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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.
1

Experimental assessment and thermal characterisation of lightweight co-polymer building envelope materials

Dimitriadou, Eleni Anastasia January 2015 (has links)
Co-polymer facade materials have recently become a popular option in the building industry as an alternative to glazing. Ethylene Tetra-Fluoro-Ethylene (ETFE) foil has been successfully used in many projects as an innovative solution to energy-conscious design challenges. In addition, the use of ETFE membrane has resulted in significant savings in cost and structural support requirements, compared with conventional glazing, due to its low weight. There is a lack of detailed published data reporting its thermal behaviour. This study focuses on the examination of heat transfer through the ETFE membrane, and more specifically heat loss and solar gains. The document examines the impact of the material on the energy use of a building, as well as thermal comfort and interior conditions. Through field-testing and computer simulations the research evaluates the material’s thermal properties to obtain results that will assist in estimating the suitability of ETFE foil use in comparison to glass. Field-testing is used to perform a comparison of the thermal and energy behaviour of a fritted double ETFE cushion to a double glazed cover. The two experimental devices under examination present nearly identical energy consumption due to heating requirements. The experimental findings are implemented in Integrated Environmental Solutions (IES) and used to identify the necessary steps to accurately reproduce the thermal and energy behaviour associated with both covering materials. Further simulations were undertaken to provide a comparison of several types of ETFE cushions to various types of double glass. More specifically, the types examined are a clear double ETFE roof cover and a fritted double ETFE roof cover in comparison to a standard double glazed roof and a low-E double glazed roof. The roofs covers are examined in relation to energy requirements for both the heating and cooling of a space. Such an assessment of performance will provide information for further investigation to improve the material’s features and optimise energy performance.
2

Design and Construction of a Guarded Hot Box Facility for Evaluating the Thermal Performance of Building Wall Materials

Mero, Claire Renee 2012 May 1900 (has links)
The focus of this study was to design and build a guarded hot box to test the R-Value of building materials. The Riverside Energy Efficiency Laboratory is looking to expand their testing capabilities by including this service. Eventually, the laboratory will become energy star certified. A guarded hot box facility consists of two boxes maintained at specific temperatures and a guard box around each one that is maintained at the same temperature as the box it surrounds. The ASTM C1363 standard was used as guide for the construction and testing of sample specimen. This standard called for an air velocity profile uniform within 10 percent of the average. Velocity tests were performed with various different configurations to give a uniform velocity. Although the velocity did not meet standards, the configuration chosen included a piece of 1/4" pegboard placed 2" away from the top and the bottom of the inner box. By using the known overall heat added and removed from the system, as well as all the heat losses the heat transferred through the specimen and its R-Value can be calculated. The uncertainty of the R-Value and the accuracy of the testing facility gave conflicting results. Future experiments will use improved testing methods that include differential thermocouples to obtain better uncertainty for the R-Value calculations.
3

Optimalizace vlastností formovací směsi vodního jádra hlav válců / Optimalization of properties of moulding sands in water core of cylinder heads

Hlavsa, Petr January 2008 (has links)
Submitted thesis deals with the change of existing binding system for the Hot–Box method for hardening serving for manufacturing of shell cores the water space of cylinder heads comprise of. Objectives for proposing new binding system for Warm–Box method of hardening under heat are to achieve reduction in creation of condensates and gas substances in binding material compared with existing binding system. Further the thesis is aimed at achieving optimal operating hardness the cores have by reduced batches of binding system and by reduced temperatures of cores in scope reflecting manufacturing conditions in the company Nemak Slovakia s.r.o. While resolving issues there were used methods for evaluating quality of opening materials, core mixtures and cores, further methods for evaluating quality of melt, casts and basic methods for statistical processing of results.
4

Heat transfer evaluation of a window with a ”hot box” set-up in a 18th century stone building by using COMSOL software

Erezkano Garai, Garazi January 2019 (has links)
The hot box technique is an experimental method to achieve the U-value of elements in stationary conditions; however, it is not always possible to work in stationary conditions in real world. This thesis consisted of evaluating the heat transfer of a window of a historical building with a unique hot box set-up. The window had a low emissivity plastic film to improve thermal efficiency, and the hot box was unique because the outside temperature could not be controlled. The applicability of the hot box technique to dynamic conditions was assessed using COMSOL Multiphysics 5.3. COMSOL Multiphysics is a finite element method solver software with a heat transfer module. Two heat transfer simulations were conducted in 2D based on the indoor and outdoor temperature when the hot box was in operation. First, a stationary study was carried when the outdoor temperature remained stable for 1 day. Then, the study was extended to a transient study to analyze in detail the effect of the external temperature fluctuations for 5 days. The results indicate that a cautious approach should be taken when applying the hot box technique under transient conditions, but that stationary conditions could not be achieved during one day. Nevertheless, the reliability of the simulation solution could have improved more.
5

Studies into Thermal Transmittance of Conventional and Alternative Building Materials and Associated with Building Thermal Performance

Balaji, N C January 2016 (has links) (PDF)
The present investigation is focused on the thermal performance of building materials, specifically their thermal transmittance, and consequent impact on building envelope and building thermal performance. Thermal performance of building materials plays a crucial role in regulating indoor thermal comfort when suitably integrated as part of the building envelope. Studies into thermal performance of building materials are few, particularly in the context of designing building blocks to achieve a particular thermal transmittance in buildings. Such studies require both theoretical (numerical) investigations augmented with experimental investigation into material thermal performance. A unique contribution of this study has been assessing the temperature-dependent performance of building material and their influence on thermal conductivity. The thermal performance of conventional and alternative (low energy) building materials have also been investigated to assess their suitability for naturally ventilated building in salient climatic zones in India. The study has also investigated the impact of varying mix proportions in Cement Stabilized Soil Block on thermal performance. There is little evidence of such studies, involving both experimental and theoretical studies, tracing the thermal performance of building materials to building performance. The current study involves three parts: studying thermo-physical properties of building materials, building-envelope performance evaluation and case-study investigation on buildings in various climatic zones. The thermo-physical study involves understanding the role of materials mix-proportion, composition, and microstructure for its influence on building-envelope thermal performance. Studies into building envelope performance for conventional and alternative building materials, includes, steady and dynamic thermal performance parameters. As part of the study, a calibrated hot-box thermal testing facility has been tested to experimentally determine the thermal performance of building envelopes. Case-study investigation involves real-time monitoring and simulation based assessment of naturally ventilated buildings in three climatic zones of India. The study finds noticeable temperature-dependent performance for various building materials tested. However, their impact on overall thermal performance of buildings is limited for the climatic zones tested. Further, the study validates the hitherto unexplored possibility of customizing building materials for specific thermal performances.
6

Studium užitných vlastností termoreflexních izolací pro stavebnictví / Study of utility properties thermal-reflective insulations in the buildings

Holeček, Dominik January 2019 (has links)
The diploma thesis is partly dedicated to energetic efficiency of buildings and describes possibilities how to evaluate energetic efficiency of buildings in the Czech Republic. We also get to know with distribution of thermal insulators by material base and use in construction. There are also mentioned methods how to determine thermal insulations characteristics of heat insulations, so called heat conductivity coefficient. The last and the crucial chapter of theoretic part is dedicated to thermal-reflective insulations. There are mentioned some of the basic characteristics of insulations, material composition and heat transfer mechanism in their structure as well. Practical part describes measurement of thermal resistance of chosen samples of thermal-reflective insulations per measuring device on the principal of Hot Box method. In the next step was determined emissivity of aluminium foils which forms the surface of chosen samples of thermal-reflective insulations. In the end of thesis are defined possibilities of use thermal-reflective insulations in building structures especially in passive and low-energy buildings in climatic conditions of the Czech Republic.
7

Studium užitných vlastností tepelně-reflexních izolací pro stavebnictví / Study utility properties of heat-reflective insulation for the buildings

Rauchfussová, Karolína January 2017 (has links)
Presented work deals with the study progressive heat-reflecting foil thermal insulating materials and defines their thermal insulation properties. The work describes a transport mechanism of thermal energy in the structure of heat-reflecting materials, their physical properties, especially heat resistance, compared to the conventional thermal insulating materials available on Czech market. The main applications ways and installation methods of these materials (especially in low-energy and passive buildings) are also shown. The practical part is focused on asembling the measuring device HOT BOX in accordance with the valid standards, to determine the heat resistance of heat-reflecting materials. In next step the measurement of reflection of aluminum foils (an integral part of the structural arrangement heat-reflecting foil insulations) was performed.

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