Chantana Punlek

Improving Mechanical Properties of Autoclaved Aerated Concrete by Sugar Sediment

The comparison of microstructure and mechanical properties between the autoclaved aerated concrete (AAC) and the autoclaved aerated concrete consist of sugar sediment (AAC-SS) was investigated in this work. The microstructure of AAC and AAC-SS was analyzed by the scanning electron microscopy (SEM). The mechanical properties of AAC and AAC-SS were focused on the compressive strength, the density, the water absorption and the flexural strength. To comfirm the tobermorite phase, the phase formation of the samples was tested using X-ray diffraction (XRD). It was found that the microstructure of AAC and AAC-SS surface was the finer needle-like crystalline morphology. The compressive strength (5.9 N/mm2) and flexural strength (1.82 N/mm2) of AAC-SS were higher than that of the AAC (5.0 N/mm2 and 1.64 N/mm2). While, the value of density (0.60 g/cm3) and humidity (23.59%) of AAC-SS had little less than that of the AAC (0.61 g/cm3 and 24.11%). The increasing of the tobermorite phase, which was added by the sugar sediment, had affected to the improvement of the mechanical properties. The specimens of both AAC and AAC-SS were claimed in quality class of 4, which based on the Thai Industrial Standard 1505-1998.

Thermoelectric generator for the recovery of energy from the low grade heat sources in sugar industry

Received May 21, 2018 Revised Aug 30, 2018 Accepted Sep 13, 2018 This paper presents a novel Stator Current based Model Reference Adaptive System (SC_MRAS) speed observer for high-performance Six Phases Induction Motor (SPIM) drives using linear neural network. The article aim is intended to improve performance of an SC_MRAS observer, which were presented in the literature. In this proposed scheme, the measured stator current components are used as the reference model of the MRAS observer to avoid the use of a pure integrator and reduce the influence of motor parameter variation. The adaptive model uses a two-layer Neural Network (NN) to estimate the stator current, which has been trained online by means of a Least Squares (LS) algorithm instead of uses a nonlinear Back Propagation Network (BPN) algorithm to reduce the complexity and computational burden, it also help to improve some disadvantages cause by the inherent nonlinearity of the BPN algorithm as local minima, two heuristically chosen parameters, initialization, and convergence problems, paralysis of the neural network. The adaptive model of the proposed scheme is employed in prediction mode, not in simulation mode as is usually the case in the literature, this made the proposed observer operate better accuracy and stability. In the proposed observer, stator and rotor resistance values are estimated online, these values thereafter were updated for the current observer and rotor flux identifier to enhance the accuracy, robustness and insensitivity to parameters variation for the proposed observer. The proposed LS SC_MRAS observer has been verified thought the simulation and compared with the BPN MRAS observer. The simulation results have proven that the speed is estimated a consequent quicker convergence, do not need the estimated speed filter, lower estimation errors both in transient and steady state operation, better behavior in low and zero speed operation. Keyword:Received Jun 7, 2018 Revised Jul 8, 2018 Accepted Sep 13, 2018 Experiments confirmed that Transformerless Inverters (TIs) deliver more reliability and higher energy efficiency. Nonetheless, one of the shortcomings of TIs is the leakage current that occurs between the photovoltaic (PV) string terminals and the ground. Such a drawback is justified by the non-galvanic isolation caused by the transformer being omitted. As such, this study is intended to develop a novel TI inverter topology for solar PV systems. The latter is meant to remove the leakage current and enhance the operating system of the entire PV conversion as well. Added to its null zero-crossing distortion and capability regarding energy efficiency, the developed TI, being validated by simulation and experiment, eradicated the leakage current. Keyword:Now a day’s renewable energy sources became an interesting area of research of which fuel cells are emerged as an alternative source for producing electricity to meet the energy crisis. This led to a research on power conditioning systems through which fuel cell is interfaced to the utility. Of the different converter topologies Isolated full bridge boost converter (IFBC) topology is most suitable for fuel cell applications. In this paper a Predictive Switching Modulator (PSM) Control is proposed for the converter topology and its performance is compared with Linear Peak Current Mode control (LPCM), Non-Linear Carrier Control (NLC).Received May 2, 2018 Revised Aug 23, 2018 Accepted Sep 14, 2018 Recently of the main topic of research is the sensorless vector control of induction motor drive, In this paper presents the predictive model reference adaptive system (PMRAS) rotor speed observer, This observer developed from the classical MRAS rotor flux scheme associated with predictive adaptation mechanism designed from the Finite Control Set Model Predictive Control (FCS–MPC) by using a search optimization algorithm for calculate the rotor position which guarantee a minimum speed tuning error signal at each sampling period. The effectiveness of the proposed observer proved with the simulation results, show high dynamic performance speed and position observed in sensorless vector control process at low and zero speed as well robustness against motor parameter variation with different loading conditions. Keyword:

The optimization of hybrid air ventilation system combined with silica gel and thermoelectric using monitoring control

Received May 21, 2018 Revised Aug 30, 2018 Accepted Sep 13, 2018 This paper presents a novel Stator Current based Model Reference Adaptive System (SC_MRAS) speed observer for high-performance Six Phases Induction Motor (SPIM) drives using linear neural network. The article aim is intended to improve performance of an SC_MRAS observer, which were presented in the literature. In this proposed scheme, the measured stator current components are used as the reference model of the MRAS observer to avoid the use of a pure integrator and reduce the influence of motor parameter variation. The adaptive model uses a two-layer Neural Network (NN) to estimate the stator current, which has been trained online by means of a Least Squares (LS) algorithm instead of uses a nonlinear Back Propagation Network (BPN) algorithm to reduce the complexity and computational burden, it also help to improve some disadvantages cause by the inherent nonlinearity of the BPN algorithm as local minima, two heuristically chosen parameters, initialization, and convergence problems, paralysis of the neural network. The adaptive model of the proposed scheme is employed in prediction mode, not in simulation mode as is usually the case in the literature, this made the proposed observer operate better accuracy and stability. In the proposed observer, stator and rotor resistance values are estimated online, these values thereafter were updated for the current observer and rotor flux identifier to enhance the accuracy, robustness and insensitivity to parameters variation for the proposed observer. The proposed LS SC_MRAS observer has been verified thought the simulation and compared with the BPN MRAS observer. The simulation results have proven that the speed is estimated a consequent quicker convergence, do not need the estimated speed filter, lower estimation errors both in transient and steady state operation, better behavior in low and zero speed operation. Keyword:Received Jun 7, 2018 Revised Jul 8, 2018 Accepted Sep 13, 2018 Experiments confirmed that Transformerless Inverters (TIs) deliver more reliability and higher energy efficiency. Nonetheless, one of the shortcomings of TIs is the leakage current that occurs between the photovoltaic (PV) string terminals and the ground. Such a drawback is justified by the non-galvanic isolation caused by the transformer being omitted. As such, this study is intended to develop a novel TI inverter topology for solar PV systems. The latter is meant to remove the leakage current and enhance the operating system of the entire PV conversion as well. Added to its null zero-crossing distortion and capability regarding energy efficiency, the developed TI, being validated by simulation and experiment, eradicated the leakage current. Keyword:Now a day’s renewable energy sources became an interesting area of research of which fuel cells are emerged as an alternative source for producing electricity to meet the energy crisis. This led to a research on power conditioning systems through which fuel cell is interfaced to the utility. Of the different converter topologies Isolated full bridge boost converter (IFBC) topology is most suitable for fuel cell applications. In this paper a Predictive Switching Modulator (PSM) Control is proposed for the converter topology and its performance is compared with Linear Peak Current Mode control (LPCM), Non-Linear Carrier Control (NLC).Received May 2, 2018 Revised Aug 23, 2018 Accepted Sep 14, 2018 Recently of the main topic of research is the sensorless vector control of induction motor drive, In this paper presents the predictive model reference adaptive system (PMRAS) rotor speed observer, This observer developed from the classical MRAS rotor flux scheme associated with predictive adaptation mechanism designed from the Finite Control Set Model Predictive Control (FCS–MPC) by using a search optimization algorithm for calculate the rotor position which guarantee a minimum speed tuning error signal at each sampling period. The effectiveness of the proposed observer proved with the simulation results, show high dynamic performance speed and position observed in sensorless vector control process at low and zero speed as well robustness against motor parameter variation with different loading conditions. Keyword:

Utilization of Sugar Sediment Waste for a Low Cost Lightweight Concrete Development with Environmental Impact Reduction

Waste sugar sediment was included in the mix of lightweight concrete. The optimum mix that we identified was 10% by weight replacement of lime by sugar sediment. The resultant product exhibited the highest compressive strength of approximately 5.5 N/mm2, and demonstrated that a substantial proportion of the 872 million kgs of waste sugar sediment produced in Thailand per year could be diverted from landfills, providing substantial economic and environmental benefits. Our analysis indicates that about 13 million kgs of lime could be replaced by an equal amount of sugar sediment, 13 million kgs, per year, if the improved composition of lightweight autoclaved aerated concrete is adopted by the construction industry on a wide scale. As the cost of lime is about 2 Baht per kg, and sugar sediment is essentially a free input, an estimated 26,000,000 Baht per year savings is achievable. The economic, environmental and health impacts of reducing this industrial waste going into landfill areas by 13 million kgs per year must also be seen as substantial.

Experimental Investigation of Heat Transfer of Refrigerant Fluid Pulsating Heat Pipe

Heat transfer performances of a pulsating heat pipe (PHP) having internal and external diameter with 4.5 mm and 6 mm with various contents of refrigerant are experimentally investigated. The working fluid as R404A refrigerant was filled in the volume ratios from 0% to 80% and the heat input was controlled in the range from 10 W to 80 W. Obtained results exhibited the ability of R404A refrigerant can enhance the thermal performance in steady state condition. The average temperature difference of the evaporating section and condensing section in the 80% filling volume ratio decreased from 9.5 °C to 2.5 °C when the heating power increase from 10 W to 80 W. The thermal resistance of evaporator and condenser decreased with an increase of the heat input as well. For other filling volume ratios, the trend of temperature difference and thermal resistance was similar to that of the 80% volume filling ratio. Considering the same heat input, the highest heat transfer performance was found at the 80% volume filling ratio. Refrigerant with a relatively low dynamic consistency can lead to relatively high velocity in the PHP that can reduce the temperature difference between the evaporating section and condensing section.

Coefficient of Performance of Thermoelectric Cooling on Nanofluids

This paper reports on experimental comparisons of coefficient of performance (COP) of a thermoelectric coolingsystem which cooled the hot side of the TEC by water (wc), ethylene glycol (egc) and nanofluids (nfc) The nanofluids is composed of ethylene glycol with silver nano(35 nm).The TEC was composed of the TE cooling modules, heat exchanger, and the air cooled heat sink at the cold side of the TE modules.Experiments were conducted with various current input 1 - 4.5 A to find out the optimum current input condition. To consideration of cooling capacity and COP of system was measured the hot and cold side temperature of TEC. Results shown that, the cooling capacity was increased with current input. The maximum cooling capacity of nfc, egc and wc are about 72, 62 and 41 W, respectively. Considered with highest COP found that the optimum current input is approximately 2.5 A. The maximum COP of nfc, egc and wc are about 2.01, 1.7 and 1.12, respectively. Therefore, the proposed TEC-nfc concept is expected to contribute to wider applications of the TE cooling system.

Feasibility of Refuse Derived Fuel 5 Composed of the Mechanical Biological Waste Treatment and Crude Oil Sludge

The main focus of this paper is concerned with the production and properties of refuse derived fuel 5 (RDF-5) for use in energy from waste technologies. The analysis was performed using feedstocks made up of residues from a range of mechanical biological treatment (MBT) plants and crude oil sludge. The RDF-5 was composed of crude oil sludge and mechanical biological waste treatment (MBWT). The ratios of MBWT to crude oil sludge were 5:95, 10:90, 15:85 and 20:80 respectively. The physical and thermal characteristics of RDF-5 were examined. This was further investigated in the context of the parameters required during production and the properties of RDF-5. RDF-5 was produced using a screw compactor. Analysis of the optimal mixing ratios between the crude oil sludge and MBWT were undertaken by testing the thermal value based on ASTM D 240 moisture contents was based on ASTM D 3173, ash was based on ASTM D 3174, and density was based on ASTM E 75 respectively. The results showed that the optimal ratios of MBWT to crude oil sludge were 15:85 and 20:80 have feasibility to produce the RDF-5. Because of the ratios of 15:85 and 20:80 have a high value 10,831 kcal/kg and 11,260 kcal/kg, the percentages of moisture were 2.73% and 5.93% and the density values were 750 kg/m3 and 806 kg/m3 respectively (RDF-5 has a high heating value (HHV > 5,000 kcal/kg), with the percentage of moisture content not exceeding 10 percent and the density value (D 600 kg/m3) according to production of solid fuels standards). The ash values were 5.10% and 4.74% respectively. Comparing the energy production costs between RDF-5 and other fuels used in Thailand we found that the production costs of RDF-5 were 0.014 /MJ and 0.013 /MJ which are comparable to that of paddy husk and much cheaper than those of fuel lignite and bituminous. This preliminary evaluation reveals that the recovery of energy through RDF-5 production from MBWT with crude oil sludge is cost attractive and it should be considered as a feasible option for utilizing energy from MBWT with crude oil sludge.

Hybrid Producer Gas Using Biomass Combined Thermoelectric

The hybrid Biomass gasification-Thermoelectric system (BG-TES) is full renewable energy system. Hybrid system was integrated with biomass gasifier and thermoelectric power generation. To illustrate, the rice husk was used to be the alternative fuel in a biomass gasifier and TE generated electric energy for air flow into gasification system. BG-TE system was developed and analyzed in variations of air flow rates in order to show the efficiency of the system. In this study, the different air flow rates were tested of 2.03x10-3, 2.15x10-3 and 2.44x10-3 m3/s with using rice husk 1.2 kg per once operated. The optimum operation condition was considered by comparing between thermal efficiency and air flow rates of BG-TES. The result has been shown that 2.435 x 10-3 m3/s is optimum flow rate for gasification system. It could be generating maximum producer gas which system was operated about 40 minute. Biomass gasification system had 19.43% of thermal efficiency Whereas the conversion efficiency of the TE power generator was around 2.42%. According to the biomass energy, the rice husk is not only the alternative fuel but it is also abundant in remote area. Therefore, the rice husk is one of the promising fuels that can be used to replace the LPG in the lacking power area. The rice husk at one operation was replaced LPG about 0.2 kgLPG. In conclusion, BG-TES using rich husk is the alternative system that can be suitable for lacking power area.

Application Using Sugar Sediment to Enhance Mechanical Properties of Autoclaved Aerated Concrete

The effect of fine sand replacement by the sugar sediment (0, 10, 15, 20, 25, 30, 35, 40, 45 and 50 weight %) on the physical and mechanical properties was studied in this work. The physical and mechanical properties of AAC with various contents of sugar sediment were focused on the density, the humidity, the water absorption, the open porosity volume, the compressive strength and the flexural strength. The average density, humidity, water absorption, volume of open porosity, compressive strength and flexural strength of all compositions had the value in the range of 0.57-0.61 g/cm3, 23.0-26.7 %, 0.38-0.40 g/cm3, 259-287 cm3, 4.4-5.9 N/mm2 and 1.03-1.82 N/mm2, respectively. The maximum compressive strength and flexural strength were found from the AAC sample with the sugar sediment content of 30%, which were 5.9 N/mm2 and 18.14 N/mm2. Moreover, these samples also exhibited the density (0.60 g/cm3), the humidity (23.6%), the water absorption (0.39 g/cm3) and the volume of open porosity (272 cm3) were claimed in quality class of 4. The specimens of AAC with the sugar sediment content of 0-40% were claimed in quality class of 4, which based on the Thai Industrial Standard 1505-1998.

Thermal Resistance by Phase Change Materials of the Double Roof System

This research studies about the possibility of Phase change materials for development with the double roof system which uses the Radiant barrier to reduce the heat into the house and to reduce load of the air conditioner. The experiment was divided into 4 patterns. The Radiant barrier and the Phase change materials are on top of the air passage (model 1). The Phase change materials and the Radiant barrier are on top of the air passage (model 2). The Radiant barrier is under the roof and the Phase change materials is under the air passage is (model 3). The Radiant barrier is under the air passage and the Phase change materials is under the roof (model 4). By building the test room sizes 90x90 cm2 and the air passage sizes 10 cm. The heat source from the heat generator in temperature is 45, 50, 60. The results revealed that if the Radiant barrier is under the roof and the Phase change materials is under the air passage, temperature will tend to decrease by the heat transmission into the house decrease about 3-5 in the experiment. The above-mentioned decrease of the temperature, the calculation of the thermal energy per unit area in (model 3) can decrease the most quantity of heat flux more than the other patterns by average at 19.66, 22.5 and 29.14 W/m2 respectively. From the experiment was found that (model 3) has the appropriate position for development more than the other patterns.