Abstract
Photovoltaic modules can generate more electricity
when receives a big quantity of solar radiation, but the
efficiency of (PV) modules will drop when the
temperature of solar cells is high. Therefore, reducing
the high temperatures of (PV) modules will contribute
to increase the electrical efficiency of (PV) modules by
extraction the thermal energy associated with the PV
modules and achieve an appropriate conversion
efficiency of (PV). The aim of the study in this paper is
to recognize the performance of hybrid (PV/T) systems
in different places, conditions, module designs which
can be used in household applications, hotels, etc.
Aiming to supply of electricity and thermal energy. The
study indicates to use of cooling technique (water or
air) to cooling (PV) modules will contribute to a large
extent to strengthen the work of solar cells and the
efficiency of (PV/T) system as well. And the rate return
of the system of electricity and thermal energy will
increase, especially when the hybrid photovoltaic/
thermal (PV/T) solar systems were properly designed
and the conversion rate of absorbed solar radiation for
(PV) modules will increase as well.
Keywords
Photovoltaic, Thermal energy, PV efficiency, Solar
radiation, Combisystem.
Introduction
Hybrid photovoltaic/thermal system experiencing
rapid growth which provides simultaneously both
electrical and thermal energy making it interesting for
many applications [1], For that many researches has
been conducted in developing and improving the
performance of the system by increasing its
efficiency, use (water or air) as a technique to cooling
solar cells the temperature reaches high levels and the
negative effects on the work of the solar cells will
appear [2]. This system contributes to reduction of
environmental problems by reduce CO2 emissions
are needed in houses and buildings and concentrate
on use renewable energy that should be more actively
[3], the amount of energy that produce from hybrid
PV/T system depend on the photovoltaic which
convert only a small part of the absorbed solar
radiation into electricity and type of solar cells use,
where the greater part of solar radiation converted
into heat and that lead to increasing their temperature
and decreasing their electrical efficiency [4], Hybrid
PV/T system produces electricity and heat (air or
water preheating), that will contribute to improve
efficiency of PV(/T) modules by extracting the heat
loose by using (air or water) as a removal fluid and
take this advantage for using in many applications [5].
Several study have been done about using air or water
PV/T systems some of research found that use water
systems seem desirable because of the nature of this
fluid allowing better recovery of the heat [6], while
other researches find that the results from an applied
air type PV/T system gives a variety of results
regarding the effect of design module and operational
parameters on the performance of air type PV/T
systems [7, 8], where can use the air to cool the
surface temperature of the PV panel after pick up the
surface heat which can use for household application,
drying and other industrial purposes [9]. To ensure
solar cell operate at low temperature and keep the PV
module efficiency at a sufficient level, where used
natural or forced (air or water) circulation as a simple
method to remove heat from PV modules, but this
method is less effective, especially if the ambient
temperature is more than 20ºC, to overcome that can
be extracted the heat by circulating (air or water)
through a heat exchanger that is mounted at the back
5
HUNGARIAN AGRICULTURAL ENGINEERING
N° 32/2017 5-15
Published online: http://hae-journals.org/
HU ISSN 0864-7410 (Print) / HU ISSN 2415-9751(Online)
DOI: 10.17676/HAE.2017.32.5
A REVIEW OF PERFORMANCE HYBRID PHOTOVOLTAIC/THERMAL
SYSTEM FOR GENERAL - APPLICATIONS
Author(s):
M.H.R. Alktranee
Affiliation:
Department of Mechanical, Technical Institute of Basrah, Southern Technical University, Basrah, Iraq.
Email address:
mohammed84alktranee@gmail.com
PERIODICAL OF THE COMITTEE OF
AGRICULTURAL AND BIOSYSTEM
ENGINEERING OF
THE HUNGARIAN ACADEMY OF SCIENCES
and
SZENT ISTVÁN UNIVERSITY
Faculty of Mechanical Engineering
Received: 2017.08.12. - Accepted: 2017.11.18.
surface of the PV module. Where PV/T systems
provide a higher energy output than standard PV
modules and could be cost effective additional to that
thermal unit is low [10-12]. These systems which
working as solar active devices need requires to good
oriented surfaces that towards the equator by suitable
orientations on the surface must be exploitation for
each square meter with orientation in order to achieve
maximize the energy yield with keep the efficiency
in suitable level [13]. Therefore, numerous researches
done on the analytical and experimental studies of
PVT systems in different places and conditions,
intended to find out the methods that Contribute to
increase the efficiency of these systems [14].
2. Behavior of hybrid photovoltaic/thermal
system by using water
Modeling and simulation of hybrid PV–thermal
solar system by use TRNSYS
The hybrid photovoltaic/thermal system which can
provide at the same time both electricity, thermal
energy and according to Cyprus conditions, it has
worked both of “Soteris and Kalogirou” by used the
system it has been modeled using TRNSYS. Where
the system consists of collection of series of PV
panels included on a normal PV panel at the back of
the heat exchanger fixed fins, a battery, an inverter,
hot water storage for thermal system, pump through
experiments daily, monthly and performance that
done by the system. The results show that the average
annual efficiency of the PV solar system was between
2.8% to 7.7%, thus increasing the mean annual
efficiency of the system to 31.7%. And the best water
flow rate of the system was 25 l/h. That would cover
49% of the hot water needs of a house [15]. A hybrid
system which could be generating both electricity and
hot water warming, it has been modeled number of
cases in order to improve the water flow rate to
collector. The outcome found that the electricity
produced from the PV panel increases with the flow
rate increases. Also, the outcomes show the primary
value corresponds to 25 l/h, which mean low flow
rate value for the system can be used in a
thermosyphon module without depending to use a
pump and which will improve the economic
feasibility of the system [16].
6
Figure 1. Field experimental results of the hybrid solar collector: (a) operating results of hybrid solar
collector, (b) alternating current power generation, (c) heat fractions for domestic hot water supply [3]
Perform experiments on a hybrid PV/ T solar
collector
Conventional flat plate collector solar thermal with
PV cells composite working in the absorption solar
radiation for the output of both electrical and thermal
energy, has removed the heat from PV cells that led
to higher electrical efficiency of the photovoltaic and
useful thermal energy extracted from one of the ends
the ducts [17], as well as conducted tests and analyzes
on performance the hybrid PV/T system which
generation electricity and thermal both, this
experiment done by constant temperature processing
of marinade made. Where found that the conversion
efficiency ranged from 10% to 13%, and collector
efficiency was from 20 to 40 ºC marinade than 40%
heat and 50% and about 20% of successive [3].
Although there was reduced of collector efficiency, it
has compared the efficiency of the hybrid solar
collectors for this photovoltaic solar collectors, where
were reads in the observational results of this study
annual operation to assemble solar hybrid and the
Figure 1a below show the maximum monthly amount
of current energy 45.3 MJ / m
2
in June, and the
minimum 2.8 MJ / m
2
in January, it means conversion
efficiency groups.
Where stabilized about 25-28% with the exception
in the winter season, it was stable at around 8-9%, only
in the winter and the maximum value was 28.1% in
august. In Figure 1b shows the difference monthly,
current energy of the hybrid system and amorphous
silicon photovoltaic per unit area of the panels 0.7 and
0.4 MJ / m
2
d, respectively, with the value of hybrid
solar collector energy it was about 80%,A Where the
efficiency decreased because snow due to thickness of
snow in Figure 1c below shows the monthly and
annual variation of provider of domestic hot water
energy, where it was 13.1 GJ which was comparable
to that value for the flat plate solar collector 46.3% [3].
Production electric and thermal energy of hybrid
PV/T solar systems
Exploitation the amount of energy from hot water and
electricity led to motivate many researchers to
develop the performance of hybrid PV/T system in
order to maintain the electrical efficiency of
photovoltaic cells at the adequate level at high
temperature, it is necessary for the operation of PV
modules at low temperatures by using natural or
forced air circulation simple and low-cost methods
for transferring heat from the PV modules [18, 19].
The study was conducted at three sites in different
regions of, Nicosia, Athens and Madison. As well as
used in this study the prototype from polycrystalline
silicon (PC-Si) and amorphous silicon (a Si) and used
to analysis the outcome a simulation TRNSYS.
However, during the test found the production of
electric power from the hybrid system is less than
standard PV modules (maximum 38%) units Si PV
gives increased total energy production compared to
Si PV modules, Nevertheless, the contribution of
solar energy to heat water rising in cold climates.
Results showed and PC-Si cells produce more
electricity (PEL) than identical a-Si cells, this due to
higher efficiency of PC-Si cell. The a-Si cells produce
more useful thermal energy at all three sites into
Madison, Nicosia and Athens. The outcomes
indicated that the electricity yield of solar system
employing polycrystalline solar is more than that
employ these amorphous, but the solar thermal
contribution a little less. PV is a hybrid system
produces about 38% of electric power and the
domestic thermosyphonic system effective and
largest system appropriate for residential construction
or low office buildings [20].
Use direct solar floor for hybrid PV/T collectors to
experiment Energy performance
The energy performance of water hybrid PV/T
collectors where worked on this application both of
Sorensen, Monroe, it has applied on combisystems of
direct solar floor type. The target of this study was to
take advantage of the hybrid solar collector to achieve
maximize the contributions of solar energy to
generate electricity and thermal profits useful. This
application operates in the integration of photovoltaic
(PV) modules in buildings allows one to view the
multifunctional and then to trim back costs by
replacing frame ingredients, used with this
application amorphous cells or composed to improve
the thermal output PV /T collector. To consider that
hybrid PV/T solar water collectors as a one piece that
including thermal absorption the heat exchanges and
PV functions, by one day in summer (June) noticed
the PV cell temperature there are evolving in their
efficiency when the cell temperature increases, also
in their efficiency which strongly dropped decreases
from 7% to 4% [21]. As shown in Figure 2. On the
same day the cell efficiency was stable around 8.4%,
which represents a reduction of 28% and the annual
efficiency of the conventional photovoltaic
component was 9.4%. This is obviously due to the
high temperature on the cover and the incident
radiation on the PV cells decreased due to glass cover.
It has found that without a glass cover the efficiency
was 10%, this is 6% more in effect than a standard
module because of the cooling effect [22]. Thus, it
has gone from the traditional combisystem associated
7
control system which purports to extend the solar
thermal energy output. As well as for heating water
in homes by the water glycol flow in the back side of
the PV modules. It has considered that at least one of
the two hybrid solutions (with covered or not) is more
efficient than the traditional one (PV + T), in order to
avoid the reduction of the age of solar hybrid
assembly found two choices. The first one is obvious
to imagine the collector is covered and the second is
to study the PV modules which can be stable at high
temperature [23].
8
Figure 2. The PV cell temperature and efficiency evolutions [22]
Energy generation with a photovoltaic (PV/T)
solar hybrid system
Many combinations of electricity generating solar
systems and heat generating have been studied to
cover the needs in large quantities to a residential
house typical for a family without any fuel cost with
average daily consumption of electric power for
domestic about 7 kWh. Where the hybrid system
consists of (PV) module and compound solar thermal
collector energy are constructed and tested for energy
collect, the study was conducted in Cyprus have
comparatively high averages of exposure solar
radiation throughout the year, hot summer days
somewhat and for long periods and mild winters to
some extent [24]. Depending on the type of solar cells
with occupies an area of about 10 m
2
, found that the
amount of energy can be produced in electric with a
1600W (PV) system. Therefore large area solar
modules will absorb large amounts of solar
irradiation, so that will causes loss at the same time
in heat units, it has examined experimentally some of
hybrid system and found that when using of a booster
diffuse reflector will contributed increased the
performance of the system and gave giving
possibilities for more active for practical applications
take the benefit of absorbed solar energy which is not
converted into electricity to utilized for thermal
applications [25]. A result of this excessive heating
of the modules will led to reduction of conversion
unit’s efficiency, for this reason some of this type does
not convert 80-95% of the energy collected to
electricity to remove the extravagant heat. many
systems have been designed to use it as an energy
source for some other applications like household and
industrial applications. As will found that the
structure of the unit required some adjustment like to
allow to distribute the medium cooling in order to the
heat extraction when it is heat fluid transfer system
either air or water and to enable watertight and
corrosion free construction used water need a more
overall amendments [26], The results obtained from
these study PV modules absorb a significant sum of
solar radiation that generates unwanted heat;
however, this loss represents only 1% of the energy 7
kWh that is consumed by the typical family the
proposed hybrid system produces thermal energy
roughly 2.8 kWh per day. That led to total loss about
11.5% in electric power generation, because the
different parts that are placed over the hybrid
modules. The payback adjustment period was less
than 2 years old, the low investment cost and pay
back a relatively short period makes this hybrid
system economically attractive, add to that, these
hybrid systems that combine to produce electricity
and hot water from one system in the same time [27].
Performance of a hybrid photovoltaic/thermal
(PV/T) under active solar
A simple design of hybrid (PV/T) double-slope active
solar still has been fined and its performance is
evaluated in field conditions, the solar energy
productively still can be improved by increasing the
temperature of the water in the solar energy is still
one of the parameters, where it has designed,
manufactured and evaluates the performance of a
hybrid photovoltaic thermal system (double slope of
the active solar still) and modifies the
photovoltaic/thermal (PV/T) dual-slope active solar
energy is still designed and fabricated to remote sites.
And under field conditions in the natural circulation
and forced mode (series and parallel), It had been
experimented evaluating performance in order to
improve the productivity of a dual slope solar energy
solar still [28]. The water pump has been used
between solar and photovoltaic (PV) integrated flat-
panel collector for re-circulation of water during the
collectors and converted into solar still, from Figure
3 noted that the daily energy efficiency of 17.4% was
gained for the parallel forced mode arrangement and
higher than the series (16.4%) and of the natural
circulation models (16.3%), still will produce a higher
yield than the other configurations and obtained as
7.54 kg/day for each hour exergy efficiency is also
found to be highest for the same shape and hit as high
as 2.3%. The comparative yield obtained is about 1.4
times higher than that obtained for hybrid (PV/T)
single slope, solar still, also found that the total cost
of the fabricated still is about 14% less than hybrids
(PV/T) single slope, solar still and the price will be
further reduced substantially once production is held
up on a commercial scale [29].
9
Figure 3. Hourly variation of thermal and exergy efficiencies of solar still during sunshine in different
functional styles of hybrid double slope active solar still [29]
Application simulation of solar heating on hybrid
photovoltaic/Thermal collectors (PVT)
To achieving the solar energy which can offer a
suitable solution for the electricity and heat in solar
panels and/or photovoltaic thermal panels because in
this system of electricity production is specially
priority for fields that do not have potential high solar
energy, where totally recognize that the cell
temperature affects on operate photovoltaic panels
and efficiency which limits the growth of
photovoltaic panels, Nevertheless, suggested one
good solution to analyze the hybrid operation of PV/T
integrated system that increase solar contributions
for electricity and useful thermal profits [10]. Based
on the energy and transfer of exergy analysis will use
cooling cell panel as a resolution in the photovoltaic
thermal (PV/T), where it is obtained on both
electricity and warmth (air and water) as the heating
fluid in the PV/T collectors which can be used for
heating purposes or in industrial applications, it is
necessary for the performance of PV modules at low
temperature will dilute the value of the gain heat and
the efficiency of exegetic will be very small [30].
Used TRNSYS platform simulation PV/T system,
cogeneration heating, established to look at the
system performance of solar PV/T where in a typical
day studied production of electrical energy from the
collector PV/T, heat consumption, the exit
temperatures of assistance the heat source and outlet
temperatures from the heat storage tank as Figure 4
below shows the change graphs inlet and outlet
temperature of PV/T collector work the fluid with
solar radiation intensity the ambient temperatures in
a typical day in the heating season. The average
temperature outdoors was - 4.6 ºC, and approach the
highest solar radiation intensity 370 W/m
2
, and the
difference in the inlet and outlet temperature of the
![Figure 9. Schematic diagram of double pass PV/T [33].](/figures/figure-9-schematic-diagram-of-double-pass-pv-t-33-taz6q4m5.webp)
![Figure 2. The PV cell temperature and efficiency evolutions [22]](/figures/figure-2-the-pv-cell-temperature-and-efficiency-evolutions-2j3xg39c.webp)
![Figure 4. Graphs of the inlet and outlet temperature of PV/T collector working fluid with solar radiation intensity [12]](/figures/figure-4-graphs-of-the-inlet-and-outlet-temperature-of-pv-t-12rcc4dy.webp)
![Figure 5. Graphs of heat consumption outlet temperatures of auxiliary heat source and outlet temperatures of the heat storage tank with outdoor ambient temperature [12]](/figures/figure-5-graphs-of-heat-consumption-outlet-temperatures-of-37ezhijl.webp)
![Figure 1. Field experimental results of the hybrid solar collector: (a) operating results of hybrid solar collector, (b) alternating current power generation, (c) heat fractions for domestic hot water supply [3]](/figures/figure-1-field-experimental-results-of-the-hybrid-solar-1171h3u6.webp)
![Figure 6. Spectral representation of the absorption, reflection and PV conversion of real c-Si solar cell [13]](/figures/figure-6-spectral-representation-of-the-absorption-2c2iybv5.webp)