The human body has a unique mechanism for perceiving surrounding temperatures. When an object is in contact with the skin, we do not feel its temperature. Instead, we feel the temperature change that is caused on our skin by that object. The faster the heat is transferred, the more intense the thermal sensation is. In this dissertation, a new dynamic thermal display method, where different rates of warm and cold are applied on the skin to generate a unique sensation, is presented. The new method can be related in a wide range of applications including thermal haptics and virtual reality. To understand the perception of temperature and the general thermal state of the human body, the first aspect of this dissertation focuses on investigating the interaction between temperature change and perception on a large scale. Three field surveys were conducted inside airconditioned buildings to investigate the change in the thermal state and temperature perception of occupants when the room temperature changes. The results showed that the participants’ prediction of constant operating temperature was poor, however, their prediction was significantly improved when temperature changes were presented. In order to more accurately investigate the perception of temperature on the skin, a new thermal display method using multiple-channel thermal actuators was developed. The principle of this method is to apply slow and fast rates of temperature change simultaneously on the skin. The slowly changing temperatures are below the perceptual threshold of the thermal receptors, therefore will not be detected whereas the quickly changing temperatures are above the perceptual threshold, hence, will be detected. The idea here is to keep the average surface temperature of the skin constant, however a person will perceive a sensation of continuous cooling. This method was tested through a series of experiments, and the results showed that it is capable of generating a continuous cooling sensation without changing the average temperature of the stimulation area. Multiple variations of this method were tested including different heating and cooling rates of change, different skin locations and patterns of stimuli. Also, a continuous warming was generated using similar concept. To further investigate the temperature distribution that is caused by this method and its effect on the skin, a computational simulation was conducted. An approximate model of the skin was used to monitor its surface temperature and record the temperatures in the stimulation area when the continuous cooling method is applied. The results of the simulation showed that the temperature under the surface of the stimulation area was affected by the continuous cooling method that was applied on the skin model, however this method did not affect the average surface temperature of the skin. These findings may later determine the efficiency and intensity of the method of continuous cooling, and allow us to investigate different technically challenging variations of this method.

Thermal sensation is one of the most dynamic stimulus-response systems in the human body. It is relied upon for safety, comfort and general equilibrium of the human body. Thermal sensation is dependent upon many variables such as area of effected skin, rate of temperature change and location of stimulation. It has been shown that certain rates of change can intensify the sensation of heating or cooling. Conversely, sufficiently low rates of change can go undetected by the skin. As such, the thermal response system can be manipulated by the proper combination of applied hot and cold stimuli. Previous research has shown that through precise application of an asymmetrically heated and cooled thermal display, a sensation of constant cooling can be perceived. This thesis seeks to (1) explore the heat flux characteristics of the thermal display through the use of computer simulations, (2) test a hypothesis about the relationship between thermal sensation and heat flux and (3) examine modifications of the thermal display patterns with the intention of producing more intense thermal sensations. To characterize the heat flux patterns produced by the thermal display, finite element simulations, performed using commercially available software ANSYS©. Simulations are conducted on individual heating and cooling rates to examine the expected values of heat flux as temperatures approach and diverge from skin temperature. Evaluated in the cylindrical coordinate system (axial, angular and radial), the simulations showed a slight nonlinear heat flux generation at the beginning of heating and cooling, but after the initial transient period, this gave way to a strong linear generation of increasing or decreasing heat flux. Simulations were performed that represent the physical experiments implemented in pre- vious research. These simulations were done in two parts: the first examines a small subregion with finer detail on the area between heating and cooling stimuli, the second is a larger scale examination of the heat flux profile of the thermal display. Initially it was observed that directly under the thermal stimulus, in the radial direction, the heat flux was almost perfectly in-phase with the oscillation of temperature whereas between the stimuli, it was nearly 180 degrees out of phase. The heat flux in the axial and angular directions under the thermal stimulus were negligible. Additionally, between stimuli, the values were nearly 180 degrees out of phase with temperature. Additionally, it was observed that the heat flux profiles for all patterns used in the thermal display were approximately identical. From the data gathered by the simulations in conjunction with the thermal sensation data from previous research, a linear relationship is hypothesized that relates these two quantities. This relationship was then used to determine the theoretical thermal sensations of newly developed thermal display patterns in order to determine which are best suited for future physical experimentation.

Orientador: João Roberto Gomes de Faria / Resumo: O modo como são projetados e ocupados os espaços de trabalho interferem tanto em como as pessoas se sentem como em seu desempenho. Oferecer um ambiente interno confortável é necessário para que seus ocupantes alcancem um melhor desempenho. Assim, um dos principais fatores para que um ambiente possua qualidade interna é que este seja termicamente confortável. Neste sentido, as escolhas arquitetônicas têm a capacidade de proporcionar experiências, sejam elas físicas, funcionais ou psicológicas, capazes de influenciar na percepção térmica de seus ocupantes. Por sua vez, os usuários de salas individuais têm papel fundamental no ajuste dos sistemas que visam estabelecer condições de conforto térmico de suas salas. Sendo assim, o objetivo do trabalho foi verificar, através de uma análise exploratória, como o uso de estratégias bioclimáticas para a obtenção do conforto ambiental por usuários de escritórios individuais é capaz de influenciar a sensação térmica. Para isto, um estudo de caso foi realizado com os docentes e suas salas de escritórios individuais dos quatro prédios de departamento da Faculdade de Arquitetura, Artes e Comunicação (FAAC) da Unesp, Campus de Bauru: Design; Arquitetura, Urbanismo e Paisagismo; Ciências Humanas; Artes e Representação Gráfica. Foi adotado na pesquisa um método misto com avaliações quantitativas e qualitativas através, respectivamente, de simulação computacional e aplicação de questionários. Os resultados mostraram que usuários de escritórios in... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: The way workspaces are designed and occupied interfere with how people feel and in their performance. Providing a comfortable indoor environment is necessary for their occupants to achieve better performance. Thus, one of the main factors for the quality of an environment is that it is thermally comfortable. In this sense, architectural choices have the ability to provide experiences, whether physical, functional or psychological, capable of influencing the thermal perception of their occupants. In turn, users of individual rooms play a fundamental role in adjusting the systems that aim to establish thermal comfort conditions of their rooms. Thus, the objective of the study was to verify, through an exploratory analysis, how the use of bioclimatic strategies to obtain environmental comfort by individual office users is able to influence the thermal sensation. For this, a case study was conducted with the teachers and their individual office rooms of the four department buildings at School of Architecture, Arts and Communication of São Paulo State University (UNESP), campus Bauru: Design; Architecture, Urbanism and Landscaping; Humanities; and Arts and Graphic Representation. The research adopted a mixed method with quantitative and qualitative evaluations through, respectively, computer simulation and questionnaires application. The results showed that users of individual offices can have their perception and thermal comfort influenced by non-thermal variables and that the ps... (Complete abstract click electronic access below) / Mestre

The study aimed to assess whether a short-term, high-intensity cold acclimation protocol would modulate finger vasomotor [i.e., finger temperature (TF), cold induced vasodilation (CIVD)] responses and regional thermo-perception to localized cooling. Six men performed a hand cold provocation (consisting of a 30-min immersion in 8°C water), while being whole-body immersed, once, in 21°C water (i.e., cold trial; HYPO), and, the following day, in 35.5°C water (i.e., normothermic trial; NORM). The local cold provocations were repeated, in the same order, after 10 days. In the intervening period, the subjects undertook a whole-body cold acclimation pro-tocol, consisting of daily whole-body 14°C-water immersions for 5 consecutive days, for a maximum of 2 h, while the skin temperature of the right hand was maintained at 35.6 (0.1)°C. Thermal (rectal temperature, skin temperature, finger temperature) cardiorespiratory (mean arterial pressure (MAP), heart rate and oxygen uptake), and perceptual responses (thermal sensation and comfort, pain, affective valence) were monitored throughout the trials. The acclimation protocol resulted in hypothermic adaptation (i.e., habituation), which was characterized by a modest reduction in shivering and an attenuation of whole-body thermal discomfort. The main finding of the study was that, regardless of subjects’ thermal status, the 5-day whole-body cold acclimation protocol did not alter TF (P > 0.1) and CIVD responses (P > 0.2) during local cold stress. Yet, after the acclimation, the cold-induced increase in MAP was reduced and tended to be reduced during the HYPO (P = 0.05) and NORM (P = 0.14) local cold provocation trials, respectively. Furthermore, the perceived thermal discomfort and pain in the immersed hand appeared to be alleviated in all post-acclimation trials.

abstract: The rapid rate of urbanization coupled with continued population growth and anthropogenic activities has resulted in a myriad of urban climate related impacts across different cities around the world. Hot-arid cities are more vulnerable to induced urban heat effects due to the intense solar radiation during most of the year, leading to increased ambient air temperature and outdoor/indoor discomfort in Phoenix, Arizona. With the fast growth of the capital city of Arizona, the automobile-dependent planning of the city contributed negatively to the outdoor thermal comfort and to the people's daily social lives. One of the biggest challenges for hot-arid cities is to mitigate against the induced urban heat increase and improve the outdoor thermal. The objective of this study is to propose a pragmatic and useful framework that would improve the outdoor thermal comfort, by being able to evaluate and select minimally invasive urban heat mitigation strategies that could be applied to the existing urban settings in the hot-arid area of Phoenix. The study started with an evaluation of existing microclimate conditions by means of multiple field observations cross a North-South oriented urban block of buildings within Arizona State University’s Downtown campus in Phoenix. The collected data was evaluated and analyzed for a better understanding of the different local climates within the study area, then used to evaluate and partially validate a computational fluid dynamics model, ENVI-Met. Furthermore, three mitigation strategies were analyzed to the Urban Canopy Layer (UCL) level, an increase in the fraction of permeable materials in the ground surface, adding different configurations of high/low Leaf Area Density (LAD) trees, and replacing the trees configurations with fabric shading. All the strategies were compared and analyzed to determine the most impactful and effective mitigation strategies. The evaluated strategies have shown a substantial cooling effect from the High LAD trees scenarios. Also, the fabric shading strategies have shown a higher cooling effect than the Low LAD trees. Integrating the trees scenarios with the fabric shading had close cooling effect results in the High LAD trees scenarios. Finally, how to integrate these successful strategies into practical situations was addressed. / Dissertation/Thesis / Masters Thesis Architecture 2020