Design and Experimental Analysis of an Exhaust Air Energy Recovery Wind Turbine Generator

Abstract

A vertical axis wind turbine (VAWT) was positioned at the discharge outlet of a cooling tower electricity generator. To avoid a negative impact on the performance of the cooling tower and to optimize the turbine performance, the determination of the VAWT position in the discharge wind stream was conducted by experiment. The preferable VAWT position is where the higher wind velocity matches the positive torque area of the turbine rotation. With the proper matching among the VAWT configurations (blade number, airfoil type, operating tip-speed-ratio, etc.) and exhaust air profile, the turbine system was not only able to recover the wasted kinetic energy, it also reduced the fan motor power consumption by 4.5% and increased the cooling tower intake air flow-rate by 11%. The VAWT had a free running rotational speed of 479 rpm, power coefficient of 10.6%, and tip-speed-ratio of 1.88. The double multiple stream tube theory was used to explain the VAWT behavior in the non-uniform wind stream. For the actual size of a cooling tower with a 2.4 m outlet diameter and powered by a 7.5 kW fan motor, it was estimated that a system with two VAWTs (side-by-side) can generate 1 kW of power which is equivalent to 13% of energy recovery. OPEN ACCESSEnergies 2015, 8 6567

A Comparative Computational Fluid Dynamics Study on an Innovative Exhaust Air Energy Recovery Wind Turbine Generator

“…The simulation result of this study was verified using the experimental data obtain by Fazlizan et al [24]. The specification of the experimental setup and the computational domain are described in Section 4.1.…”

“…In order to validate the simulation results, they were compared with the experimental data obtained in the laboratory by Fazlizan et al [24]. Figure 2 shows the experimental apparatus used in this study.…”

“…The optimum position of the VAWT rotor was also experimentally tested by Fazlizan et al [24]. It was shown that the best vertical and horizontal distances from the exhaust fan central axis are at 300 mm and 250 mm respectively.…”

“…The researchers in the Mechanical Department of the University of Malaya carried out several experiments, and an analytical study [4,6,[22][23][24]31,32] on VAWT performance. The simulation result of this study was verified using the experimental data obtain by Fazlizan et al [24].…”

“…A mesh independent solution is also required to ensure the quality of analysis. In the second phase, the numerical results were validated by comparing power coefficients with experimental data [24]. Following this step, two diffuser plates were introduced to the design which presented a considerable augmentation in the VAWT performance.…”