Type and Density of Bacterial and Fungal Bioaerosols and Particles in Inside and Outside of Hospital: Modeling of Dispersion and Antibiotic Resistance of Bacterial Bioaerosols

Abstract The study of loading rate of microorganisms in the space of hospital inside and outside to evaluate their impacts on physical health of patients and staff, as well as to find out the source of possible infections and allergies stemming from the presence of bioaerosols is of great importance. In total, 262 bacterial and fungal samples were collected from the air of the wards of Tohid Hospital, Sanandaj, Iran. Also, suspended particles were measured by Particle Mass Counter (model: TES-5200). Parameter such as relative humidity and temperature were recorded by using TES-5200 device. To identify bacteria, some biochemical and molecular tests were conducted. And, for the identification of fungi, microscopic and macroscopic characteristics were used. The highest and lowest densities of the bioaerosols were observed in lung and operating wards (336.67 and 15.25 CFU/m3). Moreover, the highest and least concentrations of particles were seen in the emergency and operating wards, respectively. The most common fungi isolated from the hospital air were Penicillium (24.7%), Cladosporium (23. 4%), Aspergillus niger (13.3%) and Aspergillus Flavus (11.4%). Furthermore, the highest concentration of the isolated bacterium was Staphylococcus hemolyticus (31.84%). And, the bacteria had the most resistance to antibiotic gentamicin.The general average of air pollution of the hospital to bioaerosols in quantitative terms was higher than that suggested by international organizations. Considering the high concentration of bioaerosols and particles in the hospital studied, provision of optimal conditions (like temperature, humidity, suitable ventilation and intelligent air conditioning system) and imposing a restriction in the entrance of the wards can be utilized to reduce the amount of pollution.

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Performance evaluation of the electrodialysis regenerator for the lithium bromide solution with high concentration in the liquid desiccant air-conditioning system

Energy ◽

10.1016/j.energy.2019.115928 ◽

2019 ◽

Vol 187 ◽

pp. 115928 ◽

Cited By ~ 3

Author(s):

Wang Pei ◽

Qing Cheng ◽

Shun Jiao ◽

Lin Liu

Keyword(s):

Performance Evaluation ◽

Air Conditioning ◽

Lithium Bromide ◽

Liquid Desiccant ◽

High Concentration ◽

Air Conditioning System ◽

Bromide Solution ◽

Lithium Bromide Solution

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Thermal energy analysis on liquid desiccant air conditioning system at different desiccant solution parameters

Proceedings of the Institution of Mechanical Engineers Part E Journal of Process Mechanical Engineering ◽

10.1177/0954408919825721 ◽

2019 ◽

Vol 233 (5) ◽

pp. 1052-1065

Author(s):

Y Siva Kumar Reddy ◽

Karthik Balasubramanian ◽

VP Chandramohan

Keyword(s):

Heat Capacity ◽

Thermal Energy ◽

Air Conditioning ◽

Energy Analysis ◽

Operating Parameters ◽

Liquid Desiccant ◽

High Concentration ◽

Air Conditioning System ◽

Capacity Ratio ◽

Solution Parameters

Selection of suitable liquid desiccant operating parameters plays a significant role in the design of energy efficient liquid desiccant air conditioning system. To achieve same dehumidification rate from ambient air, different combinations of solution parameters (heat capacity ratio, concentration, and vapor pressure) could be employed in the system. Considering dehumidifier air inlet condition and dehumidification rates are fixed, an analytical study is carried out on the thermal energy analysis of the system at different solution operating parameters. Operating parameters considered in this study are solution concentrations ( Cs = 0.25, 0.3, 0.35 and 0.40) and heat capacity ratios ([Formula: see text] = 2.5, 3, 4 and 5). Control volume which includes a pair of air and solution channels (half width channels) of full scale liquid-to-air membrane energy exchangers (LAMEE) has been chosen to analyze the energy transfer between air and solution. The results indicate system requires lesser chiller load ( Qchiller) at high concentration and low heat capacity ratio ( Cs = 0.40 and [Formula: see text] = 2.5) which is 0.29 kW to achieve 0.61 kW cooling load. This is 99% lesser than the Qchiller at high concentration and high heat capacity ratio ( Cs = 0.40 and [Formula: see text] = 5) and 30% lesser than the Qchiller at low concentration and low heat capacity ratio ( Cs = 0.25 and [Formula: see text] = 2.5). Solution heat addition rate ( Qadd) per kW cooling capacity ( Qcc) at this solution condition is found as 0.85 kW.

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Experimental Research on Regeneration Characteristic of ED Regeneration for Lithium Bromide Desiccant Solution with High Concentration: Operating Condition and Electrode Solution

Energies ◽

10.3390/en13184733 ◽

2020 ◽

Vol 13 (18) ◽

pp. 4733

Author(s):

Qing Cheng ◽

Han Wang

Keyword(s):

Flow Rate ◽

Air Conditioning ◽

Lithium Bromide ◽

Solution Concentration ◽

Regeneration System ◽

High Concentration ◽

Air Conditioning System ◽

Initial Concentration ◽

Libr Solution ◽

Short Time

Electrodialysis is regarded as a novel liquid regeneration method, and the regenerated solution can satisfy the dehumidification requirements even in a hot and humid environment. LiBr solution is an important choice for a liquid desiccant air conditioning system due to its great dehumidifying ability, so it is necessary to conduct experimental exploration of the regeneration characteristics of ED regeneration for LiBr solution. In this paper, the effects of solution concentration, circulation flow rate, current and electrode solution on the performance of the electrodialysis regeneration system were studied by constructing an experimental electrodialysis regeneration system. The results show that growing the starting concentration of the LiBr solution adversely affects the regeneration characteristics of the electrodialyzer and of the air conditioning system dehumidified by the solution. Under test conditions, as the initial concentration of LiBr solution increased from 45% to 55%, the performance coefficient (COP) of the system decreased from 2.12 to 1.05. When the dehumidification requirement is met, the initial concentration of the LiBr solution should be reduced. Increasing the circulating flow rate can improve the regeneration performance of the electrodialyzer and the capability of the air conditioning system dehumidified by the solution, but excessively increasing the circulating flow rate will decrease the regeneration performance of the electrodialyzer and the performance of the air conditioning system dehumidified by the solution. Increasing the current can increase the concentration of the LiBr solution in the regeneration cells in a short time, but it will reduce the regeneration performance of the electrodialyzer and the characteristic of the air conditioning system dehumidified by the solution. The current needs to be minimized when meeting regeneration requirements. With the growth in the flow rate of the electrode solution, the regeneration performance of the electrodialyser decreases continuously.

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ANALYSIS OF COMPETING VARIANTS OF AIR CONDITIONING SYSTEMS WITHOUT AIR EXTRACTION FROM ENGINES AT THE STAGE OF PASSENGER AIRCRAFT ONBOARD SYSTEMS CONCEPTUAL DESIGN

Computational nanotechnology ◽

10.33693/2313-223x-2019-6-3-86-91 ◽

2019 ◽

Vol 6 (3) ◽

pp. 80-85

Author(s):

Denis Igorevich Smagin ◽

Konstantin Igorevich Starostin ◽

Roman Sergeevich Savelyev ◽

Anatoly Anatolyevich Satin ◽

Anastasiya Romanovna Neveshkina ◽

...

Keyword(s):

Conceptual Design ◽

Air Conditioning ◽

Research University ◽

Cooling System ◽

Fuel Efficiency ◽

Air Cooling ◽

Moscow Aviation Institute ◽

Air Conditioning System ◽

Low Efficiency ◽

Air Conditioning Systems

One of the ways to achieve safety and comfort is to improve on-board air conditioning systems.The use of air cooling machine determines the air pressure high level at the point of selection from the aircraft engine compressor. Because of the aircraft operation in different modes and especially in the modes of small gas engines, deliberately high stages of selection have to be used for ensuring proper operation of the refrigeration machine in the modes of the aircraft small gas engines. Into force of this, most modes of aircraft operation have to throttle the pressure of the selected stage of selection, which, together with the low efficiency of the air cycle cooling system, makes the currently used air conditioning systems energy inefficient.A key feature of the architecture without air extraction from the main engines compressors is the use of electric drive compressors as a source of compressed air.A comparative analysis of competing variants of on-board air conditioning system without air extraction from engines for longrange aircraft projects was performed at the Moscow Aviation Institute (National Research University).The article deals with the main approaches to the decision-making process on the appearance of a promising aircraft on-board air conditioning system at the stage of its conceptual design and formulated the basic requirements for the structure of a complex criterion at different life cycle stages.The level of technical and technological risk, together with a larger installation weight, will require significant costs for development, testing, debugging and subsequent implementation, but at the same time on-board air conditioning system scheme without air extraction from the engines will achieve a significant increase in fuel efficiency at the level of the entire aircraft.

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