scholarly journals Thermodynamic Analysis of a Combined Single Effect Vapour Absorption System and tc-CO2 Compression Refrigeration System

2021 ◽  
Vol 2 (2) ◽  
pp. 87-98
Author(s):  
Abhishek Verma ◽  
S. C. Kaushik ◽  
S. K. Tyagi
Keyword(s):  
Low Temperature ◽  
Waste Heat ◽  
Electricity Consumption ◽  
Combined Cycle ◽  
Refrigeration System ◽  
Absorption System ◽  
Combined System ◽  
Single Effect ◽  
Exergetic Analysis ◽  
Low Temperature Refrigeration

Transcritical CO2 refrigeration system is coupled with the single effect vapour absorption with LiBr-water as a working pair having an objective to enhance the performance of low temperature transcritical refrigeration system while using natural working pair and to reduce the electricity consumption to produce low temperature refrigeration. The high grade waste heat rejected in the gas cooler of tc-CO2 compression refrigeration system (TCRS) is utilized to run the single effect vapour absorption system (SEVAR) to enhance the energy efficiency of the system. The gas cooler in the transcritical CO2 system is having heat energy at high temperature and pressure, which is utilized to run the vapour absorption system, while the other refrigerant heat exchanger provides subcooling to further enhance the performance. The combined cycle can provide refrigeration temperature at different levels, to use it for different applications. Energetic and exergetic analysis have been done to analyze the combined system to compute the performance parameters and the irreversibilities occurring in different components to further increase the performance. The combined system is optimized for various heat rejection and refrigeration temperatures. The COP of the combined system has been enhanced by to 24.88% while the enhancement in exergetic efficiency (ηex) is observed as 10.14% respectively over tradition transcritical CO2 compression refrigeration system, with -10°C as an evaporation (TCRS cooling) temperature and exit temperature of gas cooler T4 being 40°C. Doi: 10.28991/HIJ-2021-02-02-02 Full Text: PDF

Analysis of a Combined Power and Ejector Refrigeration Cycle for Low Temperature Heat Sources

2009 ◽  
Author(s):  
Bin Zheng ◽  
Yiwu Weng
Keyword(s):  
Low Temperature ◽  
Waste Heat ◽  
Organic Rankine Cycle ◽  
Rankine Cycle ◽  
Combined Cycle ◽  
Refrigeration Cycle ◽  
Heat Sources ◽  
Working Fluids ◽  
Temperature Heat ◽  
Cycle Efficiency

This paper presents a combined power and ejector refrigeration cycle for low temperature heat sources. The proposed cycle combines the organic Rankine cycle and the ejector refrigeration cycle. It can be used as an independent cycle powered by the low temperature sources, such as solar energy, geothermal energy, or as a bottom cycle of the conventional power plant for the recovery of low temperature waste heat. A program was developed to calculate the performance of the combined cycle. Several substances were selected as the working fluids including R113, R123, R245fa, R141b and R600. Simulation results show that R141b has the highest cycle efficiency, followed by R123, R113, R600 and then R245fa. While the working fluids are calculated by per unit, R600 can produce more power and refrigeration outputs due to the large latent heat. Simulations at different generating temperatures, evaporating temperatures and condensing temperatures were also discussed.

scholarly journals Recovery and Transport of Industrial Waste Heat for Their Use in Urban District Heating and Cooling Networks Using Absorption Systems

2019 ◽  
Vol 10 (1) ◽  
pp. 291 ◽  
Author(s):  
Antonio Atienza-Márquez ◽  
Joan Carles Bruno ◽  
Alberto Coronas
Keyword(s):  
Low Temperature ◽  
Waste Heat ◽  
District Heating ◽  
Distribution Networks ◽  
Energy Performance ◽  
Hot Water ◽  
Absorption System ◽  
Urban District ◽  
Heating And Cooling ◽  
Water Mass Flow Rate

The use of industrial excess heat in district heating networks is very attractive. The main issue is the transport of the heat from the point of generation to the local distribution network, in a way similar to the structure of electricity transport and distribution networks. Absorption systems have been proposed to transport and distribute waste heat using two absorption stations. In one of them (step-up station), industrial heat at a low temperature is pumped to a higher temperature to facilitate its transport and at the same time increase the temperature difference between the supply and return streams, in this way reducing the hot water mass flow rate circulating through the heat transport network. Heat is then used in a second absorption system (step-down station) to provide heat to a low temperature local district network. In this paper, several absorption system configurations are analyzed for both stations. A detailed thermodynamic analysis of each configuration is performed using selected energy performance indicators to calculate its global performance. The implementation of these kind of systems could enable the use of waste heat to produce heating and cooling for smart communities located a few dozens of kilometers away from industrial sites.

Effect of Inlet Air Refrigeration on the Performance of Combined Cycle Power Plants

2004 ◽  
Author(s):  
G. Srivastava ◽  
R. Yadav
Keyword(s):  
Heat Source ◽  
Power Plants ◽  
Combined Cycle ◽  
Air Cooling ◽  
Specific Work ◽  
Vapor Compression ◽  
Refrigeration System ◽  
Absorption System ◽  
Vapor Absorption ◽  
Gas Turbine Exhaust

In the present work an attempt has been made to study the effect of inlet air refrigeration on the performance of combined cycle power plants. The inlet air cooling for the chosen combined cycle configuration may be done by means of employing a refrigeration system such as vapor compression and vapor absorption system, which derive the energy input from the system itself. In the vapor absorption system, the input energy to generator is given by three possible heat source from the system namely from the gas turbine exhaust, steam bled from steam turbine and exhaust gas from the exit of heat recovery steam generator (HRSG). It has been observed that the vapor absorption system with HRSG exhaust as heat source to the generator is the better option followed by the vapor compression refrigeration system for compressor inlet air cooling. The cooled compressed inlet air up to 280K from 300K improves the plant specific work around 4% and plant efficiency around 0.39 percentage point for the combined cycle using vapor compression system.

Parametric Study of a Combined Power and Cooling Thermodynamic Cycle for Low Temperature Heat Sources

2009 ◽  
Author(s):  
Ricardo Vasquez Padilla ◽  
Gokmen Demirkaya ◽  
D. Yogi Goswami ◽  
Elias L. Stefanakos
Keyword(s):  
Low Temperature ◽  
Parametric Study ◽  
Waste Heat ◽  
Ammonia Concentration ◽  
Combined Cycle ◽  
Operating Conditions ◽  
Optimum Operating ◽  
Working Fluid ◽  
Basic Solution ◽  
Water Mixture

A combined power/cooling cycle, which combines the Rankine and absorption refrigeration cycles, uses ammonia-water mixture as a working fluid and produces power and refrigeration while power is the primary goal. This cycle, also known as the Goswami Cycle, can be used as a bottoming cycle using waste heat from a conventional power cycle or as an independent cycle using low temperature sources such as geothermal and solar energy. This paper presents a parametric analysis of the combined cycle. Parametric study of the cycle was carried out in the commercial software Chemcad 6.1. The thermodynamic property data used in simulations were validated with experimental data. Chemcad model was also compared with simulations previously carried out in the process simulator Aspen Plus. The agreement between the two sets has proved the accuracy of the model developed in Chemcad. Then, optimum operating conditions were found for a range of ammonia concentration in the basic solution, isentropic expander efficiency and boiler pressure. It is shown that the cycle can be optimized for net work, cooling output, effective first and exergy efficiencies.

A combined system utilizing LNG and low-temperature waste heat energy

2016 ◽  
Vol 101 ◽  
pp. 525-536 ◽  
Author(s):  
Mo-Geng Zhang ◽  
Liang-Ju Zhao ◽  
Chao Liu ◽  
Yi-Lin Cai ◽  
Xi-Min Xie
Keyword(s):  
Low Temperature ◽  
Waste Heat ◽  
Heat Energy ◽  
Combined System

scholarly journals Research and Development of Ship Waste Heat Driven S-CO2 Power Generation Coupled T-CO2 Refrigeration System

2020 ◽  
Vol 194 ◽  
pp. 01036
Author(s):  
Min Li ◽  
Yongqian Zhang ◽  
Youjian Wu ◽  
Ruitao Chen ◽  
Qianxi Zhang ◽  
...  
Keyword(s):  
Power Generation ◽  
Energy Saving ◽  
Waste Heat ◽  
Total Power ◽  
Thermal Calculation ◽  
Refrigeration System ◽  
Combined System ◽  
Exhaust Temperature ◽  
Fishing Boat ◽  
Total Power Consumption

Most of the exhaust temperature of ships is above 300℃, usually this part of waste heat would be directly discharged into the environment, not fully utilized. In order to improve the energy efficiency ratio of ship storage and transportation more effectively, domestic and foreign counterparts have done a lot of technical research on the recovery and utilization of ship waste heat, but most of them are based on a single application perspective. Emphasizing the application of multi-angle combined waste heat, driven by waste heat for CO2 supercritical power generation coupling trans-critical refrigeration system was proposed and designed. While the combined system recovered waste heat for power generation, the functions of refrigerating cooling and seawater desalination were realized by using the properties of CO2 working medium. Taking Fuyuan Yu 7861 ocean-going fishing boat as a design case, the relevant thermal calculation and equipment matching of CO2 supercritical power-transcritical refrigeration system driven by waste heat recovery were targeted. The results showed that the total power consumption of the system is 34.171KW, the waste heat power generation efficiency is 12.9%, the refrigeration performance coefficient is 2.368, the energy saving effect is remarkable, and the energy saving and emission reduction are realized.

Criteria for Economic Optimization of an Absorption System Using Sources of Low Temperature

1996 ◽  
Vol 118 (2) ◽  
pp. 164-166
Author(s):  
F. Hernandez ◽  
M. Izquierdo
Keyword(s):  
Low Temperature ◽  
Heat Source ◽  
Heat Pump ◽  
Thermodynamic Function ◽  
Economic Optimization ◽  
Absorption System ◽  
Combined System

An absorption system, reduced to the equivalent combined system of three-heat-source heat pump, is optimized with economical criteria. The multiparameter thermodynamic function η combines the COP and rate of pumping, and determines that optimum. Values of μ = 0, μ = 1, and μ > 1 define three different cases of application for different markets.

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