Strategies of simulating cooling systems with heat pipes and TEC devices

S. Lin, J. Broadbent, R. McGlen

Thermacore Europe, 12 Wansbeck Business Park

Ashington, Northumberland, NE63 8QW, UK

Thermoelectric cooling, also called "the Peltier Effect," is a solid-state method of heat transfer through dissimilar semiconductor materials. In a thermoelectric refrigeration system, the three main working parts are a cold junction, a heat sink and a DC power source. The cold junction becomes cold through absorption of energy by the electrons as they pass from one semiconductor to another. The DC power source pumps the electrons from one semiconductor to another. A heat sink discharges the accumulated heat energy from the system.

Good thermoelectric semiconductor materials, such as bismuth telluride, greatly impede conventional heat conduction from hot to cold junction, and provide an easy flow for the carriers. In addition, these materials have carriers with a capacity for transferring more heat. Thermoelectric materials are also of interest for applications as heat pumps and power generators. However, the performance of the heat sink is a very important aspect of a good thermoelectric system.

In microelectronics, telecommunications and power electronics thermal management, heat pipe technology has found its increasing applications in enhancing the thermal performance of heat sinks. Heat pipes, as two-phase heat transfer devices with extremely high effective thermal conductivity. They can be cylindrical or planar in structure. Heat pipes can also be embedded in a metal cooling plate, which is attached to the electronic component. Due to the high heat transport capacity, heat sinks with heat pipes have become much smaller than traditional extruded fins in handling high heat fluxes. With the working fluid in a heat pipe, heat can be absorbed on the evaporator region and transported to the condenser region where the vapour condenses releasing the heat to the cooling media.

Thus utilisation of heat pipes in thermoelectric systems may lead to a significant enhancement of the system thermal performance. However, the design of thermoelectric system with heat pipes still meets number of challenges. This paper presents a design method by using CFD simulation of thermoelectric device with embedded heat pipes. The strategies of simulating thermoelectric coupled with heat pipe simulation are presented. The calculated results are also compared with the experimental results. The study suggests that the CFD model is able to predict thermal performance of the thermoelectric devices with heat pipes and thus can be used in the system design.