XI World Congress of the Organization of World Heritage Cities

Sintra (Portugal), 22 – 25 November 2011

World Heritage Cities and Climate Change

Oporto traditional buildings sustainable refurbishment

traditional buildings energy performance

(jflores@brookes.ac.uk) FLORES, Joaquim/ Portugal

BACKGROUND

- Greenhouse gas (GHG) emissions are one of the most important causes of Climate change

(IPCC, 2007)

- CO2 is the most relevant gas contributing to GHC emissions (IPCC, 2007)

- Power generation and consumption from fossil fuel are the major CO2 emissions contributor

(EEA, 2011)

- Buildings are responsible for more than 40% of global energy use and approximately one

third of global GHG emissions (Metz and IPCC, 2007; UNEP, 2010)

Refurbishment of traditional buildings in World Heritage Cities poses a triple opportunity:

- Potential improvement of environmental performance by CO2 emissions reduction trough

energy efficiency;

- Conservation and recycling of a built resource contributing locally to global environmental,

economic and social sustainable development;

-Preservation of centennial built heritage whose management of change must carefully

balance the previous questions with their relevant cultural significance.

RESEARCH AREA and TRADITIONAL BUILDING TYPOLOGY

- A study area was delimited corresponding to the «Infante Priority Intervention Area» of

Oporto Urban Rehabilitation Society «Porto Vivo».

- Located in the core of World Heritage area and in the administrative unit of «Freguesia de

São Nicolau», with 319 buildings in 17 blocks spread for 0,097 Km2.

-From the field survey was possible to describe the traditional buildings typology as mainly

residential (with shops on ground floor), narrow and long lot, terraced houses facing the

street, hip roof, 3 to 5 floors, 2 or 3 opening rows per floor, solid granite exterior walls, inner

wood structure, plaster or tiles in the main facade, simple glazed wood windows, interior

wood shutters, central stairs with above skylight providing natural light and ventilation.

VARIANTS

From this typology, 6 main variants were identified, accordingly to their urban insertion

FURTHER RESEARCH

This PhD research project is been conducted in the Department of Architecture – Oxford Brookes University with the supervisory team of Dr. Aylin Orbasli and Professor Rajat Gupta.

The 10 case studies are been modeled for energy simulation in order to determine which are the most effective and feasible measures (refurbishment and behavior change).

Variant 1 Scheme and 3D schematic model Variant 2 Scheme and 3D schematic model

Variant 3a Scheme and 3D schematic model Variant 3b Scheme and 3D schematic model

Variant 4 Scheme and 3D schematic model Variant 5 Scheme and 3D schematic model

Traditional Typology – Section, ground floor and upper

floors (base drawing from CRUARB Survey – Oporto

Historic Archive)

Variant Buildings %

V1 34 10,66

V2 33 10,34

V3a 77 24,14

V3b 121 37,93

V4 51 15,99

V5 3 0,94

Variant Observ Building Age

Butane Gas

Consumption

(Kwh/year)

Electricity

Consumption

(Kwh/year)

Total energy

Consumption

(Kwh/year)

HouseholdsHouse area

(m2)

Dwelling

Floors

Kwh/m2

year

KWh/person

year

V1 Mid. floor before XVIII 0 2605,74 2605,74 2 37,14 1 70,16 1302,87

V1 Top floor XIX 1092 3421,76 4513,76 1 118,94 2 37,95 4513,76

V2 Mid. floor XVIII 1456 1796,81 3252,81 2 20,66 1 157,44 1626,41

V2 Top floor XIX 3276 804,13 4080,13 5 25,20 1 161,91 816,03

V3a Mid. floor XVIII 2184 4139,04 6323,04 3 78,15 1 80,91 2107,68

V3a Top floor XVIII 3276 2950,27 6226,27 4 76,10 2 81,82 1556,57

V3b Mid. floor XIX 2184 3641,97 5825,97 5 62,78 1 92,80 1165,19

V3b Top floor XVIII 1092 5978,26 7070,26 6 95,05 2 74,38 1178,38

V4 Mid. floor XIX 2184 5692,66 7876,66 4 45,74 1 172,21 1969,17

V4 Top floor XIX 873,6 3896,90 4770,50 4 81,77 1 58,34 1192,62

CASE STUDIES

- 10 buildings direct survey (2 for each relevant variant) was undertake to

evaluate real energy consumptions and concrete households behaviour.

DRAFT CONCLUSIONS

- The most common building variants (V3a and V3b) which have most

favourable urban insertion and form factor, revealed in the survey to have

average consumptions under the average of BPIE study (200 to 110 Kwh/m2)

(BPIE, 2011)

- As referred in the recent study to promote thermal upgrade in Oporto

traditional buildings (AdEPorto et al., 2010), the heritage constraints directs

mainly the measures to roof and gable facades insulation and improvement of

windows frames.

- From the direct survey was possible to conclude that the most feasible

measures to be promoted in these typical residential buildings reside in

changing household’s behaviour and improving to more efficient appliances.

- Other type of measures are more difficult to apply due to social and Legal

constraints: most of the households is low income and live in rented house

paying low rents, which reduces the possibility of refurbishment, both by

tenants and homeowners.

ReferencesAdEPorto et al(2010). Reabilitação de Edifícios do Centro Histórico do Porto - Guia de Termos de Referência para o Desempenho Energético-Ambiental. Oporto: PORTO VIVO – SRU; BPIE (2011). Europe’s buildings under the

microscope : A country-by-country review of the energy performance of buildings. Brussels: BPIE, Buildings Performance Institute Europe; EEA, (2011). Greenhouse gas emission trends and projections in Europe 2011 : Tracking

progress towards Kyoto and 2020 targets. EEA Report. Copenhagen: EEA, IPCC (2007). Climate Change 2007: Synthesis Report. Geneva: IPCC; Metz, B. and IPCC (2007). Climate change 2007 : mitigation of climate change.

Cambridge: Cambridge University Press; UNEP (2010). Climate Friendly Buildings and Offices : A Practical Guide. Paris: UNEP, United Nations Environment Programme.