As global warming worsens, most resident behaviors tend to increase the use of air conditioners for better thermal comfort without considering other indoor air quality factors such as CO2 and pollution levels. This research aims to develop a cost-effective ventilator system that relies on the environmental parameter to control its speed to improve indoor air quality and reduce energy consumption, while maintaining occupant thermal satisfaction according to both ASHRAE 55 and EN 16798 standards. Of samples (using Arduino serial monitor) 75 Figure 3.15: CO2 concentration in ppm vs. number of samples 75.
Thermal equilibrium after 30 minutes of preheating 78 Figure 3.19: (a) Hall effect (B) and magnetic flux density with respect to the air gap.
General Introduction 21
Therefore, IAQ is closely related to thermal comfort and a balance between them is required to achieve an acceptable indoor environmental quality shown in Figure 1.1 (Cheng et al., 2014). Indoor human comfort depends on four factors, which are indoor air quality, thermal comfort, visual comfort and acoustic comfort (called Quite in Figure 1.1). Despite the publication of indoor air quality guidelines, existing air quality parameters differ widely from WHO standard values; therefore, researchers and engineers have proposed the introduction of real-time air quality monitoring systems to decode and analyze human behavior and environmental factors to improve indoor air quality accordingly.
Data collected from real-time IAQ monitoring systems is used to ensure effective ventilation methods.
Importance of the Study 23
As shown in Figure 1.2, APF (Annual Performance Factor), which represents the heating and cooling capacity per kWh during one year of air conditioner use. APF is proportional to energy efficiency, so the higher the APF, the higher the energy efficiency of the air conditioner. The number of volunteers “n” was categorized into two main groups namely air conditioner owners and non-air conditioner owners.
The total number of volunteers was 243, of which approximately 60% (148 volunteers) of them owned air conditioners that consumed annual energy of almost 28 GJ/year, while owners of non-air conditioners consumed only 20 GJ/year, which is 30% less ( Kubota et al., 2011).
Problem Statement 26
Another 2001 study by De Dear called "The adaptive model of thermal comfort and energy conservation in the built environment". 250 samples were collected and plotted using Excel to show a clearer graph as shown in Figure 3.15. The placement of the Hall effect sensor relative to the wind turbine has been adjusted to achieve Slide-By sensing as shown in Figure 3.20.
The maximum rating before reaching the zero point is the point farthest from the magnet, which means it is the distance to complete one turn. This gave an approximate peak airflow of 1.6898 m/s (≈ 1.7 m/s), the same approach was used to calculate the airflow at different fan speed levels. The fan was compared to a previous study published by the IES (The institution of engineers) in Sri Lanka (Attalage and Sugathapala, 2001), where the performance of different pedestal fans was analyzed at a distance of 80 cm between the fan and the measurement point. (named as X) as shown in Figure 3.30.
The module used was a MicroSD card module with an SPI (Serial Peripheral Interface) interface driver as shown in Figure 3.36. The replica of the room and the apartment used in the testing were designed as shown in Figure 3.47 to Figure 3.49 for a better optimal experience. The research also plotted the relationship between the duty cycle and both speed and voltage as shown in Figure 3.55.
Aims and Objective 29
Scope and Limitation of the Study 30
Indoor Air Quality (IAQ) 32
Indoor air quality is defined by the American Occupational Safety and Health Administration as a description of indoor air condition in terms of many environmental factors, such as temperature, humidity, airflow rate (air ventilation), and levels of pollutants. Indoor air quality has become more discussed recently as many researchers have linked poor IAQ to multiple chronic diseases due to inhalation and exposure to many pollutants and particulate matter (PM 2.5) (Chan et al., 2016 ), while other research has linked poor indoor air quality to a range of irritants and carcinogenic effects (Spengler and Sexton, 1983). In 2015, the United States Environmental Protection Agency announced that indoor air quality had long been neglected, resulting in indoor air pollution levels 2 to 5 times worse than outdoors (US EPA, 2015).
Nevertheless, this research paper will primarily focus on improving indoor air factors that can be improved with proper air circulation (temperature, humidity, air flow, CO2 and CO levels) (Schulze et al., 2017).
Brief History on Indoor Air Quality Awareness and
The air conditioning function involves taking the air from the room to heat and cool it and then recycling the air back to the room (Shah, 2009). The invention of the air conditioner led to a reduction in air quality, as it is accompanied by many disadvantages, such as the increase in CO2 levels along with other gaseous pollutants such as CO, SO2, NOX, O3, radon and VOCs. Based on the above disadvantages, the air conditioner cannot replace a ventilation system, although many may assume it.
To avoid sick building syndrome, the WHO has listed the procedures that must be achieved to maintain a good IQA, for example by undergoing air conditioner maintenance every six months and carrying out an audit every two years to ensure that indoor air quality is acceptable is and meets the specifications.
Factors of Thermal Comfort 37
Therefore, a balance must be achieved between fans, air conditioners and natural ventilation to provide thermal comfort and a good IQA for people in all environments. These factors are used to calculate the predicted mean vote (PMV), which is one of the most popular thermal comfort models as shown in Figure 2.2. The PMV model is widely used and validated by the American Professional Association for Heating, Ventilation, Air Conditioning and Refrigeration (ASHRAE) and the European standard for indoor environmental parameters (EN-16798), including it as a method to indicate and calculated thermal comfort in buildings (Ihtsham et al., 2015).
The study relied on the thermal comfort level based on the PMV model (Wafi et al., 2011).
Research Conducted to Build Thermal Control and Improve IAQ
So it can be shown on Figure 3.25 to Figure 3.29 that the rotation of the wind turbine increases when the speed increases within the same period. The research setup was also used by placing the standing fan at a distance of less than 1 m (about 75 cm, making it similar to the previous research where the distance was measured to be almost 80 cm) away from the desk, while the wind detection unit was placed. on the desk (used desk height is 77 cm) as shown in figure 3.31. After the coding was completed, the application successfully displayed the data collected by the microcontroller on a digital device (Android and IOS mobile phone) via Bluetooth connection as shown in Figure 3.42.
Testing Results 112
Case Study 1: Open Door Vs Closed Door Testing 112
Testing included two reference points; the first reference point represented the weather conditions prior to the activation of the ceiling fan, while the second reference point represented the weather conditions prior to the activation of the standing fan to aid in before/after comparisons. All tests were started at speed level 1, either using a ceiling fan or a standing fan. From Table 4.1 it can be seen that there are two reference points, the first is the weather conditions before the activation of the ceiling fan and the second is the activation of the upcoming fan.
Other data includes fan speed, temperature, humidity, CO2, CO and wind speed, as well as PMV and sensation, which are shown together with the reference point for comparison in two different diagrams, one representing the ceiling fan and the other represents the standing fan as shown in Figure 4.5. The result also that the temperature and humidity while using the standing fan were recorded to be less than the temperature and humidity level when using the ceiling fan, making the standing fan a better option in terms of thermal comfort. In terms of indoor air quality, the ceiling fan was chosen as a better option as the CO2 level was recorded at a higher level when using the standing fan than the ceiling fan.
In contrast, the CO level does not vary much between the standing fan and ceiling fan conditions, making the CO2 level the primary concern for indoor air quality and occupant health. Therefore, the standing fan can be categorized as a better option for thermal comfort, but increases the concentration of carbon dioxide, while the ceiling fan can achieve a better state of thermal comfort without degrading indoor air quality, however , another week of testing was conducted to support the findings of the first week. The results obtained from week 2 are similar to week 1, showing that the temperature level is significantly reduced when using a standing fan than when using a ceiling fan.
The results also showed that the CO2 level increases significantly when using a pedestal fan, as opposed to the ceiling fan, where the CO2 level changes are quite acceptable. Previous research also showed that the standing fan has more disadvantages than advantages during a heat wave, which explains why the CO2 content increased so strongly at a temperature of 32°C.
The Benchmark Results for the Developed Energy Efficient
The research also emphasized that further research should be done on the disadvantages of electric standing fans, as limited data was found (Eyy and GuptaS, 2017). Therefore, the ceiling fan was selected as the most suitable for use in the temperature- and humidity-based fan system for indoor environmental quality improvement as it provides both thermal comfort and indoor air quality. The case condition 9 and 10 are listed to ensure that indoor air quality is achieved by maintaining the CO2 level below 800 ppm and CO level below 8.7 ppm according to Table 2-4.
Sensors are therefore connected to the fan motor to ensure that the speed level of the fan will change according to the benchmark setting and guarantee both indoor air quality satisfaction and thermal comfort at all times.
The Energy Efficiency Analysis 127
Duty Cycle 20% Simulation 134
Duty Cycle 40% Simulation 135
Duty Cycle 60% Simulation 135
Based on the research conducted, the effectiveness of humidity and temperature based fan systems in terms of delivering indoor air quality without causing thermal discomfort was analyzed through three different case studies. The first case study included an inspection of indoor air quality and thermal comfort during opening/closing of doors, while the second and third case studies focused on monitoring indoor air quality and thermal comfort at different fan speed levels using two different fan types during the two previous weeks. In addition to an energy consumption of 25%, the maximum speed level required to achieve the IAQ and thermal comfort is level 3, which means that only a maximum PWM duty cycle of 60% is required, so the fan will not operate at full capacity resulting in the added benefit in terms of energy consumption and fan life.
By assuming mean radiant temperature equal to air temperature during PMV-based thermal comfort survey in air-conditioned buildings. Available at: https://www.semanticscholar.org/paper/Indoor-Air-Quality-and- Health-Cincinelli-Martellini/ce0bf30c1d9dc9948fc158c3ebf5d1d7964a9ab8 [Accessed: 3 March 2020]. ScienceDirect Thermal comfort analysis of PMV model Prediction in air-conditioned and naturally ventilated buildings.
Indoor air quality and thermal comfort - Results of a pilot study in retirement homes in Portugal. A comprehensive thermal comfort analysis of the cooling effect of the standing fan using questionnaires and a thermal manikin. Optimization of indoor air quality and thermal comfort in classrooms by developing an automatic window opening and closing system.
Review of Research on Air Conditioning and Indoor Air Quality Control for Human Health. An intelligent wireless sensor and control system to improve indoor air quality: monitoring, prediction and preaction.
