I think you're on to something. From this article:
Maeshowe The megalithic mound
it appears that the entrance was illuminated by the setting sun for 22 days on either side of the solstice. So the sun was a "refrigerator light" just before suppertime in the winter. Another article reported that the passageway sloped up toward the interior, so melting ice could drain. The ditch around the outside reminds me of the "French" drains around my house. Some possibilities:
1. The main chamber was used to store meat. The recesses might have held extra ice collected during the winter.
2. The structure was used to store grain and vegetables. The recesses might have been large silos, if the usual small in-ground silos were not used.
3. This was used to store the community supply of beer, and the sun announced "happy hour".
Whatever the purpose, are some of the mysterious stone rings elsewhere just incomplete "frames" for similar structures? Is Stonehenge just a neolithic boondoggle that could not be finished?