• Energy Research

Abstract Buildings contribute a significant portion of global greenhouse gas emissions and have the potential for large-scale impact reductions. Reducing the whole-life impacts of buildings is critical for creating a net-zero carbon built environment. For this to be achieved, the whole-life carbon impacts of design decisions must be considered during the building design process. A systematic review of academic literature was conducted to assess how life cycle assessment (LCA) is incorporated at various stages of the building design process, and what improvements are needed to support net-zero carbon design. The review compiled 274 papers that were published up to the end of 2019, of which 108 were subject to detailed review following screening. The review found that LCA is generally used late in the design process, when it is too late to greatly influence the design. Incorporating LCA with either building information modelling or life cycle costing is seen to have the same challenges as undertaking a traditional LCA. Parametric methods show promise for design development, but tools and algorithms require further verification and regionalisation to be implemented throughout industry. The use of benchmarks, target values and other pre-populated information can be used to incorporate life-cycle thinking without the need to undertake a detailed LCA. The review has demonstrated that LCA continues to face barriers, in both methods and practice, preventing its ability to guide early-stage design decisions and have a large impact on the environmental performance of buildings.

Several regulations and standards have been developed to reduce the carbon footprint of buildings, but these have failed to provide a clear pathway to a net zero future. Hence, we recently introduced the Active Building Code (ABCode). This provides guidance on reducing the environmental impact of the next generation of buildings, termed Active Buildings (ABs), through their synergy with the grid. This paper aims to illuminate the regulatory landscape, justify our initial proposal for the ABCode, and reveal opportunities and challenges to the popularisation of ABs. Twelve online focus group discussions were conducted, with thirty stakeholders in total, all selected on the basis of their expertise. A grounded theory approach identified five core themes in such discussions. These strongly overlap with what is incorporated in the ABCode, suggesting the code successfully captures issues important to experts. Stakeholders defined ABs as responsive buildings and proposed both energy and carbon are considered in their assessment. They hence aligned with the definition and evaluation framework proposed by the ABCode. Finally, stakeholders considered people’s tendency to prioritise capital cost as the greatest challenge to the popularisation of ABs, and the increasing demand for healthy environments as its greatest opportunity.

Abstract An ‘integrated appraisal’ of a solar hot water (SHW) system in the UK residential sector was carried out to assess its overall energetic, environmental and economic performance. The energy analysis indicates that when displacing a gas boiler, oil boiler, or electrical immersion heater, the SHW system would provide a net energy benefit for the majority of its estimated 25 year lifetime, thus enhancing energy security by reducing the use of, and dependence upon, conventional energy resources (mainly fossil fuels). A life cycle assessment was carried out to determine a range of environmental implications of installing and using the SHW system. It was shown that the use of aluminium has the greatest impact within the production of the system. During its use, the SHW provides the largest environmental externality benefits when displacing electricity. The economic assessment indicates that the SHW system is currently uncompetitive given the negative net present values of the various scenarios assessed. This outcome included the internalisation of the social costs of carbon. There are, however, future prospects for reduced capital costs that may significantly improve the economic performance of the system.