Life cycle assessment is applied to assess the environmental benefits and trade-offs of a solar-assisted heating, ventilating, and air-conditioning (HVAC) system installed in the CIESOL building in Almeria (southeastern Spain). The environmental performance of this system is compared to that of a conventional HVAC system using a heat pump. The study evaluates these systems from cradle to grave, and the impact assessment includes, in addition to the CML2001 method, an impact category dealing with impacts on freshwater resources. The results show that the solar-assisted HVAC involves lower impacts in many impact categories, achieving, as an example, a reduction of 80% in greenhouse-gas emissions. On the other hand, key weak points of this system are the production of capital goods, but specially water use for cooling, due to its high impact on freshwater resources. Minimization of water requirements should be a priority for further development of this promising technology.
Download full-text PDF |
Source |
---|---|
http://dx.doi.org/10.1021/es9027088 | DOI Listing |
ACS EST Air
January 2025
Lyles School of Civil & Construction Engineering, Purdue University, West Lafayette, Indiana 47907, United States.
Commercial HVAC systems intended to mitigate indoor air pollution are operated based on standards that exclude aerosols with smaller diameters, such as ultrafine particles (UFPs, D ≤ 100 nm), which dominate a large proportion of indoor and outdoor number-based particle size distributions. UFPs generated from occupant activities or infiltrating from the outdoors can be recirculated and accumulate indoors when they are not successfully filtered by an air handling unit. Monitoring UFPs in real occupied environments is vital to understanding these source and mitigation dynamics, but capturing their rapid transience across multiple locations can be challenging due to high-cost instrumentation.
View Article and Find Full Text PDFJ Expo Sci Environ Epidemiol
January 2025
Department of Environmental and Occupational Health, Joe C. Wen School of Population & Public Health, University of California, Irvine, CA, USA.
Background: Children living in communities with lower socioeconomic status and higher minority populations are often disproportionately exposed to particulate matter (PM) compared to children living in other communities.
Objective: We assessed whether adding HEPA filter air cleaners to classrooms with existing HVAC systems reduces indoor air pollution exposure.
Methods: From July 2022 to June 2023, using a block randomized crossover trial of 17 Los Angeles Unified School District elementary schools, classroom PM concentrations were monitored and compared for 99 classrooms with HEPA filter air cleaners and 87 classrooms with non-HEPA filter air cleaners.
Sci Rep
January 2025
Department of Electrical Engineering, Faculty of Engineering at Shoubra, Benha University, Cairo, 11629, Egypt.
High voltage alternating current (HVAC) and high voltage direct current (HVDC) transmission systems have acted as the pillars for the transmission field in power networks. Thus, two types of circuit breakers (CBs) existed; HVDC-CB and HVAC-CB. This imposed a burden on manufacturers by requiring them to set up a separate production line for each type of them, increasing production time and overall cost.
View Article and Find Full Text PDFPrisons have been hotspots for COVID-19 and likely an important driver of racial disparity in disease burden. From the first COVID-19 case detected through March 25, 2022, 66,684 of 196,652 residents of California's state prison system were infected, most of them in two large winter waves of outbreaks that reached all 35 of the state prisons. We used individual-level data on disease timing and nightly room assignments in these prisons to reconstruct locations and pathways of transmission statistically, and from that estimated reproduction numbers, locations of unobserved infection events, and the subsequent magnitude and distribution of long COVID prevalence.
View Article and Find Full Text PDFData Brief
December 2024
Department of Computer Engineering, Mashhad Branch, Islamic Azad University, Mashhad, Iran.
With the development of smart buildings, the risks of cyber-attacks against them have also increased. One of the popular and evolving protocols used for communication between devices in smart buildings, especially HVAC systems, is the BACnet protocol. Machine learning algorithms and neural networks require datasets of normal traffic and real attacks to develop intrusion detection (IDS) and prevention (IPS) systems that can detect anomalies and prevent attacks.
View Article and Find Full Text PDFEnter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!