Abstract

Previous studies have reported that the adoption of thermosyphon fluid circulation can reduce the capital cost of solar water heating systems. Well designed thermosyphon systems are as effective as pumped systems but with lower capital and running costs. To investigate this; two experiments were undertaken. Firstly a thermosyphon heat-pipe Evacuated Tube Solar Water Heater (ETSWH) was assembled using a proprietary collector and its performance monitored under a northern maritime climate. Secondly a transparent physical model was fabricated to the same dimensions as the proprietary collector’s manifold and the internal fluid flow regime was observed using particle imaging velocimetry. The annual monitored performance of the thermosyphon heat-pipe ETSWH demonstrated that this system could supply a solar fraction of 0.4, 0.45 and 0.71 towards the average hot water load of a detached, semi detached and terraced dwelling respectively.