D
Dragoon
Theres nothing temperamental, special or complicated with a thermal store. Without having multiple inputs though it will cost you an arm and a leg maintaining sufficient temperature in the thermal store for your requirements.
I did my research on thermal stores a couple of years ago, but I remember vaguely something about issues with the mixing with cold water after the hot water's come through from the heat exchanger. Also heat exchanger problems as well, but the ol' memory's not too good so couldn't say for certain. But I do remember being impressed by them!