scholarly journals Optimization of Controlled Mechanical Ventilation Systems for Indoor Acoustic Comfort

Designs ◽  
2021 ◽  
Vol 5 (3) ◽  
pp. 48
Author(s):  
Nicola Granzotto
Keyword(s):  
Mechanical Ventilation ◽  
Ventilation System ◽  
Energy Performance ◽  
Class I ◽  
Winter Period ◽  
Living Room ◽  
Fundamental Factor ◽  
Acoustic Comfort ◽  
Controlled Mechanical Ventilation ◽  
Fan Speed

The indoor air quality inside living spaces is a fundamental factor in providing adequate comfort. In order to do this, a minimum air exchange must be ensured. This can be obtained by means of natural or mechanical ventilation or using the Controlled Mechanical Ventilation system (CMV). CMV ensures better energy performance, as in the winter period, the warm air that comes out of the building preheats the cold air that enters, and the opposite occurs in the summer period. A possible problem with CMV is the noise of the fans due to the movement of air and to the electric motor rotation. This work presents the results of acoustic measurements performed on an apartment equipped with CMV, operating in a single and simultaneous mode. Acoustic simulations are also presented using raytracing software on three typical apartments. The acoustic simulation carried out using an adequately calibrated 3D model has proved to be a valid support for the study of noise in rooms connected by doors and corridors. By differentiating the fan speed of the CMV, a considerable acoustic comfort improvement was obtained in the bedrooms and in the living room/kitchen. Class I for living rooms and class I or II for bedrooms according to the EN 16798-1 standard were achieved through speed optimization.

An analytical study to evaluate the impact of distributed zone fans on the air flow rate in a mechanical ventilation system

2019 ◽  
Vol 41 (4) ◽  
pp. 507-516
Author(s):  
Fa-Li Ju ◽  
Liying Liu ◽  
Xiaoping Yu
Keyword(s):  
Mechanical Ventilation ◽  
Flow Rate ◽  
Pressure Ratio ◽  
Air Flow ◽  
Ventilation System ◽  
Theoretical Expression ◽  
Air Flow Rate ◽  
Rate Testing ◽  
Fan Speed ◽  
The Impact

Based on air flow rate testing of each branch fan in a distributed fan ventilation system under different branch air duct inlet static pressures, the conclusion can be drawn that there is a branch fan air flow rate deviation phenomenon. The air flow rate of the branch fan increases with the branch air duct inlet static pressure at the same branch fan speed, and the branch fan hinders the air flow rate in some cases. In this study, a theoretical expression of the deviation of the branch air duct design air flow rate was established, and the influencing factors of the deviation were determined to include the branch air duct resistance characteristics, branch fan performance, and branch air duct inlet pressure ratio. A graphic analytical method for determining the deviation of the branch fan design air flow rate was also proposed. Both methods can provide a theoretical basis for calculating and analysing the deviation of the branch fan design air flow rate in a distributed fan ventilation system. Practical application: This paper provides new data on the performance of a distributed fan ventilation system. Our results could be used to evaluate the impact of distributed zone fans on the air flow rate in a mechanical ventilation system. Crucially, we not only propose two types of methods that can be applied to predict deviations of the air flow rate in a distributed fan ventilation system caused by the branch air duct inlet static pressures but also obtain the factors that are important for understanding the true impact of the deviation of the branch fan air flow rate. This study lays an important foundation for the design and operation of building mechanical ventilation systems.

scholarly journals Modelling and Simulation of Volume Controlled Mechanical Ventilation System

2014 ◽  
Vol 2014 ◽  
pp. 1-7 ◽  
Author(s):  
Yan Shi ◽  
Shuai Ren ◽  
Maolin Cai ◽  
Weiqing Xu
Keyword(s):  
Mathematical Model ◽  
Mechanical Ventilation ◽  
Respiratory System ◽  
Ventilation System ◽  
Delay System ◽  
Time Delay System ◽  
Typical Time ◽  
Controlled Mechanical Ventilation ◽  
The Mathematical Model ◽  
Volume Controlled

Volume controlled mechanical ventilation system is a typical time-delay system, which is applied to ventilate patients who cannot breathe adequately on their own. To illustrate the influences of key parameters of the ventilator on the dynamics of the ventilated respiratory system, this paper firstly derived a new mathematical model of the ventilation system; secondly, simulation and experimental results are compared to verify the mathematical model; lastly, the influences of key parameters of ventilator on the dynamics of the ventilated respiratory system are carried out. This study can be helpful in the VCV ventilation treatment and respiratory diagnostics.

scholarly journals Transcriptome profiling of the diaphragm in a controlled mechanical ventilation model reveals key genes involved in ventilator-induced diaphragmatic dysfunction

BMC Genomics ◽  
2021 ◽  
Vol 22 (1) ◽  
Author(s):  
Ruining Liu ◽  
Gang Li ◽  
Haoli Ma ◽  
Xianlong Zhou ◽  
Pengcheng Wang ◽  
...  
Keyword(s):  
Mechanical Ventilation ◽  
Signaling Pathway ◽  
Wistar Rats ◽  
Cholesterol Metabolism ◽  
Expression Profiles ◽  
Receptor Interaction ◽  
Pathophysiological Mechanism ◽  
Rna Seq ◽  
Diaphragmatic Dysfunction ◽  
Controlled Mechanical Ventilation

Abstract Background Ventilator-induced diaphragmatic dysfunction (VIDD) is associated with weaning difficulties, intensive care unit hospitalization (ICU), infant mortality, and poor long-term clinical outcomes. The expression patterns of long noncoding RNAs (lncRNAs) and mRNAs in the diaphragm in a rat controlled mechanical ventilation (CMV) model, however, remain to be investigated. Results The diaphragms of five male Wistar rats in a CMV group and five control Wistar rats were used to explore lncRNA and mRNA expression profiles by RNA-sequencing (RNA-seq). Muscle force measurements and immunofluorescence (IF) staining were used to verify the successful establishment of the CMV model. A total of 906 differentially expressed (DE) lncRNAs and 2,139 DE mRNAs were found in the CMV group. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) analyses were performed to determine the biological functions or pathways of these DE mRNAs. Our results revealed that these DE mRNAs were related mainly related to complement and coagulation cascades, the PPAR signaling pathway, cholesterol metabolism, cytokine-cytokine receptor interaction, and the AMPK signaling pathway. Some DE lncRNAs and DE mRNAs determined by RNA-seq were validated by quantitative real-time polymerase chain reaction (qRT-PCR), which exhibited trends similar to those observed by RNA-sEq. Co-expression network analysis indicated that three selected muscle atrophy-related mRNAs (Myog, Trim63, and Fbxo32) were coexpressed with relatively newly discovered DE lncRNAs. Conclusions This study provides a novel perspective on the molecular mechanism of DE lncRNAs and mRNAs in a CMV model, and indicates that the inflammatory signaling pathway and lipid metabolism may play important roles in the pathophysiological mechanism and progression of VIDD.

scholarly journals Effect of Mechanical Ventilation on Accidental Hydrogen Releases—Large-Scale Experiments

Energies ◽  
2021 ◽  
Vol 14 (11) ◽  
pp. 3008
Author(s):  
Agnieszka W. Lach ◽  
André V. Gaathaug
Keyword(s):  
Mechanical Ventilation ◽  
Mass Flow ◽  
Large Scale ◽  
Ventilation System ◽  
Hydrogen Gas ◽  
Forced Ventilation ◽  
British Standard ◽  
Confined Spaces ◽  
Series Of Experiments ◽  
Rate Limit

This paper presents a series of experiments on the effectiveness of existing mechanical ventilation systems during accidental hydrogen releases in confined spaces, such as underground garages. The purpose was to find the mass flow rate limit, hence the TPRD diameter limit, that will not require a change in the ventilation system. The experiments were performed in a 40 ft ISO container in Norway, and hydrogen gas was used in all experiments. The forced ventilation system was installed with a standard 315 mm diameter outlet. The ventilation parameters during the investigation were British Standard with 10 ACH and British Standard with 6 ACH. The hydrogen releases were obtained through 0.5 mm and 1 mm nozzles from different hydrogen reservoir pressures. Both types of mass flow, constant and blowdown, were included in the experimental matrix. The analysis of the hydrogen concentration of the created hydrogen cloud in the container shows the influence of the forced ventilation on hydrogen releases, together with TPRD diameter and reservoir pressure. The generated experimental data will be used to validate a CFD model in the next step.

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