Air Pump Research Articles

Design and Development of Portable Wrist Rehabilitation Device for Post-Stroke Subjects: A Pilot Study

Wrist mobility is vital for post-stroke patients to carry out their daily activities. The use of robotic devices in hand rehabilitation has increased significantly in recent years, allowing patients to get training at home and effectively compensating for the therapist-to-patient ratio. Nevertheless, rehabilitation devices are expensive, cumbersome, immobile, and difficult to wear and operate. This work proposes a new method for designing a wrist rehabilitation device that uses airbag technology to minimize device weight and size. A triangular prism-shaped Neoprene (synthetic rubber) airbag is utilized in the experiment; which is inflated and deflated using a DC motorized air pump. An accelerometer sensor serves as the control input for the wrist rehabilitation exercise device. The proposed device trains the impaired hand of ten hemiplegic post-stroke patients. A goniometer and Fugl-Meyer Assessment (FMA) are used to measure wrist motion before and after the training regimen to evaluate the results. The mean angle (in degree) of wrist flexion increases from 8.6 ± 2.59 to 18.4 ± 5.19 (p = 0.005). Likewise, an increase in the wrist extension angle from 12.3 ± 3.62 to 17.7 ± 6.2 (p = 0.008) is noted. The wrist rehabilitation device is lightweight, portable, and simple to use, producing good results for hemiplegic individuals with hand disability. The suggested invention enables the user to extend their wrist’s range of motion.

Design and performance analysis of motor phase change heat storage heat pump system for new energy vehicles

Based on the work of air conditioners for new powerful cars, the author created a heat pump air conditioner with various functions, such as cooling and heating passengers, cooling and preheating the battery, defogging, defrosting, and PTC heating. Developed basic components of AC heat pumps such as scroll compressor model, running condenser model, combined evaporator model, plate evaporator extended valve model, and radial basis function neural network model for predicting compressor volumetric efficiency and isentropic efficiency. The accuracy of the gas-flow, gas-flow, and plate evaporator simulation model was verified. The maximum error between the experimental and simulated values of compressor power, heat exchanger, and system COP in various operating models is 0.34~10.09, which is consistent with the experimental results. correct and can be used for ventilation pump research. Also, an operational simulation analysis platform was used to analyze the performance of the heat pump and study the system characteristics. It is clear that this system provides more warmth to the occupants in the defrost mode, and current research on the operation of the air conditioning pump is based on the first law of thermodynamics.

Research on heat pump air conditioner compressor speed control strategy based on whale algorithm

Accurate control of compressor speed is crucial for enhancing the heating performance of heat pump air conditioning systems and extending the driving range of electric vehicles. Based on traditional PID control and fuzzy PID control strategies, a control system utilizing the WOA-PID (Whale Optimization Algorithm)fuzzy control strategy is proposed to regulate the compressor speed and achieve optimal passenger compartment temperature control.The results demonstrate that, compared to traditional PID control and fuzzy PID control, the WOA-PID fuzzy control strategy results in significantly reduced overshooting of the passenger compartment temperature, as well as increased COP (Coefficient Of Performance)values. Specifically, when the target temperature is set at 18 °C, the WOA-PID fuzzy control strategy achieves a temperature overshoot amount of only 0.01 °C, and increases the COP by 0.10 and 0.01 compared to traditional PID control and fuzzy PID control, respectively. Similarly, when the target temperature is set at 25 °C, the WOA-PID fuzzy control strategy achieves a temperature overshoot amount of only 0.08 °C, and increases the COP by 0.14 and 0.07 compared to traditional PID control and fuzzy PID control, respectively. These improvements optimize the maximum overshooting amount and adjustment time of the passenger compartment temperature, effectively enhancing the heating performance of the system.

Performance assessment and working fluid selection for heat recovery ejector heat pump system in cold climatic conditions

The paper aims to analyze the performance and identify suitable working fluids for a new heat recovery ejector heat pump (HREHP) system. This system introduces a flue gas waste exergy recover circuit combined with the traditional ejector heat pump. Considering the factors of performance, environmental impacts, flammability, and fluid type, four working fluids are selected (i.e., R245fa, R365mfc, RE245fa2, and R1233zd(E)). Comparative study initially conducted to demonstrate the advantages of the proposed heat recovery ejector heat pump facility. Subsequently, the effects of the operational parameters on the novel system performance are investigated to derive design and operation criteria through energy and exergy analysis. Finally, sensitive analysis of generation temperature (Tg), flue gas temperature (Tfg,out), and supply water temperature (Tw) on the proposed system is carried out. Compared with traditional air source heat pump, the application of the HREHP shows higher energy efficiency and lower operating costs at lower ambient temperatures. The results indicate that the primary energy efficiency of the proposed system is 27.0 % and 35.56 % higher than that of conventional ejector heat pump cycle and air source heat pump cycle, respectively, at an ambient temperature of −10 °C. Besides, Tg has a stronger effect on the entrainment ratio and heating coefficient of performance; The primary energy efficiency is more sensitive to Tw variation. Lastly, the R365mfc and R1233zd(E) show good potential as the alternative for the R245fa. The design methods, evaluation methods, and operational characteristics obtained in this study can provide reference and guidance for the application of heat recovery ejector heat pump technology in practical engineering.

Multi-anode enhanced the bioelectricity generation in air-cathode microbial fuel cells towards energy self-sustaining wastewater treatment

Microbial fuel cells (MFCs) hold considerable promise for harnessing the substantial energy resources present in wastewater. However, their practical application in wastewater treatment is limited by inadequate removal of organic matter and inefficient power recovery. Previous studies have investigated aeration as a method to enhance the removal of organic matter, but this method is energy-intensive. To address this issue, this study proposed using MFC-recovered bioelectricity for aeration, thereby mitigating the associated expenses. An air-cathode MFC with multi-anode was constructed and optimized to maximize electricity supply for aeration. Carbon-felt anodes were chosen as the most effective anode configuration, due to the high abundance of electroactive bacteria and genes observed in the biofilm generated on their surface. By incorporating six carbon felt anodes, the MFC achieved a 1.7 and 1.1 fold enhancement in the maximum power and current density, respectively. The optimized MFC unit achieved a stable current density of 0.32 A/m2 and achieved COD removal of 60% in the long-term operation of 140 days in a 50 L reactor. In a reactor scaled up to 1600 L, 72 MFCs successfully powered a mini air pump work for 10 s after an 81-s charging period. The intermittent aeration resulted in partial increases in DO concentrations to 0.03–3.5 mg/L, which is expected to promote the removal of nitrogen compounds by the nitrification-anammox process. These groundbreaking results lay the foundation for self-sustaining wastewater treatment technologies.

Fluid Dynamic Loss Model With Wide Applicability for Aeroengine Transmission Gears

Abstract In high-speed gear systems for aeroengines, it is important to reduce the fluid dynamic loss, which accounts for the majority of power loss, to improve fuel efficiency. For reasonable loss-reduction and the standardization of low-power-loss designs, a fluid dynamic loss model with wide applicability is needed. However, there are few reports of loss models considering the gear shroud effect on the oil dynamic loss. This study developed a loss model based on fluid dynamic loss phenomena. Specifically, fluid dynamic loss models were developed for the “air side-flow loss,” “air pumping loss,” “oil-jet acceleration loss,” and “oil re-acceleration loss” in the gear meshing part, and “air vortex loss” and “oil churning loss” in the gear peripheral part, with consideration to the shrouding effect. Moreover, an experimental method and a numerical method for loss classification are proposed. The fluid dynamic loss models were validated by experiments or experimentally validated numerical simulations. To demonstrate the effectiveness of the loss model for low-power-loss design, the influence of the design parameters was investigated, and the typical parameters were optimized.

A three-heat source segmented heating control strategy based on waste heat recovery technology for electric vehicles

The control strategy of thermal management systems is crucial for electric vehicles to ensure thermal comfort of the cabin and thermal safety of the battery and motor. However, this will also impact the energy consumption of the vehicle. In this study, a three-heat source segmented heating control strategy was proposed to reduce the heating energy consumption of electric vehicles, with the three sources denoted motor waste heat, air, and positive temperature coefficient (PTC) heaters. Specifically, a simulation model of an integrated thermal management system for heat pump air conditioning, motor thermal management, and battery thermal management systems was first established and validated using published experimental results. Subsequently, the performance of three cabin heating modes was investigated based on the standard driving cycle. The optimal opening and closing strategies for each mode were discussed to ensure the temperature requirements of the cabin, and the optimal method for using motor waste heat and the PTC heater to heat the battery at low temperatures was explored. The segmented heating control strategy was developed by determining the heating priority for the battery and cabin, as well as the heating capacity of heating modes using air source. Compared to the traditional heating strategy of the cabin and battery, the proposed control strategy could reduce energy consumption by 18.49 % while running at an ambient temperature of − 10 °C for 2.5 h.

FE-based Simulation of Radiated Noise for a Rotating Tire

Today, the significance of reducing pass-by noise is increasing steadily due to EU labeling regulations and the demands of car makers. As a result, numerous companies are actively conducting research to minimize pass-by noise. In this paper, we introduce a finite element method (FEM) prediction technique for reducing pass-by noise, aimed at reducing the time and cost involved in manufacturing, testing, and verifying pass-by noise. We have created a tire FE model that incorporates the full pitch sequence of the tire pattern, and used it to predict airborne noise (ABN) generated by air pumping and vibration due to the grooves in the pattern. The simulation environment was designed to match the test conditions in Hankook's anechoic chamber, and we compared the frequency spectrum of the simulation results with the actual test results. In conclusion, we have successfully performed FEM simulation of radiated noise, which accurately reflects the noise generation mechanism of rotating tires. This has improved the simulation accuracy for predicting airborne noise.

Study on integrated thermal management system of hydrogen fuel cell vehicles based on heat pump air conditioning

An integrated thermal management system (VITMS) of hydrogen fuel cell vehicle (FCV) is proposed to solve the issues of poor temperature control and high energy consumption in current dispersed TMS. The vehicle energy integration is realized by coupling the key subsystems of cabin, fuel cell, power battery and motor through the waste-heat source heat pump (WSHP). The temperature control capability under extreme working conditions are analyzed. The energy consumption of three heating modes under extreme cold conditions is evaluated. The results show that VITMS has excellent thermal control performance and can realize fourteen work modes such as cooling, heating, preheating, defrosting and energy recovery, ensuring the optimal temperature ranges and temperature uniformity of fuel cell, power battery, motor, and cabin. VITMS using WSHP offers superior energy saving effect in extreme cold conditions, which can reduce equivalent hydrogen consumption by 12.21% and 3.6%, and increase maximum driving range by 29.34% and 8% compared to PTC and air-source heat pump (ASHP). The cabin heating time using WSHP can be reduced by 34.5% compared to ASHP, ensuring all-weather ride comfort and extending the vehicle's driving range in low temperatures. Annual CO2 emission is 52.13% and 36.17% lower than diesel and electric buses.

Dynamic Low-Pressure Measurement Using a Fiber Optic-based Fabry-Perot Interferometer

A dynamic low-pressure measurement using a fiber optic-based Fabry-Perot Interferometer (FFPI) has been demonstrated in this work. The developed system has been divided into 2 main parts: pressure source and sensing system. The former is a chamber comprised of an elastic diaphragm, which proportionally deflects according to input pressure from an air pump. The FFPI, consequently, detects the material deflection and demodulates the parameter into useful pressure value via the fringe counting technique and Kirchhoff-Love’s plate theory. To validate the performance of the developed system, a reference pressure instrument is utilized while the air pump feeds pressure of 0.34–6.57 mbar with 10 times repeatability into the system. The experimental results indicated that the FFPI can measure the pressure of 0.343–6.568 mbar, while the reference instrument showed the output values from 0.343–6.471 mbar, respectively. Moreover, the average and maximum percentage error in measurement is 1.27% and 2.67%, respectively. The resolution of the FFPI sensor is also analyzed to be approximately 0.05% or 0.0382 mbar/μm over all measurement ranges. Therefore, we conclude that the FFPI has high accuracy, resolution, linearity, and reliability in dynamic low-pressure measurements.

Innovative process integrating high temperature heat pump and direct air capture

Direct air capture (DAC) technology plays a crucial role in mitigating the effects of global warming by capturing carbon dioxide (CO2) directly from the atmosphere. A significant technical challenge for DAC is its high thermal energy consumption, which results in an unacceptable overall cost (600$tCO2–1). The combination of a high-temperature heat pump (HTHP) and DAC system offers a substantial reduction in thermal energy consumption, decreased reliance on renewable energy sources, and enhanced DAC system flexibility. This study presents three distinct thermal integration strategies that combine an HTHP with solid adsorbent-based DAC and verifies their effectiveness in reducing energy consumption and CO2 emissions compared to a traditional DAC system. Among them, the deeply integrated DAC-HTHP system (I-DAC) exploits low-grade adsorption heat and waste heat, providing direct heating and cooling energy to the DAC system via refrigerant condensation and evaporation processes. Simulation results indicate that the I-DAC system achieves an extremely low operating energy consumption of 2.77 GJtCO2–1, representing a 69.5% reduction than traditional DAC under the same conditions. Consequently, the I-DAC offers a cost-effective (32.0–46.2 $tCO2–1) negative emission solution. We also demonstrate that the I-DAC is promising for wide application in cities to recycle waste heat and remove CO2 from the air. The comprehensive implementation of the I-DAC in 105 cities could yield a net annual productivity of 980 MtCO2.

Levofloxacin dry powder inhaler for high dose delivery

Mucous plugs in the respiratory system of cystic fibrosis patients are often infected, typically by Pseudomonas aeruginosa. Nebulized levofloxacin is effective against P. aeruginosa, but the administration and cleaning process is time-consuming. To address this limitation, dry powder inhalers are a potential alternative if a high required dose could be loaded. The objective of this study was to develop and characterize an excipient-free levofloxacin powder produced by a solvent-free spray drying method. The obtained particles were small, rounded and crystalline. Under pharmacopoeial impactor conditions, high emitted, fine particle and respirable fractions were achieved, even with high drug loadings. Variations in the impactor pump's air flowrate did not significantly affect the aerodynamic performance. After 12 months' storage critical attributes remained largely unchanged. The developed system allows for the same dose delivery as the marketed product for nebulization using only four capsules, highlighting its potential in cystic fibrosis treatments.

Application of artificial intelligence algorithms and low-cost sensors to estimate respirable dust in the workplace

The Internet of Things (IoT) and low-cost sensor technology have become common tools for environmental exposure monitoring; however, their application in measuring respirable dust (RD) in the workplace remains limited. This study aimed to develop a predictive model for RD using artificial intelligence (AI) algorithms and low-cost sensors and subsequently assess its validity using a standard sampling approach. Various low-cost sensors were combined into an RD sensor module and mounted on a portable aerosol monitor (GRIMM 11-D) for two weeks. AI algorithms were used to capture data per minute over 14 days to establish predictive RD models. The best-fitting model was validated using an aluminum cyclone equipped with an air pump and polytetrafluoroethylene filters to sample the 8-hour RD for 5 days at an aircraft manufacturing company. This module was continuously monitored for two weeks to evaluate its stability. The RD concentration measured by GRIMM 11-D in a general outdoor environment over two weeks was 28.1 ± 16.1 μg/m3 (range: 2.4–85.3 μg/m3). Among the various established models, random forest regression was observed to have the best prediction capacity (R2 = 0.97 and root mean square error = 2.82 μg/m3) in comparison to the other 19 methods. Field-based validation revealed that the predicted RD concentration (35.9 ± 4.1 μg/m3, range: 32.7–42.9 μg/m3) closely approximated the results obtained by the traditional method (38.1 ± 8.9 μg/m3, range: 28.1–52.5 μg/m3), and a strong positive Spearman correlation was observed between the two (rs = 0.70). The average bias was −2.2 μg/m3 and the precision was 5.8 μg/m3, resulting in an accuracy of 6.2 μg/m3 (94.2 %). Data completeness was 99.7 % during the continuous two-week monitoring period. The developed sensor module of RD exhibited excellent predictive performance and good data stability that can be applied to exposure assessments in occupational epidemiological studies.

Fog Water Collection for Local Greenhouse Vegetable Production in the Atacama Desert

Agricultural production in the Atacama Desert is restricted by extreme aridity and poor soil quality. Between 18° S and 30° S, low stratocumulus clouds regularly cover the southeastern Pacific Ocean reaching the Coastal Cordillera. Thus, marine fog is constantly present in the coastal areas of the desert. Fog can be harvested using fog collectors. However, limited information is available with regards to the variability of fog presence throughout the year and along the coast of the desert. Combining fog water harvest with hydroponic production under greenhouse facilities presents an alternative for sustainable and local fresh food production. In this article, we analyze the potential of fog water collection in two sites (Alto Patache and Falda Verde) distant by about 1000 km within the Atacama Desert. Additionally, in both locations, the environmental conditions within greenhouse structures, the potential energy requirement for environmental conditioning (including the energy production from photovoltaic panels) and the water requirements of vegetable crops under greenhouse conditions were modeled. The annual average of fog water collection registered was 2.9 and 3.3 L per day per m2 in Alto Patache and Falda Verde, respectively. During the most demanding season for crop evapotranspiration, 2.13 m2 of fog collectors can supply the water required for 1 m2 of greenhouse crops. The energy required for water and air pumps in the hydroponic systems can be supplied with photovoltaic systems including eight PV modules and a battery storage capacity of 9.4 kWh. In conclusion, the present study sheds light on the possibilities of massive water collection from fog to be used in local and sustainable food production in the Atacama Desert.

Energy-saving Optimization of Frequency-variable Heat Pump Air Conditioning System for Electric Vehicles Based on a Genetic Algorithm

Energy-saving Optimization of Frequency-variable Heat Pump Air Conditioning System for Electric Vehicles Based on a Genetic Algorithm

Inactivation of Avian Influenza Virus Aerosol Using Membrane-Less Electrolyzed Water Spraying

Avian influenza virus (AIV) can have a serious impact on both human and animal health. In this study, we used an environmentally controlled chamber and a hemagglutination assay (HA) to evaluate the ability of membrane-less electrolyzed water (MLEW) spraying to inactivate H6N1 AIV aerosol. MLEW was generated by electrolyzing sodium chloride solution, and then sprayed into the chamber at free available chlorine (FAC) concentrations of 50, 100 and 200 mg/L by means of high-pressure air pumping to inactivate airborne H6N1 AIV aerosols individually. The results showed that MLEW spraying effectively neutralized H6N1 AIV aerosol. In addition, the virucidal ability of MLEW increased as the FAC concentration increased. Five minutes after MLEW spraying at an FAC concentration of 200 mg/L, the H6N1 viral HA titer decreased from 24 to 20. Our work provides important new evidence of the value of spraying with MLEW disinfectant to protect against AIV, which may be further applied for indoor decontamination purposes to promote animal and human health.

Exergy analysis of heat pump air conditioning systems for pure electric vehicle use with low-GWP refrigerants

The exergy analysis of low-global warming potential (GWP) alternative refrigerants, R1234yf, R152a and R744 for heat pump air conditioning (HPAC) systems used in pure electric vehicles (EVs) is conducted via simulation. The results reveal that the system exergy efficiencies (SEEs) of R1234yf-HPAC and R152a-HPAC under identical cooling or heating capacity are similar due to their close thermodynamic properties. The largest exergy destruction component in R1234yf- and R152a-HPACs is the compressor. While for R744-HPAC, the compressor and expansion valve cause major exergy destruction. Moreover, the results also indicate that the SEE of R744-HPAC is at least 20 % lower than that of R1234yf-HPAC when producing identical cooling capacity, while it is on average twice that of R1234-HPAC when producing identical heating capacity. Furthermore, the measures to improve SEE of HPAC systems with different refrigerants are discussed by examining the effects of varying operating conditions. It is suggested to lower compressor speed under both cooling and heating conditions, increase condenser airflow or reduce evaporator airflow of R1234yf-, R152a- and R744-HPACs under cooling condition; for cabin heating, it is advisable to increase the evaporator airflow or decrease condenser airflow for R1234yf- and R152a- HPACs and enlarge condenser airflow for R744-HPAC to elevate SEE.

Analysis of a rotary pump with two sectional impellers

The presented study shows aspects related to the fluid flow inside a rotary machine; this type of machine can be utilized as a ventilator, air pump or blower. Relations for computing the driving power of this pump as well as the fluid flow rate of transported are presented. The sealing between the impellers and between the impellers and the machine casing is studied and the advantages of different types of impeller shapes are specified.

Quasi-Biweekly Oscillation of Surface Sensible Heating over the Central-Eastern Tibetan Plateau and Its Relationship with Spring Rainfall in China

Abstract This study examines the characteristics and phase evolution of the quasi-biweekly oscillation of surface sensible heating (SH) over the central-eastern Tibetan Plateau (CETP) during spring. The mechanism connecting CETP SH to spring rainfall in China on the quasi-biweekly time scale is further investigated. Results show that the dominant mode of quasi-biweekly CETP SH presents a monopole pattern, in which the peak leads the maximum of the quasi-biweekly rainfall in the middle and lower reaches of the Yangtze River (MLYR) and South China by approximately 5 and 7 days, respectively. As an upper-level Rossby wave train propagates eastward, an anomalous center of convergence moves to the CETP, which leads to a strong downdraft and reduced cloud cover. The resultant elevated shortwave radiation input and drier soil conditions are favorable for the CETP SH quasi-biweekly oscillation to enter a positive phase. When reaching its peak, the CETP SH efficiently heats the lower atmosphere, resulting in a local updraft. Due to the “SH-driven air pump” effect, abundant water vapor is transported from the oceans to China. A lower-layer southerly anomaly on the east side of the TP develops into an anomalous cyclonic circulation via the effect of topographic friction, which leads to the expansion of the positive potential vorticity anomaly and the maximum of the quasi-biweekly rainfall in the MLYR. Further southeastward propagation of the wave train leads to a shift in the rainfall anomaly center to South China. These findings suggest that the CETP monopole SH warming could be a good indicator for predicting intraseasonal variations in spring rainfall over China.

Performance characteristics of a compact self-circulating liquid desiccant air dehumidification system coupled with a heat pump: A comprehensive parametric study

Integration of a heat pump with a liquid desiccant system for air dehumidification has received growing attention in recent years in view of its more compact size and lower electricity consumption. This paper presents a compact combined heat pump and self-circulating liquid desiccant air dehumidification system targeted at small cooling load applications. The compactness lies in the integration of the dehumidifier and evaporator as well as the integration of the regenerator and condenser. Besides, the design of solution self-circulation (SSC) is intended for energy savings and the auxiliaries are employed to help achieve energy matching between the heat pump and the air dehumidification system. First, a comparative study is performed to identify the more energy efficient one of the two strategies for energy matching. Based on this, a thermodynamic model-based parametric study is conducted to investigate the effects of various influencing factors on the energy matching relationship and performance of the proposed system, as well as the energy-saving potential relative to the basic system without SSC. The results show that there exists an optimum solution self-circulation ratio (SCR) to achieve the maximum COP under a given condition. Basically, the proposed system with a proper SCR could yield a significant energy-saving effect regardless of the performance variations under studied operation conditions. It is found that a reduction of 29.68 % in energy consumption and an improvement of 42.20 % in COP are achieved under the ambient condition of 30 ℃ temperature and 20 g/kg humidity ratio. Furthermore, a correlation analysis is used to reveal the association strength and direction between any two main operation and performance parameters. Finally, the heat recovery is proved to effectively reduce the cooling coils load. This paper provides an in-depth understanding of the energy matching relationship and demonstrates the energy-saving performance benefiting from SSC for future practical applications of the proposed system.