• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 5
  • 3
  • 1
  • 1
  • Tagged with
  • 10
  • 10
  • 10
  • 8
  • 7
  • 5
  • 5
  • 4
  • 3
  • 3
  • 3
  • 3
  • 3
  • 3
  • 3
  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Thermal Shape Factor : The impact of the building shape and thermal properties on the heating energy demand in Swedish climates

Olsson, Martin January 2016 (has links)
In the year 2006, the energy performance directive 2002/91/EG was passed by the European Union, according to this directive the Swedish building code was supplemented by a key measure of energy use intensity (EUI). The implemented EUI equals some energy use within a building divided by its floor area and must be calculated in new housing estate and shown when renting or selling housing property. In order to improve the EUI, energy efficiency refurbishments could be implemented. Building energy simulation tools enables a virtual view a building model and can estimate the energy use before implementing any refurbishments. They are a powerful resource when determine the impact of the refurbishment measure. In order to obtain a correct model which corresponds to the actual energy use, some adjustments of the model are often needed. This process refers to as calibration. The used EUI has been criticized and thus, the first objective in this work was to suggest an alternative key measure of a buildings performance. The results showed that the currently used EUI is disfavoring some districts in Sweden. New housing estate in the far north must take more refined actions in order to fulfill the regulation demand, given that the users are behaving identical regardless where the house is located. Further, the suggested measure is less sensitive to the users’ behavior than the presently used EUI. It also has a significance meaning in building design as it relating the building shape and thermal properties and stating that extreme building shapes must undergo a stricter thermal construction rather than buildings that are more compact. Thus, the suggested key measure also creates a communication link between architects and the consultant constructors. The second objective of this thesis has been to investigate a concept of calibration using the data normally provided by energy bills, i.e. some monthly aggregated data. A case study serves to answer this objective, by using the building energy simulation tool IDA ICE 4.7 and a building located in Umeå, Sweden. The findings showed that the used calibration approach yielded a model considered as calibrated in eleven of twelve months. Furthermore, the method gives a closer agreement to the actual heat demand rather than using templates and standardized values. The major explanation of the deviation was influence of the users, but also that the case study building burden with large heat losses by domestic hot water circulation and thus, more buildings should be subjected to this calibration approach.
2

Energy performance of multifamily buildings : building characteristic and user influence

Sjögren, Jan-Ulric January 2007 (has links)
<p>Today many professional property holders use different types of software for monthly energy analyses. The data is however often limited to energy and water use, that is paid for by the property holder. In year 2001, financed by the Swedish Energy Agency, the first steps were taken to create a national web based data base, eNyckeln. A property holder may then enter consumption data together with about 50 other building specific parameters to this data base in order to enable benchmarking and energy performance evaluations. Due to EU-regulations and the increasing awareness of energy and environmental issues there is a large interest in evaluating the energy performance and also to identify effective energy retrofits. The used energy performance indicator is still only the annual energy use for heating per square meter of area to let, kWh/m<sup>2</sup>,year, despite the fact that monthly data often are available. The main problem with this indicator, which is the stipulated measure, is that it reflects a lot of user influence and that only a part of the total energy use is considered. The main focus of this thesis is to explore the possibilities, based on the national data base, to extract additional energy information about multi family buildings (MFB) using monthly data in combination with different assumed consumption pattern but also to identify potential for energy savings. For the latter a multivariate method was used to identify relations between the energy use and building specific parameters. The analysis gave clear indications that the available area, the area to let, is not appropriate for normalization purposes since the remaining heated area can be significant. Due to this fact, the analysis was mainly limited to qualitative conclusions. As measure of the buildings energy characteristic, the total heat loss coefficient, <em>K<sub>tot</sub></em>,(W/ºK) is determined and the robustness for the estimate of<em> K<sub>tot</sub></em> to different assumptions of user behaviour is investigated. The result shows that the value of <em>K<sub>tot</sub></em> is fairly insensitive to different indoor temperature, use of domestic hot water and household electricity. With the addition of m<sup>2</sup> it can of course be used for benchmarking. Using the mentioned measure of the buildings energy characteristic for validating the energy performance has a clear advantage compared to the traditional kWh/m<sup>2</sup>, since the user behaviour is of minor importance. As a result of this an improved analysis of the energy performance will be obtained. A guarantee for new buildings energy performance based on this method is therefore a challenge for the building sector to develop.</p>
3

Thermal Performance of a Solarus CPC-Thermal Collector

Šumić, Mersiha January 2014 (has links)
The  aim  of  this  master  thesis  is  an  investigation  of  the  thermal  performance  of  a  thermal compound parabolic concentrating (CPC) collector from Solarus. The collector consists of two troughs with absorbers which are coated with different types of paint with  unknown  properties.  The  lower  and  upper  trough  of  the  collector  have  been  tested individually. In  order  to  accomplish  the  performance  of  the  two  collectors,  a  thorough  literature  study  in  the  fields  of  CPC  technology,  various  test  methods,  test  standards  for  solar thermal  collectors  as  well  as  the  latest  articles  relating  on  the  subject  were  carried  out. In addition, the set‐up of the thermal test rig was part of the thesis as well. The thermal  performance  was  tested  according  to  the  steady  state  test  method  as  described in the European standard 12975‐2. Furthermore, the thermal performance of  a  conventional  flat  plate  collector  was  carried  out  for  verification  of  the  test  method. The  CPC‐Thermal  collector  from  Solarus  was  tested  in  2013  and  the  results  showed  four  times  higher  values  of  the  heat  loss  coefficient  UL (8.4  W/m²K)  than  what  has been reported for a commercial collector from Solarus. This value was assumed to be too large and it was assumed that the large value was a result of the test method used that time. Therefore, another aim was the comparison of the results achieved in this work with the results from the tests performed in 2013. The results of the thermal performance showed that the optical efficiency of the lower trough of the CPC‐T collector is 77±5% and the corresponding heat loss coefficient UL 4.84±0.20  W/m²K.  The  upper  trough  achieved  an  optical  efficiency  of  75±6  %  and  a  heat loss coefficient UL of 6.45±0.27 W/m²K. The results of the heat loss coefficients  are  valid  for  temperature  intervals  between  20°C  and  80°C.  The  different  absorber paintings have a significant impact on the results, the lower trough performs overall better.  The  results  achieved  in  this  thesis  show  lower  heat  loss  coefficients UL and higher optical efficiencies compared to the results from 2013.
4

Energy performance of multifamily buildings : building characteristic and user influence

Sjögren, Jan-Ulric January 2007 (has links)
Today many professional property holders use different types of software for monthly energy analyses. The data is however often limited to energy and water use, that is paid for by the property holder. In year 2001, financed by the Swedish Energy Agency, the first steps were taken to create a national web based data base, eNyckeln. A property holder may then enter consumption data together with about 50 other building specific parameters to this data base in order to enable benchmarking and energy performance evaluations. Due to EU-regulations and the increasing awareness of energy and environmental issues there is a large interest in evaluating the energy performance and also to identify effective energy retrofits. The used energy performance indicator is still only the annual energy use for heating per square meter of area to let, kWh/m2,year, despite the fact that monthly data often are available. The main problem with this indicator, which is the stipulated measure, is that it reflects a lot of user influence and that only a part of the total energy use is considered. The main focus of this thesis is to explore the possibilities, based on the national data base, to extract additional energy information about multi family buildings (MFB) using monthly data in combination with different assumed consumption pattern but also to identify potential for energy savings. For the latter a multivariate method was used to identify relations between the energy use and building specific parameters. The analysis gave clear indications that the available area, the area to let, is not appropriate for normalization purposes since the remaining heated area can be significant. Due to this fact, the analysis was mainly limited to qualitative conclusions. As measure of the buildings energy characteristic, the total heat loss coefficient, Ktot,(W/ºK) is determined and the robustness for the estimate of Ktot to different assumptions of user behaviour is investigated. The result shows that the value of Ktot is fairly insensitive to different indoor temperature, use of domestic hot water and household electricity. With the addition of m2 it can of course be used for benchmarking. Using the mentioned measure of the buildings energy characteristic for validating the energy performance has a clear advantage compared to the traditional kWh/m2, since the user behaviour is of minor importance. As a result of this an improved analysis of the energy performance will be obtained. A guarantee for new buildings energy performance based on this method is therefore a challenge for the building sector to develop.
5

Simulação e avaliação de um sistema de aquecimento solar de água utilizando balanço energético / Simulation and evaluation of a system of solar water heating using energy balance

Medeiros, Maurício 17 February 2012 (has links)
Made available in DSpace on 2017-07-10T15:14:45Z (GMT). No. of bitstreams: 1 Mauricio Medeiros.pdf: 2573107 bytes, checksum: 1e5a17966417b43d576f37b4837c682b (MD5) Previous issue date: 2012-02-17 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / This work was developed at the State University of West of Paraná UNIOESTE, campus de Cascavel and was aimed at developing a computer program to simulate and scale, optimally, a system of solar water heating. To determine the efficiency parameters of the system were installed three solar collectors of 1.05 m2 each, brand Pro Sol, coupled to a thermal reservoir of 200 liters, containing electrical resistances auxiliary 2000 W. The system works by using thermosyphon, and was installed in a metal bracket fixed to the ground, oriented to the north at an angle of 35 degrees from the horizontal. We collected hourly data of solar radiation and water temperatures, and evaluated two scenarios. In the first scenario, it was considered system utilization auxiliary heating controlled by a thermostat, which linked and hang up the electrical resistances as the temperature of water in boiler oscillated around of temperature of consumption (40 º C). In the second scenario, it was considered the system to power auxiliary heating only in timetables of water consumption, when the water temperature in boiler was lower than the temperature of consumption. Coefficients were calculated heat loss in the solar collector and storage tank, the heat removal factor of solar collector and the overall efficiency of the heating system installed. These calculated parameters and other data collected were used in software developed for simulation and design in order to satisfactorily meet the needs of hot water consumption, and minimize the total installation costs and energy consumption. Finally, these system costs solar heating were compared to costs of an electric shower conventional. The results obtained were as follows: coefficient of heat loss in the solar collector (5,45 Wm-2ºC-1), coefficient of heat loss in the thermal reservoir (5,34 Wm-2ºC-1), removal factor heat of the solar collector (0.78) and overall system efficiency (31%). The times of return on capital invested in the solar heating system (compared to a conventional electric shower), for the two scenarios of use, were, respectively, 11.45 years and 7.81 years. / Este trabalho foi desenvolvido na Universidade Estadual do Oeste do Paraná UNIOESTE, campus de Cascavel, e teve por objetivo principal o desenvolvimento de um programa computacional para simular e dimensionar, de forma otimizada, um sistema de aquecimento solar de água. Para determinar os parâmetros de eficiência do sistema, foram instalados três coletores solares de 1,05 m2 cada, da marca Pro Sol, acoplados a um reservatório térmico de 200 litros, contendo resistências elétricas auxiliares de 2000 W. O sistema utilizado funciona por termossifão, e foi instalado em um suporte metálico fixado ao solo, com orientação para o norte, num ângulo de 35º em relação à horizontal. Foram coletados dados horários de radiação solar e temperaturas da água, e avaliados dois cenários. No primeiro cenário, considerou-se a utilização do sistema de aquecimento auxiliar controlado por um termostato, que ligava e desligava as resistências elétricas conforme a temperatura da água no boiler oscilava em torno da temperatura de consumo (40ºC). No segundo cenário, considerou-se o acionamento do sistema de aquecimento auxiliar somente nos horários de consumo de água, quando a temperatura da água no boiler estivesse menor que a temperatura de consumo. Foram calculados os coeficientes de perda de calor no coletor solar e no reservatório térmico, o fator de remoção de calor no coletor solar e a eficiência global do sistema de aquecimento instalado. Esses parâmetros calculados, e os demais dados coletados, foram utilizados no software desenvolvido para simulação e dimensionamento, de maneira a atender satisfatoriamente às necessidades de consumo de água quente, e minimizar os custos totais de instalação e consumo de energia elétrica. Por fim, esses custos do sistema de aquecimento solar foram comparados aos custos de um chuveiro elétrico convencional. Os resultados obtidos foram os seguintes: coeficiente de perda de calor no coletor solar (5,45 Wm-2ºC-1), coeficiente de perda de calor no reservatório térmico (5,34 Wm-2ºC-1), fator de emoção de calor do coletor solar (0,78) e eficiência global do sistema (31%). Os tempos de retorno do capital investido no sistema de aquecimento solar (em comparação a um chuveiro elétrico convencional), para os dois cenários de utilização, foram de, respectivamente, 11,38 anos e 5,73 anos.
6

A Statistical Approach to Estimate Thermal Performance and Energy Renovation of Multifamily Buildings : Case study on a Swedish city district

Eriksson, Martin January 2022 (has links)
Several climate and energy goals have been set in the European Union, one of them being to increase energy efficiency. In Sweden, a large potential for increased energy efficiency lies in the residential and service sectors, which account for about 40% of total energy use. A large share of buildings in Sweden were built in the Million Homes Program in the 1960s and ’70s. These buildings are now in need of renovation, which enables renovation with the ambition of reducing energy use.  In this thesis, the purpose is to develop an energy signature method, a bottom-up statistical method. This method has been validated using a building energy simulation software called IDA ICE, for two kinds of multifamily buildings from the Million Homes Program. The energy signature method has then been applied to a district located in Gävle, Sweden, containing more than 90 multifamily buildings with similar construction. In addition to characterizing current thermal performance of the buildings, the energy signature method is further developed so that potential for energy renovation of the district can be simulated. Simulated energy renovation is developed to comply with building energy use requirements, according to the most recent Swedish building regulations.  Both on building and district level, sensitivity analysis is performed. In both cases the energy signature method is insensitive to changes in internal heat gains and indoor temperature. To investigate the effects of simulated renovation on a local district heating system, results are visualized in a duration diagram, where energy use reduction in different load periods is displayed. Thus, it is demonstrated how the energy signature method can be used as a rapid way of simulating energy renovation on district level and with readily available data. / EU har beslutat om flera klimat- och energimål, bland annat att energi ska användas mer effektivt. I Sverige finns en stor potential för ökad energieffektivitet i bostads- och servicesektorn, som står för cirka 40 % av den totala energianvändningen. En stor av del Sveriges byggnadsbestånd består av miljonprogramsbyggnader från 1960- och 1970-talen. Dessa byggnader är i behov av renovering, vilket möjliggör ytterligare renovering med syfte att sänka energianvändningen. Syftet med denna studie är att utveckla en energisignaturmetod, en ”bottom-up” statistisk metod. Metoden har validerats med byggnadsenergisimuleringsprogrammet, IDA ICE, för två typer av flerbostadshus från miljonprogrammet. Energisignaturmetoden har sedan applicerats på ett distrikt i Gävle som innehåller fler än 90 flerbostadshus med liknande konstruktion. Förutom att karakterisera byggnadernas nuvarande termiska prestanda, vidareutvecklas energisignaturmetoden så att även energirenovering kan simuleras. Denna metod utvecklas för att uppfylla Boverkets krav på byggnaders energianvändning, enligt gällande svenska byggnadsreglerna.  Känslighetsanalys utförs både på byggnads- och distriktsnivå. I båda fallen visar sig energisignaturmetoden vara okänslig för förändringar i intern värmegenerering och inomhustemperatur. Effekterna av den simulerade renoveringen presenteras i ett varaktighetsdiagram, som visar de möjliga effekterna på ett lokalt fjärrvärmesystem. På detta sätt demonstreras hur energisignaturmetoden kan användas för att snabbt simulera energirenovering på distriktsnivå och med lättillgänglig data.
7

Energetická náročnost budovy s téměř nulovou spotřebou energie / The energy demand of buildings with almost zero energy consumption

Horáčková, Leona January 2020 (has links)
The master thesis is focused on rating of buildings with almost zero energy consumption. Theoretical part summarizes general requirements on buildings with almost zero energy consumption. It also discusses other categories of buildings on terms of energy demand and influences and factors affecting the energy performance of buildings. The calculating part comparing three different construction systems of designed family house by means of energy demand with energy assessment and energy performance certificate of buildings.
8

Posouzení energetické náročnosti objektu pro vzdělávání / Energy consumption and energy supply of educational building

Šperka, Radim January 2014 (has links)
This thesis deals with the processing of an energy audit of the selected building for daily education. The target of this thesis is an evaluation of the current situation of the building, it means the evaluation of the thermal-technical qualities and energy consuption. For the initial state new measures will be suggested to reduce the energy consuption. One of the measures will be a proposal for an alternative way of supplying of the thermal energy, using the thermal pump. These suggested saving measures will be evaluated, including basic economic analysis.
9

Skiljer sig energiberäkningarna i projekteringsstadiet från energiberäkningarna i relationshandlingarna?

Ingarsson, Ellen, Sköld, Ellen January 2022 (has links)
To reduce the emissions from energy use, high demands are set on new buildings. Studies have shown big differences between predicted and actual energy performance. This gap makes it more difficult to reduce the energy use in buildings. The aim of this study is to discover if deviations occur before the building is put into use, and if it does, discuss the reasons for that.  In this study, energy performance for 20 multi-family houses have been compared between the early design stage and the production stage. The result of this study is that there are no major differences in energy use between the different documents. On the other hand, there are big differences in some of the parameters that the energy use is dependent on. The reasons of this are discussed later in this thesis. None of the investigated buildings had the same value of energy performance in the production stage as in the early stage. The parameter that has shown the greatest difference is space heating and hot water recirculation. The biggest correlation was found between the energy required by the fans and the buildings total energy use.
10

Studie snížení energetické náročnosti bytového domu / Study of energy consumption reduction of block of flats

Svoboda, Lukáš January 2014 (has links)
The goal of the thesis is firstly to get all the information about the initial state of solved block of flats, which is located on the street Merhautova 76/954 in Brno – Černá pole, in terms of constructions, energy consumption and initial state of heating system. In the second part of the thesis, where are discussed the possibilities of reduction of energy consumption, variant drafts of reduction of energy consumption and their financial costs and the choice of optimal variant. Third part deals with assement of solved block of flats in terms of sustainable built environment by using tool to rate buildings in terms of sustainable built environment - SBToolCZ, evaluation of possibility to use renewables. In the end are written summaries and recommendations.

Page generated in 0.1332 seconds