Great architecture exhibitions are few and far between. The fundamental problem is obvious: unlike most art shows, you can rarely display completed work. The best you can hope for is some representation of architecture — a simulacrum that seldomly evokes the spirit of the original.

Many exhibitions end up highlighting the architectural design process, which creates its own difficulties of distance and alienation. You end up asking visitors to read about — and imagine — architecture rather than experience it.

Although people are interested in buildings, they are disinclined and often unable to read architectural plans. Texts, presentation drawings, models and photographs can help but they, too, are forms of documentation that must be studied. Architecture is not pictorial but spatial. Even the most elaborate computer simulation or film is a poor substitute for three-dimensional experience.

The unusual proposition underpinning Practising Architecture: Five Architectural Projects, an installation at the Royal Hibernian Academy (RHA), is to present, rather than describe, architecture as a direct experience to an art audience. The exhibition offers an opportunity to experience an aspect of architecture that sets it apart from building — its art.

The idea for the exhibition grew out of a conversation two years ago between the RHA director Patrick Murphy, the curator of Practising Architecture, and Paul Kelly of FKL Architects, on the relative natures of art and architecture and areas of overlapping concern between both disciplines.

At Murphy’s instigation, FKL developed an organisational framework for the exhibition in which five of Ireland’s most dynamic emerging architectural practices — Heneghan Peng, Boyd Cody, Hassett Ducatez, FKL and Dominic Stevens — have been invited to speculate about the exhibition of architecture.

As the content of Practising Architecture is not art, the gallery walls have been left bare. A structure with the scale of a building (large enough to command the huge area without filling it) is placed eccentrically within the space. Five chambers are marked out by six parallel walls, set about three metres apart.

This big move recalls, as Murphy readily acknowledges, the spectacular impact of the half-size mock-up of Kevin Roche’s unbuilt orangery — an eroded hollow cube — in a notoriously difficult space, the Douglas Hyde gallery, during the 1983 exhibition that celebrated Roche’s Pritzker prize.

Grainne Hassett turns her back on traditional architectural space altogether, suspending a white cube perforated with spy holes that reveal a mirrored interior. Based on her current research into visual perception and optics, Hassett manages the conjurer’s trick of somehow floating colours in space.

Roisin Heneghan and Shih-Fu Peng’s contribution is the most conventional of the five: they simply show one of their projects. Like some gallery exhibit, a backlit rendering of the monumental facade of their Grand Museum of Egypt is mounted in a linear band at eyelevel, opposite a strip of mirrors. However, parallel reflected images and a projected animation in a black room are not enough to transform the space between the walls into part of the exhibit.

Dominic Stevens creates an allegorical playground of spatial opposites: a dark, coloured maze of densely packed columns supporting an empty, open-top, bright-white box.

Peter Cody and Dermot Boyd had not expected their ramped and roofed installation, with its play of perspective and compression, to trigger discussion of language in architecture, one of the key international topics of the past 50 years.

“Visitors said they had a sense of recognising it,” says Cody. “Architecture is a lived experience: there are memories that spatial experience can engender, like an index, which allow us to navigate the world.”