Experimental Investigation of the Effect of Internal Losses on the Performance of a Beta-Type Stirling Cooler

Abstract

Stirling engines offer a wide range of applications due to their ability to operate with various energy sources. When mechanical work is applied externally, they can also be used for cooling purposes. Their advantages, such as long lifespan, environmental compatibility, and quiet operation, make them an efficient alternative, particularly in low-power cooling applications. In this study, a beta-type Stirling cooler was experimentally investigated under different charge pressures (1, 2, and 3 bar) and rotational speeds (300–900 rpm) to evaluate its cooling performance. The lowest cold-end temperature was achieved at 1 bar air pressure and 500 rpm, requiring an electrical power input of 1.37 kW. However, deviations from theoretical expectations were observed at higher pressures and speeds. Notably, the cooling performance at 2 bar was lower than at 3 bar, and at 1 bar and 900 rpm, the system exhibited a heating effect. These unexpected results were attributed to increased internal losses caused by factors such as the regenerator-less configuration and the use of air as the working fluid. The findings reveal the complex dependence of loss mechanisms on charge pressure and rotational speed in experimental Stirling cooling systems.

Keywords

• Stirling engine
• Stirling cooler
• Cooling machine
• Internal losses
• Air

İçsel Kayıpların Beta Tipi Bir Stirling Soğutucu Performansı Üzerindeki Etkisinin Deneysel Olarak İncelenmesi

Öz

Stirling motorları, çeşitli enerji kaynaklarıyla çalışabilme yetenekleri sayesinde geniş bir uygulama yelpazesi sunmaktadır. Dışarıdan mekanik iş uygulandığında, soğutma amacıyla da kullanılabilirler. Uzun ömür, çevresel uyumluluk ve sessiz çalışma gibi avantajları sayesinde özellikle düşük güç gerektiren soğutma uygulamalarında verimli bir alternatif oluşturmaktadırlar. Bu çalışmada, beta tipi bir Stirling soğutucu farklı şarj basınçları (1, 2 ve 3 bar) ve devir sayılarında (300–900 rpm) deneysel olarak incelenmiş ve sistemin soğutma performansı değerlendirilmiştir. En düşük soğuk uç sıcaklığı, 1 bar hava basıncında ve 500 rpm’de elde edilmiş olup, bu koşullarda sisteme 1,37 kW elektrik gücü verilmesi gerekmiştir. Ancak artan basınç ve devir sayılarında, teorik beklentilerden sapmalar gözlenmiştir. Özellikle 2 bar basıncındaki performansın 3 bar’a göre daha düşük olduğu; ayrıca, 1 bar basıncında 900 rpm hızda sistemin ısınma eğilimi gösterdiği belirlenmiştir. Bu beklenmedik sonuçlar, rejeneratörsüz sistem tasarımı ve çalışma akışkanı olarak havanın kullanımı gibi etkenlerden kaynaklanan artan içsel kayıplarla ilişkilendirilmiştir. Elde edilen bulgular, deneysel Stirling soğutucu sistemlerinde kayıp mekanizmalarının basınç ve devir sayısına olan karmaşık bağımlılığını ortaya koymaktadır.

Anahtar Kelimeler

• Stirling motoru
• Stirling soğutucu
• Soğutma makinesi
• İçsel kayıplar
• Hava

Kaynakça

1. [1] Özgören, Y. Ö. (2004). Stirling motorlarında ısı kayıplarının azaltılması için termal bariyer kullanımı, Doktora Tezi. Gazi Üniversitesi Fen Bilimleri Enstitüsü, Ankara.
2. [2] Topgül, T. (2022). Design, manufacturing, and thermodynamic analysis of a gamma-type Stirling engine powered by solar energy. Strojniški vestnik - Journal of Mechanical Engineering, 68 (12), 757-770. https://doi.org/10.5545/sv-jme.2022.368
3. [3] Topgül, T., Okur, M., Şahin, F., Çınar, C. (2022). Experimental investigation of the effects of hot-end and cold-end connection on the performance of a gamma type Stirling engine. Engineering Science and Technology, an International Journal, 36, 101152. https://doi.org/10.1016/j.jestch.2022.101152
4. [4] Narasaki, K., Tsunematsu, S., Ootsuka, K., Kyoya, M., Matsumoto, T., Murakami, H., Nakagawa, T. (2004). Development of two-stage Stirling cooler for ASTRO-F. AIP Conference Proceedings, 710, 1428–1435. https://doi.org/10.1063/1.1774835
5. [5] Li, X., Dai, W., Zhang, W., Zhou, R., Xiao, Q., Yu, G., Luo, E., Zhu, S. (2019). A high efficiency free-piston Stirling cooler with 350 W cooling capacity at 80 K. Energy Procedia, 158, 4416–4422. https://doi.org/10.1016/j.egypro.2019.01.775
6. [6] Kim, H. S., Gwak, I. C., Lee, S. H. (2022). Numerical analysis of heat transfer area effect on cooling performance in regenerator of free-piston Stirling cooler. Case Studies in Thermal Engineering, 32, 101875. https://doi.org/10.1016/j.csite.2022.101875
7. [7] Ahmadi, M. H., Ahmadi, M. A., Maleki, A., Pourfayaz, F., Bidi, M., Açıkkalp, E. (2017). Exergetic sustainability evaluation and multi-objective optimization of performance of an irreversible nanoscale Stirling refrigeration cycle operating with Maxwell–Boltzmann gas. Renewable and Sustainable Energy Reviews, 78, 80–92. https://doi.org/10.1016/j.rser.2017.04.097
8. [8] Cui, Y., Qiao, J., Song, B., Wang, X., Yang, Z., Li, H., Dai, W. (2021). Experimental study of a free piston Stirling cooler with wound wire mesh regenerator. Energy, 234, 121287. https://doi.org/10.1016/j.energy.2021.121287

9. [9] Luo, K., Zhang, L., Hu, J., Luo, E., Wu, Z., Sun, Y., Zhou, Y. (2021). Numerical investigation on a heat-driven free-piston thermoacoustic–Stirling refrigeration system with a unique configuration for recovering low-to-medium grade waste heat. International Journal of Refrigeration, 130, 140–149. https://doi.org/10.1016/j.ijrefrig.2021.05.001
10. [10] Guo, D., McGaughey, A. J. H., Gao, J., Fedder, G. K., Lee, M., Yao, S. C. (2013). Multiphysics modeling of a micro-scale Stirling refrigeration system. International Journal of Thermal Sciences, 74, 44–52. https://doi.org/10.1016/j.ijthermalsci.2013.07.003
11. [11] Shigeto, S., Tanaka, K., Sato, Y., Shinozaki, K., Mitani, S. (2021). Evaluation method for effect of active vibration control on cooling performance of Stirling cooler. Cryogenics, 117, 103308. https://doi.org/10.1016/j.cryogenics.2021.103308
12. [12] Cheng, C. H., Huang, C. Y., Yang, H. S. (2019). Development of a 90-K beta type Stirling cooler with rhombic drive mechanism. International Journal of Refrigeration, 98, 388–398. https://doi.org/10.1016/j.ijrefrig.2018.11.027
13. [13] Eid, E. I., Khalaf-Allah, R. A., Soliman, A. M., Easa, A. S. (2019). Performance of a beta Stirling refrigerator with tubular evaporator and condenser having inserted twisted tapes and driven by a solar energy heat engine. Renewable Energy, 135, 1314–1326. https://doi.org/10.1016/j.renene.2018.09.044
14. [14] Chen, X., Shao, S., Xiang, J., Ma, W., Zhang, H. (2018). Experimental investigation on ethane pulsating heat pipe based on Stirling cooler. International Journal of Refrigeration, 88, 506–515. https://doi.org/10.1016/j.ijrefrig.2018.02.020
15. [15] Hu, J. Y., Luo, E. C., Dai, W., Zhang, L. M. (2017). Parameter sensitivity analysis of duplex Stirling coolers. Applied Energy, 190, 1039–1046. http://doi.org/10.1016/j.apenergy.2017.01.022
16. [16] Djetel-Gothe, S., Begot, S., Lanzetta, F., Gavignet, E. (2020). Design, manufacturing and testing of a beta Stirling machine for refrigeration applications. International Journal of Refrigeration, 115, 96–106. https://doi.org/10.1016/j.ijrefrig.2020.03.005
17. [17] Getie, M. Z., Lanzetta, F., Begot, S., Admassu, B. T., Hassen, A. A. (2020). Reversed regenerative Stirling cycle machine for refrigeration application: A review. International Journal of Refrigeration, 118, 173–187. https://doi.org/10.1016/j.ijrefrig.2020.06.007
18. [18] Kline, S. J., McClintock, F. A. (1953). Describing uncertainties in single-sample experiments. Mechanical Engineering, 75(1), 3–8.
19. [19] Karabulut, H., Düzgün, M., Topgül, T. (2023). Nodal thermodynamic analysis of a three-cylinder gamma-type Stirling engine and a conventional gamma-type Stirling engine and performance comparison. Journal of the Faculty of Engineering and Architecture of Gazi University, 38(1), 45-56. https://doi.org/10.17341/gazimmfd.944333