局部热暴露对人体全身热反应的影响

介绍了有关局部热暴露的研究背景和重要进展,包括局部热暴露环境参数对局部热感觉的影响,局部热感觉对全身热反应的影响,不同部位的局部热感觉对全身热感觉影响的权重,以及相关的心理学和生理学研究现状。讨论了局部热暴露环境评价指标的选取和局部热暴露作用部位的选择,并指出了今后的研究方向。     

不同空调末端下人体局部热舒适对比研究

讨论了办公建筑空调系统中的辐射地板、辐射天花和对流换热3种不同的供冷末端在人体整体热感觉和局部热感觉方面的特征与差异。对3种不同供冷末端下的办公建筑进行现场热舒适调研测试,发现3种末端的中性温度相差较小,且辐射地板供冷系统的中性温度最高。通过对局部热感觉投票结果分析发现,3种末端的局部热感觉差异显著,辐射地板和对流换热供冷末端的局部热感觉有明显的“分层现象”。对流换热系统的上肢部位热感觉明显偏低,而辐射地板系统的下肢部位更容易产生冷感。对问卷中整体热感觉偏冷的人员分析发现,相比于对流供冷末端两种辐射末端的局部热感觉对整体热感觉的影响更显著。     

夏季局部送风非均匀热环境下人体热舒适研究

采用受试者主观实验的方法,分析了头部、前胸、后背、胳膊、手、腿和脚部单独进行局部送风冷刺激条件下,对整体和非刺激部位热感觉的影响,发现各部位热感觉之间存在多重共线性,采用主成分回归的方法分析了各部位对整体热感觉的影响。探讨了非均匀环境下整体热可接受度与整体热舒适及局部热可接受度之间的关系。结果表明,肢体末端的局部刺激仅能对其周围部位产生明显影响,对其他部位影响不大;躯干部位局部刺激能影响全身各个部位,从而导致身体热感觉的区域化差异;整体热舒适和整体热可接受度密切相关,局部热不可接受度在一定范围内时,不会影响整体热舒适性。     

通风方式对辐射空调房间人体热感觉及皮肤温度的影响

采用主观问卷与实验测试相结合的方法,探讨了辐射顶板+混合通风与辐射顶板+地板送风2种通风方式下房间内人体热舒适性的差异,分析了通风方式对人体热感觉及皮肤温度的影响。结果显示：不同通风方式下各部位皮肤温度的差异与相应部位热感觉的差异存在不一致情况;通风方式对受试者整体热感觉的影响较小,而对局部皮肤温度及局部热感觉的影响较大。     

局部热舒适性研究现状与展望

本文介绍了局部热舒适性的研究背景和主要进展,主要包括局部环境参数与局部热感觉的关系、局部环境参数与局部生理参数的关系、局部生理参数与局部热感觉的关系、不同部位的热感觉对整体热感觉的影响权重、局部热感觉对整体热反应的影响共5个方面,并且提出了今后的研究方向.     

局部热暴露对人体热反应的影响研究(2):不均匀热环境的评价

通过受试者主观投票的方法,对有局部热暴露存在的不均匀热环境的评价进行了实验研究。实验发现,全身热感觉不再是决定不均匀热环境可接受程度的唯一因素,热感觉不均匀性是另一个重要的影响因素。提出以部位间热感觉之差的最大值作为衡量热感觉不均匀程度的参数,基于此提出了新的不均匀热环境评价模型。模型显示,应用脸部热暴露可将夏季80%可接受的房间操作温度上限提高4.5℃。     

环境控制能力对人体热感觉影响的实验研究

对于室内人员心理上的差异是否能改善其自身的热感觉这一问题,目前学术界仍存在争议。本文设计了环境参数完全相同仅控制手段不同的心理学实验,受试者分别参加"无空调"、"免费空调"和"收费空调"工况的实验。研究表明,具有环境控制能力能显著改善受试者的热感觉和热舒适,如果人员具有对"温度"的控制能力,热感觉可以整体降低0.4～0.5,热舒适度可以提高0.3～0.4;付费削弱了控制能力对受试者热感觉和热舒适的改善作用,但在本实验设计的付费水平下,其影响并不显著。研究结果为环境控制中实现节能和舒适的统一提供了新的有效途径。     

低气压环境下空气流速对人体热感觉影响的研究

通过问卷调查的形式,研究了20名处于不同大气压力环境中受试者的热感觉和风速期望随空气流速变化的情况,进而分析了不同大气压力环境中,空气流速对用风速期望进行评价的吹风感和人体平均热感觉(MTS)的影响.研究表明:低气压环境下人体对空气流速变化的感觉不如常压下敏感,人体在较高温度下对风速变化的感觉不如较低温度下敏感.在20～22 ℃时,低气压环境下微风速(<0.2 m/s)范围内的风速变化对身着厚重衣物的受试者的热感觉影响十分微小.     

灯暖浴霸环境下浴室人员热感觉研究

为了解夏热冬冷地区冬季灯暖浴霸的使用效果和人员在浴霸环境下的局部及整体热感觉,进行了浴霸环境下浴室人员热感觉研究.测定了浴室的环境参数,利用PMV模型计算预测投票值,并与人员实际热感觉投票值进行了对比分析.结果表明:浴霸开启后,浴室中垂直温度梯度增大,PMV值增大.人员整体热感觉始终大于0,除头部热感觉变化不大外,各部位热感觉变化趋势相似,且暖灯开启盏数越多,整体和局部热感觉投票值越大.通过回归分析得出,头部,手臂和腿部对整体热感觉的影响较为显著;浴霸可以满足人员想要改善浴室中寒冷感的需求;PMV模型无法准确预测该环境下人员的热感觉.     

侧墙热辐射对人体热舒适的影响

通过人工气候室实验,以24名身着热阻为0.6 clo夏季室内服装的受试者为研究对象,研究了在中性空气温度(26℃)、侧墙热辐射条件下不同暴露时间对人体热反应与热舒适的影响。结果表明:随着受试者在不均匀辐射环境中暴露时间的增加,受试者热感觉逐渐降低并趋近中性,热舒适度和热可接受度逐渐增大,平均皮肤温度无显著变化,心率略有降低;中性环境温度下,暴露时间为60、120、180 min时,5%局部热不舒适的不对称辐射温度限值分别为1.7、1.9、4.5℃。得到了不同部位热感觉、热舒适对全身热感觉、热舒适的影响权重,建立了适用于中性环境温度、侧墙热辐射环境下的人体热感觉和热舒适评价模型。     

Effect of local exposure on human responses

At room temperatures ranging from 28 to 35 °C, the three sensitive body parts face, chest and back were exposed to local cooling airflow, whose temperatures ranged from 22 to 28 °C. Dressed in shorts, 30 randomly selected male subjects were exposed to each condition for 30 min and reported their local thermal sensations of all body parts, overall thermal sensation and thermal acceptability on voting scales at regular intervals. It was shown that local exposure affected local thermal sensations of the unexposed body parts significantly, based on which a new influencing factor method was proposed. Influencing factor and weighting factor for each body part are unaffected by room or cooling air temperatures under steady state and the predictive model of overall thermal sensation was obtained using influencing and weighting factors. Taking the maximum thermal sensation difference between body parts to represent non-uniformity of thermal sensation, a new assessment model for non-uniform thermal environment was proposed. The model shows that the upper boundary of the acceptable room temperature range can be shifted from 26 to 30.5 °C while face cooling is provided.     

Overall thermal sensation,acceptability and comfort

The relationships between overall thermal sensation, acceptability and comfort were studied experimentally under uniform and non-uniform conditions separately. Thirty subjects participated in the experiment and reported their local thermal sensation of each body part, overall thermal sensation, acceptability and comfort simultaneously. Sensation, acceptability and comfort were found to be correlated closely under uniform conditions and acceptable range ran from neutral to 1.5 (midpoint between ‘Slightly Warm’ and ‘Warm’) on thermal sensation scale and contained all comfortable and slightly uncomfortable votes on thermal comfort scale. Under non-uniform conditions overall thermal acceptability and comfort were correlated closely. However, overall thermal sensation was apart from the other two responses and non-uniformity of thermal sensation was found to be the reason for the breakage. Combining the effects of overall thermal sensation and non-uniformity of thermal sensation, a new thermal acceptability model was proposed and the model was testified to be applicable to uniform and non-uniform conditions over a wide range of whole body thermal state from neutral to warm.     

Thermal sensation and comfort models for non-uniform and transient environments, part III: Whole-body sensation and comfort

A three-part series presents the development of models for predicting the local thermal sensation (Part I) and local thermal comfort (Part II) of different parts of the human body, and also the whole-body sensation and comfort (Part III) that result from combinations of local sensation and comfort. The models apply to sedentary activities in a range of environments: uniform and non-uniform, stable and transient. They are based on diverse findings from the literature and from body-part-specific human subject tests in a climate chamber. They were validated against a test of automobile passengers. The series is intended to present the models’ rationale, structure, and coefficients, so that others can test them and develop them further as additional empirical data becomes available.A) The whole-body (overall) sensation model has two forms, depending on whether all of the body's segments have sensations effectively in the same direction (e.g warm or cool), or whether some segments have sensations opposite to those of the rest of the body. For each, individual body parts have different weights for warm versus cool sensations, and strong local sensations dominate the overall sensation. If all sensations are near neutral, the overall sensation is close to the average of all body sensations.B) The overall comfort model also has two forms. Under stable conditions, people evaluate their overall comfort by a complaint-driven process, meaning that when two body parts are strongly uncomfortable, no matter how comfortable the other body parts might be, the overall comfort will be near the discomfort level of the two most uncomfortable parts. When the environmental conditions are transient, or people have control over their environments, overall comfort is better than that of the two most uncomfortable body parts. This can be accounted for by adding the most comfortable vote to the two most uncomfortable ones.     

均匀和不均匀热环境下热感觉、热可接受度和热舒适的关系

对30名受试者采用问卷调查的方式,研究了均匀热环境和不均匀热环境下人体全身热感觉、热可接受度和热舒适的关系。结果显示,在均匀热环境下,全身热感觉、热可接受度和热舒适具有较强的线性相关关系,可接受范围涵盖了(0,1.5)的热感觉投票和"舒适"与"稍有不适"标度范围内的热舒适投票;在不均匀热环境下,全身热可接受度与热舒适密切相关,而全身热感觉与热可接受度和热舒适出现分离,热感觉不均匀度是其原因。综合考虑全身热感觉和热感觉不均匀度的影响,提出了综合评价模型。经验证,该模型适用于全身热状态为中性偏热的均匀和不均匀热环境。     

Models of human thermoregulation and the prediction of local and overall thermal sensations

This study aims at comparing the predictions of skin temperature from different models of human thermoregulation and investigating the currently available methods for the prediction of the local and overall thermal sensations. In this paper, the Fiala model, the University of California, Berkeley (UCB) thermoregulation model and a multi-segmental (MS) Pierce model were tested against recently measured data from the literature. The local and overall thermal sensations were predicted for different room conditions, obtained from a recent experimental study, using the UCB comfort model coupled with the MS-Pierce model. The overall thermal sensation was further predicted using three other models. The predictions were then compared with the subjective votes obtained from that study. The equivalent temperature approach was also investigated based on the same experimental study. The results show comparisons of the predicted skin temperature by the thermoregulation models, under steady state and dynamic conditions, with the measured data as well as the predictions of the thermal sensations from the different models.     

Thermal sensation and comfort models for non-uniform and transient environments, part II: Local comfort of individual body parts

A three-part series presents the development of models for predicting the local thermal sensation (Part I) and local comfort (Part II) of different parts of the human body, and also the whole-body sensation and comfort responses (Part III). The models predict these subjective responses to the environment from thermophysiological measurements or predictions (skin and core temperatures). The models apply to a range of environments: uniform and non-uniform, transient and stable. They are based on diverse results from literature and from body-part-specific human subject tests in a climate chamber. They were validated against a test of passengers in automobiles. This series is intended to present the rationale, structure, and coefficients for these models so that others can test them and develop them further as additional empirical data becomes available. The experimental methods and some measured results from the climate chamber tests have been published previously.Part II describes a thermal comfort model with coefficients representing 19 individual local body parts. For each part, its local comfort is predicted from local and whole-body thermal sensations. These inputs are obtained from the sensation models described in Part I and III, or from measurements.     

Local thermal sensation and comfort study in a field environment chamber served by displacement ventilation system in the tropics

This paper presents a study of local thermal sensation (LTS) and comfort in a field environmental chamber (FEC) served by displacement ventilation (DV) system. The FEC, 11.12 m (L)×7.53 m (W)×2.60 m (H), simulates a typical office layout. A total of 60 tropically acclimatized subjects, 30 male and 30 female, were engaged in sedentary office work for 3 h. Subjects were exposed to three vertical air temperature gradients, nominally 1, 3 and 5 K/m, between 0.1 and 1.1 m heights and three room air temperatures of 20, 23 and 26 °C at 0.6 m height. The objective of this study is to investigate the mutual effect of local and overall thermal sensation (OTS) and comfort in DV environment. The results show that in a space served by DV system, at OTS close to neutral, local thermal discomfort decreased with the increase of room air temperature. The OTS of occupants was mainly affected by LTS at the arm, calf, foot, back and hand. Local thermal discomfort was affected by both LTS and OTS. At overall cold thermal sensation, all body segments prefer slightly warm sensation. At overall slightly warm thermal sensation, all body segments prefer slightly cool sensation.     

Local thermal sensation modeling—a review on the necessity and availability of local clothing properties and local metabolic heat production

Local thermal sensation modeling gained importance due to developments in personalized and locally applied heating and cooling systems in office environments. The accuracy of these models depends on skin temperature prediction by thermophysiological models, which in turn rely on accurate environmental and personal input data. Environmental parameters are measured or prescribed, but personal factors such as clothing properties and metabolic rates have to be estimated. Data for estimating the overall values of clothing properties and metabolic rates are available in several papers and standards. However, local values are more difficult to retrieve. For local clothing, this study revealed that full and consistent data sets are not available in the published literature for typical office clothing sets. Furthermore, the values for local heat production were not verified for characteristic office activities, but were adapted empirically. Further analyses showed that variations in input parameters can lead to local skin temperature differences (?T_skin,loc = 0.4–4.4°C). These differences can affect the local sensation output, where ?T_skin,loc = 1°C is approximately one step on a 9‐point thermal sensation scale. In conclusion, future research should include a systematic study of local clothing properties and the development of feasible methods for measuring and validating local heat production.     

Thermal effect of temperature gradient in a field environment chamber served by displacement ventilation system in the tropics

The effect of vertical air temperature gradient on overall and local thermal comfort at different overall thermal sensations and room air temperatures (at 0.6 m height) was investigated in a room served by displacement ventilation system. Sixty tropically acclimatized subjects performed sedentary office work for a period of 3 h during each session of the experiment. Nominal vertical air temperature gradients between 0.1 and 1.1 m heights were 1, 3 and 5 K/m while nominal room air temperatures at 0.6 m height were 20, 23 and 26 °C. Air velocity in the space near the subjects was kept at below 0.2 m/s. Relative humidity at 0.6 m height was maintained at 50%. It was found that temperature gradient had different influences on thermal comfort at different overall thermal sensations. At overall thermal sensation close to neutral, only when room air temperature was substantially low, such as 20 °C, percentage dissatisfied of overall body increased with the increase of temperature gradient. At overall cold and slightly warm sensations, percentage dissatisfied of overall body was non-significantly affected by temperature gradient. Overall thermal sensation had significant impact on overall thermal comfort. Local thermal comfort of body segment was affected by both overall and local thermal sensations.