Initial Capital Cost

Initial capital cost is the direct capital cost accrued at the time of purchasing. In this chapter, the direct optimization measures have been compared to evaluate each and find out the most suitable solution, as can be seen in Figure 11.7.

It can be seen from the physics discussed previously and according to the simulation outputs that increasing WWR has a substantial effect on increases in luminous flux as compared with VLT. But, according to Figure 11.11, the cost incurred decreases with increased VLT whereas, in the case of WWR, it increases substantially.

Thus, Figure 11.10 provides a cost comparison of all possible solutions obtained from the simulation (tabulated in Table 11.4). The cost of glass has been sourced from Saint Gobain.

Moving on to passive techniques (Section 4.2), the cost of implementing these techniques is expressed in rupees per meter squared (Figure 11.12).

It can be seen that the highest cost is incurred in the case of the light pipe, which costs approximately Rs. 37,800/m² . Also, the cost of the light shelf is much higher, costing approximately Rs. 9450/m² compared with the cost of optimizing WWR, which is approximately Rs. 550/m².

It can be seen that increasing WWR escalates the cost of improving the indoor environmental conditions to Rs. 4,061,728 from an initial amount of Rs. 1,205,627, which financially is not a feasible and practical option (Figure 11.13). Also, lower VLT glass is high-performance glass, as seen in terms of thermal loads; hence, it is expensive.

FIGURE 11.11

Cost analysis of increasing WWR and VLT.

FIGURE 11.12

Cost comparison of light shelf, WWR, and light pipe.

An increase in VLT also does not cause any increase in the cost of optimization; however, as can be seen from the results discussed previously, increasing VLT in this case does not suffice the requirement.

Increasing the glazed area (WWR) to the maximum limit possible helps in achieving the desired luminous flux through daylighting but, on the other hand, it also increases the cost of optimization as observed in Figure 11.13.

FIGURE 11.13

Cost comparison of proposed feasible VLT and WWR solutions.

Thus, it is essential to figure out the most technically and economically feasible solution, which could be a combination of identifying the most feasible options along with satisfying the objective to achieve a desired luminous flux through daylighting, and also financially viable for the user.