Showing papers on "Thermodynamic cycle published in 2017"
TL;DR: In this paper, a rotating detonation combustion engine was evaluated using the Toolbox for the Modeling and Analysis of Thermodynamic Systems (TAS) to evaluate precisely the thermodynamic and non-isentropic processes across the entire engine.
138 citations
TL;DR: In this article, a comparison of three cycles in terms of energy and exergy analyses of their systems is presented, and the results show that a split cycle can produce the highest power of the three systems considered over a wide range of operating conditions.
133 citations
TL;DR: In this article, a combined cycle coupling supercritical CO2 recompression and regenerative cycle is proposed to recover the marine gas turbine exhaust heat, and improve the ship part-load thermal efficiency.
121 citations
TL;DR: In this paper, a novel combined flash-binary cycle is proposed for power generation from Sabalan geothermal wells in Iran, considering the wellhead temperature and pressure differences of existing wells.
117 citations
TL;DR: In this article, the authors focused on subcritical and transcritical ORCs using R1234ze(E) driven by the 100-200°C hot water without the outlet temperature limit, and the optimal cycle type (subcritical or transcritical), optimized cycle parameters (turbine inlet temperature and turbine inlet pressure), and system performance were studied in the view of the maximum system net power output for the per mass flow rate heat source fluid.
101 citations
TL;DR: In this article, a Kalina-based combined cooling and power (CCP) cycle driven by low-grade heat source was investigated, and a performance optimization was conducted by genetic algorithm to obtain the optimum exergy efficiency.
82 citations
TL;DR: In this paper, the performance comparison of low-grade organic Rankine cycle (ORC) using R245fa, R123 and their mixtures has been investigated, where the heat source temperature is set to be 120°C, while the mass flow rate is controlled by adjusting the pump frequency.
75 citations
TL;DR: In this article, a combined cooling, heating and power cycle is proposed consisting of three sections of gas turbine and heat recovery steam generator cycle, Regenerative organic Rankine cycle, and absorption refrigeration cycle.
65 citations
TL;DR: In this paper, the backpressure effect of an organic Rankine cycle (ORC) evaporator on the exhaust line of a turbocharged, V12 heavy duty diesel engine, for typical marine and power generation applications has been investigated using the commercial software Ricardo WAVE.
63 citations
TL;DR: In this article, a new ammonia-water cogeneration system is proposed to produce power and refrigeration outputs simultaneously, which combines Kalina power cycle and ejector refrigeration cycle.
59 citations
TL;DR: In this article, an exergy analysis of a two-parallel-step organic Rankine cycle (ORC) for waste heat recovery from an internal combustion engine (ICE) is performed.
TL;DR: In this paper, the authors reviewed the efforts in the past few decades to apply Rankine Cycle to on-road vehicles, specifically passenger cars, and identified the characteristics of the waste heat sources found in vehicles and the constraints put on the automotive RC application.
Abstract: Rankine Cycle (RC) is a thermodynamic cycle that converts thermal energy into mechanical work, which is commonly found in thermal power generation plants. Recently, there have been many studies focusing on applying Rankine Cycle to recover low-grade waste heat. On-road vehicles, which convert around one third of the fuel energy into useful mechanical energy for propulsion, are moving energy conversion systems that generate considerable waste heat. It is found from prior research that the Rankine Cycle has great potential in automobile waste heat harvesting applications. However, in contrast with other low-grade waste heat applications, vehicles have limited space for the RC system integration, and the waste heat is relatively unsteady. In this work, the efforts in the past few decades to apply RC to on-road vehicles, specifically passenger cars, are reviewed. Characteristics of the waste heat sources found in vehicles and the constraints put on the automotive RC application are identified. Rankine Cycle architectures, system components, and working fluids suitable to different applications are summarized, which provides a guideline for future RC system design in automobiles. Lastly, a new concept and case study into the future application of Rankine Cycle to vehicle waste heat recovery (WHR) is provided.
TL;DR: In this paper, a reduced-order model of the thermodynamic cycle within a rotating detonation engine system is presented with an emphasis on the identification of the parameters that drive performance and the valuations.
Abstract: Reduced-order modeling of the thermodynamic cycle within a rotating detonation engine system is presented with an emphasis on the identification of the parameters that drive performance and the val...
TL;DR: At low temperatures, when the magnetic fields of the isothermal processes are located on both sides of the critical point of the QPT, the cycle reaches maximum efficiency, and the Carnot efficiency can be achieved.
Abstract: With the Lipkin-Meshkov-Glick (LMG) model as an illustration, we construct a thermodynamic cycle composed of two isothermal processes and two isomagnetic field processes, and we study the thermodynamic performance of this cycle accompanied by the quantum phase transition (QPT). We find that for a finite particle system working below the critical temperature, the efficiency of the cycle is capable of approaching the Carnot limit when the external magnetic field λ_{1} corresponding to one of the isomagnetic processes reaches the cross point of the ground states' energy level, which can become the critical point of the QPT in the large-N limit. Our analysis proves that the system's energy level crossings at low-temperature limits can lead to a significant improvement in the efficiency of the quantum heat engine. In the case of the thermodynamics limit (N→∞), the analytical partition function is obtained to study the efficiency of the cycle at high- and low-temperature limits. At low temperatures, when the magnetic fields of the isothermal processes are located on both sides of the critical point of the QPT, the cycle reaches maximum efficiency, and the Carnot efficiency can be achieved. This observation demonstrates that the QPT of the LMG model below critical temperature is beneficial to the thermodynamic cycle's operation.
TL;DR: In this article, a thermodynamic study of newly suggested supercritical carbon dioxide (s-CO2) cycle layouts using an isothermal compressor is presented, and the calculations highlight that it reduces the compression work significantly over other representative working fluids.
TL;DR: In this paper, a new adsorptive cycle for upgrading the ambient heat is suggested and briefly analyzed, where regeneration of adsorbent is performed by dropping the vapour pressure over adorbent at a constant temperature, rather than by heating as usual.
TL;DR: In this article, two different engine operating conditions are chosen for system design and compared by net power output at off-design conditions to reveal the influence of design condition selection on CTPC systems.
TL;DR: In this paper, a complementary combined cooling, heating and power- organic Rankine cycle system (CCHP-ORC) with a ground source heat pump is configured to reduce the mismatch between energy supply and demand.
TL;DR: In this article, an organic Rankine cycle process and its pure working fluid are designed simultaneously for waste heat recovery of the exhaust gas from a marine diesel engine, which can overcome design issues caused by the high sensitivity between the fluid and cycle design variables and otherwise high resource demands.
TL;DR: In this article, the effect of compressor pressure ratio (RP) on the thermodynamic performances of ammonia-water combined cycle through energy and exergy destruction, enthalpy temperature, yields, and flow velocity was investigated.
TL;DR: In this article, the authors investigated the combined Rankine power and the absorption cooling cycles, where the working fluid used in this cycle is the binary liquid mixture of water and ammonia.
TL;DR: In this paper, a parametric study of the effects of the influential variables, including charged pressure, heating temperature, regenerator porosity, engine rotation speed, number of heating pipes, and working fluid, on P-V diagrams of the thermodynamic cycles is performed extensively.
TL;DR: In this article, the performance of an organic Rankine cycle using R123 and a scroll expander has been investigated with varying working fluid mass flow rates ranging from 0.124 to 0.222 kg/s and heat source temperatures ranging from 383.15 to413.15 K.
TL;DR: In this article, a multi-objective optimization problem addressing an organic Rankine Cycle system is solved with consideration for the electric efficiency and overall heat exchangers area as quantities that should be optimized.
TL;DR: In this article, the authors investigated four design Joule-Brayton configurations at increasing complexity: simple regenerative, with recompression, with reheating, with re-compression and reheating.
TL;DR: In this article, the authors propose a thermodynamic cycle in which the gas of electrons in the p phase serves as the working substance, and the interface between the p and n phases acts as a self-oscillating piston that modulates the absorption of heat from the photons so that it may perform a net positive work during a complete cycle of its motion, in accordance with the laws of thermodynamics.
TL;DR: In this article, a model for the description of the thermal efficiency of a lunar surface nuclear reactor power system with eight free piston Stirling engines to generate nominal electrical power of 100kWe was developed.
01 Jan 2017
TL;DR: In this article, the authors discuss the mutual correlation between the chemical structure and the thermal stability of working fluids, and a useful methodology to determine temperature limits for the working fluids is presented and discussed.
Abstract: Each organic fluid is characterized by thermal decomposition above a specific temperature called the thermal stability limit. The correct evaluation of this limit is extremely important to avoid massive cracking phenomena which can cause the fouling of heat exchangers' surfaces, material erosion, and changes of fluid thermodynamic properties. After a brief discussion about the mutual correlation between the chemical structure and the thermal stability of working fluids, a review of the main experimental data available is worked out. Finally, experimental apparatus and a useful methodology to determine temperature limits for the working fluids is presented and discussed.
TL;DR: This work proposes a framework to describe pattern manipulators-devices that convert thermodynamic work to patterns or vice versa-and uses them to build a "pattern engine" that facilitates a thermodynamic cycle of pattern creation and consumption.
Abstract: Many organisms capitalize on their ability to predict the environment to maximize available free energy and reinvest this energy to create new complex structures. This functionality relies on the manipulation of patterns-temporally ordered sequences of data. Here, we propose a framework to describe pattern manipulators-devices that convert thermodynamic work to patterns or vice versa-and use them to build a "pattern engine" that facilitates a thermodynamic cycle of pattern creation and consumption. We show that the least heat dissipation is achieved by the provably simplest devices, the ones that exhibit desired operational behavior while maintaining the least internal memory. We derive the ultimate limits of this heat dissipation and show that it is generally nonzero and connected with the pattern's intrinsic crypticity-a complexity theoretic quantity that captures the puzzling difference between the amount of information the pattern's past behavior reveals about its future and the amount one needs to communicate about this past to optimally predict the future.
TL;DR: In this article, a large-scale screening based on computational chemistry and thermodynamic process simulation is coupled with a multi-criteria evaluation to identify an optimal working fluid which is flexible in terms of application and condensing temperature and which is applicable in real systems.