A review on the cooling of energy conversion and storage systems using thermoelectric modules

Exploitation of sustainable energy sources requires the use of unique conversion and storage systems,such as solar panels,batteries,fuel cells,and electronic equipment.Thermal load management of these energy conversion and storage systems is one of their challenges and concerns.In this article,the thermal management of these systems using thermoelectric modules is reviewed.The results show that by choosing the right option to remove heat from the hot side of the thermoelectric modules,it will be a suitable local cooling,and the thermoelectric modules increase the power and lifespan of the system by reducing the spot temperature.Thermoelectric modules were effective in reducing panel temperature.They increase the time to reach a temperature above 50℃ in batteries by 3 to 4 times.Also,in their integration with fuel cells,they increase the power density of the fuel cell.

Performance improvement in stepped solar still modified by sponge layer

In this paper,the experimental investigation on the performance improvement of conventional stepped solar still is conducted.The steps are covered by the porous material to improve the performance of the conventional device and increase the evaporation rate.All the parameters,including the temperature on the glass surface,the water temperature inside the evaporation zone,and the amount of water produced in both conventional and modified stepped solar stills are measured and compared.The efficiency of two devices and their exergy efficiency have been calculated.Finally,the economic analysis of both devices has been done to check the economic feasibility of the modified device.The amount of freshwater generated during one day was 2244.4 and 3076.2 mL/m^(2),respectively for the conventional and modified stepped solar stills.As a result,the amount of water produced in one day by modified stepped solar still is 35.5% more than the conventional one.Also,the costs for the conventional and modified stepped solar stills have been calculated as 0.0359 and 0.029$/(L·m^(-2)),respectively.

An advanced turbulator with blades and semi-conical section for heat transfer improvement in a helical double tube heat exchanger

In present work,a helical double tube heat exchanger is proposed in which an advanced turbulator with blades,semi-conical part,and two holes is inserted in inner section.Two geometrical parameters,including angle of turbulator’s blades(θ) and number of turbulator’s blades(N),are considered.Results indicated that firstly,the best thermal stratification is achieved at θ=180°.Furthermore,at the lowest studied mass flow rate(m = 8 × 10^(-3) kg/s),heat transfer coefficient of turbulator with blade angle of 180° is 130.77%,25%,and 36.36% higher than cases including without turbulator,with turbulator with blade angle of θ =240°,and θ =360°,respectively.Moreover,case with N=12 showed the highest overall performance.At the highest studied mass flow rate(m = 5.842 × 10^(-2) kg/s),heat transfer coefficient for case with N=12 is up to 54.76%,27.45%,and 6.56% higher than cases including without turbulator,with turbulator with N=6,and with turbulator with N=9,respectively.

Analytical approximation of heat and mass transfer in MHD non-Newtonian nanofluid flow over a stretching sheet with convective surface boundary conditions

The paper provides an analytical investigation, homotopy analysis method （HAM）, of the heat and mass transfer for magnetohydrodynamic Oldroyd-B nanofluid flow over a stretching sheet in the presence of convective boundary condition. The PDE governing equations, which consist of equations of continuity, momentum, energy and nanoparti- cles, are converted to ordinary differential equations using similarity transformations. The current HAM solution demonstrates very good correlation with those of the pre- viously published studies in the special cases. The influences of different flow physical parameters such as the Deborah numbers in terms of relaxation and retardation times （/3i, /32）, magnetic parameter （M）, Prandtl number （Pr）, Brownian motion parameter （Nb）, thermophoresis parameter （Nt）, Lewis number （Le）, and Biot number （Bi） on he fluid velocity component （f＇（η））, temperature distribution （θ（η）） and concentration φ（η）） as well as the local Nusselt number （Nux/Rex ） and the local Sherwood number （Shx/Re1/2 ） are discussed in detail.