scholarly journals Addressing Industrial Waste Heat Supply Variability With Organic Rankine Cycle Systems Incorporating Thermal Energy Storage

Author(s):  
Bipul Krishna Saha ◽  
Basab Chakraborty ◽  
Rohan Dutta

Abstract Industrial low-grade waste heat is lost, wasted and deposited in the atmosphere and is not put to any practical use. Different technologies are available to enable waste heat recovery, which can enhance system energy efficiency and reduce total energy consumption. Power plants are energy-intensive plants with low-grade waste heat. In the case of such plants, recovery of low-grade waste heat is gaining considerable interest. However, in such plants, power generation often varies based on market demand. Such variations may adversely influence any recovery system's performance and the economy, including the Organic Rankine Cycle (ORC). ORC technologies coupled with Cryogenic Energy Storage (CES) may be used for power generation by utilizing the waste heat from such power plants. The heat of compression in a CES may be stored in thermal energy storage systems and utilized in ORC or Regenerative ORC (RORC) for power generation during the system's discharge cycle. This may compensate for the variation of the waste heat from the power plant, and thereby, the ORC system may always work under-designed capacity. This paper presents the thermo-economic analysis of such an ORC system. In the analysis, a steady-state simulation of the ORC system has been developed in a commercial process simulator after validating the results with experimental data for a typical coke-oven plant. Forty-nine different working fluids were evaluated for power generation parameters, first law efficiencies, purchase equipment cost, and fixed investment payback period to identify the best working fluid.

Author(s):  
Aristide Massardd ◽  
Gian Marid Arnulfi

In this paper three Closed Combined Cycle (C3) systems for underwater power generation are analyzed. In the first, the waste heat rejected by a Closed Brayton Cycle (CBC) is utilized to heat the working fluid of a bottoming Rankine Cycle; in the second, the heat of a primary energy loop fluid is used to heat both CBC and Rankine cycle working fluids; the third solution involves a Metal Rankine Cycle (MRC) combined with an Organic Rankine Cycle (ORC). The significant benefits of the Closed Combined Cycle concepts, compared to the simple CBC system, such as efficiency increase and specific mass reduction, are presented and discussed. A comparison between the three C3 power plants is presented taking into account the technological maturity of all the plant components.


Author(s):  
Jack T. Nguyen

A patent pending concept is presented for a dry, closed-cycle power plant cooling system employing low temperature organic Rankine cycle waste heat recovery (ORC-WHR) in combination with cool thermal energy storage (TES). It offers a compelling way for power plants to operate like conventional once-through cooling (OTC) — i.e., without an efficiency penalty due to heat rate increase experienced by state-of-the-art dry, wet, and hybrid cooling systems — while eliminating water consumption and attached negative environmental impact. Further, cool TES provides power plants the desirable capability and benefits associated with grid-scale energy storage. Key components of the concept are comprised of developed technology and field-proven equipment. Performance estimates to convert from OTC for the Diablo Canyon nuclear-powered steam electric generating facility located in central California are presented to illustrate the real benefits gained verses closed-cycle wet cooling.


2013 ◽  
Vol 597 ◽  
pp. 45-50
Author(s):  
Sławomir Smoleń ◽  
Hendrik Boertz

One of the key challenges on the area of energy engineering is the system development for increasing the efficiency of primary energy conversion and use. An effective and important measure suitable for improving efficiencies of existing applications and allowing the extraction of energy from previously unsuitable sources is the Organic Rankine Cycle. Applications based on this cycle allow the use of low temperature energy sources such as waste heat from industrial applications, geothermal sources, biomass, fired power plants and micro combined heat and power systems.Working fluid selection is a major step in designing heat recovery systems based on the Organic Rankine Cycle. Within the framework of the previous original study a special tool has been elaborated in order to compare the influence of different working fluids on performance of an ORC heat recovery power plant installation. A database of a number of organic fluids has been developed. The elaborated tool should create a support by choosing an optimal working fluid for special applications and become a part of a bigger optimization procedure by different frame conditions. The main sorting criterion for the fluids is the system efficiency (resulting from the thermo-physical characteristics) and beyond that the date base contains additional information and criteria, which have to be taken into account, like environmental characteristics for safety and practical considerations.The presented work focuses on the calculation and optimization procedure related to the coupling heat source – ORC cycle. This interface is (or can be) a big source of energy but especially exergy losses. That is why the optimization of the heat transfer between the heat source and the process is (besides the ORC efficiency) of essential importance for the total system efficiency.Within the presented work the general calculation approach and some representative calculation results have been given. This procedure is a part of a complex procedure and program for Working Fluid Selection for Organic Rankine Cycle Applied to Heat Recovery Systems.


2020 ◽  
Vol 142 (5) ◽  
Author(s):  
Fletcher Carlson ◽  
Jane H. Davidson

Abstract The intermittency of wind and solar energy can disrupt the dynamic balance utilities must maintain to meet fluctuating demand. This work examines the use of thermal energy storage (TES) to increase the operational flexibility of a baseload power plant and thus incentivize renewable energy and decarbonize the grid. A first and second law thermodynamic model of a nuclear power plant establishes the impacts of TES on the capacity factor and thermal efficiency of the plant. Four storage options, which are distinguished by the location within the cycle where steam is diverted for charging and whether discharge of the TES is via the primary or a secondary Rankine cycle, are considered. TES is compared to steam bypass, which is an alternative to provide baseload flexibility. TES is significantly better than steam bypass. The storage option with the greatest thermodynamic benefit is charged by diverting superheated steam at the outlet of the moisture separator/reheater (MSR) to the TES. The TES is discharged for peaking power through an optimized secondary cycle. TES increases the capacity factor as much as 15% compared to steam bypass at representative charging mass flowrates. The storage option that diverts steam from the steam generator to charge the TES and discharges the TES to the primary cycle extends the discharge power to a lower range and does not require a secondary cycle. In this case, the capacity factor and efficiency are as much as 8% greater than that of steam bypass.


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