U형 직교 대향류 플라스틱/종이 재질 간접증발소자

• Kim, Nea-Hyun (Department of Mechanical Engineering, Incheon National University)
• Accepted : 2016.11.10
• Published : 2016.11.30
• 37 19

Abstract

In Korea, the summer is hot and humid, and much electricity is consumed for air conditioning. Thus, the simultaneous usage of an indirect evaporative cooler and a common air conditioner could reduce the sensible heat and save electricity. This study developed a U-type cross-counter flow indirect evaporative cooler (IEC) made of plastic and paper. The efficiencies were compared with those of a cross-flow IEC. The specimen was $500mm{\times}500mm{\times}1000mm$. the results show that the indirect evaporation efficiencies of the cross-counter flow sample were 6-21% higher than those of the cross-flow sample. The pressure drops of the cross-counter sample were 51-66% higher. Thermal analysis based on the -NTU method predicted the experimental data within 10%. The electrical energy saved by the use of the cross-counter flow IEC was larger than that of the counter flow IEC, and the difference increases with the velocity. However, the the cross-counter IEC is two times larger than the cross-flow IEC, which may increase the material cost and water usage.

Keywords

Indirect evaporative cooler;Cross-counter;Performance;Paper;Plastic

References

1. Duan, Z., Zhan, C., Zhang, X., Mustafa, M. Zhao, X., Alimohammadisgvand, B. and Hasan, A., "Indirect evaporative cooling: past, present and future potentials," Renew. Sustain. Energy Rev., vol. 16, pp. 6823-6850, 2012. DOI: http://dx.doi.org/10.1016/j.rser.2012.07.007 https://doi.org/10.1016/j.rser.2012.07.007
2. Jaber, S. and Ajib, S., "Evaporative cooling as an efficient system in Mediterranean region," Appl. Therm. Eng., vol. 31, pp. 2590-2596, 2011. DOI: http://dx.doi.org/10.1016/j.applthermaleng.2011.04.026 https://doi.org/10.1016/j.applthermaleng.2011.04.026
3. Caliskan, H., Dincer, I. and Hepbasil, A., "Exergoeconomic enviroecomomic and sustainability analyses of a novel air cooler," Energy Build., vol. 55, pp. 747-756, 2012. DOI: http://dx.doi.org/10.1016/j.enbuild.2012.03.024 https://doi.org/10.1016/j.enbuild.2012.03.024
4. Costello, B. and Finn, D., "Thermal effectiveness characteristics of low approach indirect evaporative cooling systems in buildings," Energy Build., vol. 39, pp. 1235-1243, 2007. DOI: http://dx.doi.org/10.1016/j.enbuild.2007.01.003 https://doi.org/10.1016/j.enbuild.2007.01.003
5. Maheshwari, G. P., Al-Ragom, F. and Suri, R. K., "Energy saving potential of an indirect evaporative cooler," Appl. Energy, vol. 69, pp. 69-76, 2001. DOI: http://dx.doi.org/10.1016/S0306-2619(00)00066-0 https://doi.org/10.1016/S0306-2619(00)00066-0
6. Santamouris, M. and Kolokotsa, D., "Passive cooling dissipation techniques for buildings and other structures: the state of the art," Energy Build., vol. 57, pp. 74-94, 2013. DOI: http://dx.doi.org/10.1016/j.enbuild.2012.11.002 https://doi.org/10.1016/j.enbuild.2012.11.002
7. Watt, J. D. and Brown, W. K., Evaporative No. 0, Air Conditioning Handbook, 3rd ed., The Fairmont Press Inc., 1997.
8. Pescod, D., "A heat exchanger for energy saving in an air conditioning plant," ASHRAE Trans., vol. 85., Pt. 2, pp. 238-251, 1979.
9. Maclaine-Cross, I. L. and Banks, P. J., "A general theory of wet surface heat exchangers and its application to regenerative cooling," J. Heat Transfer, vol. 103, pp. 578-585, 1981. DOI: http://dx.doi.org/10.1115/1.3244505
10. Kettleborough, C. F. and Hsieh, C. S., "The thermal performance of the wet surface plastic plate heat exchanger used in an indirect evaporative cooler," J. Heat Transfer, vol. 105, pp. 366-373, 1983. DOI: http://dx.doi.org/10.1115/1.3245587 https://doi.org/10.1115/1.3245587
11. Parker, R. O. and Treybal, R. E., "The heat mass transfer characteristics of evaporative coolers," Chem. Eng. Prog. Symp. Ser. vol 57, no. 32, pp. 138-149, 1962.
12. Hasan, A. an Siren, K., "Performance investigation of plain and finned tube evaporatively cooled heat exchangers," Appl. Therm. Eng., vol. 23, no. 3, pp. 325-340, 2003. DOI: http://dx.doi.org/10.1016/S1359-4311(02)00194-1 https://doi.org/10.1016/S1359-4311(02)00194-1
13. Zalewski, W. and Gryglaszewski, P. A., "Mathematical model of heat and mass transfer processes in evaporative coolers," Chem. Eng. Process, vol. 36, no. 4, pp. 271-280, 1977. DOI: http://dx.doi.org/10.1016/S0255-2701(97)00006-8
14. Ren, C. and Yang, H., "An analytical model for the heat and mass transfer processes in indirect evaporative cooling with parallel/counter flow configurations," Int. J. Heat Mass Transfer, vol. 49, pp. 617-627, 2006. DOI: http://dx.doi.org/10.1016/j.ijheatmasstransfer.2005.08.019 https://doi.org/10.1016/j.ijheatmasstransfer.2005.08.019
15. Hasan, A., "Going below the wet-bulb temperature by indirect evaporative cooling: Analysis using a modified $\epsilon$-NTU method," Appl. Energy, vol. 89, pp. 237-245, 2012. DOI: http://dx.doi.org/10.1016/j.apenergy.2011.07.005 https://doi.org/10.1016/j.apenergy.2011.07.005
16. Cui, X., Chua, K. J., Islam, M. R. and Yang, W. M., "Fundamental formulation of a modified LMTD method to study indirect evaporative heat exchangers," Energy Conservation Management, vol. 88, pp. 372-381, 2014. DOI: http://dx.doi.org/10.1016/j.enconman.2014.08.056 https://doi.org/10.1016/j.enconman.2014.08.056
17. Chen, Y., Yang, H. and Luo, Y., "Indirect evaporative cooler considering condensation from primary air; Model development and parameter anaysis," Build. Env., vol. 95, pp. 330-345, 2016. DOI: http://dx.doi.org/10.1016/j.buildenv.2015.09.030 https://doi.org/10.1016/j.buildenv.2015.09.030
18. Tejero-Gonzalez, A., Andres-Chicote, M., Velasco -Gomez, E. and Rey-Martinez, F. J., "Influence of constructive parameters on the performance of two indirect evaporative cooler prototypes," Appl. Therm. Eng., vol, 51, pp. 1017-1025, 2013. DOI: http://dx.doi.org/10.1016/j.applthermaleng.2012.10.054 https://doi.org/10.1016/j.applthermaleng.2012.10.054
19. Riangvilaikul, B. and Kumar, S., "An experimental study of a novel dew point evaporative cooling system," Energy Build., vol. 42, pp. 637-644, 2010. DOI: http://dx.doi.org/10.1016/j.enbuild.2010.07.020 https://doi.org/10.1016/j.enbuild.2009.10.034
20. Zhao, X., Liu, S. and Riffat, S. B., "Comparative study of heat and mass exchanging materials for indirect evaporative cooling systems," Build. Environ., vol. 43, no. 11, pp. 1902-1911, 2008. DOI: http://dx.doi.org/10.1016/j.buildenv.2007.11.009 https://doi.org/10.1016/j.buildenv.2007.11.009
21. Kim, N.-H., "Performance comparison between indirect evaporative coolers made of aluminum, plastic or plastic/paper," J. Korea Academia-Industrial Cooperation Society, vol. 16, no. 12, pp. 8165-8175, 2015. DOI: http://dx.doi.org/10.5762/KAIS.2015.16.12.8165 https://doi.org/10.5762/KAIS.2015.16.12.8165
22. KS M 896, Paper and Plate - Measuremint of Water Absorption Rate in Water, 2013.
23. ASHRAE Standard 41.1, Standard Method for Temperature Measurement, ASHRAE, 1986.
24. ASHRAE Standard 41.2, Standard Method for Laboratory Air-Flow Measurement, ASHRAE, 1987.
25. KS C 9306, Air Conditioner, Korean Standard Association, 2010.
26. ASHRAE Standard 143, Method of Test for Rating Indirect Evaporative Coolers, ASHRAE, 2007.
27. Klein S. J. and McClintock, F. A., "The description of uncertainties in a single sample experiments," Mech. Eng, vol. 75, pp. 3-9, 1953.
28. Stevens, R. A., Fernandez, J. and Woolf, J. R., "Mean temperature difference in one, two and three-pass cross flow heat exchangers," Trans. ASME, vol. 79, pp. 287-297, 1957.
29. Kays, W. M. and London, A. L., Compact Heat Exchangers, McGraw-Hill Pub., 1984.
30. Personal communication with Samhwa Ace Co., 2016.