Energetic Characterization of Building Evolution

The constant growth of the building sector has had a deleterious environmental impact across the world. Technological advances, the use of new materials and the replacement of traditional construction systems with industrialized ones have resulted in significant growth in the Total Embodied Energy of buildings in Latin American countries. In the last few decades, Ecuador and its four geographic regions too have experienced this change. In this context, this study focuses on analyzing the change in construction systems in the Andean region of Ecuador from 1980 to 2020, and studying the impact that this change has had on the Total Embodied Energy of residential buildings. The first part of this study provides a detailed conceptual framework of the subject of this study, and discusses the importance of energy, and its production and consumption, in Ecuador in the last decades. The second part analyses the changes in construction systems that this region has witnessed according to national censuses. This information is contrasted in the results section where 40 houses built in the period of analysis in the city of Cuenca-Ecuador are analysed. The growth of embodied energy in dwellings in this region in recent decades has been 2.15 times. Within this increase, the most significant component has been the Structure, followed by the Envelope and the Finishes. Finally, the results show that the changes in materials used have had consequences not only at the environmental level, but also for the thermal mass of the Envelope, which can affect the interior behavior of the building.

The introduction of new technologies and materials in recent decades has significantly reduced construction times around the world. These changes have brought about a standardization of construction systems, which don’t account for different cultural, social or even climatic contexts. Ecuador, and all its regions, have conformed to these changes, leaving behind their vernacular architecture which had been made of mud or guadua cane, and replacing them with industrialized systems which use materials such as concrete or metal. However, it is not clear whether these changes have been advantageous or disadvantageous for the interior thermal performance of the buildings. In this context, this chapter presents a thermal analysis of the different construction systems used in housing projects built in the last 4 decades, viz. 1980–1990, 1990–2000, 2000–2010 and 2010–2020, taking as a case study the Andean region of Ecuador. For this purpose, 10 dwellings from each period have been analyzed, and the average characteristics of their materials (Envelope weight) and the building morphologies (window/wall ratio) have been established. The impact of these variables on the interior temperature has been measured through energy simulations with the Design Builder program and its calculation engine Energy Plus, which has been configured to a base model for the four periods, in order not to bias the results. The study establishes that residential buildings in this region have, on the one hand, seen considerable reduction in the weight of their envelope, and on the other hand, seen considerable growth in the proportion of the glazed surface. These changes have had repercussions the thermal oscillation in the most recently built buildings tends to be greater than in the older ones, as the morphological and material changes results in a reduction in thermal mass and an increase in thermal transmittance.

The construction industry has for many years been a cornerstone in the world economy, and serves as a reliable indicator of a country’s economy since its evolution is pro-cyclical, i.e., it behaves just as the total production does. This chapter focuses on the impact of the Ecuadorian construction sector’s performance on the GDP, as well as its possible relationship with the energy consumption. Hence, this study examines construction, economic, and environmental variables in the Ecuadorian context. With this objective, different indicators such as the GVA, energy demand, and electricity consumption have been considered and compared, during the period from 1997 to 2020. The analysis uses Pearson's correlation coefficient to measure the statistical relationship between the variables. The results confirm that the increase in Ecuador's economy is directly related to the increase in the construction sector, which in turn has a direct influence on the energy expenditure and consumption by different sectors, and specifically, by residential buildings, which shows a directly proportional dependence. In other words, the increase in the country's economy generates a greater amount of construction, which in turn consumes more energy and therefore, is more environmentally polluting.

The materiality of architecture is an inescapable issue when it comes to building, however, throughout history there have been few examples that focus on its expressive possibilities. Materials can be seen as the ‘pixels’ of architecture, and are what allow us to create spaces, geometries and textures, but at the same time they are also elements with mechanical and physical characteristics that generate structural systems and thermal comfort in interiors. In addition, the environmental implications of the costs of extraction, transformation, end use and disposal are enormous, since the wrong choices can saturate the planet and, in some cases, affect health. Industrial modernity has produced a huge number of new materials from the oil and chemical industries, relegating traditional—and much more sustainable—materials to the background. The study of ancestral vernacular systems allows us to appreciate the development of techniques through trial and error that allow buildings to adapt and interact with their environment. The teachings contained in the examples that still survive allow the modern designer to be inspired towards a more sustainable approach, and can also generate modern interpretations. This has increased with the contemporary development of new systems and materials within the field of bioconstruction, a field that, though still in its infancy, has already resulted in some innovations of great interest. Integrating sustainable materials in modern projects is an exercise in responsibility, which offers the opportunity to investigate its sensory possibilities through its exposed and solid use, without coatings. Therefore, working with constructive clarity and using bioclimatic materials allows the building to connect with memory, the context and respect for the environment, as well as generating evocative atmospheres full of meaning.

Historical materials can be studied from various technical, symbolic, artistic, health-related and other perspectives. This process points to a constant versatility, in which conservation goes beyond the conventional spheres of its management, such as inventory. In the case of the buildings in the Historic Center of Cuenca (HCC), construction materials are studied for historical and architectural perspective, to ensure maintenance and even to inform contemporary design. Thus, the type of material becomes the analytical axis to study the architecture of buildings that trace their origins to the Cañari, Inca, European and American influences through social and cultural interactions. Through the study of three materials (adobe, stone and brick), it is possible to define the energetic implications of their production and use, as well as understand the requirements for their architecture conservation or rehabilitation, thus making it possible to assess the relevance of the interventions and management policies in force. Therefore, a solely historical-artistic, physical–mechanical or chemical vision is not sufficient, as the interest comes from perspectives of resource efficiency and articulation of cultural meaning. Today, this interest is positioned within the framework of the Sustainable Development Goals.