• Energy Research
• 7. Clean energy close
• 12. Responsible consumption close
• 11. Sustainability close
• University of North Sumatra close

In this work, a compression ignition (CI) engine is tested in dual-fuel mode (Diesel-Raw biogas). The objective is to examine the performance and emission characteristics of the engine when some of the diesel oil is replaced by biogas. The specifications of the CI engine are air cooled single horizontal cylinder, four strokes, and maximum output power of 4.86 kW. It is coupled with a synchronous three phase generator. The load, engine revolution, and biogas flow rate are varied from 600 W to 1500 W, 1000 rpm to 1500 rpm, 0 to 6 L/minute, respectively. The electric power, specific fuel consumption, thermal efficiency, gas emission, and diesel replacement ratio are analyzed. The results show that there is no significant difference of the power resulted by CI run on dual-fuel mode in comparison with pure diesel mode. However, the specific fuel consumption and efficiency decrease significantly as biogas flow rate increases. On the other hand, emission of the engine on dual-fuel mode is better. The main conclusion can be drawn is that CI engine without significant modification can be operated perfectly in dual-fuel mode and diesel oil consumption can be decreased up to 87.5%.

In this work, a compression ignition (CI) engine is tested in dual-fuel mode (Diesel-Raw biogas). The objective is to examine the performance and emission characteristics of the engine when some of the diesel oil is replaced by biogas. The specifications of the CI engine are air cooled single horizontal cylinder, four strokes, and maximum output power of 4.86 kW. It is coupled with a synchronous three phase generator. The load, engine revolution, and biogas flow rate are varied from 600 W to 1500 W, 1000 rpm to 1500 rpm, 0 to 6 L/minute, respectively. The electric power, specific fuel consumption, thermal efficiency, gas emission, and diesel replacement ratio are analyzed. The results show that there is no significant difference of the power resulted by CI run on dual-fuel mode in comparison with pure diesel mode. However, the specific fuel consumption and efficiency decrease significantly as biogas flow rate increases. On the other hand, emission of the engine on dual-fuel mode is better. The main conclusion can be drawn is that CI engine without significant modification can be operated perfectly in dual-fuel mode and diesel oil consumption can be decreased up to 87.5%.

Waste cooking oil (WCO) biodiesel has some disadvantages, such as poor cold flow properties, low oxidation stability, and flash point during storage. These poor physicochemical properties can be improved by different ways, such as the addition of non-edible oil. The aim of this study to analyse physicochemical properties of the biodiesel made by between WCO and Schleichera oleosa (SO). The biodiesel produced with 70:30% of WCO and SO respectively as crude oil, further introducing of different KOH-based catalyst into this oil to obtained the methyl ester. The optimum yield transesterification process are 94% with 60 min. of the reaction time, 1 wt.% KOH, and 12:1 molar ratio the methanol to oil. On the other hand, the Schleichera oleosa blend shows oxidation stability at 6.8 h and 3.3 h for Waste cooking oil methyl ester (WCME). The reduction of cold flow and, on the contrary, the flash point increase were obtained with a 70:30% ratio of WCO and SO. The cold flow properties and flash point of the fuel. Thus, mixed WCO and Schleichera oleosa oil improve the physiochemical properties such as oxidation stability, flash point, and cold flow of biodiesel without the need for synthetic antioxidants.

Waste cooking oil (WCO) biodiesel has some disadvantages, such as poor cold flow properties, low oxidation stability, and flash point during storage. These poor physicochemical properties can be improved by different ways, such as the addition of non-edible oil. The aim of this study to analyse physicochemical properties of the biodiesel made by between WCO and Schleichera oleosa (SO). The biodiesel produced with 70:30% of WCO and SO respectively as crude oil, further introducing of different KOH-based catalyst into this oil to obtained the methyl ester. The optimum yield transesterification process are 94% with 60 min. of the reaction time, 1 wt.% KOH, and 12:1 molar ratio the methanol to oil. On the other hand, the Schleichera oleosa blend shows oxidation stability at 6.8 h and 3.3 h for Waste cooking oil methyl ester (WCME). The reduction of cold flow and, on the contrary, the flash point increase were obtained with a 70:30% ratio of WCO and SO. The cold flow properties and flash point of the fuel. Thus, mixed WCO and Schleichera oleosa oil improve the physiochemical properties such as oxidation stability, flash point, and cold flow of biodiesel without the need for synthetic antioxidants.

Today, the use of wind energy by wind turbines has grown significantly, and this development is due to the production of required energy and tourism attraction of wind turbines. But according to the standard technologies used in this industry, the operating costs are very high. For this reason, before the construction of wind farms, potential measurements should be done along with economic analysis. Therefore, in this research, a statistical analysis of wind farms has been done. In the statistical analysis, Weibull and Rayleigh distribution functions were used to predict the wind speed of the studied area. MATLAB software is used to model prediction functions. Among the important results of wind speed prediction by the Weibull distribution function, it can be mentioned that the wind speed is variable between 0.6 and 7 m/s in the studied area. The total power density and wind energy in the 10 years are equivalent to 28 W/m2 and 810/0534 kWh/m2 at the height of 10 m calculated.

Today, the use of wind energy by wind turbines has grown significantly, and this development is due to the production of required energy and tourism attraction of wind turbines. But according to the standard technologies used in this industry, the operating costs are very high. For this reason, before the construction of wind farms, potential measurements should be done along with economic analysis. Therefore, in this research, a statistical analysis of wind farms has been done. In the statistical analysis, Weibull and Rayleigh distribution functions were used to predict the wind speed of the studied area. MATLAB software is used to model prediction functions. Among the important results of wind speed prediction by the Weibull distribution function, it can be mentioned that the wind speed is variable between 0.6 and 7 m/s in the studied area. The total power density and wind energy in the 10 years are equivalent to 28 W/m2 and 810/0534 kWh/m2 at the height of 10 m calculated.

Palm oil palm is one of the solid waste produced by oil palm plantations every harvest. Chemical analysis of palm oil palm oil pellets showed that there are components of cellulose, hemiscellulose, and lignin that show that palm oil pellets have the opportunity to be further processed into useful and economically valuable products. Palm waste contains cellulose by 34.89%, hemiscellulose by 27.14%, and lignin by 19.87%. The analysis conducted on raw materials includes the analysis of water content and cellulose levels of palm oil palm oil. 46.6% and cellulose levels of 29.2%. In this study quantitative analysis was conducted in the form of cellulose conversion and oxalic acid yield. The largest cellulose conversion was obtained at the use of 70% nitric acid concentration and 80 minutes reaction time of 58.56%.

Palm oil palm is one of the solid waste produced by oil palm plantations every harvest. Chemical analysis of palm oil palm oil pellets showed that there are components of cellulose, hemiscellulose, and lignin that show that palm oil pellets have the opportunity to be further processed into useful and economically valuable products. Palm waste contains cellulose by 34.89%, hemiscellulose by 27.14%, and lignin by 19.87%. The analysis conducted on raw materials includes the analysis of water content and cellulose levels of palm oil palm oil. 46.6% and cellulose levels of 29.2%. In this study quantitative analysis was conducted in the form of cellulose conversion and oxalic acid yield. The largest cellulose conversion was obtained at the use of 70% nitric acid concentration and 80 minutes reaction time of 58.56%.

AbstractIn the present paper a study on the performance of clothes drying cabinet by utilizing waste heat from a split-type residential air-conditioner (RAC) has been carried out. A drying cabinet with a volume of 1m3 has been designed and fabricated. The waste heat from the condenser of the RAC with power of 800W was utilized as a heat source. In the experiments, the RAC was operated to keep a conditioned space at 20°C. The clothes dried made of pure cotton with initial weight varied 3.05kg, 5.25kg, 6.21kg, 8.22kg, and 10.22kg. Two different inlets, single inlet and multi-inlets, has been tested. The results show that the drying time varies from 80 to 410min. For single inlet the averaged drying time, optimum initial weight, optimum drying rate and optimum SMER was 242min, 6.21kg, 0.868kg/h, and 2.345kg/kWh. On the other hand, the drying chamber with multi-inlets the averaged drying time, optimum initial weight, optimum drying rate and optimum SMER was 222min, 8.22kg, 0.922kg/h, and 2.492kg/kWh. Thus, the present drying cabinet should be operated with multi-inlets and the initial weight varies from 6 to 8kg.