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The Effect of Thermal Load Configurations on Passive Chilled Beam PerformanceNelson, Ian 1982- 14 March 2013 (has links)
This dissertation presents the findings of a study to quantify the effect of heat source configurations on the performance of passive chilled beams. Experiments in a thermally controlled test room were conducted using thermal manikins as heat sources cooled with a 0.6 m by 2.4 m beam. The thermal manikins were arranged in a symmetric and an asymmetric configuration and tested over a range of input power to simulate a low-to-high load heat distribution of an indoor space. A computational fluid dynamics (CFD) model was developed in Star CCM+ v6.06 and used for further analysis of the flow field and to predict additional spatial arrangements of the beam, interior dimensions, and heat source configurations. The CFD model implemented a calculation for the beam cooling capacity to predict the beam performance based on the room thermal conditions.
The experimental data revealed an average reduction of 15% in the passive beam cooling capacity for the asymmetrically configured thermal manikins compared to the symmetric arrangement. The CFD model was validated with the experimental data and predicted the asymmetric heat source beam performance reduction to be 17%. The reduction in performance based on the heat source arrangement was found with analysis of the CFD simulations to be a result of the above-beam air velocity field. The unbalanced thermal manikin configuration generated an unbalanced flow condition at the inlet of the beam that resulted in the room air circumventing the inlet of the passive beam, as compared to the inlet velocity field of the symmetric configuration.
Additional configurations were investigated with the CFD model to include the beam position, floor area, ceiling height, and thermal manikin arrangements. The simulation results were analyzed by comparing the efficiency of beam performance using the beam cooling capacity calculation for each scenario. The predictions of additional configurations found that the efficiency increased when the beam was perpendicular to a group of heat sources and the changes in beam performance with heat source configurations was not affected by the interior dimensions of the space. However, the resulting thermal conditions in the occupied zone for the beam positions of highest efficiency may negatively impact the thermal comfort of occupants.
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MILJÖCERTIFIERING MED MILJÖBYGGNAD : FÖRSLAG FÖR LÖSNING AV PROBLEMET MED UPPFYLLNAD AV KRAVEN PÅ DAGSLJUS OCH SOLVÄRMELAST / ENVIRONMENTAL CERTIFICATION WITH MILJÖBYGGNAD : PROPOSAL FOR SOLUTION OF THE PROBLEM WITH FULFILLMENT OF THE CLAIMS OF DAYLIGHT AND SOLAR HEAT LOADJohansson, Pontus, Alvarsson, Daniel January 2015 (has links)
Syfte: I dagens samhälle har det blivit mer intressant att bygga med en miljö-certifiering, detta leder till att byggentreprenörer ställs inför tekniska svårigheter vid både projektering och produktion för att kraven ska uppfyllas. I denna rapport kommer svårigheterna med solvärmelast och dagsljus behandlas då de kan vara ett problem. Målet med denna rapport är att ”Belysa hur kraven på dagsljus och solvärmelast enligt miljöcertifieringssystemet Miljöbyggnad kan lösas”. Metod: Kvalitativ data samlades in via intervjuer för att få svar på frågeställningarna. Intervjuerna genomfördes i huvudsak på plats hos respektive persons företag. En hög validitet uppnåddes genom att intervjufrågorna strukturerades och hade koppling till frågeställningar och mål. Reliabiliteten stärktes genom att intervjuerna spelades in och det gick att hitta samband mellan svaren. Resultat: Kravnivåerna i Miljöbyggnad är BBR:s krav i grunden för de flesta indikatorer vilket motsvarar BRONS-nivån i Miljöbyggnad. För indikatorn dagsljus skulle SILVER vara lite bättre än BRONS och för GULD krävs datorsimuleringar samt enkätundersökning eller egendeklaration. För Indikatorn solvärmelast finns inget grundkrav i BBR då det endast står att solvärmetillskottet ska begränsas. När kravnivåerna för solvärmelast togs fram användes persienner för att ta reda på rimliga nivåer. Det kan uppstå problem med att uppfylla kraven för solvärmelast och dagsljus om arkitekten inte har tillräcklig kunskap om Miljöbyggnad. Placering av byggnader och fönster är också problematiskt eftersom byggnader inte bör ligga för nära varandra för att tillräckligt med dagsljus ska komma in i byggnaden. Mycket fönster i söderriktning kan innebära mycket solinstrålning vilket kan ge problem med att klara solvärmelasten. De lösningar som denna rapport har fått fram är att det ska finnas en dialog mellan ansvariga i projekten för att hitta pareto-optimala lösningar. Det går att sänka kravet på en indikator och höja kravet på en annan för att sammanlagt få det byggnadsbetyg som önskas. Solvärmelastens krav kan lösas med hjälp av olika sorters solskydd. Det går även att ändra fönstrets typ, storlek eller antal. Konsekvenser: Den slutsats som går att dra efter att arbetet blivit färdigställt, är att fönster påverkar indikatorerna solvärmelast och dagsljus mest. För att båda de kraven ska bli uppfyllda och få ett högt betyg, är det lämpligt att använda solskydd för att minska solvärmelasten. En rekommendation är också att beställarens arkitekt detaljberäknar indikatorerna innan förfrågningsunderlaget går ut, då det oftast är i början av byggprocessen som de större problemen kan undvikas. Begränsningar: Arbetet begränsas till att behandla indikatorerna solvärmelast och dagsljus i miljöcertifieringssystemet Miljöbyggnad. Lösningar för kravnivåerna detaljstuderas inte. Undersökningsstrategin begränsas till att bara innehålla en kvalitativ metod. Nyckelord: Dagsljus, Fönster, Miljöbyggnad, Solvärmelast / Purpose: Society has become more interested in building with an environmental certification system, which leads to that building engineers are facing technical difficulties in both planning and production to meet the requirements. This thesis addresses the technical difficulties with solar heat load and daylight in the environmental certification system Miljöbyggnad. The purpose of this thesis is to “Illustrate how the demands of daylight and solar heat load in Miljöbyggnad can be solved”. Method: Qualitative data were collected through interviews to obtain answers concering the issues. The interviews essentially took place at each person’s company. High validity was achieved by the interview questions that were structured and linked to the issues and the purpose of this thesis. To increase the reliability, interviews were recorded and it was possible to find correlations between the answers. Findings: The BRONZE level in Miljöbyggnad is basically BBR:s requirements for most of the indicators. The SILVER level for the indicator daylight were supposed to be better than BRONZE and GOLD requires simulations and pleased residents. It is not possible to find requirements for solar heat load in BBR. When the requirements for this indicator in Miljöbyggnad was set, sun-blinds were used. There may be problems in meeting the requirements for solar heat load and daylight if the architects do not have the sufficient knowledge of Miljöbyggnad. The placement of buildings and windows are also problematic because the distance between the buildings can affect daylight problems. If there are a lot of windows in the south direction, the solar gain may cause difficulty to solve the requirements for solar heat load. The solutions this thesis submits are, to have a dialogue between the involving people in the projects to find pareto-optimal solutions. It is possible to reduce the require-ments for one indicator and raise the requirements for another to get the total building-rating as required. The requirements for solar heat load can be solved by using different kinds of shading devices. It is possible to change the type of windows, size of the windows and the amounts of windows. Implications: The conclusions are that the windows affect the indicators solar heat load and daylight very much. To solve the requirements and get a high rating on both indicators, it is appropriate to use any kind of shading devices. We also recommend that the architect calculates the indicators in detail before the tender document is ready, to avoid major problems. Limitations: To limit the extensive work it was necessary to focus on the indicators solar heat load and daylight in the environmental certification system Miljöbyggnad. The solutions for the indicators levels were not studied in details. The investigation method was limited to only use qualitative interviews. Keywords: Daylight, Miljöbyggnad, Solar heat load, Windows
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Investigation on methods to improve heat loadprediction of the SGT-600 gas turbineFarhanieh, Arman January 2016 (has links)
In modern gas turbines, with the increase of inlet gas temperature to raise thework output, the importance of accurate aero-thermal analysis has become of vitalimportance. These analysis are required for temperature prediction throughoutthe turbine and to predict the thermal stresses and to estimate the cooling requiredfor each component.In the past 20 years, computational fluid dynamics (CFD) methods have becomea powerfool tool aero-thermal analysis. Due to reasons including numericallimitation, flow complications caused by blade row interactions and the effect offilm cooling, using simple steady state CFD methods may result in inaccuratepredictions. Even though employing transient simulations can improve the accuracyof the simulations, it will also greatly increase the simulation time and cost.Therefore, new methods are constantly being developed to increase the accuracywhile keeping the computational costs relatively low. Investigating some of thesedeveloped methods is one of the main purposes of this study.A simplification that has long been applied in gas turbine simulations hasbeen the absence of cooling cavities. Another part of this thesis will focus onthe effect of cooling cavities and the importance of including them in the domain.Therefore, all transient and steady state simulations have been examined for twocases; a simplified case and a detailed case. The results are then compared tothe experimental measurements to evaluate the importance of their presence inthe model. The software used to perform all simulations is the commercial codeANSYS CFX 15.The findings suggest that even though including cooling cavities would improvethe results, the simulations should be run in transient. One important finding wasthat when performing transient simulations, especially the Time Transformationmethod, not only is the pitch ratio between every subsequent blade row important,but also the pitch ratio between the stators is highly influential on the accuracyof the results.
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An Online Machine Learning Algorithm for Heat Load Forecasting in District Heating SystemsProvatas, Spyridon January 2014 (has links)
Context. Heat load forecasting is an important part of district heating optimization. In particular, energy companies aim at minimizing peak boiler usage, optimizing combined heat and power generation and planning base production. To achieve resource efficiency, the energy companies need to estimate how much energy is required to satisfy the market demand. Objectives. We suggest an online machine learning algorithm for heat load forecasting. Online algorithms are increasingly used due to their computational efficiency and their ability to handle changes of the predictive target variable over time. We extend the implementation of online bagging to make it compatible to regression problems and we use the Fast Incremental Model Trees with Drift Detection (FIMT-DD) as the base model. Finally, we implement and incorporate to the algorithm a mechanism that handles missing values, measurement errors and outliers. Methods. To conduct our experiments, we use two machine learning software applications, namely Waikato Environment for Knowledge Analysis (WEKA) and Massive Online Analysis (MOA). The predictive ability of the suggested algorithm is evaluated on operational data from a part of the Karlshamn District Heating network. We investigate two approaches for aggregating the data from the nodes of the network. The algorithm is evaluated on 100 runs using the repeated measures experimental design. A paired T-test is run to test the hypothesis that the the choice of approach does not have a significant effect on the predictive error of the algorithm. Results. The presented algorithm forecasts the heat load with a mean absolute percentage error of 4.77\%. This means that there is a sufficiently accurate estimation of the actual values of the heat load, which can enable heat suppliers to plan and manage more effectively the heat production. Conclusions. Experimental results show that the presented algorithm can be a viable alternative to state-of-the-art algorithms that are used for heat load forecasting. In addition to its predictive ability, it is memory-efficient and can process data in real time. Robust heat load forecasting is an important part of increased system efficiency within district heating, and the presented algorithm provides a concrete foundation for operational usage of online machine learning algorithms within the domain.
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MEASUREMENT AND MODELLING OF ICE RINK HEAT LOADSKarampour, Mazyar January 2011 (has links)
Ice rinks are among the most energy intensive public buildings in developed and developing countries. According to a research on Swedish ice rinks; a typical ice rink consumes approximately 1185 MWh/year which leads to more than 300 GWh/year for the 342 Swedish indoor ice rinks. The refrigeration system is usually the largest consumer by 43% average share of the total energy consumption. To decrease the refrigeration system energy demand, there are a variety of energy efficiency techniques known and available but the key to select the best ones is finding the major heat loads on the ice sheet and refrigeration system, which is unique for each ice rink. To fulfil this objective and in addition to review literature, this study has two main approaches. The first approach is to measure and evaluate the performance of the refrigeration system in two ice rinks, called Norrtälje and Älta. The estimated cooling capacity is approximately equal to the total heat load on the ice plus the heat gains in the distribution system. This goal has been accomplished by using a performance analyser called “ClimaCheck” which is based on an “internal method” because it uses the compressor as an internal mass flow meter and consequently, there is no need for an external one. The refrigerant mass flow rate is calculated by an energy balance over the compressor. By knowing the mass flow, enthalpy of the refrigerant, etc. the cooling capacity and COP of the system can be calculated. While the total heat load is known by the first approach, the second approach tries to discover different heat loads shares by analytical modelling. The measured physical and thermodynamical parameters plus the ice rink geometrical characteristics are input to the heat transfer correlations to estimate the heat load magnitude. The results of the measurements show that the total energy consumption in Norrtälje is about two third of Älta. The main reasons for this less energy consumption are smarter control systems for compressors and pumps, better ventilation distribution design and 1°C-2°C higher ice temperature. Analytical modelling for a sample day has estimated that about 84% of the total heat loads is originated from the heat loads on ice sheet while the distribution system causes the remaining 16%. Moreover, calculations show that convection plus small portion of condensation (altogether 36%), radiation (23%), ice resurfacing (14%) and lighting (7%) are the largest heat loads in winter while in summer condensation is another significant heat load (10%). Comparing two six-hour periods, one without ice resurfacing and four resurfacings in the second one, 30% more cooling demand has been calculated for the second period. Furthermore, it has been shown that the evaporator to brine is the contributor for 66% of the heat transfer resistances from ice to evaporator while brine to bottom ice and bottom to top ice accounts for 27% and 7% respectively. To conclude, a parallel “performance analysis of the refrigeration system” and “heat loads estimation” proves to be a useful tool for adopting proper design and control for energy efficient operation. / Stoppsladd financed by Swedish Energy Agency (Energimyndigheten) and Swedish Ice Hockey Association
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Fjärrvärmeanslutna passivhus : Fallstudie av värmelaster och innetemperaturer i fyra flerbostadshusNilsson, Daniel January 2012 (has links)
Intresset kring lågenergibyggnader blir allt större och så kallade passivhus, med god isolering, hög lufttäthet och värmeåtervinning, byggs i allt större utsträckning i Sverige och andra europeiska länder. Vissa frågetecken har dock uppkommit kring inomhusklimatet i husen och risken för både under- och övertemperaturer. En annan viktig aspekt är hur husens egenskaper påverkar värmelasterna och hur detta i sin tur påverkar energiförsörjningssystemet. I detta examensarbete undersöks dessa båda aspekter – värmelastegenskaper och innetemperaturer – i fyra likadana nybyggda flerbostadshus i Falkenberg. Mätvärden från husens tekniska system, inklusive lufttemperaturmätningar i samtliga lägenheter, analyseras. Husen består av totalt 108 lägenheter, värms med fjärrvärme och använder ca 50 kWh/m2 Atemp årligen. Värmelastegenskaperna kännetecknas framförallt av låga effektbehov för både uppvärmning och varmvatten samt relativt stora svängningar över dygnet. Husen tycks vara känsligare för variationer i interntillskott än konventionella hus, vilket leder till regelbundna svängningar i effektbehovet för uppvärmning, med en topp under natten och morgonen. Detta leder till förstärkta svängningar i fjärrvärmenätet, vilket skulle kunna undvikas med hjälp av effektstyrning. Passivhusens stora termiska tröghet talar för en sådan möjlighet. Även innetemperaturen uppvisar regelbundna dygnsvariationer, som kan vara något större än i vanliga hus. Låga temperaturer förekommer tidvis under vintern, men resultaten pekar inte på några brister i de tekniska systemen. Temperaturen på sommaren är inte högre än i andra hus, och övertemperaturer tycks inte vara något stort problem i dessa hus. Det kan dock finnas en möjlighet att minska risken för övertemperaturer ytterligare genom användning av nattkyla under varma perioder. Denna möjlighet kan vara ett sätt att utnyttja passivhusens speciella egenskaper för att ytterligare förbättra konceptet. / There is today an increasing interest in low-energy buildings, and the so-called “passive houses” are becoming increasingly popular in Sweden and other European countries. There are however some concerns regarding the indoor climate in these houses, notably the risk of too low indoor temperatures in the winter and too high temperatures in the summer. Another issue is the heat load characteristics of this type of buildings, and how these affect the energy systems. In this thesis, these two aspects – heat load characteristics and indoor temperatures – are analysed in four identical multi-family buildings in Falkenberg, Sweden, using measured values from the buildings’ technical systems and measured indoor air temperatures in all dwellings. The buildings are heated with district heating, comprise 108 dwellings in total and use approximately 50 kWh/m2 annually (space heating, hot water and electricity for building services). The heat loads are mainly characterised by low but varying heat demands for space heating and hot water. The buildings appear to have a higher than usual sensitivity for variations in heat from internal sources and solar gains, leading to regular variations in the heat demand for space heating and fluctuations in the total heat demand. These fluctuations, which may negatively affect the energy system, could be avoided by actively controlling the heat demand for space heating. There are also daily fluctuations in the indoor temperatures, but the buildings perform well in this aspect, with temperatures that stay within the acceptable range most of the time. The summer indoor temperatures do not get higher than in other buildings. A possibility for further improvement within this area could be the use of forced ventilation during the night in hot periods, and hence utilising the buildings’ well insulated and airtight building envelope to keep heat out during the day. This possibility might further improve the passive house concept.
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The heat load in district heating systemsWerner, Sven January 1984 (has links)
This thesis considers the composition of the daily heat load in six Swedish district heating systems supplying heat for space heating and hot water supply. The analysis was performed by bringing together a heat load model and series of daily heat load observations covering periods ranging from five to eleven years. The influences of transient heat transmission, solar gain, and wind infiltration are found to be significant but small. It is shown that a natural self control of water radiators affects the magnitude of these influences when the control systems are incomplete. The annual fraction of each heat load component, the composition of the heat load duration graph, and the long term changes in heat consumption are presented. Furthermore, the heat load composition estimated facilitates future heat load simulations in order to quantify the outcome of various energy conservation measures with respect to reductions in design heat load and annual heat demand.
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Contraintes thermiques dans les dépôts de couches minces pour les optiques rayons-X sous forte charge thermique / Thermal stress issues in thin film coatings of X-ray optics under high heat loadCheng, Xianchao 25 September 2014 (has links)
Les optiques multicouches pour rayons-X sont généralement constituées de centaines de périodes de couches alternées. L'épaisseur d'une période est de quelques nanomètres. Une multicouche est souvent déposée sur un substrat de silicium avec une taille typique de 60 × 60 × (60~300) mm3. Le rapport de dimensions (~107) entre la taille de l'optique et de l'épaisseur de l'empilement est très élevé et il peut conduire à un très grand nombre d'éléments (~1016). Certains éléments spéciaux avec fonctions de couche sont disponibles dans ANSYS (de 2011), ce qui signifie que les propriétés de chaque couche peuvent être définies. Par l'utilisation des éléments nommés « layer-functioned », le modèle d'analyse thermique-structurelle a été mise en œuvre pour les optiques multicouches. Le nombre d'éléments est réduit par un facteur supérieur à 30 et le nombre effectif de sous-couches gérables par les ordinateurs actuels augmente beaucoup. Basé sur la modèle d'éléments finis de l'optique multicouche, la distribution tridimensionnelle non-uniforme de température peut être simulée avec des paramètres variables de charge thermique, de conditions de refroidissement, de propriétés des matériaux, de géométries du substrat et des films de revêtement. Les contraintes et déformations thermiques peuvent être résolues quantitativement.Des miroirs à réflexion totale et des monochromateurs multicouches refroidis à l'eau et à l'azote liquide ont été étudiés avec des paramètres typiques de charge thermique, de refroidissement et de géométrie. Les effets de refroidissement de l'optique et de la charge thermique du faisceau de rayons-X ont été décrits. Il est montré que les influences de la température sur le revêtement et la déformation sont négligeables. La contrainte dans le substrat n'est que légèrement augmentée (<0.1%). Cependant, des fortes contraintes sont induites dans les couches en raison de la différence de CTE, ce qui peut être critique pour la survie de l'optique. Pour la condition de refroidissement à l'eau, la couche est sous contrainte de compression de plusieurs dizaines de MPa, ce qui est normalement inférieur à la résistance du matériau de la couche. Pour la condition de refroidissement à l'azote liquide, cependant, une grosse contrainte de traction de plusieurs centaines de MPa apparait dans la couche lorsque l'optique est refroidie jusqu'à la température de l'azote liquide (80 K). Cette contrainte de traction peut dépasser la résistance à la traction (UTS) pour certains types de matériaux de couche. La contrainte thermique dans l'optique multicouche dépend de la différence de CTE entre le matériau de la couche et le matériau du substrat, mais elle est indépendante de la différence des CTE entre les différentes sous-couches. En principe, pour minimiser la contrainte thermique, le matériau de revêtement doit avoir un CTE proche de celle du substrat, un module de Young et un coefficient de Poisson plus petits. En outre, une grande résistance du matériau de la couche est bénéfique pour sa capacité à résister à la contrainte thermique.Pour obtenir des informations appropriées sur le comportement des multicouches sous l'influence de la charge thermique, des propriétés telles que le module de Young, le ratio entre CTE et module de Poisson des multicouches sont déterminés indirectement en mesurant la variation de la courbure due au changement de température. Des couches simples de B4C, Pd et Cr et des multicouches [Pd/B4C] d'épaisseurs de l'ordre du nanomètre sont préparées et mesurées. Les résultats expérimentaux montrent que tous les matériaux étudiés présentent un CTE et/ou un module de Young inférieur par rapport aux données dans la littérature. Cela est particulièrement vrai pour les couches minces de B4C. Par conséquent, la contrainte thermique réelle et la contrainte dans les couches de revêtement d'un miroir ou de multicouches optiques sont sensiblement plus petites que les résultats calculés avec les propriétés des matériaux massifs. / Multilayer optics for X-rays typically consists of hundreds of periods of alternating sub-layers coated on a silicon substrate. The thickness of one period of sub-layers is a few nanometers. The silicon substrate is typically a block of 60 mm large, 60 mm wide and 60 to 300 mm long. The high aspect ratio (~107) between the size of the optics and the thickness of the multilayer can lead to a very large number of elements (~1016) for the numerical simulation (by FEA). Some special layer-functioned elements have been developed recently (in 2011) in ANSYS, which means the properties of each layer can be explicitly defined. In this work, the thermal-structural analysis model has been implemented for multilayer optics by use of these layer-functioned elements. The number of meshed elements is considerably reduced by a factor of more than 30 and the number of sub-layers feasible for the present computers is increased significantly. Based on the finite element model of multilayer optics, the non-uniform three-dimensional temperature distribution can be simulated with variable heat load parameters, cooling conditions, material properties and geometries of the substrate and the coating films. The thermal stress and deformation can be solved quantitatively.Single layer coated mirrors and multilayer monochromators cooled by water or liquid-nitrogen are studied with typical parameters of heat-load, cooling, and geometry. The effects of cooling-down of the optics and the X-ray beam heat-load are described. It is shown that the influences from the coating on temperature and deformation are negligible. The stress in the substrate is only slightly increased (<0.1%). However, large layer stresses are induced due to the different thermal expansion coefficients (CTE) between the layer and substrate materials, which are the critical issues for the survival of the optics. For the water cooling condition, the layer is under compressive stress of tens of MPa which is normally less than the strength of the layer material. For the liquid-nitrogen cooling condition, however, large tensile stress of several hundreds of MPa is formed in the layer as the optics is cooled more than 200 K down to the liquid-nitrogen temperature (80K). This tensile stress can exceed the ultimate tensile strength (UTS) for some kinds of layer materials. The thermal stress in multilayer optics depends on the difference in CTE between the layer material and the substrate material, but it is independent on the CTE difference between different sub-layers. In principle, to minimize the thermal stress, the coating material should have a CTE closer to that of the substrate, smaller Young's modulus and Poisson's ratio. Moreover, a higher strength of the layer material is beneficial for its ability to withstand the thermal stress.To acquire appropriate information about the behaviour of thin multilayer films under the influence of thermal loading, material properties such as Young's modulus, Poisson's ratio and CTE, of thin multilayer films are determined indirectly by measuring the curvature change due to uniform temperature change. B4C, Pd and Cr single layers and [Pd/B4C] multilayers of thicknesses in the nanometer range are prepared and measured. The experimental results show that all of the studied materials exhibit lower CTE and/or Young's modulus than expected from bulk data in the literature. This is particularly true for the thin B4C films. Therefore, the real thermal stress and strain in the coating layers of a mirror or multilayer optics are significantly smaller than the calculated results with bulk material properties.results with bulk material properties.
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Systémy chlazení pro polyfunkční objekty. / Cooling systems for polyfunctional object.Milatová, Adriána January 2019 (has links)
The diploma thesis deals with the design of cooling devices of a fourteen-storey polyfunctional building with administration part and housing units. The thesis describes the physical nature of cooling, the basic types and functions of cooling systems and legislation related to cooling devices. Two types of cooling systems are selected and developed for the assigned object at the building permit design level. The work includes calculations of all elements of individual systems. The purpose of this diploma thesis is the comparison of these variants and the evaluation of suitability for use on the individual parts of the assigned building. The variant chosen is elaborated at the level of the rea-lization project, including the drawing documentation.
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Energy Usage prediction model comparing Indoor Vs. Outdoor Ice RinksKhalid, Waqas January 2012 (has links)
Indoor ice rinks use 1091 MWh per annum for ice hockey based on statistics from over 100 Swedish ice rinks (Stoppsladd, 2011).The refrigeration system contributes 35 to75%( (Rogstam, 2010) of total energy usage in ice rinks with average value of 43% (Stoppsladd, 2010) for indoor to 75% for outdoor ice rinks. The basic aim of project is to reduce energy consumption in Swedish ice rinks and scope is for indoor and outdoor ice rinks in cold and mild summer climatic conditions like Sweden. To achieve target of energy reduction in ice rinks actual heat loads on outdoor bandy ice rink are being estimated along with performance analysis of refrigeration machine. The refrigeration system, heat loads on ice surface and their correlation is studied and analyzed in detail for Norrtälje Outdoor bandy ice rink for four warm days and whole season 2010-2011. The tricky and significant task of validation of input climate data for accurate heat loads calculations is completed with Swedish Metrological & Hydrological (SMHI) climate model data, correlations and related web based geographical data. The heat loads (conductive, convective and radiant) on outdoor bandy ice rink are calculated through thermodynamic relations with validated input climate data and measurements where as refrigeration system performance is monitored and analyzed with ClimaCheck(CC) instrumentation. The average cooling capacity is calculated for four warm days by CC internal method and actual cooling energy produced is obtained by practically assumed COP of system with aid of MYCOM compressor software. The cooling capacity and heat loads on ice surface are compared and analyzed considering energy usage affecting parameters and weather parameters like temperature, wind speed, relative humidity and solar load. The convection and condensation are contributing 75%, radiation 18%, ice resurfacing 4% and ground and header heat gain 3% to total heat loads on ice sheet for whole season. The deviation between total cooling energy produced by refrigeration machine and total heat load energy is found 19% and 27% for four warm days and whole season 2010-2011.The deviation is due to overestimation of heat losses from compressor’s body, compressor’s on and off operations, overestimated radiation heat load due to unmeasured negative radiation and lack of actual ice resurfacing heat load evaluation. The developed model in MS Excel allows comparison of field climate data with SMHI model data, indoor and outdoor ice rinks in terms of predicted energy usage by refrigeration system and in total and acts as decision tool to choose for building an indoor/outdoor ice rink.
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