EXPERIMENTAL ANALYSIS OF THE AIR DEFROST PROCESS IN AN INDUSTRIAL COOLING SYSTEM

Year 2020, Issue: 045, 143 - 157, 31.12.2020

Süleyman Erten Meltem Koşan Furkan İşgen , Mustafa Aktaş

Abstract

Keeping product temperatures homogeneous is an important problem in defrosted industrial coolers. In this study, it is aimed to obtain findings that will shed light on researchers and producers by analyzing the defrosting process of the industrial cooler. For these reasons, the system was designed using R290 (propane), a new generation refrigerant with a single evaporator, double condenser and double compressor, in order to ensure homogeneous cooling. By keeping the cooled products in the range of – 1 ℃ and +5 ℃ as required by the standard, during the experiment, temperature-pressure measurements of the refrigerated products and cooling system equipment were taken from certain points every minute and test data were recorded. The average temperature and relative humidity values measured minute of the environment where the experimental setup is located was calculated as 25℃ ±1℃ and 60%±0.02%, respectively. During the experiment, eight defrost operations were performed, and it was observed that the average temperature values taken from the products during the 24 hours during defrosting changed to 3.07℃. During the experiment, the highest and lowest temperatures of the cooled products were measured as 4.22℃ and 2.02℃. Increased product temperatures and cooling stopped during defrosting increased the power consumption in the system. In order to observe the effect of the power consumption on system performance, COP values after each defrost time were calculated as 2.31, 2.30, 2.29, 2.60, 3.36, 3.29, 3.30, 3.49, respectively. When the defrost process of cooling system analyzed, it was seen that the products were successfully cooled at desired temperature ranges in the scope of TS EN ISO 23953-2.

Keywords

Defrost, Industrial Cooling, Efficiency, Heat Pump

References

• [1] Qu, M., Xia, L., Deng, S., & Jiang, Y. (2012). An experimental investigation on reverse-cycle defrosting performance for an air source heat pump using an electronic expansion valve. Applied Energy, 97, 327–333.
• [2] Kwak, K. and Bai, C., (2010), A study on the performance enhancement of heat pump using electric heater under the frosting condition: Heat pump under frosting condition, Applied Thermal Engineering, 30(6-7), 539–543.
• [3] Zhu, J.H., Sun, Y.Y., Wang, W., Deng, S.M., Ge, Y.J. and Li, L.T., (2015), Developing a new frosting map to guide defrosting control for air-source heat pump units, Applied Thermal Engineering, 90, 782-791.
• [4] Guo, X.M., Chen, Y.G., Wang, W.H. and Chen, C.Z, (2008), Experimental study on frost growth and dynamic performance of air source heat pump system, Applied Thermal Engineering, 28 (17-18), 2267–2278.
• [5] Wang, W., Zhang, S., Li, Z., Sun, Y., Deng, S. and Wu, X., (2019), Determination of the optimal defrosting initiating time point for an ASHP unit based on the minimum loss coefficient in the nominal output heating energy, Energy, 191, 116505.
• [6] Hewitta, N. and Huang, M.J., (2008), Defrost cycle performance for a circular shape evaporator air source heat pump, International Journal of Refrigeration, 31, 444–452.
• [7] Byun, J.S., Lee, J. and Jeon, C.D., (2008), Frost retardation of an air-source heat pump by the hot gas bypass method, International Journal of Refrigeration, 31, 328–334.
• [8] Egelandsdal, B., Abie, S.M., Bjarnadottir, S., Zhu, H., Kolstad, H., Bjerke, F., Martinsen, O.G., Mason. A. and Münch, D., (2019), Detectability of the degree of freeze damage in meat depends on analytic-tool selection. Meat Science, 152, 8-19.
• [9] Long, Z., Jiankai, D., Yiqiang, J. and Yang, Y., (2014), A novel defrosting method using heat energy dissipated by the compressor of an air source heat pump, Applied Energy, 133, 101–111.
• [10] Liu, Z., Li, A., Wang, Q., Chi, Y. and Zhang, L., (2017), Experimental study on a new type of thermal storage defrosting system for frost-free household refrigerators, Applied Thermal Engineering, 118, 256–265.
• [11] Song, M., Pan, D., Li, N. and Deng, S., (2015), An experimental study on the negative effects of downwards flow of the melted frost over a multi-circuit outdoor coil in an air source heat pump during reverse cycle defrosting, Applied Energy, 138, 598–604.
• [12] Mengjie, S., Deng, S., Pan, D. and Ning, M., (2014), An experimental study on the effects of downwards flowing of melted frost over a vertical multi-circuit outdoor coil in an air source heat pump on defrosting performance during reverse cycle defrosting, Applied Thermal Engineering, 67(1-2), 258–265.
• [13] Green T, Luckmann E, The secret behind danfoss adaptive defrost (BE327320541044en-000101). Danfoss: 2020.
• [14] Aktaş, M., Koşan, M., Arslan, E. and Tuncer, A.D., (2019), Designing a novel solar-assisted heat pump system with modification of a thermal energy storage unit, Proc IMechE Part A: J Power and Energy, 233(5): 588-603.
• [15] Tuncer, A.D., Mavuş, R., Gökçe, C., Koşan, M. and Aktaş, M., (2019), Efficient Energy Systems Models for Sustainable Food Processing, Turkish Journal of Agriculture: Food Science and Technology, 7, 1138-1145.
• [16] Koşan, M., Demirtaş, M., Aktaş, M. and Dişli, E., (2020), Performance analyses of sustainable PV/T assisted heat pump drying system, Solar Energy, 199: 657-672.
• [17] Caner, M., Duman, N., Buyruk, E. and Kılınç F., (2019), Performance Analysİs of Horizontal Ground Source Heat Pump System in Sıvas, Journal of Science and Technology of Dumlupinar University, 42, 47-53.
• [18] Cengel, Y.A. and Boles, M.A., (2014), Thermodynamics: An Engineering Approach, McGraw-HillHigher Education.