Thermal Comfort and Energy Saving Evaluation of a Combined System in an Office Room Using Displacement Ventilation
In this paper, the energy saving and human thermal
comfort in a typical office room are investigated. The impact of a
combined system of exhaust inlet air with light slots located at the
ceiling level in a room served by displacement ventilation system is
numerically modelled. Previous experimental data are used to
validate the Computational Fluid Dynamic (CFD) model. A case
study of simulated office room includes two seating occupants, two
computers, two data loggers and four lamps. The combined system is
located at the ceiling level above the heat sources. A new method of
calculation for the cooling coil load in Stratified Air Distribution
(STRAD) system is used in this study. The results show that 47.4%
energy saving of space cooling load can be achieved by combing the
exhaust inlet air with light slots at the ceiling level above the heat
sources.
[1] S. Riffat, X. Zhao, P. Doherty, Review of research into and application
of chilled ceilings and displacement ventilation systems in Europe,
International Journal of Energy Research, 28 (2004) 257-286.
[2] H. Skistad, Displacement ventilation, Research Studies Press, 1994.
[3] K. J. Loudermilk, Underfloor air distribution solutions for open office
applications, Transactions-American Society of Heating Refrigerating
and Air Conditioning Engineers, 105 (1999) 605-613.
[4] H.-J. Park, D. Holland, The effect of location of a convective heat source
on displacement ventilation: CFD study, Building and environment, 36
(2001) 883-889.
[5] L. Tian, Z. Lin, Q. Wang, Comparison of gaseous contaminant diffusion
under stratum ventilation and under displacement ventilation, Building
and Environment, 45 (2010) 2035-2046.
[6] [6] J.B. Olivieri, T. Singh, effect of supply and return air outlets on
stratification / energy consumption ASHRAE Transaction 1, 188 (1982).
[7] R. L. Gorton, H. M. Bagheri, "Determination of Performance
Characteristics of a System Designed for Stratified Cooling in Operation
during the Heating Season, (1986).
[8] J. C. Lam, A. L. Chan, CFD analysis and energy simulation of a
gymnasium, Building and Environment, 36 (2001) 351-358.
[9] A. Awad, R. Calay, O. Badran, A. Holdo, An experimental study of
stratified flow in enclosures, Applied Thermal Engineering, 28 (2008)
2150-2158.
[10] M. Filler, Best practices for underfloor air systems, ASHRAE journal,
46 (2004) 39-46.
[11] G. Hunt, P. Linden, The fluid mechanics of natural ventilation—
displacement ventilation by buoyancy-driven flows assisted by wind,
Building and Environment, 34 (1999) 707-720.
[12] R. Calay, B. Borresen, A. Holdø, Selective ventilation in large
enclosures, Energy and buildings, 32 (2000) 281-289.
[13] J. Zheng, Q. Chen, K. Lee, Establishment of design procedures to
predict room airflow requirements in partially mixed room air
distribution systems, ASHRAE Research Project (RP-1522) Final
Report, (2012).
[14] S. Holmberg, Q. Chen, Air flow and particle control with different
ventilation systems in a classroom, Indoor air, 13 (2003) 200-204.
[15] X. Hongtao, G. Naiping, N. Jianlei, A method to generate effective
cooling load factors for stratified air distribution systems using a floorlevel
air supply, HVAC&R Research, 15 (2009) 915-930.
[16] Y. Cheng, J. Niu, N. Gao, Stratified air distribution systems in a large
lecture theatre: A numerical method to optimize thermal comfort and
maximize energy saving, Energy and Buildings, 55 (2012) 515-525.
[17] FLUENT, A. Theory Guide, 2011.
[18] A. Makhoul, K. Ghali, N. Ghaddar, Desk fans for the control of the
convection flow around occupants using ceiling mounted personalized
ventilation, Building and Environment, 59 (2013) 336-348.
[1] S. Riffat, X. Zhao, P. Doherty, Review of research into and application
of chilled ceilings and displacement ventilation systems in Europe,
International Journal of Energy Research, 28 (2004) 257-286.
[2] H. Skistad, Displacement ventilation, Research Studies Press, 1994.
[3] K. J. Loudermilk, Underfloor air distribution solutions for open office
applications, Transactions-American Society of Heating Refrigerating
and Air Conditioning Engineers, 105 (1999) 605-613.
[4] H.-J. Park, D. Holland, The effect of location of a convective heat source
on displacement ventilation: CFD study, Building and environment, 36
(2001) 883-889.
[5] L. Tian, Z. Lin, Q. Wang, Comparison of gaseous contaminant diffusion
under stratum ventilation and under displacement ventilation, Building
and Environment, 45 (2010) 2035-2046.
[6] [6] J.B. Olivieri, T. Singh, effect of supply and return air outlets on
stratification / energy consumption ASHRAE Transaction 1, 188 (1982).
[7] R. L. Gorton, H. M. Bagheri, "Determination of Performance
Characteristics of a System Designed for Stratified Cooling in Operation
during the Heating Season, (1986).
[8] J. C. Lam, A. L. Chan, CFD analysis and energy simulation of a
gymnasium, Building and Environment, 36 (2001) 351-358.
[9] A. Awad, R. Calay, O. Badran, A. Holdo, An experimental study of
stratified flow in enclosures, Applied Thermal Engineering, 28 (2008)
2150-2158.
[10] M. Filler, Best practices for underfloor air systems, ASHRAE journal,
46 (2004) 39-46.
[11] G. Hunt, P. Linden, The fluid mechanics of natural ventilation—
displacement ventilation by buoyancy-driven flows assisted by wind,
Building and Environment, 34 (1999) 707-720.
[12] R. Calay, B. Borresen, A. Holdø, Selective ventilation in large
enclosures, Energy and buildings, 32 (2000) 281-289.
[13] J. Zheng, Q. Chen, K. Lee, Establishment of design procedures to
predict room airflow requirements in partially mixed room air
distribution systems, ASHRAE Research Project (RP-1522) Final
Report, (2012).
[14] S. Holmberg, Q. Chen, Air flow and particle control with different
ventilation systems in a classroom, Indoor air, 13 (2003) 200-204.
[15] X. Hongtao, G. Naiping, N. Jianlei, A method to generate effective
cooling load factors for stratified air distribution systems using a floorlevel
air supply, HVAC&R Research, 15 (2009) 915-930.
[16] Y. Cheng, J. Niu, N. Gao, Stratified air distribution systems in a large
lecture theatre: A numerical method to optimize thermal comfort and
maximize energy saving, Energy and Buildings, 55 (2012) 515-525.
[17] FLUENT, A. Theory Guide, 2011.
[18] A. Makhoul, K. Ghali, N. Ghaddar, Desk fans for the control of the
convection flow around occupants using ceiling mounted personalized
ventilation, Building and Environment, 59 (2013) 336-348.
@article{"International Journal of Mechanical, Industrial and Aerospace Sciences:70424", author = "A. Q. Ahmed and S. Gao", title = "Thermal Comfort and Energy Saving Evaluation of a Combined System in an Office Room Using Displacement Ventilation", abstract = "In this paper, the energy saving and human thermal
comfort in a typical office room are investigated. The impact of a
combined system of exhaust inlet air with light slots located at the
ceiling level in a room served by displacement ventilation system is
numerically modelled. Previous experimental data are used to
validate the Computational Fluid Dynamic (CFD) model. A case
study of simulated office room includes two seating occupants, two
computers, two data loggers and four lamps. The combined system is
located at the ceiling level above the heat sources. A new method of
calculation for the cooling coil load in Stratified Air Distribution
(STRAD) system is used in this study. The results show that 47.4%
energy saving of space cooling load can be achieved by combing the
exhaust inlet air with light slots at the ceiling level above the heat
sources.", keywords = "Air conditioning, Displacement ventilation, Energy
saving, Thermal comfort.", volume = "9", number = "6", pages = "1101-6", }