MACSOL - A Cheap New Solar Water Heater
Abstract
This paper describes a new design for building large, cheap solar water heaters using a combination of synthetic rubber and metal. The collection efficiency is quite good and the cost is low. A typical system was built for under EU100/m2 in Scotland in 2010. INTRODUCTION Solar water heating works but is still too expensive in capital costs. The aim is to prove cost-effectiveness and it is probably much easier to achieve that by reducing cost rather than increasing efficiency. There are many different approaches to reducing costs, including using cheaper materials, increasing the scale of production and also using new designs. This paper describes one such new design which appears to be successful. DESIGN Basically the collector is made of a number of layers. Firstly, the foundation or base-board is made of wooden board such as plywood or OSB(oriented strand board). Then a layer of insulation material is laid on top of the base- board. Then a grid of synthetic rubber pipes is laid on top of the insulation. Then a sheet of conductive metal is laid on top of the pipes and screwed to the baseboard with wood screws so that the pipes are squeezed but not shut off. The choice of flexibility in aluminium sheet and pipes and also the spacing between pipes is critical so that the pipes are squeezed tightly against the metal without being shut off. The metal is given an absorptive surface. Finally a glazing layer is placed above the absorber sheet and fastened securely. A crosssection of a portion of the collector is shown in Fig 1 below.