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Pengukuran Koefisien Perpindahan Kalor Evaporasi Refrigeran R-134a di dalam Saluran Halus Horizontal dengan Variasi Kualitas Uap Santosa, Tito Hadji Agung; Nadjib, Muhammad; Thoharudin, Thoharudin; Suyono, Warsito Kabul
ROTASI Vol 20, No 1 (2018): VOLUME 20, NOMOR 1, JANUARI 2018
Publisher : Departemen Teknik Mesin, Fakultas Teknik, Universitas Diponegoro

Nilai koefisien perpindahan kalor evaporasi dari suatu refrigeran sangat penting dalam desain termal evaporator mesin pendingin. Perubahan fasa di dalam evaporator akan terjadi dari fasa cair menjadi fasa uap. Pola aliran yang terbentuk pada proses perubahan fasa tersebut dapat mempengaruhi nilai koefisien evaporasi. Penentuan koefisien evaporasi sulit dilakukan secara teori sehingga mutlak dilakukan secara eksperimental. Penelitian ini bertujuan untuk menentukan koefisien perpindahan kalor evaporasi refrigeran R-134a pada saluran halus horisontal dengan variasi kualitas uap. Alat uji berupa siklus refrigerasi kompresi uap yang dimodifikasi. Perangkat orifice-manometer, pemanas listrik, seksi uji, dan sejumlah termokopel serta indikator tekanan ditambahkan dalam alat uji. Seksi uji berupa pipa ganda aliran berlawanan arah dengan fluida udara sebagai pemanas. Parameter yang diatur adalah laju aliran massa dan kualitas uap dengan beban pendinginan konstan. Laju aliran massa divariasikan dengan menggunakan inverter yang diatur pada frekuensi 14, 16, 18, 20, dan 22 Hz. Inverter dikopel dengan motor listrik sebagai pengerak kompresor. Voltase pemanas listrik divariasikan untuk mengubah kualitas uap refrigeran. Hasil penelitian menunjukkan bahwa dengan memvariasikan kualitas uap, nilai koefisien perpindahan kalor evaporasi naik seiring dengan naiknya kualitas uap pada laju aliran massa yang konstan. Variasi fluks massa tidak secara tegas memberikan hubungan dengan kenaikan nilai koefisien perpindahan kalor evaporasi.

Pengukuran Laju Pelepasan Kalor pada Tangki SWH dengan Pipa Berisi Campuran Paraffin Wax dan Serbuk Tembaga 10% Berat Santosa, Tito Hadji Agung; Yustianto, Sri Hannadhitya Farhan
JMPM (Jurnal Material dan Proses Manufaktur) Vol 4, No 1 (2020): JUNI 2020
Publisher : Universitas Muhammadiyah Yogyakarta

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.18196/jmpm.v4i1.9306

Penggunaan air panas banyak digunakan pada hotel, homestay, dan lain-lain. Pemanas air masih banyak menggunakan bahan bakar gas LPG yang semakin berkurang sehingga diperlukan sumber energi alternatif. Solar Water Heater (SWH) adalah aplikasi pemanas air yang menggunakan energi panas matahari untuk memanaskan air. Pada SWH konvensional, air sebagai media penyimpan panas di tangki. Air memiliki densitas yang besar sehingga konstruksi akan berat dan memerlukan penguatan pada rangka atap untuk pemasangan SWH. Paraffin wax adalah jenis phase change material (PCM) yang memiliki densitas yang rendah sehingga ringan dan memiliki densitas energi yang besar sehingga dapat menampung energi yang besar untuk volume yang kecil. Namun, paraffin wax memiliki konduktivitas termal yang rendah sehingga perlu ditambahkan serbuk Cu untuk meningkatkan konduktivitas termalnya. Pada penelitian ini, digunakan campuran paraffin wax dengan serbuk Cu 10% berat. Tujuan penelitian ini adalah mengetahui laju pelepasan kalor air dan laju pelepasan kalor campuran PCM. Penelitian ini menggunakan empat variasi debit air, yaitu 1; 1,5; 2; dan 2,5 LPM. Penelitian ini dilakukan dengan cara discharging bertahap pada setiap lima menit, air keran dibuka kemudian setelah lima menit ditutup. Pengambilan data dilakukan mulai pada suhu tangki 70 ÌŠC dan berakhir ketika suhu bak air penampung mencapai 35 ÌŠC. Data yang diambil saat proses discharging adalah suhu air pada tangki dan suhu PCM di dalam kapsul di tangki. Laju pelepasan kalor ditentukan dengan perhitungan kalor kumulatif yang dilepaskan oleh air dan campuran PCM serta waktunya. Hasil penelitian menunjukkan bahwa semakin besar debit air, semakin besar pula laju pelepasan kalornya. Laju pelepasan kalor air terbesar sebesar 790 J/s, sedangkan laju pelepasan kalor oleh campuran PCM dan serbuk Cu sebesar 101,44 J/s. Dari hasil ini, masih diperlukan penelitian lanjutan dengan persentase serbuk Cu yang lebih besar sehingga laju pelepasan kalor campuran PCM dapat mendekati laju pelepasan kalor air.Â Hot water is widely used in hotels, homestays, and others. Water heaters still use a lot of LPG gas fuel, decreasing so that alternative energy sources are needed. Solar Water Heater (SWH) is a water heater application that uses solar thermal energy to heat water. In conventional SWH, water is used as a heat storage medium in the tank. Water has a large density, so the construction will be heavy and requires reinforcement on the roof frame for SWH installation. Paraffin wax is a type of phase change material (PCM) with a low density so that it is light and has a large energy density to accommodate large amounts of energy for a small volume. However, paraffin wax has low thermal conductivity, so it is necessary to add Cu powder to increase its thermal conductivity. In this study, a mixture of paraffin wax and 10% Cu powder was used. This study aimed to determine the rate of heat release of water and the rate of heat release of the PCM mixture.This study uses four water discharge variations, namely 1; 1.5; 2; and 2.5 LPM. This research was conducted through gradual discharging where tap water was opened every five minutes and then closed for five minutes. Data collection was carried out starting at a tank temperature of 70 ÌŠC and ending when the reservoir water temperature reached 35 ÌŠC. During the discharging process, the data taken are the water temperature in the tank and the PCM temperature in the capsule in the tank. Rate of heat released is determined by calculating cumulative heat released by the water dan the mixture of PCM and the total time. The results showed that the greater the water discharge, the greater the rate of heat release. The largest water heat release rate was 790 J / s, while the heat release rate by a mixture of PCM and Cu powder was 101.44 J / s. From these results, further research is needed with a larger percentage of Cu powder so that the rate of heat release of the PCM mixture can approach the rate of water heat releaseÂ

Thermal Stratification Characteristics of Storage Tanks on Solar Water Heater Inserted with Latent Heat Material Nadjib, Muhammad; Wahyudi, Wahyudi; Santosa, Tito Hadji Agung; Hidayat, Yaafi
Semesta Teknika Vol 27, No 1 (2024): MEI
Publisher : Universitas Muhammadiyah Yogyakarta

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.18196/st.v27i1.21753

As a latent heat medium, phase change material (PCM) can be applied to heat storage for solar water heaters (SWH). The method used to place PCM is to put it in a capsule. Thermal stratification is critical in generating SWH thermal efficiency. Installation of horizontal capsules in the tank has no known effect on thermal stratification. This paper aims to study the thermal stratification in active-type SWH incorporating PCM. A cylindrical capsule containing the PCM was placed inside the tank. The thermocouple was installed on both the water and PCM sides. The charging process was conducted indoors, and the water flow rate varied from 1, 2, and 3 LPM. Water temperature data for each variation was analyzed to evaluate the thermal stratification. Richardson number analysis proved that thermal stratification was formed in all water flow rates. It was found that a low water flow rate results in high thermal stratification.

Performance of Motorcycle Fueled with Pertalite‒LDPE Pyrolytic Oil Blendings Thoharudin, Thoharudin; Santosa, Tito Hadji Agung; Sukmana, Rifky Adji
JMPM (Jurnal Material dan Proses Manufaktur) Vol 8, No 1 (2024): Juni
Publisher : Universitas Muhammadiyah Yogyakarta

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.18196/jmpm.v8i1.22274

Plastic use has expanded substantially, and its waste is primarily disposed of in landfills, which further harm ecosystems owing to inadequate waste management. Pyrolysis, which converts plastic waste into liquid fuel, is one of the potential chemical recycling alternatives for plastic. The purpose of this study is to determine the viability of using pyrolytic oil from an LDPE grocery bag as an alternative fuel for a four-stroke spark ignition motorcycle engine. The LDPE grocery bag was pyrolyzed at 500 oC at a heating rate of 3 oC/min, and the condensed pyrolytic vapor's characteristics were determined. Torque, power, and fuel consumption were investigated using a four-stroke spark ignition motorbike powered by pertalite‒LDPE pyrolytic oil blends. The results reveal that the properties of LDPE pyrolytic oil and pertalite were considerably different; hence, when the blending fuel was applied to the motorcycle, the engine torque and power decreased at low engine speed (2000‒3500 rpm), about equal at medium speed (3500‒5500 rpm), and increased at high engine speed (5500‒8500 rpm). Furthermore, the greater blending fuel greatly reduced fuel usage due to the high viscosity of the LDPE pyrolytic oil.

Impact of Mass Flow Rate on Thermal Behavior of PCM-Based SWH during Charging Operations Nadjib, Muhammad -; Wahyudi, Wahyudi; Santosa, Tito Hadji Agung; Febriansyah, Tegar Bagaskara
JMPM (Jurnal Material dan Proses Manufaktur) Vol 8, No 1 (2024): Juni
Publisher : Universitas Muhammadiyah Yogyakarta

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.18196/jmpm.v8i1.21848

Using phase change materials in solar water heaters presents an intriguing prospect due to their notable energy density and potential for substantial thermal energy storage capacity. In the context of active-type solar water heaters, careful consideration must be given to the water flow rate as a crucial parameter. This paper investigates the thermal dynamics of active-type solar water heaters equipped with phase change materials, examining variations in mass flow rate during the charging process. Indoor experiments utilized horizontal tanks, flat plate collectors, pumps, and solar simulators. Cylindrical capsules filled with paraffin wax were employed and arranged horizontally within the tank, while K-type thermocouples were utilized to monitor water and paraffin wax temperatures. Charging procedures were executed over 160 minutes with mass flow rate adjustments. Data analysis was performed to evaluate the system's thermal performance during charging. Results indicate higher mass flow rates correspond to increased instantaneous, cumulative heat storage, and charging efficiency. The mass flow rate notably affects the thermal efficiency of solar water heater systems incorporating phase change materials.

Impact of Mass Flow Rate on Thermal Behavior of PCM-Based SWH during Charging Operations Nadjib, Muhammad -; Wahyudi, Wahyudi; Santosa, Tito Hadji Agung; Febriansyah, Tegar Bagaskara
JMPM (Jurnal Material dan Proses Manufaktur) Vol. 8 No. 1 (2024): Juni
Publisher : Universitas Muhammadiyah Yogyakarta

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.18196/jmpm.v8i1.21848

Using phase change materials in solar water heaters presents an intriguing prospect due to their notable energy density and potential for substantial thermal energy storage capacity. In the context of active-type solar water heaters, careful consideration must be given to the water flow rate as a crucial parameter. This paper investigates the thermal dynamics of active-type solar water heaters equipped with phase change materials, examining variations in mass flow rate during the charging process. Indoor experiments utilized horizontal tanks, flat plate collectors, pumps, and solar simulators. Cylindrical capsules filled with paraffin wax were employed and arranged horizontally within the tank, while K-type thermocouples were utilized to monitor water and paraffin wax temperatures. Charging procedures were executed over 160 minutes with mass flow rate adjustments. Data analysis was performed to evaluate the system's thermal performance during charging. Results indicate higher mass flow rates correspond to increased instantaneous, cumulative heat storage, and charging efficiency. The mass flow rate notably affects the thermal efficiency of solar water heater systems incorporating phase change materials.

Performance of Motorcycle Fueled with Pertalite‒LDPE Pyrolytic Oil Blendings Thoharudin, Thoharudin; Santosa, Tito Hadji Agung; Sukmana, Rifky Adji
JMPM (Jurnal Material dan Proses Manufaktur) Vol. 8 No. 1 (2024): Juni
Publisher : Universitas Muhammadiyah Yogyakarta

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.18196/jmpm.v8i1.22274

Plastic use has expanded substantially, and its waste is primarily disposed of in landfills, which further harm ecosystems owing to inadequate waste management. Pyrolysis, which converts plastic waste into liquid fuel, is one of the potential chemical recycling alternatives for plastic. The purpose of this study is to determine the viability of using pyrolytic oil from an LDPE grocery bag as an alternative fuel for a four-stroke spark ignition motorcycle engine. The LDPE grocery bag was pyrolyzed at 500 oC at a heating rate of 3 oC/min, and the condensed pyrolytic vapor's characteristics were determined. Torque, power, and fuel consumption were investigated using a four-stroke spark ignition motorbike powered by pertalite‒LDPE pyrolytic oil blends. The results reveal that the properties of LDPE pyrolytic oil and pertalite were considerably different; hence, when the blending fuel was applied to the motorcycle, the engine torque and power decreased at low engine speed (2000‒3500 rpm), about equal at medium speed (3500‒5500 rpm), and increased at high engine speed (5500‒8500 rpm). Furthermore, the greater blending fuel greatly reduced fuel usage due to the high viscosity of the LDPE pyrolytic oil.

Evaluation of Motorcycle Fueled with Blends of Gasoline and Pyrolytic Oil from Plastic‒Palm Kernel Shell Co-Pyrolysis Thoharudin, Thoharudin; Santosa, Tito Hadji Agung; Iswandi, Iswandi
ROTASI Vol 27, No 1 (2025): VOLUME 27, NOMOR 1, JANUARI 2025
Publisher : Departemen Teknik Mesin, Fakultas Teknik, Universitas Diponegoro

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.14710/rotasi.27.1.15-22

This study explores the co-pyrolysis of plastic grocery bags and palm kernel shells (PKS) as a sustainable solution for addressing plastic waste and producing renewable energy. A stainless-steel batch reactor operating at 500oC produced pyrolytic oil, char, and non-condensable gases, with a product yield of 48.3%, 26.7%, and 25.0%, respectively. Pyrolytic oil was characterized by higher viscosity, density, and oxygen content but a lower heating value compared to gasoline (pertalite). Various blends of pyrolytic oil (0–30%) with pertalite were tested in a 108 cc motorcycle engine. While pure pertalite offered better torque and power at low speeds, pertalite with 10% and 20% pyrolytic oil showed comparable engine performance at low to medium rotational speeds and better performance at high rotational speeds. In addition, blends with higher pyrolytic oil concentrations improved fuel efficiency, with the 30% blend achieving the best fuel economy at 33.3 km/L. The study concludes that pyrolytic oil can be a viable alternative fuel for motorcycles, particularly in carburetor systems, but requires further refinement to address particulate content and enhance compatibility with fuel injection systems.

Perancangan Teknologi Panel Surya Sebagai Suplai Penerangan di Area Wisata Edukasi Bendungan Sungai Pabelan Rahman, Muhammad Budi Nur; Riyanta, Bambang; Sosiati, Harini; Santosa, Tito Hadji Agung; Suwanda, Totok; Suminto, Joko; Mujiyana, Mujiyana; Kurniawan, Aditya; Muhajir, Muhajir
Prosiding Seminar Nasional Program Pengabdian Masyarakat Vol. 5: 2: December 2022
Publisher : Universitas Muhammadiyah Yogyakarta

Show Abstract | Download Original | Original Source | Check in Google Scholar

Energi terbarukan merupakan isu trend saat ini. Pemerintah, lembaga independen, akademisi, dan masyarakat telah meluncurkan banyak program terkait penggunaan energi terbarukan, yang pada akhirnya mengubah energi tersebut menjadi listrik. Energi listrik ini digunakan untuk berbagai kebutuhan, terutama sebagai sumber tenaga dalam kehidupan sehari-hari. Apabila listrik dari sumber terbarukan diperoleh dari pedesaan maka listrik yang tersedia akan sangat bermanfaat bagi masyarakat sehingga desa tidak harus bergantung sepenuhnya pada pembangkit listrik utama Indonesia. Bendungan Sungai Pabelan sebagai infrastruktur sistem perairan untuk lahan pertanian sangat potensial dimanfaatkan oleh masyarakat sebagai tujuan wisata. Pemanfaatan area bendungan sebagai objek wisata edukasi dirasa sangat tepat mengingat wilayah Desa Pabelan merupakan kawasan pintu masuk area wisata internasional Borobudur. Area tersebut sebenarnya memiliki potensi yang sangat besar jika dijadikan sebagai salah satu tujuan wisata. Hal tersebut menjadi keunggulan dan potensi yang sangat besar khususnya dalam mengenalkan destinasi wisata baru kepada masyarakat. secara umum, objek wisata bendungan Sungai Pabelan dapat dikembangkan menjadi beberapa jenis wisata, seperti wisata jeep adventure, camping ground, wisata edukasi, dan outbond. Program pengabdian ini, jenis objek wisata yang akan dikembangkan di area bendungan adalah objek wisata edukasi. Bentuk pengembangan yang akan dilakukan yaitu dengan mengintegrasikan sentra produksi kerajinan bambu dan alat rumah tangga dan pertanian yang ada di wilayah Desa Pabelan. Di sekitar area bendungan Sungai Pabelan tersebut juga akan dibuatkan beberapa bangunan atau gazebo sederhana sehingga dapat dijadikan sebagai pusat wahana edukasi yang disediakan perlengkapan dan peralatan untuk mendukung pengembangan media wisata edukasi. Salah satu kebutuhan sehari-hari yang dibutuhkan adalah energi listrik untuk penerangan lingkungan. Oleh karena itu diharapkan melalui pengabdian masyarakat ini dapat memberikan teknologi tepat guna dan menambah pengetahuan bagi warga tentang pembangkit listrik tenaga surya dan cara pemasangannya. Output tujuan dari program pengabdian ini adalah untuk membuat dan mengaplikasikan teknologi tepat guna berbentuk instalasi pembangkit listrik tenaga surya sederhana untuk lampu penerangan jalan di lingkunagan bendungan sungai Pabelan. Dengan adanya pengembangan wisata edukasi di area bendungan Sungai Pabelan, masyarakat akan dapat merasakan manfaat secara langsung melalui kegiatan ekonomi yang terjadi di sekitar area bendungan. Dengan demikian, pengembangan objek wisata edukasi di area bendungan Sungai Pabelan diharapkan dapat meningkatkan kesejahteraan masyarakat di sekitar area bendungan. Hasil pengabdian akan dipublikasikan dalam bentuk video profil wahana wisata edukasi dan jurnal ilmiah yang diterbitkan secara online sehingga dapat dijadikan referensi wisata edukatif yang ramah untuk anak-anak.

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