Whether you have an existing electrical enclosure or are about to install a new one, it’s essential to identify the right enclosure cooling solution to ensure that the enclosure doesn’t overheat. The answer may be as simple as adding a few ventilation fans or it might be necessary to install an enclosure air conditioner. Here are six simple steps to finding the right solution.
1. Collect Relevant Information
If it’s an existing installation, find out what cooling has been fitted. In addition, for all enclosures establish the enclosure size, what equipment is installed and if there are any special factors that need to be taken into account, such as exposure to solar radiation, the need for protection against dust, dirt and pollution and whether the enclosure is indoors or outdoors.
2. Analyze the Heat Load
Ascertain the heat load inside the enclosure by calculating the amount of heat that’s generated by the equipment. Make a list of all equipment, paying particular attention to manufacturers’ model numbers. Use information from each manufacturer to look up how much heat, in watts, each item generates. The heat load is calculated by subtracting their efficiency from one and multiplying the result by the power consumed by the device. This represents the amount of power that is dissipated by the device. Be careful to get the correct information from the manufacturer because efficiency of individual types of equipment varies considerably.
3. Establish the Ambient and Enclosure Air Temperature Limits
Determine as accurately as possible the actual ambient temperature range in the enclosure’s location. It’s particularly important to understand how high the ambient temperature will be at the height of summer as this often represents the worst case scenario.
Also get hold of the maximum operating temperature rating of each item of equipment. The allowable enclosure temperature must be less than the lowest temperature rating and it’s good practice to decide on a temperature at least 10°F lower to avoid overstressing equipment. The most common maximum temperature used for an electrical enclosure is 95°F (35°C).
4. Calculate the Required Cooling Capacity
The next step is to determine how much cooling is required. To do this, it’s best to use an online Enclosure Temperature Management Calculator, although, if you are determined, it is possible to perform a manual calculation if you have access to appropriate factors. Some additional information is required, including the size of the enclosure, its material of construction, color and if it’s insulated. Enter the required information and choose one of the three calculator types. If you choose one that’s inappropriate, the calculator will not give you a result.
5. Decide on Enclosure Sealing
Before finalizing your choice of cooling solution, you need to decide whether you need to seal the enclosure or if it’s acceptable to use a ventilated enclosure. The choice depends on the amount of dust, dirt and other pollution that’s present as well as upon any specific environmental conditions, such as water spray, snow and ice. If the ambient temperature is higher than the desired enclosure temperature, a sealed enclosure will be needed. Based on that information, choose an appropriate NEMA enclosure rating for the enclosure and its cooling solution.
6. Choose the Appropriate Solution
There are three different cooling solutions to choose from, and the right choice will depend on several factors, as illustrated below:
- Filtered fans: If there are no environmental issues that prohibit the use of a ventilated enclosure, and as long as the chosen enclosure temperature is higher than the maximum ambient temperature, filtered fans represent an effective and economical choice. Filtered fan packages are available for NEMA Types 1 and 3R enclosures.
- Air to air heat exchanger: If the environmental conditions indicate that a sealed enclosure is a better choice, but you can still tolerate an enclosure temperature that’s higher than the ambient temperature, then an air to air heat exchanger is an excellent choice for moderate heat loads. These economical units can be supplied with NEMA Types 12, 4 or 4X enclosure ratings.
- Enclosure air conditioner: If the maximum enclosure temperature needs to be lower than the ambient temperature, an enclosure air conditioner is the only practical solution. Enclosure air conditioners are a closed loop cooling solution so the electrical enclosure will need to be sealed. Air conditioners have the added advantage of high cooling capacity so they are great for high-heat loads. Additionally, they are able to maintain a constant enclosure temperature regardless of outside conditions. Enclosure air conditioners are available to suit NEMA Types 12, 4 and 4X enclosures.
The many factors that can have an impact on enclosure cooling mean that it is not always easy to choose the right enclosure cooling solution. If you need guidance, our experienced Sales Team will take you through the selection process and help you make the right choice.