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

The global climate crisis has led society toward cleaner energy sources. Another reason is the limited reserves of fossil energy resources. Efforts to increase the efficiency of photovoltaic modules (PVs) have gained momentum. The high temperature is the biggest factor causing a decrease in the efficiency of PVs. In this study, a commercial PV was cooled with distilled water, a multiwalled carbon nanotubes (MWCNT)/water mixture, and a graphene nanoplatelets (GNP)/water mixture. The environmental impact of electricity, total energetic efficiency, energy payback time, energy return on investment, and embodied energy of the PV/thermal (PV/T) system were compared using life cycle assessment and cumulative energy demand. The electrical efficiency of the PV/T changed between 13.5% and 14.4%. The total efficiency of PV/T changed between 39.5% and 45.7%. The energy returns on investment were 1.76, 1.80, and 1.85 for PV/T-distilled water, the PV/T-MWCNT/water mixture, and the PV/T-GNP/water mixture, respectively. Moreover, the embodied energy evaluation values were 3975.88 MJ for PV/T-distilled water, 4081.06 MJ for the PV/T-MWCNT/water mixture, and 4077.86 MJ for the PV/T-GNP/water mixture. The main objective of this research was to study the energy and environmental performances of PVs cooled with different nanofluids and draw general conclusions about the applicability of these systems.

The integrated usage of solar energy systems, heat pump applications, and thermal energy storage units is an effective way for heating systems due to their sustainability and stability in operations. In this study, a novel direct solar-assisted heat pump with thermal energy system has been designed which uses the solar collector as the evaporator of the heat pump. Besides, two-dimensional transient numeric analyses have been conducted for the thermal energy storage unit using the ANSYS Fluent 16.2 commercial software package. With this direct system, the heat required for heating systems is supplied from the condenser with the heat received from the solar collector of the working fluid. For an effective and high performance system, the solar collector is designed as a double-pass which provided superheating of the working fluid. It is aimed to store the surplus energy from the solar energy in the thermal energy storage unit and to operate the system continuously and efficiently in both sunny and overcast weather conditions. Furthermore, the system has been analyzed theoretically and the results show that coefficient of performance may improve. As a result, this newly designed system can be successfully applied for thermal applications.