Conduction-based charging maps for latent heat storages

Abstract

Charging of latent heat storages is hampered by the low PCM thermal conductivity. Moreover, the lack of design rules for LHSs complicates the development of commercial compact storages. In the present work, the combined charging power and storage density is presented for PCM storages enhanced by highly conductive aluminium fins, charged by a water flow with a finite total heat capacity, and dominated by conductive heat transfer in the PCM. The performance maps are valid for low temperature differences and small PCM enclosures, as for such designs effects of natural convection can be neglected. We show that the overall storage performance can be estimated from a unit cell approach which greatly reduces the computational effort. Moreover, reducing the individual compartment height as well as slowly and simultaneously charging the individual cells is demonstrated to be effective for increased charging performance.