An approach for calculating lighting energy saving potentials in the office buildings on the basis of LENI data

Energy performance of the lighting systems is considered in the related European standard EN15193 for the evaluation of the amount of energy used for indoor lighting of the building by providing a lighting energy numeric indicator (LENI), which is a very useful indicator in terms of energy performance. Although very sophisticated data of the building is being used for calculation of LENI, it does not give clear information on possible energy saving potentials and the systems, which could be applied to save energy. This study focuses on the existing office buildings in order to define a new approach for calculation of energy saving potential based on LENI data. By modifying lumen method, which is easy applicable and useful for indoor lighting calculations, installed power could be analytically expressed as a function of room utilance and luminaire efficacy factor where other required parameters such as room dimensions and functionality could be achieved from LENI database. As a result, a new indicator LESI (Lighting Energy Saving Indicator) for expressing lighting energy saving potential has been introduced and a computer software "bep/ETA" has been developed.