Panel Mounted AC or Window AC

What you need to be careful with, is that you don't cool your panel below the dew point at your location. Below the dew point condensation will collect on all metal surfaces inside your panel. If you use a window air conditioner make sure it is set to recirculate the air inside the panel. That way you won't be introducing humidity from outside the panel.

The method you use to cool your panel really doesn't matter. The temperature being kept above the dew point, does matter.

Please ensure that condensate tray of the window A.C is connected to the proper drain line. It is installed properly so that accumulated water in the condensate tray will not pass in to the room. Regularly check the filters of the A.C . Do not keep the inside condition of the room too low. Avoid fresh air leakage to avoid condensation on the surface of the panels.

Elroy is correct when he states that you run the risk of condensation in the panel. If these are 134a units, the refrigerant fractionates starting about 105f ambient to the point of rapid capacity loss. Much better to subcool the liquid line just before tor cap tube or txv. Common approach would be water cooling with regulating valve. If these are r12 units, the same solution will satisfy. Ideal condensing temperature is about 85f. The panel cooling units lower your rh in the panel and will not cause condensation. This is a common problem because the design engineers have apparently never worked in a plant where the process raises the ambient temp and moisture levels. Sealing your panels better often help because the dryer air inside acts like a sponge and draws more humidity in. This causes more of your capacity to be wasted on latent load as opposed to sensible.

pls check Bard A/C unit(see website for more info) - its compact and relieble - we are using it at our District Cooling Plant from UAE, Qatar, Kuwait, Oman and other GCC country with no complaint so far.