I was working with a customer the other day who had a control panel located in a very hot environment next to a steam turbine in a power plant. The panel already had a Cabinet Cooler System working to keep the internal space cooled. However, due to some faulty temperature data about the surrounding environment, the customer had underestimated the heat load required in the application. As a result, his control cabinet was running a little higher than he wanted it to in terms of temperature. His Target was 95°F but he was running a solid 105°F inside the cabinet.
After we discussed the application a bit further and he sent some photos of the Cabinet, I learned that there was a rather large, hot turbine, just inches away from this panel. I also determined that the customer had installed our Cabinet Cooler on the top of the panel and was feeding it with proper compressed air to allow it to work at full capacity.
This is where some thinking about other strategies when considering how to reduce heat load on a cabinet come into play. Namely, passive methods of adding insulation to the exterior of the panel as well as employing heat shields between the heat source and the cabinet. Both methods are good ways to passively reduce the amount of heat load that needs to be delivered from a Cabinet Cooler to the cabinet.
In this application, the customer not only insulated his whole panel, but also the in-coming compressed air line to keep the heat from the turbine from sinking in through the walls of the cabinet and the compressed air pipe. After he made the suggested changes, the customer was able to reduce his cabinet temperature by the needed 10°F to keep a safe, 95°F inside the cabinet.
Neal Raker, Application Engineer