FROM THE REDRAWING OF THE PAPYRI TO THE PARADIGMS OF PASSIVE VENTILATION IN ARCHITECTURE

Amongst the papyri found in a former dump near Oxyrhynchus in Egypt (current el-Bahnasa), it has been unveiled one on which it is drawn a ‟Groundplan of a house made in the second century BC” (fig. 1a). In the horizontal section of which seems to be a living space, exposed to the public for the first time in 1957 at the Ashmolean Museum of Art and Archaeology of the University of Oxford, it is recognisable its originality compared to other contemporary representations [1]. In the plan there are three main areas: the central one, interpreted in archeology as the atrium [2], plausibly typified a hypothetical impluvium for rainwater harvesting. Behind the tank-cistern a flight of stairs (because of the row of parallel segments) that lead to the basement, could be a vaulted cellar carved in its enclosure. Contiguous to the same tank is instead represented a rectangular space, a sort of cavaedium (courtyard), given the proportions and 2the blindness of three of its sides (fig.1b). Why this small area existed is the reason for this study: it is questioned what it served for, or rather what it represented within this perfectly proportioned and detailed floor plan.
Helpful hints can be obtained from another papyrus (fig.2), which is part of the collection known as the Book of the Dead [London, British Museum] attributed to Nakht, royal scribe and superintendent of the army who lived at the end of the Eighteenth Dynasty (1543-1292 BC). The coloured elevation in its right end evidences two curious and equally oriented triangles. Similarly, but opposite to each other, they appear in the fresco that decorates the tomb of Nebamun (fig.3), an official who lived during the reign of Pharaoh Amenhotep III (1387-1348 BC). Graphic processing of this detail has addressed the research for archetypes related to the Theban house [3]. However, the exact functional interpretation of those forms was obtained by observing the clay house models, recurrently found in the tombs (fig.4). These are meticulous scale reductions, considered the religious function they have to serve, in which those characteristic triangular projections appear as geometric idealizations of a recurrent detail, recognized by the experts [4], elements with hollow bodies aimed at the capture of breezes, in other words systems of passive ventilation which, without the use of energy, air-conditioned the indoor environment of the houses in that distant era.