The Integrated Heat Storage Flash Boiler (HSFB): Review, Principles, Design and Testing

2012 ◽  
Author(s):  
Noam Lior ◽  
Albert Girbal-Puig
Keyword(s):  
Pressure Drop ◽  
Heat Storage ◽  
Supply And Demand ◽  
Thermal Power ◽  
Driving Pressure ◽  
Steam Generation ◽  
Flash Evaporation ◽  
Discharge Performance ◽  
Choked Flow ◽  
Steady State Operation

Systems that store heat in a liquid that can generate vapor for various applications by flash evaporation, sometimes known as steam accumulators, are a relatively simple way for integrated heat storage and vapor/steam generation. Applications include buffering of the transient heat supply and demand in conventionally-fuelled boilers, locomotives and steam power generation systems and more recently in solar thermal power. The information available about this type of heat storage was mostly about steady state operation with little attention to the flash evaporation aspects. In this paper we describe the state of the art and a well-instrumented facility for the experimental study of a variant of such systems, the Heat Storage Flash Boiler that includes a 19.28 m3 storage/flash tank, which was developed by us for experimental examination of its storage and discharge performance for temperatures between 65 °C and 120 °C and pressures from 0.5 to 2 bars (50–200 kPa).. The applicability of such a facility as a generator of steam for feeding a turbine or other purposes has been demonstrated. Flashing has been induced at water temperatures between 80 °C and 100 °C. At 97 °C, the average flow rates obtained ranged between 14 kg/hr for a driving pressure drop of Δpf = 3.2 cm Hg (4.266 kPa), and 390 kg/hr for Δpf = 5.1 cm Hg (6.799 kPa). Specific attention was paid to key issues including the flash evaporation phenomenon, conditions for choked flow of the steam and for mist entrainment, and need and ways for the storage water deaeration. Detailed results for the experimental runs, and the mass flow generation rate of water evaporated was well-correlated to the driving pressure drop for flashing, Δpf. The experiments have provided useful information about the associated heat storage issues and flash steam generation phenomena. Basic considerations and methods for the design of integrated thermal storage/steam generation systems, the Heat Storage Flash Boilers are presented.

Comparison of Two Linear Collectors in Solar Thermal Plants: Parabolic Trough vs Fresnel

2011 ◽  
Author(s):  
A. Giostri ◽  
M. Binotti ◽  
P. Silva ◽  
E. Macchi ◽  
G. Manzolini
Keyword(s):  
Power Plants ◽  
Thermal Power ◽  
Solar Thermal ◽  
Heat Transfer Fluid ◽  
Steam Generation ◽  
Parabolic Trough ◽  
Research Activity ◽  
Optical Efficiency ◽  
Synthetic Oil ◽  
Yearly Average

Parabolic trough can be considered the state of the art for solar thermal power plants thanks to the almost 30 years experience gained in SEGS and, recently, Nevada Solar One plants in US and Andasol plants in Spain. One of the major issues that limits the wide diffusion of this technology is the high investment cost of the solar field and, particularly, of the solar collector. For this reason, since several years research activity has been trying to develop new solutions with the aim of cost reduction. This work compares commercial Fresnel technology with conventional parabolic trough plant based on synthetic oil as heat transfer fluid at nominal conditions and evaluates yearly average performances. In both technologies, no thermal storage system is considered. In addition, for Fresnel, a Direct Steam Generation (DSG) case is investigated. Performances are calculated by a commercial code, Thermoflex®, with dedicated component to evaluate solar plant. Results will show that, at nominal conditions, Fresnel technology have an optical efficiency of 67% which is lower than 75% of parabolic trough. Calculated net electric efficiency is about 19.25%, while parabolic trough technology achieves 23.6%. In off-design conditions, the gap between Fresnel and parabolic trough increases because the former is significantly affected by high radiation incident angles. The calculated sun-to-electric annual average efficiency for Fresnel plant is 10.2%, consequence of the average optical efficiency of 38.8%, while parabolic trough achieve an overall efficiency of 16%, with an optical one of 52.7%. An additional case with Fresnel collector and synthetic oil outlines differences among investigated cases. Finally, because part of performance difference between PT and Fresnel is simple due to different definitions, additional indexes are introduced in order to make a consistent comparison.

Methodology for optimized operation strategies of solar thermal power plants with integrated heat storage

Solar Energy ◽  
2011 ◽  
Vol 85 (4) ◽  
pp. 653-659 ◽  
Author(s):  
Michael Wittmann ◽  
Markus Eck ◽  
Robert Pitz-Paal ◽  
Hans Müller-Steinhagen
Keyword(s):  
Power Plants ◽  
Heat Storage ◽  
Thermal Power ◽  
Solar Thermal ◽  
Thermal Power Plants ◽  
Solar Thermal Power

scholarly journals Modelling and control of solar thermal power generation network in smart grid

2021 ◽  
Vol 25 (4 Part B) ◽  
pp. 2861-2870
Author(s):  
Ruilian Wang ◽  
Zichao Zhang ◽  
Xinxu Wei
Keyword(s):  
Power Generation ◽  
Dynamic Response ◽  
Pid Control ◽  
Heat Storage ◽  
Storage System ◽  
Thermal Power ◽  
Solar Thermal ◽  
Proportional Integral ◽  
Solar Thermal Power ◽  
Solar Thermal Power Generation

The thermal storage system is an essential part of the trough solar thermal power generation system. Due to the strong randomness, intermittency, and volatility of solar energy resources, to further improve the system?s overall reliability to meet the needs of variable operating conditions, the paper optimizes the control strategy of the trough solar heat storage system. Taking the molten salt heat storage medium in the oil/salt heat exchanger, the core equipment of the heat storage system, as the critical research object, the article adopts proportional, integral, and differential (PID) control theories. It builds the system in the MATLAB/Simulink simulation environment mathematical model. We use the critical proportionality method to determine many critical parameters in the control system, tune the proportional coefficient, integral time, and other physical quantities in the PID controller, and analyze the proportional control, proportional-integral control, PID controls the respective dynamic response characteristics of these three different control systems. The simulation and comparative analysis results show that: compared with the other two control methods, PID control can effectively weaken the heat storage system oscillation caused by external disturbance, its dynamic response speed is faster, the adjustment time is shorter, and it can meet the requirements of operational stability. The paper adopts PID control, which reduces the control difficulty of the trough solar heat storage system and improves the adaptability to changes in external meteorological resources. The research results have particular guiding significance at the academic and engineering levels.

scholarly journals Thermal demand response model considering user's satisfaction with heat consumption under electrothermal coupling

2021 ◽  
Vol 236 ◽  
pp. 01034
Author(s):  
Wang Zhenyu ◽  
Zhang Jianhua ◽  
Hu Chunlan ◽  
Xu Lanlan ◽  
Han Yongjun
Keyword(s):  
Demand Response ◽  
Supply And Demand ◽  
Thermal Power ◽  
Response Model ◽  
Power Demand ◽  
Time Sharing ◽  
Economic Operation ◽  
New Energy ◽  
Heating Mode ◽  
Demand Side Response

.In recent years, the development of new energy has become a bottleneck. As a high-quality demand side response resource that can be flexibly dispatched, thermal load can be used to promote the consumption and utilization of new energy. Based on the theory of peak valley electricity price and power demand response mechanism, this paper designs a demand response model of thermal price type, which uses time-sharing heat price to guide users to use heat orderly on the heating side. The simulation results show that the reasonable setting of heat price and satisfaction constraints of different heating modes can effectively change the heating mode of the user side and alleviate the contradiction between the supply and demand of thermal power, reduce the heating cost and realize the economic operation of the system.

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