Okay, 2 things for critical thinkers to consider:
1) Sandia's own diagram of the device shows it cooling a surface from 40C down to 25C. If that is what they chose as numbers for a diagram, then it is reasonable to assume that is predictive of what their real world expectations are. Perhaps the technology may not be quite so efficient when the temperatures are higher, say, that of a modern CPU which, before cooling, is going to be in the triple digits.
2) I think that people are assuming that this device will somehow cool better than current technologies. But nowhere do they claim that. Since when is the average gamer worried about the power consumption of the CPU cooler? Most would happily accept a CPU that sucks twice the power of anything currently on the market, as long as it keeps the CPU cooler. Sandia only claims their design will cool more efficiently, i.e., at a lower cost - and perhaps only within the hinted at sweet spot of 45 degrees Celsius.