scholarly journals An Overview of the Ship Ventilation Systems and Measures to Avoid the Spread of Diseases

Inventions ◽  
2021 ◽  
Vol 6 (3) ◽  
pp. 55
Author(s):  
Victor Mihai ◽  
Liliana Rusu
Keyword(s):  
Air Conditioning ◽  
Current Practice ◽  
High Efficiency ◽  
Local Heating ◽  
Uv Disinfection ◽  
Usual Practice ◽  
Air Supply ◽  
Different Types ◽  
Air Conditioning Systems ◽  
Ventilation Systems

This article presents a review of the main aspects regarding the current rules of classification societies, standards, and practice regarding the design and construction of ventilation and air conditioning systems for different compartments in different types of ships. In the context of the COVID-19 pandemic, this paper also presents the usual practice of the actual heating ventilation and air conditioning (HVAC) systems used on large ships, which recirculate the air between living compartments, in comparison with the new requirements to avoid the risk of spreading diseases. According to the rules, the technical compartments are provided with independent ventilation systems that ensure high air flow rates; therefore, the spread of diseases through this system is not an issue. The living spaces are provided with common ventilation and air conditioning systems that recirculate the air in all compartments served. The current practice of air recirculation in various living rooms leads to the spread of diseases, which should therefore be analyzed and improved by adding high-efficiency particulate air (HEPA) filters and UV disinfection or be replaced with individual systems that provide local heating or cooling without air recirculation between different rooms and fresh air supply with complete evacuation. For existing ships, different solutions should be analyzed such as reducing or cancelling recirculation and increasing filtration.

scholarly journals Research on Local Heating Regeneration Method for Air-Conditioning Systems

Processes ◽  
2021 ◽  
Vol 9 (3) ◽  
pp. 444
Author(s):  
Feng Cheng ◽  
Yunlei Wu ◽  
Xiuwei Li
Keyword(s):  
Air Conditioning ◽  
Local Heating ◽  
Solution Concentration ◽  
Regeneration Process ◽  
Future Application ◽  
Liquid Volume ◽  
Thermal Regeneration ◽  
Lower Efficiency ◽  
Good Potential ◽  
Air Conditioning Systems

Absorption air-conditioning systems have a great advantage in terms of energy conservation and environmental protection. However, the large amount of energy waste in the thermal regeneration process leads to lower efficiency and impedes its development. To reduce energy loss and improve performance, a local heating regeneration method is proposed in this paper. The main principle is reducing the volume of the liquid participating regeneration. Including the solar steam mode, two modes are introduced and configured. Theoretical and experimental research has been made on the new methods. Models have been developed for comparison analysis. Experiments have been conducted on water and absorbent solution with different modes. Performance has been evaluated based on the experimental data. The results expose the influence of different parameters, like liquid volume and solution concentration, on the regeneration process. The local heating method improved the regeneration efficiency by 40% in the no solar steam mode and the performance tripled in the solar steam mode. The COP (the ratio of cooling load to energy consumption) of the absorption system with the solar steam mode is more than two times of that with the traditional regeneration mode. It shows the local heating regeneration method has good potential in future application.

Effect of Air Conditioning Position on Thermal Comfort in the Floor Air Conditioning System

2014 ◽  
Vol 493 ◽  
pp. 74-79
Author(s):  
Y.A. Sabtalistia ◽  
S.N.N. Ekasiwi ◽  
B. Iskandriawan
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Energy Consumption ◽  
Thermal Comfort ◽  
Energy Efficient ◽  
Air Conditioning ◽  
Air Conditioning System ◽  
Air Supply ◽  
Air Conditioning Systems ◽  
Air Diffusion

Energy consumption for air conditioning systems (air conditioning system) increased along with the increasing need for fresh air and comfortable in the room especially apartments. FAC system (Floor Air Conditioning) is growing because it is more energy efficient than CAC (Ceiling Air Conditioning) system. However, the position of the AC supply is on the lower level at the FAC system causes draft discomfort becomes greater as air supply closer to the occupants so that thermal comfort can be reduced. Heat mixture of windows, exterior walls, kitchen, and occupants in the studio apartment affect thermal comfort in the room too.This study aims to determine the position of the AC supply which has the best thermal comfort of FAC system in the studio apartment. It can be done by analyzing ADPI (Air Diffusion Performance Index), the distribution of air temperature, wind speed, RH (Relative Humidity), and DR (Draft Risk) to change the position of the AC supply supported by CFD (Computational Fluid Dynamics) simulation.This result prove that AC position 2 (on wall near the kitchen) is more comfortable than AC position 1 (on the bathroom wall) because AC position 2 away from occupied areas, thereby reducing the occurrence of draught discomfort.

Thermal Comfort Analysis of a Ship Air-Conditioning System Using Solidworks Flow Simulation

2013 ◽  
Vol 773 ◽  
pp. 883-888 ◽  
Author(s):  
Hamid Nawaz ◽  
Yan Sheng Yuan
Keyword(s):  
Thermal Comfort ◽  
Air Conditioning ◽  
Flow Simulation ◽  
Simulation Software ◽  
Air Conditioning System ◽  
Air Supply ◽  
Different Types ◽  
Design Software ◽  
Selection Of ◽  
Occupied Zone

The focus of this work is to simulate and optimize thermal comfort in a ship air-conditioning system by evaluating the performance of different types of air supply outlets. Thermal comfort analyses were performed in Solidworks Flow Simulation software by changing the number, type and position of air supply outlets and the comfort was optimized by evaluating the values of temperature, velocity, PMV (Predicted mean vote) & PPD (Predicted Percentage Dissatisfied). It was concluded from the results obtained from different analyses that air supply outlet is a vital part in any type of HVAC (Heating ventilation & air conditioning) system design, as its number, type and position has significant effect on the air distribution and thermal comfort in a subject space. It was also deduced that improper selection of air supply outlet can result in room air stagnation, unacceptable temperature gradients, and undesirable velocities in the occupied zone that may lead to occupant discomfort. Through this work the importance and effectiveness of CFD (computational fluid dynamics) design tools, in the design & optimization of HVAC systems has been evaluated and it was concluded that CFD design software like Solidworks flow simulation provide an excellent provision to validate different aspects of HVAC design before actual construction.

Spreading of SARS-CoV-2 via Heating, Ventilation, and Air Conditioning Systems—An Overview of Energy Perspective and Potential Solutions

2020 ◽  
Vol 143 (8) ◽  
Author(s):  
Ahmad K. Sleiti ◽  
Samer F. Ahmed ◽  
Saud A. Ghani
Keyword(s):  
Air Conditioning ◽  
High Performance ◽  
Public Perception ◽  
High Efficiency ◽  
Uv Light ◽  
Experimental Studies ◽  
High Energy ◽  
Penalty Cost ◽  
Energy Penalty ◽  
Air Conditioning Systems

Abstract The role of heating, ventilation, and air conditioning systems (HVAC) in spreading SARS-CoV-2 is a complex topic and has not been studied thoroughly. There are some existing strategies and technologies for health and high performance buildings; however, applications to other types of buildings come at large energy penalty: cost; design, regulations and standards changes, and varied public perception. In the present work, different factors and strategies are reviewed and discussed and suggested mitigations and solutions are provided including the required air flowrates with the presence of infectors with and without mask and disinfection techniques including ultraviolet (UV) light. Experimental and numerical research in open literature suggests that the airborne transmission of SARS-CoV-2 is sufficiently likely. However, in situ detailed experimental studies are still needed to understand the different scenarios of the virus spread. Displacement ventilation, underfloor air distribution, chilled beams, radiant ceiling panels, and laminar flow systems have varied effectiveness. High-efficiency particulate arrestance (HEPA) filters and UV light can clean viruses but at high energy cost. Suggested solutions to reduce the infection probability include recommended levels of ventilation and a combination of virus sampling technologies including cyclones, liquid impinger, filters, electrostatic precipitators, and water-based condensation.

Application of Computational Fluid Dynamics (CFD) Used in Simulation of Flow Distribution for Air Condition

2013 ◽  
Vol 278-280 ◽  
pp. 111-116
Author(s):  
Zheng Zhang ◽  
Jin Feng Wang ◽  
Jing Xie ◽  
Yi Tang
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Energy Saving ◽  
Theoretical Basis ◽  
Air Conditioning ◽  
Flow Distribution ◽  
Research Progress ◽  
Air Supply ◽  
Computational Fluid Dynamics Cfd ◽  
Air Conditioning Systems

In this article, the application of Computational Fluid Dynamics (CFD) technology in the field of Heating Ventilation & Air Condition was introduced, and the research progress in optimizing the simulation of air-conditioned room was summarized. Some domestic and foreign studies on air conditioning operation and energy saving were illustrated about the effects of different installation locations, blow angles and air supply modes, which would provide a theoretical basis and scientific guidance for air-conditioning systems to optimize the design. Based on previous results, the development of further research on CFD in the simulation of air-conditioning in future was analyzed.

scholarly journals Impact Assessment of the ventilation systems on microbiological safety and microclimatic conditions of premises.

2020 ◽  
pp. 49-55
Author(s):  
Tetiana Kryvomaz ◽  
Dmytro Varavin ◽  
Rostyslav Sipakov
Keyword(s):  
Air Conditioning ◽  
Residential Buildings ◽  
Operating Conditions ◽  
International Agencies ◽  
Industrial Buildings ◽  
Key Factor ◽  
Poor Ventilation ◽  
Air Conditioning Systems ◽  
The Impact ◽  
Ventilation Systems

The critical aspects of the impact of microbiological contamination on ventilation and air conditioning systems, the microclimate of the premises, and human health are analyzed. The quantitative and qualitative composition of the microflora of premises depends on their functional purpose, design features, operating conditions, climate, and other factors, among which the method of ventilation is essential. The moisturizers in the air conditioning system are hazardous, which provide bacteria and fungi with water necessary for their life and reproduction. In addition, contaminants accumulated in ventilation systems operate as a substrate for feeding microorganisms. Multi-story administrative, public, and residential buildings, industrial buildings, and other places of mass concentration are areas of increased aerobiological risk of infection. In case of improper operation, air conditioning and ventilation systems can be sources of microorganisms in any room. Transmission of infectious aerosol over long distances occurs in rooms with poor ventilation, and a key factor for the outbreak of infection is the direction of airflows. In the context of the COVID-19 pandemic, organizations and international agencies to control the spread of SARS-CoV-2 indoors recommend limiting the operation of exhaust ventilation and recirculation systems. However, there is still insufficient data to clarify the role of heating, ventilation, and air conditioning systems in spreading infection. Risk assessment and decision-making on the choice of air conditioning systems should be dynamic and based on the scale of the pandemic and the verification of the characteristics of HVAC systems and their effectiveness.

scholarly journals Effects of air-conditioning systems in the public areas of hospitals: A scoping review

2021 ◽  
Vol 149 ◽  
Author(s):  
Han Ting Wu ◽  
Qiu Shuang Li ◽  
Rong Chen Dai ◽  
Shan Liu ◽  
Li Wu ◽  
...  
Keyword(s):  
Scoping Review ◽  
Air Conditioning ◽  
Microbial Contamination ◽  
High Efficiency ◽  
Cross Sectional ◽  
The Public ◽  
Public Areas ◽  
Almost All ◽  
Air Conditioning Systems ◽  
The Impact

Abstract Almost all hospitals are equipped with air-conditioning systems to provide a comfortable environment for patients and staff. However, the accumulation of dust and moisture within these systems increases the risk of transmission of microbes and have on occasion been associated with outbreaks of infection. Nevertheless, the impact of air-conditioning on the transmission of microorganisms leading to infection remains largely uncertain. We conducted a scoping review to screen systematically the evidence for such an association in the face of the coronavirus disease 2019 epidemic. PubMed, Embase and Web of Science databases were explored for relevant studies addressing microbial contamination of the air, their transmission and association with infectious diseases. The review process yielded 21 publications, 17 of which were cross-sectional studies, three were cohort studies and one case−control study. Our analysis showed that, compared with naturally ventilated areas, microbial loads were significantly lower in air-conditioned areas, but the incidence of infections increased if not properly managed. The use of high-efficiency particulate air (HEPA) filtration not only decreased transmission of airborne bioaerosols and various microorganisms, but also reduced the risk of infections. By contrast, contaminated air-conditioning systems in hospital rooms were associated with a higher risk of patient infection. Cleaning and maintenance of such systems to recommended standards should be performed regularly and where appropriate, the installation of HEPA filters can effectively mitigate microbial contamination in the public areas of hospitals.

Resistance Coefficient Research of the Train Air Supply Orifice

2012 ◽  
Vol 614-615 ◽  
pp. 475-479
Author(s):  
Hai Ying Wang ◽  
Chun Fang Li ◽  
Song Tao Hu ◽  
Lin Song
Keyword(s):  
Experimental Study ◽  
Temperature Field ◽  
Air Conditioning ◽  
High Speed ◽  
Plate Thickness ◽  
Resistance Coefficient ◽  
High Speed Train ◽  
Air Conditioning System ◽  
Air Supply ◽  
Air Conditioning Systems

High-speed train air-conditioning systems put forward higher request on the aspect of air uniformity and comfort. The use of orifice which can form a more uniform velocity and temperature field in the car can be widely applied to high-speed train air-conditioning system. The experimental study of the influence of several different factors (such as the opening rate, aperture, orifice plate thickness, etc.) in the research may provide a reference for the design choices of the orifice type.

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