HEAT TRANSFER ENHANCEMENT AND PRESSURE DROP OF GROOVED ANNULUS OF DOUBLE PIPE HEAT EXCHANGER

This investigation was performed to experimentally investigate the enhancement of heat transfer and the friction of an annulus in a double pipe heat exchanger system with rectangular grooves in the turbulent flow regime. The shell is made of acrylic and its diameter is 28 mm. The tube is made of aluminium and its diameter is 20 mm. Grooves were incised in the annulus room with a circumferential pattern, with a groove space of 2 mm, a distance between the grooves of 8mm and a groove height of 0.3 mm. The experiments consist of temperature and pressure measurement and a flow visualization. Throughout the investigation, the cold fluid flowed in the annulus room. The Reynold number of cold fluid varied from about 31981 to 43601 in a counter flow condition. The volume flow rate of hot fluid remains constant with Reynold number about 30904. Result showed the effect of grooves, which are applied in the annulus room. The grooves induce the pressure drop, the pressure drop in the grooved annulus was greater by about 15.88% to 16.72% than the one in the smooth annulus. The total heat transfer enhancement is of 1.09–1.11. Moreover, the use of grooves in the annulus of the heat exchanger not only increase the heat transfer process, but also increase the pressure drop, which is related to the friction factor

PENGARUH SUPERHEAT TERHADAP PERFORMANSI SISTEM AIR CONDITIONING JENIS WATER CHILLER

Kebutuhan akan AC yang dapat memberikan kenyamanan dalam suatu ruangan adalah sangat vital. AC untuk kapasitas besar baik penggunaan dalam industri, supermarket maupun perhotelan, biasanya digunakan sistem AC sentral jenis water chiller. Baik buruknya kinerja suatu sistem pendingin ditentukan oleh besar-kecilnya nilai performansi (COP). Semakin besar nilai COP menyatakan kinerja sistem pendingin semakin baik. Salah satu yang dapat mempengaruhi nilai COP adalah alat ekspansi. Alat ekspansi yang digunakan untuk sistem AC sentral jenis water chiller adalah Thermostatic Expantion Valve (TXV). Akibat penyetelan variasi sudut putar sekrup TXV dari standar produk mempengaruhi superheat sistem pendingin. Besar kecilnya superheat mempengaruhi COP sistem pendingin. Hasil eksperimen menunjukkan bahwa penyetelan sudut putar sekrup TXV searah maupun berlawanan dengan jarum jam dari standar produk tidak memberikan pengaruh perubahan nilai COP yang lebih baik

Karakteristik temperatur fluida dingin pada grooved double pipe heat exchanger

Heat exchangers have widespread applications in many industrials process. There are many kind of heat exchanger. One of the simply heat exchanger is double pipe heat exchanger. The need for lightweight and enhancing the heat transfer of heat exchanger accomodated by surface engineering. One of the surface passive technique applications is groove. Incising groove in pipe as concerned wide consideration as it need no additional power, decrease in weight of system and hence give more benefit in heat transfer. The characteristics of heat transfer in grooved double pipe heat exchanger was investigated experimentally in this article. The aim of this investigation is to reveal the phenomenon of temperature characteristics of cold fluid in the heat transfer process in the grooved double pipe heat exchanger. In this study, water are used as both hot and cold fluid with counter flow pattern, and the water flow rate equal to 15 lpm for both fluid. Grooves were incised on the annulus area in the outer wall of tube side with rectangular shape and circumferential pattern. The characteristics of groove dimension that are height of groove is 0,3 mm; distance between grooves is 8 mm; and the groove space which is as independent variables are 1 mm and 2 mm. The data from 1 mm and 2 mm grooves space were compared with no grooved double pipe heat exchanger data (smooth pipe). The hot fluid temperature is 50 ± 0,50C while the cold fluid temperature is 30 ± 0,50C. The temperature data on the inlet and outlet side of heat exchangers for smooth pipe, 1 mm and 2 mm groove space were compared to find out the characteristics of increasing cold fluid temperature. This study used the temperature rate and temperature acceleration method to compare the variables. The result shows that groove installation increases the amount of heat absorbed by cold fluid. The heat exchanger with 1 mm groove spaces, was able to absorb heat about ± 2.3 % better than heat exchanger with 2 mm groove space and 13,1 % better than heat exchanger with no groove

Utilization of coconut shell activated carbon to generate electrical energy using sodium chloride electrolyte

Fossil fuels that are used to generate electrical energy are running low. Besides that, energy generated from fossil fuels causes global warming and climate change due to gas emissions such as carbon dioxide, leading to a greenhouse effect. In addition, the development of small electronic devices has created power demands, from initially in milli watt (mW), to microwatt (μW) level for wireless sensor networks, which generally use batteries as a power supply. Therefore, environmentally friendly and renewable materials like coconut shells are needed to generate electrical energy. This research aims to generate electrical energy from a model using coconut shell activated carbon with sodium chloride (NaCl) electrolyte. The electrical energy generation model is composed of counter electrode–electrode–counter electrode. The electrode used was coconut shell–activated carbon. Three counter electrodes were used: aluminum, zinc and copper plates. The electrolyte used was sodium chloride (NaCl) solution. The electrolyte was injected between the electrode and the counter electrode, and heat was applied. When the electrolyte was injected into the electrical energy generation model, interaction occurred between the ions from the electrolyte and the functional groups, the pores of the activated carbon, and the counter electrode, and then electrons were released. The research results show that the voltage produced due to an increase in temperature up to ΔT=54 °C, is 0.875 volts for aluminum, 0.767 volts for zinc and 0.091 volts for copper. The average thermal voltage sensitivity (dV/dT) for aluminum is 68.99297 mV/°C, while that for zinc is 61.34319 mV/°C, and copper is 7.02533 mV/°C. The currents produced by aluminum, zinc and copper are 5.9 μA, 3.8 μA and 0.157 μA, respectivel

RANCANG BANGUN PURWARUPA TEKNOLOGI MIKROHIDRO MENGGUNAKAN KONSEP HIDRO FLUTTER

The decline of the world oil reserves is a global crisis for decades to come. The search for renewable energy alternatives is an urgent topic of current research trends. Indonesia has an abundance of energy availability in the form of potential microhydro development. This research is a research of development of new innovative technology in microhydro technology in the form of conversion technique of water flow energy into electric energy using hydro flutter technology. In this research, the development of new tool to convert energy from water flow into electrical energy was developed. A prototype was built that can extract energy from the water stream at times into mechanical energy ready for conversion into electrical energy using the hydro flutter principle of a flexibly mounted free leading edge cantilevered rigid plate. The advantages of the new concept are the simplicity of the design and the ability to clean the system by itself, thereby reducing the maintenance costs.Menurunnya cadangan minyak dunia menjadi krisis global untuk beberapa dasawarsa ke depan. Pencarian alternatif energi terbaharui menjadi topik urgen tren penelitian saat ini. Indonesia memiliki keberlimpahan ketersediaan energi berupa potensi pengembangan mikrohidro. Penelitian ini merupakan penelitian pengembangan teknologi inovatif baru dalam teknologi mikrohidro berupa teknik pengkonversian energi aliran air menjadi energi listrik menggunakan teknologi hidro flutter. Dalam penelitian ini dilakukan pengembangan alat baru pengkonversian energi dari aliran air menjadi energi listrik. Sebuah purwarupa dibangun yang bisa pengekstrak energi dari aliran air di kali menjadi energi mekanik yang siap di konversi menjadi energi listrik menggunakan prinsip hydro flutter dari sebuah flexibly mounted free leading edge cantilevered rigid plate. Keunggulan dari konsep baru yang ditawarkan adalah kesederhanaan dari desain dan kemampuan untuk membersihkan sistem sendiri sehingga mengurangi biaya pemeliharaan

HEAT TRANSFER ENHANCEMENT AND FRICTION IN DOUBLE PIPE HEAT EXCHANGER WITH VARIOUS NUMBER OF LONGITUDINAL GROOVES

It has been found out that heat exchangers with longitudinal grooves produce better heat transfer than those without longitudinal grooves. However, up to now, there have been few investigations and applications of longitudinal grooves in relation to heat transfer associated with friction from the annulus of a heat exchanger. The present investigation examined the effects of longitudinal grooves in a double pipe heat exchanger on the characteristics of heat transfer and friction. Longitudinal rectangular grooves were carved into the outer side of a tube at a specified depth (t) and width (l). The effect of the number of longitudinal grooves, Reynolds number (Re), on the thermal and hydraulic performance was evaluated based on the heat exchanger experimental data. A total of four pipes were used: one pipe with 2 grooves, one pipe with 4 grooves, one pipe with 6 grooves and one pipe with 8 grooves. Water, hot and cold, was used as the working fluid. The test was performed with the cold water as the working fluid, with the Reynolds number from about 33 000 to 46 000 in a counter-flow scheme. The result showed that the number of grooves improved the heat transfer and caused a pressure drop. The increase in heat transfer ranged from 1.05 to 1.15, and the pressure loss of the system reached almost 30% as compared with the smooth annulus, the annulus with no groove. The installation of longitudinal grooves in a heat exchanger system enhanced the process of the heat flow through the boundary but provided a compensation for the pressure loss, which was correlated with the friction and pumping power

PERAN PENGELOMPOKAN MOLEKUL PADA HYDROUS ETANOL TERHADAP KINERJA MESIN

In this study observed the role of molecular clustering on engine performance produced by hydrous ethanol fuel (95.5% v). The test was performed using variation load for four-cylinder motor. Engine performance is measured using Brake Power Engine load cell type indicator TD 800PM. The engine performance produced by anhydrous ethanol was also tested. The resulting engine performance of both fuels is compared. The results showed that the power produced by hydrous ethanol was slightly higher than that of anhydrous ethanol. The charging effisiency generated by hydrous ethanol is upper than that of anhydrous ethanol.Pada penelitian ini diamati peran pengelompokan molekul terhadap kinerja mesin yang dihasilkan bahan bakar hydrous etanol (95,5%v). Pengujian dilakukan menggunakan pembebanan bervariasi pada motor bakar satu silinder empat langkah. Kinerja mesin diukur menggunakan Engine Brake Power indikator load cell tipe TD 800PM. Kinerja mesin yang dihasilkan oleh anhydrous etanol juga diuji. Kinerja mesin yang dihasilkan kedua bahan bakar tersebut dibandingkan. Hasil penelitian menunjukkan Daya mesin yang dihasilkan hydrous etanol sedikit lebih tinggi dari anhydrous etanol. effisiensi pengisian yang dihasilkan oleh hydrous etanol lebih tinggi dari anhydrous etanol

PENINGKATAN PERPINDAHAN PANAS PADA FAN COIL UNIT (FCU) DENGAN NANOPARTI Al2O3

Experimental studies on Fan Coil Unit (FCU) were conducted to investigate heat transfer characteristics due to the addition of Al2O3 nanoparticles. The aims of this study was to reveal the phenomenon of nanofluid particle influences on heat transfer performance indicators. This investigation used tube and fin FCU type with cold fluid is water-Al2O3 nanofluid and hot fluid is ambient air. The cold fluid volume flow rate is 15 lpm and the hot fluid mass flow rate is 0.48 kg/s. The concentration of nanoparticles was 0.1%. The ambient air temperature inlet of FCU is 28 ± 0,50C while the cold fluid temperature entering the FCU is 19 ± 0,50C. In this study the performance parameters on cold fluid with nanoparticles were compared with no nanoparticles. The results showed that the small addition of nanoparticles in cold fluid increased heat transfer in FCU by 9.2%.Eksperimental studi pada Fan Coil Unit (FCU) dilakukan untuk menginvestigasi karakteristik perpindahan panas akibat penambahan nanopartikel Al2O3. Tujuan penelitian ini adalah untuk mengungkap fenomena pengaruh nanofluid partikel pada indikator kinerja perpindahan panas. Pada penelitian ini digunakan FCU jenis tube and fin dengan fluida dingin adalah nanofluid Al2O3 dan fluida panas adalah udara. Laju aliran volume fluida dingin 15 lpm dan laju aliran massa fluida panas sebesar 0,48 kg/s. Konsentrasi nanopartikel yang digunakan pada penelitian ini adalah 0,1%. Temperatur udara lingkungan masuk FCU adalah 28±0,50C sedangkan temperatur fluida dingin yang memasuki FCU adalah 19±0,50C. Pada penelitian ini parameter kinerja pada fluida dingin dengan nanopartikel dibandingkan dengan tanpa nanopartikel. Hasil penelitian menunjukan pemakaian nanopartikel pada fluida dingin mampu meningkatkan perpindahan panas pada FCU sebesar 9,2%

Inovasi Kincir Hidro Energi untuk Peningkatan Pariwisata Air Terjun Blemantung di Desa Pujungan Pupuan Tabanan-Bali

Pandemi yang telah terjadi selama ini menyebabkan penurunan ekonomi para pelaku pariwisata di Bali secara drastis. Para pemilik logistik kepariwisataan seperti bangunan hotel, villa, dan jenis fasilitas lainnya sebagai pendukung kepariwisataan mengalami kesulitan dalam biaya perawatan fasilitas yang dimiliki. Konsumsi energi yang tinggi menjadi komponen biaya yang paling tinggi dan telah menjadi permasalahan di berbagai bidang industri lainnya. Mitra kegiatan ini menargetkan pembuatan akomodasi dan kegiatan wisata (event tourism) berbasis energi dan teknologi ramah lingkungan (green technology) dengan memanfaatkan dan mendukung objek wisata air terjun blemantung. Teknologi kincir hidro energi dibuat sebagai pengembangan pariwisata di Air Terjun Blemantung Desa Pujungan Tabanan-Bali. Energi air di salah satu bagian dari air terjun blemantung akan dimanfaatkan sebagai sumber energi listrik dengan memasang sebuah kincir air sehingga energi air dapat dikonversikan menjadi energi listrik. Peralatan yang dibutuhkan dalam kegiatan ini meliputi; kincir air, generator permanent magnet, dan baterai atau aki. Selain itu, peralatan pendukung untuk instalasi kincir hidro energi ini meliputi: saluran/kanal penampung air terjun, pemipaan ke Nozzle (penstock) dan sistem instalasi kelistrikan untuk baterai dan penggunaan output energi listrik. Instalasi Kincir hidro energi ini digunakan untuk memberikan tambahan energi listrik untuk konsumsi energi bangunan dan logistik pariwisata di air terjun blemantung. Penggunaan battery pack (deep cycle) dapat memberikan kemudahan dan efisiensi dalam manajemen energi untuk tipe sumber energi air kecil. Selain itu, instalasi peralatan di lokasi wisata dapat memberikan pemandangan tambahan untuk dinikmati oleh wisatawan baik domestik maupun mancanegara. Dalam hal ini pertimbangan seni (artistik) dalam instalasi peralatan kincir hidro energi juga menjadi pertimbangan utama pelaksanaan kegiatan ini. Luaran dalam kegiatan ini adalah unit kincir hidro energi yang telah dipasang di wilayah air terjun blemantung dan pemberdayaan masyarakat dalam merawat dan penggunaan energi dalam lingkup kepariwisataan di Desa Pujungan Tabanan Bali. Dalam kegiatan ini telah dapat dihasilkan kincir air yang dapat berputar rata-rata 550 rpm dan mengahasilkan tegangan 17 volts. Pembebanan dengan lampu penerangan telah diketahui dapat diberikan sampai 25 watts