Browsing by Author "Phunapai, Nittalin"

Now showing 1 - 2 of 2
  • Thumbnail Image
    ItemOpen Access
    Experimental Investigation of a locally fabricated low-cost solar parabolic trough in Thailand
    (2022-08-10) Limboonruang, Teerapath; Phunapai, Nittalin; Oyinlola, M. A.
    The current political tensions resulting in sharp increases in oil and gas prices, has further highlighted the need for energy independence by nations. Renewable energy technologies are one way of achieving this, so countries need to focus on developing indigenous technology to harness renewable energy. This study focuses on developing a solar parabolic trough collector for Thailand. Solar energy is a renewable energy source that can be used indefinitely. It will also play an increasingly important role in the future energy structure. Solar Parabolic Trough (SPT) is a device that has a curved shape of cylindrical parabolic. It consists of a shiny surface to reflect sun radiations towards the focal point. There are several factors that can affect the performance of the solar parabolic trough such as the accuracy of the sun model, the reflection of the sun radiation, fluid flow, the heat transfer to fluid and so on. The latter absorbs the incoming radiations and transforms them into thermal energy. This study experimentally investigates the thermal performance of a Solar Parabolic Trough collector with a sun tracking system designed for the Thai contexts. A set of three Solar Parabolic Trough (SPT) were designed and built in Srinakharinwirot University (SWU). Each had a focal length of 300 mm; length 5.1 m. Water was used as the working fluid circulated through a 60 litres water tank. Experiments were run at five (5) different flow rates of 0.5, 1, 2, 3 and 4 litres per minute. Located at the parabolic troughs focal point is the vacuum tube collector which consists of a 10 mm smooth copper tube, enclosed in 47 mm diameter sealed glass tube. Type K Thermocouples were used to measure the temperatures at different points in the fluid and recorded using a data logger, and a sun tracking system was used for controlling stepping motors in the solar parabolic trough. Experiments were run over 5 days between 10:00 – 16:00 Nakhon-Nayok city, Thailand. Solar radiation during the period ranged between 462.60 – 1021.59 W/m2 (average 800.86 W/m2 ) and ambient temperature ranged from 36.54 – 39.17 °C (average 38.48 °C). The results showed that the water flow rate had an inverse relationship with the efficiency of the solar parabolic trough. The flow rate of 0.5 liters per minute resulted in the highest temperature of 56.70 °C and the maximum total rate of heat transfer was 955.65 W. The maximum efficiency was observed to be about 12%. This low efficiency is similar to what has been observed in similar studies. Overall, the study shows promising performance results for the deployment of locally made solar parabolic trough collector in Thailand.
  • Thumbnail Image
    ItemOpen Access
    Optimizing Solar Parabolic Trough Receivers with External Fins: An Experimental Study on Enhancing Heat Transfer and Thermal Efficiency.
    (MDPI, 2023-09-10) Limboonruang, Teerapath; Oyinlola, M. A.; Harmanto, Dani; Bunyawanichakul, Pracha; Phunapai, Nittalin
    Several researchers have shown that the heat transfer performance of solar parabolic trough (SPT) receivers may be improved by increasing their surface area or by adding internal fins to the tubes. Unfortunately, the manufacture of internally finned tubes involves complex processes, resulting in significant cost increases. On the other hand, the addition of external fins to tubes is more technically and economically feasible in a low-resource setting. This study investigates the potential benefits of integrating external fins on the receiver tubes of a low-cost SPT collector system. Experiments were conducted using an SPT system with a focal length of 300 mm and a collector length of 5.1 m, and they were positioned by an automated Sun tracking system. Tests were undertaken using both smooth and externally finned receiver tubes operating at five different water flow rates. The solar receiver with a finned tube was able to provide a maximum water temperature of 59.34 °C compared with that of 56.52 °C for a smooth tube at a flow rate of 0.5 L per minute. The externally finned absorber tube was also found to have a maximum efficiency of 18.20% at an average daily solar intensity of 834.61 W/m2, which is approximately 48% more efficient than the smooth tube. The calculations indicate that the experimental SPT system using finned tubes potentially avoids 0.2726 metric tons of CO2e per year, with finned tubes outperforming smooth tubes by up to 44%. The results show that using externally finned receiver tubes can significantly enhance the thermal performance of SPT collector systems.