Thermo-electric Energy Storage Research Articles

Integrated Thermoelectric Energy Storage in A Combined Cycle Solar Power Plant (tour)

Multi megawatt-thermoelectric energy storage based on thermodynamic cycles is an ambitious solution for the renewable energies conversion. The main advantage of this technology is the capacity of energy storage, However, ensuring the operation of TEES stations during unfavorable weather conditions is suspended. In this article, a specific thermoelectric energy storage system was studied «TEES», the TEES system converts electrical energy into sensible heat by means of an electric heater that uses the joule heating effect, the system TEES converts sensible heat into electrical energy by means of a hybrid power plant that operates on a combined cycle « Brayton and Rankine ». The hybrid power plant uses two thermal energy sources In order to secure the station in unfavorable weather conditions for the production of solar energy. The main idea is to using the gaz and the sensible heat stored as two thermal inputs in the gas turbine that uses a Brayton cycle, the thermal rejection from the gas turbine was recovered and used as a thermal input in the conventional steam turbine plant that uses a Rankine cycle. A thermodynamic analysis of the TEES system was performed in steady state, using the thermodynamic properties of the Coolprop database, a maximum thermal efficiency or Round trip electrical efficiency of 50% has been reached; when the heating temperature of the compressed air reaches 1100 ° C and When the isentropic efficiency of steam turbine is 90 percent.

Electrothermal transport of water conveying copper, silver and alumina nanoparticles through a vertical wavy microchannel

This study emphasizes the significance of optimizing heat transmission, energy conversion, and thermal management in electronic devices, renewable energy systems, and emerging technologies like thermoelectric devices and energy storage systems. The aim is to enhance heat transfer efficiency for improved performance and lifespan of electronic equipment. The research utilizes a mathematical flow analysis to study a water-based ternary nanofluid’s flow and thermal characteristics in a vertical microfluidic channel driven by peristalsis and electroosmosis. The ternary-hybrid nanofluid (THNF), comprising copper, silver, and alumina nanoparticles dissolved in water, is examined considering induced magnetic fields. The study delves into fluid flow, heat absorption, and mixed convection, using Debye–Hückel, lubrication, and long wavelength approximations. Results show that THNF exhibits superior heat transmission compared to pure water. Increasing solid volume fraction of nanoparticles decreases THNF’s temperature. Induced magnetic fields impact the system. This research could influence thermal pipe heat sinks and bioengineered medical devices design.

Proton-Coupled Electron Transfer Aided Thermoelectric Energy Conversion and Storage.

Low-grade heat is ubiquitous in the environment and its thermoelectric conversion by the ionic conductors remains a challenge because of the low efficiency and poor sustainability. Here we demonstrate that the thermoelectric performances can be boosted by combining the Soret effect of protons and proton-coupled electron transfer (PCET) reaction of benzoquinone and hydroquinone in hydrogels. An overall enhancement of thermopower (25.9 mV K-1), power factor (5 mW m-1 K-2), figure of merit (>2.4) and continuity of power output is achieved. Moreover, an energy-storage function can be achieved by the redox couple, and a retained power output of 27.7%, or 14 mW m-2 for more than 3 hours is obtained by the re-balance of PCET reactants in the hydrogel after the removal of the temperature gradient.

Phonon interference effects in graphene nanomesh

Graphene nanomesh (GNM) is a single-layer graphene material that has a periodic distribution of nanoscale pores. GNM shows great potential applications in various fields such as thermoelectric energy conversion, energy storage, and field-effect transistors. In this study we utilize non-equilibrium molecular dynamics and lattice dynamics method to investigate the thermal transport mechanism of GNM. The thermal conductivity of GNM is mainly affected by the number of nanoscale pores and their horizontal and vertical spacing. Our study finds that as the number of nanoscale pores increases, the thermal conductivity of GNM decreases significantly. Additionally, the increase of the number of nanoscale pores causes phonon branch to be folded and confined, which results in a flatter dispersion curve, wider bandgap, and slower phonon group velocity. Moreover, the horizontal and vertical spacing of the nanoscale pores jointly affect the thermal transport process of GNM. When the horizontal spacing is small, the thermal conductivity of GNM decreases monotonically with the increase of vertical spacing, and increases monotonically with an increase of horizontal spacing. However, as the horizontal spacing increases, the interference effect caused jointly by phonon reflection and superposition leads to significant fluctuations in thermal conductivity. The analysis of the spectral heat flow, density of states, participation rate, and group velocity of GNM indicate that the variation in vertical spacing leads to different phonon contributions to heat flow, resulting in fluctuations in the thermal conductivity of GNM. These findings could serve as a reference for controlling the thermal transport of graphene nanomesh, and are of great significance in regulating the thermal conductivity and designing nanoscale pores in GNM.

Optimization of energy balances of a photovoltaic power plant with electrochemical and thermal storage of solar energy

THE PURPOSE. Exploring the possibility of building hybrid power plants to reduce the shortage and cost of energy in Iraq through the combined use of solar electrochemical and thermal batteries.METHODS. Analytical methods in the field of construction of consumer energy supply systems from photovoltaic plants, methods of computer-mathematical modeling.RESULTS.The analysis of daily algorithms for the operation of a solar thermal energy supply system was carried out using the example of a social facility in Iraq using electrochemical and thermoelectric energy storage systems, taking into account the variation in the level of solar radiation, ambient temperature and energy consumption by seasons. An optimal algorithm for the conditions under study is proposed for the operation of the solar energy supply system and its elements. Methods for building an intelligent thermoelectric controller have been defined, which ensure the conversion of the maximum available energy of the PV power plant into thermal energy.CONCLUSION. It turns out that the proposed structure for the construction of photovoltaic power plants with combined storage of electricity is preferable to consumers with large thermal loads, because of the efficiency of direct conversion of electricity from photovoltaic modules to thermal energy is higher than the efficiency of thermal conversion through an intermediate link - an electrochemical battery. The paper proposes the principle of creating intelligent thermoelectric controllers, which ensure the operation of a photovoltaic power plant in maximum power mode.

Spectroscopy of Filled Single-Walled Carbon Nanotubes.

Many envisaged applications, such as nanoelectronics, photovoltaics, thermoelectric power generation, light-emission devices, energy storage and biomedicine, necessitate single-walled carbon nanotube (SWCNT) samples with specific uniform electronic properties. The precise investigation of the electronic properties of filled SWCNTs on a qualitative and quantitative level is conducted by optical absorption spectroscopy, Raman spectroscopy, photoemission spectroscopy and X-ray absorption spectroscopy. This review is dedicated to the description of the spectroscopic methods for the analysis of the electronic properties of filled SWCNTs. The basic principle and main features of SWCNTs as well as signatures of doping-induced modifications of the spectra of filled SWCNTs are discussed.

Total solar spectrum energy converter with integrated photovoltaics, thermoelectrics, and thermal energy storage: System modeling and design

A total-spectrum-utilizing integrated photovoltaic (PV), thermoelectric (TEG), and thermal energy storage fluid (TES) solar energy converter (PV-TEG-TES) with novel device architecture is proposed, and its performance is modeled to demonstrate its viability and optimize its system-level design. By incorporating a top-layer GaAs PV, ultraviolet and visible light is absorbed and converted directly to electricity, while infrared radiation passes through the PV. This infrared radiation is then captured by the TEG and TES layers to supply additional electricity or to be stored as thermal energy. In addition, the TEG converts to electricity otherwise wasted heat from thermalization of photons within the PV layer, and the TES effectively cools the PV, keeping it within adequate operating temperatures. According to analysis predicting upper bound performance, this PV-TEG-TES device can outperform the electrical conversion efficiency of a single GaAs solar cell module by 1.9 percentage points (from 24.1% for PV alone to 26.0% for the combined device, a relative 7.9% improvement), and can convert and store a total of 79.3% of incident solar energy under a concentration ratio of 673 suns per direct solar spectrum. An analytical framework using a successive overrelaxation technique for solutions to the nonlinearly coupled radiative, thermal, fluid, and electrical phenomena in such a PV-TEG-TES device is also discussed, offering a starting point for practical device parameters.

Integration of energy storage systems based on transcritical CO2: Concept of CO2 based electrothermal energy and geological storage

Energy storage systems are crucial for the massive deployment of renewable energy at a large scale. This paper presents a conceptual large-scale thermoelectrical energy storage system based on a transcritical CO2 cycle. The concept is developed through the analysis of three high-efficiency systems: renewable energy storage using a thermoelectric energy storage system based on a reversible heat pump; a CO2 storage system; and novel integration of energy storage using a reversible heat pump and geological injection of CO2. The latter system efficiently integrates energy and CO2 storage, taking advantage of the synergies between the operational requirements of both systems. The system uses CO2 captured in stationary sources as a working fluid to store energy from renewables. The energy is stored and recovered in geological formation and heat/cold tanks, with energy storage based on sensible or latent heat of ice and water. A fraction of the CO2 is expected to be permanently sequestered in the geological formation. The analysis of the time evolution of the system, under different operation profiles, shows the interest of the concept as a feasible integration for energy storage and CO2 capture based on renewable energy, with an electric-to-electric efficiency varying between 40 and 50 %.

Multifunctional solar bamboo straw: Multiscale 3D membrane for self-sustained solar-thermal water desalination and purification and thermoelectric waste heat recovery and storage

Solar desalination and purification based on interfacial evaporation have great potential to alleviate global water scarcity. However, real-world interfacial evaporation suffers from several issues in clean water collection and solar-to-clean-water energy efficiency. Here, a new concept of multifunctional natural membrane interfacial evaporation (MNMIE) is demonstrated, achieving the whole cycle of energy conversion from solar energy harvesting to waste heat recovery and storage while effectively desalinating and purifying water. The 3D, multiscale membrane derived from sustainable bamboo presents a mean pore size of 150 nm and a porosity of 63.8%, comparable to the commercial membranes. The as-generated vapor from a self-sustained evaporation process is guided to permeate through the porous bamboo node into the bamboo chamber facing unfocused incident light (1 sun) and then condenses, resulting in a high water collection ratio of 81.0% and solar-to-clean water efficiency of 67.4%. Moreover, the waste heat from desalination is recovered through direct thermoelectric energy conversion and storage under unfocused solar light. The fully integrated cycle of energy conversion, storage, and utilization for clean water and electricity generation enabled by the multifunctional natural membrane is scalable, economic and represents a highly promising solution for sustainable energy cycles enabled by nanotechnology-empowered natural resources.

Exergo-Economic and Environmental Analysis of a Solar Integrated Thermo-Electric Storage

Renewable energies are often subject to stochastic resources and daily cycles. Energy storage systems are consequently applied to provide a solution for the mismatch between power production possibility and its utilization period. In this study, a solar integrated thermo-electric energy storage (S-TEES) is analyzed both from an economic and environmental point of view. The analyzed power plant with energy storage includes three main cycles, a supercritical CO2 power cycle, a heat pump and a refrigeration cycle, indirectly connected by sensible heat storages. The hot reservoir is pressurized water at 120/160 °C, while the cold reservoir is a mixture of water and ethylene glycol, maintained at −10/−20 °C. Additionally, the power cycle’s evaporator section rests on a solar-heated intermediate temperature (95/40 °C) heat reservoir. Exergo-economic and exergo-environmental analyses are performed to identify the most critical components of the system and to obtain the levelized cost of electricity (LCOE), as well as the environmental indicators of the system. Both economic and environmental analyses revealed that solar energy converting devices are burdened with the highest impact indicators. According to the results of exergo-economic analysis, it turned out that average annual LCOE of S-TEES can be more than two times higher than the regular electricity prices. However, the true features of the S-TEES system should be only fully assessed if the economic results are balanced with environmental analysis. Life cycle assessment (LCA) revealed that the proposed S-TEES system has about two times lower environmental impact than referential hydrogen storage systems compared in the study.

Thermoelectric Energy Storage Using Auxiliary Solar Thermal and Geothermal Energy

Abstract Multi-megawatt thermoelectric energy storage (TEES) based on thermodynamic cycles is a promising alternative to pumped-storage hydroelectricity (PSH) and compressed air energy storage (CAES) systems. The size and cost of energy storage are the main advantages of this technology as it generally uses inexpensive energy storage materials and does not require high-pressure tanks or rare geographic terrain, but the round trip electric efficiency of this technology remains low compared to its competitors. In this context, the objective of this article is to study and simulate a TEES system. A TEES system converts electrical energy to thermal energy by means of an electric heater uses joule heating effect, the system storage this thermal energy in solar salt. Stored thermal energy is converted into electrical energy by a thermal engine uses the organic Rankine cycle (ORC). An auxiliary energy source is integrated with the organic Rankine cycle to improve the round trip electric efficiency of the system. Auxiliary energy source can be solar thermal and geothermal at an average temperature between 100 and 140 °C, which is used to evaporate the working fluid to saturation. The steam is then superheated by stored thermal energy. The superheated steam expands in a turbine producing a good amount of energy compared to the saturated steam expansion. Methanol (CH3OH) has been used as a working fluid because its boiling point is less than 100 °C at the atmospheric pressure.

Mutual Insight on Ferroelectrics and Hybrid Halide Perovskites: A Platform for Future Multifunctional Energy Conversion.

An insight into the analogies, state-of-the-art technologies, concepts, and prospects under the umbrella of perovskite materials (both inorganic-organic hybrid halide perovskites and ferroelectric perovskites) for future multifunctional energy conversion and storage devices is provided. Often, these are considered entirely different branches of research; however, considering them simultaneously and holistically can provide several new opportunities. Recent advancements have highlighted the potential of hybrid perovskites for high-efficiency solar cells. The intrinsic polar properties of these materials, including the potential for ferroelectricity, provide additional possibilities for simultaneously exploiting several energy conversion mechanisms such as the piezoelectric, pyroelectric, and thermoelectric effect and electrical energy storage. The presence of these phenomena can support the performance of perovskite solar cells. The energy conversion using these effects (piezo-, pyro-, and thermoelectric effect) can also be enhanced by a change in the light intensity. Thus, there lies a range of possibilities for tuning the structural, electronic, optical, and magnetic properties of perovskites to simultaneously harvest energy using more than one mechanism to realize an improved efficiency. This requires a basic understanding of concepts, mechanisms, corresponding material properties, and the underlying physics involved with these effects.

Thermoelectric energy storage with geothermal heat integration – Exergy and exergo-economic analysis

The proposed Thermo-Electric Energy Storage (TEES) system addresses the need for peak-load support (1–2 daily hours of operation) for small-distributed users who are often owners of small/medium size PV systems (4 to 50 kWe) and wish to introduce a reliable storage system able to compensate the productivity/load mismatch. The proposed thermoelectric system relies on sensible heat storage: a warm resource at 120/160 °C (a hot water reservoir system), and a cold resource at −10 /−20 °C (a cold reservoir system containing water and ethylene glycol). The power cycle operates through a trans-critical CO2 scheme including recuperation; in the storage mode, a supercritical heat pump restores heat to the hot reservoir, while a cooling cycle (using a suitable refrigerant) cools the cold reservoir. The power cycle and the heat pump benefit from geothermal heat integration at low-medium temperatures (80–120 °C), thereby allowing to achieve a marginal round-trip efficiency (electric-to-electric) in the range from 50 to 75% (not considering geothermal heat integration).The three systems are analyzed with different resource conditions and parameters setting (hot storage temperature, pressure levels for all cycles, ambient temperature…); exergy and exergo-economic analyses are performed to evaluate the economic competitiveness and in order to identify the critical items in the system. A sensitivity analysis on the main parameters affecting the produced power cost of the system per unit electric energy is carried out.

Thermally chargeable supercapacitor using a conjugated conducting polymer: Insight into the mechanism of charge-discharge cycle

Ubiquitous temperature-difference thermally energy, which is typically ignored without use, can be extremely valuable for mobile energy storage devices in environments with large temperature differences. A valuable choice for this low-grade thermally energy recovery has been thermoelectric energy storage or conversion, but small output energy storage necessitates sensitive supercapacitor component such as a suitable electrode material and electrolyte. In this work, a novel conjugated all-conducting polymer is synthesized, namely PDAQ-BC via Buchwald-Hartwig coupling method between 2,6-diaminoanthraquinone (DAQ) and 3,6-dibromo-9-(4-bromophenyl)carbazole (DBC). The PDAQ-BC exhibits specific capacitance of 180.5 F g−1 at a current of 1 A g−1 retaining 84% capacitances and about 95% coulombic efficiency upon 5000 cycles at a current density of 5 A g−1. Furthermore, a thermally chargeable supercapacitor (TCS) assembled by PDAQ-BC electrode and polystyrene sulfonic acid film (PSSH) solid electrolyte, which shows a greatly output potential of 6.67 mV K−1 and stable potential retention over 30 h. With a small temperature gradient of 10.8 and 5.2 °C, the TCS produce 72 and 43 mV, respectively. More interestingly, the output potential of TCS is related to temperature gradient and PDAQ-BC electrode, but not to the thickness of the PSSH electrolyte.

Exergetic and economic assessment of integrated cryogenic energy storage systems

Cryogenics-based Energy Storage (CES) is a thermo-electric bulk energy storage technology that received much attention lately both in academia and industrial applications. CES charges surplus electricity in an energy-intense gas liquefaction process, stores electricity in form of liquid air and discharges electricity in a liquid-air Rankine cycle.CES is associated with a number of advantages towards competing bulk-energy storage technologies. CES is based on mature technologies, having a low environmental impact, no geographical constraints, long cycle life, low standby losses and a remarkable exergy density. At present, CES is at a pre-commercial state, which makes its claimed competitive specific costs and reported stand-alone efficiency of 40–60% crucial to its further development and application. This paper aims to identify the efficiencies and specific costs of a number of CES system configurations and to investigate the sensitivity of estimating CES costs to the wide range of reported characteristics. The exergetic and economic analyses are based on results from simulation of seven system configurations in ASPEN Plus®. Economic sensitivity analysis is conducted independently and relies solely on data from literature. Among others, the effects of the following parameters on the CES levelized cost of discharged electricity are evaluated: price of electricity, specific investment cost, annual operation hours and economic life.The exergetic analysis revealed the favourable integration of regasifying LNG, in which the CES exergetic efficiency reaches 55%. Integration of waste heat was shown to reduce the specific costs of 300 MW CES systems from 1400 €/kWh to 1100 €/kWh. Lowest levelized cost of electricity was reached by diabatic CES systems with combustion of natural gas (161 €/MWh) closely followed by waste heat integration (171 €/MWh). In the sensitivity analysis the effects of the specific costs and the cost of charged electricity were found to be of greater importance than efficiency. Moreover, CES was evaluated to be economically feasible in comparison to other bulk energy storage technologies.

Thermo-Electric Energy Storage with Solar Heat Integration: Exergy and Exergo-Economic Analysis

A Thermo-Electric Energy Storage (TEES) system is proposed to provide peak-load support (1–2 daily hours of operation) for distributed users using small/medium-size photovoltaic systems (4 to 50 kWe). The purpose is to complement the PV with a reliable storage system that cancompensate the produc tivity/load mismatch, aiming at off-grid operation. The proposed TEES applies sensible heat storage, using insulated warm-water reservoirs at 120/160 °C, and cold storage at −10/−20 °C (water and ethylene glycol). The power cycle is a trans-critical CO2 unit including recuperation; in the storage mode, a supercritical heat pump restores heat to the hot reservoir, while a cooling cycle cools the cold reservoir; both the heat pump and cooling cycle operate on photovoltaic (PV) energy, and benefit from solar heat integration at low–medium temperatures (80–120 °C). This allows the achievement of a marginal round-trip efficiency (electric-to-electric) in the range of 50% (not considering solar heat integration).The TEES system is analysed with different resource conditions and parameters settings (hot storage temperature, pressure levels for all cycles, ambient temperature, etc.), making reference to standard days of each month of the year; exergy and exergo-economic analyses are performed to identify the critical items in the complete system and the cost of stored electricity.

Solar thermal conversion and thermal energy storage of CuO/Paraffin phase change composites

A nanofluid phase change material (PCM) is prepared by adding a small amount of CuO nanopowders to paraffin, for use in solar thermal conversion, thermal storage, and thermoelectric applications. Results show that adding CuO nanopowders to paraffin can greatly improve the solar thermal conversion capacity by enhancing the light absorption ability of PCMs. The steady temperature increased with increasing mass fraction of CuO NPs at low mass concentrations (0–0.1%). The largest increase was about 2.3 times that of the pure paraffin with comparable latent heat. In the solar thermoelectricity experiments, the open-circuit voltage improved (1.35 V) with the CuO/Paraffin composite (fm = 0.1%) under the same conditions, and was almost 1.8 times that of the pure paraffin. More importantly, a unique feature of the CuO/Paraffin composite PCM is the extension of thermal release, which enables the continuation of the voltage output when the solar simulator is switched off. The introduction of a very low mass concentration of CuO nanopowders can endow the composite PCMs with strong solar absorption ability, and contribute to realizing efficient solar thermal and solar thermoelectric energy conversion and storage. This provides a new prospect for solar radiation usage efficiency and direct solar energy conversion and utilization.

Nanoporous carbon foam structures with excellent electronic properties predicted by first-principles studies

Nanoporous carbon foams (CFs), which are formed by the interconnection of graphene stripes and sp3 hybridized carbon junctions, have attracted great attention owing to their potential applications. However, the structural diversity makes it hard to experimentally gain accurate structural information. By performing first-principles calculations, we propose nanoporous CFs, which are based on the sixfold-wing graphene nanoribbons (SWGNRs), and systematically study their stabilities, mechanical properties, and electronic properties. The results show that the new CF networks are chemically, dynamically, and mechanically stable, and the stabilities are enhanced as the pore size is increased. More importantly, the CFs well-inherit the size-dependent electronic properties of GNRs, and overcome the instabilities and edge effects of GNRs. The superior structural, mechanical, and electronic properties make the γ-CFs potential candidates for application in electronic and thermoelectric devices, hydrogen and energy storage, and molecular screening.

Experimental Study of Supercritical CO2 Heat Transfer in a Thermo-Electric Energy Storage Based on Rankine and Heat-Pump Cycles

Multi-megawatt thermo-electric energy storage based on thermodynamic cycles is a promising alternative to PSH (Pumped-Storage Hydroelectricity) and CAES (Compressed Air Energy Storage) systems. The size and cost of the heat storage are the main drawbacks of this technology but using crystalline superficial bedrock as a heat reservoir could be a readily available and cheap solution. SELECO2 research project considers a thermal doublet consisting in a “hot storage” in a bedrock and a cold storage in an ice pool. The complete system includes a heat pump transcritical CO2 cycle as the charging process and a transcritical CO2 cycle of 1 – 10 MWe as the discharging process. Various technical studies are undertaken to assess the performance of such system. Steady-state thermodynamic models have been realized to optimize system efficiency. In addition, unsteady models of geothermal heat exchanger network were developed for the ground heat storage. An experimental device has been designed and built to test the heat-exchange performance and dynamics. The conditions are intended to reproduce real process dynamics at a laboratory scale. The heat exchanger is at 1/10e scale with a 1.6 m height and 40 mm inner diameter. Temperature (40-130°C) and pressure conditions (~8-12MPa) follow the operating conditions of the real process coupled with a granitic bedrock. First results show that energetic and exergetic performances are better if a specific strategy of short charge and discharge cycles is employed rather than longer charge and discharge phases. Moreover experimental results will be used to improve the above-mentioned numerical simulations and to validate CFD simulations.

Cryogenics-based energy storage: Evaluation of cold exergy recovery cycles

Competitive specific costs, remarkable energy density, long cycle life, moderate efficiencies the possibility of using proven technologies, and the absence of geographical/geological restrictions make cryogenic energy storage (CES) systems very promising low-carbon bulk energy storage technologies. CES is a thermo-electric energy storage unit, which uses surplus electricity to liquefy a gas (cryogen), which is subsequently stored at cryogenic temperature. Subsequently, the thermal energy of cryogen is partially regained in a cold exergy recovery cycle. This paper reviews and evaluates concepts of CES systems and reports the results from exergy analysis. Two cold exergy recovery cycles are considered: (a) direct expansion of liquid air, and (b) expansion of liquid air in combination with an ORC. The addition of an indirect Rankine cycle increases the specific power output of the discharge unit by up to 25%. The usage of cold recovery and storage increases the liquid yield to 0.6 and doubles the exergetic efficiency of the overall system configuration. The energy densities of the proposed systems are in the limit of 120–150 kW h/kg. The round-trip efficiency reaches 40%.