Efficiency Of Organic Rankine Cycle Research Articles

Techno-Economic Analysis of Waste Heat Recovery in Automotive Manufacturing Plants

This study proposes an innovative system for recovering waste heat from exhaust air after a regenerative thermal oxidiser process, integrating a Carnot battery and photovoltaic (PV) modules. The Carnot battery incorporates an organic Rankine cycle (ORC) with a recuperator, thermal energy storage (TES), and heat pump. Waste heat is initially captured in TES, with additional energy extracted by a heat pump to increase the temperature of a secondary fluid, effectively charging TES from both direct and indirect sources. The stored heat enables electricity generation via ORC. The result of this study shows a heat pump COP between 2.55 and 2.87, the efficiency of ORC ranging from 0.125 to 0.155, and the power-to-power of the Carnot battery between 0.36 and 0.40. Moreover, PV generates 1.35 GWh annually, primarily powering the heat pump and ORC system pump. The proposed system shows a total annual net generation of 4.30 GWh. Economic evaluation across four configurations demonstrates favourable outcomes, with a return on investment between 25% and 160%. The economic evaluation examined configurations with and without the PV system and recuperation process in the ORC. Results indicate that incorporating the PV system and recuperator significantly increases power output, offering a highly viable and sustainable energy solution.

Low-grade heat utilization for combined cycle power plants using organic rankine cycle

This paper presents a comprehensive thermodynamic analysis of trinary power plants, focusing on the efficiency of Organic Rankine Cycle (ORC) configurations and regenerative heating methods. Despite advancements in nuclear and renewable energy, fossil fuels still dominate electricity generation, necessitating improved efficiency in existing power plants. The study reveals that low-pressure mixing-type heaters provide higher efficiency compared to surface heaters, with net efficiencies of 0.099%, 0.227%, and 0.425% at deaerator pressures of 0.12, 0.3, and 0.7 MPa, respectively. The analysis highlights the impact of feedwater temperature on the thermal efficiency of steam turbine units (STUs), noting that while optimal feedwater temperatures enhance efficiency, they can reduce STU capacity. The study identifies configurations for regenerative heating that optimize exhaust gas temperatures, facilitating additional electricity production through a low-boiling working fluid in the ORC. The findings indicate that R245fa refrigerant is optimal for ORC without recuperative heater, achieving maximum net power at a feedwater temperature of 115°C. For ORC with a recuperative heater, R236ea is preferred for temperatures between 115°C and 154.5°C, while R245fa is optimal for higher temperatures. The results also demonstrate that trinary power plants with recuperators achieve greater efficiency and net capacity compared to double-circuit systems, with notable improvements in thermal efficiency attributed to effective regeneration schemes. This research underscores the potential for optimizing existing domestic power units to enhance their efficiency and performance without significant financial or technical burden, thereby contributing to more sustainable energy generation.

Optimal dual-pressure evaporation organic Rankine cycle for recovering waste heat from compressed air energy storage (CAES)

Compressed Air Energy Storage (CAES) is an effective solution to the problems of the intermittency and volatility of renewable energy. However, the process of compressing air consumes energy and converts it into low-temperature waste heat, limiting the improvement of round-trip efficiency. This paper introduces the dual-pressure evaporation organic Rankine cycle (ORC) to recover the waste heat from the CAES system compression process, which enhances the round-trip efficiency. Optimal working fluids and design schemes of parallel and series dual-pressure evaporation ORCs are analyzed. The thermodynamic performance of two cycle types is compared. The exergy loss distribution characteristics of the dual-pressure evaporation ORC are explored, and the impact on the round-trip efficiency of the CAES system is evaluated. Results show that the parallel dual-pressure evaporation ORC has better performance with an optimum working fluid of R1234yf and a maximum waste heat conversion efficiency of 9.3 %. The round-trip efficiency of the CAES system will be relatively increased by 5.2 % by introducing the parallel dual-pressure evaporation ORC. The maximum exergy efficiency of the parallel dual-pressure evaporation ORC is 52.8 %, and the condenser and low-pressure stage expander have larger exergy losses, accounting for 33.8 % and 22.0 % of the total losses, respectively.

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.

Thermoeconomic analysis of a novel configuration of a biomass‐powered organic Rankine cycle for residential application with consideration the effect of battery energy storage

AbstractIn this article, the energy, exergy, and economic analysis of an organic Rankine cycle (ORC) system powered by biogas to provide electricity, heating, and cooling loads for a residential building in Munich city is investigated. Two methods have been proposed to meet the heating and cooling needs of the residential building. In the first method, heating and cooling needs are provided by a heat pump and mechanical refrigeration (System I), and in the second method, these needs are provided by a radiator and absorption refrigeration cycle (System II). In both modes of this system, the effects of battery energy storage (BES) have been analyzed for peak shaving. The working method of this research is that the residential building's electricity, heating, and cooling needs are calculated by Homer and Carrier software, respectively. Engineering equation solver software models the main local power generation system. A new method has been proposed to select the required number of units to meet the needs of the building with and without BES. The results showed that for System I with and without BES, 3 and 1 ORC units with a nominal power of 2 kW can meet all the needs of the building, respectively. In contrast, for System II, the number of 1 unit with 2 kW and 1 unit with 1 kW is needed to meet the energy needs of a residential building with and without BES. It can be concluded that heating and cooling the building with a radiator and absorption chiller cycle is more cost‐effective. The energy and exergy efficiency of ORC is reported as 11.3% and 65.7%, respectively, and the highest exergy destruction rate is related to the heater and boiler. From the economic point of view, the payback period of System II compared with System I is reduced from 18.4 to 5.66 years without using BES. With the use of BES, the payback period is reduced to 5.3 and 5.66 years, respectively. The lowest and highest electricity prices belong to System I with and without BES, which are 3.11 and 0.36 US$/kWh, respectively.

Heat integration, simultaneous structure and parameter optimisation, and techno-economic evaluation of waste heat recovery systems for petrochemical industry

Energy conservation in the petrochemical sector holds the key to its financial viability. The pervasive application of Heat Exchanger Networks (HEN) exemplifies the industry's efforts in heat recovery. Yet, despite its widespread adoption, an alarming quantum of low-grade heat remains squandered, underscoring the potential for augmenting energy savings through more effective utilization of this heat. Recognizing the pivotal role of the synergistic interaction between the process and the heat recovery system in maximizing energy retrieval, an innovative approach is proposed. This methodology initially entailed the development of a process model and an enhanced heat recovery system, the latter embodying the integration of an organic Rankine cycle (ORC) with HEN. Subsequently, a strategic diagnostic was proposed to incorporate these sub-systems into a cohesive, optimisation framework. Following this, an array of energy, exergy, and economic analyses were conducted to appraise the system's performance. The findings suggest a considerable improvement in heat recovery and an amplification in ORC efficiency from a mere 7.64%–11.38%. The enhanced heat recovery further translated into a reduced need for cold utility, thereby minimizing cooler deployment. Given the substantial exergy destruction associated with coolers, their lesser usage bolstered the system's exergy efficiency. Moreover, the optimised ORC manifested in heightened net power generation, consequently elevating electricity revenues. Despite a nominal surge in equipment costs, the aggregate profit witnessed a substantial hike from 165.19 M$/year to 178.79 M$/year. The proposed system substanitally improved thermodynamic and economic performance. This study offers valuable guidance for the design and operation of petrochemical industries, serving as a roadmap to energy conservation and enhanced profitability.

Energetic/exergetic study of Kalina and refrigeration bottoming cycles on different solar‐driven organic Rankine cycles

AbstractCombination of different power cycle scenarios is of prime importance in achieving maximum energy utilization from solar‐driven multigeneration systems. To fulfill such objective, the present article proposes a novel energy distribution system, leveraging a combination of direct‐fed organic Rankine cycle (ORC) and a bottom‐cycled arrangement of Kalina cycle system (KCS) and double‐effect absorption refrigeration cycle (DEARC) within a parabolic trough solar collector powered trigeneration system. The study explores three different ORC configurations: simple ORC; ORC equipped with internal heat exchanger (ORC‐IHE) and regenerative ORC (RORC). It is shown that although higher efficiencies are achievable from a larger portion of PTSC energy absorbed by the ORC, the ORC energy absorption is limited by ORC evaporator temperature differences, and there is unused energy that can be recovered by the KCS, based on the proposed energy system. The results indicate that the addition of bottoming KCS leads to a considerable increase in the exergy efficiency of ORC, ORC‐IHE and RORC‐based systems by 11.7%, 30.7% and 32.6%, respectively. The impact of different ORC configurations, key ORC parameters and various organic working fluids on the energetic/exergetic efficiencies is also examined to find the optimal configuration. In terms of overall energetic/exergetic efficiencies, the highest performance belongs to ORC (78.4%/30.4%) while the lowest energetic and exergetic efficiencies belong to ORC‐IHE and RORC, respectively (56.3% and 25.65%). On the basis of a comparative study with the available literature, these values are higher than what is already reported for similar solar‐driven multigeneration systems. Appropriate thermal match and lower exergy destruction in the KCS, and bottoming cycle arrangement of the DEARC are the main reasons for such enhanced performance. This research not only contributes valuable insights into efficient solar‐driven systems but also sets a new benchmark for performance metrics in the existing literature.

Feasibility and performance analysis of utilizing spent mushroom substrate as biomass fuel

A novel biomass system has been developed that utilizes spent mushroom substrates (SMS) and combines a pre-drying and drying system. The novel biomass system consists of a boiler and an Organic Rankine Cycle (ORC), which employs Isohexane as the working fluid to enable operation at high temperatures. The high moisture content of the SMS is dried by pre-drying from condensation waste heat of ORC and drying from the flue gas of the boiler to improve the calorific value of SMS. In the present study, the moisture content of the SMS and evaporation temperature of the ORC ranged from 50% to 65% and from 130℃ to 180℃. The results show although the thermal efficiency of ORC increased with an increase in evaporation temperature, the maximal output power is 412.21 kW at an evaporation temperature of 150 ℃. Additionally, when the moisture content of the SMS is 50 %, the thermal efficiency of the entire system approaches the maximal value (58.6%).

Thermal efficiency investigation for organic Rankine cycle and trilateral flash cycle using hydrofluoroether working fluids

The thermal efficiency of the organic Rankine cycle (ORC) is higher than the trilateral flash cycle (TFC) using normal dry working fluids. On the contrary, the thermal efficiency of TFC outperforms the thermal efficiency of ORC by using super dry working fluids at specific conditions. This study aims to investigate thermal efficiency for TFC and ORC cycles using HFE7100 and HFE7500, classified as super dry working fluids. The effect of two techniques was studied on the thermal efficiency of ORC and TFC: the recuperator cycle (RORC and RTFC) with various ratios of effectiveness and the partial evaporator organic Rankine cycle (PE-ORC), with various ratios of vapor quality. The results indicated that the recuperative heat exchanger helps convert the super dry behavior to be like normal dry. Therefore, using HFE7100 required 0.2 effectiveness of recuperative heat exchanger, while for HFE7500, 0.4 effectiveness is needed. A partial evaporator cannot help convert the super dry's behavior to the normal dry fluid completely, while it has the crucial role of moving the intersection point towards critical temperatures (Tcr), which increases the range of heat source temperatures that assist super dry fluids to behave as normal dry fluids. However, PE-ORC can be a good competitor to TFC at vapor quality (x = 0.1, and x = 0.2) and (x = 0.1), and it has higher thermal efficiency than ORC at vapor quality (x = 0.9) and (x = 0.8 and x = 0.9) for HFE7100, and HFE7500 respectively.

Numerical simulation and low speed experiment of a low partially admitted rate axial turbine for small scale organic Rankine cycle

High rotating speed is a prominent feature of turbine used for small-scale organic Rankine cycle (ORC) system, which can bring the problems of safety, reliability, sealing, vibration, economics, etc. Partial admission method has potential to reduce the rotating speed of small turbine. In this study, an axial turbine with low partially admitted rate of 0.033 was tested in ORC loop using R1233zde as working fluid, and numerically researched using Ansys CFX software with k-omega turbulence model. Results showed that the specific powers of turbine resulting from CFD should be corrected with losses to match well with the experimental results. Losses could reduce the optimal rotating speed of turbine. The optimal rotating speed, mass flow rate, power and efficiency of turbine under rated condition were 8000 RPM, 115.8 g/s, 611.8 W and 35.8 %, respectively. The corresponding power and thermal efficiency of ORC were 551.0 W and 2.15 %. The influences of inlet and back pressures on the performance of turbine were different. With constant inlet pressure and temperature, the mass flow rate kept almost unchanged after chocking, but the power continued to increase. Under allowable conditions, reducing back pressure of turbine played an important role in improving turbine performance.

A study of the optimal conditions for organic Rankine cycles coupled with vapour compression refrigeration using a rigorous approach based on the Helmholtz energy function

VCR-ORC systems combine an organic Rankine cycle (ORC) to produce energy from low-moderate temperature sources and a standard refrigeration cycle (VCRC). Accurate objective functions for the optimal performance of the system are developed based on the Helmholtz energy function and its derivatives. Moreover, the utility of two objective functions is analysed in the search for the optimal conditions of a VCR-ORC system. Finally, it presents a comparative analysis of several working fluids to give the directives in selecting an optimal working fluid and its operation optimal conditions. The method described above uses a set of refrigerants and the PC-SAFT EOS as the prediction model. The results presented in this work show that variables such as the condenser temperature, T1, are fundamental for the optimisation of VCR-ORC systems. Pentane and R1233zd have the best performance for this system. However, the fourth-generation refrigerant shows the best operational condition in all the indicators among the studied fluids despite its wet expansion in optimal operation. In the idealised VCR-ORC cycle, the optimal ORC efficiency links with the optimal COP of the cycle while the extracted heat links with the optimal mechanical work produced by the ORC.

Multi-criteria optimization of a new geothermal driven integrated power and hydrogen production system via a new Index: Economic sustainability (EcoSI)

This study investigates a new geothermal energy-driven hybrid system, including an organic Rankine cycle (ORC) for power generation and a proton exchange membrane electrolyzer (PEMEL) to improve the sustainability of issued geothermal energy sources. In this aim, 2400 designs were formed parametrically. The designs were optimized throughout the multi-criteria decision-making (MCDM) analysis named efficiency analysis technique with output satisficing (EATWOS). In the optimization, a new index named the economic sustainability index (EcoSI) was proposed as the objective function. EcoSI was then introduced into MCDM analysis along with the sustainability index (SI). Design 1–2-7–1-1 with a turbine inlet temperature of 100 °C and inlet pressure of 1950 kPa was determined as the optimal design. In this design, the optimal current density was determined as the minimum chosen value with 1000 A/m2. The power supply rate was determined as the minimum chosen value of 10 %. The temperatures of the production and re-injection wells were determined as 133.5 °C and 111.99 °C, respectively. The exergy efficiency and power generation rate of ORC were determined as 21.11 % and 12.113 MW, respectively. The hydrogen generation rate and exergy efficiency of PEMEL were determined as 0.0057003 kg/s and 48.76 %, respectively. The exergy efficiency of the overall system was determined as 19.92 %. The investment cost was determined as 332.57 $/h. Exergy destruction, fuel and product costs were determined at 38312.99 $/h, 48272.40 $/h, and 24240.05 $/h, respectively. The sustainability index (SI) was determined as 1.249, whereas the economic sustainability index (EcoSI) was determined as 1.260.

Desorption properties of the R600, R134a and their mixtures in several MOF structures: A molecular dynamics study

The efficiency of organic Rankine cycle is expected to be enhanced via using metal organic heat carriers. Thus, it is important to investigate the properties of organic working fluid in metal organic frameworks (MOFs). In this paper, molecular dynamics method was employed to study the desorption properties of R600, R134a, and their mixtures in MOF-5, IRMOF-16, and MOF-200 structures. The results show that the desorption capacity of pure working fluids are negatively correlated with their molecular size. In mixed refrigerant systems, the desorption of the working medium is competitive, and the higher the proportion of fluorine atoms in the system, the greater the desorption heat in IRMOF-16. It is noteworthy that the behavior of the desorption heat in the other two MOFs is diametrically opposed to this result. The desorption capacity is positively correlated with the average pore size, specific surface area, and porosity of the MOF. The self-diffusion coefficient of the working medium in MOF is inversely proportional to its molecular weight, but directly proportional to its molecular size and to the pore size of MOF.

Evaluating the thermal efficiency and net power output of ORC for three wet fluids

Low-grade heat can be successfully recovered from waste energy sources for power production by an organic Rankine cycle (ORC). In this work, reheat ORC has been studied with three different wet organic fluids. The performance of R1270, R152a and Cyclopropane has been modelled in an ORC operated by a source of heat of 413.15K. The reheat ORC model contains economizer, evaporator, superheater, reheater, two turbine, pump and condensers. With variable turbine inlet temperature and reheat pressure, the net power output and thermal efficiency have been estimated. The results show that there exists an optimum temperature at the turbine inlet maximizing . The increase of reheat pressure gives only a marginal growth in the cycle efficiency, but it rises the with about 16.88 %, 16.26 % and 13.23 % for R1270, R152a and cyclopropane respectively.

Design of the Organic Rankine Cycle for High-Efficiency Diesel Engines in Marine Applications

Over the past few years, fuel prices have increased dramatically, and emissions regulations have become stricter in maritime applications. In order to take these factors into consideration, improvements in fuel consumption have become a mandatory factor and a main task of research and development departments in this area. Internal combustion engines (ICEs) can exploit only about 15–40% of chemical energy to produce work effectively, while most of the fuel energy is wasted through exhaust gases and coolant. Although there is a significant amount of wasted energy in thermal processes, the quality of that energy is low owing to its low temperature and provides limited potential for power generation consequently. Waste heat recovery (WHR) systems take advantage of the available waste heat for producing power by utilizing heat energy lost to the surroundings at no additional fuel costs. Among all available waste heat sources in the engine, exhaust gas is the most potent candidate for WHR due to its high level of exergy. Regarding WHR technologies, the well-known Rankine cycles are considered the most promising candidate for improving ICE thermal efficiency. This study is carried out for a six-cylinder marine diesel engine model operating with a WHR organic Rankine cycle (ORC) model that utilizes engine exhaust energy as input. Using expander inlet conditions in the ORC model, preliminary turbine design characteristics are calculated. For this mean-line model, a MATLAB code has been developed. In off-design expander analysis, performance maps are created for different speed and pressure ratios. Results are produced by integrating the polynomial correlations between all of these parameters into the ORC model. ORC efficiency varies in design and off-design conditions which are due to changes in expander input conditions and, consequently, net power output. In this study, ORC efficiency varies from a minimum of 6% to a maximum of 12.7%. ORC efficiency performance is also affected by certain variables such as the coolant flow rate, heat exchanger’s performance etc. It is calculated that with the increase of coolant flow rate, ORC efficiency increases due to the higher turbine work output that is made possible, and the condensing pressure decreases. It is calculated that ORC can improve engine Brake Specific Fuel Consumption (BSFC) from a minimum of 2.9% to a maximum of 5.1%, corresponding to different engine operating points. Thus, decreasing overall fuel consumption shows a positive effect on engine performance. It can also increase engine power output by up to 5.42% if so required for applications where this may be deemed necessary and where an appropriate mechanical connection is made between the engine shaft and the expander shaft. The ORC analysis uses a bespoke expander design methodology and couples it to an ORC design architecture method to provide an important methodology for high-efficiency marine diesel engine systems that can extend well beyond the marine sector and into the broader ORC WHR field and are applicable to many industries (as detailed in the Introduction section of this paper).

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.

Mathematical modeling of a binary ORC operated with solar collectors. Case study—Ecuador

<abstract> <p>The present study is significant because it can contribute to developing sustainable energy strategies and expanding knowledge about renewable energies in Ecuador, specifically by modeling two modules: the thermal module (parabolic solar collectors and energy storage tank) and the Organic Rankine Cycle (ORC) module. The objective was to determine a region in Ecuador where the thermal module exhibits the highest efficiency for solar collectors. Subsequently, a detailed analysis of the ORC module was conducted, considering the working fluid, boiling temperature, condensation temperature, pinch point temperature, solar collector area, and the collector area-to-energy storage volume ratio (<italic>Ac/V</italic>). Finally, an economic analysis was performed based on the Net Present Value (NPV), Internal Rate of Return (IRR), and payback period of implementing this type of system. After conducting all the respective analyses in the thermal module, while considering the yearly average meteorological data of ten years (2012–2022), it was determined that due to its meteorological conditions, ambient temperature (14.7 ℃) and solar beam radiation (184.5 W/m<sup>2</sup>), the efficiency of the collectors in the Andean region of Ecuador is higher. This efficiency is further enhanced by using Therminol VP-1 as the thermal fluid, as it possesses better thermodynamic properties than the other fluids analyzed. Similarly, the ORC module analysis results determined that cyclohexane is the working fluid for the ORC, thereby leading to a higher ORC efficiency (25%) and overall system efficiency (20%). Finally, the system was optimized to maximize the IRR and minimize the <italic>A</italic>c/<italic>V</italic> of the collector for a nominal power of 92 kW. As a result, the optimal operating conditions of the system include a solar collector area of 1600 m<sup>2</sup>, an energy storage tank volume of 54 m<sup>3</sup>, an electricity production of 23757 MW/year, a total system efficiency of 22%, an IRR of 15.65% and a payback period of 9.81 years.</p> </abstract>

Determination of sensitivity and contribution ratios of parameters affecting Organic Rankine Cycle efficiency with multivariant optimization

Determination of sensitivity and contribution ratios of parameters affecting Organic Rankine Cycle efficiency with multivariant optimization

Determination of sensitivity and contribution ratios of parameters affecting Organic Rankine Cycle efficiency with multivariant optimization

Determination of sensitivity and contribution ratios of parameters affecting Organic Rankine Cycle efficiency with multivariant optimization

Parametric and economic analysis of high-temperature cascade organic Rankine cycle with a biphenyl and diphenyl oxide mixture

High-temperature organic Rankine cycle (ORC) systems have the potential to improve the heat-to-power conversion efficiency and expand the temperature range for heat recovery, heat battery and solar power generation. Restricted by the critical temperature of the commonly used organic working fluids, the current ORC technology has a maximum working temperature of around 300 °C. This paper proposes a high-temperature cascade organic Rankine cycle (CORC) system using a biphenyl and diphenyl oxide (BDO) mixture as the top cycle fluid and conventional organic fluids for the bottom cycle. The BDO mixture has excellent heat stability over a wide operation condition from 12 °C to 400 °C in single-phase and binary-phase states. However, at present a detailed study on the ORC using the mixture is lacking. In this paper, a parametric analysis of the high-temperature CORC system is conducted. A mathematical model based on the equivalent hot side temperature is built to simulate the ORC efficiency. The thermodynamic and exergetic performances of the novel CORC system under different bottom ORC working fluids, mixing chamber temperatures, evaporation temperatures, and condensation temperatures are investigated. The results show the maximum thermal efficiency of the CORC system is 38.74 % and 40.26 % at top ORC evaporation temperatures of 360 °C and 400 °C. The largest exergy destruction takes place in the heat exchanger between the top and bottom ORCs. Besides, the heat regenerators have a significant impact on the thermodynamic performance and can elevate the CORC efficiency by about 4 %. The proposed system has a higher efficiency and a lower equipment cost than conventional steam Rankine cycle at 400 °C while eliminating the challenges of wet steam turbines.