Supercooling in a new two-stage thermoelectric cooler design with phase change material and Thomson effect

• Published in: Energy conversion and management 2021-09, Vol.243, p.114355, Article 114355
• Main Authors: Ruiz-Ortega, Pablo Eduardo, Olivares-Robles, Miguel Angel, Enciso-Montes de Oca, Olao Yair
• Format: Article
• Language: English
• Subjects: Coolers; Cooling; Geometry; Heat; Heat sinks; Heat transfer; Melt temperature; Metal strips; Numerical analysis; Peltier; Performance enhancement; Phase change material; Phase change materials; Pulsed current; Supercooling; Temperature profiles; Thermoelectric; Thermoelectric cooling
• ISSN: 0196-8904; 1879-2227
• DOI: 10.1016/j.enconman.2021.114355

[Display omitted] •Develop of a new two-stage model design with phase change material for pulse operation.•New approach to find thermal characteristics for maximum temperature drop in thermoelectric coolers.•Analysis considering metal strips and the ceramic plates for more realistic results.•Thomson effect and phase change material impact on thermoelectric cooling performance. A novel physical model of a two-stage thermoelectric cooler (TEC) is developed, based on geometry factor (γ) analysis between stages under pulsed current conditions and with phase change material (PCM), to improve performance. A detailed investigation of a two-stage Peltier cooler based on a general thermodynamic formulation considering the Thomson effect is presented. The minimum cold side temperature, coefficient of performance (COP), and further the thermoelement’s characteristic temperature profiles are discussed. The numerical analysis was carried out considering square pulse current, hot side heat transfer, metal strips, ceramic plates, and a PCM material volume in the heat sink. The investigation results proved that the geometry relation between both stages and the Thomson effect directly impacts supercooling, and a higher reduction in the cold side temperature can be achieved compared with conventional thermoelectric coolers. A reduction of 25.2 K in a two-stage over a single-stage TEC with PCM is achieved considering a large cross-sectional area in the first stage. It has been found that the holding time and the characteristic temperature profiles during and after pulse operation depends strongly on Thomson heat and geometry. A shorter holding time and maximum temperature drop are found for γ>1 values due to the PCM’s melting temperature and the higher pulse current. The characteristic cooling length reveals the part of the semiconductor element that is cooled during pulse operation. Results will guide the design or selection of a heat sink crucial to a solid-state cooling device’s overall performance.