scholarly journals Predicting the Air Quality, Thermal Comfort and Draught Risk for a Virtual Classroom with Desk-Type Personalized Ventilation Systems

Buildings ◽  
2018 ◽  
Vol 8 (2) ◽  
pp. 35 ◽  
Author(s):  
Eusébio Conceição ◽  
Cristina Santiago ◽  
Mª. Lúcio ◽  
Hazim Awbi
Keyword(s):  
Air Quality ◽  
Thermal Comfort ◽  
Virtual Classroom ◽  
Personalized Ventilation ◽  
Ventilation Systems

scholarly journals Operation Testing of an Advanced Personalized Ventilation System

Energies ◽  
2019 ◽  
Vol 12 (9) ◽  
pp. 1596 ◽  
Author(s):  
Csáky ◽  
Kalmár ◽  
Kalmár
Keyword(s):  
Air Quality ◽  
Thermal Comfort ◽  
Indoor Air Quality ◽  
Indoor Air ◽  
Distribution System ◽  
Noise Level ◽  
Background Noise ◽  
Ventilation System ◽  
Air Distribution ◽  
Personalized Ventilation

Using personalized ventilation systems in office buildings, important energy saving might be obtained, which may improve the indoor air quality and thermal comfort sensation of occupants at the same time. In this paper, the operation testing results of an advanced personalized ventilation system are presented. Eleven different air terminal devices were analyzed. Based on the obtained air velocities and turbulence intensities, one was chosen to perform thermal comfort experiments with subjects. It was shown that, in the case of elevated indoor temperatures, the thermal comfort sensation can be improved considerably. A series of measurements were carried out in order to determine the background noise level and the noise generated by the personalized ventilation system. It was shown that further developments of the air distribution system are needed.

scholarly journals Evaluation of Effects of the Humidity Level-Based Auto-Controlled Centralized Exhaust Ventilation Systems on Thermal Comfort of Multi-Family Residential Buildings in South Korea

2019 ◽  
Vol 11 (17) ◽  
pp. 4791
Author(s):  
Kwag ◽  
Park ◽  
Kim ◽  
Kim
Keyword(s):  
Air Quality ◽  
South Korea ◽  
Thermal Comfort ◽  
Indoor Air Quality ◽  
Indoor Air ◽  
Residential Buildings ◽  
Humidity Level ◽  
Exhaust Ventilation ◽  
Air Tightness ◽  
Ventilation Systems

Building air-tightness has been increased to make energy efficient buildings. However, various indoor air quality issues can be caused by high building air-tightness because it allows low air and moisture transmission through building envelop. In order to solve and prevent these issues, mechanical ventilation systems can be used to control the indoor humidity level. The purpose of this paper is to evaluate the performances of the Relative Humidity (RH)-sensor based auto-controlled centralized exhaust ventilation systems to manage indoor air quality and thermal comfort of multi-family residential buildings in South Korea. A series of field tests were performed for different target zones and for various moisture source scenarios. As a result, it was found that the auto-controlled centralized exhaust ventilation systems were able to control indoor air quality and to maintain the zones thermal comfort faster than the baseline cases that did not operate exhaust vents. The results presented in this paper can show the potential and the feasibility of the auto-controlled centralized exhaust ventilation systems for multi-family residential buildings in South Korea. It is expected that the results presented in this paper would be useful for building owners, engineers, and architects when designing building systems.

scholarly journals Sistema de Ventilação Personalizada Instalado na Poltrona em Cabine de Aeronave: Análise da Concentração e da Eficiência na Remoção de Partículas Expiratórias

REVISTA PLURI ◽  
2020 ◽  
Vol 1 (3) ◽  
pp. 77
Author(s):  
Victor Barbosa Felix ◽  
Douglas Fabichack Jr. ◽  
Paulo Rogério Celline ◽  
Arlindo Tribess
Keyword(s):  
Air Quality ◽  
Removal Efficiency ◽  
Experimental Analysis ◽  
Ventilation System ◽  
Particle Removal ◽  
Pv System ◽  
Aircraft Cabins ◽  
Personalized Ventilation ◽  
Mode Of Transport ◽  
Ventilation Systems

As pessoas viajam cada vez mais de avião e, muitas vezes, estas viagens são longas. A qualidade do ar dentro desse meio de transporte torna-se então uma questão crucial, principalmente agora que o mundo está passando por uma pandemia causada pela COVID 19. Uma forma de melhorar a qualidade do ar e as condições de conforto térmico dentro de uma cabine de aeronave está na utilização de novos sistemas de ventilação personalizada. No presente trabalho é apresentada análise experimental da influência de um sistema de ventilação personalizada (PV) na concentração e na eficiência de remoção de partículas expiratórias em cabine de aeronave com sistema de ventilação convencional por mistura (MV). Os ensaios foram realizados em um mock-up com 12 lugares, com três fileiras de quatro poltronas. Medições de concentração de partículas foram realizadas na região de respiração, a 1,10m do piso, em todos os assentos da cabine. Os resultados mostram que a eficiência na remoção de partículas na região de respiração, considerando toda a cabine, é de até 25% para partículas de 5 a 10 μm e de até 30% para partículas de 2 a 5μm. Os resultados mostram também que a eficiência na remoção de partículas é praticamente igual para o sistema PV operando tanto no assento da janela quanto no assento do corredor para todos os tamanhos de partículas. Os resultados da eficiência de remoção de partículas mostram que o sistema PV influencia significativamente a remoção de partículas no assento no qual o sistema está operando e na cabine como um todo.Palavras-chave: Sistemas de Ventilação, Qualidade do Ar, Partículas Expiratórias, Análise Experimental, Cabines de AeronavesAbstractPeople travel more and more by plane, and often these trips are long. Air quality within this mode of transport then becomes a crucial issue, especially now that the world is experiencing a pandemic caused by COVID 19. A way to improve air quality and thermal comfort conditions inside a cabin of aircraft is in the use of new personalized ventilation systems. This work presents an experimental analysis of the influence of a personalized ventilation system (PV) on the concentration and efficiency of removal of expiratory particles in an aircraft cabin with a conventional mixing ventilation system (MV). The tests were carried out in a mock-up with 12 seats, three rows with four abreast. Measurements of particle concentration were performed in the breathing region, 1.10 m from the floor, in all seats of the cabin. The results show that the efficiency in removing particles in the breathing region, considering the entire cabin, is up to 25% for particles of 5 to 10 μm and up to 30% for particles of 2 to 5 μm. The results also show that particle removal efficiency is practically the same for the PV system operating on both the window seat and the aisle seat for all particle sizes. The results of particle removal efficiency show that the PV system significantly influences the removal of particles in the seat on which the system is perating and in the cab as a whole.Keyworks: Ventilation systems, Air Quality, Expiratory droplets, Experimental analysis, Aircraft cabins

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

2019 ◽  
Vol 29 (4) ◽  
pp. 527-542 ◽  
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.

Numerical study of different ceiling-mounted air distribution systems for a virtual classroom environment

2016 ◽  
Vol 26 (10) ◽  
pp. 1382-1396 ◽  
Author(s):  
Eusébio Z. E. Conceição ◽  
Cristina I. M. Santiago ◽  
Hazim B. Awbi
Keyword(s):  
Air Quality ◽  
Thermal Comfort ◽  
Air Temperature ◽  
Distribution Systems ◽  
Numerical Study ◽  
Virtual Classroom ◽  
Comfort Level ◽  
Air Distribution ◽  
Air Supply ◽  
Distribution Index

This paper presents a comparative numerical study of different ceiling-mounted-localized air distribution systems placed above students in a virtual classroom in summer conditions. The influence of four different ceiling-mounted-localized air distribution systems, using vertical descendent jets, on the thermal comfort, local thermal discomfort, and air quality levels was numerically evaluated. The air distribution index, developed previously, was used for non-uniform environment. This index considers the thermal comfort level, air quality level, effectiveness for heat removal, and effectiveness for contaminant removal. Numerical simulations were conducted for a virtual classroom equipped with one of four different ceiling-mounted-localized air distribution systems and with 6 desks, 6 or 12 students, and 2 upper airflow outlets. Inlet air supply temperature of 20 and 24℃ and an outdoor air temperature of 28℃ were used. The simulation results show that the air supply system having a vertical air jet placed at 1.8 m above the floor level (Case III), and with an inlet area of 0.01 m2 and a supply air velocity of 3 m/s would represent the best option in comparison with other air supply methods. In general, the air distribution index value decreases with an increase in inlet air temperature and the number of occupants. The air distribution index values are highest for Case III representing a classroom with 6 or 12 occupants with an inlet air temperature of 20 or 24℃.

scholarly journals Evaluation of Integral Effect of Thermal Comfort, Air Quality and Draught Risk for Desks Equipped with Personalized Ventilation Systems

Energies ◽  
2021 ◽  
Vol 14 (11) ◽  
pp. 3235
Author(s):  
Eusébio Conceição ◽  
Hazim Awbi
Keyword(s):  
Air Quality ◽  
Thermal Comfort ◽  
Numerical Study ◽  
Heat Removal ◽  
Thermal Conditions ◽  
Air Distribution ◽  
Pv Systems ◽  
Integral Effect ◽  
Personalized Ventilation ◽  
Air Removal

This work evaluates the integral effect of thermal comfort (TC), indoor air quality (IAQ) and Draught Risk (DR) for desks with four personalized ventilation (PV) systems. The numerical study, for winter and summer thermal conditions, considers a virtual chamber, a desk, four different PV systems, four seats and four virtual manikins. Two different PV configurations, two upper and two lower air terminal devices (ATD) with different distance between them are considered. In this study a coupling of numerical methodology, using one differential and two integral models, is used. The heating, ventilating and air conditioning (HVAC) system performance in this work is evaluated using DR and room air removal effectiveness (εDR) that is incorporated in an Air Distribution Index (ADI). This new index, named the Air Distribution Turbulence Index (ADTI), is used to consider simultaneously the TC, the IAQ, the DR and the effectiveness for heat removal (εTC), contaminant removal (εAQ) and room air removal (εDR). The results show that the ADI and ADTI, are generally higher for Case II than for Case I, increase when the inlet air velocity increases, are higher when the exit air is located at a height 1.2 m than when is located at 1.8 m, and are higher for summer conditions than for winter conditions. However, the values are higher for the ADI than ADTI.

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