Comparative carbon emission assessment of vertical and modular ground source heat pump systems

Abstract

The urgent need to address climate change necessitates a reduction in carbon emissions, particularly within the building sector. To achieve carbon neutrality, innovative technologies such as carbon capture, renewable energy systems, and carbon-neutral materials have been developed. However, there remains a dearth of research quantitatively analyzing carbon emissions through a life cycle assessment while implementing these technologies in real-world building scenarios. Additionally, Ground-source Heat Pumps (GSHPs) demonstrate superior efficiency compared to Air-source Heat Pumps (ASHPs) by leveraging stable ground temperatures, yet their widespread adoption is hindered by high initial investment costs. This study compares and analyzes the carbon emissions of GSHPs with Modular Ground Heat Exchangers (MGHXs), designed to mitigate initial investment barriers, alongside Vertical Ground Heat Exchangers (VGHXs) and ASHPs. The primary objective is to evaluate technology adoption feasibility from a carbon equivalent perspective, focusing on energy demand through building energy simulation. Results indicate that MGHXs exhibit a 6.7 % reduction in carbon emissions compared to VGHXs during production and construction (stage A). However, MGHXs generate 0.57 CO2-eq more per square meter per year during building operation (stage C). The implementation of geothermal energy systems in new buildings across South Korea could potentially achieve a maximum reduction effect of 11.6 % concerning the country's NDC (Nationally Determined Contributions) 2030 carbon reduction target.