Renewable and Sustainable Energy Reviews 60 (2016) 1430–1441
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Renewable and Sustainable Energy Reviews journal homepage: www.elsevier.com/locate/rser
A comprehensive review of Uniform Solar Illumination at Low Concentration Photovoltaic (LCPV) Systems Yasaman Amanlou a, Teymour Tavakoli Hashjin a,n, Barat Ghobadian a, G. Najafi a,nn, R. Mamat b a b
Biosystems Engineering Department, Tarbiat Modares University, Tehran, Iran Faculty of Mechanical Engineering/Automotive Engineering Centre, Universiti Malaysia Pahang, Pekan, Pahang, Malaysia
art ic l e i nf o
a b s t r a c t
Article history: Received 18 January 2015 Received in revised form 10 January 2016 Accepted 8 March 2016
Conventional high performance silicon solar cells have a potential to generate more electricity by using low concentrating reflectors. Static solar concentrators reduce the cost of photovoltaic systems for given electrical power demand. However, non-uniform illumination on the conventional rectangular photovoltaic panel causes ohmic drops, mainly due to the cell that operates locally at higher irradiance. In this research study a comprehensive review has been carried out regarding Uniform Solar Illumination at Low Concentration Photovoltaic (LCPV) Systems. Another objective of the present study is therefore, calculating the pattern of sun incident at low concentration ratios for reflective troughs (V-type, cylindrical and compound parabolic concentrators) and linear Fresnel reflectors. The geometrical parameters of these concentrators were studied to obtain uniform illumination on the common rectangular photovoltaic panels. The designed concentrator with most uniform flux distribution, high concentration ratio and low requirement of mirror was fabricated and tested at ambient conditions. The optical simulation output of different concentrators illustrated the linear Fresnel reflector had uniform irradiance on the photovoltaic panel with standard deviation less than 30% of total income radiation. The experimental results showed that the linear Fresnel reflector has the potential to harvest more energy when using standard silicon solar cells in a basic concentration configuration. Finally thermal, electrical and total performances of a photovoltaic/thermal flat collector were measured with and without concentrator. Using the concentrator improved thermal and overall efficiency by 16% and 17.5% respectively. The maximum overall efficiency for PVT collector with concentrator and without concentrator was 91% and 78% respectively. & 2016 Elsevier Ltd. All rights reserved.
Keywords: Reflective concentrator Optical simulation Electrical performance Conventional solar cell Low Concentration Photovoltaic (LCPV) System
Contents 1. 2.
3.
4.
n
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Optical characteristic . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.1. Concentration ratio . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.2. Uniformity definition. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Type of optics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3.1. Flat concentrators or V-trough . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3.2. Parabolic concentrator. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3.3. Cylindrical troughs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3.4. Linear Fresnel reflectors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Analysis different types of concentrators . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4.1. Flat concentrators . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4.2. Parabolic concentrator. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Corresponding author. Tel.: þ 0098 21 48292318; fax: þ 98 21 48292200. Corresponding author. Tel.: þ 98 21 48292322; fax: þ98 21 48292200. E-mail addresses:
[email protected] (T.T. Hashjin), g.najafi@modares.ac.ir (G. Najafi).
nn
http://dx.doi.org/10.1016/j.rser.2016.03.032 1364-0321/& 2016 Elsevier Ltd. All rights reserved.
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4.3. Cylindrical trough . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4.4. Linear Fresnel reflectors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5. Experimental device . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6. Experimental results . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7. Conclusions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Acknowledgment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
1. Introduction With the growing problems surrounding global warming, solar photovoltaic (PV) technology is getting more attraction for electricity generation. PV cells are semiconductor devices that have the ability to convert the energy available in both dispersed and concentrated solar radiation into direct current (DC) electricity [1]. The development of the photovoltaic technology in the last years has been fuelled by the implementation of various supporting strategies [2–18]. Solar energy is probably the strongest-growing electricity generation technology, demonstrating recent annual growth rates of around 37% [19]. However, the use of photovoltaic (PV) system is limited due to its prohibitively high cost. In a PV system, the PV cell material contributes about 50% of the total cost. Thus, one of effective measures to reduce the cost of electricity generated by a PV system is to reduce the use of solar cells for given power demand, and this can be achieved by solar concentrators [20–30]. Various types of concentrators can be classified according to their concentration ratio namely low, medium and high concentration systems [31,32]. Low concentration photovoltaic (LCPV) systems have the potential to reduce the cost per kWh of electricity compared to conventional flat-plate photovoltaic (PV) [33– 36]. For medium and high concentration ratio, concentrating PV system seems to be difficult to implement. High concentrating PV system needs specially designed solar cells, complicated suntracking device and cooling techniques to control the high temperature of cell [37]. In case of medium and high concentration, common Si wafer based solar cells are not suitable because of negative temperature coefficient whereas about 80% to 90% of PV cells manufactured worldwide are Si wafer based solar cells [38–40]. Low concentration photovoltaic (LCPV) systems can make use of conventional high performance silicon solar cells (made for 1 sun application) [41]. In this technology, the commercial Si solar cell is used under the concentration of 2 suns to 10 suns. Therefore, low concentrator optics in static or quasi-static mode, wherein the continuous suntracking system is eliminated, was widely interested. Nevertheless, the success of the LCPV technology depends on two conditions: the first is that the optical surface collecting the light and redirecting it to the cells had to be cheaper than the cell area in replace; and the second is that the efficiency of the cells under concentrated sunlight should not decrease substantially. Uniform illumination is affirmed by the second condition in case of flat plate modules. Different optical designs for solar concentrators have been recommended by some researchers to concentrate light into the focal point or line, but there is not sufficient information about uniform concentration on the rectangular flat plate. Despite extensive research has been carried out on linear and twodimensional concentrators, but rare studies have focused on the design of concentrators which illuminate a flat plate rectangular PV panels uniformly [42–45]. In this study a comprehensive review has been carried out regarding uniform solar illumination at low concentration
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photovoltaic (LCPV) Systems. Then pattern of sun incident has been calculated at low concentration ratios for different conventional concentrators and adapt concentrators geometry to obtain uniform illumination on the common rectangular PV panels. Finally the best type of concentrator has been fabricated and applied to photovoltaic/thermal (PV/T) flat plate collector and performance of the collector has been reported with and without used concentrator.
2. Optical characteristic 2.1. Concentration ratio There are several definitions of concentration ratio in use. The most common is “geometric concentration ratio”. This is defined as the area of the primary lens or mirror divided by the active cell area [46–53]. The active cell area is the region of the cell that is designed to be illuminated. The non-illuminated edge of the cell is often provided with bus bars for electrical connection, and this need not result in an efficiency loss as would be the case in a flatplate module. In the other word, definition of concentration ratio (C) is the addimentional ratio of the area of aperture (Aa ) to the area of the receiver (Ar ). C¼
Aa Ar
ð1Þ
Another measure of the concentration is intensity concentration, or “Suns”. Since standard peak solar irradiance is often set at 0.1 (W/cm2), the “suns” concentration is defined as the focused light on the cell active area divided by 0.1 (W/cm2) [54,55]. 2.2. Uniformity definition The purpose of the optical system is to concentrate sunlight and direct it to the solar cell uniformly, but this might be uneasiness by the optical element and solar tracking system [56]. The non-uniformity in illumination profile causes several problems in the functioning of the concentrated photovoltaic (CPV) system. The non-uniform illumination produces ohmic drops higher than expected, mainly due to the cell operates locally at higher irradiance [57–61]. In a uniformly illuminated solar cell it is found that an internal current flows even in open-circuit conditions, which is directly proportional to the irradiance and the degree of non-uniformity [62]. The cell irradiance non-uniformity decreases the open-circuit voltage (or, equivalently, increases the effective series resistance) of the cell, thereby reducing its photovoltaic conversion efficiency [63–66]. Concentrating sunlight onto the small solar cell causes localized thermal heating. Non-uniform temperature distribution on the cell affected the heat transfer from cell and negative temperature coefficient reduces the thermal performance.
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Irradiance uniformity is also important because not only the cell efficiency depends on it, but also to assure the long term cell and concentrator reliability [67]. Point focus or linear focus concentrators generate hot spot on the solar cell. Controlling hot spots on the solar cell is a great challenge for researchers. Zou and Yang [68] designed a combine concentrator to achieve high irradiance uniformity on the solar cell in a high-concentration photovoltaic module. They reported that the enhanced cell irradiance uniformity enables a PV module to gain an increased photovoltaic conversion efficiency of 28%. Zhuang and Yu [69] improved uniformity irradiance distribution on the solar cell without using secondary optical element (SOE) in the concentrator photovoltaic (CPV) system to increase the solar cell conversion efficiency. To measure the intensity of non-uniformity some statistical term such as Standard Deviation, Mean and difference between maximum and minimum incoming flux are employed [70,71]. In many cases, uniformity of irradiance just compare between flux distribution pattern. Inaccurate designed concentrators can reflect part of the sunlight out of the target absorber (PV cells). Therefore the criterion is needed to explain the efficiency of a given concentrator. The optical efficiency is defined as the fraction of the solar radiation reflecting by concentrator that is absorbed by the PV collector and is given as:
η¼
Q ab I b Aa
ð2Þ
Useful length of mirror (L) is dependent on reflector angle (α) and width of PV panel. The L would be calculate by trigonometric relationships for different amount of α. Following Eqs. (3, 4) define the relationships between parameters: π π ð3Þ β ¼ α α ¼ 2α 2 2 L¼W
sin 2α π2 sin π2 α
ð4Þ
Kostic et al. [75] surveyed the influence of reflectance from flat aluminum concentrators on energy efficiency of PV/Thermal collector (Fig. 2). The flat aluminum has a simple structure and resulted in appropriate enhancement of thermal and electrical efficiency. The flat concentrators are interesting for their uniform concentration, simple structure and low cost. However, low concentration ratio (usually lower than 3) limited their application [75–78]. Sangani and Solanki [79] designed and fabricated a V-trough (flat-mirror) photovoltaic concentrator system to assess PV electricity cost ($/W) reduction. The PV concentrator system had 2 suns concentration intensity. They developed their PV concentrator system for different types of tracking modes such as seasonal, one axis north-south and two axis tracing. This concentrator increases the output power by 44% as compared to PV flat-plate system for passive cooled modules.
Where, Q ab refers to the energy absorbed by receiver, I b is the energy incident on the aperture per unit area.
3. Type of optics Concentrator is an optical devise it able to concentrate a large area of sunlight onto a small area. Various types of solar concentrators have been developed in recent years and have been tested for their suitability for various processes. Concentrator optics can classified to refractive lenses and reflective dishes and troughs. Also, concentrator optics have categorized to point-focus which have circular symmetry about their axis and linear focus, in which the lens has a constant cross section along a transverse axis (focus the light into the line) [72]. Linear concentrators include troughs (V-type, cylindrical and compound parabolic concentrators) and linear Fresnel concentrators. Linear Concentrators concentrate sun light on a linear focus. Therefore, these concentrators can be used to illuminate a linear array of photovoltaic cells [73,74]. Point-focus concentrators concentrate parallel sun rays at one focal point. Point-focus lens usually have high concentration ratio and they can’t be used commercially to illuminate a flat plate rectangular PV panel. The architectural designs and optical principles for various solar reflective concentrators for the LCPV systems are presented in the following section.
Fig. 1. The scheme of flat reflector.
3.1. Flat concentrators or V-trough Using a flat-plate mirror to reflect more sunlight on a flat plate rectangular PV is the simplest method for uniform sunlight concentration [75–77]. The simple scheme of flat reflector is shown in Fig. 1. Angle of mirror with horizon (α) specifies the useful length of mirror (L). The useful length of mirror (L) equals the width of mirror, which enables to reflect whole received sunlight to the photovoltaic plate. β is the incidence angle of reflective beam to the panel.
Fig. 2. Schematic diagram of the PV/T collector with solar radiation concentrators [75].
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Mosalam-Shaltout et al. [80] studied the performance of a LCPV for a year and compared the results with the performance of simple PV system. This research showed a good improvement in PV performance which was equipped with a flat plate concentrator (V-trough). The concentration ratio at this research was about 1.6 and trough was full tracing.
concentration ability of the system with flat receiver and cylindrical receiver is quantitatively analyzed and compared. Taneja et al. [91] studied the optical performance of a seasonally adjusted circular cylindrical solar concentrator in detail, using
3.2. Parabolic concentrator One of the best investigated solar concentrators is the 2-D CPC trough (Fig. 3); which is the most efficient solar concentrator because of its characteristics of collecting and concentrating all the rays within a specified acceptance angle [81,82]. Sellami and Mallick [82] determined the theoretical optical efficiency and the optical flux distribution at the photovoltaic cell of a 3-D Crossed Compound Parabolic Concentrator (CCPC) for different incidence angles of light rays. It was found that the CCPC with a concentration ratio of 3.6 represents an improved geometry compared to a 3-D Compound Parabolic Concentrator (CPC) for its use as a static solar concentrator. With accurate calculation of the concentration ratio and specific geometry, it can obtain an appropriate uniformity of input flux on the linear array of cells [83–87]. In Fig. 4, F and V are the focus and vertex of parabola curve respectively. Focal length and parabola depth are specified with the letters f and h. Parabolic curve is obtained from Eq. (4): y2 ¼ 4fx
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ð4Þ
Fig. 4. The curve of parabola.
Guiqiang [88] has used compound parabolic concentrators (CPCs), as non-tracking concentrators, when concentration ratio is below 3. They also compared the performance of the common flat and solar concentrating PV/T systems. They observed a gradual reduction at the quantity of photovoltaic cells efficiently, but also provided a higher temperature heat for space heating or water heating (Fig. 5). 3.3. Cylindrical troughs Cylindrical trough is the part of a cylinder that is cut longitudinally so that its cross-sectional area is the sector of circle (Fig. 6). Factors involved in the design of cylindrical concentrators are: radius (R), depth (d) and angle towards the horizon (α). Nicolas and Duran [89] studied cylindrical concentrators for any incidence angle of the solar rays. Hongfei et al. [90] investigated the flat receiver and cylindrical receiver respectively as well as determining the relationship between the receiving beam and the incident ray. By light tracking simulation, the distribution, width, eccentric magnitude of the image, and efficiency of the concentrated light varying with the incident angle can be calculated and visualized. Furthermore, the
Fig. 3. Comparison between CCPC and 2-D CPC [82].
Fig. 5. PV/T-CPC module [88].
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three different absorber configurations. The effect of angle of incidence of direct solar radiation, mirror rim angle, absorber size, mirror shading and absorber defocusing/lateral shift on the concentration characteristics was evaluated for the three absorber configurations. Cylindrical trough is not popular to concentrate light on a line since its geometrical properties. If their design is not accurate, two blurred focal line will occurr. This property limited the usage of cylindrical troughs to concentrate light on linear absorber in one hand. At the other hand, it inspires an idea making a concentrator for a flat plate PV.
inclination of each mirror element with respect to the base of the concentrator and the width of the mirror element are determined so that incident solar radiation, after reflection, is intercepted within the absorber and, hence, illuminates the absorber from one end to the other. The approach allows a variation in the width of the constituent mirror elements. In the second approach, the concentrator is generated from a prespecified equal width of the mirror elements and an appropriate size of the absorber which will intercept all the solar energy reflected from the constituent mirror elements and which is determined for the desired aperture of the concentrator.
3.4. Linear Fresnel reflectors A Fresnel typical solar concentrator is a linear Fresnel reflector solar concentrator (LFRSC). This type of concentrators is made of a series of long plane mirror elements positioned parallel on a framework. The angle of inclination of each mirror element with respect to the base of the concentrator is variable. An appropriate space is introduced between two consecutive mirror elements in order to avoid blocking of solar radiation reflected from the subsequent mirror elements. From the fabrication point of view, the concentrator is very simple and inexpensive [92–94]. However, the disadvantage of this concentrator is that because of the space introduced between the mirror elements, only a fraction of the base area of the concentrator covered by reflecting surfaces contributes to the concentration on the surface of the absorber. Nevertheless, when mounted on a simple framework, the existence of the gaps between the mirror elements offers an advantage, when considering that wind loading can be considerably reduced. Two different approaches have been proposed for designing LFRSC [95]. In one approach, the concentrator is generated from the prespecified size of the absorber. In this approach, the angle of
4. Analysis different types of concentrators In this study, the Monte Carlo ray tracing method (MCRTM) was employed to evaluate the optical performance and flux distribution on the receiver (PV panel). The MCRTM can perform well with a good agreement in dealing with special complex geometry problems [96,97] and it is a technique that computes the outcome of random processes [98]. Optical analysis was carried out based on the following assumption: Reflecting surfaces ideal and free from fabrication errors; the transmittance, reflectance and absorbance of the receiver (PV panel) are constant. The MCRTM reduces the volume of huge data and simulation time [99]. The optical performance was predicted by aggregating the result of several beams being traced. 1000 radiation sources were randomly distributed over the width of the aperture. Although in all calculations width (W) and height (H) of receiver are equal to 80 and 100 cm (common width of commercial fortyfour arrays PV panels) respectively. Thus at each simulation a pair of known concentrator have taken place at lateral sides of PV panel. Incoming light is normal to the PV panel and trough axis. 4.1. Flat concentrators
Fig. 6. Cylindrical trough cross section.
Different length of flat mirror and its angle effect on the concentration ratio was studied (Fig. 7). The calculated values of L and C for different amount of α are listed in Table (1). The results showed that by increasing the angle of the mirrors from horizon (α), the concentration ratio would be increased, though, it does not exceed 3. Actually, to achieve concentration ratio more than 2, the required length of the mirror increases rapidly. Therefore, manufacturing cost grows rapidly instead small C incensement.
Fig. 7. Pattern of irradiation and irradiation intensity on a 80 100 cm PV collector that illuminated by flat concentrator.
Y. Amanlou et al. / Renewable and Sustainable Energy Reviews 60 (2016) 1430–1441
Optical simulation indicates that flat concentrators make a uniform distribution of irradiation on the absorber. Fig. 7 illustrates optical simulation of the flat concentrator at 60 degree (C ¼2) when incoming flux is 1200 W/m2. Due to refractive characteristic of glass which covers the PV collector, a little bit of nonuniformity occurs at some angles of the mirror. To surmount very low concentration ratio of flat concentrators, Butler et al. [36] employed a four-facet flat reflector (Fig 8). Using this, technique they could achieve geometric concentration ratio of C ¼3 in theory and actual concentration ratio of C ¼2.68 when taking reflectivity into account. Their idea is very close to using Fresnel parallel reflective elements. 4.2. Parabolic concentrator The most effective factor that is involved in the design of the parabolic curve is the focal length (Fig. 9). By increasing the focal length, the aperture length increases. Since the concentration ratio is calculated using aperture area divided by the area of the receiver, therefore on increasing the focal length, concentration ratio is enhanced. By varying the depth and focal length, various patterns of reflection have been occurring. For instance, look at Fig. 10 and Table 2. A parabolic concentrator with a focal length of 40 cm, irradiance light on the PV plate is more uniform than when the focal length is 30 cm.Geometric concentration ratio (C) is 4 when focal length is 40 cm, also as Table 2 shows, the maximum and average irradiation are 2021 and 1294, respectively. These figures indicate that the concentrator cannot concentrate sun light as much as the theoretical concentration ratio. By decreasing focal length from 40 to 30 cm, the maximum irradiation reaches to 5261 (W/m2), but uniformity of irradiation on PV plate decreases rapidly. Overall, studying more states, it is found that, larger focal length increases the uniformity of irradiation and decreases the received sunlight. It also smaller focal length decreases the
theoretical concentration ratio and non-uniformity. This characteristic of parabolic concentrators makes them suitable to collecting sunlight on the linear absorber not plates. 4.3. Cylindrical trough The effect of radius (R), depth (d) and angle (α) has been studied on irradiation intensity and pattern in cylindrical trough (Fig 11). The results indicated that the angle has a great impact on the received maximum radiation and uniformity. For example, when radius and depth are 60 and 20 cm, respectively, by varying angle from 30 to 70 degree, average and maximum incident rays are changing dependently (Table 3). When angle towards the horizon equals 60 degree, both of maximum and average radiation obtains the maximum value. (Table 4) 4.4. Linear Fresnel reflectors The impacts of the width and the number of parallel mirrors (as Fresnel reflector Fig. 12) on the intensity of the radiation pattern have been analyzed. In Fig. 13, the simulation results can be seen in four various numbers of parallel mirrors.
Table 1 The calculated values of useful length (L) and concentration ratio (C) in flat concentrators (W ¼ 80 cm). α (degree)
L (cm)
C
50 60 70 80
22 80 180 433
1.35 2 2.53 2.89
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Fig. 9. Parabolic concentrator.
Fig. 8. Low concentration ratio flat concentrator with 4 flat reflectors [36].
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Fig. 10. Pattern of irradiation and irradiation intensity on a 80 100 cm PV collector that illuminated by CPC. (a) the focal length ¼ 30 cm and (b) the focal length¼ 40 cm. Table 2 Optical characteristics of parabolic concentrator.
Table 4 Optical characteristics of Fresnel concentrators.
Focal length (cm)
Geometric concentration ratio (C)
Maximum flux (W/m2)
Average flux (W/ m2)
Standard Deviation
Optical efficiency (%)
Number of parallel mirrors
Width of Maximum each mir- flux (W/m2) ror (cm)
Average flux (W/ m2)
Standard Deviation
Optical efficiency (%)
30 40
4 4
5261 2021
2587.5 1294.54
1013.75 141.81
64.7 32.4
2 3 4 5
40 40 20 20
2007.5 2112.5 2140 2497.5
457.125 414.687 830.5 757.25
83.6 88 89.1 91.3
pair pair pair pair
2745 2882 3453 3782
Fig. 11. cylindrical trough. Table 3 Maximum and average incident rays on a 80 100 cm PV collector that illuminated by cylindrical trough at different angles. 2
Fig. 12. Linear Fresnel reflectors.
2
Radius (cm)
depth(cm)
α(degree)
Maximum(W/m )
Average(W/m )
160 160 160 160
20 20 20 20
30 45 60 70
1882 2492 4278 4024
1367 2021 3199 3087
number cause the pattern that looks like cylindrical reflectors. Despite this, uniformity of Fresnel reflectors is better than cylindrical troughs for the same concentration ratio.
5. Experimental device The results of optical simulation indicated that increasing the number of mirrors and decreasing their width, increases light intensity on the PV panel. Likewise, an increase in maximum irradiation and non-uniformity are the result of high degree of intensity. Generally, few number of wider mirrors cause the uniform pattern of irradiation looks like a flat concentrator. On the other hand, reducing the width of the mirror and increasing their
The simulation results of the different designs of concentrators were compared with each other and the best design with most uniform flux distribution, high concentration ratio and low requirement of mirror was chosen in this research work. In order to verify the optical simulation results, linear Fresnel reflectors with five pair of 20 cm width mirrors was fabricated and evaluated under ambient condition. Due to recovery of waste heat in the PV
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Fig. 13. Pattern of irradiation and irradiation intensity on a 80 100 cm PV collector that illuminated by Linear Fresnel concentrator,(a) two pair of 40 cm width mirror, (b) three pair of 40 cm width mirror, (c) five pair of 20 cm width mirror and (d) six pair of 20 cm width mirror.
panel, a hybrid photovoltaic/thermal (PVT) solar collector was used. Hybrid PVT system, which simultaneously converts solar radiation to thermal and electrical power, was increasingly considered. The results of various studies have shown that such hybrid systems are more efficient in comparison with both individual photovoltaic and thermal systems [100–104]. To examine the effect of using linear Fresnel concentrator, the PVT collector which has been successfully tested by Mortezapour et al. [105] was employed. This PVT collector with fabricated concentrator is shown in Fig. 14. The frame of the mirrors is adjustable to adapt the mirror angles for seasonal solar tracking. Tests were performed in Tehran, Iran. The PV solar collector was installed at a tilt angle of 43° equal to the latitude of the city. The solar collector has a wooden duct of dimensions 1.05, 0.805 and 0.1 m that is glazed by a glass layer and the PV module is positioned equidistant from the glazing glass and the bottom insulator of the duct. The bottom insulation consisted of wood and glass wool [106]. The mass flow rate of inlet air was constant for all tests and it was 0.02 kg/s.
The tests were carried out in the month of September from 9 am to 15 pm. The PV module was a single-crystalline silicon and its characteristics at standard testing condition were: open circuit voltage Voc ¼30 V, short-circuit current Isc ¼ 4 A, electrical efficiency 12%. To monitor the PV panel temperature as an effect of irradiation distribution, 9 temperature sensors were attached to the back surface of the PV panel. In order to measure the temperature of inlet and outlet flowing, two temperature sensors (SMT 160) were installed before and after the collector duct. Simultaneously, a solar power meter (TES 1333 R) measured the solar radiation intensity on the collector surface, during the test. A multimeter (DEC330FC) was used to measure the open circuit voltage (Voc) and short circuit current (Isc).
6. Experimental results The hourly variation of solar radiation intensity for a typical day of September 2014 under the condition of Tehran, from 9 a.m. to
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Fig. 14. Fabricated concentrator and PVT collector.
Fig. 15. Hourly variation of solar radiation intensity for a typical day September 2014 under the condition of Tehran.
3 p.m. is denoted in Fig. 15. The solar radiation intensity varied from 589 W/m2 at 9:00 to 1019 W/m2 at 12:30. In order to evaluate the performance of collector assisted by linear Fresnel concentrator, the PVT collector was studied under typical solar intensity and the results were compared with those from PVT collector stand-alone (without concentrator). The CPV/T system performance is combination of the two parts’ performance: Photovoltaic conversion and thermal utilization [107]. Power generation of the PV device under concentrated illumination condition can be expressed as PPV ¼ APV :FF:VOC :ISC
ð3Þ
where APV is the total area of the PV devices in the CPV/T system; FF, VOC and ISC are the fill factor, open circuit voltage and shortcircuit current of the solar cell under concentration condition, respectively. Thermal performance of a solar collector is described by an energy balance that indicates the distribution of incident solar energy into useful energy gain thermal losses and optical losses. In steady state the useful energy output of a flat plate collector of area APV is difference between the absorbed solar radiation and thermal loss: Q th ¼ APV ½S UL ðTPV Ta Þ
ð4Þ
Fig. 16. Electrical performance of PVT collector with and without concentrators.
where S is solar energy absorbed by collector per unit area of absorber; UL is coefficient of thermal energy lost from collector; TPV and Ta are the mean absorber plate temperature and ambient temperature, respectively [72]. Fig. 16 shows the performance of collector with and without concentrators. Almost in all points, electrical performance of collector which is assisted by concentrator is higher but around the noon the performance of collector without concentrator is little more than the performance of concentrator assisted collector. This problem occurs because of PV temperature profile. The cell temperature grows with an increase in concentration of light and being a semiconductor material, it has a negative temperature coefficient of open-circuit voltage. At the noon, the mean temperature of PV and standard division of temperature distribution are more than the other times. Nevertheless, using concentrator can improve the electrical performance by 4.22 percent. Thermal performance and overall performance are presented in Figs. 17 and 18. Using concentrator improves thermal and overall efficiency by 40.2 and 36 percent respectively. The maximum overall performance for PVT collector with concentrator and without concentrator is 2185 (W) and 1413 (W) respectively. Sangani and Solanki [79] reported that a concentrator with geometric concentration ratio of 2 and tracking system could improve the output power by 44%.
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3. Cylindrical concentrators with large radius and shallow depth have uniform pattern of reflecting light. Compromising between radius, depth and angle; uniform illumination is available. 4. Fresnel linear reflectors which have more number of parallel mirror by narrow width reflect the light same as cylindrical reflectors. Usually the low cost of manufacturing is the main criteria to select this type of concentrators. Also the pick of solar radiation intensity plays a main rule in the decrement of electrical efficiency. 5. The experimental findings show that LCPV has the potential to harvest more energy when using standard Si solar cells in a basic concentration configuration as used in this study. Using concentrator improves thermal and overall efficiency by 4.22%, 40.5% and 36% respectively.
Acknowledgment Fig. 17. Thermal performance of PVT collector with and without concentrators.
The authors acknowledge the financial support of Tarbiat Modares University (TMU) renewable laboratories authorize and Iranian fuel conservation company (IFCO) to carry out this investigation.
References
Fig. 18. Overall performance of PVT collector with and without concentrators.
In comparison with the results obtained from stand-alone collector, the concentrated PV panel has a higher mean surface temperature. The fabricated linear Fresnel reflector with four pair of 20 cm width mirror doesn’t change temperature distribution on the PV until solar radiation intensity is lower than 850 W/m2. When solar radiation intensity reaches to 1012 W/m2, the standard deviation of temperature distribution on the concentrated PV surface increases 30% as compared with non-concentrated collector. This result shows a good agreement with the simulated results.
7. Conclusions The conclusion drain from the results achieved from optical simulation of four type of low concentration reflectors namely flat, parabolic, cylindrical and Fresnel; forward sentences are as follow: 1. Flat concentrators make the most uniform irradiation pattern at the angle of 60 degree (C ¼2). Concentration ratio hardly increases more than 2, therefore, cannot accumulate very much sunlight on the PV panel. 2. Parabolic concentrators increase the maximum intensity, but they create a non-uniform pattern of light. This problem would be worsen if the focal length is small. This type of concentrator is inappropriate to concentrate the sunlight on the rectangular PV plate.
[1] Makki A, Omer S, Sabir H. Advancement in hybrid photovoltaic systems for enhanced solar cells performance. Renew Sustain Energy Rev 2015;41:658–84. [2] Grossmann WD, Grossmann I, Steininger KW. Solar electricity generation across large geographic areas, Part II: A Pan-American energy system based on solar. Renew Sustain Energy Rev 2014;32:983–93. [3] Gaetani M, Huld T, Vignati E, Monforti-Ferrario F, Dosio A, Raes F. The near future availability of photovoltaic energy in Europe and Africa in climateaerosol modeling experiments. Renew Sustain Energy Rev 2014;38:706–16. [4] Abdul-Hamid S, Othman MY, Sopian K, Zaidi SH. An overview of photovoltaic thermal combination. Renew Sustain Energy Rev 2014;38:212–22. [5] Ming Z, Shaojie O, Hui S, Yujian G. Is the “Sun” still hot in China? The study of the present situation, problems and trends of the photovoltaic industry in China Renew Sustain Energy Rev 2015;43:1224–37. [6] Mundo-Hernández J, Alonso BC, Hernández-Álvarez J, Celis-Carrillo B. An overview of solar photovoltaic energy in Mexico and Germany. Renew Sustain Energy Rev 2014;31:639–49. [7] Alimi SE, Maatallah T, Ben Nasrallah S. Break-even analysis and optimization of a stand-alone hybrid system with battery storage for residential load consumption: a case study. Renew Sustain Energy Rev 2014;37:408–23. [8] Alharbi FH, Kais S. Theoretical limits of photovoltaics efficiency and possible improvements by intuitive approaches learned from photosynthesis and quantum coherence. Renew Sustain Energy Rev 2015;43:1073–89. [9] Lin J, Wen P, Feng C, Lin S, Ko F. Policy target, feed-in tariff, and technological progress of PV in Taiwan. Renew Sustain Energy Rev 2014;39:628–39. [10] Halabi MA, Al-Qattan A, Al-Otaibi A. Application of solar energy in the oil industry: current status and future prospects. Renew Sustain Energy Rev 2015;43:296–314. [11] Siddiqui MU, Said SAM. A review of solar powered absorption systems. Renew Sustain Energy Rev 2015;42:93–115. [12] Date A, Date A, DixonC, Akbarzadeh A. Progress of thermoelectric power generation systems: prospect for small to medium scale power generation. Renew Sustain Energy Rev 2014;33:371–81. [13] Byrne J, Taminiau J, Kurdgelashvili L, Kim KN. A review of the solar city concept and methods to assess rooftop solar electric potential, with an illustrative application to the city of Seoul. Renew Sustain Energy Rev 2015;41:830–44. [14] Dusonchet L, Telaretti E. Comparative economic analysis of support policies for solar PV in the most representative EU countries. Renew Sustain Energy Rev 2015;42:986–98. [15] Hernández-Moro J, Martínez-Duart JM. Economic analysis of the contribution of photovoltaics to the decarbonization of the power sector. Renew Sustain Energy Rev 2015;41:1288–97. [16] Wong J, Lim YS, Tang JH, Morris E. Grid-connected photovoltaic system in Malaysia: a review on voltage issues. Renew Sustain Energy Rev 2014;29:535–45. [17] Paiano A. Photovoltaic waste assessment in Italy. Renew Sustain Energy Rev 2015;41:99–112. [18] Kumar A, Baredar P, Qureshi U. Historical and recent development of photovoltaic thermal (PVT) technologies. Renew Sustain Energy Rev 2015;42:1428–36.
1440
Y. Amanlou et al. / Renewable and Sustainable Energy Reviews 60 (2016) 1430–1441
[19] 〈〈https://en.wikipedia.org/wiki/Growth_of_photovoltaics〉. [20] Tang R, Liu X. Optical performance and design optimization of V-trough concentrators for photovoltaic application. Sol Energy 2011;85:2154–66. [21] Tyagi VV, Kaushik SC, Tyagi SK. Advancement in solar photovoltaic/thermal (PV/T) hybrid collector technology. Renew Sustain Energy Rev 2012;16 (3):1383–98. [22] Daghigh R, Ruslan MH, Sopian K. Advances in liquid based photovoltaic/ thermal (PV/T) collectors. Renew Sustain Energy Rev 2011;15(8):4156–70. [23] Zondag H. Flat-plate PV–Thermal collectors and systems: a review. Renew Sustain Energy Rev 2008;12(4):891–959. [24] Hasan MA, Sumathy K. Photovoltaic thermal module concepts and their performance analysis: a review. Renew Sustain Energy Rev 2010;14 (7):1845–59. [25] Zhang X, Zhao X, Smith S, Xu J, Yu X. Review of R&D progress and practical application of the solar photovoltaic/thermal(PV/T)technologies. Renew Sustain Energy Rev 2012;16(1):599–617. [26] Chemisana D. Building integrated concentrating photovoltaics: a review. Renew Sustain Energy Rev 2011;15(1):603–11. [27] Zahedi A. Review of modeling details in relation to low-concentration solar concentrating photovoltaic. Renew Sustain Energy Rev 2011;15(3):1609–14. [28] Vivar M, Clarke M, Pye J, Everett V. A review of standards for hybrid CPV– thermal systems. Renew Sustain Energy Rev 2012;16(1):443–8. [29] Singh B, Othman MY. A review on photovoltaic thermal collectors. J Renew Sustain Energy 2009;1(6):062702. [30] Chong K, Lau S, Yew T, Tan P. Design and development in optics of concentrator photovoltaic system. Renew Sustain Energy Rev 2013;19:598–612. [31] Tripanagnostopoulos Y, Souliotis M, Tselepis S, Dimitriou V, Makris Th. Design and performance aspects for low concentration photovoltaics, 20thEUPVSEC, 6 10, Barcelona, Spain; 2005. [32] Luque A, Andreev V. Concentrator photovoltaics. 1sted. Berlin, Heidelberg, NewYork: Springer; 2007 Chapter:1and6. [33] Fraas L, Avery J, Huang H. Efficient solar photovoltaic mirror modules for half the cost of today's planar modules, in: International Conference on Solar Concentrators for the Generation of Electricity or Hydrogen, 2005, p. 33. [34] Lushetsky J. Accelerating innovation in solar technologies, in: SPIE Photonics Innovation Summit, US Department of Energy, 2008. [35] Kurtz S. A bright future for CPV, in: CPV Today CPV Summit, 2009. [36] Butler BA, van Dyk EE, Vorster FJ, Okullo W, Munji MK, Booyson P. Characterization of a low concentrator photovoltaics module. Physica B 2012;407:1501–4. [37] Perez-Higueras P, Munoz E, Almonacid G, Vidal PG. High concentrator photovoltaics efficiencies: present status and forecast. Renew Sustain Energy Rev 2011;15l:1810–5. [38] Yadav P, Tripathi B, Rathod S, Kumar M. Real-time analysis of lowconcentration photovoltaic systems: a review towards development of sustainable energy technology. Renew Sustain Energy Rev 2013;28:812–23. [39] Gerbinet S, Belboom S, Léonard A. Life Cycle Analysis (LCA) of photovoltaic panels: a review. Renew Sustain Energy Rev 2014;38:747–53 Silicon. [40] Rahman MZ. Advances in surface passivation and emitter optimization techniques of c-Si solar cells. Renew Sustain Energy Rev 2014;30:734–42. [41] Tripathi B, Yadav P, Lokhande M, Kumar M. Feasibility study of commercial silicon solar PV module based low concentration photovoltaic system. Int J Electrical Electronics Eng Res 2012;2(3):84–93. [42] Yeh PY, Yen PC, Yen JY, Wu TT, Lui PL, Wu CL, et al. Focal point tracking system for concentration solar power collection. Renew Sustain Energy Rev 2011;15(6):3029–33. [43] Mohammed YS, Mustafa MW, Bashir N. Status renewable energy consumption and developmental challenges in Sub-Sahara Africa. Renew Sustain Energy Rev 2013;27:453–63. [44] Mohammed YS, Mustafa MW, Bashir N. Hybrid renewable energy systems for off-grid electrical power: review of substantial issues. Renew Sustain Energy Rev 2014;35:527–39. [45] Tsikalakis A, Tomtsi T, Hatziagyriou ND, Poullikkas A, MalamateniosCh, Giakoumelos E, et al. Review of best practices of solar electricity resources application in selected Middle East and North Africa (MENA) countries. Renew Sustain Energy Rev 2011;15(6):2838–49. [46] Chen WH, Wang CC, Hung CI, Yang CC, Juang RC. Modeling and simulation for the design of thermal-concentrated solar thermoelectric generator. Energy 2014;64:287–97. [47] Kraemer D, Poudel B, Feng HP, Caylor JC, Yu B, Yan X, et al. Highperformance flat-panel solar thermoelectric generators with high thermal concentration. Nat Mater 2011;10:532–8. [48] Chen G. Theoretical efficiency of solar thermoelectric energy generators. J Appl Phys 2011;109:104908. [49] Jiang S, Hu P, Mo S, Chen Z. Optical modeling for a two-stage parabolic trough concentrating photovoltaic/thermal system using spectral beam splitting technology. Sol Energy Mat Sol Cells 2010;94:1686–96. [50] Banos R, Manzano-Agugliaro F, Montoya FG. Optimization methods applied to renewable and sustainable energy: a review. Renew Sustain Energy Rev 2011;15(4):1753–66. [51] Rodrigo P, Fermandez EF, Almonacid F, Perez-Higueras. Review of methods for the calculation of temperature in high concentration photovoltaic modules for electrical characterization. Renew Sustain Energy Rev 2014; 38: 478488.
[52] Xie WT, Dai YJ, Wang, Sumathy K. Concentrated solar energy applications using Fresnel lenses: a review. Renew Sustain Energy Rev 2011;15(6):2588– 606. [53] Kumar V, Shrivastava RL, Untawale SP. Fresnel lens: a promising alternative of reflectors in concentrated solar power. Renew Sustain Energy Rev 2015;44:376–90. [54] Ho CK, Iverson BD. Review of high-temperature central receiver designs for concentrating solar power. Renew Sustain Energy Rev 2014;29:835–46. [55] Luque A, Hegedus S. Handbook of photovoltaic science and engineering. 2nd ed. New York: John Wiley & Sons Ltd; 2011. [56] Ryu K, Rhee J, Park KM, Kim J. Concept and design of modular Fresnel lenses for concentration solar PV system. Sol Energy 2006;80:1580–7. [57] Baig H, Heasman KC, Mallick TK. Non-uniform illumination in concentrating solar cells. Renew Sustain Energy Rev 2012;16:5890–909. [58] Ma T, Yang H, Zhang Y, Lu L, Wang X. Using phase change materials in photovoltaic systems for thermal regulation and electrical efficiency improvement: A review and outlook. Renew Sustain Energy Rev 2015;43:1273–84. [59] Sahay A, Sethi VK, Tiwari AC, Pandey M. A review of solar photovoltaic panel cooling systems with special reference to Ground coupled central panel cooling system (GC-CPCS). Renew Sustain Energy Rev 2014;42:306–12. [60] Garcia-Heller V, Paredes S, Ong CL, Ruch P, Michel B. Exergoeconomic analysis of high concentration photovoltaic thermal co-generation system for space cooling. Renew Sustain Energy Rev 2014;34:8–19. [61] Shan F, Tang F, Cao L, Fang G. Performance evaluations and applications of photovoltaic–thermal collectors and systems. Renew Sustain Energy Rev 2014;33:467–83. [62] Luque A, Sala G, Arboiro JC. Electric and thermal model for non-uniformly illuminated concentration cells. Sol Energy Mat Sol Cells 1998;51:269–90. [63] Parida B, Iniyan S, Goic R. A review of solar photovoltaic technologies. Renew Sustain Energy Rev 2011;15(3):1625–36. [64] Abdin Z, Alim MA, Saidur R, Islam MR, Rashim W, Mekhilef A, et al. Solar energy harvesting with the application of nanotechnology. Renew Sustain Energy Rev 2013;26 (837-352). [65] Cuevas A, Lopez-Romero S. The combined effect of non-uniform illumination and series resistance on the open-circuit voltage of solar cells. Sol Cells 1984;11:163–73. [66] Bagienski W, Kinsey GS, Liu M, Nayak A, Garboushian V. Open circuit voltage temperature coefficients vs. concentration: Theory, indoor measurements, and outdoor measurements. In: Proceedings of the 8th International Conference on Concentrating Photovoltaic Systems (CPV-8), 2012. Toledo, Castilla–La Mancha, Spain, pp. 148–151. [67] Deshkar SN, Dhale SB, Mukherjee JS, Sudhakar Babu T, Rajasekar N, Solar PV. array reconfiguration under partial shading conditions for maximum power extraction using genetic algorithm. Renew Sustain Energy Rev 2015;43:102–10. [68] Zou YH, Yang TS. Optical performance analysis of a HCPV solar concentrator yielding highly uniform cell irradiance. Sol Energy 2014;107:1–11. [69] Zhuang Zh Yu F. Optimization design of hybrid Fresnel-based concentrator for generating uniformity irradiance with the broad solar spectrum. Opt Laser Technol 2014;60:27–33. [70] Salome A, Chhel F, Flamant G, Ferriere A, Thiery F. Control of the flux distribution on a solar tower receiver using an optimized aiming point strategy: application to THEMIS solar tower. Sol Energy 2013;94:352–66. [71] Delatorre J, Bau G, Bezian JJ, Blanco S, Caliot C, Cornet JF, et al. Monte Carlo advances and concentrated solar applications. Sol Energy 2014;103:653–81. [72] Duffie JA, Beckman WA. Solar engineering of thermal processes. 4th ed. New York: John Wiley & Sons; 2013. [73] Ibrahim A, Othman MY, Ruslan MH, Mat S, Sopian K. Recent advances in flat plate photovoltaic/thermal (PV/T) solar collectors. Renew Sustain Energy Rev 2011;15:352–65. [74] Palaskar VN, Deshmukh SP. A critical review on enhancement in system performance of flat plate hybrid PV/T solar collector system. Int J Energy 2013;3:395–403. [75] Kostic TK, Pavlovic TM, Pavlovic ZT. Influence of reflectance from flat aluminum concentrators on energy efficiency of PV/Thermal collector. Appl Energy 2010;87:410–6. [76] Mullick SC, Malhotra A, Nanda SK. Optimal geometries of composite plane mirror cusped linear solar concentrator with flat absorber. Sol Energy 1988;40:443–56. [77] Pancotti L. Optical simulation model for flat mirror concentrators. Sol Energy Mater Sol Cells 2007;9:551–9. [78] Meng X, Xia X, Sun C, Dai G. Optimal design of symmetrical two-stage flat reflected concentrator. Sol Energy 2013;93:334–44. [79] Sangani CS, Solanki CS. Experimental evaluation of V-trough (2 suns) PV concentrator system using commercial PV modules. Sol Energy Mater Sol Cells 2007;9:453–9. [80] Mosalam Shatout MA, Ghettas A, Sabry M. V-trough concentrator on a photovoltaic full tracking system in a hot desert climate. Renew Energy 1995;6:527–32. [81] Rabl A. Optical and thermal-properties of compound parabolic concentrators. Sol Energy 1976;18:497–511. [82] Sellami N, Mallick TK. Optical efficiency study of PV Crossed Compound Parabolic Concentrator. Appl Energy 2013;102:868–76.
Y. Amanlou et al. / Renewable and Sustainable Energy Reviews 60 (2016) 1430–1441
[83] Al-Alili A, Hwang Y, Radermacher R, Kubo I. A high efficiency solar air conditioner using concentrating photovoltaic/thermal collectors. Appl Energy 2012;93:138–47. [84] Mallick TK, Eames PC, Hyde TJ, Norton B. The design and experimental characterisation of an asymmetric compound parabolic photovoltaic concentrator for building facade integration in the UK. Sol Energy 2004;77:319–27. [85] Saxena A, Varun, El-Sebaii AA. A thermodynamic review of solar air heaters. Renew Sustain Energy Rev 2015;43:863–90. [86] Sellami N, Mallick TK, McNeil DA. Optical performance modeling of a typical 3D crossed compound parabolic photovoltaic concentrator using ray trace technique. In: 6th Photovoltaic science applications and technology. Southampton UK; 2010. p. 153–157. [87] Sarmah N, Richards BS, Mallick TK. Evaluation and optimization of the optical performance of low-concentrating dielectric compound parabolic concentrator using ray-tracing methods. Appl Opt 2011;50:3303–10. [88] Guiqiang L, Gang P, Su Y, Xi Z, Jie J. Preliminary study based on buildingintegrated compound parabolic concentrators (CPC) PV/thermal technology. Energy Procedia 2012;14:343–50. [89] Nicolas RO, Duran JC. Generalization of the two-dimensional optical analysis of cylindrical concentrators. Sol Energy 1980;25:21–31. [90] Hongfei Z, Tao T, Jing D, Huifangl K. Light tracing analysis of a new kind of trough solar concentrator. Energy Convers Manag 2011;52:2373–7. [91] Taneja P, Mathur SS, Kandpal TC. Optical performance analysis of a seasonally adjusted circular cylindrical solar concentrator. Energy Convers Manag 1991;31:353–67. [92] Historical development of concentrating solar power technology to generate clean electricity efficiently: A review. Renew Sustain Energy Rev 2015; 41: 996–1027. [93] Pavlovic TM, Radonjic IS, Milosavljevic DD, Pantic LS. A review of concentrating solar power plants in the world and their potential use in Serbia. Renew Sustain Energy Rev 2012;16(6):3891–902. [94] Reddy VS, Kaushik SC, Ranjan KR, Tyagi SK. State-of-art of solar thermal power plants: a review. Renew Sustain Energy Rev 2013;27:258–73. [95] Sharaf OZ, Orhan MF. Concentrated photovoltaic thermal (CPVT) solar collector systems: Part II: Implemented systems, performance assessment, and future directions. Renew Sustain Energy Rev 2015;50:1566–633.
1441
[96] Garcia P, Ferriere A, Bezian JJ. Codes for solar flux calculation dedicated to central receiver system application: a comparative review. Sol Energy 2008;82:189–97. [97] Huang X, Yuan Y, Shuai Y, Li B, Tan H. Development of a multi-layer and multi dish model for the multi-dish solar energy concentrator system. Sol Energy 2014;107:617–27. [98] Lin M, Sumathy K, Dai YJ, Zhao XK. Performance investigation on a linear Fresnel lens solar collector using cavity receiver. Sol Energy 2014;107:50–62. [99] Li X, Dai YJ, Li Y, Wang RZ. Comparative study on two novel intermediate temperature CPC solar collectors with the U-shape evacuated tubular absorber. Sol Energy 2013;93:220–34. [100] Chen HH, Hernandez CE, Huang TC. A study of the drying effect on lemon slices using a closed-type solar dryer. Sol Energy 2005;78:97–103. [101] Kalogirou SA. Use of TRNSYS for modelling and simulation of a hybrid PV– thermal solar system for Cyprus. Renew Energy 2001;23:247–60. [102] Punlek C, Pairintra R, Chindaraksa S, Maneewan S. Simulation design and evaluation of hybrid PV ¼ T assisted desiccant integrated HA-IR drying system (HPIRD). Food Bioproducts Process 2009;87:77–86. [103] Sandnes B, Rekstad J. A photovoltaic-thermal (PV-T) collector with a polymer absorber plate: experimental study and analytical model. Sol Energy 2002;72:63–73. [104] Nayak S, Kumar A, Mishra J, Tiwari GN. Drying and testing of mint (Menthapiperita) by a hybrid photovoltaic–thermal (PVT)-based greenhouse dryer. Dry Tech 2011;29:1002–9. [105] Mortezapour H, Ghobadian B, Minaei S, Khoshtaghaza MH. Saffron drying with a heat pump-assisted hybrid photovoltaic-thermal solar dryer. Dry Tech 2012;30:560–6. [106] Mortezapour H, GhobadianB, Khoshtaghaza MH, Minaei S. Photovoltaic/ thermal solar collector. J Agric Sci Technol 2012;14:767–80. [107] Liu Y, Hu P, Zhang Q, Chen Z. Thermodynamic and optical analysis for a CPV/T hybrid system with beam splitter and fully tracked linear Fresnel reflector concentrator utilizing sloped panels. Sol Energy 2014;103:191–9.