Advanced Materials Research Vols. 931-932

Abstract: This paper presents the investigation on deterioration of PV modules installed in Thailand. The modules under this study were dismantled and collected from KMUTT installation in the Buriram province. Modules were same model of modules that were installed over a thousand of solar water pumping systems and battery charging stations by Green E-san project since end of the 1980's and in earlier of 1990's. There are 35 modules, single crystalline silicon sized 47 Wp, in this study that were exposed in the field with less than 15 years. The experiments consist of visual inspection and measurement of performance at standard test condition (STC 1000 W/m², 25 °C AM1.5) according to IEC61215:2005 standard. It is found that physical deteriorations and power output degradations. The physical deteriorations in this study can be classified delamination on middle cell, delamination on bus bar, delamination of edge cell and discoloration. For power output degradation, there is no module that was degraded less than 20% of nameplate wattage. There are only 8 of 35 modules (~23%) having power output over 50% of power rating.

Abstract: Renewable energy activities in Thailand are now continuously developed under the deployment of the nationals Alternative Energy Development Plan (AEDP). However, renewable for heat activities require financial instrument or scheme to support the long-run widespread development. This study aims to investigate the appropriate renewable heat incentive (RHI) to encourage the renewable heat projects in Thai market by calculate from the fuel switching concept from various fossil fuels to renewable energy and applying the investment cost, fuel cost, operation and maintenance cost, depreciation along with engineering approaches with expected rate of return from 10 to15%. The replacement from five fossil fuels to 11 types of potential renewable energy, in gasification and direct heating technology, we found that anthracite replaced by RDF require the most support with 5.14 baht per kilogram of RDF. However, in the case of fuel switching to the expensive fuels such as oil and LPG to renewable energy such as biomass, the incentive values are all negative, which means that no support required..

Abstract: This study was for design an economy cooler for increasing energy conversion efficiency of solar panel. Acrylic plastic was used to be material of the cooler and water was a working fluid in the system. The cost to build the cooler model was around 400 Baht. The results found, using cooling system increased energy conversion efficiency and power generation, especially, water flow rate at 200 ccm. At 200 ccm of water flow rate, it increased 0.52% of energy conversion efficiency and 18.01% of power generation. Thus this flow rate was the best condition for increasing energy conversion efficiency. It might due to this flow rate was not slow and was not that fast to absorb heat from solar panel.

Abstract: The effects of carbon black particle dispersed in the electrolyte and used in a modified VRB which was traditionally used of carbon felt as electrode has been removed were studied. The adding of the carbon black particle reduced both activation overpotential and ohmic overpotential especially at low OCV. The functional group on the surface of the carbon black particle helps to increase the rate of reaction which results in the reduction of activation overpotential. When the electrolyte with the carbon black particle dispersed flows into the cell, it is possible that some of carbon particles settle on the surface of current collectors and this effectively increases the surface area of current collectors. Hence, it reduces the ohmic overpotential.

Abstract: In an attempt to improve energy efficiency in classrooms by classroom scheduling, an algorithm was developed to solve the timetabling problem in a Thai university. The algorithm using Tabu Search, unlike all other algorithms for time tabling, aims at reducing classroom energy consumption. The algorithm took into account the number of students in each class, class time, class size, time available for both students enrolling in each class and faculty members in charge of the classes, and energy consumption in each time period of the classroom. The algorithm was used to solve the past timetabling problem of a Thai university over the academic year 2006 to 2012 and the results were compared with those of the trial-and-error traditional timetabling. It was found that the algorithm can be used to significantly lower energy consumption of the classrooms.

Abstract: Fresh cassava roots were used as a raw material for ethanol fermentation. Conventional batch mode (CF), simultaneous saccharification and fermentation (SSF) and simultaneous liquefaction, saccharification and fermentation (SLSF) were investigated with various enzyme systems. The ethanol concentrations obtained in batch fermentations ranged from 8-12 wt%. In addition, vacuum fractionating technique was successfully introduced to simultaneously remove high purity ethanol from fermentation broth in batch mode. The distilled ethanol concentration was approximately 86 wt% whilst its concentration in the bioreactor was kept lower than 2 wt%. As a result, the product inhibition effect to yeast cells was reduced.

Abstract: This research had an aim to study the biogas production from human faece and community waste food using batch fermentation process. In this experiment, there were 5 types of ratio between human faece and community waste food which were 1:0, 2:1, 1:1, 1:2 and 0:1 and the raw material is dilute with water in the ratio 1:4. The biogas digester was clear plastic cylindrical tank of 20 liters, base area of 300 square centimeters and height of 30 centimeters. This experiment was performed to analyze the rate of gas generation before and after the biogas composition fermentation and heating value of biogas. It was found that, in the ratio 2:1 of human faece and community waste food, the rate of biogas generation was the highest. In the ratio of 1:0, the methane gas generation was the highest which the gas methane composition is 67.6% higher than the of other animals manure, the rate of biogas generation was 0.59 m³/kg-VS and the heating value was 24,336 MJ/Nm³.

Abstract: Due to a high ethanol demand, the approach for effective ethanol production is important and has been developed rapidly worldwide. Several agricultural wastes are highly abundant in celluloses and the effective cellulase enzymes do exist widely among microorganisms. Accordingly, the cellulose degradation using microbial cellulase to produce a low-cost substrate for ethanol production has attracted more attention. In this study, the cellulase producing bacterial strain has been isolated from rich straw and identified by 16S rDNA sequence analysis as Acinetobacter sp. KKU44. This strain is able to grow and exhibit the cellulase activity. The optimal temperature for its growth and cellulase production is 37 °C. The optimal temperature of bacterial cellulase activity is 60 °C. The cellulase enzyme from Acinetobacter sp. KKU44 is heat-tolerant enzyme. The bacterial culture of 36 h. showed highest cellulase activity at 120 U/mL when grown in LB medium containing 2% (w/v). The capability of Acinetobacter sp. KKU44 to grow in cellulosic agricultural wastes as a sole carbon source and exhibiting the high cellulase activity at high temperature suggested that this strain could be potentially developed further as a cellulose degrading strain for a production of low-cost substrate used in ethanol production.

Abstract: This work aims to investigate microalgal growth and lipid production from Chlorella sp. on different digester effluents from seafood factory, starch factory and palm oil mill. Results under 32 cultivation days showed that the effluent from seafood factory gave the highest microalgal growth (0.9956±0.2121 g/L) followed by starch factory and palm oil mill (0.8622±0.0391 and 0.2611±0.0444 g/L, respectively). Although higher nitrogen and phosphorus in medium stimulated growth, turbidity of the palm oil mill effluent showed a negative impact. In addition, phosphorus concentration in the medium positively affected the lipid content in cells. The seafood effluent with total phosphorus of 45.24±3.80 mg/L yielded highest lipid content at 26.96±1.58% compared to starch factory (22.10±2.61). The digester effluent from seafood factory was found more suitable for Chlorella sp. cultivation due to the high mass production, oil content and lipid productivity.

Abstract: Mixed plastic wastes recovered from dumpsites may be utilized as densified solid fuel. However, it is commonly known that plastic materials may not bind together under compaction. Corn stover can be used as natural binder in this case. It can improve chemical composition (reducing sulfur and chlorine content) and mechanical strength of the fuel pellet. In this paper, densification of mixed plastic wastes and corn stover was investigated. Compression pressure was conducted at 150 MPa. The pellet size was 8 mm in diameter and 20 mm long. Effects of moisture content (5-20%), types of material, and preheating temperatures (75 and 100°C) on the fuel properties were studied. The pellets from mixed materials were found to have higher calorific value, carbon content and durability index than corn stover pellet.