RoboRunner to the rescue
Sensing heat is also a priority in a datacenter, where racks and racks of computers are stored. Although data centers are built on raised floors which circulate cool air, each rack vents its waste heat out the back of each rack, creating a "hot spot". If those hot spots arent constantly monitored, the heated air could be sucked into the cooling vent of another rackoverheating the processor, shutting down the rack, and costing the datacenter and customer money. Datacenters already spend 10 percent of their power budgetabout $1 million a year -- on cooling alone. "Today, the state of the art in datacenter cooling is an engineer walking around and feeling the heat," Patel said. "If it feels too hot, he turns up the air conditioner. Thats state of the art. "Now what were proposing is to replace this technician with a robot that rolls around the aisles, into tight spaces and maps the temperature in the X, Y, and Z [height] direction," Patel added.A separate server receives the data and plots hot spots, which HP is developing and testing. In the future, HP hopes that it or another firm can design louvered floor vents that can detect cool air to where its needed. "Controlled cooling is a smart cooling proposition," Patel said. HPs cooling labs already examine other ways off cooling rack-mounted systems, Sharma said, who noted that its budget hasnt suffered even through the HP-Compaq merger and subsequent cost-cutting. "Our CEO has said that datacenters are a priority," he said. HP has looked at three technologies to cool its Vectra line of servers: a thermal actuator, or liquid heat exchanger; a plane roll bond panel containing liquid; and a thermosyphon, an advanced heat pipe. The thermal actuator pushes a "cold plate" against the processor with thermal grease or some other substance. A plane roll bond is actually a flat radiator-like plate mounted on the wall of the server, which circulates a 60% glycol/40% water solution through buoyancy-induced convection, eliminating the need for fans. Thermosyphons funnel fluid from the outside condenser to the evaporator on top of the microprocessor. But HP discarded thermosyphons, and heat pipes, because of "pulse boiling", a rapid cycle of heating and cooling that can damage the microprocessor, according to an internal study conducted in May of 2000. HP developed its evaporative cooling to eliminate "pulse boiling," Patel said. HP holds two patents on the "inkjet" evaporative cooling methods, and ten on the robotic monitoring system. HP might not mind licensing the technology, although it was developed for internal purposes, Patel said. The inkjet technology could be available in three years, executives said, while the smart datacenter could be only two years out. The robot might just need a year of polishing. HPs corporate envisions datacenters scattered all over the world. If thermal concerns were the only issue, Patel said, datacenter managers could shift their workloads to, say, Alaska, where cooling isnt usually a problem. "We need to think of energy management and shift workloads around globally," he said. Note: the following corrections were made to the previous version of the story:
The robot is relatively simple. HP bought a robot from a third-party manufacturer, hooked up a laptop computer, and attached a pole with several temperature sensors. The "RoboRunner" wanders around the datacenter on a preprogrammed course, taking temperature readings at predetermined points. The robot did have to be manually driven around the lap to map the area, but engineers said the process only took about an hour.
- At IDF on Sept. 9th, Patel is expected to give a presentation on the importance of data center cooling. (Changed from "multiprocessor cooling".)
- Evaporative cooling can dissipate up to 100 watts, or heat densities of 200 watts per square centimeter. (Changed from "20 watts".)
- In an HP chip, "we had to fight to just get one (diode)," he said. "They screamed." (Changed from "Itanium chip".)