Ventilation Equipment Research Articles

Study on ventilation scheme and application during construction of high altitude gas tunnel

It is the key and difficult point to ensure the safety of tunnel construction by ventilation in high gas tunnel construction in high altitude and cold area. Taking ning-chan high gas tunnel as the research object, the ventilation of the tunnel is calculated, the ventilation parameters are optimized, the ventilation equipment is selected according to the calculation results, the location of the ventilation equipment is optimized, and the reasonable construction ventilation scheme is determined. The results show that through the design of the above ventilation scheme and the control of the site, it can not only ensure the ventilation demand of the super long and high gas tunnel construction in the high cold and high altitude area, but also ensure the tunnel construction in winter, and effectively save the construction ventilation cost.

Экспериментальные исследования вентиляторов типа ВКР-4 при работе в сельскохозяйственных помещениях

One of the most important factors for increasing productivity in animal husbandry, poultry farming, and in greenhouse complexes, including for growing mushrooms, is the microclimate. To ensure normal air exchange in agricultural premises, roof fans with horizontal discharge of the VKR-4 type are recommended and used. When using ventilation equipment, it is necessary to take into account the technological requirements for creating a microclimate and the capabilities of the equipment. (Research purpose) The research purpose is in justifying the rational parameters of the system for creating a microclimate in agricultural premises when using a fan of the VKR-4 type, and to give recommendations to the agricultural producer. (Materials and methods) Authors investigated the efficiency of regulating the performance of the ventilation system by means of a valve in the exhaust shaft of the ventilator and by changing the supply voltage of the electric motor. (Results and discussion) The article presents experimental studies of the operation of the ventilation system when using a roof fan of the VKR-4 type to determine its effectiveness in order to maintain the required zootechnical parameters in rooms for keeping animals at the lowest energy costs. (Conclusions) Regulating the performance of the ventilation unit by means of a mechanical flap in the exhaust shaft of the fan by changing the angle of its opening is uneconomical. The regulation by reversing the electric motor provides a 1:2 ratio of the air supply, but the power consumption of the electric motor increases almost twice during the reverse. When the fan performance is controlled by changing the motor voltage from 70 to 173 volts of line voltage, the performance increases, but with a further increase in voltage, it does not change, and the power consumption continues to increase.

Answering the Challenge of COVID-19 Pandemic Through Innovation and Ingenuity.

The novel coronavirus disease 2019 (COVID-19) pandemic has created a maelstrom of challenges affecting virtually every aspect of global healthcare system. Critical hospital capacity issues, depleted ventilator and personal protective equipment stockpiles, severely strained supply chains, profound economic slowdown, and the tremendous human cost all culminated in what is questionably one of the most profound challenges that humanity faced in decades, if not centuries. Effective global response to the current pandemic will require innovation and ingenuity. This chapter discusses various creative approaches and ideas that arose in response to COVID-19, as well as some of the most impactful future trends that emerged as a result. Among the many topics discussed herein are telemedicine, blockchain technology, artificial intelligence, stereolithography, and distance learning.

SELECTION OF TURBULENCE MODEL IN ANSYS CFX FOR INVESTIGATION OF TURBULENT NOISE AND VIBRATION OCCURRING IN INTERSCAPULAR SPACE OF THE CENTRIFUGAL TURBINE

The article is devoted to issues related to the occurrence of noise and vibration in the centrifugal turbine of ventilation equipment of residential buildings. Airflow in the rotating radial-axial channel representing a simplified configuration of the interblade channel of a centrifugal turbine is studied. Numerical simulation of the airflow in the considered geometrical domain is performed using ANSYS CFX solver. A particular attention is given to different turbulence closures used in the model. Accuracy of the simulation results was estimated with respect to the laboratory measurements by J. Moore [9]. The comparison was carried out for velocity profiles measured at three different cross-sections of the channel under different mass flow rates.

Artificial intelligence assisted false alarm detection and diagnosis system development for reducing maintenance cost of chillers at the data centre

According to a literature survey, artificial intelligence (AI)-assisted fault detection and diagnosis (FDD) for heat, ventilation, and air conditioning equipment can only reach a correct diagnosis rate of 97%–98.8% Yet, for industrial application, even 1% uncertainty may cause serious problems. Therefore, with AI-assisted FDD (AI-FDD), it is difficult to satisfy high-reliability requirements. This study proposed an innovative AI-assisted false alarm detection and diagnosis (AI-FADD) system. The proposed AI-FADD system combines signal preprocessing, a fault-free classifier, and a fault classifier to meet the requirement of Six Sigma and 3.4 defective parts per million opportunities (DPMO); the developed system achieved 14.48 DPMO, approaching the Six Sigma standard; for 1 million opportunities for alarm, the system only guaranteed 14.48 incorrect false alarm rejections. The developed system can be used for chillers at data centres, which have stringent reliability requirements. Operational data for 14 chillers distributed across north, central, and south Taiwan in 2019 indicated that chiller malfunction alarms were triggered 122 times, but the AI-FADD system determined that only 57 were actual malfunctions; the others were false alarms. According to data verification, the system reached a 100% correct rejection rate, yielding a maintenance savings of up to 260 person-hours. These substantial labour cost savings indicate that commercial application of the AI-FADD system can result in financial benefits.

Indoor air quality in new and renovated low-income apartments with mechanical ventilation and natural gas cooking in California.

This paper presents pollutant concentrations and performance data for code-required mechanical ventilation equipment in 23 low-income apartments at 4 properties constructed or renovated 2013-2017. All apartments had natural gas cooking burners. Occupants pledged to not use windows for ventilation during the study but several did. Measured airflows of range hoods and bathroom exhaust fans were lower than product specifications. Only eight apartments operationally met all ventilation code requirements. Pollutants measured over one week in each apartment included time-resolved fine particulate matter (PM2.5 ), nitrogen dioxide (NO2 ), formaldehyde and carbon dioxide (CO2 ) and time-integrated formaldehyde, NO2 and nitrogen oxides (NOX ). Compared to a recent study of California houses with code-compliant ventilation, apartments were smaller, had fewer occupants, higher densities, and higher mechanical ventilation rates. Mean PM2.5 , formaldehyde, NO2 , and CO2 were 7.7µg/m3 , 14.1, 18.8, and 741ppm in apartments; these are 4% lower, 25% lower, 165% higher, and 18% higher compared to houses with similar cooking frequency. Four apartments had weekly PM2.5 above the California annual outdoor standard of 12µg/m3 and also discrete days above the World Health Organization 24-hour guideline of 25µg/m3 . Two apartments had weekly NO2 above the California annual outdoor standard of 30ppb.

3D printing for development of medical equipment amidst coronavirus (COVID-19) pandemic—review and advancements

Background and aimsCoronavirus (COVID-19) has surfaced as a global pandemic and has created an unprecedented global demand for medical equipment. The shortage of onsite workforce, need for social distancing and less time available for sourcing have further made it difficult for the governments and the medical professionals to combat the pandemic. This study’s prime objective is to review the advancements in the area of 3D printing to develop medical equipment and explore the potential of 3D printing in addressing the shortage of medical equipment mainly the personal protective equipment (PPE) amidst COVID-19 pandemic.Methods3D printing or additive manufacturing has emerged as a new manufacturing process with tremendous potential to develop complex products in short time with minimal human interventions. The paper summarises 3D printing’s potential to serve the increasing need for medical equipment, mainly personal protective equipment (PPE) and ventilator equipment in the ongoing global COVID-19 pandemic.ResultsThe minimum human interventions required to carry out production using 3D printing also make the technology an excellent option to deal with the current situation.ConclusionsThe recommendations and opinions presented in the paper shall act as a stimulant to develop components very critical for the pandemic and help save precious lives globally.

ANALYSIS OF EQUIPMENT FAULTS IN INDOOR CLIMATE SYSTEMS AND THEIR DETECTION AND DIAGNOSIS MEASURES

Indoor climate systems required to provide indoor climate and ensure indoor air quality, failures affect the amount of energy consumed in a building, although insufficient attention is paid to their operation. The energy consumption can be reduced due to ensured proper operation of indoor climate systems avoiding equipment faults. The article reviews scientific articles, those represent typical heating, ventilation and air conditioning (HVAC) systems equipment faults of the most energy intensive office and commercial buildings. Measures of detecting and diagnosis equipment failures as well are identified. A generalized overview of the study area shows the typical faults of the indoor climate system are related to the control of the devices, sensors, deterioration of equipment performance. The most commonly used methods for detecting and diagnosing faults are automated fault detection and diagnosis (AFDD) methods. Possible solutions for troubleshooting HVAC systems are presented.

Aggregation and data driven identification of building thermal dynamic model and unmeasured disturbance

An aggregate model is a single-zone equivalent of a multi-zone building, and is useful for many purposes, including model based control of large heating, ventilation and air conditioning (HVAC) equipment. This paper deals with the problem of simultaneously identifying an aggregate thermal dynamic model and unknown disturbances from input–output data of multi-zone buildings. The unknown disturbance is a key challenge since it is not measurable but non-negligible. We first present a principled method to aggregate a multi-zone building model into a single zone model, and show the aggregation is not as trivial as it has been assumed in the prior art. We then provide a method to identify the parameters of the model and the unknown disturbance for this aggregate (single-zone) model. Finally, we test our proposed identification algorithm to data collected from a multi-zone building testbed in Oak Ridge National Laboratory. A key insight provided by the aggregation method allows us to recognize under what conditions the estimation of the disturbance signal will be necessarily poor and uncertain, even in the case of a specially designed test in which the disturbances affecting each zone are known (as the case of our experimental testbed). This insight is used to provide a heuristic that can be used to assess when the identification results are likely to have high or low accuracy.

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

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.

Обеспечение безопасных условий деятельности сотрудников по фактору вентиляция в подземных рудниках при работе техники, оснащенной двигателями внутреннего сгорания

Increasing production capacities and developing ventilation systems in underground mines challenge mining enterprises to enhance the output level of applied mining and ventilation facilities. Most of the rock loading and transporting mining machinery at ore deposits is powered by diesel internal combustion engines. Insufficient ventilation or wrong approaches to determining the amount of air required to dilute the main components of exhaust gases from internal combustion engines, including carbon monoxide and nitrogen oxides, can result in poisoning or even death of mining workers. However, most production facilities make their ventilation systems operate at the capacity limits without any opportunities to increase their technical reserves. This fact has a direct impact on safety of mining operations. We present methods and equations aimed at determining the required air quantity for the operating areas of the vehicles equipped with internal combustion engines and the underground mines at their designing and operation stages. The analysis of regulatory documentation shows that there is no requirement to airflow rate per power unit of internal combustion engines. Therefore, we propose an approach that meets up-to-date industrial safety requirements based on the actual emissions of harmful components, performance parameters of internal combustion engines and emission standards guaranteed by manufacturers though confirming an engine’s emission class compliance. The proposed methods will allow us to enhance workplace safety at underground mines where internal combustion engine equipment is on duty, and to increase the efficiency of designing new blocks, horizons and mines by eliminating unreasonable reserves when selecting mining and ventilation equipment.

A study of the source-sink system with uneven suction

Suction hoods are used on a wide-spread basis in ventilation equipment in order to capture harmful substances released by process equipment. The efficiency of such devices is dependent not only on the relative position of the source of contamination and that of the suction hood but also on suction uniformity. Where the location of the source and that of the suction hood is misaligned, the need arises to put in place an uneven velocity field in the suction hood.This papers explores the flow of hazardous substances from the “source” to the “sink” located at an angle of 180 degrees relative to each other. Collection efficiency was determined numerically by means of the Fluent software as well as experimentally. A screen was mounted inside to ensure uneven suction. The study yielded flow current lines and constant temperature lines. It also helped to define maximum suction intensity.The findings may be used for designing ventilation systems intended for industrial buildings.

Assessment of engineering equipment noise impact of agricultural enterprise on the adjacent residential building

A significant source of increased noise in cities is the engineering and technological equipment of enterprises located in immediate vicinity of standardized objects. The expected noise levels from technological and ventilation equipment of an agricultural enterprise located in the city are estimated. A computer model of the territory under consideration is built using the software package “ARM Acoustics”. As the initial data, the results of field measurements were used. The calculation of the expected noise levels near the facades of residential buildings showed the excess of regulatory levels. It is shown the necessity to install noise screens not only near equipment located on the ground, but also near equipment installed on the roof of the industrial building. The calculation was carried out taking into account the location of the U - shaped screens, which provided effective protection against noise. To illustrate the effect obtained, maps of the spatial distribution of noise are constructed.

Rare but Fatal Case of Cavitary Pneumonia Caused by Alcaligenes Faecalis

Alcaligenes faecalis is a gram-negative bacterium that is commonly found in the environment. This pathogen is usually transmitted in the form of droplets through ventilation equipment and nebulizers, but transmission through direct contact has also been documented in few case reports. This pathogen can cause rare but fatal infections including appendicitis, abscesses, meningitis, bloodstream infection, endocarditis, and post-operative endophthalmitis. Pan drug resistance to all commercially available antibiotics has been emerging globally. We present the case of a 66-year-old male who had respiratory failure along with multiple comorbidities. A large cavitary lesion caused by pan drug-resistant Alcaligenes faecalis was found on chest imaging. Despite the treatment with broad-spectrum antibiotics, the clinical outcome was very poor.

Why the lower reported prevalence of asthma in patients diagnosed with COVID-19 validates repurposing EDTA solutions to prevent and manage treat COVID-19 disease

There currently is no specific antiviral drug or a vaccine for SARS-CoV-2/COVID-19 infections; now exceeding 10,300,000 infections worldwide. In the absence of animal models to test drugs, we need to find molecular explanations for any unforeseen peculiarities in clinical data, especially the recent reports describing an unexpected asthma paradox. Asthma is considered a high medical risk factor for susceptibility to SARS-CoV-2/COVID-19 infection, yet asthma is not on the list of top 10 chronic health problems suffered by people who died from SARS-CoV-2/COVID-19. Resolving this paradox requires looking beyond the binary model of a viral receptor-binding domain (RBD) attaching to the ACE-2 receptor. A NCBI pBlast analysis revealed that the SARS-CoV-2 surface spike protein contains key two calcium-dependent fusion domains that are almost identical to those that were recently discovered SARS-CoV-1. These viral calcium-dependent binding domains can facilitate membrane fusion only after cleavage by the host surface protease TMPRSS2. Importantly, TMPRSS2 also requires calcium for its SRCR (scavenger receptor cysteine-rich) domain and itsLDLRA(LDL receptor class A) domain. Thus, the presence of EDTA excipients in nebulized β2-agonist medicines can disrupt SARS-CoV-2/COVID-19 infection and can explain the asthma paradox. This model validates repurposing EDTA in nebulizer solutions from a passive excipient to an active drug for treating COVID-19 infections. Repurposed EDTA delivery to respiratory tissues at an initial target dose of 2.4 mg per aerosol treatment is readily achievable with standard nebulizer and mechanical ventilator equipment. EDTA warrants further investigation as a potential treatment for SARS-CoV-2/COVID-19 in consideration of the new calcium requirements for virus infection and the regular presence of EDTA excipients in common asthma medications such as Metaproterenol. Finally, the natural history of Coronavirus diseases and further analysis of the fusion loop homologies between the Betacorona SARS-CoV-2 virus and the less pathogenic Alphacorona HC0V-229E virus suggest how to engineer a hybrid virus suitable for an attenuated alpha-beta SARS-CoV-2/COVID-19 vaccine. Thus, replacing SARS-CoV-2 fusion loops (amino acids 816–855) with the less pathogenic HCoV-229E fusion loop (amino acids 923–982) may provide antigenicity of COVID-19, but limit the pathogenicity to the level of HCoV-229E.

Theoretical and Experimental Investigation on Different Parameters Affecting Heat Pipe Performance Charged with R-22

The present work was carried out theoretically and experimentally to study the performance enhancement of the heat pipe charged with refrigerant (R-22) as a working fluid. The heat pipe heat exchangers are used in heat recovery applications to cool the incoming fresh air in air conditioning systems. The study discusses the effect of inclination angle and supply on temperature on thermal efficiency, supply off temperature (T2), thermal resistance and heat recovered of the heat pipe heat exchanger. Two streams of fresh and return air have been flowed through the heat pipe heat exchanger to investigate the performance of heat recovery system. The heat pipe heat exchanger is consisting of one row of 16 copper tubes and aluminum fins. The diameter of each copper tube is 9.53 mm. The experiments were performed due to ASHRAE standard 1060(I-P) for performance rating of air-to-air exchangers for energy recovery ventilation equipment [1]. The results showed that Heat pipe efficiency and heat recovered capacity are increased by increasing the inclination angle until reach its maximum values at (θ=30o) and then decreased with further increase in inclination angle. The results showed also that the thermal efficiency and heat-recovered capacity are increased by increasing the supply on temperature

Дослідження оптимального розміщення витяжного вентиляційного обладнання в пташнику за допомогою чисельного моделювання

Keeping poultry in damp and cold rooms with poor ventilation system reduces the weight gain of the bird, reduces its egg production and increases the incidence of young animals, as well as excessive feed consumption and exceeding the growing period established by technical regulations. The aim of the study was to determine the effective placement of exhaust ventilation equipment at the height of the end wall of the poultry house to improve the ventilation system, reduce stagnant air zones and improve the microclimate. The numerical modeling of hydrodynamics, heat and mass transfer processes during air ventilation in poultry buildings is carried out. The analysis of the conditions of heat and mass transfer in the poultry house, depending on the placement of fans along the height of the house, and the efficiency of the location of such equipment was determined. The system for maintaining the microclimate in poultry houses was considered in the presence of a system for cooling the outside air with water from an underground well. The ventilation system uses exhaust ventilation equipment with a fan wheel diameter of 1.25 m. In the simulation, the fans were installed at a height of 1.125, 1.5 and 1.875 m from the floor to the center of the fan axis. Simulation was performed for 2D CFD models using ANSYS Fluent software. The results of CFD analysis of the air flow pattern and the thermal state inside the house are presented. As a result of numerous studies, the geometry of the location of the ventilation equipment has been found. It is shown that it is advisable to install ventilation equipment at a height of 1.5 m. At the same time, the size of stagnant zones and the uneven distribution of air velocity near the bird are reduced. Numerical modeling was carried out in order to minimize the size of stagnant zones, equalize the air flow and improve the temperature indicators in the poultry house.

ANALYSIS OF EFFICIENCY OF METHODS DRYING OF THE METRO POLYETH AIR WITH THE EQUIPMENT IN THE BYPASS WAY

Ensuring the normalized parameters of the microclimate of tunnel air of service connecting branches (SCB) of the deep underground utility company “Kiev Metro” with a length of 1400 m is a priority, through avoiding damage to the insulating materials of the contact flights, which can cause a short circuit. The location of ventilation equipment or drainage or heating installations in a single-track tunnel of the connecting branch is impossible due to limited space, therefore the only place where such equipment can be located is a bypass tunnel. With the optimized operation of the mechanical tunnel ventilation system in energy-saving modes, in 2019, for technical reasons, the soil layer around the tunnels was cooled, resulting in a decrease in the temperature of the tunnel air and an increase in relative humidity above the normal level, which sometimes reached 95 %.The value of the relative humidity of the tunnel air in underground tunnels of deep underground utility company “Kiev Metro” depends on the temperature and absolute humidity of the tunnel air, the temperature of the rim of the walls of the tunnels and the presence of possible additional sources of moisture in the tunnels.The decrease in the relative humidity of the tunnel air during the implementation of the assimilation method by increasing the air exchange SCB-1 in the line to the station. m. Khreschatyk with a length of 1400 m due to the installation of an additional ventilation unit in the bypass tunnel (in the area of PK09 + 40) and means of directing the air flow into the tunnel can lead to an increase in the flow rate of tunnel air to 30 and 26 kg/s, respectively, while the relative humidity will decrease by 5 %. To implement this method, it is necessary to expend an electric power of 40 kW.When implementing the method of drying tunnel air with an additional air drying machine located in the bypass tunnel, it is possible to reduce the relative humidity by (12...14) % and to ensure compliance with the standard humidity of 75 %. However, the implementation of this method is energy-intensive in comparison with the implementation of the assimilation method (increase in air exchange), since the necessary expenditure of electric power for drainage is about 212 kW.According to the results of the study for utility company “Kiev Metro”, a method of heating tunnel air with an additional heat gun installed in the bypass tunnel with a 40 kW heater based on electric heating elements is recommended, which will lead to heating of the tunnel air with a simultaneous decrease in relative humidity by (7...11) % warming the soil layer around the tunnel and avoiding its cooling in the future. The practical implementation of the method for heating tunnel air requires an electric power cost of about 60 kW.

Care for patients with ventricular assist devices and suspected COVID-19 infection.

Care for patients with ventricular assist devices and suspected COVID-19 infection.

Phase equilibrium and diffusivities of hydrofluorocarbons in a synthetic polyol ester lubricant

AbstractDetailed knowledge about the thermophysical properties of refrigerant/lubricant systems, such as solubility and diffusivity, are required for the design, operation, and long‐term reliability of heating, ventilation, air‐conditioning, and refrigeration equipment. Herein, vapor–liquid equilibrium of hydrofluorocarbons (HFCs) 1,1,1,2‐tetrafluoroethane (R‐134a), pentafluoroethane (R‐125), and difluoromethane (R‐32) in a polyol ester oil (ISO VG 32) were measured using a gravimetric microbalance at temperatures ranging from 248.15 to 348.15 K and up to 1.0 MPa of pressure. The experimental solubility data of each refrigerant/lubricant system were successfully modeled using the nonrandom two liquid activity coefficient model. A one‐dimensional diffusion equation was applied on time‐dependent absorption data to determine binary diffusion coefficients (D) for the refrigerants in the ISO VG 32 lubricant. Finally, Stokes–Einstein diffusing radius calculations support the hypothesis that HFCs dissolve into ISO VG 32 lubricant as individual molecules rather than associated complexes.