Measurement and Simulation of Indoor Air Quality and CO2 Concentration in a Hotel Room

Author(s):  
Ehsan Asadi ◽  
Manuel Gameiro da Silva ◽  
Jose´ J. Costa

Indoor air quality (IAQ) is nowadays universally recognized as an important issue that affects the comfort and health of people, as well as their productivity. This paper describes the relationship of indoor CO2 concentration to building air quality and ventilation, with a focus on how CO2 can be used to evaluate and predict air quality and ventilation performance, namely the infiltration airflow rate. Besides it shows the ability of ESP-r building simulation software for predicting the CO2 concentration and the air exchange rate in a building. For this purposes a room of a hotel located in the urban area of Coimbra was chosen. The developed simulation model was then validated against empirical results. It was shown that a fair degree of agreement between ESP-r results and the experimental observation exist for the zones. High accuracy of the simulation model showed that building simulation software, namely ESP-r can provide a better understanding of indoor environmental conditions and be a powerful tool in finding the best modification measures for improving the indoor air quality in a building.

2020 ◽  
Vol 38 (9A) ◽  
pp. 1257-1275
Author(s):  
Wisam M. Mareed ◽  
Hasanen M. Hussen

 Elevated CO2 rates in a building affect the health of the occupant. This paper deals with an experimental and numerical analysis conducted in a full-scale test room located in the Department of Mechanical Engineering at the University of Technology. The experiments and CFD were conducted for analyzing ventilation performance. It is a study on the effect of the discharge airflow rate of the ceiling type air-conditioner on ventilation performance in the lecture room with the mixing ventilation. Most obtained findings show that database and questionnaires analyzed prefer heights between 0.2 m to 1.2 m in the middle of an occupied zone and breathing zone height of between 0.75 m to 1.8 given in the literature surveyed. It is noticed the mismatch of internal conditions with thermal comfort, and indoor air quality recommended by [ASHRAE Standard 62, ANSI / ASHRAE Standard 55-2010]. CFD simulations have been carried to provide insights on the indoor air quality and comfort conditions throughout the classroom. Particle concentrations, thermal conditions, and modified ventilation system solutions are reported.


2021 ◽  
Vol 13 (8) ◽  
pp. 4139
Author(s):  
Muriel Diaz ◽  
Mario Cools ◽  
Maureen Trebilcock ◽  
Beatriz Piderit-Moreno ◽  
Shady Attia

Between the ages of 6 and 18, children spend between 30 and 42 h a week at school, mostly indoors, where indoor environmental quality is usually deficient and does not favor learning. The difficulty of delivering indoor air quality (IAQ) in learning facilities is related to high occupancy rates and low interaction levels with windows. In non-industrialized countries, as in the cases presented, most classrooms have no mechanical ventilation, due to energy poverty and lack of normative requirements. This fact heavily impacts the indoor air quality and students’ learning outcomes. The aim of the paper is to identify the factors that determine acceptable CO2 concentrations. Therefore, it studies air quality in free-running and naturally ventilated primary schools in Chile, aiming to identify the impact of contextual, occupant, and building design factors, using CO2 concentration as a proxy for IAQ. The monitoring of CO2, temperature, and humidity revealed that indoor air CO2 concentration is above 1400 ppm most of the time, with peaks of 5000 ppm during the day, especially in winter. The statistical analysis indicates that CO2 is dependent on climate, seasonality, and indoor temperature, while it is independent of outside temperature in heated classrooms. The odds of having acceptable concentrations of CO2 are bigger when indoor temperatures are high, and there is a need to ventilate for cooling.


2021 ◽  
Vol 13 (11) ◽  
pp. 6188
Author(s):  
Sungwan Son ◽  
Choon-Man Jang

For students, who spend most of their time in school classrooms, it is important to maintain indoor air quality (IAQ) to ensure a comfortable and healthy life. Recently, the ventilation performance for indoor air quality in elementary schools has emerged as an important social issue due to the increase in the number of days of continuous high concentrations of particulate matter. Three-dimensional numerical analysis has been introduced to evaluate the indoor airflow according to the installation location of return diffusers. Considering the possibility of the cross-infection of infectious diseases between students due to the direction of airflow in the classroom, the airflow angles of the average respiratory height range of elementary school students, between 1.0 and 1.5 m, are analyzed. Throughout the numerical analysis inside the classroom, it is found that the floor return system reduces the indoor horizontal airflow that causes cross-infection among students by 20% compared to the upper return systems. Air ventilation performance is also analyzed in detail using the results of numerical simulation, including streamlines, temperature and the age of air.


Author(s):  
M. F. Mohamed ◽  
M. Behnia ◽  
S. King ◽  
D. Prasad

Cross ventilation is a more effective ventilation strategy in comparison to single-sided ventilation. In the NSW Residential Flat Design Code1 (RFDC) the majority of apartments are required to adopt cross ventilation. However, in the case of studio and one-bedroom apartments, it is acknowledged that single-sided ventilation may prevail. Deep plan studio and one-bedroom apartments may achieve lower amenity of summer thermal comfort and indoor air quality where mechanical ventilation is not provided by air conditioning. Since compliance with the code may allow up to 40% of apartments in a development in Sydney to be single sided, it is important to understand the natural ventilation performance of such apartments. The objective of this paper is to investigate the natural ventilation potential in single-sided ventilated apartments to improve indoor air quality and thermal comfort. This investigation includes simulating various facade treatments involving multiple opening and balcony configurations. Balcony configurations are included in this study because, in Sydney, a balcony is a compulsory architectural element in any apartment building. The study uses computational fluid dynamics (CFD) software to simulate and predict the ventilation performance of each apartment configuration. This study suggests that properly configured balconies and openings can significantly improve indoor ventilation performance for enhanced indoor air quality and thermal comfort, by optimizing the available prevailing wind. However, it is important to note that inappropriately designed fac¸ade treatments also could diminish natural ventilation performance.


2014 ◽  
Vol 29 (suppl.) ◽  
pp. 52-58
Author(s):  
Franz Roessler ◽  
Jai Azzam ◽  
Volker Grimm ◽  
Hans Hingmann ◽  
Tina Orovwighose ◽  
...  

The energy conservation regulation provides upper limits for the annual primary energy requirements for new buildings and old building renovation. The actions required could accompany a reduction of the air exchange rate and cause a degradation of the indoor air quality. In addition to climate and building specific aspects, the air exchange rate is essentially affected by the residents. Present methods for the estimation of the indoor air quality can only be effected under test conditions, whereby the influence of the residents cannot be considered and so an estimation under daily routine cannot be ensured. In the context of this contribution first steps of a method are presented, that allows an estimation of the progression of the air exchange rate under favourable conditions by using radon as an indicator. Therefore mathematical connections are established that could be affirmed practically in an experimental set-up. So this method could provide a tool that allows the estimation of the progression of the air exchange rate and in a later step the estimation of a correlating progression of air pollutant concentrations without limitations of using the dwelling.


Author(s):  
Edgar C. Ambos ◽  
Evan Neil V. Ambos ◽  
Lanndon A. Ocampo

Due to its significant role in improving indoor air quality, displacement ventilation system is widely adopted in current literature. This paper proposes a displacement ventilation system for room conditions with ceilings that are relatively low, internal heat load could be high, walls could be sunlit, and occupants doing the low physical activity. These conditions are prevalent in the Philippines, being a tropical country. Input parameters to the design process such as heat load, the height of the ceiling, comfort, and indoor air quality requirements were generated, and the main output parameters are the stratification height and ventilation airflow rate. To demonstrate the proposed displacement ventilation system, four cases were generated. Results show that the ventilation airflow rates obtained from the four cases were greater than the minimum outdoor air requirements for health in conference rooms and large assembly areas which are 17.5 and 3.5 liters/sec*person respectively, for smoking and no smoking rooms.


Buildings ◽  
2020 ◽  
Vol 10 (7) ◽  
pp. 124 ◽  
Author(s):  
Claire Tam ◽  
Yuqing Zhao ◽  
Zaiyi Liao ◽  
Lian Zhao

Indoor air quality and thermal conditions are important considerations when designing indoor spaces to ensure occupant health, satisfaction, and productivity. Carbon dioxide (CO2) concentration and indoor air temperature are two measurable parameters to assess air quality and thermal conditions within a space. Occupants are progressively affected by the indoor environment as the time spent indoors prolongs. Specifically, there is an interest in carrying out investigations on the indoor environment through surveying existing Heating, Ventilation, Air Conditioning (HVAC) system operations in classrooms. Indoor air temperature and CO2 concentration in multiple lecture halls in Toronto, Canada were monitored; observations consistently show high indoor air temperature (overheating) and high CO2 concentration. One classroom is chosen as a representative case study for this paper. The results verify a strong correlation between the number of occupants and the increase in air temperature and CO2 concentration. Building Energy Simulation (BES) is used to investigate the causes of discomfort in the classroom, and to identify methods for regulating the temperature and CO2 concentration. This paper proposes retro-commissioning strategies that could be implemented in institutional buildings; specifically, the increase of outdoor airflow rate and the addition of occupancy-based pre-active HVAC system control. The proposed retrofit cases reduce the measured overheating in the classrooms by 2-3 °C (indoor temperature should be below 23 °C) and maintain CO2 concentration under 900 ppm (the CO2 threshold is 1000 ppm), showing promising improvements to a classroom’s thermal condition and indoor air quality.


Buildings ◽  
2019 ◽  
Vol 9 (5) ◽  
pp. 110 ◽  
Author(s):  
Luca Stabile ◽  
Angelamaria Massimo ◽  
Laura Canale ◽  
Aldo Russi ◽  
Alexandro Andrade ◽  
...  

Most of the school buildings in Italy are high energy-demanding buildings with no ad-hoc ventilation systems (i.e., naturally-ventilated buildings). Therefore, reducing the heat losses of schools represent the main aspect to be dealt with. Nonetheless, the indoor air quality of the building should be simultaneously considered. Indeed, to date, energy consumptions and air quality are considered as incompatible aspects especially in naturally-ventilated buildings. The aim of the present paper is to evaluate the effect of different ventilation and airing strategies on both indoor air quality and energy consumptions in high energy-demanding naturally-ventilated classrooms. To this purpose, an Italian test-classroom, characterized in terms of air permeability and thermophysical parameters of the envelope, was investigated by means of experimental analyses and simulations through CO2 mass balance equation during the heating season. The air quality was assessed in terms of indoor CO2 concentrations whereas the energy consumptions were evaluated through the asset rating approach. Results clearly report that not adequate indoor CO2 concentrations are measured in the classroom for free-running ventilation scenarios even in low densely populated conditions (2.2 m2 person−1), whereas scheduled airing procedures can reduce the indoor CO2 levels at the cost of higher energy need for ventilation. In particular, when airing periods leading to the air exchange rate required by standards are adopted, the CO2 concentration can decrease to values lower than 1000 ppm, but the ventilation losses increase up to 36% of the overall energy need for space heating of the classroom. On the contrary, when the same air exchange rate is applied through mechanical ventilation systems equipped with heat recovery units, the ventilation energy loss contribution decreases to 5% and the overall energy saving results higher than 30%. Such energy-saving was found even higher for occupancy scenarios characterized by more densely populated conditions of the classroom typically occurring in Italian classrooms.


2014 ◽  
Vol 40 (3) ◽  
pp. 259-268 ◽  
Author(s):  
Ana Maria da Conceição Ferreira ◽  
Massano Cardoso

Objective: To determine whether indoor air quality in schools is associated with the prevalence of allergic and respiratory diseases in children. Methods: We evaluated 1,019 students at 51 elementary schools in the city of Coimbra, Portugal. We applied a questionnaire that included questions regarding the demographic, social, and behavioral characteristics of students, as well as the presence of smoking in the family. We also evaluated the indoor air quality in the schools. Results: In the indoor air of the schools evaluated, we identified mean concentrations of carbon dioxide (CO2) above the maximum reference value, especially during the fall and winter. The CO2 concentration was sometimes as high as 1,942 ppm, implying a considerable health risk for the children. The most prevalent symptoms and respiratory diseases identified in the children were sneezing, rales, wheezing, rhinitis, and asthma. Other signs and symptoms, such as poor concentration, cough, headache, and irritation of mucous membranes, were identified. Lack of concentration was associated with CO2 concentrations above the maximum recommended level in indoor air (p = 0.002). There were no other significant associations. Conclusions: Most of the schools evaluated presented with reasonable air quality and thermal comfort. However, the concentrations of various pollutants, especially CO2, suggest the need for corrective interventions, such as reducing air pollutant sources and improving ventilation. There was a statistically significant association between lack of concentration in the children and exposure to high levels of CO2. The overall low level of pollution in the city of Coimbra might explain the lack of other significant associations.


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