A new concept in thermal engineering optimization : the pericritical cycle with multi-heating and its application to concentrating solar power

Portillo, González; Francisco, Luis

doi:10.20868/upm.thesis.56492

Cited by 3 publications

(3 citation statements)

References 57 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…where δ w mc /w t is the variation of the dimensionless main compression work of the sCO 2 -mixtures respect to the pure s-CO 2 , δ w rc /w t is the variation of the dimensionless recompression work of the sCO 2 -mixtures respect to the pure s-CO 2 , δ ∆h a /w t is the variation of the dimensionless additional enthalpy of the sCO 2 -mixtures respect to the pure s-CO 2 , and δ total is the total variation of the dimensionless cycle work of the sCO 2 -mixtures respect to the pure s-CO 2 . It has been observed that the cycle efficiency increases when δ total increases [40]. Therefore, the influence of the dimensionless variables w mc /w t , w rc /w t and ∆h a /w t on the cycle efficiency can be displayed in Figure 7.…”

Section: Results Of 'Group A' Mixtures (Substances For Reducing the Cmentioning

confidence: 95%

Supercritical CO2 Mixtures for Advanced Brayton Power Cycles in Line-Focusing Solar Power Plants

2019

View full text Add to dashboard Cite

This work quantifies the impact of using sCO2-mixtures (s-CO2/He, s-CO2/Kr, s-CO2/H2S, s-CO2/CH4, s-CO2/C2H6, s-CO2/C3H8, s-CO2/C4H8, s-CO2/C4H10, s-CO2/C5H10, s-CO2/C5H12 and s-CO2/C6H6) as the working fluid in the supercritical CO2 recompression Brayton cycle coupled with line-focusing solar power plants (with parabolic trough collectors (PTC) or linear Fresnel (LF)). Design parameters assessed are the solar plant performance at the design point, heat exchange dimensions, solar field aperture area, and cost variations in relation with admixtures mole fraction. The adopted methodology for the plant performance calculation is setting a constant heat recuperator total conductance (UAtotal). The main conclusion of this work is that the power cycle thermodynamic efficiency improves by about 3–4%, on a scale comparable to increasing the turbine inlet temperature when the cycle utilizes the mentioned sCO2-mixtures as the working fluid. On one hand, the substances He, Kr, CH4, and C2H6 reduce the critical temperature to approximately 273.15 K; in this scenario, the thermal efficiency is improved from 49% to 53% with pure s-CO2. This solution is very suitable for concentrated solar power plants coupled to s-CO2 Brayton power cycles (CSP-sCO2) with night sky cooling. On the other hand, when adopting an air-cooled heat exchanger (dry-cooling) as the ultimate heat sink, the critical temperatures studied at compressor inlet are from 318.15 K to 333.15 K, for this scenario other substances (C3H8, C4H8, C4H10, C5H10, C5H12 and C6H6) were analyzed. Thermodynamic results confirmed that the Brayton cycle efficiency also increased by about 3–4%. Since the ambient temperature variation plays an important role in solar power plants with dry-cooling systems, a CIT sensitivity analysis was also conducted, which constitutes the first approach to defining the optimum working fluid mixture for a given operating condition.

show abstract

Section: Results Of 'Group A' Mixtures (Substances For Reducing the Cmentioning

confidence: 95%

Supercritical CO2 Mixtures for Advanced Brayton Power Cycles in Line-Focusing Solar Power Plants

2019

View full text Add to dashboard Cite

show abstract

“…S-CO 2 inlet and outlet temperatures are determined by the power cycle configuration and particle inlet and outlet temperatures are inputs in the EES code. For the calculation of the conductance, the heat exchanger is discretized into N HX sub-heat exchangers with the same heat duty

, and the sum of sub-heat exchanger conductances UA i is the total conductance, UA [ 29 ]:

where

is the logarithmic mean temperature difference.…”

Section: Modelmentioning

confidence: 99%

Techno-Economic Optimization of CSP Plants with Free-Falling Particle Receivers

González-Portillo

Albrecht

2021

Entropy

View full text Add to dashboard Cite

Particle receivers are one of the candidates for the next generation of CSP plants, whose goal is to reduce the levelized cost of electricity (LCOE) to 0.05 $/kWh. This paper presents a techno-economic analysis to study if a CSP system with free-falling particle receiver can achieve this goal. The plant analyzed integrates two ground-based bins to store the excess energy and a supercritical CO2 cycle to generate electricity. The model used for the analysis presents several upgrades to previous particle systems models in order to increase its fidelity, accuracy, and representativeness of an actual system. The main upgrades are the addition of off-design conditions during the annual simulations in all the components and an improved receiver model validated against CFD simulations. The size of the main components is optimized to obtain the system configuration with minimum LCOE. The results show that particle CSP systems can reduce the LCOE to 0.056 $/kWh if the configuration is composed of 1.61 × 106 m2 of heliostats, a 250 m high tower with a 537 m2 falling particle curtain, and 16 h thermal energy storage.

show abstract

“…This line separates liquid and gas behaviors both below and above the critical pressure. The discontinuity line is defined as the line that consists of points with maximum value of fP for each pressure, where fP is defined in Equation 3.1 [16,31].…”

Section: Best Conditions For Multi-heating Cyclesmentioning

confidence: 99%

Thermodynamic analysis of multi-heating cycles working around the critical point

González-Portillo

Muñoz-Antón

Martínez-Val

2020

Applied Thermal Engineering

View full text Add to dashboard Cite

A new concept in thermal engineering optimization : the pericritical cycle with multi-heating and its application to concentrating solar power

Abstract: 'Proceso cíclico termodinámico sin condensación del fluido con prescripciones acotadas sobre sus puntos de mínima y máxima entalpía y dispositivo para su realización', ES2652522B2.

Cited by 3 publications

References 57 publications

Supercritical CO2 Mixtures for Advanced Brayton Power Cycles in Line-Focusing Solar Power Plants

Supercritical CO2 Mixtures for Advanced Brayton Power Cycles in Line-Focusing Solar Power Plants

Techno-Economic Optimization of CSP Plants with Free-Falling Particle Receivers

Thermodynamic analysis of multi-heating cycles working around the critical point

Contact Info

Product

Resources

About