Andrew Ragai Henry Rigit

Estimation of carbon footprints from diesel generator emissions

The aim of this paper is to estimate the amount of carbon footprints emitted from diesel generators in terms of carbon dioxide. A constant load demand of 1.05 kW per hour (6.3 kW/day) with six hours of operation of a diesel generator per day was selected for this analysis. The fuel consumption rate and carbon footprints in terms of carbon dioxide (CO2) were determined. It was discovered that emission of carbon footprints increased by five folds as emission factor was increased from 1 kg to 5 kgCO2/liter. Similarly, the increment of a single kW rated power diesel generator at a constant emission factor increases 1.1 to 1.2 times carbon footprint emissions. It is revealed that the efficiency of diesel generator is inversely proportional to its rated power, fuel consumption rate and CO2 emissions. Therefore, the rated power of selected diesel generator should be close to the required load demand.

Determination and comparison of different photovoltaic module temperature models for Kuching, Sarawak

This paper presents the approach of the different models that used to predict the module temperature, which is one of the most important factors responsible for lowering the performance of PV modules. The suitability of the models for PV module temperature prediction was examined in order to assess the anticipated behavior of module temperature increase with respect to ambient temperature and solar radiation. A total of 16 models has been selected and investigated by employing the monthly mean daily meteorological data of Kuching, Sarawak. It is revealed that most models exposed analogous tendency of module temperature and solar radiation intensity. However, their magnitude was quite dissimilar under constant solar radiation and ambient temperature conditions. This variation may be due to the use of different variables, climatic conditions, configuration of PV modules and approach used by various researchers.

A simple method for the estimation of global solar radiation from sunshine hours and other meteorological parameters

Estimation of solar radiation is considered as the most important parameter for the design and development of various solar energy systems. But, the availability of the required data is very scarce and often not readily accessible. The foremost objective of the present study was to evaluate the various models for the estimation of monthly average global solar radiation from bright sunshine hours and other meteorological parameters at four locations namely Sri Aman, Sibu, Bintulu and Limbang in the Sarawak State. For this purpose, six different solar radiation models, such as Angstrom, Glover, Tasdemirglu, Bahel, Hargreaves and Sayigh, have been investigated. The computed values are compared and assessed, but no relationships of results were found among selected models and with measured values of the nearest location. Hence, a simple and more flexible model is introduced based on the input data of bright sunshine hours, relative humidity and maximum temperature, for the prediction of available global solar radiation on a horizontal surface. The required data for the suggested model is usually available in the most meteorological sites. The proposed model demonstrated acceptable results, and statistically displayed lower RMSE and MBE as compared to the examined models. It could be a good estimator for predicting the global solar radiation in coastal and humid areas.

An Improved Mathematical Model for Computing Power Output of Solar Photovoltaic Modules

It is difficult to determine the input parameters values for equivalent circuit models of photovoltaic modules through analytical methods. Thus, the previous researchers preferred to use numerical methods. Since, the numerical methods are time consuming and need long term time series data which is not available in most developing countries, an improved mathematical model was formulated by combination of analytical and numerical methods to overcome the limitations of existing methods. The values of required model input parameters were computed analytically. The expression for output current of photovoltaic module was determined explicitly by Lambert W function and voltage was determined numerically by Newton-Raphson method. Moreover, the algebraic equations were derived for the shape factor which involves the ideality factor and the series resistance of a single diode photovoltaic module power output model. The formulated model results were validated with rated power output of a photovoltaic module provided by manufacturers using local meteorological data, which gave ±2% error. It was found that the proposed model is more practical in terms of precise estimations of photovoltaic module power output for any required location and number of variables used.

Life cycle cost analysis of a standalone PV system

The purpose of this paper is to assess the viability of standalone photovoltaic (SAPV) systems for the supply of electricity in remote areas of Sarawak. In order to achieve the objectives, the life cycle cost (LCC) of a SAPV system was computed by means of net present value (NPV) technique. All anticipated costs were discounted to their present values by considering the time value of money. It was found that the capital cost makes up around 58% and future costs shares 42% of all expenses. PV modules contribute 9% and battery bank shares 52% with almost 8 days of autonomy at LLP of 0.01. Controller adds 5%, inverter 8%, civil work 17% and O&M 9% of total life time system cost. The estimated net energy cost from SAPV system was found to be US

Degradation of a dielectric barrier discharge plasma actuator

2.5/kWh, which is 20 times higher than average electricity tariff in Malaysia. It is concluded that the SAPV systems could only be preferred where the extension of power transmission lines is expensive for the supply of electricity in isolated areas.

Recent developments in immobilizing titanium dioxide on supports for degradation of organic pollutants in wastewater- A review

Dielectric barrier discharge is vulnerable to ion bombardment, radical species or ultraviolet radiations that can be emitted by plasma filaments in air under atmospheric pressure. In our experiments, traces of degradation on the actuator surface can be observed by naked eye after the discharge operation. The degradation could come from the non-uniformity of the electric field. Despite the degradation marks, some scratches due to the corona discharge process can be seen on the dielectric surface. The parametric study in this study reveals that the degradation on the actuator panel is subjected to a failure rate that increases with the cumulative time of plasma operation and the magnitude of supplied voltage. Besides, this study suggests that the severity of degradation can be lessened for a symmetric and larger gap design plasma actuator, since the concentration for the ion bombardment can be weakened at a particular discharge area.

3D Modeling and Simulation of Electrohydrodynamic Ion-Drag Micropump with Different Configurations of Collector Electrode

This review focuses on the various types of supports used for immobilization of titanium dioxide nanomaterial catalyst for degradation of organic pollutants in wastewater. Several supports suitable to particular immobilization technique used for the degradation of pollutants in wastewater streams are explained. In general, a coating of catalyst on supports is carried out either by physical (e.g., thermal treatment) or by chemical (e.g., sol–gel). Among a range of the supports used, some of the prominent ones include glass, silica, activated carbon, stainless steel, cellulose, clay. Also, characterization methods in use such as X-ray diffraction, transmission electron microscope, scanning electron microscope, and UV-spectroscopy are discussed. The operating parameters such as temperature for the selected immobilization techniques are also explained.

Computational modeling and simulation of electro- hydrodynamic (EHD) ion-drag micropump with planar emitter and micropillar collector electrodes

This paper presents 3D simulation work for ion-drag micro pump. The commercial simulation software Comsol Multiphysics 4.2 was used to model and simulate ion-drag micro pump for three different configurations of collector electrode. The purpose of the simulation was to investigate the ways to improve the performance of the micro pump and analyze the effect of the electric field, fluid velocity and pressure gradient on the different design of the micro pump. The initial simulation patterns reveal the behavior of the electric field, fluid velocity and pressure gradient in the domain of each of the design of the micro pump. From the simulation results it is observed that at the top of the flow channel the fluid flow and pressure field is low because the driving electric body force is stronger near the electrodes surface and weaker at the top regions of the micro channel.

Parallel computation of electric potential in the EHD ion-drag micropump and the performance analysis of the parallel system

Computational models can be used to simulate a prototype of electrohydrodynamic (EHD) ion-drag micropump with planar emitter and micropillar collector electrodes. In this study, a simple and inexpensive design of an ion-drag micropump was modeled and numerically simulated. A three-dimensional segment of the microchannel was simulated by using periodic boundary conditions at the inlet and outlet. The pressure and velocity distribution at the outlet and in the entire domain of the micropump was obtained numerically. The effect of the gap between the emitter and the collector electrode, width and the height of micropillar and flow channel height was analyzed for optimum pressure and output flow rate. The enhanced performance of micropump was compared with existing designs. It was found that the performance of micropump could be improved by decreasing the height of micropillar and the gap between both electrodes. The numerical results also show that a maximum pressure head of about 2350 Pa and maximum mass flow rate 0.4 g min−1 at an applied voltage 1000 V is achievable with the proposed design of micropump. These values of pressure and flow rate can meet the cryogenic cooling requirements for some specific electronic devices.