scholarly journals Thermal Comfort Evaluation Using Linear Discriminant Analysis (LDA) and Artificial Neural Networks (ANNs)

Energies ◽  
2020 ◽  
Vol 13 (3) ◽  
pp. 538
Author(s):  
Katarzyna Gładyszewska-Fiedoruk ◽  
Maria Jolanta Sulewska
Keyword(s):  
Thermal Comfort ◽  
Air Temperature ◽  
Indoor Air ◽  
Thermal Conditions ◽  
Climatic Conditions ◽  
Test Results ◽  
Linear Discriminant ◽  
Comfort Evaluation ◽  
Questionnaire Surveys ◽  
Radiant Temperature

The thermal sensations of people differ from each other, even if they are in the same thermal conditions. The research was carried out in a didactic teaching room located in the building of the Faculty of Civil and Environmental Engineering in Poland. Tests on the temperature were carried out simultaneously with questionnaire surveys. The purpose of the survey was to define sensations regarding the thermal comfort of people in the same room, in different conditions of internal and external temperatures. In total 333 questionnaires were analyzed. After the discriminant and neural analyses it was found that it is not possible to forecast the thermal comfort assessment in the room based on the analyzed variables: gender, indoor air temperature, external wall radiant temperature, and outdoor air temperature. The thermal comfort assessments of men and women were similar and overlapped. The results of this study confirm that under the same thermal conditions about 85% of respondents assess thermal comfort as good, and about 15% of respondents assess thermal comfort as bad. The test results presented in this article are similar to the results of tests carried out by other authors in other climatic conditions.

scholarly journals Effects of vegetation covers for outdoor thermal improvement: A Case Study at Abubakar Tafawa Balewa University, Bauchi, Nigeria

2021 ◽  
Vol 29 (3) ◽  
Author(s):  
Kabiru Haruna Abdulkarim ◽  
Azmiah Abd Ghafar ◽  
Lee Yoke Lai ◽  
Ismail Said
Keyword(s):  
Air Temperature ◽  
Thermal Conditions ◽  
Atmospheric Temperature ◽  
Thermal Reduction ◽  
Climatic Conditions ◽  
Tree Canopy ◽  
Outdoor Spaces ◽  
Key Factor ◽  
Thermal Improvement ◽  
Radiant Temperature

Frequent increases in temperature and related consequences have been the trending phenomenon for over ten decades, with a general rise of about 0.740C. This study evaluates the effects of different percentage covers of tree canopies for outdoor thermal improvement of campus areas in Bauchi, Nigeria. Firstly, the study involves on-site measurement of existing features on the site and the climatic conditions. Secondly, performing simulation for evaluation of the plant-surface-atmosphere interactions with Envi-met Version 4.4.2. The vegetation effects were evaluated for outdoor air temperature and mean radiant temperature (MRT) reduction. It is found that the maximum air temperature reduction of 3.380C and 24.240C of MRT were achieved with up to 45% tree canopy coverage. The mean air temperature and MRT reduction of 0.630C and 4.800C were respectively achieved with the same percentage coverage of the canopies. However, it was found that the thermal reduction effects of vegetation do not apply to every hour of the day. In essence, proper planning and implementation of campus outdoor spaces is the key factor in improving its thermal conditions. Thus, adhering to the practical recommendations bring a significant improvement in ameliorating the rise in atmospheric temperature on campus outdoors.

scholarly journals KENYAMANAN TERMAL ADAPTIF MAHASISWA DI UNIVERSITAS SAINS DAN TEKNOLOGI JAYAPURA

2021 ◽  
Vol 9 (1) ◽  
pp. 17-23
Author(s):  
Indah Sari Zulfiana
Keyword(s):  
Thermal Comfort ◽  
Air Temperature ◽  
Adaptive Behavior ◽  
Environmental Parameters ◽  
Thermal Conditions ◽  
Climatic Conditions ◽  
High Humidity ◽  
Air Velocity ◽  
Adaptive Thermal Comfort ◽  
Thermal Preferences

To get good quality learning, a comfortable study room is needed both visually, audally and thermally. Thermal comfort is greatly influenced by the climatic conditions of a region. In areas with high daily air temperature, high humidity and low air velocity, it is difficult to produce thermal comfort with natural air conditioning. Jayapura City is one of the cities in Indonesia with daily air temperature and high humidity and low air velocity. Therefore, adaptive processes are needed to achieve thermal comfort in spaces, including study rooms. Each human's adaptive thermal comfort is different according to local climatic conditions. The purpose of this study was to determine the adaptive thermal comfort of students in naturally ventilated classrooms at the Jayapura University of Science and Technology (USTJ) in the city of Jayapura, Papua, namely students 'neutrality, acceptance and thermal preferences, as well as students' adaptive behavior in achieving thermal comfort. This research was conducted in one of USTJ's classrooms in Jayapura, Papua. Four environmental parameters were measured, namely temperature, humidity, wind speed, and mean radiant temperature (MRT). The data were obtained through filling out a questionnaire to 100 USTJ students during the space measurement. Thermal neutrality data were analyzed using regression analysis using SPSS software, while thermal acceptance and preference and adaptive behavior were analyzed based on the results of the questionnaire answers. The results showed that USTJ students' thermal neutrality was at 29.°C Ta or 29.55°C Top. all students can accept the thermal conditions of the room, but 59% of students choose to want the room to be cooler due to their thermal preferences. The adaptive behavior that is carried out is turning on the fan, picking up objects to be used as a fan, leaving the room and drinking more often.

Consideration of Operative Temperature in Design and Operation

2016 ◽  
Vol 861 ◽  
pp. 438-445
Author(s):  
Attila Kerekes ◽  
András Zöld
Keyword(s):  
Regression Analysis ◽  
Air Temperature ◽  
Indoor Air ◽  
Thermal Conditions ◽  
Mean Radiant Temperature ◽  
Operative Temperature ◽  
Pros And Cons ◽  
Radiant Temperature ◽  
Overall Heat Loss Coefficient ◽  
Simplified Calculation

In order to provide appropriate thermal conditions current national regulations prescribe operative temperature as the base of design and operation. In simplified calculation procedure prescribed operative temperature can be provided using a corrected air temperature. Interrelation of operative and indoor air temperature has been investigated in function of overall heat loss coefficient and glazed ratio. Based on regression analysis necessary corrections in function of the above parameters are investigated, the consequences of neglected Mean Radiant Temperature are analysed. Operative temperature represents a control problem, too: disregarding the sensor itself its position in the room, the uneven distribution of radiant field in one room and in the rooms of a flat requires compromises. The possible solutions, their pros and cons are presented.

Evaluation of Thermal Comfort for Workers at the Construction Site in a Block-Modular Building Made of Sandwich Panels

2019 ◽  
pp. 60-65
Keyword(s):  
Thermal Comfort ◽  
Air Temperature ◽  
Experimental Studies ◽  
Sandwich Panels ◽  
Thermal Characteristics ◽  
Internal Surface ◽  
Thermal Conditions ◽  
Climatic Conditions ◽  
Winter Period ◽  
Construction Site

The purpose of this work is to assess the thermal comfort of a block-modular building on the construction site. The experimental studies for determining the thermal conditions of the cabins in the winter and the summer time of the city of Zhengzhou was carried out at different locations of the modular house made of sandwich panels for determining the category of living comfort. The variations of air temperature and relative humidity in the cabin were analyzed. The difference between outdoor and indoor air temperatures, as well as the changes in air temperature and heat flux on the internal surface of the different walls of the building by their location relative to the cardinal directions were considered. Reasons for decreasing the comfort in the room and the attenuation of the experimental amplitude of the outdoor temperature fluctuations in the enclosing structure as well as the thermal properties of enclosing structures of the block-modular building under different climatic conditions were studied. It is shown that it is necessary to take into account the reflection of heat inside the premises and their ventilation when designing enclosing structures of mobile buildings. It is revealed that in the winter period for energy saving it is necessary to increase in addition thermal characteristics of the western wall of domestic buildings.

scholarly journals Energy-saving potential of intermittent heating system: Influence of composite phase change wall and optimization strategy

2020 ◽  
pp. 014459872096921
Author(s):  
Yanru Li ◽  
Enshen Long ◽  
Lili Zhang ◽  
Xiangyu Dong ◽  
Suo Wang
Keyword(s):  
Energy Consumption ◽  
Thermal Comfort ◽  
Phase Change ◽  
Air Temperature ◽  
Indoor Air ◽  
Thermal Environment ◽  
Optimization Strategy ◽  
Indoor Thermal Environment ◽  
Indoor Thermal Comfort ◽  
Intermittent Heating

In the Yangtze River zone of China, the heating operation in buildings is mainly part-time and part-space, which could affect the indoor thermal comfort while making the thermal process of building envelope different. This paper proposed to integrate phase change material (PCM) to building walls to increase the indoor thermal comfort and attenuate the temperature fluctuations during intermittent heating. The aim of this study is to investigate the influence of this kind of composite phase change wall (composite-PCW) on the indoor thermal environment and energy consumption of intermittent heating, and further develop an optimization strategy of intermittent heating operation by using EnergyPlus simulation. Results show that the indoor air temperature of the building with the composite-PCW was 2–3°C higher than the building with the reference wall (normal foamed concrete wall) during the heating-off process. Moreover, the indoor air temperature was higher than 18°C and the mean radiation temperature was above 20°C in the first 1 h after stopping heating. Under the optimized operation condition of turning off the heating device 1 h in advance, the heat release process of the composite-PCW to the indoor environment could maintain the indoor thermal environment within the comfortable range effectively. The composite-PCW could decrease 4.74% of the yearly heating energy consumption compared with the reference wall. The optimization described can provide useful information and guidance for the energy saving of intermittently heated buildings.

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.

scholarly journals Field Study Of A Radiant Heating System For Sleep Thermal Comfort And Potential Energy Saving

2021 ◽  
Author(s):  
Christopher L. K. Wang
Keyword(s):  
Potential Energy ◽  
Thermal Comfort ◽  
Energy Saving ◽  
Energy Savings ◽  
Thermal Environment ◽  
Residential Buildings ◽  
Thermal Conditions ◽  
Heating System ◽  
The Body ◽  
Radiant Temperature

As sleep is unconscious, the traditional definition of thermal comfort with conscious judgment does not apply. In this thesis sleep thermal comfort is defined as the thermal condition which enables sleep to most efficiently rejuvenate the body and mind. A comfort model was developed to stimulate the respective thermal environment required to achieve the desired body thermal conditions and a new infrared sphere method was developed to measure mean radiant temperature. Existing heating conditions according to building code conditions during sleeping hours was calculated to likely overheat a sleeping person and allowed energy saving potential by reducing nighttime heating set points. Experimenting with existing radiantly and forced air heated residential buildings, it was confirmed that thermal environment was too hot for comfortable sleep and that the infrared sphere method shows promise. With the site data, potential energy savings were calculated and around 10% of energy consumption reduction may be achieved during peak heating.

scholarly journals An Interactive Task Conditioning System Featuring Personal Comfort Models and Non-Intrusive Sensing Techniques: A Field Study in Shanghai

Technologies ◽  
2021 ◽  
Vol 9 (4) ◽  
pp. 90
Author(s):  
Siliang Lu ◽  
Erica Cochran Hameen
Keyword(s):  
Thermal Comfort ◽  
Field Study ◽  
Air Temperature ◽  
Indoor Air ◽  
Thermal Environment ◽  
Thermal Sensation ◽  
New Paradigm ◽  
Dynamic Task ◽  
Current Task ◽  
Open Plan

Heating, ventilation and air-conditioning (HVAC) systems play a key role in shaping office environments. However, open-plan office buildings nowadays are also faced with problems like unnecessary energy waste and an unsatisfactory shared indoor thermal environment. Therefore, it is significant to develop a new paradigm of an HVAC system framework so that everyone could work under their preferred thermal environment and the system can achieve higher energy efficiency such as task ambient conditioning system (TAC). However, current task conditioning systems are not responsive to personal thermal comfort dynamically. Hence, this research aims to develop a dynamic task conditioning system featuring personal thermal comfort models with machine learning and the wireless non-intrusive sensing system. In order to evaluate the proposed task conditioning system performance, a field study was conducted in a shared office space in Shanghai from July to August. As a result, personal thermal comfort models with indoor air temperature, relative humidity and cheek (side face) skin temperature have better performances than baseline models with indoor air temperature only. Moreover, compared to personal thermal satisfaction predictions, 90% of subjects have better performances in thermal sensation predictions. Therefore, personal thermal comfort models could be further implemented into the task conditioning control of TAC systems.

scholarly journals Mitigation Strategies for Overheating and High Carbon Dioxide Concentration within Institutional Buildings: A Case Study in Toronto, Canada

Buildings ◽  
2020 ◽  
Vol 10 (7) ◽  
pp. 124 ◽  
Author(s):  
Claire Tam ◽  
Yuqing Zhao ◽  
Zaiyi Liao ◽  
Lian Zhao
Keyword(s):  
Carbon Dioxide ◽  
Air Quality ◽  
Indoor Air Quality ◽  
Air Temperature ◽  
Indoor Air ◽  
Indoor Environment ◽  
Thermal Conditions ◽  
Co2 Concentration ◽  
Hvac System

Indoor air quality and thermal conditions are important considerations when designing indoor spaces to ensure occupant health, satisfaction, and productivity. Carbon dioxide (CO2) concentration and indoor air temperature are two measurable parameters to assess air quality and thermal conditions within a space. Occupants are progressively affected by the indoor environment as the time spent indoors prolongs. Specifically, there is an interest in carrying out investigations on the indoor environment through surveying existing Heating, Ventilation, Air Conditioning (HVAC) system operations in classrooms. Indoor air temperature and CO2 concentration in multiple lecture halls in Toronto, Canada were monitored; observations consistently show high indoor air temperature (overheating) and high CO2 concentration. One classroom is chosen as a representative case study for this paper. The results verify a strong correlation between the number of occupants and the increase in air temperature and CO2 concentration. Building Energy Simulation (BES) is used to investigate the causes of discomfort in the classroom, and to identify methods for regulating the temperature and CO2 concentration. This paper proposes retro-commissioning strategies that could be implemented in institutional buildings; specifically, the increase of outdoor airflow rate and the addition of occupancy-based pre-active HVAC system control. The proposed retrofit cases reduce the measured overheating in the classrooms by 2-3 °C (indoor temperature should be below 23 °C) and maintain CO2 concentration under 900 ppm (the CO2 threshold is 1000 ppm), showing promising improvements to a classroom’s thermal condition and indoor air quality.

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