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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
221

Studying building behaviors by using the Building Management System of a new teaching building : A study case of a school building in Stockholm

Zhang, Kaiying January 2020 (has links)
Building management system (BMS) offers a wide range of measurements and historical data about the building but few types of researches use these data to analyze the building performance. This study aims to explore the indoor climate and building insulation by taking advantage of the BMS of the study case, which 767 sensors are installed in the room and wall structures and the signal data are available at the online web application. In addition, during the inspection, several error sensors and meters are detected are discussed as feedback for the system. It is concluded that the building management system is a good tool to study the building performance in different aspects and the measurements from the sensors are helpful but need validation by conducting a further field measurement in the building.
222

Improving indoor thermal comfort in residential buildings in Andean regions of Peru

Basmaci, Benjamin January 2018 (has links)
In the Peruvian Andes, inadequate housing represents an important problem for the local rural people. Over 3000 meters above sea level, communities suffer from very low indoor temperatures this becomes an issue which affects the health and indoor thermal comfort of the building. At early winter mornings, outdoor temperatures can occasionally go down to -15°C and indoor temperatures can drop below zero. Previous work in the field has been done by the Pontifical Catholic University of Peru PUCP, to address thermal comfort in Langui, Peru involving participatory design techniques, multidisciplinary approaches and a focus on sustainability. Their most recent design is based on an attached passive solar heating system similar to a Trombe wall. The effect of housing environment on human health has been an acknowledged issue for many years. In the area, the occupants live with high levels of air infiltration, dirt floor (soil), simple windows, metallic or wood doors, roof most commonly made of corrugated metal sheets, adobe walls, no additional insulation attached and no house heating system. This thesis aims to contribute to a current body of research on thermal comfort and provide insights on how the building environment in Langui can be improved. The main objective is to improve thermal comfort in residential buildings in Andean regions of Peru. An improvement was made by installing a Heat Transfer Rocket which increased the temperature while the relative-humidity stayed steady. Overall, the study shows that indoor improvements can increase thermal comfort in Andean regions of Peru.
223

Improving the thermal climate of schools in semi-desert climate : A case study of solutions in La Guajira, Colombia / Förbättringar av det termiska klimatet på skolor i halvökenklimat : En fallstudie av lösningar i La Guajira, Colombia

Johansson, Michael January 2023 (has links)
As the climate changes, hot regions like La Guajira's semi-desert will become even hotter. It is projected that the average temperature in this region will increase by 2.4 ℃ over the course of this century, with a 20 % reduction in precipitation. To ensure that these areas remain habitable in the future, implementing technical solutions will be necessary to mitigate the impacts on the people living there. A field study assessed the thermal comfort at a school in Manaure, which experiences excessively high temperatures that exceed international standards for good thermal comfort. Through subjective and objective data collection, the field study concluded that the school's thermal climate would negatively impact at least 83 % of the students. The study also found that the surface temperature of desks not exposed to sunlight reached a temperature of 43 ℃. To improve thermal comfort, three potential solutions were explored. Isolating the roof reduces incoming radiation and prevents excess heat from warming the structure. Increasing the ventilation rate helps dissipate hot air, and planting trees creates a cooler supply air temperature. Two of the three measures were implemented, and the tree-planting project is ongoing. Temperatures were measured on the roof, walls, desk and floor during a hot day. Together with a survey to students and teachers to evaluate the absolute temperature and the experienced thermal comfort. The results demonstrated that isolating the roof and installing a solar chimney on the classroom's roof can significantly lower the operative temperature to 36 ℃ and 35 ℃, respectively. These improvements can improve learning by 25 % due to better thermal comfort compared to a classroom that has not been modified. As a bonus, the acoustics were also improved in classrooms, resulting in a lower echo level. Overall, the study demonstrated that it is possible to significantly improve the thermal comfort of classrooms in semi-desert regions, even those without access to electricity. An added benefit is that these solutions have a low installation cost and no operational costs. However, further research is needed to determine the impact of heat on children and whether these measures will improve their learning outcomes. / A medida que cambie el clima, las regiones cálidas como el subdesierto de La Guajira se volverán aún más calientes. Se proyecta que la temperatura promedio en esta región aumente 2,4 ℃ en el transcurso de este siglo, con una reducción del 20 % en las precipitaciones. Para garantizar que estas áreas sigan siendo habitables en el futuro, será necesario implementar soluciones técnicas para mitigar los impactos en las personas que viven allí. Un estudio de campo evaluó el confort térmico en una escuela de Manaure, que experimenta temperaturas excesivamente altas que superan los estándares internacionales de buen confort térmico. A través de la recolección de datos subjetivos y objetivos, el estudio de campo concluyó que el clima térmico de la escuela impactaría negativamente al menos al 83 % de los estudiantes. El estudio también encontró que la temperatura de la superficie de los escritorios no expuestos a la luz solar alcanzó una temperatura de 43 ℃. Para mejorar el confort térmico, se exploraron tres posibles soluciones. Aislar el techo reduce la radiación entrante y evita que el exceso de calor caliente la estructura. El aumento de la tasa de ventilación ayuda a disipar el aire caliente y la plantación de árboles crea una temperatura del aire de suministro más fría. Se implementaron dos de las tres medidas y el proyecto de plantación de árboles está en curso. Se midieron las temperaturas en el techo, las paredes, el escritorio y el piso durante un día caluroso. Junto con una encuesta a estudiantes y docentes para evaluar la temperatura absoluta y el confort térmico experimentado. Los resultados demostraron que aislar el techo e instalar una chimenea solar en el techo del aula puede reducir significativamente la temperatura operativa a 36 ℃ y 35 ℃, respectivamente. Estas mejoras pueden mejorar el aprendizaje en un 25 % debido a un mejor confort térmico en comparación con un aula que no ha sido modificada. Como beneficio adicional, también se mejoró la acústica en las aulas, lo que resultó en un nivel de eco más bajo. En general, el estudio demostró que es posible mejorar significativamente el confort térmico de las aulas en las regiones semidesérticas, incluso aquellas sin acceso a la electricidad. Un beneficio adicional es que estas soluciones tienen un bajo costo de instalación y no tienen costos operativos. Sin embargo, se necesita más investigación para determinar el impacto del calor en los niños y si estas medidas mejorarán sus resultados de aprendizaje. / När klimatet förändras kommer redan varma regioner som halvöken i La Guajira, Colombia att bli ännu varmare. Den genomsnittliga temperaturen i regionen förväntas att öka med 2,4 ℃ under det här århundradet, samtidigt som nederbörden minskar med     20 %. För att dessa områden ska vara beboeliga i framtiden kommer det vara nödvändigt att implementera tekniska lösningar för att mildra konsekvenserna för de människor som bor där. En fältstudie genomfördes för att undersöka termisk komfort på en skola i Manaure, som upplever extremt höga temperaturer vilket överskrider internationella standarder inom termisk komfort. Genom subjektiv och objektiv datainsamling konstaterade fältstudien att skolans termiska klimat kommer påverka minst 83% av eleverna negativt. Studien visade också att temperaturen på skrivborden som inte utsatts för solljus nådde 43 ℃. Temperaturer mättes på tak, väggar, skrivbord och golv under en varm dag. Tillsammans med en undersökning till elever och lärare för att utvärdera den absoluta temperaturen och den upplevda termiska komforten. För att förbättra den termiska komforten undersöktes tre olika möjligheter. Att isolera taket minskar den inkommande strålningen och förhindrar att överflödig värme värmer upp konstruktionen. Ökningen av ventilationen hjälper till att avlägsna het luft och sist även plantera träd för att skapa en svalare utomhustemperatur. Av de tre åtgärderna genomfördes två, och projektet med att plantera träd pågår. Resultaten visade att den operativa temperaturen kan sänkas till 36 ℃ om taket isoleras och ytterligare till 35 ℃ om en solskorsten installeras på taket i klassrummen. Sammantaget kan inlärningen förbättras med åtminstone 25 % jämfört med ett klassrum som inte förbättrades. En positiv bieffekt var att akustiken i klassrummen förbättrades genom mindre eko. Sammanfattningsvis visade studien att det är möjligt att betydligt förbättra den termiska komforten i klassrum i halvökenklimat, även i klassrum utan tillgång till el. En annan fördel är att dessa lösningar har en låg installationskostnad och inga driftskostnader. Dock krävs ytterligare undersökningar för att fastställa vilken påverkan värme har på barn och om dessa åtgärder kommer att förbättra deras lärande.
224

Adaptable housing during crisis : Sustainable transition from tents to permanent accommodations. / Anpassningsbara boenden under kris : en hållbar övergång från tält till permanent boenden.

Dam, Alex January 2023 (has links)
This study delves into the development of a long-term, sustainable housing solution to address the challenges faced during crisis when people are in immediate need of an accommodation. While temporary tents have been traditionally employed as shelters, their inefficiency in colder climates and lack of sustainability necessitate the exploration of alternative options. The proposed solution focuses on the construction of permanent houses equipped with proper insulated floorings, walls, and roofs.  Several crucial factors are taken into consideration throughout this study, including resistance to biological decomposition, exposure to precipitation, breathability, U-value per thickness, storage capabilities, and environmental impact. Therefore, studies and simulations are conducted to evaluate the viability of two organic insulation materials, with the objective of identifying the most suitable option for the project. In the next step energy simulations are conducted using the VIP software, enabling an accurate assessment of the concept building's energy efficiency. Moreover, a detailed model of the housing prototype is constructed using Revit and rendered using Twinmotion, facilitating a comprehensive visualization of the final design. Additionally, the transportation of the developed housing units was investigated and an efficient storage concept for standard shipping container was developed and modelled in SketchUp. With this study a sustainable, lightweight, flexible, adaptable, and easily transportable housing solution that can be constructed without reliance on external forces is to develop. By emphasizing sustainability and resilience, this study provides dignified and long-lasting housing for individuals and communities in need, effectively bridging the gap between temporary shelters and permanent housing structures. The findings and insights obtained from this study contribute to the broader body of knowledge in the field, fostering future advancements in crisis housing and promoting sustainable development practices.
225

Thermal comfort conditions and perception by staff and patients in a Swedish health care center : A measurement and survey field study for summer conditions

Hasan, Md Mahmudul January 2020 (has links)
A challenging aspect of modern global development is to provide desired thermal environment for building occupants with optimum consideration of energy and occupants health and satisfaction, both physically and psychologically. The variation of activity level, health condition, needs, clothing habit and staying time of different categories of occupants in hospitals makes it critical where comfort level should be optimized. Now-a-days, tremendous changing on climate makes even more challenging to maintain optimum level of indoor thermal environment at low energy cost. Thermal comfort can be assessed by the well-established PMV- PPD model, and studies on the correlation with AMV ratings from the occupants can help to understand the exact scenario of the thermal comfort. Therefore, this research aims to estimate the thermal comfort level of healthcare occupants, compare PMV-PPD values with AMV for different categories of occupants, and analyze optimum operative temperature for energy savings. A combination of objective measurements and a field study with a semi-structured interview on comfort perception, following ISO-7726, 7730, 8996, 9920, 10551 and ASHARE- 55 regulations, were conducted, where a total number of 56 occupants, including 35 patients, 5 visitors and 16 medical staffs were participated from a health care center of a hospital in Stockholm, Sweden. The data was collected during the summertime. Based on studied thermal environment, both PMV (-1.59 to 1.01) and AMV range (-2 to 1) considering gender, indicated health care center of studied hospital toward slightly cold, where occupants wanted warmer indoor environment. Patients more than 60 years were most sensitive on thermal comfort and overall patients were more sensitive for warm indoor climate than medical staff due to health condition and age. But male respondents were less sensitive than female. PMV and AMV with optimum operative temperature provides the clear idea about optimum thermal environment for the hospitals occupant. Identifying an optimum thermal environment could be a sustainable solution if and only if energy can be reduced.
226

Thermal Delight in Santo Domingo

Sabater Musa, Luis E. 10 October 2017 (has links)
No description available.
227

Heat Flux Measurements from a Human Forearm under Natural Convection and Isothermal Jets

Ajith N P Shenoy, Shyam Krishna Shenoy 24 August 2017 (has links)
This work is an experimental study on heat transfer from a human arm and a model cylinder. Heat transfer from a human forearm to a large jet, representative of a building HVAC vent/outlet was studied using both an IR camera and a heat flux sensor. The isothermal jet was discharged horizontally from a wind tunnel, at the same temperature as the ambient air. The model cylinder was used to validate the heat transfer results with results from previous studies, using both the IR camera and heat flux sensors. Further, a study on heat transfer to impingement jets from a human forearm at various Reynolds numbers (Re = 9500-41000) and impinging distances of four and eight jet diameters was done. Heat transfer from a human arm to such impingement jets were then compared with heat transfer due to natural convection under both open and controlled environments. A significant increase in convection heat transfer with Reynolds number and distance from the jet outlet was observed. A nearly four-fold increase in convection heat transfer coefficient was obtained when a jet with Reynolds number of 9500 was impinged on a human arm when compared to that obtained under natural convection in an open environment. Empirical correlations for predicting the stagnation and average Nusselt number from a human arm were also developed with high values of correlation coefficients for future studies. Impingement jets were found to be an effective means to transfer heat from human bodies and could potentially be used for creating thermally conditioned microenvironments. / M. S.
228

A Variation of Positioning Phase Change Materials (PCMs) Within Building Enclosures and Their Utilization Toward Thermal Performance

Abuzaid, Abdullah Ibrahim 26 April 2018 (has links)
Recently, buildings have been receiving more serious attention to help reduce global energy consumption. At the same time, thermal comfort has become an increasing concern for building occupants. Phase Change Materials (PCMs), which are capable of storing and releasing significant amounts of energy by melting and solidifying at a given temperature, are perceived as a promising opportunity for improving the thermal performance of buildings. This is because they use their thermophysical properties and latent heat while transforming state (or phase) as a feature for thermal energy storage systems to reduce overall energy demand, specifically during peaks hours, as well as to improve thermal comfort in buildings. This research aims to provide an overview of opportunities and challenges for the utilization of PCMs in the Architecture, Engineering, and Construction (AEC) sector, a broader understanding of specifically promising technologies, and a clarification of the effectiveness of different applications in building enclosures design especially in exterior walls. The research discusses how PCMs can be incorporated within building enclosures effectively to enhance building performance and improve thermal comfort while reducing heating and cooling energy consumption in buildings. The major objectives of the research include studying the properties of PCMs and their potential impact on building construction, clarifying PCMs selection criteria for building application, identifying the effectiveness of utilizing PCMs on saving energy, and evaluating the contribution of utilizing PCMs in building enclosures to thermal comfort. The research uses an exploratory quantitative approach that contains three main stages: 1) a systematic literature review, 2) laboratory experiments, and 3) validation to meet the goal of the research. Finally, by extrapolating results, the research ends with a practical assessment of application opportunities and how to effectively utilize PCMs in exterior walls of buildings. / PHD
229

Physiological and perceptual assessment of thermal comfort and heat strain in garment wear tests using sleeves: an alternative to full-garment tests of chemical protective clothing

Tultrairat, Angkhana 29 August 2008 (has links)
This study was conducted to explore the feasibility of using sleeves, along with both physiological and perceptual measurements, to assess the thermal comfort and heat strain in chemical protective clothing wear tests. The effect of body sites, i.e. the arms and the chest, and the effect of a Tyvek® coverall on skin temperature and sweat amount were investigated as well. Ten male subjects were selected from college students. Each subject was assigned to wear a garment of either T-shirt and pants or a changeable left-sleeved Tyvek® coverall with or without an experimental sleeve on the left arm. Three experimental sleeves were of the same style, but made of three different fabrics: Tyvek®, Pro/Shield I®, and Pro/Shield II®. Each subject wore an assigned garment and pedaled on a cycle ergometer in an environmentally-controlled room. Skin temperature, sweat amount, and subjective comfort evaluations were recorded and later analyzed by repeated-measures ANOVA. Results showed there is a feasibility in using a sleeve with a T-shirt/pants standard garment for assessing thermal comfort in chemical protective garment wear tests. The T-shirt/pants standard garment yielded more consistent and reliable results than did the Tyvek®-coverall standard garment. Under the same conditions, there were no significant differences in skin temperature and sweat amount among the left and right upper arms and the chest. The Tyvek® sleeve in this study impeded the transfer of heat by the greatest amount, followed by the Pro/Shield II® sleeve and the Pro/Shield I® sleeve, respectively. / Master of Science
230

The Environmental Bubble : a study about thermal comfort in residential housing

Mohammad, Mohammad January 2024 (has links)
This thesis explores the concept of thermal comfort in residential architecture, emphasizing a climatic approach that balances the physical needs of the human body with subjective well-being. It investigates the integration of air and heat as building materials in Swedish residential architecture. The study critiques traditional energy-intensive heating and cooling methods, proposing a design ethos that aligns with principles of sustainability and the adaptive thermal comfort model. Through a thermodynamic lens, the thesis follows the paradigm shift in architectural practice, emphasizing performance over form and the unseen meteorological influences within the built environment

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