scholarly journals Simplified thermoelectric generator (TEG) with heatsinks modeling and simulation using Matlab and Simulink based-on dimensional analysis

AIMS Energy ◽  
2021 ◽  
Vol 9 (6) ◽  
pp. 1213-1240
Author(s):  
Nganyang Paul Bayendang ◽  
◽  
Mohamed Tariq Kahn ◽  
Vipin Balyan
Keyword(s):  
Dimensional Analysis ◽  
Heat Exchangers ◽  
Alternative Energy ◽  
Thermoelectric Generator ◽  
Dimensionless Parameter ◽  
Dimensionless Temperature ◽  
Energy Sustainability ◽  
Practical Design ◽  
Analytical Formulas ◽  
Direct Calculations

<abstract> <p>Energy sustainability is becoming paramount today with the focus being on renewable and alternative energy. This manuscript therefore embarks on clean alternative energy rooted in thermoelectricity with focus on thermoelectric generator (TEG). However, a TEG do practically needs heat-exchangers or heatsinks to properly and reliably work but heatsinks present another problem—thermal resistance, which affects a TEG power output and efficiency and thus, must be addressed. Consequently, we investigate a TEG with heatsinks model based-on dimensional analysis using Matlab and Simulink. Our research has three unique contributions. Firstly, we derived the analytical formulas for direct calculations of TEG dimensionless hot and cold sides temperature and by introducing and applying a new dimensionless parameter, the dimensionless temperature difference (<italic>DT<sub>s</sub></italic>). Secondly, we simplified further the new TEG dimensionless hot and cold sides temperature analytical formulas to obtain simpler and simplest forms. Thirdly, we implemented a TEG with heatsinks Matlab/Simulink theoretical model, that employs the simplified dimensional analysis, in which a TEG with heatsinks parameters of interest can be simulated to variously determine the analytical, numerical and graphical results with various optimal options to opt for, before doing a practical design.</p> </abstract>

Heat Sink Design for Thermoelectric Generation in Spindle Unit

2013 ◽  
Vol 365-366 ◽  
pp. 285-288
Author(s):  
Sheng Li ◽  
Qing Hui Zeng ◽  
Xin Hua Yao ◽  
Jian Zhong Fu
Keyword(s):  
Heat Sink ◽  
Alternative Energy ◽  
Thermoelectric Generator ◽  
Rotation Speed ◽  
Waste Heat ◽  
Heat Sinks ◽  
Thermoelectric Generation ◽  
Promising Alternative ◽  
Spindle Unit ◽  
Thermoelectric Energy Harvesting

Thermoelectric energy harvesting is emerging as a promising alternative energy source to drive wireless sensors in mechanical, civil, and aerospace engineering systems. Typically, the waste heat from spindle units of machine tools creates obvious potential for thermoelectric generation. The structure of heat sinks on a thermoelectric generator has a great effect on the output voltage of the thermoelectric generator due to the temperature difference between hot and cold sides induced by heat transfer, so several typical structures of heat sinks are studied under different rotation speed of the spindle. According to the simulation study, the thermal resistance of heat sinks was presented. In the experiment, the output voltages of a thermoelectric generator were measured under different rotation speed with different structures of heat sinks. Experiment and simulation shows that the two pipes structure of the heat sink can help the generator to produce more power.

scholarly journals Dimensional analysis of a landscape evolution model with incision threshold

2020 ◽  
Vol 8 (2) ◽  
pp. 505-526
Author(s):  
Nikos Theodoratos ◽  
James W. Kirchner
Keyword(s):  
Dimensional Analysis ◽  
Governing Equation ◽  
Dimensionless Parameter ◽  
Landscape Evolution ◽  
Initial Conditions ◽  
Uplift Rate ◽  
Stream Power ◽  
Linear Diffusion ◽  
Scaling Properties

Abstract. The ability of erosional processes to incise into a topographic surface can be limited by a threshold. Incision thresholds affect the topography of landscapes and their scaling properties and can introduce nonlinear relations between climate and erosion with notable implications for long-term landscape evolution. Despite their potential importance, incision thresholds are often omitted from the incision terms of landscape evolution models (LEMs) to simplify analyses. Here, we present theoretical and numerical results from a dimensional analysis of an LEM that includes terms for threshold-limited stream-power incision, linear diffusion, and uplift. The LEM is parameterized by four parameters (incision coefficient and incision threshold, diffusion coefficient, and uplift rate). The LEM's governing equation can be greatly simplified by recasting it in a dimensionless form that depends on only one dimensionless parameter, the incision-threshold number Nθ. This dimensionless parameter is defined in terms of the incision threshold, the incision coefficient, and the uplift rate, and it quantifies the reduction in the rate of incision due to the incision threshold relative to the uplift rate. Being the only parameter in the dimensionless governing equation, Nθ is the only parameter controlling the evolution of landscapes in this LEM. Thus, landscapes with the same Nθ will evolve geometrically similarly, provided that their boundary and initial conditions are normalized according to appropriate scaling relationships, as we demonstrate using a numerical experiment. In contrast, landscapes with different Nθ values will be influenced to different degrees by their incision thresholds. Using results from a second set of numerical simulations, each with a different incision-threshold number, we qualitatively illustrate how the value of Nθ influences the topography, and we show that relief scales with the quantity Nθ+1 (except where the incision threshold reduces the rate of incision to zero).

scholarly journals Assessment of the Feasibility of Implementing Shower Heat Exchangers in Residential Buildings Based on Users’ Energy Saving Preferences

Energies ◽  
2021 ◽  
Vol 14 (17) ◽  
pp. 5547
Author(s):  
Sabina Kordana-Obuch ◽  
Mariusz Starzec ◽  
Daniel Słyś
Keyword(s):  
Heat Exchangers ◽  
Alternative Energy ◽  
Energy Savings ◽  
Residential Buildings ◽  
Hot Water ◽  
Energy Sources ◽  
Domestic Hot Water ◽  
Alternative Energy Sources ◽  
Save Energy ◽  
Willingness To Use

In Poland, domestic hot water is heated mainly using fossil fuel energy sources. Such an approach results in the depletion of natural resources, pollution of the atmosphere and, consequently, irreversible changes to the climate. In response to this problem, this research identified the factors that most determine energy savings for heating water in residential buildings, as well as those that affect the choice of an alternative energy source. Additionally, the possibility of implementing shower heat exchangers in existing and newly built residential buildings was assessed, as well as society’s willingness to use such devices. The research was carried out on a sample of 462 inhabitants of the Podkarpackie Voivodeship (Poland). A questionnaire survey was used as a tool. The conducted research has shown that the perspective of environmental protection is not a sufficient motivator to save energy for heating domestic hot water. It is necessary to implement appropriate programs aimed at informing the public about the possibilities offered by the use of alternative energy sources and co-financing the purchase of appropriate devices. In the case of drain water heat recovery systems, a significant problem is also the need to develop new, highly effective designs of shower heat exchangers which can be installed under the floor linear shower drain or on the horizontal shower waste pipe.

Temperature Relations in Shell and Tube Exchangers Having One-Pass Split-Flow Shells

1964 ◽  
Vol 86 (3) ◽  
pp. 408-415 ◽  
Author(s):  
Luis Jaw
Keyword(s):  
Correction Factor ◽  
Infinite Number ◽  
Heat Exchangers ◽  
Correction Factors ◽  
Split Flow ◽  
Mathematical Expressions ◽  
Dimensionless Groups ◽  
Practical Design ◽  
Shell And Tube ◽  
Peak Value

Mean temperature difference correction factors are presented in the usual dimensionless groups of P and R for shell and tube heat exchangers where the shell fluid is divided into two streams entering at the center of the shell. Mathematical expressions have been derived for the thermal effectiveness P for both two and four tube passes in terms of UA/wc and wc/WC designated as R. The expressions for the split-flow exchangers with one and with an infinite number of tube passes are also presented. The analysis is further extended so that the correction factor F for split-flow exchangers of four tube passes and an infinite number of tube passes may be used for any even number of tube passes within a practical design range. There is very little difference between correction factors of values above 0.8, for split-flow exchangers with two, four, and infinite number of tube passes, and the conventional 1–2 shell and tube exchanger. An interesting result is noted that for each value of R there is a peak value of P.

Two-Dimensional Analysis of Conduction-Controlled Rewetting With Precursory Cooling

1976 ◽  
Vol 98 (3) ◽  
pp. 407-413 ◽  
Author(s):  
S. S. Dua ◽  
C. L. Tien
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Coefficient ◽  
Transfer Coefficient ◽  
Dimensional Analysis ◽  
Vertical Surface ◽  
Dimensionless Temperature ◽  
Two Dimensional ◽  
Dimensional Solution ◽  
One Dimensional ◽  
The One

This paper presents a two-dimensional analysis of the effect of precursory cooling on conduction-controlled rewetting of a vertical surface, whose initial temperature is higher than the sputtering temperature. Precursory cooling refers to the cooling caused by the droplet-vapor mixture in the region immediately ahead of the wet front, and is described mathematically by two dimensionless constants which characterize its magnitude and the region of influence. The physical model developed to account for precursory cooling consists of an infinitely extended vertical surface with the dry region ahead of the wet front characterized by an exponentially decaying heat flux and the wet region behind the moving film-front associated with a constant heat transfer coefficient. Apart from the two dimensionless constants describing the extent of precursory cooling, the physical problem is characterized by three dimensionless groups: the Peclet number or the dimensionless wetting velocity, the Biot number and a dimensionless temperature. Limiting solutions for large and small Peclet numbers have been obtained utilizing the Wiener-Hopf technique coupled with appropriate kernel substitutions. A semiempirical matching relation is then devised for the entire range of Peclet numbers. Existing experimental data with variable flow rates at atmospheric pressure are very closely correlated by the present model. Finally a comparison is drawn between the one-dimensional limit of the present analysis and the corresponding one-dimensional solution obtained by treating the dry region ahead of the wet front characterized by an exponentially decaying heat transfer coefficient.

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