Modelling temperature in premise plumbing systems

ABSTRACT In this work, our main objective is to introduce, calibrate and validate a temperature model that simulates temperature fluctuations due to radial and axial heat transfer in cold- and hot-water pipes within premise plumbing systems. For this purpose, a laboratory pilot containing six shower installations was used to evaluate three setups of varying pipe material, temperature and insulation. The axial convection factor was calibrated with an initial test on the cold-water system. The results show that the calibrated model was able to accurately represent temperature fluctuations in most showers for all tests in the pilot, obtaining relatively low error. These findings also imply that water temperature fluctuations caused by non-radial heat transfer in premise plumbing systems are detectable and non-negligible during periods of low or no demand. Therefore, it is recommended to monitor and model these fluctuations, when possible, especially in the vicinity of mixing valves and hot-water heaters.