Assessment of thermal comfort in high-occupancy spaces with relevance to air distribution schemes: A case study of mosques

In high-occupancy intermittently operated buildings such as mosques and auditoriums, maintaining an acceptable thermal environment may present a challenging task. Variations in the operation and the thermal loads can result in variable and non-uniform thermal comfort conditions when the HVAC system is not properly designed. Non-uniformity of the thermal environment is greatly influenced by the design and scheme of the air distribution system. Mosques, with their distinctive five intermittent short occupancies and the non-fixed posture of occupants, present a unique case for investigation. In this study, the effect of air distribution of various schemes of a ceiling-based system on the thermal comfort in mosques is investigated. Air diffusion performance index and Fanger’s PMV method are used to assess thermal comfort. Three air distribution schemes at four diffuser terminal velocities were studied using the EnergyPlus and computational fluid dynamics techniques. Results indicate major variations in air diffusion performance index with each air distribution scheme type and diffuser terminal velocity. The uniformity of the PMV was entirely dependent on the air diffusion performance index value and exhibited large variations when the air diffusion performance index value was low. In most cases, the space was overcooled with an average PMV of −0.66 or below. Practical application: The effect of air distribution system design on human thermal comfort has been very complex to understand, as it involves different schemes and different diffuser discharge velocities. This study will help engineers and designers in designing better thermal environment for the occupants.

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Application Study of Cold Air Distribution System

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.732-733.548 ◽

2013 ◽

Vol 732-733 ◽

pp. 548-551 ◽

Cited By ~ 1

Author(s):

Xiao Ming Zhang ◽

Cheng Cai Sun ◽

Xiao Zhang ◽

Ji Zhi Li

Keyword(s):

Distribution System ◽

Thermal Environment ◽

Simulation Software ◽

Air Distribution ◽

Paper Briefly ◽

Application Study ◽

Cold Air ◽

Indoor Thermal Comfort ◽

Air Supply ◽

Air Diffusion

This paper briefly introduced the cold air distribution system principle and characteristics. Apply the simulation software to simulate air distribution and thermal environment of cold air supply room. Adopt Effective Draft Temperature (EDT) and Air Diffusion Performance Index (ADPI) to evaluate indoor thermal comfort.

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Analysis of Thermal Comfort and Contaminant Removal in an Office Room With Underfloor Air Distribution System

Heat Transfer: Volume 2 ◽

10.1115/ht2005-72437 ◽

2005 ◽

Author(s):

Son H. Ho ◽

Luis Rosario ◽

Muhammad M. Rahman

Keyword(s):

Relative Humidity ◽

Thermal Comfort ◽

Distribution System ◽

Air Distribution ◽

Contaminant Removal ◽

Case Scenario ◽

Steady State Condition ◽

Human Thermal Comfort ◽

Underfloor Air Distribution ◽

Occupied Zone

The study of human thermal comfort requires detailed information about distributions of air velocity, air temperature and relative humidity in an occupied zone. Air quality is related to the contaminant distributions and contaminant removal effectiveness in indoor environment. This paper presents an evaluation of thermal comfort and contaminant removal for an office setting with underfloor air distribution system by the use of computational fluid dynamics modeling. A typical single cubicle in a large office floor in steady state condition of airflow as well as heat and mass transfer is investigated for both cooling and heating scenarios. The model includes a typical cubicle in a large office floor with a chair, a desk with a personal computer on its top, and heat sources such as seated people, computer monitor and CPU, and lights. Air enters the occupied zone through an inlet located at the floor level supplying a vertical upward inflow. Five different locations of the inlet diffuser, three different inlet air speeds, and four different loads of heat loss through the floor slab in heating case scenario were considered. Distributions of velocity, temperature, relative humidity, and contaminant concentration in such cases were computed. The results were compared among various simulation cases and showed reasonable agreement with experimental data taken from related literature.

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Numerical Study on Coupled Operation of Stratified Air Distribution System and Natural Ventilation under Multi-Variable Factors in Large Space Buildings

Energies ◽

10.3390/en14238130 ◽

2021 ◽

Vol 14 (23) ◽

pp. 8130

Author(s):

Ziwen Dong ◽

Liting Zhang ◽

Yongwen Yang ◽

Qifen Li ◽

Hao Huang

Keyword(s):

Thermal Comfort ◽

Working Conditions ◽

Distribution System ◽

Distribution Systems ◽

Natural Ventilation ◽

Numerical Study ◽

Air Distribution ◽

Large Space ◽

Air Conditioners ◽

Air Supply

Stratified air distribution systems are commonly used in large space buildings. The research on the airflow organization of stratified air conditioners is deficient in terms of the analysis of multivariable factors. Moreover, studies on the coupled operation of stratified air conditioners and natural ventilation are few. In this paper, taking a Shanghai Airport Terminal departure hall for the study, air distribution and thermal comfort of the cross-section at a height of 1.6 m are simulated and compared under different working conditions, and the effect of natural ventilation coupling operation is studied. The results show that the air distribution is the most uniform and the thermal comfort is the best (predicted mean vote is 0.428, predicted percentage of dissatisfaction is 15.2%) when the working conditions are 5.9% air supply speed, 11 °C cooling temperature difference and 0° air supply angle. With the coupled operation of natural ventilation, the thermal comfort can be improved from Grade II to Grade I.

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Thermal Comfort Assessment of Underfloor vs. Overhead Air Distribution System

Journal of Applied Sciences ◽

10.3923/jas.2012.473.479 ◽

2012 ◽

Vol 12 (5) ◽

pp. 473-479 ◽

Cited By ~ 2

Author(s):

M. Aghakhani ◽

Gh. Eslami

Keyword(s):

Thermal Comfort ◽

Distribution System ◽

Air Distribution

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Operation Testing of an Advanced Personalized Ventilation System

Energies ◽

10.3390/en12091596 ◽

2019 ◽

Vol 12 (9) ◽

pp. 1596 ◽

Cited By ~ 3

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.

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Experimental study on coupling effect of indoor air temperature and radiant temperature on human thermal comfort in non-uniform thermal environment

Building and Environment ◽

10.1016/j.buildenv.2019.106387 ◽

2019 ◽

Vol 165 ◽

pp. 106387 ◽

Cited By ~ 3

Author(s):

Dengjia Wang ◽

Guixia Chen ◽

Cong Song ◽

Yanfeng Liu ◽

Wenfang He ◽

...

Keyword(s):

Experimental Study ◽

Thermal Comfort ◽

Air Temperature ◽

Indoor Air ◽

Thermal Environment ◽

Coupling Effect ◽

Human Thermal Comfort ◽

Radiant Temperature

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Experimental study on dynamic thermal environment of passenger compartment based on thermal evaluation indexes

Science Progress ◽

10.1177/0036850420942991 ◽

2020 ◽

Vol 103 (3) ◽

pp. 003685042094299

Author(s):

Liang Zhang ◽

Liangkui Qi ◽

Jianhua Liu ◽

Qingqing Wu

Keyword(s):

Thermal Comfort ◽

Air Temperature ◽

Prediction Accuracy ◽

Thermal Environment ◽

Temperature Model ◽

Equivalent Temperature ◽

Vote Model ◽

Evaluation Indexes ◽

Human Thermal Comfort ◽

Experimental Values

In this article, the thermal environment and the human thermal comfort of car cabin under different driving states in summer were studied experimentally. The weighted predictive mean vote model and the weighted equivalent temperature model were used for calculation and compared with the experimental values. The experimental results show that the air temperature and relative humidity distribution in cabin are affected by the space position and driving state. The temperature of the cabin seat, which is affected by solar radiation and crew, in the heating stage is slightly higher than the air temperature, while the cooling rate in the cooling stage is much lower than the air temperature. The predictive mean vote model and the equivalent temperature model are basically consistent with the actual thermal comfort of human body under the idle and driving conditions with the change of time. The prediction accuracy of the two models under the idle condition is higher than that under the driving condition, and the overall prediction accuracy of the equivalent temperature model is higher than that of the predictive mean vote model.

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Investigation on Airport Landscape Cooling Associated with Irrigation: A Case Study of Adelaide Airport, Australia

Sustainability ◽

10.3390/su12198123 ◽

2020 ◽

Vol 12 (19) ◽

pp. 8123

Author(s):

Jingming Qian ◽

Shujiang Miao ◽

Nigel Tapper ◽

Jianguang Xie ◽

Greg Ingleton

Keyword(s):

Global Warming ◽

Thermal Comfort ◽

Air Temperature ◽

Trial Period ◽

Land Utilization ◽

Irrigation Area ◽

Human Thermal Comfort ◽

Loading And Unloading ◽

Maximum Air Temperature

Extreme summertime heat is becoming a major issue for aircraft operations. As global temperatures continue to rise, some of the heaviest planes on the longest flights may eventually be unable to depart during the hottest part of summer days. During summer days, some airports have to reduce the payload of aircraft, including cargo and/or passengers in the hotter days of summer. Nonetheless, there is no existing body of research on the potential for airport cooling. Furthermore, extreme heat on the ground also affects airport workers; loading and unloading luggage and servicing platforms between flights could become more arduous. With global warming proceeding, it is becoming increasingly urgent to find a suitable strategy to cool airport environments, perhaps by irrigation of a vegetated landscape. All airports have large enclosed areas (usually of grass) acting as a buffer between airport activities and the adjacent industrial, commercial and residential land utilization. This paper describes the trial of irrigating the buffer area of Adelaide airport and analyzes the performance of irrigation cooling for Adelaide airport, examining whether this can benefit human thermal comfort. Results indicate that irrigation provides cooling, and the cooling effect reduces along with the increasing instance from the middle of the irrigation area. At 15:00, the average air temperature was 1.8 °C cooler in the middle of the irrigation area than in the non-irrigation area, and the relative humidity was 5.8% higher during the trial period. On an extremely hot day (the maximum air temperature was 45.4 °C), it was 1.5 °C cooler in the middle of the irrigation area than upwind the of irrigation area, and 0.8 °C cooler than downwind of the irrigation area at 13:00. Human thermal comfort (HTC) is unfavorable in the runway, but greater improvements can be made through promotion of irrigation.

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