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All Journal Semesta Teknika JMPM (Jurnal Material dan Proses Manufaktur)
Tito Hadji Agung Santosa
Universitas Muhammadiyah Yogyakarta
Engineering Mechanical Engineering

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Efek Variasi Beban Pendinginan Terhadap Coefficient Of Performance (Cop) Alat Uji Pengukuran Koefisien Evaporasi Menggunakan Refrigeran R-134A Tito Hadji Agung Santosa; Muhammad Nadjib; Thoharuddin Thoharuddin; Muhammad Akhid Riza
Semesta Teknika Vol 20, No 2 (2017): NOVEMBER 2017
Publisher : Universitas Muhammadiyah Yogyakarta

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.18196/st.v20i2.3412

Abstract

Investigation of the cooling load effect toward Coefficient of Performance (COP) is important to conduct. The Coefficient of Performance (COP) is related with compressor work and refrigeration capacity in order to produce a refrigeration system which have a high COP. The high COP value can be reached with minimum compressor work, however it has a maximum refrigeration capacity. This research is to know the effect of cooling load variation toward the performance of experimental device of evaporation heat transfer measurement. By knowing the changing of performance toward cooling load variation, it can be useful in design of an effective and efficient air conditioning system.The method of coolecting data is by experimental method that is by varying water mass flowrate (cooling load) which is flowed to evaporator. An evaporator is soak in a 30 xm x 15 cm x 20 cm water box. Water flowrate can be varied and be masured by a water rotameter. Refrigerant is using Freon R-134a. Experiment is conducted with an evaporation heat transfer coefficient device. The device is a model of modified refrigeration system by adding instruments : an orifice, a test section, and an electric heater. Thermocouple and some pressure gauges is installed at some points which has been determined. Thermocouple and pressure gauges is used to collect temperature and pressure data. After conducting an experiment by evaporator cooling load variation, temperature and pressure data is got. Furthermore based on the temperature and pressure data, the enthalpy is got and can be used to counting the compressor power. Refrigeration capacity can be counted from total heat absorbed by evaporator from water and is divided refrigerant mass flowrate. In this research is got results that cooling load given in evaporator enfluences the COP of the experiment device. By increasing in cooling load at the determined variation, the Coefficient of Performance (COP) of the device is increase. In this research it get results increasing of COP at some refrigerant mass flowrate. The maximum result is get at minimum range inverter variation, that is 16 Hz (ṁr = 9,4 g/s - 10,26 g/s) and the maximum cooling load variation is 2 LPM with COP of 4,96. Whereas the minimum results is get at the maximum inverter range variation, that is 24 Hz (ṁr = 11,83 g/s - 12,25 g/s) and the minimum cooling load variation is 1 LPM with COP of 1,98. This research give some information, if a cooling load of an air conditioning room is chanhing, then it will change the parameter (temperature and pressure) and COP of the air conditioning system in a room.
Pengaruh Variasi Debit Air Terhadap Unjuk Kerja Termal Tangki Pemanas Air Tenaga Surya yang Berisi Phase-Change Material Tito Hadji Agung Santosa; Angga Dwi Sentosa; Darmawan Mukhlisin
JMPM (Jurnal Material dan Proses Manufaktur) Vol 6, No 1 (2022): Juni
Publisher : Universitas Muhammadiyah Yogyakarta

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.18196/jmpm.v6i1.14795

Abstract

Integrasi air dan phase-change material (PCM) menarik diterapkan pada pemanas air tenaga surya (PATS). Teknik enkapsulasi PCM menggunakan kapsul dapat dilakukan di dalam tangki PATS. Sejauh ini, karakteristik termal di dalam tangki PATS posisi horizontal berisi PCM yang berkaitan dengan variasi debit air belum pernah diungkap. Penelitian ini bertujuan untuk menyelidiki karakteristik termal tangki PATS yang melibatkan PCM dengan variasi debit air.  Eksperimen menggunakan PATS sistem aktif dengan volume tangki 60 liter. Kapsul silinder berjumlah 24 buah diisi paraffin wax dan dimasukkan ke dalam tangki PATS. Termokopel sebanyak 20 buah dipasang di sisi air dan paraffin wax. Proses charging dilakukan selama 160 menit. Variasi debit air yang digunakan adalah 1 lpm, 2 lpm dan 3 lpm. Data temperatur air dan paraffin wax digunakan untuk menganalisis kinerja termal PATS. Hasil karakteristik termal dari tiga eksperimen kemudian dibandingkan. Energi termal akumulatif yang diperoleh untuk debit aliran 1 lpm, 2 lpm dan 3 lpm masing-masing adalah 12,09 MJ, 14,08 MJ dan 16,59 MJ. Penambahan debit aliran air mampu meningkatkan unjuk kerja termal sistem PATS yang melibatkan PCM.The integration of water and phase-change materials (PCM) is interestingly applied to solar water heaters (SWH). PCM encapsulation technique using capsules can be carried out in an SWH tank. So far, the thermal characteristics in the horizontal position of the SWH tank containing PCM related to variations in water flow have not been revealed. This study investigates the thermal characteristics of SWH tanks involving PCM with variations in water discharge. This experiment uses an active SWH system with a tank volume of 60 liters. The 24 cylindrical capsules were filled with paraffin wax and put into the SWH tank. There were twenty thermocouples installed on the waterside and paraffin wax. The charging process is carried out for 160 minutes. Variations of water discharge used are 1 lpm, 2 lpm, and 3 lpm. Water temperature data and paraffin wax were used to analyze the thermal performance of SWH. The results of the thermal characteristics of the three experiments were then compared. The accumulative thermal energy obtained for flow rates of 1 lpm, 2 lpm, and 3 lpm was 12.09 MJ, 14.08 MJ, and 16.59 MJ, respectively. The addition of the water flow rate can increase the thermal performance of the SWH system involving PCM.
Pengukuran Laju Pelepasan Kalor pada Tangki SWH dengan Pipa Berisi Campuran Paraffin Wax dan Serbuk Tembaga 10% Berat Tito Hadji Agung Santosa; Sri Hannadhitya Farhan Yustianto
JMPM (Jurnal Material dan Proses Manufaktur) Vol 4, No 1 (2020): Juni
Publisher : Universitas Muhammadiyah Yogyakarta

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

Abstract

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 ̊C dan berakhir ketika suhu bak air penampung mencapai 35 ̊C. 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. 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 ̊C and ending when the reservoir water temperature reached 35 ̊C. 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 release 
Penentuan Nilai Kalor Eksperimental LPG dengan Variasi Udara Berlebih dan Variasi Debit LPG 0,4; 0,5; dan 0,6 LPM Tito Hadji Agung Santosa; Muhammad Nadjib; Hardhany Faiz Ikhsan; Tayuh Kinayung Waskitho; Fiqri Elpa Ramadhany
JMPM (Jurnal Material dan Proses Manufaktur) Vol 6, No 1 (2022): Juni
Publisher : Universitas Muhammadiyah Yogyakarta

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.18196/jmpm.v6i1.15728

Abstract

Setiap bahan bakar memiliki nilai kalor (NK) yaitu energi yang dikandung dalam setiap massa dari bahan bakar. Penentuan nilai kalor bahan bakar gas dapat dilakukan dengan kalorimeter aliran. Penelitian ini menggunakan LPG sebagai bahan penelitian. Untuk menjamin semua bahan bakar terbakar, digunakan udara berlebih (excess air). Tujuan dari penelitian ini yaitu untuk mendapatkan NK eksperimental LPG dan efisiensi kalorimeter aliran dengan variasi udara berlebih (excess air). Penelitian ini menggunakan metode pembakaran aktual dengan debit LPG 0,4; 0,5; dan 0,6 LPM dan tujuh variasi excess air (EA) 0% hingga 60% dengan interval variasi 10%. Dari hasil perhitungan didapatkan NK eksperimental dan efisiensi kalorimeter aliran yang mendekati NK LPG teoritik yaitu pada EA 50% sebesar 41.042,16 kJ/kg dan 85%. Namun pada variasi EA 60%, NK eksperimental dan efisiensi mengalami penurunan nilai yaitu 38.142,44 kJ/kg dan 78,66%. Dapat disimpulkan bahwa NK eksperimental LPG naik seiring dengan naiknya udara berlebih hingga 50% dan selanjutnya turun pada udara berlebih 60% karena penambahan udara berlebih selanjutnya akan bersifat sebagai pendinginan. Each fuel has a heating value (HV) which is the energy contained in each mass of the fuel. Determination of the heating value of gas fuel can be done with a flow calorimeter. This research uses LPG as research material. To ensure that all fuel is burned, excess air is used. The purpose of this study was to obtain experimental LPG heating value and flow calorimeter efficiency with excess air variations. This study uses the actual combustion method with an LPG discharge of 0.4; 0.5; and 0.6 LPM and seven variations of excess air (EA) from 0% to 60% with a variation interval of 10%. From the calculation results obtained experimental HV and flow calorimeter efficiency close to theoretical LPG HV, namely at 50% EA of 41,042.16 kJ/kg and 85%. However, at 60% EA variation, experimental HV and efficiency decreased in value, namely 38,142.44 kJ/kg and 78.66%, respectively. It can be concluded that the experimental HV of LPG increases with the increase in excess air by up to 50% and then decreases at 60% excess air because the addition of excess air will act as cooling.
Co-Authors Angga Dwi Sentosa Darmawan Mukhlisin Fiqri Elpa Ramadhany Hardhany Faiz Ikhsan Muhammad Akhid Riza Muhammad Nadjib Muhammad Nadjib Sri Hannadhitya Farhan Yustianto Tayuh Kinayung Waskitho Thoharuddin Thoharuddin