Skip to main content
SpringerLink
Log in

Numerical simulation of heat transfer in a roof assembly with reflective insulation and radiant barrier

  • Research Article
  • Indoor/Outdoor Airflow and Air Quality
  • Published:
Building Simulation Aims and scope Submit manuscript

Abstract

The increasing demand of reducing energy consumption in buildings has led to the implementation of insulation material in roof assemblies to reduce heat gain through the roof. This paper investigates the thermal performance of reflective insulation and radiant barrier systems in a gable roof assembly by using computational fluid dynamics (CFD) simulation. In the first part of the paper, the experimental measurements using test huts under actual outdoor environment were detailed. The CFD simulation was then conducted and the results obtained from the simulation were validated against the experimental measurements. In the second part paper, the validated CFD model was then used to evaluate the reduction of heat flux transmission through the roof and the thermal resistance (RSI value) of the roof assemblies for various roof configurations, which are the thickness of reflective air space, the roof pitch and the roof material. The study showed that increasing the reflective air space thickness from 25 mm to 100 mm has increased the total RSI by 26% for both roof pitch of 30° and 45°. Besides that, increasing the roof pitch of the roof from 30° to 45° showed that biggest impact on the thermal performance of the roof, as the RSI value increases by 30%. In terms of roof tiles material, only small difference was observed in terms of thermal resistivity when switching the roof tiles material between clay tiles and concrete tiles.

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.

Institutional subscriptions

Similar content being viewed by others

Abbreviations

c :

specific heat capacity (J/(K·kg))

E :

emissivity

g i :

gravitational acceleration component along the i-th coordinate direction (m/s2)

h :

thermal enthalpy (J)

N :

number of fitted points

QH:

heat source of sink per unit volume (W)

q i :

diffusing heat flux (W/m2)

S i :

mass-distributed external force per unit mass

t :

thickness of reflective air space (mm)

u :

fluid velocity (m/s)

τij :

viscous shear stress tensor (Pa)

λ:

thermal conductivity (W/m·K)

ρ:

density (kg/m3)

3D:

three dimensional

CFD:

computational fluid dynamics

MAPE:

mean absolute percentage error

RSI:

thermal resistance

SERI:

Solar Energy Research Institute

UKM:

National University of Malaysia

References

  • Alzwayi AS, Paul MC (2014). Transition of free convection flow inside an inclined parallel walled channel: Effects of inclination angle and width of the chan nel. International Journal of Heat and Mass Transfer, 68: 194–202.

    Article  Google Scholar 

  • Department of Standards Malaysia (2014). Energy Efficiency and Use of Renewable Energy for Residential Buildings—Code of Practice (MS 1525:2014).

  • Dimoudi A, Androutsopoulos A, Lykoudis S (2006). Summer performance of a ventilated roof component. Energy and Buildings, 38: 610–617.

    Article  Google Scholar 

  • Fantucci S, Serra V (2019). Investigating the performance of reflective insulation and low emissivity paints for the energy retrofit of roof attics. Energy and Buildings, 182: 300–310.

    Article  Google Scholar 

  • Gagliano A, Patania F, Nocera F, Ferlito A, Galesi A (2012). Thermal performance of ventilated roofs during summer period. Energy and Buildings, 49: 611–618.

    Article  Google Scholar 

  • Hernández-Pérez I, Álvarez G, Xamán J, Zavala-Guillén I, Arce J, Simá E (2014). Thermal performance of reflective materials applied to exterior building components—A review. Energy and Buildings, 80: 81–105.

    Article  Google Scholar 

  • Lee SW, Lim CH, Salleh EIB (2016). Reflective thermal insulation systems in building: a review on radiant barrier and reflective insulation. Renewable and Sustainable Energy Reviews, 65: 643–661.

    Article  Google Scholar 

  • Lee S, Park SH, Yeo MS, Kim KW (2009). An experimental study on airflow in the cavity of a ventilated roof. Building and Environment, 44: 1431–1439.

    Article  Google Scholar 

  • Li D, Zheng Y, Liu C, Qi H, Liu X (2016). Numerical analysis on thermal performance of naturally ventilated roofs with different influencing parameters. Sustainable Cities and Society, 22: 86–93.

    Article  Google Scholar 

  • Medina MA (2000). On the performance of radiant barriers in combination with different attic insulation levels. Energy and Buildings, 33: 31–40.

    Article  Google Scholar 

  • Medina MA (2012). A comprehensive review of radiant barrier research including laboratory and field experiments. ASHRAE Transactions, 118 (1): 400–407.

    Google Scholar 

  • Medina MA, Young B (2006). A perspective on the effect of climate and local environmental variables on the performance of attic radiant barriers in the United States. Building and Environment, 41: 1767–1778.

    Article  Google Scholar 

  • Mentor Graphics Cooperation (2017). FloEFD Technical Reference Version 17. Avaiable at https://www.mentor.com.

  • Miranville F, Fakra AH, Guichard S, Boyer H, Praene JP, Bigot D (2012). Evaluation of the thermal resistance of a roof-mounted multi-reflective radiant barrier for tropical and humid conditions: Experimental study from field measurements. Energy and Buildings, 48: 79–90.

    Article  Google Scholar 

  • Nahar NM, Sharma P, Purohit MM (2003). Performance of different passive techniques for cooling of buildings in arid regions. Building and Environment, 38: 109–116.

    Article  Google Scholar 

  • RIMA (2002). Reflective Insulation, Radiant Barriers And Radiation Control Coatings, 2nd Edition.

  • Roels S, Deurinck M (2011). The effect of a reflective underlay on the global thermal behaviour of pitched roofs. Building and Environment, 46: 134–143.

    Article  Google Scholar 

  • Saber HH (2013). Thermal performance of wall assemblies with low emissivity. Journal of Building Physics, 36: 308–329.

    Article  Google Scholar 

  • dos Santos GH, Mendes N (2015). Numerical analysis of hygrothermal performance of reflective insulated roof coatings. Applied Thermal Engineering, 81: 66–73.

    Article  Google Scholar 

  • Sarawak Energy (2017). Solar Energy by Sarawak Energy. Sarawak Energy. Available at https://www.sarawakenergy.com/what-we-do/power-generation.

  • Soubdhan T, Feuillard T, Bade F (2005). Experimental evaluation of insulation material in roofing system under tropical climate. Solar Energy, 79: 311–320.

    Article  Google Scholar 

  • Teh KS, Yarbrough DW, Lim CH, Salleh E (2017). Field evaluation of reflective insulation in South East Asia. Open Engineering, 7 (1): 352–362. https://doi.org/10.1515/eng-2017-0039.

    Article  Google Scholar 

  • Tong S, Li H (2014). An efficient model development and experimental study for the heat transfer in naturally ventilated inclined roofs. Building and Environment, 81: 296–308.

    Article  Google Scholar 

  • Troppová E, Tippner J, Švehlík M (2018). Numerical and experimental study of conjugate heat transfer in a horizontal air cavity. Building Simulation, 11: 339–346.

    Article  Google Scholar 

  • Wang S, Shen Z, Gu L (2012). The impact of roof pitch and ceiling insulation on cooling load of naturally-ventilated attics. Energies, 5: 2178–2196.

    Article  Google Scholar 

  • Yarbrough DW (2010). Reflective materials and radiant barriers for insulation in buildings. In: Hall MR, Materials for Energy Efficiency and Thermal Comfort in Buildings. Cambridge, UK: Woodhead Publishing. pp. 305–318.

    Chapter  Google Scholar 

  • Yarbrough DW, Teh KS, Lim CH, Salleh E, Mat S, Sulaiman MY (2016). Hybrid and reflective insulation assemblies for buildings. Journal of Power and Energy Engineering, 4: 23–31.

    Article  Google Scholar 

Download references

Acknowledgements

The authors would like to thank the National University of Malaysia (UKM) for their financial support under the grant AP-2017-006/1 and AP-2017-006/4.

Author information

Authors and Affiliations

  1. Solar Energy Research Institute (SERI), National University of Malaysia, 43600, Bangi, Selangor, Malaysia

    Muhamad Zahin Mohd Ashhar & Chin Haw Lim

Authors
  1. Muhamad Zahin Mohd Ashhar
    View author publications

    You can also search for this author in PubMed Google Scholar

  2. Chin Haw Lim
    View author publications

    You can also search for this author in PubMed Google Scholar

Corresponding author

Correspondence to Chin Haw Lim.

Rights and permissions

Reprints and permissions

About this article

Check for updates. Verify currency and authenticity via CrossMark

Cite this article

Ashhar, M.Z.M., Lim, C.H. Numerical simulation of heat transfer in a roof assembly with reflective insulation and radiant barrier. Build. Simul. 13, 897–911 (2020). https://doi.org/10.1007/s12273-020-0624-3

Download citation

  • Received:

  • Revised:

  • Accepted:

  • Published:

  • Issue Date:

  • DOI: https://doi.org/10.1007/s12273-020-0624-3

Keywords

Search

Navigation