Incorporating cooling and ventilation effects into a single IEQ indicator

The influence of dissimilar cooling and ventilation system combinations on indoor environmental quality (IEQ) has been studied. A comparison of chilled ceiling cooling in combination with displacement ventilation, cooling with fan coil unit, and cooling with flat wall displacement inlets was performed. All observed variations were evaluated based on whole-body and local thermal comfort criteria as well as with regard to ventilation effectiveness. The analysis was made based on results of numerical simulations carried out in two steps. First, DesignBuilder was applied to model the buildings’ thermal performance and to evaluate its interaction with the environment. The latter included the calculation of heat gains as well as the heat loss on the boundary surfaces of the observed air-conditioned room. In the second step, ANSYS Fluent was used to simulate the response of indoor environment by utilizing the simulation results obtained in the first step, in order to evaluate the interaction between building and human. Afterwards, the observed thermal comfort and ventilation criteria were merged into a novel indoor environment indicator, which enables to describe the indoor environment quality with a single value. Among the analysed systems, the ceiling cooling system in combination with displacement ventilation was found to be the most suitable as it offers a high level of thermal comfort with adequate ventilation efficiency. Fan coil cooling was the least favourable option in terms of thermal comfort, while flat wall displacement inlets exhibited the lowest ventilation effectiveness. The performed investigation demonstrated the necessity to assess indoor environment with regard to IEQ in addition to energy consumption.

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FIELD STUDY ON THE THERMAL COMFORT AND VENTILATION EFFECTIVENESS IN A CONCERT HALL WITH DISPLACEMENT VENTILATION SYSTEM

Journal of Architecture and Planning (Transactions of AIJ) ◽

10.3130/aija.67.37_6 ◽

2002 ◽

Vol 67 (559) ◽

pp. 37-44

Author(s):

Sueng-jae LEE ◽

Shin-ichi TANABE ◽

Ken-ichi KIMURA ◽

Kazuhiro OTAKA ◽

Makoto KOYAMA ◽

...

Keyword(s):

Thermal Comfort ◽

Field Study ◽

Ventilation System ◽

Displacement Ventilation ◽

Concert Hall ◽

Ventilation Effectiveness

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Computational Modeling of Particulate Pollutant Transport in a Ventilated Room in the Presence of Two Heated Breathing and Rotating Manikins

Volume 1C, Symposia: Gas-Liquid Two-Phase Flows; Gas and Liquid-Solid Two-Phase Flows; Numerical Methods for Multiphase Flow; Turbulent Flows: Issues and Perspectives; Flow Applications in Aerospace; Fluid Power; Bio-Inspired Fluid Mechanics; Flow Manipulation and Active Control; Fundamental Issues and Perspectives in Fluid Mechanics; Transport Phenomena in Energy Conversion From Clean and Sustainable Resources; Transport Phenomena in Materials Processing and Manufacturing Processes ◽

10.1115/fedsm2017-69102 ◽

2017 ◽

Author(s):

Seyed Ali Keshavarz ◽

Mazyar Salmanzadeh ◽

Goodarz Ahmadi

Keyword(s):

Air Quality ◽

Computational Modeling ◽

Indoor Air Quality ◽

Indoor Air ◽

Rotational Motion ◽

Indoor Environment ◽

Ventilation System ◽

Thermal Plume ◽

Displacement Ventilation ◽

Simulation Results

Recently, attention has been given to indoor air quality due to its serious health concerns. Clearly the dispersion of pollutant is directly affected by the airflow patterns. The airflow in indoor environment is the results of a combination of several factors. In the present study, the effects of thermal plume and respiration on the indoor air quality in a ventilated cubicle were investigated using an unsteady computational modeling approach. The person-to-person contaminant transports in a ventilated room with mixing and displacement ventilation systems were studied. The effects of rotational motion of the heated manikins were also analyzed. Simulation results showed that in the cases which rotational motion was included, the human thermal plume and associated particle transport were significantly distorted. The distortion was more noticeable for the displacement ventilation system. Also it was found that the displacement ventilation system lowered the risk of person-to-person transmission in an office space in comparison with the mixing ventilation system. On the other hand the mixing system was shown to be more effective compared to the displacement ventilation in removing the particles and pollutant that entered the room through the inlet air diffuser.

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Thermal comfort investigation of stratified indoor environment in displacement ventilation: Climate-adaptive building with smart windows

Sustainable Cities and Society ◽

10.1016/j.scs.2018.11.029 ◽

2019 ◽

Vol 46 ◽

pp. 101354 ◽

Cited By ~ 10

Author(s):

Khalesi Javad ◽

Goudarzi Navid

Keyword(s):

Thermal Comfort ◽

Indoor Environment ◽

Displacement Ventilation ◽

Smart Windows

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Human response to the thermal indoor environment created by a radiant, and a combined radiant and convective cooling system

E3S Web of Conferences ◽

10.1051/e3sconf/201911102060 ◽

2019 ◽

Vol 111 ◽

pp. 02060

Author(s):

Ongun B. Kazanci ◽

Dolaana Khovalyg ◽

Takayoshi Iida ◽

Yoshitaka Uno ◽

Tomo-oki Ukiana ◽

...

Keyword(s):

Human Subject ◽

Indoor Environment ◽

Cooling System ◽

Human Subjects ◽

Whole Body ◽

Indoor Environments ◽

Climate Chamber ◽

Convective Cooling ◽

Physical Measurements ◽

Two Systems

This study reports the main findings from a series of human subject experiments, where the subjects were exposed to the different indoor environments created by different cooling systems. The studied systems were a radiant cooling system (chilled ceiling and mixing ventilation, CCMV), and a combined radiant and convective cooling system (radiant diffuse ceiling ventilation, RDCV). The experiments were conducted in a climate chamber under controlled conditions. The climate chamber was configured as a two-person office room. 24 human subjects (12 female and 12 male) were chosen. The exposure lasted three hours and the participants were allowed to work on their own tasks (normal office work) during the exposure. The cooling load was 54 W/m2 and the room temperature at a reference location was kept constant at 26°C (summer conditions). The results show that under both systems, whole body thermal sensation was between slightly warm and neutral (closer to neutral with the RDCV system), and the overall thermal acceptability was almost the same for both systems (close to clearly acceptable). The satisfaction of the human subjects with the thermal environment was very close under the two systems; between satisfactory and slightly satisfactory (closer to satisfactory). Air movement acceptability (slightly higher and closer to clearly acceptable with the RDCV system) was also very close with the two systems. The results of the human subject experiments agree well with the physical measurements of the thermal indoor environment and confirm that the studied systems created very similar thermal indoor environments.

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Using CFD simulations to develop an upward airflow displacement ventilation system for manure-belt layer houses to improve the indoor environment

Biosystems Engineering ◽

10.1016/j.biosystemseng.2018.08.006 ◽

2019 ◽

Vol 178 ◽

pp. 294-308 ◽

Cited By ~ 5

Author(s):

Xinjie Tong ◽

Se-Woon Hong ◽

Lingying Zhao

Keyword(s):

Indoor Environment ◽

Ventilation System ◽

Displacement Ventilation ◽

Cfd Simulations

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Assessing the indoor thermal comfort of a toll station

MATEC Web of Conferences ◽

10.1051/matecconf/201928202031 ◽

2019 ◽

Vol 282 ◽

pp. 02031

Author(s):

Ricardo M.S.F. Almeida ◽

Eva Barreira ◽

Sandra Soares ◽

Ramos Nuno M.M. ◽

Sérgio Lopes ◽

...

Keyword(s):

Thermal Comfort ◽

Indoor Environment ◽

Thermal Sensation ◽

Physical Parameters ◽

Indoor Environmental Quality ◽

Thermal Perception ◽

Health And Wellbeing ◽

Local Thermal Comfort ◽

Toll Station ◽

Global And Local

The importance of a good indoor environment for peoples’ health and wellbeing is nowadays clearly established. Besides enhancing the wellbeing of building occupants and helping decrease the occurrence of building related illness, a good indoor environment can also lead to a decrease in worker complaints and absenteeism. This paper presents the results of a three-month monitoring campaign where the thermal comfort of a toll station was evaluated, including the main room and the cabins. The physical parameters required for the assessment of both global and local thermal comfort were measured and the results were compared with the thermal perception of the occupants, which was collected through questionnaires. The indoor environmental quality in the main room was better than in the cabins and a mismatch between the PMV index and the occupants thermal sensation was identified.

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A comparison of the thermal comfort performances of a radiation floor cooling system when combined with a range of ventilation systems

Indoor and Built Environment ◽

10.1177/1420326x19869412 ◽

2019 ◽

Vol 29 (4) ◽

pp. 527-542 ◽

Cited By ~ 2

Author(s):

Jiying Liu ◽

Zhuangzhuang Li ◽

Moon Keun Kim ◽

Shengwei Zhu ◽

Linhua Zhang ◽

...

Keyword(s):

Thermal Comfort ◽

Cooling System ◽

Whole Body ◽

Equivalent Temperature ◽

Thermal Discomfort ◽

Computational Fluid Dynamics Simulations ◽

Radiant Floor Cooling System ◽

Personalized Ventilation ◽

Dynamics Simulations ◽

Ventilation Systems

This study conducted a series of computational fluid dynamics simulations to evaluate the thermal comfort performance of a radiant floor cooling system when combined with different ventilation systems, including mixed ventilation (MV), stratum ventilation (SV), displacement ventilation (DV) and ductless personalized ventilation (DPV). A window temperature of 32°C and three different floor temperatures including 20, 22 and 24°C were set in summer. We used the vertical air temperature differences (VATD) at ankle and head level, the percentage of dissatisfied, the draught rate at the ankle level and the equivalent temperature as our main evaluation indices. Our results show that the VATD in DV system can reach up to about 5°C, compared with about 2°C in MV and SV systems. For the DPV system, there is only a marginal drop in the VATD. For the DV and DPV cases, with a rate of air changes per hour (ACH) of 2.4−1, we recorded a higher draught rate at the ankle level, ranging from 6.55% to 9.99%. The lower equivalent temperature values for the foot and calf segments occur when the floor temperature is 20°C. In all cases, the equivalent temperature values of the whole body indicate an acceptable level of thermal discomfort.

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Modeling the Thermal Comfort of Internal Building Spaces in School

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.584-586.761 ◽

2014 ◽

Vol 584-586 ◽

pp. 761-764 ◽

Cited By ~ 5

Author(s):

Andrey Volkov ◽

Artem Sedov ◽

Pavel Chelyshkov ◽

Ekaterina Kulikova

Keyword(s):

Thermal Comfort ◽

Indoor Environment ◽

Critical Factor ◽

Thermal Conditions ◽

Strong Relationship ◽

Indoor Environmental Quality ◽

Highly Sensitive ◽

Materials Used ◽

Crucial Part

<p class="p0">Creating a comfortable indoor environment has been one of the mainconcerns when it comes to the design and operation of buildings. Buildings are a crucial part of our daily life, on average people spends 85 % of their time performing activities inside of buildings and therefore the quality of the indoor environment is a critical factor affecting the happiness and productivity of building users.The indoor environmental quality has a strong relationship on the thermal conditions of a space which is directly affected by the amount of heat lost or gained due to the properties of the materials used, the external environmental conditions and the inner sources of heat; In consequence, efforts have to be made to maintain proper thermal conditions by means of using natural and mechanical strategies to provide heating, cooling and ventilation. While the thermal comfort is an important aspect for the average user of a building, it becomes a critical aspect when it comes to population highly sensitive to thermal conditions.</p>

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Reducing Energy Demand in Commercial Buildings: Balancing Convection and Radiant Cooling

ASME 2010 4th International Conference on Energy Sustainability, Volume 1 ◽

10.1115/es2010-90370 ◽

2010 ◽

Author(s):

Lee Chusak ◽

Andrew Harris ◽

Ramesh Agarwal

Keyword(s):

Thermal Comfort ◽

Energy Demand ◽

Energy Savings ◽

Ventilation System ◽

Computational Domain ◽

Exterior Wall ◽

Displacement Ventilation ◽

Comfort Levels ◽

Isothermal Wall ◽

Chilled Ceiling

Using Computational Fluid Dynamics (CFD) software, three different cooling systems used in contemporary office environments are modeled to compare energy consumption and thermal comfort levels. Incorporating convection and radiation technologies, full-scale models of an office room compare arrangements for (a) an all-air overhead system (mixing ventilation), (b) an all-air raised floor system (displacement ventilation), and (c) a combined air and hydronic radiant system (displacement ventilation with a chilled ceiling). The computational domain for each model consists of one isothermal wall (simulating an exterior wall of the room) and adiabatic conditions for the remaining walls, floor, and ceiling (simulating interior walls of the room). Two sets of computations were conducted. The first set of computations utilized a constant temperature isothermal exterior wall, while the second set utilized an isothermal wall that changed temperatures as a function of time simulating the temperature changes on the exterior wall of a building throughout a 24 hour period. Results show superior thermal comfort levels as well as substantial energy savings can be accrued using the displacement ventilation, especially the displacement ventilation with a chilled ceiling over the conventional mixing ventilation system.

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