On aging components impact on multi-state water cooling system: Lz-transform application for availability assessment

Modern high-tech medical equipment requires precise temperature control and effective cooling, which allow medical equipment to be operated for longer periods and increased in availability of the equipment to patients. This paper presents the application of the L_z-transform method to availability assessment of aging multi-state cooling system for MRI equipment. The cooling system consists of 4 principal subsystems: chillers, heat exchanger, pumps and electric board. The performance of the system and the sub-systems is measured by their produced cooling capacity. Heat exchanger and pumps are aging components. MRI cooling system is working under constant demand, which determines by the types of MRI scans, shared between several medical departments. Straightforward Markov method applied to solve this problem will require building of a system model with numerous numbers of states and solving a corresponding system of multiple differential equations. L_z-transform method, which is used for calculation of the system availability for this cooling system, drastically simplified the solution.