Investigation on thermal-hydraulic performance of the absorber plate using a piezoelectric fan in the solar air heater

This paper presents experimental and numerical research about piezoelectric fan array in solar air heater (SAH) at the frequencies 45-60 Hz by using lamp array as solar radiation simulator. The effective heat transfer coefficient (HTC) of the traditional method such as strip rib on the solar collector and the HTC enhanced by the piezoelectric fan are compared in detail with the different flow rate of the air. A prototype solar collector with a dimension of 300 mm (L)×150 mm (W) is fixed in a wind tunnel in the experiment. Three configurations of piezoelectric fan array which include through-pass and double pass mode have been tested. The results show that the piezoelectric fan can increase HTC or Nusselt number effectively. The Nusselet number is increased by 50∼100%, whereas the pressure drop is increased by no more than 5%. The additional power consumption of the piezoelectric fan is only as low as 0.96 W for 2×2 piezoelectric fan array. The maximum amplitude and the HTC or Nusselt number will be achieved at the resonance frequency, and the vertical setup is the most effective for heat transfer enhancement.