Dynamic simulation and power output of small scale solar based organic Rankine cycle with thermal storage system

2019 ◽  
Vol 67 (5) ◽  
pp. 44-52
Author(s):  
Suresh Baral
Keyword(s):  
Dynamic Simulation ◽  
Power Output ◽  
Storage System ◽  
Organic Rankine Cycle ◽  
Rankine Cycle ◽  
Thermal Storage ◽  
Small Scale

scholarly journals Comparative Analysis of Small-Scale Organic Rankine Cycle Systems for Solar Energy Utilisation

Energies ◽  
2019 ◽  
Vol 12 (5) ◽  
pp. 829 ◽  
Author(s):  
Ruiqi Wang ◽  
Long Jiang ◽  
Zhiwei Ma ◽  
Abigail Gonzalez-Diaz ◽  
Yaodong Wang ◽  
...  
Keyword(s):  
Solar Energy ◽  
Power Output ◽  
Organic Rankine Cycle ◽  
Rankine Cycle ◽  
Hot Water ◽  
Superior Performance ◽  
Small Scale ◽  
Water Storage Tank ◽  
Solar Thermal Collector ◽  
Cycle Systems

Small-scale organic Rankine cycle (ORC) systems driven by solar energy are compared in this paper, which aims to explore the potential of power generation for domestic utilisation. A solar thermal collector was used as the heat source for a hot water storage tank. Thermal performance was then evaluated in terms of both the conventional ORC and an ORC using thermal driven pump (TDP). It is established that the solar ORC using TDP has a superior performance to the conventional ORC under most working conditions. Results demonstrate that power output of the ORC using TDP ranges from 72 W to 82 W with the increase of evaporating temperature, which shows an improvement of up to 3.3% at a 100 °C evaporating temperature when compared with the power output of the conventional ORC. Energy and exergy efficiencies of the ORC using TDP increase from 11.3% to 12.6% and from 45.8% to 51.3% when the evaporating temperature increases from 75 °C to 100 °C. The efficiency of the ORC using TDP is improved by up to 3.27%. Additionally, the exergy destruction using TDP can be reduced in the evaporator and condenser. The highest exergy efficiency in the evaporator is 96.9%, an improvement of 62% in comparison with that of the conventional ORC, i.e., 59.9%. Thus, the small-scale solar ORC system using TDP is more promising for household application.

scholarly journals Solar Salt Latent Heat Thermal Storage for a Small Solar Organic Rankine Cycle Plant

2018 ◽  
Author(s):  
Sol-Carolina Costa ◽  
Khamid Mahkamov ◽  
Murat Kenisarin ◽  
Kevin Lynn ◽  
Elvedin Halimic ◽  
...  
Keyword(s):  
Heat Pipe ◽  
Latent Heat ◽  
Storage System ◽  
Organic Rankine Cycle ◽  
Heat Pipes ◽  
Rankine Cycle ◽  
Thermal Storage ◽  
Working Fluid ◽  
External Diameter ◽  
Solar Salt

The design of the Latent Heat Thermal Storage System (LHTESS) was developed with thermal capacity of about 100 kWh as a part of small solar plant, based on the Organic Rankine Cycle (ORC). The phase change material (PCM) used is Solar salt with the melting/solidification temperature of about 220°C. Thermo-physical properties of the PCM were measured, including its phase transition temperature, heat of fusion, specific heat and thermal conductivity. The design of the thermal storage was finalized by means of the 3-D CFD analysis. The thermal storage system is made of six rectangular boxes with dimensions of 1 m (width) × 0.66 m (height) × 0.47 m (depth). The thermal energy is delivered to each of the thermal storage boxes with the use of thermal oil, heated by Fresnel mirrors. The heat is transferred into and from the PCM in the box using 40 bi-directional heat pipes with the external diameter of about 12 mm. The length of the heat pipe in the PCM box is 430 mm and it is placed in the cylindrical metallic protection cartridge, installed in the thermal storage vessel. The working fluid in the heat pipe is water. A set of metallic screens are installed in the box with the pitch of 8–10 mm to enhance the heat transfer from heat pipes to the PCM and vice-versa during the charging and discharging processes, which take about 4 hours. The one unit of the described thermal storage system is undergoing the laboratory tests. Preliminary results demonstrate that the performance of the thermal storage is in a good agreement with numerical predictions. After completion of final design modifications, all units will be assembled at the plant’s demonstration site and tested with the ORC turbine.

scholarly journals Dynamic Modeling and Control System Definition for a Micro-CSP Plant Coupled With Thermal Storage Unit

2014 ◽  
Author(s):  
Melissa K. Ireland ◽  
Matthew S. Orosz ◽  
J. G. Brisson ◽  
Adriano Desideri ◽  
Sylvain Quoilin
Keyword(s):  
Rural Communities ◽  
Organic Rankine Cycle ◽  
Rankine Cycle ◽  
Thermal Storage ◽  
Energy Coupling ◽  
Operating Conditions ◽  
Small Scale ◽  
Storage Unit ◽  
Modeling And Control ◽  
The Impact

Organic Rankine cycle (ORC) systems are gaining ground as a means of effectively providing sustainable energy. Coupling small-scale ORCs powered by scroll expander-generators with solar thermal collectors and storage can provide combined heat and power to underserved rural communities. Simulation of such systems is instrumental in optimizing their control strategy. However, most models developed so far operate at steady-state or focus either on ORC or on storage dynamics. In this work, a model for the dynamics of the solar ORC system is developed to evaluate the impact of variable heat sources and sinks, thermal storage, and the variable loads associated with distributed generation. This model is then used to assess control schemes that adjust operating conditions for daily environmental variation.

scholarly journals Solar Salt Latent Heat Thermal Storage for a Small Solar Organic Rankine Cycle Plant

2019 ◽  
Vol 142 (3) ◽  
Author(s):  
Sol-Carolina Costa ◽  
Khamid Mahkamov ◽  
Murat Kenisarin ◽  
Mohammad Ismail ◽  
Kevin Lynn ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Latent Heat ◽  
Storage System ◽  
Organic Rankine Cycle ◽  
Heat Pipes ◽  
Rankine Cycle ◽  
Thermal Storage ◽  
Thermal Bonding ◽  
Solar Salt ◽  
Computational Fluid Dynamics Analysis

Abstract The design of the latent heat thermal storage system (LHTESS) was developed with a thermal capacity of about 100 kW h as a part of small solar plant based on the organic Rankine cycle (ORC). The phase change material (PCM) used is solar salt with the melting/solidification temperature of about 220 °C. Thermophysical properties of the PCM were measured, including its phase transition temperature, heat of fusion, specific heat, and thermal conductivity. The design of the thermal storage was finalized by means of the 3D computational fluid dynamics analysis. The thermal storage system is modular, and the thermal energy is delivered with the use of thermal oil, heated by Fresnel mirrors. The heat is transferred into and from the PCM in the casing using bidirectional heat pipes, filled with water. A set of metallic screens are installed in the box with the pitch of 8–10 mm to enhance the heat transfer from heat pipes to the PCM and vice-versa during the charging and discharging processes, which take about 4 h. This work presents a numerical study on the use of metallic fins without thermal bonding as a heat transfer enhancement method for the solar salt LHTESS. The results show that the absence of the thermal bonding between fins and heat pipes (there was a gap of 0.5 mm between them) did not result in a significant reduction of charging or discharging periods. As expected, aluminum fins provide better performance in comparison with steel ones due to the difference in the material conductivity. The main advantage observed for the case of using aluminum fins was the lower temperature gradient across the LHTESS.

Efficiency Enhancement of a Small Scale Closed Solar Thermal Brayton Cycle by a Combined Simple Organic Rankine Cycle

2012 ◽  
Author(s):  
H. Riazi ◽  
N. A. Ahmed
Keyword(s):  
Power Output ◽  
Organic Rankine Cycle ◽  
Rankine Cycle ◽  
Solar Thermal ◽  
Small Scale ◽  
Brayton Cycle ◽  
Efficiency Enhancement ◽  
Power Cycles ◽  
Micro Turbine ◽  
Net Power Output

In this paper efficiency enhancement of a small scale closed solar thermal Brayton cycle is investigated by combining it to a simple organic Rankine cycle. Brayton power cycles are generally known as the enabling technology for high temperature solar power towers due to their higher efficiencies compared to other power cycles. Unlike conventional solar-thermal plants, which concentrate the sun’s energy to generate steam for driving a turbine, the Brayton thermodynamic does not use water. Instead, the concentrated solar energy is used to heat compressed air, which then expands through a gas turbine to generate power. Irreversible loss in compressor and turbine, the operating temperature of solar collector and recuperator effectiveness are the main features that limit the net power output of the system which should be considered and analyzed. The exhaust of the gas turbine is still at high temperature that should be cooled down before entering the compressor. Thus, this heat can be utilized to operate a low temperature Rankine cycle and increase the system efficiency and power generation. Operating points of off the shelf micro-turbines and steam turbine with parabolic solar dish concentrator of various concentrating ratios are considered. Thermodynamic analysis is applied, by using the first and second law of thermodynamics, to obtain the optimum temperature of solar collector, minimum irreversibility rates to maximize the efficiency and net power output of the system at various steady-state conditions. Results show that for the closed solar thermal Brayton cycle the maximum overall first law efficiency of the system can be increased of more than 5% by combining a simple Rankine cycle to recover the exhaust heat and a significant 20% increase in the second law efficicency. The system efficiency is related to the solar concentration ratio with an optimum operating temperature and the choice of micro-turbine. On this basis, both the overall efficiency and the total output power may reach their maximum value by optimizing the pressure ratio. In a small scale closed solar thermal Brayton cycle combined by a Rankine cycle with a micro turbine operating at its highest compressor efficiency, the operating conditions can be optimized in such a way that the system produces maximum net power output or having the highest overall efficiency.

scholarly journals Thermodynamic Performance Analysis of Solar Based Organic Rankine Cycle Coupled with Thermal Storage for a Semi-Arid Climate

Machines ◽  
2021 ◽  
Vol 9 (5) ◽  
pp. 88
Author(s):  
Nasser Mohammed A. Almefreji ◽  
Babras Khan ◽  
Man-Hoe Kim
Keyword(s):  
Performance Analysis ◽  
Solar Radiation ◽  
Power Output ◽  
Thermal Efficiency ◽  
Organic Rankine Cycle ◽  
Rankine Cycle ◽  
Thermal Storage ◽  
Moderate Temperature ◽  
Thermodynamic Performance ◽  
Net Power Output

This study focuses on the thermodynamic performance analysis of the solar organic Rankine cycle (SORC) that uses solar radiation over a moderate temperature range. A compound parabolic collector (CPC) was adjusted to collect solar radiation because of its long-lasting nature and featured low concentration ratios, which are favorable for moderate temperature applications. A thermal storage tank was fixed to preserve the solar energy and ensure the system’s continuous performance during unfavorable weather. However, water was used as the heat transfer fluid and R245fa was used as the working fluid in this system. The performance in both the hottest and coldest months was analyzed using the average hourly profile in MATLAB using weather data from Riyadh, Saudi Arabia. Variations in the tank temperature during the charging and discharging modes were found. The hourly based thermal efficiency and net power output for both configurations were also compared. The results show that at 17:00, when the cycle was about to shut down, the thermal efficiency was 12.79% and the network output was 16 kW in July, whereas in January, the efficiency was ~12.80% and the net power output was 15.54 kW.

scholarly journals Energy, exergy, and environmental assessment of a small-scale solar organic Rankine cycle using different organic fluids

Heliyon ◽  
2021 ◽  
Vol 7 (9) ◽  
pp. e07947
Author(s):  
Geanette Polanco Piñerez ◽  
Guillermo Valencia Ochoa ◽  
Jorge Duarte-Forero
Keyword(s):  
Environmental Assessment ◽  
Organic Rankine Cycle ◽  
Rankine Cycle ◽  
Small Scale ◽  
Organic Fluids
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