A tale of two populations: thermal comfort in air-conditioned and naturally ventilated offices in Thailand

Busch, John

doi:10.1016/0378-7788(92)90016-a

Cited by 207 publications

(96 citation statements)

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“…In naturally ventilated buildings, occupants may accept higher temperatures than in air-conditioned buildings, and natural wind with a relatively high average velocity is more acceptable than mechanical wind (Busch, 1992;Ealiwa et al, 2001;de Dear and Brager, 2002). The occupants of naturally ventilated buildings accept a significantly wider range of temperatures (Busch, 1992;Ealiwa et al, 2001;de Dear and Brager (2002)) that fall out of the standard based on Fanger's thermal comfort model (ISO 7730, 2005).…”

Section: Introductionmentioning

confidence: 99%

“…The occupants of naturally ventilated buildings accept a significantly wider range of temperatures (Busch, 1992;Ealiwa et al, 2001;de Dear and Brager (2002)) that fall out of the standard based on Fanger's thermal comfort model (ISO 7730, 2005). Busch (1992) carried out a field study of thermal comfort in Bangkok, where more than 1,100 office workers responded to a questionnaire while simultaneous physical measurements were taken. In that study, both air-conditioned and naturally ventilated offices were surveyed.…”

Section: Introductionmentioning

confidence: 99%

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Correlations in thermal comfort and natural wind

Kang

Song

Schiavon

2013

Journal of Thermal Biology

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a b s t r a c tMany field surveys have shown that naturally ventilated buildings are favorable to human thermal comfort and may allow higher cooling temperatures than air-conditioned buildings. Recreating natural wind characteristics with a mechanical cooling system may diminish the drawbacks of conventional cooling systems such as drafts and high energy demands.Natural wind characteristics (wind velocity, direction, turbulent intensity, temperature and relative humidity) were recorded in a mountain environment and correlated with the human thermal sensation of 48 subjects. Natural wind fluctuation characteristics were analyzed using the Fast Fourier Transform (FFT) analysis. The dynamic characteristics of natural wind were averaged through the power spectrum exponent (β−value), which represents the energy distribution of the turbulent flow of natural wind. The power spectrum exponent (β−value) of the natural wind will decrease when the mean velocity increases, while it will increase when the turbulent intensity increases. The power spectrum exponent (β−value) was correlated (Spearman's rank coefficient¼ 0.56, po0.001) with thermal comfort. The power spectrum exponent (β-value) for people feeling comfortable has a median value of 1.62 [1.41-1.80 for the first and third quartiles, respectively] and the β−value for people feeling uncomfortable has a median value of 1.10 [0.97-1.25].

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Correlations in thermal comfort and natural wind

Kang

Song

Schiavon

2013

Journal of Thermal Biology

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“…To reduce energy used by mechanical cooling systems, people utilize natural ventilation to cool buildings by opening windows if outdoor climate conditions are appropriate. Natural ventilation not only helps to reduce energy consumed by air-conditioning systems in buildings, but also can improve indoor air quality [1], and provide a high level of thermal comfort [2]. The benefits of natural ventilation are becoming increasingly recognized and sought after.…”

Section: Introductionmentioning

confidence: 99%

Study of natural ventilation in buildings by large eddy simulation

Jiang

Chen

2001

Journal of Wind Engineering and Industrial Aerodynamics

144

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Natural ventilation in buildings can create a comfortable and healthy indoor environment, and can save energy used in the mechanical ventilation systems. Two subgrid-scale models of large eddy simulation (LES), a Smagorinsky subgrid-scale (SS) model and a Filtered dynamic subgrid-scale (FDS) model, have been used to study airflow in buildings with natural ventilation. It was found that, for fully developed turbulence flow with a high Reynolds number, both the SS and FDS models provide good results. However, if the flow has both turbulent and laminar characteristics, or the wall effect is significant, the SS model performs poorly due to its constant model coefficient. The FDS model can still predict this flow correctly because its model coefficient varies over space and time according to flow types. Furthermore, for a single-sided ventilation, it is important to obtain instantaneous flow information in order to correctly predict ventilation rate and air change effectiveness. Reynolds Averaged Navier Stokes (RANS) modeling cannot correctly calculate the ventilation rate in this case.

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“…By delivering a sufficient amount of outdoor cool fresh air into the room, excess heat and internally generated contaminant concentration levels can be removed and reduced. Natural ventilation appeared as an attractive strategy used in the past to provide an acceptable microclimate in the space being ventilated (Busch, 1992), but it is limited to range of climates, microclimates, building types, etc. (Allocca et al, 2003).…”

Section: Introductionmentioning

confidence: 99%

Experimental and numerical investigations of a ventilation strategy – impinging jet ventilation for an office environment

Chen¹

2014

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A well-functioning, energy-efficient ventilation system is of vital importance to offices, not only to provide the kind of comfortable, healthy indoor environment necessary for the well-being and productive work performance of occupants, but also to reduce energy use in buildings and the associated impact of CO 2 emissions on the environment. To achieve these goals impinging jet ventilation has been developed as an innovative ventilation concept.In an impinging jet ventilation system, a high momentum of air jet is discharged downwards, strikes the floor and spreads over it, thus distributing the fresh air along the floor in the form of a very thin shear layer. This system retains advantages of mixing and stratification from conventional air distribution methods, while capable of overcoming their shortcomings.The aim of this thesis is to reach a thorough understanding of impinging jet ventilation for providing a good thermal environment for an office, by using Computational Fluid Dynamics (CFD) supported by detailed measurements. The full-field measurements were carried out in two test rooms located in a large enclosure giving relatively stable climate conditions. This study has been divided into three parts where the first focuses on validation of numerical investigations against measurements, the second addresses impacts of a number of design parameters on the impinging jet flow field and thermal comfort level, and the third compares ventilation performance of the impinging jet supply device with other air supply devices intended for mixing, wall confluent jets and displacement ventilation, under specific room conditions. In the first part, velocity and temperature distributions of the impinging jet flow field predicted by different turbulence models are compared with detailed measurements. Results from the non-isothermal validation studies show that the accuracy of the simulation results is to a great extent dependent on the complexity of the turbulence models, due to complicated flow phenomena related to jet impingement, such as recirculation, curvature and instability. The f v  2 turbulence model shows the best performance with measurements, which is slightly better than the SST k-ω model but much better than the RNG k-ε model. The difference is assumed to be essentially related to the magnitude of turbulent kinetic energy predicted in the vicinity of the stagnation region. Results from the isothermal study show that both the SST k-ω and RNG k-ε models predict similar wall jet behaviours of the impinging jet flow. IVIn the second part, three sets of parametric studies were carried out by using validated CFD models. The first parametric study shows that the geometry of the air supply system has the most significant impact on the flow field. The rectangular air supply device, especially the one with larger aspect ratio, provides a longer penetration distance to the room, which is suitable for industrial ventilation. The second study reveals that the interaction effect of cooling ceiling, heat sources ...

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A tale of two populations: thermal comfort in air-conditioned and naturally ventilated offices in Thailand

Cited by 207 publications

References 5 publications

Correlations in thermal comfort and natural wind

Correlations in thermal comfort and natural wind

Study of natural ventilation in buildings by large eddy simulation

Experimental and numerical investigations of a ventilation strategy – impinging jet ventilation for an office environment

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