The Influence of Ventilation Design Mixes on the Thermal Environment in Elementary School Classrooms

Abstract

The roofs of most of the buildings in Taiwan are exposed to direct (overhead) solar radiation during the summer season because it is located near the Tropic of Cancer. The estimated yearly solar heat gain received from a roof is 2.78 times greater than that gained from a south-side wall (the second highest in terms of solar heat gain). Since most elementary schools in Taiwan are not equipped with air conditioners, the classrooms, especially those located on the upper floors, are regularly overheated. Solving the problem of ventilation and improving the thermal environment in Taiwan elementary school classrooms is an important endeavor. CFD simulations were conducted to investigate six combinations of designs that can incorporate natural ventilation (double roofs, ‘‘Covered Ridge with Sidewall Opening’’ (CRSOs), roof ridge openings, and window layout) influence indoor thermal environments, especially during the summer season when the outdoor wind velocity is low. The results show that when a double roof, roof ridge openings, and a CRSO are implemented, both the ventilation performance and the thermal environment of the classrooms are improved, regardless of whether the windows are laid out in a staggered formation (high-low) or in a conventional window layout.

Keywords

classroom natural ventilation CFD (computational fluid dynamics)CRSO (covered ridge with sidewall opening)double roof

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References

Koo LCL , Luk MY , Mok MY , Yuen JHF , Yuen TYS : Health effects from air conditioning: epidemiologic studies on schools and offices in Hong Kong: in Proc Indoor and Built Environment Problems in Asia , Kuala Lumpur, Malaysia, 1997 .

Synnefa A. , Polichronaki E. , Papagiannopoulou E. , Santamouris M. , Mihalakakou G. , Doukas P. , Siskos PA , Bakeas E. , Dremetsika A. , Geranios A. , Delakou A. : An experimental investigation of the indoor air quality in fifteen school buildings in Athens, Greece: Int J Ventilation 2003;2(3):185-201.

Conceição EZE , Lúcio Mmjr : Air quality inside a school building: air exchange monitoring, evolution of carbon dioxide and assessment of ventilation strategies: Int J Ventilation 2006;5(6):259-270.

Karimipanah T. , Awbi HB , Sandberg M. , Blomqvist C. : Investigation of air quality, comfort parameters and effectiveness for two floor-level air supply systems in classrooms: Building Environ 2007;42(2):647-655.

Khedari J. , Boonsri B. , Hirunlabh J. : Ventilation impact of a solar chimney on indoor temperature fluctuation and air change in a school building: Energy Buildings 2000;32:89-93.

Lomas KJ : Architectural design of an advanced naturally ventilated building form: Energy Buildings 2007;39:166-181.

Chang PC , Chiang CM , Lai CM : Development and preliminary evaluation of double roof prototypes incorporating RBS (Radiant Barrier System): Energy Buildings 2008;40(2):140-147.

Lai CM , Huang JY , Chiou JS : Optimal spacing for double-skin roofs: Building Environ 2008 ;43(10):1749-1754.

Cmhc : Construction of Wood House in Canada . Canada, 2001.

10.

Çengel YA : Heat Transfer: A Practical Approach, 2nd edn. New York, McGraw-Hill Companies, Inc., 2003.

11.

Afonso C. , Oliveira A. : Solar chimneys: simulation and experiment: Energy Buildings 2000;32:71-79.

12.

Bansal NK , Mathur R. , Bhandari MS : Solar chimney for enhanced stack ventilation: Building Environ 1993;28:373-377.

13.

Sandberg M. , Moshfegh B. : Ventilated-solar roof airflow and heat transfer investigation: Renewable Energy 1998; 15:287-292.

14.

Chen ZD , Bandopadhayay P. , Halldorsson J. , Byrjalsen C. , Heiselberg P. , Li Y. : An experimental investigation of a solar chimney model with uniform wall heat flux: Building Environ 2003;38:893-906.

15.

Hirunlabh J. , Kongduang W. , Namprakai P. , Khedari J. : Study of natural ventilation of houses by a metallic solar wall under tropical climate: Renewable Energy 1999;18:109-119.

16.

Ong KS : A mathematical model of a solar chimney: Renewable Energy 2003; 28:1047-1060.

17.

Spalding DB : The PHOENICS Encyclopedia. UK, CHAM Ltd., 1994.