The present study experimentally compared the flat plate-based PVT system with and without double-crimped galvanized iron wire mesh. The comparison was made based on energy and exergy-based parameters. Further, life cycle assessment was conducted to test the enviroeconomic suitability of the modified unit as compared to the conventional unit. The experimental investigation was conducted at a constant airflow rate of 0.0165 kg/s under outdoor conditions in Noida, India. The results revealed that the PVT-M unit (with wire mesh) maintained 2.9°C lower PV module temperature and 2.2 °C higher outlet air temperature than the PVT-F unit (without wire mesh). On an annual basis, the PVT-M unit achieved 41.2 %, 78.55 %, and 1.34 % higher thermal energy, thermal exergy, and net electrical energy generation, respectively, compared to the PVT-F unit. Despite consuming 2.5 % higher invested energy, the PVT-M unit needed 13.7 % (overall energy basis) and 2.5 % (overall exergy basis) less time to recover the invested energy. The modified unit also presented superior environmental performance by mitigating 18.6 % (overall energy basis) and 5.2 % (overall exergy basis) of annual CO₂ emissions, respectively. Therefore, with better values of life cycle parameters, the PVT-M unit has enhanced techno-economic and environmental viability over the conventional PVT unit.

The present study explored the benefits of using the trapezoidal plate as a heat exchanger over the plain plate in a PVT unit (conventional unit). The study compares the performance based on annual energy and exergy generation, key energy matrices, CO2 mitigation, and corresponding carbon credits. Initially, the airflow rate was optimized from the range of values 0.0039-0.0117 kg/s, identifying 0.0094 kg/s as optimal for the annual performance assessment. Experiments were carried out on the rooftop of the Department of Mechanical Engineering, NIT Silchar, India, from December 2022 to November 2023. Results indicate that the trapezoidal plate-based unit maintains a 2.8 degrees C lower PV module temperature and a 1.9 degrees C higher outlet temperature compared to the conventional unit. The exergy destruction rate of the trapezoidal plate unit is 1.89 % and 2.73 % lower than the conventional unit on a typical winter and summer day. Additionally, it generated 8.7 %, 8.4 %, and 1.62 % higher annual overall energy, overall exergy, and net electrical energy than the conventional unit. The energy payback time achieved by the trapezoidal plate unit is 9.5 % (overall energy) and 5.4 % (overall exergy) less than the conventional unit. Additionally, the trapezoidal plate unit mitigates 8.6 % and 8.8 % more CO2 mitigation annually on an overall energy and exergy basis, respectively.

In the present study, it is experimentally investigated how the functionality of a photovoltaic thermal unit is affected by utilizing a rotating turbulator and a hybrid nanofluid at the same time. Twisted tape is used as turbulator and water-TiO2/Co3O4 is considered as nanofluid. Two perspectives of energy and exergy are used to analyze the functionality of the unit. The impacts of mixing ratio of TiO2:Co3O4 nanoparticles (1:0, 0.9:0.1, 0.7:0.3, 0.5:0.5, 0.3:0.7, 0.1:0.9, and 0:1), volume concentration of nanofluid (0 %, 0.1 %, 0.5 %, and 1 %), mass flow rate of nanofluid (20, 40, 60, and 80 kg/h), twist pitch of turbulator (10, 30, and 66 mm), and turbulator rotating speed (0, 100, 200, 300, 400, and 500 rpm) on the system functionality are examined. The highest overall energy efficiency of 73.28 % was achieved at a nanofluid concentration of 1 %, twist pitch of 10 mm, rotational speed of 500 rpm, and mass flow rate of 80 kg/h. Moreover, the highest overall exergy efficiency of 13.83 % was achieved at a nanofluid concentration of 1 %, twist pitch of 10 mm, rotational speed of 400 rpm, and mass flow rate of 20 kg/h.

Photovoltaic (PV) technology can be categorized as a mature technology but its performance with its elevating temperature has a negative effect and opens a new area of research which led to the introduction of photovoltaic thermal collector (PVTC) systems. PVTC systems integrate PV modules and solar thermal collectors in a single unit to derive energies from uninterruptible solar sources. This review article is limited to the design and development of the heat exchangers used in typical air and water-based PVTC system. Heat exchangers are used to improve the heat transfer from the back surface of the PV module, thereby improving its overall efficiency. The review shows that for air-based PVTC, the electrical efficiency with various types of heat exchangers lies in the range of 4-24%, whereas for water-based PVTC is 5.1-15.8%. The maximum thermal efficiency achieved for the water-based system is observed to be 72% against the 87% for the air-based system indicating that a significant approach has been made in the air-based system with the novel concept of the heat exchangers as compared to the water-based system. At the end of the paper, some future recommendations are also commented on to make the PVTC system more viable.

Helical geometry is widely used in heat transfer systems due to the high heat transfer surface and the creation of swirling flow. Grooving the spiral channel can lead to the strengthening of these effects and improve the channel performance. In the present study, the energy and exergy performance of a nanofluid-based photovoltaic thermal unit equipped with a grooved helical microchannel heat sink is investigated experimentally. For this purpose, a plain helical microchannel heat sink, a parallel grooved helical microchannel heat sink and a staggered grooved helical microchannel heat sink are designed and fabricated. The employed nanofluid is the aqueous suspension of Fe3O4 nanoadditives. The experiments were performed at different values of flow rates (20-80 kg/h) and nanoadditive concentrations (0.0-2.0 %). The highest thermal energy/exergy, electrical energy, and their corresponding efficiencies have been recorded at the mass flow rate of 80 kg/h and nanoadditive concentration of 2.0 %. It is seen that the overall energy efficiency of the staggered unit is 17.05 % and it is 6.96 % higher than the plain and parallel unit. Further, the staggered unit demonstrated the highest exergy efficiency (14.67 %) compared to other studied photovoltaic/thermal units.

Partially covered photovoltaic thermal collector (PVT-C) unit has the capability of generating high thermal energy/exergy and a meaningful electrical energy. This study is aimed to modify the traditional unit of PVT-C to improve energy, exergy, and electrical energy generation capability by replacing a flat absorber plate with a wavy absorber plate. A wavy absorber plate is integrated with the partially covered PVT-C unit (PVT-WPC unit) and compared with the partially covered PVT-C unit having a flat absorber plate (PVT-FPC unit). These two units are compared with the yearly values of overall energy and exergy generation capability at an airflow rate of 0.03 kg/s. This work aims to reveal the viability of the modified unit in terms of energy matrices. The findings reveal that the partially covered PVT-WPC units generate 1%, 10.9%, and 14.9% higher yearly net electrical energy, overall energy, and overall exergy than the partially covered PVT-FPC unit. In terms of yearly overall energy and overall exergy, the partially covered PVT-WPC units have achieved 8.7% and 12.5% lower energy payback time (EPBT) and 10.9% and 14.9% higher CO2 mitigation as compared to the partially covered PVT-FPC unit.

The intent of the present investigation is to conduct; experimentally, the effects of nanofluid of water/magnetite and flow channel arrangement on photovoltaic thermal (PVT) systems. Three different configurations of the collector in PVT were researched in various nanofluid’s flow rate of M˙=20.0−80.0(kg/hr), and nano concentration of φ=0.0−2.0%. The studied arrangements of flow channels in the collector are a sheet-and-plain serpentine tube (PVT-0S), a sheet-and-finned serpentine tube with four fins (PVT-4S) and a sheet-and-finned serpentine tube with eight fins (PVT-8S). The electrical efficiency is compared between the cited three cases and the PV panel without cooling system. The maximum energetic, exergetic and electrical performances were found at the flow rate of M˙=80(kg/hr) and nano concentration of φ=2.0%. It was observed that the PVT-8S system provides the most efficient configuration since the overall energy efficiency (η) in the PVT-8S system are 5.87%, and 15.59% higher than the PVT-4S, and PVT-0S systems. Further, the PVT-8S system demonstrated the maximum value of exergy efficiency (Γ=14.51%) compared to other studied systems. It was also shown that the electrical efficiency (Λ) augments significantly with the adding the cooling systems to the PV panel. The increase in the electrical efficiency was 12.06%, 10.87%, and 8.40% for the PVT-8S, PVT-4S, and PVT-0S systems; respectively.

This experimental study aims to energetically and exergetically compare the performance of a PVT system with sheet-and-plain serpentine tube collector (base PVT system) with two cases of modified PVT systems. The modified PVT systems are the replacements of plain serpentine tube with rifled serpentine tube with 3 ribs (3-start rifled PVT system) and 6 ribs (6-start rifled PVT system). The electrical parameter of the PV module without cooling is compared with the three cases of the PVT system with cooling. The cooling fluid is water/magnetite nanofluid. The effect of nanofluid flow rates (20-80 kg/h) and nano additive volume concentrations (0-2%) over the three cases of the PVT system is investigated to propose a suitable combination of flow rate and NA concentration offering the best energetic and exergetic performances. Thus, the 6-start rifled PVT system achieved a maximum of 22.5% and 3.8% higher overall energy efficiency, and 5.9%, and 1.9% higher overall exergy efficiency than the base and 3-start rifled PVT systems at flow rate and concentration of 80 kg/h and 2%. Finally, the electrical power generated by the base, 3-start rifled, and 6-start rifled PVT systems achieved maximum enhancement of 27.5%, 29.5%, and 31.5% compared to the PV module without cooling. ? 2021 Elsevier Ltd. All rights reserved.

In this experimental investigation, an effort is executed to evaluate and compare the energetic and exergetic performances of three nanofluid-based photovoltaic/thermal (PVT) systems, namely a PVT system with a sheetand-serpentine tube collector (case-I), a PVT system with a sheet-and-grooved serpentine tube type collector with a groove pitch of 8 mm (case-II), and a PVT system with a sheet-and-grooved serpentine tube type collector with a groove pitch of 5.4 mm (case-III). The water-Fe3O4 nanofluid was considered as the working fluid. The influences of nanoadditive concentration (sic) (0-1%) and flow rate (m(f)) of nanofluid (10-40 kg/h) on the performance features were then examined. It was found that at any given (sic), the overall energy, overall exergy, and electrical performances of the case-I, II, and II improved with an increase in nanofluid m(f) (10-40 kg/h) and vice versa. Thus, the case-III yielded 15% and 6% better overall energy efficiency, 4.6% and 2.3% better overall exergy efficiency, and 3.3% and 1.9% better electrical energy efficiency than the case-I and II at a (sic) and nanofluid m(f) of 1.0% and 40 kg/h. The maximum electrical energy of case-I, II, and III is 9.5%, 11%, and 13.1% higher than those achieved by the PV panel in absence of cooling. The findings obtained from this study can be used to design photovoltaic systems with significant energetic and exergetic performance.

The objective of the present study is to explore the performance of air-based photovoltaic thermal (PV/T) collector to generate both thermal and electrical energy. Outdoor tests are performed by varying the PV coverage areas (25-100%) and by using two different types of absorber (wavy and plain) under the climatic condition of North-East India. Mass flow rate of air is varied between 0.01 and 0.04 kg s(-1). Results indicate that high overall energy performance has been achieved at a 25% PV coverage area while the high net electrical energy and overall exergy have been observed at a 100% PV coverage area for both the PV/T collectors. Further, wavy absorber plate based PV/T collector provides upto 2.7% lower PV panel temperature and 4.5% higher outlet air temperature as compared to traditional PV/T collector. Moreover, a partially covered PV/T collector with a wavy absorber plate has achieved marginally higher net electrical energy and 3.5% overall exergy efficiency than that of the plain absorber plate. However, a partially covered PV/T collector with a wavy plate has achieved an 11.2% higher overall thermal efficiency than the partially covered PV/T collector with a plain plate.

In this paper, the performances of two different configurations of the PVT air collector (PVTAC) were studied and compared with respect to three energy matrices: energy payback time, electricity production factor, and life-cycle conversion efficiency. Geometrically, both configurations are similar except one equipped with a flat plate collector (PVTACF) and other with a wavy plate collector (PVTACW). An experimental investigation was performed for both the models, located at Silchar (Latitude: 24.8333 degrees N and Longitude: 92.7789 degrees E) over a period of 1 year (May 2017 to April 2018). Initially, airflow velocity was varied between 1-3 m/s and ideal airflow velocity (2.5 m/s) was identified. The yearly energetic and exergetic performance was studied and presented. The overall annual energy and exergy of the PVTACW were achieved by 8.2% and 2.3% higher than the PVTACF. The energy payback time, electricity production factor, and life-cycle conversion efficiency of the PVTACW were also achieved better than the PVTACF. The study provides useful information on the energetic performance and environmental impact of the PVTAC system under North-East Indian climatic conditions.

In this work, a comparative experimental energy and exergy analysis of photovoltaic thermal air collector (PVTAC) with a flat plate (model-I) and wavy plate (model-II) as a solar thermal collector is performed. Integration wavy plate is expected to enhance the rate of redistribution of fluid flow and thus to enhance the heat extraction rate. Thereby helps to control the temperature of the PV module during higher solar insolation, during which the conversion efficiency of the PV module tends to decrease. The experimental investigation of performance enhancement of PVTAC is carried out at different values of airflow rates of 0.0047-0.0165 kg/s. Results indicate that the highest overall thermal energy and overall thermal exergy of the PVTAC system are obtained during noontime. Comparative analysis indicates, at noon, model-II provides a higher yield of thermal energy, exergy, and net electrical energy by 16%, 27.4%, and 1.2% than that of model-I. Presence of the wavy plate increases the magnitude pressure drop for model-II than that of model-I. Despite meeting the requirement of higher pumping power, model-II provides 8.4% and 1.3% higher overall thermal efficiency and overall exergy efficiency than that of the model-I.

The performance of photovoltaic thermal (PVT) air collector has been studied in the climatic condition of North East, India theoretically and as the climatic condition of north east is different from the other zones of India. For this study, one of the city located in north eastern India named Silchar is chosen. Firstly, the validation of the theoretical model has been done with the experimental model of Agarwal and Tiwari (2012) which shows that theoretical model is in fair agreement with the experimental model as the correlation coefficient and root mean square percent deviation has been found as 0.94 and 9.1 %. The study is performed with three different values of mass flow rate (0.007 kg/s, 0.0097 kg/s and 0.0128 kg/s) for a typical day of December and March. It has been found that the maximum solar radiation has been achieved at 12.00 hr of the day for both the month under consideration. The nature of variation of solar cell temperature, back surface temperature, outlet air temperature, thermal and exergy gain throughout the day has been observed for different mass flow rates. It was reported from the study that the PVT air collector has better thermal performance for the mass flow rate of 0.0128 kg/s. For a mass flow rate of 0.0128 kg/s, it has been observed that for a typical day of December, the thermal energy gain and exergy gain has been achieved as152 Wh, and 7.88Wh, respectively, whereas for the month of March it has been observed as 185.15 Wh, and 17.82 Wh, respectively at 12.00 hr. Maximum outlet temperature has been obtained as 45°C, and 53°C, during winter (December) and summer (March), respectively. The exergy gain is found to enhance by almost 100% during summer than that of winter.

Due to the rapid industrialization and development across the entire globe, there is the increasing demand for energy. However, the energy sources from fossil fuels are not abundant in every part of the world. India has to import fuel from other parts of the world which consumes a major portion of Government funds. So, currently improving solar energy technologies efficiency is one of the most promising researches in India. This study is mostly about life cycle assessment (LCA) of photovoltaic thermal (PVT) air collectors. All the important parameters like Energy payback time (EPBT), Energy production factors (EPF), Lifecycle conversion efficiency (LCCE), Embodied energy, Life cycle cost assessment (LCCA) and carbon emissions are investigated in this study as well. The role of these parameters in the LCA study is depicted in this study since LCA greatly impacts the effectiveness and cost of PVT air collector. Results revealed that the EPBT, GPBT, EPF, and LCCE are in the range of 0.8 to 14 years, 1 to 4 years, 0.4 to 22, and 0.10 to 2.86.

With the rapid depletion of fossils fuels, opportunities for renewable energy including solar energy are endless. The efficiency of photovoltaic cells to convert the solar energy into electricity drops with the rise in temperature due to increased resistance. Thus, improving the efficiency by lowering the thermal resistance and allowing the cooling fluid (air/water) to flow through photovoltaic thermal (PVT) system is an attractive option. Climate condition based performance of any PVT system varies location wise, and cannot be generalized. Silchar is a city located in Himalayan region has tropical climatic conditions and most of its decentralized villages are out of grid connectivity. Unlike other metro cities of India, PVT will play a critical role for the development of theses villages. Keeping this in mind an attempt is made in the present study to perform an analysis of single glazed solar PVT air collector on the basis of energy and exergy for the climatic conditions of Silchar, India. An analytical model is developed to evaluate the hourly variation of PV cell temperature, cell efficiency, useful thermal heat gain, useful electrical heat gain, energy efficiency and exergy efficiency PVT system. Results depict that efficiency of PV cell decreases with the increase in temperature, and a maximum efficiency of 14.6% for the PV module is found. Out of total useful heat output, the thermal heat output contributes 60.7% while the rest is electrical heat output. Further, magnitude of the heat output is found to increase with the solar radiation and the maximum observed solar ray at around 12:30 h. Trend of both energy and exergy efficiency is similar except the magnitude. Maximum efficiency observed to be 83% and 16.5% for energy and exergy, respectively.