Fig. 2: Estimated values of Module Temperature verses Time at Kuching from various Models

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5 World Appl. Sci. J., 14 (Special Issue of Food and Environment): 01-08, 011 Fig. : Estimated values of Module Temperature verses Time at Kuching from various Models Fig. 3: Estimated Module Temperature verses Solar Radiation at Constant Temperature Fig. 4: Estimated Module Temperature verses Solar Radiation at Constant Temperature 5

6 World Appl. Sci. J., 14 (Special Issue of Food and Environment): 01-08, 011 Fig. 5: Estimated Module Temperature verses Ambient Temperature at Constant Solar Radiation Fig. 6: Estimated Module Temperature verses Ambient Temperature at Constant Solar Radiation RESULTS AND DISCUSSIONS approaches 60 C in the month of April. This is due to the integration of heat loss coefficients and wind speed for It was exposed from the results, that Risser and balancing the equation. The lowest estimated module Fuentes (1983) model displayed highest values of module temperature values were observed in the Lasnier and Ang operating temperature with more than 50 C in the month (1990) and Ross (1976) models with annual average values of January and approximately 60 C in the month of of 38.9 C and 40.7 C respectively. The former model August with an yearly average of 56.1 C in Kuching as considered only the ambient temperature and solar illustrated in Figures 1 and. This may due to the radiation parameters and did not account the wind speed incorporation of ambient temperature, solar radiation and other losses in their model, whereas the latter model and wind speed coefficients in their model. The second proposed a wide range of coefficient values from 0.0 yearly mean highest value of 55.4 C was found in the per C to 0.04 per C. The coefficient used for this analysis model proposed by Duffie and Beckman (006) among 16 was 0.0 per C. It was hard to choose these values examined models. The values in the month of January because no criteria was suggested and provided by the were slightly less than Risser and Fuents model but investigators as shown in Table 1 and. It is inferred that 6

7 World Appl. Sci. J., 14 (Special Issue of Food and Environment): 01-08, 011 Risser and Fuents (1983) and Duffie and Beckman (006) different results under constant solar radiation and models displayed the highest estimated values for module ambient temperature conditions respectively. The operating temperature at Kuching, as these both models variation in results may be due to the use of different are incorporated the effect of all three influential variables, climatic conditions, configuration of PV parameters such as solar radiation, atmospheric modules and approach used by various researchers. temperature and wind speed in their models. Wind speed Based on the model results and observations Duffie is quite low in the equatorial latitudes, which results less and Beckman (006) model was preferred for size heat loss from the modules by convection and therefore optimization, simulation and design of solar photovoltaic models predicted higher values of module operating systems. The selected model was formulated on the basis temperatures. The models proposed by Servant (1985), of energy balance approach and was more realistic than Ross (1976 and 1986) exhibited lowest values, as they steady state approach models. It will give more precise considered wind speed as constant in their models. predictions during fluctuated operating conditions when The influence of solar radiation from 100 W/m to the intensity of solar radiation and temperature will 1000 W/m on module operating temperature has been change within a short period of time. investigated by keeping other parameters constant, such as ambient temperature at 30 C and wind speed at 1 m/s as REFERENCES shown in Figures 3 and 4. It is revealed that the maximum value was estimated by Duffie and Beckman (006) model 1. Garcia, M.C.A. and J.L. Balenzategui, 004. Estimation with 86.8 C of module operating temperature and 35.7 C of photovoltaic module yearly temperature and at the solar radiation of 100W/m and the second highest performance based on nominal operation cell values were estimated by Risser and Fuentes (1983) temperature calculations. Renewable Energy, models with 69.7 C and 44.3 C at 1000 W/m and 100 W/m 9: respectively. The Duffie and Beckman (006) model shows. Trinuruk, P., C. Sorapipatana and D. Chenvidhya, sharp gradient because the wind speed and atmospheric 009. Estimating operating cell temperature of temperature were kept constant. Hence, it is confirmed BIPV Modules in Thailand. Renewable Energy, that the model estimated the sharpness and rise of module 34: temperature with the increase of solar radiation at 3. Grunow, P., S. Lust, D. Sauter, V. Hoffmann, constant wind speed is applicable. The lowest module C. Beneking, B, Litzenburger and L. Podlowski, 004. temperature of 48 C, 48.1 C at 1000 W/m and 3. C and Weak light performance and annual yields of PV 31.8 C at the solar radiation of 100 W/m was modules and systems as a result of the basic demonstrated by Lasnier and Ang (1990) and Kou et al., th parameter set of industrial solar cells, 19 European (1998) models respectively. They did not consider the Photovoltaic Solar Energy Conference, Paris, France. effect of wind speed and heat loss factor and other 4. Huang, B.J., P.E. Yang, Y.P. Lin, B.Y. Lin, H.J. Chen, ambient temperature and solar radiation coefficients were R.C. Lai and J.S. Cheng, 011. Solar cell junction make constants, hence there results shows lower values temperature measurement of PV module. Solar of module temperature with respect to increase of solar Energy, 85: radiation. 5. Skoplak,i E. and J.A. Palyvos, 009. Operating temperature of photovoltaic modules, A survey of CONCLUSIONS pertinent correlations. Renewable Energy, 34: Hasan, M.A. and K. Sumathy, 010. Photovoltaic It was discovered from the results that most models thermal module concepts and their performance shown similar trend regarding module temperature analysis- A review. Renewable and Sustainable variation. However their values were quite distinct when Energy Reviews, 14: compared among each other. It was revealed that Risser 7. Klein, S.A., Calculation of Monthly Average and Fuentes (1983), Duffie and Beckman (006) models Insolation on Tilted Surfaces, Solar Energy, 19: 35. displayed highest values and the models proposed by 8. Shaari, S., K. Sopian, N. Amin and M.N. Kassim, 009. Lasnier and Ang (1990), Ross (1976) Kou et al., (1998) and The Temperature dependence coefficients of Servant (1985) established lowest results of module amorphous silicon and crystalline photovoltaic operating temperature for Kuching meteorological data. modules using Malaysian field test investigation. Moreover, the models demonstrated similar trend but American J. Appl. Sci., 6(4):

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