Design Optimisation Strategies for Solid Rammed Earth Walls in Mediterranean Climates

The renewed attention paid to raw earth construction in recent decades is linked to its undoubted sustainability, cost-effectiveness, and low embodied energy. In Italy, the use of raw earth as a construction material is limited by the lack of a technical reference standard and is penalised by the current energy legislation for its massive behaviour. Research experiences, especially transoceanic, on highly performative contemporary buildings made with natural materials show that raw earth can be used, together with different types of reinforcements, to create safe, earthquake-resistant, and thermally efficient buildings. On the basis of experimental data of an innovative fibre-reinforced rammed earth material, energy analyses are developed on a rammed earth building designed for a Mediterranean climate. The paper focuses on the influences that different design solutions, inspired by traditional bioclimatic strategies, and various optimised wall constructions have in the improvement of the energy performance of the abovementioned building. These considerations are furthermore compared with different design criteria aiming at minimising embodied carbon in base material choice, costs, and discomfort hours. Results have shown the effectiveness of using the combination of massive rammed earth walls, night cross ventilation, and overhangs for the reduction of energy demand for space cooling and the improvement of wellbeing. Finally, the parametric analysis of thermal insulation has highlighted the economic, environmental, and thermophysical optimal solutions for the rammed earth envelope.

[1]  Robert Fuller,et al.  Energy use and thermal comfort in a rammed earth office building , 2008 .

[2]  Greg Knowles,et al.  A passive wall design to minimize building temperature swings , 1984 .

[3]  J. Aubert,et al.  Hygrothermal properties of earth bricks , 2014 .

[4]  M Mahmudul Hasan,et al.  Investigation of energy performance of a rammed earth built commercial office building in three different climate zones of Australia , 2015 .

[5]  Koray Ulgen,et al.  Experimental and theoretical investigation of effects of wall’s thermophysical properties on time lag and decrement factor , 2002 .

[6]  David Allinson,et al.  Hygrothermal analysis of a stabilised rammed earth test building in the UK , 2010 .

[7]  Sukumar Natarajan,et al.  Thermal inertia of heavyweight traditional buildings: experimental measurements and simulated scenarios , 2017 .

[8]  O. Douzane,et al.  Incorporation of thermal inertia in the aim of installing a natural nighttime ventilation system in buildings , 1999 .

[9]  Xiang Dong,et al.  Strategies for reducing heating and cooling loads of uninsulated rammed earth wall houses , 2014 .

[10]  Ka Heathcote,et al.  The thermal performance of earth buildings , 2011 .

[11]  Jean-Claude Morel,et al.  On the relevance of neglecting the mass vapor variation for modelling the hygrothermal behavior of rammed earth , 2015 .

[12]  Lídia Rincón,et al.  Improving thermal comfort of earthen dwellings in sub-Saharan Africa with passive design , 2019, Journal of Building Engineering.

[13]  Francesco Patania,et al.  The Retrofit of Existing Buildings Through the Exploitation of the Green Roofs – A Simulation Study , 2014 .

[14]  Giuseppe Peter Vanoli,et al.  Energy retrofit of historical buildings: theoretical and experimental investigations for the modelli , 2011 .

[15]  M. R. Hall,et al.  Analysis of the hygrothermal functional properties of stabilised rammed earth materials , 2009 .

[16]  Hugo Houben,et al.  Traité de construction en terre , 1989 .

[17]  Chris Beckett,et al.  Life cycle analysis of environmental impact vs. durability of stabilised rammed earth , 2017 .

[18]  F. Nocera,et al.  Daylight Performance of Classrooms in a Mediterranean School Heritage Building , 2018, Sustainability.

[19]  Cristina Cornaro,et al.  Dynamic simulation and on-site measurements for energy retrofit of complex historic buildings: Villa Mondragone case study , 2016 .

[20]  Laetitia Fontaine,et al.  Hygro-thermo-mechanical properties of earthen materials for construction : a literature review , 2012 .

[21]  F. Nocera,et al.  Hygrothermal Properties of Raw Earth Materials: A Literature Review , 2019, Sustainability.

[22]  Daniel Hoornweg,et al.  What a waste? : a global review of solid waste management , 2012 .

[23]  M Krayenhoff.  Rammed earth thermodynamics , 2015 .

[24]  Niccolò Aste,et al.  The influence of the external walls thermal inertia on the energy performance of well insulated buildings , 2009 .

[25]  Armando C. Oliveira,et al.  A field study on building inertia and its effects on indoor thermal environment , 2012 .

[26]  Luisa F. Cabeza,et al.  Adaptation of rammed earth to modern construction systems: Comparative study of thermal behavior under summer conditions , 2016 .

[27]  B. V. Venkatarama Reddy,et al.  Embodied energy in cement stabilised rammed earth walls , 2010 .

[28]  A. Mukherjee,et al.  Rammed earth blocks with improved multifunctional performance , 2018, Cement and Concrete Composites.

[30]  Pierre Michel,et al.  Experimental assessment of thermal inertia in insulated and non-insulated old limestone buildings , 2014 .

[31]  H. Asan,et al.  Effects of Wall's thermophysical properties on time lag and decrement factor , 1998 .

[33]  Xing Jin,et al.  Thermal performance evaluation of the wall using heat flux time lag and decrement factor , 2012 .

[34]  P. Hickson.  Earth Building—how does it rate? , 2015 .

[35]  Francesco Patania,et al.  Assessment of the dynamic thermal performance of massive buildings , 2014 .

[36]  Maria-Mar Fernandez-Antolin,et al.  Passive Design Strategies for Residential Buildings in Different Spanish Climate Zones , 2019, Sustainability.

[37]  Meral Özel,et al.  Optimum location and distribution of insulation layers on building walls with various orientations , 2007 .

[38]  Azra Korjenic,et al.  Thermal conductivity of unfired earth bricks reinforced by agricultural wastes with cement and gypsum , 2015 .

[39]  Jean-Claude Morel,et al.  Earthen materials and constructions , 2020, Nonconventional and Vernacular Construction Materials.

[40]  G Giuffrida,et al.  An overview on contemporary rammed earth buildings: technological advances in production, construction and material characterization , 2019 .

[41]  Maria Rosa Trovato,et al.  Technological, Axiological and Praxeological Coordination in the Energy-Environmental Equalization of the Strategic Old Town Renovation Programs , 2020 .

[42]  Rachel Cardell-Oliver,et al.  Measured and simulated thermal behaviour in rammed earth houses in a hot-arid climate: Part B: Comfort , 2017 .

[43]  R. Griffiths,et al.  Sustainable earth walls to meet the building regulations , 2005 .

[44]  F. Nocera,et al.  Energetic Retrofit Strategies for Traditional Sicilian Wine Cellars: A Case Study , 2020, Energies.

[45]  B. P. Jelle,et al.  Hygrothermal properties of compressed earthen bricks , 2018 .

[46]  J. Morel,et al.  Energy evaluation of rammed earth walls using long term in-situ measurements , 2017 .

[47]  Gianpiero Evola,et al.  Synergic effects of thermal mass and natural ventilation on the thermal behaviour of traditional massive buildings , 2016 .

[48]  Luisa F. Cabeza,et al.  Experimental rammed earth prototypes in Mediterranean climate , 2014 .

[50]  Francesc Xavier Massó Ros,et al.  Thermal improvement of rammed earth buildings by the inclusion of natural cork , 2014 .