Performance Analysis of a Combination System of Concentrating Photovoltaic/Thermal Collector and Thermoelectric Generators

2014 ◽  
Vol 136 (4) ◽  
Author(s):  
Xinqiang Xu ◽  
Siyi Zhou ◽  
Mark M. Meyers ◽  
Bahgat G. Sammakia ◽  
Bruce T. Murray
Keyword(s):  
Hybrid System ◽  
Seebeck Effect ◽  
Electrical Performance ◽  
Peltier Effect ◽  
Accurate Estimation ◽  
Transfer Model ◽  
Cooling Channel ◽  
Cell Array ◽  
Matching Problem ◽  
Te Modules

Thermoelectric (TE) modules utilize available temperature differences to generate electricity by the Seebeck effect. The current study investigates the merits of employing thermoelectrics to harvest additional electric energy instead of just cooling concentrating photovoltaic (CPV) modules by heat sinks (heat extractors). One of the attractive options to convert solar energy into electricity efficiently is to laminate TE modules between CPV modules and heat extractors to form a CPV-TE/thermal (CPV-TE/T) hybrid system. In order to perform an accurate estimation of the additional electrical energy harvested, a coupled-field model is developed to calculate the electrical performance of TE devices, which incorporates a rigorous interfacial energy balance including the Seebeck effect, the Peltier effect, and Joule heating, and results in better predictions of the conversion capability. Moreover, a 3D multiphysics computational model for the HCPV-TE/T water collector system consisting of a solar concentrator, 10 serially connected GaAs/Ge photovoltaic (PV) cells, 300 couples of bismuth telluride TE modules, and a cooling channel with heat-recovery capability, is implemented by using the commercial FE–tool Comsol Multiphysics®. A conjugate heat transfer model is used, assuming laminar flow through the cooling channel. The performance and efficiencies of the hybrid system are analyzed. As compared with the traditional photovoltaic/thermal (PV/T) system, a comparable thermal efficiency and a higher 8% increase of the electrical efficiency can be observed through the PV-TE hybrid system. Additionally, with the identical convective surface area and cooling flow rate in both configurations, the PV-TE/T hybrid system yields higher PV cell temperatures but more uniform temperature distributions across the cell array, which thus eliminates the current matching problem; however, the higher cell temperatures lower the PV module's fatigue life, which has become one of the biggest challenges in the PV-TE hybrid system.

Performance Analysis of a Combination System of Concentrating PV/T Collector and TEGs

2013 ◽  
Author(s):  
Xinqiang Xu ◽  
Siyi Zhou ◽  
Mark Meyers ◽  
Bahgat G. Sammakia ◽  
Bruce Murray
Keyword(s):  
Hybrid System ◽  
Seebeck Effect ◽  
Electrical Performance ◽  
Peltier Effect ◽  
Accurate Estimation ◽  
Transfer Model ◽  
Cooling Channel ◽  
Cell Array ◽  
Matching Problem ◽  
Te Modules

Thermoelectric modules utilize available temperature differences to generate electricity by the Seebeck effect. The current study investigates the merits of employing thermoelectrics to harvest additional electric energy instead of just cooling concentrating photovoltaic (CPV) modules by heat sinks (heat extractors). One of the attractive options to convert solar energy into electricity efficiently is to laminate TE modules between CPV modules and heat extractors to form a CPV-TE/thermal hybrid system. In order to perform an accurate estimation of the additional electrical energy harvested, a coupled field model is developed to calculate the electrical performance of TE devices, which incorporates a rigorous interfacial energy balance including the Seebeck effect, the Peltier effect, and Joule heating, and results in better predictions of the conversion capability. Moreover, a 3D multiphysics computational model for the hybrid concentrating PV-TE/thermal (CPV-TE/T) water collector system consisting of a solar concentrator, 10 serially-connected GaAs/Ge PV cells, 300 couples of bismuth telluride TE modules, and a cooling channel with heat-recovery capability, is implemented by using the commercial FE–tool COMSOL™. A conjugate heat transfer model is used, assuming laminar flow through the cooling channel. The performance and efficiencies of the hybrid system are analyzed. As compared with the traditional PV/T system, a comparable thermal efficiency and a higher 8% increase of the electrical efficiency can be observed through the PV-TE hybrid system. Additionally, with the identical convective surface area and cooling flow rate in both configurations, the PV-TE/T hybrid system yields higher PV cell temperatures but more uniform temperature distributions across the cell array, which thus eliminates the current matching problem; however, the higher cell temperatures lower the PV module’s fatigue life, which has become one of the biggest challenges in the PV-TE hybrid system.

Thermal Therapy Protocols for Benign Prostatic Hyperplasia

2007 ◽  
Author(s):  
Daniel Chinn ◽  
Elvis Nditafon ◽  
Alvin Yew ◽  
Chandrasekhar Thamire
Keyword(s):  
Benign Prostatic Hyperplasia ◽  
Thermal Damage ◽  
Prostatic Hyperplasia ◽  
Operating Conditions ◽  
Thermal Therapy ◽  
Bioheat Transfer ◽  
Surrounding Tissue ◽  
Accurate Estimation ◽  
Transfer Model ◽  
Porous Media Model

Thermal therapy for treatment of benign prostatic hyperplasia (BPH) is becoming increasingly popular due to the minimally invasive nature of the treatment. Successful management of such therapy requires accurate estimation of thermal dosage. The purpose of this study is to provide correlations for the thermal damage caused by ultrasound, microwave, and infrared devices under a range of operating conditions. A boundary-fitting finite difference method is used to examine the heat transfer in the prostate gland and surrounding tissue. The Pennes bioheat transfer model and a porous media model were utilized to calculate temperature histories. Necrosis zones were determined using published necrosis data for prostatic tissue and cells. Thermal damage correlations for the three different hyperthermia sources along with sample temperature contours and necrosis zones are presented. Results indicate that the applicator power level and heating time are the most important parameters in achieving the desired necrosis zones, while coolant parameters strongly affect the temperatures of the sensitive urethra and serve as constraints for protocol parameters. Out of the three sources evaluated, ultrasound modality appears to be the most capable of causing necrosis in the target zones, with least damage to the surrounding healthy tissues.

Laser Seebeck Effect Imaging (SEI) and Peltier Effect Imaging (PEI): complementary investigation methods.

2003 ◽  
Vol 43 (9-11) ◽  
pp. 1609-1613 ◽  
Author(s):  
Stefan Dilhaire ◽  
Amine Salhi ◽  
Stéphane Grauby ◽  
Wilfrid Claeys
Keyword(s):  
Seebeck Effect ◽  
Peltier Effect ◽  
Investigation Methods

scholarly journals Segmented Thermoelectric Generator under Variable Pulsed Heat Input Power

Entropy ◽  
2019 ◽  
Vol 21 (10) ◽  
pp. 929 ◽  
Author(s):  
Pablo Ruiz-Ortega ◽  
Miguel Olivares-Robles ◽  
Olao Enciso-Montes de Oca
Keyword(s):  
Heat Input ◽  
Figure Of Merit ◽  
Thermoelectric Generator ◽  
Temperature Drop ◽  
Transient State ◽  
Input Power ◽  
Electrical Performance ◽  
Maximum Efficiency ◽  
Peltier Effect ◽  
Finite Differences Method

In this paper, we consider the transient state behavior of a segmented thermoelectric generator (STEG) exposed to a variable heat input power on the hot side while the transfer of heat on the cold side is by natural convection. Numerical analysis is used to calculate the power generation of the system. A one-dimensional STEG model, which includes Joule heating, the Peltier effect with constant properties of materials, is considered and governing equations are solved using the finite differences method. The transient analysis of this model is typical for energy harvesting applications. A novel design methodology, formulated on the ratio of the figure of merit of the thermoelectric materials, is developed including segmentation on the legs of the thermoelectric generator, which does not consider previous studies. In our approach, the figure of merit is an advantageous parameter to analyze its impact on thermal and electrical efficiency. The transient state of the thermoelectric generator is analyzed, considering two and three heat input sources. We obtain the temperature profiles, voltage generation, and efficiency of the STEG under pulsed heat input power. The results showed that the temperature drop along the semiconductor elements was more considerable when three pulses were applied, and when the thermal conductivity in the first segment was higher than that of the second segment. Furthermore, we show that the generated voltage and the maximum efficiency in the system occur when the value of the figure of merit in the first segment, which is in contact with the temperature source, is lower than the figure of merit for the second thermoelectric segment of the leg. The model investigated in this paper offers an essential guide on the thermal and electrical performance behavior of the system under transient conditions, which are present in many variable thermal phenomena such as solar radiation and the normalized driving cycles of an automotive thermoelectric generator.

scholarly journals Assessment of thermal and electrical performance of BIPV façades using simplified simulations

2021 ◽  
Vol 2042 (1) ◽  
pp. 012081
Author(s):  
Romain Schindelholz ◽  
Mohammad Rahiminejad ◽  
Arnab Chatterjee ◽  
Dolaana Khovalyg
Keyword(s):  
Energy Use ◽  
Thermal Inertia ◽  
Visual Programming ◽  
Electrical Performance ◽  
Transfer Model ◽  
Complex Flow ◽  
Building Site ◽  
Electrical Efficiency ◽  
3D Cad ◽  
Wall Structures

Abstract Building integrated photovoltaic (BIPV) facades are a solution to consider when it comes to electricity generation on the building site. One of the main challenges attributes to this technology is finding the best trade-off between the electrical efficiency of BIPVs and the energy use of the building. This study aims to identify a scenario that yields the optimized results for electrical and thermal performance in a test building. Among the scenarios, the original wooden cladding in the test building is either replaced with PV panels or the PV modules are added to the existing facade. Rhinoceros 3D CAD software and its visual programming plugin Grasshopper are used to perform various simulations for both east-oriented and west-oriented façades with low and high thermal inertia wall structures. Although a complex flow phenomenon behind BIPVs is simplified in the 3D heat transfer model, relatively reliable results are obtained using the chosen simulation tool. It is observed that the east-faced BIPV facade in the test building has higher electrical efficiency. This could be attributed to the lower inertia of the east wall that allows easier propagation of heat through the structure.

Rotordynamic Characterization of Labyrinth Seals in Steam Turbines: Effects of Thermal and Mechanical Loads

2018 ◽  
Author(s):  
Filippo Cangioli ◽  
Steven Chatterton ◽  
Paolo Pennacchi ◽  
Leonardo Nettis ◽  
Lorenzo Ciuchicchi ◽  
...  
Keyword(s):  
Flow Model ◽  
High Pressures ◽  
Labyrinth Seal ◽  
Bulk Flow ◽  
Critical Conditions ◽  
Accurate Estimation ◽  
Transfer Model ◽  
Steam Turbines ◽  
Labyrinth Seals ◽  
The Stability

Over the last few decades, the increasing demand on efficiency and performance for steam turbines has resulted in OEMs operating machines near critical conditions of their structural and thermal capabilities. Consequently, a more accurate estimation of the dynamic behavior of the machine has become mandatory as well as the stability assessment. Steam turbines are subjected to high temperatures, high pressures and centrifugal forces that could change the nominal geometry, especially the clearance profile in correspondence of the sealing components, occasionally generating a convergent or divergent annulus. In this paper, a new thermo-elasto bulk-flow model for labyrinth seals has been introduced. The model includes the bulk-flow model for estimating the dynamic coefficients, heat transfer model for evaluating the temperature distribution in the rotating and stationary parts and structural-mechanics model for calculating the radial growth. By considering a staggered labyrinth seal installed in the balancing drum of a steam turbine, different inlet pre-swirl ratios, as well as the stability of the seal are investigated in this paper. The model can be extremely useful for the dynamic characterisation of a wide class of labyrinth seals considering the effect of the surrounding environment on the rotordynamic coefficient prediction.

Fabrication and Performance Simulation of Microscale Thermoelectric Modules Made with Bi2Te3-Based Alloys

2011 ◽  
Vol 483 ◽  
pp. 75-77 ◽  
Author(s):  
Da Wei Liu ◽  
Jing Feng Li
Keyword(s):  
Peltier Effect ◽  
Micro Electro Mechanical Systems ◽  
Thermoelectric Modules ◽  
Plasma Sintering ◽  
Potential Applications ◽  
In Series ◽  
Spark Plasma ◽  
And Performance ◽  
Te Modules ◽  
Mechanical Cutting

Micro or nano scale thermoelectric (TE) modules have received increasing attention because of their potential applications as energy supplyingand thermal managing components in microelectronic devices and micro-electro-mechanical systems (MEMS). In the present work, microscale thermoelectric modules are fabricated by combining mechanical cutting and photolithograph processes from nano-sized silicon carbide (SiC) particles reinforced Bi2Te3-based materials (Bi2Te3 for n type, and Bi0.5Sb1.5Te3 for p type) prepared by spark plasma sintering (SPS). The fabricated modules have 28 pairs of thermoelectric legs in an area of 3×3 mm2, and each of them is 200×400 µm2 in cross section and 600 µm in length, which is connected in series by Ni-Cu electrodes made with photolithograph patterning and magnetron sputtering. The thermoelectric performances of a p-n couple are simulated with the finite element method (FEM) under a thermal-electrical coupled multi-physics field for both electronic cooling (Peltier effect) and thermoelectric energy generation (Seebeck effect) working mold.

Investigation of the off-diagonal Seebeck effect and Peltier effect on textured YBa2Cu3O7−δ

1997 ◽  
Vol 282-287 ◽  
pp. 1247-1248
Author(s):  
Z.H. He ◽  
F.Q. Zhong ◽  
Y.Y. Luo ◽  
M. Wu ◽  
W. Gavalek ◽  
...  
Keyword(s):  
Seebeck Effect ◽  
Peltier Effect
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