scholarly journals Impact of Negative Pressure in a Room Due to Increased Airtightness in Residential Apartment Housing

2019 ◽  
Vol 111 ◽  
pp. 01094
Author(s):  
Yoshihiro Toriumi ◽  
Takashi Kurabuchi
Keyword(s):  
Negative Pressure ◽  
Ventilation System ◽  
Air Conditioner ◽  
Drain Pipe ◽  
Multiple Factors ◽  
Air Intake ◽  
The Impact

This study surveyed the impact of a negative pressure in a room in a highly airtight residential apartment with Class 3 ventilation (natural air intake and mechanical exhaust). The results of the study are as follows. 1) A room may reach an excessive level of negative pressure depending on how the ventilation system is used. 2) Noise from the drain pipe of a room air conditioner caused by negative pressure in the room is dependent on how the drain pipe is installed. 3) An experiment was conducted to investigate the mechanism of a seal break in a toilet trap. However, the seal did not break. Thus, seal breaks may be caused by multiple factors.

Impact of Switching Time Interval for Dual Intakes on Workers in Main Control Room During Accidents

2017 ◽  
Author(s):  
Xue Na ◽  
Lin Hongtao ◽  
Liu Xinjian ◽  
Mao Yawei ◽  
Qiu Lin
Keyword(s):  
Switching Time ◽  
Ventilation System ◽  
The Other ◽  
Time Interval ◽  
Control Room ◽  
Relief Valve ◽  
Frequent Switching ◽  
Air Intake ◽  
Switching Action ◽  
The Impact

The main control room (MCR) ventilation system has been designed to maintain habitability of the control room envelope both under normal condition and accident condition. The system adopting dual air intakes adds one more air intake for accidents at suitable position. During accidents, the air intake with lower contamination will be selected and the other with higher contamination will be isolated, to reduce the amount of radioactive substances entering MCR extremely and enhance the habitability of MCR envelop. This paper is devoted to research on the impact of switching time interval (STI) for dual intakes on workers in main control room during accidents. As the contamination condition varies, the switching action will be happened. Switching time interval (STI) referred in this paper means the time between two switching actions. When accidents occur, the air intake will operate and switch between two intakes automatically. The action of switching will be influenced by several parameters: the meteorological conditions of the site, the response features of the monitoring instruments and the source term released to the environment after accidents. Analysis of these parameters and their sensitivity analysis are performed, which show that the ventilation system cannot afford too frequent switching actions resulted from instantaneous sudden changes of intake’s activity. That’s the reason why it is necessary to set a minimum STI which means the contamination of one intake have to be lower than the other intake and this dominant position should be kept longer than the minimum STI, if not, the switching action will not be happened. As it is essential to set a minimum STI to prevent frequent switching of system, the analysis of its impact on the atmospheric relative concentrations and the doses of the workers in main control room are performed on basis of specific site meteorological condition and the response characteristic of dose monitoring instruments. Three kinds of accident release conditions are considered, which are relief valve release, containment leakage and elevated funnel release. The atmospheric relative concentrations and the doses of the workers in MCR are evaluated for every case and compared with the dose limits. Finally an acceptable minimum STI of dual air intakes is recommended.

Numerical and Experimental Modeling of Indoor Air Quality Inside a Conditioned Space with Mechanical Ventilation and DX-Air Conditioner

2020 ◽  
Vol 38 (9A) ◽  
pp. 1257-1275
Author(s):  
Wisam M. Mareed ◽  
Hasanen M. Hussen
Keyword(s):  
Air Quality ◽  
Indoor Air Quality ◽  
Indoor Air ◽  
Ventilation System ◽  
Thermal Conditions ◽  
Airflow Rate ◽  
Air Conditioner ◽  
Breathing Zone ◽  
Lecture Room ◽  
Ventilation Performance

 Elevated CO2 rates in a building affect the health of the occupant. This paper deals with an experimental and numerical analysis conducted in a full-scale test room located in the Department of Mechanical Engineering at the University of Technology. The experiments and CFD were conducted for analyzing ventilation performance. It is a study on the effect of the discharge airflow rate of the ceiling type air-conditioner on ventilation performance in the lecture room with the mixing ventilation. Most obtained findings show that database and questionnaires analyzed prefer heights between 0.2 m to 1.2 m in the middle of an occupied zone and breathing zone height of between 0.75 m to 1.8 given in the literature surveyed. It is noticed the mismatch of internal conditions with thermal comfort, and indoor air quality recommended by [ASHRAE Standard 62, ANSI / ASHRAE Standard 55-2010]. CFD simulations have been carried to provide insights on the indoor air quality and comfort conditions throughout the classroom. Particle concentrations, thermal conditions, and modified ventilation system solutions are reported.

scholarly journals Biogas Dry Reforming for Hydrogen through Membrane Reactor Utilizing Negative Pressure

Fuels ◽  
2021 ◽  
Vol 2 (2) ◽  
pp. 194-209
Author(s):  
Akira Nishimura ◽  
Tomohiro Takada ◽  
Satoshi Ohata ◽  
Mohan Lal Kolhe
Keyword(s):  
Energy Source ◽  
Reaction Temperature ◽  
Negative Pressure ◽  
Membrane Reactor ◽  
Reaction Chamber ◽  
Dry Reforming ◽  
Molar Ratio ◽  
Effect Of Pressure ◽  
The Impact

Biogas, consisting of CH4 and CO2, is a promising energy source and can be converted into H2 by a dry reforming reaction. In this study, a membrane reactor is adopted to promote the performance of biogas dry reforming. The aim of this study is to investigate the effect of pressure of sweep gas on a biogas dry reforming to get H2. The effect of molar ratio of supplied CH4:CO2 and reaction temperature is also investigated. It is observed that the impact of psweep on concentrations of CH4 and CO2 is small irrespective of reaction temperature. The concentrations of H2 and CO increase with an increase in reaction temperature t. The concentration of H2, at the outlet of the reaction chamber, reduces with a decrease in psweep. It is due to an increase in H2 extraction from the reaction chamber to the sweep chamber. The highest concentration of H2 is obtained in the case of the molar ratio of CH4:CO2 = 1:1. The concentration of CO is the highest in the case of the molar ratio of CH4:CO2 = 1.5:1. The highest sweep effect is obtained at reaction temperature of 500 °C and psweep of 0.045 MPa.

The Impact of Negative-Pressure Wound Therapy with Instillation Compared with Standard Negative-Pressure Wound Therapy

2014 ◽  
Vol 133 (3) ◽  
pp. 709-716 ◽  
Author(s):  
Paul J. Kim ◽  
Christopher E. Attinger ◽  
John S. Steinberg ◽  
Karen K. Evans ◽  
Kelly A. Powers ◽  
...  
Keyword(s):  
Negative Pressure ◽  
Negative Pressure Wound Therapy ◽  
Wound Therapy ◽  
The Impact

The impact of menopausal status on cardiac responses to exercise training and lower body negative pressure

Maturitas ◽  
2017 ◽  
Vol 103 ◽  
pp. 91
Author(s):  
Amanda Q.X. Nio ◽  
Eric J. Stöhr ◽  
Samantha Rogers ◽  
Rachel Mynors-Wallis ◽  
Jane M. Black ◽  
...  
Keyword(s):  
Exercise Training ◽  
Negative Pressure ◽  
Lower Body Negative Pressure ◽  
Menopausal Status ◽  
Lower Body ◽  
Cardiac Responses ◽  
The Impact

scholarly journals Quality of outdoor and indoor environment during the cruise of the tall ship STS Fryderyk Chopin

2018 ◽  
Vol 49 ◽  
pp. 00024
Author(s):  
Szymon Firląg
Keyword(s):  
Relative Humidity ◽  
Ventilation System ◽  
Pm 2.5 ◽  
The North ◽  
University Of Technology ◽  
Open Sea ◽  
The North Sea ◽  
Pm 10 ◽  
The Impact

The aim of this paper is to present the results of measurements, on the quality of internal and external environment, carried out during the cruise of the tall ship STS Fryderyk Chopin. The cruise took place between 16th and 30th September 2017 as part of the scientific seminar of the Warsaw University of Technology (WUT) on the Wave, addressed to students of the WTU. After leaving the port of Edinburgh, crossing the North Sea, the Danish straits, stops in Copenhagen and Kołobrzeg, the tall ship reached Szczecin after two weeks. The measurements carried out on the deck included the temperature and relative humidity of the indoor air in three cabins and the men’s bathroom. In two cabins, the CO2 concentration was measured additionally. The outdoor temperature, relative humidity and concentration of PM 1.0, PM 2.5 and PM 10 were also measured. The obtained results allowed to assess the quality of the internal environment in accordance with the standards and to analyze the effectiveness of the mechanical ventilation system. Measurements of particulate matter have shown significant differences between outdoor air quality in the open sea and in ports or near major shipping routes. It turned out that the impact of emissions from passing ships using diesel engines is clearly visible.

Odor Monitoring and Mitigation at the Hennepin County Waste to Energy Facility

2007 ◽  
Author(s):  
Jake Smith
Keyword(s):  
Negative Pressure ◽  
Waste To Energy ◽  
The North ◽  
Energy Facility ◽  
Hennepin County ◽  
Parking Lot ◽  
Baseline Information ◽  
Odor Monitoring ◽  
Baseball Team ◽  
The Impact

Hennepin Energy Recovery Center (HERC) is a waste to energy facility owned by Hennepin County and operated by Covanta Energy. HERC has been in operation since 1989. The facility burns 365,000 tons of residential and commercial solid waste per year and generates about 34 mega-watts of electricity that is sold to Xcel Energy. HERC is located on the north side of downtown Minneapolis in the Historic Warehouse District, a neighborhood that is changing from industrial to a more commercial/residential mix with loft conversions and construction of new condominiums. The Minnesota Twins baseball team is also siting a new stadium in the parking lot immediately southeast of the facility. The potential for odors from the tipping floor of the facility affecting the neighborhood has become more of a concern due to the changes in the neighborhood. In March 2004 the County began an odor study. This included developing baseline information on odors from HERC and from the surrounding community by conducting daily odor monitoring at select points on the facility property and throughout the community: • Determining how far odors from HERC migrate into the community. • Quantifying detected odors using a Nasal Ranger. • Determining the factors that contribute to these odors. • Developing a method of controlling these odors. • Continued monitoring to determine the impact of mitigation methods. Odors detected were characterized as garbage odors, garbage-related odors, and neighborhood odors. Baseline data showed that while garbage odors from HERC were mostly undetectable beyond the perimeter of the property, there was room for improvement in decreasing the presence and intensity of these odors. The tipping hall was designed to operate under negative pressure to control odors, however the entrance and exit doors were always open and a negative pressure could not be maintained.

scholarly journals Use of Closed Incision Negative Pressure Therapy (ciNPT) in Breast Reconstruction Abdominal Free Flap Donor Sites

2021 ◽  
Vol 10 (21) ◽  
pp. 5176
Author(s):  
Jennifer Wang ◽  
Zyg Chapman ◽  
Emma Cole ◽  
Satomi Koide ◽  
Eldon Mah ◽  
...  
Keyword(s):  
Breast Reconstruction ◽  
Free Flap ◽  
Negative Pressure ◽  
Statistical Significance ◽  
Future Research ◽  
Wound Complications ◽  
Negative Pressure Therapy ◽  
Royal Melbourne Hospital ◽  
Pressure Therapy ◽  
The Impact

Background: Closed incision negative pressure therapy (ciNPT) may reduce the rate of wound complications and promote healing of the incisional site. We report our experience with this dressing in breast reconstruction patients with abdominal free flap donor sites. Methods: A retrospective cohort study was conducted of all patients who underwent breast reconstruction using abdominal free flaps (DIEP, MS-TRAM) at a single institution (Royal Melbourne Hospital, Victoria) between 2016 and 2021. Results: 126 female patients (mean age: 50 ± 10 years) were analysed, with 41 and 85 patients in the ciNPT (Prevena) and non-ciNPT (Comfeel) groups, respectively. There were reduced wound complications in almost all outcomes measured in the ciNPT group compared with the non-ciNPT group; however, none reached statistical significance. The ciNPT group demonstrated a lower prevalence of surgical site infections (9.8% vs. 11.8%), wound dehiscence (4.9% vs. 12.9%), wound necrosis (0% vs. 2.4%), and major complication requiring readmission (2.4% vs. 7.1%). Conclusion: The use of ciNPT for abdominal donor sites in breast reconstruction patients with risk factors for poor wound healing may reduce wound complications compared with standard adhesive dressings; however, large scale, randomised controlled trials are needed to confirm these observations. Investigation of the impact of ciNPT patients in comparison with conventional dressings, in cohorts with equivocal risk profiles, remains a focus for future research.

scholarly journals Assessment of Building Automation and Control Systems in Danish Healthcare Facilities in the COVID-19 Era

2022 ◽  
Vol 12 (1) ◽  
pp. 427
Author(s):  
Jeanette Maria Pedersen ◽  
Farah Jebaei ◽  
Muhyiddine Jradi
Keyword(s):  
Air Quality ◽  
Ventilation System ◽  
Hot Water ◽  
Building Automation ◽  
Efficient Operation ◽  
Healthcare Facilities ◽  
Automation And Control ◽  
And Control ◽  
Indoor Conditions ◽  
The Impact

A well-designed and properly operated building automation and control system (BACS) is key to attaining energy-efficient operation and optimal indoor conditions. In this study, three healthcare facilities of a different type, age, and use are considered as case studies to investigate the functionalities of BACS in providing optimal air quality and thermal comfort. IBACSA, the first-of-its-kind instrument for BACS assessment and smartness evaluation, is used to evaluate the current systems and their control functionalities. The BACS assessment is reported and analyzed. Then, three packages of improvements were implemented in the three cases, focusing on (1) technical systems enhancement, (2) indoor air quality and comfort, and (3) energy efficiency. It was found that the ventilation system domain is the best performer in the three considered cases with an overall score of 52%, 89% and 91% in Case A, B, and C,, respectively. On the other hand, domestic hot water domain scores are relatively low, indicating that this is an area where Danish healthcare facilities need to provide more concentration on. A key finding indicated by the assessment performed is that the three buildings score relatively very low when it comes to the impact criteria of energy flexibility and storage.

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