Just purchase and installed a Dell Powerconnect 8182 10 GB Copper Switch. Periodically the fans will increase in speed for about 1 to 1.5 hours, then they'll go back to "normal". The rack is located in my office and when the fan speed increases it's pretty loud.
I checked the health of the switch during this increased fan speed period and all the heat sensors are "good" except the MAC temperature sensor which indicates "Medium".
I have a Daikin Split Air Conditioner that keeps my office right around 70 degrees. I even have it blowing almost directly into the switch front so it should be running cool.
Additionally I have a Sonicwall 3500 located just under the switch. Tomorrow, I'm going to remove it to see if it helps. I'm fearing the Sonicwall top cover is getting warm and transferring heat to the bottom of the switch.
I have never had an "advanced" switch - we only have had Dell Powerconnect 2624 & 2824 - simple switches.
Is this high fan speed condition normal with advanced switches? (Anyone have a Dell 8132 ???) Called Dell - they aren't too concerned... I feel like I'm on a commercial airliner!