This paper was presented at the 4th Micro and Nano Flows Conference (MNF2014), which was held at University College, London, UK. The conference was organised by Brunel University and supported by the Italian Union of Thermofluiddynamics, IPEM, the Process Intensification Network, the Institution of Mechanical Engineers, the Heat Transfer Society, HEXAG - the Heat Exchange Action Group, and the Energy Institute, ASME Press, LCN London Centre for Nanotechnology, UCL University College London, UCL Engineering, the International NanoScience Community, www.nanopaprika.eu.A characterization of gas-to-gas micro heat exchangers has been performed in terms of pressure
drop behavior and heat transfer performance. The gas-to-gas micro heat exchangers differ by partition wall
material, partition wall thickness and flow arrangement. The pressure drop behavior has been analyzed due
to the pressure losses in different sections of the gas-to-gas micro heat exchangers. Increased pressure losses
in front of and behind the micro channels have been detected due to modified geometries in the inlet and
outlet distribution chambers. The heat transfer performance has been determined in terms of thermal
effectiveness. The comparison among different partition wall materials and partition wall thicknesses showed
no significant criteria of the influence of thermal conductivity on the thermal effectiveness. An assessment
due to an overall heat exchanger effectiveness has been performed to compare the gas-to-gas micro heat
exchangers. For this purpose, the overall exergy loss has been calculated by combination of thermal
effectiveness and pressure losses. A strong impact of the exergy loss due to pressure drop has been detected
which influences the overall exergy loss of the gas-to-gas micro heat exchangers
