Indoor Environment Quality: Smart Technology in Thermal Comfort, Ventilation, Humidity, Hygiene, Lighting, Acoustics and Water Supply

The 21st century has marked the dawn of an aging population. China’s aging process ranks first worldwide. The country has recognized the gravity of this demographic shift and implemented strategies to address it at the national level. A vast majority of elderly Chinese individuals (approximately 90%) aspire to age in their own homes. Smart homes, endowed with cutting-edge digital technologies, such as AI, the Internet of Things, and big data, hold vast potential for enabling this vision. However, acceptance of smart home products and services among elderly individuals in China remains low. The main reason is that the related products and services fail to effectively alleviate the perceived risk of this population in the R&D process of related products and services, and there is a lack of effective measurement methods. To holistically assess the potential obstacles faced by elderly individuals using smart home products and services, this study targeted individuals aged 45–60 years in China. This study aimed to develop a comprehensive perceived risk scale specific to smart homes for this demographic. Initially, this study identified key risk dimensions and corresponding measurement items through a rigorous literature review, user interviews, and expert consultations. Subsequently, it ensured the reliability and validity of each dimension and its corresponding observation variables through preliminary research, exploratory factor analysis, and confirmatory factor analysis. This approach allowed for a comprehensive understanding of the challenges faced by future elderly individuals when utilizing smart home products and services, thus enabling the development of more effective solutions. The scale encompassed ten factors and seventy measurement items, including Privacy and Security Risk (seven items), Physical Risk (seven items), Technological Risk (nine items), Performance Risk (seven items), Service Risk (nine items), Financial Risk (five items), Psychological Risk (seven items), Industry and Market Risk (six items), Social Support Risk (six items), and Policy and Legal risk (seven items). The measurement scale developed in this study represents a groundbreaking first attempt to create a systematic scale for assessing the perceived risks associated with smart homes for the elderly in China. It not only enables professionals, businesses, and manufacturers to avoid or reduce barriers in the R&D process of related products and services, facilitating smart home industry growth and enhancing user adoption, but also serves as a universal reference for the potential obstacles that digital technology may encounter in addressing aging-related issues, which has significant theoretical value and practical importance. Full article

Recent developments in the field of digital technologies in construction have led to a renewed interest in the use of building information modeling (BIM) for water efficiency analysis (WEA). BIM has emerged as a powerful platform for performance analysis towards sustainable design. However, there is little available in the literature on WEA using BIM. Extensive research has shown that WEA in buildings focuses on rating systems, 3D modeling, clash detection, and rainwater harvesting analysis. This paper presents a digital integrated methodology with in-depth analysis of three domains: (1) analysis of water usage according to plumbing fixtures and inhabitant demand per day, (2) sizing analysis of hydraulic-plumbing systems using the flowrate calculation method, and (3) analysis of alternative systems using harvested rainwater and treated water. The proposed methodology was applied to a multi-family building in Nuevo León, Mexico. The authors conclude that this methodology can easily be implemented in the short term, and that it may provide a significant improvement in WEA. Full article

COVID-19 has caused a considerable proportion of the public to work from home, either part- or full-time, in unregulated domestic conditions, which have not been designed for commercial activities. This study determined what existing lighting conditions were present in a selection of work-from-home (WFH) environments (Objective One) through quantitative lux level and equivalent melanopic lux (EML) readings by evaluating them against regulatory standards, where further study is required to validate the results with a larger dataset. This study also investigated the social demand for human-centric lighting (HCL) installations within WFH environments (Objective Two) through qualitative questionnaires by considering key parameters: sustainability, practicality, and cost. The results of Objective One showed that compliance with general safety lighting requirements was achieved by 80% of the installations. The mean lux level recorded was 452.4 lux and 0.729 uniformity, which fell below commercial requirements defined for commonly performed WFH activities; 34.3% of recorded EML dropped below the regulatory requirements under daylight conditions. When isolated to artificial lighting, only 7.5% of the required EML was achieved. The results of Objective Two showed that generally participants did not feel that their WFH installations were unsuitably lit, however, 46.2% of participants identified noticeable headaches or eye strain when working from home. A total of 80% of participants highlighted that HCL task lighting would be preferable. It was also found that participants were willing to invest in circadian lighting for health, where 63.2% of them would not accept a reduction in efficiency of over 10% compared to non HCL. Wellbeing was found to be participants’ key preference for their lighting systems, followed by efficiency, home impact, and cost. Full article

The luminous environment is an essential factor that affects people’s working and living experiences in buildings. In order to clarify the building luminous environment parameters that are required for occupant satisfaction, we collected 2553 completed questionnaires while conducting field measurements of new and updated luminous comfort metrics in 15 contexts in four cities in China. By developing a five-step approach to identifying the luminous environment needs of different building occupants, including data cleaning, correlation analysis, and nonparametric testing, we determined the thresholds for all key metrics for each scenario. The research results show that different public building environments have unique luminous environment improvement requirements, and this conclusion can guide future lighting design, LED technology and daylighting integration technology. Full article

Indoor landscaping is an environmentally friendly approach that enriches the environment and fosters productivity and comfort for occupants. The practice of incorporating plants into interior spaces requires meticulous care to ensure healthy growth and prolong the benefits of interior greening. This study explores the impact of natural and artificial light, represented by fluorescent lighting on the growth and physiological responses of Codiaeum variegatum and Ardisia japonica. A natural light chamber and an artificial light chamber of identical dimensions were constructed to compare the plants’ physiological responses under consistent temperature, humidity, and illuminance conditions. The results indicate that Codiaeum variegatum and Ardisia japonica exhibited higher chlorophyll content and photosynthetic rates under natural light conditions compared to fluorescent lighting. Furthermore, the study found that natural light offers a rich spectral distribution across various wavelengths, providing an advantage for plant growth. Although direct comparisons between natural and artificial light environments are inherently challenging due to the distinct characteristics of each light source, the study emphasizes the importance of considering the rich spectral distribution of natural light when designing artificial lighting systems for optimal plant growth. In conclusion, understanding the effects of natural and artificial light on indoor plants is crucial to supporting plant growth and creating more effective indoor gardening solutions. Although direct comparisons between natural and artificial light environments are inherently challenging due to the distinct characteristics of each light source, natural light provides a more advantageous environment for growth compared to fluorescent lighting, with Codiaeum variegatum and Ardisia japonica both exhibiting a higher chlorophyll content and photosynthetic rate under natural light conditions. Full article

The indoor environmental quality of a library greatly affects the comfort and productivity of its users while preserving the materials. Despite the high energy consumption of HVACs in libraries, achieving acceptable thermal conditions, acceptable acoustics, and sufficient daylight levels for users remains a challenge. There are limited studies on the IEQ of educational buildings, especially regarding the current situation of libraries. It is important to conduct further studies to define design guidelines promoting indoor environmental conditions. The main objectives of this study were to investigate the IEQ of a campus library to recommend retrofitting strategies. The IEQ parameters in the rare collection room, which houses special collections, and in the library hall were assessed using a full-scale measurement, with eight HOBO data loggers and sensors deployed in various locations to monitor IEQ. A comparison of the results with the standards revealed that rare collection room was unsuitable for maintaining rare collections, as the average indoor air temperature exceeded 21.2 °C, which is beyond the threshold limit. Additionally, the relative humidity ranged from 51.3% to 55.8%, which is marginally high. To provide acceptable indoor conditions, this study recommends retrofitting strategies for the exterior walls, such as using cement plaster with a low thermal conductivity. In the library hall, the reading zone was found to be thermally uncomfortable. The air velocity was below the range of 0.15 ms⁻¹ to 0.50 ms⁻¹ recommended by MS 1525. The average CO₂ level was 479.5 ppm, with some points registering an increase of up to 588 ppm. The noise level in the library hall ranged between 43 dB(A) and 61 dB(A), while the light intensity was below 300 lux in the reading area, which is not within the acceptable range. This study suggests improvement solutions, such as implementing an air temperature between 24.5 and 26.5 °C for higher thermal comfort and increasing the window-to-wall ratio to utilize natural daylight. These findings provide insights into the design of new libraries and the renovation of existing ones, ensuring that libraries continue to serve as vibrant centers of knowledge and learning for generations to come. Full article

Human performance and health are among the most relevant topics in modern society, especially at young ages, when academic performance is indispensable. Thus, as humans spend most of their life inside a building, thermal comfort and indoor air quality are essential aspects of a room. The aim of the current study is to numerically evaluate the main thermal comfort parameters such as PMV and PPD as well as indoor air quality, i.e., CO₂ concentration, in library group study rooms at the University of Gävle in Sweden. Rotroninc Measurement Solutions CL11 sensors were utilized for temperature measurements. Simulation models were created and validated based on building data as well as temperature measurements. Several simulations were conducted throughout the year, covering different periods. The results show that even though the ventilation system, with only temperature control, works as intended for maintaining thermal comfort, the CO₂ concentration rises above 1000 ppm when more than one student occupies the rooms, which is not recommended by different thermal comfort ruling institutions. Consequently, a modification to the ventilation system control is recommended, changing it from temperature control to CO₂ and temperature control. Full article

People spend about 90% of their time in closed spaces such as residential and office environments, and indoor environmental quality (IEQ) has effects on their health, well-being, overall comfort and work productivity. The IEQ domains (i.e., thermal, acoustic, visual and indoor air quality) are able to influence office users’ work day and even cause the onset of diseases. This review aims at investigating IEQ in offices and the multidomain combined effects on occupants’ overall comfort. Studies published between 2016 and 2022 were summarized, focusing on four research questions formulated to deepen the knowledge on (i) IEQ perception and evaluation, (ii) IEQ indexes and parameters, (iii) factors that influence comfort perception and (iv) IEQ and comfort representation in space and time. For these research questions, a total of 29, 19, 10 and 9 studies, found on the Scopus database through a keywords search, were considered, respectively. The studies were included only if they appraised a multidomain approach. The results obtained for each research question reveal that: (i) Post-Occupancy Evaluation (POE) surveys are often applied to understand how occupants perceive IEQ, and in-field monitoring based on low-cost sensors is implemented more and more to acquire IEQ data, (ii) a set of indexes and parameters for IEQ assessment is not standardized yet, although some parameters are commonly used, (iii) personal factors like age and gender, and contextual factors like workstation location and office type, influence occupants’ comfort perception and (iv) dashboards are used to allow office end-users to visualize the indoor conditions of the environment. Full article