Author: Siddarth Durga
Publisher:
ISBN:
Category :
Languages : en
Pages : 0
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Book Description
Borehole Thermal Energy Storage (BTES) provides an innovative solution to utilize the subterraneous rock formations as a large thermal battery. The surplus thermal energy produced during the low demand periods is stored in the subsurface through shallow geothermal wells, and efficiently extracted throughout the peak demand months to provide space heating. In this study, a high-temperature BTES system is proposed to satisfy the daily winter heating demand of Snee Hall, Cornell University, Ithaca. The BTES is charged with overproduced summer steam (May to October) from Cornell's Combined Heat and Power Plant and is subsequently harnessed (November to April) through an integrated heat pump (HP). To investigate the techno-economic feasibility of the project, a BTES + HP simulation tool was developed on Python 3.8.1 and validated. The tool simulates the 2-D transient heat transfer processes occurring in the rock structures and quantifies the key multi-year performance metrics (exit fluid temperature profile, the amount of energy stored/extracted, round-trip thermal efficiency and the COP of the heat pump) of the system. The technical performance of multiple BTES configurations was analyzed to optimize the BTES dimensions (number of boreholes, borehole spacing, borehole depth) for the site geological properties. The simulations indicate that an octagonal BTES array (90 m depth, 3 m spacing) with a 250 KW HT-heat pump can provide 94% of Snee Hall's winter heating demand (COP-3.85, BTES efficiency-68.7%). The economic analysis reveals that proposed system has an NPV of $647,912 (year 30), IRR of 15%, and a payback period of 9 to 10 years. The system can offset up to 7349.45 MMBTU of natural gas combustion and save 273 MT CO2 emissions annually.
Author: Luisa F. Cabeza
Publisher: Elsevier
ISBN: 1782420967
Category : Technology & Engineering
Languages : en
Pages : 623
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Book Description
Thermal energy storage (TES) technologies store thermal energy (both heat and cold) for later use as required, rather than at the time of production. They are therefore important counterparts to various intermittent renewable energy generation methods and also provide a way of valorising waste process heat and reducing the energy demand of buildings. This book provides an authoritative overview of this key area. Part one reviews sensible heat storage technologies. Part two covers latent and thermochemical heat storage respectively. The final section addresses applications in heating and energy systems. Reviews sensible heat storage technologies, including the use of water, molten salts, concrete and boreholes Describes latent heat storage systems and thermochemical heat storage Includes information on the monitoring and control of thermal energy storage systems, and considers their applications in residential buildings, power plants and industry
Author:
Publisher:
ISBN:
Category :
Languages : en
Pages : 0
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Book Description
Depleted oil/gas reservoirs represent a waste of underground resources and investments of drilling, and also a potential risk to the earth's environment. Geologic thermal energy storage (GeoTES) is proposed as a solution to convert depleted oil/gas reservoirs into long-term seasonal energy storage. GeoTES can be hybridized with other techniques for viable commercial deployment, such as 1) concentrating solar power (CSP) collectors and 2) heat pumps with excess renewable energy. Here, a technology overview is given on the two GeoTES technologies, which includes system overview, techno-economic models, and case study. Both GeoTES technologies show great potential in the economics of individual project deployment and applicability across the US.
Author: Emil Nilsson
Publisher: Linköping University Electronic Press
ISBN: 9179299024
Category :
Languages : en
Pages : 48
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Book Description
Improving industrial energy efficiency is considered an important factor in reducing carbon dioxide emissions and counteract climate change. For many industrial companies in cold climates, heat generated at the site in summer will not be needed to fulfil the site heat demand during this time, and is thus removed to the outdoor air. Although a mismatch between heat generation and heat demand primarily being seasonal, a mismatch may also exist at times in the winter, e.g. during milder winter days or high production hours. If this excess heat instead of being sent to the outdoors was stored for later use when it is needed, purchased energy for the site could be decreased. One way to do this is by the use of a borehole thermal energy storage (BTES) system. A BTES system stores energy directly in the ground by using an array of closely drilled boreholes through which a heat carrier, often water, is circulated. So far, BTES systems used for heating purposes have mainly been used for storage of solar thermal energy. The BTES system has then been part of smaller district solar heating systems to reduce the seasonal mismatch between incoming solar radiation and heat demand, thus increasing system solar fraction. For this application of BTES systems, energy for storage can be controlled by the sizing of the solar collector area. At an industrial site, however, the energy that can be stored will be limited to the excess heat at the site, and the possible presence of several time-varying processes generating heat at different temperatures gives options as to which processes to include in the heat recovery process and how to design the BTES system. Moreover, to determine the available heat for storage at an industrial site, individual measurements of the heat streams to be included are required. Thus, this must be made more site-specific as compared to that of the traditional usage of BTES systems where solar thermal energy is stored, in which case long-time historic solar radiation data to do this is readily accessible for most locations. Furthermore, for performance predictions of industrial BTES systems to be used for both seasonal and short-term storage of energy, models that can treat the short-term effects are needed, as traditional models for predicting BTES performance do not consider this. Although large-scale BTES systems have been around since the 1970’s, little data is to be found in the literature on how design parameters such as borehole spacing and borehole depth affect storage performance, especially for industrial BTES applications. Most studies that can be found with regard to the designing of ground heat exchanger systems are for traditional ground source heat pumps, working at the natural temperature of the ground and being limited to only one or a few boreholes. In this work, the performance of the first and largest industrial BTES system in Sweden was first presented and evaluated with regard to the storage’s first seven years in operation. The BTES system, which has been used for both long- and short-term storage of energy, was then modelled in the IDA ICE 4.8 environment with the aim to model actual storage performance. Finally, the model was used to conduct a parametric study on the BTES system, where e.g. the impact on storage performance from borehole spacing and characteristics of the storage supply flow at heat injection were investigated. From the performance evaluation it could be concluded that lower than estimated quantities and/or quality of the excess heat at the site, resulting in lower storage supply flow temperatures at heat injection, has hindered the storage from reaching temperatures necessary for significant amounts of energy to be extracted. Based on the repeating annual storage behavior seen for the last years of the evaluation period, a long-term annual heat extraction and ratio of energy extracted to energy injected of approximately 400 MWh/year and 20% respectively are likely. For the comparison of predicted and measured storage performance, which considered a period of three years, predicted values for total injected and extracted energy deviated from measured values by less than 1 and 3% respectively, and predicted and measured values for injected and extracted energy followed the same pattern throughout the period. Furthermore, the mean relative difference for the storage temperatures was 4%. A time-step analysis confirmed that the intermittent heat injection and extraction, occurring at intervals down to half a day, had been captured in the three-year validation. This as predictions would become erroneous when the time step exceeded the time at which these changes in storage operation occur. Main findings from the parametric study include that 1) for investigated supply flows at heat injection, a high temperature was more important than a high flow rate in order to achieve high annual heat extractions and that 2) annual heat extraction would rapidly reduce as the borehole spacing was decreased from the one yielding the highest annual heat extraction, whereas the reduction in annual heat extraction was quite slow when the spacing was increased from this point. Another conclusion that came from the performance evaluation and the parametric study, as a consequence of the Emmaboda storage being designed as a high-temperature BTES system, intended working temperatures being 40–55 °C, was that the possibility of designing the BTES system for low working temperatures should be considered in the designing of a BTES system. Lower storage operation temperatures allow for more energy to be injected and in turn for more energy to be extracted and reduces storage heat losses to the surroundings. Ökad energieffektivisering inom industrin anses vara en nyckelkomponent för att minska koldioxidutsläpp och motarbeta klimatförändringar. För många industrier belägna i kallare klimat behövs under sommaren inte all den värme som alstras på anläggningen för att uppnå anläggningens värmebehov, och värmen avlägsnas därför till utomhusluften. Även om ett överskott av värme framförallt existerar under sommaren kan överskottsvärme även uppstå under vintern, till exempel under mildare vinterdagar eller högproduktionstimmar. Om överskottsvärmen istället för att avlägsnas till utomhusluften lagras till senare då den behövs skulle köpt energi till anläggningen kunna minskas. Ett sätt att åstadkomma detta är med hjälp av ett borrhålsvärmelager. Ett borrhålsvärmelager lagrar energi direkt i marken med hjälp av ett flertal närliggande borrhål genom vilka en värmebärare, vanligtvis vatten, cirkuleras. Hittills har borrhålsvärmelager med syfte att leverera värme framförallt använts för lagring av termisk solenergi. Borrhålsvärmelager har då ingått i solvärmesystem för uppvärmning av enstaka bostadskvarter, för att på så vis minska den säsongsbaserade missanpassningen mellan solinstrålning och värmebehov och öka värmesystemets solfraktion. För denna applikation av borrhålsvärmelager kan energimängder för lagring kontrolleras av storleken på solfångarkollektorytan. För industriella borrhålsvärmelagertillämpningar däremot, bestäms energimängder som kan lagras av den tillgängliga överskottsvärmen vid anläggningen. En industri har dessutom vanligtvis ett flertal energianvändande processer, vilka på grund av tidsvarierande drift och olika kvalitet på den alstrade värmen ger upphov till alternativ för vilka processer som bör integreras i värmeåtervinningssystemet och hur själva borrhålsvärmelagret bör utformas. För beräkning av värmemängder tillgängliga för lagring vid en industriell anläggning krävs dessutom mätdata för de individuella värmeströmmar som ska ingå i lagerprocessen, vilket betyder att detta måste genomföras mer fallspecifikt för industriella borrhålsvärmelagertillämpningar än för borrhålsvärmelager för lagring av solenergi, där historisk solinstrålningsdata för beräkning av detta är direkt tillgänglig för de flesta platser. För prediktioner av prestandan av borrhålsvärmelager användandes för både lång- och korttidslagring behövs dessutom modeller som kan hantera effekterna från korttidslagringen, vilket traditionella modeller för borrhålsvärmelagerprediktioner inte gör. Trots att storskaliga borrhålsvärmelager har byggts sedan 1970-talet finns lite data publicerat över hur olika systemparametrar så som borrhålsavstånd och borrhålsdjup påverkar lagerprestandan, särskilt med avseende på industriella borrhålsvärmelagertillämpningar. De flesta studier i litteraturen kopplat till utformning av borrhålsvärmeväxlarsystem avser traditionell bergvärme där värmepumpen arbetar mot marken vid sin naturliga temperatur och enbart ett fåtal borrhål används. I det här arbetet genomfördes först en utvärdering av det första borrhålsvärmelagret för lagring av industriell överskottsvärme i Sverige med avseende på lagrets första sju år i drift. Borrhålsvärmelagret, vilket har använts för både lång- och korttidslagring, modellerades sedan i IDA ICE 4.8 med målet att återskapa lagrets utfall. Slutligen användes den validerade borrhålsvärmelagermodellen för en parameterisering av lagret, där påverkan på inladdad och urladdad energi och borrhålsvärmelagerverkningsgrad från bland annat borrhålsavstånd och temperatur och storlek på flödet till lagret vid laddning studerades. Från uppföljningen av lagrets utfall konstaterades det att lägre än uppskattade mängder överskottsvärme och/eller kvalitet på överskottsvärmen, resulterande i lägre än uppskattade framledningstemperaturer till lagret vid laddning, har hindrat lagret från att nå temperaturer nödvändiga för att väsentliga mängder energi ska kunna hämtas upp från lagret. Baserat på det på årsbasis cykliska beteende noterat för lagret för de sista åren av utvärderingen är rimliga långsiktiga värden för urladdad energi och borrhålsvärmelagerverkningsgrad cirka 400 MWh/år respektive 20%. För jämförelsen mellan predikterad och uppmätt lagerprestanda, vilken avser en period om tre år, avvek predikterade värden för inladdad och urladdad energi från uppmätta värden med mindre än 1% respektive 3%. Värden för predikterad och uppmätt inladdad och urladdad energi följde dessutom varandra väl under de tre åren. Vidare var den genomsnittliga relativa skillnaden för lagertemperaturerna för valideringsperioden 4%. En tidsstegsanalys bekräftade att modellen hade fångat upp effekterna av den intermittenta driften av lagret, inträffande vid intervall ned till halva dygn, då prediktioner blev felaktiga när simuleringstidssteget överskred tiden för vilka ändringar mellan laddning och urladdning av lagret ägt rum. Huvudsakliga resultat från parameterstudien inkluderar att 1) för undersökta flöden till lagret vid laddning var en hög temperatur viktigare än ett stort massflöde för att uppnå en hög årlig urladdning av energi och 2) den mängd energi som på årsbasis kan hämtas upp från lagret sjönk hastigt när borrhålsavståndet minskades från det avstånd som resulterade i att mest energi kunde laddas ur, medan en långsam minskning sågs när borrhålsavståndet ökades från denna punkt. Ytterligare en slutsats kopplat till påverkan på lagerprestanda från ingående systemparametrar är att möjligheter för utformning av ett lågtemperaturlager bör beaktas vid planering av byggande av borrhålsvärmelager. Genom att reducera lagrets arbetstemperatur kan mer energi laddas in i lagret, vilket i sin tur innebär att mer energi kan laddas ur. En lägre arbetstemperatur innebär även lägre värmeförluster från lagret till dess omgivning.
Author: International Renewable Energy Agency (IRENA)
Publisher:
ISBN: 9789292600167
Category :
Languages : en
Pages : 112
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Book Description
District heating and cooling (DHC) combined with renewable energy sources can help meet rising urban energy needs, improve efficiency, reduce emissions and improve local air quality. Although currently dominated by fossil fuels such as coal and gas, DHC systems can be upgraded, or new networks created, to use solid biofuel, solar and geothermal energy technologies. Depending on local conditions, renewable-based DHC brings a range of benefits, including increased energy security, improved health and reduced climate impact.To date, only a few countries have taken advantage of their renewable resource potential for DHC or created policies to promote further uptake. Sweden and Switzerland have started promoting renewable-based district heating,while Denmark - with ambitious decarbonisation policies -already uses high shares. Many cities and regions envisage a growing role for district in their energy plans; some are also looking increasingly at district cooling.As this REmap sector study from the International Renewable Energy Agency (IRENA) shows, renewables could feasibly supply more than one fifth of the energy needed for DHC worldwide. But to drive the transition, policy makers need to fully understand the costs, bene¿ts and actual potential for renewable-based DHC.
Author:
Publisher:
ISBN:
Category :
Languages : en
Pages : 0
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Book Description
Energy storage is increasingly necessary as Variable Renewable Energy (VRE) technologies are deployed. Seasonal energy storage can shift energy generation from the summer to the winter, but these technologies must have extremely large energy capacities and low costs. Geological Thermal energy storage (GeoTES) is proposed as a solution for long-term energy storage. Excess thermal energy can be stored in permeable reservoirs such as aquifers and depleted hydrocarbon reservoirs for several months. In this article, we describe a techno-economic model that has been developed to evaluate GeoTES systems. The models are developed by combining the output of specialist models which enables the performance and cost of both the subsurface and surface systems to be captured. Off-design models are developed so that the performance can be evaluated at each hour of the year. GeoTES can be charged with two different energy sources: (1) concentrating solar thermal and (2) renewable electricity using heat pumps (henceforth known as a "Carnot Battery"). The stored thermal energy can be used to generate electricity and - uniquely - also directly produce heat that can be used by industrial processes. Furthermore, Carnot-Battery-GeoTES can also be used to form a cold storage reservoir. Preliminary results that quantify the technical and economic performance of these two GeoTES systems are presented.
Author: Halime Ö. Paksoy
Publisher: Springer Science & Business Media
ISBN: 1402052901
Category : Technology & Engineering
Languages : en
Pages : 440
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Book Description
Çukurova University, Turkey in collaboration with Ljubljana University, Slovenia and the International Energy Agency Implementing Agreement on Energy Conservation Through Energy Storage (IEA ECES IA) organized a NATO Advanced Study Institute on Thermal Energy Storage for Sustainable Energy Consumption – Fundamentals, Case Studies and Design (NATO ASI TESSEC), in Cesme, Izmir, Turkey in June, 2005. This book contains manuscripts based on the lectures included in the scientific programme of the NATO ASI TESSEC.
Author: Harald Mehling
Publisher: Springer Science & Business Media
ISBN: 354068557X
Category : Science
Languages : en
Pages : 316
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Book Description
The years 2006 and 2007 mark a dramatic change of peoples view regarding c- mate change and energy consumption. The new IPCC report makes clear that - mankind plays a dominant role on climate change due to CO emissions from en- 2 ergy consumption, and that a significant reduction in CO emissions is necessary 2 within decades. At the same time, the supply of fossil energy sources like coal, oil, and natural gas becomes less reliable. In spring 2008, the oil price rose beyond 100 $/barrel for the first time in history. It is commonly accepted today that we have to reduce the use of fossil fuels to cut down the dependency on the supply countries and to reduce CO emissions. The use of renewable energy sources and 2 increased energy efficiency are the main strategies to achieve this goal. In both strategies, heat and cold storage will play an important role. People use energy in different forms, as heat, as mechanical energy, and as light. With the discovery of fire, humankind was the first time able to supply heat and light when needed. About 2000 years ago, the Romans started to use ceramic tiles to store heat in under floor heating systems. Even when the fire was out, the room stayed warm. Since ancient times, people also know how to cool food with ice as cold storage.
Author: Ioan Sarbu
Publisher: Academic Press
ISBN: 0128116633
Category : Technology & Engineering
Languages : en
Pages : 442
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Book Description
Solar Heating and Cooling Systems: Fundamentals, Experiments and Applications provides comprehensive coverage of this modern energy issue from both a scientific and technical level that is based on original research and the synthesis of consistent bibliographic material that meets the increasing need for modernization and greater energy efficiency to significantly reduce CO2 emissions. Ioan Sarbu and Calin Sebarchievici present a comprehensive overview of all major solar energy technologies, along with the fundamentals, experiments, and applications of solar heating and cooling systems. Technical, economic, and energy saving aspects related to design, modeling, and operation of these systems are also explored. This reference includes physical and mathematical concepts developed to make this publication a self-contained and up-to-date source of information for engineers, researchers, and professionals who are interested in the use of solar energy as an alternative energy source. Includes learning aims, chapter summaries, problems and solutions to support the theories presented Puts a specific emphasis on the practical application of the technologies in heating and cooling systems Contains calculating equations for the energy and economic index of solar systems
Author: Kun Sang Lee
Publisher: Springer Science & Business Media
ISBN: 1447142721
Category : Science
Languages : en
Pages : 158
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Book Description
Underground thermal energy storage (UTES) provide us with a flexible tool to combat global warming through conserving energy while utilizing natural renewable energy resources. Primarily, they act as a buffer to balance fluctuations in supply and demand of low temperature thermal energy. Underground Thermal Energy Storage provides an comprehensive introduction to the extensively-used energy storage method. Underground Thermal Energy Storage gives a general overview of UTES from basic concepts and classifications to operation regimes. As well as discussing general procedures for design and construction, thermo-hydro geological modeling of UTES systems is explained. Finally, current real life data and statistics are include to summarize major global developments in UTES over the past decades. The concise style and thorough coverage makes Underground Thermal Energy Storage a solid introduction for students, engineers and geologists alike.
