Thermal imaging of microfluidic systems as a model for investigating energy efficiency

We explore the use of a commercial thermal imaging infrared camera (7-12 micron, uncooled microbolometer array, 320 x 240 resolution) to characterize microfluidic devices with the aims of: 1) evaluating the usefulness of thermal imaging to assess various flow configurations with respect to heat transfer, and 2) developing educational laboratory projects combining rapid prototyping, thermal imaging, microfluidics, and heat transfer. We investigated concurrent and countercurrent heat exchangers, mixing streams of different temperature (cold and hot water), mixing streams yielding a heat of mixing (ethanol and water), mixing streams yielding a heat of reaction (acid-base neutralization), and freezing and heating flowing streams in channels with a Peltier module. Energy efficiency can be assessed to determine the feasibility and effectiveness of microfluidic designs. Substantial improvements in mixing and heat transfer using a magnetic stirrer are demonstrated with thermal imaging.