Lumen degradation effect on fluorescent-to-LED switching: techno-economic viability for a lecture room

Abstract

Efficient illumination of classrooms is one of many technologies that can help in constructing a cleaner future and have a positive environmental impact. However, the long-term economic plan of their implementation must still be created and validated. One promising technology is light-emitting diodes (LEDs) that have a low carbon footprint compared to conventional lighting sources. However, different studies barely mention lumen degradation, which is reduction in the illumination capacity throughout LEDs’ lifetime. This paper investigates whether it is economically viable to switch fluorescent lamps to LED lamps while considering lumen degradation of both technologies, by considering the study case to be a classroom of a Kazakhstani university. The performance assessment was based on life-cycle cost analysis (LCCA). The required luminosity level, model lifetime (13 years) and classroom layout were the same for both technologies. The software RETScreen was used to develop the energy model and LCCA and the risk assessment of financial parameters. Simple and equity payback periods were found to be less than half of model lifetime with the internal rate of return reaching 20% and the electrical energy expenses decreasing by 10.95 kWh per year per m² of the classroom, i.e., over 35%. The greenhouse gases (GHG) emissions dropped by 4.38 kgCO₂ eq. per year per m² of the classroom, which is over 30%. This analysis supports the advantages of using LEDs instead of fluorescent lamps, as a financially favorable decision that also reduces GHG emissions despite the high lumen deterioration of LEDs.

Graphic abstract