The Urania Villa is a small residence from the end of the 19th century that was the renowned astronomer Josep Comas i Solà’s home. The villa is one of the last existing urban examples of what was once the Farró neighbourhood in the Sarrià-Sant Gervasi district of Barcelona. The re-densification of the neighbourhood throughout the 20th century left the building and the surrounding small garden sandwiched between two imposing partitions. The new Equipment Complex takes on the challenge of giving new life to the villa and the existing gardens and incorporates it into a newly built building. The strong pre-existence of the villa establishes the level of the ground floor and the first floor. A double access to the plot allows to connect Zaragoza Street and Via Augusta, and at the same time it allows access with a route adapted to both the ground floor and the basement. An external staircase connects the whole new building vertically, a light and permeable element that gives air to the whole set. On the first floor, the terrace of the new building is joined to that of the villa, giving more transparency and ventilation to the pre-existing neighbouring estates that face the plot. Once rehabilitated, the Urania Villa becomes a meeting point, a multi-purpose open space equipped to carry out all kinds of activities as required by such a building. The extension, a tall, narrow building facing south-east with a large gallery, passively air-conditions the social and informal activity areas as well as the building's circulations. This intermediate space functions as a greenhouse in winter and as an umbrella in summer. It acts as a thermal cushion, separates the air-conditioned areas from the outside, and reduces the energy demand of the building. The façade adapts automatically to the external conditions. Interior temperature sensors act on the glass façade, opening or closing it as needed. Outdoor probes measure solar radiation and act on folding shutters. The indoor plantation formed by different species provides a pleasant feeling of freshness in summer, while in winter it reduces its volume to allow to capture the solar radiation. The building envelope has been designed to achieve low thermal transmittance, minimise thermal bridges and a high level of tightness. The building also stands out for the intensive use of materials with a low environmental impact, quickly renewable and of recycled origin: auxiliary structures and wooden carpentry, mixed wood-aluminum curtain walls or hemp insulation, among others. The Villa Urania Equipment Complex has been designed as an almost zero energy building (nZEB). Its energy consumption is very low and most of the energy needed is produced in the building itself. High efficiency active systems have been chosen. The building has a geothermal heat pump supported by 11 wells distributed throughout the plot that provide heating, cooling and domestic hot water. The lighting of the whole building is LED, and on the roof there is photovoltaic production with 19kWpic installed. A 20,000L buried tank allows rainwater to be collected and used in a closed circuit to irrigate the building's plantation.