Lighting retrofit and maintenance models with decay and adaptive control

In lighting retrofit projects, a lamp population is subject to decay, which results in significantly deteriorated energy efficiency (EE) and reduced cost saving. Incremental retrofit and maintenance are studied to overcome the decay in the population, so that EE performance can be sustained. Current models of natural decay cannot reflect the interactive dynamics of incremental retrofit and maintenance, so a new decay model is proposed for these interventions. Using a control approach, a multiple‐input and multiple‐output state equation is formulated. Adaptive control laws are designed to cope with unknown parameters of the proposed model, and to achieve stable performance improvement. This new model is verified, based on empirical data, and the results of adaptive control indicate that the number of working lamps can be maintained as a required value.