Current state of Peltier cooling

The performances of Peltier cooling depend first of all, on the thermoelectric properties of the thermoelectric (TE) materials and secondly on the thermal design. A survey will be given of present and future TE materials, bulk and thin film. The technologies of manufacturing the materials and of manufacturing TE modules (a rigid assembly of TE couples) will be presented with future trends. Cooling systems from milliwatts to kilowatts with temperature differentials from a few K to more than 100 K will be examined. Present day and pending applications will be reviewed. The figure of merit Z is the best overall parameter to characterize TE material, We will examine, for a standard air-air modular cooling unit, the influence of higher values of Z, on the cooling power and the coefficient of performance COP (=cooling power/electrical power). Also the influence on the cost of the system will be estimated. The COP of TE is compared to the COP of a small HFC type compressor. The aspect of development cost will be addressed as it is a major drawback to the increase of new developments