Thermodynamic analysis of triple effect ammonia–water absorption compression (hybrid) cycle

2021 ◽  
pp. 095440892199568
Author(s):  
CP Jawahar
Keyword(s):  
Water Absorption ◽  
Energy Analysis ◽  
Cooling Capacity ◽  
Coefficient Of Performance ◽  
Working Fluid ◽  
Performance Parameters ◽  
Evaporator Temperature ◽  
Ammonia Water ◽  
Absorption Cycle ◽  
Hybrid Cycle

This paper presents the energy analysis of a triple effect absorption compression (hybrid) cycle employing ammonia water as working fluid. The performance parameters such as cooling capacity and coefficient of performance of the hybrid cycle is analyzed by varying the temperature of evaporator from −10 °C to 10 °C, absorber and condenser temperatures in first stage from 25 °C to 45 °C, degassing width in both the stages from 0.02 to 0.12 and is compared with the conventional triple effect absorption cycle. The results of the analysis show that the maximum cooling capacity attained in the hybrid cycle is 472.3 kW, at 10 °C evaporator temperature and first stage degassing width of 0.12. The coefficient of performance of the hybrid cycle is about 30 to 65% more than the coefficient of performance of conventional triple effect cycle.

scholarly journals Identification of Existing Challenges and Future Trends for the Utilization of Ammonia-Water Absorption–Compression Heat Pumps at High Temperature Operation

2021 ◽  
Vol 11 (10) ◽  
pp. 4635
Author(s):  
Marcel Ulrich Ahrens ◽  
Maximilian Loth ◽  
Ignat Tolstorebrov ◽  
Armin Hafner ◽  
Stephan Kabelac ◽  
...  
Keyword(s):  
High Temperature ◽  
Water Absorption ◽  
Industrial Sector ◽  
Heat Pumps ◽  
Working Fluid ◽  
Large Temperature ◽  
Future Trends ◽  
Ammonia Water ◽  
Starting Point ◽  
High Temperature Operation

Decarbonization of the industrial sector is one of the most important keys to reducing global warming. Energy demands and associated emissions in the industrial sector are continuously increasing. The utilization of high temperature heat pumps (HTHPs) operating with natural fluids presents an environmentally friendly solution with great potential to increase energy efficiency and reduce emissions in industrial processes. Ammonia-water absorption–compression heat pumps (ACHPs) combine the technologies of an absorption and vapor compression heat pump using a zeotropic mixture of ammonia and water as working fluid. The given characteristics, such as the ability to achieve high sink temperatures with comparably large temperature lifts and high coefficient of performance (COP) make the ACHP interesting for utilization in various industrial high temperature applications. This work reviews the state of technology and identifies existing challenges based on conducted experimental investigations. In this context, 23 references with capacities ranging from 1.4 kW to 4500 kW are evaluated, achieving sink outlet temperatures from 45 °C to 115 °C and COPs from 1.4 to 11.3. Existing challenges are identified for the compressor concerning discharge temperature and lubrication, for the absorber and desorber design for operation and liquid–vapor mixing and distribution and the choice of solution pump. Recent developments and promising solutions are then highlighted and presented in a comprehensive overview. Finally, future trends for further studies are discussed. The purpose of this study is to serve as a starting point for further research by connecting theoretical approaches, possible solutions and experimental results as a resource for further developments of ammonia-water ACHP systems at high temperature operation.

scholarly journals Investigation on the improvement of car air conditioning system performance using an ejector

2018 ◽  
Vol 197 ◽  
pp. 08013
Author(s):  
Enang Suma Arifianto ◽  
Ega Taqwali Berman ◽  
Mutaufiq Mutaufiq
Keyword(s):  
System Performance ◽  
Test Procedure ◽  
Cooling Capacity ◽  
Coefficient Of Performance ◽  
Working Fluid ◽  
Refrigeration Cycle ◽  
Air Conditioner ◽  
Air Conditioning System ◽  
Compressor Work ◽  
R 134A

The purpose of this research is to know the improvement of car air conditioner system performance using an ejector. The study was conducted on a car engine with power 100 PS (74 kW) @ 5000 rpm. The test procedure is carried out under two conditions: the normal refrigeration cycle mode and the refrigeration cycle mode with the ejector. The working fluid used in the refrigeration cycle is R-134a. Performance data was measured on engine revolutions ranging from 1500 - 3000 rpm. Finally, the results showed that ejector usage on AC system generates an increase in the refrigeration effect and coefficient of performance (COP) of 25% and 22%, respectively. This has implications to better cooling capacity and compressor work that is lighter.

Optimized Refrigerant Flow Rate and Dimensions of the Ejector Employed in a Modified Ejector Vapor Compression System

2020 ◽  
Vol 28 (04) ◽  
pp. 2050038
Author(s):  
Dishant Sharma ◽  
Gulshan Sachdeva ◽  
Dinesh Kumar Saini
Keyword(s):  
Flow Rate ◽  
Cooling System ◽  
Cooling Capacity ◽  
Coefficient Of Performance ◽  
Vapor Compression ◽  
Evaporator Temperature ◽  
Proposed Model ◽  
Condenser Temperature ◽  
Vapor Compression System ◽  
Vapor Compression Cooling

This paper presents the analysis of a modified vapor compression cooling system which uses an ejector as an expansion device. Expanding refrigerant in an ejector enhances the refrigeration effect and reduces compressor work. Therefore, it yields a better coefficient of performance. Thermodynamic analysis of a constant area ejector model has been done to obtain primary dimensions of the ejector for given condenser and evaporator temperature and cooling capacity. The proposed model has been used to design the ejector for three refrigerants; R134a, R152a and R1234yf. The refrigerant flow rate and the diameters at various sections of the ejector have been obtained by doing numerical modeling in Engineering Equation Solver (EES). Refrigerant R1234yf demanded the highest diameter requirements at a fixed 5∘C evaporator temperature and 40∘C condenser temperature for a given range of cooling load. Both primary and secondary refrigerants flow rates are higher for R1234yf followed by R134a and then R152a.

Compact Diesel Engine Waste-Heat Driven Ammonia-Water Absorption Heat Pump Modeling and Performance Maximization Strategies

2021 ◽  
pp. 1-28
Author(s):  
Christopher M. Keinath ◽  
Jared Delahanty ◽  
Srinivas Garimella ◽  
Michael A. Garrabrant
Keyword(s):  
Heat Exchanger ◽  
Water Absorption ◽  
Heat Pump ◽  
Waste Heat ◽  
Cooling Capacity ◽  
Operating Conditions ◽  
Heat Transfer Fluid ◽  
Ammonia Water ◽  
Absorption Heat Pump ◽  
Wide Range

Abstract An investigation of the best ways to achieve optimal performance from a waste-heat-driven ammonia-water absorption heat pump over a wide range of operating conditions is presented. Waste-heat is recovered using an exhaust gas heat exchanger and delivered to the desorber by a heat transfer fluid loop. The absorber and condenser are hydronically coupled in parallel to an ambient heat exchanger for heat rejection. The evaporator provides chilled water for space-conditioning with a baseline cooling capacity of 2 kW. A detailed thermodynamics model is developed to simulate performance and develop strategies to achieve the best performance in both cooling and heating modes over a range of operating conditions. These parametric studies show that improved coefficients of performance can be achieved by adjusting the coupling fluid temperatures in the evaporator and the condenser/absorber as the ambient temperature varies. With the varying return temperatures, the system is able to provide the 2 kW design cooling capacity for a wide range of ambient temperatures.

Effect of Refrigerant on the Exergy Loss and Performance in Air Conditioner Using Ejector as Expansion Device

2015 ◽  
Vol 1125 ◽  
pp. 531-535 ◽  
Author(s):  
Vina Serevina ◽  
Sumeru ◽  
Henry Nasution
Keyword(s):  
Ambient Temperature ◽  
Energy Analysis ◽  
Numerical Approach ◽  
Cooling Capacity ◽  
Exergy Loss ◽  
Working Fluid ◽  
Air Conditioner ◽  
And Performance

This paper presents a numerical approach to determine the exergy loss in an air conditioner using (A/C) R22 and R290 as working fluid. The exergy loss should be minimized in order to increase the performance of the air conditioner. The present study investigates the A/C with cooling capacity of 2.4 kW. The results show that the total exergy loss of R290 is lower than that of R222, viz. 0.667 and 0.857 kW, respectively. This indicates that the use of R290 in the air conditioner using ejector as expansion device will generate a better COP improvement than that of R22. In addition, energy analysis shows that the COP improvements using R290 is higher than that of R22, for instance, 12.24 and 8.15% for R290 and R22, respectively, at the ambient temperature of 35°C.

Performance Study and Energy Saving Process Analysis of Hybrid Absorption-Compression Refrigeration Cycles

2016 ◽  
Vol 138 (6) ◽  
Author(s):  
Na Zhang ◽  
Noam Lior ◽  
Wei Han
Keyword(s):  
Low Temperature ◽  
Energy Saving ◽  
Internal Heat ◽  
Exergy Efficiency ◽  
Coefficient Of Performance ◽  
Cycle Performance ◽  
Vapor Compression ◽  
Temperature Heat ◽  
Absorption Cycle ◽  
Hybrid Cycle

In an attempt to improve the performance of hybrid absorption and mechanical vapor compression refrigeration systems and to determine the fundamental reasons for such improvements, two configurations of the hybrid refrigeration cycle with a booster compressor at different positions of the cycle (between the evaporation and the absorber, or between the generator and the condenser) are simulated and analyzed. The interrelation between the two subcycles and the hybridization principle have been explored and clarified. An NH3/H2O-based hybrid cycle is the basis of this simulation. It was found that (1) the hybrid cycle performance is mainly governed by the interaction between its two subcycles of mechanical compression and thermal compression and their respective energy efficiencies, and (2) the hybrid cycle primary energy-based coefficient of performance (COP) was higher by up to 15% (without internal heat recuperation) as compared with the nonhybrid absorption cycle, (3) in comparison with the nonhybrid absorption and vapor compression cycles working in the same temperature regions, the more efficient use of low-temperature heat by cascade utilization of the two energy inputs (heat rate and mechanical power) with different energy quality, and the enhanced refrigeration ability of low-temperature heat are the basic reasons for the hybrid cycle performance improvement and significant energy saving, (4) the hybrid cycle achieves an exergy efficiency of 36.5%, which is 27% higher than that of the absorption cycle, and 4.5% higher than the vapor compression cycle, achieving a thermal-driving exergy efficiency of 37.5% and mechanical work saving ratio up to 64%.

Numerical Study of Ejector as an Expansion Device in Split-Type Air Conditioner

2013 ◽  
Vol 388 ◽  
pp. 101-105 ◽  
Author(s):  
Kasni Sumeru ◽  
Nasution Henry ◽  
Farid Nasir Ani
Keyword(s):  
Capillary Tube ◽  
Numerical Study ◽  
Geographical Area ◽  
Numerical Approach ◽  
Cooling Capacity ◽  
Coefficient Of Performance ◽  
Working Fluid ◽  
Air Conditioner ◽  
Constant Area ◽  
Condenser Temperature

This paper presents a numerical approach for determining the motive nozzle and constant-area of an ejector as an expansion device, based on cooling capacity of the split-type air conditioner using R22 as working fluid. The use of an ejector as an expansion device in split-type air conditioner can enhance the coefficient of performance (COP) system. Typically, the split-type air conditioner may be installed on the geographical area with moderate or high outdoor air temperature using capillary tube. For this reason, the motive nozzle and constant-area diameters of the ejector must be designed according to these conditions. The diameters of the ejector are crucial in improving the COP. The results showed that the motive nozzle diameter is constant (1.14 mm) with variations of the condenser temperature, whereas the constant-area diameter decreases as the condenser temperature increases.

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