Temperature Reduction to Enhancing Solar Panel Performance in Tropical Climate

The characteristics of climate in a region also influences the performance of solar panels, the characteristics are the intensity of solar irradiance, temperature, wind speed and humidity. An evaluation of the performance of solar panels needs to be done regarding the tropical climate in Indonesia. This evaluation is needed to determine how large the resulting energy production that will be used for the benefit of both technical and investment for Solar Power Plant. The purpose of this study was to examine the effect of wood powder composite board material in reducing the surface temperature of solar panels in order to increase the efficiency of energy conversion. The type of solar panel used is 50 Wp Polycrystalline. The results showed that the average of solar radiation is at 690 W/m2 resulting in an average current value of 1.8 A (with board dampers) and 1.68 A (without the board damper). While the average temperature of a solar panel without a damper is 36.4 ° C while the damping board drops to 34.6°C. Consequently increasing the output voltage level from 20,38 V to 20,55 V, This change also results in an increase in output Solar panel power on average from 47,8 Wp (without damper board) to 48,2 Wp (with damper board), with a reduction in power losses from 2,3 Wp to 1,8 Wp.


Introduction
The production of solar energy is carried out through the process of converting solar energy into electricity, in which it is very dependent on the climate or environmental parameters of a particular region. These parameters are the intensity of solar irradiance, temperature of solar panels, wind speed and humidity. Solar panel testing is mostly done in subtropical areas, so these results do not necessarily represent tropical conditions in general, including Indonesia. The tropical environment has distinctive characteristics namely [1] : 1. Having high temperatures ranging from 18-40ºC which can cause an increase in solar panel temperatures at 90ºC so it can reduce the performance of solar panels. 2. The high humidity level is 35-85% with low wind speeds ranging from 0.2 m/s. 3. Cloudy tendency and high rainfall. This condition causes the low brightness index which has an impact on the performance of solar panels. Based on these characteristics, an evaluation of the performance of solar panels needs to be done to see how much energy production is produced because a typical tropical climate will cause deviations from the parameters of the Standard Test Condition (STC) [2]. The aim of this research was to see the effect of wood powder composite board material in reducing heat on the surface of the solar panel so it can increase the efficiency of solar panel energy conversion.

Solar Energy
The sun supplies energy to the earth in the form of radiation. Without irradiance from the sun, life on earth would not work. Every year there are about 3.9 x 1024 Joules ~ 1.08 x 1018 kWh of solar energy on the surface of the earth, this means the energy received by the earth from the sun is 10,000 times more than the global primary energy demand each year and more than the total available reserve of energy available on earth. The intensity of solar radiation outside the earth's atmosphere depends on the distance between the earth and the sun. Throughout the year, the distance between the sun and the earth varies between 1.47 x 108 km to 1.52 x 108 km. Consequently, irradiance E 0 fluctuated between 1,325 W / m 2 to 1412 W /m 2 . The average value of this irradiance is called the solar constant. Solar constant E 0 = 1367 W / m 2 [3] .

Solar Cell Model Circuit
Modules of solar cells are generally made from silicon or gallium arsenide materials, and other building materials. The main part of the solar cell that is the pn junction or equivalent to the Schottky junction is needed for the influence of the solar cell on changes in light rays or solar irradiation. From the image equivalent, solar cell circuit can be modelled using a block diagram on Simelectronic. The most important component influencing this simulation is the photovoltaic (PV) cell model. Modelling of solar cells includes obtaining the characteristic value curves of VI and VP according to simulations of actual environmental conditions. The approach to the representation of solar cell circuits is a diode. In simelectronic modelling, solar cell blocks have been provided which contain parameters such as Isc, Voc , solar irradiance and other input variables [5].

Required Data
The data collection was carried out for 7 days starting from December 23, 2019 until December 29, 2019 with a time span of testing for 10 hours from 08.00 to 17.00 located in Ternate (0° 47'45.0 "N and 127° 22'22.7" E) . The data needed was in the form of environmental data that is solar irradiance, and temperature and electrical parameter data which are current, voltage and electrical power.

Composite Damper Board
In this research, reducing heat on solar panels was done by using a composite board made from sawdust. Wood dust was mixed with 70% by weight of PVAc in a plastic bath and stirred manually. The mixture was put into a mold with a size of 25 cm x 25 cm which was previously sprinkled with 15% by weight of PVAc. After the core has been sprinkled, then the top surface was re-sprinkled with 15% by weight of sawdust. After the mixture was printed, it was then placed between two aluminum plates. The mixture was pressed at a temperature of 1800ºC with a pressure of 25 kg / cm 2 for 20 IOP Publishing doi:10.1088/1757-899X/1125/1/012062 3 minutes. After pressing, the resulting board was left for 30 minutes to make the sheet harden. The conditioning was carried out for one week to release residual stress and achieve water content distribution

Solar Panel Specification
The solar panels used in testing are polycrystalline types with the following specifications:

Measurement Device
Measurements done in this study were the Pyranometer (Meteon) gauge for solar irradiance measurements and the EurotestPV M1 3108 Metrel to measure environmental parameters namely solar temperature and irradiance as well as electrical parameters such as voltage, current and electric power. Besides, it was also used several manual thermometers, and digital and analog multi meters. The electrical power provided by solar cells is:

Calculation Model
The average solar panel output is: The equation of power losses as follows [6]: Figure (4) shows that the tendency of increasing solar irradiance also influences the changes in current on both solar panels with and without damping boards. This curve shows that with the same amount of solar radiation, a solar panel with a temperature damping board has a higher current value than a solar panel without a temperature damping board. Average of the highest solar irradiance of 530 W / m 2 generates a current value by an average of 1.43 A (with board dampers) and 1.3 A (without the board damper). The tendency of an increase in current caused by an increase in solar irradiance was also shown in previous studies [3]. This is consistent with the theory as illustrated in the IV curve ( Figure 5) that a current short circuit (Isc) depends linearly on irradiation, an increase in irradiation at various levels contributed directly to the increase in the current [7].

Correlation of Temperature to Voltage
These results indicate that temperature's changes directly affected the voltage produced by the solar panels, as shown in Figure 6.

Losses Power and Output Power
The performance of solar panels is greatly influenced by temperature factors. If the temperature is higher than the standard temperature (STC) which is 25 o C, then this solar panel will experience a loss in maximum output power [6], as the purpose of this study is to reduce solar panel heat by using a damping board. Based on this study, solar panel with board reducer has a lower temperature which can reduce the losses compared to solar panels without temperature damper. The test results can be seen in Figure 8. In this graph, it shows that the temperature's average was 35.6 o C then the losses generated by the solar panels without damper was 2.3 Wp, while solar panels with a dampening board was lower which was equal to 1.8 Wp. Reduction of losses due to a decrease in the temperature of the solar panel is reduced by the damping board, directly increases the power output of the solar panel. Figure 9 shows that a solar panel with a damping board is able to increase solar panel output on average from 47.8 Wp (without a damping board) to 48.2 Wp.