## 5 Results and Discussion  
TRNSYS model runs for the time span of summer months i.e., from April to September. As not enough exploratory information exists from a real framework, the current simulations are compared with the already published results for validation of the current model. [PERSON] and [PERSON] [25]  
Figure 6: Cooling load profile. found in their study that the best tilt angle plays an extensive role to expand the output of a solar collector. The determination of the optimum collector slope is influenced by using many limiting factors, such as deficiency of manpower body and inaccessibility of the region of solar collector subject due to which normal tuning of the slope is mostly not feasible. So, in our model, the greatest seasonal SF is acquired for the area at which 50% PES is achieved with an optimum collector slope of 9\({}^{\circ}\) for evacuated tube collector (ETC) and 15\({}^{\circ}\) for a flat plate collector (FPC) as shown in Figure 7.  
Storage sizes are plotted for collector areas of FPC in Figure 8 at which flow schemes are realizing 50% seasonal primary energy savings. It is essential to note that the legends in Figures 8 and 9 are representing the area of collector in m\({}^{2}\) used for one of the flow schemes of the study. For instance, legend 510 S1 means that 510 m\({}^{2}\) collector area used for flow scheme 1. Similarly, all other legends in Figures 8 and 9 have same syntax. It can be observed from Figure 8 that with increasing storage capacities, primary energy saving first increases, then start decreasing afterwards. For FPC, collector area of 635 m\({}^{2}\) with 30 m\({}^{3}\) storage tank volume is required for achieving 50% PES with S-1 while collector area and storage tank volume is reduced to 550 m\({}^{2}\) and 20 m\({}^{3}\) respectively, is used for saving 50% of primary energy. In S-3, an optimized volume (10.2 m\({}^{3}\)) with a comparatively small collector area (than S-1 and S-2) is used to achieve the target of 50% primary energy saving. Similar trends are obtained for ETC as shown in Figure 9, however, the requirement of the collector area and storage tank size was greatly reduced because of the higher efficiency of the ETC [26]. With S-1, 128 m\({}^{2}\) collector area and 3 m\({}^{3}\) storage tank, while S-2 simulated with reduced storage size of 2 m\({}^{3}\) and 112 m\({}^{2}\) collector area to get 50%  
Figure 8: The trend of storage sizes for flat plate collector (FPC) areas of 50% PES for all flow schemes. Figure 7: Optimum slope of solar collectors. saving of the primary energy. A collector area of 93 m\({}^{2}\) was required to achieve 50% primary energy saving with scheme 3 of the current study with an optimum storage capacity of 15 L/m\({}^{2}\) (1.4 m\({}^{3}\)). The reason for decreasing PES with increasing storage sizes is that the higher tank sizes require more time to increase the tank's average temperature so that more auxiliary energy will be consumed and for a longer span of time to heat up the colder intake of tank's outlet. This is also the reason that S-2 would perform better than S-1 because S-2 diverts chiller's outlet flow to the auxiliary unit when it is hotter than the tank's outlet so that less auxiliary energy consumption as compared to S-1. In Figures 10 and 11, the seasonal variation of the fraction of energy-saving with collector areas of ETCs and FPCs to fulfil the cooling demand for all flow schemes is demonstrated at their optimum conditions. S-3 returns higher energy saving for ETC and FPC and S-1 yields less energy saving. The trend in Figures 10 and 11 is explained by Figures 12 and 13, in which an area of 93 m\({}^{2}\) is selected with their optimum storage sizes and collector's tilt of each scheme and simulated for the month of June. The results of a typical day of the summer season is plotted (3960-3984 h), in order to comprehend the fact that how schemes S1, S2 and S3 are acting in descending order of their primary energy-saving trend. Figure 10: PES vs. ETC area.