Hot Zone Research Articles

Development of mathematical correlations to predict performance of forced ventilated Photovoltaic-DSF system in hot composite climate

Performance of Photovoltaic-double skin façade (Photovoltaic-DSF) system in summer has been critical. Owing to high solar ingress, cooling requirement of a building significantly increases. Photovoltaic-DSF system provides a shield and controls the heat gain through fenestration in the interior spaces. In the present article, mathematical correlations are developed to analyse energy behaviour of forced-ventilated Photovoltaic-DSF system in India’s hot summer zone, that is, Jaipur. The Photovoltaic-DSF system has been installed and monitored for Jaipur’s summer months (May to July). L25 Orthogonal array of design parameters (air cavity thickness, air velocity and PV panel’s transparency) and their respective levels have been developed using Taguchi design to perform experiments. Based on experimental results, multiple linear regression has been used to forecast solar heat gain coefficient, PVs electrical power and daylighting illuminance indoors as function of design factors. The statistical significance of mathematical relationships is supported by variance analysis, which is found to be in good accord with field measurements ( R2 > 0.90). The proposed correlations are pragmatic in designing Photovoltaic-DSF systems for hot summer conditions. The Photovoltaic-DSF system with 30% transmittance and air velocity of 5 m/s in 200 mm air cavity thickness achieved maximum energy performance in hot summers.

Investigation of the Hot Deformation Behavior of 22Cr‐25Ni Austenitic Heat‐Resistant Steel by Combining Constitutive Model and Processing Map

The hot deformation behavior of 22Cr‐25Ni austenitic heat‐resistant steel at the temperatures of 950–1150 °C and strain rates of 0.01–10 s−1 is studied by isothermal compression test. It is found that the dynamic recrystallization (DRX) degree of the steel increases with the increase of temperature. The DRX degree decreases with the increase of the strain rate from 0.01 to 1 s−1, whereas the DRX degree increases with the increase of the strain rate from 1 to 10 s−1. The hot deformation activation energy is as high as 624.25 kJ mol−1 due to the addition of a large number of alloying elements. The typical strain compensation Arrhenius constitutive model established can be used to roughly predict the hot flow behavior of the steel. Furthermore, a modified model considering the influence of strain rate and deformation heat on the deformation process is proposed and showed higher accuracy (statistical parameters r = 0.994 and average absolute relative error = 4.59%). The DRX zone of the steel is determined to be 1080–1150 °C/0.01–0.1 s−1 through processing map analysis, representing the appropriate hot working zone. The microstructure corresponding to the instability zone in the processing map exhibits deformation concentration bands or necklace structures.

Panoramic heat map for spatial distribution of necrotic lesions.

In this study, we aimed to visualize the spatial distribution characteristics of femoral head necrosis using a novel measurement method. We retrospectively collected CT imaging data of 108 hips with non-traumatic osteonecrosis of the femoral head from 76 consecutive patients (mean age 34.3 years (SD 8.1), 56.58% male (n = 43)) in two clinical centres. The femoral head was divided into 288 standard units (based on the orientation of units within the femoral head, designated as N[Superior], S[Inferior], E[Anterior], and W[Posterior]) using a new measurement system called the longitude and latitude division system (LLDS). A computer-aided design (CAD) measurement tool was also developed to visualize the measurement of the spatial location of necrotic lesions in CT images. Two orthopaedic surgeons independently performed measurements, and the results were used to draw 2D and 3D heat maps of spatial distribution of necrotic lesions in the femoral head, and for statistical analysis. The results showed that the LLDS has high inter-rater reliability. As illustrated by the heat map, the distribution of Japanese Investigation Committee (JIC) classification type C necrotic lesions exhibited clustering characteristics, with the lesions being concentrated in the northern and eastern regions, forming a hot zone (90% probability) centred on the N4-N6E2, N3-N6E units of outer ring blocks. Statistical results showed that the distribution difference between type C2 and type C1 was most significant in the E1 and E2 units and, combined with the heat map, indicated that the spatial distribution differences at N3-N6E1 and N1-N3E2 units are crucial in understanding type C1 and C2 necrotic lesions. The LLDS can be used to accurately measure the spatial location of necrotic lesions and display their distribution characteristics.

Quantification of the interactions between indoor environmental conditions and human thermal comfort and susceptibility in tropical coastal environments

The indoor environment in most of the tropical coastal regions is associated with the residents’ health and well-being. However, limited studies reported on quantifying the interrelation between indoor environmental quality, thermal comfort and residents’ health risks in such climatic regions. Here, we evaluate indoor thermal comfort in coastal eastern India that falls under the ‘ Tropical Savanna’ climatic region. The perception survey was conducted to collect primary data in summer, monsoon, post-monsoon and winter across the year and the perception of warmth appeared to have a similar trend to direct and rational human thermal indices derived from a composite body heat exchange. Results indicate that indoor thermal stress significantly differed ( p < .05) between seasons and across study locations. The maximum summer and monsoon days lay in a warm to very hot zone. Additionally, most of the heat-related stress or disorders significantly differed ( p < .01) amongst different age groups of people. Finally, a principal component analysis using the human thermal indices yielded three groups of heat-related symptoms (a) physical fatigue and responses, (b) neural stressors and (c) hyperhidrosis disorder. Overall, results suggested that physical fatigue and responses arose predominantly from climate-induced thermal stress. The study recommends an effective bioclimatic design strategy following human-environment friendliness that can improve indoor thermal comfort in coastal eastern India.

The synthesis of the rare earth A2Zr2O7 single crystals by simplified laser-heated floating hot zone and pedestal methods

The condensed matter community is in constant search for efficient and feasible methods for the synthesis of diverse compounds, especially in the single-crystalline form. We present a recipe for the simplified synthesis of high-quality single crystals of rare-earth zirconates A2Zr2O7, important from both the fundamental and technical application viewpoints,. The developed preparation route allows to effectively, repeatedly, and reliably synthesise the high-quality precursors and single crystals of desired compositions, avoiding contamination and difficulties connected with standard polycrystalline-precursor preparation. Simultaneously, the method is straightforward, saving time, energy, and personnel. In addition to previously reported single crystals, several new single crystals from the A2Zr2O7 series were prepared, including the previously unreported compound Tm2Zr2O7. The high quality of the synthesised samples was proven employing electron microscopy, X-ray diffraction, laboratory and synchrotron radiation diffraction, and neutron powder and Laue diffraction techniques. The crystal structures and structural parameters of the individual compounds were determined and discussed in view of previous reports on A2Zr2O7 and other A2B2O7 series (B stands for d- or p-elements). The introduced synthesis route is proposed to serve well not only for several other A2B2O7 series, but also for a variety of unrelated compounds.

Maximizing solar energy generation: guidelines for optimizing photovoltaic panel placement on building facades

PurposeThis purpose of this paper is to address the research problem of optimizing photovoltaic (PV) panel placement on building facades to maximize solar energy generation.Design/methodology/approachThe study examines the significance of various design configurations and their implications for PV system performance. The research involves analysis of relevant literature and energy simulations. An exemplary case study is conducted in a hot climate zone to quantify the impacts of PV panel placement on energy generation. Various application scenarios are developed, resulting in 28 scenarios for PV on building facades. Energy simulations using Grasshopper Rhino software and Ladybug plugin components are performed.FindingsThe paper identifies key factors influencing PV panel placement and energy generation through qualitative analysis. It introduces an appropriateness matrix as a decision-making framework to evaluate placement options. The study identifies design configurations and external features impacting PV location selection and performs a qualitative classification to determine their impact on energy generation.Practical implicationsThe results and decision-making framework enable informed choices based on solar radiation levels, shading conditions, and building requirements. Optimizing PV panel placement enhances solar energy harvesting in buildings, benefiting architects and engineers.Originality/valueThe novel contributions of this paper include practical insights and guidance for strategically placing PV panels on building facades.

A preliminary investigation of a novel solar-powered absorption-desiccant-radiant cooling system for thermally active buildings

Desiccant air-conditioning systems are considered a competitive alternative to conventional vapor compression cycles. However, the literature lacks detailed studies of such systems when coupled with thermally active buildings and powered by solar energy due to the complexity of modeling and controlling the system. In the present study, a novel hybrid desiccant-dehumidification-absorption system, driven by external compound parabolic concentrators (DDA-XCPC), is used to serve a typical office space in a hot climate zone. The entire system is modeled and simulated dynamically in the TRNSYS environment. The current study investigates the proposed system performance in terms of the achieved thermal comfort, energy consumption, solar fraction, life cycle costs, and carbon emissions. The results reveal superior thermal comfort levels with percentages of people dissatisfied below 5.6 %. The daily solar fraction ranged between 41 and 90 %, with an average of 49 %, whereas the coefficient of performance varied between 0.46 and 1.38 while having a season average of 0.86. Compared to a conventional system, driven by a gas boiler, the proposed system increased the life cycle costs by 6,824 USD due to the large capital investment of the solar thermal loop. However, each 1,000 USD of additional expenses was accompanied by a cutdown of 4,619 kg of CO2 emissions. Increments in the solar system’s capacity (i.e., solar collector area and storage tank volume) have adverse and favorable impacts on the economic and environmental performances, respectively. Therefore, the system can be a viable option whenever green energy production is prioritized and considerably incentivized.

Low‐Temperature Epitaxy of Perovskite WO3 Thin Films under Atmospheric Conditions

As Si electronics hits fundamental performance limits, oxide integration emerges as a solution to augment the next generation of electronic and optical devices. Specifically, oxide perovskites provide diverse functionalities with a potential to create, tune, and combine emergent phenomena at interfaces. High‐level crystalline order is needed to realize these functionalities, often achieved through epitaxy. However, large‐scale implementation in consumer devices faces challenges due to the need for high‐temperature deposition in complex vacuum systems. Herein, this challenge is addressed using atmospheric pressure spatial chemical vapor deposition, a thin‐film fabrication technique that can rapidly produce uniform films at sub‐400 °C temperatures under atmospheric conditions over ≈cm2 areas. Thus, the deposition of epitaxial perovskite tungsten trioxide, WO3, thin films is demonstrated at a rate of 5 nm min−2 on single‐crystal substrates at 350 °C in open‐air conditions enabling a high‐throughput process. The resulting films exhibit crystallographic and electronic properties comparable to vacuum‐based growth above 500 °C. The high‐quality epitaxy is attributed to the energetics of the exothermic decomposition reaction of the W[CO]6 precursors combined with the stabilization of a hot zone near the substrate surface. From this work, the way can be paved for low‐temperature atmospheric‐pressure epitaxy of a wide range of other perovskite thin films.

Experimental Study on Thermal Environment and Thermal Comfort of Passenger Compartment in Winter with Personal Comfort System

The combined heating method of seat heating and air conditioning (A/C) was applied in the passenger compartment under different experiment conditions, using thermocouples to continuously measure the wall surfaces and air temperatures in the passenger compartment and the passengers’ skin temperatures of 17 segments. Meanwhile, a subjective evaluation questionnaire survey was conducted using a nine-point evaluation scale on the local and overall thermal sensation and thermal comfort of the passengers, and the data from the questionnaire were analyzed with the ANOVA method. The results showed that the use of the heating pad directly affected the changes in human skin temperature, which in turn affected the local and overall thermal sensation and thermal comfort. For the two thermally stimulated segments of the back and under the thighs, the skin temperature of the back was higher than that of the thighs. Using the heating pad resulted in a rapid increase in the mean skin temperature in the early period of the experiment. Thermal sensation of the back and under-thighs shifted rapidly towards the hot zone in the first 10 min, and then settled around +3, with even more significant differences between the groups. Thermal sensations in non-thermally stimulated segments changed in relation to their position on the heating pad, with slower changes in those at the “distal” end of the body, the head and the feet. Continued use of the heating pads at lower ambient temperatures maintained overall thermal comfort at a neutral level in the range of 0–1, whereas at higher ambient temperatures there was a gradual deterioration of local and overall thermal comfort.

Development of a microfurnace dedicated to in situ scanning electron microscope observation up to 1300 °C. II. Study of the thermal response of samples.

When conducting in situ experiments at high temperatures in a scanning electron microscope using microfurnaces, controlling the temperature of a sample of a few mm3 placed in the hot zone of the furnace can be a complex task. In most cases, the temperature of the sample is estimated by means of a thermocouple placed in the hot body of the furnace, and the assumption made is that the temperature of the furnace is the temperature of the sample. In this work, a detailed understanding of the thermal response of the sample placed in the hot zone of the furnace is proposed. Temperature differences due to contact resistance between the furnace surface and the sample, the nature of the sample, and the sample geometry are calculated with a numerical model and measured experimentally on a dedicated test bench. Three technical solutions (bonding, sandwiching, and mini-crucible) for limiting temperature differences between the furnace surface and sample are proposed and validated by numerical calculations and experimental measurements.

The effects on heat and oxygen transport of different heat shield and sidewall insulation designs during continuous Czochralski silicon crystal growth

Numerical work has been done to optimize the hot zone for the continuous Czochralski growth of 8-inch diameter silicon crystals using a double-crucible system. Thicker insulation layers on a high-heel-shaped heat shield and the sidewall insulation led to a reduction in the heater power of more than 40%, a decrease in the oxygen content, and a significant flattening of the growth interface. This design also allowed a stronger argon gas flow near the outer free melt surface and the quartz crucible wall, which prevented the generation of an argon gas vortex in this area. Stronger flow of argon gas would assist in moving more SiO gas and dust out of the chamber. However, the reduction in the outer melt temperature compared to the original design could slow down the melting of the silicon granules.

Spatiotemporal dynamic temperature variation dominated by ion behaviors during groundwater remediation using direct current

Direct current (DC) electric field has shown promising performance in contaminated site remediation, in which the Joule heating effect plays an important role but has been previously underappreciated. This study focuses on the spatiotemporal characteristics and mechanism of temperature change in heterogeneous porous media with applied DC. The heating process can be divided into four phases: preferential heating of the low permeability zone (LPZ), rapid heating in the middle region, temperature drop and hot zone shift, and reheating. The dynamic ion behaviors with complex interplays among reactions, electrokinetic-driven migration, and mixed convection induced an uneven redistribution of ions and dominated the heating rate and temperature distribution. The concentration of major ions near the pH jump decreased to 1% of the initial value, even though ions were continuously pumped into the heating zone. This ion depletion caused a drop in current, heating rate, and temperature. Here ions cannot be delivered rapidly into the ion-depleted zone by electromigration due to the potential flattening in the surrounding region. The presence of LPZ intensified the nonuniformity of ion redistribution, where a regional focusing of water-soluble ions was observed, and weakened the temperature rebound compared with that using homogeneous sand. These results provide a new perspective on the regulation of DC heating in site remediation.

Spatial-temporal change of river thermal environment and anthropogenic impact in China

River water temperature is important and closely related to river ecosystem, concerning fishery industry, human health, and the land-sea exchange of nutrients, especially for great powers with a good deal of heat emission from once-through cooling systems of thermal power plants. However, the changes in river water temperature under the joint action of climate change and human activity such as the heat emission have not been well investigated for rising powers, hampering environmental policy making for sustainable development. Therefore, we have taken advantage of a recently-developed land surface model including river water temperature calculation with anthropogenic thermal discharge and zonal statistics to quantitatively make out the river water temperature variation and the man-made influence over the past thirty years (1981–2010) in China for the first time. Results show that the estimated water temperature in major rivers is generally close to the observation with the r2 of 0.83, though the underestimation exists in some rivers. The river water in the Pearl River Basin was the warmest with the mean temperature of 19.2 °C and the others in order were in the Southeast Basin, the Huaihe River Basin, the Yangtze River Basin, the Haihe River Basin, the Yellow River Basin, the Southwest Basin, the Song-Liao River Basin, and the Continental Basin, ranging from 16.7 °C to 6.3 °C. The Huaihe River Basin had the fastest mean increase rate of ca. 0.27 °C decade−1, while the slowest mean increase rate of ca. 0.13 °C decade−1 existed in the Pearl River Basin. At the subbasin scale, a meridionally-distributed hot spot zone (along the 115°E) of the increasing water temperature has been identified, where the trends ranged from 0.2 °C decade−1 to 0.5 °C decade−1. Air temperature exerted a major control on the spatial pattern of climatological water temperature, while both air temperature and downwelling solar flux played a leading role in the distribution of water temperature change trends. Although anthropogenic thermal emission heated the rivers locally, the impacts in the Song-Liao River, the Haihe River, the Huaihe River, and the middle and lower reaches of Yellow River and Yangtze River had been raised up to ca. 4.5 °C, when comparing with those controlled by climate change only. In general, these results show an acceptable level of river water temperature simulation in the land surface model, and could provide a scientific reference for the assessment on riverine thermal environment under the climate change and social impact in China.

Reliability-Based Pavement Roughness Progression Modeling Using Bayesian Approach

This paper aims to develop reliability-based roughness progression models for bituminous pavements across different climatic zones in India. The methodology involves dividing the Indian geographical region into six climatic zones with specific climatic characteristics that influence pavement deterioration. This delineation is achieved using K-means clustering and considers parameters such as temperature, rainfall, and humidity. The roughness progression models and reliability interpretations are developed through a Bayesian regression framework. Initially, International Roughness Index (IRI) progression models are created for three climatic zones: hot and dry, warm and humid, and moderate. These models are based on time series data from 2015 to 2016, gathered from 130 pavement sections in each zone. To validate the models, additional time series data from 2016 to 2017 are utilized. The forecast results indicate that the hot and dry zone exhibits the highest IRI progression rate for specified causal variable values, followed by the warm and humid zone and the moderate zone. The adoption of the Bayesian regression framework provides probabilistic parameter distributions for model coefficients, enabling the assessment of model-level reliability. The study demonstrates that, by adjusting the quartile of causal variables, the overall reliability of the model can be improved, thereby reducing the deviation from actual IRI values. Moreover, it is possible to evaluate variable-level reliability by examining the influence of individual variables on roughness progression.

Distribution characteristics and microbial synergistic degradation potential of polyethylene and polypropylene in freshwater estuarine sediments

The microbial degradation of polyethylene (PE) and polypropylene (PP) resins in rivers and lakes has emerged as a crucial issue in the management of microplastics. This study revealed that as the flow rate decreased longitudinally, ammonia nitrogen (NH4+-N), heavy fraction of organic carbon (HFOC), and small-size microplastics (< 1 mm) gradually accumulated in the deep and downstream estuarine sediments. Based on their surface morphology and carbonyl index, these sediments were identified as the potential hot zone for PE/PP degradation. Within the identified hot zone, concentrations of PE/PP-degrading genes, enzymes, and bacteria were significantly elevated compared to other zones, exhibiting strong intercorrelations. Analysis of niche differences revealed that the accumulation of NH4+-N and HFOC in the hot zone facilitated the synergistic coexistence of key bacteria responsible for PE/PP degradation within biofilms. The findings of this study offer a novel insight and comprehensive understanding of the distribution characteristics and synergistic degradation potential of PE/PP in natural freshwater environments.

Multi-performance collaborative optimization of existing residential building retrofitting in extremely arid and hot climate zone: A case study in Turpan, China

Multi-dimensional performance optimization of buildings is crucial to achieving comfort and realizing green and sustainable development. This study developed a multi-performance collaborative optimization framework (MPC_BPO) to analyze modern residential retrofitting in extremely arid and hot climate zone. The parametric environmental simulation (PES) demonstrated high consistency with actual operating results (R2 > 0.92), and the multi-objective optimized artificial neural network (OPT-ANN) effectively established a high precision multi-performance prediction model (R2 > 0.96). Various multi-objective algorithms exhibited a high convergence level in the high-dimensional complex optimization process. The entropy weight and subjective weight methods ranked the Pareto frontier solution set, where the optimization scheme dominated by energy use intensity (EUI) increased daylighting index (DLI) and thermal comfort hours (TCH) by 12.32 % and 6.67 %, respectively, while reducing EUI by over 8.47 %. Applying different scenarios to other household buildings verified the generalization characteristics, showing overall high consistency despite variations in performance indicators. This research provides a scientific basis for improving residential performance in special climate zones through an appropriate framework. Using scientific methods, it analyzes the intrinsic logic between high-dimensional parameters and multiple building performances.

Energy and economic performance optimization of a window with variable transparency shape-stabilized PCM in hot summer and cold winter climate zone

Improving the thermal performance of windows is important for building energy efficiency. Filling windows with variable transparency shape-stabilized phase change materials (VTSS-PCM) improves the thermal inertia of windows while avoiding the leakage of PCM. In this paper, a new type of VTSS-PCM window was proposed, tested, simulated and optimized in hot summer and cold winter climate zone. A numerical model of the VTSS-PCM window was built, and the model was validated using experimental tests. On this basis, three key parameters of VTSS-PCM were investigated and optimized. Finally, the energy and economic performance of the optimized VTSS-PCM window were compared with a typical hollow glass window. The results showed that the total annual unfavourable heat transfer (TAHT) and the annual investment cost (AIC) of the VTSS-PCM window obtained from the optimization were 118.16 kWh/m2 and 8.53 CNY/m2, respectively. Compared with the hollow glass window, the VTSS-PCM window reduced the TAHT by 30.14% and the total annual cost by 28.39%. The VTSS-PCM window produced a better development potential in terms of energy performance and economic performance. This study provided a reference for the application of the VTSS-PCM window in hot summer and cold winter regions of China.

Effects of an Annular Baffle on Heat Transfer to an Immersed Coil Heat Exchanger in Thermally Stratified Tanks

Abstract The effect of a cylindrical baffle on heat transfer to an immersed heat exchanger is investigated in initially thermally stratified tanks. The heat exchanger is located in the annular region created by the baffle and the tank wall. Three different cases of initial thermal stratification are explored, and in each case, experiments are conducted with and without the baffle in the stratified tank and in a comparable isothermal tank with the same initial energy, enabling exploration of the role of the baffle in a stratified tank and the role of stratification in tanks with or without the baffle. The baffle maintains the high initial temperature of the upper zone of the stratified tank for 10–16 min, as cool plumes that form on the heat exchanger are confined to the annular baffle region until they exit at the bottom of the tank. Regardless of stratification, the baffle always improves heat transfer to the immersed heat exchanger. In the isothermal tanks, the baffle increases total energy extracted in the first 30 min of discharge by over 20%. In stratified tanks, the baffle increases total energy extracted in 30 min of discharge by 9–16%. Initially, improvement in heat transfer in stratified tanks is due to the higher driving temperature differences around the heat exchanger. Later, after all the water from the hot zone has entered and flowed through the baffle, the tank is basically isothermal, and velocity increases as the fluid temperature drops, maintaining rates of heat transfer higher than that in the tank without the baffle. Stratification improves heat transfer in tanks without a baffle because, by design, the driving temperature difference between the heat exchanger wall and the surrounding fluid is considerably higher. However, in tanks with the baffle, stratification has only a modest positive effect on heat transfer to the immersed heat exchanger.

The adoption of ceiling fans as an alternative cooling strategy to air-conditioning: what can we learn from building sustainability index certified homes?

ABSTRACT Ceiling fans have been promoted as an alternative cooling technique to save energy, while their adoptions in the residential sector have yet to be investigated. This study analysed the adoption of ceiling fans in residential buildings and compared their energy-saving potential with that of air-conditioning in Building Sustainability Index (BASIX) certificated single (n = 268,558) in New South Wales, Australia, from 2011 to 2019. Four climate zones were classified according to heating and cooling hours via k-means, based on which predictive models for the relationship between cooling technologies and energy-saving levels were established via machine learning. Dwellers in the hot zone of New South Wales would be more likely to adopt ceiling fans. In the living rooms, dwellers could adopt ceiling fans alone, while in bedrooms, dwellers could adopt air-conditioning in addition to ceiling fans. This study provides empirical evidence on the adoption of ceiling fans in green buildings and helps to map out the low carbon solutions using alternative cooling in the residential sector.

Relationship between indoor and outdoor temperatures in winter in the Hot Summer and Cold Winter Zone of China - Considering two sources of outdoor temperatures and different indoor heating methods

Thermal exposure is a global issue related to health. Environmental health studies often overlook indoor temperature in comparison to outdoor temperature. Exploring indoor and outdoor temperatures and their relationship is an important part to understand individual heat exposure. The aim of this study is to explore the indoor and outdoor temperatures and their relationship during winter, using weather station and ERA5-Land reanalysis outdoor temperature. Field experiments were conducted in both districting heating and non-district heating dwellings in the Hot Summer and Cold Winter zone of China, taking into account the influence of cold spells. Significant linear correlation was found between the weather station and reanalysis outdoor temperature. The indoor temperature of the district heating group was 8.4 °C higher than that of the non-district heating group. When the outdoor temperature approached 0 °C, the indoor-outdoor temperature difference of the district heating group was twice that of the non-district heating group. The non-district heating group experienced greater fluctuations in indoor temperature during the cold spell. The outdoor temperature could only partially explain indoor temperature, especially under the condition of district heating. The study suggests that outdoor temperature alone is insufficient when evaluating individual thermal exposure in winter. Furthermore, occupants with district heating and non-district heating may have different vulnerabilities, and thermal safeguard strategies in winter are suggested to be designed more targeted. This study may provides insights from the perspective of thermal environment for temperature and health studies.