Implementation Of Thermal Energy Storage Research Articles

Energy Efficiency of Concrete with Phase Change Materials

Nowadays, our society has the responsibility of reducing the energy consumed in the building sector. A promising technology to achieve this goal is the implementation of thermal energy storage (TES) solutions in buildings envelopes. Phase change materials (PCM) which act as a thermal buffer, take advantage of the melting temperature of the material to change its state, improving building energy efficiency. This work explores and investigates how with a cheap PCM material, such as surf wax, high impact thermal results are obtained. To check and verify this condition, two concrete specimens were prepared with treated PCM aggregate and two without the PCM. The four test cubes were placed in an oven and using thermal sensors, the data about the temperature evolution during the process of heating and cooling was collected for further analysis. The results between the PCM concrete samples and the samples without PCM were compared, verifying the promising performance in terms of energy impact.

Imperative Role of Photovoltaic and Concentrating Solar Power Technologies towards Renewable Energy Generation

The United Nations Development Programme (UNDP) 2030 agenda illustrates the requirement of expanding infrastructure and advancing technology for delivering modern and sustainable energy services for all in developing countries. Moreover, UNDP also set a goal of increasing the renewable energy share in the global energy. Renewable energy resources are eco-friendly and widely available resources from nature for generating energy. Geothermal energy, wind energy, solar energy, tidal energy, and biomass energy are renewable energy sources. Solar energy is one of the renewable energy generation approaches that harvests energy widely from sun radiation. Photovoltaic (PV) and concentrating solar power (CSP) are the primary technologies to capture solar energy. This study presents the significance of utilizing solar energy for electricity generation globally using PV and CSP technologies. Furthermore, the distinct energy capturing and storing mechanisms of PV and CSP technologies are presented in detail. This article presents the significance and implementation of thermal energy storage for storing energy obtained through CSP technology. Finally, the study presents a considerable gap between PV and CSP in terms of development with future trends.

NanoPCM based thermal energy storage system for a residential building

Implementation of thermal energy storage (TES) systems into a building and facilities improves the performance of the heating/cooling system by reducing energy waste. Thermal performance of a TES relies on the thermophysical properties of the thermal storage medium (TSM). In the present study, a novel two-step selection model has been implemented to choose the best TSM to improve TES system performance. Various types of thermal storage media are investigated considering phase change materials combined with nanoparticles. Thermal storage capacity, heat storage rate, and thermal storage efficiency have been considered as the main selection parameters in a hierarchy method. A significant contribution of this work is the development of a modelling methodology which can be used as a material selection process or tool. It enables the selection of the most efficient TES on a case-by-case basis. This TSM selection technique adds new understanding of selection tools, and new modelling capabilities to this field. It works with a variety of building cooling/heating loads, and helps minimize the environmental impact of extracting/releasing heat to the ground in geothermal applications. The TSM includes PCM and various PCMs have been considered with a melting range of 5–11℃. A material database of 90 different nano phase change materials (nanoPCMs) has been generated by considering ten types of TSMs and nine types of nanoparticles. First, a 2D numerical model has been used to investigate the heat transfer characteristics of the TSM filled in a cylindrical enclosure with a height of 5 cm and a diameter of 1.2 cm. Fourteen different nanoPCMs were selected to further study based on their thermal storage capacity, heat storage rate, and improvement coefficient (ξ) and implemented into a second numerical model (3D) to calculate the thermal storage efficiency of the designed underground TES system with a height of 20 m and a diameter of 1.5 m. Finally, a building heating/cooling load has been implemented in the numerical model to evaluate the performance of the final designed system on the ground temperature throughout five years of operation. The ground temperature and its variation have an effect on the performance of the ground source heat pump. After five years of operation simulation of the no-PCM system, the ground temperature has increased by 1.78℃ to 9.78℃. However, by adding PCM and nanoPCM, the average temperature reduced to 8.95℃ and 8.72℃, respectively.

Trends and future perspectives on the integration of phase change materials in heat exchangers

Traditional review papers provide mainly qualitative information, missing to show the volume, trends, and major contributions in a topic. In response to that, this paper asseses both quantitative and qualitative information regarding the implementation of thermal energy storage using phase change materials in heat exchangers. The data were retrieved from the Scopus database using specific queries relevant to the topic. To investigate the state-of-the-art and research gaps, a keywords analysis was carried out highlighting relevant connections among the major keywords. Moreover, a bibliometric analysis was performed to obtain the trends on the number of publications per year, type of document, authors, affiliation, geographical distribution, journals of publication, and subject areas of research. Based on the keywords and bibliometric analyses, this paper highlights the major contributions and research gaps on the topic.

Design and production of a novel encapsulated nano phase change materials to improve thermal efficiency of a quintuple renewable geothermal/hydro/biomass/solar/wind hybrid system

In this article, a novel hybrid renewable energy system (HRES) is designed, introduced, and constructed to supply power, heat, and pure water. The proposed HRES is comprised of ground source heat pump/microalgal culture pond to produce microalgae biomass, parabolic trough collector/Solar still desalination/Photovoltaic panels to supply heat/electricity/water required for encapsulation of n-Octadecane with polymer shell via miniemulsion polymerization and conversion of bio-oil into biodiesel, and wind turbine/Proton exchange membrane to produce hydrogen in the strategic region of the Persian Gulf, Bandar Abbas. In this system, hybrid Nanofluid is used to increase the efficiency of the solar collector system. Moreover, for the first time, a transesterified conversion reactor (TCR) enhanced with thermal energy storage (TES) powered by renewable energies is introduced to yield more biodiesel. The produced Biodiesel along with diesel fuel with a mixture of air and hydrogen combine to form the fuel of diesel-fueled generator. In order to achieve the highest performance and efficiency of the proposed system, each part of the system is optimized based on the most influencing parameters using experimental design techniques. According to the results, the produced nanocapsules with an Encapsulation production efficiency of 67.1% and an average latent heat of 163.1 kJ/kg had enough potential to be used as TES in the TCR system. As the implementation of TES in the designed TCR could increase the biodiesel production by 34.9%. Also, with a power generation of 2.48 kW, the proposed HRES emitted 12% less NOx than the pure diesel.

Optimisation of biomass-fired cogeneration plants using ORC technology

Abstract In this paper, the problem of optimal sizing of biomass-fired ORC combined heat and power (CHP) unit for existing coal-fired district heating (DH) plant is discussed. The study examines the influence of boundary conditions on the optimal design characteristics of the ORC CHP system within heating plant backfitting project. The optimisation task is solved for given site-specific technical, economic, ecological and legal constraints. The proposed methodology for synthesis of new technological structure takes into account long-term operational experience and results of measurements of a given reference plant. Although the methodology is general, the solution presented in the paper is relevant for Polish DH sector. The analysis considers country specific system of financial incentives for renewable energy projects as well as participation in electricity balancing market and European Trading System (ETS). Thermal energy storage is considered as a solution providing flexibility of CHP system operation. Influence of different electricity, biomass, coal and EUA (European Emission Allowance) prices on optimal size and structure of the cogeneration system is examined. The analysis revealed that economic optima are relatively flat and the range of ORC unit size, for which the value of objective function is close to the optimum is quite wide. Although Net Present Value (NPV) and Internal Rate of Return (IRR) suggest slightly different size of the system, the recommended solutions are the ones with relatively long annual time of operation. The optimum size of ORC for a DH system of approximately 30 MW peak heating output is within the range of electric power of 1–2 MW. It was also found that although market prices and support instruments are nowadays different than at the time of commissioning of the reference plant, the size of the ORC unit is still close to the optimal value. Implementation of thermal energy storage (TES) in the form of hot water storage tank moves the optimal rated electric power of the ORC generator slightly towards higher values. On the other hand, only a small improvement of financial performance is gained by implementation of TES. Considerable improvement of economic performance has been reached after anticipated increase paths for electricity and EUA prices were introduced. In this case however, the recommended optimal size of the ORC CHP remained almost the same as in the case of constant prices.

Energy storage systems review and case study in the residential sector

Energy storage is recognized as an increasingly important parameter in the electricity and energy systems, allowing the generation flexibility and therefore the demand side management. It can contribute to optimal use of generation and grid assets, and support emissions reductions in various economic sectors. Energy storage can support the European Union (EU) targets for efficient use of energy by helping to ensure energy security, a well-functioning internal energy market, and successful implementation of more carbon-cutting renewables online. By strengthen the use of energy storage, the EU can decrease its energy imports, improve the efficiency of the energy system, and keep prices low by better integrating variable renewable energy sources. Moreover energy storage can contribute to better use of renewable energy sources in the energy system since it can store energy produced when the conditions for renewable energy are appropriate but demand may be low. In this framework, primary objective of this study is the investigation, the comparative analysis and the evaluation according to specific criteria of the current thermal energy storage systems. Electrical, electrochemical, thermal, mechanical and chemical energy storage technology and systems are extensively presented and categorized in terms of their advantages and disadvantages as well as in terms of their technical and financial characteristics. This paper also presents the implementation of thermal energy storage in the residential sector. More specifically is examining the application of a phase change material storage system into the building’s walls cavity. The study focuses on the contribution of the applied energy storage system to the overall increase of the energy efficiency of the building.

Behaviour of a concrete wall containing micro‐encapsulated PCM after a decade of its construction

Today, our society has the duty of reducing the energy consumed in the building sector. A promising technology to achieve this goal is the implementation of thermal energy storage (TES) solutions in buildings envelope. Lately, much literature dealing with the effect of the inclusion of latent heat storage materials in construction materials to provide higher thermal inertia has appeared, mostly focusing on the evaluation of the thermal properties, density, or porosity of these new materials. However, few of them evaluated the long stability properties of the materials with embedded PCM when included in a building, very much needed since the lifetime of a building is about 50 years. Therefore, in this study, an evaluation of a house‐like cubicle of concrete with micro‐encapsulated PCM after a decade of its construction is carried out. The results are compared to the tests done in 2005 concluding that the thermal performance of this cubicle presented no degradation in the PCM effect.

Evaluation of energy density as performance indicator for thermal energy storage at material and system levels

The increase of the capacity factor of thermal processes which use renewable energies is closely linked to the implementation of thermal energy storage (TES) systems. Currently, TES systems can be classified depending on the technology for storing thermal: sensible heat, latent heat, and sorption and chemical reactions (usually known as thermochemical energy storage). However, there is no standardized procedure for the evaluation of such technologies, and therefore the development of performance indicators which suit the requisites of the final users becomes an important goal. In the present paper, the authors identified the energy density as an important performance indicator for TES, and evaluated it at both material and system levels. This approach is afterwards applied to prototypes covering the three TES technologies: a two-tank molten salts sensible storage system, a shell-and-tube latent heat storage system, and a magnesium oxide and water chemical storage system. The evaluation of the energy density highlighted the difference of its value at the material value, which presents a theoretical maximum, and the results at system level, which considers all the parts required for operating the TES, and thus presents a significantly lower value. Moreover, the proposed approach captured the effect of the complexity and overall size of the system, showing the relevance of this performance indicator for evaluating technologies for applications in which volume is a limiting parameter.

Computational Screening of Hydration Reactions for Thermal Energy Storage: New Materials and Design Rules

The implementation of thermal energy storage (TES) can improve the efficiency of existing industrial processes, and enable new applications that require the uptake/release of heat on-demand. Among the myriad strategies for TES, thermochemical hydration/dehydration reactions are arguably the most promising due to their high energy densities, simplicity, cost effectiveness, and potential for reversibility at moderate temperatures. The present study uses first-principles calculations to identify TES materials that can out-perform known compounds. High-throughput density functional theory calculations were performed on metal halide hydrates and hydroxides mined from the Inorganic Crystal Structure Database. In total, 265 hydration reactions were characterized with respect to their thermodynamic properties, gravimetric and volumetric energy densities, and operating temperatures. Promising reactions were identified for three temperature ranges: low ( 300 °C). Several hig...

Thermal analysis of a Phase Change Material for a Solar Organic Rankine Cycle

Organic Rankine Cycle (ORC) is a promising technology for low temperature power generation, for example for the utilization of medium temperature solar energy. Since heat generated from solar source is variable throughout the day, the implementation of Thermal Energy Storage (TES) systems to guarantee the continuous operation of solar ORCs is a critical task, and Phase Change Materials (PCM) rely on latent heat to store large amounts of energy.In the present study, a thermal analysis of a PCM for a solar ORC is carried out. Three different types of PCMs are analyzed. The energy equation for the PCM is modeled by using the heat capacity method, and it is solved by employing a 1Dexplicit finite difference scheme. The solar source is modeled with a time-variable temperature boundary condition, with experimental data taken from the literature for two different solar collectors. Results are presented in terms of temperature profiles and stored energy. It has been shown that the stored energy depends on the heat source temperature, on the employed PCM and on the boundary conditions. It has been demonstrated that the use of a metal foam can drastically enhance the stored energy due to the higher overall thermal conductivity.

Characteristics of large thermal energy storage systems in Poland

In District Heating Systems (DHS) there are significant fluctuations in demand for heat by consumers during both the heating and the summer seasons. These variations are considered primarily in the 24-hour time horizon. These problems are aggravated further if the DHS is supplied by a CHP plant, because fluctuations in heat demand adversely affect to a significant degree the stable production of electricity at high overall efficiency. Therefore, introducing Thermal Energy Storage (TES) would be highly recommended on these grounds alone. The characteristics of Large (i.e. over 10 000 m 3 ) TES in operation in Poland are presented. Information is given regarding new projects (currently in design or construction) that apply TES technology in DHS in Poland. The paper looks at the methodology used in Poland to select the TES system for a particular DHS, i.e., procedure for calculating capacity of the TES tank and the system to prevent water stored in the tank from absorbing oxygen from atmospheric air. Implementation of TES in DHS is treated as a recommended technology in the Polish District Heating sector. This technology offers great opportunities to improve the operating conditions of DHS, cutting energy production costs and emissions of pollutants to the atmosphere.

Thermal energy storage for solar-powered organic Rankine cycle engines

The feasibility of energy storage is of paramount importance for solar power systems, to the point that it can be the technology enabler. Regarding concentrated solar power (CSP) systems, the implementation of thermal energy storage (TES) is arguably a key advantage over systems based on photovoltaic (PV) technologies. The interest for highly efficient and modular CSP plants of small to medium capacity (5kWE–5MWE) is growing: organic Rankine cycle (ORC) power systems stand out in terms of efficiency, reliability and cost-effectiveness in such power-range. In this paper a thorough investigation on thermal storage systems tailored to high-temperature (≈300°C) ORC power plants is addressed first, stemming from the observation that the direct storage of the ORC working fluid is effective thanks to its favourable thermodynamic properties. The concept of complete flashing cycle (CFC) is then introduced as a mean of achieving an unmatched system layout simplification, while preserving conversion efficiency. This is a new variant of the Rankine cycle, whereby the vapour is produced by throttling the organic working fluid from liquid to saturated vapour conditions. The presentation and discussion of a case study follows: a 100kWE CFC system with direct thermal energy storage, coupled with state-of-the-art parabolic trough collectors. The proposed turbogenerator achieves an estimated 25% efficiency, which corresponds to a value of 18% in design conditions for the complete system. Considering siloxanes as working fluids, the estimated values of storage density are around 10kWeh/mstorage3.