Solar Organic Rankine Cycle Research Articles

Dynamic performance analysis and optimization research on solar dual-stage evaporation multigeneration system

A novel solar dual-stage evaporation multigeneration system is proposed, with analysis on the impact of the parabolic trough collector area (APTC) and the volume of the heat storage tank (VHST) on performance under dynamic conditions. The particle swarm optimization- genetic algorithm and the minimum path method optimized the system’s overall performance. Results show that reducing APTC and increasing VHST can enhance energy performance within a certain range, but beyond specific thresholds, changes in APTC and VHST no longer affect it. As APTC and VHST increase, economic performance initially improves but then declines. The particle swarm optimization- genetic algorithm increased optimization efficiency and avoided local optima. When using the minimum path method, the dimensionless cumulative error was 0.63, balancing thermal and economic performance. Using toluene as the working fluid, the optimized system achieved thermal and exergy efficiencies of 56.06 % and 9.15 %, respectively, with a net present value of 58.12 M$, a payback period of 5.23 years, and an equivalent CO2 reduction of 24.8 kt, outperforming the solar organic Rankine cycle system in energy efficiency, economic performance, and carbon reduction potential. The solar dual-stage evaporation multigeneration system achieved the best performance with toluene as the working fluid, while heptane provided longer running time and greater carbon reduction potential. At low rated power generation, performance differences between toluene and heptane were minimal, while as the rated power generation increased, toluene showed significant advantages in thermal and economic performance.

A 4E Analysis of a Solar Organic Rankine Cycle Applied to a Paint Shop in the Automotive Industry

In a conventional automotive manufacturing plant, the paint shop alone can represent 36% of the total energy consumption, making it the most demanding area in terms of electricity and fossil fuel energy consumption. This study explores the possibility of decentralizing the production of electrical power and heat simultaneously, using an Organic Rankine Cycle (ORC) system integrated with a Parabolic Trough Collector (PTC) in a paint shop. To date, no similar system has been explored or implemented by the automotive industry. To increase the efficiency of the integrated system, wasted heat generated during the paint manufacturing process is recovered and used to pre-heat the organic fluid in the ORC system. A 4E analysis (Energy, Exergy, Economic, and Environmental) is conducted to determine the practical viability of the proposed system. When applied to the southern region of the USA, this system’s installed capacity is projected to be 11 times higher than the two unique SORC pieces of equipment currently running in Louisiana and Florida. The goals are to reduce the reliance on external primary energy sources and decrease the carbon emission footprint from production activity. The system is evaluated for a location in Alabama, USA. The designed SORC, using toluene, can produce 712.2 kWel net and 13,132 kg/h of hot water, with an overall energy efficiency of 31.02%; exergy efficiency of 34.23; and ORC efficiency of 27.70%. This leads to an electrical energy saving of 5.9% for the manufacturing plant. The regenerative thermal oxidizer (RTO) heat exchanger, the secondary heat source of the system, has the highest exergy destruction—3583 kW. The system avoids the emission of 4521 tCO2 per year. A payback period of 10.16 years for the proposed system is estimated. Considering a planning horizon of 10 years, the investment in the system is also justified by a benefit–cost analysis.

Practicality and Economic Assessment on Using the Solar Organic Rankine Cycle as a Power Source for a Specific Membrane-based Desalination System

Practicality and Economic Assessment on Using the Solar Organic Rankine Cycle as a Power Source for a Specific Membrane-based Desalination System

Performance Evaluation and Working Fluid Screening of Direct Vapor Generation for Solar ORC Using Low-Global Warming Potential (GWP) Working Fluids

Traditional working fluids used in direct vapor generation for solar organic Rankine cycle (DVG-ORC) systems have a high global warming potential (GWP), making it imperative to find environmentally friendly alternative working fluids for these systems. This paper evaluates the performance of the DVG-ORC system under different operating conditions. By comparing the results of traditional working fluids with those of low-GWP fluids, the feasibility of using low-GWP fluids as alternative working fluids is explored. Additionally, to screen the working fluids suitable for this system further, the system is optimized with net output power as the objective function. The results show that evaporation temperature has different impacts on system performance. R245ca and R1336mzz(Z) exhibit higher net output power at different evaporation temperatures, with R1336mzz(Z) only reducing it by 3.73–5.26% compared to R245ca. However, an increase in condensation temperature negatively affects system performance, leading to a decrease in net output power and various efficiencies. Net output power increases with an increase in mass flow rate, indicating that higher mass flow rates can enhance system performance. The optimization results show that the net output power of low-GWP working fluid R1336mzz(Z) decreases by only 3.44% compared to R245ca, which achieves the maximum net output power. Moreover, among low-GWP working fluids, R1336mzz(Z) demonstrates the highest ORC efficiency and system efficiency, making it the most suitable working fluid for the DVG-ORC system due to its environmental friendliness and safety.

Performance Optimization and Techno-Economic Analysis of an Organic Rankine Cycle Powered by Solar Energy

Abstract To improve the performance of traditional solar power generation systems, a new solar organic Rankine cycle system that can generate electricity and heat is proposed. The system incorporates the separation-flash process, regenerator, and ejector to enhance its efficiency. The optimization of the working fluid, pinch point temperature difference, evaporator outlet dryness, flash dryness, and entrainment ratio is conducted to achieve optimal performance. Aiming at maximum exergy efficiency and minimum levelized energy cost, the operating parameters are further optimized using a multi-objective optimization algorithm. R245fa is the optimal working fluid for the system, offering maximum net output power and thermal efficiency. The optimal performance can be achieved when the pinch point temperature difference is 1 K, evaporator outlet dryness is 0.6, flash dryness is 0.44, and entrainment ratio is 0.29. Moreover, the photovoltaic subsystem can further increase the net output power and thermal efficiency by 15.52% and 15.45%, achieving a maximum net output power and thermal efficiency of 33.95 kW and 10.61%. Additionally, when the solar hot water temperature is 100 °C, pinch point temperature difference is 1.8 K, evaporator outlet dryness is 0.6, flash dryness is 0.65, and entrainment ratio is 0.16, the system can achieve the optimal state of both performance and economy, exhibiting an optimal exergy efficiency and levelized energy cost of 64.1% and 0.294 $/kWh, respectively. Finally, the payback period of system is 3.43 years, indicating the potential for significant economic benefits.

Impact of turbine characteristics on low temperature organic Rankine cycles operating with zeotropic and azeotropic mixtures

The urgent need to mitigate the environmental impacts of fossil fuel combustion has spurred interest in renewable energy sources for electricity generation, particularly solar organic Rankine cycles (ORCs). This study investigates the potential of fluid mixtures in low-temperature ORCs, focusing on a radial turbine. While fluid mixtures have shown promise for heat recovery in low-temperature applications, previous research often overlooked turbine characteristics by assuming constant efficiencies. This study set out to examine the impact of turbine characteristics on the ORC performance when adapting fluid mixtures by coupling a cycle-turbine model incorporated with real gas analysis. The outcomes of the turbine model are exported to the cycle model to evaluate its performance. Results reveal significant variations in cycle performance due to turbine power and efficiency, outweighing the effects of temperature glide in fluid mixtures. Although fluid mixtures enhance thermal compatibility with heat sources, certain pure fluids exhibit superior cycle performance owing to better turbine characteristics. Moreover, the assumption of constant turbine efficiency compromises result accuracy by up to 45 % compared to dynamic turbine efficiency. Notably, the isobutane/isopentane mixture (0.7/0.3) emerges as the most favourable, achieving a turbine power of 48.90 kW, turbine efficiency of 71 %, and thermal efficiency of 12.29 %.

Thermodynamic analysis of an evacuated tube solar collector system for industrial building application: A case study

In this study, a modified solar-Organic Rankine Cycle (ORC) assisted hydrogen production system for two different scenarios was experimentally investigated. In the study, evacuated tube solar collector (ETSC), ORC system, proton exchanger membrane electrolyzer (PEMe) unit is discussed with a holistic perspective. The presented work includes energy and exergy analysis of solar-ORC assisted hydrogen production. According to scenario 1 (S-1), only the case of hydrogen production from the installed system is considered. According to Scenario 2 (S-2), the both electrical energy and hydrogen production from the installed system is examined. As a result of the study, the energy efficiency in S-1 and S-2 operating modes was calculated as 9.553% and 16.02%, respectively. Additionally, the highest exergy efficiency for both scenarios was calculated as 6.129% in the S-2 scenario. Furthermore, hydrogen production amount of the S-1 and S-2 scenarios was calculated as 743.1 kg/annual and 371.5 kg/annual, respectively.

Thermal performance study of a solar-coupled phase changes thermal energy storage system for ORC power generation

The current solar organic Rankine cycle power generation (ORC) system cannot run smoothly under the design conditions due to the shortcomings of solar fluctuations, and thermal energy storage (TES) can effectively buffer the fluctuations of solar energy. Cascaded heat storage (CLTES) has been shown to be more suitable for solar heat storage than single-stage heat storage (LTES). The main objective of this study is to analyze the thermal storage characteristics of thermal storage systems under real-time solar energy fluctuations, and to improve the thermal storage efficiency and total thermal storage capacity of solar phase change thermal storage systems in distributed scenarios. The current research on solar CLTES system needs to focus on the heat storage characteristics under the actual solar fluctuations to provide guidance for the design and practical operation of CLTES system. Analyzing the effect of solar fluctuations on thermal storage performance is the focus of solar thermal storage research, which can provide guidance for the design and actual operation of CLTES systems. However, the current research on solar CLTES system lacks the analysis of thermal storage characteristics under typical solar energy fluctuations. Therefore, a simplified two-dimensional enthalpy-dynamic model of heat transfer for shell-and-tube latent heat storage system is developed in this paper to simulate the heat storage characteristics of single-stage and cascade heat accumulators containing different phase change materials (PCMs) at a fixed temperature of the heat source, and the heat storage performance of the system is simulated based on the solar fluctuations of typical four seasons. Finally, based on the shortcomings of large-capacity thermal storage, a dual-tank recirculation thermal storage model is proposed and the thermal storage characteristics of the improved recirculation model are analyzed. The results show that the optimized cycle heat storage mode can bring about a minimum of 10 % and a maximum of 17.2 % thermal efficiency improvement. On a typical summer day with the most abundant solar energy resources, four times of complete phase change heat storage and one incomplete phase change heat storage were completed (melting fraction = 81.83 %), and on a typical winter day with the least solar energy resources, two times of complete phase change heat storage and one incomplete phase change heat storage were completed (melting fraction = 75.81 %). The maximum difference of heat storage between them is 45.38 %.

Thermodynamic Analysis of Solar Organic Rankine Cycle Using Evacuated Tubular Collector

This study investigates the affecting parameters for the thermal performance of a Solar Organic Rankine Cycle. The thermodynamic analysis covers the research on the effects of the following parameters: the pressure and temperature of the working fluid at the turbine entrance, and the turbine and pump isentropic efficiencies. The solar organic Rankine cycle is analyzed for an evacuated tubular solar collector. The required collector area for both a fixed value (0.8) of solar fraction and several source (solar collector output) temperatures is also determined for different months of the year in the study. The computer software of Engineering Equation Solver (EES) is used to construct the mathematical model of the cycle and to perform the thermodynamic analysis of the system. In the analysis, R123 and R600 organic fluids are used, and a comparison is made between the two fluids in terms of their effects on the system performance. The results show that R600 has better performance characteristics than R123. The results also show that the system efficiency decreases with increasing temperature at turbine entrance, but with decreasing pressure at turbine entrance. The turbine efficiency influences the system thermal efficiency significantly while the pump efficiency does not have a significant effect on the system thermal efficiency.

The theoretical approach of the solar organic Rankine cycle integrated with phase change material for the Hungarian region

AbstractHungary is not only dependent on imports of natural gas and fossil fuels, but Hungary is also the lowest in renewable energy utilization; otherwise, only 11.3% compared to other Central European countries in renewable energy utilization, above 13%. The percentage of renewables in power generation quadrupled from 8% to 16% between 2010 and 2020, with most of the gains coming from the rapid expansion of solar energy, particularly after 2016. Regarding solar energy resource potential, Hungary has a daily total of around 3.2–3.6 kWh/m2 and a yearly total of about 1168–1314 kW.h/m2. This makes it a suitable location for putting solar thermal collectors in conjunction with an organic Rankine cycle (ORC) system. In this study, the authors analyzed solar thermal as a heat source to generate electricity with ORC using two types of working fluids (R245fa and R123). Hungary's weather data for a whole year is used as primary data to look for solar radiation characteristics and ambient temperature. Based on the general solar collector equation, the parabolic tube collector was selected as the best solar collector to utilize solar radiation by producing a maximum heat of around 654.68 kW. Therefore, the evacuated flat plate collector was selected as the solar collector that can produce the maximum outlet temperature of around 372.15 K with a similar size aperture area. Producing a temperature output from the solar collector for heat transfer in the ORC system and from the performance showed that R245fa resulted in better Wnet performance compared with R123 with values of 45.82 and 28.17 kW, respectively, under the same solar collector. Meanwhile, the material suitable for the thermal energy storage‐evaporator combination is organic phase change material using N‐Octacosane, which in the same temperature range (350–375 K) has the smallest ζ(T) value (1.08–1.103), so the mass required for the system is very efficient.

Thermodynamic analysis of a hybrid energy system coupling solar organic Rankine cycle and ground source heat pump: Exploring heat cascade utilization

The demand for efficient utilization of renewable energy is growing and the hybrid energy system driven by solar and geothermal energy is a significant way to achieve carbon neutrality. This paper presents a hybrid energy system coupling solar organic Rankine cycle (S-ORC) with ground source heat pump (GSHP) for heating and power supply to explore the heat cascade utilization. In the hybrid energy system, the ground heat exchanger (GHE) is shared by the S-ORC and GSHP systems and the waste heat from the condenser of S-ORC is recovered to enhance the coefficient of performance (COP) of GSHP. A mathematical model is optimized to analyze the parametric effects on thermodynamic performance. The results indicate that the COP of the hybrid energy system can be improved up to 6.5 which shows the obvious advantage compared to 2.8 of the stand-alone GSHP system. Furthermore, the hybrid energy system can obtain optimum exergy efficiency by matching ground source temperature and condensation temperature in the ORC unit. For a building of 3000 m2 with heating and power supply, multi-objective optimization is carried out to obtain the optimal design performance that the net power output, thermal efficiency and exergy efficiency are 180.0 kW, 27.5%, and 9.2% respectively.

Optimizing Solar Energy Harvesting through Integrated Organic Rankine Cycle–Reverse Osmosis Systems: A Techno–Economic Analysis

When it comes to seawater desalination in the small- to medium-electricity ranges, the organic Rankine cycle (ORC) powered by solar energy stands out as the most energy-efficient technology currently available. Various solar techniques have been developed to capture and absorb solar energy. Among them, the parabolic trough collector (PTC) has gained recognition as a low-cost solar thermal collector with a long operating life. This study investigates the thermodynamic performance and economic parameters of a PTC-powered ORC using Dowtherm A and toluene as working fluids for the solar cycle and ORC cycle, respectively. Thermo-economic multi-objective optimization and decision-making techniques are applied to assess the system’s performance. Four key parameters are analyzed for their impact on exergy efficiency and total hourly cost. Using TOPSIS decision-making, the best solution from the Pareto frontier is identified, featuring an ORC exergy efficiency of 30.39% and a total hourly cost of 39.38 US$/h. The system parameters include a mass flow rate of fresh water at 137.7 m3/h, a total output net power of 577.9 kJ/kg, and a district heating supply of 1074 kJ/kg. The cost analysis reveals that the solar collector represents approximately 68% of the total hourly cost at 26.77 US$/h, followed by the turbine, thermoelectric generator, and reverse osmosis (RO) unit.

Comparison Of The Electricity Generation Potentials Of Solar ORC Designed With Different Fluids Depending On Instantaneous Solar Radiation In Four Districts Of Türkiye

In this study, the solar Organic Rankine Cycle (ORC) system was analyzed to meet some of the electrical energy needed in large and medium-sized buildings and large enterprises such as hotels from solar energy. A simulation study was conducted for different districts in Türkiye that are rich in solar energy potential. These counties and the provinces they are affiliated with; Silifke-İçel, Alanya-Antalya, Bodrum-Muğla, Çeşme-İzmir. The power value transferred to the ORC was determined by considering the instantaneous radiation values and sunshine durations for the districts. The performance of solar ORC was determined by comparing fluids from three different organic fluid types. Organic fluids and types used in design; benzene-aromatic hydrocarbon, cyclohexane-alkane, octamethylcyclotetrasiloxane (D4)-siloxane. Considering the maximum electrical energy values obtained from Solar ORC in the summer months, it was seen that 205 MWh electricity generated was obtained for Silifke with benzene at a heat source temperature of 223 oC in July. Maximum solar parabolic trough collector (PTC) specific electric power value was determined as 59.52 W/m2 in Alanya district with benzene in June. When the four districts are evaluated together, it has been determined that benzene performs better than cyclohexane by 3.8% on average and 23% better than D4. When the annual electrical energy values are examined, the highest production was determined as 1625 MWh with benzene fluid in Alanya district.

Energy and exergy analysis of waste heat recovery from pressurized hot smothering steel slag by solar organic Rankine cycle

Energy and exergy analysis of waste heat recovery from pressurized hot smothering steel slag by solar organic Rankine cycle

Hydrogen production via renewable-based energy system: Thermoeconomic assessment and Long Short-Term Memory (LSTM) optimization approach

A clean and carbon-free energy market can be more sustainable and safer that can be approaches by investing on hydrogen energy. Further, a renewable energy-driven energy production cycle coupled with an energy storage option is of major significance. In the present article, a hybrid process based on geothermal and solar energies is conceptually designed and simulated. The process is comprised of a solar-organic Rankine cycle (ORC) unit, a geothermal cycle, an electrolysis unit (based on alkaline electrolyzer stack, AES), and a nanomaterial-based unit (i.e., alkaline fuel cell stack, AFC) to store hydrogen. Combining nickel nanoparticles thermally enclosed in multiwalled carbon nanotubes (MWCNTs) with a composite thermoset anion-exchange membrane enables alkaline water splitting. When the grid demands are less than generated electricity rate, additional electricity is fed into an AES to generate hydrogen fuel. Further, when the grid demands are more than generated electricity rate, stored hydrogen and oxygen are fed into an AFC to back convert the chemical energy in the fuel into electrical energy. The thermodynamic and thermo-economic evaluations of the considered hybrid process are comprehensively presented. Furthermore, multi-objective optimization of the introduced process has been developed in accordance with the genetic optimization technique to maximize the rate of electricity and minimize the cost rate. Additionally, the Long Short-Term Memory (LSTM) -based optimization technique is established and discussed. The outcomes indicated that under the LSTM-based genetic optimization technique the output electricity and electricity and hydrogen costs of the considered hybrid process can be improved by 34.55% and reduced by 40.3% and 26.8%, respectively. It was also found that the estimations obtained from the LSTM technique are very reliable, and can be relied on with acceptable accuracy. The estimation based on LSTM has an accuracy level of more than 98.1%.

A novel solar-driven Organic Rankine Cycle system based on the two-stage solar thermal collection and accumulation

Solar thermal power has attracted much attention because it is instrumental to solar energy storage and power grid peak shaving. Among the various solar thermal power technologies, the Organic Rankine Cycle stands out as a prevalent choice for low and intermediate-temperature (80 – 200 °C) solar thermal power generation applications. However, it is required of the concentrating solar collectors for medium temperature supply and its performance is greatly affected by the off-design operation owing to variable solar irradiance. In this paper, a novel solar-driven Organic Rankine Cycle system that consists of a two-stage solar thermal collection and accumulation design is proposed to solve the above issues. Two-stage non-concentrating solar plants are adopted to harvest global solar irradiance and regulate system operation. Two-stage energy accumulators can not only mitigate the influence of the solar irradiance fluctuation on the Organic Rankine Cycle off-design running but also enhance the temperature drop of thermal energy storage. Through the experimental test and numerical simulation, the results indicate that the influence of solar irradiance on the Organic Rankine Cycle steady operation has been weakened (reducing power output fluctuation range by approximately 70%), and the overall system efficiency has also been improved by 43.85%. Consequently, the solar Organic Rankine Cycle system proposed in this paper exhibits superior thermal performance compared to the conventional systems and is conducive to the advancement of the non-concentrating solar thermal power system.

Performance Analysis and Comprehensive Evaluation of Solar Organic Rankine Cycle Combined with Transcritical CO2 Refrigeration Cycle

In order to achieve efficient utilization of solar energy resources, this study combines the trans-critical organic Rankine cycle (ORC) power cycle (TORC) with the trans-critical CO2 refrigeration cycle (TCO2). Additionally, a comprehensive three-level index decision evaluation system is developed based on system safety and environmental protection, thermodynamics, and techno-economic performance. The evaluation focuses on typical medium- and high-temperature solar energy applications and considers six organic working gases. The evaluation results demonstrate that the R600 + CO2 solution outperformed the others. This solution achieved a maximum net output power (Pnet) of 1531.31 kW and 2306.43 kW, a maximum coefficient of performance (COP) of 3.16, a predicted payback period of 2.651 years and 2.033 years, and a benefit–investment ratio of 4.533 and 5.773.

Assessment of thermodynamic performance of a novelty solar-ORC configuration based hydrogen production: An experimental study

In this study, a solar-Organic Rankine Cycle (ORC) assisted hydrogen production system was experimentally investigated. An evacuated tube heat pipe solar collector (ETHPSC) was used for thermal energy generation. The tubes used in this study were produced differently from the tubes of the conventional heat pipe. The condenser area of the vacuum tubes used was made of glass instead of copper. Moreover, acetone was used as the fluid in the tube. The thermal energy obtained from the collector was used as a heat source for electrical energy in the ORC system. A uniquely designed ORC system is modeled and manufactured. The electrical energy obtained from the ORC unit was used for hydrogen production by means of the proton exchange membrane electrolyzer (PEMe). As a result of the study, two different efficiency analyses were made. If all of the electricity produced in the S-1 scenario was spend on hydrogen production, the energy and exergy efficiency were calculated as 3.45% and 2.15%, respectively. In the S-2 scenario, if some of the electricity produced was spend on hydrogen production, the energy and exergy efficiency of the whole system were found to be 0.01446% and 0.002146% respectively. In addition, 0.000004433 kg/s hydrogen production was obtained from the presented system.

Development of an automated design and off-design radial turbine model for solar organic Rankine cycle coupled to a parabolic trough solar collector

Most of solar organic Rankine cycle (ORC) studies treat expansion machines as ideal machines operating with constant efficiencies. Expansion machines play vital role on the system design and performance. In fact, the system performance is substantially affected by changing turbine operating conditions or geometric parameters as proven in the current study. The current study presents an automated radial turbine model. The model encompasses design point sub-model, off-design sub-model and ORC-PTC sub-model. The radial turbine sub-model is validated against experimental data. Solar irradiance in Hail city, Saudi Arabia, is utilized to investigate the feasibility of the proposed model. The results showed that turbine operating conditions and design parameters affect the solar ORC performance considerably. For instance, increasing the evaporation pressure by 100 kPa resulted in 17.5% smaller turbine. When the turbine pressure ratio increased from 1.5 to 4.5, the PTC efficiency decreased by 1.7%, while the solar ORC efficiency increased by 200%. On 6th of July 2022, in Hail city, the proposed model presented a maximum net power output and thermal efficiency of 2.15 kW and 8.78%, respectively, at noon time.

Combination of solar with organic Rankine cycle as a potential solution for clean energy production

The increasing requirement for energy, severe environmental problems, and the paucity of traditional sources of energy were among the most pressing global challenges which needed addressing immediately. Hence, the utilization of solar energy was such a vital tool for confronting critical issues including global warming, the depletion of fossil fuels as well as rising energy consumption owing to new lifestyle tendencies. More importantly, the organic Rankine cycle (ORC) was demonstrated to be a dependable technology capable of efficiently transforming low-to-medium-level heat sources into usable uses. Because of the great compatibility between the solar thermal-based collector technologies' working temperatures and the cycle’s required temperatures, using solar irradiation to drive an ORC was a viable technique based on renewable energy. The key significance of this review lies in summarizing the utilization of solar-driven ORC and its potential for the applications like water desalination, water pumping, and power generation. The key features like working fluid consideration and component selection are highlighted. Also, the challenges in the sector and the scope for further studies are discussed in detail. The final remarks show that solar ORC can be considered a promising avenue for the development of sustainable energy systems in a broader view.