Muhammad Idrus Alhamid

Simulation and Optimization of Solar Thermal Cooling System in Manufacturing Research Center Building to Reduce Operational Cost Using Software EnergyPlus and GenOpt

Solar Thermal Cooling System with its absorption cycle is expected to replace the conventional air conditioning system with vapor compression cycle because it is more efficient in terms of cost and energy. However, due to the heat of the sun is not always stable, the system needs to be equipped with a backup energy source, one of which is CNG. In the Manufacturing Research Center building, the lack of facilities that support availability of CNG causes large operational cost. Therefore, optimization efforts with the aim to reduce operational cost are needed. Simulation and optimization performed with EnergyPlus and GenOpt. The conclusion is that the installation of 187.5 kW electric tankless water heater is able to reduce total operational cost by 34.65% compared to system that uses combination of solar thermal and CNG and 49.69% compared with system that uses only CNG.

Adsorption Isotherms of Hydrogen on Granular Activated Carbon Derived From Coal and Derived From Coconut Shell

ABSTRACT The development of adsorption-based storage systems requires a basic understanding of the isotherms over a wide range of pressure and temperatures for various types of adsorbents. This research is to generate experimental isothermal adsorption data for the adsorption of hydrogen gas on activated carbon. The adsorption apparatus is based on a volumetric method, and the experiments were conducted at temperatures ranging from 273 to 308 K and pressures up to 4 MPa. Two types of activated carbon, (i) a granular coal from Indonesia and (ii) a coconut-shell activated carbon that is produced in the laboratory, were used in the experiments. The experimental data are analyzed using the Langmuir, Toth, and Langmuir–Freundlich isotherm models.

High-Pressure Adsorption Isotherms of Carbon Dioxide and Methane on Activated Carbon From Low-Grade Coal of Indonesia

ABSTRACT Adsorption isotherms data of methane and carbon dioxide gases on the activated carbons were measured experimentally using a volumetric method with pressure and temperatures ranging from 0 to 3.5 MPa and 27 to 65°C, respectively. Two types of activated carbons, namely, (1) Kalimantan Timur type activated carbon, which is lab-produced from Indonesian low-grade coal and (2) a commercial (Carbotech) activated carbon were used. The adsorption isotherms obtained were found to belong to type 1 of the International Union of Pure and Applied Chemistry classification. The adsorption uptakes for both carbon dioxide and methane on commercial activated carbon are higher than for the Kalimantan Timur activated carbon. This is due to higher Brunauer–Emmet–Teller surface area and pore volume of the former. Langmuir and Tóth isotherm models are correlated to predict the experimental data with acceptable accuracy.

Characteristics of Two-Phase Flow Pressure Drop of Propane in Horizontal Circular Small Tube

This study experimentally investigated two-phase flow pressure drop of propane as refrigerant in horizontal small tube. Inner diameter and length of the tube were 7.6 mm and 1.07 m, respectively. In order to get pressure drop data, the experiment was conducted in various conditions of 10 to 25 kW m-2 heat flux, 200 to 628 kg m-2 s-1 mass flux, and 4.0 to 11.7°C saturation temperature. This study clearly showed the effect of heat flux, mass flux, and saturation temperature on the pressure drop of propane. This study also investigated which fluid properties gave higher effect on the frictional pressure drop due to its change over the process based on the recent experiment data. The existing pressure drop correlations were evaluated against the experimental result.

Pressure Drop of Two-Phase Flow Boiling with R-22 and R-290 in 7.6 mm Diameter Tube

The characteristics of two-phase flow boiling of R-290 are required for replacing R-22 that has been phased-out. The present study focuses on experimental pressure drop for R-22 and R-290. The experiment was run with heat flux of 5.09 kW/m2 to 19.03 kW/m2, mass flux of 114.91 kg/m2s to 751.74 kg/m2s and saturation temperature of 4.77°C to 18.12°C. The present result showed that pressure drop was affected by heat flux, mass flux and saturation temperature. Lower mass flux, heat flux and saturation temperature results in lower pressure drop. The pressure drop of R-290 is lower than that of R-22. Among the existing pressure drop prediction methods, Lokhart-Martinelli (1949) gives the best prediction for the present pressure drop data.

Cost Estimation Study for the Effect of Biofouling on Engine Cooling System Performance with an 8000 BHP Vessel

Every engine needs a cooling system in order to maintain the performance of engine. In this study the cooling system is applied in naval ship with the exchange of freshwater and seawater. Since the seawater contains biological fouling, then it is scaled in the heat exchanger so that the performance of heat exchanger is decreasing from time to time. This makes the heat transfer rate in cooler is less efficient so that to maintain the BHP of the engine it needs to consume more fuel. The result shows that the effect could incur a loss of about USD 463,852.8/month. This condition makes the importance of cooling system maintenance in order to keep the temperature of the naval ship engine and to minimize the additional fuel cost. For cooling system itself, to keep the cooler in a good condition, it needs to clean the cooler for every 720 hours, or once a month.

Effect of Hot Air Reservoir and Insulator Tray in the Development of Vacuum Freeze Drying

The Objective of this work is to know effect of inserting hot air from reservoir to the process of vacuum freeze drying. Tentacle of jelly fish as sample with constant weight 50 g and placed at insulator and teflon container which isolated, the samples were freeze dried with condition at experiment varying between inserting and without inserting hot air at temperature 27°C and also heating from heat loss condenser. The result of experiment shows that while inserting hot air into vacuum freeze drying make pressure rise in until pressure reach 40 mbar. And this phenomena make material evaporation and this event cant be done in vacuum freeze drying. And when without hot air reservoir the pressure can reach 3.5 mbar and the subimation can be done in this process. Vacuum freeze drying process without hot air reservoir need time 12.5 hours and for vacuum freeze drying with hot air reservoir need time 11 hour to drying 50 g of jelly fish tentacle. For process with insulator tray the material can be done in 22,7 hour with internal freezing. From this experiment can be concluded that for vacuum freeze drying with inserting hot air need more ability of vacuum pump specially in flowrate and ultimate vacuum to keep the chamber pressure below triple point condition.

Identification and Control Design of Fuzzy Takagi-Sugeno Model for Pressure Process Rig

The design of an intelligent controller based on fuzzy TS model for a pressure process rig is presented. The proposed controller consists of a fuzzy TS model, a feedback fuzzy TS model, and a low pass filter combined in an internal model control structure. The identification of the fuzzy TS model uses fuzzy clustering technique to mimic the nonlinearity characteristic of the process. Instead of least-squares algorithm, the instrumental variable method is used to estimate the consequent parameters of the fuzzy TS model in order to avoid inconsistency problem. The identified model is validated with the performance indicators variance-accounted-for and root mean square. By using the technique of inverse fuzzy model analytically, the feedback fuzzy controller is designed based on the identified fuzzy TS model. The performance of the proposed controller is verified through experiments at various operating points.