scholarly journals Assessment of Aqueous Lithium-based Salt Solutions as Working Fluid for Absorption Chillers using Aspen Plus

2018 ◽  
Vol 17 (2) ◽  
pp. 51
Author(s):  
Adonis P. Adornado ◽  
Allan N. Soriano ◽  
Vergel C. Bungay
Keyword(s):  
Waste Heat ◽  
Cost Savings ◽  
Primary Energy ◽  
Working Fluid ◽  
Salt Solutions ◽  
Absorption Chiller ◽  
Absorption Chillers ◽  
Aqueous Salt Solutions ◽  
Direct Proportionality ◽  
Proportionality Relationship

Absorption chillers are a viable option for providing waste heat-powered coolingor refrigeration, thereby improving overall energy efficiency-less primary energy input,lower emissions, and cost savings. This study focuses on the assessment of aqueouslithium-based salt solutions as working fluid for absorption chiller in exploring thepossibility of developing new mixtures for absorption chillers to improve the performanceof the absorption refrigeration systems (ARSs). In this paper, the coefficient ofperformance (COP) of a single-effect absorption chiller using aqueous lithium-based saltsolutions (LiF-H2O, LiCl-H2O, LiBr-H2O, and LiI-H2O) as working fluid was assessed usingAspen Plus®. The simulation results obtained showed that the mass and energy were wellbalanced for all systems. Furthermore, a direct proportionality relationship between COPof absorption chillers and the van't Hoff factor, i of dissociated aqueous salt solutions wasobserved. The highest COP value is 0.8930 for LiI-H2O among others.

Experimental Investigation of the Effect of Generator Temperature on the Performance of Solution Transportation Absorption Chiller

2017 ◽  
Vol 25 (03) ◽  
pp. 1750028 ◽  
Author(s):  
Koji Enoki ◽  
Fumi Watanabe ◽  
Atsushi Akisawa ◽  
Toshitaka Takei
Keyword(s):  
Experimental Investigation ◽  
Heat Source ◽  
Waste Heat ◽  
Demand Side ◽  
Conventional System ◽  
Absorption Chiller ◽  
Ammonia Water ◽  
Absorption Chillers ◽  
Heat Demand ◽  
Normal Absorption

It is effective to recover waste heat to reduce primary energy consumption. From this point of view, we proposed and examined a new idea of heat transportation using ammonia–water as the working fluid in the system named the Solution Transportation Absorption chiller (STA). As waste heat sources are not necessarily located close to areas of heat demand, conventionally, absorption chillers are located on heat source side and produce chilled water that is transported to heat demand side through pipelines with an insulation. In contrast, the proposed system STA divides an absorption chiller into two parts. The generator and the condenser are located on heat source side while the evaporator and the absorber are on heat demand side. Both the conventional system and STA system satisfy the same boundary condition of heat recovery and heat supply to the demand side, STA can work for transferring thermal energy as the conventional system does even though the temperature of the media is ambient without an insulation. Our previous studies of the STA were based on the experimental investigation with the STA facility where the cooling power was 90[Formula: see text]kW (25.6 refrigeration ton) at the generator temperature 120[Formula: see text]C from 0[Formula: see text]m (normal absorption chiller) to 1000[Formula: see text]m. Thus, the Coefficient of Performance (COP) of STA was found to have almost the same value of 0.65 with conventional absorption chillers without depending on the transportation distances. The objective of this study is to examine the effect of generator temperature from 100[Formula: see text]C to 120[Formula: see text]C on the performance of solution transportation of ammonia–water solution, because the generator temperature is directly linked to the waste heat temperature, so its effect needs to be investigated. The experimental facility tested the performance with 0[Formula: see text]m (normal absorption chiller), 200[Formula: see text]m and 500[Formula: see text]m distance. The results indicate that the effect of the generator temperature and solution transportation distances showed no significant on the COP.

scholarly journals Combined Closed Cycle (C3) Systems for Underwater Power Generation

1992 ◽  
Author(s):  
Aristide Massardd ◽  
Gian Marid Arnulfi
Keyword(s):  
Power Generation ◽  
Power Plants ◽  
Waste Heat ◽  
Organic Rankine Cycle ◽  
Rankine Cycle ◽  
Primary Energy ◽  
Combined Cycle ◽  
Working Fluid ◽  
Mass Reduction ◽  
Efficiency Increase

In this paper three Closed Combined Cycle (C3) systems for underwater power generation are analyzed. In the first, the waste heat rejected by a Closed Brayton Cycle (CBC) is utilized to heat the working fluid of a bottoming Rankine Cycle; in the second, the heat of a primary energy loop fluid is used to heat both CBC and Rankine cycle working fluids; the third solution involves a Metal Rankine Cycle (MRC) combined with an Organic Rankine Cycle (ORC). The significant benefits of the Closed Combined Cycle concepts, compared to the simple CBC system, such as efficiency increase and specific mass reduction, are presented and discussed. A comparison between the three C3 power plants is presented taking into account the technological maturity of all the plant components.

Solution Proposal for Utilization of the Waste Heat in Refrigeration Systems

TEM Journal ◽  
2021 ◽  
pp. 177-182
Author(s):  
Halima Hadžiahmetović ◽  
Rejhana Blažević ◽  
Emina Peco
Keyword(s):  
Heat Recovery ◽  
Waste Heat Recovery ◽  
Food Industry ◽  
Energy Savings ◽  
Waste Heat ◽  
Cost Savings ◽  
Primary Energy ◽  
Industrial Processes ◽  
Industrial Companies ◽  
Simplified Solution

The possibility for utilization of waste heat from processes in the food industry is presented in this paper. The need for reuse of waste heat comes from the fact that energy consumption in industrial companies is uneconomical and that environmental pollution has increased. Therefore, one of the method of reuse of waste heat that is applicable in industrial processes is presented in the paper. Potential primary energy savings is presented by implementing the waste heat recovery in the food factory. The paper presents a simplified solution proposal for installation of heat exchangers with the aim of utilizing the waste heat of the refrigerant. The results showed that by the implementation of simple heat recovery significant annual fuel energy savings can be achieved as well as fuel cost savings.

3D CFD Analysis of a Twin Screw Expander With Different Real Gas Models for R245fa

2015 ◽  
Author(s):  
Iva Papes ◽  
Lazhar Abdelli ◽  
Joris Degroote ◽  
Jan Vierendeels
Keyword(s):  
Waste Heat ◽  
Organic Rankine Cycle ◽  
Rankine Cycle ◽  
Primary Energy ◽  
Ideal Gas ◽  
Production Costs ◽  
Working Fluid ◽  
Real Gas ◽  
Twin Screw ◽  
The Ideal

With the increasing importance of minimizing primary energy usage and complying with emission restrictions, a significant interest has been developed towards waste heat recovery from industrial processes. A large portion of this energy is available at low temperatures (350K–400K) but it can be relatively efficiently converted into mechanical power using an Organic Rankine Cycle (ORC). Twin screw expanders can be used as an alternative to turbines with their cheap production costs and well proven efficiencies. In this paper, 3D CFD simulations of a twin screw expander using R245fa as the working fluid are performed. Since the fluid properties show big deviations when using the ideal gas equation of state (EoS), the flow problem has been evaluated using different real gas models. Thermodynamic parameters for the ideal gas EoS, the cubic Aungier Redlich-Kwong EoS and the CoolProp fluid database (open source) were compared in a preliminary study. After that, the models have been included through user-defined functions (UDFs) in ANSYS Fluent and were tested on 3D CFD calculations of a twin screw expander and a simplified expansion model. Several performance indicators such as mass flow rates, pressure-volume diagrams and power output are used to compare different fluid models for R245fa. From the results of this study, it can be concluded that the ideal gas EoS shows big deviations going closer to the saturation vapor line and the deviation in power comparing to the Aungier Redlich-Kwong EoS is around 8%. Conversely, the Aungier Redlich-Kwong EoS and the CoolProp database present very similar results for this case.

scholarly journals Utilization of the Exhaust Gas of a Gas Pipeline Compression Station to Generate Electricity

2017 ◽  
pp. 573-583
Author(s):  
Ehsan Amirabedin ◽  
M. Zeki Yilmazoglu ◽  
Ali Durmaz
Keyword(s):  
Natural Gas ◽  
Gas Turbine ◽  
Energy Savings ◽  
Waste Heat ◽  
Organic Rankine Cycle ◽  
Cost Savings ◽  
Transportation Cost ◽  
Working Fluid ◽  
Exhaust Gas ◽  
Gas Compression

In this study, an application of an Organic Rankine Cycle (ORC) in a natural gas compression station in Erzincan region is presented. Natural gas compression station (NGCS) uses a gas turbine to pressurize the natural gas for transportation. Waste heat of gas turbine can be utilized by an ORC which uses n-pentane as working fluid to generate electricity. A costs/advantages analysis of the implementation is performed. According to designing factors, the pressure of the natural gas at the inlet and outlet of the NGCS are 48 bar and 73 barrespectively. Mass flow rate and temperature of the exhaust gas from the GT are 26.65 kg/s and 460°C respectively and it shows that a significant amount of heat is rejected to the ambient. By applying an ORC to the NGCS, the results show that; total gross power via organic turbine, annual energy savings and annual cost savings are 1,385 kW, 11,057,535 kWhr and 1,327,000 $ respectively. Furthermore the payback time is calculated 3.77 years. Generally in this study, by utilizing an ORC in a NGCS, it has been tried to reduce the transportation cost and environmental impact of NG transportation.

Solution behavior of quenched or strongly charged polyampholytes in aqueous-salt solutions

2019 ◽  
Vol 94 (2) ◽  
pp. 35-44 ◽  
Author(s):  
G. Toleutay ◽  
◽  
A.V. Shakhvorostov ◽  
S.K. Kabdrakhmanova ◽  
S.E. Kudaibergenov ◽  
...  
Keyword(s):  
Salt Solutions ◽  
Solution Behavior ◽  
Aqueous Salt Solutions

scholarly journals Component-Oriented Modeling of a Micro-Scale Organic Rankine Cycle System for Waste Heat Recovery Applications

2021 ◽  
Vol 11 (5) ◽  
pp. 1984
Author(s):  
Ramin Moradi ◽  
Emanuele Habib ◽  
Enrico Bocci ◽  
Luca Cioccolanti
Keyword(s):  
Electric Power ◽  
Heat Recovery ◽  
Waste Heat Recovery ◽  
Waste Heat ◽  
Organic Rankine Cycle ◽  
Rankine Cycle ◽  
Operating Conditions ◽  
Working Fluid ◽  
Pump Efficiency ◽  
Micro Scale

Organic Rankine cycle (ORC) systems are some of the most suitable technologies to produce electricity from low-temperature waste heat. In this study, a non-regenerative, micro-scale ORC system was tested in off-design conditions using R134a as the working fluid. The experimental data were then used to tune the semi-empirical models of the main components of the system. Eventually, the models were used in a component-oriented system solver to map the system electric performance at varying operating conditions. The analysis highlighted the non-negligible impact of the plunger pump on the system performance Indeed, the experimental results showed that the low pump efficiency in the investigated operating range can lead to negative net electric power in some working conditions. For most data points, the expander and the pump isentropic efficiencies are found in the approximate ranges of 35% to 55% and 17% to 34%, respectively. Furthermore, the maximum net electric power was about 200 W with a net electric efficiency of about 1.2%, thus also stressing the importance of a proper selection of the pump for waste heat recovery applications.

scholarly journals Organic Rankine cycle for turboprop engine application

2021 ◽  
pp. 1-21
Author(s):  
G.E. Pateropoulos ◽  
T.G. Efstathiadis ◽  
A.I. Kalfas
Keyword(s):  
Waste Heat ◽  
Organic Rankine Cycle ◽  
Weight Ratio ◽  
Rankine Cycle ◽  
Aircraft Engine ◽  
Working Fluid ◽  
Engine Fuel ◽  
Exhaust Gases ◽  
Waste Heat Recovery System ◽  
Turboprop Engine

ABSTRACT The potential to recover waste heat from the exhaust gases of a turboprop engine and produce useful work through an Organic Rankine Cycle (ORC) is investigated. A thermodynamic analysis of the engine’s Brayton cycle is derived to determine the heat source available for exploitation. The aim is to use the aircraft engine fuel as the working fluid of the organic Rankine cycle in order to reduce the extra weight of the waste heat recovery system and keep the thrust-to-weight ratio as high as possible. A surrogate fuel with thermophysical properties similar to aviation gas turbine fuel is used for the ORC simulation. The evaporator design as well as the weight minimisation and safety of the suggested application are the most crucial aspects determining the feasibility of the proposed concept. The results show that there is potential in the exhaust gases to produce up to 50kW of power, corresponding to a 10.1% improvement of the overall thermal efficiency of the engine.

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