Energy Efficiency of Building Envelopes

2013 ◽  
Vol 855 ◽  
pp. 39-42 ◽  
Author(s):  
Richard Jedinák

Energy efficiency of buildings is one of the basic requirements of current architectural engineering. The new recast of the Energy Performance of Buildings Directive (EPBD) calls for all new buildings to be nearly zero energy buildings by the end of 2020. To achieve this target is quite challenging. Nowadays some of the buildings that are realized are reaching these objectives. The current market is able to offer a wide range of thermal systems and thermal insulation materials themselves and the right choice of thermal system or thermal insulation material is a difficult task. Considering the significant impact that energy consumption has, is particularly important to implement policies aimed at improving energy efficiency in buildings. Highly energy efficient buildings can either save primary energy or disseminate the use of the most suitable technologies to be used in new constructions. The building may be considered as an example to study and optimize the benefits of higher energy efficiency together with the use of renewable energy systems. This article is going to discuss the characteristics of these solutions, trends in their research and development and their conceptual bases.

2022 ◽  
Vol 906 ◽  
pp. 99-106
Author(s):  
Siranush Egnatosyan ◽  
David Hakobyan ◽  
Spartak Sargsyan

The use of thermal insulation materials to reduce the heating and cooling demand of the building in order to provide energy efficiency is the main solution. But there is a wide range of these products on the market and, therefore, the choice and application of these materials is a rather difficult task, since many factors must be taken into account, such as environmental safety, cost, durability, climatic conditions, application technology, etc. Basically, comfort microclimate systems are designed based on normative standards, where the thickness of the thermal insulation material is selected depending on the required heat transfer resistance. These values are calculated taking into account climate conditions, that is the duration of the heating period, as well as taking into account sanitary and hygienic requirements. This article discusses the thermal performance of building materials, and also provides a comparative analysis of the use of thermal insulation materials depending on climatic factors and on the system providing comfort microclimate. Based on the calculations by mathematical modeling and optimization, it is advisable to choose the thickness of the thermal insulation, taking into account the capital and operating costs of the comfort microclimate systems. Comparing the optimization data with the normative one, the energy efficiency of the building increases by 50-70% when applying the optimal thickness of the thermal insulation layer, and when the thermal insulation layer is increased, the thermal performance of the enclosing structures has improved by 30%, which contributes to energy saving.


2020 ◽  
Vol 12 (14) ◽  
pp. 5764
Author(s):  
Purvesh Bharadwaj ◽  
Ljubomir Jankovic

Traditionally, the uniform application of thermal insulation is practised within the built environment sector to achieve desired building regulation standards for energy efficiency. However, that approach does not follow the building heat loss field, and it is therefore poorly matched to the actual heat loss from the building, thus achieving sub-optimum energy performance. This research aims to visualise building heat loss field in three dimensions and to create self-organised thermal insulation patterns that are proportional in thickness to the intensity of heat loss. This is achieved using a 3D agent-based model, in which each agent that represents a miniature object of thermal insulation moves up the gradient of the heat loss representation and competes for its position with the neighbouring thermal insulation components, depending upon the gradient intensity. This creates a self-organised thermal insulation pattern through the competition between the thermal insulation components and through overcrowding in the areas with higher heat loss intensity. This helps to visualise the heat loss field and create a representation of thermal insulation that is ideally matched to it. The result is assessed for its energy performance using a conventional energy performance analysis. That analysis shows that this approach leads to reductions in energy consumption and carbon emissions in comparison with the conventional approach that uses the same amount of thermal insulation material. The overall result increases our understanding of 3D heat loss and introduces a new approach for designing building thermal insulation.


2021 ◽  
Vol 13 (13) ◽  
pp. 7359
Author(s):  
Sadaf Alam ◽  
Miimu Airaksinen ◽  
Risto Lahdelma

Key stakeholders in industry are highly responsible for achieving energy performance targets. Particularly, this paper assesses the attitudes, approaches, and experiences of Finnish construction professionals regarding energy-efficient buildings, or nZEBs. A three-tier investigation was conducted including surveys and expert interviews with several stakeholders. The structure of this approach was informed by preliminary data and information available on the Finnish construction sector. The questionnaire showed that the stakeholders ranked energy efficiency and embodied energy/carbon as very important. The survey highlighted that the importance of the embodied carbon CO2 in the materials is less important than the energy efficiency from many of the stakeholders’ points of view. “Energy efficiency” is very important for ESCOs, contractors, and facility managers followed by architects, HVAC engineers, and construction design engineers. Nevertheless, the opinions of architects ranked “embodied energy CO2” as the most important regarding nZEB. When it comes to the importance of “running time emissions” toward nZEB, contractors and ESCO companies ranked it as 1 for importance followed by property owners (78%) and tenants (75%). It is very fascinating to see from the survey that “running time carbon emissions” has been ranked 1 (very important) by all stakeholders. This study will enable construction industry stakeholders to make provisions for overcoming the barriers, gaps, and challenges identified in the practices of the nZEB projects. It will also inform the formulation of policies that drive retrofit uptake.


2019 ◽  
Vol 10 (2) ◽  
pp. 59-66
Author(s):  
E. A Biryuzova ◽  
A. S Glukhanov

Through pipelines of heat networks, due to their large length, a large amount of thermal energy is lost. Identification of technical solutions related to improving the energy efficiency of heating networks is an urgent task at present. The article is devoted to the consideration of options for laying pipelines of heat networks during design work. In the conducted studies, two main methods of underground laying of pipelines of heat networks with the choice of the most energy-efficient, with minimal losses of thermal energy are considered. Channel and channelless laying methods are investigated with the same design features and technological conditions of operation of pipelines of heat networks using the same thermal insulation material. For each option, the required thickness of the thermal insulation is determined by the normalized density of the heat flow, thermal calculations are performed to determine the heat loss and the value of the temperature fields generated around the operating pipelines of the heat networks. The obtained values of the thermal insulation thickness in the channel method of laying pipelines are 30-50 % lower than those in channelless laying. The heat loss values, according to the results of the heat calculation for the options under consideration, in the channel method of laying are reduced by 47-65 %. The temperature fields formed around the pipelines of thermal networks with channelless laying significantly exceed the natural value of the soil temperature at the depth of the pipeline. What has a great influence on the determination of the distance to adjacent pipelines and other utilities, laid underground, in the zone of the thermal network. A comparative analysis of the results obtained makes it possible to single out the choice of the method of laying the pipeline into a group of measures aimed at energy saving and increasing energy efficiency in heating systems.


2019 ◽  
Vol 111 ◽  
pp. 03037
Author(s):  
Merve Atmaca ◽  
Zerrin Yýlmaz

In Turkey, according to TUİK Sectoral Energy Consumption Statistics (2006), the hotel buildings with the highest share, constitute 35% of the total building energy consumption. Energy needs and consumption behaviours differ according to the typology of the building. Energy Performance of Buildings Directive (EPBD) has been adapted to the conditions of Turkey to increase energy and cost efficiency, to reduce the environmental and economic negative effects. The energy consumption and the global cost were investigated under different conditions in an existing hotel building. The paper is unique in its ability to deliver optimum solution through comparison by evaluating energy and cost efficiency at the same time considering sectoral, climatic, technological and economic national conditions when the literature research detailed in the present works about the problem is evaluated in detail. All findings have been compared simultaneously under different climate regions of seasonal and yearly working conditions of selected test hotel to obtain the energy and cost efficiency. Among the proposed improvement scenarios, the optimum scenario is determined in terms of cost and energy efficiency in S18 which has the highest energy efficiency. In this case, both insulation material type and thickness as well as glass type can be bent and through multiple measures can be achieved by 25.7% improvement for energy efficiency.


2015 ◽  
Vol 789-790 ◽  
pp. 1181-1184
Author(s):  
Michal Kraus ◽  
Kateřina Kubeková ◽  
Darja Kubečková

The main objective of the paper is to confirm or exclude a statistically significant impact of airtightness on the energy performance of buildings. Energy performance of buildings is characterized by a specific energy demand for heating and specific total primary energy. Airtightness is one of the key factors of energy efficient buildings. The quality of airtight building envelope except for low energy consumption also minimizes the risk of damage to the structure associated with the spread of the heat and water vapor in the structure.


2013 ◽  
Vol 639-640 ◽  
pp. 350-353 ◽  
Author(s):  
Xiao Hong Zheng ◽  
Zhu Li ◽  
Yuan Zhen Liu ◽  
Shang Song Qin

The durability of thermal insulation glazed hollow bead concrete, which is a kind of structure self-thermal insulation material produced in the background of building energy efficiency, has been systematically researched in order to make it with a good workability. Theoretical analysis and experimental study have been made from the raw materials and construction mixing proportion in the basis of the analysis to the influencing factors of its durability so as to can improve its durability.


Author(s):  
T. T. Chow ◽  
J. Ji ◽  
W. He

Photovoltaic-thermal (PV/T) systems integrate photovoltaic and solar thermal technologies into one single system with dual production of electricity and heat energy. A typical arrangement is the direct attachment of PV modules on to a solar thermal collector surface. For a given collector surface area, the overall system energy performance is expected higher than the conventional “side-by-side” PV and solar thermal systems. In the development of PV/T collector technology using water as the coolant, the most common design follows the sheet-and-tube thermal absorber concept. Fin performance of the thermal absorber has been identified as one important factor that affects much the overall energy performance of the collector. Accordingly, an aluminum-alloy flat-box type PV/T collector prototype was constructed and tested. Our test results indicate that a high combined thermal and electrical efficiency can be achieved. The primary-energy-saving efficiency for daily exposure approaches 65% at zero reduced temperature operation. With a simple and handy design, the product is considered to be very suitable for domestic application.


2014 ◽  
Vol 564 ◽  
pp. 315-320 ◽  
Author(s):  
Maatouk Khoukhi ◽  
Mahmoud Tahat

The impact of the thermal conductivity (k-value) change of polystyrene insulation material in building envelope due to changes in temperature on the thermal and energy performance of a typical residential building under hot climate is investigated. Indeed, the thermal and energy performance of buildings depends on the thermal characteristics of the building envelope, and particularly on the thermal resistance of the insulation material used. The thermal insulation material which is determined by its thermal conductivity, which describes the ability of heat to flow cross the material in presence of a gradient of temperature, is the main key to assess the performance of the thermal insulation material. When performing the energy analysis or calculating the cooling load for buildings, we use published values of thermal conductivity of insulation materials, which are normally evaluated at 24°C according to the ASTM standards. In reality, thermal insulation in building is exposed to significant and continuous temperature variations, due essentially to the change of outdoor air temperature and solar radiation. Many types of insulation materials are produced and used in Oman, but not enough information is available to evaluate their performance under the prevailing climatic condition. The main objective of this study is to investigate the relationship between the temperature and thermal conductivity of various densities of polystyrene, which is widely used as building insulation material in Oman. Moreover, the impact of thermal conductivity variation with temperature on the envelope-induced cooling load for a simple building model is discussed. This work will serve as a platform to investigate the effect of the operating temperature on thermal conductivity of other building material insulations, and leads to more accurate assessment of the thermal and energy performance of buildings in Oman.


Energies ◽  
2022 ◽  
Vol 15 (2) ◽  
pp. 532
Author(s):  
Carlos Herce ◽  
Chiara Martini ◽  
Marcello Salvio ◽  
Claudia Toro

Petroleum products account for the 32.3% of worldwide primary energy. There are more than 100 oil refineries in Europe that directly employ 119,000 people with a turnover of EUR 600 billion and around 1.2% to the total value added in manufacturing. Therefore, the petroleum refining sector is very important in the European economy, and its decarbonization is crucial in the energy transition. Refineries present a high degree of complexity and integration, and the continuous increase of their energy efficiency is a key topic for the sector. In this work an analysis of the energy efficiency in ten Italian refineries based on mandatory energy audits and public data is presented. The primary (0.0963 ± 0.0341 toe/t), thermal (3421.71 ± 1316.84 MJ/t), and electrical (68.20 ± 19.34 kWh/t) specific energy consumptions have been evaluated. Some insights about the impact of refined products mix (mainly driven by production of diesel fuel) and Nelson Complexity Index in energy consumption are presented. Lastly, an overview of energy performance improvement actions (EPIAs) information extracted from energy audits is presented. This work presents a first step for the benchmark of Italian refineries that should be subsequently improved.


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