Mobile QR Code QR CODE : Korean Journal of Air-Conditioning and Refrigeration Engineering
Korean Journal of Air-Conditioning and Refrigeration Engineering

Korean Journal of Air-Conditioning and Refrigeration Engineering

ISO Journal TitleKorean J. Air-Cond. Refrig. Eng.
  • Open Access, Monthly
Open Access Monthly
  • ISSN : 1229-6422 (Print)
  • ISSN : 2465-7611 (Online)
Title Hydrogen-LNG Co-firing Test Study in a 20 kW Domestic Boiler
Authors Sae Byul Kang ; Jae Joon Choi ; Hyun Hee Lee
DOI https://doi.org/10.6110/KJACR.2025.37.2.63
Page pp.63-71
ISSN 1229-6422
Keywords 혼소; 연소; 가정용 보일러; 효율; 수소 Co-firing; Combustion; Domestic boiler; Efficiency; H2
Abstract Carbon emissions are inevitable from fossil fuel-based technologies such as LNG and heavy oil. In this context, we present hydrogen combustion technology as a fundamental thermal solution for achieving carbon neutrality. The feasibility of hydrogen combustion was confirmed through a simple nozzle hole combustion test. Following this initial test, a 20 kW domestic boiler was modified to evaluate H2-LNG combustion, conduct pure LNG combustion experiments, and carry out H2-LNG co-firing and pure hydrogen combustion tests. During the pure LNG combustion test, boiler thermal efficiencies and NOx emissions were compared across various boiler thermal loads and combustion air ratios. The results indicated that a lower O2 concentration in the exhaust gas corresponded to relatively higher boiler efficiency. The H2-LNG co-firing tests were conducted at co-firing rates ranging from 21% to 71%. The thermal efficiency during co-firing was found to be reduced by approximately 1-2% compared to the pure LNG combustion test. In the pure hydrogen combustion experiments, NOx emissions were found to be about 4 to 5 times higher than those of LNG combustion.