scholarly journals Influence of Operating Parameters on the Performance of an Adsorption Solar Refrigeration Machine

2021 ◽  
Author(s):  
adnane ghrici ◽  
MEA GHERNAOUT ◽  
Mohammed BENRAMDANE
Keyword(s):  
Thermodynamic Parameters ◽  
Air Conditioning ◽  
Heating Temperature ◽  
Adsorption Refrigeration ◽  
Different Types ◽  
Maximum Heating Temperature ◽  
Low Performance ◽  
Maximum Heating ◽  
Solar Refrigeration ◽  
Refrigeration Machine

Abstract Renewable energies including solar energy requirements for refrigeration and air conditioning are increasingly gaining interest due to the refrigerants friendly to the environment. However, it was found that these technologies have some limitations like the low performance and their high cost. This paper proposes a comparative study of a solar adsorption refrigeration machine. The study consists in determining the optimal thermodynamic parameters of operation as well as their influences on the performance of the system. This is based on a thermodynamic model using different types of adsorbent / adsorbate pairs. The main parameters considered in this study are: temperature of generation, evaporation, maximum heating temperature, condensation pressure as well as the type of the pair used: activated carbon / methanol and zeolite / water. Simulations for different thermodynamic parameters show that the COP is very sensitive to the generation and evaporation temperatures as well as the maximum heating temperature, on the other hand it was slightly influenced by the condensation pressure. The results obtained have shown that the AC / methanol pair is more profitable than the zeolite / water pair.

scholarly journals Effect of Operating Temperatures and Working Pairs on Performance of Solar Adsorption Cooling System

2021 ◽  
Vol 39 (4) ◽  
pp. 1280-1286
Author(s):  
Ghrici Adenane ◽  
Benramdane Mohammed ◽  
Ghernaout Mea
Keyword(s):  
Thermodynamic Parameters ◽  
Cooling System ◽  
Heating Temperature ◽  
Adsorption Refrigeration ◽  
Different Types ◽  
Maximum Heating Temperature ◽  
Low Performance ◽  
Adsorption Cooling System ◽  
Maximum Heating ◽  
Refrigeration Machine

Renewable energies including solar energy requirements for refrigeration and air conditioning are increasingly gaining interest due to the refrigerants friendly to the environment. However, it was found that these technologies have some limitations like the low performance and their high cost. This paper proposes a comparative study of a solar adsorption refrigeration machine. The study consists in determining the influence of thermodynamic parameters of operation on the performance of the system. This is based on a thermodynamic model using different types of adsorbent / adsorbate pairs. The main parameters considered in this study are: temperature of generation, evaporation, maximum heating temperature, condensation pressure as well as the type of the pair used: activated carbon / methanol and zeolite / water. Simulations for different thermodynamic parameters show that the COP is very sensitive to the generation and evaporation temperatures as well as the maximum heating temperature, on the other hand it was slightly influenced by the condensation pressure. The results obtained have shown that the AC / methanol pair is more profitable than the zeolite / water pair.

STRUCTURAL TRANSFORMATIONS OF CARBON NANOMATERIAL UNDER INFLUENCE OF HIGH ENERGY LASER IRRADIATION

2019 ◽  
Vol 62 (1-2) ◽  
pp. 171-180
Author(s):  
P.E. Pavlyuchenko ◽  
G.M. Seropyan ◽  
M.V. Trenikhin ◽  
V.A. Drozdov
Keyword(s):  
Heating Temperature ◽  
High Energy ◽  
Carbon Nanomaterial ◽  
Turbostratic Carbon ◽  
Graphene Layers ◽  
Nanostructured Particles ◽  
Maximum Heating Temperature ◽  
Energy Laser ◽  
High Energy Laser ◽  
Maximum Heating

Laser pulse irradiation of the globular turbostratic carbon material in various conditions was carried out in this work. It was investigated by TEM that the formation of nanostructured particles (nanocapsules) during irradiation at 1064 nm wavelength occurs with power density of 108 W/cm2, and it’s rise up to 1011 W/cm2 leads to increase the degree of ordering of the obtained structures. It is shown that irradiation of the initial globules with pulses at 532 nm wavelength allows to reduce the interplanar spacing of graphene layers from 0,410 nm to 0,346 nm in the formed nanocapsules. The dependence of the maximum heating temperature of nanoparticles on the energy density on the laser spot was analyzed. The influence of the heating temperature of the carbon nanomaterial on structure and morphology was stated.

scholarly journals Nanostructured SiGe:Sb solid solutions with improved thermoelectric figure of merit

2020 ◽  
Author(s):  
Mikhail Vladimirovich Dorokhin ◽  
Polina Borisovna Demina ◽  
Irina Viktorovna Erofeeva ◽  
Yuri Mikhailovich Kuznetsov ◽  
Anton Vladimirovich Zdoroveyshchev ◽  
...  
Keyword(s):  
Solid State ◽  
Figure Of Merit ◽  
Heating Temperature ◽  
Thermoelectric Figure Of Merit ◽  
Thermoelectric Figure ◽  
Plasma Sintering ◽  
Solid State Sintering ◽  
Maximum Heating Temperature ◽  
Spark Plasma ◽  
Maximum Heating

Abstract Thermoelectric Si 0,65 Ge 0,35 Sb δ materials have been fabricated by spark plasma sintering of Ge-Si-Sb powder mixture. The electronic properties of Si 0,65 Ge 0,35 Sb δ were found to be dependent on the uniformity of mixing of the components, which in turn is determined by the maximum heating temperature during solid-state sintering. Provided the concentration of donor Sb impurity is optimized the thermoelectric figure of merit for the investigated structures can be as high as 0.628 at the temperature of 490 °С, the latter value is comparable with world-known analogues obtained for Si 1- x Ge x P δ .

Поверхностная закалка колесной стали высокоэнтальпийной плазменной струей// Journal of Technical and Natural Sciences 1(10), 2019/ OEAPS Inc.(Open European Academy of Public Sciences); Chief Editor Vitaly Yakovlev- Berlin, Germany. 26.01.2019: OEAPS Inc., 2019. - pp. 8-26.

2019 ◽  
Author(s):  
Серик Кажимович Бийжанов ◽  
Амангельды Токешович Канаев
Keyword(s):  
Plasma Treatment ◽  
Heat Affected Zone ◽  
Heating Temperature ◽  
Chief Editor ◽  
Natural Sciences ◽  
Austenite Decomposition ◽  
Surface Plasma ◽  
European Academy ◽  
Maximum Heating Temperature ◽  
Maximum Heating

В статье дается подробное описание процесса поверхностной плазменной обработки тяжело нагруженных стальных деталей. Для решения вопроса о типе структур, возникающих в зоне термического влияния и, следовательно, об их свойствах, определяются скорости охлаждения в каждом микрообъеме, с последующим сопоставлением с термокинетическими кривыми распада аустенита при определенной концентрации аустенита и максимальной температуре нагрева.The article provides a detailed description of the process of surface plasma treatment of heavily loaded steel parts. To solve the problem of the type of structures arising in the heat-affected zone and, therefore, their properties, the cooling rates in each microvolume are determined, followed by comparison with the thermokinetic austenite decomposition curves at a certain austenite concentration and maximum heating temperature.

INVESTIGATION OF THE MOISTURE BINDING FORMS IN PLANT RAW MATERIALS AND THERMAL CHARACTERISTICS DETERMINATION

2020 ◽  
Vol 2020 (4) ◽  
pp. 186-192
Author(s):  
Tojiniso Raxmanova ◽  
◽  
Shaxnoza Sultanova ◽  
Jasur Safarov ◽  
Esra Capanoglu
Keyword(s):  
Raw Materials ◽  
Heating Temperature ◽  
Thermal Characteristics ◽  
Rate Of Change ◽  
Plant Materials ◽  
Plant Raw Materials ◽  
Binding Forms ◽  
Maximum Heating Temperature ◽  
Dog Rose ◽  
Maximum Heating

In this article, the forms of moisture connection and the thermal characteristics of plant materials are studied. Rosehip and hawthorn fruits were chosen as the object of research. In the heat analyzer, a decrease in the mass of the product and an increase in temperature were found when the temperature was controlled in a certain gas environment. The curves of the dependence of the dog rose and hawthorn samples on the mass and temperature are given. DTA-1/10 galvanometer sensitivity; sensitivity of the DTG-1/5 galvanometer; the maximum heating temperature is 300° С and the rate of change of the furnace heating temperature is 3° С / min. The temperature features of the process of thermolysis of plant products have been studied. As a result of the study, the initial temperature, the highest and the final temperature of endothermic action were determined. The thermophysical properties of rose hips and hawthorn fruits were studied on the basis of experiments and the results are reflected in the tables below. Coefficients of thermal conductivity and specific heat of mass in the temperature range 20-80 ºC are given.

COMPARATIVE ANALYSIS OF THE FOAM GLASS GRAVEL TYPES EXPERIMENTALLY PRODUCED BY MICROWAVE IRRADIATION

2020 ◽  
Vol 26 (3) ◽  
pp. 58-68
Author(s):  
FELICIA COSMULESCU ◽  
LUCIAN PAUNESCU ◽  
MARIUS FLORIN DRAGOESCU ◽  
SORIN MIRCEA AXINTE
Keyword(s):  
Comparative Analysis ◽  
Heating Temperature ◽  
Foam Glass ◽  
Microwave Energy ◽  
Glass Waste ◽  
The World ◽  
Manufacturing Procedure ◽  
Maximum Heating Temperature ◽  
Sample Characteristics ◽  
Maximum Heating

The paper presents an unconventional technique for manufacturing foam glass gravel. The numerous experimental results obtained by the authors in the last year using various manufacturing recipes common in the world industrial production by conventional techniques were selected and subjected to a qualitative and energy efficiency comparative analysis, aiming to determine the best foam glass gravel manufacturing procedure under the conditions of the use of the microwave energy. The optimum recipe was composed of 83% glass waste, 1 % glycerol, 8 % sodium silicate and 8 % water. The maximum heating temperature reached 823 ºC with a very economical energy consumption of 0.88 kWh/kg. The sample characteristics were apparent density-0.24 g/cm3, porosity-89.1% with pore size between 0.3 - 0.6 mm, thermal conductivity-0.063 W/m·K and compressive strength - 5.9 MPa, almost similar to those industrially obtained.

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