Investigation of Heat-Dissipation Efficiency and Thermal Deformation of TECs with SWCNT Coated Heat Sink

• Main Authors: Lin, Jia-Ru, 林佳儒
• Other Authors: Wang, Wei-Chung
• Format: Others
• Language: zh-TW
• Published: 2017
• Online Access: http://ndltd.ncl.edu.tw/handle/4qpq7w

碩士 === 國立清華大學 === 動力機械工程學系 === 106 === Thermoelectric cooler (TEC) is a device which converts electrical energy into heat energy. The primary principle of the TEC is the Peltier effect. Thermoelectric cooler is a sandwich structure consisting of many different materials. When a direct current is applied, thermal stress and thermal deformation are unavoidably produced in the TEC due to the temperature gradient. Moreover, due to the mismatch of thermal expansion coefficient between component materials of the TEC, the TEC may be out of work after an extended period of practice. In this thesis, two sets of three dimensional digital image correlation (3D-DIC) systems were adopted to measure the deformation of two different TECs, i.e. TEC_A and TEC_B, of 127 pairs of p-type and n-type semiconductors with and without the heat sink, respectively. Strains of the TEC under different currents were measured, and the quality of the TEC was investigated by the strain and temperature distributions. Results showed that the strain becomes higher as the current increased. The quality of TEC_B was also found better based on results of the strain distribution. To enhance the cooling effect, single-walled carbon nanotube (SWCNT) was used to coat on the surface of the heat sink, and the cooling effect of the heat sink was found successfully improved. The strain of the TEC is smaller when the SWCNT heat sink was added, and the overall temperature distribution was also decreased. In the future, it is possible to use the SWCNT heat sink to replace the cooling fan for TECs under low and medium current. In addition to increase the service life of TECs, cost and the vibration produced from the cooling fan can also be reduced.