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Green Revolution Cooling says that its systems contain 1,200 times more heat retention than air, which lets its GreenDEF liquid coolant cool servers at 40°C (104°F) and greatly reduce air conditioning costs which usually need to keep temperatures at 24°C (75°F).
Here's another look at a quad at CGGVeritas.
Here's a quad installed in a different room at CGGVeritas.
The racks are built so it's easy to lift the top. The coolant will not evaporate or spoil.