* Corresponding author: hasna.louahlia@unicaen.fr Comparison of the thermal performance between conventional and cob building Kaoutar Zeghari 1 , Hasna Louahlia 1,* , Malo Leguern 2 , Mohamed Boutouil 2 , Hamid Gualous 1 , Michael Marion 1 , Pierre Schaetzel 1 , Steeve Goodhew 3 and François Streif 4 1 Normandy University, LUSAC-Unicaen, Site universitaire Bellevue, 50000 Saint Lô, France 2 ESITC Caen, Campus 2, 14610 Epron, France 3 Plymouth University, Drake Circus, Plymouth PL4 8AA, UK 4 Cotentin and Bessin marshlands regional national park, France Abstract. The appliance of sustainable development approach in building has urged construction industry to adopt proper measurements to protect environment and reduce residential building energy consumption and CO2 emissions. Thus, an increasing interest in alternative building materials has developed including the use of bio-based materials such as cob which is studied in this paper. In the previous work, many experimental and numerical studies have been carried out to characterize thermal behaviour of earth buildings, reduce its thermal conductivity and water content. In this paper, an experimental study is carried out to determine the thermal properties and energy performance of cob building. Cob samples within different soil and fiber contents are studied using an experimental set up instrumented with flux meters and micro- thermocouples in order to evaluate the local heat flux and thermal conductivity during stationary regime. The results are analysed and compared to deduce the performant mixes in terms of thermal behaviour while respecting the French thermal regulation. A static thermal simulation based on RT 2012 calculation method (the official French calculation method for the energy performance of new residential and commercial buildings according to France thermal regulation) is used to compare energy performance between conventional and cob building using the French climate data base . 1 Introduction Since the last past years, contemporaneous concerns about energy consumption and greenhouse gas emissions have rapidly immerged intriguing environmentalists, researchers and public consciousness. There has been an important influence of energy consumption on the economic progress leading to raise awareness about effective resources monitoring [1]. According to the last report “International Energy Outlook 2013”of the Energy Information Administration (EIA, 2013) the world energy consumption will rise to 56% between 2010 and 2040.Yet, Built environment is a substantial consumer of energy, according to Saidur R et al. [2] the residential energy consumption reached 31% of the world energy in 2009. In the USA, primary energy consumption in the residential sector is estimated around 54% of consumption in the building sector, while in the EU it has increased by around 1%/year since 1990 (Environment and Energy Management Agency, 2012). As a response to the increasing energy consumption in buildings, many policies and means have been adopted in order to promote energy efficiency and sustainable buildings [3]. Therefore, an increasing interest in alternative building materials such as bio-based materials particularly earth has arisen because of the extensive environmental problems such as climate change and the impoverishment of resources combined with the rapid technological advancement within the building sector. Earth is often acknowledged as sustainable building material, based on its low embodied energy [4]. As described by Hamed et al [5], there are different types of earth buildings such as: Rammed earth buildings, Adobe, Wattle and Daub, Poured earth and cob that is studied in this paper. Thus, Cob which is defined as a mixture of earth and fibers that is then mixed with water has been used long- time ago thanks to its suitable construction properties. It has the advantage of fulfilling all strength and service ability requirements for thermal building performance. Earth construction materials are not renewable materials but can be reused while keeping their thermal properties within low thermal resistance. Many authors [6] have shown that the thermal conductivity in earth building can vary from 0.47 to 1 W/m°C according to straw content, density and water content. Many experimental and numerical studies have been carried out to characterize thermal behavior of earth buildings. Mansour et al. [7] demonstrated the use of optimal bulk density of 1750 kg.m -3 makes possible to reach the objective of reducing thermal conductivity of the CEB (compressed earth blocks) to 0.75W m -1 K -1 . Meukam et al. [8] have carried out an experimental study on the thermal properties of bricks made from lateritic soil. The obtained results present a rapid increase for low water content and a maximum diffusivity for a water content of 14% for laterite and 8% for laterite with addition of natural pozzolan or sawdust. Lucile Soudani, Monika Woloszyn et al [9] investigated thermal performance about a real case study. The house studied is located in Saint-Antoine l’Abbaye, in Isère, South-Eastern France. The house affords a good comfort in summer within regards to stability and level of temperatures. Besides, it provides a good energy performance in winter because temperature gets comfortable with a very low heating load. Results ,0 (201 Web of Conferences https://doi.org/10.1051/e3sconf/2019111030 9) 201 E3S 111 CLIMA 9 300 03 3 © The Authors, published by EDP Sciences. This is an open access article distributed under the terms of the Creative Commons Attribution License 4.0 (http://creativecommons.org/licenses/by/4.0/).