Example The example refers to a north-south facing catenary tent collector deployed on the Martian surface [6] at the location of Viking Lander VLI (Latitude - 22.3°N, Longitude - 47.9°W) and in an autumn day Ls = 200° [6], For this time of the year eq. (3) does not apply and, therefore, only side B will be partially shaded during the day. The dimensions of the catenary collector are: D = 3m, H = 2M and L = 1.5m. Since fc(0) = H, this results in k = 2.53 and the catenary equation is given by: Figure 10(a) shows the shadow shapes on side B of the catenary collector for 0 = 22.3°N for different hours of the day. The shadow calculations are based on section 2. For comparison, the shadow shapes for 0 =32° are shown in Fig. 10(b). As expected, the self-shading effect is more pronounced for higher latitudes. It is interesting to note that for 0 =22.3°N, the shadow effect is quite small during the noon hours. In summer, the shadow will be even less. The insolation of the catenary-tent-collector for 0 =22.3°N, Ls=200° and albedo al=0.22 is shown in Table 1 based on radiation data at VLI [6]. The table shows the beam, diffuse and the albedo insolations on sides A and B in kWhr-day and kWhr/ m2-day. As expected, the beam insolation on side B is lower by 59.6% than on one side A. It is interesting to note that the diffuse insolation comprises 46.6% of the global insolation. This characteristic is typical for Mars, a place where the atmosphere consists mainly of dust particles.
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