The display of the velocity profile was completed in Figure 3. Velocity was observed to increase with the longitudinal length and then decrease as it gets closer to the top of the collector. This can be explained by the accumulation of hot water at the top of the collector reducing the velocity boundary layer and promoting diffusion of heat with time. A horizontal plane would show that high velocities occur at the absorber plate where high temperatures take place. It is observed in Figure 3 that an increase, followed by a decrease, pursued by an increase in velocity occurs between the fins. This decline in velocity in the middle of the fins suggests the addition of fins to increase the velocity magnitude. The horizontal view of velocity profile supports this observation.

7.43Є-03 7.06e-03 6.69e-03 6.32Є-03 5.95e-03 5.57e-03 5.20e-03 4.83e-03 4.46e-03 4.09e-03 3.72e-03 3.34e-03 2.97Є-03 2.60e-03 2.23e-03 1 86e-03 1.49e-03 1.11e-03 7.43e-04 3.72Є-04 O. OOe+OO

Results showed that the overall velocity increased with time until it reached a peak value from which velocity magnitude declines with the passage of time. The increase is due to a high heat flux through the fins to the water occurring after the initial capacitance effect of the system. With time, hot water builds up at the top of the collector resulting in a decline of heat transfer and therefore heat is diffused from the system.

Figure 4: Longitudinal water temperature stratification — 4 fins, side view, after 20mn

In an attempt to improve the heat transfer one fin was added to the original ICS-SWH design. New 3D velocity and stratification analysis were undertaken for the five fin ICS-SWH.