MACE: Microtechnologies for Air-Cooled Exchangers

As electronic system technology advances – with continual increases in requirements leading to increasing demand for higher power consumption – there has been increasing pressure on the thermal engineering and heat rejection technologies used. DoD systems are driving conflicting needs for high performance as well as reduced size and weight. 

DARPA makes many investments in new technologies that can improve performance or reduce size and weight. Unfortunately, in many cases, the power consumption of these systems increases with each improvement. 

As a result, the performance of the heat rejection technology has become a dominant limitation in many applications. 

Over the past 40 years, CMOS, telecommunications, active sensing and imaging and other technologies have undergone tremendous technological innovation. Over this same historical period, the technologies, designs, and performance of air-cooled heat exchangers have remained unchanged. 

Because of the improved performance, and the increased power consumption of these DoD systems, heat rejection systems have grown in size, weight, complexity, and cost. Where conventional air-cooled heat sinks have become inadequate, more exotic liquid-cooled manifolds, spray-cooled enclosures, and vapor-compression refrigeration have been introduced. 

All of these cooling approaches bring added complexity associated with the operation of the active pumps and compressors, concerns over prevention of fluid or vapor leakage, long-term reliability, and many other factors that increase the cost of the systems. In many of these cases, it is much easier to supply forced air to the components to be cooled, and system designers would quickly return to the use of air cooling if the performance (thermal resistance, operating power) could meet other requirements. 

A successful MACE program will allow some high-performance DoD systems to replace the exotic cooling technologies with simpler, less-expensive air-cooled exchangers.