Authors: Padmini Rajaram, Rajan Rawal
Abstract:
Indian Standard Time (IST) is calculated with reference to 82.5° E longitude and the difference of +0530 hours from Greenwich Mean Time (GMT). The permanent advancement of IST was proposed in the previous study from +0530 to +0600 hours with reference to 90° E longitude and is estimated to 16% of savings in peak load electricity demand by analyzing all the power consuming sectors such as industrial, agricultural and commercial sectors of India. The present study aims at quantifying the savings in lighting energy consumption for office buildings, due to the permanent advancement of Indian standard time from +0530 to +0600 hours (GMT).The study initiates by walk through energy audit to evaluate lighting load details and occupancy details for two cities; Ahmedabad in the west and Kolkata in the east of India, which are 64 minutes distant from each other. The audited data is used as input parameters for reference models that are modeled using design builder with energy plus platform to determine annual energy consumption for lighting in office buildings. The time advancement in this study is analyzed by evaluating shift in occupancy schedules for offices. Hence parametric combinations of occupancy schedules of 1000 -1900 hours versus 0930-1830 hrs, and 0930-1830 versus 0900-1800 hrs are examined for varying floor plate sizes of 100m², 400m², 800m² and 1200m², with varying aspect ratios, window wall ratio and lighting controls. Further one reference model is simulated to evaluate the savings in lighting energy consumption for all the major cities in India. Results from the simulated models show an average of 6.27% savings in the annual lighting energy consumption for office buildings in all major cities, due to the advancement of time or shift in occupancy schedule, given that linear lighting controls are applied for all the above models. It is also observed that office buildings in eastern India benefits 2% more than the west.
