Heat Transfer of a Stack of Low-Thermal-Conductivity Plates in Cyclic Heat Exchange with Cold and Hot Media

2021 ◽  
Vol 94 (2) ◽  
pp. 286-297
Author(s):  
Yu. A. Kirsanov ◽  
D. V. Makarushkin ◽  
A. Yu. Kirsanov ◽  
A. E. Yudakhin
Keyword(s):  
Heat Transfer ◽  
Thermal Conductivity ◽  
Heat Exchange ◽  
Low Thermal Conductivity ◽  
Cyclic Heat

Latent Heat Storage: Container Geometry, Enhancement Techniques, and Applications—A Review

2019 ◽  
Vol 141 (5) ◽  
Author(s):  
S. Arunachalam
Keyword(s):  
Heat Transfer ◽  
Thermal Conductivity ◽  
Energy Storage ◽  
Phase Change ◽  
Latent Heat ◽  
Thermal Energy ◽  
Heat Exchangers ◽  
Phase Change Materials ◽  
Heat Storage ◽  
Low Thermal Conductivity

Energy storage helps in waste management, environmental protection, saving of fossil fuels, cost effectiveness, and sustainable growth. Phase change material (PCM) is a substance which undergoes simultaneous melting and solidification at certain temperature and pressure and can thereby absorb and release thermal energy. Phase change materials are also called thermal batteries which have the ability to store large amount of heat at fixed temperature. Effective integration of the latent heat thermal energy storage system with solar thermal collectors depends on heat storage materials and heat exchangers. The practical limitation of the latent heat thermal energy system for successful implementation in various applications is mainly from its low thermal conductivity. Low thermal conductivity leads to low heat transfer coefficient, and thereby, the phase change process is prolonged which signifies the requirement of heat transfer enhancement techniques. Typically, for salt hydrates and organic PCMs, the thermal conductivity range varies between 0.4–0.7 W/m K and 0.15–0.3 W/m K which increases the thermal resistance within phase change materials during operation, seriously affecting efficiency and thermal response. This paper reviews the different geometry of commercial heat exchangers that can be used to address the problem of low thermal conductivity, like use of fins, additives with high thermal conductivity materials like metal strips, microencapsulated PCM, composite PCM, porous metals, porous metal foam matrix, carbon nanofibers and nanotubes, etc. Finally, different solar thermal applications and potential PCMs for low-temperature thermal energy storage were also discussed.

Heat exchange apparatus of low thermal conductivity plastics

1969 ◽  
Vol 5 (8) ◽  
pp. 650-651
Author(s):  
S. M. Lukomskii ◽  
D. F. Kagan ◽  
M. Ya. Nemlikher
Keyword(s):  
Thermal Conductivity ◽  
Heat Exchange ◽  
Low Thermal Conductivity ◽  
Exchange Apparatus

scholarly journals Heat Exchange Evaluation at Thermo-Adhezion Method of Extraction of Diamond Raw from Kimberlite Ore

2018 ◽  
Vol 8 (1) ◽  
pp. 23
Author(s):  
P. P. Sharin ◽  
M. P. Lebedev ◽  
G. M. Nikitin ◽  
G. G. Vinokurov ◽  
M. P. Akimova
Keyword(s):  
Heat Transfer ◽  
Thermal Conductivity ◽  
Heat Exchange ◽  
High Selectivity ◽  
Waste Rock ◽  
The Difference ◽  
Method Of Extraction

In the work thermo-adhesion a method of selecting and extracting the grains of diamond from a mixture of related minerals is developed. The study presents estimates of the heat transfer of the proposed scheme extraction based on the difference between the thermal conductivity of diamond and related minerals. The high selectivity thermo-adhesion selection and extraction of diamonds with the division concentrate on useful component and waste rock is shown.

scholarly journals DETERMINING OF PARAMETERS OF HEAT EXCHANGE FOR VAPORIZATION OF THE MIXED REFRIGERANT ON THE HIGH THERMAL CONDUCTIVITY SINTERED POWDER CAPILLARY-POROUS COATINGS

2018 ◽  
Vol 61 (1) ◽  
pp. 70-79 ◽  
Author(s):  
A. V. Ovsyannik ◽  
E. N. Makeeva
Keyword(s):  
Heat Transfer ◽  
Thermal Conductivity ◽  
Heat Exchange ◽  
Experimental Studies ◽  
Nucleate Boiling ◽  
High Thermal Conductivity ◽  
Porous Coating ◽  
Transfer Coefficients ◽  
Porous Coatings ◽  
Wide Range

The results of experimental research of heat exchange under the nucleate boiling of refrigerants R404a, R407c and R410a on the tubes with capillary-porous coating are presented. Experimental studies were carried out with the aid of an experimental installation in conditions of a large volume at pressures of saturation pн = 0.9–1.4 MPa and densities of the heat flux q = 5–35 kW/m2. For the first time the criterion equation for the calculation of the intensity of heat transfer during evaporation of ozone safe refrigerants on surfaces with high thermal conductivity sintered capillary-porous coating was obtained. Experimental data are summarized satisfactorily in a wide range of parameters of the porous layer, i.e. the pressure (pн = 0.9–1.4 MPa) and heat loads (q = 5–35 kW/m2). The ratio makes us possible to calculate the heat transfer coefficients within ±20 %. The dependence can be used in engineering calculations of the characteristics of the heat exchangers of the evaporative type. The coefficient of heat transfer during boiling of refrigerants on the investigated surfaces with the sintered capillary-porous coating, 4 times higher than on a smooth one and 1.5 times higher than on the finned surface, that allows us to come to a conclusion about the advantage of porous coatings. Boiling in capillary-porous coating leads to a decrease in weight and size of the installations due to the heat exchange intensification and the size of the tubes smaller as compared to the size of the finned ones.

Experimental Investigation on the Thermal Insulation Properties of Eic-Cellulose

2014 ◽  
Vol 554 ◽  
pp. 322-326 ◽  
Author(s):  
Wuryanti Sri ◽  
Suhardjo Poertadji ◽  
Bambang Soegijono ◽  
Nasution Henry
Keyword(s):  
Heat Transfer ◽  
Thermal Conductivity ◽  
Experimental Investigation ◽  
Thermal Insulation ◽  
Cellulose Fibers ◽  
Extraction Process ◽  
Thermal Capacity ◽  
Insulation Material ◽  
Low Thermal Conductivity ◽  
Thermal Conductivities

The material with low thermal conductivity means it has a high insulating capability for reducing heat transfer. One of materials for insulation is cellulose. This study presents a insulation material of cellulose made from reeds imperata cylindrical type with the extraction process. The extraction of cellulose fibers to form a sheet by adding 3.5% Na-CMC (Sodium Cellulose Carboksil Metyl). The process of forming the sheet uses blender for 30 minutes, 45 minutes, and 60 minutes. Furthermore, each mixture are put into the oven with temperature of 40°C for 36 hours. There are three parameters will be investigated, i.e. thermal conductivity, density and thermal capacity. The results showed that the lowest and the highest of thermal conductivities were 0.22 W/m K and a maximum 0.36 W/m K, respectively.

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