosure Dimensions, Location, and Insulation
Height, Width and Depth will provide the surface area of the enclosure that needs to be cooled. The enclosure measurements must be in feet when using the EIC Solutions sizing equation.
Indicate if the enclosure is indoors or outdoors. If it is an outdoor enclosure that is in full or partial sun, you must know the color of the enclosure. The color of an enclosure will have a direct effect on the amount of heat generated from the solar load. You must account for the solar heat load to size correctly.
Determine if the enclosure is insulated and provide R Value of insulation. The higher the R Value the better the insulation material’s ability to resist the flow of heat through it. If your enclosure is not insulated, the R Value is 0.
Step 3: Size Application for Cooling Requirement
***Disclaimer: EIC Solutions Inc. assumes no responsibility for customer-run sizing results. This sizing equation is intended as a tool. The cooling results supplied by this sizing equation are believed to be accurate, however, it is the responsibility of the user to confirm the results are correct for their specific application. Any purchase made from sizing results not provided by an EIC solutions sales engineer are subject to our normal terms and conditions***