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Pemodelan Temperatur Keluaran Sistem Downhole Heat Exchanger dengan Metoda Elemen Hingga Alamta Singarimbun; Gilang Satria Prayoga
Jurnal Matematika & Sains Vol 17, No 2 (2012)
Publisher : Institut Teknologi Bandung

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Downhole Heat Exchanger (DHE) merupakan salah satu teknologi untuk memanfaatkan energi panas bumi. Secara umum DHE terdiri dari pipa berbentuk U yang ditanam secara vertikal di dalam tanah. Ke dalam pipa DHE dialirkan air dan jika temperatur di bawah tanah cukup tinggi, maka air tersebut akan terpanaskan. Air yang telah terpanaskan bertemperatur tinggi dapat dimanfaatkan misalnya untuk kebutuhan rumah tangga. Dalam penelitian ini, kami mengembangkan sebuah model dalam bentuk simulasi numerik untuk memperkirakan temperatur sebagai keluaran DHE berdasarkan parameter fisik optimal yang mempengaruhi sistem. Sebagai hasilnya, diperoleh kaitan antara debit air yang dimasukkan dengan temperatur keluaran untuk temperatur masukan tertentu. Juga diperoleh hasil berupa kaitan antara temperatur masukan dengan temperatur keluaran untuk debit air tertentu. Parameter ini diharapkan dapat dimanfaatkan sebagai kontrol untuk parameter keluaran yang diinginkan. Kata kunci : DHE, Pipa berbentuk U, Simulasi numerik, Output termal, Debit air, Temperatur keluaran, Temperatur masukan. Â A Model for Temperature Estimation as Output of Downhole Heat Exchanger by Using Finite Element Method Abstract Downhole Heat Exchanger (DHE) is one of the technologies for harnessing geothermal energy. DHE generally consists of a U-shaped pipe planted in the ground vertically. Water is flowed into the DHE pipe and if the temperature below ground is high enough, then the water will be heated. Water that has been heated by high temperature can be used for example for household needs. In this research, we develop a model in the form of numerical simulations to estimate temperature as output of DHE based on the optimal physical parameters that affect the system. As a result, the relationship between water debit discharge and output is obtained as function of temperature. The relationship between temperature insert with the water discharge temperature are obtained also for a specific output. The parameter input can be used as a control for the desired output parameter. Keywords: DHE, U-shaped, Numerical simulation, Thermal output, Water discharge, Temperature output, Input temperature.

Modeling of Reservoir Structure by Using Magnetotelluric Method in the Area of Mt. Argopuro, East Java, Indonesia Singarimbun, Alamta; Gaffar, Eddy Zulkarnaini; Tofani, Panji
Journal of Engineering and Technological Sciences Vol 49, No 6 (2017)
Publisher : ITB Journal Publisher, LPPM ITB

The purpose of this study was to review a regional geothermal system by applying the magnetotelluric method, which is one of the geophysical methods that can be used to map subsurface resistivity structures. This method uses electromagnetic waves of natural resources, namely the interaction of the sun (solar wind) and lightning activity on earth. This study used an inverse modeling method, i.e. the non-linear conjugate gradient method, to estimate the resistivity value as a function of depth at points of sounding, while 2-dimensional modeling was used to describe the distribution of the resistivity values laterally or vertically on a trajectory of measurements. Data were collected from the area of Mt. Argopuro, East Java, where the magnetotelluric method has not been applied before. A geothermal system was found under Mt. Argopuro consisting of altered rock, reservoirs and hot rock with sources of heat associated with high resistivity values (1024 ohm.m). The area has potential for geothermal energy exploration in the future.

Penentuan Strukur Bawah Permukaan Area Panas Bumi Patuha dengan Menggunakan Metoda Magnetik Singarimbun, Alamta; Bujung, Cyrke Adfie Netty; Fatihin, Riva Choerul
Jurnal Matematika dan Sains Vol 18 No 2 (2013)
Publisher : Institut Teknologi Bandung

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Daerah panasbumi Patuha terletak di Jawa Barat sekitar 50 km ke arah Barat daya dari Bandung dengan koordinat 7o9'35,08'' Lintang Selatan dan 92o23'52,24'' Bujur Timur. Dari pengukuran dengan metoda magnetik menunjukkan adanya anomali magnetik pada tiga daerah. Secara geologi, daerah penelitian terdiri dari lapisan sedimen berupa tufa dan terfa lapili, piroklatik andesit, breksi andesite dan basaltic andesit dengan variasi nilai suseptibilitas, k, dari -0,03 hingga 0,25 (dalam unit cgs). Aktivitas vulkanik masih dapat dilihat dari manifestasi fumarol dan sumber air panas. Anomali magnetik di sekitar manifestasi disebabkan oleh lapisan batuan permiabel. Lapisan ini diperkirakan sebagai reservoir yang diprediksi sebagai andesit yang lebih muda dan menjadi sumber energi panasbumi. Kata kunci: metoda magnetik, panas bumi, suseptibilitas, anomali magnetik Abstract Patuha geothermal area is located in West Java about 50 km to the southwest of Bandung with coordinates 7o9'35,08''south latitude and 92o23'52,24'' east longitude. From measurements with magnetic methods indicate the presence of magnetic anomalies in the three regions. Geologically, the area consists of sedimentary layers of lapili tuffs and terfa, pyroclatic andesite, breccia andesite and basaltic andesite with a variation of the susceptibility, k, from -0.03 up to 0.25 (in cgs units). Volcanic activity can be seen from the manifestation of fumaroles and hot springs. Magnetic anomaly at approximately the manifestations are caused by layers of permeable rock. This layer is estimated as the reservoir as the younger andesites and a source of geothermal energy. Keywords : magnetic method, geothermal, susceptibility, magnetic anomaly.

ANALISIS DATA MULTISPEKTRAL UNTUK IDENTIFIKASI POTENSI PANAS BUMI Cyrke A.N. Bujung -; Alamta Singarimbun -; Dicky Muslim -; Febri Hirnawan -; Adjat Sudradjat -
Bionatura Vol 13, No 1 (2011): Bionatura Maret 2011
Publisher : Direktorat Sumber Daya Akademik dan Perpustakaan

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Indikator keterdapatan cebakan panas bumi di bawah permukaan tanah, dapattercermin di permukaan dengan adanya manifestasi permukaan seperti kawahfumarol, mata air panas dan sebagainya. Hal ini memungkinkan untukmengidentifikasi daerah potensi panas bumi berdasarkan ekspresipermukaannya dengan menggunakan citra satelit penginderaan jauh. Penelitianini menggunakan metode penginderaan jauh multispektral Landsat TM(Thematic mapper) untuk analisis spektral reflektansi dan temperatur darimanifestasi permukaan daerah panas bumi. Hasil analisis menunjukkan bahwaanomali spektral reflektansi dari manifestasi permukaan terjadi pada salurandengan panjang gelombang di bawah 0,7 ìm. Sedangkan temperaturmanifestasi permukaan terdeteksi berkisar antara 304,880K sampai dengan308,340K.Kata kunci: multispektral, reflektansi, temperatur, panas bumi

Modeling of Reservoir Structure by Using Magnetotelluric Method in the Area of Mt. Argopuro, East Java, Indonesia Alamta Singarimbun; Eddy Zulkarnaini Gaffar; Panji Tofani
Journal of Engineering and Technological Sciences Vol. 49 No. 6 (2017)
Publisher : Institute for Research and Community Services, Institut Teknologi Bandung

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.5614/j.eng.technol.sci.2017.49.6.9

The purpose of this study was to review a regional geothermal system by applying the magnetotelluric method, which is one of the geophysical methods that can be used to map subsurface resistivity structures. This method uses electromagnetic waves of natural resources, namely the interaction of the sun (solar wind) and lightning activity on earth. This study used an inverse modeling method, i.e. the non-linear conjugate gradient method, to estimate the resistivity value as a function of depth at points of sounding, while 2-dimensional modeling was used to describe the distribution of the resistivity values laterally or vertically on a trajectory of measurements. Data were collected from the area of Mt. Argopuro, East Java, where the magnetotelluric method has not been applied before. A geothermal system was found under Mt. Argopuro consisting of altered rock, reservoirs and hot rock with sources of heat associated with high resistivity values (1024 ohm.m). The area has potential for geothermal energy exploration in the future.

Curie Point Depth Analysis of Lesugolo Area, East Nusa Tenggara, Indonesia Based on Ground Magnetic Data Alamta Singarimbun; Umar Said; Dini Andriani; R. B. Astro; Bakrun Bakrun; I G. P. F. Soerya Djaja; Eleonora Agustine; Pepen Supendi; Wahyu Srigutomo
Journal of Engineering and Technological Sciences Vol. 54 No. 1 (2022)
Publisher : Institute for Research and Community Services, Institut Teknologi Bandung

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.5614/j.eng.technol.sci.2022.54.1.11

The Curie point depth, or magnetic basal depth, of the Lesugolo geothermal area in Ende, Flores Island, East Nusa Tenggara, Indonesia was estimated by performing spectral analysis on spatial magnetic data and transforming it into the frequency domain, resulting in a link between the 2D spectrum of magnetic anomalies and the depths of the top and centroid of the magnetic sources. Shallow Curie point depths of 16 to 18 km were found in the north-northeast to southeast areas of Lesugolo, while deeper depths of 24 to 26 km were found in the southwest. The tectonic setting beneath the central part of Flores Island governs the distribution of the Curie point depths in the area. Shallow Curie point depth zones are associated with high thermal gradients (30 to 34 °C/km) and heat flow (80 to 100 mW/m2). Deep depths, on the other hand, correspond to zones of low thermal gradient (21 to 26 °C/km) and low heat flow (65 to 80 mW/m2). Both the derived thermal gradient and the heat flow maps contribute to a better understanding of the Lesugolo geothermal system’s configuration. This study suggests that the Lesugolo geothermal area’s prospect zone is located in the center of the investigated area, where the Lesugolo normal fault forms its southeastern boundary.

PEMETAAN DAERAH RAWAN LONGSOR DI SEKITAR DAERAH PROSPEK PANAS BUMI PROVINSI JAWA BARAT Linda Handayani; Alamta Singarimbun
JOURNAL ONLINE OF PHYSICS Vol. 2 No. 1 (2016): JOP (Journal Online of Physics) Vol 2 No 1
Publisher : Prodi Fisika FST UNJA

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.22437/jop.v2i1.3448

Eksplorasi potensi panas bumi diklaim sebagai tambang ramah lingkungan, maksudnya tidak terlalu banyak merusak dan tidak terlalu membahayakan lingkungan. Sejatinya benar, namun daerah panas bumi selalu berafiliasi dengan topografi yang sangat kasar, lerengnya terjal, dan jarang dijumpai tanah datar yang luas. Hal ini menyebabkan daerah di sekitar panas bumi rawan terhadap tanah longsor. Jenis batuan yang mudah lepas-lepas, membuat tingkat kerawanan terhadap kemungkinan tanah longsor semakin meningkat. Mengingat daerah panas bumi adalah daerah yang rawan terhadap bencana tanah longsor, maka perlu dilakukan pemetaan daerah rawan longsor untuk meminimalkan korban dan kerugian akibat bencana tersebut. Berdasarkan analisis menggunakan metode probabilistik frekuensi rasio, di sekitar daerah WKP panas bumi, 28,71% adalah daerah yang sangat rawan terhadap bencana longsor, 56,23% masuk dalam kategori rawan longsor, dan hanya 15,06% saja daerah yang aman terhadap bencana longsor tersebut. Kata kunci: Pemetaan, Longsor, Panas Bumi

ANALISIS POTENSI LIKUIFAKSI DI DAERAH SERANGAN BALI SELATAN MENGGUNAKAN METODE PROBABILISTIK DAN METODE GROUND PENETRATING RADAR (GPR) Maya Efiarni Eka Putri; Rahmat Nawi Siregar; Alamta Singarimbun
Jurnal Riset Fisika Indonesia Vol 1 No 2 (2021): Juni 2021
Publisher : Jurusan Fisika, Universitas Bangka Belitung

Likuifaksi dapat mengakibatkan kerusakan tanah secara fisik dan menimbulkan potensi korban jiwa lebih besar. Pulau Bali Selatan merupakan salah satu daerah destinasi wisata dan memiliki potensi likuifaksi cukup tinggi dikarenakan kondisi tanah dan tingginya potensi gempabumi. Pada penelitian analisis potensi likuifaksi di daerah Serangan, Bali Selatan dilakukan dengan menggunakan metode probabilistik dan metode ground penetrating radar (GPR). Penelitian ini bertujuan untuk mendapatkan informasi lapisan dangkal bawah permukaan, penurunan tanah akibat gempabumi secara teoritis, dan probabilitas kejadian likuifaksi di daerah Serangan, Bali Selatan dengan mempertimbangkan beberapa parameter yaitu gempabumi Bali (2020) dan gempabumi Lombok (2018). Data GPR diolah menggunakan software ReflexW 7.0 dan data probabilistik diolah menggunakan software Microsoft Excel 2010. Hasil penelitian probabilistik dan GPR menunjukkan keberadaan muka air tanah pada kedalaman ± 2 m serta probabilitaskejadian likuifaksi sebesar 92.22% dengan percepatan tanah sebesar 0,5749 gal di kedalaman 3,5 m yang berjarak 10 km dari episenter akibat gempabumi dengan magnitudo 7,7. Kata kunci: Muka Air Tanah; Penurunan Tanah; Probabilitas; Software ReflexW 7.0.

Aplikasi Persamaan Peng–Robinson Dalam Memperkirakan Korelasi Konstanta Kesetimbangan Sistem Gas Kondensat Alamta Singarimbun; Amiruddin Takda; Tutuka Ariadji
Indonesian Journal of Physics Vol 13 No 1 (2002): Vol. 13 No.1, Januari 2002
Publisher : Institut Teknologi Bandung

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The pressure of gas condensate reservoir will decrease at the production process. The reduction of pressure under dew point causes gases to condensate into two phase systems i.e. vapor-liquid and its composition. The prediction of phase equilibrium constant of vapor liquid and its compositions is obtained by applying Peng-Robinson equation. Especially for component of hepthane plus (C7+), a new correlation is proposed to determine equilibrium constant gas-liquid and its composition. The data used in this study was field data from several gas wells in Sumatera and Java. The results are an equilibrium constant and a composition as a function of pressure, temperature, specific gravity and molecule weight. The use of a new correlation to other components of gas condensate system (C1–C6 and CO2–N2), gives a good agreement with the standard data in a PVT chart.

A Preliminary Result of Seismoelectric Responses Study on Shallow Fluid-Saturated Layer: Numerical Modeling Using Transfer Function Approach Alamta Singarimbun; Harry Mahardika; Wahyu Srigutomo; Umar Fauzi
Indonesian Journal of Physics Vol 19 No 3 (2008): Vol. 19 No. 3, July 2008
Publisher : Institut Teknologi Bandung

Seismoelectric phenomena occurs when a seismic wave propagating in a fluid-saturated medium and crossing an interface of different fluid-saturated mediums that induces electrical field or cause radiation of an electromagnetic wave where only the electric part is being measured. In this paper, we present our research progress on seismoelectric imaging of shallow fluid-saturated layers. The progress mainly discusses on our finite-difference algorithm which provides an alternative method to simulate seismic wave propagation in fluid saturated porous media generating electric fields through an electrokinetic mechanism called seismoelectric coupling. The target of this numerical simulation is to see whether the seismoelectric responses of coseismic field and interface boundary effect can be image on the seismoelectrogram. The simulation begins with the calculation of seismic displacement by using the classical homogeneous formulation. Next, we calculate the seismoelectric responses using the seismoelectric transfer function. The algorithm is then used to simulate seismoelectric responses created from various conditions of finite-infinite and finite-infinite sand-clay model, surface to downhole and crosshole configurations.

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