Comparative life-cycle assessment of constant air volume, variable air volume and active climate beam systems for a Swedish office building

Energy use in buildings has a significant influence on the global energy demand and environmental impacts. Among all building systems, heating, ventilation, and air conditioning (HVAC) systems are the most energy-intensive in terms of their total energy requirements. The production and operation of HVAC systems have a significant impact on the environment. These systems are also among the largest consumers of natural resources and materials in the building sector. With an ever-increasing focus on energy and material use, the question remains, which HVAC system has a better environmental performance. This paper presents a comparison between the life cycle impacts of three different HVAC systems — Constant Air Volume (CAV), Variable Air Volume (VAV) and Active Climate Beams (ACB) — designed for a Swedish modern office building. The system boundary of the life cycle assessment is cradle-to-grave with options, over a 20-year period. The life cycle assessment (LCA) of the three systems has been performed using SimaPro software. The CML IA (baseline) method has been used for the impact assessment. The life cycle impacts have been weighted using the Dutch shadow cost method. The results show that from a life cycle perspective, the ACB and VAV systems have comparable environmental performance. The CAV system is shown to have the worst overall environmental performance. The manufacturing phase of the ACB system exhibits the highest environmental impacts among the three systems, reflecting its high use of copper. The operational phase is the main contributor to the environmental burden for all three systems.