Fan Operation Research Articles

Dynamics of airborne particulate matter and fungi after short-time operation of an air purifier fan: a preliminary evaluation at a special elderly nursing home as a model of living environment

Dynamics of airborne particulate matter and fungi after short-time operation of an air purifier fan: a preliminary evaluation at a special elderly nursing home as a model of living environment

Prediction of Parts Temperature in Cooling Fan Operating State after Key-off

Prediction of Parts Temperature in Cooling Fan Operating State after Key-off

Researches on the Determination of the Minimum Driving Power of a Fan Operating at a Suction Hood

Researches on the Determination of the Minimum Driving Power of a Fan Operating at a Suction Hood

Research on Adaptive Iterative Learning Control of Air Pressure in Railway Tunnel With IOTs Data

When a train enters a tunnel, the passengers in the train will feel tinnitus. The main reason is that the pressure in the tunnel enters the vehicle through the adjusting system of the train, which will cause discomfort to the passengers. In this paper, according to the quasi-periodicity and repeatability of mass data in the process of train running in tunnels, a control method based on the IOTs big data is proposed, and an adaptive iterative learning control algorithm based on the IOTs big data is established. The fan operation frequency of ventilation system is regulated by adaptive iterative learning control algorithm, and can adjust the new air and exhaust gas of the ventilation system in real time to restrain the pressure fluctuation in the train. Finally, the simulation results show that the adaptive iterative learning control algorithm based on the Internet of Things can significantly reduce the amplitude of pressure fluctuation in the tunnel and the change rate of the ventilator, and improve the passenger comfort program. Moreover, the real-time measured data also show that the proposed closed-loop adaptive iterative learning control algorithm based on the Internet of Things is obviously superior to active control.

Developing Guidelines for Thermal Comfort and Energy Saving during Hot Season of Multipurpose Senior Centers in Thailand

In Thailand, many government buildings and facilities are adapted to serve as Multipurpose Senior Centers (MSCs). However, most of them have been used without taking into account of thermal comfort of occupants. The present research aimed to develop guidelines for improving suitable indoor environment for the Thai elderly in hot season and analyze energy use of the 3 case-study MSCs. Both field study and climate-controlled chamber study were conducted. The obtained data were analyzed to develop the equation for predicting the thermal sensation, which would be inputted in the scSTREAM program for analysis purposes. The energy use was evaluated using the DOE-2 program. The results suggested that during 8:00 a.m.–12:00 p.m., natural ventilation should be used together with orbit fans to produce an actual air velocity of 0.64–0.73 m/s. From 12:00 p.m. to 4:00 p.m., air conditioners should set at 26.00–26.50 °C with an actual air velocity of 0.06–0.22 m/s. The results also showed that the developed guidelines could improve the level of thermal comfort from “slightly cool” to “neutral” and reduce energy use in hot season by 16.56% due to the reduction of cooling load and fan operation of air conditioning systems. Moreover, energy consumption in MSCs are also affected by the building parameters. These findings can be applied as guidelines for improving a large number of MSCs in Thailand.

Ammonia emission from a manure-belt laying hen facility equipped with an external manure drying tunnel

Ammonia is the main pollutant associated to laying hen facilities. Best Available Techniques such as manure drying tunnels have been implemented to minimise ammonia losses. However, scarce information is available about their performance as a cleaner technology. Ammonia emission from a manure-belt laying hen building and the annexed external manure drying tunnel were measured from July 2015 to October 2016 under Continental Mediterranean climate conditions. Ammonia emission from the building and manure drying tunnel were continuously measured by a photoacoustic multi gas analyser. Temperature and relative humidity were monitored. The uncertainty of ammonia emission calculation was examined. Nitrogen mass balance was also used to estimate ammonia losses from the building. Results showed that the annual mean ammonia emission from the building was 93.8 mg ammonia d−1 hen−1. Mean ammonia emission uncertainty in the building was 9.7% throughout the sampling period. Ventilation rate was identified as the main factor affecting uncertainty due to the variability of fans operation. Concerning the manure drying tunnel, mean ammonia emission was 209.3 mg NH3 d−1 hen−1. Ammonia losses were affected by the atmospheric temperature and relative humidity, and manure dry matter content in both systems. Manure ammonia emission should be researched in following steps of the manure continuum to state the manure drying tunnel as a cleaner production technology. Ammonia emission estimation by nitrogen mass balance method was 98.4 mg NH3 d−1 hen−1. It was demonstrated to be a good indicator of the ammonia emission over the year although it did not reflect the variations between shorter time periods.

A method for extracting performance metrics using work-order data

Holistic performance metrics are necessary to understand how operational resources are used and to detect anomalous zones, floors, equipment, and work-order categories in large commercial and institutional buildings. Work-order data in computerized maintenance management systems (CMMS) represent an untapped potential to extract such performance metrics. In this paper, a method to conduct text analytics on CMMS data is developed and demonstrated through a case study in which four years’ worth of data from four large commercial buildings are used. Association rule mining technique is employed to identify building, system, and component-level recurring work-order taxonomies and common failure modes. The results highlight the potential of kernel density functions, decision trees, Sankey diagrams, survival curves and stacked line plots to effectively visualize the temporal, spatial, and categorical anomalies in the complaint patterns. It is identified that often only a few floors and complaint types account for most of the complaints in a building. The analysis of operator comments reveal that the most frequent lighting-related complaints are resolved by replacing ballasts and lights, and the thermal and air quality complaints are addressed by adjusting the temperature setpoints, airflow rates, and fan operation schedules.

Airflow pattern induced by ceiling fan under different rotation speeds and blowing directions

Ceiling fans have been widely used as effective cooling and air mixing method for building environment conditioning. Understanding its airflow characteristics can be helpful to utilize ceiling fan or integrate it with background air conditioning system. However, the airflow induced by ceiling fan has different flow patterns under different rotating speeds and blowing directions. To date, it is still challenging to capture those complicated airflow fields in room scale. In this study, the airflow pattern induced by a ceiling fan was measured with a new technology, quad-view colour sequence particle streak velocimetry. A series of isothermal experiments were conducted under five rotation speed levels with downward and upward blowing directions in a room-size (4 m × 2.5 m × 3 m) chamber. Based on comprehensive three-dimensional three-component vector measurement results, the average velocity, turbulence intensity and vorticity on the middle section were calculated and used to analyse airflow patterns induced by ceiling fan. The results show that the blowing direction of the fan determines the indoor airflow pattern. When blowing downward, the flow will cause high diversion between jet core under the fan blades and surrounding region. While for upward blowing, the air speed in lower part of the room is much lower but pretty uniform. The detailed measured airflow fields can serve as reference for ceiling fan design and operation.

Reducing human exposure to PM2.5 generated while cooking typical Chinese cuisine

Residential Chinese cooking can lead to severe exposure to carcinogenic fine particles (PM2.5) from cooking-oil fumes. Keeping the kitchen door open is conducive to improving air quality in the kitchen, but it can result in further diffusion of PM2.5 emissions into adjacent rooms. In this study, PM2.5 exposure concentrations were measured in the kitchen and an adjacent room during and after cooking activities, where various interventions were employed based on an orthogonal design. Intervention strategies, including range-hood operations, protective respirator use, personal portable fan operation, side panels configured for the range hood, and air cleaner use, were incorporated. The results demonstrated that using the range hood with an equivalent air exchange rate of 7.5–10.9 h−1 in the kitchen and wearing respirators during cooking were the most efficient prevention measures, significantly decreasing the inhalation exposure to PM2.5 for the cook in the kitchen by 90–95% and 79–84%, respectively. The average concentrations in the adjacent living room could be decreased by 50%–75% with an additional period of 5–10 min running the range hood or the air cleaner (the cleaner air exchange rate was no more than 5 h−1).

Effects of climate change on the aeration of stored beans in Minas Gerais State, Brazil

The beneficial effects of the aeration of stored grains and legumes with ambient air can be affected by changes in climate causing disorders in air temperature and relative humidity that directly affect the control strategies. The impacts of the climate change on the bean aeration in 11 mesoregions of Minas Gerais State (Brazil) were evaluated. For this, 132 simulation scenarios were analysed, including simulations of three bean harvests using measured climatic conditions, and three possible projections, representing low, intermediate and high radiative forcing levels. Based on the simulation profiles, total aeration time, grain cooling, and electrical energy consumption during bean aeration were calculated. Results were strongly affected by the weather patterns of each mesoregion and by the harvest periods of the crop. Projected climate changes tended to reduce the cooling potential, while increasing fan operation time and electrical energy requirement when aerating common beans in Minas Gerais State. The Jequitinhonha and Mucuri valleys and the North and Northwest mesoregions were predicted as no longer having suitable aeration potential since they were the most impacted by climate changes. Chilling aeration is recommended when aerating bean in these mesoregions even with the present climate and this must be intensified when considering the climate changes. In the other mesoregions, aeration with ambient air is currently suitable and this can remain viable even with the projected climate changes, but this is with the proviso that good storage practices are followed and efficient control strategies are applied.

Experimental study on ventilation and energy saving of underground buildings based on shallow ground temperature

Shallow rock and soil have a heat transfer temperature difference with the external environment, which can affect the external temperature through natural ventilation. In order to study and research the ventilation and energy saving of underground buildings based on this point, this study uses natural ventilation, field measurement, and DeST numerical simulation method to test the actual natural supply air rate of Zhengzhou metro station and the temperature, humidity, and CO2 concentration in the station. After further simulation analysis, the energy-saving design method and operation mode that make full use of natural ventilation are proposed in the end, and the energy-saving advantages that natural ventilation can bring are further explored. The results show that during the ventilation season, increasing the natural ventilation in March, April, and November can improve the thermal environment in the station and reduce the opening time of draught fan, saving the energy consumption of the fan operation, while in the months when the outdoor temperature is lower, such as in January, February, and in December, maintaining the existing natural ventilation is able to meet the station temperature requirements. It can be seen that the design of this study is reasonable and has achieved the expected effect. It can use the effect of natural ventilation on the metro station to achieve energy saving.

The trace of airborne particulate matter from smoking e-cigarette, tobacco heating system, conventional and hand-rolled cigarettes in a residential environment

Indoor particle number concentrations and size distributions were monitored in a typical, residential living room, considering two independent variables: smoking activities (using e-cigarettes, tobacco heating systems (THS), conventional and hand-rolled cigarettes) and the operation of the air conditioning (AC) system. Each smoking device exhibited its own characteristic size distribution (its own “trace”), in the room atmosphere, which was also affected by the AC operation. All devices emitted ultrafine and fine particles especially in the range around 100 nm. The minimum average PM number or mass concentrations in any size were observed for the THS (either with the AC on or off). The PM1 number concentrations were maximum when conventional cigarettes were smoked, especially when the AC was off. In the case of the coarse particles, the PM(1–10) number concentrations were maximum when hand-rolled cigarettes were smoked (and AC was on). When the AC was off, the maximum PM(1–10) number concentration was recorded when the e-cigarette was used. The effect of the AC on particle number concentrations depended on their size and their origin. A factorial ANOVA corroborated that the two independent variables affected significantly (at p < 0.05) the airborne PM number concentrations. Specifically, low versus high air temperature, fan operation or not, affected differently particles in different size ranges and for different smoking activities.

Fault Diagnosis of Mine Fan Bearing Based on Beetle Antennae Search

Mine fan is the lifeblood of coal mine safety production, which plays an important role in ensuring the safety of the lives of mine workers. Once it fails to operate, it will cause irreparable serious consequences. Therefore, in order to ensure the safe operation of mine fan, this paper takes the common motor bearing faults in fan faults as the object of study, proposes a method of using rough set attribute reduction combined with Beetle antennae search to optimize BP neural network to establish diagnosis model, and compares it with genetic algorithm, particle swarm optimization, imperial competition algorithm and ant lion optimization algorithm. The experimental results show that the method achieves 90% accuracy in fault diagnosis of mine fan bearing, and has faster convergence speed and shorter operation time. Compared with other optimization algorithms, the method has greater advantages. After many tests, the diagnosis results are stable, which proves that the method is feasible and effective in fault diagnosis of mine fan.

Energy Conservation Technique for Air Conditioner and Fan in Residential Applications

The air conditioner system plays a very essential role in our everyday lives. But air condition systems consume a lot of power. In this project, fan and AC are clubbed together and will work at different interval of time. This project is based on time variant i.e. if we set the delay time of say(1 hour) the AC will operate for 1 hour while the Fan is OFF and after 1 hour the AC will turn OFF and the Fan will operate and this operation will keep on repeating till the supply is turn OFF. The delay time for the operation of AC and Fan can be set according to our requirement through the program given to the arduino Different case studies was discussed for different Air conditioner companies for different capacities and their energy saving was analyzed for different cases.

Fan Flow Field in an Installed Variable Pitch Fan Operating in Reverse Thrust for a Range of Aircraft Landing Speeds

Abstract The installed flow field for a variable pitch fan (VPF) operating in reverse thrust for the complete aircraft landing run is described in this paper. To do this, a VPF design to generate reverse thrust by reversing airflow direction is developed for a representative 40,000 lbf modern high bypass ratio engine. Thereafter, to represent the actual flow conditions that the VPF would face, an engine model that includes the nacelle, core inlet splitter, outlet guide vanes, bypass nozzle, core exhaust duct, aft-body plug, and core nozzle is designed. The engine model with the VPF is attached to a representative airframe in landing configuration to include the effects of installation. A rolling ground plane that mimics the runway during the landing run is also included to complete the model definition. Three-dimensional (3D) Reynolds-averaged Navier–Stokes (RANS) solutions are carried out for two different VPF stagger angle settings and rotational speeds to obtain the fan flow field. The dynamic installed VPF flow field is characterized by the interaction of the freestream and the reverse stream flows. The two streams meet in a shear layer in the fan passages and get deflected radially outward before turning back onto themselves. The flow field changes with stagger setting, fan rotational speed, and the aircraft landing speed because of the consequent changes in the momentum of the two streams. The description of the installed VPF flow field as generated in this study is necessary to (a) qualify VPF designs that are typically designed by considering only the uninstalled static flow field and (b) choose the VPF operating setting for different stages of the aircraft landing run.

Characterization of volatile carbonyl compounds in defective green coffee beans using a fan assisted extraction process

In this work, the characterization of volatile carbonyl compounds profiles in healthy and defective green coffee beans was performed. The objective of this characterization was to identify carbonyl marker compounds related to the main bean defects of both arabica and robusta species (black, sour, immature and bored) in non-aged and aged beans. A simple and innovative procedure for volatile compounds extraction was developed, so that usual heating procedures that may adulterate samples' identity can be avoided. The coffee sample and an acceptor solution containing a carbonyl derivatizing reagent are placed inside a screw-cap flask featuring an inner electric fan. The efficiency of the volatile carbonyl compounds mass transfer could be increased due to the fan's operation. The experimental parameters, fan rotation speed, extraction period and sample mass were studied to improve the volatile compounds extraction before HPLC analysis. Defective green beans showed higher contents of some volatile carbonyl compounds than healthy green beans. The volatile carbonyl compounds profile obtained during the forced ageing assay revealed that butanal, benzaldehyde, 3-methylbutanal and hexanal were, consistently, found in higher amounts in both arabica and robusta defective beans, in comparison with healthy beans of the same lot.

Effect of sensor position on the performance of CO2-based demand controlled ventilation

CO2-based demand controlled ventilation (DCV) can save energy while maintaining acceptable indoor air quality. CO2 concentration may vary within an occupied space and it is unclear how sensor location influences the ventilation and energy performances. The objective of the present study is to investigate the effect of CO2 sensor position on the performance of DCV systems under mixing and displacement ventilation. Experimentally validated computational fluid dynamics (CFD) models were simulated under representative indoor ventilation and occupancy conditions. The results show that the ventilation strategy, occupancy level, and air change rate have notable impacts on the CO2 sensing performance. Under mixing ventilation, CO2 sensors placed at the room exhaust can meet the requirements of sensor accuracy defined by ASTM E741 and California Title 24. However, the sensor errors associated with sensor location can be higher than the acceptable threshold under displacement ventilation, which exhibits vertical CO2 stratification with two separated zones (lower transition zone and upper uniform zone). The dividing height of the two zones is highly sensitive to the occupancy level. In such cases, exhaust sensors can overestimate the breathing zone concentration and result in additional energy consumptions for thermal conditioning as well as fan operation, especially for densely occupied buildings. The study findings suggest that for ensuring good performance of CO2-based displacement ventilation, it is necessary to develop quantitative relationships between CO2 concentrations at the breathing height and the room exhaust considering ventilation strategies.

Analysis of the effect of seasonal climate changes on cooling tower efficiency, and strategies for reducing cooling tower power consumption

Cooling towers are widely used in chemical industries to cool water with ambient air that is susceptible to weather changes not only during the day, but also during the year, resulting in challenges to cooling towers design and operation. In the design phase, the difficulties to determine the cooling tower capacity arise not only from the uncertainty of cooling water consumption but also from ambient temperature variations, which have a direct impact on the volume of cooling tower fill and fan power. Wide temperature variations can result in cooling towers that excessively cool water during significant portion of the year. Moreover, an oversized cooling tower brings challenges to the plant operation, since the cooling tower turndown must be high to account for the colder days. The mathematical model of cooling tower operation that is composed by mass and energy balances, and by cooling tower characteristic equations can be simulated to design cooling towers, and forecast their performances in four Brazilian cities (Manaus, Salvador, São Paulo and Porto Alegre). Analyzing the results enables the calculation of the cooling tower slack, and the required turndown during the year in these four cities. This work proposes strategies for cooling tower fan operation to reduce the slack, and estimates the electrical energy cost reduction if such strategies are implemented.

A New Method for Adjusting Setting Angle of Rotor Blade for Axial Fan in Wind Tunnel

Combining the fan aerodynamic efficiency with the wind tunnel pressure loss coefficient, a new equation which points out the inherent relationship of the fan blade setting angle, fan rotating speed and gas flow rate in wind tunnel circuit is derived according to the two-dimensional flow theory of the axial fan rotor blades and the aerodynamic characteristics of the low speed wind tunnel. So a new method for setting angle adjustment of fan rotor blade to satisfy the fan performance at off-design point by getting the test results of fan operation parameters but without the fan total pressure rise in the low speed wind tunnel is developed. Flowing the new method, the setting angle adjusting value of fan rotor blade was provided only with the fan rotating speed and flow velocity in the test section of a low speed wind tunnel directly before the fan setting angle altered, the adjusting target was achieved by the new blade setting angle successfully and the time and cost of the wind tunnel commissioning test were saved. The test results show that, after increasing the fan rotor blade setting angle by 4.5 degrees, when the flow velocity in the wind tunnel test section reaches 60 m/s, the fan rotating speed is 570 r/min, the deviation from the predicted fan rotating speed value of 575 r/min is 0.9%. For the same test section flow velocity, the predicted value of the fan rotating speed is in a good agreement with the real value, it proves that this method is reliable and accurate in practical application.

Experimental investigation on power consumption of an industrial fan with different flow control methods

AbstractBasically, fans and pumps are designed to be capable of meeting the maximum demand of the system in which they are installed. However, quite often the actual demand could vary and be much less than the designed capacity. Therefore, to operate the pumps and fans in lower capacity several methods of flow control systems have been used by industries nowadays. In this research, a study has been carried out to verify the power consumption of an industrial fan of a cement plant in different flow control systems. It is observed that the flow control system with variable speed drive (VSD) is the best among all the flow control system used in the industries nowadays. Also, the energy saving band is constructed by putting the results in software which depicts the range of operational speed with the corresponding power consumption to compass the idea for selecting a suitable method of speed control according to the specific flow rate requirements. It is also observed that the highest internal rate of return (IRR) is coming in VSD flow control method which is around 55% and the lowest IRR is coming in outlet damper flow control method which is around 21%. Noise level is also the lowest in VSD controlled method that is 65 dB and the highest in outlet damper control method that is 80 dB. Similar results are also found in carbon footprint study for 1 year (240 days) of operation of the industrial fan that is the lowest in VSD controlled method and the estimated value is 208.08 tons CO2 (tCO2) per year whereas the highest carbon footprint is estimated in outlet damper control method that is 381.48 tCO2 per year. Hence, we can conclude that by using an efficient flow control method like VSD system we can save energy as well as save our environment.