Abstract
In a 1-out-of-n: G cold-standby system, one component is online and working with the remaining (n - 1) components being unpowered and waiting in the standby mode. The system fails when all the components have failed. In the case of non-identical system components, the sequence of putting the cold-standby components into operation can affect the system energy consumption greatly. Therefore, in this paper, we consider the optimal standby element sequencing (OSES) problem for the 1-out-of-n: G heterogeneous cold-standby systems with the objective to minimise the expected total system energy consumption. An analytical method is first proposed for obtaining approximate estimates of the total energy consumption of the considered cold-standby system. The method also provides a solution for evaluating the reliability of the 1-out-of-n: G heterogeneous cold-standby systems without the limitation on the type of time-to-failure distributions. Based on the proposed energy consumption analysis method, the OSES problem is solved. The brute force approach is used for obtaining the optimal initiation sequence for systems with a small number of standby units; an optimisation methodology based on genetic algorithm is implemented for systems with a relatively large number of standby units. Application of the proposed methodology is illustrated through several case studies.