Deadleg losses from a simulated domestic hot water system
Thesis DisciplineMechanical Engineering
Degree GrantorUniversity of Canterbury
Degree NameMaster of Engineering
This report considers the factors determining the deadleg losses of horizontal 'supply' hot water copper pipes, in a dynamic simulation rig of a domestic hot water system in the laboratory of the Mechanical Engineering Department at the University of Canterbury. In order to simulate the calculated system daily deadleg losses for a real house for which the ambient te1nperature was low* and the room temperature was l8°C, an air-conditioning unit was used to supply cool air blowing through the five sections of 75 mm ID PVC air 'tunnels' which were built over the horizontal 'supply' hot water copper pipes [photo 1]. Thus the effect of deadleg losses due to natural-convection heat transfer in an ordinary domestic house was simulated experimentally by using forced-convection heat transfer in the rig. Quantitative values of deadleg losses at different usage patterns and tank temperatures are tabulated. *5.7°C as ambient temperature was being used in this project. It was the most severe daily average temperature of Christchurch in July (1960-1969) - data from Meteorological Office at the airport of Christchurch, New Zealand.