SUMMARY
The introduction of the concept of entropy in architecture has brought to light the tight bond that exists between the degradation of energy and the degradation of matter, shifting the focus to the daily energy consumption of a building during its lifespan, as well as to the cost, in energy terms, of constructing —or repairing— that particular building. In short, it has given way to two different approaches to understanding the impact of construction on the environment. The first approach refers to the kind of architecture that uses free energies generated from an efficient use of climate variables as a design tool. The second approach refers to the kind of architecture that, in its different variants, chooses to restore built heritage. The purpose of this article is to hybridise these two approaches to the impact of construction on the environment by examining architectural intervention on built heritage through the lens of thermodynamic principles. To this end we will review two contemporary interventions that have paradigmatically transformed old industrial buildings into new cultural premises. Far from applying standard intervention criteria, largely based on architectural language, context or programme, these restoration works follow design premises that are founded on energy exchanges with the neighbouring environment, and that are open to change. In a way, both exemplify how architecture can be understood as a “dialectics of entropic change”, as coined by Robert Smithson. From a stance of material and conceptual dualism that blurs the lines between past and present, energy and memory, both interventions generate memorable images. Their outward appearance, based on assemblage, hybridisation and contrast, both in terms of energy, form and matter, ultimately seeks to showcase the tensions and challenges inherent to the passing of time in architecture.