Cost and performance analysis of concentrating solar power systems with integrated latent thermal energy storage

Energy ◽  
2014 ◽  
Vol 64 ◽  
pp. 793-810 ◽  
Author(s):  
K. Nithyanandam ◽  
R. Pitchumani
Author(s):  
K. Nithyanandam ◽  
R. Pitchumani

Integrating a thermal energy storage (TES) in a concentrating solar power (CSP) plant allows for continuous operation even during times when solar radiation is not available, thus providing a reliable output to the grid. In the present study, the cost and performance models of an encapsulated phase change material thermocline storage system are integrated with a CSP power tower system model to investigate its dynamic performance. The influence of design parameters of the storage system is studied for different solar multiples of the plant to establish design envelopes that satisfy the U.S. Department of Energy SunShot Initiative requirements, which include a round-trip exergetic efficiency greater than 95% and storage cost less than $15/kWht for a minimum discharge period of 6 hours. From the design windows, optimum designs of the storage system based on minimum LCOE, maximum exergetic efficiency, and maximum capacity factor are reported and compared with the results of two-tank molten salt storage system. Overall, this study presents the first effort to construct a latent thermal energy storage (LTES)-integrated CSP plant model, that can help decision makers in assessing the impact, cost and performance of a latent thermocline energy storage system on power generation from molten salt power tower CSP plant.


2019 ◽  
Vol 9 (11) ◽  
pp. 2340 ◽  
Author(s):  
Shan Gao ◽  
Yiqing Zhang ◽  
Yu Liu

High renewables penetrated power systems would be greatly influenced by the uncertainty of variable renewable energy such as wind power and photovoltaic power. Unlike wind and photovoltaic plant, concentrating solar power with thermal energy storage has similar dispatchable characteristics as conventional thermal unit. Besides, thermal energy storage could support the coordinated operation of concentrating solar power with an electrical heater, which can be employed to convert surplus electricity in the grid into thermal power stored in thermal energy storage for further utilization. In this paper, concentrating solar power is incorporated into a chance-constrained two-stage stochastic unit commitment model. The model considers the energy and reserve services of concentrating solar power and the uncertainty of renewables. The proposed method is employed to assess the role of a concentrating solar power station with thermal energy storage and an electrical heater to provide grid flexibility in high renewables penetrated power systems. Numerical studies are performed on a modified IEEE 24-bus system to validate the viability of the proposed method for the day-ahead stochastic scheduling. The results demonstrate the economic and reliable value of concentrating solar power station to the improvement of unit commitment schedule, to the mitigation of wind uncertainty and photovoltaic uncertainty, and to the reduction of traditional unit reserve requirement. It is concluded that concentrating solar power with thermal energy storage and an electrical heater is effective in promoting the further penetration of renewables.


Author(s):  
Karthik Nithyanandam ◽  
Ranga Pitchumani

Latent thermal energy storage (LTES) system offers high energy storage density and nearly isothermal operation for concentrating solar power generation. However, the low thermal conductivity possessed by the phase change material (PCM) used in LTES system limits the heat transfer rates. Utilizing thermosyphons to charge or discharge a LTES system offers a promising engineering solution to compensate for the low thermal conductivity of the PCM. The present work numerically investigates the enhancement in the thermal performance of charging and discharging process of LTES system by embedding thermosyphons. A transient, computational analysis of the LTES system with embedded thermosyphons is performed for both charging and discharging cycles. The influence of the design configuration of the system and the arrangement of the thermosyphons on the charge and discharge performance of the LTES installed in a concentrating solar power plant (CSP) is analyzed to identify configurations that lead to improved effectiveness.


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