It is observed Fig.7 that the daily output of the system decreases when one increases the airchannel width of the heat exchanger. This is explained by the fact that the heat exchanges connectives internal in the sensor deteriorate, when the distance between absorber and insulating plate, increases, the mass flow of air being maintained constant.
This paper presents a mathematical model that has been developed to study the effect of the water storage tank volume and working fluids mass flow rate on the efficiency of a Hybrid Solar Collector (HSC) system for different Romania climates. The thermal storage system consists of three separate fully mixed tanks. It means that the temperature in the tank is uniform. The simulation results show that the system performance increases about 2.1% for a 500L volume of the storage tank with constant air flow rate 0.06 kg/s compared to the system with 300L volume of storage tank. Moreover, the HSC system performance is significantly affected by the airchannel shape. The efficiency of the HSC system can be improved through the use a large thermal storage system.
The working principle of this cooler principally is based on the modified M-cycle of IEC system in which fraction of the cooled supply air is diverted to the wet channel to became the working air. This configuration allows extra amount of energy to transport from both the dry- and wet-air passage instead of using the hot ambient air as working fluid. A cross-sectional view of the rig presents the working principles of the system is shown in Fig 1. The inlet air enters the dry airchannel (state 3) and passes through the finned heat pipe evaporators (HPE) (state 3) where the air is cooled down by transporting heat via the finned heat pipes to the wet channel, till just before the exit of the dry channel where part of the cooled inlet air is fractioned and diverted into the wet channel (state 6), while, the remaining part of the air stream is supplied to the conditioned room (state 5). In the upper duct, the heat pipe condensers (HPCs) are embedded in the ceramic tubes and filled up with water which is supplied at 23 ℃ via overhead tank, the water flow down and fill up the 3 mm cavity between the outer surface of the HPC and ceramic tubes providing even and complete covering of the condenser. Therefore, the cooled working air flows in counter-current pattern, over the wetted porous ceramic tubes, as the water starts to siphon through the micro pores of the ceramic forming a tiny water film over the ceramic surface, causing a drop in the water temperature and increase of the latent heat of the working air, this process attain constant remove of the heat which would accumulate in the water due to heat transport to the condenser surface. As result, the working air is rejected to the surroundings as hot and humid air (state 7).
Wind from the Sun could be a new technology for manufacturing wattage from a solar/wind hybrid system. an oversize solar furnace transforms energy from daylight to heat. The solar furnace heats the air on top of it and therefore the heated air will increase.Cooler air moves in to exchange the rising hot air and a cycle begins. The solar furnace frequentlyHeats the air, that rises and is changed by cooler air. The heated rising air decreases the gas pressure on top of the collector. The increasing hot air over the collector contains a lower gas pressure than the cooler air over the land removed from the collector.A large diameter pipe (or “airchannel”) connects the lower gas pressure, close to the center of the collector, to the upper gas pressure, a brief distance removed from the collector. Air moves from high to low gas pressure through the airchannel. within the airchannel, pressure-staged wind turbinesConvert the wind’s energy into electricity.
The hollow circular airchannel is made in inner foam of helmet for forcing the air in and out of the chamber directly. The passage is able to supply considerable amount of flowing air from outside the helmet during high speed travel. Basically, the air from the outside will push the air in the chamber into the helmet. Thus, a higher cooling rate will be achieved.
temperature in airchannel discharge; humidity measurement by using wet bulb thermometer and dry bulb thermometer (the measurements include outside air humidity and humidity after air passed heater, while relative air humidity can be known by using psychometric chart); air flow speed measurement in the drying chamber by using anemometer which was placed in front of air hole in the drying chamber (the measurements were in upper rack, middle rack, and lower rack); temperature stability observation to identify temperature transient response and temperature stability in the condition of instrument with load (it was done in three hours and 1 hour simulations for each drying process which is set in 60°C, and fermentation process which is set in 40°C); control precise observation by using timer in the control time movement from drying process to fermentation process; and weight reducing observation every three hours drying and 21 hours fermentation.
The experimental apparatus is used to investigate the hydraulic performance of the finned duct. The apparatus itself is designed to replicate as far as possible the flow characteristics of the industrial equipment, which com- prises the duct with its finning, and the fans causing the flow of air. The complementary instrumentation is fitted to facilitate the measurement of air pressure drop and flow rate. The tests are carried out under isothermal condi- tion.
This paper is interested in improving the BER performance of the single input single output (SISO) air-to-ground communications so; it takes advantages of the diversity gain resulting from the use of multiple antennas techniques. The main idea of spatial diversity techniques is to provide a diversity and/or coding gain by sending redundant signals over multiple transmit antennas. Alamouti was the pioneer in this area of research. He proposed a simple technique for two
At issue is the fact that nothing has been found wrong with the Channel Branch Office. As Mr. Yellow has pointed out, any and all tests have found nothing substandard. Nevertheless any recommendations that were made were met and/or exceeded. Office staff would not agree with this because the recommendation to remove the original ceiling tiles (that got wet do (sic) to a leaking roof) was not done throughout the entire office. Employees believe that the tiles in the south-east corner may be moldy and that may be cause for people feeling ill. (other tiles were removed) The office has a new drop ceiling throughout the office. There is no question that employees at the Channel office get ill. But employees in THE EMPLOYER’S Branch Offices from Marquette to Monroe become ill. There was no evidence presented to establish a greater illness percentage in the Channel office over any other Branch Office location.
It can be seen that the most solar radiation exists in June for Yazd province. Fig.4 shows the monthly solar intensity and the temperature values of ambient; Air out in top and bottom channels, absorber and average temperature of top and bottom channel. It is seen that at the time of maximum solar radiation, maximum air temperatures will occur in top and bottom of channel output in June. Also, The higher temperature difference between up and low channel is about 2.3 C . Results also show that the temperature output and average temperatures of upper channel is higher than low channel in all over the year because of higher heat capacity of the absorption of solar radiation in the glass. The average air temperature curve in top and low channels and the ambient temperature curve have approximately the same trend, but ambient temperature is lower than average channel temperatures as expected.
The unwanted environmental circumstances decrease the visibility and hidden information of theremotely sensed images. Since visibility is a significant quality issue in these images, thus, visibilityimprovement methods are necessary for improving the significant details of remotely sensed images. Thispaper has proposed a novel technique for improving the visibility of outdoor images. Theproposed method produces efficient results by using fuzzy filter based dark channel prior. The fuzzy filter can automatically extract the local atmospheric light and roughly eliminate theatmospheric veil in local detail enhancement. The proposed technique is designed and implemented usingin MATLAB with the help of image processing toolbox. The qualitative results have clearly show that theproposed image enhancement technique can preserve significant detail of the original image.
creased due to the reduction of adsorbed negative ions on the channel as shown in Figure 4(b). This corresponded to the result described above and in Figure 3. The results of the experiment showed that the nanoFET sensor could detect negative ions in air quantitatively and the concentration could be analyzed by the slope of the channel conductance change rate during a real-time measurement. However, the initial, so-called ‘ready, ’ level of I ds for the air ion measurement was not actively
Abstract. Numerical and experimental results on the thermal performance of vapor chamber with and without micro-channel under constant heat flux are presented. The mathematical model of the vapor chamber is a two-phase closed chamber with wick sheet and a wick column. A finite volume method with structured uniform grid method system is applied to solve the model. Effects of micro-channel on the temperature distribution of the vapor chamber are considered. The results obtained from the model are verified with those from the measured data. The experimental tests are carried out and good agreement is obtained with the numerical results. These numerical results are useful for the design to improvement thermal performance of the vapor chamber and also diminished the expense and time of the real test.
The paper presents computer modelling and laboratory experiment results of a sub-wet bulb temperature indirect evaporative cooling system for space cooling in buildings. The prototype employs hollow porous ceramic water containers as wet media material for water evaporation. The cooled air is delivered without increasing its moisture content. The performance of the cooler was evaluated using a computer model, and the results of which were validated experimentally. The cooling capacity and effectiveness of the cooler were evaluated at inlet air dry bulb temperature of 30 and 35 o C and relative humidity ranging from 35% to 50%. It was found that the cooler can supply air for space cooling at sub-wet bulb temperature conditions; achieve measured cooling capacity approaching 225 W/m 2 of exposed ceramic material wet surface area and wet bulb effectiveness higher than unity. The high thermal performance of the constructed evaporative cooler indicates the system could be a potential substitute to conventional mechanical air-conditioning systems in buildings in many parts of the world where hot and dry climatic conditions prevail.
Thus, more studies are being done to improve the thermal efficiency of the SAH systems by proposing the various ways of improving the heat transfer coefficients. Charters  considered the aspects of flow duct design for solar air heaters and pointed out that, there is no simple method to optimize the flow duct dimensions on purely technical considerations. Therefore, a combined technical and economical evaluation should be undertaken for each individual installation using the best cost and available local materials. Garg et al.  and Choudhury et al.  investigated the effect of channel depth on efficiency. Ho- Ming et al.  and Hegazy  performed a theoretical investigation on the effect of aspect ratio on the collector efficiency of solar heater systems. Bolaji  developed and evaluated the performance of a box type absorber solar air collector for crop drying. Lin et al.  carried out a parametric study to investigate the thermal performance of cross-corrugated solar air collectors. Many studies have been done both experimental and theoretical to improve the performance of solar heaters systems. Modeling and simulation are considered as fast and cheap analytical tools by engineers in developing optimal solar energy systems for a given application prior to their construction. This study involves modeling of a solar air heater system with trapezoidal corrugate absorber plate. The model is validated using the experimental values obtained from a prototype model built and tested outdoors.
College, 356-1, Hongeun2-dong Seodaemun-gu, Seoul 120-776, Korea Abstract—This paper presented an estimation method of maximum effective isotropic radiated power (EIRP) and electro-magnetic field (EMF) strength of a wideband code-division multiple-access (WCDMA) base station based on over-the-air measurements of a pilot channel in a code domain. To verify the feasibility of the proposed method, we estimated the maximum EIRP and EMF strengths of the self-designed test base station, and compared them with EIRP and EMF values measured by the traditional test scheme. Then, we applied our estimation scheme to the inspection test for a commercial base station. The maximum difference between the estimated EIRP values from our method and the reported values is 1.3 dB. The estimated EMF results show more than 90% agreement with both the traditional EMF measurement value under a full-traffic load condition and the theoretical value. Therefore, it can be concluded that our proposed estimation method should be an effective inspection test for domestic base stations.
To make it easier to identify and select the channels you want to listen to, channels are divided into 10 banks of 30 channels each. Use each channel- storage bank to group frequencies, such as those used by the police de- partment, fire department, ambulance services, or aircraft (see “Guide to the Action Bands” on Page 39). For exam- ple, the police department might use four frequencies, one for each side of town. You could program the police frequencies starting with Channel 1 (the first channel in bank 1) and pro- gram the fire department frequencies starting with Channel 31 (the first channel in bank 2).
To remove the lockout from a channel, manually select the channel and press L-OUT so L/O disappears from the display. Or, to unlock all channels or frequencies in the banks that are turned on, press MAN to stop scanning, then hold down L-OUT until the scanner beeps twice. Note: If you select a weather frequency by pressing WX and then lock out that frequency, the scanner stores the frequency in its search skip memory. Follow the steps under “Search Skip Memory” on Page 27 to remove the lockout from the weather frequency.