Evaluating whole life carbon impact of climate control systems in net-zero building designs

Abstract

This paper proposes a methodology for the early-stage selection of climate control systems in building design, focusing primarily on minimising whole life carbon (WLC) emissions. A significant obstacle is the limited availability of comprehensive data on the carbon footprint of Heating, Ventilating and Air Conditioning (HVAC) equipment and materials, along with the challenges or absence of early-stage energy models and detailed HVAC designs. This paper presents and compares the WLC for seven different HVAC systems and designs for an office building. The study demonstrates how HVAC engineers and designers can make informed decisions by selecting HVAC systems, materials, and components in the early stages. It illustrates the outcomes of a typical project design from both WLC and operational energy perspectives. Additionally, the paper provides normalised WLC benchmarks for each system in terms of kgCO₂e per square metre of floor area.

Practical Applications: This study provides practical guidance for HVAC engineers and designers in achieving net-zero building goals by minimising Whole Life Carbon (WLC) across seven climate control systems. The developed benchmarking tool enables early-stage selection of these systems by normalising embodied and operational carbon data per square metre of floor area, facilitating direct comparisons. Insights into the benefits of low-GWP refrigerants and efficient designs support the adoption of sustainable solutions. The integration of operational energy and consideration of decarbonising grids ensure future-proof designs that remain effective under evolving energy conditions. The study offers valuable benchmarks and actionable strategies to support industry decision-making and policy development for reducing the environmental impacts of HVAC systems.