Russian Fireplaces are a variant on the thermal mass masonry stoves. In fact the name 'Russian' is rather a misnomer as they are generic throughout parts of Eastern Europe and America. The fireplace and chimney are constructed with a serpentine path of baffles to direct the flue gases through the thermal mass of the stove.
Unlike the masonry stoves constructed in modern day North America these traditional stoves are a more natural evolution of the open fireplace. Typically they have a fairly small open hearth and a comparatively heavy and oversized brick chimney. As with modern masonry stoves the hot flue gases are channelled through layer after layer of brick and tile ducting where the heat is absorbed and later released back into the building.
The chimney was usually constructed in the centre of the building so that rooms on upper floors adjacent to the brickwork get the benefit of the heat. In this way one single, central, fire was able to heat a whole dwelling.
They have the aesthetic appeal of an open fire and approach the efficiency of the more modern masonry stoves. The open fire is probably the weak link as they are inherently less efficient than closed fireboxes. While the actual combustion process may be very efficient, the warm stones of the chimney setup a strong draft even when the stove is not in use. This forces warm air from inside the home up the chimney, which must by necessity be replaced with cold air from out doors.
The modern masonry stove usually has a tight fitting door and air control which reduces heat losses in this manner.
In this video (please excuse the somewhat rambling tour round the whole room - this is not my own footage!) you can see how the fireplace has become more than just a heater.
There are shelves, nooks and crannies for cooking pots and the like.
A combination cooking hearth such as this would likely have been the hub of any busy home, particularly in the cold of winter.