http://invotek.ppj.unp.ac.id/index.php/invotek/issue/feed 2025-11-16T13:53:53+00:00 Dr. Dori Yuvenda doriyuvenda@ft.unp.ac.id Open Journal Systems <p>INVOTEK:&nbsp;<em>Jurnal Inovasi Vokasional dan Teknologi</em>&nbsp;is a peer reviewed journal that publishes twice a year&nbsp; (April and October) on articles concerning Technical &amp; Vocational Education and Training (TVET) practices in both the formal and informal sectors and also technology field. &nbsp;It provides an academic forum and scientific research discussion for the cross-disciplinary exchange of insights and ideas regarding value and practices for dissemination. We welcome article submissions from the local and international TVET researchers and practitioners. We strongly welcome research articles and will also consider critical reviews as well as technical reports that can further our understanding of TVET issues and concerns.</p> http://invotek.ppj.unp.ac.id/index.php/invotek/article/view/1271 2025-11-11T23:20:40+00:00 Risfendra Risfendra risfendra@ft.unp.ac.id Ali Basrah Pulungan alibp@ft.unp.ac.id Durain Parmanoan durain.parmanoan@semenpadang.co.id Noval Prayoga novalrvp07@gmail.com

<p>The utilization of waste oil as an alternative cooking fuel is limited by its complex ignition process, which requires preheating to reduce viscosity and ensure stable combustion. Conventional methods, such as burning tissue paper, are unsafe, inefficient, and impractical, hindering broader adoption. This study presents the development of an automatic preheating system for waste oil stoves using an ESP32 microcontroller and HMI with TFT LCD display. The system integrates a thermocouple sensor for accurate real-time temperature monitoring and an automatic cut-off mechanism to halt fuel supply during ignition failure, and includes a buzzer for audible alarms during safety shutdowns to improving operational safety. The ignition sequence employs LPG as a preheater before automatically switching to waste oil at the optimal temperature, with programmed control of the blower, igniter, and valves. Experimental results showed thermocouple measurement accuracy with an average error of 4% and high reliability in fuel transition, except at low initial temperatures (31°C and 42°C) where insufficient heating time resulted in high viscosity and transition failure. The safety system effectively prevented hazards, while the HMI provided precise control and monitoring of actuators and combustion conditions. Overall, the proposed system enhances the safety, reliability, and practicality of waste oil stoves and demonstrates potential for industry innovation and renewable energy applications. Nevertheless, the system still requires LPG for the preheating stage and continuous electrical power, which can reduce effectiveness and make it harder to use in mobile or areas without electricity.</p>

2025-11-11T23:20:35+00:00 ##submission.copyrightStatement## http://invotek.ppj.unp.ac.id/index.php/invotek/article/view/1209 2025-11-16T13:53:53+00:00 Devia Gahana Cindi Alfian devia.gahana@ms.itera.ac.id I Gede Pande Naraya Sindhu igede.119170073@student.itera.ac.id Fajar Paundra fajar.paundra@ms.itera.ac.id Dicky Januarizky Silitonga dicky.silitonga@ms.itera.ac.id Andhyka Tyaz Nugraha andhyka.nugraha@ti.itera.ac.id

<p>Indonesia is reducing reliance on fossil fuels by expanding renewable energy, including biomass from rubber-plantation residues and acacia wood. This study evaluates briquettes made from rubber seed shell (RSS) and acacia sawdust (AWS) using 10% tapioca binder, a compaction pressure of 50 kgf cm⁻², and drying at 100 °C for 3 h. Three compositions (RSS:AWS, %wt) were tested: A (50:50), B (70:30), and C (80:20). The best performance was obtained for C (80:20), with moisture 7.40%, volatile matter 9.56%, ash 4.47%, fixed carbon 85.95%, HHV 6,716.88 cal g⁻¹ (28.10 MJ kg⁻¹), and burn rate 0.10 g min⁻¹. All compositions satisfied SNI 01-6235-2000 limits for HHV (≥ 5,000 cal g⁻¹), VM (≤ 15%), and ash (≤ 8%); the moisture criterion (≤ 8%) was met by B and C. For context, SNI 1683:2021 (wood charcoal, not briquettes) imposes stricter thresholds; under these, C is closest to First-Quality ranges, while A and B fall short for several parameters. Overall, increasing the RSS (char) fraction produced briquettes with lower moisture and VM, higher fixed carbon and HHV, and steadier combustion suitable for household fuel.</p>

2025-11-16T13:53:46+00:00 ##submission.copyrightStatement##