Abstract
The thermoelectric chips can convert heat into electricity and vice versa. So they can be used as power generators, waste heat recovery systems, refrigerators and air conditoners. The nowadays commercial thermoelectric materials are rare and expensive. Therefore, in this thesis we choose common materials like silicon, germanium and conductive polymer as thermoelectric chips in which we use computational quantum mechanics to find their DOS (Density of States) and band structures. BTE (Boltzmann Transport Equation) is then introduced to calculate the electrical properties of the nanostructures, such as Seebeck coefficient, electrical conductivity and electron thermal conductivity. DFPT (Density Functional Perturbation Theory) is used to simulate the phonon DOS and dispersion relation of the semiconductor and conductive polymer nanowires, which can be used to calculate the phonon group velocity, heat capacity and mean free path. Next, we obtain the phonon thermal conductivity of the nanostructures under phonon gas model. After we predict the electrical and thermal properties of the nanowires, we can calculate their figure of merit (ZT). Improved doping poly-p-phenylene (PPP) nanowire is then chosen to design the thermoelectric chip air conditioner because it has the highest ZT. The coefficient of performance (COP) and temperature dynamics of an electric vehicle’s cabin is calculated. The energy losses of power converters we used are minimized under the Euler-Lagrange (EL) framework. In conclusion, novel PPP-based thermoelectric chip air conditioner will be a potential air conditioner candidate for future electric vehicles since it is able to increase mileage and improve climate control.