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Highlights • Studied the aerodynamic performance of disc-shaped wind rotor for small wind turbine. • Ranked the influence factors on power coefficient of the disc-shaped wind rotor. • Provided optimum parameter combination for the highest power coefficient of 0.467. • Studied the velocity field and wake characteristics under various parameters. Abstract A series of novel disc-shaped wind rotors used in the small-scale wind turbine are redesigned with the inspiration from the eco whisper turbine. The aerodynamic parameters such as power coefficient and torque coefficient are obtained by numerical simulation and wind tunnel test. The tip speed ratio, pitch angle and opening angle are taken into consideration to account for the influences on the power coefficient. The specific case with pitch angle of 30° and opening angle of 45° is tested in a wind tunnel and simulated with different turbulence models for Reynolds number in the range of 6.8 × 104–1.70 × 105, respectively. The results indicated that: (1) the numerical results based on the standard k - ω model agree well with the experimental results; (2) the orthogonal method shows the rank of influencing factors is pitch angle, opening angle and tip speed ratio, whose contributions to the power coefficient are about 66.36%, 18.53% and 11.43%, respectively; (3) the effects of both pitch angle and opening angle on power coefficient may be positive or negative, depending on the level of tip speed ratio; (4) as tip speed ratio increases, peak power coefficient can be achieved for an individual pitch angle or opening angle; (5) the value of tip speed ratio correspondent to the peak power coefficient decreases with decreasing pitch angle or opening angle; (6) the rotor with pitch angle of 20° and opening angle of 30° at a tip speed ratio of 1.4 provides the highest power coefficient of 0.47. The maximum power coefficient in the present paper is higher than most of the rotors in literature according to the comparison. [ABSTRACT FROM AUTHOR]

A TEG module with 199 thermoelectric (TE) couples was simulated with constant and variable property parameters respectively. It is indicated that the simulative results with variable property parameters are closer to the experimental results. Meanwhile, it is found that the open circuit voltage and output power are proportional to the number of TE couples. The parameterized rectangle-TEG(R-TEG) and circle-TEG(C-TEG) modules with 2 TE couples were established respectively; it was found that the performances of TEG have not relevant to the shape of TE couple. When the hot side temperature is constant, the internal resistance, the open circuit voltage and the efficiency increased but the output power decreased with the decrease of cross sectional area; when the cross sectional area is constant, the open circuit voltage, output power and efficiency increased with the increase of the hot side temperature. The intersection of the respective output power and efficiency of R-TEG and C-TEG are regarded as an optimized value. The performances of the optimized R-TEG and the original TEG are compared, it can be seen that their output power and efficiency increase with the increase of hot side temperature. The maximum output power and efficiency of the optimized R-TEG can reach to 91.88 W and 4.5% respectively. [ABSTRACT FROM AUTHOR]

• An experimental system is set up for studying the Peltier effect. • The optimal cooling water flow rate is identified. • The impact of Peltier effect on the output performance of TEG is investigated. • Peltier effect makes the maximum power point deviate from the theoretical point. Thermoelectric generator technology can convert heat into electricity based on Seebeck effect, but the Peltier effect cannot be neglected in the thermoelectric conversion process. In order to explore the influence of Peltier effect on the output performance of thermoelectric generator under the fixed heat transfer boundary conditions, an experimental system is set up. In the experiment, the hot side of the thermoelectric generator is heated by a thermostatic heater which can keep the heating temperature constant, and the cold side is cooled through the convective heat transfer with water. The effect of cooling water flow rate on the open-circuit voltage is first analyzed and the optimum cooling water flow rate is confirmed. Furthermore, the influence of Peltier effect on the cold side temperature and output performance of thermoelectric generator is investigated. The result shows that Peltier effect results in the less actual output power than the theoretical value and makes the maximum power point deviate from the point where the load resistance equals the internal resistance. Besides, as hot side temperature advances from 67 °C to 185 °C, the ratio of load resistance to internal resistance increases from 1.2 to 1.307 in the case of maximum output power. [ABSTRACT FROM AUTHOR]