High Energy Efficient System Design for Incubation Process and Cooling of Yoghurt

Öz

Food processing studies are important for both efficient use of energy and to obtain quality products. Yoghurt is a dairy product which consumes widely. Yoghurt producing facilities consumes high energy and run at low efficiency due to their traditional production methods. In order to produce quality yoghurt, pasteurized milk should be kept at 42-45 oC for 3-5 hours depending on the yeast type, this process called as incubation. After the incubation process, produced yoghurt must be cooled down to 20 oC in two hours depending on the package size of yoghurt. In conventional yoghurt production facilities, required heating and cooling are applied independently and this approach causes high energy consumptions, waste heat and the inefficient use of energy. In this study, a combined system consisting of a heat pump and a heat storage unit which is capable of the simultaneously heating and/or cooling application independently of each other is designed to ensure higher energy performance and efficiency. Thus, the required energy for heat transfer from the evaporator and cooling after the incubation process was ensured from the stored ice and, independently of the weight of the product, 64/68 units of energy (depending of refrigerant) were gained for each 100 units of required heating energy.The coefficient of performance (COP) of the system using R410a and R134a for heating, cooling and dual operation modes were calculated as 2.83, 1.83, 4.66 and 3.16, 2.16, 5.31, respectively. Energy costs for heat pump and conventional natural gas-fuel-oil boilers were compared. High energy efficiency and low energy consumption have been provided with the presented design, and suggestions for use for production facilities are given.

Anahtar Kelimeler

• Incubation of yoghurt,energy efficiency,heating,cooling

Kaynakça

1. [1] Our World in Data. World Population Growth. [online] Available at: https://ourworldindata.org/world-population-growth [2018].
2. [2] Sorgüven, E. and Özilgen, M. “Energy utilization, carbon dioxide emission, and exergy loss in flavored yogurt production process”. Energy, 40(1):214-225, (2012).
3. [3] Xu, T. and Flapper, J. “Energy use and implications for efficiency strategies in global fluid-milk processing industry” Energy Policy, 37(12):5334-5341, (2009).
4. [4] Özilgen, M. “Energy utilization and carbon dioxide emission during production of snacks” Journal of Cleaner Production, 112:2601-2612, (2016).
5. [5] Foster, C., Green K., Bleda, M., Dewick, P., Evans, B., Flynn A., Mylan, J. “Environmental Impacts of Food Production and Consumption”, A report to the Department for Environment, Food and Rural Affairs. Manchester Business School. Defra, London, (2006).
6. [6] Tamime, A. Y., and Robinson, R.K., “Yoghurt Science and Technology”, Second edition, Woodhead Publishing Ltd., ISBN 1 85573 399 4, England, (1999).
7. [7] Dewick, P., Foster, C. and Green, K. “Technological Change and the Environmental Impacts of Food Production and Consumption, The Case of the UK Yogurt Industry”, Journal of Industrial Ecology, 11(3): 133-146, (2007).
8. [8] Abuşka, M. ve Doğan, H. “Endüstriyel Tip Isı Pompalı Kurutucuda Çekirdeksiz Üzümün Kurutulması”, Politeknik Dergisi, 13 (4): 271-279, (2010).

9. [9] Aktaş, M. “Güneş Enerjisi ve Isı Pompası Destekli Bir Kurutucuda Kırmızıbiber Kurutulmasının Deneysel İncelenmesi, Politeknik Dergisi, 13(1):1-6, (2010).
10. [10] Aktaş, M., Taşeri, L., Şevik, S., Gülcü, M., Seçkin, G.U, Dolgun E.C. “Heat pump drying of grape pomace: Performance and product quality analysis”, Drying Technology, https://doi.org/10.1080/07373937.2018.1536983, (2019).
11. [11] Bianco, V., Scarpa, F., Tagliafico, L.A. “Estimation of primary energy savings by using heat pumps for heating purposes in the residential sector”, Applied Thermal Engineering, 114 : 938–947, (2017).
12. [12] Deng, J., Wei, Q., Liang, M., He, S., Zhang, H., “Does heat pumps perform energy efficiently as we expected: Field tests and evaluations on various kinds of heat pump systems for space heating”, Energy & Buildings, 182: 172–186, (2019).
13. [13] Bai, L., Liu, X., He, M., “A new thermodynamic cycle of heat pump relying on excess enthalpy changing”, Applied Thermal Engineering, 150: 605–611, (2019).
14. [14] Byrne, P., Miriel, J., Lenat, Y. “Design and simulation of a heat pump for simultaneous heating and cooling using HFC or CO2 as a working fluid”, International Journal of Refrigeration, 32:1711-1723, (2009).
15. [15] Dongellinia, M., Naldia, C., Morinia, G.L., “Annual performances of reversible air source heat pumps for space conditioning”, Energy Procedia, 78 : 1123 – 1128,( 2015).
16. [16] Byrne, P., Ghoubali, R., “Exergy analysis of heat pumps for simultaneous heating and cooling”, Applied Thermal Engineering, 149 : 414–424, (2019).
17. [17] Walstra, P.; Wouters, J.T.M.; Geurts, T.J. “Chapter 22 Fermented milks”, Dairy Science and Technology, CRC Press, DOI: https://doi.org/10.1201/9781420028010, Boca Raton-USA, (2005).
18. [18] Shaker, R.R.; Jumah, R.Y.; Abu-Jdayil, B. “Rheological properties of plain yogurt during coagulation process: Impact of fat content and preheat treatment of milk”, J. Food Eng., 44: 175–180,(2000).
19. [19] Lee, W. and Lucey, J. “Formation and physical properties of yoghurt”, Asian-Australian Journal of Animal Science 23: 1127 – 1136,(2010).
20. [20] Göçer E.M.Ç., Ergin F., Arslan A.A., Küçükçetin A., “Effect of Different Incubation Temperature and Final Incubation pH on Physicochemical and Microbiological Properties of Probiotic Yogurt”, Akademik Gıda, 14(4): 341-350, (2016).
21. [21] Lee, W. and Lucey, J. “Structure and Physical Properties of Yoghurt Gels: Effect of Inoculation Rate and Incubation Temperature”, Journal of Dairy Science, 87: 3153-3164,(2004).
22. [22] Wardani, S.K., Cahyanto, M.N., Rahayu, E.S., Utami, T. “The effect of inoculum size and incubation temperature on cell growth, acid production and curd formation during milk fermentation by Lactobacillus plantarum Dad 13”, International Food Research Journal, 24(3):921-926, (2017).
23. [23] Aswal, P., Shukla, A., and Priyadarshi, S. “Yoghurt: Preparation, Characteristics and Recent Advancements”, An Online International Journal, 1(2) : 32-44, (2012).
24. [24] Yamada, M., Fukusako, S. and Kawanami, T. “Performance analysis on the liquid-ice thermal storage system for optimum operation”, International Journal of Refrigeration, 25(2):267-277, (2002).
25. [25] Mammoli, A., Robinson, M. “Numerical analysis of heat transfer processes in a low-cost, high performance ice storage device for residential applications”, Applied Thermal Engineering 128 : 453–463,(2018).