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All Journal International Journal of Renewable Energy Development Jurnal Keteknikan Pertanian Jurnal Pengelolaan Sumberdaya Alam dan Lingkungan (Journal of Natural Resources and Environmental Management) agriTECH Agrokreatif Jurnal Ilmiah Pengabdian kepada Masyarakat Warta IHP (Warta Industri Hasil Pertanian) Jurnal Teknik Pertanian Lampung (Journal of Agricultural Engineering) Jurnal Teknik Mesin Indonesia International Journal of Innovation in Mechanical Engineering and Advanced Materials International Journal of Renewable Energy Development
Nelwan, Leopold Oscar
Departemen Teknik Mesin Dan Biosistem, Fakultas Teknologi Pertanian, Institut Pertanian Bogor, Kampus IPB Dramaga, Bogor, 16680
Aerospace Engineering Agriculture, Biological Sciences & Forestry Automotive Engineering Chemistry Control & Systems Engineering Earth & Planetary Sciences Electrical & Electronics Engineering Energy Engineering Environmental Science Industrial & Manufacturing Engineering Materials Science & Nanotechnology Mechanical Engineering

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Design and Development of a Web-Based Thermal Application for Vapor Compression Refrigeration Systems Ratu Yanra Dewi; Muhamad Yulianto; Mohamad Solahudin; Leopold Oscar Nelwan; Ida Afriliana; Roni Darpono; N Nasruddin
Jurnal Teknik Pertanian Lampung (Journal of Agricultural Engineering) Vol. 15 No. 1 (2026): February 2026
Publisher : The University of Lampung

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.23960/jtepl.v15i1.19-32

Abstract

The growth of the global food industry has led to an increased demand for cold storage systems to maintain product quality. Cold storage systems based on the vapor compression cycle offer high energy efficiency. However, their design involves multiple stages, ranging from cooling load calculations to prototype development for performance evaluation. This study integrates digital twin–based thermal simulation with Life Cycle Climate Performance (LCCP) analysis into a single web-based platform, namely THE POCI, for cold storage design. The application allows system design, performance calculation, and estimation of the system emission. The development process followed the System Development Life Cycle (SDLC) methodology. Functional testing was conducted using Black-box Testing, while user evaluation was performed using the System Usability Scale (SUS). The results show that all modules provide the expected information and can be used effectively. Model validation against experimental data resulted in Mean Absolute Percentage Error (MAPE) values of 11% for compressor power, 17% for cooling capacity, and 14% for the coefficient of performance (COP). User evaluation involving 47 respondents across the four modules yielded a SUS score of 64.41, indicating that the application is well accepted and has an adequate level of usability.
Design and Performance Evaluation of an IoT-Based Automatic Airflow Control System for a PV/T Solar Dryer with Silica Gel Adsorption Heat Storage Putri Arsyafdini Oktavionry; Leopold Oscar Nelwan; I Dewa Made Subrata
Jurnal Teknik Pertanian Lampung (Journal of Agricultural Engineering) Vol. 15 No. 1 (2026): February 2026
Publisher : The University of Lampung

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.23960/jtepl.v15i1.153-163

Abstract

Solar energy is one of the most promising renewable energy sources, yet solar drying operating costs often remain prohibitive for small-scale farming. This research aims to design and evaluate the performance of an automated air flow control system for a PV/T collector integrated with an adsorption channel. The methodology focuses on developing a real-time monitoring and control logic based on environmental parameters. The system utilizes a microcontroller-based unit for data acquisition of temperature and humidity, coupled with a high-torque motor actuation system to regulate valve positioning between the collector and the desiccant unit. Results indicate that the control system manages air distribution effectively across a temperature control range of 40 °C to 4 3°C. The system demonstrated high responsiveness with a mechanical actuation speed of 3 seconds for a full 90-degree valve rotation. During the adsorption phase, the silica gel's moisture content rose from 23.57% to 27.38%. Furthermore, the silica gel adsorption unit contributed to thermal stability by maintaining a temperature gradient of 3-7 °C between the plenum and the environment, effectively recycling adsorption heat to enhance the drying air temperature even during low solar radiation.
Demineralization of Silica-Rich Agar Processing Residues via Hydrofluoric Acid Leaching for Organic Fraction Enrichment Andi Firdaus Sudarma; Edy Hartulistiyoso; Y. Aris Purwanto; Leopold Oscar Nelwan; Obie Farobie; Hendri; Harri Junaedi; Edy Herianto Majlan
International Journal of Innovation in Mechanical Engineering and Advanced Materials Vol. 8 No. 2 (2026)
Publisher : Universitas Mercu Buana

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.22441/ijimeam.v8i2.38546

Abstract

Agar solid waste (ASW) is a silica-rich industrial residue generated during agar extraction that contains organic residue mixed with mineral filtration aids such as Celite (diatomaceous earth) and perlite. Its high ash content and low organic fraction limit its direct utilization as a biomass-derived fuel. This study investigated hydrofluoric acid (HF) leaching as a demineralization pretreatment to reduce silica-rich minerals and improve the physicochemical quality of ASW. Two ASW samples obtained from different agar-processing plants, namely ASW-Celite (contain Celite) and ASW-Perlite (contain perlite), were treated using 10 wt% HF at a solid-to-liquid ratio of approximately 1:12. The treated samples were characterized using XRF, ICP-MS, FTIR, ultimate analysis, and proximate analysis. HF leaching caused substantial mass reduction, with solid yields of 24.99% for ASW-Celite-HF and 48.9% for ASW-Perlite-HF. Ash content decreased from 85.84 to 44.99 wt% in ASW-Celite and from 77.10 to 24.83 wt% in ASW-Perlite. XRF analysis confirmed significant silica removal, particularly in ASW-Celite, where SiO₂ decreased from 96.94 to 21.30%. ICP-MS further showed the reduction of several ash-forming and environmentally relevant elements, including Cr, Ni, Cu, Zn, Cd, P, S, Cl, Mn, and Fe. HF treatment also enriched the organic fraction, increasing carbon content from 4.69 to 12.52 wt% in ASW-Celite and from 9.83 to 16.10 wt% in ASW-Perlite. The HHV of ASW-Celite improved from 1.91 to 6.52 MJ/kg, whereas ASW-Perlite decreased from 4.80 to 3.19 MJ/kg due to its high oxygen content after treatment. These findings demonstrate that HF leaching effectively reduces silica-rich minerals in ASW, although further deoxygenation is required to improve its fuel quality for bioenergy applications.
Co-Authors Achmad Fitrah Maulidin Ali Usman, Ali Andi Firdaus Sudarma Bandul Suratmo Budi Rahardjo Chandra Gupta Damawidjaya Biksono Darmawati, Emmy - Devi Tanggasari Dwi Setyaningsih Dyah Wulandani Dziyad Dzulfansyah Edy Hartulistiyoso Edy Herianto Majlan Eko Heri Purwanto Emmy Darmawati Erlanda Augupta Pane Harri Junaedi Hayatri Sali Setia Hendri Herry Suhardiyanto I Dewa Made Subrata I Nengah Suastawa I Wayan Astika I Wayan Budiastra Ida Afriliana Irwansyah Irwansyah Kudang Boro Seminar M Ridwan Dwi Astanto Mila Siti Amalia Mohamad Solahudin Mohammad Aftaf Muhajir Muhamad Yulianto Muhamad Yulianto Muhamad Yulianto N Nasruddin Nurul Choerunnisa Obie Farobie Omil Charmyn Chatib Putri Arsyafdini Oktavionry Putri Ayu Ira Distriani Ranti - Ranti Ranti, Ranti - Ratu Yanra Dewi Rokhani Hasbullah Roni Darpono Rustam Efendi Samsudin Samsudin Sigit Triwahyudi Sofyan Sjaf Sri Endah Agustina Sulikah . Sutrisno . Syahputra, Sufri Yanto Tamaria Panggabean Tineke Mandang Tri Yulni Tya Lestari Wawan Hermawan Winny Purnama Sari Y. Aris Purwanto Yogi Sirodz Gaos Yusnita Oni Napitu