Heat Transfer and Thermal Efficiency of Solar Air Heater Having Artificial Roughness: A Review

Abstract

Abstract-Artificial roughness applied on the absorber plate is the most efficient method to improve thermal performance of solar air heaters .Experimental investigations appropriate to distinct roughness geometries shows that the enhancement in heat transfer is accompanied by considerable rise in pumping power. In view of the fact, a designer needs to carefully examine shape and orientation of roughness elements in order to choose the best fit roughness geometry for intended application. In this paper some distinguished roughness geometry has been compared on the basis of heat transfer enhancement and thermo hydraulic performance. The objective of this paper is to review various studies, in which different artificial roughness elements are used to enhance the heat transfer rate with little penalty of friction. Correlations developed by various researchers with the help of experimental results for heat transfer and friction factor for solar air heater ducts by taking different roughened surfaces geometries are given in tabular form. These correlations are used to predict the thermo hydraulic performance of solar air heaters having roughened ducts.

The effect of closed cycle of air flow circulation on the thermal performance of solar air collector

“…The establishment of the energy balance takes into accounts the solar energy absorbed by the absorber plate and the useful thermal energy of the system accompanied by certain energy losses [14]. The thermal equilibrium of the transparent cover is:…”

“…The increase in thermal efficiency is achieved through the increase of the exchange or transfer surface area using baffles [11][12][13][14] which subsequently creates turbulence [15][16]. The transfer can take different ways such as using the tube heat exchanger, cross-corrugated and multi-pass flat-plate solar air heaters with external recycle [17][18][19][20].…”

Buoyancy Induced Air-Flow through a Pin Hole

“…The thermal efficiency of the SAH which are made rough through artificial means was deliberated [10]. The thermal transfer and the thermal performance of SAH possessing rough nature through artificial means were studied [11]. CFD (Computational Fluid Dynamics) approach was used to calculate the thermal transmission and the examination of the fluid's movement in SAH [12] CFD is the study which involves fluid transmission's thermal motion that makes use of the computer based simulation.…”

Performance Analysis of Three Side Roughened Solar Air Heater: A Preliminary Investigation

“…The impact of artificial roughness on the performance of SAHs has been studied in [ 5 ] to provide comprehensive information about the different cross-sectional roughness elements, and the effect of these roughness elements on the performance of SAHs has been discussed. The different directions and arrangements have been studied by Saurav and Sahu [ 6 ] for artificial roughness in SAHs. Furthermore, the utilization of various artificial roughness geometries has been reported in SAHs to enhance the heat transfer rate and thermal effectiveness [ 7 ].…”