scholarly journals Seismic and Energy Retrofit of Apartment Buildings through Autoclaved Aerated Concrete (AAC) Blocks Infill Walls

2019 ◽  
Vol 11 (14) ◽  
pp. 3939 ◽  
Author(s):  
Antonio Artino ◽  
Gianpiero Evola ◽  
Giuseppe Margani ◽  
Edoardo Marino

All around the world, a huge amount of buildings have been built before the enforcement of specific codes for seismic resistance and energy efficiency. Particularly in Italy, over 74% of residential buildings were constructed before 1980, when only 25% of the territory was classified as seismic, and nearly 86% were built before 1991, when the first restrictive regulation on energy efficiency was issued. This means that most buildings need both seismic and energy renovation actions to improve their sustainability level. The proposed combined retrofit strategy for reinforced concrete framed buildings is based on the replacement of the external layer of double-leaf infill walls, made of hollow bricks, with high-performing AAC blocks: this solution can be implemented by operating mainly from the outside of the building, thus reducing occupants’ disruption during retrofitting. The generally neglected structural contribution of masonry infill panels is here considered using a recently developed macro-element modeling approach. The results suggest that, from a structural viewpoint, the proposed intervention involves the highest improvement at the damage limitation limit state, while lower upgrades are recorded at life safety limit state and near-collapse limit state. In regards to the energy issues, the energy demand can be reduced by 10% and 4% for heating and cooling, respectively, just by replacing the outer layer of blocks; further savings can be achieved through the application of a supplementary insulation layer.

Energies ◽  
2020 ◽  
Vol 13 (22) ◽  
pp. 5979
Author(s):  
Ikram Merini ◽  
Angel Molina-García ◽  
M. Socorro García-Cascales ◽  
Mustapha Mahdaoui ◽  
Mohamed Ahachad

The trend in energy consumption, with a particular focus on heating and cooling demand, is an issue that is relevant to the promotion of new energy policies and more efficient energy systems. Moreover, heating and cooling energy demand is expected to rise in the next several decades, mainly due to climate change as well as increasing incomes in developing countries. In this context, the building sector is currently a relevant energy-intensive economic sector in Morocco; it accounts for 33% of the country’s total energy demand (as the sector with the second highest energy demand, after the transport sector), with the residential sector accounting for 25% and the tertiary sector accounting for 8%. Aiming to reduce energy dependence and promote sustainable development, the Moroccan government recently issued a comprehensive plan to increase the share of renewables and improve energy efficiency. This strategy includes novel thermal building regulations promoted by the Moroccan Agency for Energy Efficiency. This paper analyzes the thermal behavior and heating-cooling energy demand of a residential building located in Tangier (Morocco) as a case example, based on the country’s new thermal regulations and considering specific climatological conditions. A comparison with common Moroccan residential buildings as well as with those in nearby countries with similar meteorological conditions but significant differences in terms of energy demand regulation and requirements, such as Spain, is also included. Simulations were carried out using the DesingBuilder and EnergyPlus Software packages. According to the results, the last building thermal regulation requirements in Morocco need to be revised and extended in order to achieve the energy efficiency objectives established by the Moroccan government for 2030.


Atmosphere ◽  
2021 ◽  
Vol 12 (6) ◽  
pp. 715
Author(s):  
Cristina Andrade ◽  
Sandra Mourato ◽  
João Ramos

Climate change is expected to influence cooling and heating energy demand of residential buildings and affect overall thermal comfort. Towards this end, the heating (HDD) and cooling (CDD) degree-days along with HDD + CDD were computed from an ensemble of seven high-resolution bias-corrected simulations attained from EURO-CORDEX under two Representative Concentration Pathways (RCP4.5 and RCP8.5). These three indicators were analyzed for 1971–2000 (from E-OBS) and 2011–2040, and 2041–2070, under both RCPs. Results predict a decrease in HDDs most significant under RCP8.5. Conversely, it is projected an increase of CDD values for both scenarios. The decrease in HDDs is projected to be higher than the increase in CDDs hinting to an increase in the energy demand to cool internal environments in Portugal. Statistically significant linear CDD trends were only found for 2041–2070 under RCP4.5. Towards 2070, higher(lower) CDD (HDD and HDD + CDD) anomaly amplitudes are depicted, mainly under RCP8.5. Within the five NUTS II


Author(s):  
Hugo Hens

Since the 1990s, the successive EU directives and related national or regional legislations require new construction and retrofits to be as much as possible energy-efficient. Several measures that should stepwise minimize the primary energy use for heating and cooling have become mandated as requirement. However, in reality, related predicted savings are not seen in practice. Two effects are responsible for that. The first one refers to dweller habits, which are more energy-conserving than the calculation tools presume. In fact, while in non-energy-efficient ones, habits on average result in up to a 50% lower end energy use for heating than predicted. That percentage drops to zero or it even turns negative in extremely energy-efficient residences. The second effect refers to problems with low-voltage distribution grids not designed to transport the peaks in electricity whensunny in summer. Through that, a part of converters has to be uncoupled now and then, which means less renewable electricity. This is illustrated by examples that in theory should be net-zero buildings due to the measures applied and the presence of enough photovoltaic cells (PV) on each roof. We can conclude that mandating extreme energy efficiency far beyond the present total optimum value for residential buildings looks questionable as a policy. However, despite that, governments and administrations still seem to require even more extreme measurements regarding energy efficiency.


Energies ◽  
2020 ◽  
Vol 13 (6) ◽  
pp. 1309 ◽  
Author(s):  
Tomasz Szul ◽  
Stanisław Kokoszka

In many regions, the heat used for space heating is a basic item in the energy balance of a building and significantly affects its operating costs. The accuracy of the assessment of heat consumption in an existing building and the determination of the main components of heat loss depends to a large extent on whether the energy efficiency improvement targets set in the thermal upgrading project are achieved. A frequent problem in the case of energy calculations is the lack of complete architectural and construction documentation of the analyzed objects. Therefore, there is a need to search for methods that will be suitable for a quick technical analysis of measures taken to improve energy efficiency in existing buildings. These methods should have satisfactory results in predicting energy consumption where the input is limited, inaccurate, or uncertain. Therefore, the aim of this work was to test the usefulness of a model based on Rough Set Theory (RST) for estimating the thermal energy consumption of buildings undergoing an energy renovation. The research was carried out on a group of 109 thermally improved residential buildings, for which energy performance was based on actual energy consumption before and after thermal modernization. Specific sets of important variables characterizing the examined buildings were distinguished. The groups of variables were used to estimate energy consumption in such a way as to obtain a compromise between the effort of obtaining them and the quality of the forecast. This has allowed the construction of a prediction model that allows the use of a fast, relatively simple procedure to estimate the final energy demand rate for heating buildings.


Energies ◽  
2019 ◽  
Vol 12 (13) ◽  
pp. 2496 ◽  
Author(s):  
Laura Carnieletto ◽  
Borja Badenes ◽  
Marco Belliardi ◽  
Adriana Bernardi ◽  
Samantha Graci ◽  
...  

The design of ground source heat pumps is a fundamental step to ensure the high energy efficiency of heat pump systems throughout their operating years. To enhance the diffusion of ground source heat pump systems, two different tools are developed in the H2020 research project named, “Cheap GSHPs”: A design tool and a decision support system. In both cases, the energy demand of the buildings may not be calculated by the user. The main input data, to evaluate the size of the borehole heat exchangers, is the building energy demand. This paper presents a methodology to correlate energy demand, building typologies, and climatic conditions for different types of residential buildings. Rather than envelope properties, three insulation levels have been considered in different climatic conditions to set up a database of energy profiles. Analyzing European climatic test reference years, 23 locations have been considered. For each location, the overall energy and the mean hourly monthly energy profiles for heating and cooling have been calculated. Pre-calculated profiles are needed to size generation systems and, in particular, ground source heat pumps. For this reason, correlations based on the degree days for heating and cooling demand have been found in order to generalize the results for different buildings. These correlations depend on the Köppen–Geiger climate scale.


2019 ◽  
Vol 23 (3 Part B) ◽  
pp. 2071-2084 ◽  
Author(s):  
Norbert Harmathy ◽  
Danijela Urbancl ◽  
Darko Goricanec ◽  
Zoltán Magyar

The research elaborates various solutions using detailed economic evaluation and energy efficiency calculation and simulation technology for formulating applicable, energy and cost-efficient retrofit solutions of single-family residential buildings located in temperate climate areas. Primarily the annual energy demand for a reference existing single-family residential building was determined. The economic analysis was performed for six formulated refurbishment scenarios in order to determine which of the scenarios will demonstrate optimal performance both in energy and cost efficiency. A feasibility study was performed for the most efficient scenario, which included an economic evaluation of low temperature radiant heating systems were three energy suppliers (oil, natural gas and electricity for air to water heat pump) were compared. According to financial analyses the optimal scenario includes the replacement of windows, installation of 15 cm expanded polystyrene thermal insulation, low temperature radiant floor heating, with a payback period of ten years.


Author(s):  
Diego Da Silva de Souza ◽  
Paulo De Souza Silva ◽  
David Barbosa de Alencar

The general objective of this article was to promote through bibliographic studies the two types of lamps, in addition to the comparative analysis of compact fluorescent lamps versus LED lamps: an economy factor. The specific objectives were: - to explain the conceptual precepts on: lighting engineering, definitions, characteristics, invention, operation, defect, quality and the environments used and the NBRs regulations; - address the economic impact generated by the choice of LED lamps and compact fluorescent lamps; - emphasize on an economic feasibility study on the use of LED lamps and compact fluorescent lamps. The justification of the study is related, in the promotion regarding the use of LED lamps and compact fluorescents, in the factor that generates savings. Since the areas related to artificial lighting are responsible for a significant portion of energy demand, both on a large scale - such as lighting for public roads or industrial buildings - and on smaller scales - in commercial and residential buildings. Therefore, its promotion is crucial in the context of economic viability. The lamps provide the luminous energy, through which a better luminous efficiency is obtained. Currently, there are several types of lamps available, different in several aspects: luminous intensity, reproduction colors, energy efficiency, physical composition, method for emitting light, specific purposes, prices, among others. It is worth mentioning that the lamps differ from each other not only by the different luminous fluxes that they radiate, but also by the different powers they consume. In order to compare them, it is necessary to know how many lumens are generated per absorbed watt. This greatness is called energy efficiency. Thus, the proposal of a study was evidenced, in order to promote these luminous resources, in addition to emphasizing their economic viability.


2018 ◽  
Vol 3 (10) ◽  
pp. 191-202
Author(s):  
Mohd Najib Mohd Salleh ◽  
Mohd Zin Kandar ◽  
Siti Rasidah Md Sakip

Energy demand in buildings can reduce by improving energy efficiency. MS1525 has recommended that energy efficiency for Non-Residential Buildings in Malaysia to be not more than 135kWh/m²/year. A school building is a non-residential building and has major social responsibilities. Based on the theory of building energy-efficiency, energy efficiency can be achieved through three main factors: a) design of buildings; b) design of services; and c) user behavior. This study aims to investigate the user perceptions in High-Performance Schools. Keywords: User perception; building energy index; building energy efficiency; school building. eISSN 2514-7528 © 2018. The Authors. Published for AMER ABRA cE-Bs by e-International Publishing House, Ltd., UK. This is an open-access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/). Peer–review under responsibility of AMER (Association of Malaysian Environment-Behaviour Researchers), ABRA (Association of Behavioural Researchers on Asians) and cE-Bs (Centre for Environment-Behaviour Studies), Faculty of Architecture, Planning & Surveying, Universiti Teknologi MARA, Malaysia. DOI:https://doi.org/10.21834/jabs.v3i10.318  


Author(s):  
Robert Staiger

The chapter deals with the green energetic consideration of today's building envelopes for residential and non-residential buildings. It investigates the energetic effects the envelopes have on energy efficiency, energy consumption, material use, sustainable use of resources, lifetime considerations, economic and ecological impact. Today's it is estimated that approximately 30% of the annual primary energy demand for residential and non-residential buildings is needed. Energy resources for heat, electricity, air conditioning and cooling purposes, fossil fuels in form of gas and liquid are predominantly used.


2020 ◽  
Vol 12 (2) ◽  
pp. 25-61
Author(s):  
Simon Bawakyillenuo ◽  
Innocent Sefadzi Komla Agbelie

The challenge of reducing carbon emissions for the purpose of climate change mitigation requires both supply-side and demand-side energy efficiency measures. On the demand side, buildings worldwide account for about 30-40% of the total energy demand, thereby forming the largest sectoral consumer of electricity. Hence, the building sector offers a great opportunity for energy conservation and efficiency drives if certain behavioural patterns were to change. An important element of the building, which often influences energy consumption, is the design of the window. This paper investigates the economic, energy efficiency and sociological dimensions of the shift from traditional window designs to alternative ones in Ghana. Through quantitative and qualitative analyses of the data gathered for the 2014 Energy Surveys in the Ga East and Awutu Senya East Municipalities in Ghana, most homeowners use new window designs predominantly for aesthetic reasons. While more wooden and louvre blades windows users depend heavily on natural ventilation systems, glazed windows users depend mostly on fans and air conditioners. Consequently, glazed windows users spend more money on electricity compared to users of other window types. These findings manifest the energy inefficiency of most recent architectural designs in Ghana and, therefore call for appropriate policy interventions.


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