Internet of Things (IoT) has been developing to become a free exchange of useful information between multiple real-world devices. Already spread all over the world in the most varied forms and applications, IoT devices need to overcome a series of challenges to respond to the new requirements and demands. The main focus of this manuscript is to establish good practices for the design of IoT devices (i.e., smart devices) with a focus on two main design challenges: power and connectivity. It groups IoT devices in passive, semi-passive, and active, giving details on multiple research topics. Backscatter communication, Wireless Power Transfer (WPT), Energy Harvesting (EH), chipless devices, Simultaneous Wireless Information and Power Transfer (SWIPT), and Wake-Up Radio (WUR) are some examples of the technologies that will be explored in this work.
A high-occupancy elementary school building recently retrofitted, with low energy consumption and no central climatization systems for heating, cooling and ventilation, located in the North region of Portugal was widely monitored to assess radon risk as a measure of indoor air quality. The experimental campaign was implemented in the spring of 2018 and during a period of one month, the radon gas concentration was continuously assessed. The main goal of the study is to evaluate the influence of variables such as the occupancy, the location of the monitored rooms and ventilation actions that were undertaken, to effectively evaluate the risk to radon exposure in a scenario of very low energy spent for heating, cooling and ventilation. The final results showed that 46% of the rooms exceeded the limit of 300 Bq.m⁻³ imposed by the Portuguese legislation in force. However, when considering a dosimetric approach reflecting the school building occupation profile (SBOP), by the calculation of the Indoor Annual Effective Dose (IAED), 93% of the rooms were above the occupational dose limit of 1 mSv/year, recommended by the International Commission on Radiological Protection (ICRP). Based on the results, there is evidence that the risk associated to the exposure to radon gas in indoor environments does not depend only on its concentration in the monitored room, but also on the number of occupants, period of occupancy, ventilation rate and on the location of the room in the building.
Radon gas is considered by the World Health Organization (WHO) as one of the most relevant indoor pollutants with proven relationship with higher lung cancer risk. Hence, indoor radon exposure in badly ventilated and extensively occupied rooms increases drastically the risk of health problems. Due to the geological nature of local soil, the Northwest region of Portugal is critical concerning indoor radon exposure. The new legislation is already in force to combat the problem by adopting a remediation strategy in order to reduce the occupants ́ risk in local buildings. However, a remediation strategy involves not only manual or automatic mitigation actions to reduce indoor radon concentration, but also awareness-raising campaigns developed amongst buildings ́ occupants and local community making part of an action plan to deal with the problem. In this paper we present a new case study of 15 public buildings assessed in 2018 through short-term measurements to characterize indoor radon gas concentration, in an inner city in the Northwest region of Portugal. Radon risk was assessed to evaluate occupants’ risk exposure and to define an Action Plan concerning radon gas remediation.
Radon is a naturally occurring radioactive gas that can easily accumulate in indoor environments, being classified by the World Health Organization (WHO) as the second most important cause of lung cancer after tobacco, negatively impacting public health. The presence of this gas indoors tends to increase in regions were the subsoil presents a higher granitic prevalence, such as the northern and central interior regions of Portugal. The paper introduces RnMonitor, a Cyber-Physical System (CPS) with humans-in-the-loop specifically designed for online monitoring and active mitigation of radon risk in public buildings. The system takes advantage of an IoT device specifically designed to acquire radon concentration and other relevant Indoor Air Quality (IAQ) and consequently transmit the collected data, using a low-power wide-area network (LPWAN), to a cloud-engine for reasoning and therefore trigger specific mitigation actions, e.g. manual ventilation.
Depending on the architectural typology and function of a specific building or compartment, Building Occupancy Estimation (BOE) is a critical factor for effective green building management. By estimating the building occupancy over time we can reduce the overall energy consumption, and therefore, improve the building energy efficiency. In a public building context, for example, such as an administration office, a school or a kindergarten, building occupancy is normally restricted to a regular work schedule and its effective occupation can considerably vary in this period, in terms of number of occupants per compartment or in the overall building, and therefore considerable impact the building energy consumption for heating, HVAC, lightning, etc. This paper presents the design and implementation of a cost-effective IoT edge device for BOE. The proposed device collects and transmits up to the cloud, several networking and indoor environmental parameters, that combined, will be later used to specify a multi-parameter metric for effective BOE.
IoT-based monitoring (i.e. smart monitoring) technologies have been recently used for on-line monitoring in many application fields, such as home, environmental and industrial process monitoring. People spend at least half of their life inside buildings, therefore, Indoor Air Quality (IAQ) plays an important role both on human health and on buildings’ sustainability. Radon gas is one of the most important parameters regarding IAQ assessment, being considered by the World Health Organization (WHO) as the second-largest risk factor associated with lung cancer. This paper aims to present RnMonitor, a WebGIS- based platform developed for effective Radon Risk Management and expedite in situ deployment of IoT-based sensors. Given the fact that the spatial context is key for visual and data analytics, the proposed platform takes advantage of a hierarchy of spatially related entities (buildings/rooms/devices) that are natively georeferenced in the system, and thus providing spatial context to acquired data, and other relevant metrics, by means of a simple, responsive and intuitive web-based application.
The aim of this paper is to analyze the radon concentration in 3 granitic single-family houses, located in the countryside region, Barcelos, North of Portugal, one of the highest indoor radon concentrations regions, due to the granitic nature of the soil. In situ measurements were taken using digital radon monitors. Simultaneously, thermo-hygrometric measurements were undertaken to allow a more detailed assessment of the relation between the measured variables. Measurements were performed during the summer and autumn season of 2016. The results attained have shown that the human occupancy, mostly through passive ventilation processes, works as a radon concentration mitigation factor.
An ancient monastery placed in Ponte de Lima, an inner village in Alto Minho region, North of Portugal, was monitored in order to assess radon gas concentrations. The aim of this paper is to perform a short-term radon gas characterization to assess the radon risk in a school building and therefore propose adequate mitigation strategies. The experimental campaign took place during spring and summer of 2017 and was carried out in 2 complementary steps involving 17 different sites. This study revealed that the radon concentration levels are above the legal limit of 400 Bq.m-3, in 77% of the samples. The value rises to 86% when Euratom Directive limit of 300 Bq.m-3 is considered. Furthermore, the results obtained that indoor radon concentration varies with the occupancy of the rooms, since it is evident that the human ventilation actions have a considerable impact on the reduction of its concentration.
The use of smart devices in buildings is many times compromised by its form and size. Smart devices are composed of several components including sensors, boards, batteries, processing units, and antennas. However, the form and size of the smart devices are usually limited due to antenna restrictions. In this paper, we propose the architecture of a compact low-cost LoRa smart device designed for easy deployment in smart building applications. The proposed device architecture features a reduced size embedded antenna and an ultra-low-power microcontroller to interface several sensors and actuators. The results obtained have shown that the proposed design can be used for communication, between two compact LoRa devices, in line-of-sight for up to 4.2 km, in urban environments for up to 1.2 km and also for in-building communications for up to 152 m, without compromising the low-power features that LoRa supports.
This paper presents the design methodology used to specify a Human-in-the-Loop Cyber-Physical System (HITL-CPS) for online monitoring and active mitigation of the indoor radon gas concentration in non-residential granitic buildings with regular human occupation restricted to a work schedule, such as public buildings like administration offices, schools, kindergartens, etc. The paper follows the methodology that is being carried out in the RnMonitor R&D project in order to design the overall CPS architecture specification using the following approach: i) Conceptual Approach and Application Requirements; ii) Design Specifications and iii) Architecture Definition. At the end, main conclusions are presented alongside with a set of promising avenues for future development.