ENERGY EFFICIENCY IN HISTORIC BUILDINGS

Extended Abstract

Marta Alexandra Luís Gonçalves

Thesis to obtain the Master of Science Degree in

ARCHITECTURE

Supervisor: Professor Doutor José Maria da Cunha Rego Lobo de Carvalho

Examination Committee

Chairperson: Professora Doutora Helena Silva Barranha Gomes

Supervisor: Professor Doutor José Maria da Cunha Rego Lobo de Carvalho

Members of the Committee: Professor Doutor Manuel de Arriaga Brito Correia Guedes

October 2015

EXTENDED ABSTRACT

1

1. Energy efficiency in historic buildings. In Livia Tirone - Coberturas eficientes: guia para a reabilitação energético-ambiental do

edificado. Sintra: Tirone Nunes, SA (2011). By Élio Rocha.

ABSTRACT

Within the current energy paradigm, the sustainable revitalization of the

historical centres - limited and irreplaceable resources for their cultural, social and

economic value - through the warranty that the criteria of energy efficiency of

intervention in traditional buildings, constitute a essential and good component

regarding the urban rehabilitation. As a starting point, this dissertation addresses

the political and legislative framework in which the processes of urban rehabilitation

operates, trying to understand the balancing point between the current normative

demands and the intention to preserve the historical authenticity as well as the

material of the ancient buildings.

In this context, we used the systematic interpretation of case studies,

examining the actions that contributed to the decrease of energetic spending and

the improvement of comfort levels, in a way to evaluate the quality of the

interventions in the energy efficiency sector as a quality requisite provided in the

market of ancient buildings rehabilitation.

Based in the case studies and in good market practices, we can conclude

a set of solutions to attain a better energy efficiency in the ancient buildings, centred

in the rehabilitation of the exterior enclosure, evaluated hierarchally as its cost,

performance, sustainability and authenticity. In the current context of urban

rehabilitation, only by gaining conscience of the importance (and the quality) of the

energy efficiency in historical buildings that we can ensure a more sustainable

development, projecting the historical heritage for a future that is expected to be

more and more demanding regarding the environmental and energetic defense of

the built spaces.

KEYWORDS

Energy efficiency, Certification, Historic buildings, Urban rehabilitation.

2

2. Decarbonized grid power distribution. In Roadmap 2050: a pratical guide to a prosperous low carbon Europe. By AMO (Rem

Koolhaas).

Introductory Note:

It is considered an historical building,

one that was built up to 1940 with

historical technics and material, prior to

the arrival of concrete as a dominantly

structural material. In that context were

covered, at a typological level the

urban buildings “Pré-pombalinos”,

“Pombalinos” and “Gaioleiros”,

representatives of about half of all the

construction in Lisbon.

CONTEXT OF THE ENERGY EFFICIENCY IN THE CONSTRUCTION

THEORETICAL FRAMEWORK

After the Industrial Revolution, the development of news forms of energy

production allowed huge and rapid improvement of the living standards within the

modern societies. The economic growth was inseparable of the intense use of fossil

energy: finite and impactful, both in its exploration and in its consumption. The

succession of oil shocks that happened, along with the awareness that the planet

integrity was at stake, contributed to put the concept of energy efficiency on the

agenda, as a tool to reverse the energy dependency.

Thereby, the urgency to guarantee the energy efficiency to the building is a

fundamental contribution to reduce the environmental impact, because “a building

has a long life cycle, ergo its effect on the environment is a long and continuous

problem to consider”1. So, the energy efficiency within the Architecture is defined by

“intrinsic attribute to the building, representative of its potential in allowing thermal,

visual and acoustic comfort for users, with a low power consumption”2. With that in

mind, it is desirable that the cities management of the historical heritage is proactive

in terms of optimization of their energy-environmental performance. Obtaining the

compromise between the legal standards and the defence of the historical value of

the buildings is an exhaustive process, however it channels a position of knowledge

since, today, a rehabilitation that only respects the pre-existence is insufficient due

to comfort demands nowadays.

1 World Business Council for Sustainable Development - Eficiência energética em edifícios:

realidades empresariais e oportunidades. Lisboa: Conselho Empresarial para o

Desenvolvimento Sustentável (2007), p.6.

2 Fernando Pereira et al - Eficiência energética na Arquitectura. Rio de Janeiro: Programa

Nacional de Conservação de energia eléctrica (2013), p.5.

3

3. Political and legal evolution of energy

efficiency in historic buildings

rehabilitation. By author.

POLITICAL AND LEGAL FRAMEWORK

Due to the need to make some diligences, European policies were drawn

to lead to a integrated management of the energy resources. With the perspective

to generate a continuity of processes, the Europe Strategy 2020 (2010-2020) -

derived of the Lisbon Strategy (2000-2010) - defines the first big European energy

policy, the so called “20-20-20 Goal”, aiming the 20% reduction of greenhouse

gases, 20% of the energy coming from renewable sources and the increase of the

energy efficiency in 20%.

Being the common guidelines drawn in every member states, the success

of the goals depends, from now on, in the capacity of each country to execute

reforms through the formulation of the National Action Plans. Portugal resorts to the

National Plan of Action to the Energy Efficiency and the Energy Efficiency in the

Public Administration Program as a mean to make a balanced management in the

constructed buildings.

Until the implementation of the Lisbon Strategy, the energy efficiency in the

construction business was faced in a small holistic perspective in the context of the

legal instruments that were in place. The RCCTE (Regulation of the Building’s

Thermal Characteristics) operated according the proactive requirements to a more

efficient enclosure, while the RSECE (Regulation of the Energy Systems and

Building’s Acclimatization) acted in an independent way, in ensuring the

sustainability of air conditioning and ventilation systems.

After the launch of the first EPBD 2002/91/EC (European Directive to the

Building’s Energy Performance), the European Commission started a transversal

energy philosophy to be applied in all European buildings. In Portugal, the EPBD

would be transposed through the implementation of the National System of Energy

Certification and Indoor Air Quality, which, according to the RCCTE and RSECE

requirements, imposed the emission of energy certificates as a fundamental

instrument to the integrated pursuit of the energy demands in the buildings.

With the update on the EPBD 2010/31/EU the energy certification system is

modernized, it is now called Buildings Energy Certification System. In this process

the RCCTE and the RSECE were nullified and replaced by the REH (Regulation of

Energy Performance of Residential Buildings) and the RECS (Regulation of Energy

Performance of Trade and Services Buildings) where a efficient exterior enclosure is

aided by infrastructures desirably “feed” by renewable energy.

Lastly, outside the European recommendations, the RERU (Exceptional

Regime for Urban Regeneration) established an exception board to the revitalization

of the historical buildings – creating different rules that respected the inner root of

those buildings, making them affordable to all population – dispensing some of the

most important requirements regarding energy efficiency and thermal quality

imposed by the current REH and RECS.

4

From left to right: 4. Palacete dos Duques de Arévalo del Rey, Madrid. In http://www.mendarocorsini.es/# [6 Out. 2015]. 5. Centro

Cultural Daíoz y Velarde, Madrid. In Rafael de La-Hoz – Centro Cultural Daíoz y Velarde. Premios COAM - Categoría Rehabilitación

(2014), p.2.

6. Summary of energy rehabilitation

measures applied to international

historic buildings. By author.

CASE STUDIES

INTERNATIONAL BUILDINGS

Winners of the ASPRIMA-SIMA Award in the category of best initiative in the

energy rehabilitation, are considered to this analysis two buildings located in the

core of Madrid: the Palace of the Dukes of Arévalo del Rey and the Cultural Centre

Daíoz Y Velarde. Both portray the investigation context, being one of two types of

approach in the market of energy rehabilitation of traditional building, the

intervention based in renewable energy structures

In these constructions they installed a system fed by geothermal energy,

consisted in the soil perforation using probes. The detected energy (which the

temperature rises 3ºC by each 100 meters probed) is stored and after that, used to

acclimatize and produce hot sanitary waters. Regarding the energy distribution, this

system is based in a tridimensional thermal structure of slabs and pillars that

diffuses the temperature through radiant floors and a constant value of 20ºC.

As noted, to the implementation of this system was necessary to proceed

with a demolition of the entire interior matrix, formulating then, a façadism operation

to integrate the thermal structure. Regarding the exterior enclosure, one can say that

both examples did not accommodated considerable measures in the pursuit of

energy efficiency. Although some elements, like the windows, saw their energy

performance improved, the inexistency of measures applied mainly, to the façade,

confirm the rehabilitation character totally based in acclimatization processes and

not in passive strategies regarding comfort.

High levels of performance and energy sustainability are attained, however

there are some question marks regarding the destructive purpose of the authenticity

of the interior matrix and the costs involved to that effect.

5

From left to right: 7. Étoile 240, Lisboa. By author. 8. S. Tomé-Castelo, Lisboa. In http://www.archdaily.com/643663/hello-lisbon-castelo-

andre-espinho-arquitectura [6 Out. 2015]. By Giorgio Bordino. 9. Chalet das Três Esquinas, Braga. In

http://www.archdaily.com/451309/el-chale-de-las-tres-esquinas-tiago-do-vale-arquitectos [6 Out. 2015]. By João Morgado.

10. Summary of energy rehabilitation

measures applied to national historic

buildings. By author.

NATIONAL BUILDINGS

Winners of the National Prize for Urban Rehabilitation – in the category of

best solution to energy efficiency - we consider as well, for this analysis, two

buildings located in Lisbon: Étoile 240 and the S. Tomé-Castelo Building. A third

example is included, distinguished with several national and international awards in

the urban rehabilitation area: Chalet das Três Esquinas, erected in the heart of

Braga. They represent the second most used type of approach used in the energy

rehabilitation of buildings with relevant heritage value: the intervention base in the

exterior enclosure (roofs, façades and windows/doors).

The Étoile 240 represents rehabilitation with great value regarding the

energy intervention being extremely expensive. Being a façadism operation, all

exterior enclosure’s surfaces denote a total continuity in the application of thermal

insulation, allied to a frame systems with great efficiency.

The S. Tomé-Castelo Building reproduces a philosophy more based in

cost effectiveness and, therefore, more meaningful regarding the urban

rehabilitation market. Since the interior matrix was totally preserved and, having the

need to preserve the inside authenticity as well, the cost-performance relationship of

the application of thermal insulation in the totality of the exterior enclosure would not

be cost friendly, opting therefore for a more balanced management regarding this.

Lastly, the Chalet das Três Esquinas, appears as a defiance to all

intervention logic used beforehand. Apart from the methodology or the degree of

the attained efficiency, all intervention have the need to apply the principles of

energy efficiency, even if the buildings that are sensitive to their heritage value. This

intervention only had impact in the aesthetical rehabilitation and functional of the

building, not incorporating a significant measure to improve the exterior enclosure.

One can question the fact that it still is possible, nowadays, to operate under a

perspective that is totally off regarding sustainability used nowadays.

6

From left to right: 11. Roof insulation. By Marianne Suhr. 12. Façade regularization. By Ralph Hodgson. 13. Secondary glazing. By Roger

Hunt. In Society for the Protection of Ancient Buildings - Briefing: Energy Efficiency in Old Buildings. London (2014), pp.7-15.

ENERGY EFFICIENCY IN HISTORIC BUILDINGS

Regarding the recommendations to the energy rehabilitation of historical

buildings – with economic viability and practice within the market reality – it was

necessary to deeply understand the logics of old architecture. A big part of the

discussion regarding the energy efficiency is dependant of the performance of this

traditional exterior enclosure, which, as a rule, reaches already a good

responsiveness to summer comfort needs but a poor response to winter conditions.

Acting with the purpose to boost improvements, having in mind the limitations of

this building as environmental system, objectifying a qualitative preservation urging

longevity and performance standards induction quite like a new building.

Therefore, an ancient roof, is, side by side with window systems, the

element that distances itself apart from the regulation used in our days. As a rule,

their advanced state of deterioration makes it unfeasible - economically, security

and structural strength - its revitalization, opting for total reconstruction with

improved levels of thermal insulation.

Unlike the roofs, the old building façades are closer to fulfil the

performance demands that are required nowadays, due to his high thickness

allowing a slow thermal transfer between the interior and exterior. This condition can

be easily improved with the introduction of thermal insulation, according to the

breathability of the tissue and the authentic demands allow it.

Lastly, the windows systems configure themselves as a element where the

disparity between the energy performance of ancient solutions and the ones used

nowadays are bigger. It’s, as a tendency, the element of exterior enclosure more

sacrificed in the rehabilitation actions, being the most used solution, the

replacement of old systems with ones much more efficient.

7

14. Summary of energy rehabilitation

measures to be applied in envelope of

historic buildings. (1) Best solution – (4)

Worst solution. By author.

8

15. Maluda - “Castelo de vide”. Óleo sobre tela 90 cm x 90 cm (1971), colecção Fundação Calouste Gulbenkian.

FINAL CONSIDERATIONS

It is evident a comprehension of the energy efficiency in the current

rehabilitation practices of the historical heritage is needed - in the light of political

precepts, of the mandatory regulations and the level of receptivity/conscience of the

market - acquiring a position of firm and wide knowledge, that allows to establish

some criticism and recommendations with a real range.

Having in mind legislation, that is, today, fragmented and disjointed, a

misinformation is intensified when the time comes to rehabilitate with quality

fundamentals. The nonexistence of a unified document to rehabilitate the historical

centres that focus with clarity the importance of a methodology aimed towards the

energetic efficiency, a big part of the interventions opt for the easiest and simplest

path: use of the exception schemes, avoiding having to answer the demands of the

energy efficiency. This urgency in establishing more obligations arises since the

financial interests are prioritized instead of the quality of the interventions, noting in

the future that these exact interventions were based in pillars that were

environmentally unsustainable. The rehabilitations is predominately executed having

only in mind short term benefits – like the aesthetics and the functionality – but rarely

with an approach based on the energy preservation or in the decrease of energy

consumption throughout the building’s life cycle.

Throughout the history of architecture, the building’s energy efficiency was

determined by the exterior enclosure’s constitution. Is in possible that in the future

that constitution will show itself sufficient to answer the growing demands in terms

of regulation and comfort? Is that with the gradual introduction of renewable energy

in air conditioning and ventilation systems, won’t be them that manage the buildings

energetically wise? We live in a time of turning the metabolic behaviour of the cities,

whose renewal of energy model will certainly and in short term changes to the very

paradigm of urban regeneration and to the conditions of historical area.