Characterizing the performance of a DIY air filter

Air filtration serves to reduce concentrations of particles in indoor environments. Most standalone, also referred to as portable or in-room, air filtration systems use HEPA filters, and cost generally scales with the clean air delivery rate. A 'do-it-yourself' lower-cost alternative, known as the Corsi-Rosenthal Box, that uses MERV-13 filters coupled with a box fan has been recently proposed, but lacks systematic performance characterization. We have characterized the performance of a five-panel Corsi-Rosenthal air filter. Measurements of size-resolved and overall decay rates of aerosol particles larger than 0.5 microns emitted into rooms of varying size with and without the air filter allowed for determination of the apparent clean air delivery rate, both as a function of size and integrated across particle sizes. The measurements made in the different rooms produced similar results, demonstrating the robustness of the method used. The size-integrated apparent clean air delivery rate increases with fan speed, from about 600 to 850 ft3 min-1 (1019 to 1444 m3 h-1). Overall, our results demonstrate that the Corsi-Rosenthal filter efficiently reduces suspended particle concentrations in indoor environments.

Flow Disturbing to Enhance Heat Transfer Inside a Duct: an Experimental Study

In the present experimental work, the effect of air circulation on increasing heat transfer rates within the duct was studied. Three air circulation speeds are implemented: 2400, 1800, and 1200 rpm. In addition, the effect of the distance between the heat source and the location of the circulating fan on heat transfer rates was investigated using three different distances: 20, 40, and 60 cm. The Exhaust fan, placed at the outlet of the duct, changed its speed to three values: 2850, 2140, and 1425 revolutions per minute. The Reynolds range ranged from 65,000 to 175,000. The results showed that the best thermal performance is achieved when the exhaust fan speed, air circulation speed, and the distance between the heat source are 1425 rpm, 2400 rpm, and 60 cm, respectively.

Reengineering Cracker-Dryer Machine Based on Fan speed and Temperature Considering Drying Time, Final Weight and Energy Consumption Factor

Redesign and building a cracker drying machine should give priority to several factors to find the optimal point, one of which is by conducting experimental experiments. This research was carried out to find out from the tool and also pay attention to several things, such as temperature and fan speed. If one of these factors is ignored, it will not produce dry crackers and the dried crackers are less than optimal. The Independent parameters used in this research are temperature and fan speed. Dependent parameters used in this research are concerning drying time, final weight, and energy consumption. Design experiment using Factorial 3x3. Fan speed has 3 levels, they are 1000rpm, 1500rpm and 2000rpm. The Temperature parameter has 3 levels, they are 16, 19, and 21oC. Based on the design of experiment results, it was found that the drying time response for the combination that has the highest ranking is at a temperature of 19oC with a 2000rpm fan speed resulting in a drying time of 182,677 minutes.

Pengaruh Kecepatan Fluida Pendingin (Udara) Terhadap Unjuk Kerja Dan Karakteristik Perpindahan Panas Pada Radiator Sepeda Motor Yamaha Nmax 155CC

Penelitian ini menggunakan metode ɛ-NTU untuk menganalisis data. Radiator yang digunakan adalah radiator sepeda motor Yamaha Nmax 155cc dengan jenis aliran vertical, flat tube dan louvered fins, kipas/fan sebagai sumber angin simulasi, dengan campuran 50% air + 50% coolant radiator. Laju aliran air konstan 4 lpm dan temperatur fluida panas konstan 80. Variasi kecepatan aliran udara yang digunakan pada pengujian kali ini adalah 4-8 m/s dan diatur menggunakan Dimmer sebagai alat bantu. Dari pengujian yang telah dilakukan didapat laju massa aliran udara yang paling besar terjadi pada kecepatan kipas 8 m/s. Laju perpindahan panas yang paling besar terjadi dikecepatan kipas 8 m/s sebesar 0,0735 kW dan panas menyeluruh terbesar juga terjadi dikecepatan kipas 8 m/s yaitu sebesar 9,50 W/m2°C. Efisiensi radiator maksimum terjadi pada kecepatan kipas 5 m/s dengan nilai sebesar 7,59. Kata kunci: Efektifitas, Metode ε-NTU, Radiator Nmax 155cc. This study uses the ε-NTU method to analyze the data. The radiator used is a 155cc Yamaha Nmax motorcycle radiator with vertical flow type, flat tube and louvered fins, fan/fan as a simulation source, with a mixture of 50% water + 50% coolant radiator. The water flow rate is constant 4 lpm and the hot fluid temperature is constant 80℃. The variation of air flow velocity used in this test is 4-8 m/s and is adjusted using a dimmer as a tool. From the tests that have been carried out, the largest air flow rate occurs at a fan speed of 8 m/s. The highest heat transfer rate occurs at a fan speed of 8 m/s at 0.0735 kW and the largest overall heat also occurs at a fan speed of 8 m/s at 9.50 W/m2°C. The maximum radiator efficiency occurs at a fan speed of 5 m/s with a value of 7.59 Keywords: Effectivenes, ɛ-NTU Method, Nmax 155cc Radiator

Energy Efficiency Ratio Analysis of Half Cycle Air-Conditioners Using Liquified Petroleum Gas

Alternative fuels have proven to be an effective means of reducing the environmental impact of road transportation. On the other hand, the increasing use of air conditioning has declined the fuel economy of passenger vehicles. Half-cycle air conditioning systems (HCACSs) can address this concern of the declining fuel economy by using the fuel as a refrigerant. One of the candidates to be considered as refrigerants in HCACSs is liquefied petroleum gas (LPG). Under various conditions, LPG in the liquid state is injected into the evaporator of an HCACS. At the end of the evaporation process, LPG vapors can be directed for the combustion taking place in devices such as generators, automobiles, and cooking stoves. The present study investigates the performance of three in-housed manufactured evaporators having staggered and/or aligned tube arrangements with variable tube sizes, numbers of fins, fin spacings, and fin materials. As a refrigerant, LPG, having 65% propane and 35% butane, was passed through three evaporators. The energy efficiency ratios (EERs) were indirectly measured for evaporative pressures of 132, 168, and 201 kPa, with mass flow rates of 0.6, 0.75, and 0.9 g/s, respectively, when the fan speed interacting with the evaporators was varied. The results revealed that the aligned configuration with the same tube and fin material performed better even at low fan speeds.

Optimize Thermal Management And Experiment Of Lifepo4 Battery Pack For Hybrid Electrical Vehicle

Hybrid Electric Vehicles (HEV) combines the benefits of gasoline engines and electric motors which can be configured for improving fuel efficiency. Lithium Iron Phosphate (LiFePO4) Phosphate based technology possesses superior thermal and chemical stability which provides better safety characteristics than those of Lithium-ion technology made with other cathode materials. This research conducted by two methods , methods of part 1 is a comparison of the results with the thermal management simulation and experiment, part 2 is a method of optimizing the thermal management for battery pack by using solidwork software. When the fan is on, the forced air flow over the cells removes some of the generated heat. Results of method part 1 is simulation more heat than experiment in the amount of 0.11% – 1.56%. The results of the method part 2 is simulated using the fan 4 fan with a speed of 415 rad/s and battery gap 30mm most efficient compared with 4 fans the other , while the simulation using 6 fan, fan speed 415 rad/s and battery gap 30mm most efficient for all.

Laboratory and Greenhouse Performance of Five Commercial Light Traps for Capturing Mosquitoes in China

ABSTRACT Mosquito light traps for household use are popular because they are small, cheap, user friendly, and environment friendly. At present, there are many variations and specifications of mosquito traps intended for household use on the market. The light traps claim they are powerful, but research and evaluation are lacking. Key parameters such as capture rates in the laboratory and field of 5 popular mosquito traps were evaluated as intended for household use. This study found that in the laboratory experiments, the capture rate of the mosquito traps selected was between 34.7% and 65.0%. Field tests in greenhouses found that the 5 mosquito traps had high catch rates for Culex quinquefasciatus. The percentage of Cx. quinquefasciatus, Aedes albopictus, Anopheles sinensis, and other flying insects captured was 51.76%, 25.29%, 14.12%, and 8.82%, respectively. There was no significant difference in the capture rate of Ae. albopictus and An. sinensis by the 5 mosquito traps in the greenhouse, but a significant difference in the catch rate of Cx. quinquefasciatus. The analysis showed that the fan speed and design of the air guide of the traps are important factors that affect the mosquito catch rate and that the ultraviolet wavelength (395–400 nm) used by the traps did not impact mosquito catch rates. Therefore, the mosquito traps intended for household use can be improved by adjusting the fan speed and optimizing the air guide.

Multi-model structured H-infinity design of a robust and aggressive turbofan jet engine controller

Jet engine control comprises tracking either the fan speed or engine pressure ratio setpoints. Further, safe operation entails maintaining several additional parameters, such as high-pressure turbine temperature, combustor pressure, core shaft acceleration and other ones within prescribed limits. A Min-Max selector that features PI controllers is frequently used to handle these requirements. However, this arrangement is overly conservative in the limits management, which unnecessarily slows down the engine response. To overcome this shortcoming, a new controller that adopts the traditional Min-Max structure in combination with the Ndot control, the Conditionally Active and the Conditioning Technique approaches is developed. PI regulators are replaced by dynamic output feedback controllers, which are designed according to a multi-model structured H-infinity methodology. This approach makes it possible to marry robustness with performance, which are two conflicting objectives. Singular value analysis tools demonstrate the robustness of the resulting design. Linear and nonlinear simulations indicate that the proposed controller optimizes the engine response time under the constraint of keeping a set of parameters within prescribed bounds. The features of the proposed design are lucrative for actual implementation in the industry.

Design of Smoke Alarm Disperser Based on Single-chip Microcomputer

With the rapid development of society and economy, various laboratories have become more complete in number and equipment, but subsequent laboratory accidents frequently occur. Therefore, it is imperative to construct a laboratory safety management system to ensure the safety of laboratory personnel and complete equipment. This article intends to design a smoke alarm, which mainly includes measuring the sensitivity of the smoke sensor to the concentration of smoke in the air, and the linear change of the sensor converting the corresponding analog signal into a digital signal. By designing the fan speed to be controlled by the change of smoke density, the speed of the motor is adjusted. And the alarm module can sound an alarm when the smoke concentration is certain, and at the same time, it can automatically cancel the alarm when the smoke concentration decreases. Finally, a simulation experiment is designed to simulate the effect of the sound alarm of the smoke alarm disperser on the dispersal of smoke under different working environments.