Air Conditioning Energy Saving by Rooftop Greenery System in Subtropical Climate in Australia

The benefits of rooftop greenery systems (such as
energy savings, reduction of greenhouse gas emission for mitigating
climate change and maintaining sustainable development, indoor
temperature control etc.) in buildings are well recognized, however
there remains very little research conducted for quantifying the
benefits in subtropical climates such as in Australia. This study
mainly focuses on measuring/determining temperature profile and air
conditioning energy savings by implementing rooftop greenery
systems in subtropical Central Queensland in Australia. An
experimental set-up was installed at Rockhampton campus of Central
Queensland University, where two standard shipping containers (6m
x 2.4m x 2.4m) were converted into small offices, one with green
roof and one without. These were used for temperature, humidity and
energy consumption data collection. The study found that an energy
savings of up to 11.70% and temperature difference of up to 4°C can
be achieved in March in subtropical Central Queensland climate in
Australia. It is expected that more energy can be saved in peak
summer days (December/February) as temperature difference
between green roof and non-green roof is higher in December-
February.

• M. Anwar
• M. G. Rasul
• M. M. K. Khan

• Extensive green roof
• Rooftop greenery system
• Subtropical climate
• Shipping container.

<p>[1] Buildings (2013) retrieved from http://www.climatechange.gov.au/en/
what-you-need-to-know/buildings.aspx accessed on April 20, 201.
[2] Energy in Australia 2012, Department of Resources Energy and
Tourism, available from http://www.abares.gov.au.
[3] T. Markis, J.A. Paravantis, Energy Conservation in small enterprises,
Energy and Buildings 39, 2007, pp. 404-415.
[4] M.M. Rahman, M.G. Rasul and M.M.K. Khan (2008), Energy
Conservation Measures in an Institutional Building by Dynamic
Simulation Using DesignBuilder, Proceedings of the 3rd
IASME/WSEAS International Conference on Energy &amp; Environment
(EE&lsquo;08), Paper Number: 565-266, pp. 192-197, University of
Cambridge, Cambridge, UK, February 23-25.
[5] J.A. Clarke, Assessing Building Performance by Simulation, Building
and Environment 28, 1993, pp. 419-427.
[6] T. Emilsson, Vegetation development on extensive vegetated green
roofs: Influence of substrate composition, establishment method and
species mix. Ecol. Eng. 33, 2008, pp. 265-277.
[7] J. Mentens, D.Raes, M.Hermy, Green roofs as a tool for solving the
rainwater runoff problem in the urbanized 21st century? Landscape and
Urban Planning 77 (3), 2006, pp. 217-226.
[8] E. Ekaterini, A.Dimitris, The contribution of a planted roof to the
thermal protection of buildings in Greece, Energy and Buildings 27(3),
1998, pp. 29-36.
[9] E.P. Del Barrio, Analysis of the green roofs cooling potential in
buildings, Energy and Buildings 27, 1998, pp. 179&ndash;19.
[10] ZinCo GMBH, Green Roofs: Recommended Standards for Designing
and Installation on Roofs, 6th edition, Zinco GmbH, Germany, 2000.
[11] Bureau of Meteorology, (BOM), Australia, Climate data online retrieved
from http://www.bom.gov.au/climate/data.
[12] Climate data online retrieved from http://www.rockhampton.
climatemps.com/
[13] M. Anwar, M.G. Rasul and M.M.K. Khan (2013), Thermal Performance
Analysis of Rooftop Greenery System in subtropical climate of
Australia, 7th WSEAS International Conference on Renewable Energy
Sources 2013, April 2-4, 2013, Kuala Lumpur, Malaysia.
[14] N.S.G. Williams, J.P.Rayner, Green roofs for a wide brown land:
Opportunities and barriers for rooftop greening in Australia. Urban
Forestry &amp; Urban Greening 9, 2010, pp. 245-251.
[15] Elmich, Sustainable eco-friendly landscapes and architectural products,
2013, available from http://www.elmich.com.
[16] N.H. Wong, Y. Chen, C.L.Ong, A.Sia, Investigation of thermal benefits
of rooftop garden in the tropical environment. Build. Environ. 38, 2003,
pp. 261&ndash;270.
[17] DesignBuilderDocumentation. (2012), DesignBuilderUser Manual,
Version 3.0. UK:DesignBuilder Software Limited.</p>