Development of the Trilateral Flash Cycle System: Part 1: Fundamental Considerations

Author(s):  
I K Smith

The world market for systems for power recovery from low-grade heat sources is of the order of £1 billion per annum. Many of these sources are hot liquids or gases from which conventional power systems convert less than 2.5 per cent of the available heat into useful power when the fluid is initially at a temperature of 100° C rising to 8–9 per cent at an initial temperature of 200°C. Consideration of the maximum work recoverable from such single-phase heat sources leads to the concept of an ideal trilateral cycle as the optimum means of power recovery. The trilateral flash cycle (TFC) system is one means of approaching this ideal which involves liquid heating only and two-phase expansion of vapour. Previous work related to this is reviewed and details of analytical studies are given which compare such a system with various types of simple Rankine cycle. It is shown that provided two-phase expanders can be made to attain adiabatic efficiencies of more than 75 per cent, the TFC system can produce outputs of up to 80 per cent more than simple Rankine cycle systems in the recovery of power from hot liquid streams in the 100–200°C temperature range. The estimated cost per unit net output is approximately equal to that of Rankine cycle systems. The preferred working fluids for TFC power plants are light hydrocarbons.

1984 ◽  
Vol 106 (4) ◽  
pp. 737-742 ◽  
Author(s):  
A. I. Kalina

A new thermodynamic energy cycle has been developed using a multicomponent working agent. This cycle is designed to replace the currently used Rankine Cycle as a bottoming cycle for a combined-cycle energy system as well as for generating electricity using low-temperature heat sources. Several combined power systems based on this cycle have been designed and cost-estimated. The efficiency of this cycle is from 1.6 to 1.9 times higher than that of the Rankine Cycle system, at the same border conditions. The investment cost per unit of power output for this cycle is lower than that for the Rankine Cycle system in approximately direct proportion to the energy advantage. The application of this cycle as a bottoming cycle in combined-cycle systems involves the use of an energy system which utilizes heat from the exhaust of a gas turbine, resulting in an increase in overall efficiency of up to 20 percent above the efficiency of the combined systems using the Rankine bottoming cycle. As a result, a thermal efficiency in the range of 50–52 percent can be achieved using a conventional gas turbine. The project to build the first experimental installation is now in progress. This installation is to become operational at the end of 1984.


Author(s):  
H. Leibowitz ◽  
I. K. Smith ◽  
N. Stosic

The growing need to recover power from low grade heat sources, has led to a review of the possibilities for producing systems for cost effective power production at outputs as little as 20-50kWe. It is shown that by utilizing the full potential of screw expanders instead of turbines, it is possible to produce Organic Rankine Cycle (ORC) systems at these outputs, which can be installed for a cost in the range of $1500 to $2000 /kWe of net output. This low capacity cost combined with the ORC's fuel-free specification results in a very favorable value proposition.


Solar Energy ◽  
2002 ◽  
Author(s):  
Ju¨rgen Dersch ◽  
Michael Geyer ◽  
Ulf Hermann ◽  
Scott A. Jones ◽  
Bruce Kelly ◽  
...  

Parabolic trough solar technology has over 125 plant-years of successful operation at nine commercial Solar Electric Generating Systems (SEGS) power plants that are operating near Barstow, California. These solar plants utilize conventional steam Rankine turbine-generator systems, and as a result most people associate parabolic trough solar technology with steam Rankine cycle power plants. Although these plants are clearly optimized for their particular application, other power cycle designs may be appropriate in other situations. Of particular interest is the integration of parabolic trough solar technology with combined cycle power plant technology, a configuration called the integrated solar combined cycle system (ISCCS). Four potential projects in India, Egypt, Morocco, and Mexico are considering the ISSCS configuration. This paper compares the performance, cost, and carbon emissions of ISCCS and SEGS plants with a standard combined cycle plant.


2019 ◽  
Vol 116 ◽  
pp. 00035
Author(s):  
Piotr Kolasiński

Some of the heat sources (such as e.g. waste or renewable), are characterized by floating thermal and output characteristics. Thus, their application for powering vapor power plants, such as ORCs, which should utilize the heat sources having steady thermal and output characteristics is difficult. The floating heat source characteristics may potentially be improved using the heat storage devices providing the thermal energy accumulation at stable output and temperature level. Heat storage device can be adopted as a e.g. steady-level heat source for ORC system. In this paper different applications of the heat storage devices in ORCs were proposed and the results of experiments on powering the ORC system via heat storage device are presented. The results showed that adopting the heat storage devices for powering the ORC systems is possible and it is a promising way of utilizing the waste and renewable heat sources featuring floating characteristics.


2021 ◽  
Vol 9 ◽  
Author(s):  
Enhua Wang ◽  
Ningjian Peng ◽  
Mengru Zhang

Improving energy efficiency and reducing carbon emissions are crucial for the technological advancement of power systems. Various carbon dioxide (CO2) power cycles have been proposed for various applications. For high-temperature heat sources, the CO2 power system is more efficient than the ultra-supercritical steam Rankine cycle. As a working fluid, CO2 exhibits environmentally friendly properties. CO2 can be used as an alternative to organic working fluids in small- and medium-sized power systems for low-grade heat sources. In this paper, the main configurations and performance characteristics of CO2 power systems are reviewed. Furthermore, recent system improvements of CO2 power cycles, including supercritical Brayton cycles and transcritical Rankine cycles, are presented. Applications of combined systems and their economic performance are discussed. Finally, the challenges and potential future developments of CO2 power cycles are discussed. CO2 power cycles have their advantages in various applications. As working fluids must exhibit environmentally-friendly properties, CO2 power cycles provide an alternative for power generation, especially for low-grade heat sources.


Author(s):  
I K Smith ◽  
R Pitanga Marques da Silva

The trilateral flash cycle system is a proposed means of power recovery from single-phase low-grade heat sources. Its feasibility depends on the efficient adiabatic expansion of light hydrocarbons from the saturated liquid phase into the two-phase region. Such a process is performed most effectively with a Lysholm twin-screw expander when the exhausted vapour is wet. At higher temperatures, when multi-stage expansion is required, working fluids may be found which complete the process as dry saturated vapour. It is shown that at condensing temperatures of 0–50°C, this is possible with a mixture of n-pentane and 2,2–dimethylpropane (neopentane) for fluid inlet temperatures in the 150–180 °C range. A radial inflow turbine may then be used in place of a screw for the last stage. With such an arrangement, expander adiabatic efficiencies of up to 85 per cent have been predicted for power outputs in excess of 5 MW. The method of fluid property estimation is described and its accuracy confirmed by experiment.


2016 ◽  
Vol 64 ◽  
pp. 790-805 ◽  
Author(s):  
Huixing Zhai ◽  
Qingsong An ◽  
Lin Shi ◽  
Vincent Lemort ◽  
Sylvain Quoilin

Author(s):  
Antonio Agresta ◽  
Antonella Ingenito ◽  
Roberto Andriani ◽  
Fausto Gamma

Following the increasing interest of aero-naval industry to design and build systems that might provide fuel and energy savings, this study wants to point out the possibility to produce an increase in the power output from the prime mover propulsion systems of aircrafts. The complexity of using steam heat recovery systems, as well as the lower expected cycle efficiencies, temperature limitations, toxicity, material compatibilities, and/or costs of organic fluids in Rankine cycle power systems, precludes their consideration as a solution to power improvement for this application in turboprop engines. The power improvement system must also comply with the space constraints inherent with onboard power plants, as well as the interest to be economical with respect to the cost of the power recovery system compared to the fuel that can be saved per flight exercise. A waste heat recovery application of the CO2 supercritical cycle will culminate in the sizing of the major components.


Author(s):  
Huijuan Chen ◽  
D. Yogi Goswami ◽  
Muhammad M. Rahman ◽  
Elias K. Stefanakos

A supercritical Rankine cycle using zeotropic mixture working fluids for the conversion of low-grade heat into power is proposed and analyzed in this paper. A supercritical Rankine cycle does not go through two-phase region during the heating process. By adopting zeotropic mixtures as the working fluids, the condensation process happens non-isothermally. Both of the features create a potential in reducing the irreversibility and improving the system efficiency. A comparative study between an organic Rankine cycle and the proposed supercritical Rankine cycle shows that the proposed cycle improves the cycle thermal efficiency, exergy efficiency of the heating and the condensation processes, and the system overall efficiency.


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