The dynamic storage capacity of a periodically heated slab

The well-known problem of evaluating the dynamic heat storage capacity of a 1D slab is analysed extending the results to the more general case of periodic excitation profiles of any form. Equations in time and frequency domain to calculate the storage capacity are obtained and applied to some cases, showing that harmonic heating is not the most efficient way to store energy in finite and semi-infinite slabs. Quantitative comparisons show that, for slab of finite thickness, intermittent heating may yield up to 40% more heat storage capacity (and up to 52% for semi-infinite slab) than harmonic heating.