School indoor air quality has become of concern recently in Korea. In this paper, it is intendedto investigate the ventilation performance and thermal comfort characteristics of a classroom,when an outdoor air system is installed in addition to a ceiling-mounted heat pump system.Experiments were conducted in a full-scale model classroom to collect experimental data tovalidate numerical schemes. Three-dimensional temperature distributions were measured withthermocouples distributed throughout the space, and ventilation effectiveness was measuredusing a tracer gas technique.
This paper presents the indoor air quality performance of a displacement ventilation system ina thermal chamber. This study consists of two sets of experiments. In the first experiment, thethermal chamber was operated under displacement ventilation (DV) mode with the relativehumidity (RH) set at about 65% while the ambient temperature (AT) at 1.3 m height variedfrom 22 to 26C. In the second experiment, all the conditions are the same except that theventilation strategy is changed to mixing ventilation (MV).
Natural controlled ventilation is often ignored when buildings are designed. It is importantthat architects, property developers both commercial and residential, designers, engineers andthe general public be aware of guidelines (readily available) for proper indoor air quality.Mechanical engineers should realize that introducing supplemental fresh air ventilation intoheating, ventilating and air conditioning (HVAC) systems aids in improving indoor air qualityand often maximizes the efficiency of the HVAC systems.
In the indoor air quality (IAQ) assessment of ventilated enclosures it is useful to know therelative influence of key boundary conditions on the personal exposure and ventilationeffectiveness, for instance as a source of information on where to allocate the greatest effortin the design phase. CFD is used to predict ventilation effectiveness and personal exposure tocontaminant sources in a displacement ventilated room subject to variation of several keyboundary conditions.
After several cases of health problems in French schools, a methodology for health riskassessment related to indoor air quality (IAQ) was required. Based on measuredconcentrations in schools where acute symptoms possibly due to exposure to airborne sensoryirritants were reported, an index quantifying the sensory irritation potential was built andused. This paper focuses on one classroom where the index was successively applied withoutany ventilation system, after the implementation of passive ventilation grids and with amechanically controlled ventilation.
This paper reviews the previous attempts to evaluate the Indoor Air Quality (IAQ),investigates previously proposed IAQ factors and analyses the evaluation methods of thesefactors. The present work also introduces a new hypothesis of the optimum HVAC airsidesystem design of the surgical operating theatres to achieve the comfort and hygiene levels.The present work is devoted to propose and formulate a new scale capable of adequatelyevaluating the airflow pattern in the surgical operating theatres. The proposed new scale isproposed to cover the local and overall air quality evaluations.
Split system air-conditioning units are commonly employed in residential buildings inthe tropics due to their convenience in terms of energy conservation, aesthetics,flexibility, acoustic performance and ease of operation. This paper presents ourfindings from a recent study of the IAQ and ventilation characteristics in a masterbed-room of a condominium unit in Singapore, employed with a split system airconditioningunit. The attached bathroom is equipped with an exhaust fan, whoseoperation and its impact on the resulting IAQ and ventilation characteristics was alsostudied.
The performance of a Personalized Ventilation (PV) system with regard to air qualityperceived by people was studied at three room temperature levels: 23, 26 and 29C. Thirtyhuman subjects participated in the experiment. The system supplied both isothermal (23, 26,29C) and non-isothermal (23C) outdoor air from an outlet attached to a moveable arm. Thesubjects were delegated with control of both airflow velocity and its direction. Physicalmeasurements performed with a breathing thermal manikin were used to explain the resultsfrom the human subject experiments.
Continuous measurements have been operated on 28 identical low energy houses near Leipzig (Germany) during two years.The houses face due south, have two levels and one occupied attic, with a total aera of 147 m2. Heating period is from September to May. All houses except 2 were equipped with different mechanical ventilation systems, providing about 180 m3/hr of fresh air : central balanced flue systems with heat recovery, air heating system with heat recovery, central exhaust ventilation with heat recovery by heat pump, room mechanical ventilation systems.
The system of education in Poland is affected by rapid and deep political, organizational,demographic and financial changes. Although requirements for indoor air quality aredescribed in detail in Polish building codes and standards, the real state of indoor environmentin classrooms is not well documented. However, published studies show that in schools withconventional stack ventilation indoor air quality is rather poor. Unintentionally, very oftenproblems are related to modernized buildings where energy conservation measures have beenapplied.
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