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 Experimental Evaluation of Condensing Boiler and Indoor Thermal Performance under Low-Temperature Heating in an Apartment Building
Authors Min Kyu Bang ; Chan Kyu Kim ; Hyusan Jang ; Yong Min Song ; Seung Hyo Baek ; Myoung Souk Yeo
DOI https://doi.org/10.6110/KJACR.2026.38.9.481
Page pp.481-488
ISSN 1229-6422
Keywords 보일러 효율; 콘덴싱 보일러; 에너지 성능; 실내 열쾌적; 저온수; 공급수 온도 Boiler efficiency; Condensing boiler; Energy performance; Indoor thermal comfort; Low temperature water; Supply water temperature
Abstract Recent studies have explored the use of low-temperature water supply heating in district heating systems. However, research on low-temperature water supply heating using condensing boilers in individual heating systems remains limited, despite approximately 52.4% of residential buildings in Korea relying on such systems. This study assesses the suitability of low-temperature water supply for individual heating through comparative experiments conducted in an 84 m² experimental house in Sejong City, evaluating both low- and high-temperature water supply. Performance was measured based on boiler efficiency and the ability to maintain indoor temperatures. The average boiler efficiency for the low-temperature case was 84.4%, surpassing the 78.4% efficiency observed for high-temperature supply, largely due to the condensing zone operating for 96.3% of the total time. Furthermore, the duration of thermal comfort was longer under low-temperature conditions (56.1 hours) compared to high-temperature conditions (43.4 hours). While neither scenario experienced underheating, the high-temperature conditions resulted in greater temperature overshooting, leading to deviations from the comfort range.