Saturday, January 26, 2008

Reclaiming heat energy

Today we pay for the power to the data center twice. First to power the racks, then to remove the heat from the building via HVAC. A new technology from Berkeley Labs is intriguing, a more efficient means of turning a heat differential into power.

The explanation is confused, I am pretty sure that Berkeley does not beleive it has found a way to break the second law of thermodynamics as one might imagine from the article. If energy is extracted from the system the hot region must get cooler and the cool region hotter.

Another way to achieve the same effect would be through a steam turbine. This is done in power stations today. In principle one could use a steam turbine to extract energy from a data center without getting up to the boiling point of water by using a liquid with a lower boiling point and operating it at lower pressure. This was investigated by the chemical industry during the 1970s oil price shock but abandonded because their low grade heat sources tended to be contaminated by corosive chemicals. One plant I worked on in the 1980s that made neoprene precursors was continuously disolving its infrastructure.

Now that extracting waste heat from data centers is becomming a major concern I expect new interest in these technologies. Pretty soon we will be seeing heat pipe technology integrated into equipment racks as a matter of course. Why give the energy way when you can recover some of it?

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