Will it damage my MacBook if I put it in the fridge to cool it down?

The concern isn't really when it's in the fridge but when you take it out. The cold laptop/parts will pull the water out of the air AFTER it's taken out of the fridge, even if it was in a plastic bag. Think of a glass of water, it doesn't 'sweat' when it's in the fridge but you take it out on a hot day and it does.

The other concern is, depending on the temperature difference you are creating, there will be some extra wear on the components from expanding/contracting of parts.

The only thing I can think of to recommend is getting one of the laptop 'docks' with a couple fans in it to help move the air around the laptop.

As you suspect, it is not a very good idea. The cooler air inside the fridge can quickly condense the vapor normally found in the air, producing little droplets of water on the coolest parts (such as the motherboard).

Even if you find it effective, it may result in damage to your computer. I simply suggest you not do it.

Read USGS website for more insight in the condensation process (it is mainly about cloud formation, so please focus on the "Condensation in the air" section).

As others already said, you're killing your laptop with the condensation. The water will usually not lead to a short circuit immediately, but instead lead to rust buildup first before the final shutdown after a couple times in the freezer.

Better solutions:

• You say the laptop is still under warranty: Use the warranty.
• Bottled air to clean the fans without opening the laptop /voiding the warranty.
• Laptop cooling pad. The ones with larger fans make less noise.