scholarly journals Thermal Perception in Mild Climate: Adaptive Thermal Models for Schools

2019 ◽  
Vol 11 (14) ◽  
pp. 3948 ◽  
Author(s):  
Miguel Ángel Campano ◽  
Samuel Domínguez-Amarillo ◽  
Jesica Fernández-Agüera ◽  
Juan José Sendra

A comprehensive assessment of indoor environmental conditions is performed on a representative sample of classrooms in schools across southern Spain (Mediterranean climate) to evaluate the thermal comfort level, thermal perception and preference, and the relationship with HVAC systems, with a comparison of seasons and personal clothing. Almost fifty classrooms were studied and around one thousand pool-surveys distributed among their occupants, aged 12 to 17. These measurements were performed during spring, autumn, and winter, considered the most representative periods of use for schools. A new proposed protocol has been developed for the collection and subsequent analysis of data, applying thermal comfort indicators and using the most frequent predictive models, rational (RTC) and adaptive (ATC), for comparison. Cooling is not provided in any of the rooms and natural ventilation is found in most of the spaces during midseasons. Despite the existence of a general heating service in almost all classrooms in the cold period, the use of mechanical ventilation is limited. Heating did not usually provide standard set-point temperatures. However, this did not lead to widespread complaints, as occupants perceive the thermal environment as neutral—varying greatly between users—and show a preference for slightly colder environments. Comparison of these thermal comfort votes and the thermal comfort indicators used showed a better fit of thermal preference over thermal sensation and more reliable results when using regional ATC indicators than the ASHRAE adaptive model. This highlights the significance of inhabitants’ actual thermal perception. These findings provide useful insight for a more accurate design of this type of building, as well as a suitable tool for the improvement of existing spaces, improving the conditions for both comfort and wellbeing in these spaces, as well as providing a better fit of energy use for actual comfort conditions.

2020 ◽  
Vol 3 (1) ◽  
pp. p1
Author(s):  
Jad Hammoud ◽  
Elise Abi Rached

The increasing of energy demands has considerably increased the requirements for new and traditional buildings in different climate zones. Unprecedented heat waves have increased climate temperature, in particular, in moderate climate zones such as Lebanon. In Beirut, only the residential sector consumes 50% of total electricity consumption. HVAC (Heating, Ventilation and Air conditioning) systems are used to reach acceptable thermal comfort levels in the new residential buildings. In case of the traditional bourgeoisie houses in Beirut, there are no discussions about the use of HVAC systems to achieve the required thermal comfort level. Thus, to reach an acceptable thermal comfort level, these houses which already contain natural ventilation system shall adapt the modern thermal comfort requirements and thermal comfort strategies and technologies where their architectural features and existing materials condition the available solutions. In order to identify the best options within the possible intervention lines (envelopes, passive strategies, equipment, renewable energy systems), it is necessary to perceive the real performance of this type of houses. In this context, the article presents the results of the study of thermal performance and comfort in a three case studies located in Beirut. Detailed field data records collected are analyzed, with a view to identify the indoor thermal environment with respect to outdoor thermal environment in different seasons. Monitoring also included measurement of hygrothermal parameters and surveys of occupant thermal sensation.


2021 ◽  
Vol 39 (1) ◽  
pp. 275-291
Author(s):  
Md Sarfaraz Alam ◽  
Urmi Ravindra Salve

There are ample literature studies available, focusing on hot-humid built environment, which have achieved an increase in thermal comfort conditions by proper installation of ventilation-systems. The present thermal comfort study has been carried out in the kitchen environment of a non-air-conditioned railway pantry car in Indian Railways. The purpose is to enhance thermal comfort level under the currently applied ventilation system inside the kitchen of pantry car by determining the standard effective temperature (SET) index. During the summer and winter seasons, a field study was carried out to obtain the value of air temperature, globe temperature, relative humidity, and air velocity inside the pantry car for estimation of the SET index. A computational fluid dynamics (CFD) analysis was used to obtain a better-modified case model of the pantry car kitchen for the improvement of thermal comfort. The design interventions for the pantry car kitchen were created, with emphasis on increasing energy efficiency based on low-power consumption air ventilation system. The study results indicated that, modified case-I model has a better ventilation design concept as compare to the existing and other models, which increased the air velocity and significantly decreased the air temperature inside the kitchen of pantry car at all cooking periods. A value of SET (28.6–30℃) was found with a comfortable thermal sensation within all cooking periods, which is better for the pantry car workers. This finding suggests a sustainable improvement in the thermal environment of the "non-air-conditioned" pantry car kitchen in the Indian Railways, which can be applied immediately.


2018 ◽  
Vol 225 ◽  
pp. 01003 ◽  
Author(s):  
Kelly Koh ◽  
Hussain H. Al-Kayiem ◽  
Jundika C. Kurnia

As a lot of people spend their time indoor, indoor thermal comfort will affect the performance of the occupants in terms of health, comfort and productivity. This paper aims to investigate the thermal comfort of an office building constructed using low cost materials in tropical climate condition. That has been achieved by investigating the PMV using the CBE thermal comfort tool in the post-graduate office building in the solar research site in UTP. The experimental measurements have been conducted at two different cases; without ventilation and with air-conditioned in the office building. The thermal comfort of the office building is assessed by using the ASHRAE thermal sensation scale. Results have demonstrated that the office room without ventilation is hot and not suitable for occupants to work at such thermal environment. Thermal comfort of the room with air-conditioning is warm and is slightly better than the room without ventilation as the PMV has been improved by around 60%. However, the acceptable thermal comfort level in the low-cost material office building is yet to be achieved.


2019 ◽  
Vol 29 (6) ◽  
pp. 851-859 ◽  
Author(s):  
Michael Fabozzi ◽  
Alessandro Dama

Maintaining a satisfactory thermal environment is of primary importance, especially when the goal is to maximize learning such as in schools or universities. This paper presents a field study conducted in Milan during summer 2017 in 16 classrooms of Politecnico di Milano, including both naturally ventilated (NV) and air-conditioned (AC) environments. This study asked 985 students to report their thermal perception and their responses were evaluated according to the measured thermal comfort parameters to assess the prediction as given by Fanger and adaptive models, according to ANSI/ASHRAE 55-2017 and EN 15251:2007 standards. Furthermore, an analysis regarding potential effects of gender in comfort perception was performed. The results confirmed the fitness of Fanger’s model for the prediction of occupants’ thermal sensations in AC classrooms with a reasonable accuracy. In NV classrooms, the Adaptive model was proven to be suitable for predicting students’ comfort zone according to ASHRAE 55 Standard, while the adaptive comfort temperatures recommended by EN 15251 were not acceptable for a large number of students. No significant differences in thermal comfort perception between genders have been observed, except for two NV classrooms in which females’ thermal sensation votes had resulted closer to neutrality in comparison to males, who expressed a warmer thermal sensation.


2021 ◽  
Vol 13 (22) ◽  
pp. 12764
Author(s):  
Xinzhi Gong ◽  
Qinglin Meng ◽  
Yilei Yu

It is important to consider reducing energy use while improving occupants’ indoor thermal comfort. The actual thermal comfort needs and demands should be considered to determine the indoor thermal environment design. In previous studies, research has not been carried out on thermal comfort in karst areas. Thus, a long-term field investigation was carried out on multi-storey residential buildings in the karst area of Guilin city centre during summer (from August 2019 to September 2019) and winter (from December 2019 to January 2020). In this study, the indoor thermal environments of three categories of dwellings were analysed. A total of 77 residential buildings with 144 households were randomly selected, and 223 occupants from 18 to 80 years old participated. A total of 414 effective questionnaires were collected from the subjects. The results show that there was an obvious conflict between the predicted mean vote (PMV) and the thermal sensation vote (TSV). The neutrality temperatures calculated by the regression method were 24.2 °C in summer and 16.2 °C in winter. The thermal comfort range was observed at operative temperatures of 20.9–27.5 °C in summer and 12.2–20.1 °C in winter. The desired thermal sensation for people in the Guilin karst area was not always reflected in the thermal neutrality range. A preference for warmness was identified in the survey.


2019 ◽  
Vol 12 (1) ◽  
pp. 170
Author(s):  
Chorpech Panraluk ◽  
Atch Sreshthaputra

In Thailand, many government buildings and facilities are adapted to serve as Multipurpose Senior Centers (MSCs). However, most of them have been used without taking into account of thermal comfort of occupants. The present research aimed to develop guidelines for improving suitable indoor environment for the Thai elderly in hot season and analyze energy use of the 3 case-study MSCs. Both field study and climate-controlled chamber study were conducted. The obtained data were analyzed to develop the equation for predicting the thermal sensation, which would be inputted in the scSTREAM program for analysis purposes. The energy use was evaluated using the DOE-2 program. The results suggested that during 8:00 a.m.–12:00 p.m., natural ventilation should be used together with orbit fans to produce an actual air velocity of 0.64–0.73 m/s. From 12:00 p.m. to 4:00 p.m., air conditioners should set at 26.00–26.50 °C with an actual air velocity of 0.06–0.22 m/s. The results also showed that the developed guidelines could improve the level of thermal comfort from “slightly cool” to “neutral” and reduce energy use in hot season by 16.56% due to the reduction of cooling load and fan operation of air conditioning systems. Moreover, energy consumption in MSCs are also affected by the building parameters. These findings can be applied as guidelines for improving a large number of MSCs in Thailand.


2013 ◽  
Vol 2013 ◽  
pp. 1-8 ◽  
Author(s):  
Chuang-Hung Lin ◽  
Tzu-Ping Lin ◽  
Ruey-Lung Hwang

The paper is an effort toward thermal comfort assessment for urban parks under the climatic conditions of Taiwan to help architects achieve better climatic design. Field interviews, observations, and micrometeorological measurements were conducted in this study. The WBGT was used as the thermophysiological index to investigate the effects of thermal conditions on visitor’s thermal perception and adaptive behavior in outdoor urban spaces. In this study, behavioral adaptations used by visitors as a means of achieving comfort were evaluated. Observational results showed that the overall attendance was influenced by sun and thermal conditions. There was a robust relationship between thermal sensation votes, as well as thermal acceptability, and thermal environment, in terms of WBGT. The upper and lower limits of 80% acceptability are 26°C WBGT and 20°C WBGT, respectively.


Technologies ◽  
2021 ◽  
Vol 9 (4) ◽  
pp. 90
Author(s):  
Siliang Lu ◽  
Erica Cochran Hameen

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.


2021 ◽  
pp. 1420326X2110345
Author(s):  
Marika Vellei ◽  
William O’Brien ◽  
Simon Martinez ◽  
Jérôme Le Dréau

Recent research suggests that a time-varying indoor thermal environment can lead to energy savings and contribute to boost buildings' energy flexibility. However, thermal comfort standardization has so far considered thermal comfort criteria as constant throughout the day. In general, very little attention has been given to the ‘ time of day' variable in the context of thermal comfort research. In this paper, we show some evidence of a time-varying thermal perception by using: (1) data from about 10,000 connected Canadian thermostats made available as part of the ‘ Donate Your Data' dataset and (2) about 22,000 samples of complete (objective + ‘ right-here-right-now' subjective) thermal comfort field data from the ASHRAE I and SCATs datasets. We observe that occupants prefer colder thermal conditions at 14:00 and progressively warmer ones in the rest of the day, indistinctively in the morning and evening. Neutral temperature differences between 08:00 and 14:00 and 14:00 and 20:00 are estimated to be of the order of 2°C. We hypothesize that the human circadian rhythm is the cause of this difference. Nevertheless, the results of this study are only based on observational data. Thermal comfort experiments in controlled environmental chambers are required to confirm these findings and to better elucidate the effects of light and circadian timing and their interaction on thermal perception.


2020 ◽  
Vol 15 (3) ◽  
pp. 163-170
Author(s):  
Rajan KC ◽  
Hom Bahadur Rijal ◽  
Masanori Shukuya ◽  
Kazui Yoshida

The energy use in residential dwellings has been increasing due to increasing use of modern electric appliances to make the lifestyle easier, entertaining and better. One of the major purposes of indoor energy use is for improving indoor thermal environment for adjusting thermal comfort. Along with the use of passive means like the use of mechanical devices, the occupants in any dwellings use active means such as the use of natural ventilation, window opening, and clothing adjustment. In fact, the use of active means when the outdoor environment is good enough might be more suitable to improve indoor thermal environment than the use of mechanical air conditioning units, which necessarily require electricity. Therefore, the people in developing countries like Nepal need to understand to what extent the occupants can use active means to manage their own indoor thermal comfort. The use of active means during good outdoor environment might be an effective way to manage increasing energy demand in the future. We have made a field survey on the occupants’ adaptive behaviors for thermal comfort in a Japanese condominium equipped with Home Energy Management System (HEMS). Online questionnaire survey was conducted in a condominium with 356 families from November 2015 to October 2016 to understand the occupants’ behaviors. The number of 17036 votes from 39 families was collected. The indoor air temperature, relative humidity and illuminance were measured at the interval of 2-10 minutes to know indoor thermal environmental conditions. The occupants were found using different active behaviors for thermal comfort adjustments even in rather harsh summer and winter. Around 80% of the occupants surveyed opened windows when the outdoor air temperature was 30⁰C in free running (FR) mode and the clothing insulation was 0.93 clo when the outdoor air temperature was 0⁰C. The result showed that the use of mechanical heating and cooling was not necessarily the first priority to improve indoor thermal environment. Our result along with other results in residential buildings showed that the adaptive behaviors of the occupants are one of the primary ways to adjust indoor thermal comfort. This fact is important in enhancing the energy saving building design.


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