Skip to main content

Advertisement

SpringerLink
Log in

A sensitivity analysis of a cost optimality study on the energy retrofit of a single-family reference building in Portugal

  • Original Article
  • Published:
Energy Efficiency Aims and scope Submit manuscript

Abstract

Improvement of the energy efficiency of residential buildings must ensure compliance with cost optimality criteria, assuming a specific lifespan of the building. At the same time, the energy retrofit of buildings ought to preserve their intrinsic architectural and heritage value. Portuguese residential buildings constructed before 1960 did not follow any energy efficiency rules. They represent 29% of the housing stock in the country and there is a high potential for increasing their energy efficiency. However, it costs more to implement envelope energy efficiency measures through retrofitting works than to provide for them in new buildings. An evaluation based on cost optimality criteria should therefore be performed. This work evaluates the energy performance of a Portuguese reference building typical of the pre-1960 building stock for different thicknesses of thermal insulation retrofit solutions (roof, facade, and ground floor) and systems. The study describes a sensitivity analysis that took a range of climate data, intervention costs, energy prices, discount rates, and energy needs into account. An energy needs factor dealt with the occupants’ habits and the effective reduction of energy consumption compared with the estimated energy needs.

This is a preview of subscription content, log in via an institution to check access.

Access this article

Log in via an institution

Price excludes VAT (USA)
Tax calculation will be finalised during checkout.

Instant access to the full article PDF.

Fig. 1
Fig. 2
Fig. 3
Fig. 4
Fig. 5
Fig. 6
Fig. 7
Fig. 8
Fig. 9
Fig. 10
Fig. 11

Similar content being viewed by others

Notes

  1. APCMC—Associação Portuguesa dos Comerciantes de Materiais de Construção; APIRAC—Associação Portuguesa da Indústria da Refrigeração e Ar Condicionado

  2. CYPE—Software for Architecture, Engineering and Construction

Abbreviations

AC:

air conditioner

DGEG:

General Directorate for Energy and Geology

DHW:

domestic hot water

ECS:

Energy Certification System

EH:

electric heater

EPBD:

Energy Performance in Buildings Directive

EPCs:

energy performance certificates

EPS:

expanded polystyrene

EU:

European Union

FIN:

financial perspective

GB:

gas boiler

GW:

glass fiber

GWH:

gas water heater

HDD:

heating degree days [°C day]

HP:

heat pump

ICB:

expanded cork board

ICB-MD:

expanded cork board (medium density)

ICESD:

Survey on Energy Consumption in the Domestic Sector

INE:

National Statistics Institute

MAC:

macroeconomic perspective

MW:

mineral wool

NPV:

net present value

PE:

primary energy

PEF:

primary energy conversion factor

PUR:

polyurethane foam

VAT:

value-added tax

XPS:

extruded polystyrene

ψ:

linear thermal transmittance [W/m°C]

C i, j :

annual costs [€]

D i :

discount factor

E h, k :

heating energy needs [kWh/(m2 year)]

E w, k :

domestic hot water energy production [kWh/(m2 year)]

F s, j :

glazing obstruction factor associated with the orientation j

GHG i, j :

carbon emission cost [€]

G s :

monthly solar energy on a south vertical surface [kWh/(m2 month)]

H ecs :

heat loss to elements in contact with the ground [W/°C]

H enu :

heat loss to unheated spaces and to adjacent buildings [W/°C]

H ext :

heat loss to the outside [W/°C]

H tr, i :

overall transmission coefficient of heat transfer [W/°C]

H ve, i :

overall coefficient of heat transfer from ventilation [W/°C]

I j :

initial investment costs [€]

K :

number of systems

P :

conversion factor between final energy and primary energy

P d :

height of ceilings [m]

Q int, i :

internal solar gains [kWh/year]

Q sol, i :

glazing solar gains [kWh/year]

Q tr, i :

heat transfer coefficient by transmission [kWh/year]

Q ve, i :

heat transfer coefficient by ventilation [kWh/year]

R ph :

nominal rate of renewal of indoor air in the heating season [h−1]

V τ, j :

residual value associated with each measure [€]

a H :

function of thermal inertia of the building class [W/°C]

f h, k :

percentage of the energy needs for space heating [%]

f w, k :

percentage of the energy needs DHW [%]

q int :

average internal thermal gain per area [W/m2]

η H, gn :

gain utilization factor

η :

efficiency

A:

area [m2]

CO2 :

carbon dioxide

gw :

solar factor of the glazing

r :

thermal resistance [(m2 °C)/W]

U:

thermal transmittance [W/(m2 °C)]

X:

orientation factor

G(τ):

global cost [€]

M :

duration of the heating season [months]

NM :

number of measures

R :

real discount rate [%]

e :

thickness [m]

λ :

thermal conductivity [W/(m °C)]

τ :

calculation period [years]

e:

vertical opaque envelope

f:

floor

h :

space heating

max:

maximum requirement

optimum:

cost-optimal solution

r:

roof

ref.:

reference

w:

windows

j :

corresponds to the each orientation

k :

single energy source/system

w :

domestic hot water

References

  • Buildings Performance Institute Europe (2011). Europe’s buildings under the microscope.

  • National Statistics Institute (2011). Inquérito ao Consumo de Energia no Sector Doméstico - 2010, Directorate General for Energy and Geology, Portugal (in Portuguese).

  • United Nations Environment Programme (2007). Buildings and climate change.

  • Portuguese Ministry of Environment (2014). Territorial Planning and Energy, Decree-Law no.53/2014 of 8 April, Regulamento de Desempenho Energético dos Edifícios de Habitação (REH) Diário da República (in Portuguese).

  • Boeck, L., Verbeke, S., Audenart, A., & Mesmaeker, L. (2001). Improving the energy performance of residential buildings: a literature review. Renewable and Sustainable Energy Reviews, 52, 960–975.

    Article  Google Scholar 

  • European Commision (2010). Directive 2010/31/EU. Energy Performance of Building Directive.

  • European Commision (2012). Commission Delegated Regulation (EU) No. 244/12.

  • Baglivo, C., Congedo, P. M., D’Agostino, D., & Zacà, I. (2015). Cost-optimal analysis and technical comparison between standard and high efficient mono-residential buildings in a warm climate. Energy, 83, 560–575.

    Article  Google Scholar 

  • Kurnitsk, J., Saari, A., Kalamees, T., Vuolle, M., Niemela, J., & Tark, T. (2011). Cost optimal and nearly zero (nZEB) energy performance calculations for residential buildings with REHVA definition for nZEB national implementation. Energy and Buildings, 43, 3279–3288.

    Article  Google Scholar 

  • Vasconcelos, A., Pinheiro, M., Manso, A., & Cabaço, A. (2016). EPBD cost-optimal methodology: application to the thermal rehabilitation of the building envelope of a Portuguese residential reference building. Energy and Buildings, 111, 12–25.

    Article  Google Scholar 

  • Corgnati, S. P., Fabrizio, E., Filippi, M., & Monetti, V. (2013). Reference buildings for cost optimal analysis: method of definition and application. Applied Energy, 102, 983–993.

    Article  Google Scholar 

  • Loga, T., Diefenbach, N., Stein, B., Balaras, C. A., Villatoro, O. & Wittchen, K. B. (2012). Typology approach for building stock energy assessment. Main Results of the TABULA project, Institut Wohnen und Umwelt GmbH.

  • INIVE EEIG. (2010). Stimulating increased energy efficiency and better building ventilation. In Brussels.

    Google Scholar 

  • Bessa, V. M. T., & Prado, R. T. A. (2015). Reduction of carbon dioxide emissions by solar water heating systems and passive technologies in social housing. Energy Policy, 83, 138–150.

    Article  Google Scholar 

  • Jelle, B. P. (2011). Traditional, state-of-the-art and future thermal building insulation materials and solutions—properties, requirements and possibilities. Energy and Buildings, 43(10), 2549–2563.

    Article  Google Scholar 

  • Hamdy, M., Hasan, A., & Siren, K. (2013). A multi-stage optimization method for cost-optimal and nearly-zero-energy building solutions in line with the EPBD-recast 2010. Energy and Buildings, 56, 189–203.

    Article  Google Scholar 

  • Tadeu, S., Simões, N., Gonçalves, M., & Ribeiro, J. (2013). Energy efficiency measures in Portuguese residential buildings constructed before 1960: a cost-optimal assessment, Energy for sustainability 2013—sustainable cities: designing for people and the planet.

  • Kaynakli, O. (2012). A review of the economical and optimum thermal insulation thickness for building applications. Renewable & Sustainable Energy Reviews, 16(1), 415–425.

    Article  Google Scholar 

  • Sisman, N., Kahya, E., Aras, N., & Aras, H. (2007). Determination of optimum insulation thicknesses of the external walls and roof (ceiling) for Turkey’s different degree-day regions. Energy Policy, 35(10), 5151–5155.

    Article  Google Scholar 

  • Axaopoulos, I., Axaopoulos, P. & Gelegenis, J. (2014). Optimum insulation thickness for external walls on different orientations considering the speed and direction of the wind, Applied. Energy, 117, 167–175.

  • Tadeu, S., Rodrigues, C., Tadeu, A., Freire, F., & Simões, N. (2015). Energy retrofit of historic buildings: environmental assessment of cost-optimal solutions. Journal of Building Engineering, 4, 167–176.

    Article  Google Scholar 

  • Verbeeck, G., & Hens, H. (2005). Energy savings in retrofitted dwellings: economically viable? Energy and Buildings, 37(7), 747–754.

    Article  Google Scholar 

  • Nikolaidis, Y., Pilavachi, P. A., & Chletsis, A. (2009). Economic evaluation of energy saving measures in a common type of Greek building. Applied Energy, 86(12), 2550–2559.

    Article  Google Scholar 

  • Panão, M. J. N. O., Rebelo, M. P., & Camelo, S. M. L. (2013). How low should be the energy required by a nearly zero-energy building? The load/generation energy balance of Mediterranean housing, energy and buildings, 61, 161–171.

    Google Scholar 

  • Malatji, E. M., Zhang, J., & Xia, X. (2013). A multiple objective optimization model for building energy efficiency investment decision. Energy and Buildings, 61, 81–87.

    Article  Google Scholar 

  • Ferrara, M., Fabrizio, E., Virgone, J., & Filippi, M. (2014). A simulation-based optimization method for cost-optimal analysis of nearly zero energy buildings. Energy and Buildings, 84, 442–457.

    Article  Google Scholar 

  • Tadeu, S., Alexandre, R. F., Tadeu, A., Antunes, C. H., & Simões, N. (2016). A comparison between cost optimality and return on investment for energy retrofit in buildings—a real options perspective. Sustainable Cities and Society, 21, 12–25.

    Article  Google Scholar 

  • Asadi, E., Silva, M. G., Antunes, C. H., & Dias, L. (2012). Multi-objective optimization for building retrofit strategies: a model and an application. Energy and Buildings, 44, 81–87.

    Article  Google Scholar 

  • Brealey, R. A., Myers, S. C. & Marcus, A. J. (2001). Fundamentals of corporate finance, Third Edn. University of Phoenix.

  • Ferreira, M., Almeida, M., Rodrigues, A., & Monteiro Silva, S. (2014). Comparing cost-optimal and net-zero energy targets in building retrofit. Building Research & Information. https://doi.org/10.1080/09613218.2014.975412.

  • Zacà, I., D’Agostino, D., Congedo, P. M., & Baglivo, C. (2015). Assessment of cost-optimality and technical solutions in high performance multi-residential buildings in the Mediterranean area. Energy and Buildings, 102, 250–265.

    Article  Google Scholar 

  • Zanghari, P., Armani, R., Pietrobon, M., & Pagliano, L. (2017). Identification of cost-optimal and NZEB refurbishment levels for representative climates and building typologies across Europe. Energy Efficiency, 11, 337–369.

    Article  Google Scholar 

  • Kumbaroğlu, G., & Madlener, R. (2012). Evaluation of economically optimal retrofit investment options for energy savings in buildings. Energy and Buildings, 49, 327–334.

    Article  Google Scholar 

  • European Committee for Standardization (2008). ISO 13790, Energy performance of buildings—calculation of energy use for space heating and cooling.

  • Portuguese Ministry of Construction (1990). Transports and Communications, Decree-Law no.40/90 of 6 April, Regulamento das Características de Comportamento Térmico dos Edifícios, RCCTE. Diário da República (in Portuguese).

  • Vasconcelos, A., Pinheiro, M., Manso, A., & Cabaço, A. (2015). A Portuguese approach to define reference buildings for cost-optimal methodologies. Applied Energy, 140, 316–328.

    Article  Google Scholar 

  • Bragança, L., Wetzel, C. & Buhagiar, V. (2007). COST C16—improving the quality of existing urban building envelopes—facades and roofs. IOS Press.

  • ADENE (2014). Portal SCE - Sistema Certificação Energética dos Edifícios. www.adene.pt/sce (acessed 2014).

  • Serra, C., Simões, N., Tadeu, S. & Tadeu, A. (2013). Definition of reference buildings for energy performance calculation—Portuguese case, Energy for sustainability 2013—sustainable cities: designing for people and the planet.

    Google Scholar 

  • Portuguese Ministry of Economy and Employment (2013). Decree-Law no.118/2013 of 20 August, Diário da República, (in Portuguese).

  • Internacional Energy Agency (2013), Modernising building energy codes.

  • Ferreira, M., Almeida, M., & Rodrigues, A. (2013). Cost optimality and nZEB target in the renovation of Portuguese building stock—Rainha Dina Leonor neighborhood case study. Sustainable Building Conference SB13 Proceedings, 3542.

  • European Comission (2013). EU Energy, transport and GHG emissions: trends to 2050, Reference Scenario 2013.

  • Energy Services Regulatory Authority (2015). Reference prices in the liberalized market of electricity and natural gas in continental Portugal (in Portuguese).

  • Caixa Geral de Depósitos (2015), Credit for rehabilitation (in Portuguese).

  • Sunikka-Blank, M., & Galvin, R. (2012). Introducing the pre-bound effect: the gap between performance and actual energy consumption. Building Research & Information, 40(3), 260–273.

    Article  Google Scholar 

  • European Committee for Standardization (2007). EN 15459. Energy performance of buildings—economic evaluation procedure for energy systems in buildings.

  • CYPE Ingenieros, S. A. (2013). Gerador de preços para construção civil, http://www.geradordeprecos.info/ (accessed 2013) (in Portuguese).

  • ECOFYS (2007). U-values—for better energy performance of buildings, European Insulation Manufactures Association.

  • Portuguese Ministry of Environment (2015). Territorial Planning and Energy, Order no.379-A/2015 of 22 October, Diário da República (in Portuguese).

  • Eurostat (2013). Electricity and natural gas price statistics—statistics explained, http://epp.eurostat.ec.europa.eu/statistics_explained/index.php/Electricity_and_natural_gas_price_statistics (accessed 2013).

Download references

Funding

The first author is grateful for the financial support provided by the Ciência sem Fronteiras program and acknowledges the support of Conselho Nacional de Desenvolvimento Científico e Tecnológico through doctoral degree grant 237489/2012-0 and Fundação de Amparo à Pesquisa do Estado de São Paulo through grant PIPE—2016/00880-9 (Brazil). This research work has also been supported by the Operational Programme for Competitiveness and Internationalization (COMPETE 2020, Portugal 2020), through the European Regional Development Fund under research project POCI-01-0247-FEDER-003408 (Slimframe PV & Cork Skin).

Author information

Authors and Affiliations

  1. Department of Civil Engineering Construction (PCC) – Escola Politécnica, University of São Paulo, Tr. 2 no. 83 – Cidade Universitária, São Paulo, 05508-900, Brazil

    Sérgio Tadeu & Racine Prado

  2. ITeCons - Institute for Research and Technological Development in Construction Sciences, Rua Pedro Hispano s/n, 3030-289, Coimbra, Portugal

    Sérgio Tadeu, António Tadeu, Nuno Simões & Márcio Gonçalves

  3. ADAI – LAETA, Department of Civil Engineering, FCTUC, University of Coimbra, Pólo II, Rua Luís Reis Santos, 3030-788, Coimbra, Portugal

    António Tadeu & Nuno Simões

Authors
  1. Sérgio Tadeu
    View author publications

    You can also search for this author in PubMed Google Scholar

  2. António Tadeu
    View author publications

    You can also search for this author in PubMed Google Scholar

  3. Nuno Simões
    View author publications

    You can also search for this author in PubMed Google Scholar

  4. Márcio Gonçalves
    View author publications

    You can also search for this author in PubMed Google Scholar

  5. Racine Prado
    View author publications

    You can also search for this author in PubMed Google Scholar

Corresponding author

Correspondence to Sérgio Tadeu.

Ethics declarations

Conflict of interest

The authors declare that they have no conflict of interest.

Rights and permissions

Reprints and permissions

About this article

Check for updates. Verify currency and authenticity via CrossMark

Cite this article

Tadeu, S., Tadeu, A., Simões, N. et al. A sensitivity analysis of a cost optimality study on the energy retrofit of a single-family reference building in Portugal. Energy Efficiency 11, 1411–1432 (2018). https://doi.org/10.1007/s12053-018-9645-5

Download citation

  • Received:

  • Accepted:

  • Published:

  • Issue Date:

  • DOI: https://doi.org/10.1007/s12053-018-9645-5

Keywords

Search

Navigation