scholarly journals Practical Impact of the COVID-19 Pandemic on Indoor Air Quality and Thermal Comfort in Kindergartens. A Case Study of Slovenia

2021 ◽  
Vol 18 (18) ◽  
pp. 9712
Author(s):  
Vesna Lovec ◽  
Miroslav Premrov ◽  
Vesna Žegarac Leskovar
Keyword(s):  
Carbon Dioxide ◽  
Air Quality ◽  
Thermal Comfort ◽  
Indoor Air Quality ◽  
Air Temperature ◽  
Indoor Air ◽  
Carbon Dioxide Concentration ◽  
Building Stock ◽  
Practical Impact

The experimental monitoring of carbon dioxide concentration was carried out in kindergartens in Slovenia, together with indoor air temperature and relative humidity, before and during the COVID-19 pandemic. The aim of the research was to estimate the practical impact of the pandemic on indoor air quality and thermal comfort. The case study sample included buildings with different architectural typology, which are predominantly present in the building stock of Slovenia. The monitoring process lasted for 125 days before and during the COVID-19 pandemic. The results have shown a better indoor air quality in kindergartens during the pandemic, mostly due to ventilation protocols and almost imperceptibly changed indoor air temperature. The COVID-19 pandemic affected air quality in kindergarten classrooms in Slovenia by reducing the average carbon dioxide concentration when children were present in classrooms by 30%.

CFD Analysis on Thermal Comfort and Indoor Air Quality Affected by Partitions in Air-Conditioned Building

2016 ◽  
Vol 836 ◽  
pp. 121-126
Author(s):  
Pradip Aryal ◽  
Thananchai Leephakpreeda
Keyword(s):  
Carbon Dioxide ◽  
Air Quality ◽  
Thermal Comfort ◽  
Indoor Air Quality ◽  
Indoor Air ◽  
Carbon Dioxide Concentration ◽  
Average Concentration ◽  
Cfd Analysis ◽  
Carbon Dioxide Concentrations

This paper presents a CFD analysis on thermal comfort and indoor air quality affected by partitions in an air-conditioned building. CFD experiments are carried out to simulate variables of indoor air before/after installation or removal of partitions. Accordingly, the Predicted Mean Vote (PMV) is determined as an indicator of thermal comfort while the carbon dioxide concentration within an air-conditioned space is used for the assessment of indoor air quality. Some simulated results are validated by measurements with good agreement where a case study is conducted in an air-conditioned space of a library. With the proposed methodology, it can be recommended in a case study that the significant effects of partition on thermal comfort are observed where the area with neutral sensation and slightly-cool sensation reduces significantly. The occupants feel uncomfortably cold after installing partition. The carbon dioxide concentrations slightly increase in some areas but the average concentration remains acceptable according to ASHRAE standard. Without the reinforcement of the air-conditioning units, the installation of partition at the desired location is not encouraged regarding to occupant’s thermal comfort and indoor air quality.

scholarly journals Mitigation Strategies for Overheating and High Carbon Dioxide Concentration within Institutional Buildings: A Case Study in Toronto, Canada

Buildings ◽  
2020 ◽  
Vol 10 (7) ◽  
pp. 124 ◽  
Author(s):  
Claire Tam ◽  
Yuqing Zhao ◽  
Zaiyi Liao ◽  
Lian Zhao
Keyword(s):  
Carbon Dioxide ◽  
Air Quality ◽  
Indoor Air Quality ◽  
Air Temperature ◽  
Indoor Air ◽  
Indoor Environment ◽  
Thermal Conditions ◽  
Co2 Concentration ◽  
Hvac System

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.

Effects of Partition on Thermal Comfort, Indoor Air Quality, Energy Consumption, and Perception in Air-Conditioned Buildings

2016 ◽  
Vol 138 (5) ◽  
Author(s):  
Pradip Aryal ◽  
Thananchai Leephakpreeda
Keyword(s):  
Carbon Dioxide ◽  
Energy Consumption ◽  
Air Quality ◽  
Thermal Comfort ◽  
Indoor Air Quality ◽  
Indoor Air ◽  
Energy Savings ◽  
Carbon Dioxide Concentration ◽  
Peak Time ◽  
Cfd Analysis

This research is to assess effects of a partition on thermal comfort, indoor air quality (IAQ), energy consumption, and perception in an air-conditioned space via computational fluid dynamics (CFD) analysis. The variables of indoor air are numerically determined before/after installation/removal of a partition. Accordingly, predicted mean vote (PMV) of thermal comfort, carbon dioxide concentration, rate of energy consumption in making up air, and an overall perception index are proposed to quantify effects in a partitioned space. For a case study, a partition is used to tightly separate a study area from a rest area in a library during peak time. The CFD analysis is performed so that the mean differences between the measured and simulated variables at 14 locations are less than 5%. After partitioning in the CFD analysis, it is found that the average PMV value decreases to −1.4 in the rest area, and it remains at −0.7 in the study area where occupants perceive a slightly cool sensation. In the study area, the carbon dioxide concentration increases to 450–500 ppm, while the rate of energy consumption increases by 8.3%. From the overall perception index of 0.9, the occupants feel spacious in the partitioned areas. Therefore, installing the partition is encouraged with the recommendation that cooling supply can be reduced for energy savings. It is apparent that the proposed methodology yields quantitative indicators for decision making of installation/removal of partitions. The interior investigation of partitions in buildings can be performed before making real physical changes.

scholarly journals DESIGNING A SMALL CLIMATE CHAMBER TO CHARACTERIZE PEOPLE AS A SOURCE OF DETERIORATION OF INDOOR AIR QUALITY BY RESPIRATION

2019 ◽  
Vol 7 ◽  
pp. 954-959 ◽  
Author(s):  
Detelin Ganchev Markov ◽  
Sergey Mijorski ◽  
Peter Stankov ◽  
Iskra Simova ◽  
Radositna A. Angelova ◽  
...  
Keyword(s):  
Carbon Dioxide ◽  
Water Vapor ◽  
Air Quality ◽  
Indoor Air Quality ◽  
Indoor Air ◽  
Carbon Dioxide Concentration ◽  
Air Distribution ◽  
Vapor Concentration ◽  
Cfd Simulations ◽  
Climate Chamber

: People are one of the sources for deterioration of the indoor air quality. They worsen indoor air quality by their presence (respiration, bio-effluents), activities and habits. Through respiration, people decrease the oxygen concentration in the air of the occupied space and increase carbon dioxide and water vapor concentration in the indoor air as well as its temperature. The goal of the AIRMEN project is to find out if the rate of consumption of oxygen and emission of carbon dioxide (and water vapor) by people depends on the indoor air temperature as well as carbon dioxide concentration in the inhaled air. In order to achieve this goal a small climate chamber must be designed and constructed which allows for controlling and measuring both inflow and exposure parameters as well as for measuring outflow parameters. The principal goal of this paper is to present some important details, obtained by CFD simulations, from the design process of the climate chamber which precondition the air distribution in the chamber and hence the exposure parameters.

scholarly journals Analysis of Carbon Dioxide Concentration Prediction Model and Diffusion Tendency of Expiratory by Simultaneous Multipoint Sensing

2020 ◽  
Vol 10 (13) ◽  
pp. 4631
Author(s):  
Motokazu Moritani ◽  
Norifumi Watanabe ◽  
Kensuke Miyamoto ◽  
Kota Itoda ◽  
Junya Imani ◽  
...  
Keyword(s):  
Carbon Dioxide ◽  
Air Quality ◽  
Prediction Model ◽  
Indoor Air Quality ◽  
Indoor Air ◽  
Carbon Dioxide Concentration ◽  
Predicted Values ◽  
Carbon Dioxide Co2 ◽  
Intellectual Activities ◽  
And Diffusion

Recent indoor air quality studies show that even 1000 parts per million (ppm) concentration of Carbon Dioxide (CO2) has an adverse effect on human intellectual activities. Therefore, it is required to keep the CO 2 concentration below a certain value in a room. In this study, in order to analyze the diffusion tendency of carbon dioxide by breathing, we constructed a simultaneous multi-point sensing system equipped with a carbon dioxide concentration sensor to measure indoor environment. Furthermore, it was evaluated whether the prediction model can be effectively used by comparing the prediction value by the model and the actually measured value from the sensor. The experimental results showed that CO 2 by exhaled breathing diffuses evenly throughout the room regardless of the sensor’s relative positions to the human test subjects. The existing model is sufficiently accurate in a room which has above at least a 0.67 cycle/h ventilation cycle. However, there is a large gap between the measured and the model’s predicted values in a room with a low ventilation cycle, and that suggests a measurement with a sensor still is necessary to precisely monitor the indoor air quality.

scholarly journals Method for Estimation of CO2 Gains from Persons in Builidings

Proceedings ◽  
2018 ◽  
Vol 2 (20) ◽  
pp. 1309 ◽  
Author(s):  
Antonio Rodero ◽  
Dorota Anna Krawczyk
Keyword(s):  
Carbon Dioxide ◽  
Air Quality ◽  
Indoor Air Quality ◽  
Indoor Air ◽  
Carbon Dioxide Concentration ◽  
Co2 Concentration ◽  
Males And Females ◽  
Sources Of Co2

Carbon dioxide concentration is an important parameter to know Indoor Air Quality of a building. One of the most important sources of CO2 in poor ventilated building is human activity. This work presents a method for experimental determination of human CO2 generation rate based on measuring of time evolution of indoor CO2 concentration. The method is applied to 5 rooms of an educational building from Bialystok (Poland). Similar carbon dioxide gains were obtained in all rooms, around 0.0046 L/s, which correspond to theoretical CO2 generation rates of a sedentary activity for persons, males and females, between 21–30 years old, characteristics of occupants of analyzed rooms.

scholarly journals Thermal comfort analysis in office buildings with different air-conditioning systems

2018 ◽  
Vol 9 (1) ◽  
pp. 59-63 ◽  
Author(s):  
J. Szabo ◽  
L. Kajtar
Keyword(s):  
Air Quality ◽  
Thermal Comfort ◽  
Indoor Air Quality ◽  
Indoor Air ◽  
Air Conditioning ◽  
Carbon Dioxide Concentration ◽  
Comfort Level ◽  
Office Buildings ◽  
Ducted Fan ◽  
Air Conditioning Systems

It is a prime aim to ensure a suitable comfort level in case of office buildings. The productivity of office employees is directly influenced by the comfort. Thermal discomfort and poor indoor air quality deteriorate the intensity and quality of human work. We investigated the comfort in office buildings with on-site measurements during the summer season. The office buildings were operating with different HVAC (Heating, Ventilating and Air-Conditioning) systems: ducted fan-coil with suspended ceiling, installation, non-ducted fan-coil with floor-mounted installation, active chilled beam with fresh air supply. We evaluated the thermal comfort under PMV (Predicted Mean Vote), PPD (Predicted Percentage of Dissatisfied), the local discomfort based on DR (Draught Rate) and the IAQ (Indoor Air Quality) based on carbon dioxide concentration. The comfort measurements were evaluated. The measurements were evaluated with scientific research methods, comfort categories based on the requirements of CR 1752. The results of this comparison were presented in this article.

Application of solar radiation to the ventilation of an experimental chamber through a set of dual skin facades

2020 ◽  
pp. 25-35
Author(s):  
Eusébio Conceição ◽  
João Gomes ◽  
Mª Manuela Lúcio ◽  
Mª Inês Conceição ◽  
Hazim Awbi
Keyword(s):  
Air Quality ◽  
Thermal Comfort ◽  
Indoor Air Quality ◽  
Integral Equations ◽  
Indoor Air ◽  
Carbon Dioxide Concentration ◽  
Integral Model ◽  
Experimental Chamber ◽  
Airflow Rate ◽  
Numerical Work

The aim of this numerical work is to evaluate the influence of a set of three Dual Skin Façades (DSF) on the thermal comfort and air quality inside a virtual occupied experimental chamber under various airflow rates. Each DSF is constituted by two transparent glasses and an adjustable venetian blind located in the air channel existing between the two surfaces. A system of energy balance integral equations is used to estimate the air temperature inside the virtual chamber and DSF and the temperature in the different elements of the virtual chamber and a system of mass balance integral equations is used to estimate the contaminants inside the virtual chamber and the DSF. The uncomfortable hours integral model is used to evaluate the total number of uncomfortable hours due to warm and cold indoor conditions and also due to indoor air quality conditions. The acceptable levels of indoor thermal comfort, evaluated by the Predicted Mean Vote index, must be within category C of ISO 7730 standard. The acceptable levels of indoor air quality, evaluated by the carbon dioxide concentration, must be below the limit of 1800 mg/m3 proposed by the ASHRAE 62.1 standard. Three airflow rates were chosen: 0.0389 m3/s, 0.0778 m3/s and 0.1167 m3/s. The airflow that guarantees, at the same time, the best indoor air quality and thermal comfort levels is obtained through the minimization of the total number of uncomfortable hours. As best option, it was obtained the airflow rate of 0.1167 m3/s.

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