Evaluation of Energy Codes for Buildings and Building Performance Rating Systems in India
Policy making for sustainability in the built environment in India is presently in a decisive period, the outset of an imminent rampant growth phase in both the commercial and residential sectors. In the commercial sector, it has been estimated that 70% of the office space in India that will be available in 2030 is yet to be constructed. Moreover demand for office space is expected to increase by up to fourfold in the short term. The Bureau of Energy Efficiency, a statutory body under the Ministry of Power of the Government of India launched an energy code targeted at new commercial build in the country called the ‘Energy Conservation Building Code’ or ECBC to set a standard for reducing electricity consumption by the selection of efficient systems and materials. The code is currently available for voluntary compliance, and is expected to become mandatory in the coming years. The Ministry for New and Renewable Energy has fostered the launch of a national rating system (or a green building rating system) for the certification of overall sustainability in buildings called the Green Rating for Integrated Habitat Assessment or GRIHA. This study aims to evaluate the ECBC and GRIHA codes in the midst of similar existing codes and rating systems worldwide.
The evaluation of the ECBC was carried out by using whole building energy simulation in three cases. The base case was simulated using existing construction practices and materials from a building constructed in Mumbai. The next case was to simulate the electricity consumption if the building had complied with ECBC with all the prescribed parameters. Similarly the same building was simulated according to the ASHRAE 90.1 energy standard for comparison. The simulation was carried out using EnergyPlus engine using the Design Builder modelling application. The results show that the case complying with the ECBC shows significant reduction in electricity consumption, specifically in lighting and cooling consumption.
The evaluation of GRIHA was done through a comparison with the LEED and BREEAM rating systems. The multi criteria decision analysis technique, Analytical Hierarchy Process was used to determine the most suited rating system for the Indian context from a range of sustainability criteria. The GRIHA rating system showed superior emphasis on Energy Efficiency and Water Efficiency criteria thereby ranking itself higher than the other rating systems in comparison. Criteria where GRIHA shows deficiency have also been identified through the ranking in the Analytical Hierarchy Procedure.
The results of the study make a case for the immediate enforcement of the ECBC and for the advancement of the GRIHA rating system.