The impact of air filter pressure drop on the performance of typical air-conditioning systems

2012 ◽  
Vol 5 (4) ◽  
pp. 345-350 ◽  
Author(s):  
Nabil Nassif
Keyword(s):  
Pressure Drop ◽  
Air Conditioning ◽  
Air Filter ◽  
Air Conditioning Systems ◽  
The Impact

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.

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 Mixing Effectiveness of Various Damper-Plenum Configurations

2008 ◽  
Vol 42 (2008) ◽  
pp. 18-22 ◽  
Author(s):  
H. J. Sauer ◽  
P. Hande ◽  
F. Finaish
Keyword(s):  
Pressure Drop ◽  
Air Conditioning ◽  
Energy Use ◽  
Scale Validation ◽  
Velocity Ratio ◽  
Mixing Performance ◽  
Mixing Box ◽  
American Society ◽  
Air Conditioning Systems ◽  
Air Streams

Improper mixing of outside air and return air streams in building air conditioning systems has been recognized for years. The problems may lead to nuisance cycling, frequent freeze-stat trips and serious consequences of a frozen or ruptured conditioning coil. It was thought that typical solutions for the problem usually consist of preferred placement of outside air and return air duct penetrations to the mixing box, manipulation of the inlet damper angles and velocity ratio between the outside air and return air streams and the insertion of static flow mixers in the mixing box to help improve the thermal stratification. This paper reports the results of a computational fluid dynamics (CFD) study conducted as a follow-up to an experimental study conducted at the Ruskin Laboratory in Grandview, Missouri, sponsored by the American Society of Heating, Refrigerating and Air-Conditioning Engineers (ASHRAE). The CFD results indicated that the most significant improvement in mixing performance with minimum increase in pressure drop and energy use is achieved by expanding the mixing plenum. Effectiveness increased from 39 percent to 67 percent with less than a 0.1 inch of water additional pressure drop. However, optimization of relative plenum dimensions and baffle size and placement awaits additional CFD simulations and full scale validation.

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.

scholarly journals Thermal analysis of car air conditioning

2010 ◽  
Vol 31 (4) ◽  
pp. 71-80 ◽  
Author(s):  
Daniel Trzebiński ◽  
Ireneusz Szczygieł
Keyword(s):  
Thermal Analysis ◽  
Thermodynamic Analysis ◽  
Air Temperature ◽  
Air Conditioning ◽  
Expansion Valve ◽  
Air Cooler ◽  
Air Conditioning Systems ◽  
The Impact

Thermal analysis of car air conditioningThermodynamic analysis of car air cooler is presented in this paper. Typical refrigerator cycles are studied. The first: with uncontrolled orifice and non controlled compressor and the second one with the thermostatic controlled expansion valve and externally controlled compressor. The influence of the refrigerant decrease and the change of the air temperature which gets to exchangers on the refrigeration efficiency of the system; was analysed. Also, its effectiveness and the power required to drive the compressor were investigated. The impact of improper refrigerant charge on the performance of air conditioning systems was also checked.

Study on the Current Situation of Economic Analysis of Ice Storage Air-Conditioning System

2014 ◽  
Vol 580-583 ◽  
pp. 2441-2446
Author(s):  
Yu Na Li ◽  
Si Fu Wang ◽  
Tu Zhai Lv ◽  
Shao Fei Lang
Keyword(s):  
Economic Evaluation ◽  
Economic Analysis ◽  
Air Conditioning ◽  
Current Situation ◽  
Ice Storage ◽  
Economic Factors ◽  
Analysis Model ◽  
Air Conditioning System ◽  
Air Conditioning Systems ◽  
The Impact

Ice storage air-conditioning system has incomparable advantages than a lot of of conventional air-conditioning system example for "peak shifting and valley filling". The ice storage air-conditioning systems on the research states of the economic analysis are summed up from the building of economic analysis model,the introduction of the special systems , as well as the impact of economic factors in this paper. This paper outlines several main methods about economic evaluation of the ice storage air-conditioning systems,points out some issumes in the course of the study and some places needing to improve.

scholarly journals F-Gas regulation-Possible solutions for the retrofit dead end

2018 ◽  
Vol 178 ◽  
pp. 09023
Author(s):  
Filipe Gonçalves ◽  
Miguel Cavique
Keyword(s):  
Heat Exchangers ◽  
Air Conditioning ◽  
Refrigeration Cycle ◽  
Refrigeration System ◽  
Air Conditioning System ◽  
Dead End ◽  
Air Conditioning Systems ◽  
The Impact ◽  
Maintenance Problem ◽  
The Eu

The EU F-gas regulation of 2006 and the recast of 2014 are forcing the market to reduce the use of refrigerants with high global warming potential (GWP). As a result, the production of hydrofluorocarbon (HFC) refrigerants with higher GWP decreased, making the prices of all HFC gases to increase. Any maintenance problem in a refrigeration system asks to evaluate the retrofitting of the gas making necessary to know the expected behaviour of the system. This paper aims to discuss the gases that can substitute the now-a-days HFCs, and the impact the retrofit will cause in a real air-conditioning systems. Many studies on retrofit address the behaviour of the refrigeration cycle, but usually, do not take into account the behaviour of the system as a whole. This paper models a water-to-water air-conditioning system taking into consideration the evaporator and condenser heat exchangers, the refrigeration cycle, the air-conditioning loop and the heat exchanger to the acclimatized area. Moreover, the paper studies the performance of the system when subjected to high condensing temperatures. The paper concludes that all possible retrofit solutions need to use flammable gases that make the refrigeration power of the equipment to reduce.

A Uniquely Finned Tube Heat Exchanger Design of a Condenser for Heavy-Duty Air Conditioning Systems

2020 ◽  
Vol 28 (01) ◽  
pp. 2050004 ◽  
Author(s):  
Ahmad M. Abubaker ◽  
Yousef S. H. Najjar ◽  
Adnan Darwish Ahmad
Keyword(s):  
Heat Exchanger ◽  
Pressure Drop ◽  
Air Conditioning ◽  
Water Pressure ◽  
Unit Length ◽  
Finned Tube ◽  
Coefficient Of Performance ◽  
Tube Heat Exchanger ◽  
Finned Tube Heat Exchanger ◽  
Air Conditioning Systems

This study introduces the design of a novel condenser for air conditioning systems. Enhancement of performance of the system was manifested by increasing the coefficient of performance (COP), decreasing the pressure drop and the power consumed by the refrigerant compressor and the cooling water pump. The design consists of an adiabatic double-pipe heat exchanger with longitudinal rectangular fins. This model can enhance heat transfer coefficient and expose more area per unit length. This novel design supersedes other conventional condenser designs by 4.7% higher COP, 8.2% lower water pressure drop, 4.68% lower compressor power. Two refrigerants have been examined in the study; R-134a which is used in commercial and industrial chillers and R-1234ze which has low global warming potential.

scholarly journals Estimation of the efficiency of the treatment of split-systems in residential areas in order to reduce the level of the prevalence of diseases of the respiratory system

2019 ◽  
Vol 95 (4) ◽  
pp. 325-329 ◽  
Author(s):  
Yu. A. Rakhmanin ◽  
S. E. Shibanov ◽  
Sergey V. Kozulya
Keyword(s):  
Air Conditioning ◽  
Subsequent Development ◽  
Morbidity Rate ◽  
Control Group ◽  
Residential Areas ◽  
Normative Documents ◽  
Regular Treatment ◽  
Split Systems ◽  
Air Conditioning Systems ◽  
The Impact

The purpose of work: comparison of prevalence among residents, which use or fail to use to clean split systems. Materials and methods. Collected information about morbidity rate in 235 cases people during 3 years. Results. The usage of split-systems without their regular cleaning leads to the gain in the level of the prevalence of respiratory diseases by 172.7% if compared with persons, who have no air conditioning systems at home. Also, the average number of disability days increases by 218.1%) and average time of the duration of the disease increases by 71.9%. The annual treatment of split-systems and regular cleaning offilters allowed to reduce the number of diseases. In comparison with the group of people, who fail to clean air conditioning systems, the drop of morbidity rate by 56.6%, average number of disability days by 63.3% and average time of diseases by 30.9% was observed. Regular treatment of air conditioning systems cannot completely repay the morbidity rates to the level of the control group. In comparison with the people, who use no air conditioning systems, the owners of split-systems with regular treatment have lung diseases by 18.4% more often. The average number of disability days and the average time of diseases increased by 16.9% and 18.8%. These changes can be explained by the impact of unfavorable (cooling) microclimate. Conclusions. The impact of split-systems on the health of the population requires a comprehensive study and the subsequent development of normative documents regulating their safe use.

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