Lack Of Thermal Comfort Research Articles

Construction parameters that affect the air leaks of the envelope in dwellings in Madrid

In buildings, ventilation, or rather, a lack of airtightness facilitates air leaks, from the outside to the inside and vice versa, and is not controlled. Cold air enters through the enclosure, and warm air is lost to the outdoors, due to the poor hermeticity of the facades, roofs, carpentry, ducts, etc. In order to quantify the airtightness in multi-family dwellings in Madrid, 151 blower door tests have been carried out in multi-family dwellings built in different periods whose execution has been regulated by the UNE-EN 13829 standard. Through its quantification by an n50 value, the average values of 5.8 renovations per hour have been obtained in addition to detecting the main points where air infiltration occurs. The constant improvement in the transmittance of construction elements has indicated that the entry of outside air has a progressively greater relevance to the total energy consumed by the residential sector while facilitating the uncontrolled movement of air through the building envelope. This not only implies higher energy consumption but also generates a series of problems that affect the health of the occupants, such as a lack of thermal comfort, entry of pollutants and odours, noise, inadequate operation of ventilation systems, and less protection against fire.

Effect of green infrastructures supported by adaptative solar shading systems on livability in open spaces

Lack of thermal comfort in the existing building stock in many warm summer climates and the COVID-19 pandemic have increased residents' temporary occupation of urban open spaces. However, climate change and other effects such as urban heat islands are also negatively affecting the livability of these spaces. Therefore, strategies are needed to improve the thermal conditions in these areas. In this context, the research designs, simulates and assesses an urban green infrastructure supported by an adaptative solar shading system. For this purpose, a public square to be renovated in Seville (Spain) is chosen. After an analysis of the current situation, more vegetation is added. However, trees are not planted fully grown, so their cover is not enough in the short term and an artificial system that protects from the sun by casting shade and that adapts to both their growth and the seasons is included. The urban space is characterized by on-site measurements, proposing four (initial, intermediates and final) scenarios using computational fluid dynamics simulations in an holistic microclimate modelling system. In turn, changes in thermal comfort are analyzed using the COMFA model. Results show that the air and surface temperature are decreased, reducing the number of hours in discomfort by 21% thanks to incorporating the green structure and by 30% due to the vegetation. It can be concluded that the use of these temporary urban prostheses enables urban spaces regenerated with vegetation to be enjoyed without waiting 20 or 30 years for the trees to mature, encouraging people to spend more time outdoors from the start of the intervention.

Assessment of Thermal Comfort in Rooms Equipped with a Decentralised Façade Ventilation Unit

Thermal comfort affects not only the well-being of the occupants of a building but also the effectiveness of their learning and work efficiency. It can be disturbed if the ventilation airflow is increased when improving indoor air quality. When natural ventilation is used in the fall and winter period, the supply air temperature is low, resulting in a lack of thermal comfort. In existing buildings, there is often no place for mechanical ventilation; hence, decentralised façade ventilation units are increasingly used. The article presents an analysis of thermal comfort in rooms with this type of unit equipped with heat recovery exchangers of different efficiencies. Studies have shown that the alternating supply/exhaust airflow and the related unevenness of air streams flowing through the heat accumulator cause an inflow of low-temperature air, resulting in thermal discomfort. The highest value of the PMV index was −1.6, and the lowest was −4.1, which means that 54.8 to 100% of the occupants are dissatisfied with their thermal comfort. This means there is a need to change the construction of inlet/exhaust vents so that the stream of supply air is not directly parallel to the floor. In addition, the use of an air heater should be considered.

Thermal comfort and transition from solid fuel heating in historical multifamily buildings — Real-world study in Poland

Providing thermal comfort in residential buildings in winter by solid fuel combustion is a significant source of emissions that contribute to air pollution and climate change. In this field study, we investigated thermal comfort in tenements (16 apartments) equipped with heating systems prevalent in Polish urban historical buildings, i.e. solid fuel stoves, electric heating, district-supplied central heating, or individual gas boilers. Our research comprised spot check multi-parameter measurements and continuous monitoring of the thermal environment, together with a longitudinal thermal comfort questionnaire survey (N = 0.2539). Differences were detected in the thermal environments depending on the heating system. In our sample solid fuel heating was associated with a thermal environment on average 3.3 °C colder than those heated by gas central heating. The inferiority of thermal comfort conditions associated with solid fuel was shown by predicted mean vote and adaptive thermal comfort analyses. However, the survey results on individual thermal sensations and preferences did not confirm these findings. Therefore, activating the residents to expedite the transition from solid fuel heating might not be supported effectively by the “lack of thermal comfort” narrative. Accordingly, we identified a need for further studies investigating the link between domestic thermal comfort and satisfaction with control over the cost of heating.

Energy poverty, occupant comfort, and wellbeing in internally displaced people’s residences in Sri Lanka

Internally displaced people (IDP) due to conflict and violence were estimated as 41.3 million in 55 countries as the end of the year 2019, the highest figure ever recorded. Sri Lanka has not yet prioritized the health and wellbeing of households in building designing, with the emerging heat island effect making the lives more desperate for IDP. This study focused on the effect of energy poverty on occupant comfort in determining the quality of life of people and adaptive behaviors to manage heat strain in overheated interiors of rehabilitated residences in Jaffna, Sri Lanka. Field investigations consisted of personal monitoring, questionnaire surveying and physical measurements in four clusters of rehabilitation residence programmes in four regions. The study found that IDP were suffering from hidden energy poverty, with mean electricity consumption of 52 kWh per household per month. Residents have marginal (29%) access to clean fuels for cooking and accountable for an abnormal particulate matter count of 360 951 particles per cubic centimeter. Findings explicitly revealed the presence of overheated spaces with mean thermal preference of −0.6 conveying the need of cooler indoor environment. People tend to exhibit behavioral adjustments to cope up with prevailing extreme temperatures. Severity of heat stress informed by modified wet bulb globe temperature (WBGT) reporting 90% (28–31 °C) of households facing higher risk of heat strain while remaining 10% (>31 °C) are in hazardous situation. Predicted mean vote (PMV) was 1.29 explains warm sensation with predicted percentage of dissatisfied (PPD) 44.1% not complying to ASHRAE 55 standards. This detrimental combination of fuel poverty, lack of thermal comfort, and unacceptable indoor air quality has been a significant factor for 62% of the residences reporting at least one type of illness and being more prone to cardiovascular and respiratory disorders (37%). Thus, the study evidenced the presence of energy poverty and overheated interiors in the IDP's residences in hot tropics of Sri Lanka.

HEAT - Human Embodied Autonomous Thermostat

The lack of thermal comfort among occupants is a common problem in built environments. Recent studies have investigated various physiological sensing and modeling approaches and demonstrated more robust thermal comfort prediction than the Predicted Mean Vote and participatory sensing methods. However, such physiological sensing approaches only work with iterative and passive Heating, Ventilation, and Air Conditioning (HVAC) control schemas which can lead to problems including uncertainties in setpoint control outcomes and interruptions to building occupants. To address this critical limitation, this paper proposes a new paradigm named Human Embodied Autonomous Thermostat (HEAT) that considers human occupants as an embodiment of smart and connected thermostats where physiological measurements in form of facial skin temperature can be used to directly communicate with and control HVAC operations for improved thermal satisfaction and reduced energy use while maintaining comfort in multi-occupancy spaces. This paradigm leverages occupants' skin temperature responses under different thermal environments and integrates two types of personal models - thermal comfort model and physiological predictive model to determine occupants’ comfort, which can be represented as the thermal comfort zone and comfort probability. Based on these two metrics, three HVAC strategies are compared to demonstrate thermal comfort optimization for a group of occupants. The result suggests different setpoint options as a trade-off between overall comfort and energy use. The proposed HEAT framework can conceptually make wall-mounted physical thermostats redundant by serving as a basis for automated environment control based directly on human measurements to improve personalized human experience, well-being, and building energy efficiency.

Robust non-intrusive interpretation of occupant thermal comfort in built environments with low-cost networked thermal cameras

About 40% of the energy produced globally is consumed within buildings, primarily for providing occupants with comfortable work and living spaces. However, despite the significant impacts of such energy consumption on the environment, the lack of thermal comfort among occupants is a common problem that can lead to health complications and reduced productivity. To address this problem, it is particularly important to understand occupants’ thermal comfort in real-time to dynamically control the environment. This study investigates an infrared thermal camera network to extract skin temperature features and predict occupants’ thermal preferences at flexible distances and angles. This study distinguishes from existing methods in two ways: (1) the proposed method is a non-intrusive data collection approach which does not require human participation or personal devices; (2) it uses low-cost thermal cameras and RGB-D sensors which can be rapidly reconfigured to adapt to various settings and has little or no hardware infrastructure dependency. The proposed camera network is verified using the facial skin temperature collected from 16 subjects in a multi-occupancy experiment. The results show that all 16 subjects observed a statistically higher skin temperature as the room temperature increases. The variations in skin temperature also correspond to the distinct comfort states reported by the subjects. The post-experiment evaluation suggests that the networked thermal cameras have a minimal interruption of building occupants. The proposed approach demonstrates the potential to transition the human physiological data collection from an intrusive and wearable device-based approach to a truly non-intrusive and scalable approach.

The special clothing for firefighters – the normative requirements and original research results

The firefighters work in extreme environmental conditions and have to solve a wide variety of problems during their work. These can be rescuing and firefighting actions or removing effects of accidents or natural disasters. In order to protect, not only others but also themselves, they must be focused as much as possible in order to avoid mistakes. Optimal conditions for such work could create so-called thermal comfort, characterized by a thermoneutral state of a body. Lack of thermal comfort can also cause an increased number of mistakes. That is why it is so important to select the right protection and to know the impact of the protective clothing (special clothing) on the thermal sensation of firefighters. This article presents the requirements for special clothing for firefighters, the results of thermal insulation tests of the above-mentioned clothing and the analysis of thermal sensations of its users (by PMV index).

WITHDRAWN: Assessment of an algorithm involving building thermal mass, indoor and outdoor mean running temperatures to enhance the control of night ventilation

Abstract The aim of the present work is to improve night ventilation control strategy, especially for the mid-season periods where an unadapted control scheme can result in significantly undesirable heat loads or either in a lack of thermal comfort that may be due to high variations in climate conditions. It concerns mainly buildings where the indoor air is conditioned all the year like commercial buildings or offices. An algorithm is developed and handled to control night ventilation for different kinds of buildings presenting different thermal masses. Two variables are calculated at every time step: the sliding average of outdoor and indoor temperatures. Also three features are required to be set to adapt the algorithm to the building and its environmental conditions: a coefficient related to the building time constant and two selected set-point temperatures that are respectively compared to the outdoor and indoor sliding average temperatures for every time step. The two selected set-point temperatures are specified with a parametric study realized on the building such that they minimizes the discomfort period, the heating load and the fan electric power. The confrontation of the adaptive night ventilation and the classic night ventilation was achieved showing that besides feasible energy savings (up to 30%) and about 57% less discomfort hours, the algorithm was effectively able to identify with accuracy the periods where the night ventilation should be activated in the building and the periods where it shouldn't, thus limiting drastically concomitant night ventilation and diurnal heating load hours. The effectiveness of the algorithm was also shown in its capacity of reducing the electric power demand of the fan by a factor of 2. Results show that the adaptive algorithm was able to adapt to the mid-season period thus preventing unwanted heat and fan electric loads while preserving very good thermal comfort conditions.

Daily electricity consumption profiles from smart meters - Proxies of behavior for space heating and cooling

Daily electricity consumption profiles from smart meters are explored as proxies of active behavior regarding space heating and cooling. The influence of the environment air temperature (multiple maximum and minimum daily thresholds) on electricity consumption was explored for a final sample of 19 households located in southwestern Europe (characterized by hot, dry summers and cool, wet winters), taking the full year of 2014. Statistical analysis of the deviations from hourly average electricity consumptions for each temperature thresholds was performed for each household. Firstly, these deviations could act as proxies highlighting possible lack of thermal comfort on space cooling, and partially on space heating, supported by door-to-door survey data, on socio-economic details of occupants, buildings bearing structure and equipment's ownership and use. Secondly, meaningful differences of consumers' behavior on electricity consumption pattern were identified as a response for space heating and cooling to the environment air temperatures thresholds. Additionally, statistical clusters of active and non-active behavior groups of households were assessed, showing the electricity use for space heating. This paper illustrates the importance of the widespread use of smart-meters data on the increasingly electrified buildings sector, to understand whether and how thermal comfort could be achieved through active climatization behavior of its occupants. This is particularly important in regions where automatic HVAC systems are almost absent.

Comparison of thermal comfort conditions in multi-storey timber frame and cross-laminated residential buildings

In recent years, timber construction systems have been increasingly used in multi-storey residential construction in Europe. In line with this international trend is the choice of the Trentino social housing company ITEA to build two five-storey multi-family apartment buildings in Trento (Italy) using two different timber wall systems. The two buildings are identical except for their structural system: timber frame (TF) and cross laminated timber (CLT). The design and the construction of these two buildings are the result of an international collaboration between ITEA and the Canadian social housing company Quebec Societe D’Habitation in order to evaluate and compare timber construction systems for social housing from the two countries. Since the two buildings have identical floor plans, layouts and finishes and differ only in their structural system, they present a unique opportunity for comparison of the two key forms of timber construction in terms of economic, engineering and indoor comfort issues. This paper investigates the difference in indoor conditions and analyse the achieved thermal comfort by measuring physical parameters and surveying the occupants’ perception. The two structural systems used for the buildings represent two widely used but fundamentally different forms of timber construction. The light timber frame is extremely lightweight, which gives the building low thermal mass and consequently low thermal inertia. This can lead to a lack of thermal comfort, particularly in summer, due to temperature fluctuations. Cross-laminated timber, used to form the timber shear walls in the south building, is a comparatively modern building component. Again, it can be highly prefabricated, and used with computer controlled cutting techniques to pre-cut openings for windows, doors and services to a high degree of accuracy. This system, known as ‘massive timber’, provides a higher thermal mass, if compared to the previous system. By means of indoor comfort monitoring and subjective questionnaires to the users’, it has been investigated to what extent this difference of thermal properties affects the indoor conditions provided and the final users’ satisfaction towards the thermal environment. This experimental campaign falls into a broader policy adopted by ITEA to engage closely with the performance of the buildings they build and manage, in accordance with an increasing interest globally in building performance assessment and post-occupancy evaluation (POE), whose main purpose is to investigate occupants’ reported levels of comfort and satisfaction and the degree to which they perceive their needs are being met by the building’s indoor conditions.DOI: http://dx.doi.org/10.5755/j01.sace.19.2.17531

Global comfort and indoor environment quality attributes for workers of a hypermarket in Southern Italy

The paper investigates the interactions between global satisfaction for workers in hypermarkets and the different attributes that contribute to it. Thermal, acoustical, visual, and air quality conditions were investigated through both subjective and objective measures carried out in a hypermarket in Southern Italy. Questionnaires were collected over a two-years time span. Simultaneously, measurements of the main objective descriptors of indoor quality were carried out. The study took advantage of different statistical techniques, including factor analysis, multiple linear regression analysis, and nonlinear methods based on Kano's satisfaction model. Factor analysis pointed out the existence of two main groups of dissatisfied. The first one gave greater relevance to visual, and acoustic aspects while being neutral towards thermal aspects. Conversely, the second group was more influenced by lack of thermal comfort and presence of local discomfort, while showing indifference towards visual and acoustic aspects. Application of Kano's model showed that thermal local discomfort and IAQ were considered “basic” aspects (i.e. they have negative effect on global satisfaction when they underperform), while acoustic comfort was considered a “bonus” aspect, capable to improve overall rating when it performed well. Visual and thermal comfort, had a mostly linear influence on global satisfaction but also proved to have the highest impact.

Optimization of multifunction multi-source solar systems by design of experiments

Abstract Simulation based optimization may use parametric runs or optimization techniques. We propose a hydraulic schematic for a multifunction multi-source solar system (MFMSYS) and we consider the area of the solar collector and the volume of the thermal storage tank as the parameters to be optimally sized for minimizing the total cost. An additional cost, which increases exponentially with the lack of thermal comfort, is introduced in the total cost function. The sizing is then an optimization without constraints problem. The running costs are estimated by dynamic simulation of the building and its associated solar system. The total cost function has a valley-like shape oriented almost along the volume of the storage tank. Consequently, the total cost is very little sensitive to changes in the volume of the storage tank. Although optimization techniques, such as Generalized Pattern Search–Particle Swarm Optimization (GPS–PSO) hybrid algorithm prove to correctly find the optimum set of parameters, they do not give information about the valley shape of the cost function around its minimum value. We adapted an optimization technique based on the Design of Experiments (DOE) to the sizing by simulation of MFMSYS. The method proves to be faster than GPS–PSO and gives the approximated shape of the cost function around the optimum point. The Hessian of this approximated cost function indicates the valley-shape form and allows choosing sub-optimal values without significantly influencing the total cost.

Investigations on effect of the orientation on thermal comfort in terraced housing in Malaysia

The design of residential buildings has a significant impact on people's daily life. The ‘terrace house’ form constitutes the majority of the residential building stock in Malaysia. The lack of thermal comfort in terrace houses is mainly due to the poor thermal properties of the building materials and to design factors [1]. The evaluation is derived from a series of computer simulations using commercially available software. This paper concentrates on analysing the effect of the orientation of the existing case of a typical terrace house in Malaysia by finding the dynamic indoor air temperature for each orientation. Copyright , Manchester University Press.

Epidemiological investigations into an outbreak of building-associated illness in Singapore.

In August 1991, the Ministry of the Environment was informed of the occurrence of illnesses suspected to be related to a modern, multi-story office building. Investigations revealed that 34 of the occupants on two floors of the building had non-specific ailments such as eye, throat or skin irritation which caused acute discomfort but resolved upon leaving the premises. Case-control study identified a number of factors significantly associated with the illness; viz. a personal history of allergy, asthma or sinusitis; a high level of work-related stress; and a lack of thermal comfort. One feature of the affected offices was numerous high partitions which tended to obstruct air movement. Adjustments of central temperature to compensate for complaints of "stuffiness" had resulted in wide fluctuations of temperature and relative humidity. Indoor air quality measurements also revealed high bacterial counts, a condition aggravated by the raised relative humidity and inadequate air movement. The problems gradually resolved following major modifications at the offices and air-handling units. This episode confirmed the need for further studies of building-associated illness in the tropics.