Article Per Year (5 Year)
p-Index From 2021 - 2026
0.702
P-Index
This Author published in this journals
All Journal Jurnal Sains dan Teknologi
Yolli Fernanda
Department of Mechanical Engineering, Faculty of Engineering, Universitas Negeri Padang
Agriculture, Biological Sciences & Forestry Chemistry Civil Engineering, Building, Construction & Architecture Physics Transportation

Published : 4 Documents Claim Missing Document
Claim Missing Document
Check
Articles

Found 4 Documents
Search

 1 
Analisis Kenyamanan Ruangan Menggunakan Sistem Pendingin Kalor Bawah Tanah (Earth-Air Heat Exchanger) Nikmatul Akbar; Yolli Fernanda; Arwizet K; Andre Kurniawan
Jurnal Sains Dan Teknologi | E-ISSN : 3063-9980 Vol. 3 No. 1 (2026): Juli - September
Publisher : GLOBAL SCIENTS PUBLISHER

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

Abstract

Thermal comfort is a critical factor for room quality in humid tropical climates such as Padang, West Sumatra, where high outdoor temperature and relative humidity make conventional cooling energy-intensive. This study analyses the potential of an Earth-Air Heat Exchanger (EAHE), a passive cooling technology that uses the stable temperature of soil to pre-cool outdoor air before it enters a room. A quantitative experimental-analytical approach was applied to a 9.6 m³ test room equipped with a 10 m long, 3-inch diameter EAHE pipe buried at a depth of 1 m and driven by a blower. Cooling load was estimated using the Carrier method, while air temperature, relative humidity, and air velocity were evaluated against SNI 03-6572-2001. Results show a total room cooling load of 1,210.60 W, dominated by heat gain through the roof (552.42 W) and walls (448.90 W). The EAHE lowered the outdoor air temperature by an average of 2.62°C, with the system effectiveness reaching about 50.5 percent. However, the resulting room air condition, with an average temperature of 29.42°C and relative humidity of 71.7 percent, has not yet fully met the SNI comfort range. These findings indicate that EAHE can meaningfully reduce cooling demand and pre-cool incoming air, but achieving full thermal comfort in a humid tropical climate requires it to be combined with improved building envelope insulation and additional dehumidification strategies.
Analysis of the Use of Sengon Wood Biochar as a Moisture Absorber in Air Conditioning Heru Setiawan; Yolli Fernanda; Arwizet K; Andre Kurniawan
Jurnal Sains Dan Teknologi | E-ISSN : 3063-9980 Vol. 3 No. 2 (2026): Oktober - Desember
Publisher : GLOBAL SCIENTS PUBLISHER

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

Abstract

Kelembapan relatif (relative humidity/RH) yang tinggi menurunkan kenyamanan termal dan meningkatkan beban pendinginan pada sistem pengkondisian udara, sedangkan desikan konvensional seperti silika gel dan zeolit berasal dari mineral dan memerlukan energi besar dalam produksinya. Penelitian ini bertujuan mengevaluasi briket biochar kayu sengon (Falcataria moluccana) sebagai material penyerap kelembapan alternatif untuk pengkondisian udara. Serbuk kayu sengon dikeringkan pada 110 °C selama 7 jam, diayak pada ukuran 18–30 mesh, kemudian dipres panas pada tekanan 30 MPa dengan waktu tahan 10 menit pada temperatur 250, 300, dan 330 °C. Briket dikarakterisasi berdasarkan massa sisa dan densitas, lalu ditempatkan pada ruang uji akrilik yang dilengkapi kipas dan humidifier; temperatur dan RH dicatat setiap 15 menit selama 5 jam 15 menit dan massa briket ditimbang sebelum dan sesudah pengujian. Massa sisa menurun dari 91% pada 250 °C menjadi 74% pada 300 °C dan 36% pada 330 °C, sedangkan densitas berubah secara tidak linier dengan nilai tertinggi 1,855 g/cm³ pada 300 °C. Selama pengujian, RH turun dari 99,2% menjadi 88,3% (penurunan bersih 10,9 poin persentase dengan nilai minimum 80,5%) dan massa gabungan dua briket bertambah 7,90 g (1,46%). Karena tidak ada pengujian kontrol tanpa biochar dan setiap kondisi hanya diwakili satu sampel, temuan ini menunjukkan potensi interaksi biochar sengon dengan uap air udara, bukan kapasitas adsorpsi yang telah terukur. Pengujian berulang dengan kontrol, sensor pada sisi masuk dan keluar aliran udara, serta kajian regenerasi disarankan untuk penelitian lanjutan.
Analysis of Waste Heat Utilization from a Briquette Stove for Electricity Generation Using a Thermoelectric Generator Faisya Alfajri; Yolli Fernanda; Arwizet K; Andre Kurniawan
Jurnal Sains Dan Teknologi | E-ISSN : 3063-9980 Vol. 3 No. 2 (2026): Oktober - Desember
Publisher : GLOBAL SCIENTS PUBLISHER

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

Abstract

Briquette stoves lose much of their combustion heat through the stove wall, although this waste heat can be converted into small-scale electricity using a thermoelectric generator (TEG). This study aimed to analyze the utilization of briquette stove waste heat for electricity generation using TEGs and to evaluate the effect of combustion air velocity on temperature and electrical output. A quantitative experiment used six SP1848-27145 SA TEG modules connected in series and mounted on the outer wall of a carbon steel stove through steel plates, with heatsinks and cooling fans on the cold side. In each test, 1 kg of coconut-shell charcoal briquettes was burned at air velocities of 1, 3, and 5 m/s. Temperatures, voltage, and current were recorded every 5 minutes for 60 minutes, and the power and conversion efficiency were calculated using Fourier’s law. The average temperature difference across the modules was 44.63, 56.04, and 34.61 °C, producing average electrical power of 0.598, 0.823, and 0.474 W at 1, 3, and 5 m/s, respectively, peaking at 1.37 W at 3 m/s. Conversion efficiencies were 0.79%, 0.87%, and 0.81%. The temperature difference correlated positively with voltage and power. An air velocity of 3 m/s gave the best performance among the tested values, whereas 5 m/s reduced the output, attributed to excess air cooling the flame and shortening burning duration. Although the power and efficiency remain low, the system shows that briquette stove waste heat can be harvested as a source of electricity.
Analisis Kualitas Fisik terhadap Nilai Kalor Briket Biomassa Berbahan Limbah Tongkol Jagung tanpa Perekat sebagai Energi Alternatif Rangga Notrifaldi; Yolli Fernanda; Sri Rizki Putri Primandari; Andre Kuriawan
Jurnal Sains Dan Teknologi | E-ISSN : 3063-9980 Vol. 3 No. 2 (2026): Oktober - Desember
Publisher : GLOBAL SCIENTS PUBLISHER

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

Abstract

Corn cob is an abundant agricultural residue in Indonesia that is still underused, and binderless densification offers a route to convert it into a solid fuel. This study examined the physical quality of binderless corn cob briquettes and its relationship with calorific value. Corn cobs were chopped, sieved through a 30-mesh sieve (about 0.595 mm), oven-dried, and hot-pressed (15 g per briquette, 15 min holding time) at 250 and 270 °C under 3, 5, and 10 MPa, producing six briquettes. Appearance, mass yield, density, moisture content, and surface morphology (SEM) were evaluated, while elemental composition (EDS) and calorific value (bomb calorimeter) were determined for the 250 and 270 °C conditions. Briquettes pressed at 5 MPa were sturdy, those at 3 MPa were brittle, and those at 10 MPa showed cracks. Mass yield ranged from 76.53% (250 °C, 3 MPa) to 36.60% (270 °C, 10 MPa), density from 0.855 to 1.202 g/cm³, and moisture content from 3.36 to 3.64%. Calorific value increased from 18,286 J/g at 250 °C to 20,746 J/g at 270 °C (+13.45%), accompanied by an increase in surface carbon from 48.48% to 51.47% and a decrease in oxygen from 44.68% to 42.23%. The higher calorific value was not accompanied by higher density or lower moisture content. Because each condition was represented by a single briquette and calorific value was measured at two temperatures only, these results indicate trends rather than statistically tested relationships; replicated tests are recommended.
Co-Authors Andre Kuriawan Andre Kurniawan Arwizet K Faisya Alfajri Heru Setiawan Nikmatul Akbar Rangga Notrifaldi Sri Rizki Putri Primandari