Renovation Scenarios Research Articles

Decision Support System for the Sustainable Seismic and Energy Renovation of Buildings: Methodological Layout

In Italy, as in many other European countries, a large part of the real estate was built before the issue of restrictive regulations regarding seismic resistance and energy efficiency. Consequently, most existing buildings show inadequate structural and energy performance. However, although a combined renovation is highly recommended, and despite relevant tax incentives which are currently available, the building retrofit market is still struggling to take off. In fact, the lack of information and/or awareness of the involved parties and the consequent difficulty for condominiums to approve the retrofit works are often insuperable obstacles. A Decision Support System (DSS) may help in evaluating and comparing different combined renovation scenarios, thus promoting the regeneration of the building stock. This study presents a new methodology for the selection of the optimal building renovation scenario through a DSS, which is conceived as a tool to allow a quick, simple and effective identification of the best retrofit strategy, based on a priority scale (e.g., costs and duration of intervention, disruption to the occupants, environmental sustainability, energy savings, thermal comfort, structural safety). For this purpose, the DSS calculates suitable performance indices and relative costs. Finally, the system proposes a ranking of the best combined retrofit scenarios. This research study is still ongoing and next steps will deal with the calibration of the proposed methodology.

Calculation approach to building DCGLs of waste treatment facilility for Kori unit 1 decommissioning and comparative analysis of the results

The Derived Concentration Guideline Levels (DCGLs) of remaining buildings in decommissioning site realistically need to be considered because all nuclear power plants in Korea are operated with the adjacent plant in multi-unit site. In addition, a few buildings are expected to be utilized for the decommissioning such as waste treatment facility to reduce the final disposal volume of radioactive waste. Therefore, DCGLs of buildings postulated for the decommissioning of Kori site have been assessed by using RESRAD-BUILD code. As a result, DCGLs were derived, reflecting the site reuse criteria and input prameters based on site conditions and assumptions, and compared and analyzed how they differ from DCGLs of other nuclear plants depending on radionuclides. The occupancy and renovation scenarios were applied and more than half of the target radionuclides were conservatilvely evaluated in the occupancy scenarion, while some were evaluated in the renovation scenario. The approach and methodology presented in this paper, which can be considered at the level of the transition phase, can be utilized for deriving results that reflect reality at the time of license termination.

PARADIS - A process integrating tool for rapid generation and evaluation of holistic renovation scenarios

Recent research in building renovation seeks methods for the development of more holistic renovation scenarios that live up to a broader set of sustainability objectives and criteria, and that involve more stakeholders in the earlier stages of the design process. This paper presents a methodology for development of a Building Information Modeling (BIM) based decision support system PARADIS, which generates and evaluates optimal and holistic renovation scenarios tailored toward the renovation of dwellings in a Danish context. PARADIS supports the renovation sector with the following features: (a) optimizing the selection process of renovation alternatives, and the generation of renovation scenarios, through specific renovation typologies and constraints; (b) evaluating standard sustainability Key Performance Indicators (e.g. energy consumption, investment cost, indoor thermal comfort, etc.) over the generated renovation scenarios; and (c) visualizing the generated renovation scenarios for ease of comprehension by the designers, and for enabling discussion between expert stakeholders (i.e. engineers, contractors, facilities managers) and non-expert stakeholders (e.g. building occupants, owners, etc.). PARADIS thus supports informed decision making for optimal renovation scenario design. The first complete integrated toolchain, including a ready-to-release prototype of the PARADIS Revit plug-in, is demonstrated in this paper and empirically evaluated on a large apartment block in Denmark.

Robust and resilient renovation solutions in different climate change scenarios

Building renovation is currently urgent in order to decrease the energy consumption of a building stock. In order to achieve robust renovation scenarios, uncertainty quantification is needed. Climate change scenarios are important factors and need to be included in the analysis. In this paper, three climate change scenarios are applied probabilistically for a renovation scenario using dimensionality reduction techniques and further uncertainty propagation. The results show that RCP2.6 provides more robust results and saves on average 2. 105 CHF and 2. 105kgCO2eq. in a building life cycle comparing to RCP 8.5. The analysis under climate change is also compared to the probabilistic calculations under current climate and the results show the underestimation of both costs and environmental impacts when climate change is not included. It can also be clearly seen that even under the best case of RCP 2.6, building renovation is urgently needed to decrease the environmental impacts and costs.

Carbon Emission Reduction Potential in the Finnish Energy System Due to Power and Heat Sector Coupling with Different Renovation Scenarios of Housing Stock

In the pursuit of mitigating the effects of climate change the European Union and the government of Finland have set targets for emission reductions for the near future. This study examined the carbon emission reduction potential in the Finnish energy system with power-to-heat (P2H) coupling of the electricity and heat sectors with different housing renovation levels. The measures conducted in the energy system were conducted as follows. Wind power generation was increased in the Finnish power system with 10 increments. For each of these, the operation of hydropower was optimized to maximize the utilization of new wind generation. The excess wind generation was used to replace electricity and heat from combined heat and power production for district heating. The P2H conversion was performed by either 2000 m deep borehole heat exchangers coupled to heat pumps, with possible priming of heat, or with electrode boilers. The housing stock renovated to different levels affected both the electricity and district heating demands. The carbon emission reduction potential of the building renovation measures, and the energy system measures were determined over 25 years. Together with the required investment costs for the different measures, unit costs of emission reductions, €/t-CO2, were determined. The lowest unit cost solution of different measures was established, for which the unit cost of emission reductions was 241 €/t-CO2 and the reduced carbon emissions 11.3 Mt-CO2 annually. Moreover, the energy system measures were found to be less expensive compared to the building renovation measures, in terms of unit costs, and the P2H coupling a cost-efficient manner to increase the emission reductions.

New sustainability assessment model for Intelligent Façade Layers when applied to refurbish school buildings skins

In regard to increasing reports toward severe comfort problems and high energy consumption by educational buildings in many countries, a sustainable refurbishment for these edifices is urgently required. Using Intelligent Façade Layers as a protective cover with a variety of possible energy sources would be an innovative rehabilitation alternative, which until now has had outstanding performances in other architectural applications.This research paper, overcoming the lack of comprehensive assessments on Intelligent Façades, develops a new model to quantitatively assess the sustainability of these façades when applied to optimize existing educational architecture. This model combines the multi-criteria decision-making MIVES method with the Delphi technique, relying on literature, real projects and sensitivity analyses. The model considers the main economic, environmental and social aspects in its steps: 1) model boundaries, 2) experts’ qualification, 3) requirements tree, 4) weights assignment, 5) value functions, 6) sustainability indexes and 7) most sustainable alternatives. This model has been applied and validated in five Intelligent Façade Layers alternatives and three case studies at schools in Barcelona, Spain. This new approach proved highly reliable, showing the need for optimizations in both economic and environmental impacts applied to refurbishment scenarios. In this sense, future steps will design optimized alternatives.

Concept and Evaluation of Heating Demand Prediction Based on 3D City Models and the CityGML Energy ADE—Case Study Helsinki

This work presents a concept for heating demand and resulting CO2 emissions prediction based on a 3D city model in CityGML format in various scenarios under the consideration of a changing climate. In the case study of Helsinki, the Helsinki Energy and Climate Atlas, that provides detailed information for individual buildings conducting the heating demand, is integrated into the 3D city model using the CityGML Energy Application Domain Extension (Energy ADE) to provide energy-relevant information based on a standardized data model stored in a CityGML database, called 3DCityDB. The simulation environment SimStadt is extended to retrieve the information stored within the Energy ADE schema, use it during simulations, and write simulation results back to the 3DCityDB. Due to climate change, a heating demand reduction of 4% per decade is predicted. By 2035, a reduction of 0.7 TWh is calculated in the normal and of 1.5 TWh in the advanced refurbishment scenario. Including the proposed improvements of the district heating network, heating CO2 emissions are predicted to be reduced by up to 82% by 2035 compared to 1990. The City of Helsinki’s assumed heating demand reduction through the modernization of 2.0 TWh/a by 2035 is not achieved with a 3% refurbishment rate. Furthermore, the reduction of CO2 emissions is mainly achieved through lower CO2 emission factors of the district heating network in Helsinki.

Generation of whole building renovation scenarios using variational autoencoders

Buildings consume a huge amount of energy, resulting in a considerable impact on the environment. In Canada, almost 70% of the total energy used by the commercial and institutional sectors was consumed by Heating, Ventilation and Air-Conditioning (HVAC) and lighting systems, which makes them the main targets of energy performance optimization methods. Furthermore, based on a governmental report, 40% of Quebec university buildings are in poor or very poor shape regarding structure and materials, and require immediate renovation. Therefore, it is of utmost importance to reduce energy consumption, and this can be accomplished by improving the design of new buildings or by renovating existing ones. Moreover, Simulation-Based Multi-Objective Optimization (SBMO) models can be used for optimizing and assessing different renovation scenarios considering Total Energy Consumption (TEC) and Life Cycle Cost (LCC). The time-consuming nature of SBMO has triggered the development of simplified and surrogate models within the design process. This study proposes a generative deep learning building energy model using Variational Autoencoders (VAEs), which could potentially overcome the current limitations. The proposed VAEs extract deep features from a whole building renovation dataset and generate renovation scenarios considering TEC and LCC of the existing institutional buildings. The proposed model also has the generalization ability due to its potential to reuse the dataset from a specific case in similar situations. The performance of the developed model has been demonstrated using a simulated renovation dataset to prove its potential. The results show that using generative VAEs is acceptable considering computational time and accuracy.

Efficiency of green roofs and green walls as climate change mitigation measures in extremely hot and dry climate: Case study of Qatar

The main goal of this study is to assess the potential of green roofs and walls as a mitigation measure for the climate-change-driven growth of building energy consumption in extremely hot climates. A comprehensive, interdisciplinary methodology was developed that bridged climate change and building modeling. The residential building stock of Qatar was considered, with a two-story residential villa selected as a representative of the stock and consequently a case study. Weather scenarios were created for the years 2020, 2050, and 2080, and four building renovation scenarios were developed. The findings suggested that without any mitigation measures, residential building energy consumption in Qatar could increase by up to 9%, 17%, and 30% in 2020, 2050, and 2080, respectively. The addition of 5-cm expanded polystyrene and the installation of energy-efficient windows proved to be far more efficient than the addition of green walls and roofs under the climate conditions (30% reduction in energy consumption vs. 3%). Additionally, the environmental impact of green wall and roof maintenance, specific to Qatar, should be considered. However, in the final judgment, other positive effects of a green infrastructure (such as the effect on air quality, heat island effect, and health of the inhabitants) should be considered.

ENVIRONMENTAL CONSEQUENCES OF REFURBISHMENT VERSUS DEMOLITION AND RECONSTRUCTION: A COMPARATIVE LIFE CYCLE ASSESSMENT OF AN ITALIAN CASE STUDY

ABSTRACT In the building sector, new standards for energy efficiency are reducing the energy consumption and the carbon emissions for building operation to nearly zero. As a result, the greenhouse gas emissions and related environmental impacts from materials production, and especially insulation, are becoming key factors. In the near future, most of the building stock is expected to be refurbished and a great amount of construction materials will be consequently required. A relevant share of waste is generated from building construction and demolition and limiting the volume is a priority of the EU community. In this work the renovation of industrial buildings in a dismissed area located in Lecco, Italy, was considered as a case study. Five alternative construction systems (EPS, WOOD, ROCK, PU, HEMP) for renovating the building envelopes were assumed, and a life cycle assessment (LCA) adopted in order to measure the environmental impact of each alternative. The results were compared with a scenario which included demolition and reconstruction of a similar building with the same net volume and thermal resistance. The results showed that timber and concrete are the most environmentally friendly materials to rebuild the structures in case of demolition, contrary to steel which leads generally to higher environmental impacts, except land use. In general, EPS, WOOD and HEMP technological alternatives accounted for the highest scores, both in terms of burdens on the ecosystems and on depletion of resources, while ROCK accounted for the lowest scores. Finally, refurbishment scenarios generally accounted for a lower global warming potential (GWP) even if demolition, waste treatment and the benefit from recycling/reuse are taken into account.

Statistical method to identify robust building renovation choices for environmental and economic performance

Building renovation is urgently required to decrease the energy consumption of the existing building stock and reduce greenhouse gas emissions coming from the building sector. Selecting an appropriate renovation strategy is challenging due to the long building service life and consequent uncertainties. In this paper, we propose a new framework for the robust assessment of renovation strategies in terms of environmental and economic performance of the building's life cycle. First, we identify the possible renovation strategies and define the probability distributions for 74 uncertain parameters. Second, we create an integrated workflow for Life Cycle Assessment (LCA) and Life Cycle Cost analysis (LCC) and make use of Sobol’ indices to identify a prioritization strategy for the renovation. Finally, the selected renovation scenario is assessed by metamodeling techniques to calculate its robustness. The results of three case studies of residential buildings from different construction periods show that the priority in renovation should be given to the heating system replacement, which is followed by the exterior wall insulation and windows. This result is not in agreement with common renovation practices and this discrepancy is discussed at the end of the paper.

Applied Research of the Hygrothermal Behaviour of an Internally Insulated Historic Wall without Vapour Barrier: In Situ Measurements and Dynamic Simulations

The hygrothermal behaviour of an internally insulated historic wall is still hard to predict, mainly because the physical characteristics of the materials composing the historic wall are unknown. In this study, the hygrothermal assessment of an internally thermal insulated masonry wall of an historic palace located in Ferrara, in Italy, is shown. In situ non-destructive monitoring method is combined with a hygrothermal simulation tool, aiming to better analyse and discuss future refurbishment scenarios. In this context, the original U-value of the wall (not refurbished) is decreased from 1.44 W/m2K to 0.26 W/m2K (10 cm stone wool). Under the site specific conditions of this wall, not reached by the sun or rain, it was verified that even in the absence of vapour barrier, no frost damage is likely to occur and the condensation risk is very limited. Authors proposed further discussion based on simulation. The results showed that the introduction of a second gypsum board to the studied technology compensated such absence, while the reduction of the insulation material thickness provides a reduction of RH peaks in the interstitial area by 1%; this second solution proved to be more efficient, providing a 3% RH reduction and the avoidance of further thermal losses.

Methodology for Evaluation and Development of Refurbishment Scenarios for Multi-Story Apartment Buildings, Applied to Two Buildings in Denmark and Switzerland

Renovation of existing buildings is an indispensable part of achieving European efficiency and environmental targets. This paper applies different assessment methodologies to find optimal renovation, given different evaluation criteria. The performed literature study identifies the cost-optimal methodology employing Life Cycle Cost (LCC) calculation as one of the most common assessment methods. This paper proposes a new renovation assessment method targeted to the early design phases of specific building projects. The method has a simple structure, and can be used as a roadmap of necessary activities for obtaining solid building knowledge and required energy and cost calculations. The methodology is based on linking economic and energy efficiency parameters into defined cost-effective value, calculated for all investigated renovation actions. The cost-effectiveness value is used for ranking and selecting the most appropriate single renovation actions to form renovation packages, which can be further examined in detail (for example, with LCC). To demonstrate the method, evaluate the strengths, and identify the weaknesses, it is applied to case study buildings in Denmark and Switzerland. The results show that, in the initial stage, the proposed cost-effectiveness representation can be used successfully to compare and evaluate different envelope elements and systems. Cost-effectiveness also provides rational results on a package level. Further work is still required in the area of evaluation of energy supply and renewable energy production systems.

Evaluation of School Building Energy Performance and Classroom Indoor Environment

Existing building stock represents potential for energy saving renovations. Energy savings and indoor climate comfort are key demands for sustainable building refurbishment. Especially in schools, indoor comfort is an extremely important issue. A case study of energy consumption in selected school buildings in temperate climatic conditions of Central Europe region was performed. The studied buildings are representatives of various school premises constructed throughout the last century. The evaluation was based on data analysis of energy audits. The goal was aimed at assessment of the school building envelopes and their influence on energy consumption. One of the studied schools was selected for detailed evaluation. The school classroom was monitored for indoor thermal and visual environments. The monitoring was performed to compare the current state and renovation scenarios. Results of the evaluation show that the school buildings are highly inefficient even if renovated. Indoor climate in classrooms is largely influenced by windows. Solar gains affect interior thermal stability and daylighting. Thermal insulation quality of building envelopes and efficient solar shading systems appear to be fundamental tasks of school renovation strategies.

A new approach in the refurbishment of the office buildings – from standard to alternative nearly zero energy buildings

ABSTRACT The government of Cyprus has developed packages addressing the energy performance of non-residential buildings, in order to achieve the national energy reduction objectives. Currently, Decree 366/2014 is in force, defining the requirements for a building to qualify as a nearly Zero Energy Building (nΖΕΒ). However, this falls short of addressing sufficiently the high cooling energy demand of buildings in Cyprus. This paper examines the energy and economic viability of various refurbishment scenarios by considering a public office building in the city of Limassol as a case study. The energy performance of the building was analysed first for its current state and also according to nZEB standards. In addition, a set of supplementary measures was examined, to develop a cost-effective alternative nZEB energy refurbishment model. Based on the results, the existing legislation, defining an nZEB is reconsidered prompting a proactive discussion towards the improvement of the current energy regulating Directives.

A spatio-temporal life cycle assessment framework for building renovation scenarios at the urban scale

Reducing the energy consumption of buildings is a priority for carbon emissions mitigation in urban areas. Building stock energy models have been developed to support decisions of public authorities in renovation strategies. However, the burdens of renovation interventions and their temporal distribution are mostly overlooked, leading to potential overestimation of environmental benefits. Life Cycle Assessment (LCA) provides a holistic estimation of environmental impacts, but further developments are needed to correctly consider spatio-temporal aspects.We propose a spatio-temporal LCA framework to assess renovation scenarios of urban housing stocks, integrating: 1) a geospatial building-by-building stock model, 2) energy demand modelling, 3) product-based LCA, and 4) a scenario generator. Temporal aspects are considered both in the lifecycle inventory and the lifecycle impact assessment phases, by accounting for the evolution of the existing housing stock and applying time-adjusted carbon footprint calculation.We apply the framework for the carbon footprint assessment of housing renovation in Esch-sur-Alzette (Luxembourg). Results show that the renovation stage represents 4%–16% of the carbon footprint in the residual service life of existing buildings, respectively after conventional or advanced renovations. Under current renovation rates, the carbon footprint reduction would be limited to 3–4% by 2030. Pushing renovation rates to 3%, enables carbon reductions up to 28% by 2030 when combined with advanced renovations. Carbon reductions in the operational stage of buildings are offset by 8–9% due to the impacts of renovation. Using time-adjusted emissions results in higher weight for the renovation stage and slightly lower benefits for renovation.

Effect of Embodied Energy on Cost-Effectiveness of a Prefabricated Modular Solution on Renovation Scenarios in Social Housing in Porto, Portugal

A large-scale energy renovation intervention in existing buildings has been consistently presented as the most significant opportunity to contribute to achieving the European targets for 2030 and 2050. One of the key points for such achievement is the cost-effectiveness of the interventions proposed, which is also closely related to decent housing affordability. Prefabricated modular solutions have been pointed out as a pathway, but there are knowledge gaps regarding both its cost-effectiveness and its environmental performance. Considering a social housing multi-family building in Porto, Portugal, as a case study, this research employs energy simulations, a cost-optimal methodology and a life cycle analysis approach to assess the influence of considering embodied energy and emissions in cost-effectiveness calculations. In general terms, the hierarchical relation between calculated renovation scenarios remain identical, as well as the choice of the cost-optimal combination, which can reduce primary energy needs by 226 kWh/(y.m2). However, embodied carbon emissions and embodied energy of the materials used in the calculations, which are indicative of the sustainability of such interventions, increase the energy and carbon emissions associated to each renovation package by an average of 43 kWh/(y.m2) and 9.3 kgCO2eq/(y.m2), respectively.

Investigating eco-efficiency procedure to compare refurbishment scenarios with different insulating materials

Abstract The paper presents a set of situations regarding eco-efficiency. It is built on both environmental and economic performances. Those performances are computed respectively from LCA and from WLC. The present eco-efficiency procedure considers both matrix and ratio methods. This paper investigates different alternatives for refurbishment insulation of a single-family house located in the North of France. The analyzed refurbishment scenarios consider different insulating materials: standard glass wool, hemp concrete, cellulose fiber, expanded polystyrene (EPS), extruded polystyrene (XPS), and rigid foam polyurethane. The different alternatives are compared using the eco-efficiency procedure.

Effects of Improved Energy Performance of Buildings on Air Quality over the Greater Athens Area

Air pollution episodes are common in the Greater Athens Area (GAA) because of its pollutant source concentration, complex topography, and regional meteorology. For the GAA, over 90% of the existing building stock is classified below energy class B, so the effects of upgrades on energy savings are obvious and have been widely discussed. The present study focuses on the potential effects that a realistic level of implementation of the EPBD will have on the air quality over the GAA. Three renovation scenarios were examined with an implementation rate of 20%. Numerical simulation of primary pollutants’ dispersion over the GAA was performed using the CALPUFF modelling system. Ground level concentrations of SO2, NOx, CO and PM10 were calculated, taking into account pollutant releases from major roads and highways, passenger ports and cargo transport, residential heating installations and major industrial installations. The required source data was taken from National and European statistics, demographics and local topography while the Weather Research and Forecasting (WRF) model was implemented for the required high resolution meteorological field data. The modelling system was first successfully validated by comparison with available measurements of pollutant concentrations and then applied to case studies of EPBD implementation. Reductions up to ∼6% were found in the ground level concentrations of major pollutants.

Environmental Payback of Renovation Strategies in a Northern Climate—the Impact of Nuclear Power and Fossil Fuels in the Electricity Supply

The aim of this study is to assess how the use of fossil and nuclear power in different renovation scenarios affects the environmental impacts of a multi-family dwelling in Sweden, and how changes in the electricity production with different energy carriers affect the environmental impact. In line with the Paris Agreement, the European Union has set an agenda to reduce greenhouse gas emissions by means of energy efficiency in buildings. It is estimated that by the year 2050, 80% of Europe’s population will be living in buildings that already exist. This means it is important for the European Union to renovate buildings to improve energy efficiency. In this study, eight renovation scenarios, using six different Northern European electricity mixes, were analyzed using the standard of the European Committee for Standardization for life cycle assessment of buildings. This study covers all life cycle steps from cradle to grave. The renovation scenarios include combinations of photovoltaics, geothermal heat pumps, heat recovery ventilation, and improvement of the building envelope. The results show that while in some electricity mixes a reduction in the global warming potential can be achieved, it can be at the expense of an increase in radioactive waste production, and, in mixes with a high share of fossil fuels, the global warming potential of the scenarios increases with time, compared with that of the original building. It also shows that in most electricity mixes, scenarios that reduce the active heat demand of the building end up in reducing both the global warming potential and radioactive waste, making them less sensitive to changes in the energy system.