Energy retrofit of historic buildings: Environmental assessment of cost-optimal solutions (original) (raw)
Life cycle assessment of energy retrofitting solutions for Portuguese buildings from the 70s
In Portugal, the energy retrofitting of existing buildings from the 70’s has high potential savings to be explored. This paper is focused in a real case study of a multi-residential building located in Porto, Portugal, and constructed in the end of the 60’s. Several solutions for the thermal retrofitting of the building envelope are designed and comparatively accessed, considering their environmental, societal and economic performances. The environmental performance is assessed using the SimaPro life-cycle assessment software and the economic and societal (occupant’s comfort) benefits are assessed using standardized approaches. The MARS-SC method is used to compare and rank the thermal retrofitting solutions at the level of their sustainability. As main outcome, this work allows to conclude that it is possible to improve the indoor comfort and energy performance of an existing building, using standard solutions and at an adequate level of initial investment. All proposed solutions presented very significant energy saving.
Journal of Cleaner Production, 2018
Building retrofits are often motivated by the desire to improve the energy efficiency of a building. However, environmental burdens associated with additional materials used to accomplish energy efficiency are not usually taken into account. Life-cycle assessment (LCA) and life-cycle cost assessment (LCCA) approaches have been extensively applied to analyze building environmental impacts and costs. However, LCA and LCCA are time-consuming and resource-intensive and are usually performed in late design stages when significant reduction in total life-cycle impacts is costly to achieve. The aim of this article is to present an integrated, streamlined LCA-LCCA approach to building retrofits to provide feedback on environmental impacts and costs at early-design stage decisions. We propose a framework that fully integrates a streamlined embodied LCA, statistical-based operational energy, and cost models. This approach incorporates uncertainty to address the lack of information in early design stages by using the building attribute to impact algorithm approach, which includes structured under-specification and probabilistic triage. An automated process enables several scenarios to be assessed and compared as a means of better informing designers of the relative environmental impact of materials and dimensioning choices. It is demonstrated that by selecting very few attributes and then comparing several options, robust retrofit decisions can be made in early-design stages, thereby promoting a reduction in environmental impacts and costs. 1 Introduction Building retrofits can promote a significant reduction in the environmental load and operating costs of the European building stock (European Comission, 2012). The European Commission established a long-term objective of decreasing the CO2-emission levels for the building sector by 88-91%, compared to 1990 levels, to be implemented by 2050. In order to achieve this target, which is also a prerequisite for meeting other EU economic and climate goals, the EU
The paper reports a research started with a simple case study and a simple question. The case study is an Italian social housing quarter, served by a district heating system, which needs – as many others in many other countries – a reasonable refurbishment. The question is: «may savings, derived from its energy retrofit, pay refurbishment costs?». In order to answer to this question, we studied the economic sustainability of different retrofitting strategies and assessed their Return of Investment. In the first phase of the work, design choices were roughly defined, with a sketch of basic details and a rough energy demand calculation, according to national standards. In the second phase, design choices were detailed in order to have a reliable assessment of costs of each refurbishment strategy and to investigated the most probable impact of thermal bridges (balconies, windows, pillars, beams, etc.) on the real energy consumption for heating and, consequently, on the Return of the In...
The Evaluation of Historic Building Energy Retrofit Projects through the Life Cycle Assessment
Applied Sciences
The built environment sector is one of the main sources of greenhouse gas emissions and resource depletion that contributes to the climate change crisis. The European Commission, in the “Green New Deal”, highlights that the sustainable regeneration/requalification of existing buildings plays a fundamental role to maximize the objective of decarbonization and resource conservation for 2050. The aim of this study was to understand how historic buildings’ energy retrofit projects can contribute to achieve this goal. In this study, we made a life cycle assessment to evaluate an energy retrofit project of Villa Vannucchi, an historic building located in San Giorgio a Cremano (Naples). The results of this application showed that the use of hemp material, for walls’ thermal insulation, significantly reduces the percentage of environmental impacts in the entire material life cycle (compared with traditional materials). This was because the plant removes a significant percentage of CO2 alrea...
Energy efficient retrofit and life cycle assessment of an apartment building
Energy Procedia, 2015
While new buildings should be designed as intelligent low or zero-energy buildings, refurbishment of the existing building stock may present even a greater challenge, when in particular financing of the necessary investments to energy saving measures poses the biggest barrier. As the residential sector in the EU is responsible for about 40% of the total energy consumption and up to 40 % of the total carbon dioxide emissions, the residential building stock offers high potential for energy savings. By applying the life cycle assessment, it is possible to optimise the social, economic and environmental aspects, starting from the extraction of raw materials, up to the final disposal of waste materials.A case study of a selected representative residential building located in Slovakia is presented, for which the cost-optimal levels of energy performance are determined in terms of life-cycle costs of the building. Three variants of renovation were defined, each variant having different level of thermal insulation of building constructions. The method of Life-Cycle Costs was used to evaluate the economic feasibility of the suggested renovation scenarios for the apartment house.
The application of retrofit actions to existing building stocks can improve the energy performance of the residential sector. In this context, particular attention should be given to historical buildings, which represent a large part of the Italian building stock. To improve the energy performance of them, adequate retrofit actions must be applied. Many studies and regulations have focused on identifying the best refur-bishment measures. However, the selection of these measures is difficult due to restrictive regulations, which are dictated by the Ministry of Cultural Heritage and Activities, high retrofit costs, and variable climate zones. Thus, energy renovations in Italian buildings are not simple, and it is very difficult to find generic solutions that can be applied to buildings across the entire territory. In this paper, the authors investigated the most common retrofit solutions used in Italy, focusing in particular on the energy performance of historical building envelopes. First, energy performance analyses were conducted for two typical base cases in four different Italian cities using TRNSYS software, and some common retrofit measures were analysed. In some cases, the results showed Primary Energy saving of 44.6% (sample A) and 56.7% (sample B). Furthermore, these were used to identify different energy and economic impacts associated with the same refurbishment measures in different climatic contexts, highlighting the non-existence of a generic solution suitable for all regions or countries.
Under the current Energy Performance of Buildings Directive, EU countries must set building energy renovation as a goal for future development of the cities. The 22@ district of Barcelona is one of the most thriving innovation districts of Europe with an increasing market for office buildings. In this framework, the present paper evaluates the effectiveness of a series of strategies considered the real case project of the energy retrofit of an existing building in 22@. In particular, the study presents the results of different scenarios of building retrofits, where simulations of dynamic envelopes are performed, with the inclusion of a conventional ventilated façade, Living Green Walls and Phase Change Material (PCM) for thermal energy storage. The different scenarios are compared in terms of energy performance, enhanced comfort and cost-benefit analysis. The benefits of latent thermal energy storage, improved thermal inertia and evapotranspiration of the vegetated elements are also assessed. Eventually this study helps understanding the feasibility of the implementation of the nZEB standard in energy retrofit of buildings in the specific context of Barcelona and Spain. 1. Introduction The massive urban development is altering the land surface by concentrating materials which effectively retain heat and create impervious surfaces, thus affecting urban local climate and urban hydrology. Moreover, tall buildings provide multiple surfaces for the absorption of solar radiation that is subsequently reradiated as heat, thus enhancing the efficiency with which urban areas are warmed up [1]. Building renovation is a main issue of recent European policies towards energy efficiency. Today's renovation projects have the challenges of improving the energy efficiency in order to reach the goals of zero emission in the building sector while improving their social and economic value, securing a sustainable use of resources [2] and minimizing the deleterious effects of buildings in the urban environment. The renovation of the building envelope, are a key factor in the energy rehabilitation of buildings and the urban environment. This paper describes three renovation strategies: living walls, ventilated facades with fibre-cement cladding and ventilated facades with PCM materials [3,4,5].
Energy and Buildings, 2014
Due to the effects of a building's whole life cycle processes on the environment and economy, there is an increasing interest in sustainability assessment of new and existing buildings. In Turkey, there is a large building stock constructed before legislative measures on energy efficiency were implemented. This article defines an environmental and economic sustainability assessment method to evaluate the effectiveness of existing residential building retrofits for reducing their space heating energy consumptions and the resulting emissions. The proposed method is based on the life cycle assessment method, and evaluates the environmental and economic sustainability performance of building envelope retrofits; i.e., adding thermal insulation and replacing windows. The intent of this method is to support the decision making process of building owners, users or architects in selecting the most beneficial retrofit alternatives in Turkey. In its current state, the database based on this methodology covers detached buildings located in Istanbul, with a natural gas-fired central heating system.
Building retrofit addressing occupancy: An integrated cost and environmental life-cycle analysis
Energy and Buildings, 2017
Building retrofit can lead to important savings in operating cost and environmental impacts; however, the actual savings depend on future house occupancy, which is generally not taken into account. The goal of this article is to carry out an integrated (cost, environmental and energy) life-cycle (LC) assessment of alternative roof and exterior-wall insulation retrofit strategies for a single-family house addressing occupancy. Alternative scenarios were defined by type of use (residential and office) and occupancy level (low and high), set-points and family size. LC impacts were calculated for five environmental categories and non-renewable primary energy showing that an insulation level threshold (where total LC impacts are minimized) can be identified for exterior-wall retrofit (60-70 mm for all scenarios) and roof retrofit (90-100 mm for low residential occupancy; 80-90 mm for high residential occupancy and office use). Recommendations can be provided to enhance the retrofit performance of historic buildings in Southern Europe, depending on their use and occupancy level. Highly-insulated retrofit is more beneficial for high occupancy levels with higher thermal comfort conditions. No benefit is derived from incorporating insulation for lower comfort conditions. Interior insulation on exterior walls presents higher savings than exterior insulation.