Promoting induction heating – steam generators for medical sterilisation

Abstract

Saturated steam sterilisers are one of the most energy consumers in hospitals. Induction heating (IH) could be one of the energy saving solutions considering its proven potential in industrial applications such as steam generation (SG) and pasteurisation. Hitherto, there are no studies in literature about this field except one for dentistry. In this review paper, we aim to investigate valuable energy efficient guidelines for designers to promote IH steam generators integration in the medical sterilisation. To do so, we conduct an energy flow analysis based on a process-oriented decomposition. We then detail the previously identified guidelines through a review of the literature on IH-based liquid heating and analyse them throughout the paper. Many key points protrude therefrom: "inductor-susceptor/water" interactions are decisive especially susceptor shapes. A package of susceptor shapes exposed in this paper can be considered. Back heat transfer from the susceptor to inductor is important too. Frequency and turbulence has opposite effects, so should be given the utmost attention. Inductor losses need to be reduced via coil wrapping, water cooling, and multi-coil design for high powers. The energy efficient design of the susceptor includes stray magnetic fields, geometry of the susceptor, skin depth, and the effect of electromotive force due to eddy currents. Susceptor-inductor coupling is relevant too. Finally, the optimisation of thermal transfer to water involves insulation, frequency, discharge losses, turbulence and susceptor shape. Based on these parameters, good designs can be put forward to launch prototypes and explore fully IH opportunities in this field for more energy efficient sterilisers.