Available online at www.sciencedirect.com Energy Procedia 18 (212 ) 1421 1427 Analysis of Solar Irradiance and Solar Energy in Perlis, Northern of Peninsular Malaysia I. Daut a, Farhana Zainuddin a*, Y.M. Irwan a, A.R.N. Razliana a, a* a Electrical Energy and Industrial Electronic System Research Cluster, School of Electrical Systems Engineering, Universiti Malaysia Perlis (UniMAP), 1 Kangar Perlis, Malaysia. Abstract A photovoltaic (PV) systems output depends on the environmental parameters such as solar irradiance. The main priority in photovoltaic panels is electricity production. The aim of the presents work is to analyze the solar radiation received in Perlis, Northern of Peninsular Malaysia. The characteristic of solar irradiance is recorded per minutes for a month using Davis Vantage Pro2 Weather Station. The objective of this study is to analyze the electrical characteristic and relationships of solar irradiance and solar energy to the output of PV module respectively. 212 21 Published by by Elsevier Ltd. Ltd. Selection and/or and/or peer peer-review review under under responsibility of The of TerraGreen [name organizer] Society. Open access under CC BY-NC-ND license. Keywords: Solar irradiance; PV module; electrical characteristic 1. Introduction Environmental phenomenon, such as global warming and depletion of the ozone layer attributed to emissions from massive fuel combustion are slowly but surely causing widespread problems to every living thing on earth. Renewable energy, particularly photovoltaic technology is one very effective solution available today [1]. Solar energy is in the form of electromagnetic radiation with the wavelengths ranging from about.3μm (1-6 m) to over 3μm. Most of this energy is concentrated in the visible and the near-infrared * Corresponding author. Tel.:+129624949; fax: +4-979893. E-mail address: fhiyana_fm87@yahoo.com 1876-612 212 Published by Elsevier Ltd. Selection and/or peer review under responsibility of The TerraGreen Society. Open access under CC BY-NC-ND license. doi:1.116/j.egypro.212.5.158
1422 I. Daut et al. / Energy Procedia 18 ( 212 ) 1421 1427 wavelength range. The incident solar radiation sometimes called insolation, is measured as irradiance, or the energy per unit time per unit area or power per unit area [4]. Solar energy is one of the most valuable sources of energy and the only single energy source that can supply an additional energy the world needed over the next several decades. Photovoltaic (PV) cells, modules and arrays allow the direct conversion of solar energy into electrical energy. The maximum efficiency of Photovoltaic (PV) at around 9-12%, depending on the type of solar cells. The monthly average daily solar radiation in Malaysia is 4 5W/ m 2, with the monthly average sunshine duration ranging from 4 to 8 hours [2]. The ideal PV system would provide electricity with purely sinusoidal waveform (unity power factor) at the maximum power available from the solar radiation at the specific location of the PV system modules, and with no losses in the conversion and power conditioning system. The amount of solar radiant energy falling on a surface per unit area and per unit time is called irradiance. Solar radiation measurements are one of the important to most engineering application. It is used for the design, sizing, performance evaluation and research of solar energy application. In this study, the main focus is laying on the analysis performance of solar energy in Perlis. By varying the solar irradiance, the electrical performance will also be investigated. The instruments used to collect and record the irradiance and solar energy, DavisVantage Pro2 Weather Station. These weather stations have been installed at Electrical Energy & Industrial Electronic (EEIES) Research Cluster located at Kangar, Perlis. In addition, this weather station can also collect and record the ambient temperature which is one of the important parameter that can influence the PV cell on the PV conversion efficiency. 2. Theoretical basis 2.1 Solar irradiance The output power of a PV array depends on various environmental factors such as solar irradiance. In order to calculate the amount of energy absorb by the PV cell, one has to know the value of solar irradiation G(t). Applying the open circuit condition, I =, to the IV ( ) equation is given in [9]: Voc VT I = = Isc I e 1 The open circuit voltage is given by: V oc I = VT ln 1+ I sc From equation (2), it can be seen than the value of the open circuit voltage depends, logarithmically on the I sc / I ratio. This means that under constant temperature the value of the open circuit voltage scales logarithmically with the short circuit which, in turn scales linearly with irradiance resulting in a logarithmically dependence of the open circuit voltage with irradiance. This is also an important result indicating that the effect of the irradiance is much larger in the short circuit current than in the open circuit voltage. 2.2 Mathematical formulation The total energy, E c, absorbed by the PV cell is given by the following equation [8]: (1) (2)
I. Daut et al. / Energy Procedia 18 ( 212 ) 1421 1427 1423 E c = c g G(t) (3) Where: G(t) c g e monthly average value of solar irradiance. is the cell packing factor. It is defined as the ratio of area of solar cell to the area of blank absorber. The PV panel has been set up at the clear are. It is mean that PV cell can absorb 1% of solar irradiance. So, the cell packing factor is assumed to be 1. is cell absorptivity to sunlight. is a fraction transmitted through the front glass and for this study, low iron glass was used which is equal to.95. is the cell electrical efficiency. Incident solar irradiation is converted by the PV module with efficiency e and it can be calculate by using the following equation: e = [1-(T c T )] (4) Where: = (5) The value of is measured under Standard Test Conditions (STC) and is available in every solar panel datasheet. STC specifies a temperature T of 25ºC and a normal irradiance G of 1 W/m 2 with air mass 1.5 (AM1.5) spectrums. A is the area of the PV module, T c is the cell temperature, is the temperature coefficient of silicon cell, =.45 ºC -1. Polycrystalline silicon PV modules are used in this study. The insolation absorbed by the solar cell can be converted into electrical energy, E ce and the equations are shown respectively below, E ce = e g G(t) (6)
1424 I. Daut et al. / Energy Procedia 18 ( 212 ) 1421 1427 3. Result Analysis Fig. 1. (a)weather Station Data Centre; (b) Vantage Pro2 Weather Stations install at Cluster EEIES A second order polynomial equation was used to curve the real Weather Station data. The average solar radiance in April 211 has been choosing for this study and it varies throughout the day from 7.am until 7.pm. The solar irradiation is a function of time and the equation is shown below: G(t)= -2.3583t 2 + 529.3158t 267.5527 Where t is the time and the unit of t is minute. Solar irradiance W/m 2 9 8 7 6 5 4 3 2 1 7.am 8.am 9.am 1.am 11.am 12.pm 1.pm 2.pm 3.pm 4.pm 5.pm 6.pm 7.pm Time Fig 2. Monthly average value of solar irradiance
I. Daut et al. / Energy Procedia 18 ( 212 ) 1421 1427 1425 The curve seems to perfectly fit the real data in the morning, and the deviation of the curve started increasing after 11 am. Solar irradiance increases proportional with the time until it reaches the maximum and then begins to decline from evening until night. Solar Energy MJ/m 2.7.6.5.4.3.2.1 Day of year Fig 3. Incoming daily solar energy during a standard year The monthly solar energy shown in Figure 4 is collected in month March 211 until September 211 from Vantage Pro2 Weather Station. Once can observe that the pattern of solar energy available at northern of Peninsular Malaysia which received about 7 hour per day of sunshine. Through these seven months, the highest of solar energy recorded at Cluster EEIES was in April 211 with.5782mj/m 2 while the lowest recorded in this station was in June 211 only.4215mj/m 2. The electrical energy absorbed by PV panel on April 211 is presented below: 6 Electrical Energy kwh/m 2 5 4 3 2 1 7.am 8.am 9.am 1.am 11.am 12.pm 1.pm 2.pm 3.pm 4.pm 5.pm 6.pm 7.pm Fig 4. Total energy absorb by PV cell, E c The produced energy grows rapidly in the afternoon because solar radiation is larger at that time. One can notice that an increasing solar radiation, proportional to the electrical energy. Time
1426 I. Daut et al. / Energy Procedia 18 ( 212 ) 1421 1427 Solar Irradiance W/m 2 9 8 7 6 5 4 3 2 1 1.2 1.8.6.4.2 Solar Energy MJ/m 2 Time Solar Irradiance Solar Energy Fig 5. Solar irradiance and solar energy differences in April 211 PV module installed in Perlis is subject to high irradiation which favors their performance. The monthly solar irradiation and solar energy measured on site in Perlis using the Weather Station installed at the Electrical Energy and Industrial Electronic (EEIES) Research Cluster located at Kangar, Perlis. Average solar energy and level of solar irradiance determine are approximately the same. Figure 6 presents these results. Therefore, average monthly solar irradiance is proportional of average solar energy. Conclusion In this study, an evaluation was conductedd on typical data based on the daily-reports obtained from the Weather Station data. Although it is only a short-term view, the results of the study revealed the relationships in module performances based on solar irradiance and solar energy. We will continue to collect data in long terms (on monthly and annual basis) from now on in order to conduct an evaluation in terms of energy. Acknowledgements The author would like to Prof.Dr. Ismail Bin Daut and Mr. Mohd Irwan Bin Yusoff for their precious suggestion. The authors wish to thank School of Electrical System Engineering, University of Malaysia Perlis (UniMAP) for the technical and Fundamental Research Grant Scheme 211 for financial support as well.
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