ZEMCH 2019 International Conference Proceedings April.2020 | Page 375
1. Introduction
The PVT collector is a device that uses the heat generated at the back of the PV at the same time as
the electricity produced at the front of the PV. PVT collectors are classified into air and liquid types
according to the fluid used as the heat transfer medium. Air‐type collectors have the advantage of being
easy to manage. Previous studies focused on improving the collectorʹs own thermal and electrical
efficiency through the design, simulation, modeling and experimentation of air‐type PVT collectors.
A review paper of previous studies reviewed the results of air flow and single / double flow paths
of various air‐type PVT systems and various absorber configurations (i.e. fin, V‐groove, round tube,
etc.). As a result, the electrical efficiency was 10‐25%, and the thermal efficiency was 40‐70%. Exergy
efficiency was also in the range of 5‐25% [1, 2].
Based on CFD program (i.e. ANSYS Fluent), Chaube et al. analyzed shape viz. rectangular, square,
chamfered, triangular and semicircle baffles after simulation in the Reynolds number range of 2,900‐
19,500 [3]. Abuska et al. examined the energy, exergy, economics and environmental performance of
air‐type collectors with V‐groove‐shaped protrusions. The thermal and exergy efficiencies were 43‐60%
and 6‐12%, respectively, and the payback period averaged 4.3‐4.6 years. Experiments showed that the
collectorʹs thermal efficiency was about 6% higher than that of the flat collector [4]. Also, Fudholi et al.
studied the exergy and sustainability index of air‐type PVT collectors with V‐groove shaped
protrusions. The exergy efficiency was 13.36% in theory and 12.89% in the experimental results. The
sustainability indexes were 1.168 and 1.148 [5]. Yadav et al. investigated the heat transfer inside the
collector by installing a triangle baffle on the absorber plate using CFD (ANSYS Fluent). Nusselt
number increased with increasing Reynolds number, which was 1.4‐2.7 times higher than without
baffle collector [6]. Choi et al. performed CFD analysis under the same conditions by installing several
resistors inside an air‐type PVT collector. In terms of heat transfer performance, the intersection of
triangular baffles improved by up to 1.86 times [7].
In the case of triangular baffles applied inside the air‐type PVT collector, thermal performance
may vary depending on the installation conditions such as arrangement of the baffles, and dead space
and pressure drop may occur. Therefore, it is necessary to design towards smooth flow inside the air‐
type PVT collector and to increase heat transfer performance.
The purpose of this study was to analyze the heat transfer, pressure drop and thermal efficiency
according to the installation conditions of triangular baffles in air‐type PVT collectors through a
simulation program (i.e. NX CFD).
2. Air‐type PVT collector model for simulation
2.1 Model Design
The air‐type PVT collector designed in this study is shown in Figure 1. The front of the collector is
covered with a general PV module and the size measures 1,011mm x 1,052mm. The air gap of collector
is 40mm. The PV module has a cell covering the front surface like a conventional module, and consists
of about 60 mono crystal cells between two glasses (G / G module). Inside the collector is an absorber
that acts as a heat sink and baffle, with triangular airflow obstructions at regular intervals and
placement. Therefore, the baffle, which is an obstacle, generates turbulence in the flow and is used as
an element to increase the heat transfer performance.
The input values of the lateral spacing (W1) of the baffle and the longitudinal spacing (H1, H2) of
the baffle, affecting the thermal performance of the baffle are shown in Table 1. To adjust the placement
of the baffles in the collector, three parameters were given: W1 (62, 82.5, 144 mm), H1 (0, 47 mm), and
H2 (83, 130, 176.3 mm). In addition, a total of 10 cases were simulated and compared, including a
reference to a PVT collector with a baffle‐free air layer.
Comparative Analysis for Improvement Thermal Performance of
Air-type PVT Collector with Triangular Baffles
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