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Journal of Cultural Heritage 14S (2013) e25–e27

Available online at

www.sciencedirect.com

nergy incidence of historic building: Leaving no stone unturned

ristian Fabbri ∗

lma Mater Studiorum, University of Bologna, Bologna, Italy

a r t i c l e i n f o

rticle history:eceived 12 November 2012ccepted 2 December 2012vailable online 8 February 2013

eywords:nergy

a b s t r a c t

Energy and sustainability are a hard challenge in building heritage, both the technical solutions in order tosolve impact of energy conservation and aspect of conservation and maintenance of architectural heritage,and also the bigger target: sustainable development of human activity. The first issue is quantitative andmeasurable. The second issue is qualitative: what does sustainability of historic building mean? In someway historic building are the building that was preserved by past generation, which spend more economicand social resources, in order to maintain the ability of future generations to meet it. The energy saving

tatisticseritage buildingustainable developmentolicy makersnergy consumption of heritage buildingeritage building incidence

in historic building is a “new challenger” of research, but this may not able be a priority in order tosustainable development aims, if they are not to be subject to preservation of historic building.

© 2013 Elsevier Masson SAS. All rights reserved.

xergy

. Research aims

Energy and sustainability for heritage buildings: quantitativend qualitative approach. Energy incidence of heritage building intalian case. Indoor environmental quality and exergy index pro-osal.

. Experimental – Introduction

The debate about sustainable development, energy crisis andlso economy and financial crunch, concern several sector, includeduildings sector so architecture and heritage buildings.

In present paper, we would like to contribute to debate aboutnergy incidence in historic buildings. In the first place should belarifying the items of debate, focusing about three areas: heritageuildings, energy (or physic) discipline and sustainability.

‘Sustainable development’ has been defined at the end of 20thentury in 1987 at “World Commission on Environment andevelopment (WCED)” (Brundtland Commission) that defines it:

Sustainable development is development that meets the needs of

he present without compromising the ability of future generationso meet their own needs” [1]. Therefore sustainable developmentnclude the devolution of existing buildings, from past to futureenerations, and heritage buildings are result of these work.

∗ Faculty of Architecture, via Cavalcavia n. 55, 47023 Cesena, Italy.el.: +393397437328.

E-mail addresses: kristian.fabbri@unibo.it, kristian.fabbri@tiscali.it

296-2074/$ – see front matter © 2013 Elsevier Masson SAS. All rights reserved.ttp://dx.doi.org/10.1016/j.culher.2012.12.010

‘Restoration’ and also heritage building have been defined atthe end of 19th century following Ruskin and Violet Le Duc theo-ries. Maybe these could be considering a reaction against industrialrevolution, which it can change fast building, city and territory.

‘Energy’ has been discovered with fire in prehistoric age. Inaddition energy and architecture are linked during centuries withbraziers, fireplaces, stoves (from 16th–22nd century), also witharchitectural form and envelope energy performance. The energyconcept in physic discipline has been defined in 19th century byCarnot, Clausius, Kelvin, Joule and other scientists of the Thermo-dynamic. In the same period have been introduced technical plantsin buildings for heating and gas or electricity lighting.

3. Methodologies

The risks are to adopt a technical solution without “indicator”or “index”. According to quote “If you cannot measure it you can-not improve it” (Lord Kelvin) the indicators are a useful tools inorder to determinate level of tolerable (or intolerable) destructionor alteration of historic buildings. These indicators have to:

• suitable with architectural and urban contest;• adopt not only aim to get performance or energy index require-

ments, but others quality index (e.g. exergy);• evaluate kind of historical buildings follow local restoration dis-

cipline, for example the USA context is distinct compared toEuropean (UK, French, Italian, etc.) or other country (Turkey,etc.) contexts, numbers or incidence of heritage and historyknowledge.

e26 K. Fabbri / Journal of Cultural Heritage 14S (2013) e25–e27

Table 1Buildings and energy divided by theresold periods.

Period ISTAT ENEA (energy)

Total buildings foreach 10-day period

Numbers ofbuilding:progressive values

Percentageincidence

Increase by(10-day period)(%)

Total energy(ktoe)

Increase energy(ktoe) (%)

Toe/building

Before 1919 3,893,567 3,893,567 13.01 0.00From 1919 to 1945 2,704,969 6,598,536 22.05 40.99From 1946 to 1961 4,333,882 10,932,418 36.53 39.64From 1962 to 1971 5,707,383 16,639,801 55.60 34.30 20,334 0.00 1.22From 1972 to 1981 5,142,940 21,782,741 72.78 23.61 23,631 13.95 1.08From 1982 to 1991 3,324,794 25,107,535 83.89 13.24 27,337 13.56 1.09From 1991 to 2001 2,161,345 27,268,880 91.11 7.93 27,287 −0.18 1.00From 2001 to 2011 (estimate) 2,661,345 29,930,225 100.00 8.89 26,437 −3.22 0.88

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Total 29,930,225

Before to start restoration project (or research) as to improvenergy performance of heritage buildings, we think that “leavingo stone unturned”. The indicators will be improving in order toork out quantitative and qualitative issues.

.1. Quantitative issues

The first issue is quantitative and measurable: which is thenergy consumption incidence of historic buildings respect totaluilding?

The heritage building definition could be depending on culturalontext, but we can use three macro categories:

monument and building officially protected of their special archi-tectural or historical merit [2];buildings built before a historical date (historical threshold) e.g.before 20th century, or grassroots pre-industrial building [3];traditional or vernacular building like to represent specify archi-tectural, constructive and technology solutions [4–6].

In statistical analysis “historical thresholds” are a simple andey role. In Europe and Italy the main “historical thresholds” are918 (WWI) and 1945 (WWII). In “energy planning” and “energyerformance of buildings” studies using historic development so aso define envelope and construction technique or heating plantypologies and therefore they energy performance. In energyerformance analysis “historical thresholds” are more closed andfterwards WWII. The construction technique and building tech-ical plant technologies “historical thresholds” depend on culturalnd productive context. In USA air-conditioning has been introduceince 1930, in UK central heating plant are install in building since9th century with Perking with steam high pressure, whereas intaly central heating plant was introduced after 1950 and toilet inpartment after 1960. For example the history “historical thresh-lds” for heating plant are: in 22nd century has been introducedetal stove and fireplace flue improvement in building; in 19th

entury was introduced the industrial heating plant with boiler,adiators, etc.; in 20th century after 1945 a bigger increase of sev-ral heating, ventilation and air-conditioning plan typologies; ineventies of 20th century, due to 1973 energy crisis, has beenntroduced renewable plan (e.g. thermal solar); in seventies of 20thentury, was developed electronic control system; and a first yearsf 21st century has been introduced new plant: heating pump (HP)nd VRV/VRF plant, photovoltaic (PV), cogeneration heating powerCHP). We do not want to do a technical plant history, but just put

n evidence relations between restoration and technical plant tech-ologies thresholds. The building construction technologies havead same historical development, from brick masonry to reinforcedoncrete during 19th century, from pre-casting solution in fifteen

and seventeen to high-insulate and high performance enveloper ofpassive house at the turn of 21st century.

3.2. The Italian case–statistical data

In Italy “historical energy thresholds” could be determined bylaws adoption: Law 373/1976 define energy efficiency require-ments for heating plant; Law 10/1991 define maximum energyconsumption for new buildings; Law 192/2005 transpose DirectiveEPBD and define energy performance of buildings requirements.About this evolution is interesting to compare the buildings trend[7] and energy consumption of buildings trend [8]. How we cansee in tables the historical building incidence are the 13.01% forbuildings built before 1919 and only 22.05% of buildings were builtbefore 1945. Therefore the existing buildings before WWII are 1/5of all Real Estate market. The bigger incidence are existing buildingbuilt from 1945 to 1991 (61.84%) which have an energy consump-tion incidence greater than historic and new buildings. The energyconsumption of buildings trend, measured in toe/building (tonof oil equivalent for building), show a decrease of energy perfor-mance for single building between 1971 (1.22 toe/b) and 2011 (0.88toe/b.). If the aim is to reduce energy consumption the histori-cal buildings contribute is very little. The major benefit could beobtained with energy retrofit of existing building built after WWII(Tables 1 and 2).

4. Qualitative issues

The second issue is qualitative: what does sustainability of his-toric building mean? In some way, compared to Burtland’s reportdefinition of “sustainable”, the historic building are a building waspreserved by past generation, which spend more economic andsocial resources, in order to maintain the ability of future gen-erations to meet it. For the common good all have accepted tospend more burden and resources to conserve heritage building.The buildings energy consumption depend by four factors:

• destination use of building (dwelling, museum, office, library,etc.);

• occupancy pattern or real occupancy of building;• geometrical and thermo-physics of building envelope;• heating, ventilation and air-conditional performances.

All of these data input factors could be subject of change in

case of restoration project in order to reduce energy consump-tion. In heritage building restoration is possible to not to respectminimum energy requirements. So what are “indicators require-ments” of energy consumption to be taken into account? It should be

K. Fabbri / Journal of Cultural Heritage 14S (2013) e25–e27 e27

Table 2Energy divided by theresold periods.

Period ENEA (energy)

Energy – Progressive values (ktoe) Energy fluctuation (%) Energy fluctuation in ktoe/(10-day period)

Before 1919 4758* 0.00 4758From 1919 to 1945 11,369* 58.15 3305From 1946 to 1961 18,656* 39.06 5296From 1962 to 1971 20,334 8.25 6974From 1972 to 1981 23,631 13.95 3297From 1982 to 1991 27,337 13.56 3706From 1991 to 2001 27,287 −0.18 −50From 2001 to 2011* 26,437 −3.22 −850

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onsider energy use as a secondary effect. The “energy use” dependn several condition: microclimate, lighting level and other comfortndex. For these reasons the upon four factors should be changedn order:

to satisfy indoor comfort index (PMV or PPD), Indoor Environ-mental Quality categories [9];to maximize increase of “exergy” for same “energy use”, or ratherreduce of “exergy consumed”.

The exergy is an thermodynamic physical quantity defined how:«exergy» is the concept, which quantifies the potential of energy andatter to disperse in the course of their diffusion into their environment

nd «entropy» is the concept which quantifies the state of dispersion, tohat extent the energy and matter in question are dispersed” [10]. The

xergy is a concept nearly to restoration because contrast increasef entropy in energy process, like to restoration contrast increasef building deterioration.

. Methodology

The restorations of buildings need more resources: materialssets, economics and energy consumptions; that could be big-er than retrofit or new building, since they are heritage. Inase of heritage buildings the community is minded to acceptigher restrictions or cost for maintenance, for the common good:uilding conservation. The restoration is an example of theseextra-resources” that community decides to spend more for build-ng conservation. In the same way, from point of view of regionalnergy balance, the community may accept a higher energy con-umption for a small portion of existing buildings, if, in case ofestoration, the reduction of it energy consumption could involven unacceptable alteration. As a matter of fact the Directive EPBDnd EPBD recast not to apply the energy requirement “to buildingfficially protected as part of designated environment or because theirpecial architectural or historical merit” (EPBD recast article 4 comma

). The target in restoration historic cannot be energy Class A, or ahermal transmittance value, maybe could be an energy efficiencyncrease to satisfy thermal comfort. It follow that the aim cannot benly energy saving or energy minimum requirement by law (or by

[

26,437

energy labeling). The “indicators” must be related to energy, exergyand comfort indices.

6. Conclusion

The energy saving in historic building is a “new challenger” ofresearch, but this may not able be a priority in order to sustainabledevelopment aims, if they are not to be subject to preservation ofhistoric building. In some sense these issues are not only inside thearchitectural and restoration discipline, but they are also outside:in the real estate market, in urban planning and in energy policychoices.

About energy incidence of historic building the main sigh is“leaving no stone unturned” or rather do not adopt preconceptionsolutions only in order to obtain a specific energy label index.

References

[1] WCED 4 august 1987 (1987). Report of the World Commission on Envi-ronment and Development: “Our Common Future”: www.un-documents.net/a42-427.htm

[2] Directive 2010/31/UE (2010) of the European parliament and of the Council of19 may 2010 “on the energy performance of building (recast)” article 4 comma1 lett. (a).

[3] Ambrogio K. Ph.D. Thesis (2011) “Definizione dei fattori determinanti il com-portamento energetico e delle potenzialità d’intervento nel centro urbano diFerrara” (Definition of energy behaviours factor and retrofit opportunità in oldtown of Ferrara), University of Ferrara 2011.

[4] A. Oikonomou, F. Bougiatioti, Architectural structure and environmental per-formance of the traditional buildings in Florina, NW Greece, Build. Environ. 46(2011) 669–689.

[5] A.T. Nguyen, Q.B. Tran, D.Q. Tran, S. Reiter, An investigation on climate respon-sive design strategies of vernacular housing in Vietnam, Build. Environ. 46(2011) 2088–2106.

[6] Fabbri K., Tronchin L. Study of relation between clime, form and energy invernacular architecture in center of Italy. PLEA2006 – The 23rd Conference onPassive and Low Energy Architecture, Geneva, Switzerland, 6–8 September2006 (2006).

[7] ISTAT (2001) – Italian Population Census 2001: www.istat.it[8] ENEA (2007) – Italian National agency for new technologies, Energy and sus-

tainable economic development “Energy and Environmental Reports” 2001 and2007: www.enea.it

[9] EN 15251:2008 “Indoor environmental input parameters for design and assess-ment of energy performance of buildings addressing indoor air quality, thermalenvironment, lighting and acoustics”.

10] Shukuya M., Hammache A. “Introduction to the concept of exergy” VTT TIEDOT-TEITA Research Notes 2158. Submitted to IEA ANNEX 37 (2002) pp.10–14.