Use of Roof and Facade Integrated Active Systems in Historic Buildings

Use of Roof and Facade Integrated Active Systems to Achieve Energy Gains in Historic Buildings

Abstract

Roof and facade integrated system design represents important building technologies that facilitate architects in the process of energy-efficient building design. Particularly, the renewal of existing and historic building stock alongside new construction with energy-gaining systems is a preferred approach in addressing national and international energy requirement concerns. However, design recommendations proposed for new buildings do not always respond equally effectively to existing buildings, and especially to historic buildings with established historic identity. Historic structures differ from other existing buildings in their construction techniques, materials, facades, and cultural identities, most importantly in being period buildings. What is the applicability of period structures with contemporary building technologies? How can building technologies and materials be applied to historic buildings? This study will demonstrate the advantages and disadvantages resulting from the architectural integration of roof and facade integrated active systems that could serve as solutions for achieving energy gains in historic buildings that have survived to the present day.

1. Introduction

Energy is the most significant problem of the 21st century and the global crisis. 70% of the energy consumed in our country is imported. If we consume this imported energy efficiently, it is possible to achieve a 30% gain. In Turkey, 35% of energy and approximately 40% of total electricity consumption are used in buildings [1]. According to the 2001 Turkish Statistical Institute building census data, the existing building stock in our country stands at 7,838,635. This figure resulted from a 79% increase compared to 4,387,971 buildings determined in the 1984 census conducted before 2000. Since Turkish Statistical Institute building census work continues, this information has not been updated [2]. Turkish Statistical Institute construction permit statistics for 2010-2015 presented in Tables 1 and 2 show building permits issued and building occupancy certificates by year, with historic buildings and the total number of documented buildings for that year. However, the current inability to determine the number of illegal building stock, construction activities not being pursued due to various reasons such as cooperative disputes or financial difficulties of contractors despite building permits being issued, and the high costs of title deed and municipal fees even after the building permit stage to proceed to condominium ownership, result in the number of registered buildings not mathematically matching the actual number of existing buildings in Turkey. Accordingly, following the Energy Efficiency Law enacted in 2007, the requirement for buildings to obtain energy identity certificates became mandatory during the process of obtaining building permits and building occupancy certificates. For new buildings, this requirement applies during the building permit issuance stage, and for existing buildings, during the building occupancy permission stage.

As a result, because the energy identity certificate is a new regulation and the number of existing buildings is high, the energy issue in buildings has not yet been effectively utilized.

According to 2015 registered building statistics jointly prepared by the Turkish Statistical Institute and the Ministry of Culture and Tourism, there are a total of 93,587 historic buildings in our country, classified as civil architecture, religious, cultural, administrative, military, industrial, and commercial structures (Table 3) [3]. Within the large number of existing building stock, there are also historic structures that have maintained or have maintained their structural and functional existence but await renewal. Historic buildings comprise approximately 1% of the existing building stock. Most of these buildings were constructed in the late 19th and early 20th centuries. These structures, which define and establish the history and identity of cities, are unpreserved cultural heritage assets. Beyond their historic value, these buildings must be renewed regarding energy usage to keep pace with today's energy crisis and ever-increasing consumption needs, and to meet comfort conditions and heating and cooling requirements [4]. However, in application projects prepared today for the restoration and renovation of historic buildings, ideas for effective energy utilization are not being developed. There is concern that the historic building would be damaged. In restoration (returning to original state) and renovation (renewal) applications conducted in the 21st century, there has emerged a need for sustainable approaches with ecologically and energy-efficient design. However, to make building systems energy efficient, it is necessary to benefit from advanced building technologies. These technologies must be applied to the building form, identity, and appearance in such a manner as to minimize disruption to the building's overall integrity. A construction process that does not compromise the building's integrity can only be achieved through an integrated design process of high energy-performance new and existing buildings characterized by low energy consumption and quality indoor environmental values [4]. Nearly all historic structures were designed in accordance with passive design principles. However, changes in comfort standards today and advancing technology prevent these historic buildings from being used while preserving their original characteristics. For this reason, during the renewal stage, by designing active systems integrated with the building to achieve energy gains, technologies that do not harm the historic structure can adequately respond to requirements within reasonable parameters. To become acquainted with integrated renewable and clean energy system technologies in historic buildings, it is considered necessary to first explain the concept of building-integrated system design.

2. Building-Integrated Active Systems

Building-integrated system design is a design approach that has been incorporated into the architectural design process, working in conjunction with building passive design systems that guide the building's form and planning, with the objective of maximizing the energy obtained [5]. Building-integrated system technologies are not disconnected, installed systems on the building, but rather integrated ones. These are integrated systems that the architect selects during the design process, which can provide good facades in terms of color, material, size, and presentation in the building, can implement good engineering solutions, allow the use of new technologies and materials (innovative, smart materials), and most importantly, can achieve energy gains [5]. In this context, to enable comparison with existing structures, which are historic buildings, it is considered beneficial to include examples of the types of active systems and technologies used in new buildings, primarily intended for energy gains and requirements, within the study content. 2.1. Building-Integrated Active Energy Systems

2.1.1. Building-Integrated Solar Cells (BISC)

BISC technology uses solar cells that convert solar energy into electrical energy and manifests itself through building-integrated system design. Building-integrated solar cell structural elements entered the market in the 1990s and generated considerable demand from designers. Compared to the past century, it has enabled and continues to enable with improved technology the effective use of energy in both new buildings and renovated buildings. Sometimes serving as multifunctional building elements, more often they become the building envelope itself. These systems can be connected to main electrical grids or operate as independent systems [6]. With an integrated architectural approach, BISC is preferred because it can address aesthetic concerns (Figures 1-2-3), can be easily applied and implemented at lower costs, has many alternatives for roof or facade applications, demonstrates uninterrupted performance, can be applied to existing and old buildings through renovation and restoration decisions, and provides geometric application convenience by being installed as closed grids.

2.1.2. Building-Integrated Collectors (BIC)

With collector elements, solar energy is converted to thermal energy for use. These are systems where collector technology has been developed to provide input to integrated design in buildings (Figures 4-5). BISC/C can perform heating and cooling with solar energy, provide hot water, and be applied modularly with solar cells because

2.1.3. Building-Integrated Solar Cell/Collector (BISC/C)

This system is a unique combination of collector system and solar cell system. This combination utilizes the 10-20% of sunlight that conventional solar cells convert to electricity by preventing radiation losses and converts the remaining 80-90% of sunlight to heat for use [10]. The ideal operating temperature for solar cells is calculated as 25oC and below. A solar cell operating in an area with an ambient temperature of 25oC reaches a cell temperature of 45oC. Faced with this situation, hybrid systems have been developed both to benefit from this heat obtained by solar cells and to cool the solar cell. In this way, both electricity and hot water or air are provided. While cooling the solar cell increases efficiency on one hand, thermal energy becomes usable on the other hand [11] (Figures 6 and 7).

2.1.4. Building-Integrated Wind Turbines (BIWT)

Essential to building-integrated wind turbines is that architectural design is based on wind energy utilization. In other words, the concept of wind energy-effective design serves as the foundation. Building-integrated wind turbines, examined in two basic categories as building-mounted and building-unmounted, are turbines designed to be incorporated into the architectural design process, supported by the building's form, to alter or increase wind direction, speed, and intensity, with objectives toward maximizing the energy obtained [13].

2.2. Building-Integrated Active Energy Systems in Historic Buildings

History comprises events and situations from the past that remain in people's consciousness and affect the vast majority of people. A historic site/building/structure is the place where these events and situations occurred and the actual places that remain in people's minds. A cultural heritage's historical significance is understood according to certain qualities. These are clarified through questions such as: What is the age of the historic building (year of construction), is it a rarely found work, are there examples or if there are examples what distinguishing characteristics set them apart from others, are they spaces/places connected to the lives of famous people, and what is the relationship of these spaces to historic events [4].

The transformation of historic buildings by assigning them new functions and identities into structures capable of responding to contemporary technological and energy requirements is one of the theoretical and practical work areas supported by advanced nations' sustainable policies.

Beyond building repairs to provide energy gains in existing buildings, achieving energy gains in historic buildings is accepted in all societies that take pride in their cultural identity and desire sustainability of culture [4]. For this reason, renovation work conducted with integrated historic buildings using active energy system technologies to achieve energy gains and reduced CO2 emissions during historic building restoration processes is accelerating. The renewed structure not only preserves traditional material characteristics but also can provide conditions of less CO2 emissions and greater energy efficiency [4]. During the renewal of historic buildings with energy systems to achieve energy efficiency, in addition to system location-orientation decisions and architectural application decisions, material maintenance must be ensured throughout the approximately 25-year lifespan of the material [4].

2.2.1. Roof-Integrated Active Systems in Historic Buildings

Reichstag German Parliament Building Material: Heavy use of sandstone and granite stone materials. Location: 13:22 East Longitude, 52:31 North Latitude. Architecture: Resembles a linear single-nave church arrangement. The structure has four towers 46 m in height and building length of 137 m width. Energy Gains: The Reichstag Parliament Building was among important historic buildings in Germany before experiencing a fire. However, with its restoration, it is now referred to worldwide as both an important and exemplary building and is known as a low-energy, environmentally-friendly historic building. The Reichstag Building uses geothermal energy, natural ventilation, natural lighting, and active solar energy systems including building-integrated solar cells. Approximately 100 PV panels placed on the terrace roof surface provide approximately 40 kw of energy (Figures 8 and 9).

In Berlin, summers are very hot and winters very cold. In the 1960s, the fossil fuels used to both heat and cool the building signaled 7,000 tons of CO2 emissions.

Accordingly, biofuels were preferred over fossil fuels. This achieved annual CO2 emission measurements of 400 tons [14]. Dunster Castle Material: Bright red sandstone. Location: 3:26 West Longitude, 51:10 North Latitude. Architecture: Has a 1,000-year history. Constructed in 1066. Energy Gains: The energy renewal conducted with 24 PV panels on the terrace roof of Dunster Castle located near Minehead produces energy capable of meeting the daily energy consumption of two families. It prevents 3,000 kg of CO2 emissions annually. Carbon repatriation values reduce to "0" value within 4 years. Dunster Castle, with its transformation into an energy-efficient design, reduction in water consumption, recycling, and green transportation arrangements, becomes England's greenest castle. Photovoltaic panels configured with roof integration are installed at a minimum slope of 30 degrees. Considering the visual pollution that photovoltaic panels would create on the facade, roof-integrated PV systems are configured in the horizontal plane, particularly in non-visible areas. Dunster Castle is a good example where a solution has been found in response to energy needs (Figures 10-11) [15].

A Church in Mecklenburg-Vorpommern, Germany

The church roof was renewed with 88 monocrystalline module roof solar tiles. The carefully planned 50m2 PV roof system, with good planning, provides energy efficiency without casting shadows on module areas (Figures 12-13) [17]. Kynance Cove Cafe Material: No information found. Location: 5:13 West Longitude, 49:58 North Latitude. Architecture: No information found. Energy Gains: The cafe's roof tiles are specially made PV solar tiles. Each is a miniature solar panel. The Kynance Cafe energy renewal work represents the National Trust organization's first PV solar tile roof-integrated applications. A total of 564 solar tiles on the cafe and cottage roofs can produce more than 5,000 kwh annually and prevent 2,150 kg of CO2 emissions (Figures 14-15). Additionally, in the renewal work, 40% of water, plastic, glass, paper, and aluminum can waste was recycled, providing a gain of 19 trees from 1 ton of recycled paper, 32,000 liters of water, and 4,200 kwh of electricity, while 1.2 tons of raw materials and 150 liters of oil are gained from 1 ton of glass [18].

2.2.2. Facade-Integrated Active Systems in Historic Buildings

Ales Tourist Office, France Material: Stone material. Location: 4:4 East Longitude, 44:7 North Latitude. Architecture: Church remains constructed in the 11th century. The Ales city municipality wished to convert it into a tourist office. The building facade has a 3-arched bearing system, each approximately 6 m wide and 5 m in height (Figures 18-19). Energy Gains: An integrated PV design application was implemented in each arch opening. Double glazing with an 11 cm air gap applied behind the PV facade. The building is ventilated in summer through the air gap and heated in winter. Semi-transparent panels selected due to aesthetic concerns are coated with a brown anti-reflection coating. The facade-integrated PV panels positioned in the southeast direction with 100 m2 area can generate 9.6 kwp = 6,000 kwh of energy [21].

3. Conclusion

Regarding the 'energy' requirement, which is a 21st-century problem, implementations continue in many work areas in the name of a sustainable society. With knowledge of how much energy consumption buildings cause during their building life cycle, it has become impossible to exclude historic buildings, which are symbols of cultural identity, from the global energy problem during their building life cycle. Historic buildings are structures within the existing building stock that possess distinctive traditional materials, history, identity, and architectural characteristics and are restored by teams of subject matter experts. During restoration and subsequent renovation stages, energy gains can be achieved by utilizing renewable energy sources through building-integrated active systems suitable for the buildings' characteristic features, optimum comfort conditions, the climatic conditions that directed passive design at the time the historic building was constructed, and appropriate new functional spaces.

Passive design buildings are structures suitable to regional microclimatic conditions, considering passive design criteria, constructed with traditional materials, and with minimal CO2 emissions.

Heating and cooling systems added to these buildings later pollute the environment and increase CO2 emissions. Accordingly, renovation applications aimed at achieving energy gains, which is a new topic for historic buildings, represent another work area that will provide solutions to the era's energy crisis and the reduction of global warming. Building-integrated active energy systems that do not compromise historic buildings, can provide input to design in restoration decisions, and can be configured in integration alongside being installed on structures are currently being accepted in restoration work. Building-integrated active systems applied in historic buildings for energy gains have advantages as well as disadvantages during and after implementation. These are;

Advantages:

Social: a) Historic architectural heritage provides continuity of the community's cultural identity, uniting people with national solidarity sentiments. b) Enables interdisciplinary collaboration among archaeologists, engineers, art historians, and architects. c) Examples created generate demand among the public and raise user awareness. d) Contributes to urban planning and preservation of old historic urban fabric spatial composition. Economic: a) Does not have effects that increase building load. b) By ensuring continuity of building lifespan following repair, it prevents costly new building construction. Environmental: a) While the CO2 emission value of historic buildings constructed with traditional and natural materials is low, the application of building-integrated active system technologies to the structure will further reduce the CO2 emission level due to clean energy use. b) Building-integrated active system technologies enable us to achieve appropriate values in lighting, heating and cooling, indoor air quality, recyclable materials, and efficient energy use. Thus, healthy interior and exterior spaces can be created.

Disadvantages:

a) Design, material, and labor costs are high. b) Requires the design team to conduct more energy simulations and testing to achieve correct implementation results. c) There are no standards that can be adopted for all European and world countries. Each country must develop protection plans and renewal projects for its own cultural immovable heritage. d) It is not possible to make improvements to replace pieces that break or crack during the application of new technology to restored and renewed historic buildings. e) It is difficult to decide where to position the auxiliary equipment that operates the collector and solar cell systems so as not to create visual pollution on the building. Nilay Özeler Kanan / Senior Architect General Directorate of Professional Services / Energy Efficiency and Installation Department Directorate / Energy Efficiency Branch Management  

4. References

[1]. "Building Energy Efficiency" Attachment, Building Journal 2009/337 December, 6-7 [2]. https://biruni.tuik.gov.tr/yapiizin/giris.zul [3]. http://www.kulturvarliklari.gov.tr/belge/1-42957/tescilli-yapilar. html [4]. Ayçam, İ. and Özeler Kanan, N., "Renovation Applications Aimed at Achieving Energy Gains in Historic Buildings", International Sustainable Structures Symposium Proceedings Book, Ankara, Turkey, 289, (26-28 May 2010). [5]. Özeler Kanan, N., "The Use of Building-integrated Active Systems in Order to Provide Energy Gains in Historic Buildings", Ecocity 2009 Papers Book, Istanbul, Turkey, 306-318, (13-14-15 December 2009). [6]. http://www.wbdg.org/resources/bipv.php [7]. http://www.solarwatt.de/en/examples/commercial_customers/ [8]. http://www.samynandpartners.be/ [9]. http://www.heliopan.com.au/downloads_files/Heliopan_BIST_ Brochure.pdf [10]. http://www.solenza.co.nz/Solutions/bipvt.htm [11]. http://www.gunessistemleri.com/pvthibrit.php [12]. http://mediarelations.concordia.ca/pdf/Solar_PanelsENG.pdf [13]. http://www.emo.org.tr/ekler/975727c448e45ab_ek.pdf?dergi=4 [14]. http://www.fosterandpartners.com/content/essays/Reichstag%20 Energy%20Story.pdf [15]. http://www.nationaltrust.org.uk/main/w-energy-report-2010.pdf [16]. http://www.nationaltrust.org.uk/main/w-chl/w-countryside_ environment/w-climate_change/w-green_living/w-green_my_house/wgreen_my_house-trust/w-green_my_house-trust-case.htm#dunster [17]. http://www.pvresources.com/en/rooftile.php (http://www. pfleiderer-dach.de/) [18]. http://www.kynancecovecafe.co.uk/green.htm [19]. http://www.zukunft-haus.info/de/projekte/erneuerbare-energien/ beispiele-wohngebaeude/coswig-gartenstrasse.html [20]. New4Old work package 4.1 Technical guidelines for building designers, (January 2009). [21]. http://www.pvdatabase.org/projects_view_detailsmore. php?ID=126 [22]. http://www.tenesol.co.za/references/grid-public-sector-touristoffice-ales-france

Note: This study was prepared by developing the paper titled "Use of Roof and Facade Integrated Active Systems to Achieve Energy Gains in Historic Buildings" presented at the 6th Roof and Facade Symposium held on 12-13 April 2012 at Uludağ University, Görükle Campus, Bursa.