A novel mechanism for thermal management at the cold side of a pulsed two-stage thermoelectric micro-cooler with different PCM heat sink shapes

A new mechanism for thermal management at the cold side of a pulsed two-stage thermoelectric micro-cooler (Two-stage μTEC) is presented. The Two-stage μTEC operates under different electric current values at each stage and uses a phase change material (PCM) in different heat sink shapes for temperature control in the cold junction. A geometric factor γ is defined for designing an optimal heat sink based on reducing the cross-sectional area of the second stage thermoelements. The aim is to save the amount of PCM used and keep the cold side temperature (T_c) constant for as long as possible. This thermoelectric device is proposed to treat skin diseases and is suitable for use in cryomassage. A one-dimensional numerical model is considered in the system's heat transfer, and cooling by natural convection on the hot side is considered. PCM is used as a cooling substance because it can absorb large amounts of latent heat at a nearly constant temperature. The influence of the electric current pulse and the γ geometric relationship on the micro-cooler are analyzed to determine the optimum operating values that allow a constant temperature of 243 K to be reached in the cold junction. The temperature of the cold side is kept constant by using different electric currents in each stage for the geometric factor γ=4 during Δt_pulse=95.7s.