PENGEMBANGAN METODE SIMULASI SISTEM PENGKONDISIAN UDARA ENERGI SURYA

In this research, a simulation method has been developed for designing a solar air conditioner and predicting its perfomances. This simulation based on solar irradiation data, solar collector performance data, LiBr-H2O absorption chiller single effect performance data, Phase Change Material (PCM) data as its inputs. Napthalene is used for HTTS and acetic acid is used for TTS. Energy balance, mass balance, and characteristic equations of each component are used in the solar air conditioning simulation. Validation of the developed simulation model was done with experiment data for solar air conditioning system with HTTS and LTTS without auxiliary heater. Generally, the tendency of the simulation and experiment results are similar. The application of HTTS and LTTS make the system can be operated more in 100 minutes

Experimental Study on Flow Characters of Salt Hydrate Slurry in Phase Change Temperature Range

One of the efforts in minimizing energy consumption chiller type air conditioning system is the use of phase changing material in secondary refrigerant. Secondary refrigerant functions to obtain heat from the air to cool a room and to release heat in chiller evaporator. Based on working temperature of secondary refrigerant, the fluid can flow in liquid form, and can also be in fluid solid form or slurry at the temperature of its phase change. This research studies the effect of temperature toward flow characteristics, with the parameter analyzed being the pressure decrease and friction coefficient. Besides that, in order to support data analysis, it was initiated by viscosity testing, density and concentration of solid mass. Data taken were viscosity, density, solid mass concentrate, and pressure difference found in copper pipe. Data were taken for several fluid temperatures, and at pressure decrease was added by variation of flow speed. Hydrate salt tested were CaCl2 and Na2HPO4. Viscosity and density increased with the decrease in temperature. The formation of solid particles within phase change temperature range also gave an impact on the increase in the value of viscosity and density. Pressure drop increased when using hydrate salt fluid. The use of CaCl2 solution resulted in the highest pressure decrease. This salt hydrate has far higher viscosity and density compared to water. This has an effect toward an increase in pressure drop. This increase started to be significant in the phase change temperature area in which solid particle started to form. The same thing happened in the friction coefficient value

SIFAT MAMPU NYALA DAN MASSA OPTIMUM REFRIGERAN CAMPURAN R-290/R-22 SEBAGAI ALTERNATIF PENGGANTI R-22

The limited application of ozone depleting substance (ODS) such as CFC and HCFC refrigerants has encourage researchers to find a new alternative refrigerant. Hydrocarbon refrigerant such as R-290 (propane) has been widely used because it is environmentally friendly, save energy, and drop-in substitute. However, hydrocarbon refrigerants are flammable and categorized as A3 class refrigerant, so that the application of the refrigerants are limited by safety standard. In this research, an effort to lower the flammability of R-290 has been carried out. Series of flammability test have been done to proof that the flammability of R-290 is reduced by mixing it with R-22. Mixture of R-290/R-22 at molar fraction 0.4/0.6, 0.5/0.5, 0.59/0.41 has Lower Flammability Limit (LFL) above 3.5%, so that it can be classified as A2 class refrigerant. The optimum refrigerant charges of the refrigerant mixtures that give the highest COP have also been investigated. The results show that the optimum refrigerant charge of the mixture is lower than R-22 but higher than pure R-290. The system COP of R-290/R-22 mixture is higher than that of R-22 but lower than R- 290 system

KAJI EKSPERIMEN OPTIMASI KOEFISIEN DAYA SKEA JENIS POROS DATAR DENGAN SUDU GABUNGAN SILINDER BERPUTAR DAN ROTOR SAVONIUS

Horizontal Axis Wind Energy Conversion System (HAWECS) is more efficient than other Wind Energy Conversion Systems at the same condition [2,3]. Rotating cylindrical blade is taken as the substitute alternative to the airfoil blade considering that presence of lift force and its simple manufacturing production. The lift force generated by the rotating cylinder is known as the Magnus Effect [1,7,9]. The savonius rotor in this research is employed to propel the cylinder. This research conducted an experiment to optimize the energy conversion of a HAWECS which its blades consist of the combination of cylinder and savonius rotor. Two kind of blades were used in this experiment, i.e.blade with L/D (ratio of the length and diameter of cylinder) equals to 3 and 4. Three variations of wind velocities were used, i.e. 8.5 m/s, 9.7 m/s, and 10.2 m/s. Experimental results present that the blade with L/D ratio = 4 give more efficient than the L/D = 3, and the increase of power was reached if the wind velocity increases

Potensi Pemanfaatan Serat Selulosa sebagai Material Bahan Baku dalam Sintesis Filter Udara Non-Woven Sesuai Standar TAPPI T 205

Industry 4.0 era materials used by entrepreneurs should be recycled, environmentally friendly, renewable with less chemical content. Indonesia as a tropical country has a large land area with the potential to produce the largest natural fiber in the world. One opportunity that can be applied to the utilization of natural fibers in air filters that currently use dominant materials is synthetic fibers. natural fiber has the advantage because it does not contain toxic chemicals, local raw materials, and is easily produced. This research will analyze the mechanical and morphological characteristics of biological fibers that have great potential as pre-filter raw material. Analysis of mechanical properties through tensile strength testing for single fibers and morphological analysis through scanning electron microscopy (SEM). Tensile testing was the results are; palm oil has a tensile strength of 620 MPa; 998 MPa and 213 MPa flax coconut fiber. For the morphological test results from SEM analysis for ramie fiber, it looks solid without fiber holes; The fibers appear to be many small fibers bound to one another while coir fibers have many pore holes in one observed fiber

Metodologi Perhitungan Koefisien Perpindahan Panas Konveksi Paksa Fluida Organik Propana pada Kondisi Superkritik

Penelitian tentang siklus Rankine organik superkritis mulai giat dilakukan sebagai salah satu usaha untuk meningkatkan efisiensi termal dari siklus Rankine organik. Pada kondisi superkritik, sifat-sifat termodinamika dan fisika dari fluida organik berubah dengan sangat drastis disekitar titik kritisnya. Sehingga perhitungan koefisien perpindahan panas konveksi paksa tidak dapat lagi dilakukan dengan asumsi sifat-sifat fluida konstan. Dalam penelitian ini diusulkan sebuah metodologi untuk menghitung nilai koefisien perpindahan panas pada kondisi superkritis. Propana digunakan sebagai fluida organiknya. Tipe alat pemindah panas yang dipakai adalah jenis pipa ganda aliran berlawanan arah dan perhitungan bilangan Nusselt menggunakan korelasi Dittus-Boetler dan Gnielinski. Hasil perhitungan koefisien perpindahan panas dengan menggunakan metodologi ini dapat digunakan untuk menghitung luas daerah perpindahan panas dari alat pemindah panas tipe double pipe counter flow. Selanjutnya hasil perhitungan ini perlu dibandingkan dengan nilai koefisien perpindahan panas yang diperoleh dari hasil eksperimen

Thermal Characteristics Evaluation of Vegetables Oil to be Used as Phase Change Material in Air Conditioning System

In a typical commercial building, air conditioning system consumes around 60% of building’s electricity. By looking at that number, it is clear that effort to suppress building energy consumption should be directed to air conditioning system. Recently, phase change substances, such as ice slurry, receive broad attention since the substances has ability to save energy in hydronic cooling system. Previous experiments by author showed that certain phase change material, i.e. trimethylolethane trihydrate, is able to save energy of a chiller. However, in Indonesia, the material is quite expensive. In this research, applicability of some lower-price materials, i.e. mixture of vegetables oil and biodiesel, as phase change material in secondary refrigerant were evaluated. Some thermal characteristics, such as freezing and melting temperatures, and also latent heat of the oils are explained in this paper