Natural Ventilation of Toilet Units in K–12 School Restrooms Using CFD

Yi-Pin Lin

doi:10.3390/en14164792

Abstract

In this study, the influence of architectural design parameters (the exterior window area, the wall height at a corridor-side, and the door gap of a toilet unit) on the airflow patterns and malodorous volatile substance (acetic acid) distributions within toilet units were investigated via computational fluid dynamics (CFD), with the restrooms in K–12 public schools (kindergarten through grade 12) of Taiwan as research objects. The results show that when there is a 2 m/s north wind in winter, all the cases exceed the required 12 air changes per hour (ACH), and most are above 43.75 ACH. When there is a 0.5 m/s south wind in summer, nearly half of the cases fail to reach 12 ACH. Maintaining an adequate natural ventilation rate and an acceptable level of odor pollution through passive design and architectural design is difficult. Thinking about how to improve the ventilation efficiency of toilet units with the aid of simple, appropriate, and energy-saving mechanical ventilation approaches is necessary.

Highlights

In Taiwan, toilets in K–12 public schools (kindergarten (K) and grades 1–12) are difficult to manage because they are frequently used and open to the public
With the restrooms in the K–12 public schools of Taiwan as research objects, the influence of architectural design parameters, such as the window area, the height of the side wall on the corridor side, and the door gap of a toilet unit, on the natural ventilation performance and malodorous volatile substance distributions within toilet units were analyzed through computational fluid dynamics (CFD)
To reduce the solar heat gain of a building and improve the natural ventilation efficacy, the long axis of most K–12 public school buildings in Taiwan is parallel with the east to west direction, with restrooms on both sides

Summary

Introduction

In Taiwan, toilets in K–12 public schools (kindergarten (K) and grades 1–12) are difficult to manage because they are frequently used and open to the public. Those that have been used for years often have problems such as foul odor, poor ventilation, deterioration of building materials, etc. There are limited studies in the literature on restroom ventilation, including the overall ventilation performance of restrooms, the efficiency of restroom components (toilet, fan), and indoor air quality (IAQ) measurements. The results showed that negative pressure could be used to prevent odors from drifting to adjacent rooms, and both increasing air exhaust and decreasing the distance between exhaust vents and toilets could improve indoor pollutant removal rate and ventilation rate. Tung et al [2]

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Results

Conclusion