A Photovoltaic Thermal (PVT) Collector is a device that produces electricity and simultaneously uses a heat source transmitted to back side of the Photovoltaic (PV). The PVT collector is categorized into liquid-type and air-type according to the heating medium. As an advantage, air-type PVT system is easy to manage and can be directly used for heating purposes. The performance of air-type PVT collector is determined by various factors, such as the height of air gap and air flow path (by baffles) in the collector. Baffles are installed in the PVT collector to improve the thermal performance of the collector by generating turbulence. However, the air flow that affects the performance of the PVT collector can vary depending on the number and placement of the baffles. Thus, the flow design using baffles in the collector is important. In this study, the performance of an air-type PVT collector due to the arrangement of triangular baffles and air gap height at the back of the PV module is analyzed through a simulation program. For this purpose, Computational Fluid Dynamics (CFD) analysis was performed with an NX program to compare and analyze the optimum conditions to improve the performance of the collector.
BIPV (Building Integrated Photovoltaic) system is a building envelope technology that generates energy by converting solar energy into electricity. However, after producing electrical energy, the remaining solar energy is transferred as heat, raising the temperature at the rear of the BIPV module, and reducing electrical efficiency. On the other hand, a PVT (Photovoltaic Thermal) collector is a device that generates electricity from a PV module and at the same time uses the heat transferred to the air layer inside the collector. In general, the performance of air-type PVT collectors is based on energy analysis using the first law of thermodynamics. Since this performance does not take into account the loss amount, it is not the actual amount of power generation and preheat of the collector that can be used. Therefore, an exergy analysis based on the second law of thermodynamics considering the amount of energy loss must be performed. In this paper, an air-type PVT collector to which perforated baffles were applied was tested through outdoor experiments based on ISO 9806 standard. The total energy (thermal and electrical characteristics) and exergy according to the flow rate (100, 150, and 200 m3/h), solar radiation, and rear temperature of the PV module of the air-type PVT collector were analyzed. As a result, the total exergy efficiency of the air-type PVT collector with perforated baffles was 24.8–30.5% when the total energy efficiency was 44.1–63.3%.
The performance of air-type PVT and BIPVT collectors has been extensively studied. As a system that generates heat and power, PVT collector testing has some particularities especially when using air as a heat recovery fluid and a building-integrated design (BIPVT). The electrical and thermal experimental performance of such collectors are currently being evaluated using in-house methods or PV and/or solar thermal collector standards. The use of a wide range of methods, testing conditions and experimental setups makes it difficult not only to compare the performance of different designs, but also to have confidence in the results obtained. This study evaluates the performance of an air-type BIPVT collector with in-channel perforated baffle plates for heat transfer enhancement designed for a building-integrated façade. As part of a joint research project between Korea and Canada, the proposed collector’s performance was evaluated through indoor (Canada) and outdoor experiments (Korea). Limited comparison of the results obtained with the two testing methods could be performed due to differences in environmental testing conditions, BIPVT collector area and experimental setup. Nevertheless, the limited measurement points under comparable testing conditions indicate that the results from the indoor and outdoor experiments have a similar trend. A comparison between the studied collector having a full PV absorber and a BIPVT collector with a hybrid PV/solar thermal collector absorber using a similar indoor experimental setup and testing conditions was performed. It showed that under still air conditions, for an irradiance level of approximately 820 W/m2 and with a low flow rate, the BIPVT collector with a hybrid PV/solar thermal absorber has a thermal and electrical efficiency of 25.1% and 5.9%, respectively. Under similar conditions, the BIPVT collector with a full PV absorber has a thermal efficiency of 23.9% and an electrical efficiency of 13.5%. At higher flowrates, both units have similar thermal efficiencies, however, the BIPVT collector with a PV absorber remains with an electrical efficiency that is more than double that of the unit with a hybrid PV/solar thermal absorber.
A photovoltaic thermal (PVT) collector uses solar energy efficiently to produce heat and electricity simultaneously. In particular, an air-type PVT collector has advantages over a water type collector because the latter is prone to fluid leakage and condensation problems. However, the performance of an air-type PVT collector is affected by design criteria such as the inner structure (baffle or fins) and fluid path. For this research, PV cell lines arranged alternately with empty lines and curved absorbers were installed in the collecting space of a PVT collector. The absorber was utilized as a baffle to improve its thermal performance. In this study, an outdoor experiment of the PVT collector was conducted. Furthermore, the experimental and simulation results were compared. In addition, the annual thermal and electrical performance of the PVT were evaluated based on TRNSYS modeling.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.