Table 1.
Summary of major past studies on PV performance evaluation conducted in Malaysia and other countries.
Fig 1.
Seasonal variation of rainfall in Peninsular Malaysia.
Fig 2.
Vernal/March equinox occurs when the sun directly shines the celestial equator.
This also happens in autumnal/September equinox. On both equinox days, tilt angle is 0°. Other days of the year, the earth axis is tilted at an angle of approximately 23.5° with respect to the eclipse on both solstice days. Reprinted from [43] under a CC BY license, with permission from UPM, original copyright 2016.
Table 2.
Specification of c–Si and a–Si PV modules.
Fig 3.
Outdoor electrical and environmental data collection setup for a–Si and c–Si module.
Location is at UPM solar farm, coordinate 22.945° North and 101.75° East. 15-18° tilt angle is maintained to install the modules on a closed–rack type roof-top facing the north. This direction makes the modules cooler by the blowing wind, from east to west. Transparent box contains ZigBeePRO distribution node consisted of environmental parameter measurement sensors, embedded board, and communication radio. Thermocouples measure the ambient and the modules’ temperature. Humidity and luminosity sensors measure the humidity and the solar irradiance respectively. Anemometer is installed separately for measuring wind speed. Reprinted from [43] under a CC BY license, with permission from UPM, original copyright 2016.
Table 3.
Sensors specification.
Fig 4.
Integration of sensors, embedded board, and communication module.
Sensors: thermocouples, luminosity or LDR, and humidity. Embedded board: refers to the microcontroller and smart metering board. ZigBeePRO: communication module. Micro SD: attached to embedded board for storing sensors data. Solar Analyzer: retrieved four electrical data, such as open circuit voltage, short circuit current, max voltage and max current of PV module. ZigBeePRO gateway: installed at the control centre for data acquision. LabVIEW program: monitoring SD card data from the control centre. Reprinted from [43] under a CC BY license, with permission from UPM, original copyright 2016.
Fig 5.
Statistical analysis of individual day solar irradiance with hourly average.
Red line marker denotes median values at each hour and black (×) marker refers mean value.
Fig 6.
Inverse proportional relation between relative humidity and solar irradiance.
The mathematical model is fitted to data point with R2 = 0.718. On day1, humidity is between 44.2 and 68.8% with corresponding irradiance of 150–830 . Day2 is drier than day1 based on humidity (33–67.8%) and irradiance (95–1100
). Humidity and irradiance on day3 were 35.4–68.3% and 72–920
respectively. On day4 (the driest), humidity and irradiance ranges are 25.7–64% and 96–1050
. Finally, on day5, humidity is observed to be 35–53% when irradiance is 180-1010
.
Fig 7.
Effect of module temperature (TM) and solar irradiance (Z) on the efficiency (η) from 8:30 to 17:30 (a) a–Si and (b) c–Si modules on medium luminous day; and (c) a–Si and (d) c–Si modules on high luminous day.
Fig 8.
Comparison between ambient (TA) and the modules’ temperature (TM).
Till 11:30, module temperature of c–Si is about 2.26% higher than a–Si. Opposite scenario is seen in the afternoon. The blowing wind maintains the modules’ temperature within 58°C, on average.
Fig 9.
Comparison between a–Si and c-Si modules’ temperature (TM) based on, (a) solar irradiance (Z) and (b) output power efficiency (OPE).
TM is positively correlated with solar irradiance and OPE. By extrapolating the both fitting lines is not valid as it will show modules stop working at 25°C.
Fig 10.
Statistical analysis of the five days’ module temperature and efficiency.
(a) linear trends of a–Si efficiency (R2 = 0.906); (b) non–linear trends c–Si efficiency (R2 = 0.961, for linear); (c) data deviation for both a–Si and c–Si are along the regression curve.
Fig 11.
Comparison of individual days efficiency against daytime (a) a–Si and (b) c–Si.
Similar efficiencies are observed on day4 and day5. Hourly maximum efficiencies of a–Si and c–Si are 3.9% and 11.4% respectively.
Fig 12.
(a) Five-day average efficiency with solar irradiance. Maximum, average, and minimum efficiencies are 3.5, 2.3, 0.57% (a–Si) and 9.8, 6.4, 1.4% (c–Si) respectively. (b) Changes in efficiency with daytime. Both modules follow similar changing rate of efficiency () against solar irradiance except at 11:30, 12:30, 14:00, and 16:15.
Fig 13.
Five-day average OPE of c–Si and a–Si modules against solar irradiance.
Maximum values of OPE for c–Si and a–Si are 76.33% and 84.60% respectively.
Fig 14.
Hourly average PR of c–Si and a–Si module against daytime and solar irradiance (Z).
The PR and solar irradiance are inversely proportional.
Table 4.
Regression analysis of models* (e.g. Y = τ × X + υ) with validation for UPM, Klang valley region (2.945° North 101.75° East) in Malaysia during dry season.
Table 5.
Comparative analysis among STC, experimental data and other researchers’ outcomes based on environmental and electrical parameters of c–Si and a–Si module.
Table 6.
Energy yield in kWh estimation during dry season (Jun–Jul) for NEM application in Malaysia.