Evaluation Of Thermal Environment Research Articles

Human thermal comfort model and evaluation on building thermal environment

A healthy and comfortable thermal environment has become the core focus on building environment evaluation. The key is to realize room temperature regulation based on the demand for human thermal comfort. The study aims to build the core of building thermal environment regulation, building thermal environment evaluation system, to achieve accurate evaluation and prediction of thermal comfort temperature for different type buildings and occupants. Considering the differences between traditional and smart buildings in building intelligence, whose thermal environment evaluation frameworks are proposed respectively. Taking the traditional buildings in a typical city from the severe cold zone as an example, the thermal comfort models of different type buildings, heating periods, and occupants are established. Furthermore, the corresponding correction factors are proposed for age, gender, BMI and metabolic rate. This study provides theoretical support for the evaluation of building thermal environments.

Modeling a solar shading system that controls heat gain by using solar energy to change louver slat angles

In this study, we propose a model for a passive louver system that adjusts slat angles using solar heat energy. The model is structured in two stages: predicting the surface temperature of a solar collector plate and using this temperature to determine the slat angles. The system was installed and monitored in a building in Okinawa, Japan, to validate the model’s accuracy with field measurements. The validation showed that while the model accurately predicted the daily opening and closing times of the louvers, it faced limitations in minute-by-minute variations, making it less suitable for scenarios requiring instantaneous state evaluations, such as lighting environment assessments. Additionally, predicting the temperature for the double-skin façade was challenging and could affect overall model accuracy. Despite these issues, the model effectively achieved its primary goal of predicting annual energy consumption by accurately forecasting the daily opening and closing times of the louvers. The model’s fast computation speed and simplicity make it particularly suitable for annual energy simulations and easy to integrate with existing energy simulation programs. Further research is needed to enhance minute-by-minute reproducibility and integrate temperature predictions for double-skin façades, ensuring a comprehensive evaluation of both thermal and lighting environments.

Experimental evaluation of thermal environment built by decoupled radiant cooling system with low radiant cooling temperature

Decoupled radiant cooling system (DRCS)1, which utilizes an infrared-transparent membrane to isolate the radiant surface from the ambient air, can provide radiant cooling temperature below the dew point to prevent condensation and increase cooling capacity. However, whether the thermal environment built by DRCS with low radiant cooling temperature meets thermal comfort needs further investigation. This includes: 1) Do the environment parameters meet the comfort standard? 2) How do subjects evaluate the environment's comfort? Thus, environmental monitoring and questionnaire surveys were conducted to evaluate the thermal environment of DRCS in summer. Initially, the environment parameters were measured and 32 subjects were recruited to perform subjective and physiological response tests. Further, the environment was evaluated using thermal comfort models and thermal sensation votes. Finally, the applicability of the predicted mean vote (PMV) model was examined by comparing actual and predicted thermal sensations. The results confirmed that thermal environment built by DRCS satisfied the ASHRAE Standard criteria. The neutral operative temperature was around 24.8°C and the comfort environment was achieved between 23.3°C and 26.5°C. Moreover, PMV model has a high accuracy in predicting the thermal sensation of DRCS.

Evaluation of energy-saving potential and indoor thermal environment of passive solar houses in various heating climate regions of China

ABSTRACT Passive solar houses comprise crucial strategies of reducing heating and cooling energy for buildings, which have been extensively used in plenty of nations. This study develops a study on indoor thermal environment, the energy-saving performance and natural lighting in different heating climate regions (represented by Lhasa, Xining and Urumqi). An attached-sunspace solar house integrated with phase change material floors is also proposed to ameliorate indoor thermal comfort and simultaneously diminish the heating energy consumption. In addition, the dominant factors analysis of building envelope affecting building energy consumption are sensitively studied. Moreover, the influence of the depth of sunspace and the intensities of internal heat gain on indoor thermal conditions and heating energy consumption are further analyzed. The results indicate that among the three types of solar houses, the passive solar sunspace offers the most stable indoor temperature and Trombe-wall solar houses and attached-sunspace solar houses have striking energy-saving advantages compared with the traditional houses. And the annual power consumption of 695.1 kWh, 427.4 kWh and 688.8 kWh in Lhasa, Xining and Urumqi can be saved in view of natural lighting respectively. Additionally, the whole natural temperature of attached-sunspace solar house is on the rise apparently when the PCM floors are embedded in the house and the energy saving fraction of these three regions is 81.9% for Lhasa, 68.8% for Xining, 55.7% for Urumqi respectively with the integration of phase change floors. The sensitivity analysis of key parameters impacting building energy consumption from high to low are the heat transfer coefficient of external wall, the ratio of window to wall, air tightness, the heat transfer coefficient of external window, and the heat transfer coefficient of roof. The depth of 1.2 m for sunspace is recommended as the optimal choice. Indoor natural temperature is on the rise as intensities of internal heat gain increase. The same downward trend for the main bedroom and the whole building is displayed with the increasing interior heat sources in terms of annual heating load.

Indoor Thermal Environment Evaluation for Emergency Medical Tents in Heating Season: Onsite Testing and Case Study in China

In this study, the standard tent used by the China International Medical Team (Sichuan) was used as the research object to study the internal temperature change in medical tents in a low-temperature environment relying on heating equipment. Method: Four temperature sensors were arranged along the horizontal direction at a 1.2 m height in the medical tent, and more sensors were installed at heights of 0.1, 0.2, 0.6, 1.2, 1.8, 2.4, and 2.5 m. A total of 11 temperature sensors were set. Temperature tests were conducted in January and February 2021 in Chengdu, Sichuan Province. During the test, the running time of the heating equipment was controlled in real time according to the temperature change trend. A Kolmogorov–Smirnov(K-S) test was used to verify the reliability of the experimental data. The temperature change trend was used to characterize the influence of the heating and cooling equipment on the temperature change inside the tent. Results: Due to the position angle of the heating equipment and the influence of the external environment, the spatial distribution of the ambient temperature inside the medical tent was obviously uneven. In winter, an electric heater with a heating power of about 2500 W can increase the internal temperature of the tent to 16.7 °C, significantly improving the internal thermal environment of the medical tent. The ambient temperature in the medical tent is positively correlated with the height and the installation position of the heating equipment. Conclusion: Medical tents can maintain the ambient temperature well to meet medical needs with the support of heating equipment with sufficient power. The temperature distribution law of medical tents in this experiment has good guiding significance for the placement angle of heating equipment and the configuration position of medical equipment and provides a reference for the development of thermal insulation materials for medical tents.

Research on indoor thermal environment evaluation and thermal adaptation in winter of Japanese wood-framed detached houses

Indoor space is the place where human beings live, and how to meet people's indoor thermal comfort needs in the context of energy scarcity is one of the important issues for sustainable development of buildings, and the evaluation of the indoor thermal environment has become the key to it. In the case of Japanese wood-framed detached houses, which contain different types of space forms, it is difficult to accurately apply the existing thermal environment evaluation results. In this study, detached houses in Kitakyushu City, Japan, were selected as the research object, and continuous measurements and subjective questionnaires of the indoor thermal environments were conducted based on three modes of no heating, continuous heating, and intermittent heating, in order to grasp the current information of the thermal comfort in detached houses. The results showed that: 1. The average indoor temperatures in both Washitsu and Yoshitsu were lower than the human thermal comfort range; 2. The thermally neutral temperature of 15.9 °C in Washitsu was lower than that of 17.7 °C in Yoshitsu, and the acceptable temperature zones were (14.3–17.5 °C) and (15.6–18.9 °C), respectively; 3. Develop modified models (PMVe) and adaptive predicted mean vote (aPMV) model suitable for thermal comfort evaluation of detached houses in Japan. The results of this study will help to improve the indoor thermal environment and thermal comfort evaluation system of Japanese detached houses, and provide a useful reference for the study of the renewal and renovation of houses in this area.

The Chinese thermal comfort dataset

Heating and cooling in buildings accounts for over 20% of total energy consumption in China. Therefore, it is essential to understand the thermal requirements of building occupants when establishing building energy codes that would save energy while maintaining occupants’ thermal comfort. This paper introduces the Chinese thermal comfort dataset, established by seven participating institutions under the leadership of Xi’an University of Architecture and Technology. The dataset comprises 41,977 sets of data collected from 49 cities across five climate zones in China over the past two decades. The raw data underwent careful quality control procedure, including systematic organization, to ensure its reliability. Each dataset contains environmental parameters, occupants’ subjective responses, building information, and personal information. The dataset has been instrumental in the development of indoor thermal environment evaluation standards and energy codes in China. It can also have broader applications, such as contributing to the international thermal comfort dataset, modeling thermal comfort and adaptive behaviors, investigating regional differences in indoor thermal conditions, and examining occupants’ thermal comfort responses.

Thermal environment evaluation and thermal comfort zone deviation ——a case study of Chinese seaweed house in summer

Renewing the vitality of traditional ecological dwellings in the context of global carbon peaking and carbon neutrality targets has become one of the important topics in today's building sustainability research, and the evaluation of thermal comfort in traditional dwellings is the key to it. In this paper, one of the most representative ecological dwellings in the world, the “Seaweed House”, was selected as the research object. Firstly, the physical environment of a seaweed house in Dazhuang Xujia Village was measured from July 29 to August 3, 2022. Secondly, a thermal comfort questionnaire was conducted to grasp the current information of the thermal comfort in seaweed house. The results show that:1. The humidity of seaweed houses in summer is too high. 2. Residents have a thermally neutral temperature of 26.9 °C, an acceptable temperature region of (24.8–29.1 °C), and a thermally desired temperature of 25.8 °C. 3. The adaptive predicted mean vote (APMV) model suitable for thermal comfort evaluation of seaweed houses was developed. The results of the study provide a precise theoretical guide for the study of thermal comfort evaluation models in this region, and a useful reference for the study of the renewal and renovation of the seaweed houses.

Thermal Comfort Assessment in University Classrooms: A Discriminant Analysis for Categorizing Individuals According to Gender and Thermal Preferences

The concern with the well-being of users in buildings has become increasingly essential, covering aspects related to health, energy efficiency, and productivity. The thermal environment evaluation in buildings has become more frequent due to the time people spend inside them. In this context, this study aimed to analyze thermal comfort in classrooms at a Brazilian University. During the autumn, 50 measurements were performed, resulting in 519 valid responses. The results of the linear regression analysis revealed that the thermal comfort range for females was 20.39–22.19 °C, while for males it was 19.47–22.56 °C. Through discriminant analysis, participants were classified based on their thermal sensation vote (TSV), predicted mean vote (PMV), and thermal preference votes (PREF), achieving a success rate of 76.1% for females and 81.6% for males in forming the groups, which demonstrates the effectiveness of discriminant functions in predicting thermal comfort for both groups. These results highlight the importance of considering gender differences in the search for thermal comfort conditions and providing guidelines that promote the well-being of occupants and the conscious use of energy. This implies adjusting the thermal conditions according to the specific needs of males and females in classrooms, always seeking to provide a suitable environment for activities, and considering energy efficiency and users’ productivity.

Indices for dynamic evaluation of indoor humidity and thermal environment

Moisture sources release wet-components into indoor air, affecting the occupants’ health, air conditioning energy consumption, and building service-life. Wet-component evaporation and diffusion are dynamic processes, and yet existing indices are limited in their ability to accurately describe moisture sources dynamically influencing indoor air. Here we propose two indices CRIt(H), an index of the rate of humidity contribution change, and CRIt(c) as the rate of indoor climate contribution change. Taking a humidifier as the source, we use our indices to compare by experiment the impact of source parameters on a variety of ambient conditions over space and time. Our approach accurately reflects how the moisture source affect humidity and temperature, with identification of specific stages of dynamic influence. This study will be beneficial for the establishment of transient indoor environmental models, regulation of air-conditioning systems, and sustainable control of the indoor environment.

Combined Effects of the Thermal-Acoustic Environment on Subjective Evaluations in Urban Park Based on Sensory-Walking

Studying the impact of various factors on environmental perception is crucial because humans live in an environment where these factors interact and blend. The thermal-acoustic environment is the major factor that affects the overall perception of urban parks. This study focuses on urban parks in the subtropical region, with Xihu Park in Fuzhou, China, as the research area. Through measurements and questionnaires, this study explores the effects of the thermal-acoustic environment in urban parks on subjective evaluation (thermal assessment, acoustic assessment, and overall environmental assessment). The results reveal that: (1) a higher temperature significantly increases the sensation of heat and lowers thermal comfort, heat acceptance, and overall thermal environment evaluation scores. The type of sound source has a significant positive impact on thermal assessment, and the higher the ranking of the sound source type, the greater its positive impact on thermal assessment. (2) Regarding acoustic evaluation, higher sound pressure level is associated with more negative subjective ratings of loudness, harshness, intensity, and excitement. In contrast, positive sound sources can enhance comfort, preference, disorder, coordination, and overall soundscape evaluation. Additionally, temperature increases tend to result in more negative harshness, intensity, and coordination ratings. The interaction between temperature and sound pressure level also significantly affects subjective loudness, harshness, and intensity. (3) Overall environmental evaluation is also affected by temperature, with increasing temperatures leading to decreased comfort and satisfaction while increasing irritation. High sound pressure environments result in worse overall irritation ratings, while positive sound sources can significantly enhance overall comfort, irritation, and satisfaction ratings. Furthermore, the interaction between temperature and sound pressure level significantly impacts overall irritation and satisfaction ratings. These findings are significant for managing and improving the park’s thermal environment and soundscape, providing a practical framework for landscape architects.

Multivariate thermal environment data extraction and evaluation: A neighborhood scale case in Guangzhou, China

Multivariate thermal environment data extraction and evaluation: A neighborhood scale case in Guangzhou, China

Evaluation of thermal environment and human thermal comfort in 8 types of public places from 2019 to 2021

Objective: To evaluate the thermal environment of different types of public places and the thermal comfort of employees, so as to provide scientific basis for the establishment of microclimate standards and health supervision requirements. Methods: From June 2019 to December 2021, 50 public places (178 times) of 8 categories in Wuxi were selected, including hotels, swimming pools (gymnasiums), bathing places, shopping malls (supermarkets), barber shops, beauty shops, waiting rooms (bus station) and gyms. In summer and winter, microclimate indicators such as temperature and wind speed were measured in all kinds of places, combined with the work attire and physical activity of employees in the places. Fanger thermal comfort equation and center for the built environment (CBE) thermal comfort calculation tool were used to evaluate the predicted mean vote (PMV), predicted percent dissatisfied (PPD) and standard effective temperature (SET) according to the American Society of Heating, Refrigerating and Air-Conditioning Engineers (ASHRAE) 55-2020. The modification effects of seasonal and temperature control conditions on thermal comfort were analyzed. The consistency of GB 37488-2019 "Hygienic Indicators and Limits in Public Places" and ASHRAE 55-2020 evaluation results on thermal environment was compared. Results: The thermal sensation of hotel, barber shop staff and the gym front-desk staff were moderate, while the thermal sensation of swimming place lifeguard, bathing place cleaning staff and gym trainer were slightly warm in summer and winter. Waiting room (bus station) cleaning and working staff, shopping mall staff felt slightly warm in summer and moderate in winter. Service staff in bathing places felt slightly warm in winter, while staff in beauty salons felt slightly cool in winter. The thermal comfort compliance of hotel cleaning staff and shopping mall staff in summer was lower than that in winter (χ(2)=7.01, 7.22, P=0.008, 0.007). The thermal comfort compliance of shopping mall staff in the condition of air conditioning off was higher than that in the condition of air conditioning on (χ(2)=7.01, P=0.008). The SET values of front-desk staff in hotels with different health supervision levels were significantly different (F=3.30, P=0.024). The PPD value and SET value of the front-desk staff, and the PPD value of cleaning staff of hotels above three stars were lower than those of hotels below three stars (P<0.05). The thermal comfort compliance of front-desk staff and cleaning staff in hotels above three stars was higher than that in hotels below three stars (χ(2)=8.33, 8.09, P=0.016, 0.018). The consistency of the two criteria was highest among waiting room (bus station) staff (100.0%, 1/1) and lowest among gym front-desk staff (0%, 0/2) and waiting room (bus station) cleaning staff (0%, 0/1) . Conclusion: There are different degrees of thermal discomfort in different seasons, under the condition of air conditioning and health supervision, and the microclimate indicators can not fully reflect the thermal comfort of human body. The health supervision of microclimate should be strengthened, the applicability of health standard limit value should be evaluated in many aspects, and the thermal comfort of occupational group should be improved.

Clothing thermal insulation of infant in stroller relating to evaluation of thermal environment of infant

The clothing thermal insulation for individual clothing ensembles of infant and strollers has been clarified. However, the clothing thermal insulation for the combination of them has not been measured at all. The purpose of this study is to examine the typical values of human factors such as the clothing area factor and clothing thermal insulation of an infant in a stroller. As typical clothing ensembles, seasonal combinations of infant clothing with a stroller were selected. The stroller was treated as part of the infant’s clothing. The clothing area factors were measured by using the photographic method. The clothing thermal insulations were measured by using an infant’s thermal manikin. The typical clothing area factor of an infant in a stroller is 3.67 for summer clothing, 3.75 for mid-season clothing, and 4.19 for winter clothing. The typical clothing thermal insulation of an infant in a stroller is 1.23 clo for summer, 1.39 clo for mid-season, and 1.97 clo for winter. The stroller was shown to significantly affect the body heat balance between the infant and the thermal environment.

Influence of Air Velocity on Thermal Comfort and Performance of Students in Naturally Ventilated Classrooms in Tropical Climate

Air velocity is among the most important factors influencing thermal comfort in naturally ventilated spaces in hot and humid tropical climates. It is important to have air velocity that suits comfort needs and enhances the student's learning performance in the classroom, especially in schools that rely only on natural ventilation assisted by ceiling fans. In this study, the thermal comfort and learning performance of students in a selected naturally ventilated classroom at a secondary school in Segamat, Johor, Malaysia, were experimentally evaluated under different air velocity conditions during the peak temperature period during the school session. Throughout the experiment, physical measurement and a subjective evaluation questionnaire were conducted for thermal comfort analysis and to gather the student’s thermal environment evaluation in the classroom. Students’ learning performance was assessed through simple reaction and digit span tests based on the WHO Neurobehavioral Core Test Battery (NCTB). All the assessment results were statistically analyzed, and the relationships among indoor air velocity, thermal comfort, and learning performance were obtained. The result showed optimal learning performance was significant when students felt “slightly cool” and air velocity was more than 0.95 m/s. Hotter environments and a lack of air movement were found to be causes of declining student performance. In conclusion, it is suggested that the comfort zone in a naturally ventilated classroom for school students should be set within the range of -1 (slightly cool) with an air velocity greater than 0.76 m/s.

A new contribution ratio for indoor climate (CRISE) for the contribution evaluation of each heat and moisture source to the specific enthalpy in a closed space

The indoor thermal environment comprises temperature, humidity, wind velocity, and radiant temperature. The spatial distribution of these elements is a combination of the individual responses of the heat and water vapor transported into the space from each source. The contribution ratio for indoor climate (CRI) proposed by Kato, Kobayashi, and Murakami is a single index that evaluates the effect of each heat source on the temperature by breaking down the temperature increase at position x in a room into the effect of each heat source. We extended the CRI concept to three single indices to improve its applicability. Previously, thermal environment evaluation was often performed using a composite index rather than a single index. To evaluate the combined effects of heat and moisture sources, decomposing multiple elements individually and then combining them is desirable. In this study, we propose CRISE to evaluate the contribution of a heat or moisture source to the specific enthalpy at a given point in a closed space. The index was calculated by combining a single index of dry-bulb temperature and absolute humidity. The CRISE is a useful index for evaluating the indoor thermal environment and HVAC load.

Computational analysis and evaluation of thermal comfort environment of a space by reducing the inside air temperature

The tents are used as temporary shelters and evenly they sometimes become a home for a number of years when the returns to permanent shelter is very slow or unaffordable for any person so that the comfort of these shelters are very much essential like home. This paper is primarily concerned with identifying the objectives of reducing the inside air temperature of shelter using different retro-reflective materials. In the present work computational fluid dynamics analysis have been performed for a shelter under the summer climatic conditions to reduce the inside air temperature of shelter using different retro-reflective materials like polyvinyl chloride, wood-fibre, polystyrene, aerogel and phenolic foam. For CFD analysis free stream temperature of air is set 311 K taken with constant heat flux of 900 W/m2 solar radiations is used on roof, second order upwind discretization scheme is used to approximate the solution for momentum and pressure. Result show that that minimum temperature variation of 4.8 degreesK by using retro-reflective material as phenolic-foam and 18.74 % temperature percentage variation compared with other reflective materials.

Analysis of temperature regulation and heat storage effect of the combined phase change envelope in hot summer and cold winter zone

In order to study the character of heat storage and temperature regulation, a mathematical model of the thermal performance of an ideal passive energy storage building is established. Indoor thermal environment evaluation indexes of the passive buildings such as the temperature attenuation coefficient and supercooling degree/superheating degree are proposed. The PCM (phase change materials) layer numbers, the total thickness and the thickness ratio of PCM layers of the combined PCM envelope are analyzed based on the simulation. The result shows that the combined envelope with two-layer PCM has better temperature regulation and heat storage effect. When the total thickness of the combined PCM envelope is 40 mm, and the thickness ratio of the PCM layer from the inside to the outside is13.3:26.7, the annual thermal comfort hours are the longest.

Photothermal performance of plastic greenhouse embedded with phase change materials in translucent envelopes: A dynamic experimental study

An adaptable façade can be a translucent envelope with phase change materials (PTE) integrated into the typical plastic greenhouses to respond to dynamic changes in temperature and daylight. Unlike opaque constructions integrated with phase change materials (PCM), PTE can act as a governor to coordinate light and thermal performance. This paper conducts an experimental investigation on the photothermal performance of plastic greenhouses integrating PTEs. The integration of PTEs requires an evaluation between the different melting temperatures of PCM (PW-18#, PW-25#, PW-28#) and seasons (transition, autumn, winter) rationally design plastic greenhouse featuring tunable indoor daylight and air temperature. The cross-seasonal analysis and thermal environment evaluation are also carried out. The results show that plastic greenhouses with PTEs substantially tune thermal energy storage/release and attenuate indoor daylight. In a separate seasonal investigation, it is observed that PTEs with PW-28# produced adjustable average air temperatures of 26.4 °C and lowered daylight levels of 10,245 lx, making them desirable during transitional seasons. Likewise, PTEs with low melting temperatures are advantageous because of the reduced outside temperature and daylight. According to the cross-seasonal investigation, PTEs with high melting temperatures find it difficult to sustain long-term operation because of the inadequate degree of phase transition cycle. PTEs have the advantage of rebuilding the internal thermal environment and increasing the upper layer's distance from the ground by 2.4 °C. Finding the best states to build a low-cost, easily replaceable passive heating system for plastic greenhouses can be made easier with the help of the understanding of the built-in PTEs.

Convective heat transfer coefficient relating to evaluation of thermal environment of infant

Infants have a low capacity to thermally adapt to their environment and so sufficient consideration must be given to their thermal environment. In investigating an infant's thermal environment, the purpose of this study is to clarify the heat transfer coefficient in natural convection for the posture of an infant in a stroller. The heat transfer coefficients were measured by means of using a thermal manikin. The experimental thermal environment conditions were set for eight cases, at: 16 °C, 18 °C, 20 °C, 22 °C, 24 °C, 26 °C, 28 °C, and 30 °C, and the air and wall surface temperatures were equalized, creating a homogeneous thermal environment. The air velocity (less than 0.2 m/s) and relative humidity (50%RH) were the same for each case. The surface temperature of each part of the thermal manikin was controlled to 34 °C. The difference between the mean surface temperature and air temperature (ΔT [K]) is the driving force for the heat transfer coefficient in natural convection for the posture of an infant in a stroller (hc [W/(m2·K)]). We propose the use of the empirical formula hc = 2.16 ΔT 0.23. The formula of the convective heat transfer coefficient in natural convection of this study can be applied to infants up to about 3 years old.