Classical linear thermoacoustic theory is applied to compact micro heat exchangers and the validity of such calculus applied to micro scale is discussed. Expressions for the radial profiles and average values of the fluid axial velocity and temperature are demonstrated, formulations for first order friction and heat transfer coefficients of oscillating flows are deduced. It is shown how aerodynamic and thermal performances of a micro heat exchanger in pulsed flow regime can be characterized with three factors: a thermal characteristic time, an aerodynamic matrix of transfer and a thermal efficiency. The model proposed is devoted to design the micro heat exchangers of micro refrigerators dedicated to the cooling of electronic components. (c) 2005 Elsevier Ltd. All rights reserved.