Ana Nadal

Urban planning and agriculture. Methodology for assessing rooftop greenhouse potential of non-residential areas using airborne sensors

The integration of rooftop greenhouses (RTGs) in urban buildings is a practice that is becoming increasingly important in the world for their contribution to food security and sustainable development. However, the supply of tools and procedures to facilitate their implementation at the city scale is limited and laborious. This work aims to develop a specific and automated methodology for identifying the feasibility of implementation of rooftop greenhouses in non-residential urban areas, using airborne sensors. The use of Light Detection and Ranging (LIDAR) and Long Wave Infrared (LWIR) data and the Leica ALS50-II and TASI-600 sensors allow for the identification of some building roof parameters (area, slope, materials, and solar radiation) to determine the potential for constructing a RTG. This development represents an improvement in time and accuracy with respect to previous methodology, where all the relevant information must be acquired manually. The methodology has been applied and validated in a case study corresponding to a non-residential urban area in the industrial municipality of Rubí, Barcelona (Spain). Based on this practical application, an area of 36,312m2 out of a total area of 1,243,540m2 of roofs with ideal characteristics for the construction of RTGs was identified. This area can produce approximately 600tons of tomatoes per year, which represents the average yearly consumption for about 50% of Rubí total population. The use of this methodology also facilitates the decision making process in urban agriculture, allowing a quick identification of optimal surfaces for the future implementation of urban agriculture in housing. It also opens new avenues for the use of airborne technology in environmental topics in cities.

Rooftop greenhouses in educational centers: A sustainability assessment of urban agriculture in compact cities

Today, urban agriculture is one of the most widely used sustainability strategies to improve the metabolism of a city. Schools can play an important role in the implementation of sustainability master plans, due their socio-educational activities and their cohesive links with families; all key elements in the development of urban agriculture. Thus, the main objective of this research is to develop a procedure, in compact cities, to assess the potential installation of rooftop greenhouses (RTGs) in schools. The generation of a dynamic assessment tool capable of identifying and prioritizing schools with a high potential for RTGs and their eventual implementation would also represent a significant factor in the environmental, social, and nutritional education of younger generations. The methodology has four-stages (Pre-selection criteria; Selection of necessities; Sustainability analysis; and Sensitivity analysis and selection of the best alternative) in which economic, environmental, social and governance aspects all are considered. It makes use of Multi-Attribute Utility Theory and Multi-Criteria Decision Making, through the Integrated Value Model for Sustainability Assessments and the participation of two panels of multidisciplinary specialists, for the preparation of a unified sustainability index that guarantees the objectivity of the selection process. This methodology has been applied and validated in a case study of 11 schools in Barcelona (Spain). The social perspective of the proposed methodology favored the school in the case-study with the most staff and the largest parent-teacher association (social and governance indicators) that obtained the highest sustainability index (S11); at a considerable distance (45%) from the worst case (S3) with fewer school staff and parental support. Finally, objective decisions may be taken with the assistance of this appropriate, adaptable, and reliable Multi-Criteria Decision-Making tool on the vertical integration and implementation of urban agriculture in schools, in support of the goals of sustainable development and the circular economy.

Improving the Metabolism and Sustainability of Buildings and Cities Through Integrated Rooftop Greenhouses (i-RTG)

Food security in cities is an increasing concern due to the impact of climate change and the concentration of world population in cities. Urban agriculture (UA) aims at enhancing food production in urban areas, providing potential environmental advantages by reducing food transport, packaging and waste generation. Among UA alternatives, rooftop greenhouses (RTGs) are greenhouses built on top of urban roofs, in which mainly soil-less agriculture systems are used to produce food. When RTGs are integrated into the metabolism of their buildings, they exchange CO2, energy and water to improve their performance. This alternative is called integrated RTG (i-RTG). This chapter analyses the use of i-RTGs to improve buildings and cities’ metabolism and its particular application in the area of Barcelona. This analysis aims to define a new agricultural system from a technological and sustainability approach focusing on Mediterranean cities. Our research is based on the development and results of the Fertilecity project. A particular experimental analysis was conducted at ICTA’s i-RTG lab located near Barcelona. The main factors of interest are architectural and engineering requirements, urban integration, CO2 emissions management, energy consumption, food production, social integration and rainwater harvesting. This analysis has used different methods such as life cycle assessment (LCA), life cycle costing (LCC) and semi-quantitative assessments. Multiple integrated results were obtained both at the building and city scale. For example, we proved that the i-RTG and its flow exchanges with the building could help to save heating energy, waste generation, water consumption and CO2 emissions.