The Purdue team was able to develop an analytical model that paved the way for designing such miniature compressor and evaporator pumps. And the innovation is badly needed, because tomorrow’s blazing-fast microprocessors will kick out high degrees of heat that can damage chips' circuitry. Today’s computer chips generate something on the order of 100 watts per square centimeter, running millions of calculations per second. Faster microprocessors have delivered the performance promised by Moore’s Law but outpaced the ability of cooling fans and fins to dissipate heat. New chips are expected to increase ten-fold in heat output over the next few years. The Purdue group is designing miniature compressors and evaporators, which are critical for refrigeration systems. Their elastic membranes are made of ultra-thin sheets of a plastic called polyimide. And the plastic film is coated with metallic layer that conducts electricity. Hence, when electricity is sent through the metal layer, the diaphragm can move back and forth to produce a pumping action researchers call "electrostatic diaphragm compression." Experimental triumph is one significant accomplishment, but manufacturing the devices at an affordable low price point of $30 per system will surely be challenging. On the same campus in West Layafette, Indiana, another research group has developed a unique microjet technology, which uses liquid capable of carrying away five times more heat than the competing technologies, which use 200 watts per square centimeter of chip.
Microjet technologies have been around for some time, but Purdue’s team employs a liquid coolant called hydrofluorocarbon. Its unique property is that it doesn’t conduct electricity, a property that causes shorted circuits. The design of the microfluid system consists of grooves a millimeter in width. These microfluid channels are formed on top of a chip, where they’re covered with a metal plate containing tiny holes. The coolant is pumped through the holes, then flows along channels where it takes on heat. The fluid bubbles and becomes a vapor, thus transferring heat and cooling the area. The research was funded by the U.S. Office of Naval Research for several potential applications like advanced radar, propulsion systems and lasers. More efficient heat pumps and advanced heating and cooling are not an opportunity only in microelectronics. Integration of systems is considered one of the biggest areas of innovation being discussed amongst engineers these days, says Eckhard Groll, a Purdue professor of mechanical engineering. For the inefficient designs of home and business air conditioning systems, which result in wasted energy release, that could mean re-capturing heat released into the air by a cooling unit. The heat could then be used to heat water for household purposes. The specter of heat and energy costs is also a big concern for corporations. In fact, one in five corporate respondents in a recent Changewave Research survey indicated they were becoming much more concerned about improving energy efficiency within their businesses than in the past few years. Among the most important technologies to improve energy efficiency equation are solar power and LED lighting. One in five said they would be installing alternative energy systems like solar and wind within the next five years. Sure, it’s unlikely to see solar technologies appear in tomorrow’s laptops, but the push to innovate within computers will surely influence other large scale applications designed for buildings and homes.