scholarly journals Hue-Heat Hypothesis: A Step forward for a Holistic Approach to IEQ

2019 ◽  
Vol 111 ◽  
pp. 02038 ◽  
Author(s):  
Francesca Romana d’Ambrosio Alfano ◽  
Laura Bellia ◽  
Francesca Fragliasso ◽  
Boris Igor Palella ◽  
Giuseppe Riccio
Keyword(s):  
Thermal Comfort ◽  
Energy Savings ◽  
Thermal Sensation ◽  
Holistic Approach ◽  
Spectral Irradiance ◽  
Light Sources ◽  
Thermal Perception ◽  
General Increase ◽  
Neutral Conditions ◽  
Stimulation Of

For many years different human factors contributing to the IEQ have been studied separately. Concerning thermal perception, despite it is almost accepted that thermal comfort can be influenced by concomitant stimulation of non-tactile modalities, relatively few investigations have succeeded in delineating non-tactile stimulations as the visual ones. The hue-heat hypothesis is based on the idea that, when spectral irradiance pattern at the observer’s eye shows a great amount of short wavelengths, the space is perceived as cooler. Conversely, when long wavelengths are predominant, the space is perceived as warmer. This means that operating on light characteristics could help in improving thermal comfort for the occupants with possible energy savings obtained by acting on the set-point temperature of HVAC systems. To verify this hypothesis, this paper will deal with a subjective investigation carried out in a special mechanically conditioned test room equipped with white-tuning LED sources. Investigated subjects have been exposed to two different light scenes consisting of warm (3000 K) and cool light sources (6000 K) at a fixed task illuminance value. Preliminary results seem to demonstrate that cool light is effective in shifting to cool the perceived thermal sensation with a general increase of people under neutral conditions.

Some evidence of a time-varying thermal perception

2021 ◽  
pp. 1420326X2110345
Author(s):  
Marika Vellei ◽  
William O’Brien ◽  
Simon Martinez ◽  
Jérôme Le Dréau
Keyword(s):  
Thermal Comfort ◽  
Energy Savings ◽  
Thermal Environment ◽  
Thermal Conditions ◽  
Time Of Day ◽  
Time Varying ◽  
Thermal Perception ◽  
Indoor Thermal Environment ◽  
Human Circadian Rhythm ◽  
Comfort Criteria

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.

scholarly journals Assessing the indoor thermal comfort of a toll station

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.

Subjective Evaluation of Thermal Comfort Using an Air Recirculation Device

1983 ◽  
Vol 27 (8) ◽  
pp. 751-756
Author(s):  
David A. VanDyke ◽  
Frederick H. Rohles ◽  
Michael P. Webster
Keyword(s):  
Thermal Comfort ◽  
Energy Demand ◽  
Energy Savings ◽  
Rating Scale ◽  
Thermal Sensation ◽  
Subjective Evaluation ◽  
Comfort Level ◽  
National Bureau ◽  
Environmental Laboratory ◽  
Fan Speed

To determine the effectiveness of a small fan in enhancing thermal comfort in an open office, eight subjects were studied at 24.4 C (76F), 26.1 C (79F), and 27.8 C (82F) (all at 50% RH), in an environmental laboratory where each workstation was equipped with a small variable speed fan. Control trials were run at all three temperatures without the use of the fan. Three subjective responses were measured: thermal sensation (a nine category rating scale), thermal comfort (a seven pair semantic differential scale), and temperature preference. During fan tests, subjects were allowed to adjust the fan speed to their preference at 15 minute intervals. Results showed that use of the fan could allow a 3°F temperature increase while maintaining the same comfort level, or increase comfort at temperatures of 79°F and up. The 3°F increase in temperature would result in a 9% energy savings, based on the National Bureau of Standards suggestion of a reduction in air conditioning energy demand of 6% per °C or 3% per °F. The study also shows that users prefer a fan that is adjustable in speed and placement.

Indoor Thermal Comfort and its Effect on Building Energy Consumption

2011 ◽  
Vol 71-78 ◽  
pp. 3516-3519 ◽  
Author(s):  
Xue Bin Yang ◽  
De Fa Sun ◽  
Xiang Jiang Zhou ◽  
Ling Ling Cai ◽  
Ying Ji
Keyword(s):  
Energy Consumption ◽  
Thermal Comfort ◽  
Energy Savings ◽  
Thermal Sensation ◽  
Building Energy ◽  
Building Energy Consumption ◽  
Predicted Mean Vote ◽  
Indoor Thermal Comfort ◽  
Air Speed ◽  
Comfort Parameters

The indoor thermal comfort and its effect on building energy consumption have been conducted by literature reviewing in the study. The linear relationship and the related formulations of various thermal comfort indictors are summarized to evaluate the human comfort. These parameters include predicted mean vote, thermal sensation vote, adaptive predicted mean vote, thermal comfort vote, and thermal acceptability. Under different climatic or regional conditions, both relationships between thermal comfort parameters and indoor or outdoor air temperature, and between comfort vote and another comfort parameter, are summarized for their definition and formulation. The comfort parameters such as local air speed, neutral temperature, PMV set point and others will directly impact the building energy usage. It is of significance to seek an optimal alternative for energy savings.

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
Keyword(s):  
Thermal Comfort ◽  
Natural Ventilation ◽  
Energy Use ◽  
Thermal Environment ◽  
Thermal Sensation ◽  
Comfort Level ◽  
Thermal Perception ◽  
Accurate Design ◽  
Almost All ◽  
Autumn And Winter

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.

scholarly journals Determination of Thermal Comfort Zones through Comparative Analysis between Different Characterization Methods of Thermally Dissatisfied People

Buildings ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 320
Author(s):  
Pedro Filipe da Conceição Pereira ◽  
Evandro Eduardo Broday
Keyword(s):  
Thermal Comfort ◽  
Air Conditioning ◽  
Energy Savings ◽  
Thermal Sensation ◽  
Probit Model ◽  
Energy Performance ◽  
Indoor Environmental Quality ◽  
Characterization Methods ◽  
American Society

In order to maintain thermal comfort and preserve indoor environmental quality, people use heating, ventilation and air-conditioning (HVAC) systems inside buildings. However, buildings must be prepared not only to provide adequate thermal comfort to their occupants but also to align strategies that enable better energy performance. Thus, this work aimed to establish thermal comfort zones (TCZ) through different characterization methods of thermally dissatisfied people. Responses were collected from 481 students, through the application of questionnaires in classrooms, during the Brazilian winter of 2019. Three methods for determining the actual percentage of dissatisfied (APD) were adopted, which generated three different equations, namely: APD_1; APD_2 and APD_3, based on the original Predicted Percentage of Dissatisfied (PPD) equation. By using the probit model, three TCZ were calculated: 17.73–22.4 °C (APD_1); 20.71–20.93 °C (APD_2) and 17.89–24.83 °C (APD_3). In addition, a comfort zone based on the linear regression between the thermal sensation votes and the operative temperature was determined (18.77–22.69 °C). All thermal comfort zones resulting from this work have colder temperatures than that indicated by the American Society of Heating, Refrigerating and Air-Conditioning Engineers - ASHRAE (2017) of 23–26 °C for the winter, showing the potential for energy savings from the adoption of this type of strategy, while maintaining thermal comfort.

scholarly journals Field study on thermal comfort in naturally ventilated and air-conditioned university classrooms

2019 ◽  
Vol 29 (6) ◽  
pp. 851-859 ◽  
Author(s):  
Michael Fabozzi ◽  
Alessandro Dama
Keyword(s):  
Thermal Comfort ◽  
Field Study ◽  
Thermal Environment ◽  
Thermal Sensation ◽  
Thermal Perception ◽  
Adaptive Models ◽  
Adaptive Comfort ◽  
Comfort Perception ◽  
Comfort Parameters ◽  
University Classrooms

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.

scholarly journals User Perception of Indoor Temperature and Preferences in Energy-Efficient Office Renovation Cases in the Netherlands

2019 ◽  
Vol 111 ◽  
pp. 03007
Author(s):  
Minyoung Kwon ◽  
Andy van den Dobbelsteen ◽  
Hilde Remøy
Keyword(s):  
Thermal Comfort ◽  
Energy Efficient ◽  
Thermal Sensation ◽  
Quality Data ◽  
Thermal Perception ◽  
Indoor Temperature ◽  
Seasonal Adaptation ◽  
Adaptive Comfort ◽  
Globe Temperature ◽  
Occupant Satisfaction

A comfortable indoor environment is one of the primary conditions of buildings. A majority of studies have attempted to compare occupant satisfaction of green-certificated offices and conventional offices. However, comparison of occupant perception with the adaptive comfort model may show differences and provide recommendations for the globe temperature in comfort. The purpose of this paper is to investigate the seasonal adaptation to indoor temperature, and to report the results of users’ thermal perception surveys on energy efficient renovated office buildings. This work compares occupants’ perception of indoor thermal quality. Data of indoor temperature were collected for 2 weeks in three seasons: summer, winter, and mid-season. Monitored indoor temperatures were compared with occupants’ thermal sensation, preference, and satisfaction regarding thermal comfort. The research found the relationship between indoor temperature and occupants’ thermal sensation. Results show that occupants perceived thermal quality better in renovated offices compared to non-renovated ones, but they do not always experience better thermal comfort than people in a non-renovated office.

scholarly journals Analyzing the Time-Varying Thermal Perception of Students in Classrooms and Its Influencing Factors from a Case Study in Xi’an, China

Buildings ◽  
2022 ◽  
Vol 12 (1) ◽  
pp. 75
Author(s):  
Yongkai Sun ◽  
Xi Luo ◽  
Hui Ming
Keyword(s):  
Influencing Factors ◽  
Energy Savings ◽  
Thermal Sensation ◽  
Activity Levels ◽  
Time Varying ◽  
Thermal Perception ◽  
Temperature Changes ◽  
Spatial Environment ◽  
Activity State ◽  
Questionnaire Surveys

Owing to movement in the spatial environment and changes in activity levels, students’ thermal perception is time varying in classrooms throughout different periods of the day. However, previous studies have rarely considered the time-varying thermal perception in different periods of the day, which may cause discomfort for students and lead to energy wastage. Therefore, a study was conducted to investigate the time-varying thermal perception of students and its influencing factors in different classes of the day. In addition, the differences in students’ adaptive behaviors in different periods were also explored. A total of 578 university students were surveyed using questionnaire surveys during the heating season in Xi’an, China. The following results can be obtained: (1) The thermal sensation vote and thermal preference vote values in the afternoon were significantly higher than those in the morning. At the start of the first class in the morning/afternoon, the thermal sensation of the students had the highest sensitivity to outdoor temperature changes. (2) The students’ thermal perception was greatly affected by the preclass activity state at the start of the first class in the morning/afternoon. However, in other periods, the above phenomenon was not obvious. (3) In the afternoon, the frequency of clothing adjustment was greater than that in the morning, and this behavior would significantly affect the students’ thermal sensation. (4) Compared with the current classroom heating strategy, the heating strategy of dynamically adjusting the indoor set temperature according to the time-varying characteristics of the students can theoretically achieve energy savings of 25.6%.

Enhancing Thermal Comfort with Ceiling Fans

1982 ◽  
Vol 26 (2) ◽  
pp. 118-120 ◽  
Author(s):  
Frederick H. Rohles ◽  
Stephan A. Konz ◽  
Byron W. Jones
Keyword(s):  
Thermal Comfort ◽  
Energy Demand ◽  
Air Conditioning ◽  
Energy Savings ◽  
Rating Scale ◽  
Thermal Sensation ◽  
National Bureau ◽  
Category Rating ◽  
Temperature Preference ◽  
Subjective Responses

To determine the effectiveness of ceiling fans in enhancing comfort, 256 subjects were examined at 24.4 C (76 F), 26.1 C (79 F), 27.8 C (82 F), and 29.4 C (85 F) (all at 50% rh), in an environmental chamber that was equipped with a ceiling fan that produced four velocity conditions: 0.15 m/s (30 fpm), 0.25 m/s (50 fpm), 0.46 m/s (90 fpm), and 1.02 m/s (200 fpm). A fifth velocity, in which the fan was not employed, was 0.06 m/s (10 fpm); this served as the control velocity. Three subjective responses were measured: thermal sensation (a 9-category rating scale), thermal comfort (a 7-pair semantic differential scale), and a question on temperature preference. The results showed that an air plume from a ceiling fan whose velocity is between 0.5 and 1.0 m/s (90 and 200 fpm) compensates for a 2.8–3.3°C (5–6°F) temperature change; this represents an energy savings of 15–18% when based on the National Bureau of Standards' suggestion of a reduction in air conditioning energy demand of 6% per °C or 3% per °F. It also concluded that a ceiling fan may extend the upper limit of the summer comfort envelope from 26.1 to 29.4 C (79 to 85 F) and that the turbulent and variable characteristics of the air plume of the ceiling fan may be its major comfort-producing attribute.

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