Methodological approach for performance assessment of historical buildings based on seismic, energy and cost performance: A Mediterranean case

Highlights

• Passive, active and combination packages of retrofit measures evaluated to find appropriate energy and cost performance.

• Implementation to the exterior wall and HVAC system replacement provides the highest performance.

• Seismic and energy retrofit measures show synergistic effect for historical building renovation.

• This approach can be applied to the historic building before the re-function/renovation process.

Abstract

Historic buildings need to be re-functionalized because of environmental factors, economic reasons, socio-cultural changes. During the re-functionalization-renovation period, only the seismic performance of the building is analyzed to sustain the historic building according to law and legislation. However, the historic buildings show a considerable energy saving potential. Therefore, the performance assessment of historic buildings requires multidisciplinary approach, which examines both energy and seismic issues. The study aims to demonstrate how the energy and seismic performance improvement of a re-functioned historic building conducted with an integrated approach based on four phases: 1) evaluating the energy performance of the existing building, 2) determining energy & seismic retrofit packages 3) the energy and cost performance evaluation of retrofit packages 4) analyzing the performance of the retrofit measures. A detailed energy simulations used for finding the effects of energy measures that are passive, active, and their combinations by taking into consideration the historical value of the buildings. Life-cycle cost analysis is applied to find the best retrofit strategy for the historical building case by using the net present value method. The proposed methodology has been applied to a historical building in a Mediterranean City, İzmir to find the best retrofit measures for improving the performance of the building. Results show that the implementation of the external wall and applying the new HVAC system are the most effective measures considering both energy, seismic and cost performance. The study indicates that an integrated approach can improve both energy, seismic and cost performance of the historic buildings.

Introduction

The building sector is one of the primary CO₂ emission sources with its 36% share without a doubt, and it is also has a 40% share in energy consumption [1]. European Union (EU) published Directive 2010/31/EU of the European Parliament and of the Council of May 19, 2010 on the energy performance of buildings to indicate the target such as cost-optimal energy retrofit actions [2]. Measures for the improvement of energy efficiency are shown in Directive 2012/27/EU on energy efficiency to accomplish the target of a 20% decrease in primary energy consumption [3]. Directives of EU Ecodesign, the Energy Performance in Buildings Directive 2002–2010, the Energy Efficiency Directive 2012 and different national standards provide actions for energy efficiency in building [1,[3], [4], [5]]. Between 1990 and 2016, energy efficiency in the building sector increased by 35% and an average rate of 1.6% per year. This improvement can be achieved mostly with the use of more efficient heating appliances and the renovation of existing systems [6].

In Turkey, energy efficiency in buildings became significant with the standard on TS825 – Thermal Insulation Requirements for Buildings, which identified the compulsory heat transfer coefficient for wall, window, floor, and roof. TS825 – Thermal Insulation Requirements for Buildings involves method, standards, and minimum performance criteria about energy performance parameters, energy performance document, and the energy performance calculations [7]. According to the directive, the existing building especially built after 2000, must provide requirements that are mentioned in TS – 825. However, this directive does postulate historic buildings as an existing buildings. There are guidelines for improving the energy efficiency of historic buildings in Europe, but there is no guideline regards the energy performance of the historic building in Turkey.

Most of the building stock has been built in periods when energy efficiency is not on the agenda. Historic buildings have a substantial percentage in the existing building stock, especially in the Mediterranean region. Therefore, historic buildings have respectable energy-saving potential. While determining the energy-efficient measures, attention to the preservation of the historical value of the building becomes significant. The share of these buildings in building stock is over 22% [8], and renovation practices create tremendous economic impact, which is not discussed for historical buildings considering their cultural value. Nevertheless, a large number of these buildings re-functioned and used, which creates a significant impact on both the environment and economy.

There is comprehensive literature that examines only energy, cost and environmental impact in the built environment. Şahin et al. have investigated the most effective energy retrofit package to reduce the energy consumption of public buildings. As an energy retrofit packages, air filtration, changing the heating system, applying heat insulation between the roof and the attic layer, heat insulation application to the wall and floor were evaluated. The energy-saving potential of retrofit packages obtained more than 34% without damaging the heritage value [9]. In the study, the application of thermal insulation on the walls, replacement of windows, application of sun shading, application of photovoltaic panels and application of all proposed measures were evaluated with the simulation program. Accordingly, a combination of all proposed measures case, 27.7% energy saving has been achieved [10]. The study carried out in the historical city center, which was damaged by the earthquake in Italy and proposed application of different thermal insulation materials to improve the building thermally. The proposed building materials, innovative thermal insulation materials such as aerogel, vacuum thermal insulation panels, and the use of conventional thermal insulation materials such as EPS were evaluated. By application of the measures, 50% of energy-saving was achieved in masonry structures [11]. The study conducted in Italy aimed to reduce energy consumption, CO₂ emissions and increase the use of renewable energy. Energy measures without damaging the historical value of the building include; changing the roof, window and wall elements, mechanical ventilation system application, PV panel application, heat pump, and floor heating. In this study, energy consumption was reduced by the simulation method, while solar and photovoltaic panels were used to reduce energy consumption [12]. Bellia et al. have aimed to reduce the energy consumption value by using photovoltaic panels on the roof in a palace building in Naples. The aim was to use most of the daylight and reduce the energy consumed for lighting by applying the photovoltaic (PV) panels [13]. In another study conducted in Italy, it is envisaged to improve energy efficiency with the addition of the modern building to a historic public building. The application of the thermal insulation layer to the walls, replacement of glazing and for the floors are the energy-efficient retrofit interventions that implemented both modern and historic buildings [14]. In a study conducted for the buildings located in three different regions in the Baltic Sea region, the retrofit alternatives, replacing the heating-cooling system and changing the consumed resources, were chosen as the most energy-saving interventions. According to the study, energy savings are affected by building type, thermal transmittance of existing building, service system and energy efficiency target [15]. In another study, Cornaro et al. have discussed the simulation, on-site measurement, and energy improvement suggestions. It was determined that approximately 40% of energy savings were achieved in the case of heat insulation application and replacing the glazing without damaging the historical value of the building. Also, applying high insulation plaster could provide 38% energy saving [16]. Fatiguso et al. have determined the thermal conductivity values of the wall, window, roof and basement floors of the building by on-site measurements. In this study, it was shown that innovative building materials, thermal insulation panels, aerogel heat insulation layers and phase changing materials, affect the energy efficiency of historical buildings [17].

In these studies, where simulation or on-site measurement techniques are used, priority has been given to the historical value of the building. Although these studies have generally focused on the energy efficiency parameter, cost-effective energy improvement proposals have gained importance especially in recent years after the publication of the European Union (EU) Energy Performance Directive of Buildings (EPDB) – 2010 [2]. Ascione et al. have proposed energy-efficient methods within a cost perspective for a 15th – century building in Italy. Proposed retrofit measures involve changing the glazing type, enhancing the thermal insulation of the wall and attic and applying a more energy-efficient heating-cooling system. In another study, conservation, architectural, structural, energy and cost-optimal issues were discussed [18]. Tadeu et al. have discussed the application of energy-efficient retrofit packages integrated with cost optimality that assess the environmental impacts of historical buildings. The study stated that both cost and life-cycle environmental impact could be decreased while determining the energy-efficient measures [19]. In a study conducted in Germany, the cost analysis of measures was found by the net present value method. In this study, it has been determined that energy prices have a significant impact on the cost and hence the selection of the optimal improvement study [20]. Arumagi et all. Have aimed to increase the energy efficiency of the building by preserving the historical value of the building for a historical wooden building by using net present value [21]. Cristina et al. have analyzed the two different retrofit scenarios with the consideration of both energy and cost parameters [22]. Ascione et al. have applied the multi-objective methodology that interests both energy, cost and environmental aspects of building retrofit [23]. As a result of the study conducted in Italy, Ascione et al. have said that ‘‘selection of the energy efficiency measures is a multi-objective optimization problem’’ [24]. Cirami et al. have discussed the retrofit strategy with suitable materials and solutions by providing energy and cost-saving [25]. Pisello et al. have proposed smart and innovative integrated systems for providing energy saving in historical buildings [26].

Today, many historical buildings lose their original function and have a different role. The re-functionalization is the implementation of the interventions required by the decision to use the cultural property for a new purpose within the scope of the restoration/conservation project. Following the Venice Charter, the regulations developed by The International Council on Monuments and Sites (ICOMOS) established by conservation experts in 1965, the issues to be considered in the restoration of historical buildings, and the principles to be followed were defined in detail [27]. ‘‘Declaration on the Protection of the Architectural Heritage of ICOMOS Turkey” has published in 2013 to reconcile with international rules of conservation law and the conservation law of Turkey and define the basic concepts of conservation. According to the declaration, during this re-function process, the buildings are upgraded to an acceptable standard, but originality, integrity, and meaning of building must be respected. According to ICOMOS, there is a need for contemporary approaches for conservation to provide environmental sustainability [28]. Specific methods, systems, and materials must be investigated to determine a proper retrofit solution for historic buildings. For providing sustainability of historic buildings, during the renovation period, seismic and energy retrofit studies can be critical issues.

Both seismic strengthening and energy efficiency improvement become quite common practices in conventional building practices, yet these are mostly invasive and complicated issues in the case of historical buildings [29]. Ascione et al. have been discussed the multidisciplinary approach to structural and energy diagnosis and performance evaluation of the historic building. A numerical model for structural analysis and dynamic model for energy performance for heating and cooling of space has been done [30]. D'angola et al. have compared the existing and post-retrofit performance of the non-historic building to analyze the efficiency of interventions [31]. Artino et al. have proposed the methodology for reinforced concrete framed buildings that includes the replacement of the external layer of double-leaf infill walls with high-performing aerated air concrete (AAC) blocks [32]. De Vita et al. have evaluated the effects of most used seismic retrofitting interventions on the energy performance of historic masonry buildings [33]. Coppola et al. have proposed the seismic lightweight structural plaster to provide the energy-saving and seismic performance of masonry buildings [34]. Gkournelas et al. have examined the combination of seismic and energy retrofitting of existing reinforced concrete buildings. According to the study, a combined retrofit study is more cost-effective than single energy or seismic retrofit scenario [35].

There is a knowledge gap in literature where historical buildings need both seismic retrofit to increase structural integrity and lifetime and energy retrofit when reuse of the building. Such an integrated approach requires a cost-optimal method for the energy and seismic retrofit of the historic building. This study aims to investigate such a methodology to assess the cost-effective energy and structural performance of a historical building for its life cycle.