The Role of HVAC Design and Windows on the Indoor Airflow Pattern and ACH

The purpose of heating, ventilation, and air conditioning (HVAC) systems are to create optimum thermal comfort and appropriate indoor air quality (IAQ) for occupants. Air ventilation systems can significantly affect the health risk in indoor environments, especially those by contaminated aerosols. Therefore, the main goal of the study is to analyze the indoor airflow patterns in the heating, ventilation, and air conditioning (HVAC) systems and the impact of outlets/windows. The other goal of this study is to simulate the trajectory of the aerosols from a human sneeze, investigate the impact of opening windows on the number of air changes per hour (ACH) and exhibit the role of dead zones with poor ventilation. The final goal is to show the application of computational fluid dynamics (CFD) simulation in improving the HVAC design, such as outlet locations or airflow rate, in addition to the placement of occupants. In this regard, an extensive literature review has been combined with the CFD method to analyze the indoor airflow patterns, ACH, and the role of windows. The airflow pattern analysis shows the critical impact of inflow/outflow and windows. The results show that the CFD model simulation could exhibit optimal placement and safer locations for the occupants to decrease the health risk. The results of the discrete phase simulation determined that the actual ACH could be different from the theoretical ACH as the short circuit and dead zones affect the ACH.

Download Full-text

OP71 Understanding Hospitals’ Performance Variability: Conceptual Framework

International Journal of Technology Assessment in Health Care ◽

10.1017/s0266462319001296 ◽

2019 ◽

Vol 35 (S1) ◽

pp. 17-18

Author(s):

Americo Cicchetti ◽

Marco Marchetti ◽

Irene Gabutti ◽

Stefania Boccia ◽

Maria Lucia Specchia ◽

...

Keyword(s):

Contextual Factors ◽

Deep Understanding ◽

Organizational Factors ◽

Hospital Performance ◽

Healthcare Sector ◽

Extensive Literature ◽

Managerial Accounting ◽

Health Technologies ◽

The Impact

IntroductionUnderstanding of the role of contextual factors in determining the real value of health technologies is one of the major challenges for the use of Health Technology Assessment (HTA) methodology within hospitals. Moreover, the responsibility of assessing hospital performance is problematic. Although a number of managerial tools are available to appraise outcomes, there is little evidence on the role of contextual variables and how they might contribute to hospital performance.MethodsBased on three extensive literature reviews, a pragmatic framework has been developed to understand interactions between organizational factors and health technologies on hospitals’ performance. Three main causal relationships emerge: (i) direct relationship between contextual factors and performance; (ii) an effect of contextual factors on the capability of technologies to “produce value”; (iii) an influence of organizational factors on clinical evidence-based decision-making. This pragmatic framework was designed within the IMPACT HTA EU Horizon 2020 Research Project.ResultsThe contextual dimensions are ascribable to five domains: organizational structure; managerial accounting tools; information, communication and technology (ICT) tools; human resource management (HRM) tools; hospital-based HTA procedures. The impact of contextual factors on technologies’ ability to produce value is highly overlooked in literature. Some effort in this sense exists only in the analysis of health information technologies. Moreover, among the contextual dimensions, only HRM tools have inspired a lively debate. The definition of hospital performance is amenable to multiple domains: accessibility, appropriateness, efficiency, safety and patient centeredness (continuity of care).ConclusionsAlthough hospital performance is a pivotal topic in the healthcare sector, a deep understanding of how contextual factors may affect it is missing. The theoretical framework developed provides a tool to understand the multiple dimensions able to affect hospital performance. On one hand contextual dimensions may provide a direct effect on hospital performance. On the other, they may affect the extent to which technologies are capable of producing value.

Download Full-text

Identification of SARS-CoV-2 RNA in Healthcare Heating, Ventilation, and Air Conditioning Units

10.1101/2020.06.26.20141085 ◽

2020 ◽

Cited By ~ 1

Author(s):

Patrick F. Horve ◽

Leslie Dietz ◽

Mark Fretz ◽

David A. Constant ◽

Andrew Wilkes ◽

...

Keyword(s):

Air Conditioning ◽

High Efficiency ◽

Healthcare Setting ◽

Hvac Systems ◽

Mitigation Strategies ◽

Healthcare Settings ◽

Viral Particles ◽

Air Handling Units ◽

Available Information

AbstractAvailable information on Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) transmission by small particle aerosols continues to evolve rapidly. To assess the potential role of heating, ventilation, and air conditioning (HVAC) systems in airborne viral transmission, this study sought to determine the viral presence, if any, on air handling units in a healthcare setting where Coronavirus Disease 2019 (COVID-19) patients were being treated. The presence of SARS-CoV-2 RNA was detected in approximately 25% of samples taken from nine different locations in multiple air handlers. While samples were not evaluated for viral infectivity, the presence of viral RNA in air handlers raises the possibility that viral particles can enter and travel within the air handling system of a hospital, from room return air through high efficiency MERV-15 filters and into supply air ducts. Although no known transmission events were determined to be associated with these specimens, the findings suggest the potential for HVAC systems to facilitate transmission by environmental contamination via shared air volumes with locations remote from areas where infected persons reside. More work is needed to further evaluate the risk of SARS-CoV-2 transmission via HVAC systems and to verify effectiveness of building operations mitigation strategies for the protection of building occupants. These results are important within and outside of healthcare settings and may present a matter of some urgency for building operators of facilities that are not equipped with high-efficiency filtration.

Download Full-text

Effect of Drought and Salt Stress on Cereal Crop Plants and their Proteomic and Physiological Studies

Journal of Biotechnology and Biomedical Science ◽

10.14302/issn.2576-6694.jbbs-20-3525 ◽

2020 ◽

Vol 2 (3) ◽

pp. 43-59

Author(s):

Kaligotla Venkata Subrahmanya Anirudh ◽

Tanushree Chakraborty ◽

Rajesh K. Srivastava ◽

Nasim Akhtar

Keyword(s):

Salt Stress ◽

Genomic Sequence ◽

Direct Consequence ◽

Cereal Crops ◽

Extensive Literature ◽

Drought And Salt Stress ◽

Photosynthetic Potential ◽

Root Tissues ◽

The Impact

The photosynthetic potential and underlying internal metabolism of a plant are some of the most commonly affected physiological functions as a direct consequence of stresses due to salt and water resulting in hindering plant growth and productivity. Under the influence of such detrimental stresses, a drastic alteration in a plant's osmotic requirements, hormonal production, shedding of leaves, and closure of stomata, along with a lessening in the diffusion and transportation of CO2 and H2O are commonly seen. This review unfolds with a description of the basic methodology involved in the proteomic analysis of various proteins involved in stress response along with a brief idea on identifying and obtaining a genomic sequence for proteomic studies. It then dives deep into understanding the impact of abiotic stresses such as salinity, drought and high temperatures on cereal crops such as rice and sorghum as well as the internal dynamics of tolerance mechanism unfolding during stresses have also been described. Extensive literature describing the proteomic and physiological responses to primary and secondary effects of salt stress in cereal crops emphasizing on ROS production and apoptosis, the role of osmolytes as ROS scavengers during osmotic stress and vacuolar antiporters in ionic stress along with the responses during drought stress such as the accumulation of LEA proteins and ABA-based signaling has been reviewed and critically discussed. The study also sheds light on some experimental proteomic studies conducted on the seedlings, root tissues, and shoots of rice cultivars.

Download Full-text

The Role of Air Conditioning in the Diffusion of Sars-CoV-2 in Indoor Environments: a First Computational Fluid Dynamic Model, based on Investigations performed at the Vatican State Childrens Hospital.

10.1101/2020.08.25.20181420 ◽

2020 ◽

Author(s):

Luca Borro ◽

Lorenzo Mazzei ◽

Massimiliano Raponi ◽

Prisco Piscitelli ◽

Alessandro Miani ◽

...

Keyword(s):

Air Conditioning ◽

Indoor Environment ◽

Hvac Systems ◽

Indoor Environments ◽

Hospital Room ◽

Childrens Hospital ◽

Infection Index ◽

Indoor Scenarios ◽

Ventilation Systems

Background: About 15 million people worldwide were affected by the Sars-Cov-2 infection, which already caused 600,000 deaths. This virus is mainly transmitted through exhalations from the airways of infected persons, so that Heating, Ventilation and Air Conditioning (HVAC) systems might play a role in spreading the infection in indoor environments. Methods: We modelled the role of HVAC systems in the diffusion of the contagion through a Computational Fluid Dynamics (CFD) simulations of cough at the Vatican State childrens hospital Bambino Gesu. Both waiting rooms and hospital rooms were modeled as indoor scenarios. A specific Infection-Index parameter was used to estimate the amount of contaminated air inhaled by each person present in the simulated indoor scenarios. The potential role of exhaust air ventilation systems placed above the coughing patients mouth was also assessed. Results: Our CFD-based simulations show that HVAC air-flow remarkably enhance infected droplets diffusion in the whole indoor environment within 25 seconds from the cough event, despite the observed dilution of saliva particles containing the virus. In the waiting room simulation, Infection-Index parameter increases the faster the higher the HVAC airflow. Greater flows of air conditioning correspond to greater diffusion of the infected droplets. The proper use of Local Exhaust Ventilation systems (LEV) simulated in the hospital room was associated to a complete reduction of infected droplets spreading from the patient s mouth in the first 0.5 seconds following the cough event. In the hospital room, the use of LEV system completely reduced the index computed for the patient hospitalized at the bed next to the spreader, with a decreased possibility of contagion. Conclusions: CFD-based simulations for indoor environment can be useful to optimize air conditioning flow and to predict the contagion risk both in hospitals/ambulatories and in other public/private settings.

Download Full-text

How communication departments contribute to corporate success

Journal of Communication Management ◽

10.1108/jcom-12-2017-0146 ◽

2018 ◽

Vol 22 (4) ◽

pp. 397-415 ◽

Cited By ~ 10

Author(s):

Ansgar Zerfass ◽

Sophia Charlotte Volk

Keyword(s):

Critical Role ◽

Extensive Literature ◽

Organizational Strategies ◽

Communication Management ◽

Content Type ◽

Qualitative Case Studies ◽

Big Picture ◽

The Impact ◽

Depth Interviews

PurposeThe purpose of this paper is to clarify and demonstrate the core contributions of communication departments to organizational success beyond traditional ideas of messaging or information distribution. The main aim is to develop a better understanding of the different facets of value that the communication function delivers by introducing a distinction between strategic and operational contributions, following established management models.Design/methodology/approachThe research is based on an extensive literature review at the nexus of communication management and strategic management research and ten qualitative case studies in large, internationally operating German organizations from different industries, combining in-depth interviews and document analyses.FindingsThe newly developed Communications Contributions Framework demonstrates that communications serve the corporation in four strategic and operational dimensions and emphasizes the critical role of communications in reflecting and adjusting organizational strategies, i.e. through identifying opportunities to innovate or securing intangible assets.Practical implicationsThe paper outlines different application scenarios for how the new framework can be used in practice, i.e. as a multi-faceted rationale for explaining the impact of communication departments in the language of top management and reporting communication success in the logic of business.Originality/valueThe framework provides the first theoretically and empirically based “big picture” of communications’ contributions to corporate success, designed to lay ground for further discussions both in academia and in practice.

Download Full-text

Land Grabbing and Jatropha in India: An Analysis of ‘Hyped’ Discourse on The Subject

Land ◽

10.3390/land10101063 ◽

2021 ◽

Vol 10 (10) ◽

pp. 1063

Author(s):

Anika Trebbin

Keyword(s):

Small And Medium Enterprises ◽

Extensive Literature ◽

Land Grabbing ◽

Land Grab ◽

Qualitative Survey ◽

Global Land ◽

The Subject ◽

Medium Enterprises ◽

The Impact

In the early 2000s, powerful narratives (re-)emerged around the food–fuel–land nexus, which, combined with the financial, food, and fuel crises of 2007-08, sparked new concerns about the finiteness of our resources and triggered, as well as partially justified, the then following land rush. Around the same time, a hyped debate also developed around biofuels as a potential fix to some of the global scarcity problems in which jatropha held a particularly prominent position as a new miracle crop. This study examines the concurrence of jatropha and the land grabbing hype in India, the leading promotor of the plant globally, and asks what effect the global land grab discourse had on actual jatropha investments in the country. To do so, an extensive literature review, discourse analysis, and qualitative survey were conducted, with a specific focus on jatropha investors. The study found that both hyped discourses have impacted investor decisions, but the impact varied depending on the types of company. This study adds a yet underrepresented investor perspective to the global land grabbing discourse and highlights a need to also consider the role of small and medium enterprises in land grabbing processes.

Download Full-text

Microbiological Aspects of Energy-Efficient HVAC (Ventilation) Systems Houses

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.1041.354 ◽

2014 ◽

Vol 1041 ◽

pp. 354-357

Author(s):

Jiří Bernard ◽

Lukáš Frič ◽

Olga Rubinová ◽

Marcela Počinková ◽

Aleš Rubina ◽

...

Keyword(s):

Energy Efficient ◽

Air Conditioning ◽

Heat Recovery ◽

Hvac Systems ◽

Internal Environment ◽

Real Objects ◽

Air Conditioning Systems ◽

The Impact ◽

Microbiological Aspects ◽

Ventilation Systems

Currently it is under pressure to reduce the energy consumption of the buildings. The pressure is noticeably reflected in the current way of building designing, in general. Therefore, essential part of these objects become air-conditioning (ventilation) systems, mainly due to possibilities of heat recovery and controlled ventilation. This contribution focuses on ventilation systems, low energy houses, which aims to highlight the issue of purity of these systems on the microbial level. Evaluate the impact of external and internal environment following the condition of HVAC systems in time, in the real objects. The purpose (aim) of this all is to remind that there are other aspects that have to be considered in the design and subsequently, in the use of the systems, such as the impact of the nature of the building use on the purity of air-conditioning systems. It is necessary to point out that the presented ventilation systems have a significant impact on the creation of the internal environment, and equally they can harm, instead to be beneficial.

Download Full-text

The impact of heating, ventilation, and air conditioning design features on the transmission of viruses, including the 2019 novel coronavirus: a systematic review of filtration

10.1101/2021.09.23.21264025 ◽

2021 ◽

Author(s):

Brian A Fleck ◽

Gail M. Thornton ◽

Lexuan Zhong ◽

Lisa A Hartling ◽

Dhyey Dandnayak ◽

...

Keyword(s):

Systematic Review ◽

Air Conditioning ◽

Virus Transmission ◽

Infection Risk ◽

Hvac Systems ◽

Airborne Transmission ◽

Virus Removal ◽

Filter Efficiency ◽

Novel Coronavirus ◽

The Impact

Historically, viruses have demonstrated airborne transmission. Emerging evidence suggests the novel coronavirus (SARS-CoV-2) that causes COVID-19 may also spread by airborne transmission. This is more likely in indoor environments, particularly with poor ventilation. In the context of potential airborne transmission, a vital mitigation strategy for the built environment is heating, ventilation, and air conditioning (HVAC) systems. HVAC features could modify virus transmission potential. A systematic review following international standards was conducted to comprehensively identify and synthesize research examining the effectiveness of filters within HVAC systems in reducing virus transmission. Twenty-three relevant studies showed that: filtration was associated with decreased transmission; filters removed viruses from the air; increasing filter efficiency (efficiency of particle removal) was associated with decreased transmission, decreased infection risk, and increased viral filtration efficiency (efficiency of virus removal); increasing filter efficiency above MERV 13 was associated with limited benefit in further reduction of virus concentration and infection risk; and filters with the same efficiency rating from different companies showed variable performance. Increasing filter efficiency may mitigate virus transmission; however, improvement may be limited above MERV 13. Adapting HVAC systems to mitigate virus transmission requires a multi-factorial approach and filtration is one factor offering demonstrated potential for decreased transmission.

Download Full-text

Detailed Comparison of the Operational Characteristics of Energy-Conserving HVAC Systems during the Cooling Season

Energies ◽

10.3390/en12214160 ◽

2019 ◽

Vol 12 (21) ◽

pp. 4160 ◽

Cited By ~ 2

Author(s):

Chul-Ho Kim ◽

Seung-Eon Lee ◽

Kwang-Ho Lee ◽

Kang-Soo Kim

Keyword(s):

Air Conditioning ◽

Detailed Comparison ◽

Energy Performance ◽

Hvac Systems ◽

Base Case ◽

Airflow Rate ◽

Outdoor Air ◽

Air Volume ◽

Operational Characteristics ◽

Energy Conserving

To provide useful information concerning energy-conserving heating, ventilation, and air-conditioning (HVAC) systems, this study used EnergyPlus to analyze in detail their operational characteristics and energy performance. This study also aimed to understand the features of the systems under consideration by investigating the dry-bulb temperature, relative humidity, and airflow rate at major nodes in each system’s schematic. Furthermore, we analyzed the indoor environment created by each HVAC system, as well as examining the cooling energy consumptions and CO2 emissions. The HVAC systems selected for this study are the variable air volume (VAV) commonly used in office buildings (base-case model), constant air volume (CAV), under-floor air distribution (UFAD), and active chilled beam (ACB) with dedicated outdoor air system (DOAS). For the same indoor set-point temperature, the CAV’s supply airflow was the highest, and VAV and UFAD were operated by varying the airflow rate according to the change of the space thermal load. ACB with DOAS was analyzed as being able to perform air conditioning only with the supply airflow constantly fixed at a minimum outdoor air volume. The primary cooling energy was increased by about 23.3% by applying CAV, compared to VAV. When using the UFAD and ACB with DOAS, cooling energy was reduced by 11.3% and 23.1% compared with VAV, respectively.

Download Full-text

COVID-19 Pandemic and Tourism: The Impact of Health Risk Perception and Intolerance of Uncertainty on Travel Intentions

10.20944/preprints202010.0432.v1 ◽

2020 ◽

Author(s):

Anastasiya Golets ◽

Jéssica Farias ◽

Ronaldo Pilati ◽

Helena Costa

Keyword(s):

Risk Perception ◽

Health Risk ◽

Online Survey ◽

Intolerance Of Uncertainty ◽

Risk And Uncertainty ◽

Tourist Behaviour ◽

The Impact ◽

Health Risk Perception ◽

Perceived Probability

Understanding tourist behaviour during and after major tourism crises is essential to help destinations recover. The COVID-19 pandemic, a period of uncertainty and risk, makes it relevant to assess factors that influence travel intentions. There has been little research on tourist behaviour during health crises and, in particular, on perceived health risk and uncertainty effects on travel intentions. This study was carried out during the first months of the pandemic in Brazil and aims to investigate the role of health risk perception and intolerance of uncertainty on travel intentions for 2020 and 2021. We applied an online survey to 1,150 Brazilian participants from March to May of 2020. Our findings indicate that perceived COVID-19 severity, perceived probability of contracting it, and expected pandemic duration are significant predictors of travel intentions for both years. This paper sheds new light on tourist behaviour in the context of global health crises.

Download Full-text