Analysis Of Thermal Environment Research Articles

Assessing the effects of urban green landscape on urban thermal environment dynamic in a semiarid city by integrated use of airborne data, satellite imagery and land surface model

The response of the urban thermal environment to green space landscapes has been studied previously, while its detailed pattern is insufficiently explored owing to the constraints of spatial and temporal resolution of available datasets. This study uses integrated Thermal Airborne Spectrographic Imager (TASI) data, Landsat TM/ETM and MODIS satellite imagery, and Noah land surface model output to investigate the effects of landscape pattern on the urban thermal environment across Shijiazhuang, China. The present study not merely proposes a generalized framework for the spatiotemporal analysis of urban thermal environment, but also affords several insights into the cooling effects related to urban green space landscapes in semiarid cities. Firstly, trees and lawns show a noticeable disparity in land surface temperature (LST) response to urban green landscape metrics, primarily due to the difference in cooling efficiency via evapotranspiration. This disparity can be explained further by the radiation-shading effect of trees. Secondly, analysis confirms that the composition of urban green space has a substantial impact on LST throughout summer. This pattern is largely stable for trees owing to the constant Bowen ratio, but they are altered for lawns. Conversely, the configurations of urban green space exhibit less impact on LST. These effects vary temporally in magnitude and can be enhanced notably in humid conditions. The lower correlation between the configuration metrics of urban green and LST has to do with the surface resistance alterations and additional cooling effects. Finally, consistent patterns of the impact of urban green space landscape metrics on LST are illustrated at different spatial scales and region sizes but greater effects are revealed for smaller analytical units, further confirming the impacts of urban green landscape on urban thermal environment.

Investigation on thermal environment of subway stations in severe cold region of China: A case study in Harbin

In recent years, numerous subway lines have been under construction with the rapid development of subways in the cold regions of China. Harbin, a typical city in severe cold regions, has harsh winter weather, and the lowest outdoor temperature can reach −37.7 °C. Therefore, the thermal environment of the station and the thermal comfort of passengers are facing huge challenges. Owing to the complexity of the subway environment, few field test studies, especially long-term tests, have been conducted. In this study, long-term field test on the thermal environment, questionnaire survey and thermal comfort analysis of two typical subway stations were conducted. A revised comfort temperature was proposed based on the constant changes in passenger metabolism. The field test results showed that the temperature and moisture content of the station were affected by the type of platform door, interval driving, operating time, and piston effect. The results of the questionnaire survey showed that the temperature, humidity, and thermal comfort of the two subway stations were satisfactory for most passengers. Passengers experienced a noticeable draft only in the aisle. After calculation, the lower limits of the comfortable temperature for the aisle, hall, and platform of the Harbin Metro were determined to be 10.6, 11.2, and 13.8 °C, respectively. The data obtained in this study provide a valuable reference for the construction and operation of subways in severe cold regions.

Actual measurement and analysis of winter thermal environment of a graduate student studio in Shenyang based on Airpak numerical simulation

This paper takes a graduate workshop in shenyang as the research object, and uses Airpak software to conduct numerical simulation analysis on the air distribution and thermal comfort of the fan coil side air supply mode in winter. The measured air supply temperature is 25°C, air supply speed in the x direction for 0.8m / s, 1.5m / s and 2.3m / s three gears, from east to west up to back air supply 3mode. With the increase of air supply speed, the temperature of the working area gradually increases, and the wind speed increases. PMV index and PPD index were used to evaluate the indoor comfort under the three air supply speeds. The air sup 3ply speeds of 1.5m/s and 2.3m/s can meet the requirements of indoor comfort. According to the distribution of personnel, 18 measuring points were set for measurement. The comparison between the simulation results and the measured results showed a consistent trend, which verified the feasibility and accuracy of Airpak for indoor thermal environment comfort analysis.

Automatic Compliance Check of Window-to-Wall Ratio Software Embeded Intelligent Algorithms in Revit Modeling

Window-to-Wall Ratio(WWR) is a crucial building envelope element that decides the air conditioning and lighting energy consumption in the building. Controlling WWR within a reasonable range is of great significance to building energy conservation. Due to the importance of WWR’s selection in Revit modeling, an automatic compliance check software in Revit Modeling is developed to ensure the WWR of Revit model within a reasonable range. The range is given in Design Standard for Energy Efficiency of Public Buildings (GB50189-2015,China). Based on the value range, the enumeration-based WWR compliance inspection software was developed in C# language and integrated into Revit to achieve compliance check on Revit model. Software testing was conducted for a certain office building in Shanghai, China. And Ecotect was used to analyze the thermal environment of unchecked model and checked model, respectively. The result shows that this software can automatically obtain the WWR of each facade of the current model, and determine whether it meets the range of the building location. When a facade does not meet the specification, it can be quickly and automatically adjusted to the appropriate range within the scope. By comparing the Ecotect thermal environment analysis results of unchecked and checked model, it is found that the heating and cooling loads are reduced after the model is checked with intelligent algorithms.

2018년 여름 집계구 단위의 상세 폭염취약성 원인 분석 : 구례군과 순창군을 대상으로

This study attempted to analyze the characteristics of heatwave damage in Gurye-gun and Sunchang-gun in 2018, at the height of a severe heatwave, and to identify detailed heatwave-vulnerable areas through spatial analysis. Data were assembled in units of aggregation zones for detailed spatial analysis. Shadow patterns, Sky view factor (SVF), and average radiation temperature distributions of 5m resolution were calculated using a solar radiation model for high-resolution thermal environment analysis. Individuals, environments, diseases, and weather factors that can affect heat wave damage were analyzed in units of census, and variables with spatial autocorrelation for Gurye-gun and Sunchang-gun were extracted through the model of Global Moran

Hybrid model combining multivariate regression and machine learning for the rapid prediction of interior temperatures affected by thermal diodes and solar cavities

Sustainable design often requires highly efficient building performance evaluations. This study proposed a hybrid model combining multivariate regression modelling (MRM) and machine learning modelling (MLM) for the rapid prediction of interior temperatures affected by heat pipe thermal diodes and solar cavities based on experimental data. A heat pipe thermal diode can promote unidirectional heat transmission from the solar cavity on the south side of our newly built experimental house to the indoor environment to increase the interior temperature and reduce the heating load in cold climates. Experimental data were collected and then imported, cleaned, and split according to MRM and MLM requirements, respectively. In MRM, linear multivariate formulas were generated according to the thermal diode's two different working conditions. In MLM, a machine-learning model was created and trained using the experimental data. The results our hybrid model produced were comprehensively evaluated via R-square, statistical discrepancies, and complex MRM analyses. The similarity between the prediction and experimental results clearly demonstrates our model's accuracy and efficiency. This research was an original attempt to integrate emerging computational tools and provide a means to perform highly efficient quantitative analysis of indoor thermal environments for environmental studies and sustainable designs in the early stages.

Pedestrians' behavior based on outdoor thermal comfort and micro-scale thermal environments, Austin, TX

Cities have faced rapid urbanization, which has changed the impact of the micro-thermal environment on residents' thermal comfort level. Therefore, planners need to understand the city's physical environment so they can identify and ameliorate the effects of the changing in micro-thermal environment. Researchers also need to identify and understand pedestrians' thermal comfort level in street canyons to determine which urban physical factors planners need to improve. This study aimed to observe how thermal comfort affects pedestrian behavior in micro-thermal environments and to determine which urban geometry factors influence pedestrians' thermal comfort. This study collected data in downtown Austin, TX using a mobile weather station, and analyzed the microclimate conditions experienced by pedestrians. A camera mounted on the weather station also allowed us to observe pedestrian behavior patterns. The results revealed that pedestrians tended to choose walking, sitting, and standing locations with high thermal comfort levels such as in the shade on the sidewalk. There was also some correlation between thermal comfort levels and pedestrian behavior patterns. The sky view factor (SVF) and tree canopy coverage ratio (TCR) were also correlated with pedestrians' thermal comfort. This study highlights the need for future research to develop a data collection method for efficient microscopic thermal environment research and a thermal environment estimation and analysis approach from a three-dimensional perspective.

Numerical Analysis of Thermal Environment in Deep Mining

To analyze heat effect in deep metal mines, it is crucial to understand the temperature field distribution around the mine tunnel. In this paper, a numerical model of the random mineral composition of the rock body is established based on finite element software to analyze the influence of the internal composition of the surrounding rock on the temperature field, and a numerical simulation model based on COMSOL finite element software is established based on the two heat exchange modes of heat conduction and heat convection in the surrounding rock. The results show that the numerical simulation results of a typical numerical simulation model using a single material are lower than the real situation; increasing the tunnel length does not increase the heat exchange efficiency between the rock wall and the air; increasing the wind velocity has a limited impact on the temperature field; the wind temperature more directly affects the mining surface; and the effect of wet air on the temperature field of the surrounding rock has a more substantial variation.

Development of a non-stationary thermal environment analysis method for combined convection and radiation air conditioning

Advanced thermal environment simulation technology has been developing rapidly in recent years. The thermal environment simulation tools used in thermal engineering can be broadly classified into energy simulations and computational fluid dynamics programs. The combination of these approaches allows the high-accuracy prediction of a non-stationary thermal environment in a continuous space. The main feature of the coupled analysis method is that the radiation is calculated using energy simulation, which reduces the analysis load and makes transient analysis possible. Here, a method was devised for predicting the thermal environment of air conditioners and radiant panels, and its accuracy was verified. By coupling the convective heat transfer coefficient, the maximum mean absolute error of the proposed method was calculated to be 0.674 [-], which is acceptable considering the variable environmental conditions. Although in the acceptable range, this error is attributable to computational fluid dynamics, which is a steady-state analysis and does not fully track the non-stationarity of the radiant panel because of its stop–start nature. The results of this analysis are comprehensive, with the convective heat transfer coefficient calculated using the input conditions for each wall. Regarding the energy simulation, when temperature stratification occurred near a surface, such as the ceiling, a small error was induced because the reference temperature was set to the bulk temperature. However, as the overall trend was captured by the analysis method, these minor errors were deemed acceptable. These results show that the proposed method can be applied to a range of applications, including office spaces.

Thermal environment analysis of enclosed dome with double-layered PTFE fabric roof integrated with aerogel-glass wool insulation mats: On-site test and numerical simulation

To study the thermal performance of an enclosed dome with double-layered PTFE membrane with aerogel-glass wool insulation mats, a comprehensive on-site test was carried out. Twenty-two wireless thermometers were used to monitor the temperature of key positions during a clear to cloudy day in summer. Solar irradiance was recorded as well. A numerical model was established to compare the thermal insulation property of this case and other three cases with different thermal insulations for double-layered membrane roof containing no extra insulation, peripheral wool glass insulation and all aerogel insulation. These cases only differ in the occupation area of thermal insulation materials laid on inner membrane. On-site test illustrates that the novel roof with aerogel- glass wool insulation can effectively prevent ambient radiation to pass through and render the stands insusceptible to the sunlight in regardless of the incidence angle. The temperature field of the dome is stratified and temperature only varies in vertical direction. According to numerical analysis, the current roof performs best in terms of thermal insulation property. This roof with combined insulation can reduce the average temperature difference of outdoor and indoor space by 7.7 ℃ while the value is merely 7.0 ℃, 5.9 ℃ and 4.8 ℃ for under the same environment condition.

Thermal environment analysis of landscape parameters of an urban park in summer - A case study in Suwon, Republic of Korea

Urban parks are becoming increasingly important for improving urban thermal environments. To investigate the thermal effects of landscape parameters of urban parks in summer, micrometeorological and human thermal sensation data were analyzed and compared. Data were collected at three fixed locations and twenty-four transient locations in Hyowon Park, Suwon, Republic of Korea. The chosen locations were surfaced with different materials and were exposed to different direct solar radiation by trees or artificial shading devices. It was found that human thermal sensations were influenced most by the mean radiant temperature. The physiological equivalent temperature was two levels lower in thermal perception in shaded locations than sunny ones. Therefore, the most effective method of reducing the mean radiant temperature and human thermal sensations in summer is to create large shaded spaces by building artificial shading devices such as pergolas and planting trees with a high crown density. Among the surface materials, cement bricks, grass-flagstones, and coconut mats created better human thermal environments than baked bricks, polyurethane, and granite. Based on these results, we provide a list of improvements that can be used to guide future policy and design of urban parks to improve the thermal environment of urban outdoor spaces.

The Overall Optimization and Design of the Long March 5 Launch Vehicle

The overall key technical research of the Long March 5 launch vehicle is introduced, such as the optimization design of large low temperature launch vehicle aerodynamic shape, attitude control design of swing booster engine, and large strap-on launch vehicle force and thermal environment analysis method, etc. The overall optimization technology scheme is advanced. New design and simulation technology are adopted and verified through the large ground test. Long March 5 achieves the 14-ton carrying capacity of GTO, and the overall technology reaches the international advanced level of similar launch vehicles. To meet the needs of deep space exploration missions, the overall technical research level of Long March 5 has been optimized and improved.

Optimal Air Conditioner Placement Using a Simple Thermal Environment Analysis Method for Continuous Large Spaces with Predominant Advection

The number of houses with large, continuous spaces has increased recently. With improvements in insulation performance, it has become possible to efficiently air condition such spaces using a single air conditioner. However, the air conditioning efficiency depends on the placement of the air conditioner. The only way to determine the optimal placement of such air conditioners is to conduct an experiment or use computational fluid dynamic analysis. However, because the analysis is performed over a limited period, it is difficult to consider non-stationarity effects without using an energy simulation. Therefore, in this study, energy simulations and computational fluid dynamics analyses were coupled to develop a thermal environment analysis method that considers non-stationarity effects, and various air conditioner arrangements were investigated to demonstrate the applicability of the proposed method. The accuracy verification results generally followed the experimental results. A case study was conducted using the calculated boundary conditions, and the results showed that the placement of two air conditioners in the target experimental house could provide sufficient air conditioning during both winter and summer. Our results suggest that this method can be used to conduct preliminary studies if the necessary data are available during design or if an experimental house is used.

Thermal environment analysis for TianQin

TianQin is a proposed space-borne gravitational wave observatory in high geocentric orbits, exposed to radiating heat sources in space. Due to the stringent thermal stability requirements from the key payloads, the analysis of space thermal environment is of great importance. This paper studies the incident thermal radiation onto the TianQin satellites from the Sun–Earth–Moon system. The solar constant fluctuation (SCF) and the Earth’s land-type features, based on the meteorological data, are considered, and an analytic function of lunar surface temperature is used. The analysis includes the solar radiation, the infrared radiation, and the albedo. The results are discussed in both time and frequency domains. The spectral analysis indicates that in the target frequency band of 0.1 mHz–1 Hz, the SCF plays a dominant role, and that the associated incident thermal disturbance is ∼5 W m−2 Hz−1/2 for TianQin, at the same level of the LISA in heliocentric orbits. In addition, the power spectra of the Earth’s and Moon’s heating fluctuation are given, both order-of-magnitude weaker than that of the solar radiation. The results may contribute to the thermal design and the noise analysis for TianQin.

Effect of human settlements on urban thermal environment and factor analysis based on multi-source data: A case study of Changsha city

Effect of human settlements on urban thermal environment and factor analysis based on multi-source data: A case study of Changsha city

Simulation and Analysis of Thermal Environment and Building Comparing Wetland Conditions in Banjarmasin-Indonesia and Saga-Japan

Climate change has actually happened, according to NASA data the surface temperature of the earth has increased significantly. The impact of rising earth surface temperatures causes erratic weather conditions, high rainfall and drought in the summer season. In August 2019, devastating forest fires in Indonesia caused smoke on the islands of Sumatera and Kalimantan. Meanwhile in Japan, flooding occurred in Saga prefecture due to high rainfall for several days. Environmental conditions between Indonesia and Japan are different but experience disasters at the same time. This study examines the real conditions of the thermal environment in Banjarmasin and Saga. The analysis results of the thermal environment and building thermal simulations in the two cities, there are similarities in thermal anomalies that tend to be high or extreme. In addition, thermal measurements are carried out in the summer of August and September. That month is summer conditions with a maximum temperature of 37°C, but in Saga it floods when the Banjarmasin experiences a drought. Building technology and accurate weather predictions from the government has been able to reduce the impact of disasters from climate change.

Energy audit and evaluation of indoor environment condition inside Assiut International Airport terminal building, Egypt

Large space buildings, such as airport terminal buildings, consume high energy due to the cooling demand; especially in hot arid climates; to achieve passenger thermal comfort. Evaluation of thermal environment and energy analysis inside airports is an important issue, in terms of reducing energy and controlling indoor environments. This work aims to analyze electrical energy consumption and the indoor environment of the terminal building at Assiut International Airport, Egypt as a case study. Indoor environmental conditions, and energy consumption with HVAC systems, were monitored inside five multiple functional zones within the terminal building (Departure hall, Public area, Duty-free hall, Gate, and Arrival hall) during summer (August 2017). The indoor environmental parameters monitored include: temperature, relative humidity, and illuminance. The results indicate the HVAC system consumed the largest portion (70%) of the overall building electricity demand, and the Energy Use Intensity (EUI) of ATZ terminal building is 300 kWh/m 2 /year. Also, indoor temperatures were found to be within the acceptable range of comfort, with a high energy consumption of 6,000,000 kWh for the year 2017. A significant reduction of monthly energy consumption was achieved based on increasing HVAC set temperature from 25 °C to 27 °C; a reduction equal to 24.5% of total energy consumption during the hot months. The results of this study help search for sustainable solutions for reducing energy consumption and improving passenger thermal comfort inside the terminal building (phase 2).

Measurements and Analysis of Thermal Environment of University Class Room for Optimal Control of Air Conditioning Equipment in Large Space

The authors conducted in the previous study that numerical experiments to inversely estimate the optimal air conditioning outlet temperature according to the target temperature. Numerical experiments showed the usefulness of the air conditioner control method using the SR method. However, when applying the SR method in real space, the accuracy of the SR method depends on the accuracy of CFD calculation. Therefore, in this study, as a preliminary step to the application of the SR method to the real space, the thermal environment of the real space was measured and compared with the CFD calculation results. Almost no horizontal temperature distribution was seen in the real space. From this result, it was found that there is a problem in creating the indoor space temperature distribution.

Case Study on Thermal Comfort with and Without Fill Using Thermal Environment Analysis for Building Envelopes with Thermally Complex Geometry

Case Study on Thermal Comfort with and Without Fill Using Thermal Environment Analysis for Building Envelopes with Thermally Complex Geometry

Dynamic energy modelling for analysis of the thermal and hygroscopic environment in a mechanically ventilated duck house

Thermal and hygroscopic environments inside a duck house are two of the most important factors directly related to their productivity and energy costs. However, few quantitative analyses of these environments have been performed. The objective of this study was to develop a dynamic energy model for the combined and real-time quantitative analysis of thermal and hygroscopic environments inside a mechanically ventilated duck house. To identify seasonal problems and develop the energy model, the internal and external environments of the duck house were first monitored via field experiments. Additionally, chamber experiments were conducted in a temperature- and humidity-controlled chamber to calculate the amount of evaporation from duck-house litter for incorporation of these data into the energy model. According to the environmental data measured in the field experiments and the results of the chamber experiments, the dynamic energy model of the duck house was developed using building energy simulation (BES). The BES model was validated by comparison of the BES-computed and field-measured data of the air temperature and relative humidity. The results showed errors of 1.71% and 4.33% for the air temperature and relative humidity, respectively. Finally, the validated BES model of the duck house was used to analyse the seasonal periodic and maximum energy loads. Furthermore, the high-temperature stress of the ducks in summer was also estimated for different space allowances.