Expander Inlet Temperature Research Articles

Comparison Study of Cascaded Organic Rankine Cycles with Single and Dual Working Fluids for Waste Heat Recovery

This study compares thermodynamics, economics, and environmental performance of cascaded ORCs operated under a single and dual fluids. In the single fluid cascaded ORC, toluene, benzene, acetone and cyclopentane are run in high and low temperature cycles, whereas in dual fluid cascaded ORC, toluene, benzene, acetone and cyclopentane are run in high temperature cycle and R601a in the low temperature cycle. The analysis compares variations in expander inlet temperature and condensation temperature. Thermodynamic performance involved net power output (Pnet) and thermal efficiency (ηth), while economic indicators included net present value (NPV) and levelized cost of electricity (LCOE). In environmental performance, the annual reduction in carbon dioxide emission (CO2-eq) is assessed. The findings revealed that dual fluid cascaded ORC generated the highest Pnet of 1245.11 kW while single fluid cascaded ORC reached 1170.27 kW. The dual fluid cascaded ORC showed the significant increase in Pnet (%DPnet) for about 43% at the lowest expander inlet temperature (500 K). In terms of ηth, dual fluid cascaded ORC attained 37.23 % while single fluid cascaded ORC reached 33.25%. It is further found that acetone+R601a performed well in dual fluid cascaded ORC, resulting in the highest Pnet and allowing system’s NPV to turn positive sooner than other fluids. Furthermore, cyclopentane+R601a had the lowest LCOE of 0.0158 US$/kWh, which is 1.1% lower compared to the single fluid cascaded ORC and competitive in the Thai electricity market. In environmental saving, dual fluid cascaded ORC reduced about 144.96 tCO2-eq/year, and outperformed single fluid cascaded ORC by roughly 6.39%.

The benefits of a recuperative layout of an ORC-based unit fed by a solar-assisted reservoir operating as a micro-cogeneration plant

Organic Rankine Cycle -based microcogeneration systems that exploit solar sources to generate electricity and domestic hot water simultaneously are promising solutions for reducing CO2 emissions in the residential energy-intensive sector. Such systems can be assisted by thermal energy storage reservoirs in which water is heated by solar energy and cooled by the direct use of thermal energy for domestic hot water production and acting as heat source of the power plant. An interesting plant layout optimisation involves the adoption of a recuperative heat exchanger to preheat the working fluid before it enters the heat recovery vapour generator, which is fed with the same working fluid leaving the expander. Despite the positive effect of recuperative heat exchanger adoption on the efficiency of the entire plant, the impact on electrical energy production at this microscale is not straightforward to assess as the heat source is represented by the water inside the reservoir and it is not a continuous high- or medium-temperature stream. The lack of experimental analyses in the literature on these applications makes this a debatable question.Thus, to fill this gap and quantitatively assess the benefits introduced by the adoption of a recuperative stage, a wide experimental comparison between recuperative and not-recuperative Organic Rankine Cycle-based power unit layout was performed. To support the experimental analysis, a comprehensive theoretical model of the Organic Rankine Cycle-based plant was developed and validated against experimental data.The experimental campaign demonstrated that the recuperative Organic Rankine Cycle-based unit required a lower working fluid flow rate for a given expander inlet temperature and pressure ratio. Consequently, a higher electrical power can be produced, requiring lower thermal power from a heat source. The reduction in the thermal power absorbed from the heat source, produced by a higher temperature incoming working fluid entering the Heat Recovery Vapor Generator, had a positive effect, allowing a longer-in-time working condition with a higher conversion efficiency intrinsically produced by the recuperative heat exchanger. Considering the annual electricity consumption of 2700 kWh of a family living in a city in central Italy, the contribution given by the recuperative Organic Rankine Cycle plant operating with a reservoir fed by 15 m2 of flat solar panels was 330 kWh, whereas without the recuperative stage, the production was 240 kWh. The cost of electricity saved justified the adoption of a recuperative heat exchanger.

Thermo-Economic Performance of Organic Rankine Cycle-Based Waste Heat Recovery for Power Generation at a Wide Range of Operating Conditions

This study assesses the performance of organic Rankine cycle-based waste heat recovery systems under different working fluids and operating conditions. The basic ORC (BORC) and ORC with recuperator (RORC) are investigated for power generation and economy using toluene and benzene. Thermodynamic and economic indicators are studied at various expander inlet temperatures, expander inlet pressure, evaporation temperature, and condensation temperature. RORC achieves higher ηth by reducing heat source in the evaporator whereas BORC recovers more waste heat and improves Pnet. With toluene, BORC improves Pnet when increasing the expander inlet temperature and pressure. The lowest LCOE of 0.0532 US$/kWh is from BORC operated with toluene at a Pnet of 349 kW and decreases with an increase in expander inlet temperature. The addition of a recuperator adds to the costs of initial investment and LCOE and slightly improves the performance of the ORCs for waste heat recovery.

Study on the thermodynamic performance of a coupled compressed air energy storage system in a coal-fired power plant

Coupled energy storage can improve flexibility levels, increase renewable energy consumption, and alleviate the energy crisis of thermal power systems. In this article, 11 coupling schemes for the CAES and CFPP systems are proposed, and a mathematical model for the coupled system is established. An optimal coupling scheme is determined through simulation analysis and comparison by using the heat rate and energy utilization coefficient as evaluation indicators. In the energy release stage, the energy utilization coefficient of the coupled system increases by 2.842 %, and the heat rate in the energy storage stage decreases by 50.546 kJ · (kWh) −1, with a return water temperature of 120 °C. The effects of key parameters, such as compressor inlet air temperature, storage chamber pressure, and expander inlet temperature, on the thermodynamic performance of the coupled system are explored, and the NSGA-II multiobjective optimization algorithm and TOPSIS optimization algorithm are used to optimize the key parameters and obtain the optimal performance-related parameters of the system: a compressor inlet air temperature of 35 °C, expander inlet air temperature of 105.4 °C, and storage pressure of 9.105 MPa. At this time, the RTE of the system is 55.573 %, and the ηhe value is 1.59. The results indicate that the coupled CAES energy storage stage can assist the CFPP in absorbing renewable energy, and the energy release stage can alleviate the pressure of its high electricity load demand, effectively improving its flexibility.

Multidisiplinary design optimization of a power generation system based on waste energy recovery from an internal combustion engine using organic Rankine cycle and thermoelectric generator

The research paper mainly deals with waste heat recovery from internal combustion engines (ICE) using the organic Rankine cycle (ORC) and Thermoelectric generator (TEG). Simultaneously recovering the wasted heat of both exhaust gases and coolant, a novel configuration named two-stage is proposed. Then a comprehensive thermo-economic analysis and optimization are conducted. Produced power and total cost rate are selected as the objective function of the optimization. Also, the first and second stage pressures of the ORC system are considered as decision variables. Finally, a sensitivity analysis is performed to study the effect of expander inlet temperature, pumps isentropic efficiency, and expander isentropic efficiency on the objective function.

Thermodynamic analysis of photothermal-assisted liquid compressed CO2 energy storage system hybrid with closed-cycle drying

Liquid compressed carbon dioxide (CO2) energy storage (LCES) is promising by mechanically storing the electricity into the high-pressure liquid CO2. However, the thermal efficiency of the expander, i.e., energy release process, is strictly limited by the outlet temperature of the compression heat storage. To this end, a photothermal-assisted LCES system is proposed to increase the inlet temperature of expander. A heat integration scheme of the new system is proposed by deploying the closed-cycle drying chamber for the waste heat recovery, whose performance is compared with the conventional organic Rankine cycle (ORC) method. By developing the thermodynamic models of the systems, numerical results indicate that the photothermal assistance significantly enhances the thermal performance of LCES system, with the exergy efficiency increased by 16.00 % to 62.23 % and the energy storage density increasing from 8.06 kWh/m3 to 18.59 kWh/m3, respectively. The comparative results of different waste heat recovery schemes show that the closed-cycle drying is of 2.77 times waste heat recovery benefit of the ORC method, with a dehumidification capacity being 63.45 kg/h. Moreover, the closed-cycle drying subsystem with a recuperator is designed to recover the sensible heat of the moist air at the outlet of the drying chamber, which further improves the dehumidification capacity by 52.04 % at a drying chamber outlet temperature of 319.15 K.

Thermodynamics, flexibility and techno-economics assessment of a novel integration of coal-fired combined heating and power generation unit and compressed air energy storage

The new power system with increasingly high renewable energy proportion necessitates the combined heating and power (CHP) generation units to provide more flexibility. With full consideration of operation characteristics, this paper firstly proposes an advanced coal-fired CHP-CAES system consisting of a 350 MW coal-fired CHP unit and a 30 MW CAES system, which realizes more efficient energy utilization and enhances the system adjusting flexibility through thermal cycles integration and energy comprehensive utilization. The thermodynamic models and multi-dimensional performance analysis models are separately established. Based on that, the comparative study is conducted for two CHP-CAES configurations and the stand-alone CHP unit. With 80% heating load, the minimum power ratio is lowered by 11.69% rated power and the maximum power output is increased by 6.35% rated power, and 27.26 tons of coal can be saved for a single cycle compared with the stand-alone CHP unit. The results also demonstrate that the system still has superiority when the load ratio changes. Techno-economic evaluations for a typical application scene show that the dynamic payback period of the proposed system is shortened by 10.41 years compared with the reference separate CHP-CAES system. These results show that the proposed system presents better performance in energy utilization, enhancing flexibility, realizing clean and low-carbon heating as well as techno-economics. In addition, parametric analysis is implemented to find the influence of CAES parameters on the system. It is found that increasing the expander inlet temperature and air storage pressure can further enhance the system round-trip performance. Yet, the investment cost increases greatly for higher storage pressure and the payback period will be lengthened. Furthermore, the system advantages are strengthened with a CAES system of greater capacity. Nevertheless, we find that the deep coupling in the thermodynamic cycle of the two systems results in an upper capacity for the integrated CAES system, and it is nearly 35 MW for the studied system. These regularities and conclusions can provide theoretical guides and directions for the customized CAES system design with the purpose to integrate with a coal-fired CHP unit.

Experimental investigation and machine learning optimization of a small-scale organic Rankine cycle

The system behaviors of a small-scale organic Rankine cycle (ORC) system using a scroll expander under various operating conditions, as well as the machine learning optimization based on back propagation artificial neural network (BPANN), are investigated in this study. The effects of pump outlet pressure, expander inlet temperature and mass flow rate on net power output and thermal efficiency are examined experimentally. A BP-ORC neural network model is constructed, and the prediction accuracy is analyzed by the errors between the experiment and predicted data. The effects of eight operating parameters on system performance are discussed. The bi-objective optimization for maximum net output power and maximum thermal efficiency is addressed. Results indicate that as the mass flow rate increases, the net power output presents an increase trend, whereas the thermal efficiency yields a smooth tendency. The absolute error in the net power output from the BP-ORC model is between −0.05 kW and 0.05 kW, while that in the thermal efficiency is between −8 × 10-5 and 8 × 10-5. The Pareto-optimal solution of thermal efficiency is 9.32 % and the net output power is 2.42 kW.

Thermodynamic and Heat Transfer Performance of the Organic Triangle Cycle

Compared to the organic Rankine cycle (ORC), the organic triangle cycle (TC) is simpler in structure and is not limited by pinch point temperature differences. TC has been studied to some extent by previous researchers, such as the selection of working fluid, application, and the design of the expander. However, system optimization and parameter analysis of TC are still rare. The thermodynamic performance of TC internal circulation and TC heat recovery systems are investigated by theoretical analysis and numerical simulation, respectively. The results indicate that the expander inlet temperature T3 and heater inlet temperature T2 are key elements impacting the thermodynamic performance of the TC internal circulation. For the TC heat recovery system, an optimal value of the average heat-capacity flow rate of working fluid Cwf is discovered to output the maximum net power output Wnet. Moreover, the total heat transfer coefficients for the heater (kA)h and condenser (kA)c are discussed in relation to Cwf variations. The findings will provide critical guidance for system investment and optimization.

Study on the coupled characteristics of high-speed centrifugal compressor and turboexpander of a reverse Brayton air refrigerator

Reverse Brayton air refrigerators are environmentally friendly and have broad application prospects, which can work under various conditions. In this paper, the characteristics of a open-loop air cycle for room temperature applications were investigated. The compressor and turboexpander in the cycle were modeled by numerical simulation. Based on coupled characteristics of the compressor and expander, a system model was established. The effects of the first stage compression ratio and the expander inlet temperature on the refrigerator performance were studied by experiments. The accuracy of the system model is verified by comparing with the experiments, and the maximum deviations of expander rotating speed and supplied mass flow are 3.1% and 4.83%, respectively. With the increase of the first-stage compression ratio and the decrease of expander inlet temperature, the mass flow rate of supplied air and cooling capacity of the cycle increase. The expander efficiency can be maintained near the optimal value. At the expander inlet temperature of 313.2 K, COP drops by 31.7 % when the cooling capacity is reduced from 3.34 kW to 0.74 kW.

Operation characteristics and performance prediction of a 3 kW organic Rankine cycle (ORC) with automatic control system based on machine learning methodology

Automatic control system enables the laboratory organic Rankine cycle (ORC) to adapt to variable operating conditions of industrial application. In this study, the operation characteristics of a 3 kW ORC with automatic control system applied to a chemical plant, as well as the performance prediction and optimization using machine learning methodology, are addressed. The dynamic behaviors for startup, operating and stop stages are discussed. The BP-ORC neural network model is established based on 3400 sets of experimental data, while the prediction accuracy is analyzed based on the errors of the training and test samples. The effects of six operation parameters on system performance are examined, while the bi-objective optimization for maximum thermal efficiency and maximum net output work is investigated. Results indicate that the component response times for startup stage and stop stage are 90s and 300s, respectively. Increasing the mass flow rate, decreasing the expander outlet temperature and increasing the expander inlet temperature ensure a higher net output work, while increasing the expander inlet temperature, decreasing the expander outlet temperature and increasing pump outlet pressure enable a higher thermal efficiency. The optimum net output work and thermal efficiency from Pareto-optimal solution are 2.87 kW and 8.855%, respectively.

Analysis of solar energy driven organic Rankine cycle-vapor compression refrigeration system

Integration of an organic Rankine cycle-vapor compression refrigeration system with an N series fully covered photovoltaic thermal compound parabolic collector is done in this study. The system is designed to produce electrical power and cooling effect simultaneously. The exergy efficiency (ηex), coefficient of performance (COPs), and the net mitigation of carbon dioxide per solar collector unit area (mCO2) have been selected as the performance assessment parameters based on energy, exergy, and environmental criteria. Moreover, the effect of expander inlet temperature (T7), packing factor (λcl), and the number of collectors (N) on the energy, exergy, and environmental performance of the system have been studied. Results show that the system's energy (COPs) and exergy (ηex) performance is maximum at an expander inlet temperature of 423 K and packing factor of 0.25. The corresponding maximum values of COPs and ηex are 1.81 and 5.8 %, respectively. However, the system has maximum environmental performance (mCO2 = 1999 g m−2) at the expander inlet temperature of 373 K and packing factor of 0.89. ηex and mCO2 are increased to 17.4 % and 8546 g m−2, respectively, as the number of collectors increased from 1 to 5.

Thermal performance analysis of a solar-driven supercritical CO2 split-flow recompression Brayton cycle

ABSTRACT Solar is a clean and renewable energy, and is considered as the desired heat source of supercritical CO2 Brayton cycle. The heliostat field and cavity receiver of DAHAN tower solar thermal power station in China are used for analyzing the geometric relations between the sun, heliostat field and the receiver. The ray-tracing method is applied to establish a model to calculate the heat flux distribution of heating surface in the receiver. According to the absorbed heat, the supercritical CO2 split-flow recompression Brayton cycle model can be built via the Aspen HYSYS software. The uneven distribution on the heating surfaces represents a higher heat flux at the center of the spot and a lower heat flux away from the spot. The maximum heat flux is 224 kW·m−2 at 9:00 am, 349 kW·m−2 at 12:00 noon, and 215 kW·m−2 at 3:00 pm. Based on this distribution, the thermal efficiency of DAHAN tower solar thermal power station can be obtained by modeling. Compared with the steam Rankine cycle, the thermal efficiency of supercritical CO2 Brayton split-flow recompression cycle has a 50% increment. Subsequently, the effects of the split-flow ratio, the inlet temperature and pressures of turbo expander and main compressor, and the heat absorption on the thermal performance of system are obtained. Finally, the optimal parameters are obtained as follows: the split-flow ratio is 0.605, and the inlet pressures of turbo expander and main compressor are 24 and 7.9 MPa, respectively. These interesting findings are particularly significant for the application of supercritical CO2 split-flow recompression Brayton cycle system and the operating parameters’ selection in solar thermal power generation stations.

Characteristic analysis of compressed air energy storage system based on intermediate cooling

With the shortage of traditional fossil energy and the aggravation of global warming, the demand for transformation from traditional fossil energy to renewable energy becomes more and more urgent. Compressed air energy storage technology is a guaranteed technology to overcome the time limit of renewable energy and achieve sustainable, efficient and large-scale application of renewable resources. In order to solve the traditional compressed air energy storage technology energy output variety is single, there is low grade energy waste defects. This paper presents a compressed air energy storage system based on intermediate cooling. Through the intercooler, the system adjusts the inlet temperature of the expander, improves the output cooling quality, and realizes the coupling operation of refrigeration and energy storage. This paper establishes a thermodynamic model of the system, analyzes the effects of ambient air temperature and inlet temperature of expander on system performance, and compares the energy efficiency ratio of the system with that of compressed air refrigeration system. The simulation results show that the system can adjust the inlet temperature of expander to increase the net power consumption and achieve high quality cooling output.

Thermal-mechanical coefficient analysis of adiabatic compressor and expander in compressed air energy storage systems

Compressed air energy storage (CAES) technology can play an important role in large-scale utilization of renewable energy, the peak shaving and valley filling of power system, and distributed energy system development. Multi-stage compression and expansion units are key components in CAES systems, while the two key processes exist insufficient study, such as a lack of considering the coordination of temperature and pressure, ignoring coupling relationship between compressor and expander when typically being analyzed independently. To cope with the above critical issues, the new concept of thermal-mechanical coefficient is put forward based on the coupling relationship between temperature and pressure in adiabatic compression and expansion processes, and a C–P diagram (C is thermal-mechanical coefficient, and P is a function of pressure) is established to illustrate the thermodynamic processes concentrating on their work transfer. Besides, the expression of change rate of exergy to enthalpy for adiabatic compression and expansion processes is revealed. By depicting the C–P diagram of single-stage CAES system, it highlights that the thermal-mechanical coefficient of expander is higher compared with that of compressor, but with shorter change in the x-coordinate representing P that results in smaller work output for expander. In addition, it is found that the change of thermal-mechanical coefficient is generally accompanied with thermal-work conversion or heating/cooling effect. When drawing the C–P diagram of a multi-stage CAES system, the influence of heat exchanger's heat/pressure loss and the reduction of expander stage number on system's work transfer process is clearly shown. Significantly, results show that increasing the inlet temperature of expander is beneficial to enhance thermal-mechanical coefficient, which enables the thermal-work conversion ratio to be improved especially at higher inlet pressure and lower outlet pressure.

Experimental investigation on steady and dynamic performance of organic Rankine cycle with R245fa/R141b under different cooling and expander speed conditions

A kW-scaled organic Rankine cycle (ORC) experimental apparatus with a modified scroll compressor as the expander was established to investigate its operation characteristics. The test rig uses steam with a temperature of about 110°Cfrom a 30 kW electric steam generator as the heat source. In this study, the steady-state performance and dynamic response of R245fa/R141b (mass ratio 0.5/0.5) and R245fa under variable cooling water flow rate and expander rotational speed are experimentally studied. In the steady-state experiments, system thermal efficiency decreases with the increase of expander rotational speed. The mechanical efficiency of scroll expander is in the range of 91%–99%. Additionally, the maximum shaft power and isentropic efficiency of the expander and thermal efficiency of ORC system with R245fa/R141b are 831 W, 58%, and 5.2%, respectively. Compared with R245fa, the maximum shaft power and thermal efficiency of R245fa/R141b are increased by 9.9% and 13.0%, respectively. In the dynamic experiment, the disturbance of rotational speed and cooling water flow rate has little influence on the inlet temperature of expander. Under the disturbance of the rotational speed, the response time of shaft power, torque and speed of expander is in the range of 1–5s. The dynamic response of the ORC system is mainly controlled by the condenser and pump. Under the disturbance of coolant flow rate, the response time of pump inlet temperature and outlet temperature is about 350s and 600s, respectively. The ORC system using R245fa and R245/R141b have the same response speed.

Modeling of an Organic Rankine Cycle Waste Heat Recovery system for automotive engine applications

The remarkable investments made by manufacturers over the last few decades have contributed to improving the performance of internal combustion engines in every aspect: lower polluting emissions, greater specific power and thermal efficiency. Despite this, on an average, about 40% of the thermal power theoretically available from the combustion of the fuel is still stored in the exhaust gases and therefore dispersed in the environment. In this work the modeling and validation of a waste heat recovery (WHR) plant will be described, combining the engine with a low temperature Organic Rankine Cycle (ORC) system, in order to investigate the feasibility of this system on board of a vehicle, analyzing the quantity of thermal power recovered and made available in the form of electrical power. The ORC plant is modeled using a 0D/1D thermo-fluid dynamic approach. Starting from experimental tests, a map-based model for the piston pump and the scroll expander has been developed. The model has been validated through the use of a vector optimization technique, exploiting a genetic algorithm (MOGA). Subsequently, this system has been coupled to a spark ignition engine for automotive applications, adapting its speed range to comply with the ORC experimental tests. To have an accurate control over the expander inlet temperature, a bypass circuit and two throttles actuated by a PI controller have been implemented. The simulations were performed by considering 18 engine points at maximum load and different rpm. An average thermal efficiency increase of the system of 2.6% was obtained by introducing the recovery plant, and wide improvement chance can be foreseen in the case of ORC full-power use.

Simulation of the HiPowAR power generation system for steam-nitrogen expansion after ammonia oxidation in a high-pressure oxygen membrane reactor

The EU project HiPowAR studies a novel power generation system based on ammonia flameless oxidation with pure oxygen in a high-pressure membrane reactor and expansion of the resulting high-temperature H2O-N2stream. The system combines the advantages of high temperature at expander inlet, typical of gas turbines, and small compression demand, typical of steam cycles. Water is injected into the reactor to control the very high adiabatic temperature, at the limited energy expenditure of liquid pumping. This work assesses the performance potential of the HiPowAR system under different design conditions, through simulations with a model developed in Aspen Plus®. The system shows a high efficiency (up to 55%) when operating at high temperature (e.g., 1350°C at expander inlet); hence, O2 membranes capable of working at very high temperature are required. The cycle features an optimal sub-atmospheric expansion pressure (in the range 0.1-0.2 bar), which requires the re-pressurization of the off-gas (steam-saturated nitrogen). The system also produces liquid water as a net output. A reduction of the expander inlet temperature to values acceptable by typical steam cycles (600°C) significantly limits the efficiency, despite allowing to demonstrate the process using conventional steam expanders.

Thermodynamic Evaluation and Sensitivity Analysis of a Novel Compressed Air Energy Storage System Incorporated with a Coal-Fired Power Plant.

A novel compressed air energy storage (CAES) system has been developed, which is innovatively integrated with a coal-fired power plant based on its feedwater heating system. In the hybrid design, the compression heat of the CAES system is transferred to the feedwater of the coal power plant, and the compressed air before the expanders is heated by the feedwater taken from the coal power plant. Furthermore, the exhaust air of the expanders is employed to warm partial feedwater of the coal power plant. Via the suggested integration, the thermal energy storage equipment for a regular CAES system can be eliminated and the performance of the CAES system can be improved. Based on a 350 MW supercritical coal power plant, the proposed concept was thermodynamically evaluated, and the results indicate that the round-trip efficiency and exergy efficiency of the new CAES system can reach 64.08% and 70.01%, respectively. Besides, a sensitivity analysis was conducted to examine the effects of ambient temperature, air storage pressure, expander inlet temperature, and coal power load on the performance of the CAES system. The above work proves that the novel design is efficient under various conditions, providing important insights into the development of CAES technology.

Performance analysis and sensitivity of system parameters on the performance of trilateral-cycle power generator systems

ABSTRACT Though the trilateral cycle (TLC) is a promising heat recovery-to-power cycle, its application has not been widely accepted or commercialised due to some thermodynamic feasibility concerns. This study examined the performance analysis and sensitivity of the system parameters on the thermodynamic performance of the TLC power generator systems for waste heat recovery-to-power generation. Thermodynamic models of the simple, recuperative, reheat and regenerative TLCs were established. Performance analysis and sensitivity of the system parameters on the cycles’ performance were conducted at the expander inlet temperature of 453 to 473 K, expander pressure of 2 to 3 MPa and expander isentropic efficiency of 50% to 100%. The expander inlet temperatures, pressures, and its isentropic efficiencies have significant effects on the thermodynamic efficiencies and net work output of the cycles. At 473 K cycle high temperature, the thermal efficiencies of the cycles increase from 20.13% to 21.97%, 23.29% to 23.91%, 20.62% to 22.07% and 20.66% to 22.9% for the simple, recuperative, reheat and regenerative TLCs, respectively. Their corresponding net power outputs varied from 131.6 to 134.1 kW, 145.9 to 152.2 kW, 113.8 to 124.1 kW and 124.9 to 130.5 kW, respectively. The cycles’ thermodynamic performance increased with an increase in expander inlet temperature, expander pressure and expander isentropic efficiencies.