When attendees at yesterday's DataCenterDynamics 2007 conference in New York were asked whether they had implemented liquid cooling in their data center, only three hands when up. But Roger Schmidt, a Distinguished Engineer in IBM's Server Group, says there will be more very soon.
"In the New York area, multiple data centers are looking at including liquid cooling as an option," said Schmidt, who led a session on liquid cooling in Tuesday's event at the New York Hilton. Schmidt said many companies are "running out of room to ventilate racks in a data center. The next step is to put liquid cooling next to the rack. There's definitely improved energy efficiency, and it's a lot easier to pump liquid than to pump air to where it's needed."
The panel was part of a full day of information sessions at DataCenterDynamics, which was marking its fifth year in New York. The NYC show is one of 22 industry events DataCenterDynamics has on this year's schedule.
Schmidt heads the committee developing best practices for liquid cooling through ASHRAE, the global standards body for the HVAC industry. Schmidt's committee, known as TC9.9, recently published Liquid Cooling Guidelines for Datacom Equipment Centers. "The book incorporates the experience of liquid cooling from the mainframe days," says Schmidt. "Liquid cooling is a proven technology, and the book provides a good central source of liquid cooling information from the datacom equipment to the facility level."
In his session at DataCenterDynamics, Schmidt discussed some of the finer points of liquid cooling, including piping concerns and additional equipment requirements. "You have to worry about condensation, the dew point in the room, and the chemistry of the water," said Schmidt, who recommended using a corrosion inhibitor to coat copper piping, and the use of distilled water. Many systems also employ a cooling distribution unit (CDU), contributing another acronym to the industry glossary. "The CDU is a buffer in between the equipment and the chilled water system, providing flexibility with coolant and temperature control," said Schmidt.
It's been five years since cooling vendors began promoting liquid cooling products as the solution to rising heat loads in the data center. Those vendors have been proven correct in their prediction that high density hotspots would test the upper limits of air cooling capabilities. But despite widespread concern about heat loads and cooling costs, liquid cooling systems are widely discussed and lightly implemented. Schmidt believes that will change.
"You can't get enough airflow at the tile to satisfy the rack," he said. "You can't cool it properly, and what people are doing is not keeping their rack full."
An ongoing discussion point is "data center hydrophobia"