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The Pacific Northwest Laboratory (PNL) has completed three preliminary site-specific feasibility studies that investigated using aquifer thermal energy storage (ATES) to reduce space and process cooling costs. Chilled water stored in an ATES system could be used to meet all or part of the process and/or space cooling loads at the three facilities investigated. The work was sponsored by the US Department of Energy's (DOE) Office of Energy Management. The ultimate goal of DOE's Thermal Energy Storage Program is to successfully transfer ATES technology to industrial and commercial sectors. The primary objective of this study was to identify prospective sites and determine the technical and economic feasibility of implementing chill ATES technology. A secondary objective was to identify site-specific factors promoting or inhibiting the application of chill ATES technology so that other potentially attractive sites could be more easily identified and evaluated. A preliminary investigation of the feasibility of commercializing chill ATES in automotive assembly facilities was completed. The results suggested that automotive assembly facilities was completed. The results suggested that automotive assembly facilities represent a good entry market for chill ATES, if the system is cost-effective. As a result, this study was undertaken to identify and evaluate prospective chillmore » ATES applications in the automotive industry. The balance of the report contains two main sections. Section 2.0 describes the site identification process. Site feasibility is addressed in Section 3.0. Overall study conclusions and recommendations are than presented in Section 4.0.« less

In countries with high heating demand, waste heat from industrial processes should be carefully utilized in buildings. Finland already has an extensive district heating grid and large amounts of combined heat and power generation. However, despite the average climate, there is little use for excess heat in summer. Waste incineration plants need to be running regardless of weather, so long-term storage of heat requires consideration. However, no seasonal energy storage systems are currently in operation in connection with Finnish waste incineration plants. This study used dynamic energy simulation performed with the TRNSYS 17 software to analyze the case of utilizing excess heat from waste incineration to supplement conventional district heating of a new residential area. Seasonal energy storage was utilized through a borehole thermal energy storage (BTES) system. Parametric runs using 36 different storage configurations were performed to find out the cost and performance range of such plans. Annual energy storage efficiencies from 48% to 69% were obtained for the BTES. Waste heat could generate 37–89% of the annual heat demand. Cost estimations of waste heat storage using BTES are not available in the literature. As an important finding in this study, a levelized cost of heat of 10.5–23.5 €/MWh was obtained for various BTES configurations used for incineration waste heat storage. In the three most effective cases, the stored heat reduced annual CO2 emissions of the residential area by 42%, 64% and 86%. Thus, the solution shows great potential for reducing carbon emissions of district heating in grids connected to waste incineration plants.

Buildings consume approximately ¾ of the total electricity generated in the United States, contributing significantly to fossil fuel emissions. Sustainable and renewable energy production can reduce fossil fuel use, but necessitates storage for energy reliability in order to compensate for the intermittency of renewable energy generation. Energy storage is critical for success in developing a sustainable energy grid because it facilitates higher renewable energy penetration by mitigating the gap between energy generation and demand. This review analyzes recent case studies—numerical and field experiments—seen by borehole thermal energy storage (BTES) in space heating and domestic hot water capacities, coupled with solar thermal energy. System design, model development, and working principle(s) are the primary focus of this analysis. A synopsis of the current efforts to effectively model BTES is presented as well. The literature review reveals that: (1) energy storage is most effective when diurnal and seasonal storage are used in conjunction; (2) no established link exists between BTES computational fluid dynamics (CFD) models integrated with whole building energy analysis tools, rather than parameter-fit component models; (3) BTES has less geographical limitations than Aquifer Thermal Energy Storage (ATES) and lower installation cost scale than hot water tanks and (4) BTES is more often used for heating than for cooling applications.

The objective of the Seasonal Thermal Energy Storage (STES) Program is to demonstrate the economic storage and retrieval of thermal energy on a seasonal basis, using heat or cold available from waste sources or other sources during a surplus period to reduce peak period demand, reduce electric utilities peaking problems, and contribute to the establishment of favorable economics for district heating and cooling systems for commercialization of the technology. The initial thrust of the STES Program is toward utilization of ground-water systems (aquifers) for thermal energy storage. The program has the further objective of evaluating other methods of seasonal storage, both from existing literature and by following current work in other countries. The STES Program is divided into an Aquifer Thermal Energy Storage (ATES) Demonstration Task for demonstrating the commercialization potential of aquifer thermal energy storage technology using an integrated system approach to multiple demonstration projects and a parallel Technical Support Task designed to provide support to the overall STES Program, and to reduce technological and institutional barriers to the development of energy storage systems prior to significant investment in demonstration or commercial facilities. During this initial STES program reporting period, program plans were completed, and the Work Breadkdown Structure,more » budget, schedules, and reporting/review procedures were developed. Responsibility was assumed for existing, ongoing STES contracts and projects.« less

De nouvelles avenues pour le stockage de l'énergie thermique (tes) doivent être étudiées en raison du manque de compétitivité des technologies d'énergie solaire concentrée (CSP). Des solutions doivent être trouvées pour remplacer les réservoirs de sel fondu qui ont un impact économique majeur et sont difficiles à entretenir en raison de problèmes de corrosion. En ce sens, le béton représentait un candidat attrayant en prouvant un excellent tes sensible en CSP. Cependant, sa phase principale, en ciment Portland (PC), a des conséquences environnementales importantes. La production de PC est connue pour émettre des niveaux élevés de gaz polluants, en particulier le CO2. On estime qu'il est responsable de 5 % à 7 % des émissions mondiales de CO2, ce qui en fait un contributeur majeur au changement climatique. Ce travail présente des matériaux cimentaires plus verts, fabriqués à partir de ciments alcalins et de ciments hybrides, destinés à être utilisés comme supports tes alternatifs respectueux de l'environnement dans les usines CSP. Une campagne expérimentale est présentée qui montre que ces matériaux éco-efficaces peuvent avoir de meilleures propriétés mécaniques, que le mortier PC ordinaire, lorsqu'ils sont exposés à des températures élevées, en plus, peuvent offrir des améliorations de leurs propriétés thermiques (conductivité thermique ou chaleur spécifique). La deuxième partie du travail est consacrée aux simulations par éléments finis, dans le but de trouver la meilleure configuration, en termes de sélection des matériaux et de géométrie, qui sont plus efficaces que le système tes. Les travaux montrent les avancées suivantes dans la technologie CSP en utilisant des liants alternatifs respectueux de l'environnement : le volume d'installation peut être réduit de 17 % par rapport à un réservoir de sel fondu, tandis que la surface de l'échangeur de chaleur peut être redimensionnée de 29 % par rapport au système de référence utilisant un PC. Ces améliorations permettent des variations plus importantes de l'efficacité opérationnelle et des capacités dynamiques du CSP et représentent des progrès importants vers le développement de technologies CSP plus efficaces et durables. Es necesario investigar nuevas vías para el almacenamiento de energía térmica (tes) debido a la falta de competitividad de las tecnologías de energía solar concentrada (CSP). Se deben encontrar soluciones para reemplazar los tanques de sal fundida que tienen un gran impacto económico y son difíciles de mantener debido a problemas de corrosión. En este sentido, el concreto representó un candidato atractivo al demostrar una excelente tes sensible en CSP. Sin embargo, su fase principal, hecha de cemento Portland (PC), tiene importantes consecuencias ambientales. Se sabe que la producción de PC emite altos niveles de gases contaminantes, en particular CO2. Se estima que es responsable de entre el 5% y el 7% de las emisiones de CO2 del mundo, lo que lo convierte en un importante contribuyente al cambio climático. Este trabajo presenta materiales cementosos más verdes, hechos de cementos alcalinos y cementos híbridos, para ser utilizados como medios alternativos de tes ecológicos en plantas CSP. Se presenta una campaña experimental que muestra que estos materiales ecoeficientes pueden tener mejores propiedades mecánicas, que el mortero PC ordinario, cuando se expone a altas temperaturas, además, puede ofrecer mejoras de sus propiedades térmicas (conductividad térmica o calor específico). La segunda parte del trabajo está dedicada a las simulaciones de elementos finitos, con el objetivo de encontrar la mejor configuración, en términos de selección de materiales y geometría, que sean más eficientes como sistema tes. El trabajo muestra los siguientes avances en la tecnología CSP mediante el uso de aglutinantes alternativos ecológicos: el volumen de instalación se puede reducir en un 17%, en comparación con un tanque de sal fundida, mientras que la superficie del intercambiador de calor se puede redimensionar en un 29%, en comparación con el sistema de referencia que utiliza PC. Estas mejoras permiten variaciones más amplias en la eficiencia operativa y las capacidades dinámicas de la CSP y representan un progreso importante hacia el desarrollo de tecnologías de CSP más eficientes y sostenibles. New avenues for thermal energy storage (TES) need to be investigated due to the lack of competitiveness of concentrated solar power (CSP) technologies. Solutions must be found to replace molten salt tanks which have a major economic impact and are difficult to maintain due to corrosion problems. In this sense, concrete represented an attractive candidate by proving excellent sensible TES in CSP. However, its main phase, made of Portland cement (PC), has significant environmental consequences. The production of PC is known to emit high levels of polluting gases, particularly the CO2. It is estimated to be responsible for between 5% and 7% of the world's CO2 emissions, making it a major contributor to climate change. This work presents greener cementitious materials, made of alkaline cements and hybrids cements, to be used as alternative eco-friendly TES media in CSP plants. An experimental campaign is presented which shows that these eco-efficient materials can have better mechanical properties, than the ordinary PC mortar, when exposed to high temperatures, in addition, can offer improvements of their thermal properties (thermal conductivity or specific heat). Second part of the work is devoted to Finite Element simulations, with the aim to find the best configuration, in terms of selection of materials and geometry, which are more efficient as TES system. The work is showing the following advancements in CSP technology by using alternative eco-friendly binders: the installation volume can be reduced by 17%, compared to a molten salt tank, while the heat exchanger's surface area can be resized by 29%, compared to the reference system using PC. These improvements enable wider variations in CSP operational efficiency and dynamic capabilities and represent important progress towards developing more efficient and sustainable CSP technologies. يجب التحقيق في طرق جديدة لتخزين الطاقة الحرارية (TES) بسبب الافتقار إلى القدرة التنافسية لتقنيات الطاقة الشمسية المركزة (CSP). يجب إيجاد حلول لتحل محل خزانات الملح المنصهر التي لها تأثير اقتصادي كبير ويصعب الحفاظ عليها بسبب مشاكل التآكل. وبهذا المعنى، مثلت الخرسانة مرشحًا جذابًا من خلال إثبات أنها تجربة معقولة ممتازة في مجال الطاقة الشمسية المركزة. ومع ذلك، فإن مرحلته الرئيسية، المصنوعة من أسمنت بورتلاند (PC)، لها عواقب بيئية كبيرة. من المعروف أن إنتاج PC ينبعث منه مستويات عالية من الغازات الملوثة، وخاصة ثاني أكسيد الكربون. ويقدر أنها مسؤولة عن ما بين 5 ٪ و 7 ٪ من انبعاثات ثاني أكسيد الكربون في العالم، مما يجعلها مساهما رئيسيا في تغير المناخ. يقدم هذا العمل مواد أسمنتية أكثر اخضرارًا، مصنوعة من الأسمنت القلوي والأسمنت الهجين، لاستخدامها كوسيط TES بديل صديق للبيئة في محطات الطاقة الشمسية المركزة. يتم تقديم حملة تجريبية توضح أن هذه المواد ذات الكفاءة البيئية يمكن أن يكون لها خصائص ميكانيكية أفضل، من ملاط PC العادي، عند تعرضها لدرجات حرارة عالية، بالإضافة إلى ذلك، يمكن أن تقدم تحسينات في خصائصها الحرارية (الموصلية الحرارية أو الحرارة النوعية). الجزء الثاني من العمل مخصص لمحاكاة العناصر المحدودة، بهدف العثور على أفضل تكوين، من حيث اختيار المواد والهندسة، والتي هي أكثر كفاءة كنظام TES. يُظهر العمل التطورات التالية في تقنية الطاقة الشمسية المركزة باستخدام مواد رابطة بديلة صديقة للبيئة: يمكن تقليل حجم التركيب بنسبة 17 ٪، مقارنة بخزان الملح المنصهر، في حين يمكن تغيير حجم مساحة سطح المبادل الحراري بنسبة 29 ٪، مقارنة بالنظام المرجعي باستخدام الكمبيوتر. تتيح هذه التحسينات اختلافات أوسع في الكفاءة التشغيلية والقدرات الديناميكية للطاقة الشمسية المركزة وتمثل تقدمًا مهمًا نحو تطوير تقنيات أكثر كفاءة واستدامة للطاقة الشمسية المركزة.

Central solar heating plants with seasonal storage (CSHPSS) are among the most promising technologies to save energy in the industrial and residential-commercial building sectors. This work introduces a systematic approach to optimize these systems according to economic and environmental criteria. Our method, which combines the TRNSYS 17 simulation software with life cycle assessment and multi-objective optimization, identifies optimal CSHPSS designs for any climatic condition and heating demand profile considering economic and environmental criteria simultaneously. The capabilities of this approach are illustrated through its application to a case study of a CSHPSS located in Barcelona (Spain), which satisfies a heating demand for a neighborhood of 1120 dwellings. Numerical results show that the CSHPSS plant leads to significant environmental and economic improvements compared to the use of a conventional natural gas heating system. Our tool can guide engineers and architects in the transition towards a more sustainable residential sector.

AbstractRenewable energies can play a very important role in the development of a new energy model contributing effectively towards a more sustainable development in the mid and long term. In this context Central Solar Heating Plants with Seasonal Storage (CSHPSS) are able to provide space heating and Domestic Hot Water (DHW) to residential buildings with high solar fractions (>50%). These systems are already being used in Central and Northern Europe, as well as in Canada, where there is an important experience in district heating systems. Life Cycle Assessment (LCA) is an objective methodology that evaluates the environmental loads associated with a product, process, or activity, identifying and quantifying the use of mass and energy as well as environmental emissions over its life cycle. It provides a comprehensive view of the environmental aspects of a product or process and a more accurate picture of the true environmental trade-offs in product and process selection. In this paper is presented a LCA of a CSHPSS, which should cover the space heating and DHW demand of 500 dwellings of 100 m2, located in Zaragoza, Spain. Environmental burdens through the life cycle of the system are estimated based on relevant emissions to the atmosphere, e.g. greenhouse gases, NOx, SOx, and comprehensive environmental indicators as, for instance, the IMPACT 2002+ and CED (Cumulative Energy Demand). These indicators allow to evaluate the reduction of the environmental load achieved by the CSHPSS analyzed with respect to conventional space heating and DHW systems, as well as to identify the most critical aspects since an environmental perspective.

Seasonal thermal energy storage (STES) technology is a proven solution to resolve the seasonal discrepancy between heating energy generation from renewables and building heating demands. This research focuses on the performance assessment of district heating (DH) systems powered by low-grade energy sources with large-scale, high temperature underground STES technology. A pilot DH system, located in Chifeng, China that integrates a 0.5 million m3 borehole thermal energy storage system, an on-site solar thermal plant and excess heat from a copper plant is presented. The research in this paper adopts a model-based approach using Modelica to analyze the energy performance of the STES for two district heating system configurations. Several performance indicators such as the extraction heat, the injection heat and the storage coefficient are selected to assess the STES system performance. Results show that a lower STES discharge temperature leads to a better energy performance. A sensitivity analysis of the site properties illustrates that the thermal conductivity of soil is the most influential parameter on the STES system performance. The long-term performance of the STES is also discussed and a shorter stabilization time between one and two years could be achieved by discharging the STES at a lower temperature.