Innovative Proposals for Defogging Design Criteria of Refrigerated Display Cabinets

Abstract

Fogging on glass surfaces in refrigerated display cabinets (RDCs) significantly impacts product visibility, energy consumption, air curtain stability, product temperature uniformity, and, indirectly, food safety. Traditionally used, continuously operating anti-sweat heaters and anti-fog coatings require more sustainable solutions due to high operating costs and long-term performance decline. This study investigates the effects of airflow structure, structural design, advanced material properties, and control strategies on fog formation, and proposes design-oriented approaches to prevent fog formation during its development phase. In addition to structural improvements such as composite profiles that reduce thermal bridges, hydrophobic materials, Low-E coating glass, and argon-filled multi-pane glass units, this study proposes optimizing discharge air grille angles to increase air curtain stability, panel perforation strategies based on loading scenarios, and environmentally sensitive control algorithms. The proposed approaches aim to improve energy efficiency while maintaining food safety and ensuring sustainable operational performance. It can be estimated that implementing these proposals will result in energy savings of 5-10%.

Keywords

• Refrigerated display cabinet
• refrigeration
• defogging
• energy efficiency

Teşhir Tipi Soğutucuların Buğu Giderme Tasarım Kriterleri İçin Yenilikçi Öneriler

Öz

Teşhir tipi soğutucularda cam yüzeylerde oluşan buğulanma, ürün görünürlüğünü, enerji tüketimini, hava perdesinin istikrarını, ürün sıcaklığının homojenliğini ve dolaylı olarak gıda güvenliğini önemli ölçüde etkiler. Geleneksel olarak kullanılan, sürekli çalışan buğu önleyici ısıtıcılar ve buğu önleyici kaplamalar, yüksek işletme maliyetleri ve uzun vadeli performans düşüşü nedeniyle daha sürdürülebilir çözümler gerektirmektedir. Bu çalışma, hava akışı yapısı, yapısal tasarım, gelişmiş malzeme özellikleri ve kontrol stratejilerinin buğu oluşumu üzerindeki etkilerini araştırmakta ve geliştirme aşamasında buğu oluşumunu önlemek için tasarım odaklı yaklaşımlar önermektedir. Isı köprülerini azaltan kompozit profiller, hidrofobik malzemeler, Low-E kaplamalı cam ve argon dolgulu çok camlı cam üniteleri gibi yapısal iyileştirmelerin yanı sıra, bu çalışma hava perdesinin stabilitesini artırmak için hava üfleme ızgarası açılarının optimize edilmesini, yükleme senaryolarına dayalı panel delme stratejilerini ve çevreye duyarlı kontrol algoritmalarını önermektedir. Önerilen yaklaşımlar, gıda güvenliğini korurken ve sürdürülebilir operasyonel performansı garanti ederken enerji verimliliğini artırmayı amaçlamaktadır. Bu önerilerin uygulanmasının %5-10 oranında enerji tasarrufu sağlayacağı tahmin edilebilir.

Anahtar Kelimeler

• Teşhir tipi soğutucu
• soğutma
• buğu giderme
• enerji verimliliği

Kaynakça

1. [1] Fricke, B. A., Becker, B. R. (2011). Comparison of vertical display cases: Energy and productivity impacts of glass doors versus open vertical display cases. ASHRAE Transactions, 117(1), 847-58.
2. [2] D’Agaro, P., Croce, G., Cortella, G. (2006). Numerical simulation of glass doors fogging and defogging in refrigerated display cabinets. Applied Thermal Engineering, 26(16), 1927-1934.
3. [3] Purohit, N., Dasgupta, M. S. (2020). Thermal storage material enhanced refrigerated display cabinet. Materials Today: Proceedings, 28(2), 510-514.
4. [4] Bahar, E. M., Erten, S., Aktaş, M. (2021). An Experimental Study Towards Decreasing the Energy Efficiency Index Value in Industrial Refrigerators. Gazi Üniversitesi Fen Bilimleri Dergisi Part C: Tasarım ve Teknoloji, 9(3), 432-445.
5. [5] D’Agaro, P., Croce, G., Suzzi, N. (2021). CFD simulation of anti-fogging coatings performance in refrigerated display cabinets. Journal of Physics: Conference Series, 1868, 012002.
6. [6] Faramarzi, R., Coburn, B., Sarhadian, R. (2010). Anti-sweat heaters in refrigerated display cases. ASHRAE Journal, 52(3), 24-32.
7. [7] Humar, I., Hudomalj, I., Marinšek, A., Umberger, M. (2022). Optimizing the Power Usage of Anti-Sweat Heaters in Glass-Door Refrigerators According to the Dew Point. Energies, 15(13), 4601.
8. [8] U.S. Environmental Protection Agency & Food Marketing Institute. (2010). Energy use and sales productivity of doored and open refrigeration cases. U.S. Environmental Protection Agency.

9. [9] U.S. Department of Energy. (2014). Energy conservation standards for commercial refrigeration equipment (Final rule). Federal Register, 79(125), 32050–32131.
10. [10] Saro, O., De Angelis, A., Cortella, G. (2016). Influence of supply air ceiling diffusers on surface temperature of display cabinet doors and on customers comfort in food stores. CLIMA 2016 - 12th REHVA World Congress, Aalborg, Denmark.
11. [11] Hudomalj, M., Marinšek, A., Umberger, J., Humar, I. (2015). Control of anti-sweat heaters according to dew point. In Proceedings of the International Conference on Refrigeration and Air Conditioning.
12. [12] Dixell Asia Co. Ltd. (2010). Case study of anti-fog film installation to prevent fogging on cabinet glass door.
13. [13] Smale, N. J., Moureh, J., Cortella, G. (2006). A review of numerical models of airflow in refrigerated food applications. International Journal of Refrigeration, 29(6), 911-930.
14. [14] Sabic Global (2014). Price Chopper anti-fog film. Retrieved 10 17.
15. [15] Anti- Fog Presentation. Sunray Windows Films LCC.
16. [16] Howell, R. H., Adams, J. W., Scheatzle, D. G. (2002). Effects of indoor relative humidity on refrigerated display case performance. ASHRAE Transactions, 108(2), 319–327.
17. [17] Foster, A., Hammond, E., Brown, T., Maidment, G., Evans, J. (2018). Technological options for retail refrigeration. Paris International Institute of Refrigeration, London South Bank University.
18. [18] Fricke, B., Bansal, P. K. (2015). Sustainable Retail Refrigeration, Small Commercial Display Cabinets. Wiley, 97-98.
19. [19] Saengsikhiao, P., Taweekun, J., Maliwan, K., Sae-ung, S., Theppaya, T. (2020). Improving Energy Efficiency in the Supermarket by Retrofitting Low E Glass Doors for Open Refrigerated. Journal of Advanced Research in Applied Sciences and Engineering Technology, 20(1), 11-17.
20. [20] Rauss, D., Mitchell, S., Faramarzi, R. (2008). Cool retrofit solutions in refrigerated display cases. Proceedings of the 2008 ACEEE Summer Study on Energy Efficiency in Buildings: Scaling Up: Building Tomorrow's Solutions, 9-233.
21. [21] Hadawey, A. F., Jaber, T. J., Ghaffar, W. A., Hasan, A. H. A. M. (2012). Air Curtain Design Optimization of Refrigerated Vertical Display Cabinetusing CFD. International Journal of Scientific Engineering and Technology, 1(4), 76-88.
22. [22] Austin-Davies, J. (2015). Design of Supermarket Refrigeration Systems. Sustainable Retail Refrigeration, Wiley, 176.