Numerical Investigation of Displacement Ventilation Effectiveness
Displacement ventilation of a room with an occupant is modeled using CFD. The geometry of manikin is accurately represented in CFD model to minimize potential. Indoor zero equation turbulence model is used to simulate all cases and the effect of the thermal radiation from manikin is taken into account. After validation of the code, predicted mean vote, mean age of air, and ventilation effectiveness are used to predict the thermal comfort zones and indoor air quality. The effect of the inlet velocity and temperature on the thermal comfort and indoor air quality is investigated. The results show that the inlet velocity has great effect on the thermal comfort and indoor air quality and low inlet velocity is sufficient to establish comfortable conditions inside the room. In addition, the displacement ventilation system achieves not only thermal comfort in ventilated rooms, but also energy saving of fan power.
[1] ISO, BS EN ISO Standard 7730. Moderate thermal environments determination of the PMV and PPD indices and specification of the conditions for thermal comfort, International Standards Organization (1995).
[2] S. Murakami, S. Kato and J. Zeng, Flow and temperature fields around a human body with various room air distributions: CFD study on computational thermal manikin—part I, ASHRAE Transactions 103 (1997) 3-15.
[3] H. O. Nilsson, I. Holmer, Comfort climate evaluation with thermal manikin methods and computer simulation models, Indoor Air 13 (2003) 28-37.
[4] V. Yakhot, S. A. Orszag, Renormalization group analysis of turbulence. I. Basic theory, Journal of Scientific Computing 1 (1986) 3-51.
[5] S. Murakami, S. Kato, J. Zeng, Combined simulation of airflow, radiation and moisture transport for heat release from a human body, Building and Environment 35 (2000) 489-500.
[6] B. Gebhart, A new method for calculating radiative exchanges, ASHRAE Transactions 65 (1959) 321-323.
[7] S. Murakami, Analysis and design of the micro-climate around the human body with respiration by CFD, Indoor Air 14 (2004) 144-156.
[8] A. Novoselac, B.J. Burley and J. Srebric, Development of new and validation of existing convection correlations for rooms with displacement ventilation systems, Energy Build 2006; 38(3):163-73.
[9] J.W. Jeong, S. A. Mumma, Ceiling radiant cooling panel capacity enhanced by mixed convection in mechanically ventilated spaces, Appl Thermal Eng 2003; 23(18) 2293-306.
[10] R. Karadag, The investigation of relation between radiative and convective heat transfer coefficients at the ceiling in a cooled ceiling room, Energy Conversion Manag 2009; 50(1) 1-5.
[11] F. Causone, S.P. Corgnati, M. Filippi, B. W. Olesen, Experimental evaluation of heat transfer coefficients between radiant ceiling and room, Energy Build 2009; 41(6) 622-8.
[12] L. P. Thomas, B.M. Marino, R. Tovar, J. Castillo, Flow generated by a thermal plume in a cooled-ceiling system, Energy Build 43(10) (2011) 2727-36.
[13] C. N. Sideroff, T. Q. Dang, Challenges in evaluating turbulence models with benchmark cases, in: ASHRAE Summer Meeting, Denver, Colorado, 2005.
[14] P.A. Durbin, Near-wall turbulent closure modelling without ‘damping functions’, Theoretical and Computational Fluid Dynamics 3 (1991) 1-13.
[15] J. Srebric, V. Vukovic, Simplified physical and simulation modeling of building occupants a seminar, in: Experimental and CFD Benchmark Studies of Indoor Flow around Thermal Manikins”. ASHRAE winter meeting, Chicago, 2006.
[16] ASHRAE Handbook: Applications, American Society of Heating, Refrigerating and Air-Conditioning Engineers, Inc., Atlanta, GA, 2003.
[17] ISO.ISO7730: moderate thermal environments determination of the PMV and PPD indices and specification of the conditions for thermal comfort. Geneva: International Organization for Standardization, 1994.
[18] Fluent Inc. 2001 Getting Started with Airpak 2.
[19] Q. Chen, W. Xu, A zero-equation turbulence model for indoor airflow simulation, Energy and Buildings 28 (1998) 137-144.
[20] D. Etheridge, M. Sandberg, Building ventilation, theory and measurement, England: John Wiley and Sons Ltd., 1996.
[21] P. O. Fanger, Thermal Comfort- Analysis and Applications in Environmental Engineering, Robert E. Krieger, Florida, 1982.
[22] Moderate thermal environments -- determination of PMV and PPD indices and specification of the conditions for thermal comfort, ISO 7730, International Standards Organization, Geneva, Switzerland, 1984.
[23] M. Sandberg, M. Sjöberg, The use of moments for assessing air quality in ventilated rooms. Building and Environment 18 (1983) 181-197.
[24] M. A. Aziz, Ibrahim A.M. Gad, E.F.A. Mohammed, R. H. Mohammed, Experimental and numerical study of influence of air ceiling diffusers on room airflow characteristics, Energy and Buildings 55 (2012) 738-746.
[25] J. D. Spitler, An experimental investigation of air flow and convective heat transfer in enclosures having large ventilative flow rates, Ph.D. Thesis, University of Illinois at Urbana-Champaign, 1990.
[26] A. J. Baker, P. T. Williams, and R. M. Kelso, Numerical Calculation of Room Air Motion - part 1: Math, Physics and CFD Modeling, ASHRAE Transactions 100 Part1 514-530.
[27] A. F. Alfahaid, Effects of ventilation on human Thermal comfort in rooms, Ph.D. Thesis, Old Dominion University, December 2000.
[1] ISO, BS EN ISO Standard 7730. Moderate thermal environments determination of the PMV and PPD indices and specification of the conditions for thermal comfort, International Standards Organization (1995).
[2] S. Murakami, S. Kato and J. Zeng, Flow and temperature fields around a human body with various room air distributions: CFD study on computational thermal manikin—part I, ASHRAE Transactions 103 (1997) 3-15.
[3] H. O. Nilsson, I. Holmer, Comfort climate evaluation with thermal manikin methods and computer simulation models, Indoor Air 13 (2003) 28-37.
[4] V. Yakhot, S. A. Orszag, Renormalization group analysis of turbulence. I. Basic theory, Journal of Scientific Computing 1 (1986) 3-51.
[5] S. Murakami, S. Kato, J. Zeng, Combined simulation of airflow, radiation and moisture transport for heat release from a human body, Building and Environment 35 (2000) 489-500.
[6] B. Gebhart, A new method for calculating radiative exchanges, ASHRAE Transactions 65 (1959) 321-323.
[7] S. Murakami, Analysis and design of the micro-climate around the human body with respiration by CFD, Indoor Air 14 (2004) 144-156.
[8] A. Novoselac, B.J. Burley and J. Srebric, Development of new and validation of existing convection correlations for rooms with displacement ventilation systems, Energy Build 2006; 38(3):163-73.
[9] J.W. Jeong, S. A. Mumma, Ceiling radiant cooling panel capacity enhanced by mixed convection in mechanically ventilated spaces, Appl Thermal Eng 2003; 23(18) 2293-306.
[10] R. Karadag, The investigation of relation between radiative and convective heat transfer coefficients at the ceiling in a cooled ceiling room, Energy Conversion Manag 2009; 50(1) 1-5.
[11] F. Causone, S.P. Corgnati, M. Filippi, B. W. Olesen, Experimental evaluation of heat transfer coefficients between radiant ceiling and room, Energy Build 2009; 41(6) 622-8.
[12] L. P. Thomas, B.M. Marino, R. Tovar, J. Castillo, Flow generated by a thermal plume in a cooled-ceiling system, Energy Build 43(10) (2011) 2727-36.
[13] C. N. Sideroff, T. Q. Dang, Challenges in evaluating turbulence models with benchmark cases, in: ASHRAE Summer Meeting, Denver, Colorado, 2005.
[14] P.A. Durbin, Near-wall turbulent closure modelling without ‘damping functions’, Theoretical and Computational Fluid Dynamics 3 (1991) 1-13.
[15] J. Srebric, V. Vukovic, Simplified physical and simulation modeling of building occupants a seminar, in: Experimental and CFD Benchmark Studies of Indoor Flow around Thermal Manikins”. ASHRAE winter meeting, Chicago, 2006.
[16] ASHRAE Handbook: Applications, American Society of Heating, Refrigerating and Air-Conditioning Engineers, Inc., Atlanta, GA, 2003.
[17] ISO.ISO7730: moderate thermal environments determination of the PMV and PPD indices and specification of the conditions for thermal comfort. Geneva: International Organization for Standardization, 1994.
[18] Fluent Inc. 2001 Getting Started with Airpak 2.
[19] Q. Chen, W. Xu, A zero-equation turbulence model for indoor airflow simulation, Energy and Buildings 28 (1998) 137-144.
[20] D. Etheridge, M. Sandberg, Building ventilation, theory and measurement, England: John Wiley and Sons Ltd., 1996.
[21] P. O. Fanger, Thermal Comfort- Analysis and Applications in Environmental Engineering, Robert E. Krieger, Florida, 1982.
[22] Moderate thermal environments -- determination of PMV and PPD indices and specification of the conditions for thermal comfort, ISO 7730, International Standards Organization, Geneva, Switzerland, 1984.
[23] M. Sandberg, M. Sjöberg, The use of moments for assessing air quality in ventilated rooms. Building and Environment 18 (1983) 181-197.
[24] M. A. Aziz, Ibrahim A.M. Gad, E.F.A. Mohammed, R. H. Mohammed, Experimental and numerical study of influence of air ceiling diffusers on room airflow characteristics, Energy and Buildings 55 (2012) 738-746.
[25] J. D. Spitler, An experimental investigation of air flow and convective heat transfer in enclosures having large ventilative flow rates, Ph.D. Thesis, University of Illinois at Urbana-Champaign, 1990.
[26] A. J. Baker, P. T. Williams, and R. M. Kelso, Numerical Calculation of Room Air Motion - part 1: Math, Physics and CFD Modeling, ASHRAE Transactions 100 Part1 514-530.
[27] A. F. Alfahaid, Effects of ventilation on human Thermal comfort in rooms, Ph.D. Thesis, Old Dominion University, December 2000.
@article{"International Journal of Mechanical, Industrial and Aerospace Sciences:66379", author = "Ramy H. Mohammed", title = "Numerical Investigation of Displacement Ventilation Effectiveness", abstract = "Displacement ventilation of a room with an occupant is modeled using CFD. The geometry of manikin is accurately represented in CFD model to minimize potential. Indoor zero equation turbulence model is used to simulate all cases and the effect of the thermal radiation from manikin is taken into account. After validation of the code, predicted mean vote, mean age of air, and ventilation effectiveness are used to predict the thermal comfort zones and indoor air quality. The effect of the inlet velocity and temperature on the thermal comfort and indoor air quality is investigated. The results show that the inlet velocity has great effect on the thermal comfort and indoor air quality and low inlet velocity is sufficient to establish comfortable conditions inside the room. In addition, the displacement ventilation system achieves not only thermal comfort in ventilated rooms, but also energy saving of fan power.
", keywords = "Displacement ventilation, Energy saving, Thermal comfort, Turbulence model.", volume = "8", number = "2", pages = "250-6", }
