EN 15193, Lighting Energy Numeric Indicator: LENICALC calculations in a retirement home case study

The EN 15193 standard allows the evaluation of energy requirements for artificial lighting of buildings and the calculation of “Lighting Energy Numeric Indicator” (LENI); it belongs to a general structure which includes all the standards regarding the energy efficiency of buildings in Europe. In Italy a free software tool called LENICALC has been developed, which allows to calculate the LENI according to comprehensive method of the standard. The UNI PdR 77/2020 document has also been published to guide the user of LENICALC in the setting up of the calculation, and, consequently, to apply EN 15193 standard. In order to apply and to test the full procedure, a case study has been selected, consisting in a block of a retirement house building, for which a simulation of baseline and retrofit of the lighting system is proposed. The baseline is a traditional fluorescent-based lighting system; the retrofit leads to a LED-based system, more energy efficient and with better comfort for the occupants and the working personnel. The block consists of a series of inpatients rooms, with private bathrooms and balconies, where guests live, and a corridor: daylight contribution is provided by doors and windows. The LENIsub (i.e. the indicator applied only to a part of the building) has been calculated for the baseline and retrofitted situation, taking into account - as required by the standard - a number of parameters, related to occupancy, daylight, controls, installed power, emergency and standby power. The assessment of the energy saving due to the retrofit is then based on LENIsub improvement of the block, and a detailed analysis of the individual parameters which influence the energy consumption is given. During the work, a series of interpretation items of the standard, not yet considered, have been identified, solved and some improvements to the software have been implemented.