| Abstract | Drain water heat recovery heat exchangers are employed to capture thermal energy from water flowing down drain stacks in residential buildings. This technology is crucial for designers aiming to enhance energy efficiency in Canadian homes, with NBC Tier 5 energy performance being significantly challenging without it. However, understanding and addressing the nuances in the performance of this technology is essential. This report investigates how different plumbing configurations affect the same heat exchanger while maintaining a consistent flowrate and temperature at the showerhead. Essentially, it measures the in-situ impact of plumbing configurations on the heat exchangers' performance, providing valuable insights for designers and codes committees to make informed decisions regarding this technology. Findings reveal that plumbing configurations greatly affect heat exchanger performance, with each configuration offering distinct advantages. The results showed that the energy savings associated with the same shower event could differ by more than 30% for the most and least effective configurations tested in this work. Notably, the greatest savings come with the highest penalty (i.e., pressure drop), and the most efficient setup might not always be the best fit for a specific dwelling. This decision is highly dependent on the plumbers' preferences and priorities. The report discusses metrics such as 1) energy saving, 2) pressure drop, and 3) legionella potential, advising codes committees to consider all these factors, which are influenced by the home's plumbing configuration, regardless of the installed heat exchanger. |
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