Reliability and cost analysis of the redundant design of a combined cooling, heating and power (CCHP) system

A combined cooling, heating and power (CCHP) system is a complex system with various devices and components. Reliability of the whole system has a relationship with reliability of each unit including power generation unit, heat recovery unit, space cooling generation unit and auxiliary unit, heat exchange unit, etc. The redundant design is a way to improve the reliability of the device or system. In this paper, the redundant design of the devices is adopted to a CCHP system. The k-out-of-n model is performed to calculate the reliability indices of the unit with redundant design and the reliability analysis of the whole CCHP system is presented. The unscheduled maintenance cost and downtime cost as a result of the failure occurred is analyzed in the total cost analysis of the CCHP system. The results present that the redundant design can reduce the total cost and improve the availability of a CCHP system within a certain capacity. The result of the sensitivity analysis indicates that the mean repair cost and failure rate strongly impact the cost of the system, however, the redundant design can reduce their impact on the total cost of the CCHP system. This result can provide valuable reference for the design and operational maintenance of the CCHP system.