A parametric analysis to evaluate the performance metrics of power generation system involving Trilateral Flash Cycle using three different working fluids for low grade waste heat

Trilateral Flash Cycle (TFC): a promising thermodynamic cycle for low grade heat to power generation

Exergo-economic analysis of different power-cycle configurations driven by heat recovery of a gas engine

Despite the current energy crisis, a large amount of low grade heat (below 100oC) is being wasted for the lack of cost effective energy conversion technology. In the case of the conventional Organic Rankine Cycle (ORC) based geothermal power stations, only about 20% of available heat can be utilised due to a technological limitation as there is a phase change in the working fluid involved during the addition of heat which decreases utilisation effectiveness of the system. Therefore, in this paper, a trilateral flash cycle (TFC) based system has been studied to find out its prospect for utilizing more power from the same heat resources as the ORC. The TFC is a thermodynamic cycle that heats the working fluid as a saturated liquid from which it starts its expansion stage. The flash expansion is achieved by feeding the saturated high-pressured liquid working fluid through a convergent-divergent nozzle at which point it undergoes a flash expansion in the low-pressure environment of the generator housing. The momentum of the working fluid is extracted via a Pelton wheel and the cycle is completed with working fluid condensation and pressurisation. The analytical comparative study between the ORC and TFC based system shows that the TFC has about 50% more power generation capability and almost zero contribution on global warming.

Over the last decade due to rapid global population growth and industrialisation of developing economies, the demand for freshwater and energy is rising, placing significant stress on these vital resources. Seawater desalination has been widely used as a solution to water scarcity, but it is energy intensive. At the same time, low and medium-grade heat sources are readily available, and has potential to supplement mainstream renewable energy sources, such as solar and wind due to their intermittent nature. Despite the availability of low and medium grade heat, its utilization remains limited due to thermodynamic inefficiencies and economic feasibility. Considering this, researchers have focused their efforts to develop more sustainable energy and water production technologies. While the broad aim of this paper it to investigate the sustainable water desalination and power generation technologies, the paper focuses on examining their integration to improve energy resource utilisation through combined desalination and power generation systems. A comprehensive review and comparative analysis of technologies, including Rankine cycle-based power generation, membrane-based processes, and hybrid systems, in conjunction with desalination techniques like reverse osmosis, membrane distillation, and multiple-effect distillation is conducted. Power generation from low grade thermal energy sources is inherently inefficient due to the thermodynamics limitations and hence not many pilot/commercial applications have been realised over the years. Similarly, thermal desalination with low grade thermal energy sources has low recovery due to limitations maximum stages. Furthermore, both these systems need comparatively large heat exchangers due to low temperature differentials, make the systems expensive leading to high cost per unit of power and water. The paper compares different configurations of combined desalination power generation systems available in the literature. The literature shows that under the same input parameters, a combined systems operating on trilateral flash cycle will produce 2.7 time more freshwater production compared to other configurations, while a Rankine cycle based combined system will provide 45.2 % more power. Literature shows the potential of membrane based combined desalination and power generation, but the currently reported power densities for such systems of 0.3 to 0.6 W/m2 is not viable and must be increase the power density must increase by at least one order of magnitude to be net positive producer of power. The paper provides several suggestions/directions for future work.

Power Generation from Low Grade Heat Using Trilateral Flash Cycle

Techno-economic and 4E comparisons of various thermodynamic power cycles for low-medium grade heat recovery

This paper provides an overview of a one-dimensional modelling methodology for equipment and systems for heat to power conversion based on a staggered grid space discretization and implemented in the commercial software GT-SUITE®. Particular attention is given to a newly developed modelling procedure for twin-screw machines that is based on a chamber modelling approach and considers leakage paths between cells and with the casing. This methodology is then applied to a low-grade heat to power conversion system based on a Trilateral Flash Cycle (TFC) equipped with two parallel two-phase twin-screw expanders and a control valve upstream of the machines to adapt the fluid quality for an optimal expander operation. The standalone expander model is used to generate performance maps of the machine, which serve as inputs for the TFC system model. Parametric analyses are eventually carried out to assess the impact of several operating parameters of the TFC unit on the recovered power and cycle thermal efficiency. The study shows that the most influencing factors on the TFC system’s performance are the inlet temperature of the heat source and the expander speed. While the first depends on the topping industrial process, the expander speed can be used to optimize and control the TFC system operation also in transient or off-design operating conditions.

Experimental study on the prospect of low-temperature heat to power generation using Trilateral Flash Cycle (TFC)

Trilateral Flash Cycle for Recovery of Power from a Finite Low-Grade Heat Source

Prospects of Power Generation from Low Grade Heat Resources through Trilateral Flash Cycle (TFC) Using Impulse Turbine

Experimental study of converging-diverging nozzle to generate power by Trilateral Flash Cycle (TFC)

Multi-aspect assessment and optimization of a poly-generation layout composed of a geothermal power plant and a wind turbine

Exergo-economic comparison of waste heat recovery cycles for a cement industry case study

An experimental validation on laboratory scale has been conducted to investigate and to compare two thermodynamic cycles, Trilateral Flash Cycle (TFC) and Organic Rankine Cycle (ORC). The research covers the heat engine utilizing a hydrothermal resource to compare the performance of TFC and ORC. This research would help to analysis the thermal efficiency and power efficiency for both cycles. TFC shows a higher power production than in ORC for the same applied parameters. ORC, however, can be operated at lower rotational speed than for TFC. This project could help, also, to evaluate the current two phase screw expander for both cycles. It is concluded to propose a larger heat exchanger for TFC as the heat recovery can be more reliable in this cycle than in ORC. This research can be applied to generate electrical power from hydrothermal resources such as geothermal energy and solar thermal.

Investigation of the performance of modified organic Rankine cycles (ORCs) and modified trilateral flash cycles (TFCs) assisted by a solar pond