Purpose: Taking into account the current relevance of the concept of smart city connected with the Internet of Things, this work aims to study the implementation of this concept by applying a new energy model in an existing public building. The purpose of this paper is to enhance the sustainability and energy autonomy of the building. Design/methodology/approach: The building referred to in the case study is a library, and simulations related to the ongoing study are based on an energy audit, comprising a survey on electrical and thermal energy consumption. The innovative proposed model consists of a mix of energy production processes based on photovoltaic panels and biomass boilers. Economic analysis of the energy model has already yielded some results regarding the payback on investment, as well as avoided emissions in the context of development of a low-carbon economy with avoided emissions and socioeconomic advantages. Findings: It is possible to enhance the sustainability of the library studied by the retrofit of the current energy system. With the integration of photovoltaic panels and the conversion or replacement of boilers from natural gas to biomass, the GHG emissions could drop around 121 t CO₂ per year. Another benefit would be the inclusion of endogenous resources over imported energy resources. The payback period for the measures proposed ranges from 2.5 to 8 years, proving that the increase in environmental sustainability is viable. Originality/value: The intention here is to implement the concept of smart city, in more sustainable buildings, bringing them to the lowest possible energy consumption levels, hence increasing performance and comfort. Also, taking into account that the energy-consuming buildings are already constructed, it is urgent to reconvert them to lower the use of energy and emissions using technologies based on renewable energy, boosting the use of local resources.

This paper presents a tool for automating the design of road tunnels lighting systems. The tunnel lighting system must guarantee some minimal luminance values in order to ensure a easy driving and visual perception. The lights distribution, in different tunnel zones, is obtained in the proposed technique by using a genetic algorithm. The developed software framework automatically selects the best light type and its localization, according to a specified design objective, along the tunnel independently of the light manufacturer.

The way of energy use in the European Union (EU) needs to be improved by continuous promotion of sustainability and an efficient manner to ensure citizens' quality of life. This work presents two new energy models: i) retrofit of the present energy system in a public library building; ii) improving energy efficiency in public lighting using new technological solution Light Emission Diode (LED), new methods of control and management while leveraging the use of renewable energy as power supply. Both can act as a vehicle to disseminate concepts of Smart City (SC) and Internet of Things (IoT), also, as the development of energy production based on renewable energies: biomass and sunlight. With these two proposals it is intended to improve energy efficiency behaviours reducing energy waste, making use of the latest techniques and equipment, which promote more efficient management. This will lead to an effective reduction of energy consumption associated with public lighting while maintaining recommended levels of luminance in different situations. Finally this research is also to complete, a long-term goal of the EU, which is to develop a society that better uses their energy systems and, in Portugal, increase the use of available renewable energy sources.

The efficiency of wastewater treatment systems must be reflected in the removal of the pollutant load from the influent and the optimal energy performance of electrical equipment. Wastewater Treatment Plants (WWTPs) are part of the Intensive Energy Consumption Management System (SGCIE) and are therefore subject to mandatory energy audits. This article aims to assess the impact of an energy audit in a WWTP, according to ISO 50001:2018 and the Plan-Do-Check-Act (PDCA) methodology, to identify and quantify both persistent and transient energy inefficiencies. According to the results, the energy audit contributed to an approximate 10.8% reduction in electrical energy consumption. During the assessment, several challenges were identified that may compromise the effectiveness of audits in improving energy performance. The complexity of the treatment model, aging infrastructure and equipment, the lack of real-time data, and a limited number of indicators hinder the proper management of inefficiency phenomena, particularly transient ones.