scholarly journals Fachadas vidriadas: cálculo de transmitancia térmica

2021 ◽  
Vol 11 (1) ◽  
pp. 08-19
Author(s):  
Maureen de Gastines ◽  
◽  
Andrea Pattini

Glazing is one of the dominant features of modern and contemporary architecture. This envelope design may have a great impact on operational energy demand of buildings. In this work, glazed façade systems available in Argentina are analyzed, with the purpose of determining the associated thermal transmittance ranges, in terms of the profiles’ design, the type of glazing and the size of glass panes. First, by using bidimensional numerical calculation, the impact of several profile design parameters on thermal transmittance is studied, highlighting the relevance of glazing fixing methods, to then calculate the thermal transmittance of the entire facade. The results indicate that the thermal transmittance value of glazed facades, mainly depends on the transmittance of the glass used, and exceeds this by 24% on average.

2015 ◽  
Vol 16 (SE) ◽  
pp. 97-103
Author(s):  
Allah Bakhsh Kavoosi ◽  
Shahin Heidari ◽  
Hamed Mazaherian

Growth and development of technology caused enormous transformation and change in the world after Industrial Revolution. The contemporary human has prepared the platform for their realization in many activities that the humans were unable to do it in the past time and struck the dream of their realization in their mind so that today doing many of those activities have been apparently practical by human. This accelerating growth accompanied with consuming a lot of energy where with respect to restriction of the given existing resources, it created energy crises. On the other hand, along with growth in industry and requirement for manpower and immigration from village to city and basic architectural changes in houses, which have emerged due to change in social structure it has led to change in lifestyle and type and quantity of consuming energy in contemporary architecture. Inter alia, with increase in human’s capability, cooling and heating and acoustic and lighting technologies were also changed in architecture and using mechanical system was replaced by traditional systems. Application of modern systems, which resulted from growth of industry and development of technology and it unfortunately, caused further manipulation in nature and destruction of it by human in addition to improving capability and potential of human’s creativity. With respect to growth of population and further need for housing and tendency to the dependent heating and cooling systems to them in this article we may notice that the housing is assumed as the greatest consumer of energy to create balance among the exterior and interior spaces in line with creating welfare conditions for heating and cooling and lighting. The tables of energy demand prediction in Iran show that these costs and energy consumption will be dubbed with energy control smart management in architecture.


Author(s):  
Eur Ing A J Blokland ◽  
I P Barendregt ◽  
C J C M Posthumus

The Netherlands Ministry of Defence (MoD) has issued an Operational Energy Strategy (OES) with ambition targets for energy independence and improvement of energy efficiency during the life time of naval platforms. A target is given in 2030 of 20 % reduced dependence on fossil fuels and in 2050 of 70 % reduced dependence on fossil fuels, compared to 2010. More stringent environmental emission (NOx, CO2, etc.) requirements are to be expected as a result from IMO and (local) political regulations. In the last decades the power consumption on board of naval platforms increased substantially as well as the complexity of integrated energy systems. Market surveys shows that the evolution of commercial green technologies are promising but have to be demonstrated in the coming years on low power and energy levels. They will not be de-risked in depth or well proven to be successful in time to be selected for the Royal Netherlands Navy (RNLN) new naval projects (2019 – 2025). Furthermore, new technologies as energy resources and carriers (H2, LNG, methanol, power-to-liquid (PTL), etc.) or new system technologies (DC on high voltage level, fuel cell systems, waste energy recovery, etc.) require a new approach for integration aspects like hazard and safety cases and energy efficiency. This is because the energy demand on board of naval platforms in several military operational modes differ from the merchant and off-shore branch. In this paper an approach for an adaptable energy platform is described to design a new naval platform based on nowadays proven technology as fossil fuels that can be transformed during life time that can fulfill the expectations and requirements of the coming decades (non-fossil fuels, zero emission, improved energy efficiency). Aspects as a naval energy index as reference will be discussed as well as an evaluation of new technologies for new naval platform integration design parameters, such as power or energy demands, consequences of energy resources, energy control as well as build in ship construction safety measures.


2021 ◽  
Vol 13 (17) ◽  
pp. 9491
Author(s):  
Manuel Carpio ◽  
David Carrasco

The increase in energy consumption that occurs in the residential sector implies a higher consumption of natural resources and, therefore, an increase in pollution and a degradation of the ecosystem. An optimal use of materials in the thermal envelope, together with efficient measures in the passive architectural design process, translate into lower energy demands in residential buildings. The objective of this study is to analyse and compare, through simulating different models, the impact of the shape factor on energy demand and CO2 emissions depending on the type of construction solution used in the envelope in a cold oceanic climate in South Chile. Five models with different geometries were considered based on their relationship between exposed surface and volume. Additionally, three construction solutions were chosen so that their thermal transmittance gradually complied with the values required by thermal regulations according to the climatic zone considered. Other parameters were equally established for all simulations so that their comparison was objective. Ninety case studies were obtained. Research has shown that an appropriate design, considering a shape factor suitable below 0.767 for the type of cold oceanic climate, implies a decrease in energy demand, which increased when considering architectural designs in the envelope with high values of thermal resistance.


2020 ◽  
Vol 2020 ◽  
pp. 1-14
Author(s):  
Yongming He ◽  
Yuting Song ◽  
Yulong Pei ◽  
Bin Ran ◽  
Jia Kang

To improve driving safety on superhighways, longitudinal profile design parameters of a superhighway are calculated via force analysis while a car is driven on a slope. The calculations consider characteristics of drivers, cars, and roads. According to the vehicle type, design speed, and natural conditions, the maximum longitudinal slope of a superhighway is calculated and compared with those of an ordinary superhighway and high-speed railway. Based on analysis of the vehicle climbing performance, braking performance, and driver visual characteristics, the maximum and minimum slope lengths of a superhighway are calculated. By analyzing the elements of vertical curves, the minimum radius and minimum length of the vertical curves of a superhighway are calculated by considering factors such as mitigating the impact at the slope bottom, driving at night, and driving time along vertical curves. Analysis and calculation results show that when the maximum longitudinal slope is 2.50%, 2.25%, and 2.00%, the minimum slope length is 450 m, 400 m, and 350 m, respectively, and the minimum vertical curve length is 145 m, 130 m, and 115 m, respectively, and the superhighway travel requirements can be satisfied at speeds of 180 km/h, 160 km/h, and 140 km/h, respectively.


Energies ◽  
2020 ◽  
Vol 14 (1) ◽  
pp. 56
Author(s):  
Walery Jezierski ◽  
Beata Sadowska ◽  
Krzysztof Pawłowski

Various methods can be used to reduce energy consumption in buildings. One of them is the tightening of energy requirements, which, like other methods, cannot result in a worsening of the indoor environmental quality. The article presents a study on the impact of changes in the thermal insulation of the building envelope on the energy demand, heating costs, and emissions. Mathematical models of the dependence of the index of annual usable energy demand for heating (EUH) of a residential house on the thermal transmittance coefficients (Ui) of selected building elements were developed. Values of Ui were adopted at three levels, corresponding to the maximum required values—as approved in Polish law for the periods from 2014, 2017, and 2021. The analyses were conducted for the location of the building in three of the five climate zones of Poland. It turned out that the differences in the energy demand in various locations in Poland amount to 32.6%. The change in Ui in the analyzed period causes a decrease of EUH by almost 27%. Financial savings and a reduction of emissions strongly depend on the fuel used in the building. Increasing the level of thermal insulation of walls increases the perceptible temperature in rooms by 1.2–1.5%.


2020 ◽  
Vol 12 (11) ◽  
pp. 4636
Author(s):  
Lucía Pereira-Ruchansky ◽  
Alexis Pérez-Fargallo

Energy improvement studies normally use energy demand reduction as an indicator, disregarding dwellings that do not use air-conditioning systems or do so only under extreme weather conditions. They also do not quantify the impact of climate change on results. This research seeks to evaluate and prioritize energy improvements for existing Uruguayan dwellings, assessing energy demand and thermal comfort in both the current and future climate. A social dwelling was monitored and calibrated to assess energy efficiency measures simulating the current climate and for 2050 (IPCC Scenario A2). The results show that improvements must be linked to the use of air-conditioning in dwellings. When air-conditioning use is unknown, for example, in public policy, thermal transmittance in walls should be between 0.50–0.61 W/m2 K, in roofs between 0.32–0.47 W/m2 K, in openings 2.7 W/m2 K, airtightness under 5 ACH n50 and with solar protections. However, when the use under free running is certain, thermal transmittance in walls and roofs should be 0.85 W/m2 K with an airtightness of 9.2 ACH n50 and solar protection used to avoid overheating. The operational ventilation and solar protection parameters were helpful to guarantee comfort, underlining the need for their inclusion and to train those who use them.


Author(s):  
M. von der Thannen ◽  
S. Hoerbinger ◽  
C. Muellebner ◽  
H. Biber ◽  
H. P. Rauch

AbstractRecently, applications of soil and water bioengineering constructions using living plants and supplementary materials have become increasingly popular. Besides technical effects, soil and water bioengineering has the advantage of additionally taking into consideration ecological values and the values of landscape aesthetics. When implementing soil and water bioengineering structures, suitable plants must be selected, and the structures must be given a dimension taking into account potential impact loads. A consideration of energy flows and the potential negative impact of construction in terms of energy and greenhouse gas balance has been neglected until now. The current study closes this gap of knowledge by introducing a method for detecting the possible negative effects of installing soil and water bioengineering measures. For this purpose, an environmental life cycle assessment model has been applied. The impact categories global warming potential and cumulative energy demand are used in this paper to describe the type of impacts which a bioengineering construction site causes. Additionally, the water bioengineering measure is contrasted with a conventional civil engineering structure. The results determine that the bioengineering alternative performs slightly better, in terms of energy demand and global warming potential, than the conventional measure. The most relevant factor is shown to be the impact of the running machines at the water bioengineering construction site. Finally, an integral ecological assessment model for applications of soil and water bioengineering structures should point out the potential negative effects caused during installation and, furthermore, integrate the assessment of potential positive effects due to the development of living plants in the use stage of the structures.


2021 ◽  
Vol 13 (13) ◽  
pp. 7251
Author(s):  
Mushk Bughio ◽  
Muhammad Shoaib Khan ◽  
Waqas Ahmed Mahar ◽  
Thorsten Schuetze

Electric appliances for cooling and lighting are responsible for most of the increase in electricity consumption in Karachi, Pakistan. This study aims to investigate the impact of passive energy efficiency measures (PEEMs) on the potential reduction of indoor temperature and cooling energy demand of an architectural campus building (ACB) in Karachi, Pakistan. PEEMs focus on the building envelope’s design and construction, which is a key factor of influence on a building’s cooling energy demand. The existing architectural campus building was modeled using the building information modeling (BIM) software Autodesk Revit. Data related to the electricity consumption for cooling, building masses, occupancy conditions, utility bills, energy use intensity, as well as space types, were collected and analyzed to develop a virtual ACB model. The utility bill data were used to calibrate the DesignBuilder and EnergyPlus base case models of the existing ACB. The cooling energy demand was compared with different alternative building envelope compositions applied as PEEMs in the renovation of the existing exemplary ACB. Finally, cooling energy demand reduction potentials and the related potential electricity demand savings were determined. The quantification of the cooling energy demand facilitates the definition of the building’s electricity consumption benchmarks for cooling with specific technologies.


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