Monthly mean hourly global solar radiation estimation

In this paper, selected empirical models were used to estimate the monthly mean hourly global solar radiation from the daily global radiation at three sites in the east coast of Malaysia. The purpose is to determine the most accurate model to be used for estimating the monthly mean hourly global solar radiation in these sites. The hourly global solar radiation data used for the validation of selected models were obtained from the Malaysian Meteorology Department and University Malaysia Terengganu Renewable Energy Station. In order to indicate the performance of the models, the statistical test methods of the normalized mean bias error, normalized root mean square error, correlation coefficient and t‐statistical test were used. The monthly mean hourly global solar radiation values were calculated by using six models and the results were compared with corresponding measured data. All the models fit the data adequately and can be used to estimate the monthly mean hourly global solar radiation. This study finds that the Collares‐Pereira and Rabl model performed better than the other models. Therefore the Collares‐Pereira and Rabl model is recommended to estimate the monthly mean hourly global radiations for the east coast of Malaysia with humid tropical climate and in elsewhere with similar climatic conditions

Wave energy potential of peninsular Malaysia

Wave power potential along the east coast of Peninsular Malaysia, facing South China Sea, bounded by latitudes 3.50 N and 6.5o N and longitudes 1020 E and 104.0o E, is investigated based on two-hourly data, covering a 12-year period. The correlation between maximum wave height (Hmax) and significant wave height (Hs) for the east coast of Peninsular Malaysia can be given by01324.0494.1max+=sHH. The values of peak periods (Tp) and mean periods (Tmean) can be correlated with new model as Tmean = a1 * exp - ((Tp -b1)/c1)2 + a2 * exp -((Tp -b2)/c2)2 + a3 * exp - ((Tp -b3)/c3)2 where, a1 = -269.9, b1 = 9.609, c1 = 2.225, a2 = 271.9, b2 = 9.615, c2 = 2.242, a3 = 3.254, b3 = 6.903 and c3 = 7.812. Total wave energy was around 1.8 x 107 Wh/m in an average year, whereas the average wave power less than 6500 W/m. More than sixty percent of the annual wave energy is provided by significant wave heights less than 1.2 m. The wave peak periods less than 8 s accounted for more than seventy percent of total wave energy. The main directions in terms of wave energy for whole year are north, which accounts for more than 40%, followed at some distance by northeast, southwest and south. During northeast monsoon season, in general main directions in terms of wave energy are north and northeast, which accounts more than 80% of total wave energy

Wave climate assessment in the coast of Merang–energy and Mariculture perspective

Ocean waves are a power-dense, predictable source of clean and sustainable energy that has not yet been exploited to any significant extent in Malaysia. The lack of suitable sheltered sites is forcing mariculture farmers to move to more exposed offshore locations in order to provide for continued growth in the industry. However, as farmers move to more exposed sites for on-growing, extreme wave climate conditions must be regarded as a normal environmental condition. The present work aims to evaluate the wave climate condition in Merang, which is traditionally considered as being more energetic. The study was based on data collected during the period of 2008 and 2010. From the analysis following features of the wave climate in the area of study was identified. The months November to January has the highest probability of occurrence of waves with significant wave heights greater than one meter. The frequency of occurrence of wave heights l e s s t h a n 0 . 5 m occurred approximately equally in May, June, July and August. The wave mean periods greater than 5 s were encountered in November, December and January. In general, the wave mean periods were greater than 3s through out the year. The dominant wave direction was from the northern sector accounted more than 64% and the southern sector percentage was around 20%. Therefore, potential wave renewable energy is mainly available during November to January. However, system for mariculture in this location should be designed to take into account these wave climate conditions. This analysis is a prerequisite for further investigations extended in time and area of coverage

Estimating Photovoltaic modules operating temperatures for renewable solar energy application

The operating cell temperatures of photovoltaic (PV) modules directly affect the performance of the PV system. Commonly two steady state approach prediction models are used to estimate the PV modules cell temperatures, the nominal operating cell temperature model and the Sandia National Laboratory temperature prediction model. In this study the Sandia National Laboratory temperature prediction model was used to predict the PV modules temperatures of Renewable Energy Research Center PV installation at Universiti Malaysia Terengganu. It was found that, in general, the model tends to give better results of temperature prediction. In this analysis more than 4630 PV cell temperature data were used. The MBE, NMBE, RMSE, NRMSE and correlation coefficient of predicted and measured PV cell temperatures are -0.3490 oC,-0.7328%, 1.3571 oC, 2.8492% and 0.9763, respectively. The statistical results show that the model can be used to predict the PV cell temperatures with an error of less than 3%. It can be seen from the results, that the predicted PV cell temperatures show a good correlation with the measured data. As a conclusion, the PV cell temperatures can be estimated using a new linear model based on the steady state approach prediction model

Hourly global solar radiation for Kuala Terengganu of Malaysia

In this paper, six selected empirical models were used to estimate the hourly global solar radiation from the daily global radiation in Kuala Terengganu on the east coast of Malaysia. The purpose is to determine the most accurate models to be used for estimating the hourly global solar radiation. The measured hourly global solar radiation data used for the validation of selected models were obtained from the Malaysian Meteorology Department and University Malaysia Terengganu Renewable Energy Station for the period of 2004–2008. In order to indicate the performance of the models, the statistical test methods of the normalized mean bias error, normalized root mean square error, correlation coefficient and t- statistical test were used. The hourly global solar radiation values were calculated by using six models and the results were compared with corresponding measured data. All the models fit the data adequately and can be used to estimate the hourly global solar radiation. This study finds that the Collares-Pereira and Rabl model performed better than other models. Therefore the Collares-Pereira and Rabl model is recommended to estimate the hourly global radiations for Kuala Terengganu and elsewhere with similar climatic conditions

Assessment and characterisation of renewable energy resources: a case study in Terengganu, Malaysia

Accurate information on the renewable energy density at a given location is essential for the development of renewable energy-based projects. This information is used in the design of a project, in cost analysis, and in calculations on the efficiency of a project. As the renewable energy data are not available for most areas in Malaysia, this study is significant for establishing renewable energy data for Terengganu, Malaysia. The data used in the present study obtained from 2004 to 2008 were used to investigate the solar potentials, and also dataset from 2004 to 2007 were used to investigate the wind potentials and the dataset from 1998 to 2010 were used to investigate the wave potentials. MATLAB was used to process raw data to generate useful renewable energy characteristics. The average yearly cumulative irradiation for Terengganu was 6905.8 MJ/m2 per year. The monthly average clearness index varied between 0.42 and 0.64. The average cleamess index value was approximately 0.53. High wind speed was recorded during the northeast monsoon at an average of 3.9m/s. The potential wind power generated reached 84.55 W/m2 with a probability time factor value of 0.68. Therefore, small wind machines could be used to provide power during northeast monsoon. The total wave energy density was found to be 17.69 MWh/m in an average year. It may be concluded that regions along the coast of Terengganu can consider northeast monsoon period for wave energy exploitation. Adoption of solar and wave technology in Terengganu will be very advantageous based on solar and wave power densities. The wind power density in Terengganu was seen to be less encouraging. Compared with wind power potential, solar and wave resources were seen to be well distributed more evenly throughout the year. This was seen as a favourable indication for erection of hybrid renewable energy systems in the study location

Estimation of global solar irradiation on horizontal and inclined surfaces based on the horizontal measurements

Solar radiation data are essential in the design of solar energy conversion devices. In this regard, empirical models were selected to estimate the global solar radiation on horizontal and inclined surfaces. The hourly solar radiation data measured at the study area during the period of 2004e2007, were used to calculate solar radiations using selected models. The selected models were compared on the basis of statistical methods. Based on the results, a new model, H/Ho ¼ 0.19490 þ 0.4771(n/N) þ 0.02994 exp(n/N) has been developed, based on Kadir Bakirci linear exponential model. This is highly recommended to estimate monthly mean daily global solar irradiation, on a horizontal surface. Further, a model to convert horizontal solar global radiation to that of radiation on a tilted surface is also presented. It is based upon a relatively simple model proposed by Olmo et al. which requires only measurements of horizontal solar radiation. The developed model appears to give excellent results and has the advantage of being relatively simple for applications. The present work will help to improve the state of knowledge of global solar radiation to the point where it has applications in the estimation of global solar radiation, both on horizontal and inclined surfaces

A review of ocean wave power extraction: the primary interface

This paper aims to describe the importance of data, data collection methods, parameters to estimate the potential of wave energy and environmental impacts. The technical and economical status in wave energy conversion is outlined. Power and energy efficiency relationships are discussed. Many different types of wave-energy converters have been detailed. The progress in wave energy conversion in Malaysia is reviewed

Feasibility of using solar assisted rigid wind–sail as a power saving device on boats

The usage of alternative energy beside fossil fuel in maritime industry is necessary due to the fluctuating fuel cost. In order to reduce the operational cost by reducing the fuel consumption, some ships are equipped with solar-wind assisted devices. The lower oils consumption in ships could reduce environmental pollutions and increase cruising range. This study investigates the feasibility of using solar assisted rigid wind–sail as a power saving device on University Malaysia Terengganu’s (UMT) research boat. The attachment of solar assisted rigid wind-sail device may affect the performance, operation and stability of the boat. Generally, the performance of boat will increase when there are additional energies. Thus, the operational cost of the boat may decrease due to lower oil usage. Attempts were made to study the feasibility of using solar assisted rigid wind-sail in technical aspects including stability and performance as well as operational and economical aspects. The results of the study shown that the application of solar assisted rigid wind-sail to UMT research boat reduced the annual cost of operation from USD 20390 to USD 17815.9. It can also save up to 20% of power consumption. Further, the attachment of solar assisted rigid wind-sail to UMT research boat does not affect the stability of the boat and the stability of boat still meet the IMO requirement. Therefore, it can be summarized that the solar assisted rigid windsail has a high potential as an alternative to the conventional fossil fuel ships in the future

Ocean wave measurement and wave climate prediction of peninsular Malaysia

This paper presents wave measurement and wave climate prediction within Peninsular Malaysia. Rayleigh and Weibull density functions were used to predict wave heights. The total wave energy density was found to be 17.69 MWh/m within an average year, whereas average wave power density varied from 0.15 to 6.49 kW/m. Furthermore, more than 60% of the annual wave energy was caused by wave heights between 0.2 to 1.2 m. Waves with peak periods between 2 and 8 s accounted for more than 70% of the total wave energy. The extreme significant wave heights were predicted, using Gumbel, Weibull and Generalised Pareto distributions, as having return periods of 10 to 200 years for the same locations. The extreme significant wave heights varied from 2.6 to 3.4 m for the aforementioned return periods. The results of the present study will contribute greatly to the design of ocean engineering projects