Radiant heat and thermal comfort in vehicles

Infrared-reflective (IRR) treatment of automotive glass has been shown to reduce air temperature in vehicle cabins, thereby increasing fuel economy and occupant comfort. Its effect on radiant heat, however, may augment these benefits. In this study, the hypothesis that radiant heat affects subjective comfort ratings in a vehicle was tested. IRR films were systematically applied to the driver-side window of an outdoor stationary vehicle. In Phase 1, cabin air temperature was controlled while participants rated their thermal comfort. In Phase 2, air temperature was adjusted according to participants' responses. Results in Phase 1 showed that the IRR treatment improved thermal comfort on the left forearm, which was exposed to direct solar irradiance, but not whole-body thermal comfort. In Phase 2, participants indicated that they were comfortable at a higher air temperature (mean of 2.5 degrees F [1.4 degrees C]) with the IRR treatment than in the untreated condition. The results indicate that reducing radiant heat via IRR treatment affects subjective assessments of thermal comfort and allows occupants to maintain the same level of comfort in a warmer vehicle cabin. Applications of this research include future implementations of IRR treatment on automotive glass that may lead to greater fuel economy savings and occupant comfort than have previously been estimated.     

The assessment of heat radiation

Approximately 900 climatic chamber experiments were performed with 16 male subjects to study the thermal strain at climates including increased heat radiation. Based on the reactions of heart rate, rectal temperature and sweat rate, a heat stress index was developed for the assessment of climates with effective heat radiation intensities up to 1400 W m⁻². The index considers different combinations of dry air temperature (5–55°C), globe temperature (25–76°C), mean radiant temperature (25–160°C), air velocity (0.5–2.0 m s⁻¹), clothing, physical work load and directions of radiation and air flow.

The index integrates combinations of the variables producing the same degree of thermal strain into a single value. This value indicates the temperature of the physiologically equivalent climate in which air and radiant temperature are equal. It can be determined from a simple formula or from correspondent graphs.

In comparison, the international recommended heat stress indices are less capable to evaluate heat radiation correctly. The incorporation of the new partial index into the used indices may improve substantially their physiological validity in the assessment of climates with radiant heat stress.

Relevance to industry

The goal of this paper is to provide an improved assessment of thermal stress in working environments in which heat radiation is an important heat stress factor.     

红外成像仪在IT信息机房中的应用

介绍了将红外热成像仪用到信息机房机柜及设备的温度监测中,它可以实现对单点设备的进风口、出风口温度分布情况进行直观查看,形成局部区域温度分布图谱,与机房整体温度监测,利用测温枪进行点温度测量结合,可以形成对机房整体温度、机柜温度、设备温度以及线路温度的从点到面的全方位温度监测,解决单点设备温度监测效果差的问题,从而保证信...     

A guide to thermal comfort

This guide provides a simple design procedure for dealing with the requirements for a comfortable thermal environment. From the expected activity level and clothing insulation of the people concerned, a subjective temperature is calculated which will provide thermal comfort. This subjective temperature is a combination of physical parameters of the environment, ie, air and mean radiant temperatures, and air speed. A heating system must be designed to that the parameters combine to give the optimum subjective temperature. The guide also considers other possible sources of discomfort, and gives acceptable limits for them.     

Satellite-derived urban heat islands from three coastal cities and the utilization of such data in urban climatology

Abstract

NOAA AVHRR satellite infra-red data are used to display the surface radiant temperature heat islands of Vancouver, British Columbia, Seattle, Washington, and Los Angeles, California. Heat island intensities are largest in the day-time and in the warm season. Day-time intra-urban thermal patterns are strongly correlated with land-use; industrial areas are warmest and vegetated, riverine or coastal areas are coolest. Nocturnal heat island intensities and the correlation of the surface radiant temperature distribution with land use are less. This is the reverse of the known characteristics of near-surface air temperature heat islands. Several questions relating to the interpretation and limitations of satellite data in heat island analysis and urban climate modelling are addressed.     

Physiological strains in hot-humid conditions while wearing disposable protective clothing commonly used by the asbestos removal industry

Abstract

The purpose of this study is to investigate workers' responses to work in hot-humid conditions while wearing protective clothing commonly used by the asbestos removal industry, and to evaluate the effects of resting between work bouts in a cool environment on the physiological strain. Seven male students wearing impermeable protective clothing and air masks were exposed to the following conditions for 100 min on separate days: (1) hot conditions (35°C/85%RH), (2) cool conditions (20°C/85%RH), and (3) hot/cool conditions (working in hot conditions and resting in cool conditions). After 12 min rest, the subjects worked on an ergometer (70 Watts) for 18 min. This experimental schedule was repeated three times under each environmental condition. Rectal temperature (T_π), heart rate (HR), sweat rate (SR) and discomfort sensation were recorded. Two of the subjects were not able to complete the experiment in hot conditions. The increases in T_π and HR with time were not found in cool conditions. Although T_π increased in hot/cool conditions, it was almost half of that in hot conditions. Since HR did not return to the pre-work level during recovery in hot conditions, HR during work was accompanied by increases in HR at pre-work. HR during work in hot/cool conditions was higher than that in cool conditions, HR at pre-work, however, was almost the same as that in cool conditions because of rapid recovery. The means of SR in hot and hot/cool conditions were five and four times greater than that in cool conditions, respectively. Discomfort sensation was improved by resting in cool conditions either at rest in cool conditions or during work in hot conditions. The rate of body heat storage that was calculated at the end of each work and recovery period showed that it was positive even in recovery under the hot conditions. It also presented a significant negative phase in recovery under the hot/cool conditions. Thermal stress was linked to work in protective clothing in hot-humid environments. However, the physiological strains were dramatically ameliorated by resting between work periods in a cool environment. The idea of a ‘cool room’ inside the workplace, so to reduce thermal stress, is proposed.     

The influence of heated or cooled seats on the acceptable ambient temperature range

In 11 climate chamber experiments at air temperatures ranging from 15 to 45 degrees C, a total of 24 subjects, dressed in appropriate clothing for entering a vehicle at these temperatures, were each exposed to four different seat temperatures, ranging from cool to warm. In one simulated summer series, subjects were preconditioned to be too hot, while in other series they were preconditioned to be thermally neutral. They reported their thermal sensations, overall thermal acceptability and comfort on visual analogue scales at regular intervals. Instantaneous heat flow to the seat was measured continuously. At each ambient room temperature, the percentage dissatisfied was found to be a second-order polynomial function of local heat flow. Zero heat flow was preferred at an air temperature of 22 degrees C and the heat flow that minimized the percentage dissatisfied was found to be a single linear function of air temperature in all conditions. The analysis indicates that providing optimal seat temperature would extend the conventional 80% acceptable range of air temperature for drivers and passengers in vehicle cabins by 9.3 degrees C downwards and by 6.4 degrees C upwards.     

The influence of heated or cooled seats on the acceptable ambient temperature range

In 11 climate chamber experiments at air temperatures ranging from 15 to 45°C, a total of 24 subjects, dressed in appropriate clothing for entering a vehicle at these temperatures, were each exposed to four different seat temperatures, ranging from cool to warm. In one simulated summer series, subjects were preconditioned to be too hot, while in other series they were preconditioned to be thermally neutral. They reported their thermal sensations, overall thermal acceptability and comfort on visual analogue scales at regular intervals. Instantaneous heat flow to the seat was measured continuously. At each ambient room temperature, the percentage dissatisfied was found to be a second-order polynomial function of local heat flow. Zero heat flow was preferred at an air temperature of 22°C and the heat flow that minimized the percentage dissatisfied was found to be a single linear function of air temperature in all conditions. The analysis indicates that providing optimal seat temperature would extend the conventional 80% acceptable range of air temperature for drivers and passengers in vehicle cabins by 9.3°C downwards and by 6.4°C upwards.     

Analysis of Meticulous Features of Urban Surface Temperature based on UAV Thermal Thermography

Taking a university campus in Jiangning District of Nanjing as the study area，we used an Unmanned Aerial Vehicle (UAV) mounted with a thermal infrared imager to map the land surface temperature of the study area for analysis of thermal variance and its change over different typical urban surface patterns.6 typical urban underlying surfaces (water，shrubs，grass，brick pavement，marble pavement and asphalt pavement) were identified in the study area.Thus，the objective of the study is to analyze the variation of the obtained land surface temperature among the surface patterns in the study area and to reveal the detailed characteristics of the LST changes under different weather conditions within a day and a month.The estimation of sensible heat release was conducted to quantitatively describe the fine characteristics of the surface temperature of different underlying surfaces.The influencing factors of surface temperature changes were investigated by correlating surface temperature with meteorological factors.The results showed that under different weather conditions，there were differences in the characteristics of surface temperature and sensible heat release on underlying surfaces.In sunny days，the diurnal variation of different underlying surfaces fluctuated greatly，the temperature of asphalt pavement was relatively high，and the sensible heat release was the largest，which had the greatest impact on the thermal environment，followed by the marble and brick pavement.The water and shrub almost had no sensible heat release during the day，and the remission effect on the thermal environment was obvious.In cloudy days，the diurnal variation of surface temperature on different underlying surfaces was not obvious and the artificial was still the main body of sensible heat release.Referring to meteorological factors，the solar radiation and the air temperature were positively correlated with the surface temperature of the underlying surface which had a warming effect on the underlying surface.The air humidity was negatively correlated with the temperature of the underlying surface，which played a role of cooling the land surface.This research will provide a new idea and method for the study of urban micro\|thermal environment and a theoretical basis for the research of urban micro-thermal environment based on remote sensing. 〖HT〗〖ST〗〖HJ〗〖WT〗〖JP〗〖LM〗 〖GK2!2〗     

漆包机烘炉热能平衡模糊控制系统设计与实现

漆包机烘炉温度系统的实时性和稳定性,关系到漆包线产品质量。针对漆包机烘炉热能系统特点,提出了一种的漆包机烘炉的热能平衡模糊控制系统,该系统提出了模糊热能平衡控制、PID温度控制结合的漆包机温度控制系统的设计思路。针对漆包机烘炉结构和系统特性进行研究,根据热能平衡方程建立漆包机烘炉系统的温度模型;利用热力学相关理论知识分析热能的输入输出的主要组成部分,计算烘炉的总热量;并提出热能平衡模糊控制系统原理流程图,设计相关的软、硬件模块加以实现。试验与测试表明,该热平衡系统为烘炉内各加热区域的温度调节提供了可靠保障;使烘炉的温控能够自适应环境温度的变化;热平衡系统以节约电能为准则,最大限度地减少电能消耗,提高产能比。     

遥感数据融合下的雄安新区NPP时空格局分析

高时空分辨率数据对实现植被生产力动态监测和生态环境评估具有重要意义。以雄安新区为研究区,基于改进的ESTARFM融合模型构建高时空分辨率NDVI数据集,结合改进的CASA模型,模拟和分析了2000~2018年区域植被NPP的时空变化特征,并探讨气温与降水对NPP的影响。结果表明：①改进的ESTARFM融合模型预测结果性能较好;②研究区NPP的分布在空间上与土地覆被密切相关;③NPP在2000~2018年的变化趋势并不显著,但有明显的阶段性波动特征,主要是受到城镇化发展与农业技术水平提高等作用的影响;④由于区域气候的变化引起植被水分胁迫,降水对植被NPP的影响较气温更为显著。该研究能为雄安新区及其他区域的可持续发展评估提供一定的科学依据和借鉴意义。     

2130退火炉加热段控制

本文以轧钢厂连退2130退火炉为研究对象,介绍了退火炉加热段的工艺布置、控制系统组成。分析了加热段的控制方式和工作特点。阐明了加热控制系统的实现方法。实践证明这种加热控制具有精度高、控制灵活、操作强度低等特点。     

基于计算机视觉的车辆违章轧线监管系统研究

针对目前车辆违章轧线监管系统监控范围小和准确率有待提高的问题,为了尽可能扩大监控范围和提高准确率,本文提出一种基于高速球型摄像机的主动智能车辆轧线监管方法。首先,根据实际需求设计硬件系统和软件系统,并利用高速球机的机动性,提出静态检测和动态抓拍相结合的方法,以扩大监管范围。此外,针对准确率不高的问题,提出两步轧线检测算法,即根据前景最小外接矩形框初步判断是否轧线,再进一步通过轧线附近的区域统计前景比例来精确判断,从而提高轧线检测的准确率和抗干扰能力。实验结果表明,相比于传统轧线检测系统,本文设计的系统监控范围扩大了1倍,并且检测准确率提高了21.1%,实现了大范围内对违章轧线车辆的有效监管。     

热红外遥感在内蒙古多伦县玉米良种适宜积温地块调查中的应用

论证了热红外遥感技术探测种植玉米良种适宜积温地块的物理依据,探讨了实现这一目的的技术途径与方法,以监督彩色密度分割后的热红外辐射温度等级分布图为基础,建立了辐射温度与相应积温的对应关系,并结合多伦县的实际情况利用遥感方法对该区玉米良种适宜地块的分布进行了分析,为多伦县寻找种植玉米良种适宜积温块提供了科学的依据。2000年多伦县推广种植情况表明该技术方法具有良好的应用效果。     

Feedforward control of glass mold colling

In the manufacture of glass containers, good temperature regulation of the forming molds is essential for a high production yield. However daily and hourly temperature fluctuations of the cooling air, drawn from outside the glass plant, upsets the temperature stability. A 1°F change in the cooling air results in a 1.4°F change in the formed glass if air flow is unchanged. Since continuous mold or glass temperature measurements are impractical under production conditions, a feedforward control system, based upon a mathematical model of mold cooling and supported by experimentation, was designed to modulate the air flow to maintain mold cooling conditions. The design is implemented using a pressure controller manipulating a valve (or blower louver), with the controller setpoint computed from the air temperature. If the computed pressure exceeds a preset limit, due to temperature extremes, an override control function changes the glass feeder temperature controller setpoint and/or the machine speed instead of pressure. In the first installation, the feedforward control system paid for itself in several days. Since then, two years of operation at one plant has shown that two containers with production yields previously at 80–82% increased an average 7.6% and six containers with production yields at 90–92% increased an average 2.3%.     

Simulating canopy temperature for modelling heat stress in cereals

Crop models must be improved to account for the effects of heat stress events on crop yields. To date, most approaches in crop models use air temperature to define heat stress intensity as the cumulative sum of thermal times (TT) above a high temperature threshold during a sensitive period for yield formation. However, observational evidence indicates that crop canopy temperature better explains yield reductions associated with high temperature events than air temperature does. This study presents a canopy level energy balance using Monin–Obukhov Similarity Theory (MOST) with simplifications about the canopy resistance that render it suitable for application in crop models and other models of the plant environment. The model is evaluated for a uniform irrigated wheat canopy in Arizona and rainfed maize in Burkina Faso. No single variable regression relationships for key explanatory variables were found that were consistent across sowing dates to explain the deviation of canopy temperature from air temperature. Finally, thermal times determined with simulated canopy temperatures were able to reproduce thermal times calculated with observed canopy temperature, whereas those determined with air temperatures were not.     

基于LabVIEW的滚动接触疲劳试验测控系统

针对现有疲劳寿命试验机存在异常停机、无远程监控和试验数据保存不完整等问题,对其基于LabVIEW的测控系统进行了改进,增加了智能停机、远程监控、数据分块保存等功能模块,并对改进后的测控系统进行了基于滚动轴承磷化处理项目的试验测试,试验结果表明:改进后的测控系统解决了上述问题,在实现其基本功能的同时提高了试验效率、扩展了试验机功能,提高了试验机的测控性能,为滚动接触疲劳寿命的研究提供了有力的技术支持。     

笔记本电脑散热结构优化设计

分析了某款基于国产中央处理器的自主可控笔记本电脑散热较差的主要因素,并针对关键因素进行优化设计。通过对散热模组、风道和转轴盖的优化设计提高了笔记本电脑的整体散热性能。温度测试实验数据表明:在25℃工作环境中,机器满负荷工况运行时,优化后的笔记本电脑各测试点的温度均有明显降低,散热有较大的改善,C壳键盘最热区域温度为35℃,用户体验感良好。     

加尔各答市地表温度与不透水面比例季相相关性研究

城市化的显著特征是自然地表不断被热容量大的不透水面取代,进而造成城市热岛效应和严重的城市生态问题。孟中印缅经济走廊是古代南方丝绸之路的重要路段和“一带一路”建设的重要战略通道,加尔各答市是孟中印缅经济走廊印度境内的重要节点城市,战略地位重要,对其城市化进程及与地表温度相关性研究对孟中印缅经济走廊印度段建设具有重要的借鉴意义。传统地表温度与不透水面的相关性研究主要以年为时间尺度,较少关注城市不同季相地表温度与不透水面的相关性及其差异。以热带季风气候的季相区分为依据,基于旱季、雨季和凉季3个季相的Landsat 8影像反演了加尔各答市地表温度和不透水面比例,定量研究两者的关系,探讨了地表温度与不透水面比例的季相相关性。结果表明：①研究区内,低温和高温空间分布相对比较集中,高温区域集中在建成区,而低温主要分布在茂密植被覆盖区和水体区域;②加尔各答市从旱季到雨季再到凉季热岛效应程度总体呈下降趋势,旱季时城市热岛效应最强,凉季时城市热岛效应最弱;③每个季相,地表温度与不透水面比例都呈正相关,地表温度随着不透水面比例增加均呈现先快速上升,后缓慢增加,最后急剧增加的趋势,其中旱季时地表温度增长最快,雨季时地表温度增长次之,凉季时地表温度增长最慢。加尔各答市热环境研究将对孟中印缅经济走廊印度段城市热环境背景及生态效应认知等方面产生积极意义。