Embodied Energy and Thermal Performance of Alternate Walling Materials in Affordable Housing in the Composite Climate of Delhi

Abstract

Meeting the affordable housing shortage in India in a short time has its environmental and social challenges. It not only requires huge resources but is also a big social responsibility to provide economical and comfortable housing for the marginalized section of society. Improper selection of construction materials may lead to the locking up of massive energy as embodied energy of materials and uncomfortable indoor living conditions. The present study focuses on the need for consideration of both embodied energy and thermal performance in the selection of materials for the building envelope in naturally ventilated affordable housing in India. Walling materials form a major part of the building envelope and thus it's crucial to assess their performance. This paper presents an analysis of embodied energy and thermal performance of fly ash Bricks, AAC blocks, and RCC precast panels as walling options in comparison to conventional walling material of burnt clay brick in the composite climate zone of Delhi. This analysis is being carried out for the alternate walling solutions in practice or emerging for mid to high-rise EWS housing construction in this region. The embodied energy values per cubic meter are compared for each wall assembly for the lifecycle stage cradle to gate. Thermal simulation results are presented in terms of indoor operative temperatures achieved by each wall type material and compared with the comfort temperature range prescribed by the comfort model IMAC-R, 2022 to find out the ‘discomfort degree hours’. The results of the study underscore the suitability of fly ash bricks and AAC blocks as sustainable alternatives due to their lower embodied energy compared to traditional burnt clay bricks base case. Fly ash bricks even outperform the base case in terms of thermal comfort. The study discourages the use of burnt clay bricks due to very high embodied energy. The study also strongly discourages the use of RCC panels in the composite climate as they exhibit both poor thermal comfort and high embodied energy. The study findings would help government agencies to make environmentally and socially conscious decisions about the use of walling materials on a large scale in meeting the affordable housing demand.