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09.08.2007 - Counting Molecules In The Heat
Counting Molecules In The Heat A new law of heat-transfer has been identified in a modulated Rayleigh-Bénard chamber, using a novel technique for measuring micro-Kelvin temperature gradients at room temperature. This sensitivity corresponds to measuring color differences with a resolution of 10 parts per billion, or tracking differences in (linear) fluid motion down to a thousand molecules per second.

Expressed in a novel Nusselt number, heat-transfer to external flow passing through a Rayleigh-Bénard chamber is found to be linear at lowReynolds numbers. This behavior is completely different from the singular response in the boundary layer theory of L.V. King (1914), and it opens new possibilities for digital measurement of fluid flow. We report on a contemporary application of monitoring residential gas energy-usage in real-time, to visualize daily energy usage in taking showers, baking eggs and washing hands.
The same data can be analyzed in correlation with local weather to measure home energy efficiency.

van Putten, M.H.P.M., and van Putten, A.F.P., 2007, Proc. Royal Soc. London A, 10.1098/rspa.2007.1894 www.journals.royalsoc.ac.uk


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