Percent Increase In Efficiency Research Articles

Insight into variable thermophysical features of the functionally graded porous annular fin influenced by internal heat and thermal radiation

The present analysis considers a functionally graded porous fin of radiating shape. The fin is subject to thermal-dependent internal heat generation and radiation. Two different cases are performed where the thermal conductivity varies linearly and exponentially with temperature. For simplicity, it is assumed that the material properties of the porous fin change along the fin radius based on a power-law function, with a consistent Poisson’s ratio. The Fourier’s law and Darcy model are used to model the ordinary differential equation (ODE) that governs the fin problem. The equation’s components have been arranged into dimensionless parameters, and their effects on fin efficiency, thermal stresses, and heat transfer rate are discussed and illustrated visually. The analysis comprehensively addresses the radial and tangential stresses and their thermal effects on the fin. It shows that near the base region of the fin, the tangential stress demonstrates less compression, and near the tip radius, there is smaller tensile stress. It has been found that for heat generation coefficient G=0.1 and εG=0.1 the percentage increase in efficiency is 28.1927%.

Evaluation and Improvement of Business Processes in the Operational Division Using Business Process Improvement (BPI) (Case Study: PT. Mitrasukses Engineering Indonesia

PT. Mitrasukses Engineering Indonesia (MEI) is a manufacturing company specializing in custom machine production. The company has an operational division responsible for managing product orders until they are delivered. The main problem in the operational division of PT. MEI is the inconsistency between product designs and customer needs, leading to machine design redesigns and delays in order processing. Therefore, a more detailed analysis of potential errors is required, followed by recommendations for improvement through business process improvement. The methodology used to analyze potential errors is the Failure Mode and Effect Analysis (FMEA) method. Meanwhile, the methodology used to provide improvement recommendations is the Business Process Improvement (BPI) method with the streamlining tools. The improvement measures adopted include streamlining tools such as Standardization, Upgrading, Simplification, Automation, and Error Proofing. Simulations will be conducted after modeling the improved business process based on the improvement recommendations. The simulations compare the time between the current business process model (as-is) and the improved business process model (to-be) to determine the percentage increase in efficiency. Efficiency occurs due to changes in process activities in the current business process that has been improved. The simulation results indicate an efficiency improvement in the product ordering process by 16.58%, material procurement process by 35.37%, production process by 38.85%, and product delivery process by 22.42%.

Thermal cooling of photovoltaic panels using porous material

An effective photovoltaic thermal regulation technique using porous material confined at the backside of the panel is proposed. Numerical thermal analysis was conducted to study the case of a steady-state mixed convection heat transfer with solar radiation using ANSYS® Fluent. Discrete Ordinate (DO) model was validated and used to simulate actual solar radiation on a 2-D model. The investigation addressed the effect of the convective parameter (λ), Darcy number (Da), inclination angel (θ), porous thickness ratio (S p/S), and emissivity (ϵ) on the average Nusselt number at the tedlar layer and the conversion efficiency (η) of the PV module. Compared to the clear domain, it was found that for three porous fins, five porous fins and porous layer cases the percent increase in efficiency was 6.73%, 9.19%, and 8.34%, respectively. Also, the buoyant effect overcame the friction effect in the natural-dominant regime and the percent decrease in the friction was 138.52%, 206.22%, and 118.64%, respectively for the same porous configuration order. It was also found that increasing the emissivity (ϵ) of the duct base wall enhances the cooling effect as it dissipates heat from the domain.

Experimental Study of Jet Impinging Double-Pass Solar Air Heater Using Wire-Mesh. (Dept. M)

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Enhancing the Performance of the Standalone Rooftop SPV Module during Peak Solar Irradiance and Ambient Temperature by the Active Cooling of the Rear Surface with Spraying Water and the Front Surface with Overflowing Water

The usage of the solar photovoltaic (SPV) module to meet the power demands, especially in residential and office buildings, is inevitable in forthcoming years. The objective of this study is to experimentally investigate the possibility of improving the performance of the standalone rooftop SPV module used in the residential and office buildings during peak solar irradiance and ambient temperature with active cooling of the rear surface alone by spraying water and the front surface alone by water overflowing over it and cooling of the rear and the front surfaces simultaneously. The underneath of the SPV module is attached with a tray with a length of 1580 mm, a width of 640 mm, and a depth of 100 mm. It is filled with 40-70 litres of water. Accouters are made for water overflowing from the tube over the front surface of the module and cooling of the rear surface by spraying water. The rear surface cooling, front surface cooling, and simultaneous cooling of both the surfaces reduce the average operating temperature of the module by 15.52°C (maximum 18.6°C), 24.29°C (maximum 28.7°C), and 28.52°C (maximum 34.7°C), respectively. This temperature reduction leads to the increase in the power output of the 150 W module by 10.70 W, 18.48 W, and 20.56 W and percentage increase in efficiency by 8.778%, 15.278%, and 16.895% for rear, front, and simultaneous cooling of surfaces, respectively. The net power output of the module with the front surface cooling by overflowing (0.9 litre/min) water is higher, i.e., 15.88 W/150 W, and produces installation capacity of 0.4234 watt-hour (Wh) of more energy per watt during the test period 10 AM to 2 PM in a day. The recommended cooling methods eliminate the need for freshwater and separate arrangements to dissipate the heat carried by the circulated water and reduced the power required and quantity of water circulated. They also reduced the heat loads of the room by the shadow effect and by maintaining the tray water above the roof.

Implementation of New Designs to Improve Efficiency of Solar Panels

As non-renewable energy resources are decreasing and becoming less feasible for long term use, the need for renewable resources for producing electricity is increasing. Options of renewable energy include wind farms, harvesting tidal energy, utilizing nuclear power and the use of solar panels. The problem with some of these options is that they are potentially hazardous, or that they might not produce enough power. However, solar panels are gaining popularity. Solar panels absorb energy from incident sun-rays and store it in batteries. In order to ensure peak efficiency, the panel must be perpendicular to the Sun in order to absorb maximum sunlight. This implies that the solar panel needs to continuously rotate in accordance to the Suns position as it traverses through the sky. This can be done with the help of a sun tracking system. Sun tracking systems are not a new concept, but our proposed design excludes the use of any microprocessor, that are used in conventional designs. Not using any computational device means that there is no need for an external power source. Thus making our proposed design a completely autonomous, stand alone system capable of performing at high efficiency without external power or intervention. Using the above mentioned technique and a few others, we predict a thirty percent increase in efficiency over industry standards.

Optimization of B-series propeller geometry dimension to improve traditional fishing ship performance

The fishing ship propulsion system will affect the performance of the ship and impact the fishermen’s income. A crucial factor is the level of efficiency produced by propellers mounted on fishing vessels. In B-series propellers, propeller efficiency can be optimized by varying the size of the geometric dimensions. This propeller optimization process can be done after the ship resistance value is known. In Cirebon waters, as in other regions in Indonesia, the selection of propellers by fishermen is still unclear. Most are only based on the availability of goods on the market, without looking at how big the actual ship resistance occurs. In this research, one of the fishing boats that will be built will be chosen to estimate the ships’ resistance. After that, by considering the engine used as its driving source, the geometry dimensions that can produce the highest efficiency are sought. Estimation of ship resistance is sought by the Holtrop method, and propeller optimization is carried out with the help of software. From the results of this study, the value of ship resistance commonly used by Cirebon waters fishermen is 2.608 kN at an operational speed of 7 knots. Optimized propeller design provides a 6 percent increase in efficiency compared to previously used propellers.

Centrifugal Compressor Performance Improvement through Multi Splitter Impeller

Abstract In the paper, a back swept impeller of centrifugal compressor is experimentally studied and numerically validated and modified to increase its pressure ratio and improve efficiency, as well as to analyse the effect of splitter blade location between two main blades. The back swept multi splitter blade impeller was designed with a big splitter positioned close to the main blade suction surface and a smaller splitter close to the pressure surface. Adding this multi splitter improves the overall performance of the modified impeller due to less intensive flow separation and smaller pressure loss. In particular, the total pressure ratio was observed to increase from 4.1 to 4.4, with one percent increase in efficiency.

Experimental Evaluation of an Internally Passively Pressurized Circulation Control Propeller

The purpose of circulation control for fixed wing aircrafts is to increase the lifting force when large lifting forces and/or slow speeds are required, such as at takeoff and landing. Wing flaps and slats are used on almost all fixed-wing aircraft. While effective in increasing lift, they do so with penalty of increasing drag, weight, and control complexity. The goal of this research was to find an alternative way of pumping pressurized air to the trailing edge slot on a UAV propeller. This design called for rerouting stagnation pressure from the frontal propeller area through the inside of the propeller blades to ejection slots on the trailing edge. This allows for the forward velocity of the aircraft to drive the pressurization of the circulation control plenum passively, without additional hardware. For this study, a Clark-Y airfoil section propeller with an overall diameter of 0.609 meters was designed and tested. The comparison of the augmented to unaugmented propeller showed a 5.12 percent increase in efficiency, which is shown to act over the entire range of flight envelopes of the aircraft and is shown to be particularly beneficial at advance ratios above 0.30, normal operating conditions of propeller-driven UAVs.

Experimental energetic analysis of a vapor compression refrigeration system with dedicated mechanical sub-cooling

In this work, an experimental investigation into the effects, in terms of energy, of employing a dedicated mechanical subcooling cycle with a residential 1.5ton simple vapor compression refrigeration system is presented. A comparative analysis of the experimental cycle performance is conducted with and without the dedicated subcooler cycle when the room temperature is kept between 18 and 22°C. This is done in order to ascertain the percentage increase in efficiency due to use of a dedicated subcooling loop. R22 is employed as the refrigerant in the main cycle whereas R12 is flowing in the dedicated subcooling cycle. The experimental outcomes indicate that the load carrying capacity of the evaporator increased by approximately 0.5kW when R22 was subcooled, in the main cycle, by 5–8°C. It was also noted that, by using the subcooling, the second-law efficiency of the cycle increased by an average of 21%. Furthermore, the general trend indicated that this percentage increase is inversely proportional to the ambient temperature variation. The experimental work proves that dedicated subcooling can be used for increasing cooling capacity and efficiency.

Mesh partitioning for efficient use of distributed systems

Mesh partitioning for homogeneous systems has been studied extensively; however, mesh partitioning for distributed systems is a relatively new area of research. To ensure efficient execution on a distributed system, the heterogeneities in the processor and network performance must be taken into consideration in the partitioning process; equal size subdomains and small cut set size, which results from conventional mesh partitioning, are no longer the primary goals. In this paper, we address various issues related to mesh partitioning for distributed systems. These issues include the metric used to compare different partitions, efficiency of the application executing on a distributed system, and the advantage of exploiting heterogeneity in network performance. We present a tool called PART, for automatic mesh partitioning for distributed systems. The novel feature of PART is that it considers heterogeneities in the application and the distributed system. Simulated annealing is used in PART to perform the backtracking search for desired partitions. While it is well-known that simulated annealing is computationally intensive, we describe the parallel version of simulated annealing that is used with PART. The results of the parallelization exhibit superlinear speedup in most cases and nearly perfect speedup for the remaining cases. Experimental results are also presented for partitioning regular and irregular finite element meshes for an explicit, nonlinear finite element application, called WHAMS2D, executing on a distributed system consisting of two IBM SPs with different processors. The results from the regular problems indicate a 33 to 46 percent increase in efficiency when processor performance is considered as compared to the conventional even partitioning. The results indicate a 5 to 15 percent increase in efficiency when network performance is considered as compared to considering only processor performance; this is significant given that the optimal improvement is 15 percent for this application. The results from the irregular problem indicate up to 36 percent increase in efficiency when processor and network performance are considered as compared to even partitioning.

Postnatal Changes in Proximal and Distal Tubular Sodium Reabsorption in Healthy Very-Low-Birth-Weight Infants

We studied 7 healthy very-low-birth-weight male infants with a mean birth weight of 1,195 g and a gestational age of 29.0 weeks, from birth to 6 weeks. The filtered Na load increased fivefold but urine Na excretion decreased from 3.4 to 0.1% of the filtered Na load. The efficiency of Na reabsorption increased 8% in the proximal tubule compared with 66% in the distal tubule. Because greater than 90% of Na reabsorption always occurred proximally, the smaller percentage increase in efficiency of the proximal tubule contributed as much as the larger percentage increase in efficiency of the distal tubule to the postnatal improvement in renal Na conservation.

The Development of a Second Generation of Controlled Diffusion Airfoils for Multistage Compressors

The evolution of Controlled Diffusion Airfoils is traced from inception of the theoretical design model to demonstration of significant performance gains at engine operating conditions in a multistage compressor rig. The proven aerodynamic benefits and versatility of first-generation Controlled Diffusion Airfoil blade elements are extended to the endwall flow region using an Integrated Core/Endwall Vortex design model to produce a new full-span optimized second-generation Controlled Diffusion design. Highlighted are the essential roles of extensive cascade, low-speed, large-scale, and high Mach number compressor rig testing in developing and substantiating the second-generation Controlled Diffusion technology resulting in a 1.5 percent increase in efficiency and 30 percent increase in surge-free operation relative to first-generation Controlled Diffusion Airfoils.

4483392 Air to air heat exchanger : Edward Korsmo, Eugene R Boedecker assigned to Xchanger Inc

In this work, an experimental investigation into the effects, in terms of energy, of employing a dedicated mechanical subcooling cycle with a residential 1.5 ton simple vapor compression refrigeration system is presented. A comparative analysis of the experimental cycle performance is conducted with and without the dedicated subcooler cycle when the room temperature is kept between 18 and 22 °C. This is done in order to ascertain the percentage increase in efficiency due to use of a dedicated subcooling loop. R22 is employed as the refrigerant in the main cycle whereas R12 is flowing in the dedicated subcooling cycle. The experimental outcomes indicate that the load carrying capacity of the evaporator increased by approximately 0.5 kW when R22 was subcooled, in the main cycle, by 5–8 °C. It was also noted that, by using the subcooling, the second-law efficiency of the cycle increased by an average of 21%. Furthermore, the general trend indicated that this percentage increase is inversely proportional to the ambient temperature variation. The experimental work proves that dedicated subcooling can be used for increasing cooling capacity and efficiency.

Multistage Decoding of Frequency-Hopped FSK System

A recent paper described an unproved decoding scheme for a frequency-hopped multilevel FSK system. We examined this multiple access communication system for possible application in satellite communication and mobile radio telephony. The new decoder, using the known algebraic structure of the users' addresses, reduces mutual interference and achieves a 50 to 60 percent increase in efficiency over conventional decoding. The present paper shows how additional decoding can further increase the efficiency, bringing it very close (within half a percent) to optimum. The scheme makes use of information derived while decoding the messages of other users and thus is especially attractive for the base station, where such information is readily available and does not require a significant increase in complexify. Compared to conventional decoding, the new scheme more than doubles the number of simultaneous users.

On efficient majority logic decodable codes

A particular shortening technique is applied to majority logic decodable codes of length 2^{t} . The shortening technique yields new efficient codes of lengths n = 2^{p} , where p is a prime, e.g., a (128,70) code with d_{maj} = 16 . For moderately long code lengths (e.g., n = 2^{11} or 2^{13}) , a 20-25 percent increase in efficiency can be achieved over the best previously known majority logic decodable codes. The new technique also yields some efficient codes for lengths n = 2^{m} where m is a composite number, for example, a (512,316) code with d_{maj} = 32 code which has 42 more information bits than the previously most efficient majority logic decodable code.