The performance of a ventilation system affects air quality, thermal comfort, and energy consumption in indoor environments. To evaluate the performance of displacement ventilation under various room configurations, steady Reynolds Averaged Navier–Stokes (RANS) Computational Fluid Dynamics (CFD) simulations were used. The CFD model was validated using measurements of a full-scale test room. The age of air concept was used to evaluate the ventilation performance regarding indoor air quality. The PD index was used to control the case studies for draft risk. Twelve cases with different configurations were systematically studied and compared with the reference case. The configurations included plan aspect ratio, exhaust opening position, inlet position and geometry, and internal heat gains. The results showed that the overall ventilation performance of a room is less sensitive to room configurations compared with local ventilation performance around the occupants. However, almost in all cases, the occupants were exposed to better-than-average air quality in most cases. The results also indicated that when internal heat gains are small, displacement ventilation should be used with caution.
Practical application: Any HVAC system design is based on assumptions made for ventilation performance. Comprehensive knowledge of the influential factors is critical for an efficient design. Regarding the architecture and interior design, the architects are also involved in the ventilation systems since they have an axial role in decision making for room configuration, including but not limited to room geometry, the position of inlet and outlet air terminals, and heat/pollutant sources. Consequently, the impact of room configuration on ventilation performance is of practical importance in the architecture, engineering, and construction industry.
ZhangSMumovicDStampS, et al.What do we know about indoor air quality of nurseries? A review of the literature. Building Serv Eng Res Technol2021; 42: 603–632.
2.
AganovicASteffensenMCaoG. CFD study of the air distribution and occupant draught sensation in a patient ward equipped with protected zone ventilation. Building Environ2019; 162: 106279.
3.
ArjmandiHAminiRkhaniF, et al.Minimizing the respiratory pathogen transmission: numerical study and multi-objective optimization of ventilation systems in a classroom. Therm Sci Eng Prog2021: 101052.
4.
RisbeckMJBazantMZJiangZ, et al.Quantifying the tradeoff between energy consumption and the risk of airborne disease transmission for building HVAC systems. Sci Technol Built Environ2022; 28: 240–254.
5.
RothamerDASandersSReindlD, et al.Strategies to minimize SARS-CoV-2 transmission in classroom settings: combined impacts of ventilation and mask effective filtration efficiency. Sci Technol Built Environ2021; 27: 1181–1203.
6.
YangBMelikovAKKabanshiA, et al.A review of advanced air distribution methods - theory, practice, limitations and solutions. Energy and Buildings2019; 202: 109359.
7.
CaoGAwbiHYaoR, et al.A review of the performance of different ventilation and airflow distribution systems in buildings. Building Environ2014; 73: 171–186.
8.
ASHRAE. 2013 ASHRAE Handbook: Fundamentals. American Society of heating, refrigerating and air-conditioning engineers, 2013.
9.
ChenQ. Ventilation performance prediction for buildings: A method overview and recent applications. Building Environ2009; 44: 848–858.
10.
TahmasebiFWangYCooperE, et al.Window operation behaviour and indoor air quality during lockdown: A monitoring-based simulation-assisted study in London. Building Serv Eng Res Technol2022; 43: 5–21.
11.
DengH-YFengZCaoS-J. Influence of air change rates on indoor CO 2 stratification in terms of Richardson number and vorticity. Building Environ2018; 129: 74–84.
12.
HuXGaoYHanY, et al.Study on the airflow and vortex distributions in a long-narrow enclosed space. Sci Technol Built Environ2022; 0: 1–14.
13.
HensenJLMHamelinckMJH. Energy simulation of displacement ventilation in offices. Building Serv Eng Res Technol1995; 16: 77–81.
14.
GilaniSMontazeriHBlockenB. CFD simulation of stratified indoor environment in displacement ventilation: Validation and sensitivity analysis. Building Environ2016; 95: 299–313.
15.
AghamolaeiRFallahpourMMirzaeiPA. Tempo-spatial thermal comfort analysis of urban heat island with coupling of CFD and building energy simulation. Energy and Buildings2021; 251: 111317.
16.
BlockenB. Computational Fluid Dynamics for urban physics: Importance, scales, possibilities, limitations and ten tips and tricks towards accurate and reliable simulations. Building Environ2015; 91: 219–245.
17.
MontazeriHBlockenBHensenJLM. Evaporative cooling by water spray systems: CFD simulation, experimental validation and sensitivity analysis. Building Environ2015; 83: 129–141.
18.
Hormigos-JimenezSPadilla-MarcosMAMeissA, et al.Experimental validation of the age-of-the-air CFD analysis: A case study. Sci Technol Built Environ2018; 24: 994–1003.
19.
ChanteloupVMiradeP-S. Computational fluid dynamics (CFD) modelling of local mean age of air distribution in forced-ventilation food plants. J Food Eng2009; 90: 90–103.
20.
Porras-AmoresCViñas-ArrebolaCRodríguez-SánchezA, et al.Assessing the potential use of strategies independent from the architectural design to achieve efficient ventilation: A Spanish case study. Building Serv Eng Res Technol2014; 35: 529–542.
21.
ChenZXinJLiuP. Air quality and thermal comfort analysis of kitchen environment with CFD simulation and experimental calibration. Building Environ2020; 172: 106691.
22.
Rabanillo-HerreroMÁngel Padilla-MarcosMFeijó-MuñozJ, et al.Ventilation efficiency assessment according to the variation of opening position in L-shaped rooms. Build Simul, Epub ahead of print 14 August 2019. DOI: 10.1007/s12273-019-0566-9.
23.
SandbergM. What is ventilation efficiency?Building Environ1981; 16: 123–135.
24.
AbantoJBarreroDReggioM, et al.Airflow modelling in a computer room. Building Environ2004; 39: 1393–1402.
25.
ShermanMHWalkerIS. Measured Air Distribution Effectiveness for Residential Mechanical Ventilation. HVAC&R Res2009; 15: 211–229.
26.
LinZChowTTTsangCF, et al.CFD study on effect of the air supply location on the performance of the displacement ventilation system. Building Environ2005; 40: 1051–1067.
27.
NingMMengjieSMingyinC, et al.Computational fluid dynamics (CFD) modelling of air flow field, mean age of air and CO2 distributions inside a bedroom with different heights of conditioned air supply outlet. Appl Energy2016; 164: 906–915.
28.
TripathiBMoulicSGAroraLRC. A CFD analysis of room aspect ratio on the effect of buoyancy and room air flow. Therm Sci2007; 11: 16.
29.
DasPChalabiZJonesB, et al.Multi-objective methods for determining optimal ventilation rates in dwellings. Building Environ2013; 66: 72–81.
30.
Hormigos-JimenezSPadilla-MarcosMÁMeissA, et al.Computational fluid dynamics evaluation of the furniture arrangement for ventilation efficiency. Building Serv Eng Res Technol2018; 39: 557–571.
31.
ChenQGlicksmanLRYuanX, et al.Performance Evaluation and Development of Design Guidelines for Displacement Ventilation: Final Report to ASHRAE TC 5.3 - Room Air Distribution ; TC 4.10 - Indoor Environment Modeling on ASHRAE Research Project - RP-949. ASHRAE, 1999, https://books.google.com/books?id=vU8ftwAACAAJ.
32.
BrundageDMStoppelmoorWHBaertE, et al.ASHRAE Standard 129-Standard Method of Measuring Air Change Effectiveness.
33.
ASHRAE-ANSI. ASHRAE 62.1-2016 Ventilation for Acceptable Indoor Air Quality. Atlanta, GA, 2016.
34.
RimDNovoselacA. Ventilation effectiveness as an indicator of occupant exposure to particles from indoor sources. Building Environ2010; 45: 1214–1224.
35.
MelikovAKNielsenJB. Local thermal discomfort due to draft and vertical temperature difference in rooms with displacement ventilation. ASHRAE Trans1989; 95: 1050–1057.
36.
Fluent 2020-R2 user’s guide. ANSYS Inc.
37.
ZhangT (Tim)LeeKChenQ, et al. A simplified approach to describe complex diffusers in displacement ventilation for CFD simulations. Indoor Air2009; 19: 255–267.
38.
ChenQSrebricJ. A Procedure for Verification, Validation, and Reporting of Indoor Environment CFD Analyses. HVAC&R Res2002; 8: 201–216.
39.
YakhotVOrszagSA. Renormalization group analysis of turbulence. I. Basic theory. J Scientific Computing1986; 1: 3–51.
40.
ZhangZZhangWZhaiZJ, et al.Evaluation of Various Turbulence Models in Predicting Airflow and Turbulence in Enclosed Environments by CFD: Part 2—Comparison with Experimental Data from Literature. HVAC&R Res2007; 13: 871–886.
41.
CookMJLomasKJ. Buoyancy-driven displacement ventilation flows: Evaluation of two eddy viscosity turbulence models for prediction. Building Serv Eng Res Technol1998; 19: 15–21.
42.
JiYCookMJ. Numerical studies of displacement natural ventilation in multi-storey buildings connected to an atrium. Building Serv Eng Res Technol2007; 28: 207–222.
43.
ZhangWMakCWongH. Pollutant dispersion in a natural ventilated dental clinic. Building Serv Eng Res Technol2013; 34: 245–258.
44.
ZhangSLinZAiZ, et al.Effects of operation parameters on performances of stratum ventilation for heating mode. Building Environ2019; 148: 55–66.
45.
Fluent Customization Manual. ANSYS Inc.
46.
FangerPOMelikovAKHanzawaH, et al.Turbulence and draft. The turbulence of airflow has a significant impact on the sensation of draft. ASHRAE Journal1989; 31: 18–25.
47.
ISO I. 7730. Ergonomics of the thermal environment Analytical determination and interpretation of thermal comfort using calculation of the PMV and PPD indices and local thermal comfort criteria. Management2005; 3: e615.
48.
ZhaiZJZhangZZhangW, et al.Evaluation of Various Turbulence Models in Predicting Airflow and Turbulence in Enclosed Environments by CFD: Part 1—Summary of Prevalent Turbulence Models. HVAC&R Res2007; 13: 853–870.
