scholarly journals Dynamic Analysis of the Natural and Mechanical Ventilation of a Solar Greenhouse by Coupling Controlled Mechanical Ventilation (CMV) with an Earth-to-Air Heat Exchanger (EAHX)

Energies ◽  
2020 ◽  
Vol 13 (14) ◽  
pp. 3676 ◽  
Author(s):  
Sara Bonuso ◽  
Simone Panico ◽  
Cristina Baglivo ◽  
Domenico Mazzeo ◽  
Nicoletta Matera ◽  
...  
Keyword(s):  
Mechanical Ventilation ◽  
Heat Exchanger ◽  
Dynamic Analysis ◽  
Air Conditioning ◽  
Well Being ◽  
Temperate Climate ◽  
Agricultural System ◽  
Transfer Coefficients ◽  
Solar Greenhouse ◽  
Controlled Mechanical Ventilation

Greenhouse crops represent a significant productive sector of the agricultural system; one of the main problems to be addressed is indoor air conditioning to ensure thermal well-being of crops. This study focuses on the ventilation analysis of solar greenhouse with symmetrical flat pitched roof and single span located in a warm temperate climate. This work proposes the dynamic analysis of the greenhouse modeled in TRNsys, simultaneously considering different thermal phenomena three-dimensional (3D) shortwave and longwave radiative exchange, airflow exchanges, presence of lamps with their exact 3D position, ground and plant evapotranspiration, and convective heat transfer coefficients. Several air conditioning systems were analyzed, automatic window opening, controlled mechanical ventilation systems (CMV) and horizontal Earth-to-Air Heat Exchanger (EAHX) coupled with CMV, for different air volume changes per hour. In summer, the exploitation of the ground allows having excellent results with the EAHX system, reducing the temperature peaks of up to 5 °C compared to the use of CMV. In winter, it is interesting to note that, although the EAHX is not the solution that raises the temperature the most during the day, its use allows flattening the thermal wave more. In fact, the trend is almost constant during the day, raising the temperature during the first and last hours of the day.

Analysis of Heat Pipe Heat Exchanger (HPHE) For Waste Heat Recovery from an Air Conditioning System

2007 ◽  
Vol 2 (3) ◽  
pp. 86-95
Author(s):  
R. Sudhakaran ◽  
◽  
V. Sella Durai ◽  
T. Kannan ◽  
P.S. Sivasakthievel ◽  
...  
Keyword(s):  
Heat Exchanger ◽  
Heat Pipe ◽  
Air Conditioning ◽  
Heat Recovery ◽  
Waste Heat Recovery ◽  
Waste Heat ◽  
Air Conditioning System ◽  
Pipe Heat

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.

Spiral-Plate Heat Exchanger Effectiveness With Equal Capacitance Rates

2005 ◽  
Author(s):  
Louis C. Burmeister
Keyword(s):  
Heat Exchanger ◽  
Plate Heat Exchanger ◽  
Close Approximation ◽  
Transfer Coefficients ◽  
Plate Heat ◽  
Heat Transfer Coefficients ◽  
Outer Periphery ◽  
Large Heat ◽  
The Difference ◽  
Spiral Plate

A formula is derived for the dependence of heat exchanger effectiveness on the number of transfer units for a spiral-plate heat exchanger with equal capacitance rates. The difference-differential equations that describe the temperature distributions of the two counter-flowing fluids, neglecting thermal radiation, are solved symbolically to close approximation. Provision is made for offset inlet and exit of the hot and cold fluids at the outer periphery and for large heat transfer coefficients in entrance regions. The peak effectiveness and the number of transfer units at which it occurs are predicted.

A Theoretical Model of Localized Heat and Water Vapor Transport in the Human Respiratory Tract

1986 ◽  
Vol 108 (1) ◽  
pp. 19-27 ◽  
Author(s):  
L. M. Hanna ◽  
P. W. Scherer
Keyword(s):  
Water Vapor ◽  
Theoretical Model ◽  
Respiratory Tract ◽  
Air Conditioning ◽  
High Stress ◽  
Vapor Transport ◽  
Water Vapor Transport ◽  
Upper Respiratory Tract ◽  
Transfer Coefficients ◽  
Human Respiratory Tract

A steady-state, one-dimensional theoretical model of human respiratory heat and water vapor transport is developed. Local mass transfer coefficients measured in a cast replica of the upper respiratory tract are incorporated into the model along with heat transfer coefficients determined from the Chilton-Colburn analogy and from data in the literature. The model agrees well with reported experimental measurements and predicts that the two most important parameters of the human air-conditioning process are: 1) the blood temperature distribution along the airway walls, and 2) the total cross-sectional area and perimeter of the nasal cavity. The model also shows that the larynx and pharynx can actually gain water over a respiratory cycle and are the regions of the respiratory tract most subject to drying. With slight modification, the model can be used to investigate respiratory heat and water vapor transport in high stress environments, pollutant gas uptake in the respiratory tract, and the connection between respiratory air-conditioning and the function of the mucociliary escalator.

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