Characteristic Analysis of Photovoltaic On-Grid System In Tropical Region For Weather-Corrected Performance Ratio Calculation Method Implementation

Indonesia has different weather factors than the subtropical climate that influences the performance indicators of photovoltaic systems. One of them is performance ratio that is affected by temperature factors. NREL proposes calculation method of Weather-Corrected Performance Ratio for correcting factors (temperature) in calculation performance ratio of photovoltaic systems. However, the implementation of this method in real operating condition of photovoltaic system especially in the tropics, has not received special attention. In addition, temperature coefficient of power photovoltaic (δ) in Standard Test Condition, is used in the calculation method may be different in real operating condition. This study was conducted to determine the effects of weather-corrected performance ratio method and to know characteristic of temperature coefficient of power photovoltaic (δ) as factors in of weather-corrected performance ratio method, in real operating condition especially in tropics. Through analysis photovoltaic system data from the data logger it is found that the range values of weather-corrected performance ratio are greater than conventional methods, with a maximum increase of 2.43%. Moreover it is found that because average temperature of tropical climate is higher than subtropical climate, it makes the percentage of power decrease to rise in temperature (δ) in tropical climate is higher than subtropical climate.

Influence of furnace tube shapeon thermal strain of fire-tube boilers

The aim of this paper is to use numerical analysis and fine element method-FEM to investigate the influence of furnace tube shape on the thermal strain of fire-tube boilers. Thermal stresses in corrugated furnace tubes of different shape, i.e. with different corrugation pitch and depth, were analysed first. It was demonstrated that the thermal stresses in corrugated furnace tube are significantly reduced with the increase of corrugation depth. Than deformations and stresses in the structure of a fire-tube boiler were analysed in a real operating condition, for the cases of installed plain furnace tube and corrugated furnace tubes with different shapes. It was concluded that in this fire-tube boiler, which is of larger steam capacity, the corrugated furnace tube must be installed, as well as that the maximal stress in the construction is reduced by the installation of the furnace tube with greater corrugation depth. The analysis of stresses due to pressure and thermal loads pointed out that thermal stresses are not lower-order stresses in comparison to stresses due to pressure loads, so they must be taken into consideration for boiler strength analysis.

Study on Particle Size Distribution of Diesel Bus Fueled with Biodiesel under Real Operating Condition

With the use of the Engine Exhaust Particle Sizer (EEPS) developed by TSI, particle size distribution characteristics of China-IV diesel bus fueled biodiesel are studied under real operating condition. Four mixtures of volume ratio between restaurant waste oil and China-IV diesel 5%, 10%, 20%, 50% respectively (marked separately by BD5, BD10, BD20, BD50), pure biodiesel (BD100) and pure diesel (BD0) were tested. The results indicated that the average velocity of diesel bus is 18km/h. Of the entire operating time, idle operating period accounts for 30%, low and medium velocity 58%, and acceleration and deceleration 89%. In different velocity ranges, the size distribution of particulate number emissions (PNSD) is bimodal; in different acceleration ranges, PNSD shows a gradual transition from bimodal shape to unimodal when bus operation switches from decelerating to accelerating status. Biodiesel blended with higher mixture ratios show significant reduction in PN emissions for accumulated modes, and particulate number emission peaks move towards smaller sizes; but little change was obtained in PN emissions for nuclei modes with its particulate size of peak sustains around 10nm.