An Exploratory Study of an Oxyfuel Combustion Turbine Cycle With Vapor Absorption Refrigeration and Water Production

2009 ◽  
Author(s):  
Walter Shelton ◽  
Patrick Le ◽  
William E. Lear ◽  
Richard Dennis ◽  
John Wimer
Keyword(s):  
Co2 Capture ◽  
Exploratory Study ◽  
Combined Cycle ◽  
Coefficient Of Performance ◽  
Water Production ◽  
Absorption Refrigeration ◽  
Separation Unit ◽  
Oxyfuel Combustion ◽  
Vapor Absorption ◽  
Vapor Absorption Refrigeration

The preliminary findings of an exploratory study conducted on a novel Oxyfuel Combustion Turbine Cycle (OCTC) using ASPEN PLUS for a range of 40% to 90% CO2 capture are presented. Starting from a GE Energy IGCC, the OCTC retains the Gasifier with a Radiant Cooler-only section and the Warm-Gas-Clean Up (WGCU) section with the desulfurization process eliminated for a combined carbon and sulfur co-sequestration approach. The conventional gas turbine combined cycle is also removed. With no integration between the Air Separation Unit (ASU) and the modified oxyfuel combustion turbine, the High Pressure (HP) ASU is replaced by a Low pressure (LP) ASU. The added attributes of this novel coal-based power system configuration are (1) the Vapor Absorption Refrigeration System (VARS), (2) the associated water production in the VARS evaporator, (3) the recirculation of combustor flue gas for lower NOx emissions and additional power production, as well as (4) an original concept of carbon dioxide compression as proposed by SouthWest Research Institute (SwRI) and Dresser Rand (D-R). Assuming a reasonable Coefficient of Performance (COP) for the VARS, the overall process efficiency results (about 35% HHV) were equivalent or even better when compared with studies of current simulated IGCC systems with CO2 capture. Once an optimum scheme has been finalized in future activities, an economic analysis would be conducted. The combined performance and economic results could then be compared with alternate advanced coal based power systems.

Modified Operating Parameter-Based Iyer Correlation for the Coefficient of Performance (COP) Prediction of Different Fluid Pairs in Double-Effect Vapor Absorption Refrigeration (VAR) Cycles

2021 ◽  
Author(s):  
Muhammad Saad Khan ◽  
Sambhaji T. Kadam ◽  
Alexios-Spyridon Kyriakides ◽  
Ibrahim Hassan ◽  
Athanasios I. Papadopoulos ◽  
...  
Keyword(s):  
Renewable Energy ◽  
Renewable Energy Sources ◽  
Double Effect ◽  
Energy Utilization ◽  
Coefficient Of Performance ◽  
Absorption Refrigeration ◽  
Dual Effect ◽  
Data Set ◽  
Vapor Absorption ◽  
Vapor Absorption Refrigeration

Abstract Vapor absorption refrigeration (VAR) is a sustainable alternative to the conventional vapor compression refrigeration (VCR) cycle, owing to its lower non-renewable energy requirements and potentially for exploitation of renewable energy sources. Traditionally, the coefficient of performance (COP) of the conventional single effect VAR cycle is considerably lower than VCR cycles. This provides room for improvement which can be attained through double effect VAR cycles that provide relatively higher performance. The COP of the dual effect VAR cycle is enhanced due to the waste/rejected heat energy utilization from the condenser or the absorber into a secondary generator. Models that correlate the COP of the double effect VAR cycle with operating parameters are not available in the open literature, with Iyer’s correlation being the only exception. This work applies this COP correlation using literature data for double effect VAR that operate with a variety of refrigerant and absorbent pairs. A comprehensive Mean Absolute Percentage Error (MAPE) analysis is performed for more than 2028 data points of various fluid pairs. Results reveal that MAPE (86.6–839%) values appear to be quite high for the reported correlation. Furthermore, the model is optimized using the proposed data set, considerably reducing the MAPE up to 36.03%. The results also indicate that due to the lack of fluid-specific parameters, the application of this correlation may not support the development of new double effect VAR cycles. Therefore, it is crucial to establish a performance-based correlation that considers both operational parameters and fluid parameters to assess the performance of new and efficient dual effect VAR cycles.

Testing and Modeling of a Semi-Closed Gas Turbine Cycle Integrated With a Vapor Absorption Refrigeration System

2006 ◽  
Author(s):  
J. R. Khan ◽  
W. E. Lear ◽  
S. A. Sherif ◽  
E. B. Howell ◽  
J. F. Crittenden ◽  
...  
Keyword(s):  
High Pressure ◽  
Combined Cycle ◽  
Absorption Refrigeration ◽  
Ambient Conditions ◽  
Power Cycle ◽  
High Pressure Compressor ◽  
Refrigeration Unit ◽  
Vapor Absorption ◽  
Absorption Refrigeration System ◽  
Vapor Absorption Refrigeration

A novel cooling and power cycle has been proposed that combines a semi-closed cycle gas turbine called the High Pressure Regenerative Turbine Engine (HPRTE) with a vapor absorption refrigeration system (VARS). The refrigeration cycle (VARS) interacts with the power cycle (HPRTE) solely through heat transfer in the generator and the evaporator. 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. Water produced as a product of combustion is intentionally condensed in the evaporator of the VARS, which is designed to provide sufficient cooling for three purposes: chilling the inlet air to the high pressure compressor, water extraction, and for an external cooling load. In a previous study, the combined cycle was modeled using zero-dimensional steady-state thermodynamics, with the specified values of efficiencies and pressure drops for the turbo-machinery and heat exchangers. The model predicts that the combined cycle with steam blade cooling for a medium-sized engine will have a thermal efficiency of 49%, in addition to the external refrigeration load generated in the cycle which is 13% of the net work output. It also produces about 1.4 kg of water for each kg of fuel (propane) consumed. A small experimental unit demonstrating the HPRTE/VARS combined cycle has been constructed and is currently being tested in the Energy & Gas-dynamic Systems Laboratory at the University of Florida. A 45 HP Rover 1S-60 engine is integrated with a NH3/H2O vapor absorption refrigeration unit having a capacity of 19 Ton Refrigeration. The engine flow-path has been significantly modified to include partial recirculation of exhaust products, turbocharging, and recuperation, thus implementing the HPRTE concept. In addition, a significant modeling effort has been undertaken to simulate the combined cycle operation under design and off-design conditions. Initial experimental results show good agreement with the model predictions, including overall efficiency and water extraction rates.

Thermodynamic Modeling and Performance Optimization of a Solar-Assisted Vapor Absorption Refrigeration System (SAVARS)

2020 ◽  
Vol 28 (01) ◽  
pp. 2050006
Author(s):  
Boris Huirem ◽  
Pradeepta Kumar Sahoo
Keyword(s):  
Performance Optimization ◽  
Fruits And Vegetables ◽  
Coefficient Of Performance ◽  
Working Fluid ◽  
Absorption Refrigeration ◽  
Performance Parameters ◽  
Refrigeration System ◽  
Vapor Absorption ◽  
Absorption Refrigeration System ◽  
Vapor Absorption Refrigeration

A thermodynamic steady-state model for a single-effect lithium bromide–water (LiBr-H2O)-based vapor absorption refrigeration system of 17.5[Formula: see text]kW capacities has been presented using the first and second laws of thermodynamics. The mass, energy and exergy balance equations in each component of the vapor absorption cycle have been fitted into a computer program to carry out the calculation using the thermo-physical properties of the working fluid. The performance parameters such as coefficient of performance (COP), exergy coefficient of performance (ECOP), total exergy destruction (TED), etc. have been evaluated considering different temperatures in generator and evaporator, different LiBr concentrations in the weak and strong LiBr-H2O solution and different solution heat exchanger effectiveness. The model evaluated the optimum performance parameters like COP, ECOP, TED, etc. of the vapor absorption system by using Design Expert-12 software for an application like on-farm cooling or transit storage of fruits and vegetables.

EXERGY ANALYSIS OF A LiBr–H2O VAPOR ABSORPTION REFRIGERATION PLANT: A CASE STUDY

2014 ◽  
Vol 22 (02) ◽  
pp. 1450010 ◽  
Author(s):  
SANJEEV ANAND ◽  
ANKUSH GUPTA ◽  
SUDHIR KUMAR TYAGI
Keyword(s):  
Performance Optimization ◽  
Exergy Analysis ◽  
Heat Rate ◽  
Exergy Efficiency ◽  
Exergy Loss ◽  
Absorption Refrigeration ◽  
Actual System ◽  
Evaporator Temperature ◽  
Vapor Absorption ◽  
Vapor Absorption Refrigeration

This communication presents the energy and exergy analysis of an actual double effect steam powered LiBr – H 2 O vapor absorption refrigeration plant. Exergy loss, COP, exergy efficiency and heat rate for each component of the system are calculated. The effect of generator as well as evaporator temperature on the COP and exergy efficiency is evaluated and it is found that the irreversibility rate is highest in the generator while it is found to be the lowest in the case of absorber and condenser. It is also found that the COP of the system increases with the increase in the evaporator temperature while it is found to be reverse in case of exergy efficiency. Results revealed that average exergy loss is highest in the generator as compared to other components. The results obtained are helpful for designers to bring changes in the actual system for performance optimization and less wastage of energy. The study clearly explain the operational and maintenance problems in the machine and point out the areas of energy wastage which the operational engineer should look into for the optimum operation of the plant.

Space Cooling Using the Concept of Nanofluids-Based Direct Absorption Solar Collectors

2012 ◽  
Author(s):  
Vivek Vishwakarma ◽  
Nitin Singhal ◽  
Vikrant Khullar ◽  
Himanshu Tyagi ◽  
Robert A. Taylor ◽  
...  
Keyword(s):  
Solar Collector ◽  
Air Conditioning ◽  
Thermal Storage ◽  
Temperate Climate ◽  
Absorption Refrigeration ◽  
Direct Absorption ◽  
Parabolic Trough ◽  
Space Cooling ◽  
Vapor Absorption ◽  
Vapor Absorption Refrigeration

A solar-energy based vapor absorption refrigeration system is potentially an excellent alternative air-conditioning system. However, there are several research challenges to ensure sufficient efficiency and reliability for ensuring widespread implementation. Integration of a parabolic trough solar collector utilizing a mixture of nanoparticles and water with a vapor absorption system has the potential to significantly enhance the efficiency of the system. Such a system makes use of the superior thermo-physical properties of the nanofluid compared to the base fluid. Moreover, the direct absorption phenomenon of solar radiation through interaction with the participating medium (nanofluid) results in a higher temperature rise of the medium in conjunction with higher operating efficiencies as well. At the same time there are certain challenges that need to be identified and addressed in the implementation of this novel concept. For instance, to make it reliable, the system further needs to be integrated with a thermal storage system which facilitates air-conditioning even during non-sunshine hours. Integration of vapor absorption refrigeration technology, parabolic trough with water-nanoparticles mixture as the absorbing medium and a thermal storage facility is the uniqueness of this design which under certain conditions and locations may prove to be an efficient and reliable substitute to the conventional electrical air-conditioning systems. In this particular study a space cooling application for approximately 100 Tons of refrigeration is studied. Hourly variation in sunlight as well as seasonal changes for temperate climate conditions is considered. Parameters such as the cooling load of the space, and waste heat produced by electronics are evaluated. The cooling system driven by the nanofluid-based concentrated parabolic solar collector is mathematical modeled and then the optimization is done by varying the nanoparticle size and volume fraction in order to obtain the best result for collector outlet temperature, thermal efficiency and optical efficiency.

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