scholarly journals Hybrid System Converting Solar Energy Into Electric Energy

2021 ◽  
Vol 7 (9) ◽  
pp. 12-26
Author(s):  
Yu. Ismanov ◽  
N. Niyazov ◽  
N. Dzhamankyzov
Keyword(s):  
Mathematical Model ◽  
Temperature Gradient ◽  
Hybrid System ◽  
Thermoelectric Generator ◽  
Thermal Contact Resistance ◽  
Thermal Contact ◽  
Electrical Energy ◽  
Operating Conditions ◽  
Photovoltaic Module ◽  
Optimal Operating

The article discusses a mathematical model of a hybrid system that combines photovoltaic and thermoelectric methods for converting concentrated solar energy into electrical energy. The specified mathematical model makes it possible to determine the temperatures of the photovoltaic module, as well as the temperature of the electrodes of the thermoelectric generator module. Optimal operating conditions have been determined for the hybrid system, taking into account the thermal contact resistance at the hot and cold sides of the thermoelectric generator. The simulation proceeded from the fact that only part of the absorbed solar radiation is converted into electricity due to the photoelectric effect, some part is lost due to radiation and convection from the upper surface of the photovoltaic module into the environment, and the rest is transferred to a thermoelectric generator connected to the lower part. photovoltaic module. A thermoelectric generator converts some of the thermal energy it receives from the photovoltaic module into electricity through the Seebeck effect, but most of it goes to the cooling system. The conversion of heat into electrical energy was based on the well-known Seebeck and Peltier effects. Along with these effects, such effects were taken into account as the formation of Joule heat due to the presence of electric current in the thermoelectric generator, Fourier thermal conductivity, as a consequence of the appearance of a temperature gradient in the transitions of a thermoelectric generator and Thomson heat, which arises both due to the presence of a temperature gradient, and electric current. The resulting model of the hybrid system makes it possible to study the effect of changing the temperature difference between the hot and cold electrodes of the thermoelectric generator and the resistance of the external circuit on the performance of the hybrid system. The model also allows the determination of the optimal operating conditions for the hybrid system, taking into account the thermal contact resistance on the hot and cold sides of the thermoelectric generator.

Effects of Heat Accumulation on the Thermodynamic and Economic Performance of CHP

2001 ◽  
Author(s):  
Jozef Portacha ◽  
Adam Smyk ◽  
Alicja Zielinska ◽  
Jerzy K. Fiszdon
Keyword(s):  
Mathematical Model ◽  
Numerical Method ◽  
Economic Performance ◽  
Electrical Energy ◽  
Operating Conditions ◽  
Electricity Production ◽  
Heat Accumulation ◽  
Heat Accumulator ◽  
The Mathematical Model

Abstract Heat accumulation in cogenerating plants allows increased electricity production during highest demand period. It also causes change of the overall electricity production. Changes in cogeneration coefficient follow the same trend. This paper examines the effect on the average cogeneration factor caused by adding the heat accumulator to the existing CHP. Variation of this coefficient influences the plant economics, since electrical energy is most expensive during the peak hours. In the model presented the operating conditions vary due to variations in the surroundings temperature and due to cyclical operation of the heat accumulator. Assumptions made, the mathematical model, and numerical method used are also presented.

A Scheme to Assist in the Evaluation of Tenter Frame Dryer Performance

1979 ◽  
Vol 101 (1) ◽  
pp. 80-84 ◽  
Author(s):  
W. F. Beckwith ◽  
J. N. Beard
Keyword(s):  
Mathematical Model ◽  
Differential Equations ◽  
Operating Conditions ◽  
Temperature Profiles ◽  
Simulation Studies ◽  
Drying Process ◽  
Optimal Operating

One of the textile industry’s largest consumers of energy is the tenter frame dryer. To assist the industry in operating these dryers efficiently, a mathematical model which simulates the drying process and a scheme to solve for the parameters in the differential equations of the model have been developed and are presented in this paper. Temperature profiles predicted from the model are compared with profiles measured on commercial dryers. Also dryer simulation studies to elucidate optimal operating conditions are discussed.

scholarly journals Hybrid carbon thermal interface materials for thermoelectric generator devices

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Seok-Hwan Chung ◽  
Jong Tae Kim ◽  
Dong Hwan Kim
Keyword(s):  
Contact Resistance ◽  
Output Power ◽  
Thermoelectric Generator ◽  
Thermal Contact Resistance ◽  
Thermal Contact ◽  
Applied Pressure ◽  
Thermal Interface Materials ◽  
Thermal Interface ◽  
Interface Materials ◽  
Hybrid Carbon

Abstract Thermal interface materials (TIMs) are extensively used in electronic devices as efficient heat transfer materials. We fabricated all-carbon TIMs by hybridizing single-wall carbon nanotubes (SWCNTs) with graphite and demonstrated their performance by applying them to a thermoelectric generator (TEG) device. The hybrid carbon TIM exhibited maximum thermal conductivity when the SWCNT content was near 10 wt%. The TIM thermal contact resistance measured by a home-made calorimeter setup was 2.19 × 10−4 m2K/W, which did not vary with temperature but decreased with applied pressure. Post-treatment of the TIM with a silane coupling agent further reduced the TIM thermal contact resistance by 30%. When the TIM was placed between a TEG device and a copper heat reservoir, the TEG output power increased with the temperature difference across the TEG and applied pressure. Moreover, the post-treatment of the TIM enhanced the output power of the TEG device by up to 18.5%. This work provides a simple and effective pathway towards a carbon-based TIM that can be applied to a high temperature TEG.

Extrapolation Errors in Thermal Contact Resistance Measurements

1975 ◽  
Vol 97 (2) ◽  
pp. 305-307 ◽  
Author(s):  
T. R. Thomas
Keyword(s):  
Temperature Gradient ◽  
Contact Resistance ◽  
Thermal Contact Resistance ◽  
Thermal Contact ◽  
Temperature Drop ◽  
Interface Temperature ◽  
Better Than

In the classic split-bar determination of thermal contact resistance the temperature drop across the interface is estimated by extrapolating a temperature gradient measured remotely. It is shown that this can give rise to substantial errors which cannot greatly be reduced by increasing the number of measurements. It is suggested that due to extrapolation errors few interface temperature drops have ever been determined to better than 1/2 °K, and that this may account for some of the discrepancies between published contact resistances, particularly those measured at high loads.

Modeling and Estimating Simulated Burn Depth Using the Perfusion and Thermal Resistance Probe

2013 ◽  
Vol 7 (3) ◽  
Author(s):  
Abdusalam Al-Khwaji ◽  
Brian Vick ◽  
Tom Diller
Keyword(s):  
Mathematical Model ◽  
Heat Flux ◽  
Parameter Estimation ◽  
Thermal Resistance ◽  
Contact Resistance ◽  
Core Temperature ◽  
Thermal Contact Resistance ◽  
Thermal Contact ◽  
Blood Perfusion ◽  
Thermal Event

A new thermal perfusion probe operates by imposing a thermal event on the tissue surface and directly measuring the temperature and heat flux response of the tissue with a small sensor. The thermal event is created by convectively cooling the surface with a small group of impinging jets using room temperature air. The hypothesis of this research is that this sensor can be used to provide practical burn characterization of depth and severity by determining the thickness of nonperfused tissue. To demonstrate this capability the measurement system was tested with a phantom tissue that simulates the blood perfusion of tissue. Different thicknesses of plastic were used at the surface to mimic layers of dead tissue. A mathematical model developed by Alkhwaji et al. (2012, “New Mathematical Model to Estimate Tissue Blood Perfusion, Thermal Contact Resistance and Core Temperature,” ASME J. Biomech. Eng., 134, p. 081004) is used to determine the effective values of blood perfusion, core temperature, and thermal resistance from the thermal measurements. The analytical solutions of the Pennes bioheat equation using the Green's function method is coupled with an efficient parameter estimation procedure to minimize the error between measured and analytical heat flux. Seven different thicknesses of plastic were used along with three different flow rates of perfusate to simulate burned skin of the phantom perfusion system. The resulting values of thermal resistance are a combination of the plastic resistance and thermal contact resistance between the sensor and plastic surface. Even with the uncertainty of sensor placement on the surface, the complete set of thermal resistance measurements correlate well with the layer thickness. The values are also nearly independent of the flow rate of the perfusate, which shows that the parameter estimation can successfully separate these two parameters. These results with simulated burns show the value of this minimally invasive technique to measure the thickness of nonperfused layers. This will encourage further work with this method on actual tissue burns.

scholarly journals Design and development of a process-economic mathematical model of a lupine hydrolysis unit

2019 ◽  
Vol 292 ◽  
pp. 01028
Author(s):  
Jiří Pecha ◽  
Lubomír Šánek ◽  
Miloš Jelínek ◽  
Jakub Husár ◽  
Karel Kolomazník
Keyword(s):  
Mathematical Model ◽  
Amino Acids ◽  
Computer Simulation ◽  
Production Process ◽  
Chemical Reaction ◽  
Process Modelling ◽  
Operating Conditions ◽  
Optimal Operating ◽  
Human Diet ◽  
High Level

Lupine is considered as a source of protein with a high level of valuable amino acids, what can have in a human diet significant impact on the prevention of various diseases. This paper deals with the process modelling and computer simulation of the lupine flour hydrolysis, particularly focusing on calculations and comparisons of different process variants. Suggested process-economic mathematical model of the production process is a very effective tool for achieving optimal operating conditions under which the specific costs of preparing the final hydrolyzed product are minimal. Simultaneously, the proposed mathematical model of the production node of the hydrolysis unit includes the key processes for the preparation of the resulting hydrolyzate, i.e. the chemical reaction itself, filtration of the reaction mixture and concentration of the filtrate, which is the final desired product – the lupine hydrolysate.

Assessment of Thermoelectric Module With Nanofluid Heat Exchanger

2007 ◽  
Author(s):  
A. G. Agwu Nnanna ◽  
William Rutherford ◽  
Wessam Elomar ◽  
Brian Sankowski
Keyword(s):  
Heat Exchanger ◽  
Temperature Gradient ◽  
Contact Resistance ◽  
Thermal Contact Resistance ◽  
Thermal Contact ◽  
Thermoelectric Module ◽  
Thermal Response ◽  
Deionized Water ◽  
Cold Side ◽  
Thermal Paste

For applications such as cooling of electronic devices, it is a common practice to sandwich the thermoelectric module between an integrated chip and a heat exchanger, with the cold side of the module attached to the chip. This configuration results thermal contact resistances in series between the chip, module, and heat exchanger. In this paper, an appraisal of thermal augmentation of thermoelectric module using nanofluid-based heat exchanger is presented. The system under consideration uses commercially available thermoelectric module, 27nm Al2O3 - H2O nanofluid, and a heat source to replicate the chip. The volume fraction of nanofluid is varied between 0 to 2%. At optimum input current conditions, experimental simulations were performed to measure the transient and steady-state thermal response of the module to imposed isoflux conditions. Data collected from the nanofluid-based exchanger is compared with that of deionized water. Results show that there exist a lag-time in thermal response between the module and the heat exchanger. This is attributed to thermal contact resistance between the two components. A comparison of nanofluid and deionized water data reveals that the temperature difference between the hot- and cold-side, ΔT = Th − Tc ≈ 0, is almost zero for nanofluid whereas ΔT > 0 for water. When ΔT ≈ 0, the contribution of Fourier effect to the overall heating is approximately zero hence enhancing the module cooling capacity. Experimental evidence further shows that temperature gradient across the thermal paste that bonds the chip and heat exchanger is much lower for the nanofluid than for deionized water. Low temperature gradient results in low resistance to the flow of heat across the thermal paste. The average thermal contact resistance, R = ΔT/Q, is 0.18 and 0.12 °C/W, respectively for the deionized-water and nanofluid. For the range of optimum current, 1.2 ≤ current ≤ 4.1Amp, considered in this study, the COP ranges between 1.96 and 0.68.

EXPERIMENTAL STUDIES OF CAR PROPERTIES ON A PHYSICAL MODEL

2019 ◽  
pp. 10-16
Author(s):  
Oleksii Timkov ◽  
Dmytro Yashchenko ◽  
Volodymyr Bosenko
Keyword(s):  
Mathematical Model ◽  
Remote Control ◽  
Physical Model ◽  
Model Experiment ◽  
Experimental Studies ◽  
Electrical Energy ◽  
Short Term ◽  
Motor Current ◽  
Memory Card ◽  
The Mathematical Model

The article deals with the development of a physical model of a car equipped with measuring, recording and remote control equipment for experimental study of car properties. A detailed description of the design of the physical model and of the electronic modules used is given, links to application libraries and the code of the first part of the program for remote control of the model are given. Atmega microcontroller on the Arduino Uno platform was used to manage the model and register the parameters. When moving the car on the memory card saved such parameters as speed, voltage on the motor, current on the motor, the angle of the steered wheel, acceleration along three coordinate axes are recorded. Use of more powerful microcontrollers will allow to expand the list of the registered parameters of movement of the car. It is possible to measure the forces acting on the elements of the car and other parameters. In the future, it is planned to develop a mathematical model of motion of the car and check its adequacy in conducting experimental studies on maneuverability on the physical model. In addition, it is possible to conduct studies of stability and consumption of electrical energy. The physical model allows to quickly change geometric dimensions and mass parameters. In the study of highway trains, this approach will allow to investigate the various layout schemes of highway trains in the short term. It is possible to make two-axle road trains and saddle towed trains, three-way hitched trains of different layout. The results obtained will allow us to improve not only the mathematical model, but also the experimental physical model, and move on to further study the properties of hybrid road trains with an active trailer link. This approach allows to reduce material and time costs when researching the properties of cars and road trains. Keywords: car, physical model, experiment, road trains, sensor, remote control, maneuverability, stability.

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