Improved Energy Performance of Air-Conditioning System Using Variable Primary Flow Chilled Water Systems in an Office Building


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The main objective of this on-site study is to use a full-scale HVAC (Heating, Ventilating and Air-Conditioning) system installed in an office building in Taiwan for comparing the power consumption, energy-saving, and CO2 reduction by variable primary flow (VPF) chilled water systems for controlling the HVAC. The on-site experimental results indicate that average power consumptions are 44,935 kWh for the constant volume (CV) chilled water systems, and 39,025 kWh for the VPF system. Approximately 19% of the maximum energy-saving rate can be achieved if the HVAC system is operated as a VPF system. Additionally, the reduced quantity of accumulated CO2 emission varies from 0 to 44,186 kg with 0.623 kg-CO2 kwh-1 emission factor during the office hours of 08:00 (a.m.) to 20:00 (p.m.). The results demonstrate that switching the operation of an office building HVAC system from CV to VPF will significantly enhance energy savings and CO2 reduction. This study is will offer useful information for evaluating an indoor environmental policy with respect to energy savings and CO2 emission reduction for office HVACs used in subtropical regions.



Edited by:

Dongye Sun, Wen-Pei Sung and Ran Chen






W. P. Sung et al., "Improved Energy Performance of Air-Conditioning System Using Variable Primary Flow Chilled Water Systems in an Office Building", Applied Mechanics and Materials, Vols. 71-78, pp. 1973-1977, 2011

Online since:

July 2011




[1] S.C. Hu, Y.K. Chuah: Energy Vol. 28 (2003), P. 895.

[2] K. Ghali, N. Ghaddar and M. Ayoub: Int. J. Energy Res. Vol. 31 (2007), p.743.

[3] A. Gasparella and G.A. Longo: Int. J. Energy Res. Vol. 27 (2007), p.625.

[4] Q. Zhou, S. Wang and Z. Ma: Int. J. Energy Res. Vol. 33 (2009), p.903.

[5] K.T. Chan and F.W. Yu: Appl. Energy Vol. 72 (2002), p.565.

[6] F.W. Yu and K.T. Chan: Build. Environ. Vol. 42 (2007), p.3737.

[7] Z. Ma and S. Wang: Build. Environ. Vol. 44 (2009), p.1188.

[8] N. Nassif and S. Moujaes: Energy Build. Vol. 40 (2008), p.289.

[9] TPC. 2009 Electricity Emission Factor Report, Taiwan Power Company, information on http: /www. taipower. com. tw/TaipowerWeb/upload/files/1/d99051202. pdf.

[10] L.T. Wong and K.W. Mui: Appl. Energy Vol. 86 (2009), p. (1933).

[11] S. Pacala and S. Socolow: Science Vol. 305 (2004), p.968.

[12] J.A. Clarke, J. Cockroft, S. Conner, J.W. Hand, N.J. Kelly, R. Moore, T. O'Brien and P. Strachan: Energy Build. Vol. 34 (2002), p.933.

[13] F. Obayashi and Y. Tokunaga: A study of building energy management system based of multi agents, SICE Annual Conference in Fukui, Fukui University, Japan August 4-6, (2003).

[14] G.A. Atlanta: ASHRAE handbook-fundamentals (American Society of Heating, Refrigerating and Air-Conditioning Engineers Inc. 2001).

[15] Z. Lin and S. Deng: Build. Environ. Vol. 39 (2004), p.1101.

[16] C. Huang, Z. Zou, M. Li, X. Wang, W. Li, W. Huang, J. Yang and X. Xiao: Build. Environ. Vol. 42 (2007), p.1869.

[17] Trane Engineers Newsletter, Variable-Primary-Flow Systems Vol. 28 (1999).

[18] P. William, P.E. Bahnfleth and E. Peyer, ARTI-21CR/611-20070-01, Variable Primary Flow Chilled Water systems: Potential Benefits and Applications Issues, Final Report Volume 1, March (2004).

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