The invention includes a dynamic storage device requiring periodic refresh and including logical operation circuitry within the refresh circuitry. Each one of the plurality of heat exchangers provides the means for transferring energy between the phase change material on a primary side of the heat exchanger and a fluid on a secondary side of the heat exchanger. The circuit monitors characteristics of the AC power signal driving a known load and characteristics of the load or other elements and determines the duty cycle of the pulse width modulated signal, PWM, based upon the duration and amplitude of the over-voltage, over-current, over-limit or other event. The moving mechanism moves the holder between a mounting position where to mount the recording medium on the recording andor playback section and an dismounting position where to separate the recording medium from the recording andor playback section.