scholarly journals Life Cycle Cost Optimization of Residential Buildings in Bulgaria: a Case Study of the Building Envelope

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Nadezhda Doseva ◽  
Daniela Chakyrova
Keyword(s):  
Life Cycle ◽  
Energy Consumption ◽  
Life Cycle Cost ◽  
Residential Buildings ◽  
Cost Optimization ◽  
Optimization Procedure ◽  
Energy Performance ◽  
Legal Framework ◽  
Optimization Criterion ◽  
Building Envelope

Abstract Around 60 % of residential buildings in Bulgaria are constructed before the Nineties of the last century, i.e. they have been in use for more than 30 years. Furthermore, the final energy consumption of Bulgarian residential buildings is the highest in Europe. This raises the question of the improvement of the energy performance of existing residential buildings. The current study is intended to assess the influence of the heat transmittance coefficient of the external building envelop elements on the annual energy consumption for heating and cooling and finding its optimal value. Life-cycle cost (LCC) as the optimization criterion is using. The optimization procedure is conducted for the climatic and economic conditions in Bulgaria and taking into account the existing legal framework. The minimum of the building life cycle costs is determined by using a genetic algorithm.

scholarly journals The The Effects of Structural Lightweight Concrete on Energy Performance and Life Cycle Cost in Residential Buildings

2021 ◽  
Author(s):  
Safa Nayır ◽  
Ümit Bahadır ◽  
Şakir Erdoğdu ◽  
Vedat Toğan
Keyword(s):  
Thermal Conductivity ◽  
Energy Efficiency ◽  
Life Cycle ◽  
Energy Consumption ◽  
Life Cycle Cost ◽  
Lightweight Concrete ◽  
Residential Buildings ◽  
Energy Performance ◽  
Building Envelope ◽  
Life Cycle Costs

Energy efficiency in the construction industry is crucial to reducing increased energy consumption. A significant portion of the energy is consumed in residential buildings. Thermal properties of the materials used in the building envelope can reduce the energy consumed in the buildings and thus contribute to the building economy. For this purpose, in the study, structural lightweight concretes (SLWC) with a lower thermal conductivity than normal weight concrete (NWC) were produced and energy efficiency and life cycle costs were compared between these concretes on a 1 + 1 reference flat. The compressive strength, unit weights and thermal conductivity coefficients of SLWCs and NWC were determined experimentally. Heating and cooling energy consumption and life cycle costs for the flat were calculated using the DesignBuilder simulation program according to the different concrete types produced. The results indicate that the thermal conductivity coefficients of all SLWCs produced were about 37–45 % lower than those of NWC. All mixes of the SLWCs provided energy saving by about 18–25 % compared to the NWC and two SLWCs reduced the life cycle cost by 4 %. In addition, the results showed that the best SLWC about energy was not the best SLWC about life cycle cost.

scholarly journals Application of Life Cycle Energy Assessment in Residential Buildings: A Critical Review of Recent Trends

2020 ◽  
Vol 12 (1) ◽  
pp. 351 ◽  
Author(s):  
Hossein Omrany ◽  
Veronica Soebarto ◽  
Ehsan Sharifi ◽  
Ali Soltani
Keyword(s):  
Life Cycle ◽  
Energy Consumption ◽  
Energy Use ◽  
Residential Buildings ◽  
Current Trend ◽  
Energy Performance ◽  
Embodied Energy ◽  
System Boundary ◽  
Energy Assessment ◽  
Boundary Definition

Residential buildings are responsible for a considerable portion of energy consumption and greenhouse gas emissions worldwide. Correspondingly, many attempts have been made across the world to minimize energy consumption in this sector via regulations and building codes. The focus of these regulations has mainly been on reducing operational energy use, whereas the impacts of buildings’ embodied energy are frequently excluded. In recent years, there has been a growing interest in analyzing the energy performance of buildings via a life cycle energy assessment (LCEA) approach. The increasing amount of research has however caused the issue of a variation in results presented by LCEA studies, in which apparently similar case studies exhibited different results. This paper aims to identify the main sources of variation in LCEA studies by critically analyzing 26 studies representing 86 cases in 12 countries. The findings indicate that the current trend of LCEA application in residential buildings suffers from significant inaccuracy accruing from incomplete definitions of the system boundary, in tandem with the lack of consensus on measurements of operational and embodied energies. The findings call for a comprehensive framework through which system boundary definition for calculations of embodied and operational energies can be standardized.

scholarly journals Retrofitting a Building’s Envelope: Sustainability Performance of ETICS with ICB or EPS

2019 ◽  
Vol 9 (7) ◽  
pp. 1285 ◽  
Author(s):  
José D. Silvestre ◽  
André M. P. Castelo ◽  
José J. B. C. Silva ◽  
Jorge M. C. L. de Brito ◽  
Manuel D. Pinheiro
Keyword(s):  
Life Cycle ◽  
Energy Consumption ◽  
Thermal Insulation ◽  
Carbon Footprint ◽  
Energy Performance ◽  
Building Envelope ◽  
Expanded Polystyrene ◽  
Insulation Material ◽  
Economic Dimension ◽  
Heating And Cooling

This paper analyses the environmental, energy, and economic performances of the External Thermal Insulation Composite System (ETICS) using agglomerated insulation cork board (ICB) or expanded polystyrene (EPS) as insulation material applied in the energetic renovation of the building envelope during a 50-year study period. A comparison between ETICS using ICB and EPS, for the same time horizon, is also presented. The environmental balance is based on “Cradle to Cradle” (C2C) Life Cycle Assessment (LCA), focusing on the carbon footprint and consumption of nonrenewable primary energy (PE-NRe). The characteristics of these products in terms of thermal insulation, the increased energy performance provided by their installation for retrofit of the buildings’ envelope, and the resulting energy savings are considered in the energy balance. The estimation of the C2C carbon and PE-NRe saved is considered in the final balance between the energy and environmental performances. ETICS with ICB is environmentally advantageous both in terms of carbon footprint and of PE-NRe. In fact, the production stage of ICB is less polluting, while EPS requires lower energy consumption to fulfil the heating and cooling needs of a flat, due to its lower U-Value, and its lower acquisition cost results in a lower C2C cost. Comparing both ETICS’ alternatives with reference solutions, it was found that the latter only perform better in the economic dimension, and only for an energy consumption to fulfil less than 25% of the heating and cooling needs. This paper represents an advance to the current state-of-the-art by including all the life-cycle stages and dimensions of the LCA in the analysis of solutions for energy renovation of building envelopes.

scholarly journals Upgrading the Smartness of Retrofitting Packages towards Energy-Efficient Residential Buildings in Cold Climate Countries: Two Case Studies

Buildings ◽  
2020 ◽  
Vol 10 (11) ◽  
pp. 200 ◽  
Author(s):  
Laurina C. Felius ◽  
Mohamed Hamdy ◽  
Fredrik Dessen ◽  
Bozena Dorota Hrynyszyn
Keyword(s):  
Thermal Comfort ◽  
Life Cycle Cost ◽  
Energy Savings ◽  
Residential Buildings ◽  
Cost Effective ◽  
Energy Performance ◽  
Building Envelope ◽  
Heat Losses ◽  
Cold Climate ◽  
The Impact

Improving the energy efficiency of existing buildings by implementing building automation control strategies (BACS) besides building envelope and energy system retrofitting has been recommended by the Energy Performance of Buildings Directive (EPBD) 2018. This paper investigated this recommendation by conducting a simulation-based optimization to explore cost-effective retrofitting combinations of building envelope, energy systems and BACS measures in-line with automation standard EN 15232. Two cases (i.e., a typical single-family house and apartment block) were modeled and simulated using IDA Indoor Climate and Energy (IDA-ICE). The built-in optimization tool, GenOpt, was used to minimize energy consumption as the single objective function. The associated difference in life cycle cost, compared to the reference design, was calculated for each optimization iteration. Thermal comfort of the optimized solutions was assessed to verify the thermal comfort acceptability. Installing an air source heat pump had a greater energy-saving potential than reducing heat losses through the building envelope. Implementing BACS achieved cost-effective energy savings up to 24%. Energy savings up to 57% were estimated when BACS was combined with the other retrofitting measures. Particularly for compact buildings, where the potential of reducing heat losses through the envelope is limited, the impact of BACS increased. BACS also improved the thermal comfort.

scholarly journals Evaluating the potential energy savings of residential buildings and utilizing solar energy in the middle region of Saudi Arabia – Case study

2020 ◽  
pp. 014459872097514
Author(s):  
AbdulRahman S Almushaikah ◽  
Radwan A Almasri
Keyword(s):  
Energy Efficiency ◽  
Saudi Arabia ◽  
Energy Consumption ◽  
Solar Energy ◽  
Residential Buildings ◽  
Energy Performance ◽  
High Energy ◽  
Building Envelope ◽  
Economic Feasibility ◽  
Middle Region

Lately, with the growth in energy consumption worldwide to support global efforts to improve the climate, developing nations have to take significant measures. Kingdom of Saudi Arabia (KSA) implemented meaningful policy actions towards promoting energy efficiency (EE) in several sectors, especially in the building sector, to be more sustainable. In this paper, various EE measures and solar energy prospects are investigated for the residential sector, in two locations in the middle region of the KSA. An energy performance analysis of pre-existing residential buildings with an overall design is performed using simulation programs. However, installing EE measures in the building envelope is important to achieve an efficient sector regarding its energy consumption. The findings showed that applying EE measures for the building envelope, walls, roof, and windows should be considered first that makes the energy conservation possible. In Riyadh, EE measures are responsible for reducing energy consumption by 27% for walls, 14% for roof, and 6% for window, and by 29%, 13%, and 6% for walls, roof, and windows, respectively, for Qassim. However, the most impactful EE solution was selecting a heating, ventilation, and air conditioning (HVAC) system with a high energy efficiency rate (EER), which can minimize the energy consumption by 33% and 32% for Riyadh and Qassim, respectively. The study's feasibility showed that the number of years needed to offset the initial investment for a proposed roof PV system exceeds the project's life, if the energy produced is exported to the grid at the official export tariff of 0.019 $/kWh. However, the simple payback time was 13.42 years if the energy produced is exported to the grid at a rate of 0.048 $/kWh, reflecting the project's economic feasibility.

scholarly journals Energy Performance Analysis of Building Envelopes

2021 ◽  
Vol 11 (3) ◽  
pp. 196-206
Author(s):  
Ibrahim Motawa ◽  
Asser Elsheikh ◽  
Esraa Diab
Keyword(s):  
Life Cycle ◽  
Energy Consumption ◽  
Life Cycle Cost ◽  
Energy Performance ◽  
Building Envelopes ◽  
Heating And Cooling ◽  
Main Challenge ◽  
Sustainable Materials ◽  
High Level ◽  
Total Life

Abstract The building sector has a high level of energy consumption caused mainly by the buildings heating and cooling energy demands to satisfy indoor comfort requirements. Reducing both the amount of energy consumed and the life cycle cost is a main challenge for the construction of buildings. It is evident that sustainable materials have low environmental impacts and need low consumption of energetic resources in addition to their durability and recyclability. Therefore, this research aims to test different sustainable materials available in Egypt for the construction of building envelopes that include local stones “Marble and Limestone” and insulation materials “Polyurethane- expanded and Extruded polystyrene (XPS) foam” in order to achieve savings in energy and total life cycle cost. The simulation tests were conducted through Design Builder software. The results aim to provide solutions for building designers to achieve energy-efficiency and costeffective design. The proposed alternatives showed a significant reduction in energy consumption by up to 62% and the total life cycle costs significantly reduced by up to 45.8%.

Assessment of the Life Cycle Energy Efficiency of a Primary School Building in Turkey

2019 ◽  
Vol 887 ◽  
pp. 335-343
Author(s):  
Nazanin Moazzen ◽  
Mustafa Erkan Karaguler ◽  
Touraj Ashrafian
Keyword(s):  
Energy Efficiency ◽  
Life Cycle ◽  
Energy Consumption ◽  
Energy Demand ◽  
Energy Use ◽  
Human Life ◽  
Energy Performance ◽  
Building Envelope ◽  
Embodied Energy

Energy efficiency has become a crucial part of human life, which has an adverse impact on the social and economic development of any country. In Turkey, it is a critical issue especially in the construction sector due to increase in the dependency on the fuel demands. The energy consumption, which is used during the life cycle of a building, is a huge amount affected by the energy demand for material and building construction, HVAC and lighting systems, maintenance, equipment, and demolition. In general, the Life Cycle Energy (LCE) needs of the building can be summarised as the operational and embodied energy together with the energy use for demolition and recycling processes.Besides, schools alone are responsible for about 15% of the total energy consumption of the commercial building sector. To reduce the energy use and CO2 emission, the operational and embodied energy of the buildings must be minimised. Overall, it seems that choosing proper architectural measures for the envelope and using low emitting material can be a logical step for reducing operational and embodied energy consumptions.This paper is concentrated on the operating and embodied energy consumptions resulting from the application of different architectural measures through the building envelope. It proposes an educational building with low CO2 emission and proper energy performance in Turkey. To illustrate the method of the approach, this contribution illustrates a case study, which was performed on a representative schoold building in Istanbul, Turkey. Energy used for HVAC and lighting in the operating phase and the energy used for the manufacture of the materials are the most significant parts of embodied energy in the LCE analyses. This case study building’s primary energy consumption was calculated with the help of dynamic simulation tools, EnergyPlus and DesignBuilder. Then, different architectural energy efficiency measures were applied to the envelope of the case study building. Then, the influence of proposed actions on LCE consumption and Life Cycle CO2 (LCCO2) emissions were assessed according to the Life Cycle Assessment (LCA) method.

scholarly journals Analysis of the Effects of Strengthening Building Energy Policy on Multifamily Residential Buildings in South Korea

2020 ◽  
Vol 12 (9) ◽  
pp. 3566
Author(s):  
Byung Chang Kwag ◽  
Sanghee Han ◽  
Gil Tae Kim ◽  
Beobjeon Kim ◽  
Jong Yeob Kim
Keyword(s):  
Energy Consumption ◽  
South Korea ◽  
Energy Policy ◽  
Energy Demand ◽  
Residential Buildings ◽  
Building Energy ◽  
Energy Performance ◽  
Primary Energy ◽  
Building Envelope ◽  
Primary Energy Consumption

The purposes of this study were to overview the building-energy policy and regulations in South Korea to achieve energy-efficient multifamily residential buildings and analyze the effects of strengthening the building design requirements on their energy performances. The building energy demand intensity showed a linear relationship with the area-weighted average U-values of the building envelope. However, improving the thermal properties of the building envelope was limited to reducing the building-energy demand intensity. In this study, the effects of various energy conservation measures (ECMs) on the building-energy performance were compared. Among the various ECMs, improving the boiler efficiency was found to be the most efficient measure for reducing the building-energy consumption in comparison to other ECMs, whereas the building envelope showed the least impact, because the current U-values are low. However, in terms of the primary energy consumption, the most efficient ECM was the lighting power density because of the different energy sources used by various ECMs and the different conversion factors used to calculate the primary energy consumption based on the source type. This study showed a direction for updating the building-energy policy and regulations, as well as the potential of implementing ECMs, to improve the energy performances of Korean multifamily residential buildings.

scholarly journals A Life Cycle Cost Analysis of Structural Insulated Panels for Residential Buildings in a Hot and Arid Climate

Buildings ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 255
Author(s):  
Muataz Dhaif ◽  
André Stephan
Keyword(s):  
Energy Efficiency ◽  
Life Cycle ◽  
Life Cycle Cost ◽  
Energy Demand ◽  
Energy Use ◽  
Residential Buildings ◽  
Climatic Conditions ◽  
Building Envelope ◽  
Structural Insulated Panels ◽  
Operational Energy

In hot and humid climatic conditions, cooling tends to dominate building thermal energy use. Cooling loads can be reduced through the adoption of efficient building envelope materials, such as Structural Insulated Panels (SIPs). This study quantifies the life cycle cost and operational energy of a representative case-study house in Bahrain using SIPs and hollow concrete blocks (HCBs) for the envelope over a period of 50 years. Operational energy is calculated using a dynamic energy simulation tool, operational costs are calculated based on the energy demand and local tariff rates, and construction costs are estimated using market prices and quotations. The life cycle cost is quantified using the Net Present Cost technique. Results show that SIPs yield a 20.6% reduction in cooling energy use compared to HCBs. For SIP costs of 12 and 17 USD/m², the SIP house was cheaper throughout, or had a higher capital cost than the HCB house (breaking even in year 33), respectively. We propose policy recommendations with respect to material pricing, electricity tariffs, and energy efficiency, to improve the operational energy efficiency of houses in Bahrain and similar countries along the Arabian Peninsula.

scholarly journals Mass, Direct Cost and Energy Life-Cycle Cost Optimization of Steel-Concrete Composite Floor Structures

2021 ◽  
Vol 11 (21) ◽  
pp. 10316
Author(s):  
Stojan Kravanja ◽  
Uroš Klanšek ◽  
Tomaž Žula
Keyword(s):  
Life Cycle ◽  
Energy Consumption ◽  
Direct Cost ◽  
Composite Structure ◽  
Energy Efficient ◽  
Life Cycle Cost ◽  
Cost Optimization ◽  
Mixed Integer ◽  
Life Cycle Costs ◽  
Objective Functions

This paper presents a study showing the optimization of the mass, direct (self-manufacturing) costs, and energy life-cycle costs of composite floor structures composed of a reinforced concrete slab and steel I-beams. In a multi-parametric study, mixed-integer non-linear programming (MINLP) optimizations are carried out for different design parameters, such as different loads, spans, concrete and steel classes, welded, IPE and HEA steel profiles, and different energy consumption cases. Different objective functions of the composite structure are defined for optimization, such as mass, direct cost, and energy life-cycle cost objective functions. Moreover, three different energy consumption cases are proposed for the energy life-cycle cost objective: an energy efficient case (50 kWh/m2), an energy inefficient case (100 kWh/m2), and a high energy consumption case (200 kWh/m2). In each optimization, the objective function of the structure is subjected to the design, load, resistance, and deflection (in)equality constraints defined in accordance with Eurocode specifications. The optimal results calculated with different criteria are then compared to obtain competitive composite designs. Comparative diagrams have been developed to determine the competitive spans of composite floor structures with three different types of steel I beam: those made of welded sections and those made of IPE or HEA sections, respectively. The paper also answers the question of how different objective functions affect the amount of the calculated costs and masses of the structures. It has been established that the higher (more wasteful) the energy consumption case is, the lower the obtained masses of the composite floor structures are. In cases with higher energy consumption, the energy life-cycle costs are several times higher than the costs determined in direct cost optimization. At the end of the paper, a recommended optimal design for a composite floor system is presented that has been developed on the multi-parametric energy life-cycle cost optimization, where the energy efficient case is considered. An engineer or researcher can use the recommendations presented here to find a suitable optimal composite structure design for a desired span and uniformly imposed load.

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