Academic literature on the topic 'Buildings – Thermal properties – Case studies'
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Journal articles on the topic "Buildings – Thermal properties – Case studies"
1
Laban, Mirjana, and Radomir Folic. "Energy efficiency of industrially made buildings influenced by thermal properties of façades." Thermal Science 18, no. 2 (2014): 615–30. http://dx.doi.org/10.2298/tsci120417147l.
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The main objective of this paper is to evaluate the thermal properties of existing residential buildings built in industrial manner in Novi Sad from 1960 to 1990 based on building typology. Each of three analyzed building type has its characteristic fa?ade, with thermal performances divided into periods according to the development of domestic thermal protection building codes. The necessary layer of subsequent insulation is determined by calculations in order to comply with European standards, also applied in Serbia from 2012. The proposed method of periodization simplifies the process of thermal performance assessment and it was checked through the case studies. Evaluation of energy consumption rationalization has been done through comparative analysis of energy losses. Based on the most common energy rehabilitation measures applied in Serbia, it was estimated that it was possible to reduce the energy losses in heating up to 60%.
2
Ba, Labouda, Ikram El Abbassi, Cheikh S. E. Kane, A.-M. Darcherif, and Mamoudou Ndongo. "Thermal performance of biosourced materials on Buildings: The case of Typha Australis." MATEC Web of Conferences 330 (2020): 01011. http://dx.doi.org/10.1051/matecconf/202033001011.
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Developing countries are facing population growth, which leads, on the one hand, to increased requirements for buildings and, on the other hand, to the depletion of fossil fuels along with exposure, of people living in those areas, to some detrimental consequences of climate change. Because of these factors, we propose approaches to control energy consumption in buildings. In some countries, the architectures adopted are not adequate to the environment and climate, resulting in discomfort in those buildings, in such circumstances, residents resort to the use of energy systems, such as heating, ventilation, and air conditioning, which leads to exorbitant electricity bills. Housing consumes 40% of the world's energy and is responsible for a third of greenhouse gas emissions. Optimizing energy needs in buildings is a solution to overcome these problems. For this purpose, there are solutions such as: the design of the building characterized by its shape and envelope, while using less energy-consuming equipment. For several years, the building materials sector has been developing with a particular focus on bio-source materials, which are generally materials with good thermal performance. In order to highlight the thermal performance of bio-source materials, we will study the case of Typha Australis which is a plant of the Typhaceae family that grows abundantly in an aquatic environment mainly in the Senegal River valley.Recent studies showed that Typha Australis has good thermal insulation properties. In order to determine the impact of Typha Australis on a building, a dynamic thermal simulation was carried out using the Trnsys software according to specific scenarios, the Typha was mixed with other local materials and used as a wall insulation panel, the result of the study shows that this fiber has allowed us to optimize energy consumption in a building. Mixing Typha with other materials (e. g. clay) is a promising solution for energy efficiency in buildings.
3
Zahiri, Sahar, and Hasim Altan. "Improving energy efficiency of school buildings during winter season using passive design strategies." Sustainable Buildings 5 (2020): 1. http://dx.doi.org/10.1051/sbuild/2019005.
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Passive building design can improve energy efficiency of buildings, while providing comfortable indoor environment for occupants with minimum mechanical energy use. The foundation of passive design depends on natural sources of energy, which uses building architecture and surrounding environment to minimise heating and cooling loads of buildings with minimum operating and maintenance costs. The correlation of local climate with shape and thermal performance of buildings is one of the main considerations of passive design approach to reduce energy use and increase thermal comfort of occupants. This paper focuses on a series of field studies and building simulation analysis to improve thermal performance of female secondary school buildings in the city of Tehran in Iran during winter season using passive design strategies. The field studies included measuring indoor air temperature, as well as a questionnaire-based survey in a cold winter season in a typical female secondary school building. The on-site monitoring assessed indoor air temperature of classrooms while the occupants completed questionnaires covering their thermal sensations and thermal preferences. Moreover, building thermal simulation analysis were carried out using DesignBuilder tool to evaluate and improve thermal performance of classrooms based on students' thermal requirements and passive design strategies. The simulation analysis started from the basic school building model, investigating various passive design strategies to predict the optimum design strategies for the case study. The simulation results determined how to provide classrooms that are more comfortable for students with minimum energy use. The results of the field studies indicated that indoor thermal environment were usually comfortable for female students based on 7-point ASHRAE scale. However, most of the occupants preferred their indoor thermal environment to be improved. Moreover, simulation results showed that building fabrics and thermal properties, as well as glazing and orientation had significant impacts on indoor air temperature and thermal comfort and using appropriate passive design strategies could improve energy efficiency of the building considerably. Therefore, in order to enhance indoor thermal environment and to increase learning performance of students, it is necessary to use appropriate low energy methods, which can reduce the needs for mechanical energy systems and hence save energy.
4
Netinger Grubeša, Ivanka, Mihaela Teni, Hrvoje Krstić, and Martina Vračević. "Influence of Freeze/Thaw Cycles on Mechanical and Thermal Properties of Masonry Wall and Masonry Wall Materials." Energies 12, no. 8 (April 17, 2019): 1464. http://dx.doi.org/10.3390/en12081464.
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In this study, the influence of freeze/thaw cycles on the mechanical and thermal properties of bricks and mortar as building parts of masonry walls, as well as the influence on the masonry wall itself is investigated. At the material level, the influence of freeze and thaw cycles on the mechanical and thermal properties of masonry components (bricks and mortar) was investigated; at the construction level, the influence of freeze and thaw cycles on the mechanical and thermal properties of a masonry wall was studied. To study the influence of freezing on the energy demand characteristics of masonry buildings, in terms of energy conservation and greenhouse gas emission, a case study was investigated on a typical structure of a historical building located in Croatia, that had undergone a process of energy certification. The applied freeze/thaw regime negatively influenced the compressive strength and the thermal properties of bricks and mortar, as well as the mechanical and thermal properties of the wall. Considering the thermal properties of the material before and after its exposure to freeze/thaw cycles, we concluded that the annual energy consumption, the heating costs, and the CO2 emission of a family house could increase up to 3.7% after frost action in the studied case.
5
Szkordilisz, Flóra, and Márton Kiss. "Potential of Vegetation in Improving Indoor Thermal Comfort and Natural Ventilation." Applied Mechanics and Materials 824 (January 2016): 278–87. http://dx.doi.org/10.4028/www.scientific.net/amm.824.278.
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According to the EPBD (2010) whilst improving the thermal performance of buildings good or at least tolerable thermal comfort conditions must be provided. But better thermal insulation and more airtight buildings increase the risk of summer overheating which makes mechanical cooling inevitable. This idea has been verified by the tendency of the last decade, when people were willing to install and use more frequently air conditioning devices during the summer heatwaves – increasing their energy consumption and electricity bills at the same time. We cannot neglect the importance of studies triggering an efficient way to minimise the cooling load of residential buildings by obstructing solar radiation. The usage of plants in front of transparent surfaces of the façade can avoid indoor overheating. Deciduous plants obstruct buildings’ solar access so that the microclimate around the building is improved too. The use of Green Infrastructure in different levels of planning processes, which would provide sustainable solutions for urban management, is also prescribed in the EU Biodiversity Strategy 2020. Of course in order to investigate the actual effect of trees on indoor thermal comfort we should take into consideration a list of other factors: such as orientation the type and thermal properties of the windows / transparent structures used, and the thermal transmittance values and heat storage capacity of the building. If we have taken into consideration the mentioned factors during simulation we can prove the effectiveness of vegetation for each case. Simulations are made on the base of transparency measurements carried out during the summer of 2014. The shading efficiency of trees is a species-specific attribute because of the varying crown structure and leaf density. Our analyses aimed at the quantification of the transmissivity of characteristic individuals of three frequently planted species (Celtis occidentalis, Sophora japonica, Tilia cordata). The measured data were the amount of transmitted shortwave radiation, compared with a measurement point under unobstructed sunlight. In preliminary studies we have shown that depending on species – a tree in front of the façade can decrease the solar gain on internal horizontal surface up to ~18-30 per cents. As the tree obstructs the solar access of the wall and that of transparent surfaces, a difference in indoor comfort is to be observed too.
6
Moreno Santamaria, Belen, Fernando del Ama Gonzalo, Danielle Pinette, Roberto-Alonso Gonzalez-Lezcano, Benito Lauret Aguirregabiria, and Juan A. Hernandez Ramos. "Application and Validation of a Dynamic Energy Simulation Tool: A Case Study with Water Flow Glazing Envelope." Energies 13, no. 12 (June 19, 2020): 3203. http://dx.doi.org/10.3390/en13123203.
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The transparent materials used in building envelopes significantly contribute to heating and cooling loads of a building. The use of transparent materials requires to solve issues regarding heat gain, heat loss, and daylight. Water flow glazing (WFG), a disruptive technology, includes glazing as part of the Heating, Ventilation and Air Conditioning (HVAC) system. Water is transparent to visible wavelengths, but it captures most of the infrared solar radiation. As an alternative to fossil fuel-based HVAC systems, the absorbed energy can be transferred to the ground through borehole heat exchangers and dissipated as a means of free-cooling. Researchers of the Polytechnic University of Madrid have developed a software tool to calculate the energy balance while incorporating the dynamic properties of WFG. This article has studied the mathematical model of that tool and validated its ability to predict energy savings in buildings, taking spectral and thermal parameters of glazing catalogs, commercial software, and inputs from the measurements of the prototypes. The results found in this article showed that it is possible to predict the thermal behavior of WFG and the energy savings by comparing the thermal parameters of two prototypes. The energy absorbed by the water depends on the mass flow rate and the inlet and outlet temperatures.
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Giro-Paloma, Jessica, Camila Barreneche, Alex Maldonado-Alameda, Miquel Royo, Joan Formosa, Ana Inés Fernández, and Josep M. Chimenos. "Alkali-Activated Cements for TES Materials in Buildings’ Envelops Formulated With Glass Cullet Recycling Waste and Microencapsulated Phase Change Materials." Materials 12, no. 13 (July 3, 2019): 2144. http://dx.doi.org/10.3390/ma12132144.
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Within the thermal energy storage field, one of the main challenges of this study is the development of new enhanced heat storage materials to be used in the building sector. The purpose of this study is the development of alkali-activated cements (AACs) with mechanical properties to store high amounts of heat. These AACs incorporate wastes from industrial glass process as well as microencapsulated phase change materials (mPCMs) to improve the thermal inertia of building walls, and accordingly respective energy savings. The research presented below consists of the exhaustive characterization of different AACs formulated from some waste generated during the proper management of municipal waste used as precursor. In this case study, AACs were formulated with the waste generated during the recycling of glass cullet, namely ceramic, stone, and porcelain (CSP), which is embedding a mPCM. The addition of mPCM was used as thermal energy storage (TES) material. The mechanical properties were also evaluated in order to test the feasibility of the use of the new formulated materials as a passive TES system. The results showed that the AAC obtained from CSP (precursors) mixed with mPCMs to obtain a thermal regulator material to be implemented in building walls was reached successfully. The material developed was resistant enough to perform as insulating panels. The formulated materials had high storage capacity depending on the PCM content. The durability of the mPCM shell was studied in contact with alkaline medium (NaOH 4 M) and no degradation was confirmed. Moreover, the higher the content of mPCM, the lower the mechanical properties expected, due to the porosity increments with mPCM incorporation in the formulations.
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Ovsyannikov, V. E., G. N. Shpitko, R. Yu Nekrasov, and D. E. Vas'kov. "Increase of strength of cast-iron cylinder liners of engines of road construction vehicles." Izvestia MGTU MAMI 1, no. 3 (2020): 36–40. http://dx.doi.org/10.31992/2074-0530-2020-45-3-36-40.
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Cylinder liners made of gray cast iron are quite widespread in the design of engines of road con-struction vehicles. The negative properties of this structural material include relatively low strength and high fragility. This increases the probability of both manufacturing and operational defects. Therefore, improving the performance of the considered parts is an urgent problem. A promising direction in this case is the use of chemical-and-thermal treatment. The aim of the work is to study the effect of chemical-and-thermal treatment of gray cast iron on strength. The paper investigates the strength of cast iron subjected to chemical-and-thermal treatment (thermal diffusion surface al-loying). On the basis of experimental studies, the effect of the thickness of the hardened layer on the strength was studied. A numerical model is created in the Ansys software. The effect of the hardened layer on the strength of cylinder liners of engines of road-building vehicles is investigated.
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Motaung, Tshwafo E., and Mokgaotsa J. Mochane. "Systematic review on recent studies on sugar cane bagasse and bagasse cellulose polymer composites." Journal of Thermoplastic Composite Materials 31, no. 10 (November 28, 2017): 1416–32. http://dx.doi.org/10.1177/0892705717738292.
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Sugar cane bagasse (SCB) is one of the abundant and available natural fibres in many countries as a by-product from sugar cane mills after an extraction of sugar. Attempts have been made to convert this by-product into useful eco-friendly cement-bonded composites and polymer composites, which can be used for various internal and external applications in buildings. Some researchers extracted cellulose from SCB and incorporated it in different polymeric matrices. The investigations included optimization of parameters and chemical treatments such as bagasse content or coupling agents for a production of effective composites. The influence of different parameters on the setting of the composite material such as botanical components of the fibre, thermal or chemical treatment of the fibre and bagasse fibre content have shown enhancement in properties. The recent work cited in this review suggests that SCB can be used to prepare fibre-reinforced polymer composites for commercial use. Furthermore, there seems to be a little research done on the application of SCB nanocellulose–polymer composites. In fact, this review discusses the current state of SCB as filler in polymer composites with citation of the latest research. It furthermore exposes more research options for SCB and its ash.
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Rosato, Antonio, Antonio Ciervo, Renata Concetta Vigliotti, Roxana Adina Toma, Rossana Pellegrino, Giovanni Ciampi, Michelangelo Scorpio, and Sergio Sibilio. "Influence of Climatic Conditions on Dynamic Performance of Solar Hybrid Heating and Cooling Systems Integrating Seasonal Borehole Thermal Energy Storages: Application to School Buildings in the Campania Region of Italy." Tecnica Italiana-Italian Journal of Engineering Science 65, no. 2-4 (July 30, 2021): 187–95. http://dx.doi.org/10.18280/ti-ijes.652-407.
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In this paper 5 different case studies of solar hybrid heating and cooling networks serving 5 different school buildings assumed as representative of the 5 provinces of the Campania region (southern Italy) have been modelled, dynamically simulated and analyzed by means of the software TRNSYS over a 5-year period. The plants are based on the operation of solar thermal collectors coupled with a seasonal borehole thermal energy storage; the solar field is also integrated with photovoltaic panels coupled with an electric energy storage; a solar-powered adsorption system is used for covering the cooling requirements. Specific weather data files have been developed for each city based on 1-year in-situ hourly measurements to accurately take into account the influence of climatic conditions on systems’ performance; the effects of thermo-physical properties of underground associated to the different locations have also been taken into consideration according to measured data available in the literature. The proposed systems have been compared with conventional Italian heating and cooling plants from energy, environmental and economic points of view in order to assess the potential benefits, highlight the effects of both weather data and characteristics of underground as well as promote the diffusion of solar systems for Italian applications.
Dissertations / Theses on the topic "Buildings – Thermal properties – Case studies"
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Kirmizi, Hacer. "The Effect Of Sun Spaces On Temperature Patterns Within Buildings: Two Case Studies On The Metu Campus." Master's thesis, METU, 2010. http://etd.lib.metu.edu.tr/upload/2/12611427/index.pdf.
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The aim of this study was to investigate the passive and active parameters affecting
energy efficiency of two office buildings with sun spaces, namely the MATPUM
Building and the Solar Building on the Middle East Technical University (METU)
Campus, Ankara and the effect of sun spaces on temperature patterns within
mentioned buildings. Both buildings were oriented in the same direction, namely
south. However, the location and the type of the sunspaces differed from each other.
The sun space in the MATPUM Building is an atrium which has southerly glazed
façade. On the other hand, the sun space in the Solar Building is an enclosed conservatory which has southerly glazed faç
ades and roof. The effect of sun spaces on temperature patterns within case study buildings was determined by collecting internal temperature and humidity data from different locations within the buildings and external temperature and humidity data on certain days of the week from May to August and October and November. Data loggers were used to collect these data. The collected data was then compared for the two buildings and also for the different months. In conclusion, more heat gain resulting in temperature increase inside the buildings was obtained in conservatories when compared to the atria which have glazed faç
ade instead of glazed roof. This was also proved by the analysis of variance method which was used for the comparison of temperature data of two buildings
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Elwefati, Nahla Adel. "Bio-climatic Architecture In Libya: Case Studies From Three Climatic Regions." Master's thesis, METU, 2007. http://etd.lib.metu.edu.tr/upload/12608674/index.pdf.
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The aim of this study was to investigate the bio-climatic characteristics of
traditional and contemporary residential architecture in three different
climatic/geographical regions of Libya, which are represented by Tripoli in the
&ldquocoastal region&rdquo
Gharyan in the &ldquo
mountainous region&rdquo
and Ghadames in the &ldquo
desert region&rdquo
. It was undertaken to understand and evaluate the effects of building layout and orientation, wall thicknesses, ceiling height, construction materials, thermal mass and size of windows, on the resultant thermal comfort conditions of the buildings/dwellings in question. An architectural survey of the dwellings was carried out and indoor and outdoor photos of houses were taken. Temperature and humidity data in pre-determined rooms of the dwellings, in addition to data relevant to exterior weather conditions were recorded by thermo-hygrometers. Residents who had experience of living in both traditional and contemporary dwellings were interviewed informally before preparing a comprehensive questionnaire, which was distributed to them to gather the required data. It was found that traditional dwellings in Tripoli and Ghadames, in their present condition, did not provide the desired level of thermal comfort. This was attributed to a number of reasons. One was the abandonment of these dwellings by their occupants, in favor of those of modern style. The resulting collapse of some parts of adjacent house blocks, which used to provide a degree of protection against climatic conditions when working as a whole block of several attached houses. Another was the introduction of new construction materials that were incompatible with the original ones. However, traditional dwellings in both cities appeared to provide relatively better thermal comfort conditions in comparison with the use contemporary dwellings of recent years, except for those with air conditioning. This situation was different in Gharyan, where the troglodyte dwellings were concerned. These dwellings were thermally more comfortable than the modern ones in the city. This was attributed to the fact that most of the existing troglodyte dwellings still preserved their original features to a large extent. At length, this study recommends that modern types of dwellings should adapt those features of the traditional ones that are more compatible and suitable for the local climatic conditions, in a way which guarantees optimum exploitation of local resources in terms of energy consumption and cost.
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Ko, Hsin-Ting. "Techno-economic analysis of demand flexibility from heat pumps for multi-family buildings in Sweden based on two case studies." Thesis, KTH, Energiteknik, 2020. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-272472.
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Sweden is undergoing energy transition to become a zero-carbon economy with electricity production aims at 100% from renewable resources by 2040. Sweden also has a national goal to have fossil-free vehicle fleet by 2030. The increasing share of intermittent renewable resources creates growth in mismatches between electricity supply and demand. Demand flexibility provides solution to imbalances in power system where the prosumers can regulate their energy consumption. Demand response (DR) mechanism could be beneficial to power gird stability. Electric heat pumps serve as a pool of flexible load meanwhile the thermal inertia of the residential buildings serves as thermal energy storage. In this thesis, a techno-economic analysis of demand flexibility from heat pumps for residential buildings located in central Örebro is carried out with assistance of building energy simulations. This thesis aims to improve the intelligence of this existing buildings by comprehending the size of thermal inertia availability according to different heat demand, building envelope materials, ventilation systems, weather conditions and user behaviors. Two multi-family residential buildings, Klockarängsvägen and Pärllöken, are selected for case study and compared in terms of thermal inertia and avoided peak power fees in avoided peak power fee from flexible heat pump loads. Both buildings use heat pumps for space heating and domestic hot water supply. Electricity billings are subscribed to power tariff scheme, which makes peak power shifting more profitable. On the coldest day scenario when the ambient temperature is -20°C, Pärllöken’s indoor temperature drops from 21°C to 19.1°C if heat pump is turned off for an hour. Klockarängsvägen’s indoor temperature drops from 21°C to 16.6°C if heat pump is turned off for an hour. At the lowest indoor temperature setpoint of 18°C, Pärllöken demonstrates a maximum power-shift capacity of 25 kW and heatshift capacity of 75 kWh on the coldest day. That of Klockarängsvägen is a maximum power-shift capacity of 20 kW and heat-shift capacity of 20 kWh. With larger building thermal inertia and more power-shift capacity, Pärllöken is undoubtedly the winner thanks to concrete wall materials, heavier building thermal mass, balanced ventilation, heat recovery system, and higher window class. In economic analysis, based on the proposed energy models, two control strategy options in Pärllöken are considered. Economic analysis focuses on winter season from October to March. Option 1 operates heat pump in variable capacity control mode at part load capacity. Option 2 operates in fixed capacity on/off -4- control. In winter season, Pärllöken saves 1 646 SEK in Option 1 and 2 273 SEK in Option 2. Klockarängsvägen only considers Option 1 for economic analysis, which results in 20 948 SEK avoided peak power fee. Option 2 for Klockarängsvägen exceeds indoor temperature setpoint very quickly mainly due to poorer building envelope insulation in which conserves lower thermal inertia.Sverige genomgår en energitransformation för att bli en fossilfri ekonomi som siktar på att ha en elproduktion från 100% förnybara resurser år 2040. Sverige har också ett nationellt mål att ha en fossilfri fordonsflotta till 2030. Den ökande andelen av intermittenta förnybara resurser bidrar till ökning av obalans mellan produktion och efterfråga av elektricitet. Efterfrågeflexibilitet ger en lösning på problemet med obalanser i energisystemet där prosumenter kan reglera sin energiförbrukning. Efterfrågeflexibilitet kan vara fördelaktigt för kraft- och nätstabilitet. Elektriska värmepumpar kan agera som en stor flexibel last samtidigt som fastighetens termiska tröghet fungerar som värmeenergilagring. I denna avhandling utförs en teknisk-ekonomisk analys av efterfrågeflexibilitet från värmepumpar för två bostadshus beläget i centrala Örebro med hjälp av energisimuleringar av fastigheten. Genom denna avhandling syftar författaren på att höja intelligensen av de befintliga fastigheterna genom att undersöka storleken av den termiska trögheten som finns tillgänglig med avseende på olika värmescenario, byggnadsmaterial, ventilationssystem, väderförhållanden och användarbeteenden. Två flerfamiljshus, Klockarängsvägen och Pärllöken, väljs för jämförelse med avseende på den termisk tröghet som bidrar mest till efterfrågeflexibiliteten. De två utvalda fastigheterna använder värmepumpar för värme och varmvatten. Båda fastigheterna faktureras enligt effektabonnemang, vilket gör effektutjämning mer lönsamt. I det kallaste scenariot, när omgivningstemperaturen är -20°C, faller Pärllökens inomhustemperatur från 21°C till 19,1°C och Klockarängsvägens inomhustemperatur sjunker till 16,6°C om värmetillförseln stängs av i en timme. Under det lägsta börvärdet för inomhustemperatur på 18°C visar Pärllöken en maximal effektförskjutningskapacitet på 25 kW och för Klockarängsvägen-byggnader 20 kW. Med hänsyn till fastighetens termiska tröghet är Pärllöken utan tvekan vinnaren på grund av betong som väggsmaterial, högre termisk massa, balanserad ventilation, värmeåtervinningssystem och högre energiklass på fönsterglasen. Ovanstående skäl gör att Pärllökens termiska tidskonstant är minst tre gånger längre innan temperaturen når det lägsta börvärdet på 18°C, jämfört med Klockarängsvägen. Detta ger att Pärllöken har en högre förskjutningskapacitet av värme på 75 kWh jämfört med Klockarängsvägens maximala förskjutningskapacitet på 20 kWh. I en ekonomisk analys, baserat på författarens framtagna energimodeller, beaktas två styrstrategier i Pärllöken. Den ekonomiska analysen fokuserar på vintersäsongen från oktober till mars. Alternativ 1 driver värmepumpen med partiell kapacitet enligt reglerbar effekt. Alternativ 2 stänger av värmepumpen helt. Under vintersäsongen sparar Pärllöken 1 646 SEK med Alternativ 1 och 2 273 SEK med Alternativ 2. Klockarängsvägen använder sig endast av Alternativ 1 för en ekonomisk analys, vilket resulterar i en kostnadsbesparing på 20 948 SEK. En förstudie med värmepump i kombination med andra förnybara tekniker så som solceller på Klockarängsvägen genomförs för att undersöka potentialen av energibesparing. Kombinationen ger dock inte en positiv effekt på grund av den låga solinstrålningen under vintertid.
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Boozula, Aravind Reddy. "Use of Bio-Product/Phase Change Material Composites in the Building Envelope for Building Thermal Control and Energy Savings." Thesis, University of North Texas, 2008. https://digital.library.unt.edu/ark:/67531/metadc1248391/.
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This research investigates the bio-products/phase change material (PCM) composites for the building envelope application. Bio-products, such as wood and herb, are porous medium, which can be applied in the building envelope for thermal insulation purpose. PCM is infiltrated into the bio-product (porous medium) to form a composite material. The PCM can absorb/release large amount of latent heat of fusion from/to the building environment during the melting/solidification process. Hence, the PCM-based composite material in the building envelope can efficiently adjust the building interior temperature by utilizing the phase change process, which improves the thermal insulation, and therefore, reduces the load on the HVAC system. Paraffin wax was considered as the PCM in the current studies. The building energy savings were investigated by comparing the composite building envelope material with the conventional material in a unique Zero-Energy (ZØE) Research Lab building at University of North Texas (UNT) through building energy simulation programs (i.e., eQUEST and EnergyPlus). The exact climatic conditions of the local area (Denton, Texas) were used as the input values in the simulations. It was found that the EnergyPlus building simulation program was more suitable for the PCM based building envelope using the latent heat property. Therefore, based on the EnergyPlus simulations, when the conventional structure insulated panel (SIP) in the roof and wall structures were replaced by the herb panel or herb/PCM composite, it was found that around 16.0% of energy savings in heating load and 11.0% in cooling load were obtained by using PCM in the bio-product porous medium.
5
Boozula, Aravind Reddy. "Use of Bio-Product/Phase Change Material Composite in the Building Envelope for Building Thermal Control and Energy Savings." Thesis, University of North Texas, 2018. https://digital.library.unt.edu/ark:/67531/metadc1248391/.
Full textAbstract:
This research investigates the bio-products/phase change material (PCM) composites for the building envelope application. Bio-products, such as wood and herb, are porous medium, which can be applied in the building envelope for thermal insulation purpose. PCM is infiltrated into the bio-product (porous medium) to form a composite material. The PCM can absorb/release large amount of latent heat of fusion from/to the building environment during the melting/solidification process. Hence, the PCM-based composite material in the building envelope can efficiently adjust the building interior temperature by utilizing the phase change process, which improves the thermal insulation, and therefore, reduces the load on the HVAC system. Paraffin wax was considered as the PCM in the current studies. The building energy savings were investigated by comparing the composite building envelope material with the conventional material in a unique Zero-Energy (ZØE) Research Lab building at University of North Texas (UNT) through building energy simulation programs (i.e., eQUEST and EnergyPlus). The exact climatic conditions of the local area (Denton, Texas) were used as the input values in the simulations. It was found that the EnergyPlus building simulation program was more suitable for the PCM based building envelope using the latent heat property. Therefore, based on the EnergyPlus simulations, when the conventional structure insulated panel (SIP) in the roof and wall structures were replaced by the herb panel or herb/PCM composite, it was found that around 16.0% of energy savings in heating load and 11.0% in cooling load were obtained by using PCM in the bio-product porous medium.
6
Qiu, Bin. "Simulating Thermal and Chemical Spills in Coupled Cooling Reservoirs." Thesis, University of North Texas, 1997. https://digital.library.unt.edu/ark:/67531/metadc279271/.
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Hot water discharges and potential chemical spills are factors that threaten water
quality in cooling reservoirs of chemical and power plants. In this thesis, three models are used to analyze the impact of these factors in a particular case study.
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Reas, Pinto Alberto Cruz. "Hygrothermic rehabilitation in the exterior panels of prefabricated buildings by external thermal insulation composite systems (ETICS) with rendering : (two 'case studies', located in the Lisbon metropolitan area - SAC and QM)." Thesis, University of Salford, 2001. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.395737.
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Talele, Suraj Harish. "Comparative Study of Thermal Comfort Models Using Remote-Location Data for Local Sample Campus Building as a Case Study for Scalable Energy Modeling at Urban Level Using Virtual Information Fabric Infrastructure (VIFI)." Thesis, University of North Texas, 2018. https://digital.library.unt.edu/ark:/67531/metadc1404602/.
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The goal of this dissertation is to demonstrate that data from a remotely located building can be utilized for energy modeling of a similar type of building and to demonstrate how to use this remote data without physically moving the data from one server to another using Virtual Information Fabric Infrastructure (VIFI). In order to achieve this goal, firstly an EnergyPlus model was created for Greek Life Center, a campus building located at University of North Texas campus at Denton in Texas, USA. Three thermal comfort models of Fanger model, Pierce two-node model and KSU two-node model were compared in order to find which one of these three models is most accurate to predict occupant thermal comfort. This study shows that Fanger's model is most accurate in predicting thermal comfort. Secondly, an experimental data pertaining to lighting usage and occupancy in a single-occupancy office from Carnegie Mellon University (CMU) has been implemented in order to perform energy analysis of Greek Life Center assuming that occupants in this building's offices behave similarly as occupants in CMU. Thirdly, different data types, data formats and data sources were identified which are required in order to develop a city-scale urban building energy model (CS-UBEM). Two workflows were created, one for an individual scale building energy model and another one for CS-UBEM. A new innovative infrastructure called as Virtual Information Fabric Infrastructure (VIFI) has been introduced in this dissertation. The workflows proposed in this study will demonstrate in the future work that by using VIFI infrastructure to develop building energy models there is a potential of using data for remote servers without actually moving the data. It has been successfully demonstrated in this dissertation that data located at remote location can be used credibly to predict energy consumption of a newly built building. When the remote experimental data of both lighting and occupancy are implemented, 4.57% energy savings was achieved in the Greek Life Center energy model.
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Smith, Carol Elaine. "A method for determining the installed capacity of an underfloor electrical resistance heating and energy storage system." 1985. http://hdl.handle.net/2097/27546.
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"Experimental studies thermally of ecological building in Loess Plateau areas of China." 2006. http://library.cuhk.edu.hk/record=b5896466.
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Mu Jun.Thesis submitted in: December 2005.
Thesis (M.Phil.)--Chinese University of Hong Kong, 2006.
Includes bibliographical references (leaves 181-183).
Abstracts in English and Chinese.
Chapter 1. --- Introduction --- p.1
Chapter 2. --- Issues and Background --- p.5
Chapter 2.1. --- Why Ecological Architecture? --- p.5
Chapter 2.1.1. --- Fossil Fuels and Environmental Issues --- p.5
Chapter 2.1.2. --- The Buildings' Role in the Issues --- p.9
Chapter 2.2. --- Knowledge in Ecological Design --- p.11
Chapter 2.2.1. --- About Ecological Architecture --- p.11
Chapter 2.2.2. --- Thermal Study ~ A Significant Way to Ecological Architecture --- p.13
Chapter 2.2.3. --- What is Suitable Ecological Architecture for Loess Plateau areas of China --- p.16
Chapter 3. --- Defining the Future Ecological Architecture in Loess Plateau Areas --- p.20
Chapter 3.1. --- Economy for Building --- p.20
Chapter 3.1.1. --- Situation --- p.20
Chapter 3.1.2. --- Technological Strategies towards a Cost-effective Ecological Approach --- p.22
Chapter 3.1.3. --- Alternative-Technological Approach --- p.24
Chapter 3.2. --- Climate --- p.25
Chapter 3.2.1. --- Climatic Characteristics --- p.25
Chapter 3.2.2. --- A climatically Responsive Approach ~ Selective Environmental Design --- p.32
Chapter 3.2.3. --- Climatic Response of Thermal Design Guidelines --- p.33
Chapter 3.2.3.1. --- Minimizing Heat loss through Building Fabrics --- p.34
Chapter 3.2.3.2. --- Utilization of Available Natural Energy --- p.37
Chapter 3.3. --- Benefits from Vernacular Architecture --- p.45
Chapter 3.3.1. --- Earth ArchitecturéؤVernacular Architecture on Loess Plateau --- p.45
Chapter 3.3.1.1. --- Classification --- p.46
Chapter 3.3.1.2. --- Environmental Performance --- p.53
Chapter 3.3.2. --- Literature Review of Studies on Earth Architecture --- p.58
Chapter 3.3.2.1. --- Properties of Earth-based Materials --- p.58
Chapter 3.3.2.2. --- Literature on Earth Architecture --- p.60
Chapter 3.3.3. --- Issues and Development --- p.76
Chapter 3.3.3.1. --- Limitation in Existing Earth Architecture of Loess Plateau --- p.76
Chapter 3.3.3.2. --- Recent Research on Developing Earth Architecture in Loess Plateau Areas --- p.77
Chapter 3.3.3.3. --- Considerations --- p.81
Chapter 3.4. --- Conclusion --- p.82
Chapter 4. --- Making of the Classroom as Designed for the Thermal Study --- p.84
Chapter 4.1. --- Why a Classroom? --- p.84
Chapter 4.2. --- The School Project and the Classroom Simulated --- p.85
Chapter 5. --- Thermal Study by Simulating Experiments --- p.88
Chapter 5.1. --- Research Methodology --- p.88
Chapter 5.2. --- Program Validation --- p.89
Chapter 5.3. --- Experimental Series of Simulation and Model Setup --- p.93
Chapter 5.4. --- Thermal Mass and Insulation --- p.95
Chapter 5.4.1. --- External Wall --- p.95
Chapter 5.4.2. --- Roof Study --- p.97
Chapter 5.4.3. --- "Windows, Doors and Glazing" --- p.100
Chapter 5.4.4. --- Incorporated Performance --- p.103
Chapter 5.5. --- Passive system for natural energy use --- p.106
Chapter 5.5.1. --- Passive Solar System Study --- p.106
Chapter 5.5.1.1. --- Wall-based Passive Solar System --- p.106
Chapter 5.5.1.2. --- Roof-based Passive Solar System --- p.125
Chapter 5.5.1.3. --- System Comparison in Thermal Performance --- p.135
Chapter 5.5.2. --- Natural Ventilation System with the Heat Exchanger --- p.137
Chapter 5.5.2.1. --- Pre-warming Effect of the Solar Space --- p.139
Chapter 5.5.2.2. --- Effect of the Earth-air-tunnel --- p.142
Chapter 5.5.2.3. --- Incorporation with the Chimney --- p.153
Chapter 5.5.2.4. --- Comparison in Performance --- p.158
Chapter 5.6. --- Summary --- p.159
Chapter 6. --- Design Improvement and Performance Prediction --- p.162
Chapter 6.1. --- System Incorporation and Design Improvement --- p.161
Chapter 6.2. --- Thermal Performance Prediction --- p.167
Chapter 7. --- Conclusion --- p.174
Appendix --- p.179
Books on the topic "Buildings – Thermal properties – Case studies"
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Developing Hospitality Properties & Facilities. San Diego: Elsevier Science & Technology, 2010.
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Wei, James. Product Engineering. Oxford University Press, 2007. http://dx.doi.org/10.1093/oso/9780195159172.001.0001.
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The current chemical engineering curriculum concentrates on process: the efficient manufacturing in quantity of traditional chemical products such as ammonia and benzene. However, many chemical companies now invent and manufacture specialty products with particular properties such as pharmaceuticals, cosmetics, and electronic coatings, and their employees need to know how to design the products as well as manufacture them. James Wei, a famous chemical engineer, is writing this book to provide theories and case studies in product engineering the design of new, useful products with desired properties. The first section relates historical case studies of successful product invention and development by individuals and companies. The second part of the book describes the toolbox of molecular structure-property relations. A desired product needs to have certain properties (for example, phase transition or thermal properties) and the chemist must find or design a molecular structure with the required properties This section will instruct chemists in the analysis of structure and property information. The third section is concerned with the next stage: product research and design. It will discuss improving the desired product by additives and blending, among other strategies. It will also cover future challenges in product engineering.
Book chapters on the topic "Buildings – Thermal properties – Case studies"
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Santos da Silva, Paulo Ricardo. "Study of Thermal and Microbiological Behavior of Foods Submitted to Evaporative Cooling Process." In Handbook of Research on Advances and Applications in Refrigeration Systems and Technologies, 433–56. IGI Global, 2015. http://dx.doi.org/10.4018/978-1-4666-8398-3.ch012.
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Refrigeration is a widely used technique in the food industry to avoid microbiological spoilage of products. Several variables can affect the performance of chilling process, including the shape and the dimensions of the product, the thermophysical properties of the food and the cooling fluid. The evaporative cooling increases the rate at which the temperature of the products is reduced. However, it makes the refrigeration process more complex, since it involves the simultaneous mass and heat transfer. In this context, numerical simulation is a useful tool to analyze the processes because it allows investigating different operational conditions in a virtual environment, in a quick and inexpensive way. The goal of this chapter was to study the influence of process variables on thermal and microbiological behavior of minimally processed foods submitted to refrigeration process with and without evaporative cooling effect, by means of two case studies.
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Li, Hongzhi, and Yifan Zhang. "Heat Transfer and Fluid Flow of Supercritical Fluids in Advanced Energy Systems." In Advanced Applications of Supercritical Fluids in Energy Systems, 235–69. IGI Global, 2017. http://dx.doi.org/10.4018/978-1-5225-2047-4.ch008.
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This chapter aims to clarify the supercritical fluids thermal hydraulics characteristics including heat transfer, pressure drops and flow instabilities for the purpose of accurate design and efficient safe operation of advanced energy systems. At first, the convection heat transfer models considering the effect of nonlinear properties and the effect of buoyancy and acceleration have been provided and discussed. Secondly, the hydraulic resistance models for supercritical fluids have been selected and suggested for different conditions. Thirdly, the published models for supercritical flow instabilities based on four different regional partitions are summarized and clarified. At last, two typical case studies have been provided to further intuitively elaborate the thermal hydraulics of supercritical fluids within the advanced energy systems.
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Li, Hongzhi, and Yifan Zhang. "Heat Transfer and Fluid Flow Modeling for Supercritical Fluids in Advanced Energy Systems." In Handbook of Research on Advancements in Supercritical Fluids Applications for Sustainable Energy Systems, 388–422. IGI Global, 2021. http://dx.doi.org/10.4018/978-1-7998-5796-9.ch011.
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This chapter aims to model the supercritical fluids thermal hydraulics behaviors including heat transfer, pressure drops, and flow instabilities for the purpose of accurate design and efficient safe operation of advanced energy systems. At first, the convection heat transfer models considering the effect of nonlinear properties and the effect of buoyancy and acceleration have been provided and discussed. Secondly, the hydraulic resistance models for supercritical fluids have been selected and suggested for different conditions. Thirdly, the published models for supercritical flow instabilities based on four different regional partitions are summarized and clarified. At last, two typical case studies have been provided to further intuitively elaborate the thermal hydraulics of supercritical fluids within the advanced energy systems.
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Vishnu, S. B., and Biju T. Kuzhiveli. "Effect of Roughness Elements on the Evolution of Thermal Stratification in a Cryogenic Propellant Tank." In Low-Temperature Technologies [Working Title]. IntechOpen, 2021. http://dx.doi.org/10.5772/intechopen.98404.
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The cryogenic propulsion era started with the use of liquid rockets. These rocket engines use propellants in liquid form with reasonably high density, allowing reduced tank size with a high mass ratio. Cryogenic engines are designed for liquid fuels that have to be held in liquid form at cryogenic temperature and gas at normal temperatures. Since propellants are stored at their boiling temperature or subcooled condition, minimal heat infiltration itself causes thermal stratification and self-pressurization. Due to stratification, the state of propellant inside the tank varies, and it is essential to keep the propellant properties in a predefined state for restarting the cryogenic engine after the coast phase. The propellant’s condition at the inlet of the propellant feed system or turbo pump must fall within a narrow range. If the inlet temperature is above the cavitation value, cavitation will likely to happen to result in the probable destruction of the flight vehicle. The present work aims to find an effective method to reduce the stratification phenomenon in a cryogenic storage tank. From previous studies, it is observed that the shape of the inner wall surface of the storage tank plays an essential role in the development of the stratified layer. A CFD model is established to predict the rate of self-pressurization in a liquid hydrogen container. The Volume of Fluid (VOF) method is used to predict the liquid–vapor interface movement, and the Lee phase change model is adopted for evaporation and condensation calculations. A detailed study has been conducted on a cylindrical storage tank with an iso grid and rib structure. The development of the stratified layer in the presence of iso grid and ribs are entirely different. The buoyancy-driven free convection flow over iso grid structure result in velocity and temperature profile that differs significantly from a smooth wall case. The thermal boundary layer was always more significant for iso grid type obstruction, and these obstructions induces streamline deflection and recirculation zones, which enhances heat transfer to bulk liquid. A larger self-pressurization rate is observed for tanks with an iso grid structure. The presence of ribs results in the reduction of upward buoyancy flow near the tank surface, whereas streamline deflection and recirculation zones were also perceptible. As the number of ribs increases, it nullifies the effect of the formation of recirculation zones. Finally, a maximum reduction of 32.89% in the self-pressurization rate is achieved with the incorporation of the rib structure in the tank wall.
Conference papers on the topic "Buildings – Thermal properties – Case studies"
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Ni, Shuna, Ruben Van Coile, Danny Hopkin, Negar Elhami Khorasani, and Thomas Gernay. "Sensitivity Studies of the Resilience of RC Columns to Various Fire Scenarios." In IABSE Congress, New York, New York 2019: The Evolving Metropolis. Zurich, Switzerland: International Association for Bridge and Structural Engineering (IABSE), 2019. http://dx.doi.org/10.2749/newyork.2019.0732.
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<p>Reinforced concrete (RC) structures generally fare well under fire, but exhibit damage and residual deformations which require repairs. Besides the repair cost, the building downtime can also be expensive. However, current fire design approaches focus solely on life safety, and do not consider resilience. To improve post-fire performance of buildings, recover functionality, and facilitate fast reuse, an important step is to develop a predictive capability for the effect of a fire event on residual deformations and load-bearing capacity in structures. This research investigates the residual deformations in RC buildings after a fire, with a focus on the columns as one of the key structural members. The case study is a five-story RC frame building with a fire developing on the first story. Thermo-structural finite element analyses were used to analyze the columns performance under various fires. The sensitivity of the RC columns’ responses to main parameters related to fire characteristics, material properties and mechanical loading was analyzed. Based on the sensitivity studies, the most critical parameters were determined for the vulnerability of the RC columns to the different fire scenarios. These critical parameters will be used for the subsequent probabilistic damage evaluation of the RC columns and their design alternatives. The results will contribute to improved understanding of the effects of fire on the resilience of RC buildings and infrastructure, as well as the identification of designs which provide enhanced post-fire performance.</p>
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Cudd, Robert, Kevin Anderson, and Wael Yassine. "Evaluating the Energy Savings From Community Scale Solar Water Heating in Los Angeles County: Residential Case Studies." In ASME 2019 13th International Conference on Energy Sustainability collocated with the ASME 2019 Heat Transfer Summer Conference. American Society of Mechanical Engineers, 2019. http://dx.doi.org/10.1115/es2019-3960.
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Abstract Estimation of Energy Savings from Community Scale Solar Water Heating in Los Angeles County explores the extent to which community scale solar water heating systems, designed for residential structures in Los Angeles County and constructed from currently available technology, can displace natural gas for domestic water heating through a series of case studies. The effects of policy, urban form, and building characteristics on the performance of solar water heating systems, as well as community scale solar water heating’s potential to reduce emissions from the residential housing sector, are discussed herein. Three public and three private residential developments were selected as case studies for community scale solar water heating, with numbers of units and residents ranging from the tens to hundreds. These six cases were draw from the pool of approximately 19,000 “energy communities” in Los Angeles County, i.e. residential developments where the installation and operation of community scale solar water heating systems is broadly feasible. The six properties were also chosen to represent a cross-section housing stock and development patterns common in Los Angeles County, and different levels of suitability for solar water heating. The performance of and energy savings from solar water heating systems on each of these properties is then evaluated using the National Renewable Energy Laboratory’s System Advisor Model (NREL SAM). The results of the system simulations reveal how building characteristics and hot water demand affect the performance of community scale solar water heating systems. The case study sites’ system simulations show that residential developments with community scale solar water heating systems reach an average solar fraction of 50%. The results of the case studies indicate that community scale solar water heating is viable as an emissions reduction technology for the residential building sector in Mediterranean climates. However, side-by-side comparison with solar PV systems and other water heating technologies (such as grid-connected heat pumps) is necessary to determine optimality in terms of cost, emissions reduction, and thermal efficiency) in specific contexts.
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Peronto, John, Jordan Komp, and Alejandro Fernandez. "Tall Mass Timber Present and Future – 2 Case Studies." In IABSE Congress, New York, New York 2019: The Evolving Metropolis. Zurich, Switzerland: International Association for Bridge and Structural Engineering (IABSE), 2019. http://dx.doi.org/10.2749/newyork.2019.0655.
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<p>According to the 2018 UN Global Status Report, “buildings construction and operations accounted for 36% of global final energy use and nearly 40% of energy-related carbon dioxide (CO2) emissions in 2017”. [1] In a society leaning towards sustainable practices and efficiency, the improved structural properties of mass timber compared to traditional wood construction present a unique opportunity to add a sustainable material to the designer’s palette. This paper will focus on three subject areas:</p> <ul> <li>Current code challenges and developments related to the IBC</li> <li>Ascent, a 21-story mass timber tower currently underway in Milwaukee, WI. Upon completion, Ascent would be the tallest timber building in the Western Hemisphere. In addition to discussing the structural engineering principals behind the tower design, the team will elaborate on the current challenges associated with a project of this magnitude.</li> <li>River Beech, a research project centered on an 80-story all timber tower that pushes the limits of mass timber construction to pinpoint technical challenges that require future research. River Beech incorporates a high level of prefabrication and modularization, and utilizes a high degree of automation common to the mass timber construction fabrication process.</li> </ul> <p>The authors, based on their experience during the design of the case studies referenced above, will present an innovative technology capable of addressing the urban challenges related to building in a 21st century metropolis, while incorporating a sustainable and accessible material.</p>
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Luo, Zhixing, Yunlin Sun, Peng Liu, and Junfan Lu. "Application of New Timber Structure Building Envelope in China’s Solar Buildings." In ASME 2013 7th International Conference on Energy Sustainability collocated with the ASME 2013 Heat Transfer Summer Conference and the ASME 2013 11th International Conference on Fuel Cell Science, Engineering and Technology. American Society of Mechanical Engineers, 2013. http://dx.doi.org/10.1115/es2013-18312.
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Sustainable development could be seen as indispensable condition for survival of civilization. The development of timber products is a new paradigm in material and building science research in China, requiring the accounting for carbon emissions, carbon sequestration, material embodied energy, and material thermal properties for this renewable resource. This paper studies the application of the timber lattice wall in Chinese solar buildings. Firstly, it is analyzed timber structural form and mechanical property of the multi-ribbed composite wall, proving its high anti-seismic property and firmness by finite element modeling. Secondly, the timber structure filled with wheat straw brick contributes to low U-value of the wall, which is only 0.3 Watts per square meter per degree Celsius and far better than the code of Chinese building, greatly promoting building energy efficiency. Besides, the timber structure and straw brick are both “Cradle to Cradle” materials and reduce carbon emission compared to common building envelope. In the end, the paper is analyzed the promising market of the multi-ribbed composite wall for its competitive price and outstanding environmental performance.
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Camilleri, Lawrence, Arthur Watson, Yan Liu, and Mohammed El-Gindy. "Keep Your ESPs Running: Case Studies Exhibiting a Holistic Methodology for Run-Life Improvement." In SPE Gulf Coast Section Electric Submersible Pumps Symposium. SPE, 2021. http://dx.doi.org/10.2118/204483-ms.
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Abstract Build a more robust ESP or reduce the stress it endures? Run-life improvement requires finding the right balance to suit the local well conditions and economics. Utilizing key case studies, the paper examines how operational stress caused by low flow rates can be avoided with the correct utilization of instrumentation, surveillance, and automation thereby providing practical solutions for extending the run life of already installed ESPs. The method starts with an extensive review of ESP failure mechanisms and their causes, supported by case studies and pictures illustrating the symptoms that can be observed during dismantling. This holistic technique is supported by several case studies. The common "thread" found on most failure mechanisms is temperature rise inside the ESP, which deteriorates properties of materials, including polymer insulation, elastomer seals, and metallic parts. Heat rise is attributed to three main causes: motor thermal losses, pump hydraulic losses, and frictional heat. Case studies and data sets are provided to confirm that a paradigm shift in mitigation improvement can be achieved by automating the identification of low flow events utilizing a downhole real-time flowmeter. Three reasons are given. Firstly, it is a leading indicator, whereas surface flow meters and temperature sensors are lagging indicators due to pump-up time and heat exchange respectively. Secondly, automation enables more consistent and cost-effective identification in large ESP populations. Thirdly, it enables deeper diagnostics of the cause of low flow (i.e., gas lock versus slugging, and even the source of slugging such as horizontal lateral versus production tubing). The authors provide an exhaustive list of case studies identifying sand fallback and scale as well as low flow causes and how they can be diagnosed, including differentiation between ESP, wellbore hydraulics, and reservoir inflow causes (e.g. depletion and skin.) Over the last 30 years, improvements in design and materials have tripled ESP run lives. Therefore, many fields attain six-year average run lives and 90-day survivability of 98%. Nevertheless, economics have tightened, which has raised the bar, and therefore, many operators still suffer uneconomical run lives. Case studies indicate that the next step-change in run life improvement will require a reduction in environmental stresses by mitigating the effect of low-flow events, scale, and sand.
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Moaveni, Saeed, and Michael C. Watts. "Using a Windbreak to Improve the Thermal Performance of a Flat Plate Solar Collector: A Feasibility Study." In ASME 2011 5th International Conference on Energy Sustainability. ASMEDC, 2011. http://dx.doi.org/10.1115/es2011-54862.
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During the past few decades, a wide range of studies have been performed to improve the performance of flat plate solar collectors by either reducing the heat loss from a collector or by increasing the amount of solar radiation absorbed by the absorber plate. Examples of these studies include adding transparent honeycomb to fill the air gap between the glazing and absorber plate to reduce convective heat loss, replacing the air in the gap by other gases such as Argon, Krypton, Xenon and Carbon Dioxide, or adding a chemical coating such as Copper Oxide to increase absorbtance and reduce the emittance of the absorber plate. While these methods improve the collector’s efficiency, they focus primarily on limiting the natural convection that occurs in the collector cavity, or on improving the optical properties of the absorber or glazing. None of these studies have addressed the problem of heat loss due to forced convection to the surrounding ambient air in any detail. Yet, research has shown that forced convection will contribute significantly to the heat loss from a collector. Windbreaks have traditionally been used to direct wind to protect farmland, and to direct wind drifts and sand dunes. Windbreaks also have been shown to provide protection for homes from winter winds which result in reduced heating costs for buildings. While windbreaks have been traditionally used for large scale applications, there is reason to believe that similar benefits can be expected for scaled down applications such as adding a windbreak along side of a flat-plate solar collector. In this paper, we examine the feasibility of using a windbreak to provide a flat plate solar collector protection from the wind in order to improve its performance. A series of experiments were performed wherein the thermal performance of two flat-plate collectors — one without a windbreaker and one with a windbreaker — were measured. The results of these experiments are reported in this paper and the need for further studies to explore different windbreak configurations is discussed.
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DiCarlo, Anthony A., and Rickey A. Caldwell. "Gradient Based Soil Thermal Conductivity Optimization for Ground Source Heat Exchangers." In ASME 2018 12th International Conference on Energy Sustainability collocated with the ASME 2018 Power Conference and the ASME 2018 Nuclear Forum. American Society of Mechanical Engineers, 2018. http://dx.doi.org/10.1115/es2018-7418.
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In geothermal heating and cooling, there exists an opportunity to improve the efficiency by utilizing non-uniform soil properties of a ground source heat exchanger during installation. This paper presents a gradient approach based upon finite element mathematics to determine an optimal distribution of heterogeneous soils with varying thermal conductivities. The numerically simulated case studies demonstrate the good performance of this algorithm to minimize the cross-talk of heat flux between pipes and maximize the overall efficiency.
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Ruiz-Apilánez, Borja, Eloy Solís, Vicente Romero de Ávila, Carmen Alía, Irene García-Camacha, and Raúl Martín. "Spatial distribution of economic activities in heritage cities: The case of the historic city of Toledo, Spain." In 24th ISUF 2017 - City and Territory in the Globalization Age. Valencia: Universitat Politècnica València, 2017. http://dx.doi.org/10.4995/isuf2017.2017.5164.
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Spatial distribution of economic activities in heritage cities: The case of the historic city of Toledo, Spain. Borja Ruiz-Apilánez¹, Eloy Solís¹, Vicente Romero de Ávila², Carmen Alía¹ ¹Universidad de Castilla-La Mancha, Escuela de Arquitectura. Avda. Carlos III, s/n ES-45071 Toledo ²Universidad de Castilla-La Mancha. Escuela de Ingenieros de Caminos. Avda. Camilo José Cela, s/n ES-19071 Ciudad Real E-mail: borja.ruizapilanez@uclm.es, eloy.solis@uclm.es, vicente.romeroavila@uclm.es, carmen.alia@alu.uclm.es Keywords (3-5): Urban Economics, Space Syntax, Heritage Cities, Spain Conference topics and scale: Urban form and social use of spacePrevious studies have shown: (a) that Space Syntax theories and tools can be helpful to explain pedestrian flows and the spatial distribution of economic activities in cities and other human settlements (Chiaradia et al., 2009; Perdikogianni, 2003; Vaughan et al., 2013), and (b) that the economy of many heritage cities highly depends on tourism (Ashworth and Tunbridge, 2000; Kemperman et al., 2009). Assuming that, in this particular type of human settlements, heritage buildings such as the cathedral, the town hall, and other similar constructions operate as tourist attractors, this research investigates to what extent the location of these buildings, together with the two main syntactic properties of the elements of the street network—integration and choice—can describe the spatial distribution of economic activities in touristic heritage cities, using the UNESCO Heritage site of Toledo, Spain, as case study. In order to investigate this question, each segment of the street network has been characterized with four main values: (1) economic activity, (2) spatial integration, (3) spatial choice, and (4) heritage intensity. The first value, economic activity, represents the presence or absence of economic activity in the buildings that are accessible through each corresponding street segment. The second value, spatial integration, accounts for the integration values that each segment has at two different scales—the neighborhood and the whole city. The third value, spatial choice, considers the choice values that each segment has, again, at these two scales. The fourth value, heritage intensity, reflects the proximity of listed building to each individual street segment. Street audits were used to record the economic activities taking place in the ground floors and upper floors of the buildings within the historic city. Space Syntax analysis was used to determine the different integration and choice values for each street segment; and GIS tools were used to establish their heritage intensity. Afterwards, statistical analysis was employed to investigate the relationships among these four variables, showing how the distribution of economic activity in the street network of the historic city of Toledo can be well explained by the other three variables—spatial integration, spatial choice and heritage intensity.References Ashworth, G.J., Tunbridge, J.E. (2000) The Tourist-historic City: Retrospect and Prospect of Managing the Heritage City. Routledge. Chiaradia, A., Hillier, B., Schwander, C., Wedderburn, M. (2009) ‘Spatial Centrality , Economic Vitality / Viability. Compositional and Spatial Effects in Greater London’, in Proceedings of the 7th International Space Syntax Symposium. 1–19. Kemperman, A.D.A.M., Borgers, A.W.J., Timmermans, H.J.P. (2009) ‘Tourist shopping behavior in a historic downtown area’. Tourism Manaement. 30, 208–218. Perdikogianni, I. (2003) ‘Heraklion and Chania: A study of the evolution of their spatial and functional patterns’, in 4th International Space Syntax Symposium. London, p. 19.1-19.20. Vaughan, L., Dhanani, A., Griffiths, S. (2013) ‘Beyond the suburban high street cliché - A study of adaptation to change in London’s street network: 1880-2013’. Journal of Space Syntax 4.
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Lin, Bochuan, Heng Ban, Chao Li, Rosalia N. Scripa, Ching-Hua Su, and Sandor L. Lehoczky. "Method for Obtaining Thermal Conductivity From Modified Laser Flash Measurement." In ASME 2005 International Mechanical Engineering Congress and Exposition. ASMEDC, 2005. http://dx.doi.org/10.1115/imece2005-79932.
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Laser flash method is commonly used to measure the thermal diffusivity of solids. In the original thermal analysis, adiabatic boundary conditions were used and the time for sample rear surface temperature to reach 50% of maximum value was used to calculate the thermal diffusivity. Later other boundary conditions were included in the analysis to compensate for the heat loss. The laser flash method can be modified to determine the thermal conductivity by comparing the temperature rise of the sample with a standard sample, both of which are coated to ensure identical surface emissivity. In our previous studies of applying the laser flash method to semiconductor melts, we have shown that it is possible to obtain thermal conductivity, specific heat capacity and thermal diffusivity from the experimental data. In these studies, the melt sample was sealed in a specially-designed fused silica cell. The heat transfer between melt sample and the fused silica cell allows the thermal conductivity to be included in the analysis. Therefore, the temperature response of the melt sample was controlled not only by the thermal diffusivity and conductivity of sample, but also by the thermal properties of fused silica cell. Using a computational fitting process, we obtained both thermal diffusivity and thermal conductivity of the sample. In this paper, an analytic solution for the transient heat transfer inside the sample and fused silica cell was developed. The influence of fused silica cell was included and the heat transfer to fused silica cell had a significant effect on the time-temperature response of the sample. Therefore, the rear surface temperature of the sample, described by an analytical solution, could be used to obtain both thermal diffusivity and thermal conductivity of the sample with known properties of the fused silica cell. The results indicated that this method was applicable for a wide range of sample and cell properties. The original solution for laser flash method became an extreme case in the current theory
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Gomez-Ramirez, David, Srinath V. Ekkad, Brian Y. Lattimer, Hee-Koo Moon, Yong Kim, and Ram Srinivasan. "Separation of Radiative and Convective Wall Heat Fluxes Using Thermal Infrared Measurements Applied to Flame Impingement." In ASME 2015 International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, 2015. http://dx.doi.org/10.1115/imece2015-52322.
Full textAbstract:
Flame impingement is critical for the processing and energy industries. The high heat transfer rates obtained with impinging flames are relevant in metal flame cutting, welding, and brazing; in fire research to understand the effects of flames on the structures of buildings; and in the design of high temperature combustion systems. Most of the studies on flame impingement are limited to surfaces perpendicular to the flame, and measurements are often performed using heat flux sensors (such as Schmidt-Boelter heat flux transducers) at discrete locations along the target surface. The use of in-situ probes provides high accuracy but heavily limits the spatial resolution of the measurement. Moreover, flame radiation effects are often neglected, due to the small contribution in non-luminous flames, and the entire heat flux to the target is assumed to be due to convection. Depending on the character of the flame and the impingement surface, local radiative heat transfer can be significant, and the contribution of radiation effects has not been fully quantified. This study presents a novel non-intrusive method with high spatial resolution to simultaneously determine the convective and radiative heat fluxes at a wall interacting with a flame or other high temperature environment. Two initial proof of concept experiments were conducted to evaluate the viability of the technique: one consisting of a flame impinging normal to a target and another with a flame parallel to the target surface. Application of the methodology to the former case yielded a stagnation convective heat flux in the order of 106kWm−2 that decreased radially away from the stagnation point. The radiation field for the direct impingement case accounted on average for 4.4% of the overall mean heat flux. The latter experiment exemplified a case with low convective heat fluxes, which was correctly predicted by the measurement. The radiative heat fluxes were consistent between the parallel and perpendicular cases.