Solar walls, glazed solar collectors, and so-called Trombe walls are all different types of passive solar heating technologies based around the use of materials meant to absorb solar radiation (generally, dark-colored materials since dark colors absorb the heat better) and thermal mass. The end goal is to provide space heating, and often ventilation as well.
The means by which this space heating occurs varies by design. Glazed solar collectors work similarly to solar thermal water heaters — as external structures that absorb solar radiation as heat and then redistribute it. A Trombe wall, on the other hand, is located in the building itself, usually right up near a glass window and outfitted with or without a venting system.
Unglazed solar collector heaters are another variant — one whereby sheets of dark perforated metal are used as external on building walls where solar gain is good — but they are usually just used to precondition air before it is drawn into a ventilation system (thereby improving system performance and cutting costs).
As you’ll note, such approaches to passive solar heating are broadly similar to those we discussed in our earlier article about passive solar house design.