Figure 6 shows a 0.7-m-diameter collector (capable of delivering 600W at 350°C). The collector was sourced locally for testing.

After acquiring the collector, 250 mL of engine oil was heat to see what temperatures were possible to attain. Oil was chosen because of its high boiling point, its relatively high heat capacity (2500 J/kg. K) and its easy of availability. After heating for 15 minutes, the base of the flask holding the oil reached 180°C, and the oil within the flask reached 165°C.

Feeling confident we could meet with success, we attempted to fit the solar collector directly to the bubble pump, as illustrated in Figure 8. The size and location of the bubble pump made this difficult.

A system was required to move the heat from the focal point of the collector to the bubble pump. A simple copper pipe filled with oil was used (see Figure 9), and because the heated oil would move into the bubble pump through buoyancy there was no need for an external pump.

Insulation was fitted, as shown in Figure 10, to ensure the heat collected by the pipe and oil did not escape before entering the bubble pump.

Figure 11 shows the complete system with the solar collector and the insulated copper pipes in place. With the solar collector on the ground, tests were performed.