scholarly journals Study of Operation of the Thermoelectric Generators Dedicated to Wood-Fired Stoves

Energies ◽  
2021 ◽  
Vol 14 (19) ◽  
pp. 6264
Author(s):  
Krzysztof Sornek
Keyword(s):  
Waste Heat ◽  
Cooling System ◽  
Combustion Process ◽  
Thermoelectric Module ◽  
Operating Conditions ◽  
Thermoelectric Generators ◽  
Thermoelectric Modules ◽  
Gas Channel ◽  
Cogeneration System ◽  
Electronic Load

Thermoelectric generators are devices that harvest waste heat and convert it into useful power. They are considered as an additional power source in the domestic sector, but they can also be installed in off-grid objects. In addition, they are a promising solution for regions where there is a lack of electricity. Since biomass heating and cooking stoves are widely used, it is very appropriate to integrate thermoelectric generators with wood-fired stoves. This paper shows the experimental analysis of a micro-cogeneration system equipped with a wood-fired stove and two prototypical constructions of thermoelectric generators dedicated to mounting on the flue gas channel. The first version was equipped with one basic thermoelectric module and used to test various cooling methods, while the second construction integrated four basic thermoelectric modules and a water-cooling system. During the tests conducted, the electricity generated in the thermoelectric generators was measured by the electronic load, which allowed the simulation of various operating conditions. The results obtained confirm the possibility of using thermoelectric generators to generate power from waste heat resulting from the wood-fired stove. The maximum power obtained during the discussed combustion process was 15.4 W (if this value occurred during the entire main phase, the energy generated would be at a level of approximately 30 Wh), while the heat transferred to the water was ca. 750 Wh. Furthermore, two specially introduced factors (CPC and CPTC) allowed the comparison of developed generators, and the conclusion was drawn that both developed constructions were characterized by higher CPC values compared to available units in the market. By introducing thermoelectric modules characterized by higher performance, a higher amount of electricity generated may be provided, and sufficient levels of current and voltage may be achieved.

scholarly journals Effect of Different Operating Conditions on Performance of Commercial Low-Temperature Thermoelectric Modules

2019 ◽  
Vol 9 (2) ◽  
pp. 1781-1791
Keyword(s):  
Low Temperature ◽  
Conversion Efficiency ◽  
Power Output ◽  
Waste Heat ◽  
Thermoelectric Module ◽  
Operating Conditions ◽  
Maximum Power ◽  
Thermoelectric Modules ◽  
Temperature Range ◽  
Maximum Power Output

In the field of waste heat recovery, thermoelectric generators (TEG) are used to convert waste heat to electric power. This system attracts the attention of researchers to make it more and more efficient. The performance of thermoelectric module (TEM) plays a crucial role for thermoelectric system. Appropriate selection of thermoelectric module is one of the important criteria for enhancing the power output and conversion efficiency of thermoelectric generator. In this work, the effect of various operating conditions on performance of thermoelectric modules was experimentally investigated. Three commercial bismuth telluride (Bi2Te3 ) thermoelectric modules (TEM1, TEM2, and TEM3) were experimentally tested to find the best performance module for low-temperature waste heat. The open-circuit voltage, power output, and conversion efficiency were measured at various operating conditions. Different operating parameters such as water mass flow rate, heater voltage, hot and cold side temperature of thermoelectric module, and external load resistance were considered for this work. An electric heater was used as a heat source and water used as a cooling fluid at heat sink side. It was observed that the TEM1 shows maximum power output of 0.31, 0.71 and 1.25W, for temperature ranges of 80-100, 100-150, and 150-200 oC respectively. TEM3 achieved maximum power output 0.81W for temperature range of 100-150 oC. TEM1, TEM2 and TEM3 have the maximum conversion efficiency of 1.37, 0.60, and 1.64 % respectively. The TEM2 having less power output and conversion efficiency for temperature range of 80-200 oC compare to TEM1 and TEM3. However, the TEM1 is more appropriate for temperature range of 80-200 oC and the TEM3 is also suitable for the temperature range of 80-150 oC.

scholarly journals Thermodynamic Assessment on the Integration of Thermo-Electric Modules in a Wood Fireplace

2019 ◽  
Vol 29 (4) ◽  
pp. 218-235
Author(s):  
Andrea Baldini ◽  
Luca Cerofolini ◽  
Daniele Fiaschi ◽  
Giampaolo Manfrida ◽  
Lorenzo Talluri
Keyword(s):  
Heat Transfer ◽  
Thermodynamic Assessment ◽  
New Technologies ◽  
Waste Heat ◽  
Cooling System ◽  
Combustion Process ◽  
Design Solution ◽  
Thermoelectric Generators ◽  
Thermo Electric ◽  
Wasted Heat

Abstract The growing demand for electricity produced from renewable sources and the development of new technologies for the combustion of biomass, arose a growing interest on the possible coupling of thermoelectric modules with stove-fireplaces. The current thermoelectric generators have a solid structure, do not produce noise, do not require maintenance and can be used for the recovery of waste heat or excess, at the same time they hold a very low conversion efficiency and they need an adequate cooling system. Nevertheless, they still hold a cost, which is still too high to make them attractive. Nonetheless, if the modules are applied to a heat source which otherwise would be wasted, the attractiveness of the solution certainly rises. In this study, a thermodynamic analysis of a stove-fireplace is presented, considering both combustion process and the flame – walls heat transfer of the. A design solution for a concentrator device to funnel the wasted heat from the fireplace to the thermo-electric modules is also presented.

Thermoelectric Modules For High Temperature Waste Heat

2005 ◽  
Vol 886 ◽  
Author(s):  
Ryoji Funahashi ◽  
Toshiyuki Mihara ◽  
Masashi Mikami ◽  
Saori Urata
Keyword(s):  
Room Temperature ◽  
Open Circuit Voltage ◽  
Waste Heat ◽  
Thermal Strain ◽  
Thermoelectric Module ◽  
Internal Resistance ◽  
Open Circuit ◽  
Cold Side ◽  
Adhesive Material ◽  
Thermoelectric Modules

ABSTRACTA new adhesive material has been developed in order to obtain practically usable thermoelectric modules composed of oxide thermoelectric legs. The thermoelectric module composed of 8-pair oxide legs has been fabricated. Both hot- and cold-sides of the module were covered by alumina plates. Open circuit voltage VO and maximum power Pmax reach 0.38 V and 0.30 W, respectively at 803 K of a hot-side temperature TH and 362 K of a temperature differential ΔT between TH and cold-side temperature TC. Generating power was repeated 11 times at 873-993 K of TH and at 200-290 K of ΔT. The module was cooled down to room temperature after each generation. At third measurement internal resistance RI of the module increased by 30 %. This is due to destruction of junctions because of thermal strain. No deterioration, however, was observed in thermoelectric properties for the oxide legs.

Thermo-economic Assessment, and Multi-objective Optimization of an Innovatively Designed District Cooling System in Saudi Arabia

2021 ◽  
pp. 1-29
Author(s):  
Ali Alsagri
Keyword(s):  
Saudi Arabia ◽  
Waste Heat ◽  
Cooling System ◽  
Economic Assessment ◽  
Optimization Techniques ◽  
Operating Conditions ◽  
Peak Shaving ◽  
Assessment Index ◽  
Economic Analyses

Abstract The experience of leading countries in distributed energy systems (e.g., Scandinavian countries) shows that district cooling systems are highly beneficial techno-economic-environmentally by facilitating the use of waste heat resources, solar energy, etc., for cold supply at large scales. This study proposes the optimal development of a novel district cooling design utilizing the exhaust waste heat of an energy plant in a case study in Saudi Arabia. The optimal configuration of the hybrid system, the sizing of its components, and operating conditions of them are found using multiobjective optimization techniques based on the genetic algorithm method and a creative performance assessment index. Then, the feasibility of this optimized proposal is investigated through comprehensive thermodynamic and economic analyses. The results show that a district cooling system can surely cope with the harsh climate condition of the case study and provide the required interior comfort conditions. The energy and exergy efficiencies of the system can be as high as 62% and 53% using an absorption chiller utilizing a power plant's waste heat along with a storage tank for peak shaving. The levelized cost of cooling of the system can be 28 USD/MWh, by which the payback period will be only 8 years.

scholarly journals Theoretical Study for an Adsorption Refrigerator

2021 ◽  
Vol 8 (1) ◽  
Author(s):  
Abdulghani M. Ramadan
Keyword(s):  
Adsorption Capacity ◽  
Waste Heat ◽  
Cooling System ◽  
Operating Conditions ◽  
Equilibrium Adsorption ◽  
Design Parameters ◽  
Low Grade ◽  
Equilibrium Pressure ◽  
Study Results ◽  
Equilibrium Adsorption Capacity

Adsorption cooling technology is one of the effective means to convert low grade thermal energy in to effective cooling, which improves energy efficiency and lowers environmental pollution. The main objective of this study is to investigate the thermal performance of an adsorption refrigerator theoretically. The working adsorbent/adsorbate pair used is Granular Activated Carbon, GAC/R134a pa*ir. The effect of different design parameters and operating conditions on the system performance is studied and interpreted.Some assumptions and approximations are also considered. A computer program is written using Matlab. Results show that the equilibrium adsorption capacity is highly affected by the driving temperature and equilibrium pressure. Increasing equilibrium pressure leads to a corresponding increase in the equilibrium adsorption capacity whereas it is value is decreased as the driving temperature increases. Moreover, increasing the driving and evaporator temperatures raise the values of the Specific Cooling Effect (SCE) andCoefficient of Performance (COP). The maximum values of SCE and COP are 60 KJ/kg and 0.4 corresponding to driving and evaporator temperatures of 100 oC and 20 oC respectively. However, increasing the condenser temperature leads to a remarked decrease in SCE and COP of the cooling system. SCE and COP values are 32 KJ/kg and 0.22 at driving and condenser temperatures of 100 oC and 40 oC respectively. When comparing the present study results with literature, there is a good agreement in general. It is clear that the adsorption cooling system can be driven effectively by low grade heat sources such as, solar energy, waste heat energy, geothermal energy…etc.

Optimization of a Thermoelectric Air Conditioning Systems

2013 ◽  
Vol 336 ◽  
pp. 111-120
Author(s):  
Jamir Machado da Silva ◽  
Renan Eduardo da Silva ◽  
José Rui Camargo ◽  
Ederaldo Godoy Junior
Keyword(s):  
Cooling System ◽  
Thermoelectric Module ◽  
Electrical Current ◽  
Coefficient Of Performance ◽  
Thermoelectric Cooling ◽  
Thermoelectric Modules ◽  
Air Inlet ◽  
The One ◽  
Air Conditioning Systems ◽  
Cooling Air

This paper studies the optimization of a thermoelectric cooling system of air. Based on both results obtained experimentally and from a mathematical model, we evaluated the available features of thermoelectric modules and parameters subject to optimization. In the thermoelectric cooling air process based on the effect discovered by Jean Peltier Charles Athanase in 1834, when an electrical current is conducted through a semiconductor junction between two materials with different properties, heat is absorbed and dissipated. Thermoelectric modules are made of semiconductor materials and sealed between two plates. According to the shape of the plate, the current flow cools the one hand and the other is heated. The most important parameters to evaluate the efficiency of the thermoelectric cooling is the coefficient of performance, the rate of heat transfer and temperature difference between the maximum possible to the cold and hot sides of the thermoelectric module. In this evaluation were used thermoelectric modules and heat sinks, commercially available temperature sensors and a software for obtaining, storing and comparing the data. The prototype auxiliary allows the surface temperatures of thermoelectric modules of the hot and cold sides, the air inlet and outlet temperatures of the heat sink sides of the hot and cold air flow, the voltage and the electrical current to be applied to the modules. A simulation is performed using two air flows at a speed controlled for the hot and cold sides of the module and a set of tests for various modules, i.e. one, two, three and four coupled in parallel. Using this system, the performance data is analyzed making it possible to check the power, voltage and electrical current to maximize the coefficient of performance of the system.

Waste Heat Recovery in Heavy-Duty Diesel Engines: A Thermodynamic Analysis of Waste Heat Availability for Implementation of Energy Recovery Systems Based Upon the Organic Rankine Cycle

2012 ◽  
Author(s):  
A. Cozzolini ◽  
M. C. Besch ◽  
D. Littera ◽  
H. Kappanna ◽  
P. Bonsack ◽  
...  
Keyword(s):  
Waste Heat Recovery ◽  
Waste Heat ◽  
Cooling System ◽  
Combustion Process ◽  
Organic Rankine Cycle ◽  
Rankine Cycle ◽  
Exhaust Gas ◽  
Engine Efficiency ◽  
Waste Energy ◽  
Heavy Duty Diesel

In the past decade automotive industries have focused on the development of new technologies to improve the overall engine efficiency and lower emissions in order to satisfy the always more stringent emission standards introduced all around the world. Technical progress has primarily focused on two aspects; the optimization of the air-fuel mixture in the combustion chamber as well as the combustion process itself, leading to simultaneous improvements in both, efficiency (lowering fuel consumption for same power output) and emissions levels which ultimately result from the optimized combustion process. Although engine technology has made significant progress, even modern Diesel combustion engines do not exceed a maximum efficiency of approximately 40%. Hence, around 60% of the available energy carried by the fuel and entering the combustion chamber is dissipated as heat to the environment. The next steps in engine optimization will see the integration of waste heat recovery systems (WHRS) to increase the overall energy efficiency of the propulsion system by means of recovering parts of the waste heat generated during normal engine operation. The presented was aimed at analyzing the availability as well as the quality of heat to be used in WHRS for the case of heavy-duty Diesel (HDD) engines employed in Class-8 tractors, which are suitable candidates for optimization via WHRS implementation as their engines spend most of their time operating at quasi steady state conditions, such as highway cruise. Three different primary energy sources have been considered: exhaust gas recirculation (EGR) cooling system, engine cooling system and exhaust gas stream. Experimental data has been gathered at West Virginia University’s Engine and Emissions Research Laboratory (EERL) facility in order to quantify individual heat flows in a model year (MY) 2004 Mack® MP7-355E HDD engine operated over the 13 modes of the European Stationary Cycle (ESC). Analysis based on second law efficiency underlined that not the whole amount of waste heat can be successfully used for recovery purposes and that heat sources which offer a large amount of waste energy reveal to be inappropriate for recovery purposes in case of low operating temperature. Time integral analysis revealed that engine modes which appear to offer high recovery potential in terms of waste power may not be suitable engine operating conditions when the analysis is performed in terms of waste energy, depending on the particular engine cycle. Finally a simple thermodynamic model of a micro power unit running on an Organic Rankine Cycle (ORC) has been used to assess the theoretical improvement in engine efficiency during steady state operations based on a second law efficiency analysis approach.

Feasibility of Thermoelectric Waste Heat Recovery in Large Scale Systems

2008 ◽  
Author(s):  
Jacob LaManna ◽  
David Ortiz ◽  
Mark Livelli ◽  
Samuel Haas ◽  
Chinedu Chikwem ◽  
...  
Keyword(s):  
Heat Recovery ◽  
Waste Heat Recovery ◽  
Large Scale ◽  
Waste Heat ◽  
Thermoelectric Module ◽  
Operating Conditions ◽  
Heat Transfer Analysis ◽  
Electrical Performance ◽  
Design Parameters ◽  
Waste Heat Recovery System

With the growing emphasis on energy efficiency because of environmental, political, and economic reasons and the fact there has been significant advances in thermoelectric materials, there is a renewed interest in using thermoelectrics for waste heat recovery. A mathematical model of a thermoelectric power system is developed from a heat transfer analysis of a waste heat recovery system. The model is validated by altering design parameters of a small prototype thermoelectric system that converts heat into electricity. A heated air stream is produced using an exhaust simulation test stand and provides the waste heat source for the prototype. The prototype is designed to be able to change several system parameters such as different heat sinks, thermoelectric module counts, and module configurations to better validate the developed model. The model does predict the electrical performance with typical accuracy of 30% error from the prototype over a range of configurations and operating conditions. A feasibility study using the validated model was used to determine under what conditions this technology will become economically viable, such as remote power generation with 20 year payback.

Optimal Arrangement of Thermoelectric Modules for Recovering the Waste Heat of Damavand Power Plant using Mutable Smart Bee and Neuro-Fuzzy System

2013 ◽  
Vol 4 (4) ◽  
pp. 46-62 ◽  
Author(s):  
Pendar Samadian ◽  
Ahmad Mozaffari ◽  
Ali Goudarzi ◽  
Alireza Rezania ◽  
Lasse Rosendahl
Keyword(s):  
Power Plant ◽  
Fuzzy Inference ◽  
Waste Heat ◽  
Thermoelectric Module ◽  
Maintenance Cost ◽  
Optimal Arrangement ◽  
Inference System ◽  
Thermoelectric Modules ◽  
Neuro Fuzzy ◽  
Temperature Rate

In current research, the authors intend to find the optimal arrangement of planar thermoelectric modules to maximize the generated electricity and minimize the maintenance cost of a power system called Damavand power plant. Optimal arrangement is done by mounting a number of thermoelectric modules within the condenser in order to recover the waste heat of the thermal system. For this purpose, firstly, an adaptive neuro fuzzy inference system (ANFIS) is utilized to model the generated power of thermoelectric module and the corresponding maintenance cost. Thereafter, Gambit and Fluent softwares are applied to evaluate the temperature rate through the length of thermoelectric component. Given the derived information, the authors use a recent spotlighted metaheuristic called mutable smart bee algorithm (MSBA) to optimally arrange the thermoelectric modulus for recovering the waste heat of Damavand power plant. Based on the obtained numerical results, it is proven that the proposed frame work is completely capable of finding a practical arrangement of thermoelectric cells within the entry of condenser component.

scholarly journals Thermal Characteristics Investigation of the Internal Combustion Engine Cooling-Combustion System Using Thermal Boundary Dynamic Coupling Method and Experimental Verification

Energies ◽  
2018 ◽  
Vol 11 (8) ◽  
pp. 2127 ◽  
Author(s):  
Junhong Zhang ◽  
Zhexuan Xu ◽  
Jiewei Lin ◽  
Zefeng Lin ◽  
Jingchao Wang ◽  
...  
Keyword(s):  
Cooling System ◽  
Combustion Engine ◽  
Coupling Effect ◽  
Combustion Process ◽  
Thermal Characteristics ◽  
Engine Performance ◽  
Operating Conditions ◽  
Coolant Flow ◽  
Coupled Modeling ◽  
Engine Cooling

The engine cooling system must be able to match up with the stable operating conditions so as to guarantee the engine performance. On the working cycle level, however, the dynamic thermo-state of engines has not been considered in the cooling strategy. Besides, the frequent over-cooling boiling inside the gallery changes the cooling capacity constantly. It is necessary to study the coupling effect caused by the interaction of cooling flow and in-cylinder combustion so as to provide details of the dynamic control of cooling systems. To this end, this study develops a coupled modeling scheme of the cooling process considering the interaction of combustion and coolant flow. The global reaction mechanism is used for the combustion process and the multiphase flow method is employed to simulate the coolant flow considering the wall boiling and the interphase forces. The two sub-models exchange information of in-cylinder temperature, heat transfer coefficient, and wall temperature to achieve the coupled computation. The proposed modeling process is verified through the measured diesel engine power, in-cylinder pressure, and fire surface temperature of cylinder head. Then the effects of different cooling conditions on the cyclic engine performances are analyzed and discussed.

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