AR 600 XB
Methods to reduce CO2 concentration in classrooms using hybird ventilation
Yousef Khoja Department of Architecture Faculty of Environmental Design King Abdulaziz University
Contents
-Introduction
-Background
-Problem Statement -point of departure
-Research Question
-Purpose
-Literature Review -Methodology -Scenario
1 2 3 3 3 3 4-12 13-18 19-37
-Recommendations
38
-Conclusion
39
Methods to reduce CO2 concentration in classrooms using hybird ventilation
Introduction Achieving the highest levels of education and culture is a goal for all contemporary societies. The competition between contemporary societies is based on this basis, therefore, the need to review and continuously develop the educational systems and educational establishments was a necessity. The difficulties faced by contemporary societies are the large number of population densities and the increase in the need to provide education to all components of society and all people equally and fairly, but this increase in numbers. It also resulted in the need to develop educational facilities to accommodate these numbers and suit the current conditions of such communities. This increase is the lack of quality of the internal space in general and the lack of indoor air quality in particular. Educational performance and public health levels within these internal spaces, and many studies have shown that the rise of carbon dioxide in the classroom leads to health problems and affect the educational levels of the student
Methods to reduce CO2 concentration in classrooms using hybird ventilation
1
Background
Sick building syndrome (SBS) is a medical condition where people in a building suffer from symptoms of illness or feel unwell The symptoms tend to increase in severity with the time people spend in the building, and improve over time or even disappear when people are away from the building. The main identifying observation is an increased incidence of complaints of symptoms such as headache, eye, nose, and throat irritation, fatigue, and dizziness and nausea. These symptoms appear to be linked to time spent in a building, though no specific illness or cause can be identified. SBS is also used interchangeably with "building-related symptoms", which orients the name of the condition around patients rather than a "sick" building. A 1984 World Health Organization (WHO) report suggested up to 30% of new and remodeled buildings worldwide may be subject of complaints related to poor indoor air quality. Sick building causes are frequently pinned down to flaws in the heating, ventilation, and air conditioning (HVAC) systems. However, there have been inconsistent findings on whether air conditioning systems result in SBS or not.Other causes have been attributed to contaminants produced by outgassing of some types of building materials, volatile organic compounds (VOC), improper exhaust ventilation of ozone (byproduct of some office machinery), light industrial chemicals used within, or lack of adequate fresh-air intake/air filtration . Methods to reduce CO2 concentration in classrooms using hybird ventilation
2
points of departure
Keywords
Increase number of students
limitation of Existing mechanical system the need of optimization and utilize natural ventilation
Education
Indoor Environmental Quality
lack of operable windows
Elements need to be optimized and untargeted with the ventilation system, in times of acceptable outdoor temperature
Problem Statement
Achieving in optimized hybrid ventilation system that helps provide and Increases indoor air quality with low mechanical complicity and energy consumption
Comfort level in the classroom
Students Performance
Number of students
Health in the classroom
Research Question
Can a set of hybrid ventilation solution help achieving the desired goal ?
Purpose
High rate of carbon dioxide
Indoor Air Quality
Development of the essential criteria to hybrid ventilation methods that can be considered in the improvement of IEQ of similar cases Methods to reduce CO2 concentration in classrooms using hybird ventilation
3
Literature Review
Findings
Related to research problem and the impact of high level of carbon dioxide Reference Shedenll et al. 2004b.
Gaihre et al. 2014.
MacNaughton et al. 2017.
Simon et al. 2010.
Academic outcomes/effect 1000 ppm increase in dCO2 associated with 10–20% student absent rate (P < 0.05).
100 ppm increase in CO2 was linked to 0.2% (0.4 days/session) students’ absenteeism.
1 μg/m3 increase in PM2.5 per session was associated with 1.58% (P < 0.0001) increase in students’ chronic absenteeism. 0.15 increase in NDVI during school year was related to 2.6% (P < 0.0001) decrease in chronic absent rate. Students’ absenteeism was linked to ventilation inadequacy (OR = 3.10; 95% CI = 1.79-5.37), mold presence (OR = 2.33; 95% CI = 1.34-3.68), humidity (OR = 3.07; 95% CI = 1.37-6.89) and adverse school conditions (OR = 2.97; 95% CI = 1.84-4.79) respectively.
Methods to reduce CO2 concentration in classrooms hybird using ventilation
The rise in CO2 is related to the high level of absenteeism among students The high level of carbon dioxide affects students' cognitive performance and mathematics and reading Skills The increase in ventilation levels increases activity and concentration among students The high level of carbon dioxide causes health damage including allergies and lung diseases
4
Literature Review
Related to research problem and the impact of high level of carbon dioxide Reference HaverinenShaughnes sy et al. 2011.
Hutter et al. 2013.
Bakó-Biró et al. 2012.
Academic outcomes/effect Math and reading achievement was increased by 2.9% (95%CI 0.9–4.8%) and 2.7% (95% CI 0.5–4.9%) respectively per each 1 l/s per person increase in ventilation rate. Cognitive performance was correlated with TCEP (r = -.149, P = .002), and CO2 (r = -.102, P = .034) in classroom.
Higher ventilation increases students’ responses and accuracy by 15% for word recognition, 8% for picture memory, 2.7% for color word vigilance
Findings The high level of carbon dioxide affects students' cognitive performance and mathematics and reading Skills The increase in ventilation levels increases activity and concentration among students
and 2.2% for choice reaction. HaverinenShaughnessy & Shaughnessy 2015.
Mathematics test score increased by 0.5% for 1 l/s-person increase in ventilation. A similar result was achieved for 1oC reduction of classroom temperature.
Methods to reduce CO2 concentration in classrooms using hybird ventilation
5
Literature Review
Findings
Related to research problem and the impact of high level of carbon dioxide Reference
Annesi-Maesano et al. 2012.
Health outcomes/effect Rhino-conjunctivitis associated with high concentration of formaldehyde (OR 1.19; 95% CI 1.04 to 1.36). The prevalence of asthma associated with high concentration of PM2.5 (OR 1.21; 95% CI 1.05 to 1.39), Aldehyde (OR 1.22; 95% CI 1.09 to 1.38) and NO2 (OR 1.16; 95% CI
The high level of carbon dioxide causes health damage including allergies and lung diseases
0.95 to 1.41).
Kim et al. 2007.
Mi et al. 2006.
Wheezing, daytime breathlessness, nocturnal breathlessness and asthma associated with MVOCs (e.g. Isobutanol) OR 2.74 (0.71–10.57), 2.05 (0.30–13.87), 7.23 (0.60–87.16) & 1.43 (0.35–5.87) respectively.
Asthma attacks associated with mold (OR 2.40: P < 0.05). Daytime breathlessness associate with temperature related to (OR 1.26: P < 0.001). Current asthma associated with CO2 (OR 1.18 for 100 ppm: P < 0.01) and NO2 (OR 1.51 for 10 μg/m3: P < 0.01)
Methods to reduce CO2 concentration in classrooms using hybird ventilation
6
Literature Review
Findings
Related to research problem and the impact of high level of carbon dioxide Reference Mendell et al. 2013
Ferreira & Cardoso 2014.
Health outcomes/effect Studentsâ&#x20AC;&#x2122; illness absence increases with a reduced ventilation rate/student that is below California standard (7.1 l/s-person).
The high level of carbon dioxide causes health damage including allergies and lung diseases
2.2% of students had chronic bronchitis (P > 0.05), 15.2% had wheezing (P > 0.05), 26.1% had sneezing attack (P > 0.05), 18.9% had rhinitis (P > 0.05), 16.1% had cough (P > 0.05), and 10.1% had breathing difficulties (P > 0.05).
Bidassey-Manilal et al. 2016
97%, 97% and 94% of students were tired, lost concentration and sleepy due to thermal discomfort.
Methods to reduce CO2 concentration in classrooms using hybird ventilation
7
Findings
Literature Review Related to research problem Epidemiological study in Saudi Arabia Reference Nahhas M1, Bhopal R, Anandan C, Elton R, Sheikh A. 2012 Mohammed O Al Ghobain, Mohamad S Al-Hajjaj & Mohamad S Al Moamary , 2012 Amin TT1, Ali A, Kaliyadan F. 2011
Elham Jenahi, Mohamed S. Khalil, and Hassan Bella,2012
Abdulrhman M. Al-Sughayr Mazen S. Ferwana, 2012 M.O. Al-Ghobain1 M.S. Al-Moamary1 , M.S. Al-Hajjaj1 , A.I. Al-Fayez2 and S.I. Basha2 , 2013
Conclusions Symptoms indicative of allergic disease are very common in primary school-aged children in Madinah, Saudi Arabia, with figures comparable to the highest risk regions in the world The prevalence of asthma and associated symptoms in 16- to 18-year-old adolescents in Saudi Arabia is high, although it is within range of reported prevalence rates from various parts of the world. Both transmissible and non-transmissible skin disorders were frequently encountered among male primary school children in Al Hassa, Saudi Arabia. Both socio-demographic and hygiene correlates play a significant role in the development of these disorders.
Medical studies conducted in Saudi Arabia demonstrate a clear problem in schools due to poor quality of internal spaces in schools
It was concluded that the prevalence of ADHD in female primary schoolchildren is comparable with what has been reported in other studies. Some demographic factors should be taken into consideration when interpreting this result. Implications and recommendations to the concerned authorities are outlined to improve the health and educational care services to help these children. The adolescent age groups in our community had high rates of mental disorders, which required more attention from the family, as well as the educational and health institutes in our country
The present study demonstrated a high prevalence of rhinitis symptoms among 16 to 18 years old adolescents in Saudi Arabia. Rhinitis symptoms were more common in girls compared with boys. Further, the results indicated that rhinitis symptoms are also associated with a high frequency of asthma symptoms
Methods to reduce CO2 concentration in classrooms using hybird ventilation
8
Literature Review
Findings
Research on solutions to the problem of carbon dioxide and ventilation Reference
Conclusions -Air temperature and relative humidity are quite homogeneous and within adequate limits in both data-sets.
Ricardo M. S. F. Almeidaa,b,*, Vasco P. de Freitasb , ( 2015 )
-Non-refurbished classrooms present higher CO2 concentration levels.
Natural ventilation is a cheaper solution than mechanical ventilation but depends on external temperatures and the required thermal comfort levels
- The impact of the demand controlled ventilation system was obvious. - The positive impact of the refurbishment was confirmed by the survey. Students prefer the indoor air quality of the refurbished classrooms. - General knowledge of indoor air quality in schools is often very low. - It is important to propose optimization measures for reducing the CO2 concentrations and ensure thermal comfort.
It is important to raise awareness among students of the importance of ventilation and the quality of the inner space
- It is essential that users are aware that the quality of the indoor environment is important for their health, comfort and performance. Silvia Vilčekováa, Peter Kapalob, ĽudmilaMečiarováa, Eva KrídlováBurdováa,*, Veronika Imreczeováa ,( 2017 )
- Primary measure would be an increasing the intensity of natural ventilation during the lessons. Expensive but effective measure is mechanical ventilation and installation of CO2. - Presented results show that it is important to propose optimization measures for reducing the CO2 concentrations and ensure thermal comfort. Sensors as well as increasing the thermal persistence of building structures. -Future research work will be aimed at monitoring of indoor environmental quality in statistically significant set of buildings for education.
Methods to reduce CO2 concentration in classrooms using hybird ventilation
9
Findings
Literature Review Research on solutions to the problem of carbon dioxide and ventilation Reference Silvia Vilčekováa, Peter Kapalob, ĽudmilaMečiarováa, Eva KrídlováBurdováa,*, Veronika Imreczeováa ,( 2017 ) T. Colinart , M. Bendouma , P. Glouannec, 2018
Conclusions - The analysis focused on three points: the thermal performance of the envelope, the short-term moisture related durability and the indoor environmental quality (IEQ). - The investigation on IEQ underlined that hygrothermal comfort and indoor air quality are fulfilled most of the teaching time. However, unfavorable conditions were observed either early in the morning or after long occupation. Therefore, the comfort of the student and, thus, their health, attitude and performance can be - The air circulation in the classroom should be improved to remove heat as well as to increase the level of air velocity. Therefore, the exhaust fan and the air conditioning systems should be fixed and maintained. Besides that, the usage of cleaning agent that consists of high VOC should be minimized.
Nurul Malina Jamaludin, NorhayatiMahyuddin, Farid Wajdi Akashah,2017
The level of carbon dioxide is significantly reduced with the presence of suitable plants Combined ventilation system is one of the best solutions to the problem of ventilation and energy consumption
- Research has shown that other aspects of IEQ can also be improved with the help of indoor plants. Plants have always been good biological filters for both indoor and outdoor. They do not only serve as part of the landscaping, but also bring physiological benefits to humans. The focus of this study was to identify which tropical indoor plant in Malaysia has better efficiency in improving indoor air quality in educational building. The selection of plant to mitigate air pollution in a building does not only depend on their ability to clean the air but also on their growth habit, the ease of growing and maintaining them, their light requirement, and also their personal taste. - To provide further insights into how plants can reduce indoor pollution and improve our health, more plants need to be tested, and a more controlled environment is needed as well.
Methods to reduce CO2 concentration in classrooms using hybird ventilation
10
Literature Review
Findings
Research on solutions to the problem of carbon dioxide and ventilation Reference
ZsoltBakĂł-BirĂł,Pawel Wargocki,David P Wyon,2005
Conclusions The rate of CO2 production by occupants decreased significantly, by about 5%, when they were exposed to emissions from typical indoor pollution sources, compared to conditions in which these sources were not present. This effect can be caused by change in the breathing pattern (shallow breathing) or by a slower work rate in polluted air. Bothmchanges would cause a reduction in metabolic rate, which may be either the cause or the effect of reduced performance. - The results of the present investigation imply that an adequate ventilation rate in buildings is not only necessary to comply with human comfort requirements, but also to prevent a direct negative effect of a mediocre indoor air quality manifested in an alteration of the breathing pattern that may induce further physiological effects in humans, including symptoms similar to SBS.
Natural ventilation is a cheaper solution than mechanical ventilation but depends on external temperatures and the required thermal comfort levels
It is important to raise awareness among students of the importance of ventilation and the quality of the inner space
system comprising of decentralized ventilation units and a network of passive chilled beams.
SchlĂźter, 2017
- It was observed that the perceived thermal comfort and air quality satisfaction of the occupants were markedly higher in the 3for2 O_ce than in the Previous O_ce. This improvementwas attributed to be due, at least, to 1) enabling occupants to set their preferred indoor air temperature in the 3for2 O_ce, 2) ventilating the 3for2 O_ce with more outdoor air than minimally prescribed by local Standards, and 3) operating a decentralized system that could more precisely, and more uniformly, satisfy indoor environment set points. - One of the critical limitations of this study is its lack of a control group in the thermal comfort study of the new 3for2 space.
Methods to reduce CO2 concentration in classrooms hybird ventilation
11
Literature Review
Findings
Global standards for CO2 levels in interior spaces
Approximate Maximum Sedentary Carbon Dioxide Concentrations Associated With CEN 13779 Indoor Air Quality
Methods to reduce CO2 concentration in classrooms using hybird ventilation
Most of the global standards set 1000ppm as the maximum allowable level of carbon dioxide within the spaces, The European standard determines the level of renewable air per person per hour according to the level of carbon dioxide
12
Methodology
Research sample Analysis of the research sample
Description of the research sample Measurement
Analysis of measurement results
Calibration
Building simulation Model
Scenario
Find the best Scenario
Recommendations
Guideline Methods to reduce CO2 concentration in classrooms using hybird ventilation
13
Methodology
N
Description of the research sample Classroom located in the second floor of king abdulaziz university building number 535 floor area of the classroom are 7.5 * 9.14 m total number of occupants 40
classroom dimension classroom opening classroom Mechanical ventilation system Length =7.5m width =9.14m space =68.55m2 Height =3m volume =205.6m3
Window=3 doors= 1Double door
9.14m
central air handling unit vav system
7.5m Classroom Plan
3m
Classroom Interior Elevation Methods to reduce CO2 concentration in classrooms using hybird ventilation
14
Indoor Environmental Quality
Temperature
ventilation
Natural ventilation
Hybrid ventilation
Design variables Improvement in the mechanical ventilation system
Improving natural ventilation methods
change windows geometry
Lighting
Acoustics
Materials
Mechanical ventilation
students Schedule
Change in lecture times
The best number of students at the same time in the classroom
Scheduling the current window
Recommendations
Methods to reduce CO2 concentration in classrooms using hybird ventilation
15
N
Methodology Measurement
the measurements of CO2 concentrations in the indoor air perform in classroom university for one day and windows was closed during weekdays by using hobo mx CO2 logger measuring device the device took a reading every 10 minutes, floor area of the classroom are 7.5 * 9.14 m located in the second floor of the building , the measuring device placed in the center of the classroom in the height of 1.1m above the floor,using different ventilation systems by simulation using ida ice software
Classroom Plan
1.1m
Classroom Interior Elevation
Methods to reduce CO2 concentration in classrooms using hybird ventilation
16
21
5:00 5:38
5:28
5:18
5:08
6:00 6:28
6:18
6:08
5:58
5:48
7:00 7:08
6:58
6:48
6:38
8:00 7:58
7:48
7:38
7:28
7:18
9:00 8:38
8:28
8:18
8:08
10:00 9:18
9:08
8:58
8:48
11:00 10:08
9:58
9:48
9:38
9:28
12:00 10:48
10:38
10:28
10:18
13:00 11:38
11:28
11:18
11:08
10:58
14:00 12:18
12:08
11:58
11:48
15:00 12:58
12:48
12:38
12:28
16:00 13:38
13:28
13:18
13:08
17:00 14:08
13:58
13:48
C 24
22
200
5:00 5:08 5:18 5:28 5:38 5:48 5:58 6:08 6:18 6:28 6:38 6:48 6:58 7:08 7:18 7:28 7:38 7:48 7:58 8:08 8:18 8:28 8:38 8:48 8:58 9:08 9:18 9:28 9:38 9:48 9:58 10:08 10:18 10:28 10:38 10:48 10:58 11:08 11:18 11:28 11:38 11:48 11:58 12:08 12:18 12:28 12:38 12:48 12:58 13:08 13:18 13:28 13:38 13:48 13:58 14:08 14:18 14:28 14:38 14:48 14:58 15:08 15:18 15:28 15:38 15:48 15:58 16:08 16:18 16:28 16:38 16:48 16:58
Methodology
Analysis of measurement results + 154ppm in 10 min
6:00
+ 486ppm in 1H
Series1
7:00
Mean air temperature, Deg-C
Methods to reduce CO2 concentration in classrooms using hybird ventilation 8:00 9:00
-115 PPM in 10min
PPM ppm 1400
23
1200
23
1000
800
22
600
400
10:00 11:00 Series1
12:00 13:00 14:00 15:00 16:00 17:00
CO2, ppm (vol)
17
Methodology Building simulation Model total number of occupants : 40 measuring time and date : from 5:00AM to 5:00PM 10 oct 2019 CO2 level exceded the benchmark for 2H
CO2 in classroom 423.00 436.00 444.00 401.00 421.00 434.00 415.00 425.00 430.00 441.00 429.00 458.00 475.00 464.00 445.00 456.00 434.00 459.00 444.00 448.00 457.00 461.00 442.00 518.00 561.00 680.00 805.00 959.00 997.00 1004.00 1004.00 1104.00 1191.00 1270.00 1237.00 1230.00 1115.00 1143.00 1183.00 1189.00 1171.00 1040.00 971.00 938.00 871.00 852.00 834.00 805.00 861.00 891.00 925.00 946.00 975.00 917.00 908.00 929.00 913.00 867.00 910.00 877.00 943.00 883.00 886.00 889.00 889.00 876.00 877.00 904.00 925.00 898.00 883.00 871.00
CO2 in IDA ICE 400.44 400.44 400.45 400.45 400.46 400.46 400.46 400.46 400.46 400.46 400.46 404.62 404.62 404.62 413.44 413.44 429.09 453.72 495.08 543.8 607 683.57 780.07 901.15 901.15 974.63 1076.9 1142.8 1223.6 1262.4 1284.8 1289.2 1287.6 1271.6 1251.7 1216.4 1181 1124.1 1079.2 1029.3 953.96 896 863.65 826.93 822.86 838.02 889.49 919.9 987.6 1006.3 1024.8 1024.6 999.98 982.6 923.44 877.38 848.18 834.44 834.44 838.26 845.85 865.22 894.88 927.59 937.93 937.93 916.24 873.51 873.51 809.04 763.25 725.81
-22.56 -35.56 -43.55 -0.55 -20.54 -33.54 -14.54 -24.54 -29.54 -40.54 -28.54 -53.38 -70.38 -59.38 -31.56 -42.56 -4.91 -5.28 51.08 95.80 150.00 222.57 338.07 383.15 340.15 294.63 271.90 183.80 226.60 258.40 280.80 185.20 96.60 1.60 14.70 -13.60 66.00 -18.90 -103.80 -159.70 -217.04 -144.00 -107.35 -111.07 -48.14 -13.98 55.49 114.90 126.60 115.30 99.80 78.60 24.98 65.60 15.44 -51.62 -64.82 -32.56 -75.56 -38.74 -97.15 -17.78 8.88 38.59 48.93 61.93 39.24 -30.49 -51.49 -88.96 -119.75 -145.19
Calibration CO2 ,ppm
PPM
1400. 1200.00
1000 800.00
600.00
400 200.00
0.00
CO2 in classroom CO2 in ida ice Energy Consump�on 110
C
Air temperatures
22.4
100
22.2
90
22 80
21.8
70
21.6
60
21.4
50
21.2 6:00 AM
7:00 AM
8:00 AM
9:00 AM
10:00 AM
11:00 AM
12:00 PM
1:00 PM
2:00 PM
3:00 PM
4:00 PM
5:00 PM
Margin of Error = 5.46%
Methods to reduce CO2 concentration in classrooms using hybird ventilation
18
Scenario 1 Framework Double Clear Air (WIN7)1 dfsds Material
Without shading Solar heat gain coefficient (g) Solar transmittance (t) Visible transmittance U-value
0.557 0.455 0.711 2.814
Diffusion factor
0.0
Fraction of the total window area : 0.1
Frame
2
total number of occupants measuring time and date
U-valua=2.0(w/(m)
40 5:00AM to 5:00PM 7 oct 2019
window description Casement window : with fixed glass section at bottom , two seing - out sections at top ;crank -operted
Window schedule opening hours
5:00AM
6:00AM
7:00AM
8:00AM
9:00AM
10:00AM 11:00AM 12:00PM
1:00PM
2:00PM
3:00PM
4:00PM
5:00PM
work hours
The window opening hours were selected when the CO2 level reached above 1,000
Methods to reduce CO2 concentration in classrooms using hybird ventilation
19
Scenario 1 The level of carbon dioxide is still high above the 1000ppm
CO2 ,ppm
ppm 1200
1000
800
600
Opening 25%
400
Window schedule 200
opening hours
5:00AM
6:00AM
7:00AM
8:00AM
9:00AM
10:00AM 11:00AM 12:00PM
1:00PM
2:00PM
3:00PM
4:00PM
0
5:00PM
work hours
Air flows in zone
L/S 1000
5:00 AM 6:00AM 7:00AM 8:00AM 9:00AM 10:00AM 11:00AM 12:00PM 1:00PM 2:00PM 3:00PM 4:00PM 5:00PM
c
Energy Consump�on
300
Mean air temperature
30 29
800
250
28 27
600
200
26
400
25
150 24
200
23
100 0
5:00 AM
6:00AM
7:00AM
8:00AM
9:00AM
10:00AM 11:00AM 12:00PM
1:00PM
2:00PM
3:00PM
4:00PM
22
5:00PM
50 -200
5:00 AM 6:00AM
7:00AM
8:00AM
9:00AM 10:00AM 11:00AM 12:00PM 1:00PM
2:00PM
3:00PM
4:00PM
5:00PM
Methods to reduce CO2 concentration in classrooms using hybird ventilation
21
5:00 AM
6:00AM
7:00AM
8:00AM
9:00AM
10:00AM 11:00AM 12:00PM
1:00PM
2:00PM
3:00PM
4:00PM
5:00PM
20
Scenario 1 The level of carbon dioxide at 1,000 and the air temperature is close to 24.5
CO2 ,ppm
ppm 1200
1000
800
600
Opening 50%
400
Window schedule opening hours
5:00AM
6:00AM
7:00AM
8:00AM
9:00AM
10:00AM 11:00AM 12:00PM
200
1:00PM
2:00PM
3:00PM
4:00PM
0
5:00PM
work hours
1000
c
Energy Consump�on
Air flows in zone
L/S
5:00 AM 6:00AM 7:00AM 8:00AM 9:00AM 10:00AM 11:00AM 12:00PM 1:00PM 2:00PM 3:00PM 4:00PM 5:00PM
300
Mean air temperature
30 29
800
250
28 27
600
200
26
400
25
150 24
200
23
100 0
5:00 AM
6:00AM
7:00AM
8:00AM
9:00AM
10:00AM 11:00AM 12:00PM
1:00PM
2:00PM
3:00PM
4:00PM
22
5:00PM
50 -200
5:00 AM 6:00AM
7:00AM
8:00AM
9:00AM 10:00AM 11:00AM 12:00PM 1:00PM
2:00PM
3:00PM
4:00PM
Methods to reduce CO2 concentration in classrooms using hybird ventilation
5:00PM
21
5:00 AM
6:00AM
7:00AM
8:00AM
9:00AM
10:00AM 11:00AM 12:00PM
1:00PM
2:00PM
3:00PM
4:00PM
5:00PM
21
Scenario 1 The level of carbon dioxide decreased below 1000ppm and the temperature to 25
CO2 ,ppm
ppm 1200
1000
800
Opening
600
75%
400
Window schedule 200
5:00AM
6:00AM
7:00AM
8:00AM
9:00AM
10:00AM 11:00AM 12:00PM
1:00PM
2:00PM
3:00PM
4:00PM
5:00PM
0
5:00 AM 6:00AM 7:00AM 8:00AM 9:00AM 10:00AM 11:00AM 12:00PM 1:00PM 2:00PM 3:00PM 4:00PM 5:00PM
work hours
Air flows in zone
L/S 1000
c
Energy Consump�on
300
Mean air temperature
30 29
800
250
28
600
27
200 26 400
25
150
24
200
23
100 0
-200
5:00 AM
6:00AM
7:00AM
8:00AM
9:00AM
10:00AM 11:00AM 12:00PM
1:00PM
2:00PM
3:00PM
4:00PM
22
5:00PM
50
5:00 AM 6:00AM
7:00AM
8:00AM
9:00AM 10:00AM 11:00AM 12:00PM 1:00PM
2:00PM
3:00PM
4:00PM
5:00PM
Methods to reduce CO2 concentration in classrooms using hybird ventilation
21
5:00 AM
6:00AM
7:00AM
8:00AM
9:00AM
10:00AM 11:00AM 12:00PM
1:00PM
2:00PM
3:00PM
4:00PM
5:00PM
22
Scenario 1 The level of carbon dioxide decreased below 1000ppm and the temperature arise to 26
CO2 ,ppm
ppm 1200
1000
800
600
Opening 100%
400
Window schedule
5:00AM
6:00AM
7:00AM
8:00AM
9:00AM
10:00AM 11:00AM 12:00PM
1:00PM
200
2:00PM
3:00PM
4:00PM
5:00PM
0
5:00 AM 6:00AM 7:00AM 8:00AM 9:00AM 10:00AM 11:00AM 12:00PM 1:00PM 2:00PM 3:00PM 4:00PM 5:00PM
work hours
Air flows in zone
L/S 1000
c
Energy Consump�on
300
Mean air temperature
30 29
800
250
28 27
600
200 26 400
25
150
24
200
23
100 0
-200
5:00 AM
6:00AM
7:00AM
8:00AM
9:00AM
10:00AM 11:00AM 12:00PM
1:00PM
2:00PM
3:00PM
4:00PM
22
5:00PM
50
5:00 AM 6:00AM
7:00AM
8:00AM
9:00AM 10:00AM 11:00AM 12:00PM 1:00PM
2:00PM
3:00PM
4:00PM
Methods to reduce CO2 concentration in classrooms using hybird ventilation
5:00PM
21
5:00 AM
6:00AM
7:00AM
8:00AM
9:00AM
10:00AM 11:00AM 12:00PM
1:00PM
2:00PM
3:00PM
4:00PM
5:00PM
23
Scenario 2 Framework Double Clear Air (WIN7)1 dfsds Material
Without shading Solar heat gain coefficient (g) Solar transmittance (t) Visible transmittance U-value
0.557 0.455 0.711 2.814
Diffusion factor
Frame total number of occupants measuring time and date
0.0
Fraction of the total window area : 0.1 2
U-valua=2.0(w/(m)
40 5:00AM to 5:00PM 7 oct 2019
Window schedule
5:00AM
6:00AM
7:00AM
8:00AM
9:00AM
10:00AM 11:00AM 12:00PM
1:00PM
2:00PM
3:00PM
4:00PM
5:00PM
work hours
Methods to reduce CO2 concentration in classrooms using hybird ventilation
24
25%
50%
0.2
25%
0.2
0.2
0.1
50%
0.2
100%
75%
50%
0.1
100%
75%
50%
0.3
0.3
0.3
25%
0.4
100%
75%
0.3
25%
0.4
0.4
0.4
0.1
75%
Methods to reduce CO2 concentration in classrooms using hybird ventilation
0.1
100%
25
Scenario 2 0.1 0.2
0.3
0.4
CO2 , ppm (vol)
ppm
1200 1100 1000 900 800 700
25%
Opening
600
25%
500 400
Window schedule 5:00AM
6:00AM
7:00AM
8:00AM
9:00AM
10:00AM 11:00AM 12:00PM
1:00PM
0.1 2:00PM
3:00PM
4:00PM
0.2
0.3
0.4
5:00PM
work hours
energy consump�on
InďŹ&#x201A;ow through external walls, L/s
Mean air temperature, Deg-C
230
950
24
210
23.5
190
750
170
550
150
350
110
23 22.5
130
22
90
150
21.5
70 50
-50
0.1
0.2
0.3
0.4
21
0.1
0.2
0.3
0.4
Methods to reduce CO2 concentration in classrooms using hybird ventilation
0.1
0.2
0.3
0.4
26
Scenario 2 0.1 0.2
0.3
CO2 , ppm (vol)
0.4
ppm
1200 1100 1000 900 800 700
50%
Opening
600
50%
500 400
Window schedule 0.1 5:00AM
6:00AM
7:00AM
8:00AM
9:00AM
10:00AM 11:00AM 12:00PM
1:00PM
2:00PM
3:00PM
4:00PM
0.2
0.3
0.4
5:00PM
work hours
energy consump�on
InďŹ&#x201A;ow through external walls, L/s
Mean air temperature, Deg-C
230
950
24
210
23.5
190
750
170
23
150
550
22.5
130 350
110
22
90 150
21.5
70 50
-50
0.1
0.2
0.3
0.4
21
0.1
0.2
0.3
0.4
Methods to reduce CO2 concentration in classrooms using hybird ventilation
0.1
0.2
0.3
0.4
27
Scenario 2 0.1 0.2
0.3
0.4
CO2 , ppm (vol)
ppm
1200 1100 1000 900 800 700
75%
Opening
600
75%
500 400
Window schedule 0.1 5:00AM
6:00AM
7:00AM
8:00AM
9:00AM
10:00AM 11:00AM 12:00PM
1:00PM
2:00PM
3:00PM
4:00PM
0.2
0.3
0.4
5:00PM
work hours
InďŹ&#x201A;ow through external walls, L/s
Mean air temperature, Deg-C
energy consump�on 24
230
950
210
23.5
190
750
23
170 150
550
22.5
130
350
110
22
90
150
21.5
70 50
-50
0.1
0.2
0.3
0.4
21
0.1
0.2
0.3
0.4
Methods to reduce CO2 concentration in classrooms using hybird ventilation
0.1
0.2
0.3
0.4
28
Scenario 2 0.1 0.2
0.3
0.4
CO2 , ppm (vol)
ppm
1200 1100 1000 900 800 700
100%
Opening
600
100%
500 400
Window schedule 0.1 5:00AM
6:00AM
7:00AM
8:00AM
9:00AM
10:00AM 11:00AM 12:00PM
1:00PM
2:00PM
3:00PM
4:00PM
0.2
0.3
0.4
5:00PM
work hours
Mean air temperature, Deg-C
energy consump�on
InďŹ&#x201A;ow through external walls, L/s
24
230
950
210
23.5
190
750
23
170 150
550
22.5
130 350
22
110 90
150
21.5
70
21
50
-50
0.1
0.2
0.3
0.4
0.1
0.2
0.3
0.4
Methods to reduce CO2 concentration in classrooms using hybird ventilation
0.1
0.2
0.3
0.4
29
Scenario 2 The lowest rate of carbon dioxide was when the opening level 75% and the window depth were 0.4m and The highest rate of carbon dioxide was when the opening level 25% and the window depth were 0.1m The highest temperature when the opening level was 100 and the depth of the window 0.4m The lowest temperature when the opening level was 25 and the depth of the window 0.1m
Mean air temperature, Deg-C
+ CO 2
ppm 1000
24
23.5
900
23
800
22.5
700
22
600
21.5
500
21
5:00 AM
6:00AM
7:00AM
8:00AM
9:00AM
10:00AM
11:00AM
12:00PM
1:00PM
2:00PM
3:00PM
4:00PM
0.1+25
0.2+25
0.3+25
0.4+25
0.1+50
0.2+50
0.3+50
0.4+50
0.1+75
0.2+75
0.3+75
0.4+75
0.1+100
0.2+100
0.3+100
0.4+100
co2 0.1+ 25
0.2+25 co2
0.3 + 25 co2
0.4+25 co2
0.1+50 co2
0.2+50
0.3+50
0.4+50
0.1+75co2
0.2+75 co2
0.3+75 co2
0.4+75co2
0.1+100co2
0.2+50 co2
0.3+100 co2
0.4+100 co2
Methods to reduce CO2 concentration in classrooms using hybird ventilation
5:00PM
400
30
Scenario 2 The lowest rate of carbon dioxide was when the opening level 75% and the window depth were 0.4m and The highest rate of carbon dioxide was when the opening level 25% and the window depth were 0.1m The highest Energy consumption when the opening level was 100 and the depth of the window 0.4m The lowest Energy consumption when the opening level was 25 and the depth of the window 0.1m
energy consump�on + CO2 ppm 220
1000
200 900
180
800 160
140
700
120 600
100
500 80
60
5:00 AM
6:00AM
7:00AM
8:00AM
9:00AM
10:00AM
11:00AM
12:00PM
1:00PM
2:00PM
3:00PM
4:00PM
0.1+25
0.2+25
0.3+25
0.4+25
0.1+50
0.2+50
0.3+50
0.4+50
0.1+75
0.2+75
0.3+75
0.4+75
0.1+100
0.2+100
0.3+100
0.4+100
co2 0.1+ 25
0.2+25 co2
0.3 + 25 co2
0.4+25 co2
0.1+50 co2
0.2+50
0.3+50
0.4+50
0.1+75co2
0.2+75 co2
0.3+75 co2
0.4+75co2
0.1+100co2
0.2+50 co2
0.3+100 co2
0.4+100 co2
Methods to reduce CO2 concentration in classrooms using hybird ventilation
5:00PM
400
31
Scenario 2 The lowest rate of carbon dioxide was when the opening level 75% and the window depth were 0.4m
InďŹ&#x201A;ow , L/s + CO2
ppm 1000
950
and The highest rate of carbon dioxide was when the opening level 25% and the window depth were 0.1m The highest Inflow when the opening level was 100 and the depth of the window 0.4m The lowest Inflow when the opening level was 25 and the depth of the window 0.1m
900 750
800
550
700
350 600
150 500
-50
5:00 AM
6:00AM
7:00AM
8:00AM
9:00AM
10:00AM
11:00AM
12:00PM
1:00PM
2:00PM
3:00PM
4:00PM
0.1+25
0.2+25
0.3+25
0.4+25
0.1+50
0.2+50
0.3+50
0.4+50
0.1+75
0.2+75
0.3+75
0.4+75
0.1+100
0.2+100
0.3+100
0.4+100
co2 0.1+ 25
0.2+25 co2
0.3 + 25 co2
0.4+25 co2
0.1+50 co2
0.2+50
0.3+50
0.4+50
0.1+75co2
0.2+75 co2
0.3+75 co2
0.4+75co2
0.1+100co2
0.2+50 co2
0.3+100 co2
0.4+100 co2
Methods to reduce CO2 concentration in classrooms using hybird ventilation
5:00PM
400
32
Scenario 2 Inï¬&#x201A;ow , L/s + ST It is clear that there is an inverse relationship between air exchange and surface temperature
31 950 30
29
750
28
27
550
26
25
350
24
23
150
22
-50
5:00 AM
6:00AM
7:00AM
8:00AM
9:00AM
10:00AM
11:00AM
12:00PM
1:00PM
2:00PM
3:00PM
4:00PM
0.1+25
0.2+25
0.3+25
0.4+25
0.1+50
0.2+50
0.3+50
0.4+50
0.1+75
0.2+75
0.3+75
0.4+75
0.1+100
0.2+100
0.3+100
0.4+100
ST 0.1+ 25
0.2+ 0.25 ST
0.3 + 25 ST
0.4+25 ST
0.1+50 ST
0.2+50 ST
0.3+50 ST
0.4+50 ST
0.1+75 ST
0.2+75 ST
0.3+75 ST
0.4+75 ST
0.1+100 ST
0.2+50 ST
0.3+100 ST
0.4+100 ST
Methods to reduce CO2 concentration in classrooms using hybird ventilation
5:00PM
21
33
W1
W2
0.2
0.35 0.3
Air velocity
0.25 0.2 0.15 0.1 0.05 0
0
1
2
3
4
3
4
Point No. Normal window
Box window
Grid independent test 0.12
Air velocity
0.1 0.08 0.06 0.04 0.02 0
0
1
2
Measurment point No. Fine mesh
Methods to reduce CO2 concentration in classrooms using hybird ventilation
Medium mesh
Coarse mesh
34
Mean air temperature
c
humidity
% 90
23 22.8
85
22.6 22.4
80
22.2 22
75
21.8 21.6
70
21.4 21.2
65
21 20.8
5:00 AM 6:00AM 7:00AM 8:00AM 9:00AM 10:00AM 11:00AM 12:00PM 1:00PM 2:00PM 3:00PM 4:00PM Series1
60
5:00 AM
6:00AM
7:00AM
8:00AM
9:00AM
Series2
10:00AM Series1
11:00AM
12:00PM
1:00PM
2:00PM
3:00PM
4:00PM
Series2
c 33
W1
W2
L/S
Surface temperatures
Air flows in zone 31
900 800
29
700 600
27
500
+
25
400 300
23
200 100
21
0
0.2
-100 5:00 AM 6:00AM 7:00AM 8:00AM 9:00AM 10:00AM 11:00AM 12:00PM 1:00PM 2:00PM 3:00PM 4:00PM Series1
25%
Energy Consump�on
W1 W2
19
5:00 AM
6:00AM
7:00AM
8:00AM
9:00AM
Series2
200 180 160 140 120 100 80 60 40 20 0
10:00AM
Series1
11:00AM
12:00PM
1:00PM
2:00PM
3:00PM
2:00PM
3:00PM
4:00PM
Series2
CO2 ,ppm
ppm
1200
1000
800
600
400
200
0
Series1
Series2
Methods to reduce CO2 concentration in classrooms using hybird ventilation
5:00 AM
6:00AM
7:00AM
8:00AM
9:00AM
10:00AM 11:00AM 12:00PM Series1
1:00PM
4:00PM
Series2
35
humidity
Mean air temperature %
c
100
24.5
90
24
80
23.5
70
23
60
22.5
50
22 21.5
30
21
20
20.5
10
20
0 5:00 AM 6:00AM 7:00AM 8:00AM 9:00AM 10:00AM 11:00AM 12:00PM 1:00PM 2:00PM 3:00PM 4:00PM Series1
W1
W2
+ 0.2
L/S
30
500
25
400
20
300
15
200
10
100
5 5:00 AM 6:00AM 7:00AM 8:00AM 9:00AM 10:00AM 11:00AM 12:00PM 1:00PM 2:00PM 3:00PM 4:00PM
0
5:00 AM 6:00AM 7:00AM 8:00AM 9:00AM 10:00AM 11:00AM 12:00PM 1:00PM 2:00PM 3:00PM 4:00PM
Series2
Energy Consump�on
W2
c
600
Series1
Series2
Surface temperatures
Air flows in zone
35
50% W1
Series1
700
0
5:00 AM 6:00AM 7:00AM 8:00AM 9:00AM 10:00AM 11:00AM 12:00PM 1:00PM 2:00PM 3:00PM 4:00PM
Series2
Series1
Surface temperatures ppm
250
1000
Series2
Surface temperatures CO 2 ,ppm Surface temperatures Surface Surfacetemperatures temperatures
900
200
800 700
150
600 500
100
400 300
50
200 100
0
5:00 AM 6:00AM 7:00AM 8:00AM 9:00AM 10:00AM 11:00AM 12:00PM 1:00PM 2:00PM 3:00PM 4:00PM Series1
Series2
Methods to reduce CO2 concentration in classrooms using hybird ventilation
0
5:00 AM 6:00AM 7:00AM 8:00AM 9:00AM 10:00AM 11:00AM 12:00PM 1:00PM 2:00PM 3:00PM 4:00PM Series1
Series2
36
Mean air temperature
c 26
90
25
80 70
24
60
23
50
22
40
21
30 20
20
10
19
L/S
700
30
800
20 15
300
10
200
5
100
0.2
0
5:00 AM 6:00AM 7:00AM 8:00AM 9:00AM 10:00AM 11:00AM 12:00PM 1:00PM 2:00PM 3:00PM 4:00PM
Series2
Series1
Series2
CO2 ,ppm 250
W2
5:00 AM 6:00AM 7:00AM 8:00AM 9:00AM 10:00AM 11:00AM 12:00PM 1:00PM 2:00PM 3:00PM 4:00PM Series1
75%
Surface temperatures
25
400
0
Series2
35
500
W1
Series1
c
600
+
5:00 AM 6:00AM 7:00AM 8:00AM 9:00AM 10:00AM 11:00AM 12:00PM 1:00PM 2:00PM 3:00PM 4:00PM
21.96 21.89 21.88 22 22.54 23.35 24.45 25.15 23.63 22.05 22.03 21.94
Air flows in zone
W2
0
5:00 AM 6:00AM 7:00AM 8:00AM 9:00AM 10:00AM 11:00AM 12:00PM 1:00PM 2:00PM 3:00PM 4:00PM Series1
W1
humidity
%
100
Energy Consump�on
ppm
1000 900
200
800
150
600
700 500 400
100
300 200
50 0
100 0
5:00 AM 6:00AM 7:00AM 8:00AM 9:00AM 10:00AM 11:00AM 12:00PM 1:00PM 2:00PM 3:00PM 4:00PM Series1
Series2
Methods to reduce CO2 concentration in classrooms using hybird ventilation
5:00 AM 6:00AM 7:00AM 8:00AM 9:00AM 10:00AM 11:00AM 12:00PM 1:00PM 2:00PM 3:00PM 4:00PM Series1
Series2
37
c
Mean air temperature
27
95
26
90
25
85
24
80
23
75
22
70 %
21
65
20
60
L/S
W1
W2
Air flows in zone
Surface temperatures
31
860
30
760
29
660
28 27 26
460
25
360
24
260
0.2
c
960
560
+
humidity
%
23
160
22
60
21
100% Energy Consump�on
W1 W2
ppm
270
1000
220
900
170
CO2 ,ppm
800 700
120 600 70 20
Methods to reduce CO2 concentration in classrooms using hybird ventilation
500 400
38
Recommendations By scheduling existing windows, ventilation can be improved in the classroom without significantly affecting thermal comfort in moderate climatic conditions. Improving the air quality in the current classroom is a very important requirement for raising the educational competence of students and ensuring the health of users The hybird ventilation system has proven to be effective and can be an important tool for improving air quality in educational spaces Existing windows can be changed to windows suggested in the search
It is best not to increase the number of students within the classroom until it is ensured that the quality of the space is not affected
Methods to reduce CO2 concentration in classrooms using hybird ventilation
39
Conclusion
This research focused on finding a solution to find ways to improve the quality of indoor air for educational classes through hybrid ventilation systems. As the research has shown us, hybrid methods for ventilation are a suitable solution and can be applied through existing windows or by developing better windows. These same methods can be used on other areas with a different climate Different from the one in which the study was held, as the research showed that increasing the number of students within the educational space may affect the quality of the educational space, which causes a decrease in the level of educational achievement and an increase in the level of health risk for students
Methods to reduce CO2 concentration in classrooms using hybird ventilation
40