ZEMCH 2019 International Conference Proceedings April.2020 | Page 383
1. Introduction
The increasing demand of energy for day‐to‐day activities causes excessive use of fossil fuels,
which ultimately results in an emission of greenhouse gases [1]. This is where the international
organizations for climate control intervene to compel power generation companies to use sustainable
energy instead. Due to this reason, generation of electricity and heat from renewable energy sources
has dramatically increased in last decade [2]. It is anticipated that the use of renewable energy for
residential, domestic, and commercial sectors will increase in near future. Photovoltaic (PV) module is
a device which is used to convert sun rays into electricity, whereas both electricity and heat can be
harvested using Photovoltaic/thermal (PV/T) system [3, 4].
A significant portion of incident solar radiation is ultraviolet and infrared in nature which means
both lead to increase in operating temperature of PV solar cells [5]. Therefore, in context of lowering
PV module temperature and consequently increasing thermal efficiency, an optimized heat exchanger
design and working fluid with superior thermal properties are very important. Water and air are the
most common conventional fluids that have been used as coolants for PV module over a long period
[6]. It has been observed that the PV/T system using water as a working fluid showed higher power
conversion efficiency than that of using air. Liquid fluids have always been the best choice to cool PV
cells than air because of their superior thermo‐physical properties. Furthermore, the PV/T systems can
also be described based on glass covering on PV cells such as the PV module with‐ and without‐glass
covering are called glazed‐ and unglazed‐PV module, respectively [7, 8]. The unglazed PV/T systems
are inexpensive and considered best under high ambient temperature condition because the quantity
of trapped heat on PV surface is lower than using with glazing.
Further, when the quality of energy is main concern then the exergy analysis becomes as important
as the energy analysis [9, 10]. Especially for a co‐generation system which is producing both electrical
and thermal energy simultaneously. Literature review revealed that several studies on the exergy
analysis of various solar energy systems have been carried out with the intentions of developing new
methods and equations [11]. Over the last decade, application of two fluids for extracting heat from the
PV module has been gaining popularity among researchers. Tripanagnostopoulous [12] was the first
who introduced the concept of utilizing two working fluids for a same PV/T collector. Using this
concept, several studies on dual‐fluid PV/T system regarding performance optimization using different
fluids and conduit designs have been published [13, 14]. Jarimi et al. [15] developed a 2‐D steady state
model of a bi‐fluid PV/T system considering a slight modification in finned air channel. The simulation
based results were validated using indoor experimental data.
Based on literature review, it has been observed that several studies have been performed on the
PV/T system considering different aspects e.g. single and dual fluid channels for air circulation. In
addition, lots of reported articles had discussed liquid fluid carrying pipe shapes such as circular,
rectangular and trapezoidal etc. To the best of our knowledge; very limited work has been carried out
on utilization of dual‐fluid heat exchanger for PV/T system. Furthermore, no study has been reported
on dual‐fluid semitransparent PV/T system, in which glass protection above and below the solar cells
has been provided instead of tedlar. Besides, a transient mathematical model of proposed has been
developed using Matlab software and validated using experimental data. It is concluded that due to
provision of dual‐fluid coolant and glass to glass PV protection additional solar heat from the PV
module is extracted, which will result in lower PV cells temperature than that of glass to tedlar PV/T
system.
2. Research Methods
2.1. Mathematical Model
The transient thermo‐electric models for the glass to tedlar and glass to glass PV/T systems were
developed considering energy balance equations across their components. These energy balance
Performance Evaluation of Photovoltaic/Thermal (PV/T) System Using
Different Design Configurations
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