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

2020 ◽  
Vol 35 ◽  
pp. 49-61
Author(s):  
T. Kryvomaz ◽  
D. Varavin ◽  
R. Sipakov ◽  
R. Kuzmishina
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 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.

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

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.

scholarly journals Determination of conditions for spontaneous combustion of combustible dust deposits on equipment, in ventilation systems, and aspiration systems of buildings and structures

2020 ◽  
Vol 29 (4) ◽  
pp. 32-41
Author(s):  
L. P. Vogman ◽  
D. A. Korolchenko ◽  
A. V. Khryukin
Keyword(s):  
Spontaneous Combustion ◽  
Growth Dynamics ◽  
Operating Conditions ◽  
Industrial Enterprises ◽  
Process Characteristics ◽  
Industrial Buildings ◽  
Dust Deposits ◽  
Production Facilities ◽  
Ventilation Systems

Introduction. Determination of the scientifi cally substantiated frequency of cleaning the ducts of local exhausts of industrial buildings and structures is one of the tasks in the fi eld of fi re safety of industrial enterprises. The paper describes design methods, in particular, a method for determination of the induction period during spontaneous combustion of dust deposits in air ducts of ventilation systems and equipment, which can be used in solving problems focused on the development of preventive measures to ensure their fi re and explosion safety.Methods. In order to solve the problem set in this paper and compare the indicators obtained in the calculation and analytical part of the studies with the growth dynamics of deposits in real facilities, fi eld tests have been accomplished in the production facilities of the fl our mill of OJSC MK “Voronezhsky” and JSC Concern “Sozvezdiye”.Results and discussion. The timeframes for cleaning of deposits on ventilation (aspiration) equipment of buildings and structures cannot be universal for various industries and must take into account the dynamics of the growth of deposits depending on the specifi cs of combustible deposits, the workload of the production facilities of the protected object in a given period of time, and the operating conditions of the equipment. As a result of the experiments, it was found that the places of maximum accumulations of deposits are most often formed on the surfaces of joints and on the bends of pipelines of ventilation systems. The conditions of spontaneous combustion of combustible dust are studied by calculation and analytical method, depending on such process characteristics as the speed of the dust-air mixture fl ow in the duct, as well as the diameter of the duct’s cross section.Conclusions. The nomograms built on the basis of the studies performed can be used to determine the multiplicity of cleaning of combustible dusts of equipment and air ducts of industrial ventilation systems. The paper provides a calculation of the period of induction of spontaneous combustion of combustible dust deposits using the example of rye fl our with asymmetric heat transfer. Its signifi cance is due to the process of accumulation of deposits of combustible dust to a critical thickness in terms of spontaneous combustion conditions.

scholarly journals The impact of thermal comfort in the perceived level of service and energy costs of three Brazilian airports

2013 ◽  
Vol 7 (2) ◽  
pp. 192-206 ◽  
Author(s):  
Jacqueline Elhage Ramis ◽  
Emmanuel Antonio dos Santos
Keyword(s):  
Thermal Comfort ◽  
Air Conditioning ◽  
International Standards ◽  
Combined System ◽  
Service Levels ◽  
Transportation Demand ◽  
Temperature And Humidity ◽  
Air Conditioning Systems ◽  
Air Circulation ◽  
The Impact

To evaluate airports' current thermal comfort temperature and humidity were registered in three main Brazilian international airports, other variables were local region climate characteristics and the constructive types of passenger terminal buildings. The Brazilian air transportation demand has considerably grown over the last decade, with some airports reaching their capacity. Thermal discomfort may be a key driver of passenger perceptions of airport service levels, specially under capacity overload situations. Therefore, to achieve airport thermal comfort within this new scenario, and with the imminent and future expansions of the airport system, certainly put extra work on the existing air conditioning systems, consequently increasing energy consumption and its associated costs. Collected temperature and humidity from each study case subsided the data for the psychrometric charts. The evidences showed temperatures below the international standards requirements for thermal comfort levels. These charts also indicated that adequate building types with natural air circulation, provides the best levels of thermal comfort. Results suggest the importance of considering the implementation of a combined system using artificial and natural air conditioning in the planning of future expansions.

Analysis of the Behavior of an Air Conditioning System Based on the Solar Energy Natural Regulation in Amazonian Climatic Conditions

2020 ◽  
Vol 143 (3) ◽  
Author(s):  
Elson C. Santos ◽  
Emanuel N. Macêdo ◽  
Marcos A. B. Galhardo ◽  
Thiago Oliveira Costa ◽  
André Felipe P. Costa ◽  
...  
Keyword(s):  
Direct Current ◽  
Air Conditioning ◽  
Cooling Capacity ◽  
Climatic Conditions ◽  
Power Modeling ◽  
Frequency Converters ◽  
Industrial Buildings ◽  
Air Conditioning Systems ◽  
Solar Resource ◽  
Installed Capacity

Abstract Air conditioning systems (ACSs) represent one of the main demands for electricity in residential, commercial, and industrial buildings. The use of a photovoltaic air conditioning unit (PVACU) represents an attractive application to this demand for reasons such as environmental concerns and the match between diurnal cooling load and solar resource. A PVACU consists of a photovoltaic generator (PVG) that supply an ACS through direct current to direct current and frequency converters, without energy storage. This system considers the natural adjustment of the ACS cooling capacity according to the PVG power. Modeling the ACS, the PVG, and the thermal load (TL) makes possible to evaluate PVACU performance. For this, a small library’s TL and an ACS supplied by a PVG were used as case study. The PVG installed capacity assumes values of 700, 1000, and 1400 Wp. The simulation results show that the PVACU with a 1400 Wp PVG would be sufficient to regulate internal temperature within international comfort standards in the range of 20 °C to 24 °C. According to the data obtained in the simulations, it was possible to conclude that the PVACU has a large potential to be used in air conditioning of other environments in regions with Amazonian climatic conditions.

Performance Analysis of an Air Drier for a Liquid Dehumidifier Solar Air Conditioning System

1988 ◽  
Vol 110 (2) ◽  
pp. 120-124 ◽  
Author(s):  
A. G. Queiroz ◽  
A. F. Orlando ◽  
F. E. M. Saboya
Keyword(s):  
Mass Transfer ◽  
Air Conditioning ◽  
Water Vapor Pressure ◽  
Triethylene Glycol ◽  
Operating Conditions ◽  
Integral Approach ◽  
Air Conditioning System ◽  
Air Conditioning Systems ◽  
Glycol Solution ◽  
Transfer Potential

A model was developed for calculating the operating conditions of a non-adiabatic liquid dehumidifier used in solar air conditioning systems. In the experimental facility used for obtaining the data, air and triethylene glycol circulate countercurrently outside staggered copper tubes which are the filling of an absorption tower. Water flows inside the copper tubes, thus cooling the whole system and increasing the mass transfer potential for drying air. The methodology for calculating the mass transfer coefficient is based on the Merkel integral approach, taking into account the lowering of the water vapor pressure in equilibrium with the water glycol solution.

scholarly journals The influence of air conditioning changes on the effective dose due to radon and its short-lived decay products

Nukleonika ◽  
2016 ◽  
Vol 61 (3) ◽  
pp. 239-244
Author(s):  
Dominik Grządziel ◽  
Krzysztof Kozak ◽  
Jadwiga Mazur ◽  
Bernard Połednik ◽  
Marzenna R. Dudzińska ◽  
...  
Keyword(s):  
Effective Dose ◽  
Air Conditioning ◽  
Indoor Environments ◽  
Radon Progeny ◽  
Inhalation Dose ◽  
Decay Products ◽  
Air Supply ◽  
Industrial Buildings ◽  
The Mean ◽  
The Impact

Abstract Most people spend the majority of their time in indoor environments where the level of harmful pollutants is often significantly higher than outdoors. Radon (222Rn) and its decay products are the example of radioactive pollutants. These radioisotopes are the main source of ionizing radiation in non-industrial buildings. The aim of the study was to determine the impact of air-conditioning system on radon and its progeny concentrations and thus on the effective dose. The measurements were carried out in the auditorium at the Environmental Engineering Faculty (Lublin University of Technology, Poland). Measurements of radon and its progeny (in attached and unattached fractions) as well as measurements of the following indoor air parameters were performed in two air-conditioning (AC) operation modes: AC ON and AC ON/OFF. The air supply rate and air recirculation were taken into consideration. The separation of radon progeny into attached and unattached fractions allowed for determining, respectively, the dose conversion factor (DCF) and the inhalation dose for teachers and students in the auditorium. A considerable increase of the mean radon progeny concentrations from 1.2 Bq/m3 to 5.0 Bq/m3 was observed in the AC ON/OFF mode compared to the AC ON mode. This also resulted in the increase of the inhalation dose from 0.005 mSv/y to 0.016 mSv/y (for 200 h/year). Furthermore, the change of the air recirculation rate from 0% to 80% resulted in a decrease of the mean radon concentration from 30 Bq/m3 to 12 Bq/m3 and the reduction of the mean radon progeny concentration from 1.4 Bq/m3 to 0.8 Bq/m3. This resulted in the reduction of the inhalation dose from 0.006 mSv/y to 0.003 mSv/y.

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