Numerical Analysis of Air Flow in an Industrial Refrigeration System and Its Effect on Energy Consumption

Abstract

Refrigerated display cabinets as a type of cooling system is preferable commonly in food shops and grocery store to prevent foods from warm air. They do not have much more efficient compared to the cabinets with glass doors because of the interactions between air curtain. This paper presents experimental and numerical methods to seek energy performance of the horizontal refrigerated display cabinets in terms of design parameters. Two geometry with/without airfoil were designed and evaluated the effects of discharge velocity to create more efficient air curtain. 2D Computational Fluid Dynamics (CFD) model was performed to assess the effect of discharge flow on the cooling load performance of the horizontal display cabinet. The results showed that the airfoil design has increased the efficiency of the air curtain with achieving a more effective air curtain, resulted in mitigation of the ambient warm air infiltration into the cabinet. The return air temperature of the cabinet with airfoil decreased from 272.45 K to 270.62 K compared to the one without airfoil due to more effective air curtain. In this way, the cooling capacity of the refrigeration system has been decreased by 3.82% with airfoil usage. It is also concluded that the air temperature inside the cabinet and the cooling capacity have been decreased by 3.5°C and 2.82%, respectively when Case 7 for used the new type airfoil and Case 1 with the same air velocity are compared.

Keywords

• Refrigeration
• Energy efficiency
• Display cabinet

References

1. [1] Commission Regulation (EU) 2019/2024 of 1 October 2019 laying down ecodesign requirements for refrigerating appliances with a direct sales function pursuant to Directive 2009/125/EC of the European Parliament and of the Council. (2019, 1 October). Office Journal of the Europian Union (L 315).
2. [2] Doğrudan Satış İşlevli Soğutma Cihazlarının Çevreye Duyarlı Tasarım Gerekliliklerine Dair Tebliğ (2019/2024/Ab) (Sgm: 2021/9) (2021, 25 Mart). Resmi Gazete (Sayı 31434).
3. [3] Florlu Sera Gazlarına İlişkin Yönetmelik (2018, 4 Ocak). Resmi Gazete (Sayı 30291).
4. [4] Rossetti, A., Minetto, S., and Marinetti, S., “Numerical modelling and validation of the air flow maldistribution in the cooling duct of a horizontal display cabinet”, Applied Thermal Engineering, 87: 24-33, (2015).
5. [5] Sun, J., Tsamos, K.M., and Tassou, S.A., “CFD comparisons of open-type refrigerated display cabinets with/without air guiding strips”, Energy Procedia, 123: 54-61, (2017).
6. [6] Cui, J., and Wang, S., “Application of CFD in evaluation and energy-efficient design of air curtains for horizontal refrigerated display cases”, International Journal of Thermal Sciences, 43(10): 993-1002, (2004).
7. [7] Wu, Y., Xie, G., Chen, Z., Niu, L., and Sun, D., “An investigation on flowing patterns of the airflow and its characteristics of heat and mass transfer in an island open display cabinet with goods”, Applied Thermal Engineering, 24(13): 1945-1957, (2004).
8. [8] Gonçalves, J.C., Costa, J.J., Figueiredo, A.R., and Lopes, A.M.G., “CFD modelling of aerodynamic sealing by vertical and horizontal air curtains”, Energy and Buildings, 52: 153-160, (2012).

9. [9] Cortella G., “CFD -aided retail cabinets design”, Computers and Electronics in Agriculture, 34(1-3): 43-66, (2002).
10. [10] Hadawey, A.F., Jaber, T.J., Ghaffar, W.A., and Hasan, A.H.A.M, “Air Curtain Design Optimization of Refrigerated Vertical Display Cabinet using CFD”, International Journal of Scientific Engineering and Technology, 1(4): 76-88, (2012).
11. [11] Gaspar, P.D., Gonçalves, L.C.C., and Pitarma, R.A., “Experimental analysis of the thermal entrainment factor of air curtains in vertical open display cabinets for different ambient air conditions”, Applied Thermal Engineering, 31(5): 961-969, (2011).
12. [12] Field, B.S., and Loth, E., “Entrainment of refrigerated air curtains down a wall”, Experimental Thermal and Fluid Science, 30(3): 175-184, (2006).
13. [13] Cao, Z., Gu, B., Han, H., and Mills, G., “Application of an effective strategy for optimizing the design of air curtains for open vertical refrigerated display cases”, International Journal of Thermal Sciences, 49(6): 976-983, (2010).
14. [14] Moureh, J., and Yataghene, M., “Numerical and experimental investigations on jet characteristics and airflow patterns related to an air curtain subjected to external lateral flow”, International Journal of Refrigeration, 67: 355-372, (2016).
15. [15] Çengel Y.A., and Cimbala J.M., Fluid Mechanics Fundamentals and Applications 2 rd ed., Palme, Ankara, 468, (2015).
16. [16] Yamankaradeniz R., Horuz İ., Coşkun S., Kaynaklı Ö., and Yamankaradeniz N., Soğutma Tekniği ve Isı Pompası Uygulamaları 4th Edition , Dora, Bursa, 30-32, (2017).
17. [17] Sovacool B.K., “Valuing the greenhouse gas emissions from nuclear power: A critical survey”, Energy Policy, 36(8): 2950-2963, (2008).
18. [18] Tripathi R., Tiwari G.N., and Dwivedi V.K., “Overall energy, exergy and carbon credit analysis of N partially covered photovoltaic thermal (PVT) concentrating collector connected in series”, Solar Energy, 136: 260-267, (2016).
19. [19] 2019/2018 of 11 March 2019 supplementing regulation (EU) 2017/1369 of the european parliament and of the council with regard to energy labelling of refrigerating appliances with a direct sales function, Official Journal of the European Union, (2019).
20. [20] Balkan Ç., and Kaynaklı Ö., “Bir açık tip çok raflı soğutuculu teşhir dolabında tasarım parametrelerinin HAD üzerinde incelenmesi”, IV. Uluslararası Katılımlı Anadolu Enerji Sempozyumu, Edirne, 1582-1591, (2018).
21. [21] Çalışkan S., Altunok T., Başkaya Ş., and Güngüneş H.M., “Hava perdeli bir ticari soğutma kabininin sayısal analizi” Gazi University Journal of Engineering and Architecture, 26(2): 415-425, (2011).