•Measuring methods from contact manner to non-contact manner were reviewed.•The development of Euler video magnification technology was retrospected.•Skeleton keypoints model was ...retrospected.•Non-contact measurements for personalized thermal comfort were discussed.•Non-contact measurements for demand oriented HVAC systems were discussed.
Heating, ventilation and air-conditioning (HVAC) systems have been adopted to create comfortable, healthy and safe indoor environments. In the control loop, the technical feature of the human demand-oriented supply can help operate HVAC effectively. Among many technical options, real time monitoring based on feedback signals from end users has been frequently reported as a critical technology to confirm optimizing building performance. Recent studies have incorporated human thermal physiology signals and thermal comfort/discomfort status as real-time feedback signals. A series of human subject experiments used to be conducted by primarily adopting subjective questionnaire surveys in a lab-setting study, which is limited in the application for reality. With the help of advanced technologies, physiological signals have been detected, measured and processed by using multiple technical formats, such as wearable sensors. Nevertheless, they mostly require physical contacts with the skin surface in spite of the small physical dimension and compatibility with other wearable accessories, such as goggles, and intelligent bracelets. Most recently, a low cost small infrared camera has been adopted for monitoring human facial images, which could detect the facial skin temperature and blood perfusion in a contactless way. Also, according to latest pilot studies, a conventional digital camera can generate infrared images with the help of new methods, such as the Euler video magnification technology. Human thermal comfort/discomfort poses can also be detected by video methods without contacting human bodies and be analyzed by the skeleton keypoints model. In this review, new sensing technologies were summarized, their cons and pros were discussed, and extended applications for the demand-oriented ventilation were also reviewed as potential development and applications.
In recent years, adaptive thermal comfort models have been integrated into several building design and operations regulatory documents. Although the theoretical background of the adaptive thermal ...comfort models is quite mature, still some ambiguities exist for their application. The objective of this study is to identify the main sources of uncertainty around application of adaptive models and to analyze quantitatively the difference between the adaptive comfort models proposed by the regulatory documents when applied across a spectrum of different climate zones. This paper analyzes the adaptive models in ASHRAE Standard 55, the European EN 15251 (and its revision prEN 16798), the Dutch ISSO 74 and the Chinese GB/T 50785. For each regulatory document, the major variations or sources of uncertainty are investigated: for ASHRAE 55, the length of the calculation period of the prevailing mean of outdoor temperature, and for EN 15251, prEN 16798, and GB/T 50785, the exponential decay weighting factors used in the calculation of the running mean outdoor temperature.
This study shows that, although these regulatory documents have promoted the uptake of adaptive comfort models by practitioners and designers, uncertainties surrounding their application obstruct full exploitation. In response, this paper offers a fine-tuning of some of the adaptive comfort models. However, the issue of adaptive models' applicability in hybrid ventilation or mixed-mode buildings is still to be resolved, as is a rational basis for identifying the operational mode of such buildings when the adaptive models can be applied, because of their intermittent compliance during transition seasons and also extreme weather events.
► Indices for long-term evaluation of comfort conditions in building were introduced ► Such indices are described and their scope, strengths and weaknesses are highlighted ► Long-term discomfort ...indices may be used for comfort-optimization of new buildings ► They may be used for operational assessment of thermal comfort in existing buildings ► Improvement objectives are proposed for a new and reliable long-term discomfort index.
A number of metrics for assessing human thermal response to climatic conditions have been proposed in literature over the last decades. They aim at describing human thermal perception of the thermal environment to which an individual or a group of people is exposed. More recently, a new type of “discomfort index” has been proposed in scientific literature, in standards and in guidelines for describing, in a synthetic way, the long-term thermal comfort conditions in buildings and for predicting uncomfortable phenomena. Most of these new indices synthesize the thermal performance of a building in a single value.
We present in this paper a systematic review of 15 indices for the long-term evaluation of thermal comfort conditions in a building. They are here grouped in a limited number of homogenous families according to the assumptions on which they are derived and then they are analyzed according to some key aspects in order to identify their scope, their strengths and weaknesses. Finally, some guidance is provided for future developments.
•The method of combining DesignBuilder and jEplus + EA is proposed.•The best configuration form of windows and shading system is investigated.•Four-objective optimization about energy consumption and ...thermal comfort is solved.•A typical high-rise office building with large area glass is used as case study.•The research is conducted in four typical climatic regions of China.
As a large energy-consuming part of the envelope, windows and shading system play a significant role in building savings. Once established in the primary design stage, it is difficult to make changes later, especially for high-rise buildings with large areas of glass. Moreover, strongly influenced by solar radiation, the configuration of windows and shading system conflicts with each other in terms of energy consumption and indoor comfort, the optimal configuration of windows and shading system under different climatic regions has not been well solved at yet. This paper proposes an easy-operation, useful, and efficient multi-objective optimization method, using a smart optimization algorithm NSGA-II in combination with DesignBuilder energy simulation software, especially beneficial for non-programming designers. In this research, a typical high-rise office building with a large area window has been selected as a case study. Building orientation, the configuration of windows and shading system, including materials for each layer of the double-layer window, installation angle and depth of overhangs have been taken into consideration, aiming to minimize the heating, cooling, lighting energy consumption and discomfort hours, and to find the mutual relationship between each other. A set of Pareto solutions can be obtained after optimization, and the most recommended variable parameters of windows and shading system in four cities representing severe cold climate, cold climate, hot summer and cold winter climate, and hot summer and warm winter climate can be identified, respectively. Besides, Pareto optimal solutions can give designers different scheme choices based on preferences, which are of great significance to provide guidance and suggestion for designers in the early design of buildings.
In recent years, there has been a growing interest in the design of courtyards for the microclimatic enhancement of outdoor spaces. However, there is still little knowledge regarding the thermal ...performance characteristics of courtyards, particularly in hot and humid climates. This study evaluates the ability of unshaded courtyards for providing thermally comfortable outdoor spaces according to different design configurations and scenarios, including the orientations, height and albedo of wall enclosure, and use of vegetation. The software ENVI-met was used as a tool for simulating the thermal performance of courtyards in the hot and humid climate of Kuala Lumpur, Malaysia. The PMV and the number of hours per day that a courtyard could be enjoyed once the proposed design suggestions were implemented are assessed. Likewise, the Physiologically Equivalent Temperature (PET) index allowed to further explore the thermal comfort conditions of courtyards. As a result, guidelines are proposed in order to optimize the design of courtyards towards enhancing their thermal performance characteristics. In particular, the study shows that according to design parameters such as the building height ratio, an abundance in the amount vegetation the courtyard can achieve an acceptable level of thermal comfort for the tropics and may be enjoyed by its users for a long duration of daytime even during the noontime. Finally, this paper stresses that only well designed courtyards may represent a valid option for sustainable built environments.
•Outdoor thermal comfort of several unshaded courtyards are compared in a summer day in a hot and humid climate.•Both Ta and Tmrt are proven to be too high in most of the courtyards.•Maps of PMV show values above 4 for long part of the day.•Surrounding the courtyards with tall buildings is highly favorable to reduce the incoming solar radiation.•The use of trees improves the thermal comfort, whereas grass covering may increase significantly the relative humidity.
Worldwide, the residential buildings are consuming a considerable amount of energy. The high potential of buildings towards energy efficiency has drawn special attention to the passive design ...parameters. A comprehensive study on optimal passive design for residential buildings is presented in this paper. Twenty-five different climates are simulated with the aim to produce best practices to reduce building energy demands (for cooling and heating) in addition to the life-cycle cost (LCC). The occupants' adaptive thermal comfort is also improved by implementing the appropriate passive cooling strategies such as blinds and natural ventilation. In this respect, the implemented methodology is composed of four phases: building energy simulation, optimization, Multi-criteria Decision Making (MCDM), sensitivity study, and finally an adaptive comfort analysis. An optimal passive solution of the studied building indicates the potential to save up to 54%, 87% and 52% of the cooling demands (Qcool), heating demands (Qheat) and LCC respectively with respect to the initial configuration. The obtained optimal passive parameters are validated with the National Renewable Energy Laboratory NREL benchmark for low energy building's envelope. Additionally, the integrated passive cooling strategies have demonstrated its competency since it leads to a significant overheating decrease.
•Residential building's passive design parameters are optimized.•Effect of different climates of Köppen Geiger classification is studied.•Thermal comfort and energy performance of the case-studies are significantly enhanced.•Passive cooling strategies lead to adequate thermal comfort and fewer cooling systems.
Understanding occupants’ thermal sensation and comfort is essential to defining the operational settings for Heating, Ventilation and Air Conditioning (HVAC) systems in buildings. Due to the ...continuous impact of human and environmental factors, occupants’ thermal sensation and comfort level can change over time. Thus, to dynamically control the environment, thermal comfort should be monitored in real time. This paper presents a novel non-intrusive infrared thermography framework to estimate an occupant's thermal comfort level by measuring skin temperature collected from different facial regions using low-cost thermal cameras. Unlike existing methods that rely on placing sensors directly on humans for skin temperature measurement, the proposed framework is able to detect the presence of occupants, extract facial regions, measure skin temperature features, and interpret thermal comfort conditions with minimal interruption of the building occupants. The method is validated by collecting thermal comfort data from a total of twelve subjects under cooling, heating and steady-state experiments. The results demonstrate that ears, nose and cheeks are most indicative of thermal comfort and the proposed framework can be used to assess occupants’ thermal comfort with an average accuracy of 85%.
Outdoor thermal comfort could significantly affect the usage and success of urban places. Accordingly, it is recommended to be considered in both urban design and planning projects. Urbanisation has ...been recognised as a major factor in elevated daily temperature values in Australia. This study aims to investigate the past and current position of outdoor thermal comfort studies in the Australian context. A critical review is conducted to examine the quality of thermal comfort assessment in Australia's cities. Twenty-five studies were reviewed to give a precise overview of past thermal comfort studies. The review scrutinises the focus of research, methodologies applied, data collection methods and results. This review helps main stakeholders in urban development better understand the evolution of outdoor thermal comfort with respect to liveability. In this line, where possible, the shortcomings are identified, certain solutions are provided and the need for further research is highlighted. In particular, future studies are necessary to cover missing geographical regions and ethnicities that are not considered in the existing literature. Furthermore, more psychological thermal adaptation studies are necessary, especially in transient thermal conditions. Qualitative analysis is also recommended to be incorporated in further studies in addition to considering the perceived environmental quality. The study serves as a reference to researchers, urban designers and planners to enhance their knowledge for achieving outdoor thermal comfort and understanding the gaps that need to be addressed in further studies.
•Intra-urban difference in outdoor thermal comfort depends on site characteristics.•Further studies required to cover missing geographical regions and ethnicities.•Psychological thermal adaptation studies needed, including transient conditions.•Qualitative approach can evaluate urban space types and thermal adaptation.•Perceived environmental quality can be considered to assess outdoor thermal comfort.
Outdoor microclimatic conditions strongly affect the thermal comfort of pedestrians. A transversal field survey was conducted in Guangzhou, together with micrometeorological measurements. The outdoor ...physiological equivalent temperature (PET) varied from 3 to 59 °C. Regression lines were obtained to establish correlations of the mean thermal sensation vote (MTSV) with the PET bins with a width of 1 °C. Furthermore, the thermal comfort range of PET, neutral PET (NPET), and preferred PET was analyzed. The results indicated that, for the young people, thermal comfort range of PET spanned from 19.2 to 24.6 °C. The NPET and preferred PET significantly differed in different seasons. The NPET was higher in the summer than that in the winter and transitional seasons. However, the preferred PET of the summer was lower than that of the winter. The PET limits of different thermal stress categories were also confirmed, which differed from those in other cities. Thus, the impacts of adaptation on thermal comfort range were significant for people in outdoor environment.
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.
•Comprehensive literature review of the development progress of thermal comfort research.•Three representative thermal environment assessment approaches were classified.•They are the heat balance, the adaptive regression-based, and the adaptive heat balance approaches.•The adaptive heat balance approach bridges the gap of the heat balance and the adaptive regression approaches.
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