Reliability analysis and condition-based maintenance optimization for a warm standby cooling system

Coolers are critical components in various industrial systems, which can effectively mitigate temperature-induced failure risks. In this paper, we investigate the reliability analysis and maintenance optimization approaches of a two-unit warm standby cooling equipment. The working conditions of both coolers have significant influence on the temperature variation of the target system. When at least one cooler is working normally, the temperature rises slowly (represented by a small degradation rate); otherwise the temperature rises sharply (represented by a relatively large degradation rate). We use a multi-stage Wiener process to characterize the degradation trend of the system. The reliability function of the system is formulated, and accordingly a condition-based maintenance policy is developed based on temperature monitoring information. The maintenance cost is minimized via the joint optimization of the temperature control limit and age threshold. A case study of an enclosed busbar with two coolers is given to illustrate the application of the proposed model.