DSpace-CRIS

Now showing 1 - 2 of 2

Some of the metrics are blocked by your
consent settings
Experimental optimization of defrosting duration for enhanced energy efficiency in large-scale ammonia-based tube ice-making systems
(2026-08-01)
Ohnjaikla, Natcha
;
Poungthong, Pongthep
;
Kasayapanand, Nat
This study experimentally investigates the impact of defrosting duration on the operational performance and energy efficiency of an industrial-scale 80-ton-per-day ammonia (NH<inf>3</inf>)-based tube ice-making system with a tube diameter of 38 mm. Experiments were performed under controlled ambient conditions (28 °C dry bulb temperature and 80% relative humidity) with defrosting times of 5, 6, and 7 min. Key performance indicators, including suction and discharge pressures, temperatures, power consumption, cooling capacity, freezing time, ice weight per cycle, and the coefficient of performance (COP), were systematically monitored. Each experiment was repeated three times (n = 3), and the results are reported as mean ± standard deviation. Results indicate that extending defrosting time beyond 5 min increases discharge pressure by up to 9% and discharge temperature by up to 12 °C, leading to a 3.14–9.52% rise in compressor energy consumption. At the same time, cooling capacity decreased by 2.8% (6 min) and 7.1% (7 min), lengthening freezing cycles and reducing daily ice production by 4–10% compared with the 5-minute baseline. Although slightly more ice mass per cycle was achieved with longer defrosts, this advantage was offset by higher energy demand and lower cooling efficiency. The findings underscore the importance of optimizing defrosting duration to achieve an effective balance between energy consumption and production efficiency in industrial ice-making systems. Furthermore, thermo-hydraulic evaluation using SEC confirms that a 5-minute defrost duration optimally balances energy efficiency and production capacity, providing a validated experimental benchmark for defrost optimization in large-scale ammonia-based tube ice systems.
Some of the metrics are blocked by your
consent settings
Energy-Efficient Paddy Rice Dehumidification using a Thermosyphon System
(2025-07-01)
Poungthong, Pongthep
;
Promprasansuk, Sookjai
;
Tanaratchat, Vikorn
;
Promchai, Anuruk
;
Ritthong, Wirote
Efficient post-harvest drying is vital to maintain paddy rice quality, prevent spoilage, and extend storage life. This study presents a thermosyphon-based dehumidification system, tested with hot air and hot water heating at 60, 70, and 80 °C. The system includes a cylindrical drying chamber with automated controls for higher efficiency. Performance was evaluated using drying time, energy efficiency, and specific energy consumption (SEC). Results showed the system reduced paddy rice moisture from 26.65% to the target 14% (d.b.). Drying times with hot air were 128, 76, and 50 hours, while hot water required 104, 62, and 42 hours at 60, 70, and 80 °C, respectively. Hot water at 80°C achieved the fastest drying, completing the process in 42 hours. Energy performance analysis revealed the lowest SEC of 89.05 kWh/kg water for hot water at 80 °C, whereas hot air at 60 °C recorded the highest SEC of 1,204 kWh/kgwate. Overall, the thermosyphon system demonstrated strong potential for balancing drying speed and energy use. The study supports thermosyphon-based drying as a scalable, energy-efficient solution for post-harvest rice management, with hot water offering both rapid drying and efficiency

KMITL

Browse

Filters

Settings

Sort By

Results per page

Search Results