Numerical simulation of the influence of external urban environmental conditions in the building windows performance

2020 ◽  
pp. 112-123
Author(s):  
Eusébio Conceiçã ◽  
João Gomes ◽  
Maria Manuela Lúcio ◽  
Maria Inês Conceição ◽  
Hazim Awbi
Keyword(s):  
Air Quality ◽  
Thermal Comfort ◽  
Indoor Air Quality ◽  
Indoor Air ◽  
Environmental Conditions ◽  
Numerical Study ◽  
Carbon Dioxide Concentration ◽  
System Control ◽  
Hvac System ◽  
Indoor Thermal Comfort

This paper presents a numerical study of the influence of external urban environmental conditions, namely, the solar radiation, in the building windows performance. A software that simulates the building thermal behaviour with complex topology, in transient conditions, is developed and used in the study of indoor air quality and indoor thermal comfort of the occupants of a building, under typical summer conditions. As management strategy was implemented a control system to the Heating, Ventilation and Air Conditioning (HVAC) using the PMV (Predicted Mean Vote) index as controllable variable. The studied university building is located in a Mediterranean-type climate in the south of Portugal. The indoor thermal comfort, evaluated by the PMV index, and the indoor air quality, evaluated by the carbon dioxide concentration, were obtained for all occupied spaces. In order to evaluate the implemented control strategy a set of results was obtained for the situations with and without HVAC system control. To exemplify the results obtained, two large compartments were chosen, one with windows facing South and the other without windows. As main conclusion, it can be stated that the use of the HVAC system controllable by the PMV index allows acceptable levels of thermal comfort within the category C of the ISO 7730 standard, and acceptable levels of indoor air quality within the limit proposed by the ASHRAE 62.1 standard.

Evaluation of comfort levels in office space equipped with HVAC system based in personalized ventilation system using energy produced in DSF systems

2020 ◽  
pp. 65-74
Author(s):  
Eusébio Conceição ◽  
Mª Inês Conceição ◽  
Mª Manuela Lúcio ◽  
João Gomes ◽  
Hazim Awbi
Keyword(s):  
Air Quality ◽  
Numerical Model ◽  
Thermal Comfort ◽  
Indoor Air Quality ◽  
Indoor Air ◽  
Numerical Study ◽  
Ventilation System ◽  
Airflow Rate ◽  
Hvac System ◽  
Personalized Ventilation

In this study the numerical simulation of a Heating, Ventilating and Air Conditioning (HVAC) system, based in a personalized ventilation system, installed in an occupied office desk is made. The energy is produced in a Dual Skin Facades (DSF) system installed in the outdoor environment. The personalized ventilation system, placed above and below the writing area, installed in the desk central area. The office desk is occupied by eight virtual manikins. The numerical simulation is made in a winter typical day. This numerical study considers a coupling of a differential numerical model and an integral numerical model. The differential numerical model simulates the Computational Fluids Dynamics (CFD), evaluates the air velocity, air temperature, turbulence intensity and carbon dioxide concentration and calculates the indoor air quality. The integral numerical model simulates the Multi-Node Human Thermo-physiology Model, evaluates the tissue, blood and clothing temperatures distribution and calculates the thermal comfort level. The HVAC system, based on a DSF system, is built using three DSF unities, is equipped with internal venetian blinds. Each one, installed in a virtual chamber, is turned to south. The personalized ventilation system, made with eight upper and eight lower air terminal devices, is installed in the desk central area. On each table top two upper and two lower air terminal devices are considered in the left and right manikin area, while on each side of the table two upper and two lower air terminal devices are placed between the manikins. The office desk is occupied by eight virtual manikins, one sitting on each table top and three sitting on each side of the meeting table. In this numerical study, carried out in winter conditions, the occupants’ clothing level is 1 clo. In these situations a typical activity level of 1.2 met is considered. The evolution of indoor environmental conditions, in the DSF and in the office room, are calculated during a full winter typical day. The thermal comfort, the indoor air quality, the effectiveness for heat removal, the effectiveness for contaminant removal and the Air Distribution Index (ADI), are evaluated. In accordance with the obtained results the thermal comfort levels increase when the air renovation rate increases and the indoor air quality level increases when the air renovation rate increases. However, the ADI is quite constant when the inlet airflow rate increases, because the thermal comfort number decreases when the inlet airflow rate increases and the air quality number increases when the inlet airflow rate increases.

scholarly journals Energy Production in Solar Collectors in a University Building Used to Improve the Internal Thermal Conditions in Winter Conditions

2021 ◽  
Vol 246 ◽  
pp. 03005
Author(s):  
Eusébio Conceição ◽  
João Gomes ◽  
Mª Manuela Lúcio ◽  
Hazim Awbi
Keyword(s):  
Air Quality ◽  
Thermal Comfort ◽  
Indoor Air Quality ◽  
Indoor Air ◽  
Energy Production ◽  
Numerical Study ◽  
Thermal Conditions ◽  
Solar Collectors ◽  
Transient Conditions ◽  
Winter Conditions

In this numerical study the energy production in solar collectors in a University building used to improve the internal thermal conditions is made. Passive and active solutions, using external solar collector and internal thermo-convectors, are used. The numerical simulation, in transient conditions, is done for a winter typical day with clean sky. This numerical study was carried out using a software that simulates the Building Dynamic Response with complex topology in transient conditions. The software evaluates the human thermal comfort and indoor air quality levels that the occupants are subjected, Heated Ventilation and Air Conditioned energy consumption, indoor thermal variables and other parameters. The university building has 107 compartments and is located in a Mediterranean-type environment. External solar water collectors, placed above the building’s roof, and internal thermo-convectors of water/air type, using mixing ventilation, are used as passive and active strategies, respectively. The thermal comfort level, using the Predicted Mean Vote index, and the indoor air quality, using the carbon dioxide concentration, are evaluated. The results show that in winter conditions the solar collectors improve the thermal comfort conditions of the occupants. The indoor air quality, in all ventilated spaces, is also guaranteed.

Analysis of Thermal Comfort and Air Quality in the Kindergarten Hart - A Case Study of a Unique Sustainable Building Design

2019 ◽  
Vol 887 ◽  
pp. 500-507
Author(s):  
Matthias Schuss ◽  
Mahnameh Taheri ◽  
Ulrich Pont ◽  
Ardeshir Mahdavi
Keyword(s):  
Air Quality ◽  
Thermal Comfort ◽  
Indoor Air Quality ◽  
Indoor Air ◽  
Environmental Conditions ◽  
Natural Ventilation ◽  
Building Design ◽  
Present Contribution ◽  
Ongoing Research ◽  
Indoor And Outdoor

The present contribution, reports on the results of ongoing research efforts on performance assessment of a number of buildings designed by the Austrian architect, Konrad Frey. He is a pioneer of energy-efficient architecture, and his designs, those dating back to the 1970s, adapted the principles of modern solar houses. The current study focuses on the Kindergarten Hart, which was especially designed focusing on the availability of cross ventilation option in building. For the purpose of analyzing thermal comfort, indoor air quality, and the occupants’ adaptive actions with respect to natural ventilation, we conducted long-term monitoring under summer and winter conditions. The monitoring efforts covered indoor and outdoor environmental conditions, as well as the state of windows. Thereby, study of the monitored dataset provides a better understanding of the building performance. Moreover, it makes it possible to examine whether the architect’s expectations in terms of thermal comfort and indoor air quality levels are fulfilled or not. In addition, investigation of the occupants’ interactions with windows, together with indoor and outdoor environmental conditions, assists understanding of possible associations between the window opening/closing and environmental parameters, as well as potential optimization of the control-oriented actions.

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.

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%.

scholarly journals Analysis of thermal comfort in education building in surveys

2018 ◽  
Vol 44 ◽  
pp. 00189 ◽  
Author(s):  
Agata Witkowska ◽  
Katarzyna Gładyszewska-Fiedoruk
Keyword(s):  
Air Quality ◽  
Thermal Comfort ◽  
Indoor Air Quality ◽  
Indoor Air ◽  
Noise Level ◽  
Ability To Work ◽  
Temperature Sensation ◽  
Indoor Thermal Comfort ◽  
University Of Technology ◽  
North Eastern

Main parameters of indoor air quality could influence people health and ability to work and ability to learning. The research was conducted in University of Technology building located in Białystok, north-eastern Poland. Research - surveys was devoted to issues related to the thermal comfort in a classroom of university. Interviewees declared perceptible temperature and described their feelings connected to the temperature sensation. Other indoor parameters were also analysed such as: temperature, humidity and indoor air quality and noise level. Peoples – students filled the surveys about thermal comfort and indoor parameters. The research included indoor thermal comfort.

scholarly journals Production of thermal energy in University building greenhouses in cold climate conditions

2021 ◽  
Vol 246 ◽  
pp. 03004
Author(s):  
Eusébio Conceição ◽  
João Gomes ◽  
Maria Manuela Lúcio ◽  
Hazim Awbi
Keyword(s):  
Air Quality ◽  
Thermal Comfort ◽  
Indoor Air Quality ◽  
Thermal Energy ◽  
Indoor Air ◽  
Numerical Study ◽  
Cold Climate ◽  
International Standards ◽  
Climate Conditions ◽  
Heated Air

The present work focuses on the production of thermal energy in University building greenhouses in cold climate conditions. The building model uses a system of energy and mass balance integral equations, which are solved by the Runge–Kutta–Felberg method with error control. This numerical study is about the thermal behaviour of a university building with complex topology, in winter and transient conditions. The thermal comfort of the occupants, using the Predicted Mean Vote index, and the indoor air quality, using the carbon dioxide concentration, are evaluated. This building has 319 compartments distributed by four floors and it is equipped with one internal greenhouse in the third floor. This greenhouse is located on the south facing facade and the heated air in this space will be transported to compartments located on the north facing façade. The spaces subject to the influence of the heated air coming from the greenhouse improve the level of thermal comfort of its occupants. The level of indoor air quality in occupied spaces is acceptable according to international standards.

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