Comfort Standards Research Articles

Understanding the challenges of determining thermal comfort in vernacular dwellings: A meta-analysis

• Challenges in evaluating thermal comfort and modelling vernacular dwellings intertwine. • These entail inadequate current standards, lack of framework, and faulty modelling. • Inaccurate modelling linked to inconsistent validation, imprecise data, and software limitations. • Current comfort models must predict the possibility of adjusting their thresholds. • Creating a hygrothermal model calibration standard is key for validating vernacular heritage. The thermal comfort assessment of vernacular dwellings, as well as their inherently linked thermal dynamic modelling process, present specific challenges which remain unaddressed in the literature. The overarching purpose of this review is to identify and analyse the main methods and challenges in thermal comfort evaluation and modelling of vernacular dwellings and recommend pathways for future improvement. The main challenges found regarding thermal comfort evaluation intertwine with those of modelling vernacular dwellings. These are: i. the inadequacy of current standards; ii. the use of steady-state approaches despite evidence of their inadequacy; iii. the lack of a clear monitoring framework and insufficient occupant surveying; iv. increased uncertainty from imprecise or unfeasible in situ monitoring; v. inaccurate modelling, due to: a lack of consistent methodology and guidelines for hygrothermal model calibration; imprecise input data and; inherent software limitations in modelling vernacular elements. The main recommendations identified through this analysis include the improvement of current comfort standards and models based on further long-term field studies and the possibility of adjusting their thresholds, the development of a common monitoring framework and which parameters to focus on, and the creation of a standard on hygrothermal model calibration entailing the most adequate indexes and variables.

Motel Builders of the Modern West

Motel Builders of the Modern West

A New General Formulation for the PMV Thermal Comfort Index

The PMV index forms the basis of international thermal comfort standards. PMV was developed based on empirical relationships between the metabolic rate of activity and the body mean skin temperature and evaporative heat loss under the comfort conditions. However, many recent studies have questioned the accuracy and reliability of the PMV predictions, particularly for the discomfort range. This paper develops a general formulation of PMV that does not involve the mean skin temperature and evaporative heat loss. The new metabolic-based predicted mean vote (MPMV) index is expressed as the difference between the metabolic rate of activity and the metabolic rate required to achieve a comfort state under the imposed environment conditions. The comfort metabolic rate is found to vary linearly with the metabolic rate required to maintain the body core and mean skin temperatures at the resting thermo-neutral state. The model constants are determined using public experimental data on thermal sensation votes of young and older people. The new formulation accounts for body core cooling to achieve comfort under hot exposures; it also addresses the overlooked non-shivering thermogenesis in the body heat balance at the comfort state and covers comfort requirements for young and older people in wakeful and sleep states.

Modeling and Optimization of a Hospital Gas Turbine-Based Cogeneration System

Abstract Hospitals are among the most energy-intensive commercial buildings in the service industry. Their energy demand is characterized by specific features, being operative 24 h a day, 365 days a year. Several activities performed inside the building require strict control of the indoor climate conditions to ensure comfort and security standards. They present complex HVAC systems, needing various energy forms like electricity and heat in the form of hot water, chilled water, and steam. Consequently, hospitals are ideal applications to exploit the cogeneration systems potential. Indeed, the number of hospitals using combined heat and power (CHP) systems has grown steadily in past years. Hospitals that use CHP take advantage of favorable rate structures and protect themselves from rising electricity prices. Since CHP uses waste heat to produce thermal energy for heating and cooling, hospitals using CHP systems are more energy-efficient, leading to a reduction in the global emissions connected to the hospital activity. The present study involves the development of a numerical model of the gas turbine-based cogeneration system installed in a hospital facility. The realized model has been used to define the system management strategies that enabled two achievements. The minimization of the main global emissions parameters of the system as CO and NOx and the maximization of operational CHP parameters as total efficiency and primary energy saving (PES). The present work describes in detail the realized model and its exploitation, leading to defining the optimal system management strategy based on control parameters applicable to the real test case management system.

Standards for passenger comfort in automated vehicles: Acceleration and jerk

A prime concern for automated vehicles is motion comfort, as an uncomfortable ride may reduce acceptance of the technology amongst the general population. However, it is not clear how transient motions typical for travelling by car affect the experience of comfort. Here, we determine the relation between properties of vehicle motions (i.e., acceleration and jerk) and discomfort empirically, and we evaluate the ability of normative models to account for the data. 23 participants were placed in a moving-base driving simulator and presented sinusoidial and triangular motion pulses with various peak accelerations (Amax0.4 − 2 ms−2) and jerks (Jmax0.5 − 15 ms−3), designed to recreate typical vehicle accelerations. Participants provided discomfort judgments on absolute ‘Verbal Qualifiers’ and relative ‘Magnitude Estimates’ associated with these motions. The data show that discomfort increases with acceleration amplitude, and that the strength of this effect depends on the direction of motion. We furthermore find that higher jerks (shorter duration pulses) are considered more comfortable, and that triangular pulses are more comfortable than sinusoidal pulses. ME responses decrease (i.e., reduced discomfort) with increasing pulse duration. Evaluations of normative models of vibration and shock (ISO 2631), and perceived motion intensity provide mixed results. The vibration model could not account for the data well. Reasonable agreement between predictions and observations were found for the shock model and perceived intensity model, which emphasize the role of acceleration. We present novel statistical models that describe motion comfort as a function of acceleration, jerk, and direction. The present findings are essential to develop motion planning algorithms aimed at maximizing comfort.

Measuring the discomfort of energy vulnerable elderly people. Recommendations for solutions

Energy poverty remains today one of the most important problems for a truly just urban energy transition. In addition, older people living alone are one of the main target groups of this problem. In this research, 525 households have been monitored of which 155 were potentially in fuel poverty in the city of Valencia, Spain. In the latter, the presence in the dwelling, temperature and humidity were monitored throughout the year. We reviewed the literature and compared different comfort standards with the data collected. None of the 155 dwellings meet the comfort requirements on a regular basis. That is, their inhabitants are too often at risk to their health because of low or high temperatures and humidity. A survey was conducted to find the causes of the vulnerability of these families and to quantify their importance. In addition to the expected causes: low income, high energy prices and poor housing quality, we found elements related to habits, low energy literacy, the digital divide and others. Our findings can inform policy development for an inclusive urban energy transition that does not leave behind older people living alone.

A novel passive system for providing natural ventilation and passive cooling: Evaluating thermal comfort and building energy

Hybridization of natural ventilation with the passive cooling technique is a feasible approach for reducing the dependency on energy-consuming mechanical HVAC systems. The present study numerically investigated the viability of the application of a novel hybrid system composed of a windcatcher, an earth-to-air heat exchanger (EAHE), and a direct evaporative cooling system in a residential building. The test building was a two-story apartment with an area of 100 m2 (each floor 50 m2). 3-D Computational Fluid Dynamics (CFD) simulations were conducted to determine the airflow characteristics inside and outside the test apartment. Moreover, a computer program was developed and validated with the literature for modeling the thermal performance of the system. The effects of the environmental conditions (wind speed, ambient temperature and relative humidity, and average soil temperature) and the windows opening on the performance of the system were evaluated. The obtained results provided a design guideline that determines the allowable windows opening range for providing the thermal comfort conditions in the test rooms. The studied passive system could fulfil the comfort criteria for the test building under a maximum cooling load of 10000 W and 6500 W, according to adaptive thermal comfort standards (ATCS) and ISO7730, respectively. Finally, the energy metric and environmental analysis were carried out to compare the introduced system with the conventional mechanical cooling equipment during the hot months of the year. It was concluded that utilizing the proposed system could lessen the hourly electrical energy consumption by 0.0194 kW h/m2 compared to split air conditioners and 0.0081 kW h/m2 in comparison with evaporative coolers, resulting in a 20.2815 kg/m2 and 8.4681 kg/m2 annual reduction in CO2 emission, respectively.

Assessing Hyperloop Transport Capacity Under Moving-Block and Virtual Coupling Operations

The Hyperloop is a concept of a ground transportation system consisting of capsules traveling at very high-speeds in near-vacuum tubes. The Hyperloop aims to be a fast, cheap, and sustainable alternative to short-haul flights and high-speed rail. The small pod size requires very high frequencies to respond to future high levels of passenger and cargo demands. Media and representatives of the emerging Hyperloop industry acclaim the Hyperloop as a very capacity effective transport system, however there is no clear scientific evidence proving that. A theoretical investigation is therefore necessary to understand which capacity the Hyperloop could safely provide. This paper provides a comparative analysis of the capacity that the Hyperloop can offer for several operational scenarios and different signalling systems, including Moving-Block and the advanced concept of Virtual Coupling. Results show that Moving-Block could achieve required transport capacity levels only if pods could use high deceleration rates likely to be unsafe and uncomfortable to passengers. Virtual Coupling is instead observed to be a more satisfactory operational concept that could provide a higher transport capacity while respecting safety and comfort standards if reliable pod platooning technologies are available.

Investigation on Vibration Influence Law of Double-Shield TBM Tunnel Construction

Double-shield TBM is more efficient than shield tunnel construction in hard rock strata. It is widely used in subway tunnel construction, such as in Qingdao and Chongqing in China. However, construction vibration problems caused by double-shield TBM critically affect human comfort in surface buildings. In order to study the vibration influence law of double-shield TBM, the on-site monitoring plan of double-shield TBM is developed, relying on a tunnel section of Qingdao Metro Line 4. Then, the vibration monitoring results are analyzed, and the time domain and frequency domain characteristics of vibration acceleration are obtained. Subsequently, taking vibration peak acceleration as the research object, the transverse and longitudinal vibration laws of double-shield TBM construction are studied. Finally, according to the standard of human comfort in buildings, the vibration influence ranges of double-shield TBM construction are obtained. The research results can provide a reference for the vibration effect of double-shield TBM passing through houses, highways and bridges. Moreover, it can also provide a basis for the disputes that double-shield TBM tunnel construction affects the lives of inhabitants.

Relationship of Age, Gender, and Body Proportion to Outdoor Thermal Comfort in Open Space, Case Study: Green Park, Kitakyushu, Japan

Outdoor thermal comfort is influenced by many factors, including environmental factors and human factors. A person’s age and gender are thought to influence the survey answers. The older a person is, the lower the standard of comfort will be, and vice versa. Meanwhile, men are easier to gain thermal comfort than women. In addition, the proportion of a person’s body weight and height calculated by Body Mass Index (BMI) is also thought to affect the level of thermal comfort. The greater the distance from the proportional body, the higher the standard of comfort. These hypotheses will be scientifically proven through this research. This research was conducted for one year by quantitative methods using a printed questionnaire media. The total number of respondents was 415 people, with details of 97 people in the summer (2020), 86 people in the fall (2020), 117 people in the winter (2021), and 115 people in the spring (2021). The sampling method used a simple random sampling approach, and the questionnaire was directly distributed in Green Park, one of the urban parks in Kitakyushu, Japan. The relationship between the three variables would be analysed by the multivariate analysis method. Based on the analysis results, there is no significant correlation of age, gender, and body proportion to outdoor thermal comfort.

Impact of Artificial Lighting for Visual Comfort towards User Activity at Al-Furqon Mosque

Mosque’s primary function as a sanctuary place for Muslim communities is to accommodate large numbers of worshipers in the first place. This primary function then developed over time, requiring the mosque to be used as a place of worship and for various social activities both horizontally and vertically. Unfortunately, this development makes the initial concept of lighting supporting the atmosphere of worship facilities unable to provide visual comfort for users who use the mosque to study. This research paper aims to investigate artificial lighting designing the main room of the male worshiper at the Al-Furqon Mosque, Universitas Pendidikan Indonesia, to provide visual comfort for non-religious activities such as reading and writing. This study used a quantitative descriptive method, which explores how artificial lightning influences visual comfort. The data was collected by collecting actual data in the location, questionnaire, analysing, and interpreting them through a quantitative inductive method to determine the level of visual comfort. The result indicated that the size of the light in the room was still far below the standard of visual comfort. Furthermore, active users in the main room of male worshipers felt that the artificial lighting was inadequate for other activities, including scientific studies, tahsin and tahfidz activities (reading and memorizing Quran), mentoring, and group study.

The Effect of Lighting Intensity on Visual Comfort in The Sacred Space Of Buddhist Temple

A Buddhist temple is a sacred Buddhist space where the building users require certain visual comfort conditions. The issue is that the temple's architectural style varies according to the local context and the type of belief it teaches. Implementing certain architectural styles will affect the interior space's artificial lighting design, which eventually affects the visual comfort of building users. Therefore, this study aims to determine the effect of artificial lighting on the building user's visual comfort in two different temple case studies that use dissimilar architectural styles in Medan City, Indonesia. Two data collection methods were used in this study. The first was by measuring the room's illumination level using a handheld lux meter. Secondly, through a survey/ questionnaire to find out user's perception of visual comfort related to the usage of artificial lighting during two activities in the sacred space in the temple: praying and reciting the Sutras. As a result, the two temples were identified using almost the same principle of applying artificial lighting, which aligns with Buddhism's purpose of enlightenment, 'the journey from dark to light.' The data collection results also show similar results. Both have illumination levels below the number stated in the visual comfort standards. While on the contrary, the majority of survey respondents from both cases felt visually comfortable during their activities in the case study. This study proves that the lighting design capable of providing positive visual impacts for users can rely on the technique and method of applying lighting distribution.

Problems of Suburbanized Territories of the Irkutsk Agglomeration, on the Example of the Khomutovo Municipal Formation

The relevance of the study is determined by the problems faced by residents of suburban settlements around large cities related to daily commute and low standard of comfort living in suburban areas. In this regard, the purpose of the study is to develop a mechanism for taking into account public opinion and the requirements of urban planning documentation while improving the quality of life in suburbanized areas. We used sociological and statistical methods to adjust urban planning documentation. The study developed a strategy for the socio-economic and territorial development of the Khomutovsky municipality, conducted by the Department of Construction Economics and Real Estate Management of Baikal State University in 2021-2022. As a part of a project we carried out project-based training for undergraduates and bachelors. Also we conducted a survey of the population that revealed main problems of territories located in the suburbs of Irkutsk. The main conclusion from the study was that residents living in suburban settlements require the same level of quality of social infrastructure as city dwellers, but they pay taxes in cities where they work. This fact is a big problem for suburban municipalities because it does not allow to maintain and develop social infrastructure required by residents within the framework of the available budget revenues. The task of the administration of such suburban rural settlements is to increase the number of jobs on their territory, and, accordingly, increase tax revenues to the local budget.

Evaluation of thermal comfort in library buildings in the tropical climate of Kumasi, Ghana

Adaptive comfort considerations and passive design are crucial in tropical, hot and humid climates where the straightforward response to discomfort in this climate, such as in Ghana, has been the adoption of air conditioners and mechanical cooling. This approach, along with following the provisions of current international comfort standards, has resulted in higher electricity demand and excessive emissions of greenhouse gases into the atmosphere. This paper presents an adaptive thermal comfort field study in library buildings in the tropical Aw climate of Kumasi, Ghana considering naturally-ventilated (NV) and air-conditioned (AC) buildings. The proposed models in this study are compared with existing studies and current international standards. Using the Griffiths coefficient of 0.5, the mean neutral temperature of 27.4 °C and 30.3 °C were predicted for AC and NV mode, respectively. Although Fanger's predicted mean vote (PMV) method overestimates the extent of changes in thermal sensation votes (TSV) by indoor operative temperature in AC mode, the neutral temperature predicted from PMV (27.8 °C) is analogous to the one estimated using TSV. The adaptive equations for Kumasi's hot and humid climate predict higher slopes of 0.17 K−1 and 0.41 K−1 in AC and NV modes, respectively, than the standards; this indicates that the Ghanaian respondents were more sensitive to the outdoor temperature changes. The average difference of 2.1 °C in AC mode and 1.8–3.3 °C in NV mode were estimated when comparing the proposed model with those in the international standards

Pedestrian Wind Analysis for Indian Sub-Continent

Urbanization in India is causing local wind and climate changes near high-rise buildings, affecting the urban wind climate pedestrian-level winds to dangerous and uncomfortable levels. Hence, today's architectural planning Wind comfort has to not only consider the wind load and internal conditions, but also must consider the outdoor wind building design environment. This study reviewed the methods of evaluating pedestrian-level wind weather, different Wind tunnel test standards of wind comfort, and various techniques for evaluating pedestrian-level wind speed. In the CFD Numerical following section, a brief overview of the current research on this topic and the way forward in India is Modeling related to the design and configuration of windward buildings at the pedestrian level. After analysing the previous documents, the authors recommend it is very necessary to homogenize the various wind standards, as it might have different consequences for planers. Among the various wind tunnel experimental technologies, compared to the hot wire wind speed measurement method, the Irwin probe’s accuracy and simplicity is justified, and can be installed in multiple positions to measure wind speed horizontal of pedestrians at the same time. For the numerical simulation, several researchers have used the Renault medium Navier stokes-based technique, although the precision of this technique is not as good as the simulation of large eddies and the simulation of separate eddies. However, this technology is not only precise but also costs less due to its requirement of less computing resources.

High rise office building makeovers—Exploiting architectural and engineering factors in designing sustainable buildings in different climate zones

The high rate of urban densification has facilitated the vertical expansion of cities, with 75% of high-rise buildings designated as office buildings. To promote building energy conservation, management and sustainability, it is essential to establish during the design phase the major impactful elements on the building energy performance. Hence, this study investigates the performance-based effect of architectural and engineering elements of high-rise office buildings in different climate environments. Thereafter, the most sustainable building model was developed using the assessment results obtained from exploiting the advantages of the climate features. The results demonstrate that the building performance varies with its characteristics such as plan ratio, core position and atrium effect under different climates. While a rectangular building plan (1:1.44 plan ratio, split-core position and central atrium) presented the best performance in the warm-summer-cold-winter (WSCW) climate zone, a square building plan (with a split core and no atrium) displayed the best performance in the hot-summer-mild-winter (HSMW) climate zone. Furthermore, by exploiting the advantages of the building and climate characteristics, a mix of passive strategies was established to be suitable for attaining sustainability and comfort standards in the WSCW zone. Contrarily, active strategies are required for buildings in the HSMW zone.

Multi-body modelling and ride comfort analysis of a seated occupant under whole-body vibration

Seated occupants of any on/off-road vehicle are continuously exposed to undue low-frequency mechanical whole-body vibration (WBV) owing to the vibration conveyed from seat and backrest because occupants need to compromise with comfort and safety, leading to several musculoskeletal disorders and injuries in the body. Pain in the lumbar region is one of the most common problems that develop because of force transmitted from the backrest. Thus, consideration of backrest is highly essential while developing a biomechanical model for ride comfort analysis. For this purpose, a 20 degrees-of-freedom (dofs) biomechanical model has been proposed with a backrest to analyse cross-coupled segmental transmissibility. The interconnection between different segments of mass and backrest are modelled using eight linearized (direct as well as cross-coupled) stiffness and damping parameters. Biomechanical model parameters are estimated and optimized through a multi-objective firefly algorithm by minimizing the sum of squares error difference between analytical results and experimental segmental transmissibility published in the literature. Subsequently, ride comfort analysis is performed by integrating the proposed model with 7-dofs passenger car model. For different body segments, simulated results are obtained in terms of vertical accelerations and compared with ride comfort standards as per ISO 2631-1:1997. Additionally, a sensitivity analysis (±20% variation in mass, stiffness and damping) is performed to enhance the ride comfort of the occupant. The findings suggest that designers must focus on the pelvis, lower and upper back regions to improve the ride comfort of the occupants. The concepts and ideas outlined in this article are directly applicable in making human dummies, car suspension and seat design in the industry.

Adapting owner-occupied dwellings in the UK: lessons for the future

With 80% of the 2050 housing stock already built, the UK has at least 19 million existing homes in need of low carbon retrofit. Practice–theory-based studies have argued that these retrofits must be understood in the context of wider home adaptations and routine practices of dwelling. Therefore, changes in practices caused by the Covid-19 pandemic create a gap in the knowledge regarding the impact on home adaptations and integration of low carbon retrofit. This research compares two stages of interviews: the first undertaken in 2015–16 (30 households), investigating home adaptations and the practices of dwelling they supported. The second stage undertaken in summer 2021 (nine re-interviewees) asking participants to reflect on how their practices of dwelling had changed and how their homes had accommodated this. Rigorous line-by-line coding of the relationships between attributes of the home and practices of dwelling allows comparison between stages, offering original practice–theory-based insights into the implications for home adaptations. The findings show that practices of homeworking in particular placed great spatial and environmental pressure on the homes of growing families. If continued, these practices would create increased demand for dedicated workspaces, and significant opportunities to integrate fabric improvements and low carbon technologies into these adaptations. <em><strong>Practice relevance</strong></em> Long-term adoption of home-working practices could trigger home adaptations among households of growing families. Analysis of pre-pandemic adaptations to support homeworking suggests, first, this is likely to manifest in loft conversions; and second, these present a significant opportunity to integrate renewable energy in the form of solar panels. Furthermore, higher rates of homeworking have facilitated a stronger appreciation by owner-occupiers of the benefits of energy efficiency measures in creating normative standards of comfort that support practices of dwelling. These findings are significant for practice because they identify the opportunity that home adaptations to accommodate altered practices of dwelling present to integrate low carbon retrofit technologies into these homes. This will require action from policymakers and industry to increase practical understandings of these technologies among owner-occupiers; increase the availability of specialist installers; and implement appropriate regulations and financial procedures to support the integration of low carbon technologies into practices of home adaptation.

Comfort limit for asymmetric thermal radiation from a cold wall in neutral to cool environments

Asymmetric thermal radiation from a cold surface, could easily cause local thermal discomfort and even health problems, such as knee osteoarthritis. An experiment with subjects was conducted to study the radiant asymmetry caused by a cold wall at a room temperature of 18 °C, which is the lower limit of the room temperature for heating design in Chinese Building Regulations. The temperature of a single wall was set at 15 °C and 12 °C respectively to simulate a cold exterior wall or window. A control experiment was also conducted under uniform chamber conditions. Groups of 24 healthy college students participated in the experiments. During the first 30 min of the 90-min experiment, the participants could adjust their clothing to approach thermal comfort. The skin temperatures and thermal perceptions of the subjects were measured. The results indicated that clo-value for participants increased with the decrease of the temperature of the cold wall. The skin temperatures and thermal sensations of the limbs were significantly lower than these of the upper torso. The skin temperature of the calf was the lowest. The prolonged exposure to the cold wall decreased the acceptability of the subjects. Accepting 5% of the subjects expressed local discomfort, the acceptable radiant temperature asymmetry was 4.2 K. The limit value obtained in this experiment was significantly lower than the limit value recommended in the existing standards. The lower acceptable value of radiant temperature asymmetry from this study can provide a relevant input to a revision of existing thermal comfort standards.

Understanding thermal comfort in vernacular dwellings in Alentejo, Portugal: A mixed-methods adaptive comfort approach

While a significant body of literature has been published on thermal comfort in dwellings, the particular challenge presented by vernacular dwellings in striking a balance between improving thermal comfort, energy savings, and heritage conservation has not been adequately investigated. The occupants’ way of life, embodying regional cultural practices and traditional adaptive behaviours, and their unique thermal expectations, impact thermal comfort perception but are largely ignored in current comfort standards. This paper addresses this gap by evaluating the thermal comfort of vernacular dwellings in Alentejo, Portugal, based on the Portuguese context-adapted thermal comfort model (PTC). The work also attempts to assess the suitability of thermal comfort adaptive and steady-state methods by undertaking a comparative analysis with the PTC model results. Key findings include the broad summer thermal acceptability in the vernacular dwellings, exceeding that of regular dwellings and thermal comfort standards, and the significant winter underheating, which highlights that priority should be given to improving cold-related risks. The PTC model was found to accurately represent summer thermal comfort conditions in naturally-conditioned vernacular dwellings in Alentejo, albeit underestimating underheated hours and requiring nighttime and boundaries adjustments to improve its accuracy. The methods detailed under EN 16798 and REH (Regulamento dos Edifícios de Habitação/Regulation of Energy Performance of Residential Buildings) are deemed unfit to evaluate thermal comfort in vernacular dwellings, especially in summer.