scholarly journals Department of Energy SBIR Phase I Final Report Novel Lightweight, Low-Cost Heliostat for Concentrating Solar Power

2020 ◽  
Author(s):  
Linden Bolisay ◽  
2020 ◽  
Vol 12 (15) ◽  
pp. 6223
Author(s):  
Emmanuel Wendsongre Ramde ◽  
Eric Tutu Tchao ◽  
Yesuenyeagbe Atsu Kwabla Fiagbe ◽  
Jerry John Kponyo ◽  
Asakipaam Simon Atuah

Electricity is one of the most crucial resources that drives any given nation’s growth and development. The latest Sustainable Development Goals report indicates Africa still has a high deficit in electricity generation. Concentrating solar power seems to be a potential option to fill the deficit. That is because most of the components of concentrating solar power plants are readily available on the African market at affordable prices, and there are qualified local persons to build the plants. Pilot micro-concentrating solar power plants have been implemented in Sub-Saharan Africa and have shown promising results that could be expanded and leveraged for large-scale electricity generation. An assessment of a pilot concentrating solar power plant in the sub-region noticed one noteworthy obstacle that is the failure of the tracking system to reduce the operating energy cost of running the tracking control system and improve the multifaceted heliostat focusing behavior. This paper highlights the energy situation and the current development in concentrating solar power technology research in Africa. The paper also presents a comprehensive review of the state-of-the-art solar tracking systems for central receiver systems to illustrate the current direction of research regarding the design of low-cost tracking systems in terms of computational complexity, energy consumption, and heliostat alignment accuracy.


Author(s):  
Craig S. Turchi ◽  
Zhiwen Ma ◽  
Ty Neises ◽  
Michael Wagner

In 2011, the U.S. Department of Energy (DOE) initiated a “SunShot Concentrating Solar Power R&D” program to develop technologies that have the potential for much higher efficiency, lower cost, and/or more reliable performance than existing CSP systems. The DOE seeks to develop highly disruptive Concentrating Solar Power (CSP) technologies that will meet 6¢/kWh cost targets by the end of the decade, and a high-efficiency, low-cost thermal power cycle is one of the important components to achieve the goal. Supercritical CO2 (s-CO2) operated in a closed-loop Brayton cycle offers the potential of equivalent or higher cycle efficiency versus superheated or supercritical steam cycles at temperatures relevant for CSP applications. Brayton-cycle systems using s-CO2 have a smaller weight and volume, lower thermal mass, and less complex power blocks versus Rankine cycles due to the higher density of the fluid and simpler cycle design. The simpler machinery and compact size of the s-CO2 process may also reduce the installation, maintenance and operation cost of the system.


Author(s):  
Andrea Ambrosini ◽  
Timothy N. Lambert ◽  
Marlene Bencomo ◽  
Aaron Hall ◽  
Kent vanEvery ◽  
...  

Concentrating solar power (CSP) systems use solar absorbers to convert the heat from sunlight to electric power. Increased operating temperatures are necessary to lower the cost of solar-generated electricity by improving efficiencies and reducing thermal energy storage costs. Durable new materials are needed to cope with operating temperatures < 600°C. The current coating technology (Pyromark High Temperature paint) has a solar absorptance in excess of 0.95 but a thermal emittance greater than 0.8, which results in large thermal losses at high temperatures. In addition, because solar receivers operate in air, these coatings have long term stability issues that add to the operating costs of CSP facilities. Ideal absorbers must have high solar absorptance (>0.95) and low thermal emittance (<0.3 at receiver surface operating temperatures), be stable in air, and be low-cost and readily manufacturable. Recent efforts at Sandia National Laboratories have begun to address the issue of more efficient solar selective coatings for tower applications. This paper will present an overview of these efforts which address the development of new coatings on several fronts.


2013 ◽  
Vol 135 (4) ◽  
Author(s):  
Craig S. Turchi ◽  
Zhiwen Ma ◽  
Ty W. Neises ◽  
Michael J. Wagner

Supercritical CO2 (s-CO2) operated in a closed-loop Brayton cycle offers the potential of higher cycle efficiency versus superheated or supercritical steam cycles at temperatures relevant for concentrating solar power (CSP) applications. Brayton-cycle systems using s-CO2 have a smaller weight and volume, lower thermal mass, and less complex power blocks versus Rankine cycles due to the higher density of the fluid and simpler cycle design. The simpler machinery and compact size of the s-CO2 process may also reduce the installation, maintenance, and operation cost of the system. In this work we explore s-CO2 Brayton cycle configurations that have attributes that are desirable from the perspective of a CSP application, such as the ability to accommodate dry cooling and achieve greater than 50% efficiency, as specified for the U.S. Department of Energy SunShot goal. Recompression cycles combined with intercooling and/or turbine reheat appear able to hit this efficiency target, even when combined with dry cooling. In addition, the intercooled cycles expand the temperature differential across the primary heat exchanger, which is favorable for CSP systems featuring sensible-heat thermal energy storage.


Author(s):  
Brandon T. Gorman ◽  
Nathan G. Johnson ◽  
James E. Miller ◽  
Ellen B. Stechel

Concentrating solar power systems coupled to energy storage schemes, e.g. storage of sensible energy in a heat transfer fluid, are attractive options to reduce the transient effects of clouding on solar power output and to provide power after sunset and before sunrise. Common heat transfer fluids used to capture heat in a solar receiver include steam, oil, molten salt, and air. These high temperature fluids can be stored so that electric power can be produced on demand, limited primarily by the size of the capacity and the energy density of the storage mechanism. Phase changing fluids can increase the amount of stored energy relative to non-phase changing fluids due to the heat of vaporization or the heat of fusion. Reversible chemical reactions can also store heat; an endothermic reaction captures the heat, the chemical products are stored, and an exothermic reaction later releases the heat and returns the chemical compound to its initial state. Ongoing research is investigating the scientific and commercial potential of such reaction cycles with, for example, reduction (endothermic) and re-oxidation (exothermic) of metal oxide particles. This study includes thermodynamic analyses and considerations for component sizing of concentrating solar power towers with redox active metal oxide based thermochemical storage to reach target electrical output capacities of 0.1 MW to 100 MW. System-wide analyses here use one-dimensional energy and mass balances for the solar field, solar receiver reduction reactor, hot reduced particle storage, re-oxidizer reactor, power block, cold particle storage, and other components pertinent to the design. This work is part of a US Department of Energy (DOE) SunShot project entitled High Performance Reduction Oxidation of Metal Oxides for Thermochemical Energy Storage (PROMOTES).


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