Assessing the performance of the airflow window for ventilation and thermal comfort in office rooms (original) (raw)
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Proceedings Article, 2021
With the increment in time spent indoors, the contingence between building occupants and indoor air pollution has been lengthened. Accordingly, indoor air quality became a significant factor since the poor conditions can influence the occupants’ health and efficiency. Indoor air quality is mainly concerned with physical and thermophysical factors in conditioned environments and is related to occupants’ satisfaction levels on a variety of variables such as fresh air adequacy, air temperature, odor, humidity, and air velocity. This paper aims to investigate natural ventilation occupant-control methods to improve indoor air quality and increase building energy efficiency considering clean air intake levels and indoor air temperature levels. For this, variables related to climatic conditions, ventilation systems, and occupant’s control on window opening were investigated to provide healthy and liveable conditions. To comply with these goals, in an open-plan office building, the levels o...
Analysis of Thermal Comfort in an Office Space Using Two Typical Ventilation Modes
European Journal of Engineering Research and Science
This study carried out a comparative study to evaluate the air-conditioning performance of an office space under two typical ventilation modes (displacement and mixing ventilation system). A wall supply diffuser is located at the ceiling height for the mixing ventilation case, whereas, the supply diffuser is at the floor level for the displacement ventilation case. In both cases, the exhaust grill is located at the ceiling. From the result of the simulation, the researchers observed that the displacement ventilation system could have a higher risk of discomfort relating to vertical temperature gradient than when compared to the mixing ventilation case. More so, the simulation result indicates that the temperature distribution in an office building is a function of the type of ventilation system adopted and marginally affected by the diffuser arrangement.
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MATEC web of conferences, 2018
The paper presents the results of study into the air parameters in open space offices. As office workers spend about 1/3 of the day in such spaces, it is important to provide them with the right climate comfort, and that is determined, most importantly, by: the temperature and humidity of the air, quality of the air, and the concentration of CO2. Two objects of study were selected-both of them open space facilities, each with a different intensity of use. In the course of study, measurements were taken on the basis of which the distributions of temperature, humidity, and concentrations of CO2 in the entire volume of the space were determined. Also the empirical coefficients of CO2 emission by the office workers were marked out, dependent on the volume of the working area and the number of people using it. The coefficients were developed at optimal working parameters of fans in the ventilation system; the criterion for optimization being heat loss in the office caused by discharge of the used heated air into the atmosphere. The results of the study have also shown that the use of personal ventilation (PV) with an installed recuperator for heat recovery from the used air discharged from the room significantly improves the energy efficiency of an open space office building.
Experimental Investigation of Ventilation Performance in a Mock-Up Open-Plan Office
The COPE study was designed to investigate the effect of open-plan office design on the indoor environment, and on the occupant satisfaction with that environment. One task of this study is to examine the effect of office design on indoor air quality, ventilation and thermal comfort conditions. As the air diffuser layout is rarely changed, some changes in office design, such as the size and number of workstations and the partition height, may have adverse effects on indoor air quality and ventilation. It is therefore necessary to determine the effects of such design options on the ventilation performance and the indoor air quality conditions within and around individual workstations of open-plan offices. Le projet PRAO a été conçu pour étudier l'effet de la conception des bureaux à aire ouverte sur l'environnement intérieur et sur la satisfaction des occupants vis-à-vis de cet environnement. L'un des objectifs particuliers de l'étude consistait à examiner l'effet...
PERFORMANCE ANALYSIS OF VENTILATION
2018
The study focused on the ventilation effectiveness of buildings. The lecture hall in the mechanical engineering department of Olabisi onabanjo university, College of engineering, Ibogun campus, Ifo, Ogun state which has the biggest space to accommodate students were used as the study area. Ventilation is actually a combination of processes that results in the supply and removal of air in and from a building. The quality of indoor air may deteriorate when one or more of these processes is inadequate. For example, carbon dioxide (a gas that is produced when people breathe), may accumulate in building spaces if sufficient amounts of outdoor air are not brought into and distributed throughout the building. Carbon dioxide is a surrogate for indoor pollutants that may cause occupants to grow drowsy, get headaches, or function at lower activity levels. Therefore, increasing the rate at which outdoor air is supplied to the building decreases indoor air problems. The data such as temperature, co2 concentration and air flow velocity were measured, the instrument used for the measurement of the various temperature zones is the digital peak meter which has an accuracy of ± 0.5oC and 0.5% for temperature readings. A TIM10 CO2 meter was also used to measure the concentration of CO2 in the hall in PPM. Two significant ventilation parameters were used to assess the effectiveness of ventilation. One is the ventilation effectiveness ratio for heat distribution (Et), and the other parameter is the ventilation effectiveness ratio for contaminant removal (EC). The ventilation effectiveness results show that the air is not well mixed (moving from supply to exhaust without fully mixing in the occupied zone) in the lecture hall, these results when the supply air by passes the occupants without fully settling in the breathing zone. The ventilation effectiveness with perfect mixing is 100% Ev is 1. According to Ashrae 62-2001, the air that bypasses the occupants without fully mixing has a low value of 0.5. The minimum ventilation rate of 15 & 15.5 cfm per person shows that the ventilation rate required for acceptable indoor air quality is met according to Ashrae standard 62-1989 of the minimum requirement for Indoor Air Quality which is 15 cfm & 8 l/s per person.
Energy and Buildings, 2013
The effect of low ventilation rates (1 or 0.5 air change per hour) on thermal comfort and ventilation effectiveness was experimentally studied in a simulated residential room equipped with radiant floor heating/cooling and mixing ventilation systems. The tests were performed for various positions of supply and extract air terminals and different winter and summer boundary conditions. Vertical air temperature, operative temperature and air velocity profiles were measured in different positions in the room, and equivalent temperatures were derived, in order to characterize thermal comfort.
International Journal of Integrated Engineering
Refer to the Malaysian Standard code of practice on Energy Efficiency and Use of Renewable Energy for Nonresidential Building (MS1525:2007), it was stated in the guideline for natural ventilation as said; "Natural ventilation is the use of fresh air of sufficient volume and air change to ventilate enclosed spaces without active temperature controls or mechanical means. Fresh air is required in buildings to alleviate odours and improved indoor environmental quality. Provisions for naturally ventilated lobby areas, corridors, lift cores, staircases should be encouraged. This could aid compliance with the requirements from the fire authorities for smoke venting of the spaces in the event of the fire. In some of these cases, spill air from adjacent spaces is sufficient for air change to ventilate the space and provide thermal comfort with reducing energy. Natural ventilation strategies rely on the movement of air through space to equalise pressure. One of its purposes is to encourage the design, construction, operation, and maintenance of new and existing buildings in a manner that reduces the use of energy without constraining creativity in design, building function and the comfort and the occupants, and appropriately dealing with cost consideration (MS1525, 2007). 2. Literature Review Ventilation has defined as the exchange of air [1]. To create a comfortable environment inside the office building, there is a need to provide good ventilation. Without the exchange of air, both the temperature and the humidity of room will increase above the outdoor value, due to the heat and moisture output of human bodies and of the various human Abstract: Natural ventilation is one of the criteria of passive design strategies to reduce the usage of active ventilation especially an airconditioning system which will involve a hugeamount of operation cost. The aim of this study was to identify and analyse the criteria of natural ventilation in the selected office buildings. The analysis had been made based on the architectural and passive design component provided in MS 1525:2007 for the office building. This case study is important in helping to understand the relationship between natural ventilation, energy efficiency and cost effectiveness.
A Performance-Based Window Design and Evaluation Model for Naturally Ventilated Offices
Buildings
This study proposes a performance-based window design model for optimised natural ventilation potential by reducing the level of indoor carbon dioxide (CO2) concentration and improving thermal comfort, consequently minimising supplementary heating/cooling loads. The model consists of several stages: (1) Knowledge acquisition, (2) establishing a relationship between window design and natural ventilation, (3) identifying performance criteria and the design of experiments (DOE), (4) conducting performance-based dynamic simulations, (5) evaluation of findings, and (6) making informed design decisions. The study also proposed an evaluation method by which assessments of indoor CO2 concentration and adaptive thermal comfort are performed using the threshold suggested by the World Health Organisation (WHO, Geneva, Switzerland) and the acceptability categories of the British/European standard BS EN 15251:2007. The proposed model was applied to a single office inspired by the staff offices a...
Sustainability, 2020
Natural ventilation through window openings is an inexpensive and effective solution to bring fresh air into internal spaces and improve indoor environmental conditions. This study attempts to address the "indoor air quality-thermal comfort" dilemma of naturally ventilated office buildings in the Mediterranean climate through the effective use of early window design. An experimental method of computational modelling and simulation was applied. The assessments of indoor carbon dioxide (CO 2) concentration and adaptive thermal comfort were performed using the British/European standard BS EN 15251:2007. The results indicate that when windows were opened, the first-floor zones were subjected to the highest CO 2 levels, especially the north-facing window in the winter and the south-facing window in the summer. For a fully glazed wall, a 10% window opening could provide all the office hours inside category I of CO 2 concentration. Such an achievement requires full and quarter window openings in the cases of 10% and 25% window-to-floor ratios (WFR), respectively. The findings of the European adaptive comfort showed that less than 50% of office hours appeared in category III with cross-ventilation. The concluding remarks and recommendations are presented.
Ventilation characteristics of an air-conditioned office building in Singapore
Building and Environment, 2002
The primary functions of mechanical ventilation systems include the delivery of outdoor air to the occupants, the removal of indoor contaminants and the maintenance of thermal comfort conditions in the occupied zones. Air exchange e ectiveness can be employed to characterise the ventilation air mixing within a room. This paper presents our ÿndings pertaining to air exchange effectiveness values in a seven-storey o ce building. Tracer gas analysis, based on concentration decay method, is employed to determine these values. The results indicate air ow patterns in the occupied zones which approximate "perfect mixing". The measured concentration levels of indoor air pollutants are also found to be within reasonable limits.