Earth Notes: General Bibliography (raftery2024hydronic)

• [raftery2024hydronic] Raftery, Paul and Singla, Rupam and Cheng, Hwakong and Paliaga, Gwelen Insights from hydronic heating systems in 259 commercial buildings (accessed 2024-09-15), Elsevier BV, 2024-10-15, Energy and Buildings, volume 321, ISSN 0378-7788, doi:10.1016/j.enbuild.2024.114543, article/pages 114543 (article) (BibTeX).
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  [Highlights: "Systems typically operate 81% of hours annually, far more frequently than expected. Loads are very low relative to equipment capacity, causing inefficient operation. Typical condensing boilers spend few hours at low return temp., reducing efficiency." Quote: "... hydronic heating system, often called a heating hot water system (HHW) in the US..." Quote: "This paper's primary goals are to: 1) share a large dataset of building automation system data for heating hot water systems in commercial buildings, 2) analyze it to better understand how these systems operate in practice, and 3) identify opportunities for reducing the emissions these systems generate." Quote: "Almost all buildings (146 of 152) have right-skewed HW load distributions when operating. Fig. 6 (a) shows the load distribution for three example buildings, selected based on low, median and high skewness. Though skewness is expected for these distributions, the degree is typically quite high (median: 1.1), meaning that the majority of these systems spend most of the time operating at low loads, with rare periods at high loads. Thus, ensuring a system can operate efficiently at low load is a key aspect of performance. However, few systems are designed to operate efficiently below 10% of design capacity despite the fact that loads are frequently below this." Quote: "... multiple pieces of smaller, accurately sized and appropriately staged heating equipment with good turn-down capability (e.g. 10:1 or more) are key components of a heating system design that can efficiently serve the loads it encounters. Without due care and attention, the combined issues of oversizing and poor turn-down can yield very low operating efficiency (e.g. < 40%)."]