Multi-case study on the carbon emissions of the ecological dwellings in cold regions of China over the whole life cycle

Zhixing Luo,Yiqing Lu

doi:10.1177/0144598720934054

Abstract

This study employed the bottom-up life cycle assessment method, examining the life cycle carbon emissions of three dwellings constructed at different times with different techniques in Yinchuan City, China, i.e. traditional earth brick dwelling (Case 1), brick–straw bale dwelling (Case 2), wood–straw solar energy dwelling (Case 3). The study aimed to find the methods of reducing carbon emissions, so as to slow down the global warming. The results showed that (1) with excellent thermal insulation properties, straw bale was remarkably effective in reducing carbon emissions from heating at the use stage; (2) 15 kWp solar photovoltaic panels contributed to offsetting the carbon emission of the dwelling; (3) straw bales and logs could store the carbon in building envelope, which partly offset the carbon emissions. The findings of this study have proved that ecological building materials and solar photovoltaic system have great potential in reducing carbon emissions of buildings, and can provide a basis for the design and material selection of future dwellings in order to promote the development of green dwellings.

Highlights

There is an increasing evidence showing that the overconsumption of fossil fuel has led to global warming and the most influential factor is the emission of greenhouse gases (Luo et al, 2016)
economic input–output LCA (EIO-LCA) is a top-down method which calculates the energy consumption and carbon emission based on the amount of money spent on; it is able to obtain the data about the carbon emission of all upstream supply chains through calculating the total monetary amount of construction industry spent on energy consumption
The carbon emission during building operation can be reduced by over 60% when the wall is built with straw bales compared with walls without them

Summary

Introduction

There is an increasing evidence showing that the overconsumption of fossil fuel has led to global warming and the most influential factor is the emission of greenhouse gases (Luo et al, 2016). Construction is one of three major sources of greenhouse gases (Lu and Yang, 2013) and the carbon emissions over a life cycle have aroused wide concern among increasingly more researchers worldwide (WBCSD, 2008). Vernacular dwelling, as the earliest building type that is most closely related to humans and exists in the largest number, is the most sustainable building type (Lu and Yang, 2013). Different from urban buildings, most vernacular dwellings are constructed by residents spontaneously and mainly scattered individually, thereby lacking the use of modern technologies and overall planning and building standards. The growth in total size of dwellings spurs the growth of energy consumption and carbon emissions in two aspects: (1) the manufacturing of considerable non-renewable building materials consumes plenty of energy and (2) the ever-increasing building area results in the large amount of operating energy consumption

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