heat_storages do not stack in the inventory, thus heavily polluting it.

Every Heat Storage component has its own durability, thus it should be treated as a tool. Does any tool stack in inventory? No. This is an intended behavior since the beginning of time. Also see image.
** Minecraft 1.4.7 with give command displaying in chat.

P.S. Also could you please use discord for such questions? They do pollute github issue tracker.

ok