scholarly journals OPERATING PARAMETERS OF ABSORPTION REFRIGERATION UNIT INFLUENCE ON THE ZONE OF DEGASSING

Author(s):  
Elena V. Bogatyreva ◽  
2017 ◽  
Vol 39 (4) ◽  
pp. 439 ◽  
Author(s):  
Josegil Jorge de Araújo ◽  
Carlos Antonio Cabral dos Santos ◽  
Carlos Almir de Holanda ◽  
João Batista Furlan Duarte ◽  
Alvaro Antonio Villa Ochoa ◽  
...  

2020 ◽  
Vol 8 (2) ◽  
pp. 3-9
Author(s):  
E.A. Belyanovskaya ◽  
◽  
G.M. Pustovoy ◽  
A.I. Sklyarenko ◽  
M.P. Sukhyy ◽  
...  

The work is focused on the development of an effective algorithm for calculating the operational characteristics of a steamcompressive chilling machine with an adsorptive chilling unit, which involves a cold box, an adsorber, an evaporator and a condenser, water being used as a refrigerant. An algorithm for calculating the operating parameters of the adsorptive chilling unit has been developed, which includes the determination of the cooling capacity of the steam compressor refrigeration unit, the heat load on the condenser, the power consumed by the compressor, the coefficient of performance of the steam compressor refrigeration unit, as well as the calculation of the mass of water, the mass of the adsorbent, the refrigerating capacity, the coefficient of performance of the adsorptive chilling unit and the coefficient of useful energy utilization of a steam compressive chilling machine with an adsorption chilling unit. The chilling capacity and the coefficient of performance of the adsorption chilling unit are estimated under the operating conditions of a typical steam compression chilling machine. The crucial factors affecting the efficiency of the adsorptive chilling unit are analyzed. It has been established that the chilling capacity, the coefficient of performance of the adsorption refrigeration module and the energy efficiency of the installation are determined by the thermal load on the condenser, and, therefore, by the mass of water that is desorbed and evaporated. The coefficient of performance of the adsorption chilling unit and the efficiency of the steam compressor chilling machine with the adsorptive chilling unit are estimated to be 0.878 and 4.64. The criteria for the selection of adsorbents for the adsorption module are analyzed. The temperature of regeneration is determined by the temperatures in the condenser, and the limit adsorption affects the mass of the adsorbent and the size of the adsorber. A comparison of the efficiency of adsorptive chi l l ing uni t based on silicoaluminophosphates and composite adsorbents «silica gel – sodium acetate» is carried out. The prospects of using composites «silica gel – СН3СООNa» are shown. The optimal composition of the composite was established, which corresponds to the minimal size of the adsorber, (80% sodium acetate and 20% silica gel). The prospects of using adsorptive conversion of thermal energy for utilization of low-potential thermal energy during the operation of steam compressive chilling machine are shown. Keywords: adsorptive conversion of heat energy, composite adsorbent, steam compressive chilling unit, adsorption, adsorptive capacity.


1985 ◽  
Vol 107 (3) ◽  
pp. 189-195 ◽  
Author(s):  
S. C. Chang ◽  
J. A. Roux

A solar zeolite-water absorption refrigeration unit was studied. Thermodynamic expressions were derived to predict the system performance. The operating range and optimum design parameters for the zeolite system were determined. The main parameters governing performance were: solar collector type, ambient temperature, and absorber properties. Results are shown for various solar collector types and various zeolite types. A desorption initiation temperature is shown to exist. The analysis is not based on empirical heat of absorption data, but rather on a zeolite properties relationship (log Pv versus 1/Tz) to determine system performance.


2015 ◽  
Vol 138 (2) ◽  
Author(s):  
T. K. Gogoi

In this paper, an inverse problem is solved for estimating parameters of a steam-driven water–lithium bromide (LiBr) vapor absorption refrigeration system (VARS) using a differential evolution (DE)-based inverse approach. Initially, a forward model simulates the steady-state performance of the VARS at various operating temperatures and evaporator cooling loads (CLs). A DE-based inverse analysis is then performed to estimate the operating parameters taking VARS coefficient of performance (COP), CL, total irreversibility, and exergy efficiency as objective functions (one objective function at a time). DE-based inverse technique estimates the parameters within a very short period of elapsed time. Over 50 and 100 numbers of generations are sufficient for retrieval of COP and exergy efficiency, respectively, while it requires 150 generations for total irreversibility and CL. The study reveals that multiple combinations of parameters within a given range satisfy a particular objective function which serves as design guidelines in selecting appropriate operating parameters.


2017 ◽  
Vol 3 ◽  
pp. 31-40
Author(s):  
Andrey Kholodkov ◽  
Aleksandr Titlov

Currently, developers of modern refrigeration equipment, in accordance with the plans of the UN, are moving to natural refrigerants (hydrocarbons, carbon dioxide and ammonia) that do not have an adverse technological impact on the ecosystem of the planet. In domestic refrigeration technology, one of the options is absorption refrigeration units, the working body of which is an aqueous ammonia mixture with the hydrogen addition. Having a number of unique advantages over compression analogs, absorption systems are characterized by lower energy characteristics. As the analysis shows, the maximum thermodynamic losses in the absorption aggregates are concentrated in the generating unit when the ammonia is evaporated, it is purified from water vapor and transported to the evaporator. In this connection, the mathematical modeling of the thermal regimes of the reflux condenser is performed, which is responsible for purification and transportation of ammonia vapor. Modeling is carried out on standard designs of absorption refrigeration units taking into account reasonable assumptions and results of own experimental researches. A cellular model is used. Stationary operating modes are modeled due to the high thermal inertia of the processes in the reflux condenser. As a result, the perspective of the thermal insulation installation throughout the reflux section is shown, which makes it possible to increase the energy efficiency by 17 ... 22 %


Author(s):  
J. R. Khan ◽  
W. E. Lear ◽  
S. A. Sherif

A thermodynamic performance analysis is performed on a novel cooling and power cycle that combines a semi-closed cycle gas turbine called the High Pressure Regenerative Turbine Engine (HPRTE) with an absorption refrigeration unit. Waste heat from the recirculated combustion gas of the HPRTE is used to power the absorption refrigeration unit, which cools the high-pressure compressor inlet of the HPRTE to below ambient conditions and also produces excess refrigeration, in an amount which depends on ambient conditions. The cycle is modeled using traditional one-dimensional steady-state thermodynamics, with state-of-the-art polytropic efficiencies and pressure drops for the turbo-machinery and heat exchangers, and accurate y correlations for the properties of the LiBr-water mixture and the combustion products. Water produced as a product of combustion is intentionally condensed in the evaporator of the vapor absorption refrigeration system. The mixture properties of air account for the water removal rate. The vapor absorption refrigeration unit is designed to provide sufficient cooling for water extraction. The cycle is shown to operate with a thermal efficiency approaching 58% for a turbine inlet temperature of 1400 °C in addition to producing about 0.45 liters of water per liter of fuel consumed. Also at the above operating condition the ratio of the refrigeration effect to the net work output from the system is equal to 0.8. The ratio of mass of water extracted to the mass of fresh air inlet into the combined cycle is obtained for different values of cycle parameters, namely turbine inlet temperature, recuperator inlet temperature and the low pressure compressor ratio. The maximum value of this ratio is found to be around 0.11. It is found that it is a strong function of the recirculation ratio and it decreased by 22% as the recirculation ratio is decreased by 70%. The thermodynamic impacts of water extraction on the system performance are also discussed. Based on these results, and prior results, which showed that the HPRTE is very compact, it appears that this cycle would be ideally suited for distributed power and vehicle applications, especially ones with associated air conditioning loads.


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