Transient Thermodynamic Modeling of Air Cooler in Supercritical CO2 Brayton Cycle for Solar Molten Salt Application

2020 ◽  
Vol 143 (2) ◽  
Author(s):  
Ankur Deshmukh ◽  
Jayanta Kapat ◽  
Akshay Khadse
Keyword(s):  
Carbon Dioxide ◽  
Air Temperature ◽  
Heat Exchangers ◽  
Dynamic Simulations ◽  
Power Cycle ◽  
Air Cooler ◽  
Temperature Operating ◽  
And Control ◽  
Start Ups ◽  
Transient Operations

Abstract Supercritical carbon dioxide Brayton power cycle is getting commercially attractive for power generation due to numerous advantages like zero water usage, compactness, low environmental emission, and potential to reach high thermal efficiency at lower costs. A typical recuperated closed cycle consists of three heat exchangers (main heat exchanger, cooler, and recuperator) and two turbomachinery (turbine and compressor). Rapid changes in ambient temperature, operating loads, start-ups, and shutdowns affect the performance and operation of the turbomachinery and heat exchangers. The purpose of this research article is to study the thermodynamic parameters of the air cooler during transient operations by running dynamic simulations. Magnitude of change in carbon dioxide temperature due to change in air temperature is calculated. The simulation is a setup by having a steady-state design of 100 MWe cycle with operating temperature of 700 °C and pressure of 250 bar. Dynamic simulations are done using lms amesim. Transients studied in this article include: (i) step variation, (ii) standard variation, and (iii) linear variation of air temperature. This study thus serves as a framework to develop a design and control basis governed by transient scenarios.

Transient Thermodynamic Modeling of Air Cooler in Supercritical CO2 Brayton Cycle for Solar Molten Salt Application

2019 ◽  
Author(s):  
Ankur Deshmukh ◽  
Jayanta Kapat ◽  
Akshay Khadse
Keyword(s):  
Molten Salt ◽  
Heat Exchangers ◽  
Supercritical Co2 ◽  
Water Discharge ◽  
Transient Behavior ◽  
Operating Conditions ◽  
Air Cooler ◽  
Temperature Operating ◽  
Transient Study ◽  
Start Ups

Abstract Supercritical CO2 Brayton power cycle is getting commercially attractive for power generation due to its numerous advantages like zero water discharge, compactness, low environmental emission and potential to reach high thermal efficiency at lower costs. A typical recuperated sCO2 closed cycle consists of three heat exchangers (main heat exchanger, cooler and recuperator) and two turbomachinery (sCO2 turbine and sCO2 compressor). The cooler which can use air or water as heat sink is the focus of this study. The purpose of the paper is investigation of behavior of thermodynamic parameters of cooler during transient operations. In this study, dynamic simulation is performed to analyze the transient behavior of air cooler in sCO2 cycle using molten salt as heat source from solar energy. Transient study is critical to understand the thermodynamic behavior of each system with time. Rapid changes in ambient temperature, operating loads, start-ups and shutdowns affect the performance of the turbomachinery and heat exchangers. The change in the thermal performance of air cooler with the change in boundary conditions is demonstrated here. The simulation is setup by having a steady state design of 100MWe sCO2 cycle with operating temperature of 700°C and pressure of 250 barA. Dynamic calculations are done using LMS AMESim. Transients studied in this paper include (i) step variation (ii) standard variation (iii) linear variation of air temperature. This work thus serves as a framework to develop a design basis for sCO2 cycle components as a function of transient operating conditions.

Pinch Point Analysis of Air Cooler in Supercritical Carbon Dioxide Brayton Cycle Operating Over Ambient Temperature Range

2020 ◽  
Vol 142 (5) ◽  
Author(s):  
Ankur Deshmukh ◽  
Jayanta Kapat
Keyword(s):  
Carbon Dioxide ◽  
Supercritical Carbon Dioxide ◽  
Water Discharge ◽  
Ambient Air ◽  
Operating Conditions ◽  
Pinch Point ◽  
Power Cycle ◽  
Air Cooler ◽  
Set Up ◽  
Supercritical Carbon

Abstract The supercritical carbon dioxide Brayton power cycle is getting commercially attractive for power generation due to its numerous advantages like zero water discharge, compactness, and low environmental emission and potential to reach high thermal efficiency. A typical recuperated closed cycle consists of three heat exchangers (main heat exchanger, cooler, and recuperator) and two turbomachinery (turbine and compressor). The cooler using ambient air for cooling is the focus of this study. The steady-state air cooler model is set up to study the effect of air cooler size on cycle efficiency. The effect of change in the ambient air temperature on the air cooler pinch point for different air cooler sizes is analyzed using the transient air cooler model. The simulation is set up for the design of the approximately 100 MWe cycle with an operating temperature of 700 °C and a pressure of 250 bar. Transient calculations are done using LMS AMESim. LMS AMESim is the Siemens PLM commercially available software. This work thus serves as a framework to develop a basis for the design of the air cooler in the power cycle as a function of transient operating conditions.

Response of a Compact Recuperator to Thermal Transients in a Supercritical Carbon Dioxide Brayton Cycle

2017 ◽  
Author(s):  
Eric M. Clementoni ◽  
Timothy L. Cox ◽  
Martha A. King
Keyword(s):  
Carbon Dioxide ◽  
Supercritical Carbon Dioxide ◽  
Heat Exchangers ◽  
High Surface ◽  
Integrated System ◽  
Compact Heat Exchangers ◽  
Power Cycle ◽  
Thermal Transients ◽  
Wide Range ◽  
Supercritical Carbon

Supercritical carbon dioxide (sCO2) power cycle designs are typically highly recuperated, transferring heat from the high temperature turbine exhaust stream to the compressor discharge stream thereby increasing overall cycle efficiency. Compact heat exchangers are preferred for this application due to their high surface area-to-volume ratio enabling much smaller heat exchangers as compared to conventional designs. However, compact heat exchangers have a higher metal density than conventional heat exchangers which could result in thermal lag during rapid temperature transients. The Naval Nuclear Laboratory has been operating the Integrated System Test (IST) with the objective of demonstrating the ability to operate and control an sCO2 Brayton power cycle over a wide range of conditions. Rapid turbomachinery startups and power transients result in thermal transients on the recuperator. This paper presents thermal transients observed in the IST recuperator during loop startup and power transients and illustrates the time to achieve thermal equilibrium following the transients.

scholarly journals Fault Simulations in a Multiterminal High Voltage DC Network with Modular Multilevel Converters Using Full-Bridge Submodules

Energies ◽  
2021 ◽  
Vol 14 (6) ◽  
pp. 1653
Author(s):  
Ioan-Cătălin Damian ◽  
Mircea Eremia ◽  
Lucian Toma
Keyword(s):  
High Voltage ◽  
Energy Resource ◽  
Fault Analysis ◽  
Renewable Energy Resource ◽  
Dynamic Simulations ◽  
Multilevel Converters ◽  
Strong Focus ◽  
Modular Multilevel Converters ◽  
Overhead Power Lines ◽  
And Control

The concept of high-voltage DC transmission using a multiterminal configuration is presently a central topic of research and investment due to rekindled interest in renewable energy resource integration. Moreover, great attention is given to fault analysis, which leads to the necessity of developing proper tools that enable proficient dynamic simulations. This paper leverages models and control system design techniques and demonstrates their appropriateness for scenarios in which faults are applied. Furthermore, this paper relies on full-bridge submodule topologies in order to underline the increase in resilience that such a configuration brings to the multiterminal DC network, after an unexpected disturbance. Therefore, strong focus is given to fault response, considering that converters use a full-bridge topology and that overhead power lines connect the terminals.

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