| Plastic Solar Water Heater

Conventional solar water heaters were plagued with many problems in remote communities. Two prototypes were tested - one which used black low density polyethylene (LDPE) reticulation tubing in the collector and the other which used high density polyethylene (HDPE) swimming pool heating batts. Each of these materials were cheap and readily available. Several other prototypes were later developed from different plastics. One was a low pressure, semi-glazed, thermosyphon system.

The absorber of this prototype was made from an extruded ethylene-propylene-diene-monomer (EPDM) section (manufactured for swimming pool heating), mechanically jointed to cPVC header manifolds with acetal nozzles and neoprene grommets. Glazing was in
the form of clip-on acrylic panels (again not liable to be smashed), and collector insulation in polystyrene foam. The storage tank was an innovation resulting from contemplation of the popular wine cask.

In each of these systems a plastic bladder was supported on all sides by rigid sheetmetal walls of 4-litre and 1000-litre volumes respectively. The solar water heater tank was designed with a roughly 200-litre volume. All of the materials used in the construction of this system were relatively inexpensive and readily available. The system was supplied in kit form to be constructed on site by community members. The aim being to enable communities to maintain the system, and repair it if it broke down. The solar water heaters were installed for field trials on RAHFs at Newman, Pundulmurra College, Kalgoorlie and Halls Creek.