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Theoretical and experimental study of a thermal damper based on a CNT/PCM composite structure for transient electronic cooling. Energy Conversion and Management, Elsevier, 2017, 142, pp.257-271 AbstractThe present study focuses on a thermal damper that aims at smoothing the temperature peaks experienced by electronic components during transient solicitations. It consists of a silicon casing containing a densified or undensified carbon nanotube (CNT) array -linking directly both sides of the system -filled with phase change material (PCM). Theoretical consideration enables to define the concept of ideal thermal damper in order to study the foreseeable performance of this kind of system. Its thermal effectiveness can be predicted by means of two non-dimensional numbers, linked to the thermal capacity of the system and to the latent heat of the PCM. A numerical model shows that the behavior of a non-ideal thermal damper can differ from that of an ideal thermal damper: it is mostly affected by the thermal resistance at the interface between the silicon and the CNT and the temperature glide during the PCM phase change. To complete the study, prototypes of thermal dampers are experimentally characterized, in terms of heat storage and heat conduction performance. An estimation method of the total apparent thermal capacity of the tested sample is developed in order to quantify its latent heat storage capacity. The latent energy storage density is 1.6 J cm -2 for the best sample and is observed to be preserved after 850 thermal cycles. The total thermal resistance of the thermal damper is estimated by means of a laser flash test and a simple model of the sample. Sensitivity analyses show that the main thermal resistances are located at the interfaces between silicon and CNT.Keywords: vertically aligned carbon nanotubes, phase change material, thermal energy storage, interfacial thermal resistance, transient electronic cooling Highlights: Two non-dimensional parameters enabling to design an ideal thermal damper are identified  Latent energy storage capacity of embedded PCM is estimated and reaches 1.6 J cm -²

This paper presents the development of doped polycrystalline Si-SiGe superlattices as thermoelectric (TE) elements integrated into generators. The modules dimension is 1 cm 2 , Si and SiGe are in situ doped (n and p types) and realized by CVD (chemical vapor deposition) on a 4 inch (0 0 1) silicon wafer. Si-SiGe superlattice growth will be studied, as well as the integration into thermoelectric modules. Interest in using superlattices as TE materials will be justified by their thermal conductivity measurements. Moreover, process fabrication and different geometry designs will be presented. Finally, the first measurements realized on these modules allowed scavenging 320 mV for a temperature difference of 90 K.

This paper presents new devices to scavenge energy by developing a miniature power source for operating electronic components. Following our development of 2D thermoelectric devices [1], we conceived new processes and technology steps to develop 3D devices.Thermoelectric (TE) devices are realized with bismuth and antimony layers. These two elements are deposited by PVD (Physical Vapour Deposition). Bi and Sb micro-devices have been manufactured with an area of 1 cm 2 , including more than 63000 junctions. Each step of process fabrication has been optimized and will be presented. Different devices structures have been realized. Thus each devices performance will be reviewed and estimated as a function of their structure design.