A simple demand-side management solution for a typical compressed-air system at a South African gold mine

 

 

Leon Liebenberg; Douglas Velleman; Walter Booysen

Centre for Research and Continued Engineering Development (CRCED), North-West University, Pretoria. Consultants to TEMM International (Pty) Ltd and MCI (Pty) Ltd

 

 

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ABSTRACT

Once designed, mine compressed-air systems tend to operate at peak levels throughout the life of the mine, despite there being significant periods when this air quantity is not required. This is mainly due to lack of appropriate compressor controls. Consequently, such compressed-air systems are inefficient and wasteful. A compressed-air system at a South African gold mine was retrofitted with an automatic compressor control system featuring compressor cascading and pressure bandwidth control. The goal was to implement a simple demand-side management (DSM) strategy to afford meaningful electrical energy savings. The automatic control strategy realised a saving of 1.25 MW (on a baseline of 7.22 MW) during Eskom's evening peak demand window. This represents a reduction of 17.3% in electrical power consumption during the evening peak period, and savings of nearly R2.9 million per year.

Keywords: demand-side management, compressed-air systems, gold mines

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Full text available only in PDF format.

 

 

References

Ashok, S., and Banerjee, R., (1995). Load management - the role of the power utility. Pattern Recognition, 28(10): 1493-1497.         [ Links ]

Aegerter, R., (1999). Compressed-air system optimization. Proceedings of the 21st National Industrial Energy Technology Conference, Houston, TX, May 12-13.         [ Links ]

Auffhammer, M., Blumstein, C., and Fowlie, M., (2007). Demand-side management and energy efficiency revisited. Centre for the Study of Energy Markets, University of California Energy Institute, CSEM WP 165r, April.         [ Links ]

Bloch, H., (2006). A practical guide to compressor technology. New York: Wiley-Interscience.         [ Links ]

CAC, (2002). Compressed Air Challenge: Guidelines for selecting a compressed air system service provider and levels of analysis of compressed air systems. Available at http://www.compressedairchallenge.org (accessed 18 Nov. 2011).         [ Links ]

CEA, (2007). Guide book: Compressed-air energy efficiency reference guide book. Canada: CEA Technologies.         [ Links ]

Christina, G., and Worrell, E., (2005). Energy efficiency improvement and cost saving opportunities for the vehicle assembly industry. LBNL-50939.         [ Links ]

Cohen, H., Rogers, G.F.C., and Saravanamuttoo, H.I.H., (1987). Gas turbine theory (3rd edition). Longman Scientific & Technical, London.         [ Links ]

D'Antonio, M., Epstein, G., Moray, S., Schmidt, C., (2005). Compressed-air load reduction approaches and innovations. Proceedings of the 27th Industrial Energy Pechnology Conference, New Orleans, LA, May 10-13.         [ Links ]

Da La Vergne, J.N., (2003). Hard Rock Miner's Handbook, 3rd ed. Ontario: Mcintosh Engineering, p. 181.         [ Links ]

DeWitte, M, and Boesmans, B., (2009). Activity Report: From innovation to operational assistance. Laborelec. http://www.laborelec.be/pages_files/AR2009.pdf (accessed 14 March 2011).         [ Links ]

Eskom, (2009). The Energy Efficiency Series: Towards and energy efficient mining sector. Available from http://www.eskom.co.za/dsm (Accessed March 2011).         [ Links ]

Eskom, (2010). Mega Flex tariffs, http://www.eskom.co.za/live/ content.php?Category_ID=287 (Accessed June 2010).         [ Links ]

Eskom, (2009). How are DSM initiatives costed? http://www.eskom.co.za (Accessed May 2010).         [ Links ]

Fawkes, H., (2005). Energy efficiency in South African industry. Journal of Energy in South Africa, 16(4): 18-25.         [ Links ]

Fink, D.A., Cumpsty, N.A., and Greitzer, E.M., (1992). Surge dynamics in a free-spool centrifugal compressor. ASME J. Turbomachinery, 114(2): 321-332.         [ Links ]

Gellings, C.W., and Parmenter, K.E., (2007). Distributed generation and demand-side management. In: Handbook of Energy Efficiency and Demand-Side Management (eds. F. Kreith, D. Y. Goswami), New York: CRC Press, pp. 5.33-5.53.         [ Links ]

Gillingham, K., Newell, R., and Palmer, K., (2006). Energy efficiency policies: a retrospective examination. Annu. Rev. Environ. Resour., 31: 161-192.         [ Links ]

Gomes, A., Martins-Gomes, A., and Figueiredo, R., (1999). Simulation-based assessment of electric load management programs. Int. J. Energy Res., 23: 169-181.         [ Links ]

Greitzer, E. M., (1976 a). Surge and Rotating Stall in Axial Flow Compressors, Part I: Theoretical Compression System Model, J. Engineering for Power, (98): 190-198.         [ Links ]

Greitzer, E. M., (1976 b). Surge and Rotating Stall in Axial Flow Compressors, Part II: Experimental Results and Comparison with Theory, J. Engineering for Power, (98): 199-217.         [ Links ]

Hartman, H.L., Mutmansky, J.M., Ramani, R.V., and Wang, Y.J., (1997). Mine Ventilation and Air Conditioning, 3rd edition. New York: Wiley.         [ Links ]

Hughes, A., Howells, M.I., Trikam, A., Kenny, A.R., and Van Es, D., (2006). A Study of Demand Side Management Potential in South African Industries. Proceedings of the Industrial and Commercial Use of Energy conference, Cape Town.         [ Links ]

Joubert, R., and Liebenberg, L., (2010). Cost- and time efficient DSM on mine compressed-air systems. Proceedings of the Industrial and Commercial Use of Energy conference, Cape Town.         [ Links ]

Kaya, D, Phelan, P, Chau, D., and Sarac, H.I., (2002). Energy conservation in compressed-air systems. International Journal of Energy Research, 26: 837-49.         [ Links ]

Kocsis, C.K., Hall, R., and Hardcastle, S.G., (2003). The integration of mine simulation and ventilation simulation to develop a 'Life Cycle' mine ventilation system. Application of Computers and Operations Research in the Minerals Industries, South African Institute of Mining and Metallurgy, pp. 223-230.         [ Links ]

Koski, M.A., (2002). Compressed-air energy audit, the real story. Energy Engineering, 99(3): 59-70.         [ Links ]

Neser, H., Pelzer, R., and Kleingeld, M., (2008). Energy savings through the automatic control of underground air demand. Proceedings: Industrial and Commercial Use of Energy, Cape Town.         [ Links ]

Nillson, H., (1994). The many faces of demand-side management. Power Engineering Journal, 8(5): 211-217.         [ Links ]

NPCI, (2006). Electrical Energy Equipment: Compressors and compressed-air systems. Energy Efficiency Guide for Industry in Asia. National Productivity Council of India, p. 2.         [ Links ]

Paulus, M., and Borggrefe, FF, (2010). The potential of demand-side management in energy-intensive industries for electricity markets in Germany. Applied Energy, 88(2):432-441.         [ Links ]

Pelzer, R., Mathews, E.H., Le Roux, D.F, and Kleingeld, M., (2008). A new approach to ensure successful implementation of sustainable demand-side management (DSM) in South African mines. Energy, 33(8): 1254-1263.         [ Links ]

Popp, D., Newell, R.G., and Jaffe, A.B., (2009). Energy, the environment, and technological change. NBER Working Paper No. 14832, National Bureau of Economic Research, Cambridge, MA, April.         [ Links ]

Radgen, P. (ed.), (2003). Druckluft Effizient: 'Compressed-air Facts', Fraunhofer ISI, available from http://www.druckluft-effizient.de (accessed 20 March 2011), Oct.         [ Links ]

Redford, S.J., (1994). The rationale for demand-side management. Power Engineering Journal, 8(5): 211-217.         [ Links ]

Risi, J.D., (1995). Energy Savings with Compressed-air. Energy Engineering, 92(6): 49-58.         [ Links ]

Saidur, R., Rahim, N.A., and Hasanuzzaman, M., (2010). A review on compressed-air energy use and energy savings. Renewable and Sustainable Energy Reviews, 14: 1135-1153.         [ Links ]

Schmidt, C., and Kissock, K., (2005). Modelling and Simulation of Air Compressor Energy Use. American Council for an Energy Efficient Economy (ACEEE) Conference, West Point, NY. Available from http://www.aceee.org/proceedings-paper/ss05/panel01/paper13 (accessed 15 March 2011).         [ Links ]

Sioshansi, F.P., (2000). Demand-side management: the third wave. Energy Policy, 23(2): 111-114.         [ Links ]

Strbac, G., (2008). Demand-side management: benefits and challenges. Energy Policy, 36(12): 4419-4426.         [ Links ]

USDoE, (2003). Improving Compressed-air System Performance, a sourcebook for industry. US Department of Energy, Energy Efficiency and Renewable Energy, Washington, D.C., Nov.         [ Links ]

USDoE, (2004). Energy Tips-Compressed-air, Tip Sheet #1, 'Determine the cost of compressed-air for your plant. US Department of Energy, Energy Efficiency and Renewable Energy, Washington, D.C.         [ Links ]

Winkler, H. (ed.), (2006). Energy policies for sustainable development in South Africa; options for the future. Energy Research Centre, University of Cape Town, April.         [ Links ]

Winkler, H., Howells, M., and Baumert, K., (2007). Sustainable development policies and measures: institutional issues and electrical efficiency in South Africa. Climate Policy, 7(3): 212-229.         [ Links ]

Witrant, E., et al., (2010). Wireless ventilation control for large-scale systems: the mining industrial case. Int. J. Robust Nonlinear Control, 20: 226-251.         [ Links ]

 

 

Received 4 April 2011
Revised 25 November 2011