ArticleLiterature Review

Forty years of Fanger's model of thermal comfort: Comfort for all?

Authors:
To read the full-text of this research, you can request a copy directly from the author.

Abstract

Abstract Abstract The predicted mean vote (PMV) model of thermal comfort, created by Fanger in the late 1960s, is used worldwide to assess thermal comfort. Fanger based his model on college-aged students for use in invariant environmental conditions in air-conditioned buildings in moderate thermal climate zones. Environmental engineering practice calls for a predictive method that is applicable to all types of people in any kind of building in every climate zone. In this publication, existing support and criticism, as well as modifications to the PMV model are discussed in light of the requirements by environmental engineering practice in the 21st century in order to move from a predicted mean vote to comfort for all. Improved prediction of thermal comfort can be achieved through improving the validity of the PMV model, better specification of the model’s input parameters, and accounting for outdoor thermal conditions and special groups. The application range of the PMV model can be enlarged, for instance, by using the model to assess the effects of the thermal environment on productivity and behavior, and interactions with other indoor environmental parameters, and the use of information and communication technologies. Even with such modifications to thermal comfort evaluation, thermal comfort for all can only be achieved when occupants have effective control over their own thermal environment.

No full-text available

Request Full-text Paper PDF

To read the full-text of this research,
you can request a copy directly from the author.

... In this regard, engineers and designers often refer to the models proposed in the international standards (e.g., ISO and ASHRAE) to identify the borders of the thermal comfort zone. However, an overview of the history of thermal comfort research reveals that standard models such as the PMV model do not always have acceptable accuracy in all conditions [1][2][3][4]. ...
... For the first time, Humphreys in 1976 presented deviation between observed and predicted thermal sensation votes by the PMV model [1,5]. In the early 1990 s, with the completion of the empirical database sample and the variety of the required test cases for further validation of the model, bias in the PMV model was confirmed, and the criticisms were leveled at the performance of this model [1,2]. ...
... For the first time, Humphreys in 1976 presented deviation between observed and predicted thermal sensation votes by the PMV model [1,5]. In the early 1990 s, with the completion of the empirical database sample and the variety of the required test cases for further validation of the model, bias in the PMV model was confirmed, and the criticisms were leveled at the performance of this model [1,2]. Doherty and Arens [6] showed that the standard PMV model is not reliable for predicting the thermal sensation of people in hot environments. ...
Article
Adjusting clothing insulation plays a pivotal role as human behavioral adaptation to the thermal environment. Most widely used thermal comfort models, such as the PMV model, assume that the entire body is uniformly covered by clothing. Using these models in hot and humid environments, where people often wear partially covered clothing, can cause an error in predicting the thermal sensation. The object of the present paper is to investigate the effect of the assumption of whole-body uniform clothing coverage on the error of standard thermal comfort models in hot and humid environments. Investigations were performed using a three-node thermal comfort model in the temperature range of 26 C to 31 C at 50% and 70% relative humidity for three different clothing levels (0.4, 0.6, and 0.8 clo). The results showed that for typical summer clothing (0.6 clo and 80% body surface coverage), ignoring the non-uniformity of clothing insulation distribution can lead to an average of 0.2-to-0.45-unit scale deviation in thermal sensation depending on ambient temperature. This effect is more evident at higher ambient temperatures and humidity. Eventually, a new model was proposed for application in hot and humid environments by considering the non-uniformity of clothing coverage. The model’s performance was evaluated against multiple sets of reported experimental data.
... PMV représente le vote moyen déterminé à partir de la moyenne des valeurs de la TSV [25]. Il a été adopté par diverses normes nationaux et internationaux, directives et chercheurs, tels que ISO 7730 [20], ASHRAE 55 [16,19,26], et CEN CR 1752 [27]. ISO 7730 recommande de maintenir le PMV à 0 avec une tolérance de 0.5 afin d'assurer un climat intérieur confortable [20]. ...
... PMV index has been adopted by various national and international standards, guidelines and researchers, such as, ISO 7730 [20], ASHRAE 55 [16,19,26], and CEN CR 1752 [27]. ISO 7730 recommends maintaining the PMV at 0 with a tolerance of 0.5 in order to ensure a comfortable indoor climate [20]. ...
... (1.6) [27]. The PMV model suggests that the optimal thermal sensation is neutral; however, Humphrey and Hancock [124] in their study concluded that the thermal neutrality does not necessarily correspond to the preferred thermal sensation. ...
Thesis
Full-text available
The building sector is one of the largest energy end-use sectors in the world and reducing energy consumption has been the foundation of numerous research works. However, the primary objective of buildings must be to provide a comfortable environment for its occupants. Thus, it is necessary to design energy-efficient buildings so that a trade-off between energy-savings and occupants’ thermal comfort is fulfilled. Recently, glass façades have gained popularity due to their aesthetic appearance. However, they often cause occupants thermal discomfort, in addition to consuming considerable amounts of energy. In light of these conflict characteristics, the main purpose of this thesis is to understand the relationship between design parameters, thermal comfort and heating energy, in order to integrate thermal comfort in the design of energy efficient buildings. Consequently, we adopted a methodology based on the combined use of numerical simulations, Design of Experiments (DoE) technique and an optimization method. This allowed the development of meta-models of thermal comfort and heating energy. These models are then used to integrate thermal comfort in the process of building design. A desirability function was considered in order to simultaneously optimize both thermal comfort and heating energy. This trade-off helps in developing an optimal design of buildings at both energy consumption and thermal comfort levels. The proposed method is applied in a real case study. The obtained results show the added value of integrating thermal comfort in building design.
... Occupancy's thermal comfort sensation of hot or cold mainly depends on subjective parameters (metabolic rate and clothing insulation) and physical ones (mean radiant temperature, air temperature, air velocity, and relative [88]. An existing HVAC system can optimize PMV index with conventional controller, however, a fuzzy logic-based system is integrated to existing HVAC system to maintain PMV, CO 2 , and energy consumption for efficient building performance [89]. ...
... The multi-layer wall data and corresponding input and output temperatures data are obtained from Hensen's model [151]. 88 ...
Thesis
Low cost smart sensors, intelligent controllers, and IoT systems constitute key components to develop smart buildings. These smart systems produce optimal control strategies by continuous analysis of building performance. Two major parameters are controlled in the building: occupants’ comfort and heating or cooling load consumption optimization. For such intelligent controllers applications, it is essential to have building model with high performance accuracy and computational efficiency. The existing building models range from complete analytical to fully data-driven and hybrid models. The analytical model is extremely complex to model and computationally inefficient, whereas the data-driven models require a large amount of data. However, in the case of data unavailability, application of datadriven models become impossible. This work presents, hybrid modeling for heat transfer dynamics of the building using lumped parameter thermal network modeling technique. An efficient building model is developed by having proper structural knowledge of low-order model and identifying its parameter values. Simplified low-order systems are developed using 2nd order thermal network models with optimal thermal resistors and capacitors value.In order to determine the low-order model parameter values, a specific approach is proposed using a stochastic particle swarm optimization. This method provides a significant approximation of the parameters when compared to the reference model whilst allowing low-order model to achieve 40% to 50% computational efficiency than the reference analytical model.Furthermore, extensive simulations are carried out to evaluate the proposed simplified model with a more advanced complex solar gains model and identified parameters value. The developed simplified model is afterward validated with measured data from a case study building where the achieved results clearly show a high degree of accuracy compared to the actual data. Finally, an MPC controller is applied for the same case study building for thermal comfort optimization. Simulation results demonstrate the significance of the MPC controller in handling the constraints, multi-objective control, and producing optimal control strategy. The energy optimization results of the MPC have shown 31% of energy consumption reduction compared to a conventional controller.
... A common international scale called predicted mean vote (PMV) [15] was established to summarize and standardize such assessments. However, the validity of PMV is controversial [16,17], especially in East Asian regions [18]. The reported predicted accuracy of the actual votes involving several building types was 34% [17]. ...
... The reported predicted accuracy of the actual votes involving several building types was 34% [17]. Van Hoff summarized the discrepancies between PMV prediction and actual votes of the participants, showing that the preferences for the indoor environmental conditions varied individually and were dissociated from those based on the PMV model in Asian studies [16]. Differences between PMV and actual mean vote in cases of naturally ventilated and air-conditioned spaces have been reported as well. ...
Article
Full-text available
Background Indoor airflow and thermal comfort are difficult to assess through subjective evaluations because airflow sensations can differ based on various factors, such as personal characteristics, interests, preferences, and the current state of mind. Thus, subjective evaluations should be combined with objective assessments, such as physiological measurements. This study evaluated airflow and thermal comfort through physiological measurements, including skin temperature, electroencephalography, respiration, and electrocardiography, in addition to subjective evaluations. Methods Twenty participants entered a test room at 30 °C after staying in an acclimation room at 18 °C for 20 min. They were exposed to indirect and direct airflow toward their faces and performed four tasks under each condition: resting, counting to 10 s following time alerts, counting to 10 s in the mind, and mental calculation. The mean speed of the air directed to the participants’ faces was 0.123 m/s and 0.225 m/s in the indirect and direct conditions, respectively. Results The gamma and beta bands of electroencephalograms taken at the left-temporal (T3) and left-parietal (P7) sites showed significantly lower amplitudes under the indirect condition (gamma, T3: p = 0.034, P7: p = 0.030; beta, T3: p = 0.051, P7: p = 0.028). Similarly, the variability of respiration was lower under the indirect condition ( p < 0.010). The amplitudes of gamma and beta waves showed significant correlations with anxiousness levels (gamma, T3: r = 0.41; beta, T3: r = 0.35). Conclusions Our results suggest that indirect heating airflow causes lower mental stress and fatigue than those induced by direct flow, which is equivalent to more comfort. The results of this study suggest that physiological measurements can be used for the evaluation of unconscious indoor comfort, which cannot be detected by subjective evaluations alone.
... Accordingly, a PMV value of 0.85 was designated in this study as another upper limit of thermal comfort. One further practical consideration concerns the criticism for the PMV model on its inaccuracies when applied to naturally ventilated buildings in warm areas [33,35,36]. To address this for enhanced applicability of the model, an expectancy factor has thus been recommended in the literature for calculations [37]: This enables its adaptive modification to more accurately characterize local areas based on field research. ...
Article
Full-text available
Buildings and the construction sector account substantially for global energy consumption. In hot-humid areas of China, suboptimal thermal comfort in classrooms has heightened their cooling load and energy consumption. It is necessary to renovate the buildings of outdated code according to the current weather conditions to save energy. This study thus aimed to examine the thermal effects of such designs on the cooling load, based on an actual classroom building during summers in hot-humid southern China. Using air temperature and PMV values to evaluate thermal comfort, this study conducted simulation through EnergyPlus and DesignBuilder. The resultant updated typical meteorological year (TMY) and the monthly and hourly analyses of indoor thermal comfort revealed persistent classroom overheating. To mitigate the cooling load, numerous design variables were investigated: space form, roofing, external walls, windows, and shading devices. Evaluative comparisons found that appropriate choice of external windows and shading devices represented the two most effective strategies in mitigating the cooling load. Furthermore, jointly applying effective retrofit strategies to the building yielded a favorable reduction in the annual cooling energy consumption by 16.6%. The findings herein are envisioned to provide evidence-based referential guidance for building designs for classrooms in a hot-humid climate.
... Several recent key studies have shown promise in capturing individual differences in comfort preference, but there are still deficiencies to be addressed. The literature shows that conventional thermal comfort modeling approaches [1,2] that use the Predicted Mean Vote (PMV) and Predicted Percentage of Dissatisfied (PPD) have been shown to be correct only 34 percent of the time [3]. Another study shows a significant gap in delivering at least one or two factors that impact indoor environmental satisfaction [4]. ...
Preprint
Full-text available
Collecting intensive longitudinal thermal preference data from building occupants is emerging as an innovative means of characterizing the performance of buildings and the people who use them. These techniques have occupants giving subjective feedback using smartphones or smartwatches frequently over the course of days or weeks. The intention is that the data will be collected with high spatial and temporal diversity to best characterize a building and the occupant's preferences. But in reality, leaving the occupant to respond in an ad-hoc or fixed interval way creates unneeded survey fatigue and redundant data. This paper outlines a scenario-based (virtual experiment) method for optimizing data sampling using a smartwatch to achieve comparable accuracy in a personal thermal preference model with less data. This method uses BIM-extracted spatial data, and Graph Neural Network (GNN) based modeling to find regions of similar comfort preference to identify the best scenarios for triggering the occupant to give feedback. This method is compared to two baseline scenarios based on the spatial context of specific spaces and 4 x 4 m grid squares in the building using a theoretical implementation on two field-collected data sets. The results show that the proposed Build2Vec method is 18-23% more in the overall sampling quality than the spaces-based and the square-grid-based sampling methods. The Build2Vec method also has similar performance to the baselines when removing redundant occupant feedback points but with better scalability potential.
... Jedoch sei an dieser Stelle angemerkt, dass sich die meisten Arbeiten zur thermischen Behaglichkeit, die sich auf diese Modelle berufen, auf stationäre Zustände konzentrieren. So finden sie häufig Anwendung bei der Bewertung des thermischen Komforts in Innenräumen [42] und bilden aber auch die Grundlage für die wichtigsten Normen zur Bewertung des thermischen Komforts in allen Arten von geschlossenen Räumlichkeiten, in denen sich Menschen aufhalten. Obwohl die Norm ursprünglich für homogene Bedingungen entworfen wurde, wird sie in großen Teilen auf die Fahrzeugkabine angewandt und bildet die Grundlage für die häufig verwendete Norm EN ISO14505 [9] zur Bewertung des thermischen Komforts in Fahrzeugen. ...
Article
In den letzten Jahren ist ein deutlicher Anstieg in Bezug auf wissenschaftliche Untersuchungen zum Themenkomplex „komfortable und energieeffiziente Fahrzeugklimatisierung“ zu beobachten. Die Ursache für das gesteigerte Interesse ist der vermehrte Einsatz von Elektromobilität und die Weiterentwicklung des autonomen Fahrens. Für elektrisch betriebene PKWs ist eine effiziente Klimatisierung besonders wichtig, da diese die Reichweite des Fahrzeugs direkt beeinflusst. Auch beim autonomen Fahren ergeben sich in Zukunft ganz neue Anforderungen an die Fahrzeugklimatisierung und deren Integration. Aufgrund der zu erwartenden, völlig neu strukturierten Fahrzeuginnenräume werden Belüftungskonzepte benötigt, die den neuen Anforderungen an Design und Komfortempfinden gerecht werden.
... Thermal neutral is a sufficient but not a necessary condition for thermal comfort, and thermal comfort can be achieved outside the thermal neutral zone. Similar conclusions were found in former studies concerning thermal comfort in NV or MM buildings (Cao et al., 2018;Parkinson et al., 2020;van Hoof, 2008). This is also obvious in outdoor environments. ...
Article
In environments with similar physical parameters, thermal comfort and sensation feelings may differ indoors and outdoors. How indoor and outdoor thermal perception differ from each other remains unclear. This study compared and discussed 29,536 field survey data, including 19,191 sets of indoor data, and 10,345 sets of outdoor data, covering five Köppen climate zones during transitional seasons and summer. Indoor data points were collected from two databases: the ASHRAE Global Thermal Comfort II and the SCATs (Smart Controls and Thermal Comfort), while outdoor data points were collected from the RUROS database (Rediscovering the Urban Realm and Open Spaces) and five individual projects executed in Singapore, Hong Kong, Guangzhou, Changsha, and Tianjin. The concepts of neutral rate (NR) and comfort rate (CR) were developed to help categorize “neutral” and “comfort” across different studies. The results of this study show that people are less sensitive to changes in thermal environment outdoors than indoors. Moreover, thermal comfort cannot be simply treated as thermal neutral, particularly for outdoor spaces. Compared with MM (mixed-mode) and NV (naturally ventilated) spaces, outdoor space does not have the highest NR, but its CR is much higher, with a wide range of SET* (Standard Effective Temperature) corresponding to CR over 80 %, from 15.5 °C to 23.4 °C. In the Cfa (humid subtropical) climate zone, significantly higher CR are recorded for outdoor spaces, although the NR are similar or even lower than those of indoors. Natural thermal resources in the outdoor thermal environment may hold the key to extending indoor comfort ranges.
... PMV is then expressed as an index that predicts the mean value of thermal sensation votes on a sensation scale between −3 and +3, which correspond to cold and hot, respectively. PPD is an index that estimates the percentage of thermally dissatisfied people and is expressed as a function of the PMV based on an empirical relation [24]. ...
Article
Full-text available
In warm and hot climates, ceiling fans and/or air conditioners (ACs) are used to maintain thermal comfort. Ceiling fans provide air movement near the skin, which enhances the evaporation of sweat, reduces heat stress, and enhances thermal comfort. This is also called the cooling effect. However, AC usage behaviour and the effects of elevated air speed through the use of ceiling fans on indoor operative temperature during AC usage are not widely studied. This study investigated the optimum AC (cooling) set point temperature and air velocity necessary for maintaining thermal comfort while achieving energy conservation, in mixed-mode buildings in India, through field studies by using used custom-built Internet of Things (IOT) devices. In the current study, the results indicate a 79% probability that comfort conditions can be maintained by achieving a temperature drop of 3K. If this drop can be achieved, as much as possible, through passive measures, the duration of AC operation and its energy consumption are reduced, at least by 67.5 and 58.4%, respectively. During the air-conditioned period, there is a possibility that the cooing effect is reduced because of increase in operative temperature due to ceiling fan operation. Therefore, the optimum solution is to maintain the highest AC set point and minimum fan speed setting that are acceptable.
... Previous studies on thermal comfort are mostly based on Fanger's human thermal balance assessment model [10,24], however, those studies were performed under the static and conditions laboratory studies [25]. Compared with the physiological parameters of the human body, environmental parameters have always been the main factor in analyzing thermal comfort due to their advantages, like a relatively easy-to-obtain data [26]. This has led to excessive ignorance of individual differences in the process of obtaining the thermal requirements of the occupants. ...
Article
The thermal comfort in public buildings is affected by multiple psychological and physical factors. A deep understanding of these factors is necessary for intelligent ventilation control and architectural design. In this study, it was quantified the physiological and psychological parameters of the occupants in a library situated in Changsha using a questionnaire. Then, with the use of Principal Component Analysis (PCA), the dimensionality of the database was reduced. We found that the Zero-mean and unit variance projection is better than the Zero-mean projection, and 43-dimensional data can replace more than 90% of the original 61-dimensional data. Machine learning algorithms were used to analyze the results after PCA, which showed that the effect of thermal comfort on emotions is greater than that of emotions on thermal comfort. In addition, the performance of six machine learning algorithms (Linear Regression (LR), Linear Discriminant Analysis (LDA), K-Nearest Neighbors (KNN), Classification and Regression Trees (CART), Gaussian Naive Bayes (NB), and Support Vector Machine (SVM)) were compared. It is found that the predicted results of LDA were more accurate, and other algorithms showed different performances in different cases. These findings can contribute to the study of the subjective and objective feelings of indoor thermal comfort in public buildings, thereby guiding architectural design, intelligent control of ventilation systems, and realizing human-building interaction interfaces.
... However, Mui, Tsang and Wong [17] point out that the simple use of models, without due attention to the discrepancies generated between data predicted by the model and data obtained in field studies, significantly affects the implication of energy savings in thermal comfort research. Van Hoof [18] explains that the discrepancies observed might be due to the type of ventilation in the building, the small number of individuals who may have a large inter-individual distribution in thermal preferences, different climates, types of construction, age group, among others. This observation is relevant for studies on thermal comfort, as it indicates the importance of local studies to determine the best conditions for each type of indoor environment. ...
Article
Full-text available
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.
... Considering the significance of the mentioned aspects to supporting analysis and evaluations, specific mathematical models and comfort indices have been introduced and widely employed-see, for example, [19]. Focusing on thermal comfort, the Predicted Mean Vote (PMV) and the Predicted Percentage of Dissatisfied (PPD) are recognised indexes for evaluating mechanically controlled spaces [20,21]. ...
Article
Full-text available
Smart building issues are critical for current energy and comfort managing aspects in built environments. Nevertheless, the diffusion of smart monitoring solutions via user-friendly graphical interfaces is still an ongoing issue subject to the need to diffuse a smart building culture and a low-cost series of solutions. This paper proposes a new low-cost IoT sensor network, exploiting Raspberry Pi and Arduino platforms, for collecting real-time data and evaluating specific thermal comfort indicators (PMV and PPD). The overall architecture was accordingly designed, including the hardware setup, the back-end and the Android user interface. Eventually, three distinct prototyping platforms were deployed for initial testing of the general system, and we analysed the obtained results for different building typologies and seasonal periods, based on collected data and users’ preferences. This work is part of a large educational and citizen science activity.
... ISO 9920 [7] estimates the resistance of garments to dry heat loss and evaporative heat loss in steadystate conditions. However, a noteworthy finding of previous research clearly indicates that the metabolic rate is the most sensitive parameter on the PMV calculation errors among all influencing parameters of thermal comfort [8][9][10]. ...
Article
Full-text available
Thermal comfort depends on four environmental parameters such as air temperature, mean radiant temperature, air velocity and relative humidity and two personal parameters, including clothing insulation and metabolic rate. Environmental parameters can be measured via objective sensors. However, personal parameters can be merely estimated in most of the studies. Metabolic rate is one of the problematic personal parameters that affect the accuracy of thermal comfort models. International thermal comfort standards still use a conventional metabolic rate table which is tabulated according to different activity tasks. On the other hand, ISO 8996 underestimates metabolic rates, especially when the time of activity level is short and rest time is long. To this aim, this paper aims to determine metabolic rates from physical measurements of heart rate, mean skin temperature and carbon dioxide variation by means of nineteen sample activities. 21 male and 17 female subjects with different body mass indices, sex and age are used in the study. The occupants are subjected to different activity tasks while heart rate, skin temperature and carbon dioxide variation are measured via objective sensors. The results show that the metabolic rate can be estimated with a multivariable non-linear regression equation with high accuracy of 0.97.
... [7][8][9] This phenomenon is a vital factor for thermal comfort since heat transfer could affect the thermal sensation of occupants, such as feeling cooler or warmer. 10 Although the t r is not taken into account as a vital parameter in some thermal comfort studies, owing to an inadequate number of developments, [11][12][13] the importance of the t r to thermal comfort was studied in some research. 10,[14][15][16] These studies indicate that the environmental and personal parameters can be easily found by simple, low-cost sensors or constant values from tables where these are indicated in the standards expect the t r . ...
Article
Thermal comfort depends on four environmental (air velocity, relative humidity, air temperature, mean radiant temperature) and two personal (clothing insulation and metabolic rate) parameters. Among all parameters, the mean radiant temperature (tr) is the most problematic variable in thermal comfort studies due to its complexity. Measurement methods, calculation methods and assumptions are mostly used to obtain the tr. Researchers mainly prefer to obtain the tr via measurement methods or assumptions due to their easiness compared to the calculation methods. Besides, some researchers use constant values of angle factors in calculation methods. However, using constant values is not proper for every indoor environment, and it causes wrong estimations in the tr and thus the thermal comfort. This paper gives the importance of calculation of angle factors, with an example of a university office building in temperate climate zone, according to the ISO 7726. The angle factors of the room were calculated for a seated occupant from the centre of gravity in three different locations and compared with the constant angle factors. The results indicate that a significant difference (MAPE of 1.02) was found in the tr values, which were obtained by calculation of constant values of angle factors.
... This led Fanger to deduce that human thermal perception does not vary with gender (Fanger & Langkilde, 1975). Age, gender, weight, body fat, and thermal history are all factors that have been seen to influence thermal comfort levels in individuals (Lan et al., 2008;Van Hoof, 2008). ...
Article
Full-text available
Many assets that are normally installed during an energy-efficient building retrofit can also be used to provide flexible services to the electricity grid. By turning off or turning down some mechanical systems during peak times, it is possible for a building to reduce its load on the electricity network. A field demand response event was simulated at a leisure center in Ireland to evaluate the suitability of the site to participate in the Irish demand response market, to assess how much flexibility it can provide, how much the indoor conditions changed during the test, and to examine whether these remained within satisfactory limits. A survey was conducted to determine whether the occupants perceived any changes to their thermal comfort. The simulation was achieved by identifying non-critical mechanical equipment and turning them off for 2 h. A processing station for demand response and energy monitoring delivered the demand response signal to the site’s building management system. The results show that this site had a flexibility potential of 45 kW, which is considered too low to participate in the demand response market, as Irish aggregators favor sites that can offer over 250-kW flexibility. However, the indoor thermal conditions remained within reasonable ranges and the occupants did not notice the impact of the demand response event. This shows that theoretically, if smaller sites were allowed to sell their flexibility to the electricity market, such leisure centers could participate in demand response services without impacting occupants’ comfort.
... The default settings from the Rayman model [25] of a 35-year-old male of height 1.80 m, weight 75 kg, CLO level 0.4 and activity level of 80 W (light activity) were used as parameters. Mean radiant temperature (MRT), which is used in the calculations, was estimated from measured globe thermometer temperature using equation (1) [49]: ...
Article
Urban planning must consider the outdoor thermal comfort of city dwellers, particularly in cities where climate and the effects of climate change may severely influence human health and wellbeing in increasingly hot summers. The role of the urban forest in ameliorating this problem is decisive. The present study is based on a campaign of meteorological measurements in a large number of sites using a mobile data collection system to allow a human-centred approach. The aim is to quantify the different microclimates and thermal comfort conditions in six classes of urban morphology, discriminating landtypes with or without trees. In the case study of Florence, local physical characteristics of the sites; Sky View Factor (SVF), tree shade, ground surface cover, and canyon effect, can moderate human exposure to potentially uncomfortable thermal conditions during a typical Mediterranean summer. Significant differences in Universal Thermal Comfort Index (UTCI) were observed between treeless piazzas and streets and landtypes with trees or high height to width ratio (narrow alleys). Varying levels of SVF and tree cover in the sites allowed the construction of multivariate models, which revealed that, during common summer afternoon conditions, decreases of SVF by 12.5% or increases of tree cover by 25% can reduce the UTCI by 1°. Additionally, the total site factor, by incorporating temporally integrated sun exposure with the sky view factor, revealed itself a promising variable for future studies to use.
... The PMV index applies to healthy adults and cannot be used for children or persons who are elderly or disabled [16]. ...
Thesis
Full-text available
Indoor thermal comfort in residential buildings is usually achieved by tenants manually adjusting fixed temperature set-points; this is known as a ‘static’ method. Prior research has explored automated control of thermal comfort based on the concept of a Predicted Mean Vote (PMV) index, which has been developed to provide a model of perceived human comfort. However, one of the dominant contributions to this index, the Mean Radiant Temperature (MRT), effectively the mean radiant temperature of the surrounding interior surfaces, has either been: 1) inaccurately assumed to be the same as indoor air temperature; and/or 2) costly to implement due to the need for numerous additional sensors. Research is posed to leverage prior work in automatically estimating the R-values of walls and ceilings using a combination of smart WiFi thermostat, building geometry, and historical energy consumption [51] to estimate the MRT with accuracy and thus provide a means to control for comfort, rather than temperature alone. In order to assess the energy saving potential of comfort control for any residence, a machine learning model of the indoor temperature based upon a NARX Neural Network is employed. This model leverages historical thermostat and weather data to develop a means to dynamically predict the interior temperature. With a developed model, it is possible to simulate different temperature set-points on indoor temperature, and thus identify the optimal set-point temperature at all times needed to maintain a reasonable comfort condition. Application of this ideal temperature set-point for minimum human comfort to historical weather data and indoor weather conditions can yield an estimate for minimum cooling energy. The initial results showed cooling energy savings in excess of 83% and 95%, respectively, for high- and low-efficiency residences. Based on this research, it is proposed that the approach to estimate MRT can be used to calculate a more accurate PMV value and a better representation of human comfort, without anything more than a smart WiFi thermostat with readily available data. Thus, a control strategy based on this paradigm can both achieve thermal comfort in residential buildings and less energy consumption. In addition, a Model Predictive Controller (MPC) is developed to realize more realistic and sensible control. Compressor protection is also considered in the development of the controller.
... Yet, in contrast to physiological adaptations (e.g., cardiovascular, renal, endocrine) to immersion [109,113,114], thermal comfort during immersion is poorly researched. Observations on land suggest thermal comfort to be related to seasonal outdoor temperatures [115,116], humidity [117,118], and personal aspects as age [119,120], body composition and psychological factors [121], or pregnancy [122], among others. The literature also suggests gender differences in the adaption to ambient conditions [123] and non-pregnant women to prefer warmer temperatures than men [124,125]. ...
Article
Introduction WATSU (WaterShiatsu) is a treatment administered in warm water. The present study investigated if and how frequently scientifically studied application areas and effects of WATSU occur in practice, whether similar effectiveness of WATSU is observed in trials and practice, and whether practitioners can contribute additional application areas and effects of WATSU. Methods Application areas and effects of WATSU reported in a recent systematic review were extracted verbatim to be assessed in a worldwide multilingual cross section online survey, generating quantitative and qualitative data. A pre-test and retest were conducted to ensure quality and evaluate the questionnaire's psychometric properties. Results Answers of 191 respondents were processed. All proposed 26 application areas and 20 effects were confirmed, each with relatively high ratings of observed effectiveness of WATSU. WATSU was frequently applied in healthy individuals (including during pregnancy), and individuals in various pain- (e.g., low back pain, neck pain, myofascial pain, fibromyalgia) and stress-related (e.g., stress, depression, sleep disorders, fatigue, anxiety disorders) conditions. Frequently confirmed effects were physical relaxation, relief of physical tension, pain relief, increased mobility and flexibility, improved quality of life, spiritual experiences, and increased psychological health. Respondents contributed 73 additional application areas and effects (both, mental and physical) of WATSU. Conclusions Application areas and effects of WATSU are consistently employed practically and scientifically. Respondents’ ratings of effectiveness of WATSU match tentative research efforts. WATSU is cautiously recommended for the use in pain- and stress-related conditions. Short- and long-term effectiveness of WATSU need to be evaluated in high level intervention studies.
... Thermal comfort is essential for general satisfaction (Putra 2017), well-being (Al horr et al. 2016), and performance (Cui et al. 2013;Jindal 2019). Most people spend much of their time inside buildings, and hence they need a comfortable indoor temperature with little temperature fluctuation throughout the day (Ahangari and Maerefat 2019;van Hoof 2008). Achieving indoor thermal comfort becomes challenging when the interior areas include workplaces or classes, with increased concerns about user productivity and concentration (Figueiredo et al. 2017). ...
Article
Achieving indoor thermal comfort is essential for productivity, especially in educational environments, and hence has recently attracted considerable attention. Phase change materials (PCMs) integrated into various building components have been used to improve the indoor temperature. In this study, the effectiveness of integrating macro-encapsulated BioPCMs into the walls and ceilings of lecture halls in an educational building was determined via simulation. The simulations considered a hot climate coupled with controlled night ventilation of 15 air change per hour for enhancing the indoor temperature. Using the EnergyPlus software, simulations were performed for different PCM melting temperatures (25, 27 and 29°C) and thicknesses. The PCM with a melting temperature of 27°C yielded a notable reduction (0.5-3.3°C) in the indoor temperature. Furthermore, increasing the layer thickness to 3.75 cm had little effect on the temperature, as indicated by the incomplete charging process during the night.
... Este índice representa a sensação térmica média de um número significativo de indivíduos expostos, durante um determinado período de tempo e para uma taxa metabólica constante, num determinado ambiente térmico. O "voto previsto" expressa-se numa escala, sendo que o valor 0 representa o estado "neutro", de tensão mínima do corpo (ou seja, estado de conforto) fazendo a mesma atividade(Van Hoof, 2008). Este indicador varia entre muito frio (-3) e muito quente (+3).Os valores de PMV entre -0,5 e 0,5 representam uma situação confortável, pois menos de 10% da população percebe essas condições como muito quentes ou muito frias. ...
Thesis
Full-text available
In recent years, those who create strategies and policies for urban tourist destinations have been increasingly concerned with the greater or lesser capacity to enjoy public space. Furthermore, the growth of urban areas on a global scale has caused significant changes in the (micro)climate, due to the increase in impermeable surfaces, the anthropogenic heat generated by human activities and the change in air circulation. Taking into account the increasing demands of tourists and residents and the need to improve cities in the face of climate change, the option is to design new measures and action solutions. However, the lack of quality of the input data or their (total) absence, as well as their low spatial resolution, are common. The inadequacy of structures for sharing information is also noted, which significantly limits planning and adaptation actions. This investigation aims to identify the main methods of analysis to monitor the current ability to enjoy tourism based on the integration of objective and subjective domains; and contribute to the definition of action plans which seek to mitigate and adapt the tourism sector to climate change, in the medium and long-term. To assess the validity of these assumptions, the Porto Metropolitan Area, in general, and the municipality of Porto, in particular, were used as case studies. In this investigation, different methods of information and units of analysis were combined, based on a meso approach and local scale for: (i) the identification of critical areas, in an office analysis based essentially on Big Data (i.e., Flickr photographs, AirBnB accommodation and MODIS and LANDSAT satellite imagery); (ii) the assessment of the comfort level for enjoyment in critical areas with high tourist potential through field data collection; and (iii) the identification of prioritization actions and measures to maintain tourism attractiveness in view of climate change, in the medium and long-term. This research highlights the need for more detailed information, the weak interaction between stakeholders and the limitation of resources. Thus, considering that Porto is a destination with a good climate for tourism, and committed to mitigating the effects of climate change, the proposed methodological triangulation allows to outline some measures with predictable action in the short, medium and long-term. Finally, this study aims to make some contributions at national and international level, with the likelihood of the methodological approach adopted to be replicated in other geographical areas, taking into account the particularities of each territory under analysis.
... Other studies claim that the residents' ability to face heat is higher than the values provided by the Standards ASHRAE 55-2017 [36] and question their suitability [37][38][39]. There are also many discussions concerning the so-called "Thermal Neutrality" (the condition of the mind that expresses satisfaction on the whole with the temperature of the body), which point out that the thermal neutrality is not necessarily an ideal condition, since occupants may prefer the sensations of hot and cold [40][41][42][43][44][45]. ...
Article
Though a topic of wide academic debate, studies on "Low-cost" or Social Housing (SH) fail to analyze the real meaning of such habitations when taking into account remodeling and adaptations made with use, which both compromise comfort within the home and reflect on the users' health. The main objective of this study was to analyze thermal comfort in SH in a hot and humid climate, considering physical interventions (remodeling) that might impact both comfort and health needs. The study sample consisted of 99 units in which evaluations were carried out as field research (city of João Pessoa, state of Paraíba, in the Northeast region of Brazil). The results showed a great degree of discomfort (78.8% of the sample). On average, air temperatures ranged between 29.0 • C and 30.2 • C. The calculations of the Opening (OP)-confirmed the negative impact of the renovations on comfort and health, since the originally delivered housing units underwent great reductions in OP in 47.5% of the sample while 17.2% increased the OP original values. Due to the removal of window openings (45.5%), unplanned expansions often led to confined or unbearably hot environments, and the need for continuous use of fans (87.9%). The worrying post-use scenario indicates that thermal comfort losses are only felt after the physical adaptations have been made. Residents will live in unhealthy and highly uncomfortable environments and will be forced to use adaptive strategies to minimize discomfort, however, with increasing energy consumption.
... Thus, from the internal environmental conditions, several models have been developed, among them, Fanger's PMV (Predicted Mean Vote) [3]. Although this is the method most used worldwide, it is not so effective when applied to all audiences [4]. ...
Article
The Predicted Mean Vote (PMV) created by Fanger in the 70's is the most common model for estimating the thermal sensation in a group of individuals. The PMV contains some discrepancies related to the thermal reality of the environments where it is applied; thus, several researchers have developed alternative models over the past years in order to reduce these differences. This research aimed at analyzing thermal comfort conditions in Brazil by applying the PMV model and alternative models through a statistical discriminant analysis. By using the ASHRAE Global Thermal Comfort Database II, the environmental and personal variables of thermal comfort were applied in order to calculate the responses of each model and thus compare them to the responses of thermal sensation reported by people in four Brazilian cities: Brasília, Recife, Maceió and Florianópolis. The models used in this research were selected by applying the Preferred Reporting Items for Systematic Review and Meta-Analysis (PRISMA) method. A discriminant analysis was performed in order to classify people according to their thermal sensation in different groups, through the development of discriminant functions; this procedure allowed a better visualization of these groups. With the results, the discrimination of individuals was verified according to their thermal sensations, where the models were right to classify individuals into groups with 96.1% for Brasília and Recife; 99.1% for Florianópolis and 99.8% for Maceió, thus showing the effectiveness of the models.
... As noted by Van Hoof's "Forty years of Fanger's model of thermal comfort" [27], the PMV model as developed by Fanger is still the most widespread approach to estimate thermal comfort in buildings, despite some known limitations that Auffenberg et al. [28] described with reference to its practical applications to HVAC control. For example, the model is shaped on statistics over a large population, therefore it represents an average indication that often does not match individual preferences. ...
Article
Full-text available
Thermal comfort in indoor environments is perceived as an important factor for the well-being and productivity of the occupants. To practically create a comfortable environment, a combination of models, systems, and procedures must be applied. This systematic review collects recent studies proposing complete thermal-comfort-based control strategies, extracted from a scientific database for the period 2017–2021. The study consists of this paper and of a spreadsheet recording all the 166 reviewed works. After a general introduction, the content of the papers is analyzed in terms of thermal comfort models, indoor environment control strategies, and correlation between these two aspects. Practical considerations on scope, required inputs, level of readiness, and, where available, estimated cost are also given. It was found that the predicted mean vote is the preferred thermal comfort modeling approach, followed by data-driven and adaptive methods. Thermal comfort is controlled mainly through indoor temperature, although a wide range of options are explored, including the comfort-based design of building elements. The most popular field of application of advanced control strategies is office/commercial buildings with air conditioning systems, which can be explained by budget and impact considerations. The analysis showed that few works envisaging practical implementations exist that address the needs of vulnerable people. A section is, therefore, dedicated to this issue.
... It depends on the characteristics of the environment like the dry air temperature (T a ), mean radiant temperature (T r ), air velocity (V a ) and relative humidity (RH) and occupants' characteristics such as activity level (met) and level of clothing (clo). This index is the most commonly used and recognized by international standards and regulations [27,28,60], even though it overlooks factors such as climate, psychological, physiological and behavioural adaptation [86] and was developed to test on young students [4,87]. ...
Article
Full-text available
Globally, the population is ageing and extreme weather scenarios are expected, especially in southern European countries. In this context, the study assessed the thermal comfort of older people in five nursing homes in a continental Mediterranean climate in Spain during summer, through environmental measurements and surveys on site. A total of 1412 people were interviewed, including residents (older people) and non-residents (adults). The results showed that under the same environmental conditions, adults felt that the environment was warmer and they were less tolerant than older people. There was a 2.4 °C difference between the neutral temperature of older people (25.6 °C) and adults (23.2 °C). Older people were less sensitive to thermal changes and their comfort zone was wider than that of adults. The comparison with similar studies from other climatic zones concluded that the neutral temperature for elderly in different climatic zones is similar but the thermal comfort zones are different. Older people were less sensitive to temperature changes than the predicted mean vote (PMV) model predicted. Therefore, this model would not be suitable for older people in cooling conditions in the Mediterranean continental climate. These results could be a starting point for the development of more accurate, healthy indoor spaces that meet the needs of older people as a vulnerable group, while improving energy efficiency and reducing emissions.
... Several recent vital studies have shown promise in capturing individual differences in comfort preference, but there are still deficiencies to be addressed. The literature indicates that conventional thermal comfort modeling approaches [1,2] that use the Predicted Mean Vote (PMV) have been shown to be correct only 34 percent of the time [3]. Another study shows a significant gap in delivering at least one or two factors that impact indoor environmental satisfaction [4]. ...
Article
Full-text available
Collecting intensive longitudinal thermal preference data from building occupants is emerging as an innovative means of characterizing the performance of buildings and the people who use them. These techniques have occupants giving subjective feedback using smartphones or smartwatches frequently over the course of days or weeks. The intention is that the data will be collected with high spatial and temporal diversity to best characterize a building and the occupant’s preferences. But in reality, leaving the occupant to respond in an ad-hoc or fixed interval way creates unneeded survey fatigue and redundant data. This paper outlines a scenario-based (virtual experiment) method for optimizing data sampling using a smartwatch to achieve comparable accuracy in a personal thermal preference model with fewer data. This method uses BIM-extracted spatial data and Graph Neural Network-based (GNN) modeling to find regions of similar comfort preference to identify the best scenarios for triggering the occupant to give feedback. This method is compared to two baseline scenarios that use conventional zoning and a generic 4x4 square meter grid method from two field-based data sets. The results show that the proposed Build2Vec method has an 18%–23% higher overall sampling quality than the spaces-based and square-grid-based sampling methods. The Build2Vec method also performs similar to the baselines when removing redundant occupant feedback points but with better scalability potential.
... To analyze indoor environmental conditions of thermal comfort, numerous models have been developed, but the most widely used is the PMV (Predicted Mean Vote), developed by Fanger in 1970. This model is relatively efficient; thus, there is a need to develop new models [2]. ...
Article
Full-text available
The Predicted Mean Vote (PMV) has discrepancies in relation to the thermal reality of the environment; thus, adaptive models serve to improve this estimate. In this context, this research aimed to verify the performance of PMV and adaptive models under different conditions in Brazil from an analysis of variance and to further classify individuals into clusters according to their feelings of thermal comfort. Through ASHRAE’s Global II Thermal Comfort Database, users of offices and classrooms in Brasilia, Recife, Maceió, and Florianópolis were investigated. The results of ANOVA showed that the PMV model did not represent the thermal reality of any of the cities investigated, and the cluster analysis showed how most people felt thermally in relation to indoor environments.
Article
Regardless of the vehicle's application, the thermal comfort of the vehicle's occupants and driver is given increased attention. Maintaining a sense of thermal comfort, whether for safety, health or occupant thermal well-being reasons, is one of the most important goals of heating, ventilation and air conditioning (HVAC) systems. There are a significant number of physical variables that affect thermal comfort. Therefore, evaluating thermal comfort has always been a complex issue and has attracted the attention of researchers. The feeling of thermal comfort is provided by factors that depend on the heat exchange between the human body and the external environment. It is well known that one of the requirements to be fulfilled is to find a person in thermal neutrality in the environment according to the comfort equation. The article describes and evaluates the following indicators: DTS (dynamic thermal sensitivity), TS (thermal sensitivity), PMV (predicted mean voice) and PPD (predicted percentage of dissatisfaction). The most common models for evaluating thermal comfort, namely the Predicted Mean Vote (PMV), Taniguchi’s model, Zhang’s model and Nilsson’s model in a variety of car cabin conditions, have been reviewed. The limitations of these models in terms of the objectivity of the results obtained are analysed.
Article
Obtaining neural information about salivary secretory immunoglobulin E (S-IgE) is a starting point for investigating the mechanism of thermal environment regulation affecting human respiratory mucosal immunity. However, there is a scarcity of human-subjects research. To fill this void, we designed seven temperature conditions (15, 18, 21, 24, 27, 30, and 33 °C), collected electroencephalogram (EEG) and saliva from subjects, obtained thermal sensation and comfort votes, and detected S-IgE concentrations in saliva. Our results showed that the mean thermal sensation vote decreased by 2.31 units in the cold condition but increased by 2.25 units in the hot condition as compared to the thermal neutral condition (24 °C). Similarly, the absolute power of most channels in different frequency bands was the lowest at 24 °C within the thermally acceptable temperature range, including F8, F4, AF4, and T8 in α and β bands; at this temperature, the S-IgE concentration was the highest, increasing by 49.4 and 54.4%, respectively, compared to 21 and 27 °C. Furthermore, higher S-IgE concentration was associated with an increase in absolute power in the AF3 channel from the alpha band and the T8 channel from the theta band but a decrease in absolute power in the F7, T8, FC6, and F8 channels from the beta band (p < 0.05). Our findings suggest that EEG can be used to collect EEG signals associated to S-IgE concentration. Future research will concentrate on the effects of long-term temperature exposure on EEG signal and S-IgE concentration, as well as the link between them.
Article
The building industry challenges have led researchers to develop a personalized conditioning system aiming to create a microclimate comfort zone around the occupant. Radiant cooling become prevalent due to their potential in affording both comfort and energy saving. Consequently, this study investigates the performance of a personalized cooling radiant cubicle (PCRC) combined with a conventional heating, ventilation, and air-conditioning (HVAC) system in an office room in hot climates. PCRC performance is assessed by introducing a novel model that combines computational fluid dynamics (CFD) and mathematical simulation based on two criteria: the ability in creating a thermal comfort zone near the occupant at high set-point temperatures and the economic feasibility in terms of energy savings and pay-back period. The results demonstrate that PCRC (i) maintains a comfortable personal thermal environment in the desired zone (ii) reduces the thermal asymmetry (iii) improves the corresponding predicted percentage of dissatisfied (PPD) index. When compared to published experiment, it is shown that the developed model is valid with a maximum relative error of 5% underlining its accuracy and eliminating the need of a full-physics based model. Moreover, implementing PCRC reduces cooling energy by 18% compared to conventional system with a payback period between 6 and 7 years.
Article
The predicted mean vote (PMV) and its several revised models are widely used for the prediction of thermal comfort. This study aims to assess their performances using the Chinese Thermal Comfort Database (N = 41977). In air-conditioned buildings, the PMV prediction accuracy (P) and the mean absolute error (MAE) are 41.2% and 0.86, respectively, which is better than the performance in free-running buildings (P = 31.9%, MAE = 1.09). The performance of the PMV model is also tested under different HVAC modes, climate zones, and building types. The prediction accuracy varies but does not exceed 60% for all subset cases. Three typical revised models (ePMV, nPMV and aPMV) considering thermal adaptation show better accuracy than the PMV, but the improvements are still limited and do not exceed 5%. It appears that the PMV and revised models are reliable under thermal neutrality conditions, while their accuracy decreased towards the ends of the thermal sensation scale, especially on the cooler side. For further improvement of the prediction performance, it may be necessary to consider the effect of thermal adaptation in parallel with other approaches, such as revising the PMV core structure and considering individual differences.
Conference Paper
Full-text available
Due to COVID-19, people spend more and more time indoors. Healthy buildings, therefore, become more attractive to people than ever before. By summarizing specific requirements on relevant standards for healthy indoor thermal condition, this paper adopts numerical simulation and field survey to study indoor thermal comfort with a Lingnan residential building as a study case. After optimizing by building design strategy, the research results show that (1) The numerical simulation method can evaluate the indoor thermal environment, comparing the results from the field survey. (2) The study case did not meet the healthy indoor thermal environment requirements under natural ventilation. (3) By adding sunshades on windows, optimization measure is worked for healthy indoor thermal comfort. (4) Numerical simulation is used for predicting in advance. It helps the designers to solve practical problems.
Article
In recent times, global warming and climatic changes have caused significant increase in ambient temperatures, making heating, ventilation and air conditioning (HVAC) a necessity. The core purpose of HVAC is to provide comfortable environment to the occupants of a building. Central air conditioning is more reliable for easy operation with a lower maintenance cost. The main aim of this study is to design the most accurate HVAC system as per actual design requirement, for a workshop building of a power plant located in Karachi, Pakistan. HVAC systems accounts for 60% of the total electrical load requirements of a building; hence, an accurately designed HVAC system will be highly cost and energy efficient. The workshop building consists of two floors to be conditioned. All-Air variable volume system is used to design the HVAC system for the building. Two approaches are employed to achieve the objective of this study. First, cooling load temperature difference (CLTD) method and second, hourly analysis program (HAP) software. The cooling load obtained from CLTD method is 190.7 kW, equivalent to 54.25 tons of refrigeration (TR). Similarly, cooling load determined using HAP software is 195.2 kW, equivalent of 55.5 TR. The variations in cooling loads obtained from these methods are about 2% only, which is significantly lower in comparison with the available literature. This study will help engineers to design cost-effective HVAC system which is neither oversized nor undersized which will also reduce the energy consumption of building.
Article
In this study, we developed an optimised radiant-convective combined personal electric heater, considering the limitations of traditional personal heaters that heat the human body through heat transfer of single convection or single radiation. Based on human participant experiments in simulated environments, the heating performance of the optimised personal heater on the human body was tested. The initial indoor air temperature in the experimental room was set to 14 °C. Twenty-four healthy young college students, including 12 males and females, were recruited as participants. They were required to experience three types of personal heaters in a sitting position: optimised combined personal heater (PHSR + C), convective personal heater (PHSC), and radiant personal heater (PHSR). During the 80-min-long experiment, their subjective ratings of thermal comfort, perceived air quality, sweating sensation, air movement sensation, and sick building syndrome were collected using questionnaires, and physiological parameters, such as skin temperature, tympanic temperature, and heart rate, were measured. The obtained results showed that, compared with PHSC and PHSR, PHSR + C increased the overall thermal sensation more rapidly (0.083 scale/min), and maintained the human body at a warmer condition. Moreover, when using PHSR + C, mean skin temperature and its change rate, and the thermal sensation vote of all local body parts were higher. The results indicate that the heating performance of this newly developed combined personal heater surpassed that of the two traditional types. Moreover, compared to using PHSC and PHSR, over 27% of the energy consumption was saved using PHSR + C.
Article
Full-text available
The demand response (DR) program is one of the most promising components in the development of the Smart Grid. However, there are many challenges in practical operation to improve the existing and outdated system to comply with the DR programs. In Thailand, the major pain point of the office building owner in the DR program is the additional equipment, modification and operation cost of the existing equipment. Moreover, the sophisticated solution and control are other obstacles that need more measurements and data, and they make the operation difficult to work with. In this paper, we implemented a simple yet cost-effective hardware and software solution targeting an outdated air-conditioning system without voiding the warranty of the outdated equipment and without installing any additional measurements. In addition, the proposed operation is designed to be easy to operate under the equipment limitation and unskilled labor. More importantly, indoor temperature setpoint schedules during the DR event are forecasted with some public datasets to determine the capacity of the energy management system that can reduce the power consumption in the office building without an effect on the occupants’ comfort. To confirm the practicality of the proposed solution, the actual operation of the proposed solution can achieve the maximum power reduction at 19.80 kW (43.79% of the maximum power consumption) while keeping only 1 °C of difference from the typical room temperature (26–28 °C).
Article
Vertical air temperature differences (VTDs) can have important influences on thermal comfort and the evaluation of air distributions. The air distributions might create either positive or negative VTDs. However, no research has clearly revealed the effect of different directions of VTDs on human comfort. To create environments with positive and negative VTDs in this study, the air temperature of half of the body was maintained at an air temperature of 25 °C, whereas the other half of the body (the upper or lower body part, respectively) was exposed to air temperatures of 22 °C, 25 °C, 28 °C, and 31 °C, respectively. That is two series of experiments with the same VTD value but different directions were compared, based on 16 subjects seated in a climatic box in a climate chamber. The thermal sensations, sick building syndrome (SBS) symptoms, and physiological responses of occupants were studied. The results showed that subjects were more sensitive to the VTD at the upper body part in warm environments with respect to thermal sensations, perceived air quality, and sweat intensity. The analysis indicated that there were more discomfort and heat stress for positive VTDs than negative VTDs. Thus, the criterion for acceptable negative VTDs should be different with the positive VTDs incorporated in current standards. Overall, the directions of the VTDs were suggested to be considered for evaluating the thermally stratified air distributions based on both of thermal comfort and energy efficiency in buildings.
Article
Classrooms are often under‐ventilated, posing risks for airborne disease transmission as schools have reopened amidst the COVID‐19 pandemic. While technical solutions to ensure adequate air exchange are crucial, this research focuses on teachers’ perceptions and practices that may also have important implications for achieving a safe classroom environment. We report on a (pre‐pandemic) survey of 84 teachers across 11 California schools, exploring their perceptions of environmental quality in relation to monitored indoor environmental quality (IEQ) data from their classrooms. Teachers were not educated regarding mechanical ventilation. Errors in HVAC system installation and programming contributed to misunderstandings (because mechanical ventilation was often not performing as it should) and even occasionally made it possible for teachers to turn off the HVAC fan (to reduce noise). Teachers did not accurately perceive (in)sufficient ventilation; in fact, those in classrooms with poorer ventilation were more satisfied with IEQ, likely due to more temperature fluctuations when ventilation rates were higher combined with occupants’ tendency to conflate perceptions of air quality and temperature. We conclude that classroom CO2 monitoring and teacher education are vital to ensure that teachers feel safe in the classroom and empowered to protect the health of themselves and their students.
Article
Indoor cooling or heating devices are usually controlled by adult users rather than children. Preschool children, mostly younger than 6 years, have a small ability to control the thermal environment, and thus they could only rely on the assistance from their guardians to achieve thermal comfort. However, owing to the different thermal perceptions between adults and children, the parents or grandparents may create an inappropriate thermal environment for their children. To quantitatively analyze the differences between adults and preschool children regarding thermal comfort perceptions, a controlled experiment was carried out in a climate chamber. A total of 20 pairs of preschool child and parent participated in the experiment. The children's thermal perceptions are not consistent with those of their parents. The difference is more evident regarding the tolerance to a cool environment than to a warm environment. According to the experimental results, the neutral temperature for preschoolers is 20.1 °C while that for adults is 22.3 °C. The acceptable temperature range for preschoolers is 16.7–23.4 °C, while for adults it is 20.7–23.9 °C. Preschool children have a more robust tolerance to the thermal environment than adults in both subjective and physiological responses. A physical touch on the children's skin could be helpful for the parents to more precisely infer their children's thermal perceptions.
Article
In a vicious cycle, the rise of global temperatures increases demand for cooler indoor temperatures, while increased use of air conditioning leads to warmer outdoor temperatures. Most modern indoor-climate control systems aim to maintain thermal neutrality i.e., a near-constant indoor temperature, over entire spaces, if not also over time. This consumes significant resources while causing thermal discomfort for some indoor occupants. In an online study, this work explored user perceptions towards dynamic indoor temperatures, which can lead to significant resource conservation. The study included two conditions, early versus late exposure to a range-based thermostat, to assess its user acceptance, in the context of study participants’ 1) summer temperatures, 2) general temperature preferences and habits, 3) temperature-unit preference, and 4) extra-thermal factors. Due to local COVID-19 restrictions on in-person research, initial results will report on users’ behavioral intention.
Article
A preconceived notion due to past experience could influence the user perception of building facilities during the evaluation of the service gap and influence facility managers’ decisions. This paper has evaluated the effect of past experience on the perception of hostel facilities is the first of its kind. This paper tries to investigate the influence of past experience on user perception on facilities such as Visual, Thermal, Aural, Fire safety, Hygiene, and Communication. Over 234 respondents participated in the perception survey. The study computed the service gap using the SERVQUAL model, and the influence of past experience was investigated in expectation, satisfaction and service gap using the Mann–Whitney U test. The users without experience and females have shown higher expectation ratings and lower satisfaction ratings, increasing the performance gap. The past experience did not influence both the service gap and satisfaction. Past experience has shown a medium effect on Thermal and Visual aspects and a small effect on Communication. Therefore, checking the influence of past experience is not recommended during building performance evaluation. Even though, while evaluating the Thermal performance alone, the influence of past experience may be evaluated due to its dynamic nature and high energy consumption rate. Cubic regression models were used to explain the proportion of users against change in performance gap under the aspects. That can be used to benchmark similar projects.
Article
From the thermodynamic perspective, the term temperature is clearly defined for ideal physical systems: A unique temperature can be assigned to each black body via its radiation spectrum, and the temperature of an ideal gas is given by the velocity distribution of the molecules. While the indoor environment is not an ideal system, fundamental physical and chemical processes, such as diffusion, partitioning equilibria, and chemical reactions, are predictably temperature‐dependent. For example, the logarithm of reaction rate and equilibria constants are proportional to the reciprocal of the absolute temperature. It is therefore possible to have non‐linear, very steep changes in chemical phenomena over a relatively small temperature range. On the contrary, transport processes are more influenced by spatial temperature, momentum, and pressure gradients as well as by the density, porosity, and composition of indoor materials. Consequently, emergent phenomena, such as emission rates or dynamic air concentrations, can be the result of complex temperature‐dependent relationships that require a more empirical approach. Indoor environmental conditions are further influenced by the thermal comfort needs of occupants. Not only do occupants have to create thermal conditions that serve to maintain their core body temperature, which is usually accomplished by wearing appropriate clothing, but also the surroundings must be adapted so that they feel comfortable. This includes the interaction of the living space with the ambient environment, which can vary greatly by region and season. Design of houses, apartments, commercial buildings, and schools is generally utility and comfort driven, requiring an appropriate energy balance, sometimes considering ventilation but rarely including the impact of temperature on indoor contaminant levels. In our article, we start with a review of fundamental thermodynamic variables and discuss their influence on typical indoor processes. Then, we describe the heat balance of people in their thermal environment. An extensive literature study is devoted to the thermal conditions in buildings, the temperature‐dependent release of indoor pollutants from materials and their distribution in the various interior compartments as well as aspects of indoor chemistry. Finally, we assess the need to consider temperature holistically with regard to the changes to be expected as a result of global emergencies such as climate change.
Article
A data-driven probabilistic model is proposed to predict the group-level thermal satisfaction of occupants subjected to a given thermal condition. This model considers the inhomogeneous variation of inter- and intra-individual thermal sensation votes (TSVs) on the basis that individual variations in TSVs are expected to be undispersed in extreme thermal conditions and scattered in conditions closely matching thermal neutrality. Additionally, unlike conventional deterministic linear regression models, the proposed model adopts an ordinal probit regression model to treat TSVs as ordinal rather than metric variables. Model parameters are estimated by using a Bayesian inference technique to capture the stochastic characteristics of occupants' TSVs. The model's effectiveness is validated against a subset of ASHRAE Global Thermal Comfort Database II. Compared with the conventional model, the proposed model more accurately predicts the variation in TSVs and the thermal conditions in which the occupants are most satisfied.
Article
Housing construction and operating costs can be reduced if building codes are designed to meet local expectations of thermal comfort ─ expectations that can vary across cultures and climates. We analysed the energy and thermal comfort performance of 38 recently-built houses in the tropical savanna (Aw) climate of Darwin, Northern Territory, Australia with 4 to 7 star ratings according to the Nationwide House Energy Rating Scheme (NatHERS). Thermal comfort and personal adaptive behaviours of the 69 occupants were assessed using a questionnaire while, simultaneously, indoor environmental parameters were monitored. Perceptions of thermal comfort were then compared to those predicted from modelling. We found that many people were comfortable in warmer and more humid conditions than is assumed by national building codes, with many people opting for use of fans at set at high speeds instead. Large lots close to parks had the lowest use of air conditioners in the warm seasons, with very little air-conditioner use at other times.
Article
Thermal comfort is defined as “the state of mind which expresses satisfaction with the thermal environment” by the American Society of Heating Refrigerating and Air Conditioning Engineers in the standard of the ASHRAE-55. Thermal comfort is affected by six main parameters which are split into two categories; personal (basic clothing insulation value and metabolic rate) and environmental (air temperature, relative humidity, air velocity, and mean radiant temperature) parameters. The mean radiant temperature is a problematic parameter in thermal comfort studies due to its complexity. The mean radiant temperature approaches are based on different techniques such as calculation methods, measurement methods, and assumptions. Although the assumptions are utilized by researchers to abstain complexity, their accuracies are uncertain. To this aim, this study purposes to find the accuracies of calculation and assumption methods by comparing with reference measurement method. An office building in a temperate climate zone is selected as a case study. Two calculation methods and eight assumptions on obtaining mean radiant temperature are compared via in-situ measurements. The results revealed that using assumptions or calculation methods to obtain the mean radiant temperature caused a significant error compared to the reference method and researchers should consider accuracies of these methods before utilizing them in their applications.
Article
Thermal comfort is fundamental to indoor environmental design and operation as well as indoor thermal environment evaluation. This paper has reviewed the historic evolution of thermal comfort research during the last century using a systematic approach and a particular focus on adaptive thermal comfort studies. A large number of published articles as well as standards and guides were collected and screened based on a rigorous search method to ensure the literature database was both focused and complete. A further evaluation of representative prediction models has been conducted by applying the models to a large database and comparing the differences in their performance. Based on the review analysis, three representative thermal environment assessment approaches were classified as the heat balance approach, the adaptive regression-based approach and the adaptive heat balance approach. The strengths and constraints of each approach were analyzed. Comparisons of different models in the adaptive heat balance approach were conducted using the ASHRAE databases I&II. Thermal comfort theory and approaches have been developed which underpin standards and guidelines in building and engineering system design, operation and evaluation though there are pros and cons of different methods. The heat balance approach features the detailed parameters of design criteria of indoor thermal environments. The adaptive regression-based approach played an important role in raising awareness of adaptive capacities and paved the way towards first implementations into standardization. The adaptive heat balance approach combines the heat balance and the adaptive regression approaches and leads towards future improvements in adaptive comfort modelling. It demonstrates very good performance and its inclusive approach offers potential for further breakthroughs in reducing the limitations of the existing methods.
Article
The adaptive thermal heat balance (ATHB) framework introduced a method to account for the three adaptive principals, namely physiological, behavioral, and psychological adaptation, individually within existing heat balance models. This work presents a more detailed theoretical framework together with a theory‐driven empirical determination toward a new formulation of the ATHBPMV. The empirical development followed a rigor statistical process known from machine learning approaches including training, validation, and test phase and makes use of a subset (N = 57 084 records) of the ASHRAE Global Thermal Comfort Database. Results show an increased predictive performance among a wide range of outdoor climates, building types, and cooling strategies of the buildings. Furthermore, individual findings question the common believe that psychological adaptation is highest in naturally ventilated buildings. The framework offers further opportunities to include a variety of context‐related variables as well as personal characteristics into thermal prediction models, while keeping mathematical equations limited and enabling further advancements related to the understanding of influences on thermal perception.
Technical Report
Full-text available
In countries with hot climates, thermal comfort always depends on the acquired tolerance of people to the prevailing conditions, and from this stems their perceived comfort level indoors. Comfort evaluation must allow for acclimatisation if economic environmental control systems are to be specified. Previous comfort studies are critically evaluated for application to the Bangladesh climate. The most appropriate findings are summarised and considered in the context of local vernacular design and social requirements.
Article
Full-text available
This paper presents the main findings of Project HIT.2000.25 supported by the Scientific Research Foundation of Harbin Institute of Technology, a field study of indoor climates and occupant comfort in 66 residential buildings in Harbin, located in northeastern China. One hundred and twenty sets of questionnaire responses were provided from 120 subjects for winter, each accompanied by a full set of physical indoor climatic measurements with an indoor climate analyzer and a thermal comfort meter, which met ASHRAE Standard 55-1992 and ISO Standard 7726 (1985) for accuracy, duration of sample, and response time. Only 77.5% of the indoor measurements fell within the ASHRAE Standard 55-1992 and ISO Standard 7730 (1994) winter comfort zone of 16.5∼22.5°C (corresponding to the average clothing 1.37 clo); 91.7% of the occupants considered their thermal conditions acceptable. The operative temperature corresponding to the accepted thermal environment by 80% of the occupants is 18.0∼25.5°C. Thermal neutrality, according to responses on the ASHRAE seven-point sensation scale, occurred at 21.5°C in winter. The preferred temperature is 21.9°C. Over 80% of the occupants felt dry at a relative humidity of 20%∼30% in the comfort zone and over 40% at a relative humidity of 30%∼55%.
Article
Full-text available
The paper presents the results of four thermal comfort surveys conducted in naturally ventilated and air-conditioned buildings located in Bari, in Southern Italy, during winter and summer seasons. The buildings were of different types including offices, lecture rooms, and library reading rooms. The sample of subjects consisted mostly of students. A total of 20 rooms were analyzed by measuring indoor climatic parameters. During the measurements the subjects located near the probes were asked to fill in a questionnaire to rate the thermal environment at that moment. A total of 1840 valid questionnaires were collected during the four surveys. Clothing insulation levels were 0.45 clo in summer and 0.90 clo in winter. Metabolic rate was assumed equal to 1.2 met. Thermal neutrality according to the ASHRAE seven point scale occurred at 24.4°C and 26.3°C in summer, and at 20.7°C and 20.6°C in winter, respectively in NV and AC buildings. Preferred temperature, based on McIntyre preference scale, was cooler in summer (24.2°C and 25.6°C in NV and AC buildings, respectively), and warmer in winter (23.1°C and 21.2°C in NV and AC buildings, respectively). Thermal acceptability was investigated by means of all the available scales, showing that the indirect estimation of acceptability (based on the three central categories of the ASHRAE scale), only provides partial information about occupants’ conditions. Finally, the whole set of data was analyzed in order to propose an adaptive algorithm for this climatic zone. The resulting equation (Tc = 17.82 + 0.315 Trm) proved to be in good agreement with other studies.
Technical Report
Full-text available
The adaptive hypothesis predicts that contextual factors and past thermal history modify building occupants' thermal expectations and preferences. One of the predictions of the adaptive hypothesis is that people in warm climate zones prefer warmer indoor temperatures than people living in cold climate zones. This is contrary to the static assumptions underlying the current ASHRAE comfort standard 55-92. To examine the adaptive hypothesis and its implications for Standard 55-92, the ASHRAE RP-884 project assembled a quality-controlled database from thermal comfort field experiments worldwide (circa 21,000 observations from 160 buildings). Our statistical analysis examined the semantics of thermal comfort in terms of thermal sensation, acceptability, and preference, as a function of both indoor and outdoor temperature. Optimum indoor temperatures tracked both prevailing indoor and outdoor temperatures, as predicted by the adaptive hypothesis. The static predicted mean vote (PMV) model was shown to be partially adaptive by accounting for behavioral adjustments, and fully explained adaptation occurring in HVAC buildings. Occupants in naturally ventilated buildings were tolerant of a significantly wider range of temperatures, explained by a combination of both behavioral adjustment and psychological adaptation. These results formed the basis of a proposal for a variable indoor temperature standard.
Article
Full-text available
A general framework for studying affective aggression, integrating many insights from previous models (e.g., those of Baron, Berkowitz, Geen, and Zillmann), is presented. New research examining effects of extreme temperatures and photos of guns on arousal, cognition, and affect is reported. Hostile cognition was assessed using an automatic priming task (i.e., Stroop interference). Hostile affect was assessed with the State Hostility Scale. Positive and negative affect, hostile attitudes, perceived comfort, and perceived arousal were also assessed. As expected, hot and cold temperatures increased state hostility and hostile attitudes, and viewing guns did not. As expected, viewing guns primed hostile cognitions and extreme temperatures did not. Theoretical implications of these results and societal implications of the general framework are discussed.
Article
Full-text available
The indices of thermal comfort that constitute international standards, such as ISO 7730 and norms suggested by technical publications such as ASHRAE Fundamentals, are PMV, PPD, and T{sub oc}. The aim of this paper is to present similar indices developed from field studies. The studies were made at a school in Florianopolis, Brazil, and consist of more than 1,200 data points. The environmental variables were measured, and the metabolic rate and the thermal insulation of the clothing were estimated from existing tables. Thermal sensation votes were collected for all the students by means of specific questionnaires. The main conclusions are: There is good agreement between the sensations related by the subjects and those obtained from predictions determined by regression analysis; the studies provide one with a different understanding of dissatisfaction with a thermal environment; and when determined from the votes of dissatisfied people, the comfort temperature offers the advantage of showing one the percentage of people who are not comfortable.
Article
Full-text available
Present international standard for thermal comfort such as ASHRAE Standard 55 and ISO 7730 were developed to serve as a guideline for moderate thermal environments e.g. mechanically air- conditioned spaces (CEN ISO 1995). Recent thermal comfort studies had reported that some discrepancies were observed in its application for Naturally Ventilated (NV) buildings in hot and humid tropical climate (Feriadi et.al 2003). The standard failed to take into considerations tolerance and different perception of thermal comfort from different environmental setting. In this study, fuzzy logic approach is used to model an appropriate Thermal Comfort (TC) standard for tropical naturally ventilated houses. The complexities of the human cognitive process and the vagueness of linguistic expression are considered. Fuzzy logic is used as a mathematical model to allow representation of human decision and evaluation processes in algorithmic form. A detail exposition of the application which combined the linguistic approach to the optimization under multiple thermal condition criteria is presented. Some uncertainties have been identified in thermal comfort modelling. They include:
Article
Full-text available
The majority of the increasing number of older adults wishes to age-in-place. Appropriate and comfortable housing is of great importance to facilitate this desire. One of the aspects of concern is thermal comfort. This is normally assessed using the model of Fanger, however, one might ask if this model is sufficiently accurate to be used for older adults. This paper provides a short overview of the model, its applicability and implementation, and discusses aspects of the living environment that offer older adults the best possible indoor climate.
Article
Full-text available
The ability to thermoregulate typically decreases with age. This is strongly related to decreases in physical fitness and increases in the incidence of disabilities with ageing. The reduced thermoregulatory capacity leads to increased mortality and morbidity. Heat stroke, hypothermia, increased number of falls, and in home drowning are some of the problems that are identified to be associated with this reduced thermoregulatory capacity. As solution, using advanced technology in terms of full climate control is suggested as a short-term solution for the ill or infirm only. For longer-term solutions, limited climate control (taking away peak loads), improved housing design and proper use of modern clothing are proposed to alleviate the problems. For the clothing, better education of the elderly in the possible advantages of high tech clothing materials is proposed, as well as education to their proper way of use. Manufacturers should consider adjusting their marketing policies to include the elderly in their targeted groups.
Article
Full-text available
Professor Derek Croome and his colleagues in their CIB Montreal paper present the results of an investigation into the indoor environment of a naturally ventilated office and conclude that data from laboratory tests are insufficient. A field test method is established which allows an investigation to take into account window and door opening patterns and peoples reactions to air temperature, fresh air and movement. Le professeur Derek Croome et ses collègues du CIB Montréal présentent dans leur article les résultats d'une enquête sur l'environnement intérieur d'un bureau naturellement aéré. Ils conclusent que les données des épreuves de laboratoire sont insuffisantes. Un système d'essais ‘sur le terrain’ a été établi, permettant une investigation qui tient compte à l'ouverture des portes et des fenêtres, et aux réactions des occupants à la température, à la fraîcheur et aux mouvements de l'air.
Article
Full-text available
In the assessment of buildings thermal indoor climate in The Netherlands, the directives used are the ones given in 1979 and 1991 by the Government Buildings Agency (GBA). The criteria formulated in 1991 in the form of ‘weighted excess hours’ were a subject for debate. This article treats these directives and their backgrounds. Additionally, it contains information about a project started (September 2000) with as a goal to innovate these directives. This project is developed with the support of NOVEM and the GBA. On the one hand, it tries to improve and optimize the communication necessary with regards to the debates on backgrounds. On the other hand, it treats new notions about desired comfort temperature (Brager and De Dear). This focuses on the relation of the indoor comfort temperature with the outside temperature in the preceding 1 month period. The new criteria and assessment instruments will be presented in a ISSO-publication.
Article
Full-text available
Thirty-two subjects (16 male and 10 female students aged (8-25 yr) performed sedentary work in a climate chamber under two different conditions. The subject wore a light standard clothing (0.6 clo) on one occasion and a heavy clothing ensemble (1.5 clo) on the other. Each subject was exposed singly, for 2-5 hr on each occasion. During the exposures the air temperature was continuously adjusted up or down at the subject's request, as indicated on a dial voting apparatus, so that he remained in thermal comfort. Skin temperatures were measured throughout. Performance measures were obtained on a numerical addition task, a recognition memory task, and on a test of cue-utilization. Subjects rated their effort, arousal and fatigue, and the freshness of the air on semantic differential scales. No significant differences in performance could be shown between the two conditions. Subjective effort, arousal and fatigue did not differ, but subjects considered that the air was fresher in the cool air/heavy clothing condition. Skin temperatures were significantly loss uniform over the body surface in this condition, although the average skin temperature was the same under both conditions, Male subjects maintained a significantly higher mean skin temperature and a significantly higher evaporative weight loss under bath clothing conditions than did female subjects, However, there were no significant differences between the air temperatures preferred by male and female subjects. The average preferred air temperature was 23-2° and 18.7°C for 0.6 and 1.15 clo, respectively,
Article
Full-text available
Many researchers have claimed to find a link between temperature and aggression; we use U.S.A. data to confirm strong seasonal patterns in several types of violent crime. We also report seasonal patterns in U.S.A. workplace data (strikes, and quitting jobs). We suggest a medical explanation for these seasonal patterns, based on stress hormones (adrenaline, and perhaps noradrenaline and/or testosterone). The human body generates adrenaline in response to excessive heat;  adrenaline is helpful in keeping the body within safe limits, but we think that as a side effect  it leads to aggression (which is often inappropriate). We examine the shape of the curve relating temperature to aggression. Copyright © 2004 John Wiley & Sons, Ltd.
Article
Preferred room temperatures were determined for 16 male and 16 female college-age subjects who were naturally acclimatized to Singapore's year-round hot and humid equatorial climate. Each subject participated in one comfort experiment lasting two and a half hours in a climate chamber. Preferred ambient temperature was determined by adjusting the climate chamber's thermostat every 10 minutes according to the subject's wishes. The subjects were clothed in a standard uniform and remained sedentary throughout the experiment. Skin temperatures at 14 sites, evaporative weight loss, and thermal sensations were also measured. The mean of the 32 individually determined preferred temperatures at the end of the two-and-a-half-hour exposure was 25.4°C, with a between-subjects standard deviation of 1.2 K. Preferred mean skin temperature was 33.1°C and mean evaporative weight loss observed during the experiment was 21.0 g·m-2·h-1. These findings are compared with those of similar experiments conducted in colder climatic zones and with different types of subjects. Statistically insignificant differences suggest that humans cannot be naturally adapted to prefer warmer ambient temperatures.
Article
A series of experiments was carried out to study the effect of temperature and humidity on the perception of indoor air quality. The study included both laboratory and controlled field experiments using an untrained sensory panel to judge the air quality at different levels of temperature and humidity. Facial and whole-body exposure for a short term (up to 20 minutes) was used in the laboratory study, and long-term whole-body exposure (up to 4.6 hours) was used in the field study. The study found a significant impact of temperature and humidity on the perception of indoor air quality. The air was perceived as less acceptable with increasing temperature and humidity, and the acceptability decreased linearly with increasing enthalpy of the air. Ventilation requirements for comfort can be significantly reduced by decreasing indoor air enthalpy.
A postal questionnaire was completed by thirty-eight carers concerning their experiences and perspectives of the thermal comfort requirements of people with physical disabilities. The ‘stand alone’ questionnaire included sections on environmental conditions, problems and complaints, human responses and issues concerning specific disabilities. Carers were selected from those available at day centres, residential homes and holiday centres. Of the thirty-eight carers, nine were male, twenty-nine were female, four were disabled and thirty-four were not disabled. Twenty-nine of the carers (76%) thought that people with physical disabilities had different ‘temperature needs’. Of the complaints received, the most common request was for people to ask to be warmer, although the staff tended to want to be cooler. Many people with physical disabilities were affected both physically and mentally when they felt too warm or too cold.
Article
Hong Kong is a densely populated city in which the service sector dominates. The significant outdoor noise pollution and subtropical climate severely restrict the opportunity for office premises to be naturally ventilated. The high energy consumption for space cooling and the demand for improved indoor thermal comfort conditions stimulated a large-scale survey of thermal comfort conditions in Hong Kong office premises. The neutral temperatures and preferred temperatures are found to be lower than those found in other studies in the tropics, with 60% of the surveyed subjects preferring a change of the thermal conditions in summer. The outcome provides for a better notion of thermal comfort, which can be imposed on design criteria. The results also add weight to the concern about the validity in the field of the traditional chamber test data presented by ASHRAE Standard 55-1992. It further suggests the potential for adopting an adaptive control algorithm for thermal comfort.
Article
The insulation provided by seven different chairs was measured using an articulated, thermal manikin in an environmental chamber. The manikin was tested nude and while wearing several different indoor clothing ensembles. Data were collected with the manikin sitting in the different chairs and standing. Results indicated that clothing insulation decreased when the manikin was sitting (in a net chair) as opposed to standing. However, when the manikin sat in real chairs, the insulation value increased 0.1 to 0.3 clo. The amount of the increase was related to the amount of chair surface area in contact with the body. In addition, the Iclu clo values for chair insulation can be added to Iclu values for garments to determine the intrinsic insulation around a person for use in thermal comfort models.
Article
New concepts for standards on the indoor thermal environment are being proposed on the international level, with ISO (International Standard Organisation) and CEN (European Standard Organisation), and on the national level with ASHRAE (American Society of Heating, Refrigerating and Air Conditioning Engineers). Among the new developments are recommendations for acceptable thermal environments to be speci ed as classes. This allows for differences in national requirements and for buildings designs to have different quality levels. This will require, and encourage better dialog between the client (builder, owner) and the designer. There is also an ongoing discussion within the standards review committees about how people can adapt to higher indoor temperatures during summer in naturally ventilated (free running) buildings. A method for a whole year evaluation of the indoor thermal environment is also proposed.The standards will be based on requirements for general thermal comfort (PMV, Operative temperature)and local thermal discomforts (radiant temperature asymmetry, draught, vertical air temperature differences, floor surface temperatures). One critical issue is the effect of air velocity. On one hand, increased air velocity has a bene cial effect at warm temperatures, but, on the other hand, increased air velocity may result in draught sensation in cooler temperatures. Another issue is the extent to which requirements of humidity need to be included in a standard for thermal comfort. Several recent research projects dealing with adaptation, in- uence of air velocity and the effect of humidity have been the basis for increasing the usefulness and accu-racy of the standards.
Conference Paper
Proceedings of the 15th International Congress of Biometeorology and International Conference on Urban Climatology, edited by R. de Dear and J. Potter (Macquarie University; Sydney) (ISBN 1 86408 5436). pp.COMBPO2.03.1-6.
Conference Paper
In Indoor Air 2002: Proceedings of the 9th International Conference on Indoor Air Quality and Climate, Vol. 1, H Levin, ed., Indoor Air 2002, Santa Cruz, California, 2002, pp. 1032-1037
Article
Quantitative models of “thermal comfort” commonly involve prediction equations with “votes” on a thermal sensation scale as the criterion and physical variables (temperature, humidity, activity, clothing) as predictors. One established model of this sort was developed by Fanger using laboratory data. The present study sought to validate this model in realistic indoor settings by correlating predicted with measured thermal sensation judgments for 521 resident employees and students. Several demographic and cognitive variables were also measured, and direct comfort judgments were taken for comparison with the main criterion. Results provided weak support for the validity of the physical-predictor model. More important, however, was the substantial increase in predictiveness contributed by cognitive variables, and the demonstration that “comfort” defined by thermal sensation votes is not the same as that measured directly. Implications for energy conservation proposals are discussed.
Article
Designs for air conditioning systems are based on steady-state equilibrium theories of heat exchange and rely on the estimation of an average activity rate for building occupants. This is, however, an uncertain procedure. In a longitudinal field study of thermal comfort in an office building in Sydney, weightings were applied to self-reported activity rates to account for decay over the hour preceding the report. The average rate was nearly constant at 1.2met, in good agreement with other recent studies. However random individual variability may be a cause of some of the frequent complaints about thermal comfort in offices.
Article
What are the various ways in which evaluation of the several aspects of the indoor environment might combine to form an occupant's overall assessment of that environment? Data from an environmental survey of 26 offices in Europe (the Smart Controls and Thermal Comfort, or SCATs, project) are used. These show that dissatisfaction with one or more aspects of the indoor environment does not necessarily produce dissatisfaction with the environment overall. Conversely, satisfaction with one or more environmental aspect does not necessarily produce satisfaction with the total environment. Building occupants balance the good features against the bad to reach their overall assessment. Not all aspects are equally important in this subjective averaging process. Satisfaction with warmth and air quality is more important than satisfaction with the level of lighting or humidity. The relative importance of the various aspects differed from country to country, making it impossible to develop an internationally valid index to rate office environments by means of a single number. The best linear index constructed from the data failed to rank the indoor environments of the buildings in the correct order, as defined by the occupants' overall assessments. It is therefore wise to assess each of the several aspects separately rather than rely only on a combined index.
Article
Current thermal comfort research extensively documents various aspects of the human thermal response to stable environmental conditions. Reviews of recent research on outdoor comfort, however, reveals a lack of information on response to conditions in transitional spaces—those areas that are influenced by outdoor climate, yet are architecturally bounded by a building. In this work, we focused on transitional space as a space in between outdoor and indoor. Transitional spaces were organized into three categories depending on their proximity to interior spaces. Pilot measurements of physical variables were taken in six places. Transitional spaces’ physical environments varied by the space type and architectural characteristics. The typical behaviors observed were walking, standing, and sitting —different and varied compared to the sedentary behavior in offices or homes. The most efficient architectural shape of transitional spaces is related to the corresponding regional climatic condition. It was verified that PMV cannot be used for transitional space thermal comfort predictions because of its unstable and dynamic physical and MET value.
Article
This paper presents the result of a large thermal comfort survey conducted using 1520 Thai volunteers from different climatic regions of Thailand. The survey was conducted using different types of air-conditioned buildings from the private and public sectors.Apart from common thermal comfort factors such as air dry bulb temperature, relative humidity and air velocity, two non-quantifiable factors were considered. These are the acclimatization to the use of air conditioner at home and the education level, i.e., post graduate, graduate and scholar. A general database for thermal comfort studies in Thailand was created, and different thermal comfort standards were developed for the three climatic regions of Thailand. Twenty six degree Celsius and 50–60% relative humidity could be used as a comfortable environment condition for the whole country. The data was then used to generalize an earlier concept we developed for setting thermal comfort standard using data from non air-conditioned buildings.
Article
As defined by ANSI/ASHRAE Standard 55-2004, Thermal Environmental Conditions for Human Occupancy, Thermal comfort is "that condition of mind which expresses satisfaction with the thermal environment and is assessed by subjective evaluation." In the discussion that follows, I address several aspects of this definition, namely, the thermal environment itself, subjective evaluation, the condition of mind - this usually being in the domain of the psychologist and includes satisfaction, acceptance, pleasantness and the plethora of other emotional responses. Much of the material that follows is based on almost 40 years of research concerning thermal comfort.
Conference Paper
Existing specifications for thermal comfort in built environments are coming under increased criticism for failing to consider the requirements of specific populations. People with physical disabilities are an example of one such population. This paper presents the results of a study on the thermal comfort requirements of 32 people with multiple sclerosis. Subjects were exposed to three conditions: 18.5 C, PMV = {minus}1.5, slightly cool to cool; 23 C, PMV = 0, neutral; 29 C, PMV = +1.5, slightly warm to warm. Results indicate that people with multiple sclerosis have a wide range of responses to the three experimental conditions. The actual percentage dissatisfied was much higher than predicted by Fange's (1970) predicted percentage dissatisfied. Their preferred environment is slightly warmer than 23 C, PMV = 0, neutral. A subgroup of the population prefers an environment that is slightly cooler than 23 C. Further work is needed to qualify if their preferred environments match that of PMV+1 and PMV{minus}1 and to identify if any of the factors such as age, duration of disability, and medication affect the actual mean vote.
Article
This field research was aimed at clarifying the role of cognitive psychological variables in thermal comfort as measured by the ASHRAE Thermal Sensation Scale. Multiple regression analyses were carried out using two demographic variables, three physical environment measures, and eight psychological items as predictors, the idea being to establish the relative contribution of the latter to overall comfort prediction. Data for the main study were gathered in both classroom and office settings in as unobtrusive a manner as possible; a partial replication using an abbreviated survey was carried out exclusively in classrooms. Findings were consistent with those of an earlier study in showing the substantial impact of cognitive variables on Thermal Sensation judgments. Moreover, the data permitted some fairly specific conclusions regarding the identity of the cognitive systems underlying these effects. Possible implications of such information for energy conservation policies and future research are discussed. 13 references, 6 tables.
Conference Paper
Temperature and sensory indicates of human response to the thermal environment are often expressed in terms of the known response in a controlled laboratory environment, as a standard. The three rational indices of this type to be considered are ASHRAE's Standard Effective Temperature (SET*) Index, defined as the equivalent dry bulb temperature of an isothermal environment at 50% RH in which a subject, while wearing clothing standardized for activity concerned, would have the same heat stress (skin temperature T/sub sk/) and thermo-regulatory strain (skin wettedness, w) as in the actual test environment; Fanger's Predicted Mean Vote (PMV) Index, defined in terms of the heat load that would be required to restore a state of ''Comfort'' and evaluated by his Comfort Equation; and Winslow's Skin Wettedness Index of ''Thermal Discomfort'' (DISC) defined in terms of the fraction of the body surface, wet with perspiration, required to regulate body temperature by evaporative cooling.
Article
Etude mettant en évidence les différences d'isolation thermique pour un habillement donné dans différentes conditions d'environnement, ainsi que la nécessité de faire une distinction claire entre plusieurs sortes d'isolation par l'habillement, à savoir l'isolation de base, l'isolation effective, et l'isolation résultante
Article
This field study was performed during the winter of 2000–2001 in order to investigate the thermal environment and thermal comfort in residential buildings in Harbin, northeast of China. A total of 120 participants provided 120 sets of physical data and subjective questionnaires. An indoor climate analyzer and a thermal comfort meter made in Denmark were used to collect the measured parameters of the indoor environment, the predicted mean vote (PMV), and predicted percentage of dissatisfied (PPD). The conclusions are as follows: males are less sensitive to temperature variations than females; the neutral operative temperature of males is 1 °C lower than that of females; Harbin subjects are as sensitive to temperature variations as the Beijing and Tianjin subjects; the minimum value of PPD (7.5%) is similar to the Tianjin occupants; both the sensitivity and the minimum value of PPD are lower than those of the foreign field studies.
Article
Thermal comfort measurements were taken in 17 enterprises at 129 work sites in shops, stores and offices. The measurements included air temperature, air velocity, relative humidity and radiant temperature asymmetry according to ISO 7726 and ISO 7730 standards. The workers also answered a questionnaire dealing with thermal comfort. Predicted mean vote (PMV) and the percentages of workers complaining of draught (“percentage dissatisfied”, PD) were determined and compared with the workers' assessments of thermal conditions. The estimations of air temperature were always too low, and the estimated PMV indicated that the thermal environment was too warm. The calculated PMVs were usually lower than the estimated ones. Most of the workers complained of draught, even though, according to the PD index, fewer than 17% of the workers should have felt discomfort due to draught. The radiant temperature asymmetry was always small and did not explain complaints of draught on the basis of the reference value. Judged by the present reference values, and the measurement of the thermal environment, the workers overestimated the sensation of thermal discomfort.