This work presents performance analysis of a novel multi-pass solar air collector with perforated fins (MPSACF) in winter conditions, Ankara province, Turkey. The aim of this work is to experimentally test and compare the performance of the two different design of solar collectors in the same climatic conditions. In addition, a double-pass solar air collector without fins (DPSAC) at the same absorber area was manufactured and tested as a control group. The total absorber area of both solar collectors is 0.325 m2. Thermal effects for performance improvement of the collectors have been designated. Average thermal efficiency values of DPSAC and MPSACF were calculated as 47.85% and 51.86%, 67.10% and 72.86%, respectively in experiments performed at 0.0069 kg/s (0.7 m/s air velocity) and 0.0087 kg/s (0.9 m/s air velocity) mass flow rates. Exergy efficiency of DPSAC and MPSACF were 2.10-17.12% and 8.74-23.97%, respectively. Coefficient of performance(COP) values were ocomputed 4.63 and 4.94, 3.18 and 3.48 respectively in experiments performed at 0.0069 kg/s and 0.0087 kg/s mass flow rates. Although the MPSACF has high efficiency values, COP values are lower due to the presence of dual fans. Because of their high thermal efficiency, both collectors can be effectively practiced for applications such as preheating, space heating and ventilation, greenhouse heating and product drying©2019. CBIORE-IJRED. All rights reservedArticle History: Received May 16th 2018; Received in revised form October 16th 2018 ; Accepted January 6th 2019; Available onlineHow to Cite This Article: Aktaş, M., Sözen, A., Tuncer, A.D., Arslan, E., Koşan, M., Çürük, O. (2019) Energy-exergy analysis of a novel multi-pass solar air collector with perforated fins. International Journal of Renewable Energy Development, 8(1), 47-55.http://dx.doi.org/10.14710/ijred.8.1.47-55

On the analysis of solar radiation and meteorological variables measured in Ankara province in Türkiye from 2017 to 2018, an empirical model of global solar radiation was developed. The global solar radiation at the ground and at the top of the atmosphere (TOA) was calculated and in good agreement with the observations. This model was applied to compute the losses of global solar radiation in the atmosphere and the contributions by atmospheric absorbing and scattering substances. The loss of global solar radiation in the atmosphere was dominated by the absorbing substances. The sensitivity test showed that global solar radiation was more sensitive to changes in scattering (described by a scattering factor S/G, S and G are diffuse and global solar radiation, respectively) than to changes in absorption. This empirical model was applied to calculate the albedos at the TOA and the surface. In 2017, 2018, and 2019, the computed albedos were 28.8%, 27.8%, and 28.2% at the TOA and 21.6%, 22.1%, and 21.9% at the surface, which were in reasonable agreement with satellite retrievals. The empirical model is a useful tool for studying global solar radiation and the multiple interactions between solar energy and atmospheric substances. The comparisons of global solar radiation and its loss in the atmosphere, as well as meteorological parameters, were made at some representative sites on the Earth. Some internal relationships (between G and the absorbing and scattering substances, air temperature and atmospheric substances, air temperature increase and latitude, etc.) were found. Thus, it is suggested to thoroughly study solar radiation, atmospheric substances, and climate change as a whole system and reduce the direct emissions of all atmospheric substances and, subsequently, secondary products (e.g., CO₂ and non-CO₂) in the atmosphere for the achievement of slowing down climate warming.