Analysis of Concentrating Solar Thermal System to Support Thermochemical Energy Storage or Solar Fuel Generation Processes

2019 ◽  
Author(s):  
Patrick Davenport ◽  
Janna Martinek ◽  
Zhiwen Ma
Keyword(s):  
High Temperature ◽  
Energy Storage ◽  
Solar Energy ◽  
Concentration Ratio ◽  
Operating Conditions ◽  
Solar Thermal ◽  
Superior Performance ◽  
Collection System ◽  
Thermochemical Process ◽  
Solar Field

Abstract A Concentrating solar thermal (CST) system integrated with a high-performance solar receiver can provide high-temperature process heat to drive thermochemical energy storage (TCES) or thermochemical fuel production processes with improved equilibrium conversion and fast reaction rates. An advantage of integrating a CST system with a thermochemical process is the ability to store chemical energy in large quantities for continuous downstream operations. However, a challenge in the effective conversion of solar energy to power or fuels is that high-temperature thermochemical process operating conditions require a high solar concentration ratio for efficient operation which imposes design difficulties for solar energy collection. Integration of the solar collection system with a thermochemical process affects the system efficiency and final product cost due to the relatively high solar field cost. Thus, optimization of the collection system provides a significant opportunity to reduce cost of solar thermochemical power or fuel. In this paper, we present a solar field layout strategy and assess the feasibility of a novel planar-cavity receiver to drive thermochemical processes with reaction temperatures in the range of 500–900°C. The complete solar collection system performance is examined and importance of conducting coupled field/receiver analyses is demonstrated by illustrating how improved spillage control by a modified heliostat aiming strategy impacts system radiative losses downstream. The planar-cavity receiver shows improved performance with increasing concentration ratio and superior performance over a flat plate receiver operating under the same prescribed operating conditions.

Sustainable Cooling with Hybrid Concentrated Photovoltaic Thermal (CPVT) System and Hydrogen Energy Storage

2018 ◽  
Vol 1 (2) ◽  
pp. 40-51 ◽  
Author(s):  
Muhammad Burhan ◽  
Muhammad Wakil Shahzad ◽  
Kim Choon Ng
Keyword(s):  
Energy Storage ◽  
Solar Energy ◽  
Optimization Algorithm ◽  
Concentration Ratio ◽  
Cooling System ◽  
Renewable Energy Sources ◽  
Hot Water ◽  
Hydrogen Energy ◽  
Adsorption Chiller ◽  
Back Plate

Standalone power systems have vital importance as energy source for remote area. On the other hand, a significant portion of such power production is used for cooling purposes. In this scenario, renewable energy sources provide sustainable solution, especially solar energy due to its global availability. Concentrated photovoltaic (CPV) system provides highest efficiency photovoltaic technology, which can operate at x1000 concentration ratio. However, such high concentration ratio requires heat dissipation from the cell area to maintain optimum temperature. This paper discusses the size optimization algorithm of sustainable cooling system using CPVT. Based upon the CPV which is operating at x1000 concentration with back plate liquid cooling, the CPVT system size is optimized to drive a hybrid mechanical vapor compression (MVC) chiller and adsorption chiller, by utilizing both electricity and heat obtained from the solar system. The electrolysis based hydrogen is used as primary energy storage system along with the hot water storage tanks. The micro genetic algorithm (micro-GA) based optimization algorithm is developed to find the optimum size of each component of CPVT-Cooling system with uninterrupted power supply and minimum cost, according to the developed operational strategy. The hybrid system is operated with solar energy system efficiency of 71%.

System and component modelling of a low temperature solar thermal energy conversion cycle

2013 ◽  
Vol 24 (4) ◽  
pp. 51-62
Author(s):  
Shadreck M. Situmbeko ◽  
Freddie L. Inambao
Keyword(s):  
Low Temperature ◽  
Solar Energy ◽  
Thermal Energy ◽  
Electrical Power ◽  
Solar Thermal ◽  
Working Fluid ◽  
Small Scale ◽  
Solar Thermal Energy ◽  
Solar Field ◽  
Conversion Technology

Solar thermal energy (STE) technology refers to the conversion of solar energy to readily usable energy forms. The most important component of a STE technology is the collectors; these absorb the shorter wavelength solar energy (400-700nm) and convert it into usable, longer wavelength (about 10 times as long) heat energy. Depending on the quality (temperature and intensity) of the resulting thermal energy, further conversions to other energy forms such as electrical power may follow. Currently some high temperature STE technologies for electricity production have attained technical maturity; technologies such as parabolic dish (commercially available), parabolic trough and power tower are only hindered by unfavourable market factors including high maintenance and operating costs. Low temperature STEs have so far been restricted to water and space heating; however, owing to their lower running costs and almost maintenance free operation, although operating at lower efficiencies, may hold a key to future wider usage of solar energy. Low temperature STE conversion technology typically uses flat plate and low concentrating collectors such as parabolic troughs to harness solar energy for conversion to mechanical and/or electrical energy. These collector systems are relatively cheaper, simpler in construction and easier to operate due to the absence of complex solar tracking equipment. Low temperature STEs operate within temperatures ranges below 300oC. This research work is geared towards developing feasible low temperature STE conversion technology for electrical power generation. Preliminary small-scale concept plants have been designed at 500Wp and 10KWp. Mathematical models of the plant systems have been developed and simulated on the EES (Engineering Equation Solver) platform. Fourteen candidate working fluids and three cycle configurations have been analysed with the models. The analyses included a logic model selector through which an optimal conversion cycle configuration and working fluid mix was established. This was followed by detailed plant component modelling; the detailed component model for the solar field was completed and was based on 2-dimensional segmented thermal network, heat transfer and thermo fluid dynamics analyses. Input data such as solar insolation, ambient temperature and wind speed were obtained from the national meteorology databases. Detailed models of the other cycle components are to follow in next stage of the research. This paper presents findings of the system and solar field component.

Considerations for the Design of Solar-Thermal Chemical Processes

2010 ◽  
Vol 132 (3) ◽  
Author(s):  
Janna Martinek ◽  
Melinda Channel ◽  
Allan Lewandowski ◽  
Alan W. Weimer
Keyword(s):  
Solar Energy ◽  
Water Splitting ◽  
Thermal Reduction ◽  
Absorption Efficiency ◽  
Chemical Processes ◽  
Solar Thermal ◽  
System Efficiency ◽  
Field Efficiency ◽  
Definition Of ◽  
Solar Field

A methodology is presented for the design of solar thermal chemical processes. The solar receiver efficiency for the high temperature step, defined herein as the ratio of the enthalpy change resulting from the process occurring in the receiver to the solar energy input, is limited by the solar energy absorption efficiency. When using this definition of receiver efficiency, both the optimal reactor temperature for a given solar concentration ratio and the solar concentration required to achieve a given temperature and efficiency shift to lower values than those dictated by the Carnot limitation on the system efficiency for the conversion of heat to work. Process and solar field design considerations were investigated for ZnO and NiFe2O4 “ferrite” spinel water splitting cycles with concentration ratios of roughly 2000, 4000, and 8000 suns to assess the implications of using reduced solar concentration. Solar field design and determination of field efficiency were accomplished using ray trace modeling of the optical components. Annual solar efficiency increased while heliostat area decreased with increasing concentration due to shading and blocking effects. The heliostat fields designed using system efficiency for the conversion of heat to work were found to be overdesigned by up to 21% compared with those designed using the receiver efficiency alone. Overall efficiencies of 13–20% were determined for a “ferrite” based water splitting process with thermal reduction conversions in the range of 35–100%.

scholarly journals Material Selection for Latent Heat Based High Temperature Solar Thermal Energy Storage

2015 ◽  
Vol 74 ◽  
pp. 1525-1532 ◽  
Author(s):  
Ramón Gutiérrez ◽  
Héctor García ◽  
Bruno Cardenas ◽  
Noel León
Keyword(s):  
High Temperature ◽  
Energy Storage ◽  
Latent Heat ◽  
Thermal Energy ◽  
Thermal Energy Storage ◽  
Material Selection ◽  
Solar Thermal ◽  
Solar Thermal Energy ◽  
Selection For

System and Component Transport Considerations of Micro-Pin Based Solar Receivers With High Temperature Gaseous Working Fluids

2018 ◽  
Author(s):  
Brian M. Fronk ◽  
Saad A. Jajja
Keyword(s):  
High Temperature ◽  
Distribution System ◽  
Energy System ◽  
Operating Conditions ◽  
Solar Thermal ◽  
System Level ◽  
Working Fluid ◽  
Solar Thermal Energy ◽  
Working Fluids ◽  
Compressor Power

This paper explores the interactions between micro-pin concentrated receiver designs with overall solar thermal energy system performance, with different operating conditions, working fluid, and required materials of construction. A 320 MW thermal plant coupled to a 160 MW electric sCO2 Brayton cycle is considered as the baseline. The circulating fluid enters the receiver at 550°C, and leaves at 720°C. The thermal storage/power block are located 150 m from the receiver at the base of the receiver tower. A resistance network based thermal and hydraulic model is used to predict heat transfer and pressure drop performance of the micro-pin receiver. This output of this model is coupled to a system level model of the pressure loss and compressor power required in the remainder of the high temperature gas loop. Overall performance is investigated for supercritical carbon dioxide and helium as working fluids, at pressures from 7.5 to 25 MPa, and at delivery temperatures of 720°C. The results show that by modifying pin depth and flow lengths, there are design spaces for micro-pin devices that can provide high thermal performance without significantly reducing the overall solar thermal system output at lower operating pressures. Use of lower pressure fluids enables lower cost materials of construction in the piping and distribution system, reducing the cost of electricity.

scholarly journals Tuning the photochemical properties of the fulvalene-tetracarbonyl-diruthenium system

2016 ◽  
Vol 45 (21) ◽  
pp. 8740-8744 ◽  
Author(s):  
Anders Lennartson ◽  
Angelica Lundin ◽  
Karl Börjesson ◽  
Victor Gray ◽  
Kasper Moth-Poulsen
Keyword(s):  
Energy Storage ◽  
Solar Energy ◽  
Thermal Energy ◽  
Thermal Energy Storage ◽  
Chemical Energy ◽  
Solar Thermal ◽  
Solar Thermal Energy ◽  
System P ◽  
Photochemical Properties

In a Molecular Solar–Thermal Energy Storage (MOST) system, solar energy is converted to chemical energy using a compound that undergoes reversible endothermic photoisomerization.

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