Photocatalytic oxidation (PCO) is an innovative method of removing volatile organic compounds (VO... more Photocatalytic oxidation (PCO) is an innovative method of removing volatile organic compounds (VOCs) from indoor air. PCO technology employs a semiconductor (such as TiO2) and ultraviolet light to decompose VOCs via successive oxidation processes and creates CO2 and H2O as the ultimate products of complete mineralization. The greatest drawback of this technology is, however, the production of hazardous by-products. The possible health risk posed by hazardous by-products inhibits the commercial adoption of PCO-based air purifiers in the indoor environment. Modeling is a powerful tool to address the chemical interaction and mass transfer phenomenon in the PCO reactor. This study presents the modeling of a ternary mixture of VOCs and generated by-products using a proposed degradation reaction pathway. A one-dimensional mathematical model by considering the axially dispersed plug flow and Langmuir-Hinshelwood (L-H) based reaction rate as well as linear source spherical emission model (L...
The Vapor Compression Refrigeration System (VCRS) is one of the most critical systems in building... more The Vapor Compression Refrigeration System (VCRS) is one of the most critical systems in buildings typically used in Heating, Ventilation, and Air Conditioning (HVAC) systems in residential and industrial sections. Therefore, identifying their faults and evaluating their reliability are essential to ensure the required operations and performance in these systems. Various components and subsystems are included in the VCRS, which need to be analyzed for system reliability. This research’s objective is conducting a comprehensive system reliability analysis on the VCRS by focusing on fault identification and determining the fault impacts on these systems. A typical VCRS in an office building is selected for this research regarding this objective. The corresponding reliability data, including the probability distributions and parameters, are collected from references to perform the reliability evaluation on the components and subsystems of the VCRS. Then the optimum distribution paramete...
Abstract Non-isothermal stratification conditions can alter the airflow pattern and pollutant dis... more Abstract Non-isothermal stratification conditions can alter the airflow pattern and pollutant dispersion process within urban areas. The present study is focused on the impact of various stratification conditions, namely, stable, isothermal (neutral), and unstable, on the airflow and concentration fields around an isolated high-rise building. Zonal Reynolds-averaged Navier-Stokes (RANS)-large eddy simulation (LES), also known as embedded large eddy simulation (ELES), is employed for simulating the airflow and concentration fields under non-isothermal boundary layers in order to make a balance between computational costs and accuracy. Comparing the results predicted by the present ELES with an available LES study, with almost similar computational settings (i.e., the inflow turbulence generation method, grid resolution, etc.) shows better performance of ELES in predicting the concentration field. The findings also illustrate that the impact of the unstable stratification condition on turbulence statistics is more pronounced than that of the stable stratification condition. The present article also investigates the effect of thermal stratification conditions on the mechanisms of pollutant dispersion, namely, convective and turbulent diffusion fluxes. The findings reveal that an increase in turbulence kinetic energy (TKE), caused by the unstable thermal stratification condition, increases the concentration fluctuations, which causes the pollutant concentration to be decreased. Furthermore, spectral and proper orthogonal decomposition (POD) analyses are performed for all stratification scenarios. The results show that by altering the thermal condition from isothermal to non-isothermal, either stable or unstable conditions, the contribution of the primary dominant modes to total TKE increases.
PurposeOne of the most critical infrastructures is a data center (DC) because of it having many s... more PurposeOne of the most critical infrastructures is a data center (DC) because of it having many servers, computers and other equipment. DCs provide online services for various companies in the information technology (IT) industry. DC facilities should provide reliable online services while addressing the required quality and performance level considering maximum reliability and availability. The purpose of this study is to represent and classify the main findings in this area and to identify the main research gaps and shortcomings from the perspective of research.Design/methodology/approachThis paper provides an organized and systematic literature review focusing on topics regarding the operation and maintenance (O&M) management of DCs.FindingsAlthough there are several studies on O&M management systems for industrial systems and facilities, a limited number of studies with few methods and models have focused on DCs so far and these facilities require more attention. This paper iden...
IOP Conference Series: Materials Science and Engineering, 2019
Window operation plays a vital role in indoor environmental quality (IEQ) and building energy con... more Window operation plays a vital role in indoor environmental quality (IEQ) and building energy consumption while maintaining occupants’ expected IEQ levels. In recent years, the influencing factors of window opening/closing behaviour have been widely investigated and evaluated in residential buildings, aiming at simulating building energy performance in a realistic manner. However, due to the challenges in collecting and analysing occupancy-related data, previous research works emphasized more on indoor/outdoor parameters (e.g. temperature and CO2). Hence, the correlation between occupancy patterns with window behaviour in a household has not been well explored. The aim of this study is to analyse the patterns of window opening and closing behaviour in French households and identify respective driving factors. The analysis was based on the data collected from four apartments in a high-performance residential building located in Lyon, France. The dataset considered in this study inclu...
Photocatalytic oxidation (PCO) is an innovative method of removing volatile organic compounds (VO... more Photocatalytic oxidation (PCO) is an innovative method of removing volatile organic compounds (VOCs) from indoor air. PCO technology employs a semiconductor (such as TiO2) and ultraviolet light to decompose VOCs via successive oxidation processes and creates CO2 and H2O as the ultimate products of complete mineralization. The greatest drawback of this technology is, however, the production of hazardous by-products. The possible health risk posed by hazardous by-products inhibits the commercial adoption of PCO-based air purifiers in the indoor environment. Modeling is a powerful tool to address the chemical interaction and mass transfer phenomenon in the PCO reactor. This study presents the modeling of a ternary mixture of VOCs and generated by-products using a proposed degradation reaction pathway. A one-dimensional mathematical model by considering the axially dispersed plug flow and Langmuir-Hinshelwood (L-H) based reaction rate as well as linear source spherical emission model (L...
The Vapor Compression Refrigeration System (VCRS) is one of the most critical systems in building... more The Vapor Compression Refrigeration System (VCRS) is one of the most critical systems in buildings typically used in Heating, Ventilation, and Air Conditioning (HVAC) systems in residential and industrial sections. Therefore, identifying their faults and evaluating their reliability are essential to ensure the required operations and performance in these systems. Various components and subsystems are included in the VCRS, which need to be analyzed for system reliability. This research’s objective is conducting a comprehensive system reliability analysis on the VCRS by focusing on fault identification and determining the fault impacts on these systems. A typical VCRS in an office building is selected for this research regarding this objective. The corresponding reliability data, including the probability distributions and parameters, are collected from references to perform the reliability evaluation on the components and subsystems of the VCRS. Then the optimum distribution paramete...
Abstract Non-isothermal stratification conditions can alter the airflow pattern and pollutant dis... more Abstract Non-isothermal stratification conditions can alter the airflow pattern and pollutant dispersion process within urban areas. The present study is focused on the impact of various stratification conditions, namely, stable, isothermal (neutral), and unstable, on the airflow and concentration fields around an isolated high-rise building. Zonal Reynolds-averaged Navier-Stokes (RANS)-large eddy simulation (LES), also known as embedded large eddy simulation (ELES), is employed for simulating the airflow and concentration fields under non-isothermal boundary layers in order to make a balance between computational costs and accuracy. Comparing the results predicted by the present ELES with an available LES study, with almost similar computational settings (i.e., the inflow turbulence generation method, grid resolution, etc.) shows better performance of ELES in predicting the concentration field. The findings also illustrate that the impact of the unstable stratification condition on turbulence statistics is more pronounced than that of the stable stratification condition. The present article also investigates the effect of thermal stratification conditions on the mechanisms of pollutant dispersion, namely, convective and turbulent diffusion fluxes. The findings reveal that an increase in turbulence kinetic energy (TKE), caused by the unstable thermal stratification condition, increases the concentration fluctuations, which causes the pollutant concentration to be decreased. Furthermore, spectral and proper orthogonal decomposition (POD) analyses are performed for all stratification scenarios. The results show that by altering the thermal condition from isothermal to non-isothermal, either stable or unstable conditions, the contribution of the primary dominant modes to total TKE increases.
PurposeOne of the most critical infrastructures is a data center (DC) because of it having many s... more PurposeOne of the most critical infrastructures is a data center (DC) because of it having many servers, computers and other equipment. DCs provide online services for various companies in the information technology (IT) industry. DC facilities should provide reliable online services while addressing the required quality and performance level considering maximum reliability and availability. The purpose of this study is to represent and classify the main findings in this area and to identify the main research gaps and shortcomings from the perspective of research.Design/methodology/approachThis paper provides an organized and systematic literature review focusing on topics regarding the operation and maintenance (O&M) management of DCs.FindingsAlthough there are several studies on O&M management systems for industrial systems and facilities, a limited number of studies with few methods and models have focused on DCs so far and these facilities require more attention. This paper iden...
IOP Conference Series: Materials Science and Engineering, 2019
Window operation plays a vital role in indoor environmental quality (IEQ) and building energy con... more Window operation plays a vital role in indoor environmental quality (IEQ) and building energy consumption while maintaining occupants’ expected IEQ levels. In recent years, the influencing factors of window opening/closing behaviour have been widely investigated and evaluated in residential buildings, aiming at simulating building energy performance in a realistic manner. However, due to the challenges in collecting and analysing occupancy-related data, previous research works emphasized more on indoor/outdoor parameters (e.g. temperature and CO2). Hence, the correlation between occupancy patterns with window behaviour in a household has not been well explored. The aim of this study is to analyse the patterns of window opening and closing behaviour in French households and identify respective driving factors. The analysis was based on the data collected from four apartments in a high-performance residential building located in Lyon, France. The dataset considered in this study inclu...
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