Two side serpentine flow based photovoltaic-thermal-phase change materials (PVT-PCM) system: Energy, exergy and economic analysis

Accepted Manuscript Two side serpentine flow based photovoltaic-thermal-phase change materials (PVT-PCM) system: Energy, exergy and economic analysis

M.S. Hossain, A.K. Pandey, Jeyraj A/L Selvaraj, Nasrudin Abd Rahim, M.M. Islam, V.V. Tyagi PII:

S0960-1481(18)31303-X

DOI:

10.1016/j.renene.2018.10.097

Reference:

RENE 10747

To appear in:

Renewable Energy

Received Date:

07 May 2018

Accepted Date:

25 October 2018

Please cite this article as: M.S. Hossain, A.K. Pandey, Jeyraj A/L Selvaraj, Nasrudin Abd Rahim, M. M. Islam, V.V. Tyagi, Two side serpentine flow based photovoltaic-thermal-phase change materials (PVT-PCM) system: Energy, exergy and economic analysis, Renewable Energy (2018), doi: 10.1016/j.renene.2018.10.097

This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.

ACCEPTED MANUSCRIPT

1

Two side serpentine flow based photovoltaic-thermal-phase change materials

2

(PVT-PCM) system: Energy, exergy and economic analysis

3

M.S. Hossaina*, A K Pandeyb, Jeyraj A/L Selvaraja, Nasrudin Abd Rahima,c, M.M.Islama, V.V. Tyagid

4 5 6 7 8 9 10 11 12 13

Abstract Amalgamation of thermal collector at the back of PV overcomes with low energy conversion

14

efficiency issue upto some extent and improves overall efficiency of the systems. Use of phase

15

change materials (PCM) in PV/T collectors as an intermediate thermal storage media offers a

16

promising solution to this problem by storing large amount of heat. The aim of this research work

17

was to design and develop a photovoltaic/thermal-phase change materials (PV/T-PCM) system

18

and evaluate its energy, exergy and economic performance. Lauric acid as PCM contained in leak-

19

proof aluminum foil packets are placed around the flow channel allowing extended period of

20

thermal storage. The PV/T-PCM system has been studied at different volume flow rates viz. 0.5-

21

4 liter per minutes (LPM) to get the optimized performance of the system. Maximum thermal

22

efficiency of PV/T-PCM collector was found to be 87.72% at 2 LPM. Maximum electrical

23

efficiency of PV and PV/T-PCM systems has been found to be 9.88% and 11.08% (4LPM)

24

respectively. The maximum exergy efficiency of PV and PV/T-PCM system has been found 7.09%

25

and 12.19% (0.5 LPM) respectively. An economic analysis of the proposed system has also been

26

carried out with a view to examine the feasibility of its commercialization.

27 28 29 30 31 32 33

Keywords: Economic analysis, energy, exergy, phase change material, photovoltaic thermal, solar energy

a. b. c. d.

UM Power Energy Dedicated Advanced Centre, Wisma R&D, Level 4, Jalan Pantai Murni, University of Malaya, Kuala Lumpur 59990, Malaysia Research Centre for Nano-Materials and Energy Technology (RCNMET), School of Science and Technology, Sunway University, No. 5, Jalan Universiti, Bandar Sunway, Petaling Jaya, 47500 Selangor Darul Ehsan, Malaysia. Renewable Energy Research Group, King Abdulaziz University, Jeddah 21589, Saudi Arabia Department of Energy Management, Shri Mata Vaishno Devi University, Katra-182320, India.



Corresponding author: Email: [email protected] (A K Pandey), [email protected] (M.S. Hossain)

1

ACCEPTED MANUSCRIPT

34

Nomenclature A/F sinking fund factor A/P capital recovery factor AW annual worth Arc annual running cost A0, A collector area (m2) Ao ideal factor Ac area of pv collector (m2) BA annual benefit C heat capacity CA annual cost CF capacity factor Cafic change of aluminium foil insulation cover C thermal capacity (J/kg °C) N1, Nc number of glass covers Exin exergy in (W) Exout exergy out (W) Exloss exergy loss (W) Exd energy destruction (W)

F FF F G hw hconv hrad-1 & i Ic Ilc i I K n1

amount of money accumulate fill factor factor in collector top heat loss coefficient radiation intensity (W/m2) wind convection heat transfer coefficient (W/m2 K) convective heat transfer radiation losses initial cost installation cost interest rate current (A) global losses factor (W/m2 °C) day of year

35 36

1. Introduction

37

Two or more energy conversion devices or fuels can be can be combined to get the enhanced

38

efficiency which is typically known as hybrid power systems (Dursun, 2012; Jun et al., 2011).

39

Increase in photovoltaic (PV) module temperature deceases the electrical efficiency therefore,

40

cooling of PV module may increase the electrical efficiency. Cooling of PV can be done either

41

using air or water as a cooling fluid which is commonly known as photovoltaic/thermal (PV/T)

42

collector which produces electrical and thermal energy simultaneously (Hasanuzzaman et al.,

43

2016). The higher overall energy performance is important for the success of PV/T system

44

however, one of the advantage of the PV/T system is production of electrical and thermal energy

45

by the same system which reduce the demands on physical space and equipment cost as compared

46

to the separate PV and solar thermal systems which are placed side-by-side (Mohsen et al., 2009;

47

Sarhaddi et al., 2010). So far, many studies has been conducted by different authors around the

48

World on PV/T to improve the overall efficiency. A comparative study was performed on between

49

hybrid PV/T with active solar heating and cooling systems and passive convectional system,

50

overall thermal and electrical efficiency was found to be enhanced by nearly 25% in the proposed

51

model (Praveen kumar et al., 2017). Hybrid PV/T collector was also studied using simulation

52

model and it was found that electrical and thermal energies varied between −2.64% to +1.73% and 2

ACCEPTED MANUSCRIPT

53

−4.90% to +7.37% with experimental data. This can be considered as a reliable tool both for short-

54

term and long-term yield analysis (Simonetti et al., 2018).

55

There are several technologies, which can advantageously be applied to harness and harvest

56

more thermal energy from the PV/T collector, such as, nanomaterials, phase change materials

57

(PCM), etc. Out of which, the methods of latent heat energy storage is by using PCMs wherein the

58

material can store energy at a particular temperature by changing its phase. Enormous amount of

59

work on the PCMs is being carried out around the world to fulfil the demand on usage of solar

60

energy through more efficiently effective methods and systems (Abhat, 1983; Regin et al., 2008).

61

The PCM study was initiated in 1940 by Telkes and Raymond and research works on the holistic

62

entity were vigorously pursued further up to a certain turning, most probably due to the acute lack

63

of the associated sophisticated equipment of the period until it was significantly needed due to the

64

critical energy crisis in the late 1970s and early 1980s, and since then researches on the PCMs

65

have gained much interest, especially, in the solar energy applications, such as, solar heating

66

(Fuqiao et al., 2002; Lu et al., 2017; Telkes & Raymond, 1949). During this period many studies

67

had been carried out by the researchers recorded in the form of books and research papers to

68

galvanize further interests (Beckmann & Gill, 1984; Garg et al., 1985; Hossain et al., 2011;

69

Schmidt, 1981).

70

The exergy analysis can also be applied on the PV/T module with the phase change material

71

(PCM) in the hybrid (PV/T-PCM) system to evaluate both the energy and the exergy performances.

72

Michels and Pitz-Paal (2007) carried out a research on a cascaded thermal energy storage and a

73

signal stage thermal energy storage system and they found that the energy utilization efficiency

74

was higher than the traditional signal stage thermal energy storage system as confirmed by other

75

authors as well (Islam et al., 2016; Michels & Pitz-Paal, 2007; Pandey et al., 2018). Later on Tian

76

and Zhao (2013) investigated and compared those systems and the results showed that the cascaded

77

thermal energy storage not only gave a higher energy efficiency (up to 30%) but also achieved the

78

exergy efficiency (up to 23%) more than the signal stage thermal energy storage system (Tian &

79

Zhao, 2013). Robles et al. (2007) utilized water as a PCM where he made a bifacial PV module to

80

accordingly source the solar radiation long wavelength beams to create heat and transmit short

81

wavelength beams to the PV module to deliver power in which he found that the bifacial PV

82

module created around 40% more electrical energy than a conventional PV/T system (Robles-

83

Ocampo et al., 2007). (Yang et al., 2018) carried out the performance evaluation of PV/T-PCM 3

ACCEPTED MANUSCRIPT

84

and PV/T systems, where the primary energy-saving efficiency for the PV/T-PCM system

85

increased by 14% at irradiance of 800 W/m2 and water flow rate of 0.15 m3/h. Hammou and

86

Lacroix (2006) had proposed a hybrid thermal energy storage system using a PCM for improving

87

heat storage of the solar and electrical energies from the PV module in which they stored the solar

88

heat during sunny days and utilized it at night or during cloudy days. On the other experiment,

89

they obtained the smooth electrical energy during off-peak period and utilized it during the peak

90

periods. The results of their study showed that the electricity consumption for space heating is

91

reduced by 32% and more than 90% of the electricity consumed during the off-peak period

92

(Hammou & Lacroix, 2006; Tyagi et al., 2012). Hellstrom et al. (2003) investigated the impact of

93

optical and thermal performance of a flat-plate solar collector onto which they added a Teflon film

94

as a second glazing front into the PV panel from which the results showed that the overall

95

performance was increased by 5.6% at 50°C (Hellstrom et al., 2003). Martinopoulos et al. (2010)

96

utilized polycarbonate honeycombs to improve a heat transfer in solar collectors (Martinopoulos

97

et al., 2010). Metal foams (2009-2012) reviewed results showed high thermal conductivities and

98

large specific surface area which were confirmed by many researchers to have the abilities to

99

significantly enhance a heat transfer in phase change materials (PCMs). However, as far as the

100

authors are aware of, metal foams have not so far been examined nor experimented for their

101

potential capability to enhance heat transfer in recuperating tubes (Tian & Zhao, 2009, 2011, 2012;

102

Zhao et al., 2010).

103

The PCMs with a suitable adjustable temperature was chosen in the application because they

104

have high idle heat energy, high thermal energy conductivity and special heat energy which have

105

been found to be very suitable for a solar water heater (SWH) application and building sectors

106

(Agyenim et al., 2010; Kylili & Fokaides, 2016). The qualities supplied by the manufacturer may

107

change (Agarwal & Sarviya, 2016; Zalba et al., 2003). Hence, in the pre-design stage of the PCM,

108

it is suggested to use the right thermophysical properties of the PCMs which are for the most part

109

described by calorimetric examinations, like Differential Scanning Calorimeter (DSC), and

110

Differential Thermal Analysis (DTA) (Al-Hinti et al., 2010; Jamil et al., 2006). Generally, a few

111

relevant items can be connected to the machine to gauge the relevant heat properties (Kuznik et

112

al., 2011). Paraffin wax is the most suitable alternative because of its accessibility, non-

113

destructiveness, good liquefying temperatures, and a minimal operating effort (Al-Hinti et al.,

114

2010; Ho & Gao, 2009), hence the paraffin wax PCM (Sigma-Aldrich item no. 327212 (Sigma4

ACCEPTED MANUSCRIPT

115

Aldrich, 2013)) was chosen for this test. The liquefying temperature, enthalpy, and specified heat

116

energy were measured by a DSC instrument (Perkin Elmer Pyris calorimeter DSC4000). The DSC

117

was kept running from 30°C to 85°C at 5°C/min heating rate. The DSC test will be illustrating the

118

heating and cooling cycles of the PCM. In the DSC test results, the dissolving temperature of the

119

PCM was measured from the related onset temperature of the heating curve. In this exploratory

120

study, the dissolving temperature was found to be 56.06°C (Joulin et al., 2011).

121

It can be seen that none of the above authors done the energy, exergy and economic analysis of

122

two side serpentine flow based PVT-PCM system. The innovative configuration of the shapes and

123

arrangement of pipes are very important in a collector, in the sense that the pipe should be properly

124

heated for better thermal energy output. Thus, if the design is more effective, the output thermal

125

energy will increase. The parallel 2-side serpentine flow absorber collector and a modified pipe

126

arrangement were used throughout the plate collector in this study. The nonuse of PV/T collector

127

for thermal output in the absence of solar radiation is one of the major drawback of the PV/T

128

collector. Therefore, in the present study PCM has been incorporated in parallel 2-side serpentine

129

flow based PV/T collector to improve the overall performance of the system also to make the

130

system more reliable. The designed and developed PV/T-PCM was evaluated using energy and

131

exergy analysis. With a view to examine the feasibility of its commercialization, an economic

132

analysis of the proposed system has also been carried out. The maximum efficiency was found to

133

be improved and maximum thermal efficiency of PV/T-PCM collector was found to be 87.72% at

134

2 LPM. Maximum electrical efficiency of PV and PV/T-PCM systems has been found to be 9.88%

135

and 11.08% (4LPM) respectively.

136

2. Experimental setup

137

2.1 Design of PV/T system

138

The detailed design of a thermal collector is as shown in Figure 1. A 7.62 cm to 10.16 cm air

139

gap has been kept between each pipe and a 17.78 cm gap between the parallel two sides of the

140

absorber. The inner side air gap is important as when the sunlight strikes the PV module glass

141

plate, the internal air is heated like the inside of a greenhouse. Nevertheless, water flowing inside

142

the copper pipe takes time due to frictional pressure drop to reach the outlet and during this time,

143

water flowing inside the absorber tubes is heated because of the hot water from the collector outlet.

5

ACCEPTED MANUSCRIPT

144 145

Figure 1: PV module and layout of PV/T thermal collector

146 147

2.2 PCM Thermal Control

148

In the present research, five different PCM materials are tested with DSC, from which lauric

149

acid is selected based on experimental requirement. Table 1 shows the melting temperature range

150

of the five PCMs. Their respective DSC test results are given in table 1 as well. Table 1: Properties of PCM materials

151

Name of PCM

Melting temperature range (ºC)

Paraffin 1-tetradecanol Lauric acid Decanoic acid synthesis Decanoic acid natural

52-54 36-40 44-46 27-32 29-33

152

6

Actual temperature range (ºC) On Peak End set set 44.70 52.06 54.40 36.39 38.23 41.28 42.84 43.72 45.76 30.65 33.01 35.39 30.24 32.06 34.97

Heat of fusion (kJ/kg) 167.27 259.44 228.90 179.13 178.98

ACCEPTED MANUSCRIPT

153

2.3 Design of PCM Blocks

154

Phase change materials (PCM) include the use of lauric acid which is a powder like compound

155

at room temperature. There are several techniques used to let the PCM to manage its thermal

156

transfer, e.g., in glass container, in pouch, in separate metal box, etc. However, in the present

157

research, aluminum foil packets have been used in the PCM that is not only light in weight, but it

158

also performs efficient heat transfer. Each packet was 38.5 inches in length and 8 inches in breadth;

159

hence, eight such packets were required to cover the 39 in. × 65.5 in. PV module rear surface. The

160

PCM containing aluminum packets are placed in close thermal contact with the copper flow

161

channel and secured to the PV frame by means of another aluminum sheet. Figure 2 show the

162

detailed arrangement of the PCM packets on the PV panel rear side.

163

164

Figure 2: 3D view of flow channel and PCM packets

165 166

2.4 Fabrication of PV/T-PCM System

167

The PV/T collector comprises of two basic components, viz., a PV as an electrical component

168

and a thermal collector as a heat exchanger. The PV module selected for the fabrication of the

169

PV/T unit is a 250-W 60-cell p-Si module. The detailed specification of the module is given in

170

Table 2.

171 172 7

ACCEPTED MANUSCRIPT

173

Table 2: Specification of PV module EPV (ENDSUPV industries) Model Short Circuit Current (Isc) [A] Open Circuit Voltage (Voc) [V] Maximum Power (Pmax) [W] Current at Pmax [A] Voltage at Pmax [V]

EC61215 (2nd edition) 8.926 38.194 257.597 8.416 30.606

*The electrical characteristics are within 0-3% of the indicated values under Standard Test Conditions. (1000W/m2, 25 °C. AM 1.5) 174 175

Copper pipes are used because of their high thermal conductivity. The dimensions of the pipes

176

are 1.27 cm in diameter, 1 mm thick and 1475.74 cm long. The copper pipe is attached to an

177

aluminum absorber sheet by means of a thermal conductive paste. The specifications of the

178

conductive paste are as shown in Table 3.

179

Table 3: Specifications thermal conductive paste (lazada.com.my, 2017) Thermal Conductivity Thermal Resistance Specific Gravity Operating temperature Composition: Silicone Compound Carbon Compound Zinc Oxide Compound

0.925W/m-k 0.262ºC-in2/W 2.0g/cm3 at 77ºF (25ºC) -30ºC ~ 300ºC 50% 20% 30%

180 181

The PCM packet which is made of aluminum sheet of 0.5 mm thick. The PCM packet is coated

182

with a high thermal conductivity non-sticky paper. Hence, each dimension of the packet is 1.27

183

cm in thickness, 21.59 cm width, and 83.82 cm long. This is a unique idea to use PCM at the rear

184

side of the PV panel. The complete assembly of the PV/T-PCM system is as shown in Error!

185

Reference source not found.3.

8

ACCEPTED MANUSCRIPT

186

Figure 3: Complete PV/T-PCM system along with reference PV

187 188

2.5 Installation and Instrumentation of the Experimental Set-up

189

After the design and fabrication stages have been completed, the sub-systems, i.e., PV/T and

190

PCM systems are assembled together to form the complete PV/T-PCM module system and

191

installed in the UMPEDAC Solar Garden at Level–3, Wisma R&D, University of Malaya. The

192

slope of the PV/T panel (β) is determined by Cooper’s equation (Hossain, 2013; Struckmann,

193

2008). The slope of the collector is calculated from the equation:

194

 = 23.45 sin[0.9863 (284 + n1 )]

(1)

195

 = (Q1 -  )

(2)

196

where, δ is the angle of inclination and n1 is the numerical day of the year and β is the orientation

197

of the surface is towards the equator. The slope of the test modules in the present study were kept

198

at 15°.

199

In the present study, data for different parameters, such as, inlet and outlet water temperatures,

200

PV panel top and rear temperature, ambient temperature, water flow rate and solar radiation have

201

been measured. For this purpose, instrumentations that were used for measuring different 9

ACCEPTED MANUSCRIPT

202

parameters and collection of experimental data. These include thermocouples (K-type),

203

pyranometer, I-V tracer, data logger (series 3), and a computer for data acquisition can be observed

204

in Figure 3. Table 4 shows, the range of capacities and the accuracy of the experimental observing

205

equipment. Before for experimental study, all the measuring instruments have been properly

206

calibrated against standard apparatus. Table 4: Ranges of the measuring instruments

207

Instrument Data logger (series 3) Pyranometer (silicon) Flow meter I-V tracer Thermocouple (type K) 208

Range Accuracy -270 to 1372°C ±2% -2 0-2000 W/m ±5% 0.5-4 LPM ±0.5 0 to 50V & 0 to 16A ±5% -200 to 1000°C ±0.5

3. Analysis

209

In this work, experimental data have been collected based on the requirements for calculating

210

the thermal, electrical energy and exergy performances. The experimental data have been gathered

211

in three different methods. Firstly, a reference solar PV module (60 cell-Polycrystalline, 250W)

212

and PV/T-PCM only system was arranged and studied simultaneously under the same outdoor

213

condition. The data had been collected with different water flow rates ranging from 0.5 to 4 LPM

214

(litre/min).

215

3.1 Energy Analysis

216

The thermal efficiency (ηth) of the conventional flat plate solar collector is calculated using the

217

following formulae as shown below (Hossain et al., 2015) (Ibrahim et al., 2014b; Park et al., 2014): .

Qu  AG

218

 th

219

where Qu is heat loss, A is area of collector and G is solar radiation.

220

Under these conditions, the useful collected heat (Qu) is given by:

221

   Qu  m C p (TOut  TIn )  m PCM  LPCM   

222 223 224

where m is mass of water flow rate, Cp is temperature gradient between the thermal factor temperature at the collector exit and the point of entry, TOut is outlet water temperature and TIn is inlet water temperature.

(3)

(4)

.

10

ACCEPTED MANUSCRIPT

The phase change material (PCM) mass (mPCM) can be calculated as follows (El Khadraoui et

225 226

al., 2016; Shukla et al., 2009):

227

m PCM 

Qch m

f

i

m

(5)

LF   C p.s (T )dT   C p.l (T )dT 228 229 230

where Cp,s, Cp,l are specific heat of solid and liquid phase of the PCM, respectively. LF is latent heat of PCM, Qch is heat charging phase, i, m and f are initial, melting and final temperature of PCM, dT is the temperature rise.

231 232

A solar cell’s energy conversion efficiency is the percentage of power converted and collected equation (6).

233

 el 

234

(6)

235

The solar energy absorbed by the PV modules is converted into electric energy and thermal energy,

236

but the thermal energy is dissipated by convection, condition and radiation.

237

3.2 Exergy Analysis

Pmac AG

238

In the following formulae, Exout is the maximum amount of exergy that can be obtained from a

239

system whose supplying energy is Exin: the energy consumed is equal to the exergy loss Exloss, as

240

in equation (7) (Sudhakar & Srivastava, 2014).

241

E x in  E x out  E x loss

242

(7)

The exergy efficiency of the PV module can be expressed as the ratio of the total output and

243

total input exergy as shown in equation (8) (Sudhakar & Srivastava, 2014).

244

 ex 

245 246 247 248 249

E xoutput

(8)

E xinput

Equation (9) shows the inlet exergy of a PV system which includes the only solar radiation intercity exergy. E xin

 4 T  A  G  1   a  3  Ts

 1  Ta     3  Ts

  

4

  

(9)

The exergy output includes the thermal exergy and the electrical exergy of the PV system.

E xout  E xthermal  E xelectrical

(10) 11

ACCEPTED MANUSCRIPT

250

The thermal exergy can be expressed as in equation (11):

251

 T  E xthermal  Q 1  a   Tc 

252

where, Q is heat loss, Ta is ambient temperature and Tc is the PV cell temperature

253

The overall heat loss coefficient is U.

254

Q  UA(Tc  Ta )

255

where, A is collector area

256

(11)

(12)

The overall heat loss coefficient of a PV module includes the convection and the radiation losses

257

U  hconv  hrad

258

The convective heat transfer coefficient can be written as follows:

259

hconv  2.8  3.v

260

where, v is the wind speed.

261

(13)

(14)

Radiative heat transfer coefficient between PV array and surroundings can be writing in two

262

equations (15) and (16) (Ibrahim et al., 2014a):

263

hrad 1   (Tsky  Tc )(T 2 sky  T 2 c )

(15)

264

hrad 2  1.78 (Tm  Ta )

(16)

265

Effective temperature of the sky

266

Tsky  Ta  6

267

(17)

The solar cell temperature can be calculated using equations (15), (16) and (17) (Nahar et al.,

268

2017; Rahman et al., 2017):

269

Tc 

270

where, Psg is packing factor of the solar module and Tb is the rear panel temperature.

271

Psg G ( g    el )  (hconvTa  hrad  2Tb )

(18)

hconv  hrad  2

The exergy inflow of the collector surface is given by equation (19) (Hazami et al., 2016;

272

Ibrahim et al., 2014b):

273

E

274

 T  273   E xth  Qu 1  a  To  273 

in

  ( E xth  E x pv )   E xd

(19)

(20) 12

ACCEPTED MANUSCRIPT

E x pv 275

 4T   pv  A  N c  G  1   a  3  Ts

 1  Ta     3  Ts

  

4

  

(21)

276

E xPVT  E xth  E x pv

277

where,

278

Exin is input exergy same as equation, Exout is output exergy, Exth is thermal exergy, EXPVT is

279

photovoltaic thermal exergy, A is collector area, Nc is number or quantity of collectors, Ts is sun

280

temperature, Exd is the energy destruction

281

 ex  1 

282

where, ηex is the exergy efficiency

283

(22)

E xd

(23)

E xin

The analytical parameters of the solar PV and PV/T-PCM systems are as presented in Table 5. Table 5: PV and PV/T-PCM system characteristics

284

Description Collector area Number of glass cover Emittance of glass Emittance of plate Collector tilt Specific heat of working fluid Sun temperature Wind velocity Transmittance Absorptance Packing factor of the solar module

Symbol A, Ac N1, Nc

g p 

Cp

s   

Psg i m f LF

Initial temperature Melting temperature Final temperature Latent heat 285 286

Value 1.64 1 0.88 0.95 15 4185.5 5777 1.1 0.96 0.90 0.8

Unit m2

42.48 43.72 45.76 228.9

°C °C °C KJ/kg

J/kg °C °C m/s

3.3 Economic Analysis

287

Annual worth (A.W) is the difference between an annual benefit (revenue) and annual cost

288

(Kumar & Tiwari, 2009; Leland T & Anthony J, 1998). It is a gain if it is a net benefit, and a loss

289

if it is a net loss, i.e.

290

A.W  B A  C A

(24) 13

ACCEPTED MANUSCRIPT

291

where, BA is the annual benefit and CA is the annual cost.

292

A cash flow formula (25) has been utilized for the solar collector systems related economic

293

analysis (Hossain et al., 2015):

A.W) PV = - (I c + I lc ) (A/P, i, N) - A rc - (C afic ) (A/F, i, N) 294

Solar

(25)

295

where,

296 297

Ic is initial cost, Ilc is installation cost, A/P is capital recovery factor, i is interest rate, N is life span, Arc is annual running cost and Cafic is change of aluminum foil insulation cover.

298 299 300

To use the formula of equations (26) & (27), any lump-sum payments or benefits must be converted into equivalent uniform periodic time by using of the capital recovery factors (A/P, i, N) and (A/F, i, N).

A/ P  301

A/ F  302 303

i (1  i ) N (1  i ) N  1

(26)

i (1  i ) N  1

(27)

3.4 Market survey

304

A solar energy system is generally defined by a high initial cost and low operational costs as

305

compared with the relatively low initial cost and high operating costs of Electric Water Heater

306

system. Heating water through solar energy also means long-term benefits, such as, free from

307

future fuel shortages and the maintenance of environmental benefits. The cost benefit analysis is

308

performed based on the Annual worth method which deals with two parts, namely, one is the solar

309

water heater cost whereas the other is the electric water heater cost and their comparisons. The

310

cost analysis is presented in a cash flow diagram.

311

The following Table 6, 7 and 8 is obtained from a survey performed in the Malaysian market.

312

This experiment on the flat plate PV/T hybrid collector. The total cost of constructing a solar PV

313

module at MYR 2000 (US$ 469.21) per unit, solar thermal collector system at MYR 1650.77 (US$

314

387.33) per piece.

315

Table 6: The breakdown cost of solar PV module Component Solar PV module cost

Description 60 cells-Poly 250W 14

Retail price (MYR) 2000

ACCEPTED MANUSCRIPT

Installation cost Salvage Value Total Retail Cost

100 0 2200 (US$ 515.81)

316

Table 7: The breakdown cost of thermal collector

317

Component Thermal collector

Description Absorber Aluminium sheet (1mm, 39, 58 inch) Absorber Copper Pipe (1mm, 0.5 inch, 581 inch) Copper Pipes elbow connector (0.5 inch dia, 68 pieces) Pipe to absorber sheet gaps fill up with heat conducting paste Aliminium foil cover Insulation sheet Ceramic Fiber paper Plywood sheet 6mm Plywood (2.5, 3 fit) Back cover sheet Aliminium 1mm sheet Inlet, Outlet pipe 6 meter palate 0.5m dia Gate valves Mattel and plastic Storage tank 80 gallon plastic tank Water Flow meter 0.5 to 4 water LPM Other Pudding, Screw, Rods, Silicone paste etc. Installation Cost Salvage Value Total Retail Cost

Retail price (MYR) 36 280.77 578 30 30 50 30 36 20 30 180 250 200 100 0 1750.77 (US$ 410.48)

318 319

Table 8: The breakdown cost of PCM

320

Component PCM Aluminum packets for PCM Installation Cost Salvage Value Total Retail Cost

Description Phase change material (Lauric acid, 8.72kg)

Retail price (MYR)

7 packets

40 100 0 1853.76 (US$ 43153)

321

15

1813.76

ACCEPTED MANUSCRIPT

322

4. Results and discussion

323

A PV/T-PCM water collector with an innovative serpentine flow channel has been designed

324

and fabricated and its performance has been studied as a PV/T-PCM system. The outcomes of the

325

present research work and the corresponding explanations of the results wherever necessary. Upon

326

design, fabrication and installation of the system, data for different parameters, like PV top surface,

327

back surface, inlet water and outlet temperatures were collected at flow rates ranging from 0.5 to

328

4 liters per minute (LPM). The detail results can be seen in Appendix A and B. An overall

329

comparative study among all the systems while an economic analysis has been given in section

330

4.4 and 4.5.

331

4.1 Hourly Variation of PV and PV/T-PCM Different Parameters

332

Comparative performance investigation of the reference PV and PV/T-PCM systems. Hourly

333

variation of different parameters obtained with the mass flow rate were measured 0.5, 1, 2, 3 and

334

4 LPM are shown in Appendix A in Figure A.1, A.2, A.3, A.4 and A.5 respectively. From each of

335

the figures, it can be seen that cell temperature of PV/T-PCM module is always lower than that of

336

the PV/T only module for all the flow rates, establishing the justification of using PCM in thermal

337

management of the PV/T system.

338

In Table 9 is given the details of various measured and calculated parameters for a mass flow

339

rate of 4 LPM. It can be seen that power output (Pmax) increases with the irradiation level and

340

reaches to its maximum (995 W/m2) at 13:00 pm.

341

Table 9: The measured parameters at mass flow rate of 4 LPM Time Ta (°C) Tin (°C) To (°C) Pmax (W) G (W/m2) 10:00

31.85

22.76

23.94

79.67

375

10:30

32.31

21.60

22.61

69.01

358

11:00

32.11

24.11

26.68

146.61

777

11:30

31.94

26.60

28.81

139.16

858

12:00

34.46

28.04

30.73

132.66

880

12:30

34.83

28.65

31.93

140.28

916

13:00

35.36

28.83

32.82

160.29

995

13:30

36.79

29.18

32.78

142.27

957

16

ACCEPTED MANUSCRIPT

14:00

34.63

29.85

32.39

142.03

732

14:30

34.21

29.43

31.72

140.47

707

15:00

35.11

29.74

32.13

114.03

665

15:30

34.56

29.89

31.18

102.00

448

16:00

33.79

27.58

27.82

73.54

336

342 343

Figure 4 shows an average inlet, outlet and cell temperature differences based on mass flow

344

rate of water. PV and PV/T-PCM cell temperature performance, which is affected on solar

345

radiation and ambient temperature. But because of PCM and mass flow of water the PV/T-PCM

346

cell temperature drops significantly. The maximum cell temperature difference between PV and

347

PV/T-PCM panels are 10.09°C, 10.26°C, 13.15°C, 12:45°C and 10.57°C respectively. Whereas

348

the maximum rise in PV/T-PCM collector outlet water temperatures are 26.40°C, 15.73°C, 8.66°C,

349

5.22°C are 3.98°C respectively.

Temperature (°C)

70 60 50 40 30 20

Ta

Tout-Tin

Tcell (PV)

Tcell (PV/T-PCM)

10 0 0.5

353

2

3

4

Mass flow rate (LPM)

350 351 352

1

Figure 4: Average inlet outlet water and cell temperature different PV and PV/T-PCM parameters (0.5 to 4 LPM) 4.2 Energy Analyses

354

The energy analysis that is based on the first law of thermodynamics presents a rough picture

355

that shows how the input energy has been exploited and which sectors are the prime contributors

356

in the energy consumption. In the present study, the change in different energy parameters, such 17

ACCEPTED MANUSCRIPT

357

as, electrical power output, electrical efficiency, thermal efficiency, etc., have been analyzed as a

358

function of the solar irradiation, cell temperature and water flow rate in order to observe which of

359

them has the prominent effect on the energy performance of the PV/T-PCM systems. Phase change

360

materials (PCM) are substances that possess high heat of fusion. These materials can store (or

361

release) huge amount of energy as latent heat during their freezing (or melting) process, the heat

362

being taken from the surrounding environment. When the surrounding temperature of a solid PCM

363

reaches its melting point, it starts to absorb heat from the ambient, gets molten and stores this

364

energy as latent heat as long as the surrounding temperature is above its melting point. On the

365

other hand, when again the surrounding temperature falls and come near the freezing point, PCMs

366

release the stored energy and gets solidified. It may be mentioned here that an experimental study

367

on PV/T-PCM has been carried out for five different flow rates of cooling water, however,

368

representative results of an optimum flow rate have only been presented in the forthcoming

369

sections.

370

4.2.1 Effect of Irradiation and cell temperature on Electrical Performance

371

The effect of increased irradiation and cell temperature level on electrical power and electrical

372

efficiency has been illustrated in Appendix B. The results shows that the effect of increased

373

irradiation and cell temperature level on electrical power and electrical efficiency at the mass flow

374

rate of 0.5 LPM. The peak solar radiation is 999 W/m2, the electrical power of the PV and PV/T-

375

PCM module is 140.64 W and 151.26 W respectively as shown in Figure B.1. The maximum

376

difference between the output power of PV and PV/T-PCM is 18.28 W at 10:45 AM. The

377

maximum difference between electrical efficiency of PV and PV/T-PCM module is 2.14% at 10:45

378

AM. The maximum electrical efficiency of the PV/T-PCM is 13.92% at 10:15 AM. The

379

experimental investigation has been carried out on-site under real ambient conditions, wherein the

380

radiation intensity at any time may go down due to shading from cloud, etc. The data acquisition

381

is a continuous process in which some irregular data may also be saved. These irregular data do

382

not show the trend.

383

Figure A.1 and Figure B.1 shows that solar radiation reaches its peak of 999 W/m2, the ambient

384

temperature to 36.52°C and the maximum cell temperature difference to 4.71°C. PV/T-PCM

385

output power is observed to increase by 10.09 W at 2:15 PM. As can be seen power difference

386

between PV and PV/T-PCM because of the effect of cell temperature (as explained above). At low 18

ACCEPTED MANUSCRIPT

387

mass flow rate (0.5 LPM), cell temperature is dropped very little for PV/T-PCM system. As a

388

result, PV/T-PCM system produce little amount of power. The variation in the PV and PV/T-PCM

389

efficiency is from 0.40% to 2.14%. On the other hand, cell temperature variation is 4.16°C to

390

5.81°C for PV and PV/T-PCM, respectively.

391

Figure B.2 shows the effect of irradiation level on electrical power and electrical efficiency at

392

mass flow rate of 1 LPM. The highest solar radiation attained is 988 W/m2, at which the electrical

393

power of the PV and PV/T-PCM module is 138.40 W and 145.45 W respectively. The maximum

394

difference between the output power of PV and PV/T-PCM is 24.97 W at 2:15 PM. From Figure

395

B.2 it can be observed that the maximum electrical efficiency of the PV/T-PCM is 14.25% at 3:45

396

PM. Also, the maximum electrical efficiency difference between PV and PV/T-PCM module is

397

1.55% at 2:15 AM. The irradiation level increases rapidly at the early part of the day, while during

398

midday the variation becomes minute. That is why, the electrical power and efficiency remain

399

almost same near an average value.

400

Under the peak solar radiation of 988 W/m2 at 1:30 PM the ambient temperature is 36.34°C and

401

cell temperature difference is 7.03°C, whereas the increase in PV/T-PCM power output is 7.05 W,

402

respectively as shown in Figure A.2 and Figure B.2. When the mass flow rate is increased from

403

0.5 to 1.0 LPM, cell temperature for PV/T-PCM system is lower as compared to that at 0.5 LPM.

404

After that the cell temperature is observed to up and down and the power reached at maximum

405

level 24.97 W. It is also observed that around 1:45 to 2:45 PM, the solar radiation was high.

406

Because of PCM, the cell temperature is dropped suddenly and it maintains a little time then again

407

back to its original trend. The variation in the PV and PV/T-PCM is from 0.05% to 1.55%, while

408

the cell temperature variation 5.08°C to 6.40°C respectively.

409

Figure B.3 presents the electrical power and electrical efficiency of PV/T-PCM systems at a

410

mass flow rate of 2 LPM. The electrical power of the PV and PV/T-PCM module are 133.39 W

411

and 150.06 W respectively under the peak radiation of 983 W/m2. The maximum electrical

412

efficiency of the PV/T-PCM is 13.04% at 10:15 AM. In addition, the maximum electrical

413

efficiency difference between PV and PV/T-PCM module is 2.33% at 3:15 PM.

414

The ambient temperature is 35.21°C, and cell temperature difference is 5.64°C and the increase

415

in PV/T-PCM is 16.67 W under the peak radiation of 983 W/m2 at 12:00 noon as shown in Figure 19

ACCEPTED MANUSCRIPT

416

A.3 and Figure B.3. As the mass flow rate increases from 1 to 2 LPM, the cell temperature of

417

PV/T-PCM collector drops are high and output power increases as compared mass flow rate of 0.5

418

and 1 LPM respectively. Because of increasing mass flow rate with PCM cooling capacity. It is

419

observed, PV/T-PCM maximum power found 21.71 W at cell temperature of 7.98°C. Figure B.3

420

also reveals that the variation in the PV and PV/T-PCM is from 0.18% to 2.33%, while the cell

421

temperature variations are 13.15°C to 9.33°C respectively.

422

Electrical power and efficiencies at mass flow rate of 3 LPM are shown in Figure B.4. At the

423

peak solar radiation of 989 W/m2, the electrical power of the PV and PV/T-PCM module are

424

116.62 W and 130.76 W respectively. The maximum output power for PV/T-PCM module is

425

140.70 W at 3:00 PM. On the other hand, the maximum electrical efficiency of PV/T-PCM system

426

is 13.90% at 10:30 AM. Furthermore, from Figure B.4 is seen that the maximum electrical

427

efficiency difference between PV and PV/T-PCM module is 1.74% at 12:00 PM.

428

For PV/T-PCM system, the ambient temperature is 37.26°C, cell temperature difference is

429

6.53°C and the increases in output power is 14.13 W at peak radiation of 989 W/m2 at 1:45 PM as

430

shown in Figure A.4 and Figure B.4. As the mass flow rate increases from 2 to 3 LPM, the cell

431

temperature of PV/T-PCM drop is little as compared that of 2 LPM. The maximum power is found

432

25.10 W at cell temperature of 3.93°C. Furthermore, the variation in the PV and PV/T-PCM is

433

from 0.45% to 1.74%, while the cell temperature variation 4.06°C to 5.06°C respectively.

434

The effect of increased irradiation level on electrical power and electrical efficiency has been

435

illustrated in Figure B.5 at optimum mass flow rate of 4 LPM. It can be seen from Figure B.5 that

436

electrical power and efficiency of PV/T-PCM systems increases with increasing irradiation level.

437

In both cases, it surpasses the power output of the reference PV system over the full range of

438

irradiation as can be seen from Figure B.5. Firstly, the effect of cooling becomes effective at higher

439

irradiations that is portrayed by the expanding gap between the trend lines of PV and PV/T-PCM

440

systems. The temperature difference between the inlet water and outlet water is very trivial at lower

441

radiation level. As the irradiation level increases, the temperature difference increases to mobilize

442

the rate of heat transfer, which helps to remove more heat from the higher irradiations. This

443

tendency is slightly greater in the case of the PV/T-PCM system, evidently indicating the practical

444

usage of the PCM in temperature control.

20

ACCEPTED MANUSCRIPT

445

Secondly, the increment rate of power output is steeper in the range of around 300 to 1000

446

W/m2, after which the effect of increased irradiation own diminished. Hence, it may be concluded

447

that the highest output from a PV/T or PV/T-PCM panel in typical Malaysian weather condition

448

can be obtained under irradiation of around 1000 W/m2. Thirdly, at 992 W/m2, the electrical power

449

of the PV and PV/T-PCM module is 123.85 W and 160.29 W respectively, which is cleared

450

enhancement in the power output with the PCM and mass flow rate used for thermal control.

451

Results show that power levels of solar cell vary under different levels of illuminations. The panel

452

current increases in proportional to solar radiation with little increases in panel voltage. Similarly,

453

panel power increases in proportion to solar radiation level. The difference between maximum

454

output power of PV and PV/T-PCM is 36.44 W at 1:00 PM. For every 100 W/m2 increase in

455

irradiation level, output power rose by 13.12 W for PV/T-PCM respectively. Phase change

456

materials possess a good ability of storing large amount of heat, which helps to lower the cell

457

temperature and keeps as near as possible to the STC value, thereby improving the electrical

458

output. Figure B.5 show the response of electrical efficiency as a function of the irradiation of

459

PV/T-PCM systems respectively both on the performance of the same reference PV module. It is

460

evident from the Figure B.5 that the efficiency of all types of photovoltaic devices, PV and PV/T-

461

PCM, increases up to an irradiation level of around 300 to 600 W/m2, which then drops

462

significantly with increased irradiation. Therefore, photovoltaic devices perform best under the

463

above-mentioned range of irradiation in Malaysian condition. While the proposed PV/T-PCM

464

system show better electrical efficiency than the reference PV module. As the irradiation level

465

increases from 375 to 992 W/m2, electrical efficiency drops from 12.88% to 9.78% for PV/T-PCM

466

module and 12.41% to 7.56% for PV module. The maximum difference between PV and PV/T-

467

PCM system is 2.48% at 11:15 AM. It may be noticed from and that maximum electrical efficiency

468

of the PV/T-PCM is 14.42% at 3:15 PM, which evidently shows distinctive improvement in the

469

electrical performance by employing PCM. For PV/T-PCM modules every 100 W/m2 increase in

470

irradiation level, electrical efficiency drops by 0.55% respectively. This holds good not only for

471

the maximum point, but also for almost the entire range of efficiency, which further establishes

472

the appropriate choice of employing the PCM thermal control in the PV/T systems.

473

The adverse effect of increased cell temperature in electrical power output of the PV/T-PCM

474

systems is apparently conceivable from Figure B.5 in which it is readily observed that the

475

corresponding power drop in the PV/T-PCM system is greater than that of the PV system for 21

ACCEPTED MANUSCRIPT

476

almost the same temperature rise. The reason behind the alternation in power level is that panel

477

temperature leads to a little increase in panel current while it decrease the panel voltage

478

proportionally. Panel power decrease since the voltage decrease rate is more than the increase in

479

current rate. On the other hand, increase in module temperature reduce the band gap of a solar cell,

480

whereby effecting the solar cell output parameters. Open circuit voltage the most affected

481

parameter due to increase in temperature. Figure A.5 and B.5 shows the tendency for PV/T-PCM

482

and PV reference. At 992 W/m2, the ambient temperature was 35.36°C and the cell temperature

483

difference were 3.33°C and the output power difference was 36.44 W at 1:00 PM. The cell

484

temperature and output power vary because of mass flow rates and PCM cooling capacity. For

485

every 1°C decrease in cell temperature, output power increases by 8.76 W for PV/T-PCM systems

486

respectively.

487

Drop in the electrical efficiency due to the cell temperature rise is less prominent in photovoltaic

488

thermal systems, especially in the case of a PV/T-PCM system. This is due to the fact that PCMs

489

can exert a better control over the cell temperature rise by its intrinsic ability in absorbing a large

490

amount of heat through alternate melt/freeze cycles at a particular range of temperature. It may be

491

perceived from Figure B.5 that the variation in the PV and PV/T-PCM is from 0.48% to 2.48%

492

respectively. In addition, electrical efficiency of the PV/T-PCM is higher than the PV efficiency

493

demonstrating the favorable effect of cooling. During afternoon, PV/T-PCM system works with

494

efficiencies as high as 13.82% or more. For every 1°C decrease in cell temperature, efficiency

495

increases by 0.37% for PV/T-PCM systems respectively. Another notable point from these figures

496

19-23 is that for both the power output and the efficiency curves, the gap between the PV and the

497

PV/T-PCM trend lines is wider. This portrays a better relative improvement in both the electrical

498

power and the efficiency of the PV/T-PCM system than that of the PV module. This finding also

499

confirms that the PV/T-PCM system has a superior performance.

500

Figure 5 shows an average PV and PV/T-PCM electrical efficiency and power differences based

501

on mass flow rate of water. PV/T-PCM module electrical efficiency and output power increases

502

because of mass flow rates and PCM cooling capacity.

22

25

250

20

200

15

150

10

100

5

PV (%)

PV/T (%)

PV (W)

PV/T-PCM (W)

0 1

2

3

4

Mass flow rate (LPM)

503

506

50

0 0.5

504 505

Electrical power (W)

Electrical efficiency (%)

ACCEPTED MANUSCRIPT

Figure 5: Average electrical power and efficiency different PV and PV/T-PCM parameters (0.5 to 4 LPM) 4.2.2

Effect of Water Flow rate on Thermal Performance

507

Photovoltaic thermal (PV/T) collectors, as the name implies, are meant for thermal output along

508

with electricity. Moreover, there is a material limit for silicon cells, especially, in terms of life

509

span, after which the electrical performance cannot be improved. On the other hand, there are wide

510

provisions for improvement in the thermal performance by adopting effective thermal energy

511

harvesting techniques. For this particular reason, the thermal performance of PV/T-PCM collectors

512

is of great importance which needs to be investigated thoroughly. Thermodynamic performance

513

of any system can be analyzed from two different viewpoints, i.e., one is based on the first law of

514

thermodynamics while the other is its second law. Energy analysis of PV/T-PCM systems only

515

based on the first law of thermodynamics has been discussed in this section and second law-based

516

analysis, i.e., exergy analysis which is elaborated in the following section. In both cases, variation

517

in performance parameters have been presented as a function of the mass flow rate of heat transfer

518

fluid (HTF), namely, water.

519

Thermal performances of PV/T-PCM systems have been illustrated in Figure 6 (a), respectively

520

wherein the performance has been portrayed in terms of heat gain, thermal efficiency and outlet

521

water temperature. Although PV/T-PCM collectors are meant for both electricity and heat

522

productions, one of the major applications of these devices are in warm water supply. Hence, 23

ACCEPTED MANUSCRIPT

523

together with heat gain and thermal efficiency of the device, the level of outlet water temperature

524

has been used here as an index for the thermal performance.

525

Figure 6 (a) present the heat gain as well as the thermal efficiency of PV/T-PCM modules,

526

respectively. It can be noticed that both the heat gain and the thermal efficiency follows the trend

527

of a bell-shaped curve although the distribution of the values are not the same nor symmetrical.

528

This trend signifies the fact that there is an optimum flow rate at which the peak performance is

529

obtained. For the PV/T-PCM modules provide as high as 1024.01 W with a thermal efficiency of

530

87.71% at 2 LPM. Hence, the use of PCM can conveniently provide 164.09 W more heat gain

531

capacity. Figure 6 (b) show the outlet water temperature along with the inlet water temperature produced

533

by the PV/T-PCM systems, respectively. It is obvious that the outlet water temperature decreases

534

gradually with increasing water flow rate which is evident from both figures 6 (a) and 6 (b). Hence,

535

in order to get warm water supply with better thermal efficiency, the flow rate should be

536

maintained between 1 to 2 LPM. Another revealing fact from Figure 6 (b) is that the PV/T-PCM

537

system provides relatively lower outlet water temperature, which is due to the system's huge

538

thermal storage capacity. However, the major benefit of PCM thermal storage is in its extended

539

period of availability of heat which makes the PV/T-PCM modules highly favorable for night time

540

thermal energy supply. 100

1050

90

1000

80

950

70

900

60

850

50

800

40

750

30

700

Thermal Effi (PV/T-PCM) Heat gain (PV/T-PCM)

20

650

10

600 0.5

541 542 543

1

2

(a)

24

3

4

Heat gain (W)

Thermal efficiency (%)

532

Water inlet & outlet temperature (°C)

ACCEPTED MANUSCRIPT

45 40 35 30 25 20

Tin

15

To

10 5

PV/T-PCM

0

0.5

1

2

3

4

Water flow (LPM)

544 545

(b)

546 547

Figure 6: Effect of water flow rate on thermal performance of PV/T-PCM collector (a): Thermal efficiency and heat gain (b): Inlet and outlet temperatures

548

4.3

Exergy Analysis of PV/T-PCM Systems

549

The limitation of the first law of thermodynamics analysis is that it does not account for the

550

energy quality, rather all forms of energies, viz., electric, mechanical, chemical, thermal energy,

551

all of which have values leading to a wrong assessment. The second law of thermodynamics comes

552

to help in this context introducing the concept of exergy which is the thermodynamic property of

553

combined energy quantity and quality to portray the real picture of the energy utilization

554

efficiency. Exergy is the maximum useful work obtainable from a system during a process when

555

the system is brought to an equilibrium with a heat reservoir (Perrot, 1998). In other words, exergy

556

is defined as the maximum amount of work that can be produced from a flow of mass or energy

557

as it comes into an equilibrium with a reference environment (Yazdanpanahi et al., 2015a).

558

Therefore, the exergy performance of the PV/T-PCM systems have been evaluated in this section

559

to gauge their actual working efficiency.

560

Figure 7 show the exergy output and exergy efficiency of the PV/T-PCM systems, respectively.

561

It may be noticed from the figure 7 that exergy output becomes almost constant after a certain flow

562

rate of 2 LPM for the PV/T-PCM systems. The highest exergy output obtained with the PV/T-

563

PCM is 134.10 W respectively. On the other hand, exergy efficiency keeps on decreasing with

564

increasing water flow rate which is due to the fact that with an increased flow rate of a volume of 25

ACCEPTED MANUSCRIPT

566

exergy efficiency is attainable at lower flow rates. The highest exergy efficiency obtained with the

567

PV/T-PCM is 12.19% respectively. 14

160

12

140 120

10

Exergy out (W)

water the irreversibility increases substantially causing greater exergy destruction. Hence, higher Exergy efficiency (%)

565

100

8

80

6

60

4

Exergy Effi (PV/T-PCM) Exergy out (PV/T-PCM)

2

40 20

0

0 0.5

1

2

3

4

Water flow (LPM)

568 569 570

Figure 7: Effect of water flow rate on exergy performance PV/T-PCM system 4.4 Comparative Performance Evaluation

571

In this section, the performances of a PV/T-PCM system have been presented in comparison

572

with a reference PV performance so that a relative ranking among the devices is possible. Figure

573

8 shows the performance of the PV/T-PCM system in comparison with the reference PV

574

performance in which 11.08% electrical efficiency of the PV/T-PCM is observed to increase by

575

1.20% as compared to the 9.88% PV electrical efficiency while the exergy efficiency of the PV/T-

576

PCM is enhanced by more than 5% as compared to the PV exergy efficiency. From Table 10, it

577

can be noticed that an exergy output of PV/T-PCM is increased by 58.89% as compared to the

578

reference PV.

26

Efficiency (%)

ACCEPTED MANUSCRIPT

PV/T-PCM 103 93 83 PV reference 73 63 53 43 33 7.01 7.09 6.43 6.55 5.64 23 9.45 9.78 9.88 9.73 9.75 13 3

87.72 73.7

77.06 73.87

12.19 11.65 10.55 10.2 9.93 10.29 10.62 10.9 10.89 11.08 0.5

Electrical

75.26

Exergy

1 2 3 Water flow (LPM)

4

Thermal

579 580 581

Figure 8: Energy and exergy efficiency comparesum performance of PV and PV/T-PCM for different mass flow rates

582 583

Table 10: Performance of electrical, thermal and exergy efficiency on PV and PV/T-PCM collector Average PV PV/T-PCM (optimum) Electrical efficiency (%) 9.75 11.08 Thermal efficiency (%) N/A 87.72 Exergy efficiency (%) 7.01 12.19 Exergy out (W) 75.21 134.10

584 585

4.5 Economic Analysis

586

An economic analysis mainly discusses the payback period of the system which can be

587

separated into two parts, i.e., the first is the solar PV panel and the second is the PV/T-PCM system.

588

These results can project a clear understanding between the renewable and the nonrenewable

589

economic performances. From equations (25), (26) and (27), it is possible to forecast the results

590

from the assumed years to draw a cash flow diagram for a solar PV panel system and to calculate

591

the total cost on a period of 6 years lifespan. Data from Table 5, 6 and 7 are required to calculate

592

the module’s lifespan at 10% interest rates of the cash flow. This analysis used some assumed

593

values to arrive at some pragmatic amount.

594 27

ACCEPTED MANUSCRIPT

595

(A) Cash Flow diagram for solar PV panel as flows:

596

0

597 598

5 6

15

MYR 100

MYR 100

25 Year MYR 100

599 600

MYR 2000

601

MYR 100

602

Figure 9: Solar PV panel cash flow diagram

603 604

Figure 9 illustrates the cash flow diagram of a solar PV module from year 0 to year 25 with

605

values and arrows showing the year and cost per 5-year period of MYR 100 (US$ 23.46). Zero is

606

the initial year, thus, MYR 2000 (US$ 469.25) is the initial cost plus MYR 100 (US$ 23.46) as the

607

installation cost. Whereas the annual running cost is zero. After 15 and 25 years later, MYR 100

608

(US$ 23.46) extra is added for some additional replacement of component parts.

609

Cost of using a solar PV panel:

610

For the first 5 years:

611

A.W)Solar PV = MYR -570.35 (US$ 133.82)

612

For the 6 years of usage:

613

A.W)Solar PV = MYR -495.13 (US$ 116.22)

614

For the 15 years of usage:

615

A.W)Solar PV = MYR -279.24 (US$ 65.51)

616

For the 25 years of usage:

617

It is assumed that by the 25th year the solar PV panel will again incur a cost of MYR 100 (US$

618

23.46) for additional replacement of component parts: MYR -232.36 (US$ 54.51).

619

For annual benefit calculation, the average PV power output for 6 hours data has been taken

620

form the experiment result. It is calculated, the 6 years cost benefit for PV panel is RM 524.25

621

(US$ 123.06), where cost of one unit (1 kWh) of electricity in Malaysia is MYR 0.3853 (Chua,

622

2018). From the equation (24), it is calculated, the payback period for PV panel is 6 years.

623 624

(B) Cash Flow diagram for solar PV/T-PCM system as flows: 28

ACCEPTED MANUSCRIPT

625 626

0

4

5

10

15

20

25 Year

627 628

MYR 1900

MYR 1900

MYR 1900 MYR 1900 MYR 1900

629 630 631

MYR 5604.53

632 MYR 100

633 634

Figure 10: Solar PV/T having PCM cash flow diagram

635

The thermal absorber and PCM materials costs are MYR 1750.77 (US$ 410.22) and MYR

636

1853.76 (US$ 434.35), respectively. Figure 10 illustrates the cash flow diagram of a PCM from

637

year 0 to year 25 with values and arrows showing the year and cost per 5-year period of MYR

638

1900 (US$ 445.22). From Table 5, 6 and 7, states that zero cost is encountered in the initial year,

639

thus, MYR 5604.53 (US$ 1,313.29) is the initial cost plus MYR 1900 as the installation cost.

640

Whereas the annual running cost is zero while the PCM materials 5 years later will need to be

641

replaced costing MYR 1900 (US$ 445.22) extra which is added to the additional replacement of

642

some component parts.

643

Cost of running a PV/T-PCM system:

644

For the first 4 years:

645

A.W)Solar PV/T-PCM = MYR -2209.00 (US$ 518.54)

646

For the first 5 years:

647

A.W)Solar PV/T-PCM = MYR -1816.05 (US$ 434.35)

648

For the 10, 15, and 20-year period:

649

A.W)Solar PV/T-PCM = MYR -1047.60 (US$ 245.51) for 10-year period,

650

MYR -809.79 (US$ 189.77) for the 15-year period, and

651

MYR -703.22 (US$ 164.78) for the 20-year period.

652

For the 25th year period:

653

It is assumed that at its 25th year period, it will again incur a cost of MYR 1900 (US$ 445.22)

654

for additional replacement of component parts: MYR -647.77 (US$ 151.78). 29

ACCEPTED MANUSCRIPT

655

The negative values in both cases are the cost value for the solar PV and PV/T-PCM systems.

656

For annual benefit calculation, the average PV/T-PCM power and heat gain for 6 hours data has

657

been taken form the experiment result. From the equation (24), the solar PV/T-PCM system cost

658

is definitely high as compared to the solar PV system, but after 4 years of usage, the cost benefit

659

value becomes MYR 3320.61 (US$ 779.48). The annual worth for the PV/T-PCM module is MYR

660

1111.61. That means the PV life cycle can be improved and used for a lower period. The result

661

shows that the solar PV/T-PCM system can be used for a longer lifespan than the solar PV/T

662

system.

663 664

5 Conclusions

665

The purpose of this study was to investigate the performance of a newly developed PV/T-PCM

666

module for use under typical Malaysian weather condition. Energy, exergy and economic analyses

667

have been conducted to analyze the total performance of the system from technical as well as

668

economic viewpoints. Comparative analysis was performed in the following manner: The

669

performance of a PV/T-PCM system has been compared with that of a reference PV module.

670

For PV/T-PCM system, both the maximum electrical power output and the maximum efficiency

671

are obtained at 4 LPM. The maximum power output is 160.29 W, which is almost 14% higher than

672

that of the reference PV module. The maximum electrical efficiency is 14.42%, which is 4.72%

673

higher than that of the reference PV. For every 100 W/m2 increase in irradiation level, PV/T-PCM

674

power output increases by 13.12 W, while electrical efficiency drops by 0.55%. Every 1°C

675

decrease in PV/T-PCM cell temperature is followed by an increases in output power by 8.76 W

676

and electrical efficiency by 0.37%. The maximum PV/T-PCM thermal efficiency is 87.72% with

677

a mass flow rate of 2 LPM, while the highest rise obtained is 26.40°C at 0.5 LPM. The maximum

678

PV/T-PCM exergy output of 134.10 W is attained at 0.5 LPM and the maximum average exergy

679

efficiency of 12.19% is obtained at a mass flow rate of 1 LPM.

680

The breakdown cost of a solar PV module is RM 2000 (US$ 469.25) which is expensive but

681

because of its long-term uses, it will be free of maintenance costs as based on the Annual-worth

682

methods from 5 to 10 years later. A phase change material costs approximately MYR 5604.53

683

(US$ 1,313.29) which is considered as a high investment cost but which can be free of maintenance

684

costs after usage of up to 4 years. PCM materials need to change every 5 or 6 years later which 30

ACCEPTED MANUSCRIPT

685

means that one time investment can last at least up to 5 years. If the system cost together with the

686

installation cost come around MYR 1900 (US$ 445.22), and after usage of up to 4 years as based

687

on the Annual-worth methods, then the cost benefit will be MYR 3320.61 (US$ 779.48). The

688

results of calculations on the cost analyses show that the PV/T-PCM systems are more economical

689

and become more attractive than the solar PV system operating alone in the long run, thus, it is

690

advantageous for the household family to use the solar water heater which can last up to a period

691

of at least 5 years.

692

Acknowledgements

693

Authors acknowledge the technical and financial assistance of UM Power Energy Dedicated

694

Advanced Centre (UMPEDAC) and the Higher Institution Centre of Excellence (HICoE) Program

695

Research Grant, UMPEDAC - 2016 (MOHE HICOE - UMPEDAC).

696 697

References

698 699 700 701 702 703 704 705 706 707 708 709 710 711 712 713 714 715 716 717 718 719 720 721 722 723 724

Abhat, A. (1983). Low temperature latent thermal energy storage system: heat storage materials. Sol Energy, 30, 313–332. Agarwal, A., & Sarviya, R. M. (2016). An experimental investigation of shell and tube latent heat storage for solar dryer using paraffin wax as heat storage material. Engineering Science and Technology, an International Journal, 19 619–631. Agyenim, F., Hewitt, N., Eames, P., & Smyth, M. (2010). A review of materials, heat transfer and phase change problem formulation for latent heat thermal energy storage systems (LHTESS). Renewable and Sustainable Energy Reviews, 14(2), 615-628. Al-Hinti, I., Al-Ghandoor, A., Maaly, A., Abu Naqeera, I., Al-Khateeb, Z., & Al-Sheikh, O. (2010). Experimental investigation on the use of water-phase change material storage in conventional solar water heating systems. Energy Conversion and Management, 51(8), 1735-1740. Beckmann, G., & Gill, P. V. (1984). Thermal energy storage: basics–design–applications to power generation and heat supply (course in mathematical physics). Berlin: Springer. Chua, J. (2018). Malaysia Has One Of The Lowest Domestic Electricity Prices In The World. http://www.rojakdaily.com/news/article/4384/malaysia-has-one-of-the-lowest-domesticelectricity-prices-in-the-world. Website. Dursun, B. (2012). Determination of the optimum hybrid renewable power generating systems for Kavakli campus of Kirklareli University, Turkey, . Renewable and Sustainable Energy Reviews, 16, 61836190. Fuqiao, W., Maidment, G., Missenden, J., & Tozer, R. (2002). A review of research concerning the use of PCMs in air conditioning and refrigeration engineering. Adv Build Technol, 1, 1273–1280. Garg, H. P., Mullick, S. C., & Bhargava, A. K. (1985). Solar thermal energy storage. Dordrecht, Holland: Reidel Publishing Company. Hammou, Z. A., & Lacroix, M. (2006). A new PCM storage system for managing simultaneously solar and electric energy. Energy and Buildings, 38, 258–265. Hasanuzzaman, M., Malek, A. B. M. A., Islam, M. M., Pandey, A. K., & Rahim, N. A. (2016). Global advancement of cooling technologies for PV systems: A review. Solar Energy, 137, 25-45. 31

ACCEPTED MANUSCRIPT

725 726 727 728 729 730 731 732 733 734 735 736 737 738 739 740 741 742 743 744 745 746 747 748 749 750 751 752 753 754 755 756 757 758 759 760 761 762 763 764 765 766 767 768 769 770

Hazami, M., Riahi, A., Mehdaoui, F., Nouicer, O., & Farhat, A. (2016). Energetic and exergetic performances analysis of a PV/T (photovoltaic thermal) solar system tested and simulated under to Tunisian (North Africa) climatic conditions. Energy, 107, 78-94. Hellstrom, B., Adsten, M., Nostell, P., Karlsson, B., & Wackelgard, E. (2003). The impact of optical and thermal properties on the performance of flat plate solar collectors. Renewable Energy, 28(3), 331-344. Ho, C. J., & Gao, J. Y. (2009). Preparation and thermophysical properties of nanoparticle-in-paraffin emulsion as phase change material. International Communications in Heat and Mass Transfer, 36(5), 467-470. Hossain, M. S. (2013). Thermal performance and economic analysis of solar photovoltaic water heater under the malaysian climatic condition. Thesis. Hossain, M. S., Pandey, A. K., Selvaraj, J. A. L., Rahim, N. A., & Hoque, K. E. (2015). Thermal and economic analysis of low-cost modified flat-plate solar water heater with parallel two-side serpentine flow Journal of thermal analysis and calorimetry, 123(1), 793-806. Hossain, M. S., Saidur, R., Fayaz, H., Rahim, N. A., Islam, M. R., Ahamed, J. U., & Rahman, M. M. (2011). Review on solar water heater collector and thermal energy performance of circulating pipe. Renewable and Sustainable Energy Reviews, 15(8), 3801-3812. Ibrahim, A., Fudholi, A., Sopian, K., Othman, M. Y., & Ruslan, M. H. (2014a). Efficiencies and improvement potential of building integrated photovoltaic thermal (BIPVT) system. Energy Conversion and Management, 77(Supplement C), 527-534. Ibrahim, A., Fudholi, A., Sopian, K., Othman, M. Y., & Ruslan, M. H. (2014b). Efficiencies and improvement potential of building integrated photovoltaic thermal (BIPVT) system. Energy Conversion and Management, 77, 527-534. Islam, M. M., Pandey, A. K., Hasanuzzaman, M., & Rahim, N. A. (2016). Recent progresses and achievements in photovoltaic-phase change material technology: A review with special treatment on photovoltaic thermal-phase change material systems. Energy Conversion and Management, 126, 177-204. Jamil, A., Kousksou, T., Zeraouli, Y., Gibout, S., & Dumas, J. P. (2006). Simulation of the thermal transfer during an eutectic melting of a binary solution. Thermochimica Acta, 441(1), 30-34. Joulin, A., Younsi, Z., Zalewski, L., Lassue, S., Rousse, D. R., & Cavrot, J.-P. (2011). Experimental and numerical investigation of a phase change material: Thermal-energy storage and release. Applied Energy, 88(7), 2454-2462. Jun, Z., Junfeng, L., Jie, W., & Ngan, H. W. (2011). A multi-agent solution to energy management in hybrid renewable energy generation system. Renewable Energy, 36 1352-1363. Kumar, S., & Tiwari, G. N. (2009). Life cycle cost analysis of single slope hybrid (PV/T) active solar still. Applied Energy, 86(10), 1995-2004. Kuznik, F., David, D., Johannes, K., & Roux, J.-J. (2011). A review on phase change materials integrated in building walls. Renewable and Sustainable Energy Reviews, 15(1), 379-391. Kylili, A., & Fokaides, P. A. (2016). Life Cycle Assessment (LCA) of Phase Change Materials (PCMs) for building applications: A review. Journal of Building Engineering, 6, 133–143. lazada.com.my. (2017). Thermal Conductive Grease Paste, https://www.lazada.com.my/products/sunshop-silver-compound-thermal-conductive-greasepaste-for-cpu-gpu-chipset-cooling-10g-i161646691s192553883.html?spm=a2o4k.searchlist.list.15.2fa431ebU4pBGt&search=1. Leland T, B., & Anthony J, T. (1998). Engineering Economy. Book. 4th Edition: ISBN: 0-070-115964-9., 46161.

32

ACCEPTED MANUSCRIPT

771 772 773 774 775 776 777 778 779 780 781 782 783 784 785 786 787 788 789 790 791 792 793 794 795 796 797 798 799 800 801 802 803 804 805 806 807 808 809 810 811 812 813 814 815 816 817 818

Lu, S., Zhao, Y., Fang, K., Li, Y., & Sun, P. (2017). Establishment and experimental verification of TRNSYS model for PCM floor coupled with solar water heating system. Energy and Buildings, 140, 245260. Martinopoulos, G., Missirlis, D., Tsilingiridis, G., Yakinthos, K., & Kyriakis, N. (2010). CFD modeling of a polymer solar collector. Renewable Energy, 35, 1499–1508. Michels, H., & Pitz-Paal, R. (2007). Cascaded latent heat storage for parabolic trough solar power plants. Solar Energy, 81(6), 829-837. Mohsen, M. S., Al-Ghandoor, A., & Al-Hinti, I. (2009). Thermal analysis of compact solar water heater under local climatic conditions International Communications in Heat and Mass Transfer, 36 (9), 962-968. Nahar, A., Hasanuzzaman, M., & Rahim, N. A. (2017). Numerical and experimental investigation on the performance of a photovoltaic thermal collector with parallel plate flow channel under different operating conditions in Malaysia. Solar Energy, 144(Supplement C), 517-528. Pandey, A. K., Hossain, M. S., Tyagi, V. V., Abd Rahim, N., Selvaraj, J. A. L., & Sari, A. (2018). Novel approaches and recent developments on potential applications of phase change materials in solar energy. Renewable and Sustainable Energy Reviews, 82, 281-323. Park, S. R., Pandey, A. K., Tyagi, V. V., & Tyagi, S. K. (2014). Energy and exergy analysis of typical renewable energy systems. Renewable and Sustainable Energy Reviews, 30, 105-123. Praveen kumar, B., Prince Winston, D., Pounraj, P., Muthu Manokar, A., Sathyamurthy, R., & Kabeel, A. E. (2017). Experimental investigation on hybrid PV/T active solar still with effective heating and cover cooling method. Desalination. Rahman, M. M., Hasanuzzaman, M., & Rahim, N. A. (2017). Effects of operational conditions on the energy efficiency of photovoltaic modules operating in Malaysia. Journal of Cleaner Production, 143(Supplement C), 912-924. Regin, A. F., Solanki, S. C., & Saini, J. S. (2008). Heat transfer characteristics of thermal energy storage system using PCM capsules: A review. Renewable and Sustainable Energy Reviews, 12(9), 24382458. Robles-Ocampo, B., Ruíz-Vasquez, E., Canseco-Sánchez, H., Cornejo-Meza, R. C., Trápaga-Martínez, G., García-Rodriguez, F. J., . . . Vorobiev, Y. V. (2007). Photovoltaic/thermal solar hybrid system with bifacial PV module and transparent plane collector. Solar Energy Materials and Solar Cells, 91(20), 1966-1971. Sarhaddi, F., Farahat, S., Ajam, H., Behzadmehr, A., & Mahdavi Adeli, M. (2010). An improved thermal and electrical model for a solar photovoltaic thermal (PV/T) air collector Applied Energy, 87(7), 23282339. Schmidt, F. (1981). Thermal energy storage and regeneration (series in thermal and fluids engineering). New York: McGraw-Hill. Sigma-Aldrich. (2013). ParaffinWax. http://www.sigmaaldrich.com/catalog/product/aldrich/327212?lang=fi®ion=FI. Simonetti, R., Molinaroli, L., & Manzolini, G. (2018). Development and validation of a comprehensive dynamic mathematical model for hybrid PV/T solar collectors. Applied Thermal Engineering, 133, 543-554. Struckmann, F. (2008). Analysis of a Flat-plate Solar Collector. http://www.ht.energy.lth.se/fileadmin/ht/Kurser/MVK160/Project_08/Fabio.pdf. . Heat and Mass Transport, Project Report. Sudhakar, K., & Srivastava, T. (2014). Energy and exergy analysis of 36 W solar photovoltaic module. International Journal of Ambient Energy, 35(1), 1-7. Telkes, M., & Raymond, E. (1949). Storing solar heat in chemicals-a report on the Dover house. Heat Vent, 46, 80–86. 33

ACCEPTED MANUSCRIPT

819 820 821 822 823 824 825 826 827 828 829 830 831 832 833 834 835

Tian, Y., & Zhao, C. Y. (2009). Heat transfer analysis for phase change materials (PCMs). In: Proceedings of the 11th International Conference on Energy Storage (Effstock 2009); Stockholm, Sweden. Tian, Y., & Zhao, C. Y. (2011). A numerical investigation of heat transfer in phase change materials (PCMs) embedded in porous metals. Energy, 36, 5539–5546. Tian, Y., & Zhao, C. Y. (2012). A Review of Solar Collectors and Thermal Energy Storage in Solar Thermal Applications. Applied Energy, 104, 538–553. Tian, Y., & Zhao, C. Y. (2013). Thermal and exergetic analysis of Metal Foam-enhanced Cascaded Thermal Energy Storage (MF-CTES). International Journal of Heat and Mass Transfer, 58(1), 86-96. Tyagi, V. V., Panwar, N. L., Rahim, N. A., & Kothari, R. (2012). Review on solar air heating system with and without thermal energy storage system. Renewable and Sustainable Energy Reviews, 16(4), 22892303. Yang, X., Sun, L., Yuan, Y., Zhao, X., & Cao, X. (2018). Experimental investigation on performance comparison of PV/T-PCM system and PV/T system. Renewable Energy, 119, 152-159. Zalba, B., Marı´n, J. M., Cabeza, L., & Mehling, H. (2003). Review on thermal energy storage with phase change: materials, heat transfer analysis and applications Appl Therm Eng, 23, 251–283. Zhao, C., Lu, W., & Tian, Y. (2010). Heat transfer enhancement for thermal energy storage using metal foams embedded within phase change materials (PCMs). Sol. Energy, 84, 1402–1412.

836 837 838 839 840 841 842 843 844 845

34

ACCEPTED MANUSCRIPT

846

Appendix

847

Appendix A: Hourly variation of different PV and PV/T-PCM parameters Tout -Tin

Ta

Tcell (PV/T-PCM)

Tcell (PV)

Solar radiation

80.00

1200.00

70.00

1000.00 800.00

50.00 40.00

600.00

30.00

400.00

20.00 200.00

10.00

0.00 10:00 10:15 10:30 10:45 11:00 11:15 11:30 11:45 12:00 12:15 12:30 12:45 13:00 13:15 13:30 13:45 14:00 14:15 14:30 14:45 15:00 15:15 15:30 15:45 16:00

AM AM AM AM AM AM AM AM PM PM PM PM PM PM PM PM PM PM PM PM PM PM PM PM PM

0.00

Solar radiation (W/m2)

Temperature (°C)

60.00

848 849

Figure A.1: Hourly variation of different PV and PV/T-PCM parameters (0.5 LPM) Tout -Tin

Ta

Tcell (PV/T-PCM)

Tcell (PV)

Solar radiation

80.00

1200.00

70.00

1000.00 800.00

Temperature (°C)

50.00 40.00

600.00

30.00

400.00

20.00 200.00

10.00

0.00

850

10:00 10:15 10:30 10:45 11:00 11:15 11:30 11:45 12:00 12:15 12:30 12:45 13:00 13:15 13:30 13:45 14:00 14:15 14:30 14:45 15:00 15:15 15:30 15:45 16:00

AM AM AM AM AM AM AM AM PM PM PM PM PM PM PM PM PM PM PM PM PM PM PM PM PM

0.00

35

Solar radiation (W/m2)

60.00

ACCEPTED MANUSCRIPT

Figure A.2: Hourly variation of different PV and PV/T-PCM parameters (1 LPM) Tout -Tin

Ta

Tcell (PV/T-PCM)

Tcell (PV)

Solar radiation

80.00

1200.00

70.00

1000.00

Temperature (°C)

60.00 800.00

50.00 40.00

600.00

30.00

400.00

20.00 200.00

10.00

0.00 10:00 10:15 10:30 10:45 11:00 11:15 11:30 11:45 12:00 12:15 12:30 12:45 13:00 13:15 13:30 13:45 14:00 14:15 14:30 14:45 15:00 15:15 15:30 15:45 16:00

AM AM AM AM AM AM AM AM PM PM PM PM PM PM PM PM PM PM PM PM PM PM PM PM PM

0.00

Solar radiation (W/m2)

851

Figure A.3: Hourly variation of different PV and PV/T-PCM parameters (2 LPM) Tout -Tin

Ta

Tcell (PV/T-PCM)

Tcell (PV)

Solar radiation

80

1200

Temperature (°C)

70

1000

60 800

50 40

600

30

400

20 200

10

0

854 855

10:00 10:15 10:30 10:45 11:00 11:15 11:30 11:45 12:00 12:15 12:30 12:45 13:00 13:15 13:30 13:45 14:00 14:15 14:30 14:45 15:00 15:15 15:30 15:45 16:00

AM AM AM AM AM AM AM AM PM PM PM PM PM PM PM PM PM PM PM PM PM PM PM PM PM

0

Figure A.4: Hourly variation of different PV and PV/T-PCM parameters (3 LPM)

36

Solar radiation (W/m2)

852 853

ACCEPTED MANUSCRIPT

Tout -Tin

Ta

Tcell (PV/T-PCM)

Tcell (PV)

Solar radiation

80

1200 1000

60 800

50 40

600

30

400

20 200

10

0

856 857

10:00 10:15 10:30 10:45 11:00 11:15 11:30 11:45 12:00 12:15 12:30 12:45 13:00 13:15 13:30 13:45 14:00 14:15 14:30 14:45 15:00 15:15 15:30 15:45 16:00

AM AM AM AM AM AM AM AM PM PM PM PM PM PM PM PM PM PM PM PM PM PM PM PM PM

0

Figure A.5: Hourly variation of different PV and PV/T-PCM parameters (4 LPM)

858 859 860 861 862 863 864 865 866 867 868 869 870

37

Solar radiation (W/m2)

Temperature (°C)

70

878

Irradiation (W/m2)

301.73976 352.57208 362.5594 376.94136 679.06382 873.85468 649.7198 702.5888 986.6802 968.06608 947.8432 983.725 946.56656 951.0376 988.2694 979.8846 975.0532 979.2238 877.52688 702.57376 536.30008 547.98488 379.37544 369.27432 377.11344

Electrical efficiency (%) 15

13

11

9

7

5

3 PV (%) PV/T-PCM (%) PV (W) PV/T-PCM (W)

15

13 120

11 100

9 80

7 60

5

3

PV (%) PV/T-PCM (%) PV (W) PV/T-PCM (W)

38 40

20

0 Electrical power (W)

Irradiation (W/m2)

875 876

Figure B.1: Effect of irradiation and cell temperature on electrical performance of PV/T-PCM

877

against the reference PV (0.5 LPM)

375.5812 307.12392 501.88104 518.01232 737.37114 756.69632 675.08328 641.0456 853.47 942.55368 986.0408 890.753 936.565 855.34008 883.4103 863.86852 947.74788 999.05568 836.5845 852.53268 699.23018 677.77102 612.74816 549.80488 368.92894

Electrical efficiency (%)

160

140

120

100

Electrical power (W)

ACCEPTED MANUSCRIPT

871

872

Appendix B: Effect of irradiation and cell temperature on electrical performance of PV/T-

873

PCM against the reference PV

874

80

60

40

20

0

160

140

ACCEPTED MANUSCRIPT

Figure B.2: Effect of irradiation and cell temperature on electrical performance of PV/T-PCM against the reference PV (1 LPM) 15

160 140

13

120 11

100

9

80 60

7 PV (%) PV/T-PCM (%) PV (W) PV/T-PCM (W)

5

40 20 0

363.21 375.82 485.86 505.23 701.06 673.90 745.99 717.37 983.11 920.98 919.46 825.25 979.49 927.87 808.34 960.16 902.76 915.56 629.73 899.37 615.28 482.50 466.93 302.81 395.38

3

Electrical power (W)

Electrical efficiency (%)

879 880

Irradiation (W/m2)

Figure B.3: Effect of irradiation and cell temperature on electrical performance of PV/T-PCM against the reference PV (2 LPM) 15

160 140

13

120 11

100

9

80 60

7

40 PV (%) PV/T-PCM (%) 20 PV (W) PV/T-PCM (W) 0

5

398.67742 481.90304 376.62516 448.94738 446.8594 623.42084 641.16164 742.99848 718.01232 821.71604 789.1218 812.88856 961.48432 877.0508 986.5018 989.11376 831.84964 984.63312 953.34688 925.79528 703.52116 606.71072 415.1922 416.3828 455.57084

3

Electrical power (W)

Electrical efficiency (%)

881 882 883

Irradiation (W/m2)

884 885

Figure B.4: Effect of irradiation and cell temperature on electrical performance of PV/T-PCM

886

against the reference PV (3 LPM)

39

15

180 160

13

140

11

120 100

9

80

7

60 PV (%) PV/T-PCM (%) PV (W) PV/T-PCM (W)

5

40 20 0

375.26 342.94 357.76 735.47 776.55 607.24 857.76 772.20 880.27 991.85 915.54 977.19 994.66 992.23 956.55 951.41 732.37 803.44 706.99 636.57 664.66 431.81 447.81 358.45 336.12

3

Electrical power (W)

Electrical efficiency (%)

ACCEPTED MANUSCRIPT

Irradiation (W/m2)

887 888

Figure B.5: Effect of irradiation and cell temperature on electrical performance of PV/T-PCM

889

against the reference PV (4 LPM)

890 891

40

ACCEPTED MANUSCRIPT

Highlights    

Study of novel two side serpentine flow based photovoltaic/thermal (PV/T) with PCM Self-sufficient PVT-PCM system with improved energy and exergy efficiencies Economic evaluation of the PV/T collector using cash flow analysis Maximum thermal and exergy efficiency is found to be 87.72% and 12.19% respectively