On the influence of concrete-straw-plaster envelope thermal mass on the cooling and heating loads for different climatic zones of India

Abstract

Incorporating insulation material in the building envelope is one of the simple yet effective passive techniques aimed at mitigating the energy consumption in buildings. The development and utilization of sustainable materials with heat insulating capacity as an alternative to synthetic insulations is a promising path towards reduced carbon footprint of buildings. The insulation potential of straw, an agricultural waste, in the context of the wide-ranging climate of India is the focus of the current work. Cooling and/or heating load analysis over 24 h of a representative summer and winter day is performed through transient numerical analysis for five climatic zones of India. Three building envelope configurations possible with retrofitting straw insulation (placed on the outside or inside or equally on either side) over existing walls/roof are compared. Four different thicknesses (10, 20, 30 and 40 cm) of the straw insulation are considered for analysis. Recommendations of envelope configuration with insulation are proposed based on energy and cost savings for the different climatic zones. Overall, the case of straw insulation split on either side performs the best. Energy savings in the range of 67–96% is achievable with the addition of just 10 cm thick straw across different climatic zones. The work also presents a comparison of the straw envelope performance against different types of envelopes based on sustainable materials found in literature.