WorldWideScience

Sample records for aquifer thermal energy

  1. Aquifer thermal energy storage program

    Science.gov (United States)

    Fox, K.

    1980-01-01

    The purpose of the Aquifer Thermal Energy Storage Demonstration Program is to stimulate the interest of industry by demonstrating the feasibility of using a geological formation for seasonal thermal energy storage, thereby, reducing crude oil consumption, minimizing thermal pollution, and significantly reducing utility capital investments required to account for peak power requirements. This purpose will be served if several diverse projects can be operated which will demonstrate the technical, economic, environmental, and institutional feasibility of aquifer thermal energy storage systems.

  2. Improving Aquifer Thermal Energy Storage Efficiency

    OpenAIRE

    S. Kranz; G. Blöcher; Ali Saadat

    2015-01-01

    Aquifer thermal energy storage systems play an important role for the future energy supply systems. Such systems can decouple energy availability (e.g. fluctuating renewable energy, waste heat) and energy supply in times of demand. In order to fully contribute to the sustainability of energy supply, the essential requirements of energy storages are high energy efficiency, high reliability, cost effectiveness, as well as operational flexibility. Aquifer Thermal Energy Storage Systems (ATES) me...

  3. Aquifer thermal energy stores in Germany

    International Nuclear Information System (INIS)

    This paper describes the state of essential demonstration projects of heat and cold storage in aquifers in Germany. Into the energy supply system of the buildings of the German Parliament in Berlin, there are integrated both a deep brine-bearing aquifer for the seasonal storage of waste heat from power and heat cogeneration and a shallow-freshwater bearing aquifer for cold storage. In Neubrandenburg, a geothermal heating plant which uses a 1.200 m deep aquifer is being retrofitted into an aquifer heat storage system which can be charged with the waste heat from a gas and steam cogeneration plant. The first centralised solar heating plant including an aquifer thermal energy store in Germany was constructed in Rostock. Solar collectors with a total area of 1000m2 serve for the heating of a complex of buildings with 108 flats. A shallow freshwater-bearing aquifer is used for thermal energy storage. (Authors)

  4. Aquifer thermal energy storage. International symposium: Proceedings

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1995-05-01

    Aquifers have been used to store large quantities of thermal energy to supply process cooling, space cooling, space heating, and ventilation air preheating, and can be used with or without heat pumps. Aquifers are used as energy sinks and sources when supply and demand for energy do not coincide. Aquifer thermal energy storage may be used on a short-term or long-term basis; as the sole source of energy or as a partial storage; at a temperature useful for direct application or needing upgrade. The sources of energy used for aquifer storage are ambient air, usually cold winter air; waste or by-product energy; and renewable energy such as solar. The present technical, financial and environmental status of ATES is promising. Numerous projects are operating and under development in several countries. These projects are listed and results from Canada and elsewhere are used to illustrate the present status of ATES. Technical obstacles have been addressed and have largely been overcome. Cold storage in aquifers can be seen as a standard design option in the near future as it presently is in some countries. The cost-effectiveness of aquifer thermal energy storage is based on the capital cost avoidance of conventional chilling equipment and energy savings. ATES is one of many developments in energy efficient building technology and its success depends on relating it to important building market and environmental trends. This paper attempts to provide guidance for the future implementation of ATES. Individual projects have been processed separately for entry onto the Department of Energy databases.

  5. Biogeochemical aspects of aquifer thermal energy storage.

    NARCIS (Netherlands)

    Brons, H.J.

    1992-01-01

    During the process of aquifer thermal energy storage the in situ temperature of the groundwater- sediment system may fluctuate significantly. As a result the groundwater characteristics can be considerably affected by a variety of chemical, biogeochemical and microbiological reactions. The inter

  6. Aquifer thermal energy (heat and chill) storage

    Energy Technology Data Exchange (ETDEWEB)

    Jenne, E.A. (ed.)

    1992-11-01

    As part of the 1992 Intersociety Conversion Engineering Conference, held in San Diego, California, August 3--7, 1992, the Seasonal Thermal Energy Storage Program coordinated five sessions dealing specifically with aquifer thermal energy storage technologies (ATES). Researchers from Sweden, The Netherlands, Germany, Switzerland, Denmark, Canada, and the United States presented papers on a variety of ATES related topics. With special permission from the Society of Automotive Engineers, host society for the 1992 IECEC, these papers are being republished here as a standalone summary of ATES technology status. Individual papers are indexed separately.

  7. Biogeochemical aspects of aquifer thermal energy storage.

    OpenAIRE

    Brons, H.J.

    1992-01-01

    During the process of aquifer thermal energy storage the in situ temperature of the groundwater- sediment system may fluctuate significantly. As a result the groundwater characteristics can be considerably affected by a variety of chemical, biogeochemical and microbiological reactions. The interplay of these reactions may have a negative influence on the operational performance of ATES-systems. The objective of this thesis was to investigate bacterial clogging processes and the biogeochemical...

  8. Commercialization of aquifer thermal energy storage technology

    Energy Technology Data Exchange (ETDEWEB)

    Hattrup, M.P.; Weijo, R.O.

    1989-09-01

    Pacific Northwest Laboratory (PNL) conducted this study for the US Department of Energy's (DOE) Office of Energy Storage and Distribution. The purpose of the study was to develop and screen a list of potential entry market applications for aquifer thermal energy storage (ATES). Several initial screening criteria were used to identify promising ATES applications. These include the existence of an energy availability/usage mismatch, the existence of many similar applications or commercial sites, the ability to utilize proven technology, the type of location, market characteristics, the size of and access to capital investment, and the number of decision makers involved. The in-depth analysis identified several additional screening criteria to consider in the selection of an entry market application. This analysis revealed that the best initial applications for ATES are those where reliability is acceptable, and relatively high temperatures are allowable. Although chill storage was the primary focus of this study, applications that are good candidates for heat ATES were also of special interest. 11 refs., 3 tabs.

  9. Influence of aquifer heterogeneity on the design and modelling of Aquifer Thermal Energy Storage (ATES) systems

    OpenAIRE

    Bridger, David W.

    2006-01-01

    A modelling study was carried out to evaluate the influence of aquifer heterogeneity, as represented by geologic layering, on heat transport and storage in aquifer thermal energy storage (ATES) systems. An existing ATES system installed within a heterogeneous aquifer system in Agassiz, British Columbia, Canada was used as a case study. Two 3D heat transport models of the study site were developed and calibrated using the heat transport code FEFLOW, including: a "simple" model domain with unif...

  10. Legal and regulatory issues affecting aquifer thermal energy storage

    Energy Technology Data Exchange (ETDEWEB)

    Hendrickson, P.L.

    1981-10-01

    This document updates and expands the report with a similar title issued in October 1980. This document examines a number of legal and regulatory issues that potentially can affect implementation of the aquifer thermal energy storage (ATES) concept. This concept involves the storage of thermal energy in an underground aquifer until a later date when it can be effectively utilized. Either heat energy or chill can be stored. Potential end uses of the energy include district space heating and cooling, industrial process applications, and use in agriculture or aquaculture. Issues are examined in four categories: regulatory requirements, property rights, potential liability, and issues related to heat or chill delivery.

  11. Seasonal thermal energy storage in aquifers. Environmental benefits and risks

    International Nuclear Information System (INIS)

    This symposium informed on the current state of seasonal thermal energy storage in the soil and, especially, in aquifers. Furthermore, the potentially negative impact of such plants on the environment was discussed. Seasonal thermal energy storage is a suitable method in particular in combination with solar energy and for cogeneration power plants. For each technical paper presented a separate subject analysis was carried through. (BWI)

  12. Bioremediation of chlorinated ethenes in aquifer thermal energy storage

    OpenAIRE

    Ni, Z

    2015-01-01

      Subjects: bioremediation; biodegradation; environmental biotechnology, subsurface and groundwater contamination; biological processes; geochemistry; microbiology The combination of enhanced natural attenuation (ENA) of chlorinated volatile organic compounds (CVOCs) and aquifer thermal energy storage (ATES) appears attractive because such integration provides a promising solution for redevelopment of urban areas in terms of improving the local environmental quality as well as achieving ...

  13. Relationship of regional water quality to aquifer thermal energy storage

    International Nuclear Information System (INIS)

    Aquifer thermal energy storage (ATES) involves injection and withdrawal of temperature-conditioned water into and from a permeable water-bearing formation. The groundwater quality and associated geological characteristics were assessed as they may affect the feasibility of ATES system development in any hydrologic region. Seven physical and chemical mechanisms may decrease system efficiency: particulate plugging, chemical precipitation, clay mineral dispersion, piping corrosion, aquifer disaggregation, mineral oxidation, and the proliferation of biota. Factors affecting groundwater quality are pressure, temperature, pH, ion exchange, evaporation/transpiration, and commingling with diverse waters. Modeling with the MINTEQ code showed three potential reactions: precipitation of calcium carbonate at raised temperatures; solution of silica at raised temperature followed by precipitation at reduced temperatures; and oxidation/precipitation of iron compounds. Low concentrations of solutes are generally favorable for ATES. Near-surface waters in high precipitation regions are low in salinity. Groundwater recharged from fresh surface waters also has reduced salinity. Rocks least likely to react with groundwater are siliceous sandstones, regoliths, and metamorphic rocks. On the basis of known aquifer hydrology, ten US water resource regions are candidates for selected exploration and development, all characterized by extensive silica-rich aquifers

  14. Relationship of regional water quality to aquifer thermal energy storage

    Energy Technology Data Exchange (ETDEWEB)

    Allen, R.D.

    1983-11-01

    Ground-water quality and associated geologic characteristics may affect the feasibility of aquifer thermal energy storage (ATES) system development in any hydrologic region. This study sought to determine the relationship between ground-water quality parameters and the regional potential for ATES system development. Information was collected from available literature to identify chemical and physical mechanisms that could adversely affect an ATES system. Appropriate beneficiation techniques to counter these potential geochemical and lithologic problems were also identified through the literature search. Regional hydrology summaries and other sources were used in reviewing aquifers of 19 drainage regions in the US to determine generic geochemical characteristics for analysis. Numerical modeling techniques were used to perform geochemical analyses of water quality from 67 selected aquifers. Candidate water resources regions were then identified for exploration and development of ATES. This study identified six principal mechanisms by which ATES reservoir permeability may be impaired: (1) particulate plugging, (2) chemical precipitation, (3) liquid-solid reactions, (4) formation disaggregation, (5) oxidation reactions, and (6) biological activity. Specific proven countermeasures to reduce or eliminate these effects were found. Of the hydrologic regions reviewed, 10 were identified as having the characteristics necessary for ATES development: (1) Mid-Atlantic, (2) South-Atlantic Gulf, (3) Ohio, (4) Upper Mississippi, (5) Lower Mississippi, (6) Souris-Red-Rainy, (7) Missouri Basin, (8) Arkansas-White-Red, (9) Texas-Gulf, and (10) California.

  15. Initial study of thermal energy storage in unconfined aquifers. [UCATES

    Energy Technology Data Exchange (ETDEWEB)

    Haitjema, H.M.; Strack, O.D.L.

    1986-04-01

    Convective heat transport in unconfined aquifers is modeled in a semi-analytic way. The transient groundwater flow is modeled by superposition of analytic functions, whereby changes in the aquifer storage are represented by a network of triangles, each with a linearly varying sink distribution. This analytic formulation incorporates the nonlinearity of the differential equation for unconfined flow and eliminates numerical dispersion in modeling heat convection. The thermal losses through the aquifer base and vadose zone are modeled rather crudely. Only vertical heat conduction is considered in these boundaries, whereby a linearly varying temperature is assumed at all times. The latter assumption appears reasonable for thin aquifer boundaries. However, assuming such thin aquifer boundaries may lead to an overestimation of the thermal losses when the aquifer base is regarded as infinitely thick in reality. The approach is implemented in the computer program UCATES, which serves as a first step toward the development of a comprehensive screening tool for ATES systems in unconfined aquifers. In its present form, the program is capable of predicting the relative effects of regional flow on the efficiency of ATES systems. However, only after a more realistic heatloss mechanism is incorporated in UCATES will reliable predictions of absolute ATES efficiencies be possible.

  16. Regional assessment of aquifers for thermal-energy storage. Volume 2. Regions 7 through 12

    Energy Technology Data Exchange (ETDEWEB)

    1981-06-01

    This volume contains information on the geologic and hydrologic framework, major aquifers, aquifers which are suitable and unsuitable for annual thermal energy storage (ATES) and the ATES potential of the following regions of the US: Unglaciated Central Region; Glaciated Appalachians, Unglaciated Appalachians; Coastal Plain; Hawaii; and Alaska. (LCL)

  17. A Review on Concepts, Applications, and Models of Aquifer Thermal Energy Storage Systems

    OpenAIRE

    Kun Sang Lee

    2010-01-01

    Being a heat source or sink, aquifers have been used to store large quantities of thermal energy to match cooling and heating supply and demand on both a short-term and long-term basis. The current technical, economic, and environmental status of aquifer thermal energy storage (ATES) is promising. General information on the basic operation principles, design, and construction of ATES systems is discussed in this paper. Numerous projects in operation around the world are summarized to illustra...

  18. THERMAL-ENERGY STORAGE IN A DEEP SANDSTONE AQUIFER IN MINNESOTA: FIELD OBSERVATIONS AND THERMAL ENERGY-TRANSPORT MODELING.

    Science.gov (United States)

    Miller, R.T.

    1986-01-01

    A study of the feasibility of storing heated water in a deep sandstone aquifer in Minnesota is described. The aquifer consists of four hydraulic zones that are areally anisotropic and have average hydraulic conductivities that range from 0. 03 to 1. 2 meters per day. A preliminary axially symmetric, nonisothermal, isotropic, single-phase, radial-flow, thermal-energy-transport model was constructed to investigate the sensitivity of model simulation to various hydraulic and thermal properties of the aquifer. A three-dimensional flow and thermal-energy transport model was constructed to incorporate the areal anisotropy of the aquifer. Analytical solutions of equations describing areally anisotropic groundwater flow around a doublet-well system were used to specify model boundary conditions for simulation of heat injection. The entire heat-injection-testing period of approximately 400 days was simulated. Model-computed temperatures compared favorably with field-recorded temperatures, with differences of no more than plus or minus 8 degree C. For each test cycle, model-computed aquifer thermal efficiency, defined as total heat withdrawn divided by total heat injected, was within plus or minus 2% of the field-calculated values.

  19. Sensitivity analysis of recovery efficiency in high-temperature aquifer thermal energy storage with single well

    DEFF Research Database (Denmark)

    Jeon, Jun-Seo; Lee, Seung-Rae; Pasquinelli, Lisa;

    2015-01-01

    High-temperature aquifer thermal energy storage system usually shows higher performance than other borehole thermal energy storage systems. Although there is a limitation in the widespread use of the HT-ATES system because of several technical problems such as clogging, corrosion, etc., it is get...

  20. Legal and regulatory issues affecting the aquifer thermal energy storage concept

    Energy Technology Data Exchange (ETDEWEB)

    Hendrickson, P.L.

    1980-10-01

    A number of legal and regulatory issus that potentially can affect implementation of the Aquifer Thermal Energy Storage (ATES) concept are examined. This concept involves the storage of thermal energy in an underground aquifer until a later date when it can be effectively utilized. Either heat energy or chill can be stored. Potential end uses of the energy include district space heating and cooling, industrial process applications, and use in agriculture or aquaculture. Issues are examined in four categories: regulatory requirements, property rights, potential liability, and issues related to heat or chill delivery.

  1. Environmental assessment of the potential effects of aquifer thermal energy storage systems on microorganisms in groundwater

    Energy Technology Data Exchange (ETDEWEB)

    Hicks, R.J.; Stewart, D.L.

    1988-03-01

    The primary objective of this study was to evaluate the potential environmental effects (both adverse and beneficials) of aquifer thermal energy storage (ATES) technology pertaining to microbial communities indigenous to subsurface environments (i.e., aquifers) and the propagation, movement, and potential release of pathogenic microorganisms (specifically, Legionella) within ATES systems. Seasonal storage of thermal energy in aquifers shows great promise to reduce peak demand; reduce electric utility load problems; contribute to establishing favorable economics for district heating and cooling systems; and reduce pollution from extraction, refining, and combustion of fossil fuels. However, concerns that the widespread implementation of this technology may have adverse effects on biological systems indigeneous to aquifers, as well as help to propagate and release pathogenic organisms that enter thee environments need to be resolved. 101 refs., 2 tabs.

  2. Field testing of a high-temperature aquifer thermal energy storage system

    Energy Technology Data Exchange (ETDEWEB)

    Sterling, R.L.; Hoyer, M.C. [Univ. of Minnesota, Minneapolis, MN (United States)

    1989-03-01

    The University of Minnesota Aquifer Thermal Energy Storage (ATES) System has been operated as a field test facility for the past six years. Four short-term and two long-term cycles have been completed to data providing a greatly increased understanding of the efficiency and geochemical effects of high-temperature aquifer thermal energy storage. A third long-term cycle is currently being planned to operate the ATES system in conjunction with a real heating load and to further study the geochemical impact on the aquifer from heated waste storage cycles. The most critical activities in the preparation for the next cycle have proved to be the applications for the various permits and variances necessary to conduct the third cycle and the matching of the characteristics of the ATES system during heat recovery with a suitable adjacent building thermal load.

  3. A Review on Concepts, Applications, and Models of Aquifer Thermal Energy Storage Systems

    Directory of Open Access Journals (Sweden)

    Kun Sang Lee

    2010-06-01

    Full Text Available Being a heat source or sink, aquifers have been used to store large quantities of thermal energy to match cooling and heating supply and demand on both a short-term and long-term basis. The current technical, economic, and environmental status of aquifer thermal energy storage (ATES is promising. General information on the basic operation principles, design, and construction of ATES systems is discussed in this paper. Numerous projects in operation around the world are summarized to illustrate the present status of ATES. Hydrogeological-thermal simulation has become an integral part of predicting ATES system performance. Numerical models which are available to simulate an ATES system by modeling mass and heat transport in the aquifer have been summarized. This paper also presents an example of numerical simulation and thermohydraulic evaluation of a two-well, ATES system operating under a continuous flow regime.

  4. Numerical Simulation on the Continuous Operation of Aquifer Thermal Energy Storage System

    OpenAIRE

    Lee, Kun Sang

    2010-01-01

    A mathematical model describing the water flow and convective/conductive thermal energy transport in an ATES system is presented. The three-dimensional thermal process with combined groundwater and heat flow in the aquifer and heat conduction in surrounding layers is solved numerically. This paper presents the results of long-time thermal behavior of ATES system with two wells under continuous operation methods. The effects of various injection-withdrawal rates and durations on computed value...

  5. Framework for ATES [aquifer thermal energy storage] guidelines development. Environmental guideline considerations

    International Nuclear Information System (INIS)

    A study was conducted to assess the environmental impacts of aquifer thermal energy storage (ATES). Rational procedures to assess the impacts of seasonal thermal energy storage on the eco-system have yet to be developed, particularly for aquifer systems. Eight countries (Canada, Denmark, Finland, Germany, the Netherlands, Sweden, Switzerland and the USA) have participated in aquifer thermal energy storage development in a cooperative research and development program under the aegis of the International Energy Agency. Details of research work that has been completed are presented. Benefits of ATES include: less reliance on non-renewable fuels; less environmental degradation; less generation of nuclear fuel waste; greater utilization of available energy; potential for harnessing solar energy; seasonal storage aspects; and decreased potential for groundwater contamination compared to individual heat pump use. Disadvantages include potential geo-thermal reactions and microbiological changes; and increased potential for aquifer contamination from improper design and execution. Rationalizing environmental assessment, rational procedures, water chemistry considerations, well clogging, scaling and corrosion, and microorganisms in ATES sytems are discussed. 52 refs., 10 figs., 3 tabs

  6. Bioremediation of chlorinated ethenes in aquifer thermal energy storage

    NARCIS (Netherlands)

    Ni, Z.

    2015-01-01

      Subjects: bioremediation; biodegradation; environmental biotechnology, subsurface and groundwater contamination; biological processes; geochemistry; microbiology The combination of enhanced natural attenuation (ENA) of chlorinated volatile organic compounds (CVOCs) and aquife

  7. Relative Recovery of Thermal Energy and Fresh Water in Aquifer Storage and Recovery Systems.

    Science.gov (United States)

    Miotliński, K; Dillon, P J

    2015-01-01

    This paper explores the relationship between thermal energy and fresh water recoveries from an aquifer storage recovery (ASR) well in a brackish confined aquifer. It reveals the spatial and temporal distributions of temperature and conservative solutes between injected and recovered water. The evaluation is based on a review of processes affecting heat and solute transport in a homogeneous aquifer. In this simplified analysis, it is assumed that the aquifer is sufficiently anisotropic to inhibit density-affected flow, flow is axisymmetric, and the analysis is limited to a single ASR cycle. Results show that the radial extent of fresh water at the end of injection is greater than that of the temperature change due to the heating or cooling of the geological matrix as well as the interstitial water. While solutes progress only marginally into low permeability aquitards by diffusion, conduction of heat into aquitards above and below is more substantial. Consequently, the heat recovery is less than the solute recovery when the volume of the recovered water is lower than the injection volume. When the full volume of injected water is recovered the temperature mixing ratio divided by the solute mixing ratio for recovered water ranges from 0.95 to 0.6 for ratios of maximum plume radius to aquifer thickness of 0.6 to 4.6. This work is intended to assist conceptual design for dual use of ASR for conjunctive storage of water and thermal energy to maximize the potential benefits. PMID:25399802

  8. Influence of geologic layering on heat transport and storage in an aquifer thermal energy storage system

    Science.gov (United States)

    Bridger, D. W.; Allen, D. M.

    2013-09-01

    A modeling study was carried out to evaluate the influence of aquifer heterogeneity, as represented by geologic layering, on heat transport and storage in an aquifer thermal energy storage (ATES) system in Agassiz, British Columbia, Canada. Two 3D heat transport models were developed and calibrated using the flow and heat transport code FEFLOW including: a "non-layered" model domain with homogeneous hydraulic and thermal properties; and, a "layered" model domain with variable hydraulic and thermal properties assigned to discrete geological units to represent aquifer heterogeneity. The base model (non-layered) shows limited sensitivity for the ranges of all thermal and hydraulic properties expected at the site; the model is most sensitive to vertical anisotropy and hydraulic gradient. Simulated and observed temperatures within the wells reflect a combination of screen placement and layering, with inconsistencies largely explained by the lateral continuity of high permeability layers represented in the model. Simulation of heat injection, storage and recovery show preferential transport along high permeability layers, resulting in longitudinal plume distortion, and overall higher short-term storage efficiencies.

  9. How to achieve optimal and sustainable use of the subsurface for Aquifer Thermal Energy Storage

    International Nuclear Information System (INIS)

    A heat pump combined with Aquifer Thermal Energy Storage (ATES) has high potential in efficiently and sustainably providing thermal energy for space heating and cooling. This makes the subsurface, including its groundwater, of crucial importance for primary energy savings. The regulation of ATES systems is similar in many countries around the world. This paper seeks solutions for the institutional hindrances to the diffusion of ATES. The use of aquifers by individual ATES systems can be optimized to maximize their efficiency on the one hand, and to optimize the performance of the regional subsurface for energy storage on the other. The application of ATES in an aquifer has similar properties as other common resource pool problems. Only with detailed information and feedback about the actual subsurface status, a network of ATES systems can work towards an optimum for both the subsurface and buildings, instead of striving for a local optimum for individual buildings. Future governance of the subsurface may include the self-organization or self-governance. For that the ATES systems need a complementary framework; interpretation of interaction, feedback and adaptable and dynamic control interpretations are the key elements for the optimal and sustainable use of the subsurface. - Highlights: • We show that ATES systems are not using the subsurface optimally and sustainably. • We elaborate how current legislation will not be able to overcome this problem. • We present self-organization as a perspective for governance of ATES systems

  10. Identification and management of potential problems in aquifer thermal energy storage systems

    Energy Technology Data Exchange (ETDEWEB)

    Michel, F.A. [Carleton Univ., Ottawa, ON (Canada); Allen, D.M. [Simon Fraser Univ., Burnaby, BC (Canada)

    2003-07-01

    There is renewed interest in alternative renewable energy sources because of high energy prices, shortages in peak load electrical supplies, and environmental considerations. Worldwide efforts are being made to extract thermal energy from the ground for heating and cooling individual dwellings and industrial and institutional complexes. Aquifer thermal energy storage systems offer a viable option. Often, there is a poor understanding of the problems associated with the well field, resulting in resistance in the consideration and implementation of the technology. Well-field problems include pressure build-up in the reinjection wells resulting in reduced flow conditions. Other problems associated with well-field configuration include wellbore clogging due to sediment accumulation, scaling, degassing or bio-fouling. These problems are often associated with changes in temperature and pressure. The authors examined these problems and presented guidelines to assist in the identification and management of the potential problems. 2 refs., 1 fig.

  11. Results from a workshop on research needs for modeling aquifer thermal energy storage systems

    Energy Technology Data Exchange (ETDEWEB)

    Drost, M K

    1990-08-01

    A workshop an aquifer thermal energy storage (ATES) system modeling was conducted in Seattle, Washington, on November 30 and December 1, 1989 by Pacific Northwest Laboratory (PNL). The goal of the workshop was to develop a list of high-priority research activities that would facilitate the commercial success of ATES. During the workshop, participants reviewed currently available modeling tools for ATES systems and produced a list of significant issues related to modeling ATES systems. Participants assigned a priority to each issue on the list by voting and developed a list of research needs for each of four high-priority research areas; the need for a feasibility study model, the need for engineering design models, the need for aquifer characterization, and the need for an economic model. The workshop participants concluded that ATES commercialization can be accelerated by aggressive development of ATES modeling tools and made specific recommendations for that development. 2 tabs.

  12. Influence of water treatment methods on groundwater in aquifer thermal energy storage

    International Nuclear Information System (INIS)

    An important factor in judging the environmental relevance of an aquifer thermal energy storage plant is whether it requires treatment of the water and by what method. Problems that may call for water treatment are the precipitation of carbonate compounds when the water heats up, the formation of iron oxide hydrates and manganese oxide hydrates, and, possibly, heavier corrosion. The paper describes different water treatment methods: Decarbonization through addition of lye of mineral acid, softening by Ca-Na ion exchange, stabilization of water hardness through lowering of the pH, fluidized-bed heat exchangers, stabilization of hardness through CO2. (BWI)

  13. Impacts of convection on high-temperature aquifer thermal energy storage

    Science.gov (United States)

    Beyer, Christof; Hintze, Meike; Bauer, Sebastian

    2016-04-01

    Seasonal subsurface heat storage is increasingly used in order to overcome the temporal disparities between heat production from renewable sources like solar thermal installations or from industrial surplus heat and the heat demand for building climatisation or hot water supply. In this context, high-temperature aquifer thermal energy storage (ATES) is a technology to efficiently store and retrieve large amounts of heat using groundwater wells in an aquifer to inject or withdraw hot or cold water. Depending on the local hydrogeology and temperature amplitudes during high-temperature ATES, density differences between the injected hot water and the ambient groundwater may induce significant convective flow components in the groundwater flow field. As a consequence, stored heat may accumulate at the top of the storage aquifer which reduces the heat recovery efficiency of the ATES system. Also, an accumulation of heat at the aquifer top will induce increased emissions of heat to overlying formations with potential impacts on groundwater quality outside of the storage. This work investigates the impacts of convective heat transport on the storage efficiency of a hypothetical high-temperature ATES system for seasonal heat storage as well as heat emissions to neighboring formations by numerical scenario simulations. The coupled groundwater flow and heat transport code OpenGeoSys is used to simulate a medium scale ATES system operating in a sandy aquifer of 20 m thickness with an average groundwater temperature of 10°C and confining aquicludes at top and bottom. Seasonal heat storage by a well doublet (i.e. one fully screened "hot" and "cold" well, respectively) is simulated over a period of 10 years with biannual injection / withdrawal cycles at pumping rates of 15 m³/h and for different scenarios of the temperature of the injected water (20, 35, 60 and 90 °C). Simulation results show, that for the simulated system significant convective heat transport sets in when

  14. Site-specific investigations of aquifer thermal energy storage for space and process cooling

    International Nuclear Information System (INIS)

    This paper reports on the Pacific Northwest Laboratory (PNL) that has completed three preliminary site-specific feasibility studies that investigated aquifer thermal energy storage (ATES) for reducing 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. Seasonal or diurnal chill ATES systems could be significantly less expensive than a conventional electrically-driven, load-following chiller system at one of the three sites, depending on the cooling water loop return temperature and presumed future electricity escalation rate. For the other two sites investigated, a chill ATES system would be economically competitive with conventional chillers if onsite aquifer characteristics were improved. Well flow rates at one of the sites were adequate, but the expected thermal recovery efficiency was too low. The reverse of this situation was found at the other site, where the thermal recovery efficiency was expected to be adequate, but well flow rates were too low

  15. Application of multiple-point geostatistics to simulate the effect of small scale aquifer heterogeneity on the efficiency of Aquifer Thermal Energy Storage (ATES)

    Science.gov (United States)

    Possemiers, Mathias; Huysmans, Marijke; Batelaan, Okke

    2015-04-01

    Adequate aquifer characterization and simulation using heat transport models are indispensible for determining the optimal design for Aquifer Thermal Energy Storage (ATES) systems and wells. Recent model studies indicate that meter scale heterogeneities in the hydraulic conductivity field introduce a considerable uncertainty in the distribution of thermal energy around an ATES system and can lead to a reduction in the thermal recoverability. In this paper, the influence of centimeter scale clay drapes on the efficiency of a doublet ATES system and the distribution of the thermal energy around the ATES wells are quantified. Multiple-point geostatistical simulation of edge properties is used to incorporate the clay drapes in the models. The results show that clay drapes have an influence both on the distribution of thermal energy in the subsurface and on the efficiency of the ATES system. The distribution of the thermal energy is determined by the strike of the clay drapes, with the major axis of anisotropy parallel to the clay drape strike. The clay drapes have a negative impact (3.3 - 3.6%) on the energy output in the models without a hydraulic gradient. In the models with a hydraulic gradient, however, the presence of clay drapes has a positive influence (1.6 - 10.2%) on the energy output of the ATES system. It is concluded that it is important to incorporate small scale heterogeneities in heat transport models to get a better estimate on ATES efficiency and distribution of thermal energy.

  16. Application of multiple-point geostatistics to simulate the effect of small-scale aquifer heterogeneity on the efficiency of aquifer thermal energy storage

    Science.gov (United States)

    Possemiers, Mathias; Huysmans, Marijke; Batelaan, Okke

    2015-08-01

    Adequate aquifer characterization and simulation using heat transport models are indispensible for determining the optimal design for aquifer thermal energy storage (ATES) systems and wells. Recent model studies indicate that meter-scale heterogeneities in the hydraulic conductivity field introduce a considerable uncertainty in the distribution of thermal energy around an ATES system and can lead to a reduction in the thermal recoverability. In a study site in Bierbeek, Belgium, the influence of centimeter-scale clay drapes on the efficiency of a doublet ATES system and the distribution of the thermal energy around the ATES wells are quantified. Multiple-point geostatistical simulation of edge properties is used to incorporate the clay drapes in the models. The results show that clay drapes have an influence both on the distribution of thermal energy in the subsurface and on the efficiency of the ATES system. The distribution of the thermal energy is determined by the strike of the clay drapes, with the major axis of anisotropy parallel to the clay drape strike. The clay drapes have a negative impact (3.3-3.6 %) on the energy output in the models without a hydraulic gradient. In the models with a hydraulic gradient, however, the presence of clay drapes has a positive influence (1.6-10.2 %) on the energy output of the ATES system. It is concluded that it is important to incorporate small-scale heterogeneities in heat transport models to get a better estimate on ATES efficiency and distribution of thermal energy.

  17. The University of Minnesota aquifer thermal energy storage (ATES) field test facility -- system description, aquifer characterization, and results of short-term test cycles

    Energy Technology Data Exchange (ETDEWEB)

    Walton, M.; Hoyer, M.C.; Eisenreich, S.J.; Holm, N.L.; Holm, T.R.; Kanivetsky, R.; Jirsa, M.A.; Lee, H.C.; Lauer, J.L.; Miller, R.T.; Norton, J.L.; Runke, H. (Minnesota Geological Survey, St. Paul, MN (United States))

    1991-06-01

    Phase 1 of the Aquifer Thermal Energy Storage (ATES) Project at the University of Minnesota was to test the feasibility, and model, the ATES concept at temperatures above 100{degrees}C using a confined aquifer for the storage and recovery of hot water. Phase 1 included design, construction, and operation of a 5-MW thermal input/output field test facility (FTF) for four short-term ATES cycles (8 days each of heat injection, storage, and heat recover). Phase 1 was conducted from May 1980 to December 1983. This report describes the FTF, the Franconia-Ironton-Galesville (FIG) aquifer used for the test, and the four short-term ATES cycles. Heat recovery; operational experience; and thermal, chemical, hydrologic, and geologic effects are all included. The FTF consists of monitoring wells and the source and storage well doublet completed in the FIG aquifer with heat exchangers and a fixed-bed precipitator between the wells of the doublet. The FIG aquifer is highly layered and a really anisotropic. The upper Franconia and Ironton-Galesville parts of the aquifer, those parts screened, have hydraulic conductivities of {approximately}0.6 and {approximately}1.0 m/d, respectively. Primary ions in the ambient ground water are calcium and magnesium bicarbonate. Ambient temperature FIG ground water is saturated with respect to calcium/magnesium bicarbonate. Heating the ground water caused most of the dissolved calcium to precipitate out as calcium carbonate in the heat exchanger and precipitator. Silica, calcium, and magnesium were significantly higher in recovered water than in injected water, suggesting dissolution of some constituents of the aquifer during the cycles. Further work on the ground water chemistry is required to understand water-rock interactions.

  18. Microbiological and environmental effects of aquifer thermal energy storage - studies at the Stuttgart man-made aquifer and a large-scale model system

    International Nuclear Information System (INIS)

    The storage of thermal energy, either heat or cold, in natural or artificial aquifers creates local perturbations of the indigenous microflora and the environmental properties. Within an international working group of the International Energy Agency (IEA Annex VI) possible environmental impacts of ATES-systems were recognized and investigated. Investigations of storage systems on natural sites, man-made aquifers and large-scale models of impounded aquifers showed changes in microbial populations, but until now no adverse microbiological processes associated with ATES-systems could be documented. However, examinations with a model system indicate an increased risk of environmental impact. Therefore, the operation of ATES-systems should be accompanied by chemical and biological investigations. (orig.)

  19. The underground as a storage facility. Modelling of nuclear waste repositories and aquifer thermal energy stores

    International Nuclear Information System (INIS)

    This thesis, which consists of eleven papers and reports, deals with nuclear waste repositories in solid rock and with aquifer thermal energy storage systems. All these storage systems induce multidimensional, time-variable thermo-hydro-elastic processes in the ground in and around the storage region. The partial differential equations that govern the physical processes are solved analytically in some cases, and in other cases numerical models are developed. Many methods of classical mathematical physics are employed for the solution. The analytical approach provides a deeper physical understanding of the processes and their interactions. At large depths, the salinity of groundwater, and hence its density, often increases downwards. In the first study, the upward buoyancy flow of groundwater in fracture planes due to heat release from the nuclear waste is studied considering the added effect of a salt gradient. The aim of the study is to determine the natural barrier effect caused by the salt. A simple formula for the largest upward displacement from the repository is derived. There may be a strong natural barrier, which is independent of fracture permeabilities. In two papers, the temperature field in rock due to a large rectangular grid of heat-releasing canisters containing nuclear waste is studied. The solution is by superposition divided into different parts. There is a global temperature field due to the large rectangular canister area, while a local field accounts for the remaining heat source problem. A complete analytical solution is presented. In the next set of papers, the thermoelastic response from the rectangular field of nuclear waste is analysed. Another study concerns the use of heat as a tracer to investigate flow in a fracture plane. Two papers deal with the thermohydraulic evaluations of two aquifer thermal energy storage projects in southern Sweden. Both plants have been successfully simulated using models based on conformal flow and entropy

  20. Predicting Formation Damage in Aquifer Thermal Energy Storage Systems Utilizing a Coupled Hydraulic-Thermal-Chemical Reservoir Model

    Science.gov (United States)

    Müller, Daniel; Regenspurg, Simona; Milsch, Harald; Blöcher, Guido; Kranz, Stefan; Saadat, Ali

    2014-05-01

    In aquifer thermal energy storage (ATES) systems, large amounts of energy can be stored by injecting hot water into deep or intermediate aquifers. In a seasonal production-injection cycle, water is circulated through a system comprising the porous aquifer, a production well, a heat exchanger and an injection well. This process involves large temperature and pressure differences, which shift chemical equilibria and introduce or amplify mechanical processes. Rock-fluid interaction such as dissolution and precipitation or migration and deposition of fine particles will affect the hydraulic properties of the porous medium and may lead to irreversible formation damage. In consequence, these processes determine the long-term performance of the ATES system and need to be predicted to ensure the reliability of the system. However, high temperature and pressure gradients and dynamic feedback cycles pose challenges on predicting the influence of the relevant processes. Within this study, a reservoir model comprising a coupled hydraulic-thermal-chemical simulation was developed based on an ATES demonstration project located in the city of Berlin, Germany. The structural model was created with Petrel, based on data available from seismic cross-sections and wellbores. The reservoir simulation was realized by combining the capabilities of multiple simulation tools. For the reactive transport model, COMSOL Multiphysics (hydraulic-thermal) and PHREEQC (chemical) were combined using the novel interface COMSOL_PHREEQC, developed by Wissmeier & Barry (2011). It provides a MATLAB-based coupling interface between both programs. Compared to using COMSOL's built-in reactive transport simulator, PHREEQC additionally calculates adsorption and reaction kinetics and allows the selection of different activity coefficient models in the database. The presented simulation tool will be able to predict the most important aspects of hydraulic, thermal and chemical transport processes relevant to

  1. Combination of aquifer thermal energy storage and enhanced bioremediation: resilience of reductive dechlorination to redox changes.

    Science.gov (United States)

    Ni, Zhuobiao; van Gaans, Pauline; Smit, Martijn; Rijnaarts, Huub; Grotenhuis, Tim

    2016-04-01

    To meet the demand for sustainable energy, aquifer thermal energy storage (ATES) is widely used in the subsurface in urban areas. However, contamination of groundwater, especially with chlorinated volatile organic compounds (CVOCs), is often being encountered. This is commonly seen as an impediment to ATES implementation, although more recently, combining ATES and enhanced bioremediation of CVOCs has been proposed. Issues to be addressed are the high water flow velocities and potential periodic redox fluctuation that accompany ATES. A column study was performed, at a high water flow velocity of 2 m/h, simulating possible changes in subsurface redox conditions due to ATES operation by serial additions of lactate and nitrate. The impacts of redox changes on reductive dechlorination as well as the microbial response of Dehalococcoides (DHC) were evaluated. The results showed that, upon lactate addition, reductive dechlorination proceeded well and complete dechlorination from cis-DCE to ethene was achieved. Upon subsequent nitrate addition, reductive dechlorination immediately ceased. Disruption of microorganisms' retention was also immediate and possibly detached DHC which preferred attaching to the soil matrix under biostimulation conditions. Initially, recovery of dechlorination was possible but required bioaugmentation and nutrient amendment in addition to lactate dosing. Repeated interruption of dechlorination and DHC activity by nitrate dosing appeared to be less easily reversible requiring more efforts for regenerating dechlorination. Overall, our results indicate that the microbial resilience of DHC in biosimulated ATES conditions is sensitive to redox fluctuations. Hence, combining ATES with bioremediation requires dedicated operation and monitoring on the aquifer geochemical conditions. PMID:26711280

  2. Guidelines for conceptual design and evaluation of aquifer thermal energy storage

    Energy Technology Data Exchange (ETDEWEB)

    Meyer, C.F.; Hauz, W.

    1980-10-01

    Guidelines are presented for use as a tool by those considering application of a new technology, aquifer thermal energy storage (ATES). The guidelines will assist utilities, municipalities, industries, and other entities in the conceptual design and evaluation of systems employing ATES. The potential benefits of ATES are described, an overview is presented of the technology and its applications, and rules of thumb are provided for quickly judging whether a proposed project has sufficient promise to warrant detailed conceptual design and evaluation. The characteristics of sources and end uses of heat and chill which are seasonally mismatched and may benefit from ATES (industrial waste heat, cogeneration, solar heat, and winter chill, for space heating and air conditioning) are discussed. Storage and transport subsystems and their expected performance and cost are described. A 10-step methodology is presented for conceptual design of an ATES system and evaluation of its technical and economic feasibility in terms of energy conservation, cost savings, fuel substitution, improved dependability of supply, and abatement of pollution, with examples, and the methodology is applied to a hypothetical proposed ATES system, to illustrate its use.

  3. Analysis of recovery efficiency in high-temperature aquifer thermal energy storage: a Rayleigh-based method

    Science.gov (United States)

    Schout, Gilian; Drijver, Benno; Gutierrez-Neri, Mariene; Schotting, Ruud

    2013-10-01

    High-temperature aquifer thermal energy storage (HT-ATES) is an important technique for energy conservation. A controlling factor for the economic feasibility of HT-ATES is the recovery efficiency. Due to the effects of density-driven flow (free convection), HT-ATES systems applied in permeable aquifers typically have lower recovery efficiencies than conventional (low-temperature) ATES systems. For a reliable estimation of the recovery efficiency it is, therefore, important to take the effect of density-driven flow into account. A numerical evaluation of the prime factors influencing the recovery efficiency of HT-ATES systems is presented. Sensitivity runs evaluating the effects of aquifer properties, as well as operational variables, were performed to deduce the most important factors that control the recovery efficiency. A correlation was found between the dimensionless Rayleigh number (a measure of the relative strength of free convection) and the calculated recovery efficiencies. Based on a modified Rayleigh number, two simple analytical solutions are proposed to calculate the recovery efficiency, each one covering a different range of aquifer thicknesses. The analytical solutions accurately reproduce all numerically modeled scenarios with an average error of less than 3 %. The proposed method can be of practical use when considering or designing an HT-ATES system.

  4. The use of salinity contrast for density difference compensation to improve the thermal recovery efficiency in high-temperature aquifer thermal energy storage systems

    Science.gov (United States)

    van Lopik, Jan H.; Hartog, Niels; Zaadnoordijk, Willem Jan

    2016-02-01

    The efficiency of heat recovery in high-temperature (>60 °C) aquifer thermal energy storage (HT-ATES) systems is limited due to the buoyancy of the injected hot water. This study investigates the potential to improve the efficiency through compensation of the density difference by increased salinity of the injected hot water for a single injection-recovery well scheme. The proposed method was tested through numerical modeling with SEAWATv4, considering seasonal HT-ATES with four consecutive injection-storage-recovery cycles. Recovery efficiencies for the consecutive cycles were investigated for six cases with three simulated scenarios: (a) regular HT-ATES, (b) HT-ATES with density difference compensation using saline water, and (c) theoretical regular HT-ATES without free thermal convection. For the reference case, in which 80 °C water was injected into a high-permeability aquifer, regular HT-ATES had an efficiency of 0.40 after four consecutive recovery cycles. The density difference compensation method resulted in an efficiency of 0.69, approximating the theoretical case (0.76). Sensitivity analysis showed that the net efficiency increase by using the density difference compensation method instead of regular HT-ATES is greater for higher aquifer hydraulic conductivity, larger temperature difference between injection water and ambient groundwater, smaller injection volume, and larger aquifer thickness. This means that density difference compensation allows the application of HT-ATES in thicker, more permeable aquifers and with larger temperatures than would be considered for regular HT-ATES systems.

  5. An Estimate of Energy Available via Microbial Sulfate Reduction at a Quaternary Aquifer in Northern Japan considered for Low Temperature Thermal Energy Storage

    Directory of Open Access Journals (Sweden)

    Seiichiro Ioka

    2014-04-01

    Full Text Available The energy available via microbial sulfate reduction was estimated for a Quaternary aquifer in northern Japan that is a candidate site for low temperature aquifer thermal energy storage. In evaluating whether microbial sulfate reduction proceeded or ceased, it was assumed that electron donor/acceptor concentrations were unchanged by temperature increase. The estimated energy availability via microbial sulfate reduction at 9 °C with no thermal disturbance was 37, 51, and 53 kJ·(mol SO42−−1. The low estimate of 37 kJ·(mol SO42−−1 was attributed to low concentration of SO42−. Excluding the sampling site with low concentration of electron acceptors, energy availability was estimated 52 and 54 kJ·(mol SO42−−1 at 20 °C; 54 and 57 kJ·(mol SO42−−1 at 40 °C; and 57 and 59 kJ·(mol SO42−−1 at 60 °C. These results indicate that possible energy availability via microbial sulfate reduction at approximately 40–60 °C exceeded the range of available energy (compiled from previous studies at which sulfate reduction would cease. Thus, microbial sulfate reduction at this site may proceed at approximately 40–60 °C.

  6. Combining climatic and geo-hydrological preconditions as a method to determine world potential for aquifer thermal energy storage.

    Science.gov (United States)

    Bloemendal, Martin; Olsthoorn, Theo; van de Ven, Frans

    2015-12-15

    A heat pump combined with Aquifer Thermal Energy Storage (ATES) is proven technology to economically and sustainably provide space heating and cooling. The two most important preconditions for the applicability of ATES are favorable climatic conditions and the availability of a suitable aquifer. This paper shows how these two preconditions can be combined to identify where in the world ATES potential is present, or will become present as a consequence of climate change. Countries and regions are identified where regulation and stimulation measures may increase application of ATES technologies and thus help reduce CO2-emissions. Two types of data determine ATES suitability, and their combination with a 3rd identifies potential hot-spots in the world: 1) geo-hydrological conditions, 2) current and projected climate classification and 3) urbanization. Our method combines the data into an ATES-suitability score as explained in this paper. On the one hand the results confirm the suitability for ATES where it is already applied and on the other they identify places where the technology is or will become suitable. About 15% of urban population lived in areas with high potential for ATES at the start of the 21st century, but this figure will decrease to about 5% during the 21st century as a consequence of expected climate change. Around 50% of urban population currently lives in areas of medium ATES suitability, a percentage that will remain constant. Demand for ATES is likely to exceed available subsurface space in a significant part of the urban areas. PMID:26322727

  7. Model-based assessment of the potential of seasonal aquifer thermal energy storage and recovery as a groundwater ecosystem service for the Brussels-Capital Region

    Science.gov (United States)

    Anibas, Christian; Huysmans, Marijke

    2015-04-01

    Urban areas are characterized by their concentrated demand of energy, applying a high pressure on urban ecosystems including atmosphere, soils and groundwater. In the light of global warming, urbanization and an evolving energy system, it is important to know how urbanized areas can contribute to their own energy demands. One option is to use the possibilities aquifers offer as an ecosystem service (BONTE et al., 2011). If used effectively an improvement in air and groundwater quality is achieved. Additionally, the more efficient distribution of the used energy may also lead to a decrease in primary energy consumption (ZUURBIER, 2013). Therefore, investigations of the potential of seasonal aquifer thermal energy storage and recovery (ATES) for the Brussels-Capital Region, Belgium is being conducted. The potential of ATES systems are of special interest for energy demands in high density urban areas because of such infrastructure as office buildings, schools, hospitals and shopping malls. In an open water circuit ATES systems consist of two or more groundwater wells, where in seasonal cycles one subtracts and the other recharges water to the aquifer. Heat pumps use the heat capacity of water for heating or cooling a building. An important limitation of the methodology is the quality of the groundwater used (i.e. precipitation of Fe- or Mn-oxides can decrease the yield). However, ATES systems on the other hand can also improve groundwater quality and groundwater ecosystems. The current knowledge of the potential for ATES systems in the Brussels-Capital Region is based on geological assessments from VITO (2007). The Brussels-Capital Region is divided into a western and eastern section with respect to geology. While the western part has less favorable conditions for ATES, the eastern is composed of the Brussels Sand formation, which is a 20-40 m thick aquifer layer that has the highest potential for ATES systems in the region. By applying groundwater flow and heat

  8. Heat pump for district cooling and heating at Oslo Airport, Gardermoen[Aquifer thermal energy systems (ATES)

    Energy Technology Data Exchange (ETDEWEB)

    Eggen, Geir; Vangsnes, Geir

    2006-07-01

    At Gardermoen, one of the largest groundwater reservoirs in Norway is located. This aquifer is used for both heating and cooling of Gardermoen Airport. In the summer, ground water is pumped from cold wells and used for cooling before it is returned to the warm wells. In winter, this process is turned around, as ground water from the warm wells is used as heat source for the heat pump. The heat pump is mainly designed for cooling, and the design cooling demand is 9 MW. The district cooling water is pre-cooled by the ground water, and post cooled by the combined heat pump/refrigeration plant. The base heat load is covered by the heat pump. Additional heat is supplied from a heat energy central with bio fuels as well as oil heated and electrically heated boilers. During the last years, heat production from the heat pump was about 11 GWh/year, and the heat pump also provides about 8 GWh/year of the cooling demand. In addition, approximately 3 GWh/year cold is produced by direct heat exchange with ground water. Compared with a district heating system heated by fossil fuels, and a conventional refrigeration system for district cooling, the pay back period for the aquifer heat pump system is within a couple of years (author) (ml)

  9. Aquifer Thermal Energy Storage as an ecosystem service for Brussels, Belgium: investigating iron (hydr)oxide precipitation with reactive transport modeling

    Science.gov (United States)

    Anibas, Christian; Possemiers, Mathias; Huysmans, Marijke

    2016-04-01

    In an evolving energy system it is important that urbanized areas contribute to their own energy demands. To reduce greenhouse gas emissions sustainable energy systems with a high efficiency are required, e.g. using urban aquifers as an ecosystem service. Here the potential of seasonal aquifer thermal energy storage and recovery (ATES) for the Brussels-Capital Region, Belgium is investigated. An important shallow geologic formation in the Brussels Capital Region is the Brussels Sand formation, a 20-60 m thick phreatic aquifer. The Brussels Sand Formation is known for its potential for ATES systems, but also for its varying redox and hydraulic conditions. Important limiting factors for ATES systems in the Brussels Sand Formation therefore are the hydraulic conductivity and the geochemical composition of the groundwater. Near the redox boundary iron hydroxide precipitation can negatively influence ATES well performance due to clogging. The interactions between physical processes (e.g. particle transport and clogging in the wider proximity of the ATES well) and chemical processes (e.g. influence of the operation temperatures on precipitation processes) during ATES operation are complex but not well understood. Therefore we constructed numerical groundwater flow models in MODFLOW to estimate maximum pumping and injection rates of different hydraulic conditions and competing water uses in the Brussels Sand Formation. In further steps the thermal potential for ATES was quantified using MT3DMS and the reactive transport model PHT3D was applied to assess the effects of operating ATES systems near the redox boundary. Results show that initial mixing plays an important role in the development of iron(hydr)oxide precipitation around the ATES wells, with the highest concentrations around the cold wells. This behavior is enhanced by the temperature effect; temperature differences of ΔT≈10°C already influence the iron (hydr)oxide concentration. The initial injection into the

  10. Hydraulic characterization of aquifers by thermal response testing

    Science.gov (United States)

    Wagner, Valentin; Blum, Philipp; Bayer, Peter

    2014-05-01

    Temperature as a major physical quantity of the subsurface, and naturally occurring thermal anomalies are recognized as promising passive tracers to characterize the subsurface. Accelerated by the increasing popularity of geothermal energy, also active thermal field experiments have gained interest in hydrogeology. Such experiments involve artificial local ground heating or cooling. Among these, the thermal response test (TRT) is one of the most established field investigation techniques in shallow geothermal applications. It is a common method to investigate important subsurface heat transport parameters to design sustainable ground-source heat pump (GSHP) systems. During the test, the borehole heat exchanger (BHE) is heated up with a defined amount of energy by circulating a heat carrier fluid. By comparing temperature change between BHE inlet and outlet, the ability of the BHE to transfer heat or cold to the ambient ground is assessed. However, standard interpretation does not provide any insight into the governing processes of in-situ heat transfer. We utilize a groundwater advection sensitive TRT evaluation approach based on the analytical moving line source equation. It is shown that the TRT as a classical geothermal field test can also be used as a hydrogeological field test. Our approach benefits from the fact that thermal properties, such as thermal conductivity, of natural aquifers typically are much less variable than hydraulic properties, such as hydraulic conductivity. It is possible to determine a relatively small hydraulic conductivity range with our TRT evaluation approach, given realistic ranges for thermal conductivity, volumetric heat capacity, thermal dispersivity and thermal borehole resistance. The method is successfully tested on a large-scale geothermal laboratory experiment (9 m × 6 m × 4.5 m) and with a commercially performed TRT in the field scale. The laboratory experiment consists of a layered artificial aquifer, which is penetrated

  11. User manual for AQUASTOR: a computer model for cost analysis of aquifer thermal-energy storage oupled with district-heating or cooling systems. Volume II. Appendices

    Energy Technology Data Exchange (ETDEWEB)

    Huber, H.D.; Brown, D.R.; Reilly, R.W.

    1982-04-01

    A computer model called AQUASTOR was developed for calculating the cost of district heating (cooling) using thermal energy supplied by an aquifer thermal energy storage (ATES) system. the AQUASTOR Model can simulate ATES district heating systems using stored hot water or ATES district cooling systems using stored chilled water. AQUASTOR simulates the complete ATES district heating (cooling) system, which consists of two prinicpal parts: the ATES supply system and the district heating (cooling) distribution system. The supply system submodel calculates the life-cycle cost of thermal energy supplied to the distribution system by simulating the technical design and cash flows for the exploration, development, and operation of the ATES supply system. The distribution system submodel calculates the life-cycle cost of heat (chill) delivered by the distribution system to the end-users by simulating the technical design and cash flows for the construction and operation of the distribution system. The model combines the technical characteristics of the supply system and the technical characteristics of the distribution system with financial and tax conditions for the entities operating the two systems into one techno-economic model. This provides the flexibility to individually or collectively evaluate the impact of different economic and technical parameters, assumptions, and uncertainties on the cost of providing district heating (cooling) with an ATES system. This volume contains all the appendices, including supply and distribution system cost equations and models, descriptions of predefined residential districts, key equations for the cooling degree-hour methodology, a listing of the sample case output, and appendix H, which contains the indices for supply input parameters, distribution input parameters, and AQUASTOR subroutines.

  12. Thermal tracer tests for characterizing a shallow alluvial aquifer

    OpenAIRE

    Wildemeersch, Samuel; Klepikova, Maria; Jamin, Pierre; Orban, Philippe; Hermans, Thomas; Brouyère, Serge; Dassargues, Alain

    2014-01-01

    Using heat as an active tracer in different types of aquifers is a topic of increasing interest [e.g. Vandenbohede et al.; 2008, Wagner et al., 2013; Read et al., 2013]. In this study, we investigate the potential interest of coupling heat and solute tracer tests for characterization of a shallow alluvial aquifer. A thermal tracer test was conducted in the alluvial aquifer of the Meuse River, Belgium. The tracing experiment consisted in simultaneously injecting heated water and a dye tracer i...

  13. Thermal Energy Storage: Fourth Annual Review Meeting

    Science.gov (United States)

    1980-01-01

    The development of low cost thermal energy storage technologies is discussed in terms of near term oil savings, solar energy applications, and dispersed energy systems for energy conservation policies. Program definition and assessment and research and technology development are considered along with industrial storage, solar thermal power storage, building heating and cooling, and seasonal thermal storage. A bibliography on seasonal thermal energy storage emphasizing aquifer thermal energy is included.

  14. Seasonal Thermal Energy Storage Program

    Science.gov (United States)

    Minor, J. E.

    1980-01-01

    The Seasonal Thermal Energy Storage (STES) Program designed to demonstrate the storage and retrieval of energy on a seasonal basis using heat or cold available from waste or other sources during a surplus period is described. Factors considered include reduction of peak period demand and electric utility load problems and establishment of favorable economics for district heating and cooling systems for commercialization of the technology. The initial thrust of the STES Program toward utilization of ground water systems (aquifers) for thermal energy storage is emphasized.

  15. Cyclic injection, storage, and withdrawal of heated water in a sandstone aquifer at St. Paul, Minnesota: Field observations, preliminary model analysis, and aquifer thermal efficiency

    Science.gov (United States)

    Miller, Robert T.

    1989-01-01

    In May 1980, the University of Minnesota began a project to evaluate the feasibility of storing heated (150 °C (degree Celsius)) water in the deep (180 to 240 m (meters)) Franconia-Ironton-Galesville aquifer and later recovering it for space heating. The Aquifer Thermal-Energy Storage (ATES) system was doublet-well design in which the injection/withdrawal wells were spaced approximately 250 m apart. High-temperature water from the University's steam-generation facilities supplied heat for injection. Water was pumped from one of the wells through a heat exchanger, where heat was added or removed. Water then was injected back into the aquifer through the other well. The experimental plan for testing the ATES system consisted of a series of short-term hot-water injection, storage, and withdrawal cycles. Each cycle was 24-days long, and each injection, storage, and withdrawal step of the cycle was 8 days.

  16. Thermodynamic impact of aquifer permeability on the performance of a compressed air energy storage plant

    International Nuclear Information System (INIS)

    Highlights: • Design procedure of an aquifer compressed air energy storage system was proposed. • An approach to select aquifers with adequate permeability was presented. • Applied an exergy analysis to exam the impact of permeability on plant economics. • The exergy destruction in the aquifer was reduced as the permeability increased. - Abstract: Economic, large-scale energy storage technology plays a key role in enabling the utility industry to integrate more renewable energy sources into the grid. Compressed air energy storage in porous geological formations has the potential to become one of the principal energy storage technologies in the future. Storing pressurized air in aquifers has several advantages, including large storage capacity, geologically widespread availability, relatively constant pressure, and relatively low construction cost. The performance of a compressed air energy storage plant is influenced by the subsurface reservoir properties. In this paper, the design criteria, calculation procedure, and exergy analysis approach to quantify the influence of aquifer permeability on compressed air energy storage plants are proposed. A case-study model was built to simulate a compressed air energy storage plant using aquifers with porosities of 30% and different permeabilities (0.01–1.0 darcies). The exergy destruction rates and exergy and thermal efficiencies were calculated. The results indicated that as the permeability increased, the exergy destruction due to a pressure drop of working fluid in an aquifer decreased; as the permeability increased, both thermal and exergy efficiencies increased, and the net output of the plant increased. The benefits are more obvious when the permeability increased from low (⩽0.05 darcies) to medium–high values (⩾0.25 darcies)

  17. Aquifers

    Data.gov (United States)

    Earth Data Analysis Center, University of New Mexico — This map layer contains the shallowest principal aquifers of the conterminous United States, Hawaii, Puerto Rico, and the U.S. Virgin Islands, portrayed as...

  18. Thermal insights of the Greenland ice sheet perennial firn aquifer

    Science.gov (United States)

    Forster, R. R.; Miège, C.; Koenig, L.; Brucker, L.

    2013-12-01

    The Greenland ice sheet hydrology is characterized by a complex system and is triggered essentially by surface melt starting late spring to early summer each year. Understanding the hydrologic system for the ice sheet remains important to address ice dynamics and surface mass balance questions. In April 2011, in Southeast Greenland, field work was conducted and firn-core drilling identified the presence of liquid water persisting through the winter without freezing. This observed feature is named perennial firn aquifer (PFA) and can be mapped by the Accumulation Radar on board of the NASA Operation IceBridge mission. Even if the extent of this feature can be constrained by remote sensing techniques its formation and persistence mechanism remain unclear. Thermal behavior of the PFA is a key parameter to monitor in order to understand melting and refreezing processes at the PFA location. The PFA-13 site (66.18°N, 39.04°W and 1563 m), located near the 2011 site where the PFA was first identified, was revisited in early April 2013 for further investigations of the aquifer. To characterize the PFA thermal regime and seasonal evolution, we installed two thermistor strings . They are used to record the vertical temperature evolution for a year, from the surface to the bottom of the PFA and below. The data are being uploaded daily via satellite link. Progressive heating of the firn pack is observed from June 15th to the end of July 2013, by then, the entire firn column from the surface to 12 m depth (top of PFA) is at 0 °C. This observation brings evidence that meltwater can reach the depth of 12 m in the firn, during one and a half months. By the end of the summer, refreezing is expected from near the surface and the cold surface temperatures will slowly penetrate into the firn. In addition, freshly fallen snow, usually > 2 m over the course of a winter, will help insulate the remaining liquid water within the firn from the surface. We will present the time series of

  19. Combination of thermal energy storage and soil reclamation

    International Nuclear Information System (INIS)

    As the reports from the Netherlands (Sniders, 1993), Sweden (Andersson, 1993), Canada (Cruickshanks, 1993) and Switzerland (Saugy, 1983) show, aquifer thermal energy storage in many cases is profitable already in itself. There is evidence justifying the assumption that it may be possible to combine thermal energy storage with soil reclamation. The temperature increase can be harnessed for more rapid degradation of pollutants. In this case there is no doubt that aquifer thermal energy storage will be both ecologically acceptable and economically worth-while. A corresponding project is in the planning stage. (orig.)

  20. Integrated assessment of variable density-viscosity groundwater flow for a high temperature mono-well aquifer thermal energy storage (HT-ATES) system in a geothermal reservoir

    NARCIS (Netherlands)

    Zeghici, Răzvan Mihai; Oude Essink, Gualbert H P; Hartog, Niels; Sommer, Wijbrand

    2015-01-01

    The use of groundwater systems for heat storage increasingly gains interest among water managers, policy makers and researchers as a way to increase the efficiency of energy production and to allow the re-use of waste heat. Typically, mono-well storage systems are thought to require the use of separ

  1. Integrated assessment of variable density-viscosity groundwater flow for a high temperature mono-well aquifer thermal energy storage (HT-ATES) system in a geothermal reservoir

    NARCIS (Netherlands)

    Zeghici, Răzvan Mihai; Oude Essink, Gualbert H.P.; Hartog, Niels; Sommer, Wijb

    2015-01-01

    The use of groundwater systems for heat storage increasingly gains interest among water managers, policy makers and researchers as a way to increase the efficiency of energy production and to allow the re-use of waste heat. Typically, mono-well storage systems are thought to require the use of se

  2. Thermal pulse energy harvesting

    International Nuclear Information System (INIS)

    This paper presents a new method to enhance thermal energy harvesting with pulsed heat transfer. By creating a phase shift between the hot and cold sides of an energy harvester, periodically pulsed heat flow can allow an available temperature gradient to be concentrated over a heat engine during each thermal pulse, rather than divided between the heat engine and a heat sink. This effect allows the energy harvester to work at maximum power and efficiency despite an otherwise unfavorable heat engine–heat sink thermal resistance ratio. In this paper, the analysis of a generalized energy harvester model and experiments with a mechanical thermal switch demonstrate how the pulse mode can improve the efficiency of a system with equal engine and heat sink thermal resistances by over 80%, although at reduced total power. At a 1:2 engine–sink resistance ratio, the improvement can simultaneously exceed 60% in power and 15% in efficiency. The thermal pulse strategy promises to enhance the efficiency and power density of a variety of systems that convert thermal energy, from waste heat harvesters to the radioisotope power systems on many spacecraft. - Highlights: • A thermal pulse operating mode can increase the maximum power of many thermal energy harvesting systems. • Two modes of pulsed heat transfer were modeled and compared to proof-of-concept experiments. • At a 1:2 heat engine–heat sink thermal resistance ratio, the enhancement exceeds 60% in power and 15% in efficiency

  3. Thermal modeling of a greenhouse integrated to an aquifer coupled cavity flow heat exchanger system

    Energy Technology Data Exchange (ETDEWEB)

    Sethi, V.P. [Department of Mechanical Engineering, Punjab Agricultural University, Ludhiana 141 008, Punjab (India); Sharma, S.K. [Energy Research Centre, Panjab University, Chandigarh 160 017, Punjab (India)

    2007-06-15

    A thermal model is developed for heating and cooling of an agricultural greenhouse integrated with an aquifer coupled cavity flow heat exchanger system (ACCFHES). The ACCFHES works on the principal of utilizing deep aquifer water available at the ground surface through an irrigation tube well already installed in every agricultural field at constant year-round temperature of 24 C. The analysis is based on the energy balance equations for different components of the greenhouse. Using the derived analytical expressions, a computer program is developed in C{sup ++} for computing the hourly greenhouse plant and room air temperature for various design and climatic parameters. Experimental validation of the developed model is carried out using the measured plant and room air temperature data of the greenhouse (in which capsicum is grown) for the winter and summer conditions of the year 2004-2005 at Chandigarh (31 N and 78 E), Punjab, India. It is observed that the predicted and measured values are in close agreement. Greenhouse room air and plant temperature is maintained 6-7 K and 5-6 K below ambient, respectively for an extreme summer day and 7-8 K and 5-6 K above ambient, respectively for an extreme winter night. Finally, parametric studies are conducted to observe the effect of various operating parameters such as mass of the plant, area of the plant, mass flow rate of the circulating air and area of the ACCFHES on the greenhouse room air and plant temperature. (author)

  4. Thermal energy transformer

    Science.gov (United States)

    Berdahl, C. M.; Thiele, C. L. (Inventor)

    1979-01-01

    For use in combination with a heat engine, a thermal energy transformer is presented. It is comprised of a flux receiver having a first wall defining therein a radiation absorption cavity for converting solar flux to thermal energy, and a second wall defining an energy transfer wall for the heat engine. There is a heat pipe chamber interposed between the first and second walls having a working fluid disposed within the chamber and a wick lining the chamber for conducting the working fluid from the second wall to the first wall. Thermal energy is transferred from the radiation absorption cavity to the heat engine.

  5. Thermal energy storage

    Science.gov (United States)

    Grodzka, P. G.; Picklesimer, E. A.

    1978-01-01

    The general scope of study on thermal energy storage development includes: (1) survey and review possible concepts for storing thermal energy; (2) evaluate the potentials of the surveyed concepts for practical applications in the low and high temperature ranges for thermal control and storage, with particular emphasis on the low temperature range, and designate the most promising concepts; and (3) determine the nature of further studies required to expeditiously convert the most promising concept(s) to practical applications. Cryogenic temperature control by means of energy storage materials was also included.

  6. Geothermal energy and heat storage in aquifers

    NARCIS (Netherlands)

    Ewalts, W.P.G.; Geluk, M.C.; Heederik, J.P.; Huurdeman, A.J.M.; Mourik, G.J. van; Postma, A.D.; Snijders, A.L.; Walter, F.; Willemsen, A.

    1988-01-01

    After the first energy crisis in 1973 various research programmes to do with energy conservation and diversification of energy resources were set up in the Netherlands. A number of these were directed to the rest of the subsoil for the following purposes: - the extraction of geothermal energy from g

  7. Geology of hole drill thermal infra basaltic (Guarani Aquifer System) in Salto Uruguay

    International Nuclear Information System (INIS)

    This paper deals with the lithological description of a thermal infrabasaltic (Guarani Aquifer System) hole drill cutting in Dayman (Kanarek Hotel), Salto department (Uruguay). This hole drill shows 152 meters of Buena Vista Formation (Upper Permian- Lower Triassic), 188 meters of Tacuarembo Formation (Upper Jurassic-Lower Cretaceous) and 940meters of Arapey Formation (Lower Cretaceous). Petrographical studies of six basaltic levels were done

  8. Development of in-aquifer heat testing for high resolution subsurface thermal-storage capability characterisation

    Science.gov (United States)

    Seibertz, Klodwig Suibert Oskar; Chirila, Marian Andrei; Bumberger, Jan; Dietrich, Peter; Vienken, Thomas

    2016-03-01

    The ongoing transition from fossil fuels to alternative energy source provision has resulted in increased geothermal uses as well as storage of the shallow subsurface. Existing approaches for exploration of shallow subsurface geothermal energy storage often lack the ability to provide information concerning the spatial variability of thermal storage parameters. However, parameter distributions have to be known to ensure that sustainable geothermal use of the shallow subsurface can take place - especially when it is subject to intensive usage. In this paper, we test a temperature decay time approach to obtain in situ, direct, qualitative, spatial high-resolution information about the distribution of thermal storage capabilities of the shallow subsurface. To achieve this, temperature data from a high-resolution Fibre-Optic-Distributed-Temperature-Sensing device, as well as data from conventional Pt100-temperature-sensors were collected during a heat injection test. The latter test was used to measure the decay time of temperature signal dissipation of the subsurface. Signal generation was provided by in-aquifer heating with a temperature self-regulating electric heating cable. Heating was carried out for 4.5 days. After this, a cooling period of 1.5 weeks was observed. Temperature dissipation data was also compared to Direct-Push-derived high-resolution (hydro-)geological data. The results show that besides hydraulic properties also the bedding and compaction state of the sediment have an impact on the thermal storage capability of the saturated subsurface. The temperature decay time approach is therefore a reliable method for obtaining information regarding the qualitative heat storage capability of heterogeneous aquifers for the use with closed loop system geothermal storage systems. Furthermore, this approach is advantageous over other commonly used methods, e.g. soil-sampling and laboratory analysis, as even small changes in (hydro-)geological properties lead to

  9. Ocean Thermal Energy.

    Science.gov (United States)

    Berkovsky, Boris

    1987-01-01

    Describes Ocean Thermal Energy Conservation (OTEC) as a method for exploiting the temperature difference between warm surface waters of the sea and its cold depths. Argues for full-scale demonstrations of the technique for producing energy for coastal regions. (TW)

  10. Groundwater thermal-effective injection systems in shallow aquifers: possible alternatives to vertical water wells

    Science.gov (United States)

    Lo Russo, Stefano; Taddia, Glenda; Cerino Abdin, Elena

    2014-05-01

    Urbanized areas have environmental features that may influence the development of low-enthalpy geothermal systems and the choice of the most suitable among the available (roughly earth-coupled closed-loop and groundwater open-loop type). In particular, if compared to less anthropized areas, some characteristic urban elements require particular attention: underground extensive use, contamination of groundwater, interference between the systems, authorization procedures and planning restrictions, the competition with cogeneration systems and the impact on emissions of pollutants. In this general context, the increasing implementation in several areas of the world of the open-loop groundwater heat pumps technology which discharge into the aquifer for cooling and heating buildings, could potentially cause, even in the short term, a significant environmental impact associated with thermal interference with groundwater, particularly in the shallow aquifers. The discharge of water at different temperatures compared to baseline (warmer in summer and colder in winter) poses a number of problems in relation to the potential functionality of many existing situations of use of the groundwater (drinking water wells, agricultural, industrial, etc.). In addition, there may be cases of interference between systems, especially in the more densely urbanized areas. Appropriate hydrogeological investigations should be performed for the characterization of the main hydrogeological parameters of the subsoil at the considered site in order to minimize the environmental impact of discharges into aquifers. The current Italian legislation related to withdrawals and discharges into aquifers designs a framework suitable for the protection of groundwater and induce deciding the best configuration of the plant with a case by case approach. An increased contact area between the dispersant system and the ground makes it possible to affect a greater volume of aquifer and, consequently, reduce the

  11. Contribution to the study of the energetic valorisation of shallow aquifers. Experiment of thermal storage in groundwater

    International Nuclear Information System (INIS)

    Shallow aquifers display two interesting aspects regarding energy: because of their generally constant temperature, they are first a natural heat source which perfectly suits the use of heat pumps, notably for the heating of building, and secondly, it is conceivable to locally store there a large quantity of heat at low cost. Thus, the assessment of conditions of thermal use of these aquifers requires the knowledge of the heat transfer mechanism in porous underground environment. This research thesis addresses the mathematical study and interpretation of the thermal behaviour of a groundwater table submitted to a seasonal storage of heat by injection of hot water. More specifically and within the context of a research programme on solar energy and housing launched by the Plan Construction (a public body in charge of incentive research), the objectives were to perform, in situ and at a significant scale, such a seasonal storage, and to interpret the results of a numerical model in order to validate numerical tools and the value of the characteristic thermal-hydraulic parameters of these groundwater tables, as well as the way to measure them. The author addresses the mathematical and numerical approach of the problem of heat storage in groundwater tables, describes experimental conditions, and discusses the numerical interpretation while justifying hypotheses adopted for the simulation

  12. On Permeability Dynamics in Carbonaceous Aquifers used in Energy Storage Applications

    Science.gov (United States)

    Brady, Ds; Tilley, Bs; Ueckert, M.; Baumann, T.

    2015-11-01

    Geothermal energy harvesting applications use deep groundwater aquifers to store harvested energy. The impact of this additional energy to the aquifer chemistry is crucial for long-term operation. Gaseous CO2 is added to the injected water to compensate potential precipitates of carbonates and to prevent structural changes to the aquifer. Both of these effects affect the local chemical equilibrium of the aquifer, and we consider an effective model through homogenization which captures the hydrochemistry, heat transfer, fluid flow and permeability dynamics of the aquifer as heated fluid is added to the aquifer (injection), and as it is later removed (production). The impact of these different physical mechanisms of the heat storage performance of the aquifer is discussed. Support from the Bavarian State Ministry for the Economy is gratefully acknowledged.

  13. CALORSTOCK'94. Thermal energy storage. Better economy, environment, technology

    International Nuclear Information System (INIS)

    This publication is the first volume of the proceedings of CALORSTOCK'94, the sixth international conference on thermal energy storage held in Espoo, Finland on August 22-25, 1994. This volume contains 58 presentations from the following six sessions: Aquifer storage, integration into energy systems, Simulation models and design tools, IEA energy conservation through energy storage programme workshop, Earth coupled storage, District heating and utilities

  14. Solar thermal energy receiver

    Science.gov (United States)

    Baker, Karl W. (Inventor); Dustin, Miles O. (Inventor)

    1992-01-01

    A plurality of heat pipes in a shell receive concentrated solar energy and transfer the energy to a heat activated system. To provide for even distribution of the energy despite uneven impingement of solar energy on the heat pipes, absence of solar energy at times, or failure of one or more of the heat pipes, energy storage means are disposed on the heat pipes which extend through a heat pipe thermal coupling means into the heat activated device. To enhance energy transfer to the heat activated device, the heat pipe coupling cavity means may be provided with extensions into the device. For use with a Stirling engine having passages for working gas, heat transfer members may be positioned to contact the gas and the heat pipes. The shell may be divided into sections by transverse walls. To prevent cavity working fluid from collecting in the extensions, a porous body is positioned in the cavity.

  15. Article for thermal energy storage

    Science.gov (United States)

    Salyer, Ival O.

    2000-06-27

    A thermal energy storage composition is provided which is in the form of a gel. The composition includes a phase change material and silica particles, where the phase change material may comprise a linear alkyl hydrocarbon, water/urea, or water. The thermal energy storage composition has a high thermal conductivity, high thermal energy storage, and may be used in a variety of applications such as in thermal shipping containers and gel packs.

  16. Thermal Energy Conversion Branch

    Science.gov (United States)

    Bielozer, Matthew C.; Schreiber, Jeffrey, G.; Wilson, Scott D.

    2004-01-01

    The Thermal Energy Conversion Branch (5490) leads the way in designing, conducting, and implementing research for the newest thermal systems used in space applications at the NASA Glenn Research Center. Specifically some of the most advanced technologies developed in this branch can be broken down into four main areas: Dynamic Power Systems, Primary Solar Concentrators, Secondary Solar Concentrators, and Thermal Management. Work was performed in the Dynamic Power Systems area, specifically the Stirling Engine subdivision. Today, the main focus of the 5490 branch is free-piston Stirling cycle converters, Brayton cycle nuclear reactors, and heat rejection systems for long duration mission spacecraft. All space exploring devices need electricity to operate. In most space applications, heat energy from radioisotopes is converted to electrical power. The Radioisotope Thermoelectric Generator (RTG) already supplies electricity for missions such as the Cassini Spacecraft. The focus of today's Stirling research at GRC is aimed at creating an engine that can replace the RTG. The primary appeal of the Stirling engine is its high system efficiency. Because it is so efficient, the Stirling engine will significantly reduce the plutonium fuel mission requirements compared to the RTG. Stirling is also being considered for missions such as the lunar/Mars bases and rovers. This project has focused largely on Stirling Engines of all types, particularly the fluidyne liquid piston engine. The fluidyne was developed by Colin D. West. This engine uses the same concepts found in any type of Stirling engine, with the exception of missing mechanical components. All the working components are fluid. One goal was to develop and demonstrate a working Stirling Fluidyne Engine at the 2nd Annual International Energy Conversion Engineering Conference in Providence, Rhode Island.

  17. Cyclic injection, storage, and withdrawal of heated water in a sandstone aquifer at St. Paul, Minnesota: Analysis of thermal data and nonisothermal modeling of short-term test cycles

    Science.gov (United States)

    Miller, Robert T.; Delin, G.N.

    1994-01-01

    In May 1980, the University of Minnesota began a project to evaluate the feasibility of storing heated water (150 degrees Celsius) in the Franconia-Ironton-Galesville aquifer (180 to 240 meters below land surface) and later recovering it for space heating. The University's steam-generation facilities supplied high-temperature water for injection. The Aquifer Thermal-Energy Storage system is a doublet-well design in which the injection-withdrawal wells are spaced approximately 250 meters apart. Water was pumped from one of the wells through a heat exchanger, where heat was added or removed. This water was then injected back into the aquifer through the other well.

  18. Ocean thermal energy conversion

    International Nuclear Information System (INIS)

    Ocean Thermal Energy Conversion (OTEC) systems utilize the natural temperature difference that exists between the warm waters of the ocean surface and the colder waters of the deep ocean to drive a power plant. This temperature difference, caused by the heating effect of the sun, exists 24 hours a day allowing OTEC plants to operate continuously. It is generally considered that a temperature difference of the order of 20 deg. C would be required for the economic operation of an OTEC plant and this may be found in the tropical regions of the world. The principle of OTEC is simple, but the low thermal conversion efficiency when operating with such small temperature differences requires enormous flows of water for a reasonable power output and necessitates enormous components which tend to be expensive. The high capital cost of an OTEC plant suggests that the market will be greatest where its competition, electricity from fossil fuels, is most expensive; for example, island communities currently relying on imported oil. Although OTEC has been proven at the small scale and could be expected to operate at a larger one, there are few plants and OTEC seems unlikely to play anything more than a minor role as a generator of the world's electricity in the foreseeable future. It is primarily poor economics which militate against its exploitation as a renewable energy technology. (author). 4 refs, 3 figs

  19. Experimental and economic study of a greenhouse thermal control system using aquifer water

    Energy Technology Data Exchange (ETDEWEB)

    Sethi, V.P. [Department of Mechanical Engineering, Punjab Agricultural University, Ludhiana 141 008, Punjab (India)]. E-mail: vpsethi68@yahoo.co.in; Sharma, S.K. [Energy Research Centre, Punjab University, Chandigarh 160 017, Punjab (India)

    2007-01-15

    Underground aquifer water is used for thermal control (heating as well as cooling) of a greenhouse in which chilli and capsicum are grown. Year round performance of the designed system is experimentally evaluated and presented. The designed system utilizes the constant temperature aquifer water available on the ground surface at around 24 deg. C (year round) in the agricultural field through deep tubewell used for irrigation purposes for heating a greenhouse in winter nights and cooling in summer days. Experimental performance of the designed system is tested during a full winter as well as for summer conditions. To enhance the efficiency of the system and to improve relative humidity during extreme summer conditions, a simple evaporative cooling process is also added within the same designed system. The experimental results show that the average greenhouse room air temperature is maintained 7-9 deg. C above ambient during winter nights and 6-7 deg. C below ambient in summer days besides decreasing the daily temperature fluctuations inside the greenhouse. Improvement in the average relative humidity during extreme summer conditions is also observed. Technoeconomic analysis of the greenhouse integrated to the designed aquifer coupled cavity flow heat exchanger system (ACCFHES) is also conducted based on the yield of capsicum and chilli crops and compared with those of the greenhouse without any thermal control system and the open field condition yields. An economic comparison of the ACCFHES has also been made with other existing thermal control technologies such as the earth air heat exchanger system, ground air collector, evaporative cooling using foggers and a fan and pad system.

  20. Waste energy harvesting mechanical and thermal energies

    CERN Document Server

    Ling Bing, Kong; Hng, Huey Hoon; Boey, Freddy; Zhang, Tianshu

    2014-01-01

    Waste Energy Harvesting overviews the latest progress in waste energy harvesting technologies, with specific focusing on waste thermal mechanical energies. Thermal energy harvesting technologies include thermoelectric effect, storage through phase change materials and pyroelectric effect. Waste mechanical energy harvesting technologies include piezoelectric (ferroelectric) effect with ferroelectric materials and nanogenerators. The book aims to strengthen the syllabus in energy, materials and physics and is well suitable for students and professionals in the fields.

  1. Thermal energy storage application areas

    Energy Technology Data Exchange (ETDEWEB)

    1979-03-01

    The use of thermal energy storage in the areas of building heating and cooling, recovery of industrial process and waste heat, solar power generation, and off-peak energy storage and load management in electric utilities is reviewed. (TFD)

  2. Seasonal sensible thermal energy storage solutions

    OpenAIRE

    Lavinia Gabriela SOCACIU

    2012-01-01

    The thermal energy storage can be defined as the temporary storage of thermal energy at high or low temperatures. Thermal energy storage is an advances technology for storing thermal energy that can mitigate environmental impacts and facilitate more efficient and clean energy systems. Seasonal thermal energy storage has a longer thermal storage period, generally three or more months. This can contribute significantly to meeting society`s need for heating and cooling. The objectives of thermal...

  3. Transboundary geothermal resources of the Mura-Zala basin: a need for joint thermal aquifer management of Slovenia and Hungary

    Directory of Open Access Journals (Sweden)

    Annamaria Nador

    2012-12-01

    Full Text Available Large transboundary Upper Miocene geothermal sandy aquifers which are widely utilized by both countries forbalneological and direct heat purposes exist in the Slovenian-Hungarian border region. In NE Slovenia the totaldirect heat use was 382 TJ in 2010, while in SW Hungary it was 648 TJ, including utilization from basement reservoirs.The total installed capacity of the 13 Slovenian users was 38.8 MWt, while that of the 29 Hungarian userswas 70.6 MWt. Utilisation takes place without harmonized management strategies which might endanger the longtermsustainability of these systems. We aimed to overcome this by delineating a transboundary thermal groundwaterbody (TTGWB Mura-Zala with an aerial extent of 4,974 km2 and with vertical extent between depths 500–2,200 m, which was done based on detailed geological, hydrological, geochemical and geothermal models as wellas numerical modelling. The regional groundwater flow in the Mura-Zala TTGWB is from west to east in general,the modeled cross-border flow is approximately 50 l/s. At present, thermal water abstraction rates from the Mura/Újfalu Fm. (61.8 l/s in the Slovenian and 67.3 l/s in the Hungarian part of the TTGWB does not endanger the goodregional quantity status of the water body, and this should be maintained by allowing a maximum increase of thermalwater abstraction 3.5 times higher than today. However, to achieve target numbers for an increased proportionof geothermal energy in the total energy mix in both countries, we suggest that increase of thermal efficiency andre-injection should be prioritized apart from the higher thermal water abstraction with setting up limit of themaximum allowable drawdown.

  4. Ocean Thermal Extractable Energy Visualization

    Energy Technology Data Exchange (ETDEWEB)

    Ascari, Matthew [Lockheed Martin Corporation, Bethesda, MD (United States)

    2012-10-28

    The Ocean Thermal Extractable Energy Visualization (OTEEV) project focuses on assessing the Maximum Practicably Extractable Energy (MPEE) from the world’s ocean thermal resources. MPEE is defined as being sustainable and technically feasible, given today’s state-of-the-art ocean energy technology. Under this project the OTEEV team developed a comprehensive Geospatial Information System (GIS) dataset and software tool, and used the tool to provide a meaningful assessment of MPEE from the global and domestic U.S. ocean thermal resources.

  5. Ocean Thermal Energy Conversion (OTEC)

    Science.gov (United States)

    Lavi, A.

    1977-01-01

    Energy Research and Development Administration research progress in Ocean Thermal Energy Conversion (OTEC) is outlined. The development program is being focused on cost effective heat exchangers; ammonia is generally used as the heat exchange fluid. Projected costs for energy production by OTEC vary between $1000 to $1700 per kW.

  6. Cyclic injection, storage, and withdrawal of heated water in a sandstone aquifer at St. Paul, Minnesota--Analysis of thermal data and nonisothermal modeling of short-term test cycles

    Science.gov (United States)

    Miller, Robert T.; Delin, G.N.

    2002-01-01

    In May 1980, the University of Minnesota began a project to evaluate the feasibility of storing heated water (150 degrees Celsius) in the Franconia-Ironton Galesville aquifer (183 to 245 meters below land surface) and later recovering it for space heating. The University's steam-generation facilities supplied high-temperature water for injection. The Aquifer Thermal-Energy Storage system is a doublet-well design in which the injection-withdrawal wells are spaced approximately 250 meters apart. Water was pumped from one of the wells through a heat exchanger, where heat was added or removed. This water was then injected back into the aquifer through the other well. Four short-term test cycles were completed. Each cycle consisted of approximately equal durations of injection and withdrawal ranging from 5.25 to 8.01 days. Equal rates of injection and withdrawal, ranging from 17.4 to 18.6 liters per second, were maintained for each short-term test cycle. Average injection temperatures ranged from 88.5 to 117.9 degrees Celsius. Temperature graphs for selected depths at individual observation wells indicate that the Ironton and Galesville Sandstones received and stored more thermal energy than the upper part of the Franconia Formation. Clogging of the Ironton Sandstone was possibly due to precipitation of calcium carbonate or movement of fine-grain material or both. Vertical-profile plots indicate that the effects of buoyancy flow were small within the aquifer. A three-dimensional, anisotropic, nonisothermal, ground-water-flow, and thermal-energy-transport model was constructed to simulate the four short-term test cycles. The model was used to simulate the entire short-term testing period of approximately 400 days. The only model properties varied during model calibration were longitudinal and transverse thermal dispersivities, which, for final calibration, were simulated as 3.3 and 0.33 meters, respectively. The model was calibrated by comparing model-computed results to

  7. Thermal energy storage and transport

    Science.gov (United States)

    Hausz, W.

    1980-01-01

    The extraction of thermal energy from large LWR and coal fired plants for long distance transport to industrial and residential/commercial users is analyzed. Transport of thermal energy as high temperature water is shown to be considerably cheaper than transport as steam, hot oil, or molten salt over a wide temperature range. The delivered heat is competitive with user-generated heat from oil, coal, or electrode boilers at distances well over 50 km when the pipeline operates at high capacity factor. Results indicate that thermal energy storage makes meeting of even very low capacity factor heat demands economic and feasible and gives the utility flexibility to meet coincident electricity and heat demands effectively.

  8. Seasonal thermal energy storage program. Progress report, January 1980-December 1980

    Energy Technology Data Exchange (ETDEWEB)

    Minor, J.E.

    1981-05-01

    The objectives of the Seasonal Thermal Energy Storage (STES) Program is to demonstrate the economic storage and retrieval of 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. Aquifers, ponds, earth, and lakes have potential for seasonal storage. The initial thrust of the STES Program is toward utilization of ground-water systems (aquifers) for thermal energy storage. Program plans for meeting these objectives, the development of demonstration programs, and progress in assessing the technical, economic, legal, and environmental impacts of thermal energy storage are described. (LCL)

  9. The water-energy-climate nexus: Resources and policy outlook for aquifers in Mexico

    Science.gov (United States)

    Scott, Christopher A.

    2011-06-01

    Three interlinked processes drive groundwater balances in diverse regions globally: (1) groundwater-irrigation intensification, (2) electrical energy supply for agriculture, and (3) climatic variability. Mexico's water-energy-climate nexus offers generic lessons because of its water scarcity and institutional reforms followed in other emerging economies. This paper analyzes data for 280 aquifers in Mexico, all registered water users, population projections, 2010-2100 precipitation and temperature projections for A1B and A2 emissions scenarios from 15 general circulation models, and 1999-2009 agricultural electricity use. Under A2 emissions, aquifers with negative balances will increase from 92 to 130 in number between 2010 and 2100, and the national groundwater deficit will increase by 21.3 km3. Under A2 and medium-variant population growth (which peaks midcentury), negative-balance aquifers will increase from 92 to 133, and the national groundwater deficit will increase by 22.4 km3. Agricultural power pricing offers a nexus-based policy tool to address aquifer depletion, an opportunity that was lost with the 2003 reduction in nighttime tariffs. Under A2, medium-variant population, and simulated 2% real annual increases in agricultural power tariffs, negative-balance aquifers will increase from 92 to 111, and the national groundwater deficit will increase by 17.5 km3 between 2010 and 2100. Regulatory and user-based groundwater management initiatives indicate growing awareness of aquifer depletion; however, the long-term outlook points to continued depletion. This raises the need to harness nexus-based policy options, i.e., increasing agricultural power tariffs, eliminating reduced nighttime tariffs, enforcing legislation linking groundwater extraction to power use, and limiting new power connections for groundwater wells.

  10. A heat and dye tracer test for characterizing and modelling heat transfer in an alluvial aquifer

    OpenAIRE

    Klepikova, Maria; Wildemeersch, Samuel; Jamin, Pierre; Orban, Philippe; Hermans, Thomas; Brouyère, Serge; Dassargues, Alain

    2014-01-01

    Using heat as an active tracer is a topic of increasing interest with regards to characterizing shallow aquifers for ATES (Aquifer Thermal Energy Storage) systems. In this study, we investigate the potential interest of coupling simultaneous heat and dye tracer injection tests for characterization of an alluvial aquifer. The study site is located near Liege in the alluvial aquifer of the Meuse River, Belgium. The tracing experiment consisted in simultaneously injecting heated water and a dye ...

  11. Thermal energy storage program description

    Energy Technology Data Exchange (ETDEWEB)

    Reimers, E. [Dept. of Energy, Washington, DC (United States)

    1989-03-01

    The U.S. Department of Energy (DOE) has sponsored applied research, development, and demonstration of technologies aimed at reducing energy consumption and encouraging replacement of premium fuels (notably oil) with renewable or abundant indigenous fuels. One of the technologies identified as being able to contribute to these goals is thermal energy storage (TES). Based on the potential for TES to contribute to the historic mission of the DOE and to address emerging energy issues related to the environment, a program to develop specific TES technologies for diurnal, industrial, and seasonal applications is underway. Currently, the program is directed toward three major application targets: (1) TES development for efficient off-peak building heating and cooling, (2) development of advanced TES building materials, and (3) TES development to reduce industrial energy consumption.

  12. On Pore Dynamics and Calcite Solubility in Carbonaceous Aquifers used in Energy Storage Applications

    Science.gov (United States)

    Tilley, Bs; Brady, Ds; Ueckert, M.; Baumann, T.

    2015-11-01

    Geothermal energy harvesting applications use deep groundwater aquifers to store harvested energy. The impact of this additional energy to the aquifer chemistry is crucial for long-term operation. Gaseous CO2 is added to the injected water to compensate potential precipitates of carbonates and to prevent structural changes to the aquifer. Both of these effects affect the local chemical equilibrium of the aquifer, and we consider a long-wave model of this process for a single axisymmetric pore where gaseous CO2 concentration, temperature, fluid flow and hydrochemistry modify the pore radius in space and time. Substrates are composed of calcite and dolomite, whose composition evolution is part of the full pore problem. During oscillatory flow conditions, concentration levels of the dissolved species can be sufficient to overcome elevated temperature levels and promote pore closure for sufficiently thin pores. We identify the conditions under which this pore closure takes place. Support from the Bavarian State Ministry for the Economy is gratefully acknowledged.

  13. More Efficient Solar Thermal-Energy Receiver

    Science.gov (United States)

    Dustin, M. O.

    1987-01-01

    Thermal stresses and reradiation reduced. Improved design for solar thermal-energy receiver overcomes three major deficiencies of solar dynamic receivers described in literature. Concentrator and receiver part of solar-thermal-energy system. Receiver divided into radiation section and storage section. Concentrated solar radiation falls on boiling ends of heat pipes, which transmit heat to thermal-energy-storage medium. Receiver used in number of applications to produce thermal energy directly for use or to store thermal energy for subsequent use in heat engine.

  14. Short term thermal energy storage

    OpenAIRE

    Abhat, A.

    1980-01-01

    The present paper reviews the problem of short term thermal energy storage for low temperature solar heating applications. The techniques of sensible and latent heat storage are discussed, with particular emphasis on the latter. Requirements for hot water storage subsystems are provided and the importance of stratification in hot water storage tanks is described. Concerning latent heat storage, both material and heat exchanger aspects are considered in detail. The example of a passively opera...

  15. Thermal energy storage flight experiments

    Science.gov (United States)

    Namkoong, D.

    1989-01-01

    Consideration is given to the development of an experimental program to study heat transfer, energy storage, fluid movement, and void location under microgravity. Plans for experimental flight packages containing Thermal Energy Storage (TES) material applicable for advanced solar heat receivers are discussed. Candidate materials for TES include fluoride salts, salt eutectics, silicides, and metals. The development of a three-dimensional computer program to describe TES material behavior undergoing melting and freezing under microgravity is also discussed. The TES experiment concept and plans for ground and flight tests are outlined.

  16. Seasonal sensible thermal energy storage solutions

    Directory of Open Access Journals (Sweden)

    Lavinia Gabriela SOCACIU

    2012-08-01

    Full Text Available The thermal energy storage can be defined as the temporary storage of thermal energy at high or low temperatures. Thermal energy storage is an advances technology for storing thermal energy that can mitigate environmental impacts and facilitate more efficient and clean energy systems. Seasonal thermal energy storage has a longer thermal storage period, generally three or more months. This can contribute significantly to meeting society`s need for heating and cooling. The objectives of thermal energy storage systems are to store solar heat collected in summer for space heating in winter. This concept is not new; it is been used and developed for centuries because is playing an important role in energy conservation and contribute significantly to improving the energy efficiency and reducing the gas emissions to the atmosphere.

  17. Aquifer stability investigations

    Energy Technology Data Exchange (ETDEWEB)

    Allen, R.D.; Doherty, T.J.

    1981-09-01

    The study of compressed air energy storage (CAES) in porous rock reservoirs is carried out within the Reservoir Stability Studies Program at Pacific Northwest Laboratory. The goal of the study is to establish criteria for long-term stability of aquifer CAES reservoirs. These criteria are intended to be guidelines and check lists that utilities and architect-engineering firms may use to evaluate reservoir stability at candidate CAES sites. These criteria will be quantitative where possible, qualitative where necessary, and will provide a focal point for CAES relevant geotechnical knowledge, whether developed within this study or available from petroleum, mining or other geotechnical practices using rock materials. The Reservoir Stability Studies Program had four major activities: a state-of-the-art survey to establish preliminary stability criteria and identify areas requiring research and development; numerical modeling; laboratory testing to provide data for use in numerical models and to investigate fundamental rock mechanics, thermal, fluid, and geochemical response of aquifer materials; and field studies to verify the feasibility of air injection and recovery under CAES conditions in an aquifer, to validate and refine the stability criteria, and to evaluate the accuracy and adequacy of the numerical and experimental methodologies developed in previous work. Three phases of study, including preliminary criteria formulation, numerical model development, and experimental assessment of CAES reservoir materials have been completed. Present activity consists of construction and operation of the aquifer field test, and associated numerical and experimental work in support of that activity. Work is presently planned to be complete by 1983 at the end of the field test. At that time the final stability criteria for aquifers will be issued. Attached here also are preliminary criteria for aquifers.

  18. Improved Calculation of Thermal Fission Energy

    OpenAIRE

    Ma, X. B.; Zhong, W. L.; Wang, L. Z.; Y. X. Chen; Cao, J

    2012-01-01

    Thermal fission energy is one of the basic parameters needed in the calculation of antineutrino flux for reactor neutrino experiments. It is useful to improve the precision of the thermal fission energy calculation for current and future reactor neutrino experiments, which are aimed at more precise determination of neutrino oscillation parameters. In this article, we give new values for thermal fission energies of some common thermal reactor fuel isotopes, with improvements on three aspects. ...

  19. Solar energy thermally powered electrical generating system

    Science.gov (United States)

    Owens, William R. (Inventor)

    1989-01-01

    A thermally powered electrical generating system for use in a space vehicle is disclosed. The rate of storage in a thermal energy storage medium is controlled by varying the rate of generation and dissipation of electrical energy in a thermally powered electrical generating system which is powered from heat stored in the thermal energy storage medium without exceeding a maximum quantity of heat. A control system (10) varies the rate at which electrical energy is generated by the electrical generating system and the rate at which electrical energy is consumed by a variable parasitic electrical load to cause storage of an amount of thermal energy in the thermal energy storage system at the end of a period of insolation which is sufficient to satisfy the scheduled demand for electrical power to be generated during the next period of eclipse. The control system is based upon Kalman filter theory.

  20. Solar energy thermalization and storage device

    Science.gov (United States)

    McClelland, J.F.

    A passive solar thermalization and thermal energy storage assembly which is visually transparent is described. The assembly consists of two substantial parallel, transparent wall members mounted in a rectangular support frame to form a liquid-tight chamber. A semitransparent thermalization plate is located in the chamber, substantially paralled to and about equidistant from the transparent wall members to thermalize solar radiation which is stored in a transparent thermal energy storage liquid which fills the chamber. A number of the devices, as modules, can be stacked together to construct a visually transparent, thermal storage wall for passive solar-heated buildings.

  1. Biogeographic patterns of desert springs in the Great Basin with an emphasis on regional aquifer thermal springs as refugia for vulnerable crenobiotic species

    Science.gov (United States)

    Forrest, M.; Sada, D. W.; Norris, R. D.

    2013-12-01

    The desert springs of the Great Basin Region in western North America provide ideal systems to study biogeographic and evolutionary patterns. In arid regions, springs are biodiversity hotspots because they often provide the sole source of water for the biota within and around them. In the Great Basin, springs provide critical habitat for diverse and extensive crenobiotic flora and fauna comprising over 125 endemic species. These aquatic environments represent island ecosystems surrounded by seas of desert, and researchers have compiled large databases of their biota and chemistry. Consequently, desert springs are excellent systems for biogeographic studies and multivariate statistical analyses of relationships between the chemical and physical characteristics of the springs and the biological communities that they support. The purpose of this study is to elucidate the relationships between the physicochemical characteristics of springs and their biota using multivariate statistical analyses to characterize 1325 springs, including regional aquifer springs, local aquifer cold springs and geothermal springs. The analyses reveal that regional aquifer thermal springs harbor disproportionate numbers of crenobiotic species including endemic gastropods, fishes, and aquatic insects. However, these regional aquifer springs also contain significantly more introduced species than cold and geothermal local aquifer springs. Springs are threatened by anthropogenic impacts including groundwater depletion and pollution, alteration of flow regimes, and the introduction of exotic species. In this study, one of the major factors that distinguished regional aquifer thermal springs from cold and geothermal local aquifer springs was the higher number of introduced species found in regional aquifer springs. This may be due to the influences of the same physicochemical characteristics that allow regional aquifer springs to serve as refugia for endemic species--species that are able to gain

  2. Thermal modeling and optimization of a thermally matched energy harvester

    Science.gov (United States)

    Boughaleb, J.; Arnaud, A.; Cottinet, P. J.; Monfray, S.; Gelenne, P.; Kermel, P.; Quenard, S.; Boeuf, F.; Guyomar, D.; Skotnicki, T.

    2015-08-01

    The interest in energy harvesting devices has grown with the development of wireless sensors requiring small amounts of energy to function. The present article addresses the thermal investigation of a coupled piezoelectric and bimetal-based heat engine. The thermal energy harvester in question converts low-grade heat flows into electrical charges by achieving a two-step conversion mechanism for which the key point is the ability to maintain a significant thermal gradient without any heat sink. Many studies have previously focused on the electrical properties of this innovative device for energy harvesting but until now, no thermal modeling has been able to describe the device specificities or improve its thermal performances. The research reported in this paper focuses on the modeling of the harvester using an equivalent electrical circuit approach. It is shown that the knowledge of the thermal properties inside the device and a good comprehension of its heat exchange with the surrounding play a key role in the optimization procedure. To validate the thermal modeling, finite element analyses as well as experimental measurements on a hot plate were carried out and the techniques were compared. The proposed model provided a practical guideline for improving the generator design to obtain a thermally matched energy harvester that can function over a wide range of hot source temperatures for the same bimetal. A direct application of this study has been implemented on scaled structures to maintain an important temperature difference between the cold surface and the hot reservoir. Using the equations of the thermal model, predictions of the thermal properties were evaluated depending on the scaling factor and solutions for future thermal improvements are presented.

  3. Thermal energy management process experiment

    Science.gov (United States)

    Ollendorf, S.

    1984-01-01

    The thermal energy management processes experiment (TEMP) will demonstrate that through the use of two-phase flow technology, thermal systems can be significantly enhanced by increasing heat transport capabilities at reduced power consumption while operating within narrow temperature limits. It has been noted that such phenomena as excess fluid puddling, priming, stratification, and surface tension effects all tend to mask the performance of two-phase flow systems in a 1-g field. The flight experiment approach would be to attack the experiment to an appropriate mounting surface with a 15 to 20 meter effective length and provide a heat input and output station in the form of heaters and a radiator. Using environmental data, the size, location, and orientation of the experiment can be optimized. The approach would be to provide a self-contained panel and mount it to the STEP through a frame. A small electronics package would be developed to interface with the STEP avionics for command and data handling. During the flight, heaters on the evaporator will be exercised to determine performance. Flight data will be evaluated against the ground tests to determine any anomalous behavior.

  4. Numerical Simulation of Thermal-Hydrological-Mechanical-Chemical Processes during CO2 Geo-sequestration in Saline Aquifer

    Science.gov (United States)

    zhang, R.; Winterfeld, P.; Yin, X.; Wu, Y.

    2013-12-01

    The significance of thermal-hydrologic-mechanical-chemical (THMC) processes is well recognized in the operation of CO2 geo-sequestration. Geomechanical and geochemical effects may significantly change aqueous phase composition, porosity and permeability of the formation, and in turn flow and transport. The TOUGHREACT simulator (Xu et al., 2004) has the capability to quantitatively simulate multiphase fluid flow, solute transport and geochemical reactions during CO2 sequestration in saline aquifers using a sequential coupling. Using a mean stress formulation, stresses, displacements, and rock deformations due to fluid injection have been simulated by the recently developed TOUGH2-CSM (Winterfeld and Wu, 2011) to account for the geomechanical effects in CO2 sequestration in saline aquifers. Based on these previously developed numerical simulators: TOUGH-ECO2N (Pruess, 2005), TOUGHREACT, and TOUGH2-CSM, we present general mathematical formulations of the THMC processes. Two coupled computational frameworks (sequentially coupled procedure and fully coupled procedure) are developed to simulate reactive, multiphase transport of CO2 in saline aquifer with thermal and geomechanical effects; both of them model (1) fluid and heat flow, and solute transport in the aqueous phase within a three-phase mixture, (2) stresses and displacements related to the mean stress, (3) non-isothermal effects on fluid properties and reaction processes, and (4) chemical equilibrium and kinetics of fluid-rock and gas-rock interactions. A set of partial differential equations is formulated to represent the physical, mechanical and chemical processes. The accuracy of the THMC models is demonstrated using four examples with analytical solutions: (1) 1D reactive transport under chemical equilibrium conditions, (2) 1D reactive transport with chemical kinetics, (3) 1D heat conduction, and (4) 1D consolidation. Finally, the developed reactive transport models with general chemical compositions are

  5. Thermal energy storage apparatus, controllers and thermal energy storage control methods

    Science.gov (United States)

    Hammerstrom, Donald J.

    2016-05-03

    Thermal energy storage apparatus, controllers and thermal energy storage control methods are described. According to one aspect, a thermal energy storage apparatus controller includes processing circuitry configured to access first information which is indicative of surpluses and deficiencies of electrical energy upon an electrical power system at a plurality of moments in time, access second information which is indicative of temperature of a thermal energy storage medium at a plurality of moments in time, and use the first and second information to control an amount of electrical energy which is utilized by a heating element to heat the thermal energy storage medium at a plurality of moments in time.

  6. Potential energy savings and thermal comfort

    DEFF Research Database (Denmark)

    Jensen, Karsten Ingerslev; Rudbeck, Claus Christian; Schultz, Jørgen Munthe

    1996-01-01

    The simulation results on the energy saving potential and influence on indoor thermal comfort by replacement of common windows with aerogel windows as well as commercial low-energy windows are described and analysed.......The simulation results on the energy saving potential and influence on indoor thermal comfort by replacement of common windows with aerogel windows as well as commercial low-energy windows are described and analysed....

  7. Geological factors affecting the chemical characteristics of the thermal waters of the carbonate karstified aquifers of Northern Vietnam

    Directory of Open Access Journals (Sweden)

    C. Drogue

    2000-01-01

    Full Text Available In northern Vietnam, exposed carbonate rock formations cover an area of more than 50,000 km2 .Their accumulated thickness from the Cambrian to the Triassic is in some places as much as 3000 m. Numerous thermal waters (springs and wells occur in these strongly karstified carbonate massifs. This is the result of significant ancient and present orogenic activity, as the region demonstrates by its strong seismic activity. These karstic formations are water-bearing and strongly recharged by rainfall of between 1600 mm and 2000 mm per year in 90% of the area concerned. In view of the average annual air temperatures (17°C-25°C according to the region, 23 sample springs or wells were chosen with water temperatures of between 29°C and 68°C. Hydrochemical characteristics of these thermal waters emerging in different carbonate-rock units were examined by chemical analyses of major ions. In this large region, thermal waters are divided into four hydrochemical types: the Na-Cl type resulting from the intrusion of sea water for distances of up to several kilometres inland and depths of 1000 m, the Ca-SO4 type, probably resulting from the leaching of deposits of metallic sulphides that are widely distributed in these carbonate-rock units, and finally the Ca-HCO3 and Mg-HCO3 types which are chemically similar to fresh karstic waters in limestones and dolostones. The occurrence of these thermal groundwaters as well as their chemical characteristics seem to indicate the existence of large-scale deepseated groundwater flow systems in the karstic aquifers. Keywords: Vietnam; thermal waters; karst; hydrochemistry

  8. The Importance of Thermal Dispersivity in Predicting Water Movement Through Coarse-grained Alluvial Aquifers by Analysis of Seasonal Temperature Signals

    Science.gov (United States)

    Amerson, B. E.; Poole, G. C.; O'Daniel, S. J.; Lambert, M. B.

    2014-12-01

    In the last decade, there has been a surge in research on the use of time-varying temperature records (e.g. diel temperature) to estimate seepage velocity of water across stream channel boundaries into or out of the hyporheic zone. The hallmark of this research is the use temperature signals measured over length scales of a few meters to determine the properties of interest. Application of the methods at the river reach scale (e.g. tens of meters) using seasonal temperatures signals has not been explored. For instance, research in the Umatilla River basin in north central Oregon USA shows that seasonal temperature records from the hyporheic zone exhibit characteristic phase lagging and amplitude damping that closely matches similar characteristics observed in diel temperature signals typically used to estimate streambed seepage velocity. We demonstrate that at these larger scales, aquifer thermal dynamics are controlled by mechanical dispersion rather than thermal conduction. The trade-off between conduction and dispersion is apparent in plots of the ratio (r) of dispersive to conductive forces verses the thermal Peclet number (Pe). Plotting a range of analytical solutions for r and Pe over a range of hydraulic conductivities and dispersivities allows visual comparison of of their relative position in a spreading-transport domain. We show that when dispersivity and velocity are large, dispersion governs both spreading and transport processes of thermal energy in contrast to conduction. This finding is analogous to well-known findings from solute transport theory that show a trade off from conductive forces to dispersive forces as both scale and velocity increase. Furthermore, we demonstrate that when reasonable values for dispersion are not included in analytical temperature solutions using seasonal temperature records, unrealistic minimal amplitude damping results. Our results suggest that incorporating dispersion into analytical and modeling solutions is key to

  9. Phase Change Materials for Thermal Energy Storage

    OpenAIRE

    Stiebra, L; Cabulis, U; Knite, M

    2014-01-01

    Phase change materials (PCMs) for thermal energy storage (TES) have become an important subject of research in recent years. Using PCMs for thermal energy storage provides a solution to increase the efficiency of the storage and use of energy in many domestic and industrial sectors. Phase change TES systems offer a number of advantages over other systems (e.g. chemical storage systems): particularly small temperature distance between the storage and retrieval cycles, small unit sizes and lo...

  10. The Romanian perspective on geothermal energy resources. The chemistry of the geothermal waters from Oradea Triassic aquifer

    Directory of Open Access Journals (Sweden)

    Ruxandra M. Petrescu-Mag

    2009-01-01

    Full Text Available In 2008, the European Commission put forward a proposal for a new directive (COM (200830 on renewable energies to replace the existing measures adopted in 2001. According to the proposal, each member state should increase its share of renewable energies - such as solar, wind or hydro - in an effort to boost the EU's share from 8.5% today to 20% by 2020. According to Cohuţ & Bendea (2000 in Romania are over 200 wells drilled to depths between 800 and 3500 m that encountered geothermalresources at temperatures from 40 to 120 °C. These wells have a total thermal capacity of about 480 Mwt. The Oradea aquifer was identified between 1963-1964 by the drills 4005 and 4006. To establish the content of the major elements of the geothermal waters from the production wells from Oradea, the geothermal fluids were sampled and analyzed during six months (since October 2007 to March 2008, by using ion chromatographic (IC method. In this period of the year, the geothermal installations are used at the maximum capacity.

  11. Graphene Thermal Properties: Applications in Thermal Management and Energy Storage

    Directory of Open Access Journals (Sweden)

    Jackie D. Renteria

    2014-11-01

    Full Text Available We review the thermal properties of graphene, few-layer graphene and graphene nanoribbons, and discuss practical applications of graphene in thermal management and energy storage. The first part of the review describes the state-of-the-art in the graphene thermal field focusing on recently reported experimental and theoretical data for heat conduction in graphene and graphene nanoribbons. The effects of the sample size, shape, quality, strain distribution, isotope composition, and point-defect concentration are included in the summary. The second part of the review outlines thermal properties of graphene-enhanced phase change materials used in energy storage. It is shown that the use of liquid-phase-exfoliated graphene as filler material in phase change materials is promising for thermal management of high-power-density battery parks. The reported experimental and modeling results indicate that graphene has the potential to outperform metal nanoparticles, carbon nanotubes, and other carbon allotropes as filler in thermal management materials.

  12. Design of a high temperature subsurface thermal energy storage system

    Science.gov (United States)

    Zheng, Qi

    Solar thermal energy is taking up increasing proportions of future power generation worldwide. Thermal energy storage technology is a key method for compensating for the inherent intermittency of solar resources and solving the time mismatch between solar energy supply and electricity demand. However, there is currently no cost-effective high-capacity compact storage technology available (Bakker et al., 2008). The goal of this work is to propose a high temperature subsurface thermal energy storage (HSTES) technology and demonstrate its potential energy storage capability by developing a solar-HSTES-electricity generation system. In this work, main elements of the proposed system and their related state-of-art technologies are reviewed. A conceptual model is built to illustrate the concept, design, operating procedure and application of such a system. A numerical base model is built within the TOUGH2-EOS1 multiphase flow simulator for the evaluation of system performance. Additional models are constructed and simulations are done to identify the effect of different operational and geological influential factors on the system performance. Our work shows that when the base model is run with ten years operation of alternate injection and production processes - each for a month - with a thermal power input of 10.85 MW, about 83% of the injected thermal energy could be recovered within each working cycle from a stabilized HSTES system. After the final conversion into electrical energy, a relative (compared with the direct use of hot water) electricity generation efficiency of 73% is obtained. In a typical daily storage scenario, the simulated thermal storage efficiency could exceed 78% and the relative electricity generation efficiency is over 66% in the long run. In a seasonal storage scenario, these two efficiencies reach 69% and 53% respectively by the end of the simulation period of 10 years. Additional simulations reveal a thinner storage aquifer with a higher

  13. Hydrochemical properties of deep carbonate aquifers in the SW German Molasse basin

    OpenAIRE

    Stober, I.; Bucher, K

    2015-01-01

    Background The Upper Jurassic (Malm) limestone and the Middle Triassic Muschelkalk limestone 18 are the major thermal aquifers in the southwest German alpine foreland. The aquifers 19 are of interest for production of geothermal energy and for balneological purposes. Methods Hydrochemical data from several hundred wells within two deep limestone aquifers in the Molasse basin of SW Germany have been compiled, examined, validated, and analyzed with the aim to characterize the fluids...

  14. Energy efficient thermal management of data centers

    CERN Document Server

    Kumar, Pramod

    2012-01-01

    Energy Efficient Thermal Management of Data Centers examines energy flow in today's data centers. Particular focus is given to the state-of-the-art thermal management and thermal design approaches now being implemented across the multiple length scales involved. The impact of future trends in information technology hardware, and emerging software paradigms such as cloud computing and virtualization, on thermal management are also addressed. The book explores computational and experimental characterization approaches for determining temperature and air flow patterns within data centers. Thermodynamic analyses using the second law to improve energy efficiency are introduced and used in proposing improvements in cooling methodologies. Reduced-order modeling and robust multi-objective design of next generation data centers are discussed. This book also: Provides in-depth treatment of energy efficiency ideas based on  fundamental heat transfer, fluid mechanics, thermodynamics, controls, and computer science Focus...

  15. TES (Thermal Energy Storage) Video News Release

    Science.gov (United States)

    1994-01-01

    TES is an in-space technology experiment that flew on STS-62. Its intent is to investigate the behavior of two different thermal energy storage materials as they undergo repeated melting and freezing in the microgravity environment.

  16. Enhancing radiative energy transfer through thermal extraction

    Science.gov (United States)

    Tan, Yixuan; Liu, Baoan; Shen, Sheng; Yu, Zongfu

    2016-06-01

    Thermal radiation plays an increasingly important role in many emerging energy technologies, such as thermophotovoltaics, passive radiative cooling and wearable cooling clothes [1]. One of the fundamental constraints in thermal radiation is the Stefan-Boltzmann law, which limits the maximum power of far-field radiation to P0 = σT4S, where σ is the Boltzmann constant, S and T are the area and the temperature of the emitter, respectively (Fig. 1a). In order to overcome this limit, it has been shown that near-field radiations could have an energy density that is orders of magnitude greater than the Stefan-Boltzmann law [2-7]. Unfortunately, such near-field radiation transfer is spatially confined and cannot carry radiative heat to the far field. Recently, a new concept of thermal extraction was proposed [8] to enhance far-field thermal emission, which, conceptually, operates on a principle similar to oil immersion lenses and light extraction in light-emitting diodes using solid immersion lens to increase light output [62].Thermal extraction allows a blackbody to radiate more energy to the far field than the apparent limit of the Stefan-Boltzmann law without breaking the second law of thermodynamics. Thermal extraction works by using a specially designed thermal extractor to convert and guide the near-field energy to the far field, as shown in Fig. 1b. The same blackbody as shown in Fig. 1a is placed closely below the thermal extractor with a spacing smaller than the thermal wavelength. The near-field coupling transfers radiative energy with a density greater than σT4. The thermal extractor, made from transparent and high-index or structured materials, does not emit or absorb any radiation. It transforms the near-field energy and sends it toward the far field. As a result, the total amount of far-field radiative heat dissipated by the same blackbody is greatly enhanced above SσT4, where S is the area of the emitter. This paper will review the progress in thermal

  17. Recycling of wasted energy : thermal to electrical energy conversion

    OpenAIRE

    Lim, Hyuck

    2011-01-01

    Harvesting useful electric energy from ambient thermal gradients and/or temperature fluctuations is immensely important. For many years, a number of direct and indirect thermal-to-electrical energy conversion technologies have been developed. Typically, direct energy conversion is achieved by using thermoelectric generators or thermogalvanic cells; indirect energy conversion is achieved by using Organic Rankine Cycle or Sterling Engines. On the one hand, there is a fundamental technical diffi...

  18. Thermal power plant efficiency enhancement with Ocean Thermal Energy Conversion

    International Nuclear Information System (INIS)

    In addition to greenhouse gas emissions, coastal thermal power plants would gain further opposition due to their heat rejection distressing the local ecosystem. Therefore, these plants need to enhance their thermal efficiency while reducing their environmental offense. In this study, a hybrid plant based on the principle of Ocean Thermal Energy Conversion was coupled to a 740 MW coal-fired power plant project located at latitude 28°S where the surface to deepwater temperature difference would not suffice for regular OTEC plants. This paper presents the thermodynamical model to assess the overall efficiency gained by adopting an ammonia Rankine cycle plus a desalinating unit, heated by the power plant condenser discharge and refrigerated by cold deep seawater. The simulation allowed us to optimize a system that would finally enhance the plant power output by 25–37 MW, depending on the season, without added emissions while reducing dramatically the water temperature at discharge and also desalinating up to 5.8 million tons per year. The supplemental equipment was sized and the specific emissions reduction was estimated. We believe that this approach would improve the acceptability of thermal and nuclear power plant projects regardless of the plant location. -- Highlights: • An Ocean Thermal Energy Conversion hybrid plant was designed. • The waste heat of a power plant was delivered as an OTEC heat source. • The effect of size and operating conditions on plant efficiency were studied. • The OTEC implementation in a Chilean thermal power plant was evaluated. • The net efficiency of the thermal power plant was increased by 1.3%

  19. Ocean thermal energy conversion: An overview

    Science.gov (United States)

    1989-11-01

    Ocean thermal energy conversion, or OTEC is a technology that extracts power from the ocean's natural thermal gradient. This technology is being pursued by researchers from many nations; in the United States, OTEC research is funded by the U.S. Department of Energy's Ocean Energy Technology program. The program's goal is to develop the technology so that industry can make a competent assessment of its potential; either as an alternative or as a supplement to conventional energy sources. Federally funded research in components and systems will help OTEC to the threshold of commercialization. An overview of the OTEC technology is provided.

  20. Evaluation of New Thermally Conductive Geopolymer in Thermal Energy Storage

    Science.gov (United States)

    Černý, Matěj; Uhlík, Jan; Nosek, Jaroslav; Lachman, Vladimír; Hladký, Radim; Franěk, Jan; Brož, Milan

    This paper describes an evaluation of a newly developed thermally conductive geopolymer (TCG), consisting of a mixture of sodium silicate and carbon micro-particles. The TCG is intended to be used as a component of high temperature energy storage (HTTES) to improve its thermal diffusivity. Energy storage is crucial for both ecological and economical sustainability. HTTES plays a vital role in solar energy technologies and in waste heat recovery. The most advanced HTTES technologies are based on phase change materials or molten salts, but suffer with economic and technological limitations. Rock or concrete HTTES are cheaper, but they have low thermal conductivity without incorporation of TCG. It was observed that TCG is stable up to 400 °C. The thermal conductivity was measured in range of 20-23 W m-1 K-1. The effect of TCG was tested by heating a granite block with an artificial fissure. One half of the fissure was filled with TCG and the other with ballotini. 28 thermometers, 5 dilatometers and strain sensors were installed on the block. The heat transport experiment was evaluated with COMSOL Multiphysics software.

  1. Integration of thermal energy and seawater desalination

    Energy Technology Data Exchange (ETDEWEB)

    Deng, Runya; Lin, Hu [Institute of Engineering Thermophysics, Chinese Academy of Sciences, Beijing 100080 (China); Graduate School of Chinese Academy of Sciences, Beijing 100039 (China); Xie, Lixin; Liu, Jie [School of Chemical Engineering and technology, Tianjin University, Tianjin 300072 (China); Han, Wei [Institute of Engineering Thermophysics, Chinese Academy of Sciences, Beijing 100080 (China)

    2010-11-15

    Energy and freshwater shortage are the bottlenecks restricting China's economic development. The integration of energy utilization system and seawater desalination is considered as an innovative technology enabling efficient simultaneous use of middle or low temperature thermal energy and supply freshwater. Three feasible approaches to integrate seawater desalination with energy utilization system are presented in this paper, including combinations of the desalination process with a Combined Cooling Heating and Power system (CCHP), a power plant, or a solar thermal utilization system. In addition, the feasibility and advantages of a seawater desalination system combined with a power plant are described. The findings indicate that combining seawater desalination with industrial processes is a feasible and promising way to solve the problems of the lack of freshwater and low efficient use of low temperature thermal energy in coastland areas. (author)

  2. Thermodynamic analyses and assessments of various thermal energy storage systems for buildings

    International Nuclear Information System (INIS)

    Highlights: ► Proposing a novel latent (PCM), thermochemical and sensible (aquifer) TES combination for building heating. ► Performing comprehensive environmental, energy, exergy and sustainability analyses. ► Investigating the effect of varying dead state temperatures on the TESs. - Abstract: In this study, energetic, exergetic, environmental and sustainability analyses and their assessments are carried out for latent, thermochemical and sensible thermal energy storage (TES) systems for phase change material (PCM) supported building applications under varying environment (surrounding) temperatures. The present system consists of a floor heating system, System-I, System-II and System-III. The floor heating system stays at the building floor supported with a floor heating unit and pump. The System-I includes a latent TES system and a fan. The latent TES system is comprised of a PCM supported building envelope, in which from outside to inside; glass, transparent insulation material, PCM, air channel and insulation material are placed, respectively. Furthermore, System-II mainly has a solar-thermochemical TES while there are an aquifer TES and a heat pump in System-III. Among the TESs, the hot and cold wells of the aquifer TES have maximum exergetic efficiency values of 88.782% and 69.607% at 8 °C dead state temperature, respectively. According to the energy efficiency aspects of TESs, the discharging processes of the latent TES and the hot well of the aquifer TES possess the minimum and maximum values of 5.782% and 94.118% at 8 °C dead state temperature, respectively. Also, the fan used with the latent TES is the most environmentally-benign system component among the devices. Furthermore, the most sustainable TES is found for the aquifer TES while the worst sustainable system is the latent TES.

  3. Influence of Groundwater on Measurements of Thermal Properties in Fractured Aquifers

    OpenAIRE

    Liebel, Heiko T.

    2012-01-01

    Shallow boreholes equipped with borehole heat exchangers (BHE) connected to ground-coupled heat pumps are used for the heating and cooling of buildings. Accurate estimates of ground properties are essential to properly dimension a ground-coupled heat pump system. For small projects, the ground properties are assumed for different rock types. In large projects, thermal response tests (TRT) are carried out to estimate the actual properties.Convection and groundwater flow affect the TRT results ...

  4. Thermal Energy Storage Flight Experiment in Microgravity

    Science.gov (United States)

    Namkoong, David

    1992-01-01

    The Thermal Energy Storage Flight Experiment was designed to characterize void shape and location in LiF-based phase change materials in different energy storage configurations representative of advanced solar dynamic systems. Experiment goals and payload design are described in outline and graphic form.

  5. French work on ocean thermal energy conversion

    Science.gov (United States)

    Marchand, P.

    The ocean is discussed as a world-wide potential source of renewable energy, with special attention given to the 'deposit' of ocean thermal energy, which is determined by the temperature difference existing between surface water and that at a depth of 1000 m. A brief history of work done in France is presented, and mention is made of the work of d'Arsonval (1881), Claude and Boucherot (1926), and of projects, such as those at Abidjan and Guadeloupe. Attention is given to the French ocean thermal energy sites, to the Empain-Schneider closed-cycle studies, and the open-cycle floating ocean thermal energy station, with a discussion of thermodynamic considerations and cold water pipes. Problems and prospects are reviewed.

  6. Romania needs a strategy for thermal energy

    Directory of Open Access Journals (Sweden)

    Leca Aureliu

    2015-06-01

    Full Text Available The energy sector in Romania consists of three sub-sectors: electricity, natural gas and heat. Among these, the sub-sector of thermal energy is in the most precarious situation because it has been neglected for a long time. This sub-sector is particularly important both due to the amount of final heat consumption (of over 50% of final energy consumption, and to the fact that it has a direct negative effect on the population, industry and services. This paper presents the main directions for developing a modern strategy of the thermal energy sub-sector, which would fit into Romania’s Energy Strategy that is still in preparation This is based on the author’s 50 years of experience in this field that includes knowledge about the processes and the equipment of thermal energy, expertise in the management and restructuring of energy companies and also knowledge of the specific legislation. It is therefore recommended, following the European regulations and practices, the promotion and upgrading of district heating systems using efficient cogeneration, using trigeneration in Romania, modernizing buildings in terms of energy use, using of renewable energy sources for heating, especially biomass, and modernizing the energy consumption of rural settlements.

  7. Phase-Change Thermal Energy Storage

    Science.gov (United States)

    1989-11-01

    The goal of this program is to advance the engineering and scientific understanding of solar thermal technology and to establish the technology base from which private industry can develop solar thermal power production options for introduction into the competitive energy market. Solar thermal technology concentrates the solar flux using tracking mirrors or lenses onto a receiver where the solar energy is absorbed as heat and converted into electricity or incorporated into products as process heat. The two primary solar thermal technologies, central receivers and distributed receivers, employ various point and line-focus optics to concentrate sunlight. Current central receiver systems use fields of heliostats (two-axes tracking mirrors) to focus the sun's radiant energy onto a single, tower-mounted receiver. Point focus concentrators up to 17 meters in diameter track the sun in two axes and use parabolic dish mirrors or Fresnel lenses to focus radiant energy onto a receiver. Troughs and bowls are line-focus tracking reflectors that concentrate sunlight onto receiver tubes along their focal lines. Concentrating collector modules can be used alone or in a multimodule system. The concentrated radiant energy absorbed by the solar thermal receiver is transported to the conversion process by a circulating working fluid. Receiver temperatures range from 100 C in low-temperature troughs to over 1500 C in dish and central receiver systems.

  8. Solar Thermal Energy; Energia Solar Termica

    Energy Technology Data Exchange (ETDEWEB)

    Perez-Martinez, M.; Cuesta-Santianes, M. J.; Cabrera Jimenez, J. A.

    2008-07-01

    Approximately, 50 % of worldwide primary energy consumption is done in the form of heat in applications with a temperature lower than 250 degree centigree (low-medium temperature heat). These data clearly demonstrate the great potential of solar thermal energy to substitute conventional fossil fuels, which are becoming more expensive and are responsible for global warming. Low-medium temperature solar thermal energy is mainly used to obtain domestic hot water and provide space heating. Active solar thermal systems are those related to the use of solar thermal collectors. This study is dealing with low temperature solar thermal applications, mainly focusing on active solar thermal systems. This kind of systems has been extensively growing worldwide during the last years. At the end of 2006, the collector capacity in operation worldwide equalled 127.8 GWth. The technology is considered to be already developed and actions should be aimed at favouring a greater market penetration: diffusion, financial support, regulations establishment, etc. China and USA are the leading countries with a technology based on evacuated tube collectors and unglazed collectors, respectively. The rest of the world markets are dominated by the flat glazed collectors technology. (Author) 15 refs.

  9. Energy conservation through thermally insulated structures

    International Nuclear Information System (INIS)

    The propose of this paper is to explicate its title through investigating the different available thermal insulating materials and the various techniques of application, as practiced in Jordan, in particular, and as practiced in many parts of the world in general, which will satisfy Jordanian standards in terms of heat transmittance and thermal comfort. A brief comparison with international standards will shed some light on the stringent measures enforced in the developed world and on our striving aspirations to keep pace. The paper consists of four main parts, pseudoally divided. The first part will deal with the mechanism of heat loss and heat gain in structures during summer and winter. It will also explain the Time-lag phenomenon which is vital for providing thermal comfort inside the dwellings. The second part will evaluate the damages induced by the temperature gradients on the different elements of the structure, particularly next to exterior opening. The paper will also demonstrate the damages induced by water condensation and fungus growth on the internal surfaces of the structure and within its skeleton. A correlation between condensation and thermal insulation will be established. The third part of the paper will evaluate the different available thermal insulating materials and the application techniques which will satisfy the needs for thermal insulating and thermal comfort at the least cost possible. The criteria of an economical design shall be established. As a conclusion, the paper infers answers to the following different criteria discussed throughout the different parts of the paper. The main theme of questions can be summarized as follows: 1)How energy conservation is possible due to thermal insulation? 2)The feasibility of investing in thermal insulation? 3)Is thermal comfort and a healthy atmosphere possible inside the dwellings during all season! What are the conditions necessary to sustain them? 4)What environmental impacts can exist due to

  10. Description of the behavior of an aquifer by using continuous radon monitoring in a thermal spa.

    Science.gov (United States)

    Sainz, Carlos; Rábago, Daniel; Fuente, Ismael; Celaya, Santiago; Quindós, Luis Santiago

    2016-02-01

    Radon ((222)Rn) levels in air and water have been analyzed continuously for almost a year in Las Caldas de Besaya thermal spa, north Spain. Radon is a naturally occurring noble gas from the decay of radium ((226)Ra) both constituents of radioactive uranium 238 series. It has been recognized as a lung carcinogen by the World Health Organization (WHO) and International Agency for Research on Cancer (IARC). Furthermore the Royal Decree R.D 1439/2010 of November, 2010 establishes the obligation to study occupational activities where workers and, where appropriate, members of the public are exposed to inhalation of radon in workplaces such as spas. Together with radon measures several physico-chemical parameters were obtained such as pH, redox potential, electrical conductivity and air and water temperature. The devices used for the study of the temporal evolution of radon concentration have been the RTM 2100, the Radon Scout and gamma spectrometry was complementarily used to determine the transfer factor of the silicone tubes in the experimental device. Radon concentrations obtained in water and air of the spa are high, with an average of 660 Bq/l and 2900 Bq/m(3) respectively, where water is the main source of radon in the air. Radiation dose for workers and public was estimated from these levels of radon. The data showed that the thermal processes can control the behavior of radon which can be also influenced by various physical and chemical parameters such as pH and redox potential. PMID:26599146

  11. Biodegradation of cis-1,2-Dichloroethene in Simulated Underground Thermal Energy Storage Systems.

    Science.gov (United States)

    Ni, Zhuobiao; van Gaans, Pauline; Smit, Martijn; Rijnaarts, Huub; Grotenhuis, Tim

    2015-11-17

    Underground thermal energy storage (UTES) use has showed a sharp rise in numbers in the last decades, with aquifer thermal energy storage (ATES) and borehole thermal energy storage (BTES) most widely used. In many urban areas with contaminated aquifers, there exists a desire for sustainable heating and cooling with UTES and a need for remediation. We investigated the potential synergy between UTES and bioremediation with batch experiments to simulate the effects of changing temperature and liquid exchange that occur in ATES systems, and of only temperature change occurring in BTES systems on cis-DCE reductive dechlorination. Compared to the natural situation (NS) at a constant temperature of 10 °C, both UTES systems with 25/5 °C for warm and cold well performed significantly better in cis-DCE (cis-1,2-dichloroethene) removal. The overall removal efficiency under mimicked ATES and BTES conditions were respectively 13 and 8.6 times higher than in NS. Inoculation with Dehalococcoides revealed that their initial presence is a determining factor for the dechlorination process. Temperature was the dominating factor when Dehalococcoides abundance was sufficient. Stimulated biodegradation was shown to be most effective in the mimicked ATES warm well because of the combined effect of suitable temperature, sustaining biomass growth, and regular cis-DCE supply. PMID:26503690

  12. Simulation of thermocline thermal energy storage system using C

    OpenAIRE

    Meseret Tesfay; Meyyappan Venkatesan

    2013-01-01

    Solar thermal power generation is a modern technology, which has already shown feasible results in the production of electricity. Thermal energy storage (TES) is a crucial element in solar energy applications, which includes the increase of building thermal capacity, solar water heating systems for domestic use, and Concentrated Solar Thermal power plants for electricity generation. Economic, efficient and reliable thermal energy storage systems are a key need of solar thermal power plants, i...

  13. Ocean thermal energy conversion: Materials issues

    Science.gov (United States)

    Darby, J. B., Jr.

    The Ocean thermal Energy Conversion (OTEC) Program, in the Ocean Energy Technology Division of the U.S. Department of Energy, is concerned with the development of options that can be utilized to extract and distribute significant amounts of energy from the ocean. The biofouling control and materials portion of the program is concerned with the development of effective and environmentally acceptable methods to minimize biofouling and corrosion in high thermal conductivity materials suitable for use in heat exchangers and condensers. The mechanical and chemical techniques employed for biofouling control are reviewed and the recent success with chlorination is presented. The corrosion of aluminum alloys, copper alloys, stainless steel, stainless alloys, and titanium in near-surface warm and deep cold water is reviewed with emphasis on aluminum alloys. The major materials issues are reviewed with emphasis on lifetime and cost.

  14. Thermal Insulation Strips Conserve Energy

    Science.gov (United States)

    2009-01-01

    Launching the space shuttle involves an interesting paradox: While the temperatures inside the shuttle s main engines climb higher than 6,000 F hot enough to boil iron for fuel, the engines use liquid hydrogen, the second coldest liquid on Earth after liquid helium. Maintained below 20 K (-423 F), the liquid hydrogen is contained in the shuttle s rust-colored external tank. The external tank also contains liquid oxygen (kept below a somewhat less chilly 90 K or -297 F) that combines with the hydrogen to create an explosive mixture that along with the shuttle s two, powdered aluminum-fueled solid rocket boosters allows the shuttle to escape Earth s gravity. The cryogenic temperatures of the main engines liquid fuel can cause ice, frost, or liquefied air to build up on the external tank and other parts of the numerous launch fueling systems, posing a possible debris risk when the ice breaks off during launch and causing difficulties in the transfer and control of these cryogenic liquid propellants. Keeping the fuel at the necessary ultra-cold temperatures while minimizing ice buildup and other safety hazards, as well as reducing the operational maintenance costs, has required NASA to explore innovative ways for providing superior thermal insulation systems. To address the challenge, the Agency turned to an insulating technology so effective that, even though it is mostly air, a thin sheet can prevent a blowtorch from igniting a match. Aerogels were invented in 1931 and demonstrate properties that make them the most extraordinary insulating materials known; a 1-inch-thick piece of aerogel provides the same insulation as layering 15 panes of glass with air pockets in between. Derived from silica, aluminum oxide, or carbon gels using a supercritical drying process - resulting in a composition of almost 99-percent air - aerogels are the world s lightest solid (among 15 other titles they hold in the Guinness World Records), can float indefinitely on water if treated to be

  15. Plasma thermal energy transport: theory and experiments

    International Nuclear Information System (INIS)

    Experiments on the transport across the magnetic field of electron thermal energy are reviewed (Alcator, Frascati Torus). In order to explain the experimental results, a transport model is described that reconfirmed the need to have an expression for the local diffusion coefficient with a negative exponent of the electron temperature

  16. Determination of major and minor constituents in anoxic thermal brines of deep sandstone aquifers in Northern Germany

    OpenAIRE

    Michael Kühn; C. Niewöhner; M. Isenbeck-Schröter; Hans-Martin Schulz;  

    1998-01-01

    The common process of low energy geothermal exploitation is the doublet of production- and reinjection borehole. The quality of water reinjected into a elastic reservoir is essential for the reliability of an injection well. In order to estimate precipitation reactions it is necessary to obtain extensive reliable analysis data of the water for the use of thermodynamic modelling. For thermal anoxic brines, the analysis of major and especially minor ion content is difficult because of matrix ef...

  17. Recycling of Wasted Energy: Thermal to Electrical Energy Conversion

    Science.gov (United States)

    Lim, Hyuck

    Harvesting useful electric energy from ambient thermal gradients and/or temperature fluctuations is immensely important. For many years, a number of direct and indirect thermal-to-electrical energy conversion technologies have been developed. Typically, direct energy conversion is achieved by using thermoelectric generators or thermogalvanic cells; indirect energy conversion is achieved by using Organic Rankine Cycle or Sterling Engines. On the one hand, there is a fundamental technical difficulty, thermal shorting, that limits the energy conversion efficiency of direct thermoelectric energy conversion methods. While extensive study has been conducted in this area, currently the portion of thermal energy that can be converted to electricity is still small. On the other hand, the indirect energy conversion systems tend to be complicated and expensive. Thus, existing energy harvesting technologies are less economically competitive compared with the grid power. To develop advanced energy harvesting systems, a novel concept using nanoporous materials is investigated. Nanoporous materials have been widely used as advanced absorbents. Because of their ultra-large surface areas (100--2000 m2/g), they can adsorb a large amount of ions when they are immersed in electrolyte solutions. The ion adsorption capacity is thermally dependent. If two nanoporous electrodes are placed at different temperatures, they adsorb different amounts of ions, generating a net output voltage. The thermally driven ion motion causes a transient current, which can be reactivated through temperature fluctuation or internal grounding. The two electrodes are isolated; that is, the direct heat loss between them is minimized. Our experimental data have shown encouraging results: the output voltage and the energy conversion efficiency are higher than that of conventional thermoelectric materials by orders of magnitude. Our study will not only lead to the development of high-performance thermal energy

  18. Development of thermal energy storage concrete

    Energy Technology Data Exchange (ETDEWEB)

    Dong Zhang; Jianmin Zhou; Keru Wa [Tongji Univ., Shanghai (China). State Key Lab. of Concrete Materials Research; Zongjin Li [Hong Kong Univ. of Science and Technology, Kowloon (China). Dept. of Civil Engineering

    2004-06-01

    In this paper, a two-step procedure to produce thermal energy storage concrete (TESC) is described. At the first step, thermal energy storage aggregates (TESAs) were made from porous aggregates absorbing phase changing materials (PCMs). At the second step, TESC was produced with a normal mixing method and using TESAs. An adequate amount of PCM can be incorporated into concrete by the two-step procedure. It can be seen experimentally that the energy storage capacity of the TESC was comparable with that of a commercially available PCM. The experimental results showed that the geometrical features of the porous structure of the aggregates had significant effect on their absorbing ability of the PCM. Aggregates with large pore connectivity factor and transport tunnel in boundary part can absorb more PCM. It was also found that the phase changing behavior was affected by the volume fraction of PCM in concrete. (Author)

  19. Low temperature thermal-energy storage

    Energy Technology Data Exchange (ETDEWEB)

    Segaser, C.S.; Christian, J.E.

    1979-03-01

    This report evaluates currently available techniques and estimated costs of low temperature thermal energy storage (TES) devices applicable to Integrated Community Energy Systems (ICES) installations serving communities ranging in size from approximately 3000 (characterized by an electrical load requirement of 2 MWe) to about 100,000 population (characterized by an electrical load requirement of 100 MWe). Thermal energy in the form of either hotness or coldness can be stored in a variety of media as sensible heat by virtue of a change in temperature of the material, or as latent heat of fusion in which the material changes from the liquid phase to the solid phase at essentially a constant temperature. Both types of material are considered for TES in ICES applications.

  20. Alluvial Aquifer

    Data.gov (United States)

    Kansas Data Access and Support Center — This coverage shows the extents of the alluvial aquifers in Kansas. The alluvial aquifers consist of unconsolidated Quaternary alluvium and contiguous terrace...

  1. Romania needs a strategy for thermal energy

    OpenAIRE

    Leca Aureliu

    2015-01-01

    The energy sector in Romania consists of three sub-sectors: electricity, natural gas and heat. Among these, the sub-sector of thermal energy is in the most precarious situation because it has been neglected for a long time. This sub-sector is particularly important both due to the amount of final heat consumption (of over 50% of final energy consumption), and to the fact that it has a direct negative effect on the population, industry and services. This paper presents the main directions for ...

  2. A thermal energy storage process for large scale electric applications

    OpenAIRE

    Desrues, T; Ruer, J; Marty, P.; Fourmigué, JF

    2009-01-01

    Abstract A new type of thermal energy storage process for large scale electric applications is presented, based on a high temperature heat pump cycle which transforms electrical energy into thermal energy and stores it inside two large regenerators, followed by a thermal engine cycle which transforms the stored thermal energy back into electrical energy. The storage principle is described, and its thermodynamic cycle is analyzed, leading to the theoretical efficiency of the storage...

  3. Improvements to thermal plants for generating energy

    International Nuclear Information System (INIS)

    Said invention relates to a procedure for superheating steam intended for steam cycled thermal plants of energy production, and particularly nuclear power plants. Said procedure combines two different working modes. According to the first working mode, the live steam is taken from the steam generator, mechanically compressed and the heat is partly transferred to the working fluid. According to the second working mode the heat is taken from an auxiliary fluid heated by an independent thermal source, distinct from the principal thermal source of the plant and this heat is partly transferred to the working fluid. A combination of both working modes enables the superheating of the working fluid to be obtained before it inflows the turbine and/or between two stages of said turbine

  4. Composite Materials for Thermal Energy Storage: Enhancing Performance through Microstructures

    OpenAIRE

    Ge, Zhiwei; YE, Feng; Ding, Yulong

    2014-01-01

    Chemical incompatibility and low thermal conductivity issues of molten-salt-based thermal energy storage materials can be addressed by using microstructured composites. Using a eutectic mixture of lithium and sodium carbonates as molten salt, magnesium oxide as supporting material, and graphite as thermal conductivity enhancer, the microstructural development, chemical compatibility, thermal stability, thermal conductivity, and thermal energy storage performance of composite materials are inv...

  5. Thermal Profiling of Residential Energy Use

    Energy Technology Data Exchange (ETDEWEB)

    Albert, A; Rajagopal, R

    2015-03-01

    This work describes a methodology for informing targeted demand-response (DR) and marketing programs that focus on the temperature-sensitive part of residential electricity demand. Our methodology uses data that is becoming readily available at utility companies-hourly energy consumption readings collected from "smart" electricity meters, as well as hourly temperature readings. To decompose individual consumption into a thermal-sensitive part and a base load (non-thermally-sensitive), we propose a model of temperature response that is based on thermal regimes, i.e., unobserved decisions of consumers to use their heating or cooling appliances. We use this model to extract useful benchmarks that compose thermal profiles of individual users, i.e., terse characterizations of the statistics of these users' temperature-sensitive consumption. We present example profiles generated using our model on real consumers, and show its performance on a large sample of residential users. This knowledge may, in turn, inform the DR program by allowing scarce operational and marketing budgets to be spent on the right users-those whose influencing will yield highest energy reductions-at the right time. We show that such segmentation and targeting of users may offer savings exceeding 100% of a random strategy.

  6. Solar thermal energy conversion to electrical power

    International Nuclear Information System (INIS)

    The conversion of solar energy to electricity currently relies primarily on the photovoltaic effect in which photon bombardment of photovoltaic cells drives an electromotive force within the material. Alternatively, recent studies have investigated the potential of converting solar radiation to electricity by way of the Seebeck effect in which charge carrier mobility is generated by an asymmetric thermal differential. The present study builds upon these latest advancements in the state-of-the-art of thermoelectric system management by combining solar evacuated tube technology with commercially available Bismuth Telluride semiconductor modules. The target heat source is solar radiation and the target heat sink is thermal convection into the ambient air relying on wind aided forced convection. These sources of energy are reproduced in a laboratory controlled environment in order to maintain a thermal dipole across a thermoelectric module. The apparatus is then tested in a natural environment. The novelty of the present work lies in a net thermoelectric power gain for ambient environment applications and an experimental validation of theoretical electrical characteristics relative to a varying electrical load. - Highlights: • Solar radiation maintains a thermal tension which drives an electromotive force. • Voltage, current and electric power are reported and discussed. • Theoretical optimal thermoelectric conversion predictions are presented. • Theory is validated with experimentally measured data

  7. Operational Experience from Solar Thermal Energy Projects

    Science.gov (United States)

    Cameron, C. P.

    1984-01-01

    Over the past few years, Sandia National Laboratories were involved in the design, construction, and operation of a number of DOE-sponsored solar thermal energy systems. Among the systems currently in operation are several industrial process heat projects and the Modular Industrial Solar Retrofit qualification test systems, all of which use parabolic troughs, and the Shenandoah Total Energy Project, which uses parabolic dishes. Operational experience has provided insight to both desirable and undesirable features of the designs of these systems. Features of these systems which are also relevant to the design of parabolic concentrator thermal electric systems are discussed. Other design features discussed are system control functions which were found to be especially convenient or effective, such as local concentrator controls, rainwash controls, and system response to changing isolation. Drive systems are also discussed with particular emphasis of the need for reliability and the usefulness of a manual drive capability.

  8. Special conference on thermal energy 'Yugoslavia 1986'

    International Nuclear Information System (INIS)

    This volume contains various papers held at the conference 'Thermoenergetica 1986'. The papers cover subjects ranging from the development of thermal energy in Yugoslavia via fluidized-bed combustion and experience gained with the construction and operation of coal-fuelled plants to the grinding and combustion of coals rich in inerts, pollution problems, fouling and slag formation, service life, stress-induced crack corrosions, and to the planning, construction and operation of nuclear power plants. (HAG)

  9. Fully integrated surface-subsurface flow modelling of groundwater-lake interaction in an esker aquifer: Model verification with stable isotopes and airborne thermal imaging

    Science.gov (United States)

    Ala-aho, Pertti; Rossi, Pekka M.; Isokangas, Elina; Kløve, Bjørn

    2015-03-01

    Water resources management is moving towards integration, where groundwater (GW), surface water (SW) and related aquatic ecosystems are considered one management unit. Because of this paradigm shift, more information and new tools are needed to understand the ecologically relevant fluxes (water, heat, solutes) at the GW-SW interface. This study estimated the magnitude, temporal variability and spatial distribution of water fluxes at the GW-SW interface using a fully integrated hydrological modelling code (HydroGeoSphere). The model domain comprised a hydrologically complex esker aquifer in Northern Finland with interconnected lakes, streams and wetlands. The model was calibrated in steady state for soil hydraulic conductivity and anisotropy and it reproduced the hydraulic head and stream baseflow distribution throughout the aquifer in both transient and steady state modes. In a novel analysis, model outputs were compared with the locations and magnitude of GW discharge to lakes estimated using field techniques. Spatial occurrence of GW-lake interaction was interpreted from airborne thermal infrared imaging. The observed GW inflow locations coincided well with model nodes showing positive exchange flux between surface and subsurface domains. Order of magnitude of simulated GW inflow to lakes showed good agreement with flux values calculated with a stable water isotope technique. Finally, time series of GW inflow, extracted as model output, showed moderate annual variability and demonstrated different interannual inflow changes in seepage and drainage lakes of the aquifer. Overall, this study demonstrated the ability of a fully integrated numerical model to reproduce observed GW-SW exchange processes in a complex unconfined aquifer system. The model-based estimates obtained for GW influx magnitude and spatial distribution, along with information on GW quality can be used to estimate ecologically relevant fluxes in future water resources management.

  10. Analysis of lunar regolith thermal energy storage

    Science.gov (United States)

    Colozza, Anthony J.

    1991-01-01

    The concept of using lunar regolith as a thermal energy storage medium was evaluated. The concept was examined by mathematically modeling the absorption and transfer of heat by the lunar regolith. Regolith thermal and physical properties were established through various sources as functions of temperature. Two cases were considered: a semi-infinite, constant temperature, cylindrical heat source embedded in a continuum of lunar regolith and a spherically shaped molten zone of lunar regolith set with an initial temperature profile. The cylindrical analysis was performed in order to examine the amount of energy which can be stored in the regolith during the day. At night, the cylinder acted as a perfect insulator. This cycling was performed until a steady state situation was reached in the surrounding regolith. It was determined that a cycling steady state occurs after approximately 15 day/night cycles. Results were obtained for cylinders of various diameters. The spherical molten zone analysis was performed to establish the amount of thermal energy, within the regolith, necessary to maintain some molten material throughout a nighttime period. This surrounding temperature profile was modeled after the cycling steady state temperature profile established by the cylindrical analysis. It was determined that a molten sphere diameter of 4.76 m is needed to maintain a core temperature near the low end of the melting temperature range throughout one nighttime period.

  11. Revisit ocean thermal energy conversion system

    International Nuclear Information System (INIS)

    The earth, covered more than 70.8% by the ocean, receives most of its energy from the sun. Solar energy is transmitted through the atmosphere and efficiently collected and stored in the surface layer of the ocean, largely in the tropical zone. Some of the energy is re-emitted to the atmosphere to drive the hydrologic cycle and wind. The wind field returns some of the energy to the ocean in the form of waves and currents. The majority of the absorbed solar energy is stored in vertical thermal gradients near the surface layer of the ocean, most of which is in the tropical region. This thermal energy replenished each day by the sun in the tropical ocean represents a tremendous pollution-free energy resource for human civilization. Ocean Thermal Energy Conversion (OTEC) technology refers to a mechanical system that utilizes the natural temperature gradient that exists in the tropical ocean between the warm surface water and the deep cold water, to generate electricity and produce other economically valuable by-products. The science and engineering behind OTEC have been studied in the US since the mid-seventies, supported early by the U.S. Government and later by State and private industries. There are two general types of OTEC designs: closed-cycle plants utilize the evaporation of a working fluid, such as ammonia or propylene, to drive the turbine-generator, and open-cycle plants use steam from evaporated sea water to run the turbine. Another commonly known design, hybrid plants, is a combination of the two. OTEC requires relatively low operation and maintenance costs and no fossil fuel consumption. OTEC system possesses a formidable potential capacity for renewable energy and offers a significant elimination of greenhouse gases in producing power. In addition to electricity and drinking water, an OTEC system can produce many valuable by-products and side-utilizations, such as: hydrogen, air-conditioning, ice, aquaculture, and agriculture, etc. The potential of these

  12. Aqueous sodium hydroxide seasonal thermal energy storage

    Energy Technology Data Exchange (ETDEWEB)

    Gantenbein, P.; Daguenet-Frick, X.; Frank, E. [Univ. of Applied Sciences Rapperswil (Switzerland). Inst. for Solar Technologies SPF; Weber, R.; Fumey, B. [EMPA Swiss Federal Laboratories for Materials Science and Technology, Duebendorf (Switzerland); Williamson, T. [Kingspan Renewables Ltd, Portadown, Co. Armagh, Northern Ireland (United Kingdom)

    2012-07-01

    Seasonal storage of sensible thermal energy in materials is a challenge in respect to thermal loss corresponding to low volumetric energy density. In a process involving absorption and desorption lower heat losses and higher energy densities can be reached. The working pair sodium hydroxide (NaOH) and water can be employed to this purpose. A possible application of such a system can be a single family passive energy building that requires a maximum power output of approximately 8 kW. The required absorption/desorption zone can be designed as a falling film tube bundle, using either Hu's or Owens' correlations. To meet the required power the tube bundle can be built of 300 mm long tubes with an outer diameter of 12 mm in a configuration of either 3 rows of 18 tubes or 2 rows of 25 tubes. During desorption one row of 18 tubes or 3 rows of 6 tubes are sufficient. In the absorption or discharging process a mass flow of 2 to 4 kg/h of aqueous NaOH with a concentration of 50 wt% NaOH is required. In the reverse process 18 to 30 kg/h of aqueous NaOH at a concentration of 30 wt% are necessary. The mass transport is performed without recirculation, reducing the parasitic power consumption. Initial experiments conducted with a less reactive substitute liquid showed good homogeneous distribution.

  13. Heat-energy storage through semi-opened circulation into low-permeability hard-rock aquifers

    Science.gov (United States)

    Pettenati, Marie; Bour, Olivier; Ausseur, Jean-Yves; de Dreuzy, Jean-Raynald; de la Bernardie, Jérôme; Chatton, Eliot; Lesueur, Hervé; Bethencourt, Lorine; Mougin, Bruno; Aquilina, Luc; Koch, Florian; Dewandel, Benoit; Boisson, Alexandre; Mosser, Jean-François; Pauwels, Hélène

    2016-04-01

    In low-permeability environments, the solutions of heat storage are still limited to the capacities of geothermal borehole heat exchangers. The ANR Stock-en-Socle project explores the possibilities of periodic storage of sensitive heat1 in low-permeability environments that would offer much better performance than that of borehole heat exchangers, especially in terms of unit capacity. This project examines the storage possibilities of using semi-open water circulation in typically a Standing Column Well (SCW), using the strong heterogeneity of hard-rock aquifers in targeting the least favorable areas for water resources. To solve the main scientific issues, which include evaluating the minimum level of permeability required around a well as well as its evolution through time (increase and decrease) due to water-rock interaction processes, the study is based on an experimental program of fieldwork and modelling for studying the thermal, hydraulic and geochemical processes involved. This includes tracer and water-circulation tests by injecting hot water in different wells located in distinct hard-rock settings (i.e. granite and schist) in Brittany, Ploemeur (H+ observatory network) and Naizin. A numerical modelling approach allows studying the effects of permeability structures on the storage and heat-recovery capacities, whereas the modelling of reactive transfers will provide an understanding of how permeability evolves under the influence of dissolution and precipitation. Based on the obtained results, technical solutions will be studied for constructing a well of the SCW type in a low-permeability environment. This work will be completed by a technical and economic feasibility study leading to an investment and operations model. This study aims to describe the suitability of SCW storage for shallow geothermal energy. In order to reach these objectives, Stock-en-Socle is constructed around a public/private partnership between two public research organizations, G

  14. Maximizing Thermal Efficiency and Optimizing Energy Management (Fact Sheet)

    Energy Technology Data Exchange (ETDEWEB)

    2012-03-01

    Researchers at the Thermal Test Facility (TTF) on the campus of the U.S. Department of Energy's National Renewable Energy Laboratory (NREL) in Golden, Colorado, are addressing maximizing thermal efficiency and optimizing energy management through analysis of efficient heating, ventilating, and air conditioning (HVAC) strategies, automated home energy management (AHEM), and energy storage systems.

  15. Nanowires for thermal energy conversion and management

    Science.gov (United States)

    Chen, Renkun

    This dissertation presents the application of nanowires in two aspects of thermal energy conversion and management: (i) silicon (Si) nanowires as efficient and scalable thermoelectric materials due to the reduced thermal conductivity (k), and (ii) Si and copper (Cu) nanowire arrays for enhanced phase change heat transfer including boiling and evaporation and their applications in thermal management of microelectronics. In the first half of the thesis (chapter 2 and 3), we describe thermal and thermoelectric measurements of individual Si nanowires for studying phonon transport properties and their potential application in thermoelectrics. A theoretical model based on coherent phonon scattering was developed to explain the experiemental data, which suggests that phonon-boundary scattering is highly frequency dependent. For low frequency (long wavelength) phonons, the transport is nearly ballistic, whereas high frequency or short wavelength phonons scatter diffusively at nanowire boundary. The competition between the two phonon transmission regimes results in the unusual linear behavior of the thermal conductance of thin VLS Si nanowires at low temperature. Next, the thermal conductivity of EE Si nanowires, which have much rougher surface compared to VLS nanowires, was measured and found to be five-eight times lower than that of VLS counterparts with similar diameters. The substantial reduction in k is presumably due to the higher surface roughness, since both types of nanowires have single crystalline cores. In particular, for ˜ 50 nm EE Si nanowires etched from 0.1 O-cm B-doped p-Si (˜2 x 1017 cm-3 dopant concentration), the k is around 1.6 Wm-1K-1 and the kL is ˜1.2 Wm-1 K-1 at room temperature, approaching that of amorphous Si. The single nanowire measurements show the great promise of using Si nanowire arrays as high-performance, scalable thermoelectric materials. As the second focus of the thesis (chapter 4 and 5), nanowire arrays were used for enhanced phase

  16. Ocean thermal energy conversion: Perspective and status

    Science.gov (United States)

    Thomas, Anthony; Hillis, David L.

    The use of the thermal gradient between the warm surface waters and the deep cold waters of tropical oceans was first proposed by J. A. d'Arsonval in 1881 and tried unsuccessfully by George Claude in 1930. Interest in Ocean Thermal Energy Conversion (OTEC) and other renewable energy sources revived in the 1970s as a result of oil embargoes. At that time, the emphasis was on large floating plants miles from shore producing 250 to 400 MW for maintained grids. When the problems of such plants became better understood and the price of oil reversed its upward trend, the emphasis shifted to smaller (10 MW) shore based plants on tropical islands. Such plants would be especially attractive if they produce fresh water as a by-product. During the past 15 years, major progress has been made in converting OTEC unknowns into knowns. Mini-OTEC proved the closed cycle concept. Cost effective heat exchanger concepts were identified. An effective biofouling control technique was discovered. Aluminum was determined to be promising for OTEC heat exchangers. Heat transfer augmentation techniques were identified, which promised a reduction on heat exchanger size and cost. Fresh water was produced by an OTEC open cycle flash evaporator, using the heat energy in the seawater itself. The current R and D emphasis is on the design and construction of a test facility to demonstrate the technical feasibility of the open cycle process. The 10 MW shore-based, closed cycle plant can be built with today's technology; with the incorporation of a flash evaporator, it will produce fresh water as well as electrical power; both valuable commodities on many tropical islands. The open cycle process has unknowns that require solution before the technical feasibility can be demonstrated. The economic viability of either cycle depends on reducing the capital costs of OTEC plants and on future trends in the costs of conventional energy sources.

  17. Thermal energy recovering device for vitrification product

    International Nuclear Information System (INIS)

    A number of vitrification products in which high level radioactive wastes are vitrified and sealed are contained in a low temperature flon evaporation furnace. A predetermined amount of liquefied flon is contained in the low temperature flon evaporation furnace as a recovering coolant for thermal energy released from the glass vitrification products. The top portion (on the side of a gas layer) and a bottom portion (on the side of a liquid layer) of the low temperature flon evaporation furnace are connected by a cycle line equipped with a turbine electric generator and a condensator in the midway. The liquid flon is gassified by the thermal energy released from the vitrification products, and flon vapors are generated. The flon vapors are introduced to the turbine of a turbo-electric generator by the cycle line to generate electricity. Then, the flon vapors are cooled and condensed by a condensator and returned to the liquid layer of the low temperature flon evaporation furnace. (I.N.)

  18. The thermal solar energy - September 2010

    International Nuclear Information System (INIS)

    The author first notices that the use of solar heat to produce electricity is much lesser known than the production of electricity by photovoltaic effect. He also notices that few efforts have been made in France to develop this technology (thermal solar energy, also called helio-thermodynamics). He evokes the Themis project and also some initiatives in Spain and in California. He recalls some data about solar heat, presents the solar concentration technique which either uses a parabolic configuration (point focus concentration) or a cylindrical and parabolic configuration (line concentration system). He briefly presents the different techniques used to transform solar heat into electricity and to store the electricity. He briefly presents different solutions which have been tested over the past years in France, Germany, Spain, California and Israel (tower and air, gas and Stirling cycle, tower and direct vapour production, cylindrical-parabolic collector). He discusses the effect of intermittency and the French context, and questions and discusses the choice between thermal and photovoltaic solar energy (advantages and drawbacks)

  19. Passive Collecting of Solar Radiation Energy using Transparent Thermal Insulators, Energetic Efficiency of Transparent Thermal Insulators

    OpenAIRE

    Smajo Sulejmanovic; Suad Kunosic; Ema Hankic

    2014-01-01

    This paper explains passive collection of solar radiation energy using transparent thermal insulators. Transparent thermal insulators are transparent for sunlight, at the same time those are very good thermal insulators. Transparent thermal insulators can be placed instead of standard conventional thermal insulators and additionally transparent insulators can capture solar radiation, transform it into heat and save heat just as standard insulators. Using transparent insulators would lead to r...

  20. Potential benefits of thermal energy storage in the proposed Twin Cities district heating-cogeneration system. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Meyer, C.F.

    1979-10-01

    A new, large, cogeneration-district heating system has been proposed for the Twin Cities area, using hot water in a closed-loop system. The proposed system, as described by Studsvik Energiteknik AB of Sweden, does not employ thermal energy storage (TES). Four cases have been developed, describing system configurations which would employ TES, to evaluate the potential benefits of incorporating annual-cycle TES into the Twin Cities system. The potential benefits are found to be substantial, confirming results of earlier, generic studies of aquifer TES. The reference (Studsvik) system employs oil-fired boilers to supplement cogenerated heat, for handling peak loads and providing standby reserve. TES can serve the same function, with net energy savings in spite of heat losses during storage, by making it possible to operate the cogeneration equipment at higher capacity factors. Coal replaces oil as the fuel consumed. Energy savings of the reference system are impressive; energy savings with TES are 2 to 22% better. Capital cost requirements for boilers, cogeneration equipment, and pipelines are reduced by $66 to $258 million. The breakeven capital cost of TES is estimated to range from $43 to $76 per kilowatt peak thermal input to or withdrawal from aquifer TES. A factor in evaluating the breakeven operating cost of TES is the $14 to $31 million per year saving in cost of fuel. Abatement of air pollution and thermal pollution are concomitant benefits.

  1. Quantification of the contribution of the Beauce groundwater aquifer to the discharge of the Loire River using thermal infrared satellite imaging

    Science.gov (United States)

    Lalot, E.; Curie, F.; Wawrzyniak, V.; Baratelli, F.; Schomburgk, S.; Flipo, N.; Piegay, H.; Moatar, F.

    2015-11-01

    Seven Landsat thermal infrared (TIR) images taken over the period 2000-2010 were used to establish longitudinal temperature profiles of the middle Loire River where it flows above the Beauce aquifer. The groundwater discharge along the river course was quantified for each identified groundwater catchment area using a heat budget based on temperature variations of the Loire River estimated from the TIR images. The results showed that 75 % of the temperature differences, between in situ observations and TIR image-based estimations, remained within the ±1 °C interval. The main discharge area of the Beauce aquifer into the Loire River was located between river kilometers 630 and 650, where there was a temperature drop of 1-1.5 °C in the summer and a rise of 0.5 °C in winter. According to the heat budgets, groundwater discharge was higher during the winter period (13.5 m3 s-1) than during the summer period (5.3 m3 s-1). These findings are in line with the results of both a groundwater budget and a process-based distributed hydrogeological model. Groundwater input was also found to be higher during the Loire's flow recession periods.

  2. Heat pipe solar receiver with thermal energy storage

    Science.gov (United States)

    Zimmerman, W. F.

    1981-01-01

    An HPSR Stirling engine generator system featuring latent heat thermal energy storge, excellent thermal stability and self regulating, effective thermal transport at low system delta T is described. The system was supported by component technology testing of heat pipes and of thermal storage and energy transport models which define the expected performance of the system. Preliminary and detailed design efforts were completed and manufacturing of HPSR components has begun.

  3. Proceedings of the 27th intersociety energy conversion engineering conference

    International Nuclear Information System (INIS)

    This book contains proceedings of the 27th Intersociety Energy Conversion Engineering Conference. Topics covered include: Aquifer Thermal Storage; Energy Storage Technology and Magnetic Bearing Applications; New Technologies for Energy Utilization: Superconductivity; Thermal Storage; Nuclear Fission and Fusion Power; Thermal Management of Energy Systems; Marine Energy; new Technologies for Energy Utilization: Advanced and Innovative Concepts; and Alternative Fuels

  4. Development of MEMS based pyroelectric thermal energy harvesters

    Science.gov (United States)

    Hunter, Scott R.; Lavrik, Nickolay V.; Bannuru, Thirumalesh; Mostafa, Salwa; Rajic, Slo; Datskos, Panos G.

    2011-06-01

    The efficient conversion of waste thermal energy into electrical energy is of considerable interest due to the huge sources of low-grade thermal energy available in technologically advanced societies. Our group at the Oak Ridge National Laboratory (ORNL) is developing a new type of high efficiency thermal waste heat energy converter that can be used to actively cool electronic devices, concentrated photovoltaic solar cells, computers and large waste heat producing systems, while generating electricity that can be used to power remote monitoring sensor systems, or recycled to provide electrical power. The energy harvester is a temperature cycled pyroelectric thermal-to-electrical energy harvester that can be used to generate electrical energy from thermal waste streams with temperature gradients of only a few degrees. The approach uses a resonantly driven pyroelectric capacitive bimorph cantilever structure that potentially has energy conversion efficiencies several times those of any previously demonstrated pyroelectric or thermoelectric thermal energy harvesters. The goals of this effort are to demonstrate the feasibility of fabricating high conversion efficiency MEMS based pyroelectric energy converters that can be fabricated into scalable arrays using well known microscale fabrication techniques and materials. These fabrication efforts are supported by detailed modeling studies of the pyroelectric energy converter structures to demonstrate the energy conversion efficiencies and electrical energy generation capabilities of these energy converters. This paper reports on the modeling, fabrication and testing of test structures and single element devices that demonstrate the potential of this technology for the development of high efficiency thermal-to-electrical energy harvesters.

  5. MEMS based pyroelectric thermal energy harvester

    Science.gov (United States)

    Hunter, Scott R; Datskos, Panagiotis G

    2013-08-27

    A pyroelectric thermal energy harvesting apparatus for generating an electric current includes a cantilevered layered pyroelectric capacitor extending between a first surface and a second surface, where the first surface includes a temperature difference from the second surface. The layered pyroelectric capacitor includes a conductive, bimetal top electrode layer, an intermediate pyroelectric dielectric layer and a conductive bottom electrode layer. In addition, a pair of proof masses is affixed at a distal end of the layered pyroelectric capacitor to face the first surface and the second surface, wherein the proof masses oscillate between the first surface and the second surface such that a pyroelectric current is generated in the pyroelectric capacitor due to temperature cycling when the proof masses alternately contact the first surface and the second surface.

  6. Low temperature thermal energy storage: a state-of-the-art survey

    Energy Technology Data Exchange (ETDEWEB)

    Baylin, F.

    1979-07-01

    The preliminary version of an analysis of activities in research, development, and demonstration of low temperature thermal energy storage (TES) technologies having applications in renewable energy systems is presented. Three major categories of thermal storage devices are considered: sensible heat; phase change materials (PCM); and reversible thermochemical reactions. Both short-term and annual thermal energy storage technologies based on prinicples of sensible heat are discussed. Storage media considered are water, earth, and rocks. Annual storage technologies include solar ponds, aquifers, and large tanks or beds of water, earth, or rocks. PCM storage devices considered employ salt hydrates and organic compounds. The sole application of reversible chemical reactions outlined is for the chemical heat pump. All program processes from basic research through commercialization efforts are investigated. Nongovernment-funded industrial programs and foreign efforts are outlined as well. Data describing low temperature TES activities are presented also as project descriptions. Projects for all these programs are grouped into seven categories: short-term sensible heat storage; annual sensible heat storage; PCM storage; heat transfer and exchange; industrial waste heat recovery and storage; reversible chemical reaction storage; and models, economic analyses, and support studies. Summary information about yearly funding and brief descriptions of project goals and accomplishments are included.

  7. Solar Thermal energy strategic road-map

    International Nuclear Information System (INIS)

    The French Environment and Energy Management Agency (ADEME) manages a fund dedicated to new energy technologies. Since 2008 this fund has funded 'research demonstrators' to implement testing of technologies that are in an experimental stage, between research and industrial deployment. ADEME coordinates a group of experts who are charged with drawing up a strategic road-map prior to each Call for Expressions of Interest. The aims of the solar thermal road-map are: - to highlight the industrial, technological, environmental and societal issues at stake; - to elaborate coherent, consistent and shared visions of the technologies and/or socio-technical systems outlined in the road-map; - to underscore the technological, organisational and socioeconomic barriers and bottlenecks to be overcome in order to achieve these visions; - to link priority research topics to a timetable of goals for technology availability and deployment that is consistent with the stated objectives; - to give priority to research needs and research demonstrators that will serve as the basis for: 1 - calls for expression of interest issued by the Research Demonstrators Fund, 2 - the research programming process at ADEME and more broadly at the Agence nationale de la recherche (ANR) and the Comite strategique national sur la recherche sur l'energie. Research priorities and needs for demonstrators are determined by the intersection of visions and bottlenecks. They also take into account industrial and research capacity in France. The road-maps may also refer to exemplary research demonstrators abroad that are in the forefront of technological progress, and make recommendations regarding industrial policy. These road-maps are the result of collective work by a group of experts appointed by the Steering Committee (Comite de pilotage, COPIL) of the Research Demonstrators Fund for new energy technologies. The members of this group are actors in research, drawn from industry, research bodies and research

  8. Solar-thermal conversion and thermal energy storage of graphene foam-based composites

    Science.gov (United States)

    Zhang, Lianbin; Li, Renyuan; Tang, Bo; Wang, Peng

    2016-07-01

    Among various utilizations of solar energy, solar-thermal conversion has recently gained renewed research interest due to its extremely high energy efficiency. However, one limiting factor common to all solar-based energy conversion technologies is the intermittent nature of solar irradiation, which makes them unable to stand-alone to satisfy the continuous energy need. Herein, we report a three-dimensional (3D) graphene foam and phase change material (PCM) composite for the seamlessly combined solar-thermal conversion and thermal storage for sustained energy release. The composite is obtained by infiltrating the 3D graphene foam with a commonly used PCM, paraffin wax. The high macroporosity and low density of the graphene foam allow for high weight fraction of the PCM to be incorporated, which enhances the heat storage capacity of the composite. The interconnected graphene sheets in the composite provide (1) the solar-thermal conversion capability, (2) high thermal conductivity and (3) form stability of the composite. Under light irradiation, the composite effectively collects and converts the light energy into thermal energy, and the converted thermal energy is stored in the PCM and released in an elongated period of time for sustained utilization. This study provides a promising route for sustainable utilization of solar energy.Among various utilizations of solar energy, solar-thermal conversion has recently gained renewed research interest due to its extremely high energy efficiency. However, one limiting factor common to all solar-based energy conversion technologies is the intermittent nature of solar irradiation, which makes them unable to stand-alone to satisfy the continuous energy need. Herein, we report a three-dimensional (3D) graphene foam and phase change material (PCM) composite for the seamlessly combined solar-thermal conversion and thermal storage for sustained energy release. The composite is obtained by infiltrating the 3D graphene foam with a

  9. District Energy Corporation SW 40th Street Thermal Energy Plant

    Energy Technology Data Exchange (ETDEWEB)

    Davlin, Thomas [District Energy Corporation, Lincoln, NE (United States)

    2014-06-06

    The overall deliverable from the project is the design, construction and commissioning of a detention facility heating and cooling system that minimizes ownership costs and maximizes efficiency (and therefore minimizes environmental impact). The primary deliverables were the proof of concept for the application of geothermal systems for an institutional facility and the ongoing, quarterly system operating data downloads to the Department of Energy . The primary advantage of geothermal based heat pump systems is the higher efficiency of the system compared to a conventional chiller, boiler, cooling tower based system. The higher efficiency results in a smaller environmental foot print and lower energy costs for the detention facility owner, Lancaster County. The higher efficiency for building cooling is primarily due to a more constant compressor condensing temperature with the geothermal well field acting as a thermal “sink” (in place of the conventional system’s cooling tower). In the heating mode, Ground Couple Heat Pump (GCHP) systems benefits from the advantage of a heat pump Coefficient of Performance (COP) of approximately 3.6, significantly better than a conventional gas boiler. The geothermal well field acting as a thermal “source” allows the heat pumps to operate efficiently in the heating mode regardless of ambient temperatures. The well field is partially located in a wetland with a high water table so, over time, the project will be able to identify the thermal loading characteristics of a well field located in a high water table location. The project demonstrated how a large geothermal well field can be installed in a wetland area in an economical and environmentally sound manner. Finally, the SW 40th Street Thermal Energy Plant project demonstrates the benefits of providing domestic hot water energy, as well as space heating, to help balance well filed thermal loading in a cooling dominated application. During the period of August 2012 thru

  10. Ozark Aquifer

    Data.gov (United States)

    Kansas Data Access and Support Center — These digital maps contain information on the altitude of the base and top, the extent, and the potentiometric surface of the Ozark aquifer in Kansas. The Ozark...

  11. Mathematical modeling of moving boundary problems in thermal energy storage

    Science.gov (United States)

    Solomon, A. D.

    1980-01-01

    The capability for predicting the performance of thermal energy storage (RES) subsystems and components using PCM's based on mathematical and physical models is developed. Mathematical models of the dynamic thermal behavior of (TES) subsystems using PCM's based on solutions of the moving boundary thermal conduction problem and on heat and mass transfer engineering correlations are also discussed.

  12. Composite materials for thermal energy storage: enhancing performance through microstructures.

    Science.gov (United States)

    Ge, Zhiwei; Ye, Feng; Ding, Yulong

    2014-05-01

    Chemical incompatibility and low thermal conductivity issues of molten-salt-based thermal energy storage materials can be addressed by using microstructured composites. Using a eutectic mixture of lithium and sodium carbonates as molten salt, magnesium oxide as supporting material, and graphite as thermal conductivity enhancer, the microstructural development, chemical compatibility, thermal stability, thermal conductivity, and thermal energy storage performance of composite materials are investigated. The ceramic supporting material is essential for preventing salt leakage and hence provides a solution to the chemical incompatibility issue. The use of graphite gives a significant enhancement on the thermal conductivity of the composite. Analyses suggest that the experimentally observed microstructural development of the composite is associated with the wettability of the salt on the ceramic substrate and that on the thermal conduction enhancer. PMID:24591286

  13. Energy Partitions and Evolution in a Purely Thermal Solar Flare

    CERN Document Server

    Fleishman, Gregory D; Gary, Dale E

    2015-01-01

    This paper presents a solely thermal flare, which we detected in the microwave range from the thermal gyro- and free-free emission it produced. An advantage of analyzing thermal gyro emission is its unique ability to precisely yield the magnetic field in the radiating volume. When combined with observationally-deduced plasma density and temperature, these magnetic field measurements offer a straightforward way of tracking evolution of the magnetic and thermal energies in the flare. For the event described here, the magnetic energy density in the radio-emitting volume declines over the flare rise phase, then stays roughly constant during the extended peak phase, but recovers to the original level over the decay phase. At the stage where the magnetic energy density decreases, the thermal energy density increases; however, this increase is insufficient, by roughly an order of magnitude, to compensate for the magnetic energy decrease. When the magnetic energy release is over, the source parameters come back to ne...

  14. Chemically and Thermally Stable High Energy Density Silicone Composites Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Thermal energy storage systems with 300 ? 1000 kJ/kg energy density through either phase changes or chemical heat absorption are sought by NASA. This proposed...

  15. REVIEW ON PHASE CHANGE MATERIALAS THERMAL ENERGY STORAGE

    OpenAIRE

    Bharti H. Verma; S V PRAYAGI; J. A. Gotmare

    2014-01-01

    Energy demands in the commercial, industrial, and utility sectors vary on daily, weekly, and seasonal bases. These demands can be matched with the help of thermal energy storage (TES) systems. This paper presentsTES using phase change material (PCMs) and their application. The use of latent heat storage system using phase change material (PCM) is an effective way of storing thermal energy and has advantages of high energy storage density and isothermal nature of the storage pro...

  16. Complex water management in modern agriculture: Trends in the water-energy-food nexus over the High Plains Aquifer.

    Science.gov (United States)

    Smidt, Samuel J; Haacker, Erin M K; Kendall, Anthony D; Deines, Jillian M; Pei, Lisi; Cotterman, Kayla A; Li, Haoyang; Liu, Xiao; Basso, Bruno; Hyndman, David W

    2016-10-01

    In modern agriculture, the interplay between complex physical, agricultural, and socioeconomic water use drivers must be fully understood to successfully manage water supplies on extended timescales. This is particularly evident across large portions of the High Plains Aquifer where groundwater levels have declined at unsustainable rates despite improvements in both the efficiency of water use and water productivity in agricultural practices. Improved technology and land use practices have not mitigated groundwater level declines, thus water management strategies must adapt accordingly or risk further resource loss. In this study, we analyze the water-energy-food nexus over the High Plains Aquifer as a framework to isolate the major drivers that have shaped the history, and will direct the future, of water use in modern agriculture. Based on this analysis, we conclude that future water management strategies can benefit from: (1) prioritizing farmer profit to encourage decision-making that aligns with strategic objectives, (2) management of water as both an input into the water-energy-food nexus and a key incentive for farmers, (3) adaptive frameworks that allow for short-term objectives within long-term goals, (4) innovative strategies that fit within restrictive political frameworks, (5) reduced production risks to aid farmer decision-making, and (6) increasing the political desire to conserve valuable water resources. This research sets the foundation to address water management as a function of complex decision-making trends linked to the water-energy-food nexus. Water management strategy recommendations are made based on the objective of balancing farmer profit and conserving water resources to ensure future agricultural production. PMID:27344509

  17. Investigation of Solar and Solar-Gas Thermal Energy Sources

    Directory of Open Access Journals (Sweden)

    Jan Zupa

    2003-01-01

    Full Text Available The article deals with the investigation of solar thermal sources of electrical and heat energy as well as the investigation of hybrid solar-gas thermal sources of electrical and heat energy (so called photothermal sources. Photothermal sources presented here utilize computer-controlled injection of the conversion fluid into special capillary porous substance that is adjusted to direct temperature treatment by the concentrated thermal radiation absorption.

  18. Investigation of Solar and Solar-Gas Thermal Energy Sources

    OpenAIRE

    Jan Zupa; Ivan Herec

    2003-01-01

    The article deals with the investigation of solar thermal sources of electrical and heat energy as well as the investigation of hybrid solar-gas thermal sources of electrical and heat energy (so called photothermal sources). Photothermal sources presented here utilize computer-controlled injection of the conversion fluid into special capillary porous substance that is adjusted to direct temperature treatment by the concentrated thermal radiation absorption.

  19. Solar-thermal conversion and thermal energy storage of graphene foam-based composite

    KAUST Repository

    Zhang, Lianbin

    2016-07-11

    Among various utilizations of solar energy, solar-thermal conversion has recently gained renewed research interest due to its extremely high energy efficiency. However, one limiting factor common to all solar-based energy conversion technologies is the intermittent nature of solar irradiation, which makes them unable to stand-alone to satisfy continuous energy need. Herein, we report a three-dimensional (3D) graphene foam and phase change material (PCM) composite for the seamlessly combined solar-thermal conversion and thermal storage for sustained energy release. The composite is obtained by infiltrating the 3D graphene foam with a commonly used PCM, paraffin wax. The high macroporosity and low density of the graphene foam allow for high weight fraction of the PCM to be incorporated, which enhances heat storage capacity of the composite. The interconnected graphene sheets in the composite provide (1) the solar-thermal conversion capability, (2) high thermal conductivity and (3) form stability of the composite. Under light irradiation, the composite effectively collects and converts the light energy into thermal energy, and the converted thermal energy is stored in the PCM and released in an elongated period of time for sustained utilization. This study provides a promising route for sustainable utilization of solar energy.

  20. Solar-thermal conversion and thermal energy storage of graphene foam-based composites.

    Science.gov (United States)

    Zhang, Lianbin; Li, Renyuan; Tang, Bo; Wang, Peng

    2016-08-14

    Among various utilizations of solar energy, solar-thermal conversion has recently gained renewed research interest due to its extremely high energy efficiency. However, one limiting factor common to all solar-based energy conversion technologies is the intermittent nature of solar irradiation, which makes them unable to stand-alone to satisfy the continuous energy need. Herein, we report a three-dimensional (3D) graphene foam and phase change material (PCM) composite for the seamlessly combined solar-thermal conversion and thermal storage for sustained energy release. The composite is obtained by infiltrating the 3D graphene foam with a commonly used PCM, paraffin wax. The high macroporosity and low density of the graphene foam allow for high weight fraction of the PCM to be incorporated, which enhances the heat storage capacity of the composite. The interconnected graphene sheets in the composite provide (1) the solar-thermal conversion capability, (2) high thermal conductivity and (3) form stability of the composite. Under light irradiation, the composite effectively collects and converts the light energy into thermal energy, and the converted thermal energy is stored in the PCM and released in an elongated period of time for sustained utilization. This study provides a promising route for sustainable utilization of solar energy. PMID:27430282

  1. Economic feasibility of thermal energy storage systems

    Energy Technology Data Exchange (ETDEWEB)

    Habeebullah, B.A. [Faculty of Engineering, King Abdulaziz University, Jeddah (Saudi Arabia)

    2007-07-01

    This paper investigates the economic feasibility of both building an ice thermal storage and structure a time of rate tariff for the unique air conditioning (A/C) plant of the Grand Holy Mosque of Makkah, Saudi Arabia. The features of the building are unique where the air-conditioned 39,300 m{sup 2} zone is open to the atmosphere and the worshippers fully occupy the building five times a day, in addition hundreds of thousands of worshippers attend the blessed weekend's prayer at noontime, which escalates the peak electricity load. For economic analysis, the objective function is the daily electricity bill that includes the operation cost and the capital investment of the ice storage system. The operation cost is function of the energy imported for operating the plant in which the tariff structure, number of operating hours and the ambient temperature are parameters. The capital recovery factor is calculated for 10% interest rate and payback period of 10 years. Full and partial load storage scenarios are considered. The results showed that with the current fixed electricity rate (0.07 $/kWh), there is no gain in introducing ice storage systems for both storage schemes. Combining energy storage and an incentive time structured rate showed reasonable daily bill savings. For base tariff of 0.07 $/kWh during daytime operation and 0.016 $/kWh for off-peak period, savings were achieved for full load storage scenario. Different tariff structure is discussed and the break-even nighttime rate was determined (varies between 0.008 and 0.03 $/kWh). Partial load storage scenario showed to be unattractive where the savings for the base structured tariff was insignificant. (author)

  2. Flight experiment of thermal energy storage

    Science.gov (United States)

    Namkoong, David

    1989-01-01

    Thermal energy storage (TES) enables a solar dynamic system to deliver constant electric power through periods of sun and shade. Brayton and Stirling power systems under current considerations for missions in the near future require working fluid temperatures in the 1100 to 1300+ K range. TES materials that meet these requirements fall into the fluoride family of salts. These salts store energy as a heat of fusion, thereby transferring heat to the fluid at constant temperature during shade. The principal feature of fluorides that must be taken into account is the change in volume that occurs with melting and freezing. Salts shrink as they solidify, a change reaching 30 percent for some salts. The location of voids that form as result of the shrinkage is critical when the solar dynamic system reemerges into the sun. Hot spots can develop in the TES container or the container can become distorted if the melting salt cannot expand elsewhere. Analysis of the transient, two-phase phenomenon is being incorporated into a three-dimensional computer code. The code is capable of analysis under microgravity as well as 1 g. The objective of the flight program is to verify the predictions of the code, particularly of the void location and its effect on containment temperature. The four experimental packages comprising the program will be the first tests of melting and freezing conducted under microgravity. Each test package will be installed in a Getaway Special container to be carried by the shuttle. The package will be self-contained and independent of shuttle operations other than the initial opening of the container lid and the final closing of the lid. Upon the return of the test package from flight, the TES container will be radiographed and finally partitioned to examine the exact location and shape of the void. Visual inspection of the void and the temperature data during flight will constitute the bases for code verification.

  3. Process and device for thermal energy production

    International Nuclear Information System (INIS)

    The main aim of the invention is to create a heating cycle arrangement, for the energy production facilities as from liquid metal cooled nuclear reactors, that will stand up to the temperature changes of the heated steam at least as from the high pressure turbine. This arrangement includes a first system in which flows a liquid metal coolant between a heat source, a steam generator and a utilisation system on which flows a vaporisable fluid from this generator, passing through a first turbine, a heater, at least a second turbine and a condenser. The steam heated in the heater is heated by the liquid metal coolant. A preheater is located in the heated steam system upstream of the heater. This preheater is connected so as to heat the steam to a preset, practically constant value, before this steam to be heated enters the heater heated by the liquid metal. This arrangement reduces the thermal transitions in the superheater and the heater during load changes. In a preferential design mode, the steam from the steam generator is sent to a moisture extraction drum and the heater is exposed to the steam in this drum

  4. Compressed-Air Energy Storage: Preliminary design and site development program in an aquifer. Volume 7: Environmental, safety, and licensing considerations

    Science.gov (United States)

    1981-07-01

    The behavior and suitability of aquifers as compressed-air energy storage (CAFS) sites was studied. The probability, severity, and recommended control measures for the environmental and safety impacts that could result from the construction and operation of a CAES facility are described. The permits and approvals that would be required and the time estimated for their acquisition are also described.

  5. Passive Collecting of Solar Radiation Energy using Transparent Thermal Insulators, Energetic Efficiency of Transparent Thermal Insulators

    Directory of Open Access Journals (Sweden)

    Smajo Sulejmanovic

    2014-11-01

    Full Text Available This paper explains passive collection of solar radiation energy using transparent thermal insulators. Transparent thermal insulators are transparent for sunlight, at the same time those are very good thermal insulators. Transparent thermal insulators can be placed instead of standard conventional thermal insulators and additionally transparent insulators can capture solar radiation, transform it into heat and save heat just as standard insulators. Using transparent insulators would lead to reduce in usage of fossil fuels and would help protection of an environment and reduce effects of global warming, etc.

  6. Low-Temperature Thermal Energy Storage Program. Annual progress report, October 1977--September 1978

    Energy Technology Data Exchange (ETDEWEB)

    Brunton, G.D.; Eissenberg, D.M.; Kedl, R.J.

    1979-05-01

    The Low-Temperature Thermal Energy Storage (LTTES) Program is part of a national effort to develop means for reducing United States dependence on oil and natural gas as primary energy sources. To this end, LTTES addresses the development of advanced sensible and latent heat storage technologies that permit substitution by solar or off-peak electrical energies or permit conservation by recovery and reuse of waste heat. Emphasis is on applying these technologies to heating and cooling of buildings. As the LTTES program continued to mature, a number of technologies were identified for development emphasis, including (1) seasonal storage of hot and cold water from waste or natural sources in aquifers, (2) short-term or daily storage of heat or coolness from solar or off-peak electrical sources in phase-change materials, and (3) recovery and reuse of rejected industrial heat through thermal storage. These areas have been further divided into three major and four minor activities; significant accomplishments are reported for each.

  7. Thermal energy and charge currents in multi-terminal nanorings

    Science.gov (United States)

    Kramer, Tobias; Kreisbeck, Christoph; Riha, Christian; Chiatti, Olivio; Buchholz, Sven S.; Wieck, Andreas D.; Reuter, Dirk; Fischer, Saskia F.

    2016-06-01

    We study in experiment and theory thermal energy and charge transfer close to the quantum limit in a ballistic nanodevice, consisting of multiply connected one-dimensional electron waveguides. The fabricated device is based on an AlGaAs/GaAs heterostructure and is covered by a global top-gate to steer the thermal energy and charge transfer in the presence of a temperature gradient, which is established by a heating current. The estimate of the heat transfer by means of thermal noise measurements shows the device acting as a switch for charge and thermal energy transfer. The wave-packet simulations are based on the multi-terminal Landauer-Büttiker approach and confirm the experimental finding of a mode-dependent redistribution of the thermal energy current, if a scatterer breaks the device symmetry.

  8. Fluctuation and thermal energy balance for drift-wave turbulence

    International Nuclear Information System (INIS)

    Energy conservation for the drift-wave system is shown to be separated into the wave-energy power balance equation and an ambient thermal-energy transport equation containing the anomalous transport fluxes produced by the fluctuations. The wave energy equation relates the wave energy density and wave energy flux to the anomalous transport flux and the dissipation of the fluctuations. The thermal balance equation determines the evolution of the temperature profiles from the divergence of the anomalous heat flux, the collisional heating and cooling mechanisms and the toroidal pumping effect. 16 refs., 1 tab

  9. Rapid Charging of Thermal Energy Storage Materials through Plasmonic Heating

    OpenAIRE

    Zhongyong Wang; Peng Tao; Yang Liu; Hao Xu; Qinxian Ye; Hang Hu; Chengyi Song; Zhaoping Chen; Wen Shang; Tao Deng

    2014-01-01

    Direct collection, conversion and storage of solar radiation as thermal energy are crucial to the efficient utilization of renewable solar energy and the reduction of global carbon footprint. This work reports a facile approach for rapid and efficient charging of thermal energy storage materials by the instant and intense photothermal effect of uniformly distributed plasmonic nanoparticles. Upon illumination with both green laser light and sunlight, the prepared plasmonic nanocomposites with ...

  10. Guarani aquifer

    International Nuclear Information System (INIS)

    The environmental protection and sustain ability develop project of Guarani Aquifer System is a join work from Argentina, Brazil, Paraguay and Uruguay with a purpose to increase the knowledge resource and propose technical legal and organizational framework for sustainable management between countries.The Universities funds were created as regional universities support in promotion, training and academic research activities related to environmental al social aspects of the Guarani Aquifer System.The aim of the project is the management and protection of the underground waters resources taking advantage and assesment for nowadays and future generations

  11. Alternative biomass sources for thermal energy generation

    Science.gov (United States)

    Steensen, Torge; Müller, Sönke; Dresen, Boris; Büscher, Olaf

    2015-04-01

    of Bottrop-Kirchhellen in the state of North Rhine-Westphalia. This region consists of nature reserves, forests, farmland and a few villages. To present a qualitative comparison between simulated and true biomass volume, we conducted field work by mapping the spatial extent of the desired biomass occurrences in the area. First results indicate a qualitative match of about 75%. Our research highlights the small-scale biomass features that have not been incorporated in previous biomass estimates. With the regular trimming and the accompanied raw material that becomes available, a new sector of thermal energy generation can be outlined. An automated quantification using satellite and GIS data will allow a regular monitoring of the vegetation growth and an assessment of the transport routes and costs as well as the location of the prospective power plants. In the endeavour of creating a sustainable energy supply, these biomass units should not be neglected, especially since the usage of the traditional units is limited due to competing interests in food production and nature conservation.

  12. Heat storage in the Hettangian aquifer in Berlin - results from a column experiment

    Science.gov (United States)

    Milkus, Chri(Sch)augott

    2015-04-01

    Aquifer Thermal Energy Storage (ATES) is a sustainable alternative for storage and seasonal availability of thermal energy. However, its impact on the subsurface flow regime is not well known. In Berlin (Germany), the Jurassic (Hettangian) sandstone aquifer with highly mineralized groundwater (TDS 27 g/L) is currently used for heat storage. The aim of this study was to examine the hydrogeochemical changes that are caused by the induced temperature shift and its effects on the hydraulic permeability of the aquifer. Column experiments were conducted, in which stainless steel columns were filled with sediment from the aquifer and flushed with native groundwater for several weeks. The initial temperature of the experiment was 20°C, comparable to the in-situ conditions within the aquifer. After reaching equilibrium between sediment and water, the temperature was increased to simulate heating of the aquifer. During the experiment, physical and chemical parameters (pH, ORP, dissolved oxygen and dissolved carbon dioxide) were measured at the outflow of the column and the effluent water was sampled. Using a Scanning Electron Microscope, the deposition of precipitated minerals and biofilm on sediment grains was analyzed. Changes in hydraulic properties of the sediment were studied by the use of tracer tests with Uranin.

  13. Guide to Setting Thermal Comfort Criteria and Minimizing Energy Use in Delivering Thermal Comfort

    Energy Technology Data Exchange (ETDEWEB)

    Regnier, Cindy

    2012-08-31

    Historically thermal comfort in buildings has been controlled by simple dry bulb temperature settings. As we move into more sophisticated low energy building systems that make use of alternate systems such as natural ventilation, mixed mode system and radiant thermal conditioning strategies, a more complete understanding of human comfort is needed for both design and control. This guide will support building designers, owners, operators and other stakeholders in defining quantifiable thermal comfort parameters?these can be used to support design, energy analysis and the evaluation of the thermal comfort benefits of design strategies. This guide also contains information that building owners and operators will find helpful for understanding the core concepts of thermal comfort. Whether for one building, or for a portfolio of buildings, this guide will also assist owners and designers in how to identify the mechanisms of thermal comfort and space conditioning strategies most important for their building and climate, and provide guidance towards low energy design options and operations that can successfully address thermal comfort. An example of low energy design options for thermal comfort is presented in some detail for cooling, while the fundamentals to follow a similar approach for heating are presented.

  14. Residential building thermal performance energy efficiency in Yangtze River basin

    Institute of Scientific and Technical Information of China (English)

    王厚华; 庄燕燕; 吴伟伟

    2009-01-01

    Using energy consumption software VisualDOE4.0,simulation was carried out on the energy consumption of a typical residential building in Yangtze River basin,with a focus on thermal performance of envelope each component and application of total heating recovery equipment. The effects of thermal performance of building envelope each component on energy efficiency ratio were analyzed. Comprehensive measures schemes of energy saving were designed by the orthogonal experiment. The energy efficiency ratios of different envelopes combination schemes were gained. Finally,the optimize combination scheme was confirmed. With the measurement dates,the correctness of the simulation dates was completely verified.

  15. Geological factors affecting the chemical characteristics of the thermal waters of the carbonate karstified aquifers of Northern Vietnam

    OpenAIRE

    Drogue, C.; Cat, N. N.; Dazy, J.

    2000-01-01

    In northern Vietnam, exposed carbonate rock formations cover an area of more than 50,000 km2 .Their accumulated thickness from the Cambrian to the Triassic is in some places as much as 3000 m. Numerous thermal waters (springs and wells) occur in these strongly karstified carbonate massifs. This is the result of significant ancient and present orogenic activity, as the region demonstrates by its strong seismic activity. These karstic formations are water-bearing and strongly recharge...

  16. Geological factors affecting the chemical characteristics of the thermal waters of the carbonate karstified aquifers of Northern Vietnam

    OpenAIRE

    Drogue, C.; Cat, N. N.; Dazy, J.

    2002-01-01

    In northern Vietnam, exposed carbonate rock formations cover an area of more than 50,000 km2 .Their accumulated thickness from the Cambrian to the Triassic is in some places as much as 3000 m. Numerous thermal waters (springs and wells) occur in these strongly karstified carbonate massifs. This is the result of significant ancient and present orogenic activity, as the region demonstrates by its strong seismic activity. These karstic ...

  17. Solar photovoltaic/thermal (hybrid) energy project

    Science.gov (United States)

    Sheldon, D. B.

    1981-09-01

    Development of photovoltaic/thermal (PV/T) collectors and residential heat pump systems is reported. Candidate collector and residential heat pump systems were evaluated using the TRNSYS computer program. It is found that combined heat pump and PV array is a promising method for achieving economical solar cooling. Where the cooling load is dominant, exclusively PV collectors rather than PV/T collectors are preferred. Where the heating load is dominant, the thermal component of PV/T collectors makes a significant contribution to heating a residence. PV/T collectors were developed whose combined efficiency approaches the efficiency of a double glazed, exclusively thermal collector. The design and operational problems of air source heat pumps are reviewed. Possible effects of compressor startup transients on PV power system operation are discussed.

  18. Metal hydrides based high energy density thermal battery

    International Nuclear Information System (INIS)

    Highlights: • The principle of the thermal battery using advanced metal hydrides was demonstrated. • The thermal battery used MgH2 and TiMnV as a working pair. • High energy density can be achieved by the use of MgH2 to store thermal energy. - Abstract: A concept of thermal battery based on advanced metal hydrides was studied for heating and cooling of cabins in electric vehicles. The system utilized a pair of thermodynamically matched metal hydrides as energy storage media. The pair of hydrides that was identified and developed was: (1) catalyzed MgH2 as the high temperature hydride material, due to its high energy density and enhanced kinetics; and (2) TiV0.62Mn1.5 alloy as the matching low temperature hydride. Further, a proof-of-concept prototype was built and tested, demonstrating the potential of the system as HVAC for transportation vehicles

  19. Energy consumption in buildings and female thermal demand

    Science.gov (United States)

    Kingma, Boris; van Marken Lichtenbelt, Wouter

    2015-12-01

    Energy consumption of residential buildings and offices adds up to about 30% of total carbon dioxide emissions; and occupant behaviour contributes to 80% of the variation in energy consumption. Indoor climate regulations are based on an empirical thermal comfort model that was developed in the 1960s (ref. ). Standard values for one of its primary variables--metabolic rate--are based on an average male, and may overestimate female metabolic rate by up to 35% (ref. ). This may cause buildings to be intrinsically non-energy-efficient in providing comfort to females. Therefore, we make a case to use actual metabolic rates. Moreover, with a biophysical analysis we illustrate the effect of miscalculating metabolic rate on female thermal demand. The approach is fundamentally different from current empirical thermal comfort models and builds up predictions from the physical and physiological constraints, rather than statistical association to thermal comfort. It provides a substantiation of the thermal comfort standard on the population level and adds flexibility to predict thermal demand of subpopulations and individuals. Ultimately, an accurate representation of thermal demand of all occupants leads to actual energy consumption predictions and real energy savings of buildings that are designed and operated by the buildings services community.

  20. Quantum Energy Teleportation between Spin Particles in Thermal Equilibrium

    CERN Document Server

    Frey, Michael

    2013-01-01

    Quantum energy teleportation is the transfer of energy between two physically separated, but quantum correlated, sites, accomplished without an external energy carrier, using a three-step LOCC (local operations and classical communication) protocol. We apply this LOCC teleportation protocol to a Heisenberg spin particle pair initially in a quantum thermal state, making temperature an explicit parameter. The thermal states of the spin pair are quantum correlated (entangled or otherwise) at all temperatures. We find that energy teleportation is possible at any temperature, even at temperatures above the threshold where the particles' entanglement vanishes. This shows for thermal spin states that entanglement is not fundamentally necessary for energy teleportation; quantum correlation other than entanglement can suffice. This is a new instance in which quantum dissonance (quantum correlation without entanglement) is seen to act as a quantum resource. We compare energy teleportation to particle B with direct loca...

  1. Applications of thermal energy storage in the cement industry

    Science.gov (United States)

    Jaeger, F. A.; Beshore, D. G.; Miller, F. M.; Gartner, E. M.

    1978-01-01

    In the manufacture of cement, literally trillions of Btu's are rejected to the environment each year. The purpose of this feasibility study program was to determine whether thermal energy storage could be used to conserve or allow alternative uses of this rejected energy. This study identifies and quantifies the sources of rejected energy in the cement manufacturing process, established use of this energy, investigates various storage system concepts, and selects energy conservation systems for further study. Thermal performance and economic analyses are performed on candidate storage systems for four typical cement plants representing various methods of manufacturing cement. Through the use of thermal energy storage in conjunction with waste heat electric power generation units, an estimated 2.4 x 10 to the 13th power Btu/year, or an equivalent on investment of the proposed systems are an incentive for further development.

  2. Analyzing Control Challenges for Thermal Energy Storage in Foodstuffs

    DEFF Research Database (Denmark)

    Hovgaard, Tobias Gybel; Larsen, Lars F. S.; Skovrup, Morten Juel;

    2012-01-01

    We consider two important challenges that arise when thermal energy is to be stored in foodstuffs. We have previously introduced economic optimizing MPC schemes that both reduce operating costs and offer flexible power consumption in a future Smart Grid. The goal is to utilize the thermal capacit...... different timescales and for estimating maximum energy storage time. The results are shown for a large range of parameters, and with specific calculations for selected foodstuff items....

  3. Equilibrium geochemical modeling of a seasonal thermal energy storage aquifer field test

    Science.gov (United States)

    Stottlemyre, J. S.

    1980-01-01

    A geochemical mathematical modeling study designed to investigate the well plugging problems encountered at the Auburn University experimental field tests is summarized. The results, primarily of qualitative interest, include: (1) loss of injectivity was probably due to a combination of native particulate plugging and clay swelling and dispersion; (2) fluid-fluid incompatibilities, hydrothermal reactions, and oxidation reactions were of insignificant magnitude or too slow to have contributed markedly to the plugging; and (3) the potential for and contributions from temperature-induced dissolved gas solubility reductions, capillary boundary layer viscosity increases, and microstructural deformation cannot be deconvolved from the available data.

  4. Laser-assisted manufacturing of thermal energy devices

    Science.gov (United States)

    Zhang, Tao; Tewolde, Mahder; Kim, Ki-Hoon; Seo, Dong-Min; Longtin, Jon P.; Hwang, David J.

    2016-03-01

    In this study, we will present recent progress in the laser-assisted manufacturing of thermal energy devices that require suppressed thermal transport characteristics yet maintaining other functionalities such as electronic transport or mechanical strength. Examples of such devices to be demonstrated include thermoelectric generator or insulating materials. To this end, it will be shown that an additive manufacturing approaches can be facilitated and improved by unique processing capabilities of lasers in composite level. In order to tailor thermal characteristics in thermal devices, we will mainly investigate the potential of laser heating, curing, selective removal and sintering processes of material systems in the composite level.

  5. Smart Building: Decision Making Architecture for Thermal Energy Management.

    Science.gov (United States)

    Uribe, Oscar Hernández; Martin, Juan Pablo San; Garcia-Alegre, María C; Santos, Matilde; Guinea, Domingo

    2015-01-01

    Smart applications of the Internet of Things are improving the performance of buildings, reducing energy demand. Local and smart networks, soft computing methodologies, machine intelligence algorithms and pervasive sensors are some of the basics of energy optimization strategies developed for the benefit of environmental sustainability and user comfort. This work presents a distributed sensor-processor-communication decision-making architecture to improve the acquisition, storage and transfer of thermal energy in buildings. The developed system is implemented in a near Zero-Energy Building (nZEB) prototype equipped with a built-in thermal solar collector, where optical properties are analysed; a low enthalpy geothermal accumulation system, segmented in different temperature zones; and an envelope that includes a dynamic thermal barrier. An intelligent control of this dynamic thermal barrier is applied to reduce the thermal energy demand (heating and cooling) caused by daily and seasonal weather variations. Simulations and experimental results are presented to highlight the nZEB thermal energy reduction. PMID:26528978

  6. Smart Building: Decision Making Architecture for Thermal Energy Management

    Directory of Open Access Journals (Sweden)

    Oscar Hernández Uribe

    2015-10-01

    Full Text Available Smart applications of the Internet of Things are improving the performance of buildings, reducing energy demand. Local and smart networks, soft computing methodologies, machine intelligence algorithms and pervasive sensors are some of the basics of energy optimization strategies developed for the benefit of environmental sustainability and user comfort. This work presents a distributed sensor-processor-communication decision-making architecture to improve the acquisition, storage and transfer of thermal energy in buildings. The developed system is implemented in a near Zero-Energy Building (nZEB prototype equipped with a built-in thermal solar collector, where optical properties are analysed; a low enthalpy geothermal accumulation system, segmented in different temperature zones; and an envelope that includes a dynamic thermal barrier. An intelligent control of this dynamic thermal barrier is applied to reduce the thermal energy demand (heating and cooling caused by daily and seasonal weather variations. Simulations and experimental results are presented to highlight the nZEB thermal energy reduction.

  7. Potential energy savings and thermal comfort

    DEFF Research Database (Denmark)

    Jensen, Karsten Ingerslev; Rudbeck, Claus Christian; Schultz, Jørgen Munthe

    1996-01-01

    Results of simulations carried out on four different buildings with common windows, commercial low-energy windows and xerogel windows are presented. The results are the annual energy consumption for space heating and the indoor air temperature level....

  8. Thermally driven electrokinetic energy conversion with liquid water microjets

    Science.gov (United States)

    Lam, Royce K.; Gamlieli, Zach; Harris, Stephen J.; Saykally, Richard J.

    2015-11-01

    A goal of current energy research is to design systems and devices that can efficiently exploit waste heat and utilize solar or geothermal heat energy for electrical power generation. We demonstrate a novel technique exploiting water's large coefficient of thermal expansion, wherein modest thermal gradients produce the requisite high pressure for driving fast-flowing liquid water microjets, which can effect the direct conversion of the kinetic energy into electricity and gaseous hydrogen. Waste heat in thermoelectric generating plants and combustion engines, as well as solar and geothermal energy could be used to drive these systems.

  9. High Density Thermal Energy Storage with Supercritical Fluids

    Science.gov (United States)

    Ganapathi, Gani B.; Wirz, Richard

    2012-01-01

    A novel approach to storing thermal energy with supercritical fluids is being investigated, which if successful, promises to transform the way thermal energy is captured and utilized. The use of supercritical fluids allows cost-affordable high-density storage with a combination of latent heat and sensible heat in the two-phase as well as the supercritical state. This technology will enhance penetration of several thermal power generation applications and high temperature water for commercial use if the overall cost of the technology can be demonstrated to be lower than the current state-of-the-art molten salt using sodium nitrate and potassium nitrate eutectic mixtures.

  10. estec2007 - 3rd European solar thermal energy conference. Proceedings

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2007-12-14

    The sessions of the 'estec2007 - 3{sup rd} European Solar Thermal Energy Conference held in Freiburg, Germany have the following titles: The solar thermal sector at a turning point; Cooling and Process Heat, Country reports Europe; Standards and Certification; Country reports outside Europe; Awareness raising and marketing; Domestic hot water and space heating; Domestic hot water and space heating; Quality Assurance and Solar Thermal Energy Service Companies; Collectors and other key technical issues; Policy - Financial incentives; Country Reports; Marketing and Awareness Raising; Quality Assurance Measures/Monistoring; Standards and Certification; Collectors; Domestic Hot Water and Space Heating; Industrial Process Heat; Storage; Solar Cooling. (AKF)

  11. Thermal Energy Storage in Building Integrated Thermal Systems: A Review. Part 2. Integration as Passive System

    OpenAIRE

    Niall, Dervilla; McCormack, Sarah; Griffiths, Philip; Cabeza, Luisa; Navarro, Lidia; Castell, Albert; de Grazia, Alvaro; Brown, Maria

    2015-01-01

    Energy consumption trends in residential and commercial buildings show a significant increase in recent decades. One of the key points for reducing energy consumption in buildings is to decrease the energy demand. Buildings envelopes are not just a structure they also provide protection from outdoor weather conditions always taking into account the local climate. Thermal energy storage has been used and applied to the building structure by taking advantage of sensible heat storage of material...

  12. Thermal energy transport in a surface phonon-polariton crystal

    Science.gov (United States)

    Ordonez-Miranda, Jose; Tranchant, Laurent; Joulain, Karl; Ezzahri, Younes; Drevillon, Jérémie; Volz, Sebastian

    2016-01-01

    We demonstrate that the energy transport of surface phonon polaritons can efficiently be observed in a crystal made up of a three-dimensional assembly of spheroidal nanoparticles of silicon carbide. The ultralow phonon thermal conductivity of this nanostructure, along with its high surface area-to-volume ratio, allows the predominance of the polariton energy over that generated by phonons. The polariton dispersion relation, propagation length, and thermal conductance are numerically determined as functions of the size, shape, and temperature of the nanoparticles. It is shown that the thermal conductance of a crystal with prolate nanoparticles at 500 K and a minor (major) axis of 50 nm (5 μ m ) is 0.5 nW K-1 , which is comparable to the quantum of thermal conductance of polar nanowires. We also show that a nanoparticle size dispersion of up to 200 nm does not change significantly the polariton energy, which supports the technological feasibility of the proposed crystal.

  13. Global Energetics of Solar Flares: III. Non thermal Energies

    CERN Document Server

    Aschwanden, Markus J; O'Flannagain, Aidan; Campi, Amir; McTiernan, James M; Konter, Eduard

    2016-01-01

    This study entails the third part of a global flare energetics project, in which RHESSI data of 193 M and X-class flare events from the first 3.5 yrs of the SDO) mission are analyzed. We fit a thermal and a nonthermal component to RHESSI spectra, yielding the temperature of the differential emission measure (DEM) tail, the nonthermal power law slope and flux, and the thermal/nonthermal cross-over energy. From these parameters we calculate the total non thermal energy in electrons with two different methods: (i) using the observed cross-over energy as low-energy cutoff, and (ii) using the low-energy cutoff predicted by the warm thick-target bremsstrahlung model of Kontar et al. We find commensurable ranges of the low-energy or 21+/-6 keV for the cross-over method, and 18+/-6 keV for the warm-target model. Comparing with the statistics of magnetically dissipated energies and thermal energies in the two previous studies, we find the following mean (logarithmic) energy ratios: E_nt=0.07 E_mag, and E_th=0.74 E_Na,...

  14. Compressed-air energy-storage preliminary design and site-development program in an aquifer. Volume 7: Environmental, safety and licensing considerations

    Science.gov (United States)

    1982-12-01

    The suitability of aquifers as compressed air energy storage (CAES) sites was examined. The methodology and results of the study are described. The probability, severity, and recommended control measures for the environmental and safety impacts that could result from the construction and operation of a CAES facility are outlined. The permits and approvals that would be required and the time estimated for their acquisition are also described.

  15. Magneto-Thermo-Triboelectric Generator (MTTG) for thermal energy harvesting

    Science.gov (United States)

    Jang, Kwang Yeop; Lee, James; Lee, Dong-Gun

    2016-04-01

    We present a novel thermal energy harvesting system using triboelectric effect. Recently, there has been intensive research efforts on energy harvesting using triboelectric effect, which can produce surprising amount of electric power (when compared to piezoelectric materials) by rubbing or touching (i.e, electric charge by contact and separation) two different materials together. Numerous studies have shown the possibility as an attractive alternative with good transparency, flexibility and low cost abilities for its use in wearable device and smart phone applications markets. However, its application has been limited to only vibration source, which can produce sustained oscillation with maintaining contact and separation states repeatedly for triboelectric effect. Thus, there has been no attempt toward thermal energy source. The proposed approach can convert thermal energy into electricity by pairing triboelectric effect and active ferromagnetic materials The objective of the research is to develop a new manufacturing process of design, fabrication, and testing of a Magneto-Thermo-Triboelectric Generator (MTTG). The results obtained from the approach show that MTTG devices have a feasible power energy conversion capability from thermal energy sources. The tunable design of the device is such that it has efficient thermal capture over a wide range of operation temperature in waste heat.

  16. SURVEY OF EPA FACILITIES FOR SOLAR THERMAL ENERGY APPLICATIONS

    Science.gov (United States)

    A study was done to assess the feasibility of applying solar thermal energy systems to EPA facilities. A survey was conducted to determine those EPA facilities where solar energy could best be used. These systems were optimized for each specific application and the system/facilit...

  17. Mapping Thermal Energy Resource Potentials from Wastewater Treatment Plants

    OpenAIRE

    Georg Neugebauer; Florian Kretschmer; René Kollmann; Michael Narodoslawsky; Thomas Ertl; Gernot Stoeglehner

    2015-01-01

    Wastewater heat recovery via heat exchangers and heat pumps constitutes an environmentally friendly, approved and economically competitive, but often underestimated technology. By introducing the spatial dimension in feasibility studies, the results of calculations change considerably. This paper presents a methodology to estimate thermal energy resource potentials of wastewater treatment plants taking spatial contexts into account. In close proximity to settlement areas, wastewater energy ca...

  18. Simulation of thermocline thermal energy storage system using C

    Directory of Open Access Journals (Sweden)

    Meseret Tesfay

    2013-06-01

    Full Text Available Solar thermal power generation is a modern technology, which has already shown feasible results in the production of electricity. Thermal energy storage (TES is a crucial element in solar energy applications, which includes the increase of building thermal capacity, solar water heating systems for domestic use, and Concentrated Solar Thermal power plants for electricity generation. Economic, efficient and reliable thermal energy storage systems are a key need of solar thermal power plants, in order to smooth out the insolation changes during intermittent cloudy weather condition or during night period, to allow the operation. To address this goal, based on the parabolic trough power plants, sensible heat storage system with operation temperature between 300°C – 390°C can be used. The goal of this research is to design TES which can produce 1MWe. In this work simulation is performed to analyze the Liquid medium STES using C. In this case different liquid medium TESs is investigated and out of all mixed-media single-tank thermocline TES is selected and designed based on the Schumann equation. In particular, this equation is numerically solved, in order to determine energy storage, at different locations and time inside the storage tank. Finally, due to their feasibility, low cost of manufacturing and maintenance are designed and sized to the minimum possible volume.

  19. Thermal power in the Swedish energy supply

    International Nuclear Information System (INIS)

    A survey is presented of the part played by thermal power plants including nuclear plants in the Swedish electric power supply system. The Swedish and Norwegian situations are compared. The background for the present structure is outlined and the optimisation of electricity production is briefly discussed. The Nordic grid is presented and the strategy and charges discussed. The prognosis for the development in Sweden is presented with a brief discussion of the influence of industrial development. Finally the responsibility of the politicians for the continued development is discussed. (JIW)

  20. Modeling Thermal and Environmental Effects of Prototype Scale Ocean Thermal Energy Conversion

    Science.gov (United States)

    Hamrick, J. M.

    2010-12-01

    Ocean thermal energy conversion (OTEC) utilizes the temperature difference between the mix lay and deep water electricity generation. The small temperature difference compared to other thermal-electric generation devises, typically between 20 and 25 C, requires the substantial volumetric flows on the order of hundreds of cubic meters per second to generate net energy and recover capital investments. This presentation described the use of a high resolution three-dimensional EFDC model with an embedded jet-plume model to simulate the thermal and environmental impacts of a number of prototype OTEC configurations on the southwest coast of Oahu, Hawaii. The EFDC model is one-way nested into a larger scale ROMS model to allow for realistic incorporation of region processes including external and internal tides and sub-tidal circulation. Impacts on local thermal structure and the potential for nutrient enrichment of the mixed layer are addressed with model and presented.

  1. Energy flow and thermal comfort in buildings

    DEFF Research Database (Denmark)

    Le Dreau, Jerome

    insulated buildings (R > 5 m2.K/W). In case of single-storey building with a low level of insulation, the effectiveness of radiant terminals is lower due to the larger back losses, and an air-based terminal might be more energy-efficient than a radiant terminal (in terms of delivered energy). Regarding...... based on both radiation and convection. Radiant terminals have the advantage of making use of low grade sources (i.e. low temperature heating and high temperature cooling), thus decreasing the primary energy consumption of buildings. But there is a lack of knowledge on the heat transfer from the...... beam. The higher the air change rate and the warmer the outdoor air, the larger the savings achieved with a radiant cooling terminals. Therefore radiant terminals have a large potential of energy savings for buildings with high ventilation rates (e.g. shop, train station, industrial storage). Among...

  2. Micro rectennas: Brownian ratchets for thermal-energy harvesting

    International Nuclear Information System (INIS)

    We experimentally demonstrated the operation of a rectenna for harvesting thermal (blackbody) radiation and converting it into dc electric power. The device integrates an ultrafast rectifier, the self-switching nanodiode, with a wideband log-periodic spiral microantenna. The radiation from the thermal source drives the rectenna out of thermal equilibrium, permitting the rectification of the excess thermal fluctuations from the antenna. The power conversion efficiency increases with the source temperatures up to 0.02% at 973 K. The low efficiency is attributed mainly to the impedance mismatch between antenna and rectifier, and partially to the large field of view of the antenna. Our device not only opens a potential solution for harvesting thermal energy but also provides a platform for experimenting with Brownian ratchets

  3. Micro rectennas: Brownian ratchets for thermal-energy harvesting

    Energy Technology Data Exchange (ETDEWEB)

    Pan, Y.; Powell, C. V.; Balocco, C., E-mail: claudio.balocco@durham.ac.uk [School of Engineering and Computing Sciences, Durham University, Durham DH1 3LE (United Kingdom); Song, A. M. [School of Electrical and Electronic Engineering, University of Manchester, Manchester M13 9PL (United Kingdom)

    2014-12-22

    We experimentally demonstrated the operation of a rectenna for harvesting thermal (blackbody) radiation and converting it into dc electric power. The device integrates an ultrafast rectifier, the self-switching nanodiode, with a wideband log-periodic spiral microantenna. The radiation from the thermal source drives the rectenna out of thermal equilibrium, permitting the rectification of the excess thermal fluctuations from the antenna. The power conversion efficiency increases with the source temperatures up to 0.02% at 973 K. The low efficiency is attributed mainly to the impedance mismatch between antenna and rectifier, and partially to the large field of view of the antenna. Our device not only opens a potential solution for harvesting thermal energy but also provides a platform for experimenting with Brownian ratchets.

  4. Metal hydrides for concentrating solar thermal power energy storage

    Science.gov (United States)

    Sheppard, D. A.; Paskevicius, M.; Humphries, T. D.; Felderhoff, M.; Capurso, G.; Bellosta von Colbe, J.; Dornheim, M.; Klassen, T.; Ward, P. A.; Teprovich, J. A.; Corgnale, C.; Zidan, R.; Grant, D. M.; Buckley, C. E.

    2016-04-01

    The development of alternative methods for thermal energy storage is important for improving the efficiency and decreasing the cost of concentrating solar thermal power. We focus on the underlying technology that allows metal hydrides to function as thermal energy storage (TES) systems and highlight the current state-of-the-art materials that can operate at temperatures as low as room temperature and as high as 1100 °C. The potential of metal hydrides for thermal storage is explored, while current knowledge gaps about hydride properties, such as hydride thermodynamics, intrinsic kinetics and cyclic stability, are identified. The engineering challenges associated with utilising metal hydrides for high-temperature TES are also addressed.

  5. Conversion of broadband to narrowband thermal emission through energy recycling

    Science.gov (United States)

    de Zoysa, Menaka; Asano, Takashi; Mochizuki, Keita; Oskooi, Ardavan; Inoue, Takuya; Noda, Susumu

    2012-08-01

    Converting from a broadband to a narrowband thermal emission spectrum with minimal loss of energy is important in the creation of efficient environmental sensors and biosensors as well as thermo-photovoltaic power generation systems. Here, we demonstrate such thermal emission control by manipulating photonic modes with photonic crystals as well as material absorption with quantum-well intersubband transitions. We show that the emission peak intensity for our device can be more than four times greater than that of a blackbody sample under the same input power and thermal management conditions due to an increase in the temperature compared to the blackbody reference, and the emission bandwidth and angular spread are narrowed by a factor of 30 and 8, respectively. These results indicate that the energy saved by thermal emission control can be recycled and concentrated to enhance the narrow peak emission intensity.

  6. Study of thermal energy storage using fluidized bed heat exchangers

    Science.gov (United States)

    Weast, T. E.; Shannon, L. J.; Ananth, K. P.

    1980-01-01

    The technical and economic feasibility of fluid bed heat exchangers (FBHX) for thermal energy storage (TES) in waste heat recovery applications is assessed by analysis of two selected conceptual systems, the rotary cement kiln and the electric arc furnace. It is shown that the inclusion of TES in the energy recovery system requires that the difference in off-peak and on-peak energy rates be large enough so that the value of the recovered energy exceeds the value of the stored energy by a wide enough margin to offset parasitic power and thermal losses. Escalation of on-peak energy rates due to fuel shortages could make the FBHX/TES applications economically attractive in the future.

  7. THERMAL COMFORT ZONES FORSTEADY-STATE ENERGY BALANCE MODEL

    OpenAIRE

    KAYNAKLI, Ömer; Ümit ÜNVER; Muhsin KILIÇ; Recep YAMANKARADENİZ

    2003-01-01

    In this study, the various thermal comfort parameters including temperature, relative humidity, air velocity, metabolic activity and clothing resistance and their effect to each other are examined. The heat transfer equations given for steady state energy balance between body and environment and the empirical equations which give thermal comfort and physiological control mechanisms of body are used. According to the ASHRAE Standard 55-1992, an environment can be assumed comfortable while Pred...

  8. Local Thermal Equilibrium States and Quantum Energy Inequalities

    OpenAIRE

    Schlemmer, Jan; Verch, Rainer

    2008-01-01

    In this paper we investigate the energy distribution of states of a linear scalar quantum field with arbitrary curvature coupling on a curved spacetime which fulfill some local thermality condition. We find that this condition implies a quantum energy inequality for these states, where the (lower) energy bounds depend only on the local temperature distribution and are local and covariant (the dependence of the bounds other than on temperature is on parameters defining the quantum field model,...

  9. Mathematical Optimization Applied to Thermal and Electrical Energy Systems

    OpenAIRE

    Bordin, Chiara

    2015-01-01

    This Thesis aims at building and discussing mathematical models applications focused on Energy problems, both on the thermal and electrical side. The objective is to show how mathematical programming techniques developed within Operational Research can give useful answers in the Energy Sector, how they can provide tools to support decision making processes of Companies operating in the Energy production and distribution and how they can be successfully used to make simulations and sensiti...

  10. Renewable Energy Essentials: Concentrating Solar Thermal Power

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2009-07-01

    Concentrated solar thermal power (CSP) is a re-emerging market. The Luz Company built 354 MWe of commercial plants in California, still in operations today, during 1984-1991. Activity re-started with the construction of an 11-MW plant in Spain, and a 64-MW plant in Nevada, by 2006. There are currently hundreds of MW under construction, and thousands of MW under development worldwide. Spain and the United States together represent 90% of the market. Algeria, Egypt and Morocco are building integrated solar combined cycle plants, while Australia, China, India, Iran, Israel, Italy, Jordan, Mexico, South Africa and the United Arab Emirates are finalising or considering projects. While trough technology remains the dominant technology, several important innovations took place over 2007-2009: the first commercial solar towers, the first commercial plants with multi-hour capacities, the first Linear Fresnel Reflector plants went into line.

  11. Environmental aspect of energy-thermal project

    International Nuclear Information System (INIS)

    Coal based thermal power plants creates several pollutants in the process of generating electricity. The burning of coal releases carbon dioxide , carbon monoxide, oxides of sulphur, oxides of nitrogen, suspended particulate matters and a huge amount of ashes. These pollutants are causing air, water and noise pollution and global warming as well. The flue gases are harmful to living beings and also affecting flora and fauna. Furthermore, the ash produced is degrading the soil, water and atmosphere. Though the pollution is controlled by installing pollution control equipment up to a great extent, it can further be reduced by plantation of various pollution resistant/tolerant plants and trees, directly by leaves, bark and twigs and indirectly by metabolism. In this paper, the effective use of plants and trees to reduce pollution is discussed. Describing the utilization of fly ash in various ways, the authors inscribe on the path of progress that it exists within a healthy environment. 2 figs

  12. Energy conservation in dissipative processes: Teacher expectations and strategies associated with imperceptible thermal energy

    CERN Document Server

    Daane, Abigail R; Vokos, Stamatis; Scherr, Rachel E

    2014-01-01

    Research has demonstrated that many students and some teachers do not consistently apply the conservation of energy principle when analyzing mechanical scenarios. In observing elementary and secondary teachers engaged in learning activities that require tracking and conserving energy, we find that challenges to energy conservation often arise in dissipative scenarios in which kinetic energy transforms into thermal energy (e.g., a ball rolls to a stop). We find that teachers expect that when they can see the motion associated with kinetic energy, they should be able to perceive the warmth associated with thermal energy. Their expectations are violated when the warmth produced is imperceptible. In these cases, teachers reject the idea that the kinetic energy transforms to thermal energy. Our observations suggest that apparent difficulties with energy conservation may have their roots in a strong and productive association between forms of energy and their perceptible indicators. We see teachers resolve these ch...

  13. Thermal energy storage using phase change materials fundamentals and applications

    CERN Document Server

    Fleischer, Amy S

    2015-01-01

    This book presents a comprehensive introduction to the use of solid‐liquid phase change materials to store significant amounts of energy in the latent heat of fusion. The proper selection of materials for different applications is covered in detail, as is the use of high conductivity additives to enhance thermal diffusivity. Dr. Fleischer explores how applications of PCMS have expanded over the past 10 years to include the development of high efficiency building materials to reduce heating and cooling needs, smart material design for clothing, portable electronic systems thermal management, solar thermal power plant design and many others. Additional future research directions and challenges are also discussed.

  14. Thermal energy harvesting for application at MEMS scale

    CERN Document Server

    Percy, Steven; McGarry, Scott; Post, Alex; Moore, Tim; Cavanagh, Kate

    2014-01-01

    This book discusses the history of thermal heat generators and focuses on the potential for these processes using micro-electrical mechanical systems (MEMS) technology for this application. The main focus is on the capture of waste thermal energy for example from industrial processes, transport systems or the human body to generate useable electrical power.  A wide range of technologies is discussed, including external combustion heat cycles at MEMS ( Brayton, Stirling and Rankine), Thermoacoustic, Shape Memory Alloys (SMAs), Multiferroics, Thermionics, Pyroelectric, Seebeck, Alkali Metal Thermal, Hydride Heat Engine, Johnson Thermo Electrochemical Converters, and the Johnson Electric Heat Pipe.

  15. Global Energetics of Solar Flares: II. Thermal Energies

    CERN Document Server

    Aschwanden, M J; Ryan, D; Caspi, A; McTiernan, J M; Warren, H P

    2015-01-01

    We present the second part of a project on the global energetics of solar flares and CMEs that includes about 400 M- and X-class flares observed with AIA/SDO during the first 3.5 years of its mission. In this Paper II we compute the differential emission measure (DEM) distribution functions and associated multi-thermal energies, using a spatially-synthesized Gaussian DEM forward-fitting method. The multi-thermal DEM function yields a significantly higher (by an average factor of $\\approx 14$), but more comprehensive (multi-)thermal energy than an isothermal energy estimate from the same AIA data. We find a statistical energy ratio of $E_{th}/E_{diss} \\approx 2\\%-40\\%$ between the multi-thermal energy $E_{th}$ and the magnetically dissipated energy $E_{diss}$, which is an order of magnitude higher than the estimates of Emslie et al.~2012. For the analyzed set of M and X-class flares we find the following physical parameter ranges: $L=10^{8.2}-10^{9.7}$ cm for the length scale of the flare areas, $T_p=10^{5.7}-...

  16. Pyroelectric energy harvesting using liquid-based switchable thermal interfaces

    Energy Technology Data Exchange (ETDEWEB)

    Cha, G; Ju, YS

    2013-01-15

    The pyroelectric effect offers an intriguing solid-state approach for harvesting ambient thermal energy to power distributed networks of sensors and actuators that are remotely located or otherwise difficult to access. There have been, however, few device-level demonstrations due to challenges in converting spatial temperature gradients into temporal temperature oscillations necessary for pyroelectric energy harvesting. We demonstrate the feasibility of a device concept that uses liquid-based thermal interfaces for rapid switching of the thermal conductance between a pyroelectric material and a heat source/sink and can thereby deliver high output power density. Using a thin film of a pyroelectric co-polymer together with a macroscale mechanical actuator, we operate pyroelectric thermal energy harvesting cycles at frequencies close to 1 Hz. Film-level power densities as high as 110 mW/cm(3) were achieved, limited by slow heat diffusion across a glass substrate. When combined with a laterally interdigitated electrode array and a MEMS actuator, the present design offers an attractive option for compact high-power density thermal energy harvesters. (C) 2012 Elsevier B.V. All rights reserved.

  17. Phase-change thermal energy storage: Final subcontract report

    Energy Technology Data Exchange (ETDEWEB)

    1989-11-01

    The research and development described in this document was conducted within the US Department of Energy's Solar Thermal Technology Program. The goal of this program is to advance the engineering and scientific understanding of solar thermal technology and to establish the technology base from which private industry can develop solar thermal power production options for introduction into the competitive energy market. Solar thermal technology concentrates the solar flux using tracking mirrors or lenses onto a receiver where the solar energy is absorbed as heat and converted into electricity or incorporated into products as process heat. The two primary solar thermal technologies, central receivers and distributed receivers, employ various point and line-focus optics to concentrate sunlight. Current central receiver systems use fields of heliostats (two-axes tracking mirrors) to focus the sun's radiant energy onto a single, tower-mounted receiver. Point focus concentrators up to 17 meters in diameter track the sun in two axes and use parabolic dish mirrors or Fresnel lenses to focus radiant energy onto a receiver. Troughs and bowls are line-focus tracking reflectors that concentrate sunlight onto receiver tubes along their focal lines. Concentrating collector modules can be used alone or in a multimodule system. The concentrated radiant energy absorbed by the solar thermal receiver is transported to the conversion process by a circulating working fluid. Receiver temperatures range from 100{degree}C in low-temperature troughs to over 1500{degree}C in dish and central receiver systems. 12 refs., 119 figs., 4 tabs.

  18. A 3 dimensional model of the potential impacts on an aquifer of two energy storage systems

    International Nuclear Information System (INIS)

    The USGS (United States Geological Survey) SUTRA 3D flow and heat transport code has been used to model the potential for and the impacts of two ground energy storage systems sited in a geology typical of that beneath London. One system is a deep borehole closed system, the other an open injection system. The modelling results show that the impact of the closed system on the environment is small but that energy inputs or outputs must be well balanced if excessive heating or cooling of the ground is to be avoided. The open system can inject heat more efficiently but can cause a larger environmental impact depending on the nature of the site's geology. Further work needs to be undertaken to better understand the magnitude of the heat fluxes in fractured porous media. (authors)

  19. New thermal energies in France. Solar, biomass, geothermal and aero-thermal: which perspectives by 2015?

    International Nuclear Information System (INIS)

    Whereas thermal renewable energies are to become inescapable, and notably 'green heat' which is acclaimed by real estate professionals as well as by industries, their market is foreseen to grow at a rate of 6 per cent a year until 2015. This high rate is notably due to the soaring price of conventional energies like electricity, gas or oil fuel, but also to environmental constraints related to the reduction of greenhouse gas emissions. A first part proposes an overview of the French market of new sources of thermal renewable energies for a domestic use in 2011, and discusses perspectives by 2015. A detailed analysis of the three main technologies (heat pumps, thermal solar devices, wood fuelled domestic heating devices) is proposed and challenges faced by involved enterprises and possible answers provided by professionals are also detailed. A second part gathers and comments data related to thermal energy production for industrial and collective use (in collective housing and office building): energy production level, legal and regulatory framework, evolution of demand, predictions for the different energy sources (wood energy, geothermal, waste energetic valorisation). It also proposes an analysis of stakes related to these applications. The third part proposes an assessment of the size of the different sectors by presenting key economic figures (turnover, staff, etc.). While the fourth part proposes an overview of leaders for each sector (thermal solar, biomass, and heat pump) and a more detailed presentation of 14 important actors, the fifth and last part proposes a large set of financial and economic indicators of 200 involved operators

  20. Thermal Energy Generation in the Earth

    CERN Document Server

    Mayer, Frederick J

    2014-01-01

    We show that a recently introduced class of electromagnetic composite particles can explain some discrepancies in observations involving heat and helium released from the earth. Energy release during the formation of the composites and subsequent nuclear reactions involving the composites are described that can quantitatively account for the discrepancies and are expected to have implications in other areas of geophysics, for example, a new picture of heat production and volcanism in the earth is presented.

  1. Renewable energy balancing with thermal grid support

    OpenAIRE

    Zwaenepoel, Brecht; Vansteenbrugge, Joke; Vandoorn, Tine; VAN EETVELDE, Greet; Vandevelde, Lieven

    2013-01-01

    Waste heat valorisation in process industry is a common strategy today. The residual heat is converted to electricity by using steam turbines or organic Rankine cycles. As this energy conversion is likely constructed as an integral cooling capacity for the primary process, loss of electricity production will result in reduced process cooling and hence production capacity loss. This restriction prevents these generators to deliver supporting services to the electrical grid. In this paper, it i...

  2. Enhancing Low-Grade Thermal Energy Recovery in a Thermally Regenerative Ammonia Battery Using Elevated Temperatures

    KAUST Repository

    Zhang, Fang

    2015-02-13

    © 2015 WILEY-VCH Verlag GmbH & Co. KGaA. A thermally regenerative ammonia battery (TRAB) is a new approach for converting low-grade thermal energy into electricity by using an ammonia electrolyte and copper electrodes. TRAB operation at 72°C produced a power density of 236±8 Wm-2, with a linear decrease in power to 95±5 Wm-2 at 23°C. The improved power at higher temperatures was due to reduced electrode overpotentials and more favorable thermodynamics for the anode reaction (copper oxidation). The energy density varied with temperature and discharge rates, with a maximum of 650 Whm-3 at a discharge energy efficiency of 54% and a temperature of 37°C. The energy efficiency calculated with chemical process simulation software indicated a Carnot-based efficiency of up to 13% and an overall thermal energy recovery of 0.5%. It should be possible to substantially improve these energy recoveries through optimization of electrolyte concentrations and by using improved ion-selective membranes and energy recovery systems such as heat exchangers.

  3. Thermalization in high energy nuclear collisions

    International Nuclear Information System (INIS)

    Complete events of the symmetric collisions Ca+Ca at E/A=400 MeV and 1050 MeV and Nb+Nb at E/A=400 MeV and 650 MeV have been measured with the Plastic Ball/Wall 4 π spectrometer. The degree of isotropy expressed by the ratio of the mean transverse to the mean longitudinal momentum in each event is determined as a function of the charged particle multiplicity. Also discussed are proton energy distributions at thetasub(cm)=900 and their multiplicity dependences. (orig.)

  4. Advanced concepts in ground thermal energy storage systems

    Science.gov (United States)

    Woods, Kevin David

    In recent years, ground thermal energy storage has become a topic of interest in the energy community for solar thermal energy storage systems, ground sourced heat pump systems, and data center thermal management systems due to an increase in the energy efficiency of such systems utilizing the ground as a thermal reservoir. The most common method for transferring thermal energy to the ground formation is the geothermal borehole. This dissertation presents the state of the art in geothermal borehole modeling and derives novel analytical functions to model advanced concepts concerning their operation. The novel solutions derived allow a geothermal borehole designer to better understand and design ground energy storage systems. The state of the art in geothermal borehole modeling is the stationary line source solution which is limited to boreholes operating without groundwater flow. Novel solutions for modeling a geothermal borehole with groundwater advection are presented through derivation of a transient moving line source solution as well as a transient moving cylindrical surface source solution. These solutions are applied to model a specific type of open loop geothermal borehole called a standing column well with groundwater advection and are compared to empirical and numerical data for validation. The dissertation then moves into derivation of a property determination method for geothermal boreholes with groundwater advection. The traditional property determination method used to obtain ground formation properties is based on the stationary transient line source method and fails in the presence of groundwater flow. The proposed novel property determination method calculates the thermal conductivity, thermal diffusivity, and superficial flow velocity of groundwater within a ground formation. These methods and solutions are novel tools allowing for geothermal borehole designers to grasp a better understanding of the systems they are designing as well as open other

  5. Thermal comfort and building energy consumption implications – A review

    International Nuclear Information System (INIS)

    Highlights: • We review studies of thermal comfort and discuss building energy use implications. • Adaptive comfort models tend to have a wider comfort temperature range. • Higher indoor temperatures would lead to fewer cooling systems and less energy use. • Socio-economic study and post-occupancy evaluation of built environment is desirable. • Important to consider future climate scenarios in heating, cooling and power schemes. - Abstract: Buildings account for about 40% of the global energy consumption and contribute over 30% of the CO2 emissions. A large proportion of this energy is used for thermal comfort in buildings. This paper reviews thermal comfort research work and discusses the implications for building energy efficiency. Predicted mean vote works well in air-conditioned spaces but not naturally ventilated buildings, whereas adaptive models tend to have a broader comfort temperature ranges. Higher indoor temperatures in summertime conditions would lead to less prevalence of cooling systems as well as less cooling requirements. Raising summer set point temperature has good energy saving potential, in that it can be applied to both new and existing buildings. Further research and development work conducive to a better understanding of thermal comfort and energy conservation in buildings have been identified and discussed. These include (i) social-economic and cultural studies in general and post-occupancy evaluation of the built environment and the corresponding energy use in particular, and (ii) consideration of future climate scenarios in the analysis of co- and tri-generation schemes for HVAC applications, fuel mix and the associated energy planning/distribution systems in response to the expected changes in heating and cooling requirements due to climate change

  6. Thermal Condensate Structure and Cosmological Energy Density of the Universe

    Directory of Open Access Journals (Sweden)

    Antonio Capolupo

    2016-01-01

    Full Text Available The aim of this paper is to study thermal vacuum condensate for scalar and fermion fields. We analyze the thermal states at the temperature of the cosmic microwave background (CMB and we show that the vacuum expectation value of the energy momentum tensor density of photon fields reproduces the energy density and pressure of the CMB. We perform the computations in the formal framework of the Thermo Field Dynamics. We also consider the case of neutrinos and thermal states at the temperature of the neutrino cosmic background. Consistency with the estimated lower bound of the sum of the active neutrino masses is verified. In the boson sector, nontrivial contribution to the energy of the universe is given by particles of masses of the order of 10−4 eV compatible with the ones of the axion-like particles. The fractal self-similar structure of the thermal radiation is also discussed and related to the coherent structure of the thermal vacuum.

  7. Thermal condensate structure and cosmological energy density of the Universe

    CERN Document Server

    Capolupo, Antonio; Vitiello, Giuseppe

    2016-01-01

    The aim of this paper is the study of thermal vacuum condensate for scalar and fermion fields. We analyze the thermal states at the temperature of the cosmic microwave background (CMB) and we show that the vacuum expectation value of the energy momentum tensor density of photon fields reproduces the energy density and pressure of the CMB. We perform the computations in the formal framework of the thermo field dynamics. We also consider the case of neutrinos and thermal states at the temperature of the neutrino cosmic background. Consistency with the estimated lower bound of the sum of the active neutrino masses is verified. In the boson sector, non trivial contribution to the energy of the universe is given by particles of masses of the order of $10^{-4}eV$ compatible with the ones of the axion-like particles. The fractal self-similar structure of the thermal radiation is also discussed and related to the coherent structure of the thermal vacuum.

  8. Desorption Behavior of Trichloroethene and Tetrachloroethene in U.S. Department of Energy Savannah River Site Unconfined Aquifer Sediments

    Energy Technology Data Exchange (ETDEWEB)

    Riley, Robert G.; Szecsody, Jim E.; Mitroshkov, Alexandre V.; Brown, Christopher F.

    2006-06-21

    The DOE Savannah River Site (SRS) is evaluating the potential applicability of the monitored natural attenuation (MNA) process as a contributor to the understanding of the restoration of its unconfined groundwater aquifer known to be contaminated with the chlorinated hydrocarbon compounds trichloroethylene (TCE) and tetrachloroethylene (PCE). This report discusses the results from aqueous desorption experiments on SRS aquifer sediments from two different locations at the SRS (A/M Area; P-Area) with the objective of providing technically defensible TCE/PCE distribution coefficient (Kd) data and data on TCE/PCE reversible and irreversible sorption behavior needed for further MNA evaluation.

  9. Efficient thermal energy harvesting using nanoscale magnetoelectric heterostructures

    Science.gov (United States)

    Etesami, S. R.; Berakdar, J.

    2016-02-01

    Thermomechanical cycles with a ferroelectric working substance convert heat to electrical energy. As shown here, magnetoelectrically coupled ferroelectric/ferromagnetic composites (also called multiferroics) allow for an efficient thermal energy harvesting at room temperature by exploiting the pyroelectric effect. By virtue of the magnetoelectric coupling, external electric and magnetic fields can steer the operation of these heat engines. Our theoretical predictions are based on a combination of Landau-Khalatnikov-Tani approach (with a Ginzburg-Landau-Devonshire potential) to simulate the ferroelectric dynamics coupled to the magnetic dynamics. The latter is treated via the electric-polarization-dependent Landau-Lifshitz-Gilbert equation. By performing an adapted Olsen cycle we show that a multiferroic working substance is potentially much more superior to the sole ferroelectrics, as far as the thermal energy harvesting using pyroelectric effect is concerned. Our proposal holds promise not only for low-energy consuming devices but also for cooling technology.

  10. Solar-thermal energy - How can progress be made?

    International Nuclear Information System (INIS)

    This first part of a two-part series discusses the possible use of solar energy in thermal applications and their future potential. The article is based on a lecture given by professor Ueli Frei of the University of Applied Science in Rapperswil, Switzerland. The important role that solar energy will play in the substitution of conventional forms of heating energy supply is discussed. Various categories of use are described and future developments in the domestic and industrial areas are examined, including hot-water preparation, power generation and refrigeration. The Institute for Solar Technology in Rapperswil is briefly introduced and the potential for the use of solar thermal energy in Switzerland is discussed

  11. Thermal indoor environment and energy consumption in a plus-energy house: cooling season measurements

    DEFF Research Database (Denmark)

    Kazanci, Ongun Berk; Olesen, Bjarne W.

    2015-01-01

    floor cooling system) and increasing the ventilation rate provided a better thermal indoor environment but with increased energy consumption. The thermal indoor environment and energy performance of the house can be improved with decreased glazing area, increased thermal mass, installation of solar......The present study is concerned with the thermal indoor environment and HVAC system energy consumption of a detached, one-story, single family, plus-energy house during a cooling season. The house was located in Denmark and it has been used as a full-scale experimental facility for one year. The...... house was cooled by a floor cooling system and was ventilated with a mechanical ventilation system. Different operative temperature set-points and different ventilation rates were tested. Operative temperature at a representative location inside the occupied zone was used as an indicator of the thermal...

  12. Regolith thermal energy storage for lunar nighttime power

    Science.gov (United States)

    Tillotson, Brian

    1992-01-01

    A scheme for providing nighttime electric power to a lunar base is described. This scheme stores thermal energy in a pile of regolith. Any such scheme must somehow improve on the poor thermal conductivity of lunar regolith in vacuum. Two previous schemes accomplish this by casting or melting the regolith. The scheme described here wraps the regolith in a gas-tight bag and introduces a light gas to enhance thermal conductivity. This allows the system to be assembled with less energy and equipment than schemes which require melting of regolith. A point design based on the new scheme is presented. Its mass from Earth compares favorably with the mass of a regenerative fuel cell of equal capacity.

  13. Exploitation of solar energy using integrated photovoltaic and thermal systems

    OpenAIRE

    Anfruns Damians, Lluis

    2010-01-01

    Energy self-sufficiency of buildings is based on the production of heat and electricity with the systems which are integrated into the building and utilize renewable energy sources. These systems can be built as decentralized units that are simultaneously converting solar radiation into electricity and heat. Researches shows that high efficiency of both electricity and heat production can be achieved in this way. In the thesis, solutions of integrated photovoltaic and thermal systems using...

  14. Spectral and Thermal Properties of Biofield Energy Treated Cotton

    OpenAIRE

    Trivedi, Mahendra Kumar

    2015-01-01

    Cotton has widespread applications in textile industries due its interesting physicochemical properties. The objective of this study was to investigate the influence of biofield energy treatment on the spectral, and thermal properties of the cotton. The study was executed in two groups namely control and treated. The control group persisted as untreated, and the treated group received Mr. Trivedi’s biofield energy treatment. The control and treated cotton were characterized by different...

  15. New Thermal Field Electron Emission Energy Conversion Method

    Directory of Open Access Journals (Sweden)

    Ptitsin V.E.

    2012-08-01

    Full Text Available New thermal field electron emission energy conversion method for vacuum electron-optical systems (EOS with a nanostructured surface electron sources is offered and developed. Physical and numerical modeling of an electron emission and transport processes for different EOS is carried out. It is shown that at the specific configuration of electrostatic and magnetic fields in the EOS offered method permits to realize energy conversion processes with high efficiency.

  16. High Temperature Aquifer Storage

    Science.gov (United States)

    Ueckert, Martina; Niessner, Reinhard; Baumann, Thomas

    2015-04-01

    Combined heat and power generation (CHP) is highly efficient because excess heat is used for heating and/or process energy. However, the demand of heat energy varies considerably throughout the year while the demand for electrical energy is rather constant. It seems economically and ecologically highly beneficial for municipalities and large power consumers such as manufacturing plants to store excess heat in groundwater aquifers and to recuperate this energy at times of higher demand. Apart from the hydrogeological conditions, high transmissivity and favorable pressure gradients, the hydrochemical conditions are crucial for long-term operation. Within the project High Temperature Aquifer Storage, scientists investigate storage and recuperation of excess heat energy into the bavarian Malm aquifer. After one year of planning, construction, and the successful drilling of a research well to 495 m b.s.l. the first large scale heat storage test in the Malm aquifer was finished just before Christmas 2014. An enormous technical challenge was the disruption of the carbonate equilibrium - modeling results indicated a carbonate precipitation of 10-50 kg/d in the heat exchangers. The test included five injection pulses of hot water (60 °C up to 110 °C) and four tracer pulses, each consisting of a reactive and a conservative fluorescent dye. Injection and production rates were 15 L/s. About 4 TJ of heat energy were necessary to achieve the desired water temperatures. Electrical conductivity, pH and temperature were recorded at a bypass where also samples were taken. A laboratory container at the drilling site was equipped for the analysis of the concentration of the tracers and the cation concentrations at sampling intervals of down to 15 minutes. Additional water samples were taken and analyzed for major ions and trace elements in the laboratory. The disassembled heat exchanger proved that precipitation was successfully prevented by adding CO2 to the water before heating

  17. Thermal energy storage using thermo-chemical heat pump

    International Nuclear Information System (INIS)

    Highlights: ► Understanding of the performance of thermo chemical heat pump. ► Tool for storing thermal energy. ► Parameters that affect the amount of thermal stored energy. ► Lithium chloride has better effect on storing thermal energy. - Abstract: A theoretical study was performed to investigate the potential of storing thermal energy using a heat pump which is a thermo-chemical storage system consisting of water as sorbet, and sodium chloride as the sorbent. The effect of different parameters namely; the amount of vaporized water from the evaporator, the system initial temperature and the type of salt on the increase in temperature of the salt was investigated and hence on the performance of the thermo chemical heat pump. It was found that the performance of the heat pump improves with the initial system temperature, with the amount of water vaporized and with the water remaining in the system. Finally it was also found that lithium chloride salt has higher effect on the performance of the heat pump that of sodium chloride.

  18. Solar Program Assessment: Environmental Factors - Ocean Thermal Energy Conversion.

    Science.gov (United States)

    Energy Research and Development Administration, Washington, DC. Div. of Solar Energy.

    This report presents the environmental problems which may arise with the further development of Ocean Thermal Energy Conversion, one of the eight Federally-funded solar technologies. To provide a background for this environmental analysis, the history and basic concepts of the technology are reviewed, as are its economic and resource requirements.…

  19. Metal hydrides based high energy density thermal battery

    Energy Technology Data Exchange (ETDEWEB)

    Fang, Zhigang Zak, E-mail: zak.fang@utah.edu [Department of Metallurgical Engineering, The University of Utah, 135 South 1460 East, Room 412, Salt Lake City, UT 84112-0114 (United States); Zhou, Chengshang; Fan, Peng [Department of Metallurgical Engineering, The University of Utah, 135 South 1460 East, Room 412, Salt Lake City, UT 84112-0114 (United States); Udell, Kent S. [Department of Metallurgical Engineering, The University of Utah, 50 S. Central Campus Dr., Room 2110, Salt Lake City, UT 84112-0114 (United States); Bowman, Robert C. [Department of Metallurgical Engineering, The University of Utah, 135 South 1460 East, Room 412, Salt Lake City, UT 84112-0114 (United States); Vajo, John J.; Purewal, Justin J. [HRL Laboratories, LLC, 3011 Malibu Canyon Road, Malibu, CA 90265 (United States); Kekelia, Bidzina [Department of Metallurgical Engineering, The University of Utah, 50 S. Central Campus Dr., Room 2110, Salt Lake City, UT 84112-0114 (United States)

    2015-10-05

    Highlights: • The principle of the thermal battery using advanced metal hydrides was demonstrated. • The thermal battery used MgH{sub 2} and TiMnV as a working pair. • High energy density can be achieved by the use of MgH{sub 2} to store thermal energy. - Abstract: A concept of thermal battery based on advanced metal hydrides was studied for heating and cooling of cabins in electric vehicles. The system utilized a pair of thermodynamically matched metal hydrides as energy storage media. The pair of hydrides that was identified and developed was: (1) catalyzed MgH{sub 2} as the high temperature hydride material, due to its high energy density and enhanced kinetics; and (2) TiV{sub 0.62}Mn{sub 1.5} alloy as the matching low temperature hydride. Further, a proof-of-concept prototype was built and tested, demonstrating the potential of the system as HVAC for transportation vehicles.

  20. Fuels and chemicals from biomass using solar thermal energy

    Science.gov (United States)

    Giori, G.; Leitheiser, R.; Wayman, M.

    1981-01-01

    The significant nearer term opportunities for the application of solar thermal energy to the manufacture of fuels and chemicals from biomass are summarized, with some comments on resource availability, market potential and economics. Consideration is given to the production of furfural from agricultural residues, and the role of furfural and its derivatives as a replacement for petrochemicals in the plastics industry.

  1. Thermal energy storage subsystems. A collection of quarterly reports

    Science.gov (United States)

    1978-01-01

    The design, development, and progress toward the delivery of three subsystems is discussed. The subsystem used a salt hydrate mixture for thermal energy storage. The program schedules, technical data, and other program activities from October 1, 1976, through December 31, 1977 are presented.

  2. Survey of solar thermal energy storage subsystems for thermal/electric applications

    Energy Technology Data Exchange (ETDEWEB)

    Segaser, C. L.

    1978-08-01

    A survey of the current technology and estimated costs of subsystems for storing the thermal energy produced by solar collectors is presented. The systems considered were capable of producing both electricity and space conditioning for three types of loads: a single-family detached residence, an apartment complex of 100 units, and a city of 30,000 residents, containing both single-family residences and apartments. Collector temperatures will be in four ranges: (1) 100 to 250/sup 0/F (used for space heating and single-cycle air conditioners and organic Rankine low-temperature turbines); (2) 300 to 400/sup 0/F (used for dual-cycle air conditioners and low-temperature turbines); (3) 400 to 600/sup 0/F (using fluids from parabolic trough collectors to run Rankine turbines); (4) 800 to 1000/sup 0/F (using fluids from heliostats to run closed-cycle gas turbines and steam Rankine turbines). The solar thermal energy subsystems will require from 60 to 36 x 10/sup 5/ kWhr (2.05 x 10/sup 5/ to 1.23 x 10/sup 10/ Btu) of thermal storage capacity. In addition to sensible heat and latent heat storage materials, several other media were investigated as potential thermal energy storage materials, including the clathrate and semiclathrate hydrates, various metal hydrides, and heat storage based on inorganic chemical reactions.

  3. Experimental measurements of thermal properties of high-temperature refractory materials used for thermal energy storage

    Science.gov (United States)

    El-Leathy, Abdelrahman; Jeter, Sheldon; Al-Ansary, Hany; Abdel-Khalik, Said; Golob, Matthew; Danish, Syed Noman; Saeed, Rageh; Djajadiwinata, Eldwin; Al-Suhaibani, Zeyad

    2016-05-01

    This paper builds on studies conducted on thermal energy storage (TES) systems that were built as a part of the work performed for a DOE-funded SunShot project titled "High Temperature Falling Particle Receiver". In previous studies, two small-scale TES systems were constructed for measuring heat loss at high temperatures that are compatible with the falling particle receiver concept, both of which had shown very limited heat loss. Through the course of those studies, it became evident that there was a lack of information about the thermal performance of some of the insulating refractory materials used in the experiments at high temperatures, especially insulating firebrick and perlite concrete. This work focuses on determining the thermal conductivities of those materials at high temperatures. The apparatus consists of a prototype cylindrical TES bin built with the same wall construction used in previous studies. An electric heater is placed along the centerline of the bin, and thermocouples are used to measure temperature at the interfaces between all layers. Heat loss is measured across one of the layers whose thermal conductivity had already been well established using laboratory experiments. This value is used to deduce the thermal conductivity of other layers. Three interior temperature levels were considered; namely, 300°C, 500°C, and 700°C. Results show that the thermal conductivity of insulating firebrick remains low (approximately 0.22 W/m.K) at an average layer temperature as high as 640°C, but it was evident that the addition of mortar had an impact on its effective thermal conductivity. Results also show that the thermal conductivity of perlite concrete is very low, approximately 0.15 W/m.K at an average layer temperature of 360°C. This is evident by the large temperature drop that occurs across the perlite concrete layer. These results should be useful for future studies, especially those that focus on numerical modeling of TES bins.

  4. Thermal modeling with solid/liquid phase change of the thermal energy storage experiment

    Science.gov (United States)

    Skarda, J. Raymond Lee

    1991-01-01

    A thermal model which simulates combined conduction and phase change characteristics of thermal energy storage (TES) materials is presented. Both the model and results are presented for the purpose of benchmarking the conduction and phase change capabilities of recently developed and unvalidated microgravity TES computer programs. Specifically, operation of TES-1 is simulated. A two-dimensional SINDA85 model of the TES experiment in cylindrical coordinates was constructed. The phase change model accounts for latent heat stored in, or released from, a node undergoing melting and freezing.

  5. High Temperature Aquifer Storage

    Science.gov (United States)

    Ueckert, Martina; Niessner, Reinhard; Baumann, Thomas

    2016-04-01

    Combined heat and power generation (CHP) is highly efficient because excess heat is used for heating and/or process energy. However, the demand of heat energy varies considerably throughout the year while the demand for electrical energy is rather constant. It seems economically and ecologically highly beneficial for municipalities and large power consumers such as manufacturing plants to store excess heat in groundwater aquifers and to recuperate this energy at times of higher demand. Within the project High Temperature Aquifer Storage, scientists investigate storage and recuperation of excess heat energy into the bavarian Malm aquifer. Apart from high transmissivity and favorable pressure gradients, the hydrochemical conditions are crucial for long-term operation. An enormous technical challenge is the disruption of the carbonate equilibrium - modeling results indicated a carbonate precipitation of 10 - 50 kg/d in the heat exchangers. The test included five injection pulses of hot water (60 °C up to 110 °C) and four tracer pulses, each consisting of a reactive and a conservative fluorescent dye, into a depth of about 300 m b.s.l. resp. 470 m b.s.l. Injection and production rates were 15 L/s. To achieve the desired water temperatures, about 4 TJ of heat energy were necessary. Electrical conductivity, pH and temperature were recorded at a bypass where also samples were taken. A laboratory container at the drilling site was equipped for analysing the concentration of the dyes and the major cations at sampling intervals of down to 15 minutes. Additional water samples were taken and analysed in the laboratory. The disassembled heat exchanger prooved that precipitation was successfully prevented by adding CO2 to the water before heating. Nevertheless, hydrochemical data proved both, dissolution and precipitation processes in the aquifer. This was also suggested by the hydrochemical modelling with PhreeqC and is traced back to mixture dissolution and changing

  6. Thermal Storage Systems Assessment for Energy Sustainability in Housing Units

    Directory of Open Access Journals (Sweden)

    Tania I. Lagunes Vega

    2016-04-01

    Full Text Available In order to achieve greater enhancements in energy sustainability for housing, the function and efficiency of two different passive cooling systems were studied: encapsulated water in recycled bottles of Polyethylene terephthalate (PET and polystyrene plates, in comparison with standard concrete slab systems, which are customarily used in housing. Experiments were placed over a tile surface, in which temperature changes were monitored for a period of 20 days from 08:00 to 20:00. The efficiency of passive thermal storage systems was endorsed through statistical analysis using the “SPSS” software. This resulted in a 17% energy saving, thus promoting energy sustainability in housing units, which reduces the use of electrical appliances required to stabilize conditions to achieve optimum thermal comfort for the human body inside a house, therefore, reducing electrical power consumption, CO2 emissions to the atmosphere and generating savings. Due to the complexity of a system with temperature changes, a fractal analysis was performed for each experimental system, using the “Benoit” software (V.1.3 with self-compatible tools of rescaled range (R/S and a wavelets method, showing that the thermal fluctuations on the tiles with the thermal storage system adapt to the rescaled range analysis and the regular tiles adapt to the wavelets method.

  7. Energy-Dependent Timing of Thermal Emission in Solar Flares

    OpenAIRE

    Jain, Rajmal; Awasthi, Arun Kumar; Rajpurohit, Arvind Singh; Aschwanden, Markus J.

    2011-01-01

    We report solar flare plasma to be multi-thermal in nature based on the theoretical model and study of the energy-dependent timing of thermal emission in ten M-class flares. We employ high-resolution X-ray spectra observed by the Si detector of the "Solar X-ray Spectrometer" (SOXS). The SOXS onboard the Indian GSAT-2 spacecraft was launched by the GSLV-D2 rocket on 8 May 2003. Firstly we model the spectral evolution of the X-ray line and continuum emission flux F(\\epsilon) from the flare by i...

  8. Thermal neutron capture cross-sections and neutron separation energies

    International Nuclear Information System (INIS)

    Thermal radiative neutron capture cross-sections have been re-evaluated as part of an ongoing project at the National Nuclear Data Center at Brookhaven National Laboratory at Upton, New York, to update the Neutron Cross-sections compendia, Vol. 1, Parts A and B, Neutron Resonance Parameters and Thermal Capture Cross-sections, published by Academic Press in 1981 and 1984, respectively. Neutron separation energies are evaluated as part of an ongoing project at the Atomic Mass Data Center in Orsay, France. The adopted data are compared with new results derived from this evaluation

  9. Nanoparticles for heat transfer and thermal energy storage

    Energy Technology Data Exchange (ETDEWEB)

    Singh, Dileep; Cingarapu, Sreeram; Timofeeva, Elena V.; Moravek, Michael

    2015-07-14

    An article of manufacture and method of preparation thereof. The article of manufacture and method of making the article includes an eutectic salt solution suspensions and a plurality of nanocrystalline phase change material particles having a coating disposed thereon and the particles capable of undergoing the phase change which provides increase in thermal energy storage. In addition, other articles of manufacture can include a nanofluid additive comprised of nanometer-sized particles consisting of copper decorated graphene particles that provide advanced thermal conductivity to heat transfer fluids.

  10. Thermal comfort and energy-efficient cooling of nonresidential buildings

    CERN Document Server

    Kalz, Doreen

    2014-01-01

    This book supports HVAC planners in reducing the cooling energy demand, improving the indoor environment and designing more cost-effective building concepts. High performance buildings have shown that it is possible to go clearly beyond the energy requirements of existing legislation and obtaining good thermal comfort. However, there is still a strong uncertainty in day-to-day practice due to the lack of legislative regulations for mixed-mode buildings which are neither only naturally ventilated nor fully air-conditioned, but use a mix of different low-energy cooling techniques. Based on the f

  11. Wave Energy Conversion and Ocean Thermal Energy Conversion Potential in Developing Member Countries

    OpenAIRE

    Asian Development Bank

    2014-01-01

    Wave energy conversion (WEC) and Ocean thermal energy conversion (OTEC) are two potentially significant sources of renewable energy that are available to help the Asian Development Bank’s (ADB) developing member countries (DMCs) reduce their dependence on fossil-fuel based energy generation and bolster energy security. This report summarizes WEC and OTEC information that is available in the public domain for the DMCsand assesses the viability of using these resources to produce electricity. I...

  12. Electrical characterization of a buckling thermal energy harvester

    Science.gov (United States)

    Trioux, E.; Rufer, L.; Monfray, S.; Skotnicki, T.; Muralt, P.; Basrour, S.

    2015-12-01

    This paper presents the electrical characterizations of a novel concept for thermal energy harvesting at micro scale. The devices presented here are based on a two-step transduction combining thermo-mechanical and piezoelectric conversion. The piezoelectric layer is directly integrated into a buckling bilayer plate made of aluminium and aluminium nitride. For the first time, we have characterized the structures electrically and we have investigated their output power during the buckling. Firstly, we have used an insulating tip to make the plate buckle in order to have an estimation of the output power due to piezoelectric contribution only, and to eliminate any pyroelectric contribution that might be present during the thermal actuation. Then, we heated up the structure and we collected the output signal with an instrumentation amplifier in order to measure the voltage generated during the buckling. The output power during the mechanical and the thermal buckling is compared in the paper.

  13. Scenarios for solar thermal energy applications in Brazil

    International Nuclear Information System (INIS)

    The Solar and Wind Energy Resource Assessment (SWERA) database is used to prepare and discuss scenarios for solar thermal applications in Brazil. The paper discusses low temperature applications (small and large scale water heating) and solar power plants for electricity production (concentrated solar power plants and solar chimney plants) in Brazil. The results demonstrate the feasibility of large-scale application of solar energy for water heating and electricity generation in Brazil. Payback periods for water heating systems are typically below 4 years if they were used to replace residential electric showerheads in low-income families. Large-scale water heating systems also present high feasibility and many commercial companies are adopting this technology to reduce operational costs. The best sites to set up CSP plants are in the Brazilian semi-arid region where the annual energy achieves 2.2 MW h/m2 and averages of daily solar irradiation are larger than 5.0 kW h/m2/day. The western area of Brazilian Northeastern region meets all technical requirements to exploit solar thermal energy for electricity generation based on solar chimney technology. Highlights: ► Scenarios for solar thermal applications are presented. ► Payback is typically below 4 years for small scale water heating systems. ► Large-scale water heating systems also present high feasibility. ► The Brazilian semi-arid region is the best sites for CSP and chimney tower plants.

  14. Advances in Thermal Insulation. Vacuum Insulation Panels and Thermal Efficiency to Reduce Energy Usage in Buildings

    Energy Technology Data Exchange (ETDEWEB)

    Thorsell, Thomas

    2012-07-01

    We are coming to realize that there is an urgent need to reduce energy usage in buildings and it has to be done in a sustainable way. This thesis focuses on the performance of the building envelope; more precisely thermal performance of walls and super insulation material in the form of vacuum insulation. However, the building envelope is just one part of the whole building system, and super insulators have one major flaw: they are easily adversely affected by other problems in the built environment. Vacuum Insulation Panels are one fresh addition to the arsenal of insulation materials available to the building industry. They are composite material with a core and an enclosure which, as a composite, can reach thermal conductivities as low as 0.004 W/(mK). However, the exceptional performance relies on the barrier material preventing gas permeation, maintaining a near vacuum into the core and a minimized thermal bridge effect from the wrapping of barrier material round the edge of a panel. A serpentine edge is proposed to decrease the heat loss at the edge. Modeling and testing shows a reduction of 60 % if a reasonable serpentine edge is used. A diffusion model of permeation through multilayered barrier films with metallization coatings was developed to predict ultimate service life. The model combines numerical calculations with analytical field theory allowing for more precise determination than current models. The results using the proposed model indicate that it is possible to manufacture panels with lifetimes exceeding 50 years with existing manufacturing. Switching from the component scale to the building scale; an approach of integrated testing and modeling is proposed. Four wall types have been tested in a large range of environments with the aim to assess the hydrothermal nature and significance of thermal bridges and air leakages. The test procedure was also examined as a means for a more representative performance indicator than R-value (in USA). The

  15. ATES Contribution to the Housing Energy Balance: a Simple Assessment Methodology Contribution du stockage d’énergie thermique en aquifère au bilan énergétique lié à l’habitat : méthodologie d’évaluation rapide

    Directory of Open Access Journals (Sweden)

    Bourbiaux B.

    2011-02-01

    Full Text Available The reduction of Green-House Gas Emissions (GHGE goes through a sum of solutions that need to be tuned to the local context in terms of energy needs and resources, and also to the demand and offer variations with time. The housing heat consumption is particularly concerned as it is seasonal and rarely in phase with the deliverability of alternative or renewable energy sources. This paper studies heat storage in saline untapped aquifers as a solution to overcome the time lag between production and consumption. This process applies to heat networks that supply dense housing complexes. Firstly, a methodology is described to size an Aquifer Thermal Energy Storage (ATES project as a function of the heat production and consumption characteristics on the one hand, and of the recovery factor of the stored heat on the other hand. The major role played by this recovery factor leads to a review of thermal losses of various origins and to a sensitivity study of influent reservoir parameters such as the aquifer thickness, productivity and heterogeneity, for the purpose of aquifer selection and storage project management. La reduction des Gaz a Effet de Serre (GES passe par un ensemble de solutions qui doivent etre adaptees au contexte local des besoins et ressources en energie, ainsi qu’aux variations de l’offre et la demande au cours du temps. Ce constat concerne en particulier la consommation d’energie calorifique destinee a l’habitat. En effet, cette consommation de chaleur est saisonniere et rarement en phase avec la disponibilite des sources d’energie alternatives ou renouvelables. Cet article etudie le stockage de chaleur dans des aquiferes salins inexploites en tant que solution pour pallier ce dephasage entre production et consommation. Ce procede concerne les reseaux de chaleur desservant un habitat concentre. En premier lieu, une methodologie quantitative est decrite pour dimensionner le projet de stockage d’energie thermique en

  16. Temperature-induced impacts on groundwater quality and arsenic mobility in anoxic aquifer sediments used for both drinking water and shallow geothermal energy production.

    Science.gov (United States)

    Bonte, Matthijs; van Breukelen, Boris M; Stuyfzand, Pieter J

    2013-09-15

    Aquifers used for the production of drinking water are increasingly being used for the generation of shallow geothermal energy. This causes temperature perturbations far beyond the natural variations in aquifers and the effects of these temperature variations on groundwater quality, in particular trace elements, have not been investigated. Here, we report the results of column experiments to assess the impacts of temperature variations (5°C, 11°C, 25°C and 60°C) on groundwater quality in anoxic reactive unconsolidated sandy sediments derived from an aquifer system widely used for drinking water production in the Netherlands. Our results showed that at 5 °C no effects on water quality were observed compared to the reference of 11°C (in situ temperature). At 25°C, As concentrations were significantly increased and at 60 °C, significant increases were observed pH and DOC, P, K, Si, As, Mo, V, B, and F concentrations. These elements should therefore be considered for water quality monitoring programs of shallow geothermal energy projects. No consistent temperature effects were observed on Na, Ca, Mg, Sr, Fe, Mn, Al, Ba, Co, Cu, Ni, Pb, Zn, Eu, Ho, Sb, Sc, Yb, Ga, La, and Th concentrations, all of which were present in the sediment. The temperature-induced chemical effects were probably caused by (incongruent) dissolution of silicate minerals (K and Si), desorption from, and potentially reductive dissolution of, iron oxides (As, B, Mo, V, and possibly P and DOC), and mineralisation of sedimentary organic matter (DOC and P). PMID:23870436

  17. Thermal Energy in Carbon Nanotube and Graphene Composite Materials

    Science.gov (United States)

    Schiffres, Scott N.

    Low-dimensional materials, like carbon nanotubes (CNTs) and graphene, possess extraordinary properties---higher thermal conductivity than any bulk material, mechanical strength 10-100 times greater than steel on a mass basis, and electrical current capacity 1000 times greater than copper. While composites incorporating these low-dimensional materials promise solutions to global sustainability challenges, significant transport barriers exist at the matrix interface that influence the composite properties. My PhD research sought to address this knowledge gap. I've experimentally explored how CNTs and graphene impact thermal conductivity when added in small volume fractions to gases, liquids and solids through the study of CNT aerogels (ultra lightweight, 8 kg/m3, 99.6% void space), and phase change nanocomposites (hexadecane-graphene). I measured the thermal conductivity of the CNT aerogel with various filling gases versus pressure using a novel technique that targeted ultralow thermal conductivity materials, called metal-coated 3o. I observed amplified energy transport length scales resulting from low gas accommodation, which is a general feature of carbon based nanoporous materials. Our evidence also shows that despite the high thermal conductivity of CNTs, thermal conduction through the CNT network is limited by the high thermal boundary resistance at van der Waals bonded CNT junctions. In the second system, I studied thermal and electrical conductivity of hexadecane- multi-layered-graphene (MLG) phase change nanocomposites to understand how morphology of the MLG network impacts transport. By adjusting the freezing rate, the electrical conductivity in the solid phase can be tuned between 1 and 5 orders-of-magnitude and the solid-liquid thermal conductivity ratio can be varied between 2.6 to 3.0. This research has yielded interesting insights into the tunability of nanocomposites and the physics underlying it, including evidence to indicate that the presence of

  18. Compressed Air Energy Storage Using Saline Aquifer as Storage Reservior%压缩空气地下咸水含水层储能技术

    Institute of Scientific and Technical Information of China (English)

    胡贤贤; 张可霓; 郭朝斌

    2014-01-01

    Energy crisis and greenhouse effect have promoted the utilization of renewable energy. Energy storage technology is an indispensable part in solving the fluctuation problem for the utilization of solar energy, wind energy, etc. Compressed air energy storage (CAES) technology is the second large energy storage potential just after the pumped hydro storage technology. At present, reservoirs for the CAES are usually underground caverns which are highly limited by geological conditions. Using saline aquifer as the storage reservoir can extend the utilization of the CAES. Herein, the operation principle, advantages and disadvantages of CAES plant are introduced. The feasibility, problems and the key technologies used in aquifer CAES such as the residual hydrocarbons, oxidation, corrosion, particulates and the choice of cushion gas are discussed. This study concludes that the use of saline aquifer as storage reservoir will be an important way to extend the application of CAES.%能源危机和温室效应促进了可再生能源的利用,储能技术是解决太阳能、风能波动问题的重要手段。压缩空气储能(Compressed Air Energy Storage, CAES)技术是仅次于抽水蓄能的第二大蓄能技术。目前CAES多是通过洞穴实现,其主要缺点是对地质要求较高,合适的洞穴数量有限,为扩大其应用,可使用地下咸水含水层作为储层。本文介绍了 CAES 电站的工作原理、优缺点及各国的发展现状,并分析了利用地下咸水含水层进行压缩空气储能的可行性、优点及一些问题与技术方法,如储层内残余烃的影响、氧化与腐蚀作用、颗粒的影响及缓冲气的选择,表明含水层CAES将是拓宽CAES应用的重要途径。

  19. Thermal transport measurements in high-energy-density matter

    Science.gov (United States)

    Ping, Yuan

    2015-11-01

    Thermal conductivity is one of the most fundamental physical properties of matter. It determines the heat transport rate and has an enormous impact on a variety of mechanical, electrical, chemical, and nuclear systems. Thermal conduction is important in high energy density (HED) matter such as laboratory fusion plasmas, planetary cores, compact stars, and other celestial objects. Examples are in the ablation and instability growth in inertial confinement fusion (ICF) capsules, in energy loss from ICF hot spot, and in the evolution of Earth's core-mantle boundary. Despite the importance of thermal conductivity in HED systems, experimental measurements under relevant conditions are scarce and challenging. We have developed a method of differential heating for thermal conductivity measurements. In this talk, experimental designs will be described for four different platforms: optical laser heating, proton heating, laser-generated x-ray heating and XFEL heating. Data from various facilities will be presented and comparison with models will be discussed. This work was performed under DOE contract DE-AC52-07NA27344 with support from OFES Early Career program and LLNL LDRD program.

  20. Thermal stability evaluation of palm oil as energy transport media

    International Nuclear Information System (INIS)

    The thermal stability of palm oil as energy transport media in a hydraulic system was studied. The oils were aged by circulating the oil in an open loop hydraulic system at an isothermal condition of 55 deg. C for 600 h. The thermal behavior and kinetic parameters of fresh and degraded palm oil, with and without oxidation inhibitor, were studied using the dynamic heating rate mode of a thermogravimetric analyser (TGA). Viscometric properties, total acid number and iodine value analyses were used to complement the TGA data. The thermodynamic parameter of activation energy of the samples was determined by direct Arrhenius plot and integral methods. The results may have important applications in the development of palm oil based hydraulic fluid. The results were compared with commercial vegetable based hydraulic fluid. The use of F10 and L135 additives was found to suppress significantly the increase of acid level and viscosity of the fluid

  1. An assessment methodology for thermal energy storage evaluation

    Energy Technology Data Exchange (ETDEWEB)

    Brown, D.R.; Dirks, J.A.; Drost, M.K.; Spanner, G.E.; Williams, T.A.

    1987-11-01

    This report documents an assessment methodology for evaluating the cost, performance, and overall economic feasibility of thermal energy storage (TES) concepts. The methodology was developed by Thermal Energy Storage Evaluation Program personnel at Pacific Northwest Laboratory (PNL) for use by PNL and other TES concept evaluators. The methodology is generically applicable to all TES concepts; however, specific analyses may require additional or more detailed definition of the ground rules, assumptions, and analytical approach. The overall objective of the assessment methodology is to assist in preparing equitable and proper evaluations of TES concepts that will allow developers and end-users to make valid decisions about research and development (R and D) and implementation. The methodology meets this objective by establishing standard approaches, ground rules, assumptions, and definitions that are analytically correct and can be consistently applied by concept evaluators. 15 refs., 4 figs., 13 tabs.

  2. REVIEW OF SOLAR COOKER WITH INTEGRATED THERMAL ENERGY STORAGE

    OpenAIRE

    Sandesh P. Gotekar; Atul S. Tumane

    2014-01-01

    Solar thermal energy finds its simplest application in the form of solar cooking, which in itself has enormous potential for reducing dependence on conventional fuel seen the domestic sector. The different types of solar cookers developed for cooking are a box type, a concentrator type and an indirect type. The detailed design, test procedures, theory and utility of solar cookers are studied in this paper. An integrated solar cooker uses a fluid to transfer heat from solar coll...

  3. Thermal, Spectroscopic and Chemical Characterization of Biofield Energy Treated Anisole

    OpenAIRE

    Trivedi, Mahendra Kumar

    2015-01-01

    The objective of the present study was to evaluate the impact of biofield energy treatment on the thermal, spectroscopic, and chemical properties of anisole by various analytical methods such as gas chromatography-mass spectrometry (GC-MS), high performance liquid chromatography (HPLC), differential scanning calorimetry (DSC), Fourier transform infrared (FT-IR) spectroscopy, and ultraviolet-visible (UV-Vis) spectroscopy. The anisole sample was divided into two parts, control and treated. The ...

  4. Ocean Thermal Energy Conversion (OTEC) program. FY 1977 program summary

    Energy Technology Data Exchange (ETDEWEB)

    None

    1978-01-01

    An overview is given of the ongoing research, development, and demonstration efforts. Each of the DOE's Ocean Thermal Energy Conversion projects funded during fiscal year 1977 (October 1, 1976 through September 30, 1977) is described and each project's status as of December 31, 1977 is reflected. These projects are grouped as follows: program support, definition planning, engineering development, engineering test and evaluation, and advanced research and technology. (MHR)

  5. Energy expansion planning by considering electrical and thermal expansion simultaneously

    International Nuclear Information System (INIS)

    Highlights: • This paper focused on the expansion planning optimization of energy systems. • Employing two form of energy: the expansion of electrical and thermal energies. • The main objective is to minimize the costs. • A new Modified Honey Bee Mating Optimization (MHBMO) algorithm is applied. - Abstract: This study focused on the expansion planning optimization of energy systems employing two forms of energy: the expansion of electrical and thermal energies simultaneously. The main objective of this investigation is confirming network adequacy by adding new equipment to the network, over a given planning horizon. The main objective of the energy expansion planning (EEP) is to minimize the real energy loss, voltage deviation and the total cost of installation equipments. Since the objectives are different and incommensurable, it is difficult to solve the problem by the conventional approaches that may optimize a single objective. So, the meta-heuristic algorithm is applied to this problem. Here, Honey Bee Mating Optimization algorithm (HBMO) as a new evolutionary optimization algorithm is utilized. In order to improve the total ability of HBMO for the global search and exploration, a new modification process is suggested such a way that the algorithm will search the total search space globally. Also, regarding the uncertainties of the new complicated energy systems, in this paper for the first time, the EEP problem is investigated in a stochastic environment by the use of probabilistic load flow technique based on Point Estimate Method (PEM). In order to evaluate the feasibility and effectiveness of the proposed algorithm, two modified test systems are used as case studies

  6. Flexible hybrid energy cell for simultaneously harvesting thermal, mechanical, and solar energies.

    Science.gov (United States)

    Yang, Ya; Zhang, Hulin; Zhu, Guang; Lee, Sangmin; Lin, Zong-Hong; Wang, Zhong Lin

    2013-01-22

    We report the first flexible hybrid energy cell that is capable of simultaneously or individually harvesting thermal, mechanical, and solar energies to power some electronic devices. For having both the pyroelectric and piezoelectric properties, a polarized poly(vinylidene fluoride) (PVDF) film-based nanogenerator (NG) was used to harvest thermal and mechanical energies. Using aligned ZnO nanowire arrays grown on the flexible polyester (PET) substrate, a ZnO-poly(3-hexylthiophene) (P3HT) heterojunction solar cell was designed for harvesting solar energy. By integrating the NGs and the solar cells, a hybrid energy cell was fabricated to simultaneously harvest three different types of energies. With the use of a Li-ion battery as the energy storage, the harvested energy can drive four red light-emitting diodes (LEDs). PMID:23199138

  7. Thermal energy conversion by coupled shape memory and piezoelectric effects

    International Nuclear Information System (INIS)

    This work gives experimental evidence of a promising method of thermal-to-electric energy conversion by coupling shape memory effect (SME) and direct piezoelectric effect (DPE) for harvesting quasi-static ambient temperature variations. Two original prototypes of thermal energy harvesters have been fabricated and tested experimentally. The first is a hybrid laminated composite consisting of TiNiCu shape memory alloy (SMA) and macro fiber composite piezoelectric. This composite comprises 0.1 cm3 of active materials and harvests 75 µJ of energy for each temperature variation of 60 °C. The second prototype is a SME/DPE ‘machine’ which uses the thermally induced linear strains of the SMA to bend a bulk PZT ceramic plate through a specially designed mechanical structure. The SME/DPE ‘machine’ with 0.2 cm3 of active material harvests 90 µJ over a temperature increase of 35 °C (60 µJ when cooling). In contrast to pyroelectric materials, such harvesters are also compatible with both small and slow temperature variations. (paper)

  8. Thermal energy conversion by coupled shape memory and piezoelectric effects

    Science.gov (United States)

    Zakharov, Dmitry; Lebedev, Gor; Cugat, Orphee; Delamare, Jerome; Viala, Bernard; Lafont, Thomas; Gimeno, Leticia; Shelyakov, Alexander

    2012-09-01

    This work gives experimental evidence of a promising method of thermal-to-electric energy conversion by coupling shape memory effect (SME) and direct piezoelectric effect (DPE) for harvesting quasi-static ambient temperature variations. Two original prototypes of thermal energy harvesters have been fabricated and tested experimentally. The first is a hybrid laminated composite consisting of TiNiCu shape memory alloy (SMA) and macro fiber composite piezoelectric. This composite comprises 0.1 cm3 of active materials and harvests 75 µJ of energy for each temperature variation of 60 °C. The second prototype is a SME/DPE ‘machine’ which uses the thermally induced linear strains of the SMA to bend a bulk PZT ceramic plate through a specially designed mechanical structure. The SME/DPE ‘machine’ with 0.2 cm3 of active material harvests 90 µJ over a temperature increase of 35 °C (60 µJ when cooling). In contrast to pyroelectric materials, such harvesters are also compatible with both small and slow temperature variations.

  9. Semi-flexible bimetal-based thermal energy harvesters

    International Nuclear Information System (INIS)

    This paper introduces a new semi-flexible device able to turn thermal gradients into electricity by using a curved bimetal coupled to an electret-based converter. In fact, a two-step conversion is carried out: (i) a curved bimetal turns the thermal gradient into a mechanical oscillation that is then (ii) converted into electricity thanks to an electrostatic converter using electrets in Teflon®. The semi-flexible and low-cost design of these new energy converters pave the way to mass production over large areas of thermal energy harvesters. Raw output powers up to 13.46 μW per device were reached on a hot source at 60 °C with forced convection. Then, a DC-to-DC flyback converter has been sized to turn the energy harvesters’ raw output powers into a viable supply source for an electronic circuit (DC-3 V). At the end, 10 μW of directly usable output power were reached with 3 devices, which is compatible with wireless sensor network powering applications. (paper)

  10. Semi-flexible bimetal-based thermal energy harvesters

    CERN Document Server

    Boisseau, S; Monfray, S; Puscasu, O; Skotnicki, T; 10.1088/0964-1726/22/2/025021

    2013-01-01

    This paper introduces a new semi-flexible device able to turn thermal gradients into electricity by using a curved bimetal coupled to an electret-based converter. In fact, a two-steps conversion is carried out: (i) a curved bimetal turns the thermal gradient into a mechanical oscillation that is then (ii) converted into electricity thanks to an electrostatic converter using electrets in Teflon (r). The semi-flexible and low cost design of these new energy converters pave the way to mass production over large areas of thermal energy harvesters. Raw output powers up to 13.46uW per device were reached on a hot source at 60{\\deg}C and forced convection. Then, a DC-to-DC flyback converter has been sized to turn the energy harvesters' raw output powers into a viable supply source for an electronic circuit (DC-3V). At the end, 10uW of directly usable output power were reached with 3 devices, which is compatible with Wireless Sensor Networks powering applications. Please cite as : S Boisseau et al 2013 Smart Mater. S...

  11. Thermal energy storage for industrial waste heat recovery

    Science.gov (United States)

    Hoffman, H. W.; Kedl, R. J.; Duscha, R. A.

    1978-01-01

    The potential is examined for waste heat recovery and reuse through thermal energy storage in five specific industrial categories: (1) primary aluminum, (2) cement, (3) food processing, (4) paper and pulp, and (5) iron and steel. Preliminary results from Phase 1 feasibility studies suggest energy savings through fossil fuel displacement approaching 0.1 quad/yr in the 1985 period. Early implementation of recovery technologies with minimal development appears likely in the food processing and paper and pulp industries; development of the other three categories, though equally desirable, will probably require a greater investment in time and dollars.

  12. Thermal effects on parallel resonance energy of whistler mode wave

    Indian Academy of Sciences (India)

    Devendraa Siingh; Shubha Singh; R P Singh

    2006-02-01

    In this short communication, we have evaluated the effect of thermal velocity of the plasma particles on the energy of resonantly interacting energetic electrons with the propagating whistler mode waves as a function of wave frequency and -value for the normal and disturbed magnetospheric conditions. During the disturbed conditions when the magnetosphere is depleted in electron density, the resonance energy of the electron enhances by an order of magnitude at higher latitudes, whereas the effect is small at low latitudes. An attempt is made to explain the enhanced wave activity observed during magnetic storm periods.

  13. Energy storage and thermal control system design status

    Science.gov (United States)

    Simons, Stephen N.; Willhoite, Bryan C.; Vanommering, Gert

    1989-01-01

    The Space Station Freedom electric power system (EPS) will initially rely on photovoltaics for power generation and Ni/H2 batteries for electrical energy storage. The current design for and the development status of two major subsystems in the PV Power Module is discussed. The energy storage subsystem comprised of high capacity Ni/H2 batteries and the single-phase thermal control system that rejects the excess heat generated by the batteries and other components associated with power generation and storage is described.

  14. Thermionic emission energy distribution from nanocrystalline diamond films for direct thermal-electrical energy conversion applications

    OpenAIRE

    Uppireddi, Kishore; Westover, Tyler; Fisher, Timothy; Weiner, Brad; Morell, Gerardo

    2009-01-01

    In the ongoing quest for energy production by nonconventional methods, energy conversion by vacuum and solid-state thermionic emission devices is one of the potentially efficient pathways for converting thermal energy directly into electrical power. The realization of practical of thermionic energy conversion devices strongly depends on achieving low work function materials, which is thus far a limiting factor. In an attempt to develop a new low work function thermionic material, this work re...

  15. Prospects and Challenges of Thermal Energy Storage in Future Energy Systems

    OpenAIRE

    Holler, Stefan

    2013-01-01

    As a result of European energy and climate policy a growing share of renewable energy can be noted in European energy markets. Especially in the electricity market this leads to a higher volatility of the electricity price. In an open market this highly affects the share of cogeneration that is generally linked to local or district heating systems. The integration of thermal energy storage in district heating systems with cogeneration increases the flexibility of operation and thus maintains ...

  16. Biological limiting factors in Ocean Thermal Energy Conversion

    Energy Technology Data Exchange (ETDEWEB)

    Gray, R. H.

    1977-06-01

    Ocean thermal energy conversion (OTEC) is one of several solar energy options being considered by the U.S. Energy Research and Development Administration (ERDA). The OTEC concept utilizes the thermal difference between warm surface and cool, deep water in tropical oceans to operate a heat engine to produce either electricity or energy-intensive chemicals. Several OTEC system designs, both open and closed cycle, have been suggested. It is estimated that by the year 2020, 4 to 6% of the anticipated energy needs of the United States could be supplied by OTEC. However, primary biological films that reduce heat transfer at heat exchange surfaces are a major limiting factor to successful development of OTEC technology. Battelle, Pacific Northwest Laboratories (PNL) is managing an ERDA program aimed to define, prevent, and/or alleviate, potential biofouling problems associated with OTEC systems. Extensive research concerning open ocean biofouling and its control will be necessary. The OTEC concept, its history and potential advantages are discussed; various overall system designs are reviewed; and the biological limitations on OTEC development are dicussed. 33 references.

  17. Electric rate structures for thermal energy storage evaluation

    Energy Technology Data Exchange (ETDEWEB)

    Brown, D R; Garrett, S M; Sedgewick, J M

    1991-05-01

    Future electric rate structures are critical to thermal energy storage (TES) technologies that are specifically designed to take advantage of electric energy costs that vary depending on the magnitude, duration, and timing of power demand (e.g., cool storage). In fact, rate structure characteristics may affect the TES system design and operating approach as well as economic feasibility. The objective of this study, conducted by the Pacific Northwest Laboratory for the US Department of Energy, was to define reference electric utility rate structures to be used in technical assessments of TES technologies. Electric rate structures were characterized for residential, commercial and industrial sectors. A range of conditions for several alternative rate structures was identified for each sector to capture the variability of likely conditions. Individual rate structure characteristics include demand charges and energy charges applicable during different months of the year, days of the week, and hours of the day. 7 refs., 21 tabs.

  18. Preliminary investigations of the thermal energy grid concept

    Energy Technology Data Exchange (ETDEWEB)

    Olszewski, M.

    1977-10-01

    This study examines, in a preliminary manner, the feasibility of the thermal grid concept. This concept essentially envisions the supply of heat to a long-distance transmission line from a dual-purpose nuclear or coal-fired power plant. The transmission line delivers heat to a subregion distribution network which delivers it to the consumer. District chilled water supply is also considered, using heat from the grid to power steam-turbine-driven water chillers. Candidate technologies for generation, transmission, and distribution of thermal energy are identified and assessed. Potential applications, including both industrial use and residential space conditioning and hot water supply, are evaluated. Results indicate that high-temperature hot-water transmission lines are favored for longer distances, while steam lines may be acceptable for shorter distances. It is also evident that thermal grid heat is more economically competitive for new applications, as opposed to retrofit situations, in the residential-commercial sector. The two applications are about equally feasible in the industrial sector. The results further indicate that thermal grid heat is most competitive in areas of high-heat-load density and expensive fuel costs. It appears that the thermal grid service area should include the industrial sector as a base load. The multifamily residential-commercial sector space and water heating loads can be added to the service area to maximize utilization of the transmission line and maintain low transmission costs. Supply of chilled water to the multifamily residential-commercial sector can also be included for new applications to increase the transmission line use factor. The thermal grid concept appears to be economically and technically feasible, when compared to oil and electric systems in the multifamily residential-commercial sector and coal- or oil-fired systems in the industrial sector, and should be explored in greater detail.

  19. Numerical Modeling of a Shallow Borehole Thermal Energy Storage System

    Science.gov (United States)

    Catolico, N.; Ge, S.; Lu, N.; McCartney, J. S.

    2014-12-01

    Borehole thermal energy storage (BTES) combined with solar thermal energy harvesting is an economic technological system to garner and store energy as well as an environmentally-sustainable alternative for the heating of buildings. The first community-scale BTES system in North America was installed in 2007 in the Drake Landing Solar Community (DLSC), about 35 miles south of Calgary, Canada. The BTES system involves direct circulation of water heated from solar thermal panels in the summer into a storage tank, after which it is circulate within an array of 144 closed-loop geothermal heat exchangers having a depth of 35 m and a spacing of 2.5 m. In the winter the circulation direction is reversed to supply heat to houses. Data collection over a six year period indicates that this system can supply more than 90% of the winter heating energy needs for 52 houses in the community. One major challenge facing the BTES system technology is the relatively low annual efficiency, i.e., the ratio of energy input and output is in the range of 15% to 40% for the system in Drake Landing. To better understand the working principles of BTES and to improve BTES performance for future applications at larger scales, a three-dimensional transient coupled fluid and heat transfer model is established using TOUGH2. The time-dependent injection temperatures and circulation rate measured over the six years of monitoring are used as model input. The simulations are calibrated using soil temperature data measured at different locations over time. The time-dependent temperature distributions within the borehole region agree well with the measured temperatures for soil with an intrinsic permeability of 10e-19 m2, an apparent thermal conductivity of 2.03 W/m°C, and a volumetric heat capacity of 2.31 MJ/m-3°C. The calibrated model serves as the basis for a sensitivity analysis of soil and operational parameters on BTES system efficiency preformed with TOUGH2. Preliminary results suggest 1) BTES

  20. Thermal energy storage : a key technology for the food cold chain

    OpenAIRE

    Leducq, D.; Schalbart, P.; Trinquet, F.; Alvarez, G.; Verlinden, B.; Verboven, P.; Van Der Sluis, S.; Wessink, E.; Jay, F.; Pirani, M.; Indergård, E.

    2011-01-01

    In a context of greenhouse gas emissions, oil price rising and intermittent renewable energy sources, energy storage, and more specifically thermal energy storage is one of the best candidates to reduce and optimize the energy use of refrigerating systems. Moreover, the temperature stability and the autonomy of those systems in case of power failure, related to the use of thermal energy storage devices, is also an important factor of food quality and security enhancement. The thermal energy s...

  1. Economic Evaluation of a Solar Charged Thermal Energy Store for Space Heating

    OpenAIRE

    Melo, Manuel

    2013-01-01

    A thermal energy store corrects the misalignment of heating demand in the winter relative to solar thermal energy gathered in the summer. This thesis reviews the viability of a solar charged hot water tank thermal energy store for a school at latitude 56.25N, longitude -120.85W

  2. Thermal management in inertial fusion energy slab amplifiers

    International Nuclear Information System (INIS)

    As the technology associated with the development of solid-state drivers for inertial fusion energy (IFE) has evolved, increased emphasis has been placed on the development of an efficient approach for managing the waste heat generated in the laser media. This paper addresses the technical issues associated with the gas cooling of large aperture slabs, where the laser beam propagates through the cooling fluid. It is shown that the major consequence of proper thermal management is the introduction of simple wedge, or beam steering, into the system. Achieving proper thermal management requires careful consideration of the geometry, cooling fluid characteristics, cooling flow characteristics, as well as the thermal/mechanical/optical characteristics of the laser media. Particularly important are the effects of cooling rate variation and turbulent scattering on the system optical performance. Helium is shown to have an overwhelming advantage with respect to turbulent scattering losses. To mitigate cooling rate variations, the authors introduce the concept of flow conditioning. Finally, optical path length variations across the aperture are calculated. A comparison of two laser materials (S-FAP and YAG) shows the benefit of a nearly a-thermal material on optical variations in the system

  3. Thermal energy buffer storage for the small community solar thermal power experiment

    Science.gov (United States)

    Polzien, R. E.

    1981-03-01

    The application of a latent heat thermal energy buffer storage (TEBS) subsystem to the small community solar thermal power experiment (SCSE) is discussed. The SCSE consists of multiple point focusing distributed receiver (PFDR) power modules equipped with an organic Rankine cycle power conversion unit mounted at the focus of each paraboloidal concentrator. The objective of the TEBS is to minimize plant shutdowns during intermittent cloud coverages, thereby improving life expectancy of the major subsystems with attendant reduction in capital investment and maintenance costs. An SCSE plant performance model modified for operation with a TEBS system is used with time varying insolation to show that 70 to 80 percent of the potential engine shutdowns due to insolation dropout may be averted with the TEBS system. Results of preliminary design analyses of various TEBS concepts are discussed.

  4. Review of pyroelectric thermal energy harvesting and new MEMs based resonant energy conversion techniques

    Energy Technology Data Exchange (ETDEWEB)

    Hunter, Scott Robert [ORNL; Lavrik, Nickolay V [ORNL; Mostafa, Salwa [ORNL; Rajic, Slobodan [ORNL; Datskos, Panos G [ORNL

    2012-01-01

    Harvesting electrical energy from thermal energy sources using pyroelectric conversion techniques has been under investigation for over 50 years, but it has not received the attention that thermoelectric energy harvesting techniques have during this time period. This lack of interest stems from early studies which found that the energy conversion efficiencies achievable using pyroelectric materials were several times less than those potentially achievable with thermoelectrics. More recent modeling and experimental studies have shown that pyroelectric techniques can be cost competitive with thermoelectrics and, using new temperature cycling techniques, has the potential to be several times as efficient as thermoelectrics under comparable operating conditions. This paper will review the recent history in this field and describe the techniques that are being developed to increase the opportunities for pyroelectric energy harvesting. The development of a new thermal energy harvester concept, based on temperature cycled pyroelectric thermal-to-electrical energy conversion, are also outlined. The approach uses a resonantly driven, pyroelectric capacitive bimorph cantilever structure that can be used to rapidly cycle the temperature in the energy harvester. The device has been modeled using a finite element multi-physics based method, where the effect of the structure material properties and system parameters on the frequency and magnitude of temperature cycling, and the efficiency of energy recycling using the proposed structure, have been modeled. Results show that thermal contact conductance and heat source temperature differences play key roles in dominating the cantilever resonant frequency and efficiency of the energy conversion technique. This paper outlines the modeling, fabrication and testing of cantilever and pyroelectric structures and single element devices that demonstrate the potential of this technology for the development of high efficiency thermal

  5. Review of pyroelectric thermal energy harvesting and new MEMs-based resonant energy conversion techniques

    Science.gov (United States)

    Hunter, Scott R.; Lavrik, Nickolay V.; Mostafa, Salwa; Rajic, Slo; Datskos, Panos G.

    2012-06-01

    Harvesting electrical energy from thermal energy sources using pyroelectric conversion techniques has been under investigation for over 50 years, but it has not received the attention that thermoelectric energy harvesting techniques have during this time period. This lack of interest stems from early studies which found that the energy conversion efficiencies achievable using pyroelectric materials were several times less than those potentially achievable with thermoelectrics. More recent modeling and experimental studies have shown that pyroelectric techniques can be cost competitive with thermoelectrics and, using new temperature cycling techniques, has the potential to be several times as efficient as thermoelectrics under comparable operating conditions. This paper will review the recent history in this field and describe the techniques that are being developed to increase the opportunities for pyroelectric energy harvesting. The development of a new thermal energy harvester concept, based on temperature cycled pyroelectric thermal-to-electrical energy conversion, are also outlined. The approach uses a resonantly driven, pyroelectric capacitive bimorph cantilever structure that can be used to rapidly cycle the temperature in the energy harvester. The device has been modeled using a finite element multi-physics based method, where the effect of the structure material properties and system parameters on the frequency and magnitude of temperature cycling, and the efficiency of energy recycling using the proposed structure, have been modeled. Results show that thermal contact conductance and heat source temperature differences play key roles in dominating the cantilever resonant frequency and efficiency of the energy conversion technique. This paper outlines the modeling, fabrication and testing of cantilever and pyroelectric structures and single element devices that demonstrate the potential of this technology for the development of high efficiency thermal

  6. Sodium-based hydrides for thermal energy applications

    Science.gov (United States)

    Sheppard, D. A.; Humphries, T. D.; Buckley, C. E.

    2016-04-01

    Concentrating solar-thermal power (CSP) with thermal energy storage (TES) represents an attractive alternative to conventional fossil fuels for base-load power generation. Sodium alanate (NaAlH4) is a well-known sodium-based complex metal hydride but, more recently, high-temperature sodium-based complex metal hydrides have been considered for TES. This review considers the current state of the art for NaH, NaMgH3- x F x , Na-based transition metal hydrides, NaBH4 and Na3AlH6 for TES and heat pumping applications. These metal hydrides have a number of advantages over other classes of heat storage materials such as high thermal energy storage capacity, low volume, relatively low cost and a wide range of operating temperatures (100 °C to more than 650 °C). Potential safety issues associated with the use of high-temperature sodium-based hydrides are also addressed.

  7. Equilibrium Statistical-Thermal Models in High-Energy Physics

    CERN Document Server

    Tawfik, Abdel Nasser

    2014-01-01

    We review some recent highlights from the applications of statistical-thermal models to different experimental measurements and lattice QCD thermodynamics, that have been made during the last decade. We start with a short review of the historical milestones on the path of constructing statistical-thermal models for heavy-ion physics. We discovered that Heinz Koppe formulated in 1948 an almost complete recipe for the statistical-thermal models. In 1950, Enrico Fermi generalized this statistical approach, in which he started with a general cross-section formula and inserted into it simplifying assumptions about the matrix element of the interaction process that likely reflects many features of the high-energy reactions dominated by density in the phase space of final states. In 1964, Hagedorn systematically analysed the high-energy phenomena using all tools of statistical physics and introduced the concept of limiting temperature based on the statistical bootstrap model. It turns to be quite often that many-par...

  8. Advanced Reactors Thermal Energy Transport for Process Industries

    Energy Technology Data Exchange (ETDEWEB)

    P. Sabharwall; S.J. Yoon; M.G. McKellar; C. Stoots; George Griffith

    2014-07-01

    The operation temperature of advanced nuclear reactors is generally higher than commercial light water reactors and thermal energy from advanced nuclear reactor can be used for various purposes such as liquid fuel production, district heating, desalination, hydrogen production, and other process heat applications, etc. Some of the major technology challenges that must be overcome before the advanced reactors could be licensed on the reactor side are qualification of next generation of nuclear fuel, materials that can withstand higher temperature, improvement in power cycle thermal efficiency by going to combined cycles, SCO2 cycles, successful demonstration of advanced compact heat exchangers in the prototypical conditions, and from the process side application the challenge is to transport the thermal energy from the reactor to the process plant with maximum efficiency (i.e., with minimum temperature drop). The main focus of this study is on doing a parametric study of efficient heat transport system, with different coolants (mainly, water, He, and molten salts) to determine maximum possible distance that can be achieved.

  9. Thermal energy storage for sustainable energy consumption : fundamentals, case studies and design

    CERN Document Server

    Paksoy, Halime Ö

    2007-01-01

    We all share a small planet. Our growing thirst for energy already threatens the future of our earth. Fossil fuels - energy resources of today - are not evenly distributed on the earth. 10 per cent of the world's population exploits 90 per cent of its resources. Today's energy systems rely heavily on fossil fuel resources which are diminishing ever faster. The world must prepare for a future without fossil fuels. Thermal energy storage provides us with a flexible heating and/or cooling tool to combat climate change through conserving energy and increasing energy while utilizing natural renewab

  10. New kinds of energy-storing building composite PCMs for thermal energy storage

    International Nuclear Information System (INIS)

    Graphical abstract: In this work, 10 new kinds of BCPCMs were prepared by blending of liquid xylitol pentalaurate (XPL) and xylitol pentamyristate (XPM) esters into gypsum, cement, diatomite, perlite and vermiculite. DSC results showed that the melting temperatures and energy storage capacities of the prepared BCPCMs are in range of about 40–55 °C and 31–126 J/g, respectively. TG investigations and thermal cycling test showed that the BCPCMs had good thermal endurance and thermal reliability. It can be also concluded that among the prepared 10 kinds materials, especially the BCPCMs including perlite, vermiculite, diatomite were found to better candidates for thermal energy storage applications in buildings due to the fact that they have relatively high heat storage ability. Highlights: ► New kinds BCPCMs were prepared by blending of liquid XPL and XPM esters with some building materials. ► The BCPCMs had suitable melting temperatures and energy storage capacities. ► Especially, the BCPCMs including perlite, vermiculite, diatomite were found to better candidates for thermal energy storage. - Abstract: Energy storing-composite phase change materials (PCMs) are significant means of thermal energy storage in buildings. Although several building composite PCMs (BCPCMs) have been developed in recent years, the additional investigations are still required to enrich the diversity of BCPCMs for solar heating and energy conservation applications in buildings. For this purpose, the present work is focused the preparation, characterization and determination of 10 new kinds of BCPCMs. The BCPCMs were prepared by blending of liquid xylitol pentalaurate (XPL) and xylitol pentamyristate (XPM) esters with gypsum, cement, diatomite, perlite and vermiculite as supporting matrices. The scanning electron microscopy (SEM) and Fourier Transform Infrared (FT-IR) analysis showed that the ester compounds were adsorbed uniformly into the building materials due to capillary forces

  11. Thermal energy storage. [by means of chemical reactions

    Science.gov (United States)

    Grodzka, P. G.

    1975-01-01

    The principles involved in thermal energy storage by sensible heat, chemical potential energy, and latent heat of fusion are examined for the purpose of evolving selection criteria for material candidates in the low ( 0 C) and high ( 100 C) temperature ranges. The examination identifies some unresolved theoretical considerations and permits a preliminary formulation of an energy storage theory. A number of candidates in the low and high temperature ranges are presented along with a rating of candidates or potential candidates. A few interesting candidates in the 0 to 100 C region are also included. It is concluded that storage by means of reactions whose reversibility can be controlled either by product removal or by catalytic means appear to offer appreciable advantages over storage with reactions whose reversability cannot be controlled. Among such advantages are listed higher heat storage capacities and more favorable options regarding temperatures of collection, storage, and delivery. Among the disadvantages are lower storage efficiencies.

  12. Energy Conversion of an Environmental Thermal (T ~ 300K) Energy into Electrical Energy by Nanoscale Field Emission Systems

    OpenAIRE

    Ptitsin V.E.

    2014-01-01

    Physical and numerical modeling of the field emission energy conversion (FEEC) nanoscale systems is carried out. It is shown, that FEEC systems with a cathodes based on an array of carbon nanotubes or quantum dots (at a temperature of the cathode T ~ 300 K) are able to realize effective conversion of an environmental thermal energy into electrical energy.

  13. Conceptual design of thermal energy storage systems for near-term electric utility applications

    Science.gov (United States)

    Hall, E. W.

    1980-01-01

    Promising thermal energy storage systems for midterm applications in conventional electric utilities for peaking power generation are evaluated. Conceptual designs of selected thermal energy storage systems integrated with conventional utilities are considered including characteristics of alternate systems for peaking power generation, viz gas turbines and coal fired cycling plants. Competitive benefit analysis of thermal energy storage systems with alternate systems for peaking power generation and recommendations for development and field test of thermal energy storage with a conventional utility are included. Results indicate that thermal energy storage is only marginally competitive with coal fired cycling power plants and gas turbines for peaking power generation.

  14. Finite-difference grid for a doublet well in an anisotropic aquifer

    Science.gov (United States)

    Miller, R.T.; Voss, C.I.

    1986-01-01

    The U.S. Geological Survey is modeling hydraulic flow and thermal-energy transport at a two-well injection/ withdrawal system in St. Paul, Minnesota. The design of the finite-difference model grid for the doublet-well system is complicated because the aquifer is anisotropic and the principal axes of transmissivity are not aligned with the axis between the two wells.

  15. Thermal Energy Corporation Combined Heat and Power Project

    Energy Technology Data Exchange (ETDEWEB)

    Turner, E. Bruce [Thermal Energy Corporation, Houston, TX (United States); Brown, Tim [Thermal Energy Corporation, Houston, TX (United States); Mardiat, Ed [Burns and McDonnell Engineering Company, Inc., Kansas City, MI (United States)

    2011-12-31

    To meet the planned heating and cooling load growth at the Texas Medical Center (TMC), Thermal Energy Corporation (TECO) implemented Phase 1 of a Master Plan to install an additional 32,000 tons of chilled water capacity, a 75,000 ton-hour (8.8 million gallon) Thermal Energy Storage (TES) tank, and a 48 MW Combined Heat and Power (CHP) system. The Department of Energy selected TMC for a $10 million grant award as part of the Financial Assistance Funding Opportunity Announcement, U.S. Department of Energy National Energy Technology, Recovery Act: Deployment of Combined Heat and Power (CHP) Systems, District Energy Systems, Waste Energy Recovery Systems, and Efficiency Industrial Equipment Funding Opportunity Number: DE-FOA-0000044 to support the installation of a new 48 MW CHP system at the TMC located just outside downtown Houston. As the largest medical center in the world, TMC is home to many of the nation's best hospitals, physicians, researchers, educational institutions, and health care providers. TMC provides care to approximately six million patients each year, and medical instruction to over 71,000 students. A medical center the size of TMC has enormous electricity and thermal energy demands to help it carry out its mission. Reliable, high-quality steam and chilled water are of utmost importance to the operations of its many facilities. For example, advanced medical equipment, laboratories, laundry facilities, space heating and cooling all rely on the generation of heat and power. As result of this project TECO provides this mission critical heating and cooling to TMC utilizing a system that is both energy-efficient and reliable since it provides the capability to run on power independent of the already strained regional electric grid. This allows the medical center to focus on its primary mission providing top quality medical care and instruction without worrying about excessive energy costs or the loss of heating and cooling due to the risk of power

  16. Solar thermal energy foresees future in great hopes

    International Nuclear Information System (INIS)

    Multiple big projects of solar thermal and photovoltaic power plants have recently put solar energy again on the front of the energy scene. These projects stimulate the researches on the key technologies of this industry: the heat transfer fluids and the light focussing optics. 679 MW of solar thermal energy were installed in 2009, from which 63% in the USA and 32% in Spain. 88% of the sites use parabolic mirrors to concentrate the solar radiation. 2000 MW of additional capacity are currently under construction. However several obstacles have to be overcome: a direct insolation without dusts, clouds or smokes (desertic areas), a plant size limited by the size of the local power grid, huge quantities of water requested by the thermodynamic cycle of the conversion process, and technologies that remain costly because still under development. Optical systems are under development for solar cells as well. They allow to reduce the size (and the cost) of the solar panels with keeping the same efficiency. (J.S.)

  17. ANALYSIS OF THERMAL-CHEMICAL CHARACTERISTICS OF BIOMASS ENERGY PELLETS

    Directory of Open Access Journals (Sweden)

    Zorica Gluvakov

    2014-09-01

    Full Text Available In modern life conditions, when emphasis is on environmental protection and sustainable development, fuels produced from biomass are increasingly gaining in importance, and it is necessary to consider the quality of end products obtained from biomass. Based on the existing European standards, collected literature and existing laboratory methods, this paper presents results of testing individual thermal - chemical properties of biomass energy pellets after extrusion and cooling the compressed material. Analysing samples based on standard methods, data were obtained on the basis of which individual thermal-chemical properties of pellets were estimated. Comparing the obtained results with the standards and literature sources, it can be said that moisture content, ash content and calorific values are the most important parameters for quality analysis which decide on applicability and use-value of biomass energy pellets, as biofuel. This paper also shows the impact of biofuels on the quality of environmental protection. The conclusion provides a clear statement of quality of biomass energy pellets.

  18. Significant thermal energy reduction in lactic acid production process

    International Nuclear Information System (INIS)

    Lactic acid is widely used as a raw material for the production of biodegradable polymers and in food, chemical and pharmaceutical industries. The global market for lactic acid is expected to reach 259 thousand metric tons by the year 2012. For batch production of lactic acid, the traditional process includes the following steps: (i) esterification of impure lactic acid with methanol in a batch reactor to obtain methyl lactate (ester), (ii) separation of the ester in a batch distillation, (iii) hydrolysis of the ester with water in a batch reactor to produce lactic acid and (iv) separation of lactic acid (in high purity) in a batch distillation. Batch reactive distillation combines the benefit of both batch reactor and batch distillation and enhances conversion and productivity (Taylor and Krishna, 2000 ; Mujtaba and Macchietto, 1997 ). Therefore, the first and the last two steps of the lactic acid production process can be combined together in batch reactive distillation () processes. However, distillation (batch or continuous) is an energy intensive process and consumes large amount of thermal energy (via steam). This paper highlights how significant (over 50%) reduction in thermal energy consumption can be achieved for lactic acid production process by carefully controlling the reflux ratio but without compromising the product specification. In this paper, only the simultaneous hydrolysis of methyl lactate ester and the separation of lactic acid using batch reactive distillation is considered.

  19. Feasibility study of thermal energy harvesting using lead free pyroelectrics

    Science.gov (United States)

    Karim, Hasanul; Sarker, Md Rashedul H.; Shahriar, Shaimum; Arif Ishtiaque Shuvo, Mohammad; Delfin, Diego; Hodges, Deidra; (Bill Tseng, Tzu-Liang; Roberson, David; Love, Norman; Lin, Yirong

    2016-05-01

    Energy harvesting has significant potential for applications in energizing wireless sensors and charging energy storage devices. To date, one of the most widely investigated materials for mechanical and thermal energy harvesting is lead zirconate titanate (PZT). However, lead has detrimental effects on the environment and on health. Hence, alternative materials are required for this purpose. In this paper, a lead free material, lithium niobate (LNB) is investigated as a potential material for pyroelectric energy harvesting. Although its theoretical pyroelectric properties are lower compared to PZT, it has better properties than other lead free alternatives such as ZnO. In addition, LNB has a high Curie temperature of about 1142 °C, which makes it applicable for high temperature energy harvesting, where other pyroelectric ceramics are not suitable. Herein, an energy harvesting and storage system composed of a single crystal LNB and a porous carbon-based super-capacitor was investigated. It is found that with controlled heating and cooling, a single wafer of LNB (75 mm diameter and 0.5 mm thickness) could generate 437.72 nW cm–3 of power and it could be used to charge a super-capacitor with a charging rate of 2.63 mV (h cm3)–1.

  20. Thermal energy harvesters with piezoelectric or electrostatic transducer

    Science.gov (United States)

    Prokaryn, Piotr; Domański, Krzysztof; Marchewka, Michał; Tomaszewski, Daniel; Grabiec, Piotr; Puscasu, Onoriu; Monfray, Stéphane; Skotnicki, Thomas

    2014-08-01

    This paper describes the idea of the energy harvester which converts thermal gradient present in environment into electricity. Two kinds of such devices are proposed and their prototypes are shown and discussed. The main parts of harvesters are bimetallic spring, piezoelectric transducer or electrostatic transducer with electret. The applied piezomembrane was commercial available product but electrets was made by authors. In the paper a fabrication procedure of electrets formed by the corona discharge process is described. Devices were compared in terms of generated power, charging current, and the voltage across a storage capacitor.

  1. Promotion of solar thermal energy - guide and comparison of experience

    Energy Technology Data Exchange (ETDEWEB)

    Ballot, E. [ALTER Alsace (France)

    2004-01-01

    One of the objectives of the guide is to analyse the methods of the various partners of the project (Germany, Cyprus, Town of Barcelona and France) and to make a list with the most important ones, which could eventually be reproduced and adapted in other regions. Also, try to find out the problems that the various partners encounter (lack of information, technical and financial tools...), look for the best ways for developing the solar thermal energy and try to find out some answers from the stake holders of this domain and from our partners. (author)

  2. Bibliography of the seasonal thermal energy storage library

    Energy Technology Data Exchange (ETDEWEB)

    Prater, L.S.; Casper, G.; Kawin, R.A.

    1981-08-01

    The Main Listing is arranged alphabetically by the last name of the first author. Each citation includes the author's name, title, publisher, publication date, and where applicable, the National Technical Information Service (NTIS) number or other document number. The number preceding each citation is the identification number for that document in the Seasonal Thermal Energy Storage (STES) Library. Occasionally, one or two alphabetic characters are added to the identification number. These alphabetic characters indicate that the document is contained in a collection of papers, such as the proceedings of a conference. An Author Index and an Identification Number Index are included. (WHK)

  3. Heat transfer research for ocean thermal energy conversion

    Energy Technology Data Exchange (ETDEWEB)

    Kreith, F.; Bharathan, D.

    1988-02-01

    In this lecture an overview of the heat and mass-transfer phenomena of importance in ocean thermal energy conversion (OTEC) is presented with particular emphasis on open-cycle OTEC systems. Also included is a short historical review of OTEC developments in the past century and a comparison of open and closed-cycle thermodynamics. Finally, results of system analyses, showing the effect of plant size on cost and the near-term potential of using OTEC for combined power production and desalination systems, are briefly discussed.

  4. Heat transfer research for ocean thermal energy conversion

    Science.gov (United States)

    Kreith, F.; Bharathan, D.

    1987-03-01

    In this lecture an overview of the heat- and mass-transfer phenomena of importance in ocean thermal energy conversion (OTEC) is presented with particular emphasis on open-cycle OTEC systems. Also included is a short historical review of OTEC developments in the past century and a comparison of open- and closed-cycle thermodynamics. Finally, results of system analyses, showing the effect of plant size on cost and the near-term potential of using OTEC for combined power production and desalination systems are briefly discussed.

  5. Thermal characteristic reliability of fatty acid binary mixtures as phase change materials (PCMs) for thermal energy storage applications

    International Nuclear Information System (INIS)

    The thermal characteristic reliability of two binary mixtures of fatty acid, myristic acid/palmitic acid/sodium myristate (MA/PA/SM) and myristic acid/palmitic acid/sodium palmitate (MA/PA/SP), were investigated using a thermal cycling test setup for 0, 1000, 2000, 3000, and 3600 heating/cooling cycles. The changes in thermal properties and chemical bonding of both eutectic PCMs were measured using Differential Scanning Calorimetric (DSC) and Fourier Transform Infrared Spectroscopy (FT-IR) analyzer, respectively. MA/PA/SM and MA/PA/SP eutectic mixtures shows only minor changes in phase transition temperature (Tm, Ts) and in latent heat of fusion (ΔHf). Moreover, the chemical bonding structures of these eutectic PCMs show no degradation and the thermal performance of those PCMs shows a good stability after 3600 thermal cycles. Therefore, it is found that the thermal characteristic stability of prepared MA/PA/SM and MA/PA/SP eutectic mixtures were acceptable for long term performance and economic feasibilities used as a phase change material (PCM) for thermal energy storage (TES) application. - Highlights: • The MA/PA/SM and MA/PA/SP were used as eutectic phase change materials (PCM). • Thermal reliability of eutectic PCMs evaluated using a thermal cycling test. • MA/PA/SP has a great thermal characteristic than MA/PA/SM after 3600 thermal cycles. • The eutectic PCMs did not show change of appearance after 3600 thermal cycles

  6. Technical and economic feasibility of thermal energy storage. Thermal energy storage application to the brick/ceramic industry. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Glenn, D.R.

    1976-10-01

    An initial project to study the technical and economic feasibility of thermal energy storage (TES) in the three major consumer markets, namely, the residential, commercial and industrial sectors is described. A major objective of the study was to identify viable TES applications from which a more concise study could be launched, leading to a conceptual design and in-depth validation of the TES energy impacts. This report documents one such program. The brick/ceramic industries commonly use periodic kilns which by their operating cycle require time-variant energy supply and consequently variable heat rejection. This application was one of the numerous TES opportunities that emerged from the first study, now available from the ERDA Technical Information Center, Oak Ridge, Tennessee, identified as Report No. COO-2558-1.

  7. Numerical simulation of high-temperature phase transition thermal energy storage container for solar thermal power generation applications

    OpenAIRE

    Haiting CUI; Sun, Kunkun; Ning LI

    2015-01-01

    The heat storage process of the high temperature thermal energy storage container using single-stage PCM for solar thermal power generation is numerically simulated. The change curves of the PCM's temperature and liquid rate over time during the single-stage thermal stage melting process and its cloud distributions of the liquid rate at different time have been obtained. Through the analysis of the curves and cloud figures, in the premise of ensuring the heat accumulation amount, three kinds ...

  8. A system for measuring thermal activation energy levels in silicon by thermally stimulated capacitance

    Science.gov (United States)

    Cockrum, R. H.

    1982-01-01

    One method being used to determine energy level(s) and electrical activity of impurities in silicon is described. The method is called capacitance transient spectroscopy (CTS). It can be classified into three basic categories: the thermally stimulated capacitance method, the voltage-stimulated capacitance method, and the light-stimulated capacitance method; the first two categories are discussed. From the total change in capacitance and the time constant of the capacitance response, emission rates, energy levels, and trap concentrations can be determined. A major advantage of using CTS is its ability to detect the presence of electrically active impurities that are invisible to other techniques, such as Zeeman effect atomic absorption, and the ability to detect more than one electrically active impurity in a sample. Examples of detection of majority and minority carrier traps from gold donor and acceptor centers in silicon using the capacitance transient spectrometer are given to illustrate the method and its sensitivity.

  9. Molten salt thermal energy storage systems. Project 8981, final report

    Energy Technology Data Exchange (ETDEWEB)

    Maru, H.C.; Dullea, J.F.; Kardas, A.; Paul, L.

    1978-03-01

    The feasibility of storing thermal energy at temperatures of 450/sup 0/ to 535/sup 0/C (850/sup 0/ to 1000/sup 0/F) in the form of latent heat of fusion has been examined for over 30 inorganic salts and salt mixtures. Alkali carbonate mixtures are attractive as phase-change storage materials in this temperature range because of their relatively high storage capacity and thermal conductivity, moderate cost, low volumetric expansion upon melting, low corrosivity, and good chemical stability. An equimolar mixture of Li/sub 2/CO/sub 3/ and K/sub 2/CO/sub 3/, which melts at 505/sup 0/C with a latent heat of 148 Btu/lb, was chosen for experimental study. The cyclic charge/discharge behavior of laboratory- and engineering-scale systems was determined and compared with predictions based on a mathematical heat-transfer model that was developed during this program. The thermal performance of one engineering-scale unit remained very stable during 1400 hours of cyclic operation. Several means of improving heat conduction through the solid salt were explored. Areas requiring further investigation have been identified.

  10. High efficiency thermal energy storage system for utility applications

    International Nuclear Information System (INIS)

    A concept of coupling a high efficiency base loaded coal or nuclear power plant with a thermal energy storage scheme for efficient and low-cost intermediate and peaking power is presented. A portion of the power plant's thermal output is used directly to generate superheated steam for continuous operation of a conventional turbine-generator to product base-load power. The remaining thermal output is used on a continuous basis to heat a conventional heat transfer salt (such as the eutectic composition of KaNO3/NaNO3/NaNO2), which is stored in a high-temperature reservoir [5380C (10000F)]. During peak demand periods, the salt is circulated from the high-temperature reservoir to a low-temperature reservoir through steam generators in order to provide peaking power from a conventional steam cycle plant. The period of operation can vary, but may typically be the equivalent of about 4 to 8 full-power hours each day. The system can be tailored to meet the utilities' load demand by varying the base-load level and the period of operation of the peak-load system

  11. Effect of carbon nanospheres on shape stabilization and thermal behavior of phase change materials for thermal energy storage

    International Nuclear Information System (INIS)

    Highlights: • Introducing novel form-stable PCM of stearic acid (SA)/carbon nanospheres (CNSs). • The highest stabilized SA content is 83 wt% in the SA/CNS composites. • Increasing thermal conductivity of composite phase change material with high amount of latent heat. - Abstract: Stearic acid (SA) is one of the main phase change materials (PCMs) for medium temperature thermal energy storage systems. In order to stabilize the shape and enhance the thermal conductivity of SA, the effects of adding carbon nanospheres (CNSs) as a carbon nanofiller were examined experimentally. The maximum mass fraction of SA retained in CNSs was found as 80 wt% without the leakage of SA in a melted state, even when it was heated over the melting point of SA. The dropping point test shows that there was clearly no liquid leakage through the phase change process at the operating temperature range of the composite PCMs. The thermal stability and thermal properties of composite PCMs were investigated with a thermogravimetric analyzer (TGA) and differential scanning calorimeter (DSC), respectively. The thermal conductivity of the SA/CNS composite was determined by the laser flash method. The thermal conductivity at 35 °C increased about 105% for the highest loading of CNS (50 wt%). The thermal cycling test proved that form-stable composite PCMs had good thermal reliability and chemical durability after 1000 cycles of melting and freezing, which is advantageous for latent heat thermal energy storage (LHTES)

  12. Thermal effects on microbial composition and microbiologically induced corrosion and mineral precipitation affecting operation of a geothermal plant in a deep saline aquifer.

    Science.gov (United States)

    Lerm, Stephanie; Westphal, Anke; Miethling-Graff, Rona; Alawi, Mashal; Seibt, Andrea; Wolfgramm, Markus; Würdemann, Hilke

    2013-03-01

    The microbial diversity of a deep saline aquifer used for geothermal heat storage in the North German Basin was investigated. Genetic fingerprinting analyses revealed distinct microbial communities in fluids produced from the cold and warm side of the aquifer. Direct cell counting and quantification of 16S rRNA genes and dissimilatory sulfite reductase (dsrA) genes by real-time PCR proved different population sizes in fluids, showing higher abundance of bacteria and sulfate reducing bacteria (SRB) in cold fluids compared with warm fluids. The operation-dependent temperature increase at the warm well probably enhanced organic matter availability, favoring the growth of fermentative bacteria and SRB in the topside facility after the reduction of fluid temperature. In the cold well, SRB predominated and probably accounted for corrosion damage to the submersible well pump and iron sulfide precipitates in the near wellbore area and topside facility filters. This corresponded to lower sulfate content in fluids produced from the cold well as well as higher content of hydrogen gas that was probably released from corrosion, and maybe favored growth of hydrogenotrophic SRB. This study reflects the high influence of microbial populations for geothermal plant operation, because microbiologically induced precipitative and corrosive processes adversely affect plant reliability. PMID:23358731

  13. A novel application of concentrated solar thermal energy in foundries.

    Science.gov (United States)

    Selvaraj, J; Harikesavan, V; Eshwanth, A

    2016-05-01

    Scrap preheating in foundries is a technology that saves melting energy, leading to economic and environmental benefits. The proposed method in this paper utilizes solar thermal energy for preheating scrap, effected through a parabolic trough concentrator that focuses sunlight onto a receiver which carries the metallic scrap. Scraps of various thicknesses were placed on the receiver to study the heat absorption by them. Experimental results revealed the pattern with which heat is gained by the scrap, the efficiency of the process and how it is affected as the scrap gains heat. The inferences from them gave practical guidelines on handling scraps for best possible energy savings. Based on the experiments conducted, preheat of up to 160 °C and a maximum efficiency of 70 % and a minimum efficiency of 40 % could be achieved across the time elapsed and heat gained by the scrap. Calculations show that this technology has the potential to save around 8 % of the energy consumption in foundries. Cumulative benefits are very encouraging: 180.45 million kWh of energy savings and 203,905 t of carbon emissions cut per year across the globe. This research reveals immense scope for this technology to be adopted by foundries throughout the world. PMID:26208658

  14. Heat tracer test in an alluvial aquifer: Field experiment and inverse modelling

    Science.gov (United States)

    Klepikova, Maria; Wildemeersch, Samuel; Hermans, Thomas; Jamin, Pierre; Orban, Philippe; Nguyen, Frédéric; Brouyère, Serge; Dassargues, Alain

    2016-09-01

    Using heat as an active tracer for aquifer characterization is a topic of increasing interest. In this study, we investigate the potential of using heat tracer tests for characterization of a shallow alluvial aquifer. A thermal tracer test was conducted in the alluvial aquifer of the Meuse River, Belgium. The tracing experiment consisted in simultaneously injecting heated water and a dye tracer in an injection well and monitoring the evolution of groundwater temperature and tracer concentration in the pumping well and in measurement intervals. To get insights in the 3D characteristics of the heat transport mechanisms, temperature data from a large number of observation wells closely spaced along three transects were used. Temperature breakthrough curves in observation wells are contrasted with what would be expected in an ideal layered aquifer. They reveal strongly unequal lateral and vertical components of the transport mechanisms. The observed complex behavior of the heat plume is explained by the groundwater flow gradient on the site and heterogeneities in the hydraulic conductivity field. Moreover, due to high injection temperatures during the field experiment a temperature-induced fluid density effect on heat transport occurred. By using a flow and heat transport numerical model with variable density coupled with a pilot point approach for inversion of the hydraulic conductivity field, the main preferential flow paths were delineated. The successful application of a field heat tracer test at this site suggests that heat tracer tests is a promising approach to image hydraulic conductivity field. This methodology could be applied in aquifer thermal energy storage (ATES) projects for assessing future efficiency that is strongly linked to the hydraulic conductivity variability in the considered aquifer.

  15. Improvement of Pyroelectric Cells for Thermal Energy Harvesting

    Directory of Open Access Journals (Sweden)

    Jing-Chih Ciou

    2012-01-01

    Full Text Available This study proposes trenching piezoelectric (PZT material in a thicker PZT pyroelectric cell to improve the temperature variation rate to enhance the efficiency of thermal energy-harvesting conversion by pyroelectricity. A thicker pyroelectric cell is beneficial in generating electricity pyroelectrically, but it hinders rapid temperature variations. Therefore, the PZT sheet was fabricated to produce deeper trenches to cause lateral temperature gradients induced by the trenched electrode, enhancing the temperature variation rate under homogeneous heat irradiation. When the trenched electrode type with an electrode width of 200 μm and a cutting depth of 150 μm was used to fabricate a PZT pyroelectric cell with a 200 μm thick PZT sheet, the temperature variation rate was improved by about 55%. Therefore, the trenched electrode design did indeed enhance the temperature variation rate and the efficiency of pyroelectric energy converters.

  16. Improvement of pyroelectric cells for thermal energy harvesting.

    Science.gov (United States)

    Hsiao, Chun-Ching; Siao, An-Shen; Ciou, Jing-Chih

    2012-01-01

    This study proposes trenching piezoelectric (PZT) material in a thicker PZT pyroelectric cell to improve the temperature variation rate to enhance the efficiency of thermal energy-harvesting conversion by pyroelectricity. A thicker pyroelectric cell is beneficial in generating electricity pyroelectrically, but it hinders rapid temperature variations. Therefore, the PZT sheet was fabricated to produce deeper trenches to cause lateral temperature gradients induced by the trenched electrode, enhancing the temperature variation rate under homogeneous heat irradiation. When the trenched electrode type with an electrode width of 200 μm and a cutting depth of 150 μm was used to fabricate a PZT pyroelectric cell with a 200 μm thick PZT sheet, the temperature variation rate was improved by about 55%. Therefore, the trenched electrode design did indeed enhance the temperature variation rate and the efficiency of pyroelectric energy converters. PMID:22368484

  17. A thermal approach to waveform–independent energy determination

    International Nuclear Information System (INIS)

    In this paper, a new device for power and rms value measurement is presented. Unlike the commercially available measurement equipment, this device is not limited to special waveforms. As a reaction to the increasing use of energy harvesters, which gather energy from the ambience to power low-power electronics, it is necessary to develop new measurement equipment that is not limited to sinusoidal signals (harvesters generally deliver nonsinusoidal signals). Therefore, a new device is presented based on an isothermal operating mode of a planar multijunction thermal converter (PMJTC). Unlike previous PMJTCs, this one is equipped with an additional gold heater and is operated by a regulating circuit, which is electrically isolated from the input. The output signal of the regulator is recorded and analyzed to determine the power and rms value of the input signal. (paper)

  18. Thermal energy storage for the Stirling engine powered automobile

    Science.gov (United States)

    Morgan, D. T. (Editor)

    1979-01-01

    A thermal energy storage (TES) system developed for use with the Stirling engine as an automotive power system has gravimetric and volumetric storage densities which are competitive with electric battery storage systems, meets all operational requirements for a practical vehicle, and can be packaged in compact sized automobiles with minimum impact on passenger and freight volume. The TES/Stirling system is the only storage approach for direct use of combustion heat from fuel sources not suitable for direct transport and use on the vehicle. The particular concept described is also useful for a dual mode TES/liquid fuel system in which the TES (recharged from an external energy source) is used for short duration trips (approximately 10 miles or less) and liquid fuel carried on board the vehicle used for long duration trips. The dual mode approach offers the potential of 50 percent savings in the consumption of premium liquid fuels for automotive propulsion in the United States.

  19. Utilizing Ocean Thermal Energy in a Submarine Robot

    Science.gov (United States)

    Jones, Jack; Chao, Yi

    2009-01-01

    A proposed system would exploit the ocean thermal gradient for recharging the batteries in a battery-powered unmanned underwater vehicle [UUV (essentially, a small exploratory submarine robot)] of a type that has been deployed in large numbers in research pertaining to global warming. A UUV of this type travels between the ocean surface and depths, measuring temperature and salinity. The proposed system is related to, but not the same as, previously reported ocean thermal energy conversion (OTEC) systems that exploit the ocean thermal gradient but consist of stationary apparatuses that span large depth ranges. The system would include a turbine driven by working fluid subjected to a thermodynamic cycle. CO2 has been provisionally chosen as the working fluid because it has the requisite physical properties for use in the range of temperatures expected to be encountered in operation, is not flammable, and is much less toxic than are many other commercially available refrigerant fluids. The system would be housed in a pressurized central compartment in a UUV equipped with a double hull (see figure). The thermodynamic cycle would begin when the UUV was at maximum depth, where some of the CO2 would condense and be stored, at relatively low temperature and pressure, in the annular volume between the inner and outer hulls. The cycle would resume once the UUV had ascended to near the surface, where the ocean temperature is typically greater than or equals 20 C. At this temperature, the CO2 previously stored at depth in the annular volume between the inner and outer hulls would be pressurized to approx. equals 57 bar (5.7 MPa). The pressurized gaseous CO2 would flow through a check valve into a bladder inside the pressurized compartment, thereby storing energy of the relatively warm, pressurized CO2 for subsequent use after the next descent to maximum depth.

  20. PHASE CHANGE MATERIALS IN FLOOR TILES FOR THERMAL ENERGY STORAGE

    Energy Technology Data Exchange (ETDEWEB)

    Douglas C. Hittle

    2002-10-01

    Passive solar systems integrated into residential structures significantly reduce heating energy consumption. Taking advantage of latent heat storage has further increased energy savings. This is accomplished by the incorporation of phase change materials into building materials used in passive applications. Trombe walls, ceilings and floors can all be enhanced with phase change materials. Increasing the thermal storage of floor tile by the addition of encapsulated paraffin wax is the proposed topic of research. Latent heat storage of a phase change material (PCM) is obtained during a change in phase. Typical materials use the latent heat released when the material changes from a liquid to a solid. Paraffin wax and salt hydrates are examples of such materials. Other PCMs that have been recently investigated undergo a phase transition from one solid form to another. During this process they will release heat. These are known as solid-state phase change materials. All have large latent heats, which makes them ideal for passive solar applications. Easy incorporation into various building materials is must for these materials. This proposal will address the advantages and disadvantages of using these materials in floor tile. Prototype tile will be made from a mixture of quartz, binder and phase change material. The thermal and structural properties of the prototype tiles will be tested fully. It is expected that with the addition of the phase change material the structural properties will be compromised to some extent. The ratio of phase change material in the tile will have to be varied to determine the best mixture to provide significant thermal storage, while maintaining structural properties that meet the industry standards for floor tile.

  1. The thermal solar energy - September 2010; Le solaire thermodynamique

    Energy Technology Data Exchange (ETDEWEB)

    Acket, C.

    2010-07-01

    The author first notices that the use of solar heat to produce electricity is much lesser known than the production of electricity by photovoltaic effect. He also notices that few efforts have been made in France to develop this technology (thermal solar energy, also called helio-thermodynamics). He evokes the Themis project and also some initiatives in Spain and in California. He recalls some data about solar heat, presents the solar concentration technique which either uses a parabolic configuration (point focus concentration) or a cylindrical and parabolic configuration (line concentration system). He briefly presents the different techniques used to transform solar heat into electricity and to store the electricity. He briefly presents different solutions which have been tested over the past years in France, Germany, Spain, California and Israel (tower and air, gas and Stirling cycle, tower and direct vapour production, cylindrical-parabolic collector). He discusses the effect of intermittency and the French context, and questions and discusses the choice between thermal and photovoltaic solar energy (advantages and drawbacks)

  2. Simulation of diurnal thermal energy storage systems: Preliminary results

    Science.gov (United States)

    Katipamula, S.; Somasundaram, S.; Williams, H. R.

    1994-12-01

    This report describes the results of a simulation of thermal energy storage (TES) integrated with a simple-cycle gas turbine cogeneration system. Integrating TES with cogeneration can serve the electrical and thermal loads independently while firing all fuel in the gas turbine. The detailed engineering and economic feasibility of diurnal TES systems integrated with cogeneration systems has been described in two previous PNL reports. The objective of this study was to lay the ground work for optimization of the TES system designs using a simulation tool called TRNSYS (TRaNsient SYstem Simulation). TRNSYS is a transient simulation program with a sequential-modular structure developed at the Solar Energy Laboratory, University of Wisconsin-Madison. The two TES systems selected for the base-case simulations were: (1) a one-tank storage model to represent the oil/rock TES system; and (2) a two-tank storage model to represent the molten nitrate salt TES system. Results of the study clearly indicate that an engineering optimization of the TES system using TRNSYS is possible. The one-tank stratified oil/rock storage model described here is a good starting point for parametric studies of a TES system. Further developments to the TRNSYS library of available models (economizer, evaporator, gas turbine, etc.) are recommended so that the phase-change processes is accurately treated.

  3. Improvement of Borehole Thermal Energy Storage Design Based on Experimental and Modelling Results

    OpenAIRE

    Lanini, Sandra; Delaleux, Fabien; Py, Xavier; Olivès, Régis; Nguyen, Denis

    2014-01-01

    Underground Thermal Energy Storage appears to be an attractive solution for solar thermal energy storage. The SOLARGEOTHERM research project aimed to evaluate the energetic potential of borehole thermal energy storage by means of a full-scale experimental device and heat transfer models. Analysis of the experimental data showed that a single borehole is not efficient for storage. Models showed that the heat transfer fluid in the geothermal probe lost 15 per cent of its energy at a depth of 10...

  4. U.S. Department of Energy thermal energy storage research activities review: 1989 Proceedings

    Energy Technology Data Exchange (ETDEWEB)

    Hoffman, H.W. [ed.] [PAI Corp., Oak Ridge, TN (United States); Tomlinson, J.J. [ed.] [Oak Ridge National Lab., TN (United States)

    1989-03-01

    Thermal Energy Storage (TES) offers the opportunity for the recovery and re-use of heat currently rejected to the ambient environment. Further, through the ability of TES to match an energy supply with a thermal energy demand, TES increases efficiencies of energy systems and improves capacity factors of power plants. The US Department of Energy has been the leader in TES research, development, and demonstration since recognition in 1976 of the need for fostering energy conservation as a component of the national energy budget. The federal program on TES R and D is the responsibility of the Office of Energy Storage and Distribution within the US Department of Energy (DOE). The overall program is organized into three program areas: diurnal--relating primarily to lower temperature heat for use in residential and commercial buildings on a daily cycle; industrial--relating primarily to higher temperature heat for use in industrial and utility processes on an hourly to daily cycle; seasonal--relating primarily to lower temperature heat or chill for use in residential complexes (central supply as for apartments or housing developments), commercial (light manufacturing, processing, or retail), and industrial (space conditioning) on a seasonal to annual cycle. Selected papers are indexed separately for inclusion in the Energy Science and Technology Database.

  5. Technical and economic feasibility of thermal energy storage. Annual report

    Energy Technology Data Exchange (ETDEWEB)

    Glenn, D.R.

    1976-02-01

    This study provides a first-look at the system elements involved in: (1) creating a market; (2) understanding and deriving the requirements; (3) performing analytical effort; (4) specifying equipment; and (5) synthesizing applications for a thermal energy storage (TES) function. The work reviews implicated markets, energy consumption patterns, TES technologies, and applications. Further, several concepts are developed and evaluated in some detail. Key findings are: (1) there are numerous technical opportunities for TES in the residential and industrial market sectors; (2) apart from sensible heat storage and transfer, significant R and D is required to fully exploit the superior heat densities of latent heat-based TES systems, particularly at temperatures above 600/sup 0/F; (3) industrial energy conservation can be favorably impacted by TES where periodic or batch-operated unit functions characterize product manufacturing processes, i.e. bricks, steel, and ceramics; and (4) a severe data shortage exists for describing energy consumption rates in real time as related to plant process operations--a needed element in designing TES systems.

  6. Thermal indoor environment and energy consumption in a plus-energy house: cooling season measurements

    OpenAIRE

    Kazanci, Ongun Berk; Olesen, Bjarne W.

    2015-01-01

    The present study is concerned with the thermal indoor environment and HVAC system energy consumption of a detached, one-story, single family, plus-energy house during a cooling season. The house was located in Denmark and it has been used as a full-scale experimental facility for one year. The house was cooled by a floor cooling system and was ventilated with a mechanical ventilation system. Different operative temperature set-points and different ventilation rates were tested. Operative tem...

  7. Measurements of the interfacial fracture energy of thermal barrier coatings

    International Nuclear Information System (INIS)

    Thermal barrier coatings (TBCs) have been extensively used in aircraft engines for improved durability and performance for more than 15 years. In this study, chevron-notched sandwich specimens proposed recently by Shaw are chosen for the study of the interfacial fracture energy of TBCs. The specimen of this kind has been successfully used to quantify the fracture energy of TBCs. The specimen of this kind has been successfully used to quantify the fracture energy of several metal/oxide and metal/silicide interfaces. The main advantages of this test specimen are: (1) it provides a rigorous fracture mechanics quantification for the bimaterial interface; (2) the fracture energy obtained arises mainly from the chemical bonding at the interface; (3) the test specimen is easy to fabricate (either diffusion or adhesive bonding), and the test is easy to implement (e.g., neither fatigue precracking nor crack length monitoring is needed); (4) no special compliance calibration of specimens is necessary because previously developed compliance calibrations for homogeneous materials can be utilized directly; (5) the test specimen is suitable for the fracture energy measurement of a single interface as well as for interfacial regions composed of several discrete interfaces, which is often the case for TBCs; and (6) the test method allows the interfacial fracture energy of TBCs to be found independent of the poorly characterized TBCs' elastic modulus as to which there is great uncertainty (e.g., the modulus in tension may be different then in compression). As will be shown in this study, all the aforementioned advantages are maintained for TBCs. Furthermore, the failure location using the chevron notched sandwich specimen duplicates the service failure mode. Thus, the data obtained can be utilized directly for lifetime prediction modeling

  8. Estimation of Wasted Thermal Energy from Gas Turbine Units in Mosul Power Station

    OpenAIRE

    Dr. A. R. Al-Habbo; A.Youns Fathi

    2012-01-01

    The present study involve a thermal analysis of a gas turbine unit like those which are used in Mosul gas turbine power station in order to estimate the amount of thermal energy is wasted in the exhaust gases. A computer program is developed to investigate the effect of ambient temperature on the performance of the gas turbine unit including the mass flow of air, power output, thermal efficiency, specific fuel consumption, exhaust gas temperature and the amount of wasted thermal energy (Qexh)...

  9. Energy supply technologies. Thermal fuel conversion pyrolysis, gasification and combustion

    Energy Technology Data Exchange (ETDEWEB)

    Frandsen, Flemming J.; Jensen, Anker; Jensen, Peter A.; Glarborg, P.; Dam-Johansen, K. [DTU (Denmark)

    2007-11-15

    The basic idea in thermal conversion of fuels is to transform and utilize chemical energy bound in the fuel to e.g. supersaturated steam in steam cycle, from which electricity may be produced upon passage of a steam turbine. Anyhow, thermal conversion of solid fuels occur, in principle, either in one strongly exothermic step from fuel to fully oxidized species, or in multiple steps, initiated by an endothermic step, in which a calorific gas is produced, followed by multiple exothermic conversion steps. The difference between these extremes provides possibilities of heat and power production, combined with application of gaseous products for production of liquid fuels. Recently, several opportune concepts of combined thermal conversion and fuel production have been introduced. Recommendations for future research areas: 1) Further development of pressurized gasifiers to handle biomass and waste as well as co-gasification of biomass and coal. 2) Work on integration of the gas-to-liquid (GLT) technology with power production so that waste heat can be used efficiently for power and central heat production. Integration with other advanced technologies so outlet CO{sub 2}-sequestration can be obtained and that the gasification can be integrated with combined cycle power production. 3) Increase of plant efficiency by improving the efficiency of both the gasification and synthesis process. 4) Development of new catalysts, with higher tolerance towards poisoning, and improved control over product composition. 5) Development and test of motors, and distribution systems, for new fuel types. There are several incitements to provide alternative transport fuels based on biomass as a raw material. It will be a CO{sub 2}-neutral transport fuel, it will reduce the dependence on imported fossil fuels in the Western world, and it is possible to further develop a domestic industry based on liquid fuels. (BA)

  10. Strategies for commercializing customer thermal-energy storage. [64 references

    Energy Technology Data Exchange (ETDEWEB)

    Nelson, S.H.

    1976-12-01

    This report presents strategies for commercializing customer thermal storage. Four storage techniques are evaluated: space heating, air conditioning, hot-water heating, and interruptible hot-water heating. The storage systems involved store off-peak electric energy for thermal applications during peak load hours. Analyses of both storage techniques and principal parties affected by storage indicate four barriers: the absence of (1) commercially available air conditioning storage devices, (2) appropriate rates, (3) information on both rates and devices, and (4) widespread utility support. Development of appropriate rates is the key to commercialization. The criteria used to evaluate rate types are: maximum combined utility and customer benefits, ease of commercialization, and practical feasibility. Four rate types--demand charges, time-of-use rates, and two forms of load management rates (a monthly credit and an off-peak discount)--plus the possibility of utility ownership are considered. The best rate types for each storage option are: for hot-water heating, a monthly credit for allowing utility interruptions or an off-peak price discount for storage; for space heating, an off-peak discount contingent upon meeting utility requirements; and for air conditioning, an off-peak discount plus monthly credit.

  11. Sustainability and policy for the thermal use of shallow geothermal energy

    International Nuclear Information System (INIS)

    Shallow geothermal energy is a renewable energy resource that has become increasingly important. However, the use has environmental, technical and social consequences. Biological, chemical, and physical characteristics of groundwater and subsurface are influenced by the development of this resource. To guarantee a sustainable use it is therefore necessary to consider environmental and technical criteria, such as changes in groundwater quality and temperature. In the current study a comprehensive overview of consequences of geothermal systems in shallow aquifers is provided. We conclude that there is still a lack of knowledge on long-term environmental consequences. Due to local differences in geology and hydrogeology as well as in technical requirements, it is not recommendable to define only static regulations, such as fixed and absolute temperature thresholds. Flexible temperature limits for heating and cooling the groundwater and subsurface are therefore advisable. The limits should be oriented on previously undisturbed temperatures, and chemical, physical and biological conditions of aquifers. Based on these findings, recommendations for a sustainable policy for shallow geothermal systems are provided including a potential legal framework for a sustainable use. - Highlights: • We provide an overview of consequences of geothermal systems in shallow aquifers. • Static regulations for heating or cooling groundwater are not recommendable. • Temperature limits should be flexible and orientated on background values. • Suggestions for a sustainable policy for shallow geothermal systems are provided. • A potential legal framework for a sustainable use is presented

  12. Analysis of thermal energy harvesting using ferromagnetic materials

    International Nuclear Information System (INIS)

    This Letter aims at giving a preliminary investigation of the thermal energy harvesting capabilities of a technique using the temperature-dependent permeability of ferromagnetic materials. The principles lie in the modification of the magnetic field caused by the variation of the permeability due to the temperature change, hence generating a voltage across a coil surrounding the circuit. The technique can be made truly passive by the use of magnets for applying bias magnetic field. Theoretical results, validated by experimental measurements, show a voltage output of 1.2 mV at optimal load of 2 Ω under 60 K temperature variation in 5 s (with a maximum slope of 25 K s−1). Further improvements, such as the use of low resistivity coil and magnet with high remnant magnetic field, indicate that it is possible to convert up to 7.35 μJ cm−3 K−2 cycle−1. - Highlights: • Ferromagnetic materials show a sharp change in their permeability near the Curie temperature. • A bias magnetic field permits changing the magnetic flux with the temperature. • The variable magnetic flux can be converted into electrical energy by using a coil. • Theoretical and experimental measurements show an energy density up to 7.35 μJ cm−3 K−2 cycle−1. • Optimization issues should focus on coil quality and global magnetic reluctance variation

  13. Thermal energy storage systems using fluidized bed heat exchangers

    Science.gov (United States)

    Weast, T.; Shannon, L.

    1980-01-01

    A rotary cement kiln and an electric arc furnace were chosen for evaluation to determine the applicability of a fluid bed heat exchanger (FBHX) for thermal energy storage (TES). Multistage shallow bed FBHX's operating with high temperature differences were identified as the most suitable for TES applications. Analysis of the two selected conceptual systems included establishing a plant process flow configuration, an operational scenario, a preliminary FBHX/TES design, and parametric analysis. A computer model was developed to determine the effects of the number of stages, gas temperatures, gas flows, bed materials, charge and discharge time, and parasitic power required for operation. The maximum national energy conservation potential of the cement plant application with TES is 15.4 million barrels of oil or 3.9 million tons of coal per year. For the electric arc furnance application the maximum national conservation potential with TES is 4.5 million barrels of oil or 1.1 million tons of coal per year. Present time of day utility rates are near the breakeven point required for the TES system. Escalation of on-peak energy due to critical fuel shortages could make the FBHX/TES applications economically attractive in the future.

  14. Influence of nanomaterials on properties of latent heat solar thermal energy storage materials – A review

    International Nuclear Information System (INIS)

    Highlights: • Classification of phase change materials. • Studies on phase change properties of various phase change materials. • Influence of nanomaterials on properties of phase change materials. - Abstract: Thermal energy storage system plays a critical role in developing an efficient solar energy device. As far as solar thermal devices are concerned, there is always a mismatch between supply and demand due to intermittent and unpredictable nature of solar radiation. A well designed thermal energy storage system is capable to alleviate this demerit by providing a constant energy delivery to the load. Many research works is being carried out to determine the suitability of thermal energy storage system to integrate with solar thermal gadgets. This review paper summarizes the numerous investigations on latent heat thermal energy storage using phase change materials (PCM) and its classification, properties, selection criteria, potential research areas and studies involved to analyze the thermal–physical properties of PCM

  15. Thermal energy and bootstrap current in fusion reactor plasmas

    International Nuclear Information System (INIS)

    For DT fusion reactors with prescribed alpha particle heating power Pα, plasma volume V and burn temperature i> ∼ 10 keV specific relations for the thermal energy content, bootstrap current, central plasma pressure and other quantities are derived. It is shown that imposing Pα and V makes these relations independent of the magnitudes of the density and temperature, i.e. they only depend on Pα, V and shape factors or profile parameters. For model density and temperature profiles analytic expressions for these shape factors and for the factor Cbs in the bootstrap current formula Ibs ∼ Cbs(a/R)1/2βpIp are given. In the design of next-step devices and fusion reactors, the fusion power is a fixed quantity. Prescription of the alpha particle heating power and plasma volume results in specific relations which can be helpful for interpreting computer simulations and for the design of fusion reactors. (author) 5 refs

  16. Shelf mounted ocean thermal energy conversion platform, revised preliminary report

    Science.gov (United States)

    1984-03-01

    This report relates model tests of a generic Ocean Thermal Energy Conversion (OTEC) platform. The objective of these tests is to aid in the evaluation of new OTEC designs and to present a data base for design purposes. The test plant has been designed to provide a data base for comparison with current and projected analytical tools as well as comparisons of results from one model configuration to another. The new conceptual OTEC designs are different from the typical offshore (jacket type) structure which is quite transparent to waves. The major difference is the addition of large submerged power production modules to the frame. These proposed modules offer a large surface area to obstruct the flow and thereby increase the global wave forces acting on the structure.

  17. Flight experiment of thermal energy storage. [for spacecraft power systems

    Science.gov (United States)

    Namkoong, David

    1989-01-01

    Thermal energy storage (TES) enables a solar dynamic system to deliver constant electric power through periods of sun and shade. Brayton and Stirling power systems under current considerations for missions in the near future require working fluid temperatures in the 1100 to 1300+ K range. TES materials that meet these requirements fall into the fluoride family of salts. Salts shrink as they solidify, a change reaching 30 percent for some salts. Hot spots can develop in the TES container or the container can become distorted if the melting salt cannot expand elsewhere. Analysis of the transient, two-phase phenomenon is being incorporated into a three-dimensional computer code. The objective of the flight program is to verify the predictions of the code, particularly of the void location and its effect on containment temperature. The four experimental packages comprising the program will be the first tests of melting and freezing conducted under microgravity.

  18. Full-energy-chain analysis of greenhouse gas emissions for solar thermal electric power generation systems

    International Nuclear Information System (INIS)

    Technical attributes and environmental impacts of solar thermal options for centralized electricity generation are discussed. In particular, the full-energy-chain, including embodied energy and energy production, is considered in relation to greenhouse gas emission arising from solar thermal electricity generation. Central receiver, parabolic dish, parabolic trough and solar pond systems are considered. (author)

  19. Correlation of energy and free energy for the thermal Casimir force between real metals

    International Nuclear Information System (INIS)

    The energy of a fluctuating electromagnetic field is investigated for the thermal Casimir force acting between parallel plates made of a real metal. It is proved that for nondissipative media with temperature-independent dielectric permittivity the energy at nonzero temperature comprises the (renormalized) energies of the zero-point and thermal photons. In this manner photons can be considered as collective elementary excitations of the matter of plates and electromagnetic field. If the dielectric permittivity depends on temperature, the energy contains additional terms proportional to the derivatives of ε with respect to temperature, and the quasiparticle interpretation of the fluctuating field is not possible. The correlation between energy and free energy is considered. Previous calculations of the Casimir energy in the framework of the Lifshitz formula at zero temperature and optical tabulated data supplemented by the Drude model at room temperature are analyzed. It is demonstrated that this quantity is not a good approximation either for the free energy or the energy. A physical interpretation of this hybrid quantity is suggested. The contradictory results in the recent literature on whether the zero-frequency term of the Lifshitz formula for the perpendicular polarized modes has any effective contribution to the physical quantities are discussed. Four main approaches to the resolution of this problem are specified. The precise expressions for entropy of the fluctuating field between plates made of a real metal are obtained, which helps to decide between the different approaches. The conclusion is that the Lifshitz formula supplemented by the plasma model and the surface impedance approach are best suited to describe the thermal Casimir force between real metals

  20. Nonimaging concentrators for solar thermal energy. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Winston, R.

    1980-03-21

    A small experimental solar collector test facility has been established on the campus of the University of Chicago. This capability has been used to explore applications of nonimaging optics for solar thermal concentration in three substantially different configurations: (1) a single stage system with moderate concentration on an evacuated absorber (a 5.25X evacuated tube Compound Parabolic Concentrator or CPC), (2) a two stage system with high concentration and a non-evacuated absorber (a 16X Fresnel lens/CPC type mirror) and (3) moderate concentration single stage systems with non-evacuated absorbers for lower temperature (a 3X and a 6.5X CPC). Prototypes of each of these systems have been designed, built and tested. The performance characteristics are presented. In addition a 73 m/sup 2/ experimental array of 3X non-evacuated CPC's has been installed in a school heating system on the Navajo Indian Reservation in New Mexico. The full array has a peak noon time efficiency of approx. 50% at ..delta..T = 50/sup 0/C above ambient and has supplied about half the school's heat load for the past two heating seasons. Several theoretical features of nonimaging concentration have been investigated including their long term energy collecting behavior. The measured performance of the different systems shows clearly that non-tracking concentrators can provide solar thermal energy from moderately high low temperature regimes (> 50/sup 0/C above ambient) up into the mid-temperature region (well above 200/sup 0/C above ambient). The measured efficiency at 220/sup 0/C for the 5.25X CPC was as high or higher than that for any of the commercial tracking systems tested.

  1. Timescale and magnitude of plasma thermal energy loss before and during disruptions in JET

    Science.gov (United States)

    Riccardo, V.; Loarte, A.; JET EFDA Contributors

    2005-11-01

    In this paper we analyse and discuss the thermal energy loss dynamics before and during JET disruptions that occurred between 2002 and 2004 in discharges which reached >4.5 MJ of thermal energy. We observe the slow thermal energy transients with diamagnetic loops and the fast ones with electron cyclotron emission and soft x-ray diagnostics. For most disruption types in JET, the plasma thermal energy at the time of the thermal quench is substantially less than that of the full performance plasma, typically in the range of 10-50% depending on plasma conditions and disruption type. The exceptions to this observation are disruptions in plasmas with a strong internal transport barrier (ITB) and in discharges terminating in a pure vertical displacement event, in which the plasma conserves a very high energy content up to the thermal quench. These disruption types are very sudden, leaving little scope for the combined action of soft plasma landing strategies and intrinsic performance degradation, both requiring >500 ms to be effective, to decrease the available thermal energy. The characteristic time for the loss of energy from the main plasma towards the PFCs in the thermal quench of JET disruptions is in the range 0.05-3.0 ms. The shortest timescales are typical of disruptions caused by excessive pressure peaking in ITB discharges. The available thermal energy fraction and thermal quench duration observed in JET can be processed (with due caution) into estimates for the projected PFC lifetime of the ITER target.

  2. Timescale and magnitude of plasma thermal energy loss before and during disruptions in JET

    International Nuclear Information System (INIS)

    In this paper we analyse and discuss the thermal energy loss dynamics before and during JET disruptions that occurred between 2002 and 2004 in discharges which reached >4.5 MJ of thermal energy. We observe the slow thermal energy transients with diamagnetic loops and the fast ones with electron cyclotron emission and soft x-ray diagnostics. For most disruption types in JET, the plasma thermal energy at the time of the thermal quench is substantially less than that of the full performance plasma, typically in the range of 10-50% depending on plasma conditions and disruption type. The exceptions to this observation are disruptions in plasmas with a strong internal transport barrier (ITB) and in discharges terminating in a pure vertical displacement event, in which the plasma conserves a very high energy content up to the thermal quench. These disruption types are very sudden, leaving little scope for the combined action of soft plasma landing strategies and intrinsic performance degradation, both requiring >500 ms to be effective, to decrease the available thermal energy. The characteristic time for the loss of energy from the main plasma towards the PFCs in the thermal quench of JET disruptions is in the range 0.05-3.0 ms. The shortest timescales are typical of disruptions caused by excessive pressure peaking in ITB discharges. The available thermal energy fraction and thermal quench duration observed in JET can be processed (with due caution) into estimates for the projected PFC lifetime of the ITER target

  3. Dynamic Stability Analysis of the Hybrid System Designed for Ocean Thermal Energy Conversion and Thermal Power Plant

    Directory of Open Access Journals (Sweden)

    Mohammad Ali Azghandi

    2014-05-01

    Full Text Available Oceanic Thermal Energy Conversion (OTEC is a method for generating electricity by taking advantage of the small temperature difference between warm surface water and cold deep ocean water. In the present research, we have studied and assessed dynamic stability and performance simulation of an OTEC power plant whose thermal efficiency has been improved by absorbing the thermal energy of the steam input to the condenser of a thermal power plant which should be discharged through cooling water. The mathematic models of the system have been developed based on its thermodynamic properties as well as on the structure of its power cycle so that it has become possible to carry out dynamic simulation and assessment on the system. The proposed systems are potentially able to increase the net thermal efficiency, and at the same time, reduce the thermal pollution created. Dynamic equations of the systems under study have been developed in the conditions created by equilibrium between three phases. Transient response of the hybrid system with the thermal power plant to disturbances such as sudden changes in load and short-circuit fault has been evaluated. Results indicate suggest that increase in thermal productivity of the system cause system to have desirable steady state and transient performance

  4. Preparation, thermal properties and thermal reliabilities of microencapsulated n-octadecane with acrylic-based polymer shells for thermal energy storage

    International Nuclear Information System (INIS)

    Highlights: ► n-Octadecane was encapsulated by p(butyl methacrylate) (PBMA) and p(butyl acrylate). ► Microcapsules using divinylbenzene as crosslinking agent have better quality. ► Microcapsule with butyl methacrylate–divinylbenzene has highest latent heat. ► Microcapsule with butyl methacrylate–divinylbenzene has greatest thermal stability. ► Phase change temperatures and enthalpies of the microcapsules varied little after thermal cycle. - Abstract: Microencapsulation of n-octadecane with crosslinked p(butyl methacrylate) (PBMA) and p(butyl acrylate) (PBA) as shells for thermal energy storage was carried out by a suspension-like polymerization. Divinylbenzene (DVB) and pentaerythritol triacrylate (PETA) were employed as crosslinking agents. The surface morphologies of the microencapsulated phase change materials (microPCMs) were studied by scanning electron microscopy (SEM). Thermal properties, thermal reliabilities and thermal stabilities of the as-prepared microPCMs were investigated by differential scanning calorimetry (DSC) and thermal gravimetric analysis (TGA). The microPCMs prepared by using DVB exhibit greater heat capacities and higher thermal stabilities compared with those prepared by using PETA. The thermal resistant temperature of the microPCM with BMA–DVB polymer was up to 248 °C. The phase change temperatures and latent heats of all the as-prepared microcapsules varied little after 1000 thermal cycles.

  5. Preparation, thermal properties and thermal reliabilities of microencapsulated n-octadecane with acrylic-based polymer shells for thermal energy storage

    Energy Technology Data Exchange (ETDEWEB)

    Qiu, Xiaolin [Advanced Materials Institute and Clearer Production Key Laboratory, Graduate School at Shenzhen, Tsinghua University, Shenzhen 518055 (China); Key Laboratory of Advanced Materials, Department of Materials Science and Engineering, Tsinghua University, Haidian District, Beijing 100084 (China); Song, Guolin; Chu, Xiaodong; Li, Xuezhu [Advanced Materials Institute and Clearer Production Key Laboratory, Graduate School at Shenzhen, Tsinghua University, Shenzhen 518055 (China); Tang, Guoyi, E-mail: tanggy@tsinghua.edu.cn [Advanced Materials Institute and Clearer Production Key Laboratory, Graduate School at Shenzhen, Tsinghua University, Shenzhen 518055 (China); Key Laboratory of Advanced Materials, Department of Materials Science and Engineering, Tsinghua University, Haidian District, Beijing 100084 (China)

    2013-01-10

    Highlights: Black-Right-Pointing-Pointer n-Octadecane was encapsulated by p(butyl methacrylate) (PBMA) and p(butyl acrylate). Black-Right-Pointing-Pointer Microcapsules using divinylbenzene as crosslinking agent have better quality. Black-Right-Pointing-Pointer Microcapsule with butyl methacrylate-divinylbenzene has highest latent heat. Black-Right-Pointing-Pointer Microcapsule with butyl methacrylate-divinylbenzene has greatest thermal stability. Black-Right-Pointing-Pointer Phase change temperatures and enthalpies of the microcapsules varied little after thermal cycle. - Abstract: Microencapsulation of n-octadecane with crosslinked p(butyl methacrylate) (PBMA) and p(butyl acrylate) (PBA) as shells for thermal energy storage was carried out by a suspension-like polymerization. Divinylbenzene (DVB) and pentaerythritol triacrylate (PETA) were employed as crosslinking agents. The surface morphologies of the microencapsulated phase change materials (microPCMs) were studied by scanning electron microscopy (SEM). Thermal properties, thermal reliabilities and thermal stabilities of the as-prepared microPCMs were investigated by differential scanning calorimetry (DSC) and thermal gravimetric analysis (TGA). The microPCMs prepared by using DVB exhibit greater heat capacities and higher thermal stabilities compared with those prepared by using PETA. The thermal resistant temperature of the microPCM with BMA-DVB polymer was up to 248 Degree-Sign C. The phase change temperatures and latent heats of all the as-prepared microcapsules varied little after 1000 thermal cycles.

  6. Influence of reflectance from flat aluminum concentrators on energy efficiency of PV/Thermal collector

    International Nuclear Information System (INIS)

    In this paper the results of the influence of reflectance from flat plate solar radiation concentrators made of Al sheet and Al foil on energy efficiency of PV/Thermal collector are presented. The total reflectance from concentrators made of Al sheet and Al foil is almost the same, but specular reflectance which is bigger in concentrators made of Al foil results in increase of solar radiation intensity concentration factor. With the increase of solar radiation intensity concentration factor, total daily thermal and electrical energy generated by PV/Thermal collector with concentrators increase. In this work also optimal position of solar radiation concentrators made of Al sheet and Al foil and appropriate thermal and electrical efficiency of PV/Thermal collector have been determined. Total energy generated by PV/Thermal collector with concentrators made of Al foil in optimal position is higher than total energy generated by PV/Thermal collector with concentrators made of Al sheet.

  7. DESORPTION BEHAVIOR OF TRICHLOROETHENE AND TETRACHLOROETHENE IN U.S. DEPARTMENT OF ENERGY SAVANNAH RIVER SITE UNCONFINED AQUIFER SEDIMENTS

    International Nuclear Information System (INIS)

    Sorption is governed by the physico-chemical processes that partition solutes between the aqueous and solid phases in aquifers. For environmental systems, a linear equilibrium relationship between the amount of contaminant in the alternative phases is often assumed. In this traditional approach, the distribution coefficient, or Kd, is a ratio of contaminant associated with the solid phase to the contaminant in the water phase. Recent scientific literature has documented time-dependant behaviors in which more contaminant mass is held in the solid phase than predicted by the standard model. Depending on the specific conceptualization, this has been referred to as nonlinear sorption, time-variable sorption, or ''irreversible sorption''. The potential impact of time-variable sorption may be beneficial or detrimental depending on the specific conditions and remediation goals. Researchers at the Pacific Northwest National Laboratory (PNNL) have been studying this process to evaluate how various soil types will affect this process for sites contaminated with chlorinated solvents. The results described in this report evaluate sorption-desorption of trichloroethylene (TCE) and tetrachloroethylene (PCE) in Savannah River Site (SRS) soils. The results of this study will be combined with ongoing PNNL research to provide a more comprehensive look at this process and its impact on contaminant plume stability and sustainability. Importantly, while the results of the study documented differences in sorption properties between two tested SRS soils, the data indicated that ''irreversible sorption'' is not influencing the sorption-desorption behaviors of TCE and PCE for these soils

  8. Renewable energy distributed power system with photovoltaic/ thermal and bio gas power generators

    International Nuclear Information System (INIS)

    The energy shortage and environmental pollution is becoming an important problem in these days. Hence it is very much important to use renewable power technologies to get rid of these problems. The important renewable energy sources are Bio-Energy, Wind Energy, Hydrogen Energy, Tide Energy, Terrestrial Heat Energy, Solar Energy, Thermal Energy and so on. Pakistan is rich in all these aspects particularly in Solar and Thermal Energies. In major areas of Pakistan like in South Punjab, Sind and Baluchistan the weather condition are very friendly for these types of Renewable Energies. In these areas Solar Energy can be utilized by solar panels in conjunction with thermal panels. The Photovoltaic cells are used to convert Solar Energy directly to Electrical Energy and thermal panels can be uses to convert solar energy into heat energy and this heat energy will be used to drive some turbine to get Electrical Energy. The Solar Energy can be absorbed more efficiently by any given area of Solar Panel if these two technologies can be combined in such a way that they can work together. The first part of this paper shows that how these technologies can be combined. Furthermore it is known to all that photovoltaic/thermal panels depend entirely on weather conditions. So in order to maintain constant power a biogas generator is used in conjunction with these. (author)

  9. Applications of thermal energy storage to process heat and waste heat recovery in the primary aluminum industry. Final report, September 1977-September 1978

    Energy Technology Data Exchange (ETDEWEB)

    Katter, L.B.; Hoskins, R.L.

    1979-04-01

    The results of a study entitled, Applications of Thermal Energy Storage to Process Heat and Waste Heat Recovery in the Primary Aluminum Industry are presented. In this preliminary study, a system has been identified by which the large amounts of low-grade waste energy in the primary pollution control system gas stream can be utilized for comfort heating in nearby communities. Energy is stored in the form of hot water, contained in conventional, insulated steel tanks, enabling a more efficient utilization of the constant energy source by the cyclical energy demand. Less expensive energy storage means (heated ponds, aquifers), when they become fully characterized, will allow even more cost-competitive systems. Extensive design tradeoff studies have been performed. These tradeoff studies indicate that a heating demand equivalent to 12,000 single-family residences can be supplied by the energy from the Intalco plant. Using a 30-year payback criterion (consistent with utility planning practice), the average cost of energy supplied over the system useful life is predicted at one-third the average cost of fossil fuel. The study clearly shows that the utilization of waste energy from aluminum plants is both technically and economically attractive. The program included a detailed survey of all aluminum plants within the United States, allowing the site specific analyses to be extrapolated to a national basis. Should waste heat recovery systems be implemented by 1985, a national yearly savings of 6.5 million barrels of oil can be realized.

  10. Review on thermal performance of phase change energy storage building envelope

    Institute of Scientific and Technical Information of China (English)

    WANG Xin; ZHANG YinPing; XlAO Wei; ZENG RuoLang; ZHANG QunLi; DI HongFa

    2009-01-01

    Improving the thermal performance of building envelope is an important way to save building energy consumption. The phase change energy storage building envelope is helpful to effective use of renewable energy, reducing building operational energy consumption, increasing building thermal comfort, and reducing environment pollution and greenhouse gas emission. This paper presents the concept of ideal energy-saving building envelope, which is used to guide the building envelope material selection and thermal performance design. This paper reviews some available researches on phase change building material and phase change energy storage building envelope. At last, this paper presents some current problems needed further research.

  11. Technologies for power and thermal energy generation. Bring our energies together

    International Nuclear Information System (INIS)

    On behalf of ADEME, the DREAL and the Region of Brittany and produced by ENEA, consulting company in energy and sustainable development, this brochure presents main technologies for power and thermal energy generation in an effort to maintain objectivity (efficiency, intrinsic features of each technology and key figures as regards power and energy). If most of the technologies are operational or in development in Brittany, such as ocean energy, the scope has been extended to encompass all existing technologies in France in order to give useful references. The French Brittany is a peninsula, with regards to both its geographic situation and its energy context. The region has decided to investigate energy and climate issue through the Brittany Energy Conference and to commit for energy transition. Discussions which have taken place since 2010 at the regional level as well as the national debate on energy transition in 2013 have highlighted the need for educational tools for the main energy generation technologies. Thus, the purpose of this brochure is to share energy stakes with a broad audience

  12. Salinization in a stratified aquifer induced by heat transfer from well casings

    Science.gov (United States)

    van Lopik, Jan H.; Hartog, Niels; Zaadnoordijk, Willem Jan; Cirkel, D. Gijsbert; Raoof, Amir

    2015-12-01

    The temperature inside wells used for gas, oil and geothermal energy production, as well as steam injection, is in general significantly higher than the groundwater temperature at shallower depths. While heat loss from these hot wells is known to occur, the extent to which this heat loss may result in density-driven flow and in mixing of surrounding groundwater has not been assessed so far. However, based on the heat and solute effects on density of this arrangement, the induced temperature contrasts in the aquifer due to heat transfer are expected to destabilize the system and result in convection, while existing salt concentration contrasts in an aquifer would act to stabilize the system. To evaluate the degree of impact that may occur under field conditions, free convection in a 50-m-thick aquifer driven by the heat loss from penetrating hot wells was simulated using a 2D axisymmetric SEAWAT model. In particular, the salinization potential of fresh groundwater due to the upward movement of brackish or saline water in a stratified aquifer is studied. To account for a large variety of well applications and configurations, as well as different penetrated aquifer systems, a wide range of well temperatures, from 40 to 100 °C, together with a range of salt concentration (1-35 kg/m3) contrasts were considered. This large temperature difference with the native groundwater (15 °C) required implementation of a non-linear density equation of state in SEAWAT. We show that density-driven groundwater flow results in a considerable salt mass transport (up to 166,000 kg) to the top of the aquifer in the vicinity of the well (radial distance up to 91 m) over a period of 30 years. Sensitivity analysis showed that density-driven groundwater flow and the upward salt transport was particularly enhanced by the increased heat transport from the well into the aquifer by thermal conduction due to increased well casing temperature, thermal conductivity of the soil, as well as decreased

  13. Design and installation manual for thermal energy storage

    Energy Technology Data Exchange (ETDEWEB)

    Cole, R L; Nield, K J; Rohde, R R; Wolosewicz, R M [eds.

    1979-02-01

    The purpose for this manual is to provide information on the design and installation of thermal energy storage in solar heating systems. It is intended for contractors, installers, solar system designers, engineers, architects, and manufacturers who intend to enter the solar energy business. The reader should have general knowledge of how solar heating systems operate and knowledge of construction methods and building codes. Knowledge of solar analysis methods such as f-chart, SOLCOST, DOE-1, or TRNSYS would be helpful. The information contained in the manual includes sizing storage, choosing a location for the storage device, and insulation requirements. Both air-based and liquid-based systems are covered with topics on designing rock beds, tank types, pump and fan selection, installation, costs, and operation and maintenance. Topics relevant to heating domestic water include safety, single- and dual-tank systems, domestic water heating with air- and liquid-based space heating system, and stand-alone domestic hot water systems. Several appendices present common problems with storage systems and their solutions, heat transfer fluid properties, heat exchanger sizing, and sample specifications for heat exchangers, wooden rock bins, steel tanks, concrete tanks, and fiberglass-reinforced plastic tanks.

  14. Multicriteria analysis of thermal and energy systems for tourist facilities

    International Nuclear Information System (INIS)

    The introductory part of the paper briefly presents the technological, economic and environmental optimisation procedure of thermal and energy systems for tourist facilities with the multicriteria ranging method when choosing an optimum solution. The procedure described includes a systematic analysis of the system's structure, energy-mass balance, balance of costs, environmental impact analysis and the choice of an optimum solution. Special attention was paid to criteria quantification for the choice of solution and the most appropriate ranging method.The procedure's application has been illustrated on an example of a potential tourist facility on the Island of Loinj, i.e. the locality with a potential highest category tourist development. This example includes (a) consumers (heating of rooms, preparation of hot water, heating of swimming pool water and cooling of rooms), and (b) producers (boiler room, cooling engine-rooms, a cogeneration plant and heat pumps). The data have been supplied from the project documentation for the reconstruction of the existing facilities mainly preliminary designs. The multicriteria ranging was conducted based on an appropriate computer programme for problem solution. (author)

  15. Enhanced photovoltaic energy conversion using thermally based spectral shaping

    Science.gov (United States)

    Bierman, David M.; Lenert, Andrej; Chan, Walker R.; Bhatia, Bikram; Celanović, Ivan; Soljačić, Marin; Wang, Evelyn N.

    2016-06-01

    Solar thermophotovoltaic devices have the potential to enhance the performance of solar energy harvesting by converting broadband sunlight to narrow-band thermal radiation tuned for a photovoltaic cell. A direct comparison of the operation of a photovoltaic with and without a spectral converter is the most critical indicator of the promise of this technology. Here, we demonstrate enhanced device performance through the suppression of 80% of unconvertible photons by pairing a one-dimensional photonic crystal selective emitter with a tandem plasma–interference optical filter. We measured a solar-to-electrical conversion rate of 6.8%, exceeding the performance of the photovoltaic cell alone. The device operates more efficiently while reducing the heat generation rates in the photovoltaic cell by a factor of two at matching output power densities. We determined the theoretical limits, and discuss the implications of surpassing the Shockley–Queisser limit. Improving the performance of an unaltered photovoltaic cell provides an important framework for the design of high-efficiency solar energy converters.

  16. Design and installation manual for thermal energy storage

    Energy Technology Data Exchange (ETDEWEB)

    Cole, R L; Nield, K J; Rohde, R R; Wolosewicz, R M

    1980-01-01

    The purpose of this manual is to provide information on the design and installation of thermal energy storage in active solar systems. It is intended for contractors, installers, solar system designers, engineers, architects, and manufacturers who intend to enter the solar energy business. The reader should have general knowledge of how solar heating and cooling systems operate and knowledge of construction methods and building codes. Knowledge of solar analysis methods such as f-Chart, SOLCOST, DOE-1, or TRNSYS would be helpful. The information contained in the manual includes sizing storage, choosing a location for the storage device, and insulation requirements. Both air-based and liquid-based systems are covered with topics on designing rock beds, tank types, pump and fan selection, installation, costs, and operation and maintenance. Topics relevant to latent heat storage include properties of phase-change materials, sizing the storage unit, insulating the storage unit, available systems, and cost. Topics relevant to heating domestic water include safety, single- and dual-tank systems, domestic water heating with air- and liquid-based space heating systems, and stand alone domestics hot water systems. Several appendices present common problems with storage systems and their solutions, heat transfer fluid properties, economic insulation thickness, heat exchanger sizing, and sample specifications for heat exchangers, wooden rock bins, steel tanks, concrete tanks, and fiberglass-reinforced plastic tanks.

  17. Thermal stability and deactivation energy of free and immobilized invertase

    Directory of Open Access Journals (Sweden)

    F.J. Bassetti

    2000-12-01

    Full Text Available The thermal stability and the energy of deactivation of free invertase and the immobilized enzyme (IE was measured at temperatures in the range of 35 to 65°C for the hydrolysis of a 5% w/v sucrose solution. The free enzyme at pH 5.0 is stable up to 50°C for a period of 4 h. Invertase immobilized in controlled pore silica by the silane-glutaraldehyde covalent method is stable up to 55ºC, in pH 4.5 for the same period. For higher temperatures the enzyme deactivation follows the exponential decay model and half-lives are 0.53, 1.80, and 13.9 h for free invertase, at 65, 60, and 55ºC, respectively. For the IE half-lives are 0.48, 1.83, and 20.9 h, at 65, 60, and 55ºC, respectively. The IE is more stable than the free invertase; the energy of deactivation being 83.1 kcal/mol for the IE and 72.0 kcal/mol for the free enzyme.

  18. Thermally activated building systems in office buildings: impact of control strategy on energy performance and thermal comfort

    OpenAIRE

    Sourbron, Maarten; Helsen, Lieve

    2010-01-01

    At the Science Park Arenberg site in Leuven (Belgium) two new office buildings equipped with thermally activated building systems (TABS) to cover the cooling load and the base heating load, are constructed. A ground coupled heat pump/direct cooling (HP/DC) system supplies heat and cold to the TABS, while a gas boiler/chiller combination feeds the air handling units. This paper evaluates the impact of the TABS control strategy on both energy consumption and thermal comfort. Furthermore, con...

  19. DESORPTION BEHAVIOR OF TRICHLOROETHENE AND TETRACHLOROETHENE IN U.S. DEPARTMENT OF ENERGY SAVANNAH RIVER SITE UNCONFINED AQUIFER SEDIMENTS

    Energy Technology Data Exchange (ETDEWEB)

    Vangelas, K; Robert G. Riley, R; James E. Szecsody, J; A. V. Mitroshkov, A; C. F. Brown, C; Brian02 Looney, B

    2007-01-10

    Sorption is governed by the physico-chemical processes that partition solutes between the aqueous and solid phases in aquifers. For environmental systems, a linear equilibrium relationship between the amount of contaminant in the alternative phases is often assumed. In this traditional approach, the distribution coefficient, or K{sub d}, is a ratio of contaminant associated with the solid phase to the contaminant in the water phase. Recent scientific literature has documented time-dependant behaviors in which more contaminant mass is held in the solid phase than predicted by the standard model. Depending on the specific conceptualization, this has been referred to as nonlinear sorption, time-variable sorption, or ''irreversible sorption''. The potential impact of time-variable sorption may be beneficial or detrimental depending on the specific conditions and remediation goals. Researchers at the Pacific Northwest National Laboratory (PNNL) have been studying this process to evaluate how various soil types will affect this process for sites contaminated with chlorinated solvents. The results described in this report evaluate sorption-desorption of trichloroethylene (TCE) and tetrachloroethylene (PCE) in Savannah River Site (SRS) soils. The results of this study will be combined with ongoing PNNL research to provide a more comprehensive look at this process and its impact on contaminant plume stability and sustainability. Importantly, while the results of the study documented differences in sorption properties between two tested SRS soils, the data indicated that ''irreversible sorption'' is not influencing the sorption-desorption behaviors of TCE and PCE for these soils.

  20. What my dogs forced me to learn about thermal energy transfer

    Science.gov (United States)

    Bohren, Craig F.

    2015-05-01

    Some objects feel colder to the touch than others at the same (room) temperature. But explaining why by linear, single-factor reasoning is inadequate because the time-dependent thermal energy transfer at solid interfaces initially at different temperatures is determined by the thermal inertia √{ k ρ c } , a function of three thermophysical properties: thermal conductivity k, density ρ, and specific heat capacity per unit mass c. In time-dependent problems 1 / √{ k ρ c } plays the role of a resistance. As an example, although the thermal conductivity of aluminum is 16 times that of stainless steel, this does not translate into a 16-fold difference in interfacial thermal energy flux densities. Nor does it result in a markedly greater perceived coldness of aluminum; the difference is barely perceptible. Similarly, despite the 600-fold difference in the thermal conductivity of iron relative to that of wood, the ratio of thermal energy flux densities is only about 4.6.

  1. Searching for an Acidic Aquifer in the Rio Tinto Basin: First Geobiology Results of MARTE Project

    Science.gov (United States)

    Fernandez-Remolar, D. C.; Prieto-Ballesteros, O.; Stoker, C.

    2004-01-01

    Among the conceivable modern habitats to be explored for searching life on Mars are those potentially developed underground. Subsurface habitats are currently environments that, under certain physicochemical circumstances, have high thermal and hydrochemical stability [1, 2]. In planets like Mars lacking an atmospheric shield, such systems are obviously protected against radiation, which strongly alters the structure of biological macromolecules. Low porosity but fractured aquifers currently emplaced inside ancient volcano/sedimentary and hydrothermal systems act as excellent habitats [3] due to its thermal and geochemical properties. In these aquifers the temperature is controlled by a thermal balance between conduction and advection processes, which are driven by the rock composition, geological structure, water turnover of aquifers and heat generation from geothermal processes or chemical reactions [4]. Moreover, microbial communities based on chemolithotrophy can obtain energy by the oxidation of metallic ores that are currently associated to these environments. Such a community core may sustain a trophic web composed of non-autotrophic forms like heterotrophic bacteria, fungi and protozoa.

  2. Thermal energy storage – overview and specific insight into nitrate salts for sensible and latent heat storage

    OpenAIRE

    Pfleger, Nicole; Bauer, Thomas; Martin, Claudia; Eck, Markus; Wörner, Antje

    2015-01-01

    Thermal energy storage (TES) is capable to reduce the demand of conventional energy sources for two reasons: First, they prevent the mismatch between the energy supply and the power demand when generating electricity from renewable energy sources. Second, utilization of waste heat in industrial processes by thermal energy storage reduces the final energy consumption. This review focuses mainly on material aspects of alkali nitrate salts. They include thermal properties, thermal decomposition ...

  3. Thermal Energy Storage in Molten Salts: Overview of Novel Concepts and the DLR Test Facility (TESIS)

    OpenAIRE

    Breidenbach, Nils; Martin, Claudia; Jockenhöfer, Henning; Bauer, Thomas

    2016-01-01

    At present, two-tank molten salt storage systems are the established commercially available concept for solar thermal power plants. Due to their very low vapour pressure and comparatively high thermal stability, molten salts are preferred as the heat transfer fluid and storage medium. Therefore, the development of alternative, more cost-effective concepts is an important step in making thermal energy storage more competitive for industrial processes and solar thermal applications. The pape...

  4. Thermal Bridge Impact on the Heating Demand in a Low-Energy House

    OpenAIRE

    Pelss, M; Blumberga, A; Kamenders, A

    2010-01-01

    Thermal bridges typically occur at the junction of different building components where it is difficult to achieve continuity in the thermal insulation layer. In this paper thermal bridges are investigated in the first one-family low-energy house in Latvia. The proportion of the overall heat loss due to thermal bridging is determined based on the results from a numerical calculation method described in the standard LVS EN ISO 10211 and from the simplified calculation method given in the standa...

  5. Sustainable energy supply to very low-energy buildings by means of Micro-CHP technologies and solar thermal energy

    OpenAIRE

    Sicre, Benoit Ghislain

    2005-01-01

    Description and assessment of technology-related concepts aiming at improving the energy conservation in residential buildings. Explanation of the method and discussion of the whole-year simulation results for SOFC micro-CHP systems and Stirling engines in relation with single-family houses of different thermal insulation standards. Benchmark with conventional energy supply systems. Computation of allowable investment costs Beschreibung und Beurteilung unter technischen, ökonom...

  6. Research and Development for Novel Thermal Energy Storage Systems (TES) for Concentrating Solar Power (CSP)

    Energy Technology Data Exchange (ETDEWEB)

    Faghri, Amir; Bergman, Theodore L; Pitchumani, Ranga

    2013-09-26

    The overall objective was to develop innovative heat transfer devices and methodologies for novel thermal energy storage systems for concentrating solar power generation involving phase change materials (PCMs). Specific objectives included embedding thermosyphons and/or heat pipes (TS/HPs) within appropriate phase change materials to significantly reduce thermal resistances within the thermal energy storage system of a large-scale concentrating solar power plant and, in turn, improve performance of the plant. Experimental, system level and detailed comprehensive modeling approaches were taken to investigate the effect of adding TS/HPs on the performance of latent heat thermal energy storage (LHTES) systems.

  7. Seawater pump study: Ocean Thermal Energy Conversion Program. Final report. [For ocean thermal power plants

    Energy Technology Data Exchange (ETDEWEB)

    Little, T.E.

    1978-01-01

    The pumping power required to move cold seawater and warm seawater through an Ocean Thermal Energy Conversion (OTEC) power plant is a significant portion of the plant power output; therefore, seawater pump performance, sizing, and cost information are very influential inputs into any power plant system design optimizations. The analysis and evaluation of large seawater pumping systems selected specifically for the OTEC application are provided with a view toward judging the impact of pump selection on overall OTEC power plant performance. A self-contained bulb, direct drive, axial flow pump was found to have a distinct advantage in performance and arrangement flexibility. A design of a pump operating at a net total head rise of 3.5 meters and a flow capacity of 100 m/sup 3//s is presented including pump blade geometry (profiles), pump diffuser geometry, and pump/diffuser configuration and performance. Results are presented in terms of the geometric and power requirements of several related pump designs over a range of seawater capacity from 25 m/sup 3//s to 100 m/sup 3//s. Summary analysis and evaluations include pump design weights and cost estimates.

  8. Miscibility gap alloys with inverse microstructures and high thermal conductivity for high energy density thermal storage applications

    International Nuclear Information System (INIS)

    New high energy-density thermal storage materials are proposed which use miscibility gap binary alloy systems to operate through the latent heat of fusion of one component dispersed in a thermodynamically stable matrix. Using trial systems Al–Sn and Fe–Cu, we demonstrate the development of the required inverse microstructure (low melting point phase embedded in high melting point matrix) and excellent thermal storage potential. Several other candidate systems are discussed. It is argued that such systems offer enhancement over conventional phase change thermal storage by using high thermal conductivity microstructures (50–400 W/m K); minimum volume of storage systems due to high energy density latent heat of fusion materials (0.2–2.2 MJ/L); and technical utility through adaptability to a great variety of end uses. Low (<300 °C), mid (300–400 °C) and high (600–1400 °C) temperature options exist for applications ranging from space heating and process drying to concentrated solar thermal energy conversion and waste heat recovery. -- Highlights: ► Alloys of immiscible metals are proposed as thermal storage systems. ► High latent heat of fusion per unit volume and tunable temperature are advantageous. ► Thermal storage systems with capacities of 0.2–2.2 MJ/L are identified. ► Heat delivery is via a rigid non-reactive high thermal conductivity matrix. ► The required inverse microstructures were developed for Sn–Al and Cu–Fe systems

  9. Storage of Solar Energy by Application of Thermally Stratified Phase Change Materials. Experimental Research and Optimization

    OpenAIRE

    Dzikēvičs, M; Žandeckis, A

    2014-01-01

    Main aspect when solar thermal energy storage (TES) is considered is thermal storage capacity in form of sensible heat, latent heat or chemical energy. In case of solar systems, solar TES provide a solution for mismatch between energy supply and energy demand. Higher capacity reduces the size of the system and increases overall efficiency [1]. Water is used in almost every system as working fluid due to characteristics like nontoxicity, abundance, high specific heat and suitability for wide r...

  10. The solar thermal energy in France: evaluation and perspectives of the ''solar plan'' DGEMP-DIDEME

    International Nuclear Information System (INIS)

    The solar thermal energy, transformation of the solar energy in heat, is one of the heat production channel by renewable energies, the most promising and dynamic in france. The ''solar plan'', beginning in 2000 aims to promote the solar thermal energy by the improvement of the materials, the formation of the installers, the decrease of the equipment cost and the implementing of qualified installers. (A.L.B.)

  11. Characterization of polymers and Microencapsulated Phase Change Materials used for Thermal Energy Storage in buildings

    OpenAIRE

    Giró Paloma, Jessica

    2015-01-01

    [eng] The use of renewable heat decreases the consumption of fossil resources, although its usage is intermittent and usually does not match the demand. A proper thermal energy storage system design can eliminate this problem by reducing the consumption of non-renewable resources and improving energy efficiency where used. In buildings, thermal energy storage using phase change materials (PCM) is a useful tool to achieve reduction in energy consumption. These can be incorporated into passive ...

  12. Finding India’s place in the Sun –Prospects for harnessing solar thermal energy

    OpenAIRE

    Sundaram, Vijay; Natarajan, Vasant

    2010-01-01

    In this article, we describe our ongoing efforts in addressing the environment and energy challenges facing the world today. Tapping solar thermal energy seems to be the right choice for a country like India. We look at three solar-thermal technologies in the laboratory — water purification/distillation, Stirling engine, and air-conditioning/refrigeration.

  13. The effect of different transitional spaces on thermal comfort and energy consumption of residential buildings

    NARCIS (Netherlands)

    Taleghani, M.; Tenpierik, M.J.; Van den Dobbelsteen, A.A.J.F.

    2012-01-01

    Purpose- This paper focuses on the effect of courtyards, atria and sunspaces on indoor thermal comfort and energy consumption for heating and cooling. One of the most important purposes is to understand if certain transitional spaces can reduce the energy consumption of and improve thermal comfort i

  14. Efficiency of quantum-utilizing solar energy converters in the absence of intraband thermalization

    Energy Technology Data Exchange (ETDEWEB)

    Ross, R.T.

    1979-11-01

    In some photoelectrical and photochemical devices, energy conversion may occur before thermal equilibrium within the electronic bands of the absorber. A statistical thermodynamic argument shows that such hot-transfer devices cannot have an efficiency greater than that of an ideal device in which thermalization precedes energy conversion.

  15. Assessing District Energy Systems Performance Integrated with Multiple Thermal Energy Storages

    Science.gov (United States)

    Rezaie, Behnaz

    The goal of this study is to examine various energy resources in district energy (DE) systems and then DE system performance development by means of multiple thermal energy storages (TES) application. This study sheds light on areas not yet investigated precisely in detail. Throughout the research, major components of the heat plant, energy suppliers of the DE systems, and TES characteristics are separately examined; integration of various configurations of the multiple TESs in the DE system is then analysed. In the first part of the study, various sources of energy are compared, in a consistent manner, financially and environmentally. The TES performance is then assessed from various aspects. Then, TES(s) and DE systems with several sources of energy are integrated, and are investigated as a heat process centre. The most efficient configurations of the multiple TESs integrated with the DE system are investigated. Some of the findings of this study are applied on an actual DE system. The outcomes of this study provide insight for researchers and engineers who work in this field, as well as policy makers and project managers who are decision-makers. The accomplishments of the study are original developments TESs and DE systems. As an original development the Enviro-Economic Function, to balance the economic and environmental aspects of energy resources technologies in DE systems, is developed; various configurations of multiple TESs, including series, parallel, and general grid, are developed. The developed related functions are discharge temperature and energy of the TES, and energy and exergy efficiencies of the TES. The TES charging and discharging behavior of TES instantaneously is also investigated to obtain the charging temperature, the maximum charging temperature, the charging energy flow, maximum heat flow capacity, the discharging temperature, the minimum charging temperature, the discharging energy flow, the maximum heat flow capacity, and performance

  16. Production of desalinated water using ocean thermal energy

    Science.gov (United States)

    Rabas, T.; Panchal, C.

    This paper describes an Ocean Thermal Energy Conversion (OTEC) desalination plant that consists of a multistage flash evaporator (MSF), a closed-cycle OTEC power plant, and an appropriate seawater system depending if the desalination plant is land based or floating. OTEC desalination plants of this type are preferred because the production of desalinated water far exceeds that obtained from other OTEC plant types employing the same size seawater system. The focus of the paper is on the multistage flash evaporator. The similarities and differences between conventional MSF and OTEC multistage flash evaporators (OTEC-MSF) are first described. Then the details of the OTEC-MSF evaporator design are discussed and preliminary correlations are recommended for the three major elements: the flash chamber, the moisture removal device, and the condenser. Recent advances such as enhanced condenser tubes, condensers of the compact type, and corrugated-plate moisture separators are introduced into the design. Comparisons of the water production capability, evaporator shell volume, and material cost are then presented for state-of-the-art and the new design concepts.

  17. Ocean Thermal Energy Conversion (OTEC) Programmatic Environmental Analysis--Appendices

    Energy Technology Data Exchange (ETDEWEB)

    Authors, Various

    1980-01-01

    The programmatic environmental analysis is an initial assessment of Ocean Thermal Energy Conversion (OTEC) technology considering development, demonstration and commercialization. It is concluded that the OTEC development program should continue because the development, demonstration, and commercialization on a single-plant deployment basis should not present significant environmental impacts. However, several areas within the OTEC program require further investigation in order to assess the potential for environmental impacts from OTEC operation, particularly in large-scale deployments and in defining alternatives to closed-cycle biofouling control: (1) Larger-scale deployments of OTEC clusters or parks require further investigations in order to assess optimal platform siting distances necessary to minimize adverse environmental impacts. (2) The deployment and operation of the preoperational platform (OTEC-1) and future demonstration platforms must be carefully monitored to refine environmental assessment predictions, and to provide design modifications which may mitigate or reduce environmental impacts for larger-scale operations. These platforms will provide a valuable opportunity to fully evaluate the intake and discharge configurations, biofouling control methods, and both short-term and long-term environmental effects associated with platform operations. (3) Successful development of OTEC technology to use the maximal resource capabilities and to minimize environmental effects will require a concerted environmental management program, encompassing many different disciplines and environmental specialties. This volume contains these appendices: Appendix A -- Deployment Scenario; Appendix B -- OTEC Regional Characterization; and Appendix C -- Impact and Related Calculations.

  18. Draft environmental assessment: Ocean Thermal Energy Conversion (OTEC) Pilot Plants

    Energy Technology Data Exchange (ETDEWEB)

    Sullivan, S.M.; Sands, M.D.; Donat, J.R.; Jepsen, P.; Smookler, M.; Villa, J.F.

    1981-02-01

    This Environmental Assessment (EA) has been prepared, in accordance with the National Environmental Policy Act of 1969, for the deployment and operation of a commercial 40-Megawatt (MW) Ocean Thermal Energy Conversion (OTEC) Pilot Plant (hereafter called the Pilot Plant). A description of the proposed action is presented, and a generic environment typical of the candidate Pilot Plant siting regions is described. An assessment of the potential environmental impacts associated with the proposed action is given, and the risk of credible accidents and mitigating measures to reduce these risks are considered. The Federal and State plans and policies the proposed action will encompass are described. Alternatives to the proposed action are presented. Appendix A presents the navigation and environmental information contained in the US Coast Pilot for each of the candidate sites; Appendix B provides a brief description of the methods and calculations used in the EA. It is concluded that environmental disturbances associated with Pilot Plant activities could potentially cause significant environmental impacts; however, the magnitude of these potential impacts cannot presently be assessed, due to insufficient engineering and environmental information. A site- and design-specific OTEC Pilot Plant Environmental Impact Statement (EIS) is required to resolve the potentially significant environmental effects associated with Pilot Plant deployment and operation. (WHK)

  19. Effect of Set-point Variation on Thermal Comfort and Energy Use in a Plus-energy Dwelling

    DEFF Research Database (Denmark)

    Toftum, Jørn; Kazanci, Ongun Berk; Olesen, Bjarne W.

    2016-01-01

    When designing buildings and space conditioning systems, the occupant thermal comfort, health, and productivity are the main criteria to satisfy. However, this should be achieved with the most energy-efficient space conditioning systems (heating, cooling, and ventilation). Control strategy, set...... thermally active building systems (TABS), temperatures are allowed to drift within the comfort zone, while in spaces with air-conditioning, temperatures in a narrower interval typically are aimed at. This behavior of radiant systems provides certain advantages regarding energy use, since the temperatures......-points, and control dead-bands have a direct effect on the thermal environment in and the energy use of a building. The thermal environment in and the energy use of a building are associated with the thermal mass of the building and the control strategy, including set-points and control dead-bands. With...

  20. Integrated photovoltaic-thermal solar energy conversion systems

    Science.gov (United States)

    Samara, G. A.

    1975-01-01

    A combined photovoltaic/thermal collector has been built and is now being tested. Initial tests have concentrated on evaluating the thermal efficiency of the collector before and after the silicon cells are mounted. With likely improvements in bonding between cells and receiver and in the absorptivity of the cells, thermal efficiencies greater than 50% can be expected for the combined receiver operating at 100 C.

  1. A comparison of experimental thermal stratification parameters for an oil/pebble-bed thermal energy storage (TES) system during charging

    International Nuclear Information System (INIS)

    Highlights: → Six experimental thermal stratification parameters are evaluated in a TES system. → Stratification number and temperature difference evaluate stratification adequately. → Exergy efficiency and Reynolds number evaluate stratification qualitatively. → Richardson number and energy efficiency not clearly related with stratification. -- Abstract: Six different experimental thermal stratification evaluation parameters during charging for an oil/pebble-bed TES system are presented. The six parameters are the temperature distribution along the height of the storage tank at different time intervals, the charging energy efficiency, the charging exergy efficiency, the stratification number, the Reynolds number and the Richardson number. These parameters are evaluated under six different experimental charging conditions. Temperature distribution along the height of the storage tank at different time intervals and the stratification number are parameters found to describe thermal stratification quantitatively adequately. On the other-hand, the charging exergy efficiency and the Reynolds number give important information about describing thermal stratification qualitatively and should be used with care. The charging energy efficiency and the Richardson number have no clear relationship with thermal stratification.

  2. Essential oil extraction with concentrating solar thermal energy

    OpenAIRE

    Veynandt, François

    2015-01-01

    Material complementari del cas estudi "Essential oil extraction with concentrating solar thermal energy”, part component del llibre "Case studies for developing globally responsible engineers" Peer Reviewed

  3. Cascaded Use of Geothermal Energy and the Thermal Energy Production with Low Costs at the University of Oradea

    OpenAIRE

    Vancea, Cristian; GORDAN Mircea; POP Florica; BITTENBINDER Maria

    2014-01-01

    The development of heat pump technology has led to new opportunities of approaching issues about geothermalism and in particular the use of low and very low enthalpy geothermal resources. Regarding the use of geothermal energy, a special place have the research aimed to ensure the indoor thermal comfort using this form of energy. There have been made a series of research on the best option to use geothermal energy cascade, accompanied by the heat pump technology in the existing thermal statio...

  4. Early Mesozoic basin aquifers

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This data set represents the extent of the Early Mesozoic basin aquifers in the states of Massachusettes, Connecticut, New York, New Jersey, Pennsylvania, Maryland,...

  5. Lower Cretaceous aquifers

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This data set represents the extent of the Lower Cretaceous aquifers in the states of Montana, Wyoming, South Dakota, Kansas, Nebraska, Iowa, and Minnesota..

  6. Preparation, characterization, and thermal properties of starch microencapsulated fatty acids as phase change materials thermal energy storage applications

    Science.gov (United States)

    Stable starch-oil composites can be prepared from renewable resources by excess steam jet-cooking aqueous slurries of starch and vegetable oils or other hydrophobic materials. Fatty acids such as stearic acid are promising phase change materials (PCMs) for latent heat thermal energy storage applica...

  7. Low temperature desalination using solar collectors augmented by thermal energy storage

    International Nuclear Information System (INIS)

    Highlights: ► A new low temperature desalination process using solar collectors was investigated. ► A thermal energy storage tank (TES) was included for continuous process operation. ► Solar collector area and TES volumes were optimized by theoretical simulations. ► Economic analysis for the entire process was compared with and without TES tank. ► Energy and emission payback periods for the solar collector system were reported. -- Abstract: A low temperature desalination process capable of producing 100 L/d freshwater was designed to utilize solar energy harvested from flat plate solar collectors. Since solar insolation is intermittent, a thermal energy storage system was incorporated to run the desalination process round the clock. The requirements for solar collector area as well as thermal energy storage volume were estimated based on the variations in solar insolation. Results from this theoretical study confirm that thermal energy storage is a useful component of the system for conserving thermal energy to meet the energy demand when direct solar energy resource is not available. Thermodynamic advantages of the low temperature desalination using thermal energy storage, as well as energy and environmental emissions payback period of the system powered by flat plate solar collectors are presented. It has been determined that a solar collector area of 18 m2 with a thermal energy storage volume of 3 m3 is adequate to produce 100 L/d of freshwater round the clock considering fluctuations in the weather conditions. An economic analysis on the desalination system with thermal energy storage is also presented.

  8. Thermal Hyper-Conductivity: radiative energy transport in hyperbolic media

    OpenAIRE

    Liu, J; Narimanov, E.

    2014-01-01

    We develop a theoretical description of radiative thermal conductivity in hyperbolic metamaterials. We demonstrate a dramatic enhancement of the radiative thermal transport due to the super-singularity of the photonic density of states in hyperbolic media, leading to the radiative heat conductivity which can be comparable to the non-radiative contribution.

  9. Ogallala Aquifer Mapping Program

    International Nuclear Information System (INIS)

    A computerized data file has been established which can be used efficiently by the contour-plotting program SURFACE II to produce maps of the Ogallala aquifer in 17 counties of the Texas Panhandle. The data collected have been evaluated and compiled into three sets, from which SURFACE II can generate maps of well control, aquifer thickness, saturated thickness, water level, and the difference between virgin (pre-1942) and recent (1979 to 1981) water levels. 29 figures, 1 table

  10. High temperature thermal energy storage, including a discussion of TES integrated into power plants

    Science.gov (United States)

    Turner, R. H.

    1978-01-01

    Storage temperatures of 260 C and above are considered. Basic considerations concerning energy thermal storage are discussed, taking into account general aspects of thermal energy storage, thermal energy storage integrated into power plants, thermal storage techniques and technical considerations, and economic considerations. A description of system concepts is provided, giving attention to a survey of proposed concepts, storage in unpressurized fluids, water storage in pressurized containers, the use of an underground lined cavern for water storage, a submerged thin insulated steel shell under the ocean containing pressurized water, gas passage through solid blocks, a rock bed with liquid heat transport fluid, hollow steel ingots, heat storage in concrete or sand, sand in a fluidized bed, sand poured over pipes, a thermal energy storage heat exchanger, pipes or spheres filled with phase change materials (PCM), macroencapsulated PCM with heat pipe concept for transport fluid, solid PCM removed from heat transfer pipes by moving scrapers, and the direct contact between PCM and transport fluid.

  11. Self-Charged Graphene Battery Harvests Electricity from Thermal Energy of the Environment

    OpenAIRE

    Xu, Zihan; Tai, Guoan; Zhou, Yungang; Gao, Fei; Wong, Kin Hung

    2012-01-01

    The energy of ionic thermal motion presents universally, which is as high as 4 kJ\\bullet kg-1\\bullet K-1 in aqueous solution, where thermal velocity of ions is in the order of hundreds of meters per second at room temperature1,2. Moreover, the thermal velocity of ions can be maintained by the external environment, which means it is unlimited. However, little study has been reported on converting the ionic thermal energy into electricity. Here we present a graphene device with asymmetric elect...

  12. Influence of the thermal neutron energy distribution on results of pulsed measurements with small samples

    International Nuclear Information System (INIS)

    An approach to the problem of the influence of the thermal neutron energy distribution on results of pulsed measurements from the point of view of bounded, small, two-region systems is presented. A model including the energy effects into the description of the decaying thermal neutron flux in bounded two-region systems is proposed. The consequences of neglecting the influence of the energy distribution are also shown. (author)

  13. Charging-free electrochemical system for harvesting low-grade thermal energy

    OpenAIRE

    Yang, Yuan; Lee, Seok Woo; Ghasemi, Hadi; Loomis, James; Li, Xiaobo; Kraemer, Daniel; Zheng, Guangyuan; Cui, Yi; Chen, Gang

    2014-01-01

    Tremendous low-grade heat is stored in industrial processes and the environment. Efficient and low-cost utilization of the low-grade heat is critical to imminent energy and environmental challenges. Here, a rechargeable electrochemical cell (battery) is used to harvest such thermal energy because its voltage changes significantly with temperature. Moreover, by carefully tuning the composition of electrodes, the charging process is purely powered by thermal energy and no electricity is require...

  14. Loss of Shallow Geothermal Resources in Urban Environment Due to the Absence of Thermal Management Policies

    Science.gov (United States)

    García-Gil, A.; Vázquez-Suñé, E.; Sánchez-Navarro, J. A.

    2014-12-01

    Shallow geothermal energy resources are of interest worldwide for the development of strategies against climate change. The current regulative framework for the sustainable implementation of the technologies exploiting this resources is facing several barriers. In the case of groundwater heat pumps, the thermal interference between exploitations may be endangering their feasibility in urban environments. Uncertainty in prediction of the sustainability of shallow geothermal energy development in urban groundwater bodies stems from the absence of a scientific-based legal regulatory framework which protects stakeholders from thermal interferences between existent exploitations systems. The present work consists of a numerical study aimed at understanding and predicting the thermal interference between groundwater heat pumps where several induced heat plumes in an urban ground water body coalesce, thus generating a heat island effect. A transient groundwater flow and heat transport model was developed to reproduce complex high-resolution data obtained from local monitoring specifically designed to control the aquifer respond to geothermal exploitation. The model aims to reproduce the groundwater flow and heat transport processes in a shallow alluvial aquifer exploited by 27 groundwater heat pumps and influenced by a river-aquifer relationship dominated by flood events mainly occurring in winter when the surface temperature is between 3 and 10 ºC. The results from the simulations have quantified the time-space thermal interference between exploitation systems and the consequences of river-aquifer thermal exchange. The results obtained showed the complexity of thermal management of the aquifer due to the transient activity of exploitations over space and time. With the actual exploitation regime of shallow geothermal resources in the investigated area the model predicts a temperature rising tendency in the production wells until 2019 which can compromise the coefficient

  15. Economic Dispatch for Power System Included Wind and Solar Thermal Energy

    OpenAIRE

    Saoussen BRINI; Hsan Hadj ABDALLAH; Ouali, Abderrazak

    2009-01-01

    With the fast development of technologies of alternative energy, the electric power network can be composed of several renewable energy resources. The energy resources have various characteristics in terms of operational costs and reliability. In this study, the problem is the Economic Environmental Dispatching (EED) of hybrid power system including wind and solar thermal energies. Renewable energy resources depend on the data of the climate such as the wind speed for wind energy, solar radia...

  16. A hybrid solar and chemical looping combustion system for solar thermal energy storage

    International Nuclear Information System (INIS)

    Highlights: ► A novel solar–CLC hybrid system is proposed which integrates a CLC with solar thermal energy. ► The oxygen carrier particles are used as storage medium for thermal energy storage. ► A solar cavity reactor is proposed for fuel reactor. ► The absorbed solar energy is stored in the particles to produce a base heat load. -- Abstract: A novel hybrid of a solar thermal energy and a chemical looping combustion (CLC) system is proposed here, which employs the oxygen carrier particles in a CLC system to provide diurnal thermal energy storage for concentrated solar thermal energy. In taking advantage of the chemical and sensible energy storage systems that are an inherent part of a CLC system, this hybrid offers potential to achieve cost effective, base load power generation for solar energy. In the proposed system, three reservoirs have been added to a conventional CLC system to allow storage of the oxygen carrier particles, while a cavity solar receiver has been chosen for the fuel reactor. The performance of the system is evaluated using ASPEN PLUS software, with the model being validated using independent simulation result reported previously. Operating temperature, solar efficiency, solar fraction, exergy efficiency and the fraction of the solar thermal energy stored for a based load power generation application are reported.

  17. Evaluation of thermal response and performance of PHC energy pile: Field experiments and numerical simulation

    International Nuclear Information System (INIS)

    Highlights: ► We performed TRTs for PHC energy piles with 3U- and W- shaped heat exchangers. ► We successfully predicted the monitored thermal behaviors in TRTs by 3D FE analyses. ► We evaluated thermal resistances of energy piles from TRT simulations. ► Thermal performance of the PHC energy pile in Korea was estimated to be efficient. ► Longer pipe was estimated to be beneficial not for base load but for peak load. -- Abstract: This paper presents an experimental and numerical study on evaluation of thermal response and performance of prototype precast-high strength concrete (PHC) energy pile. Short-term field thermal response tests (TRTs) were conducted for the PHC energy piles installed in partially saturated weathered granite soil deposit, in which two types of heat exchangers were considered: W and 3U-shaped heat exchangers. The TRTs were successfully simulated by three-dimensional finite element analyses employing quasi-steady-state convective heat transfer boundary condition. The numerical model was applied to simulate 3-day TRTs, and the simulation results were used for assessing effective thermal conductivity and thermal resistance. Besides, continuous and intermittent operation simulations of the energy piles were performed, and for the results of performance analyses, discussion was made to evaluate energy efficiency of the prototype PHC piles.

  18. Overview of direct air free cooling and thermal energy storage potential energy savings in data centres

    International Nuclear Information System (INIS)

    In the last years the total energy demand of data centres has experienced a dramatic increase which is expected to continue. This is why data centres industry and researchers are working on implementing energy efficiency measures and integrating renewable energy to overcome energy dependence and to reduce operational costs and CO2 emissions. The cooling system of these unique infrastructures can account for 40% of the total energy consumption. To reduce the energy consumption, free cooling strategies are used more and more, but so far there has been little research about the potential of thermal energy storage (TES) solutions to match energy demand and energy availability. Hence, this work intends to provide an overview of the potential of the integration of direct air free cooling strategy and TES systems into data centres located at different European locations. For each location, the benefit of using direct air free cooling is evaluated energetically and economically for a data centre of 1250 kW. The use of direct air free cooling is shown to be feasible. This does not apply the TES systems by itself. But when using TES in combination with an off-peak electricity tariff the operational cooling cost can be drastically reduced. - Highlights: • The total annual hours for direct air free cooling in data centres are calculated. • The potential of TES integration in data centres is evaluated. • The implementation of TES to store the ambient air cold is not recommended. • TES is feasible if combined with redundant chillers and off-peak electricity price. • The cooling electricity cost is being reduced up to 51%, depending on the location

  19. Predictive control and thermal energy storage for optimizing a multi-energy district boiler

    OpenAIRE

    Eynard, Julien; Grieu, Stéphane; Polit, Monique

    2012-01-01

    As part of the OptiEnR research project, the present paper deals with optimizing the multi-energy district boiler of La Rochelle (France) adding to the plant a controlled thermal storage tank. This plant supplies domestic hot water and heats residential and public buildings, using renewable and fossil resources. Due to the complexity of the district boiler as a whole and the strong interactions between the sub-systems, previous works focused first on a modular approach used for the modeling o...

  20. User's manual for computer code SOLTES-1 (simulator of large thermal energy systems)

    International Nuclear Information System (INIS)

    SOLTES simulates the steady-state response of thermal energy systems to time-varying data such as weather and loads. Thermal energy system models of both simple and complex systems can easily be modularly constructed from a library of routines. These routines mathematically model solar collectors, pumps, switches, thermal energy storage, thermal boilers, auxiliary boilers, heat exchangers, extraction turbines, extraction turbine/generators, condensers, regenerative heaters, air conditioners, heating and cooling of buildings, process vapor, etc.; SOLTES also allows user-supplied routines. The analyst need only specify fluid names to obtain readout of property data for heat-transfer fluids and constants that characterize power-cycle working fluids from a fluid property data bank. A load management capability allows SOLTES to simulate total energy systems that simultaneously follow heat and power loads and demands. Generalized energy accounting is available, and values for system performance parameters may be automatically determined by SOLTES. Because of its modularity and flexibility, SOLTES can be used to simulate a wide variety of thermal energy systems such as solar power/total energy, fossil fuel power plants/total energy, nuclear power plants/total energy, solar energy heating and cooling, geothermal energy, and solar hot water heaters

  1. Wind Energy to Thermal and Cold Storage – A Systems Approach

    DEFF Research Database (Denmark)

    Xydis, George

    2013-01-01

    In this paper wind energy to thermal and cold storage scenarios were examined to enable high wind integration through converting renewable electricity excess into thermal or cooling energy, saving part of the energy used in an area and eliminating the need to possibly build a new coal fired plant....... Case studies in Crete Island (not interconnected to the power grid of Greek mainland) with onshore wind power installed were investigated. The aim of this work was to review the options for greater integration of renewables into the grid and the main idea was to analyze the wind to thermal and to cold...

  2. Modeling void growth and movement with phase change in thermal energy storage canisters

    Science.gov (United States)

    Darling, Douglas; Namkoong, David; Skarda, J. R. L.

    1993-01-01

    A scheme was developed to model the thermal hydrodynamic behavior of thermal energy storage salts. The model included buoyancy, surface tension, viscosity, phases change with density difference, and void growth and movement. The energy, momentum, and continuity equations were solved using a finite volume formulation. The momentum equation was divided into two pieces. The void growth and void movement are modeled between the two pieces of the momentum equations. Results showed this scheme was able to predict the behavior of thermal energy storage salts.

  3. Methane-steam reforming by molten salt - membrane reactor using concentrated solar thermal energy

    International Nuclear Information System (INIS)

    By utilization of concentrated solar thermal energy for steam reforming of natural gas, which is an endothermic reaction, the chemical energy of natural gas can be up-graded. The chemical system for steam reforming of natural gas with concentrated solar thermal energy was studied to produce hydrogen by using the thermal storage with molten salt and the membrane reactor. The original steam reforming module with hydrogen permeable palladium membrane was developed and fabricated. Steam reforming of methane proceeded with the original module with palladium membrane below the decomposition temperature of molten salt (around 870 K). (authors)

  4. Joint energy demand and thermal comfort optimization in photovoltaic-equipped interconnected microgrids

    International Nuclear Information System (INIS)

    Highlights: • Energy efficient operation of photovoltaic-equipped interconnected microgrids. • Optimized energy demand for a block of heterogeneous buildings with different sizes. • Multiobjective optimization: matching demand and supply taking into account thermal comfort. • Intelligent control mechanism for heating, ventilating, and air conditioning units. • Optimization of energy consumption and thermal comfort at the aggregate microgrid level. - Abstract: Electrical smart microgrids equipped with small-scale renewable-energy generation systems are emerging progressively as an alternative or an enhancement to the central electrical grid: due to the intermittent nature of the renewable energy sources, appropriate algorithms are required to integrate these two typologies of grids and, in particular, to perform efficiently dynamic energy demand and distributed generation management, while guaranteeing satisfactory thermal comfort for the occupants. This paper presents a novel control algorithm for joint energy demand and thermal comfort optimization in photovoltaic-equipped interconnected microgrids. Energy demand shaping is achieved via an intelligent control mechanism for heating, ventilating, and air conditioning units. The intelligent control mechanism takes into account the available solar energy, the building dynamics and the thermal comfort of the buildings’ occupants. The control design is accomplished in a simulation-based fashion using an energy simulation model, developed in EnergyPlus, of an interconnected microgrid. Rather than focusing only on how each building behaves individually, the optimization algorithm employs a central controller that allows interaction among the buildings of the microgrid. The control objective is to optimize the aggregate microgrid performance. Simulation results demonstrate that the optimization algorithm efficiently integrates the microgrid with the photovoltaic system that provides free electric energy: in

  5. Improvement of energy performances of existing buildings by application of solar thermal systems

    OpenAIRE

    Krstić-Furundžić Aleksandra; Kosorić Vesna

    2009-01-01

    Improvement of energy performances of the existing buildings in the suburban settlement Konjarnik in Belgrade, by the application of solar thermal systems is the topic presented in this paper. Hypothetical models of building improvements are created to allow the benefits of applying solar thermal collectors to residential buildings in Belgrade climate conditions to be estimated. This case study presents different design variants of solar thermal collectors integrated into a multifamily ...

  6. On the transition from photoluminescence to thermal emission and its implication on solar energy conversion

    OpenAIRE

    Manor, Assaf; Martin, Leopoldo L.; Rotschild, Carmel

    2014-01-01

    Photoluminescence (PL) is a fundamental light-matter interaction, which conventionally involves the absorption of energetic photon, thermalization and the emission of a red-shifted photon. Conversely, in optical-refrigeration the absorption of low energy photon is followed by endothermic-PL of energetic photon. Both aspects were mainly studied where thermal population is far weaker than photonic excitation, obscuring the generalization of PL and thermal emissions. Here we experimentally study...

  7. Review On Heat Transfer Enhancement Techniques in Thermal Energy Storage Systems

    Directory of Open Access Journals (Sweden)

    B. Kanimozhi

    2014-02-01

    Full Text Available Heat transfer enhancements of both experimental and analytical studies have been reported in view of their industrial and domestic significances. This review is confined to the enhancement of heat transfer in solidification processes and latent heat thermal storage system due to low heat thermal conductivity of the PCM. The review covers different methods of heat transfer enhancement techniques, encapsulation of phase change materials in Thermal Energy Storage System and solar system.

  8. Review On Heat Transfer Enhancement Techniques in Thermal Energy Storage Systems

    OpenAIRE

    B. Kanimozhi; Prabhu, A

    2014-01-01

    Heat transfer enhancements of both experimental and analytical studies have been reported in view of their industrial and domestic significances. This review is confined to the enhancement of heat transfer in solidification processes and latent heat thermal storage system due to low heat thermal conductivity of the PCM. The review covers different methods of heat transfer enhancement techniques, encapsulation of phase change materials in Thermal Energy Storage System and solar...

  9. LATENT HEAT STORAGE SYSTEM FOR SOLAR THERMAL ENERGY APPLICATIONS

    OpenAIRE

    Raam Dheep. G; Sreekumar. A

    2014-01-01

    The progression of energy supply always possesses some difficulty as the supply does not commensurate with demand. The demand for energy remains higher than production which always leads to imprudent exploitation of precious natural resources, which is available in limited quantities on the mother earth. Energy from non-renewable resources leads to dwindling of natural sources and global warming, whereas energy from renewable resources is sporadic. Solar energy is the primary energy source in...

  10. The potential estimation and factor analysis of China′s energy conservation on thermal power industry

    International Nuclear Information System (INIS)

    At present, researches about energy conservation are focused on prediction. But there are few researches focused on the estimation of effective input and energy conservation potential, and there has been even no research on energy conservation of thermal power industry of China. This paper will try to fill in such a blank. Panel data on Chinese thermal power industry over 2005–2010 are established, and we adopt the stochastic frontier analysis approach to estimate the energy saving potential of thermal power industry. The results are as follows: (1) the average efficiency of energy inputs in China′s thermal power industry over 2005–2010 was about 0.85, and cumulative energy saving potential equals to 551.04 (Mtce); (2) by improving the non-efficiency factors, the relatively backward inland cities could achieve higher energy saving in thermal power industry; (3) the energy input efficiency of Eastern China Grid is shown to be the highest; (4) in order to realize the energy-saving goal of thermal power industry, one important policy method the government should adopt is to conduct a market-oriented reform in power industry and break the state-owned monopoly to provide incentives for private and foreign direct investment in thermal power sector. -- Highlights: •We adopt SFA model to estimate the coal input efficiency of power sector in China. •We calculate the cumulative energy saving potential equals to 551.04 Mtce. •East China power grid has the highest energy input efficiency. •Some backward inland cities may be the main force for future energy conservation. •Encourage private and foreign direct investment in power sector might be effective

  11. Improvement of energy performances of existing buildings by application of solar thermal systems

    Directory of Open Access Journals (Sweden)

    Krstić-Furundžić Aleksandra

    2009-01-01

    Full Text Available Improvement of energy performances of the existing buildings in the suburban settlement Konjarnik in Belgrade, by the application of solar thermal systems is the topic presented in this paper. Hypothetical models of building improvements are created to allow the benefits of applying solar thermal collectors to residential buildings in Belgrade climate conditions to be estimated. This case study presents different design variants of solar thermal collectors integrated into a multifamily building envelope. The following aspects of solar thermal systems integration are analyzed in the paper: energy, architectural, ecological and economic. The results show that in Belgrade climatic conditions significant energy savings and reduction of CO2 emissions can be obtained with the application of solar thermal collectors.

  12. The Evaluation of Feasibility of Thermal Energy Storage System at Riga TPP-2

    Science.gov (United States)

    Ivanova, P.; Linkevics, O.; Cers, A.

    2015-12-01

    The installation of thermal energy storage system (TES) provides the optimisation of energy source, energy security supply, power plant operation and energy production flexibility. The aim of the present research is to evaluate the feasibility of thermal energy system installation at Riga TPP-2. The six modes were investigated: four for non-heating periods and two for heating periods. Different research methods were used: data statistic processing, data analysis, analogy, forecasting, financial method and correlation and regression method. In the end, the best mode was chosen - the increase of cogeneration unit efficiency during the summer.

  13. The Evaluation of Feasibility of Thermal Energy Storage System at Riga TPP-2

    Directory of Open Access Journals (Sweden)

    Ivanova P.

    2015-12-01

    Full Text Available The installation of thermal energy storage system (TES provides the optimisation of energy source, energy security supply, power plant operation and energy production flexibility. The aim of the present research is to evaluate the feasibility of thermal energy system installation at Riga TPP–2. The six modes were investigated: four for non-heating periods and two for heating periods. Different research methods were used: data statistic processing, data analysis, analogy, forecasting, financial method and correlation and regression method. In the end, the best mode was chosen – the increase of cogeneration unit efficiency during the summer.

  14. Conceptual design and engineering studies of adiabatic compressed air energy storage (CAES) with thermal energy storage

    Energy Technology Data Exchange (ETDEWEB)

    Hobson, M. J.

    1981-11-01

    The objective of this study was to perform a conceptual engineering design and evaluation study and to develop a design for an adiabatic CAES system using water-compensated hard rock caverns for compressed air storage. The conceptual plant design was to feature underground containment for thermal energy storage and water-compensated hard rock caverns for high pressure air storage. Other design constraints included the selection of turbomachinery designs that would require little development and would therefore be available for near-term plant construction and demonstration. The design was to be based upon the DOE/EPRI/PEPCO-funded 231 MW/unit conventional CAES plant design prepared for a site in Maryland. This report summarizes the project, its findings, and the recommendations of the study team; presents the development and optimization of the plant heat cycle and the selection and thermal design of the thermal energy storage system; discusses the selection of turbomachinery and estimated plant performance and operational capability; describes the control system concept; and presents the conceptual design of the adiabatic CAES plant, the cost estimates and economic evaluation, and an assessment of technical and economic feasibility. Particular areas in the plant design requiring further development or investigation are discussed. It is concluded that the adiabatic concept appears to be the most attractive candidate for utility application in the near future. It is operationally viable, economically attractive compared with competing concerns, and will require relatively little development before the construction of a plant can be undertaken. It is estimated that a utility could start the design of a demonstration plant in 2 to 3 years if research regarding TES system design is undertaken in a timely manner. (LCL)

  15. Review of electrochemical energy conversion and storage for ocean thermal and wind energy systems

    Science.gov (United States)

    Landgrebe, A. R.; Donley, S. W.

    A literature review on electrochemical storage techniques related to ocean thermal (OTEC) and wind energy conversion systems (WECS) is presented. Battery use for WECS is foreseen because of siting size, variable capacity, quiet operation, and high efficiency; high cost and the necessity for further input voltage regulation is noted, as are prospects for technology transfer from existing programs for photovoltaic panel battery development. Fuel cells, which can run on hydrogen, ammonia, methanol, naphtha, etc., are encouraging because capacity increases are possible by simple addition of more fuel, and high thermal efficiency. Electrolytic use is seen as a cheap replacement source of electricity for metals refining and brine electrolysis. Systems of energy 'bridges' for OTEC plants, to transmit power to users, are reviewed as redox-flow, lithium-water-air, and aluminum batteries, fuel cells, electrolytic hydrogen, methane, and ammonia production, and the use of OTECs as power sources for floating factories. Directions of future research are indicated, noting that WECS will be in commercial production by 1985, while OTEC is far term, around 2025.

  16. Detailed partial load investigation of a thermal energy storage concept for solar thermal power plants with direct steam generation

    Science.gov (United States)

    Seitz, M.; Hübner, S.; Johnson, M.

    2016-05-01

    Direct steam generation enables the implementation of a higher steam temperature for parabolic trough concentrated solar power plants. This leads to much better cycle efficiencies and lower electricity generating costs. For a flexible and more economic operation of such a power plant, it is necessary to develop thermal energy storage systems for the extension of the production time of the power plant. In the case of steam as the heat transfer fluid, it is important to use a storage material that uses latent heat for the storage process. This leads to a minimum of exergy losses during the storage process. In the case of a concentrating solar power plant, superheated steam is needed during the discharging process. This steam cannot be superheated by the latent heat storage system. Therefore, a sensible molten salt storage system is used for this task. In contrast to the state-of-the-art thermal energy storages within the concentrating solar power area of application, a storage system for a direct steam generation plant consists of a latent and a sensible storage part. Thus far, no partial load behaviors of sensible and latent heat storage systems have been analyzed in detail. In this work, an optimized fin structure was developed in order to minimize the costs of the latent heat storage. A complete system simulation of the power plant process, including the solar field, power block and sensible and latent heat energy storage calculates the interaction between the solar field, the power block and the thermal energy storage system.

  17. Cold water aquifer storage. [air conditioning

    Science.gov (United States)

    Reddell, D. L.; Davison, R. R.; Harris, W. B.

    1980-01-01

    A working prototype system is described in which water is pumped from an aquifer at 70 F in the winter time, chilled to a temperature of less than 50 F, injected into a ground-water aquifer, stored for a period of several months, pumped back to the surface in the summer time. A total of 8.1 million gallons of chilled water at an average temperature of 48 F were injected. This was followed by a storage period of 100 days. The recovery cycle was completed a year later with a total of 8.1 million gallons recovered. Approximately 20 percent of the chill energy was recovered.

  18. Thermal Performance Benchmarking; NREL (National Renewable Energy Laboratory)

    Energy Technology Data Exchange (ETDEWEB)

    Moreno, Gilbert

    2015-06-09

    This project proposes to seek out the SOA power electronics and motor technologies to thermally benchmark their performance. The benchmarking will focus on the thermal aspects of the system. System metrics including the junction-to-coolant thermal resistance and the parasitic power consumption (i.e., coolant flow rates and pressure drop performance) of the heat exchanger will be measured. The type of heat exchanger (i.e., channel flow, brazed, folded-fin) and any enhancement features (i.e., enhanced surfaces) will be identified and evaluated to understand their effect on performance. Additionally, the thermal resistance/conductivity of the power module’s passive stack and motor’s laminations and copper winding bundles will also be measured. The research conducted will allow insight into the various cooling strategies to understand which heat exchangers are most effective in terms of thermal performance and efficiency. Modeling analysis and fluid-flow visualization may also be carried out to better understand the heat transfer and fluid dynamics of the systems.

  19. Survey of strategies of energy conservation in Indian thermal power stations

    International Nuclear Information System (INIS)

    Generally, there are several alternative practical energy conservation approaches for thermal power stations, which is an energy intensive, multi-process and heterogeneous industry. The energy and environmental situation obliges power engineers to seriously rethink the problem of energy conservation. The correct solutions are not obvious. Yet the basis of the problem has to be reconsidered and a new perspective has to be taken to cover the overall energy problems of a power plant

  20. Solar thermal energy for supplemental heat to process tea in Sri Lanka

    Energy Technology Data Exchange (ETDEWEB)

    Ariyaratne, A.R.

    1987-01-01

    In tea processing, the subprocesses of withering and drying require thermal energy for dehydration of tea leaves. At present, the Sri Lankan tea industry depends mostly on imported fossil fuels for its thermal energy needs. The economic pressure has forced the industry to investigate energy alternatives. In this study solar thermal energy, heat recovery from fluidized-bed dryers, and a combination of solar system with heat recovery were analyzed. The /phi/, f-chart general design method was used to design solar systems to match thermal energy needs in tea processing. The analysis was extended to the f-chart economic analysis to select economically optimum systems. On the basis of highest life-cycle savings, flat-plate solar-collector area and storage tank were sized. Results showed that solar thermal systems require a high investment,but can provide 42, 52, and 63% of the energy needs for high, mid and low tea growing regions, respectively. Combination of solar thermal systems with heat recovery from a fluidized-bed dryer decreases the amount of energy required by another 7 to 12% yet requires only a small increase in investment.

  1. Transient thermal behaviour of crumb rubber-modified concrete and implications for thermal response and energy efficiency in buildings

    International Nuclear Information System (INIS)

    Experimental data is presented for the dry and saturated steady state thermo-physical properties, and also the dynamic thermal properties, of 180, 120 and 65 mm target slump mix designs for Plain Rubberised Concrete (PRC) with varying %wt rubber substitution and aggregate replacement types (fine, coarse, and mixed). The composites had significantly lower density and thermal conductivity than plain concrete, and there was an inverse relationship between thermal admittance and (a) mix design target slump, and (b) %wt crumb rubber substitution. The thermal decrement remained almost constant, and yet the associated time lag can be increased significantly. Parametric analysis of the effects of crumb rubber substitution for a heavyweight PassivHaus standard dwelling (in non-mechanical ventilation mode) was conducted using building performance simulation. For a London (warmer) or Glasgow (cooler) climate, PRC can be used at up to 30%wt addition and all replacement types as a substitute for plain concrete without causing any significant difference in Dry Resultant Temperature (DRT) fluctuation, if used in conjunction with passive ventilation for night time cooling. However, for the same material there was a general tendency to increase the number of overheating hours in this construction type due to its greater ability to retain any stored heat energy. - Highlights: ► PRC has significantly lower density and thermal conductivity than plain concrete. ► Inverse relationship between thermal admittance and %wt crumb rubber substitution. ► Thermal decrement almost constant but associated time lag increased significantly. ► Up to 30%wt rubber used without significant difference in DRT fluctuation.

  2. Thermal modelling of borehole heat exchangers and borehole thermal energy stores; Zur thermischen Modellierung von Erdwaermesonden und Erdsonden-Waermespeichern

    Energy Technology Data Exchange (ETDEWEB)

    Bauer, Dan

    2011-07-15

    The thermal use of the underground for heating and cooling applications can be done with borehole heat exchangers. This work deals with the further development of the modelling of thermal transport processes inside and outside the borehole as well as with the application of the further developed models. The combination of high accuracy and short computation time is achieved by the development of three-dimensional thermal resistance and capacity models for borehole heat exchangers. Short transient transport processes can be calculated by the developed model with a considerable higher dynamic and accuracy than with known models from literature. The model is used to evaluate measurement data of a thermal response test by parameter estimation technique with a transient three-dimensional model for the first time. Clear advantages like shortening of the test duration are shown. The developed borehole heat exchanger model is combined with a three-dimensional description of the underground in the Finite-Element-Program FEFLOW. The influence of moving groundwater on borehole heat exchangers and borehole thermal energy stores is then quantified.

  3. Performance Analysis of Thermal Energy System with Linear System Method

    Institute of Scientific and Technical Information of China (English)

    Liping LI; Chunfa ZHANG

    2007-01-01

    The paper addresses the system performance of coal-fired power unit with changed auxiliary system or other local heat disturbance. The idea of state space model is imported and the universal formula for the calculation of system performance output is deduced on the system state equation. Two important vector of system are worked out under linear system assumption and transform. The transfer matrix is the characteristics of system itself and is constant for a similar condition, which greatly facilitates the analysis. The concept of thermal disturbance vector is proposed to construct the thermal disturbance input easily. The method can be helpful for analyzing any thermal disturbance input satisfying the assumption and also for supplementing the correction means of performance test. An example of 600MW power unit is presented to demonstrate its availability.

  4. Heat exchangers and thermal energy storage concepts for the off-gas heat of steelmaking devices

    International Nuclear Information System (INIS)

    The fluctuating thermal emissions of electric arc furnaces require energy storage systems to provide downstream consumers with a continuous amount of thermal energy or electricity. Heat recovery systems based on thermal energy storage are presented. A comparison of different thermal energy storage systems has been performed. For the purpose, suitable heat exchangers for the off-gas heat have been developed. Dynamic process simulations of the heat recovery plants were necessary to check the feasibility of the systems and consider the non-steady-state off-gas emissions of the steelmaking devices. The implementation of a pilot plant into an existing off-gas duct of an electric arc furnace was required to check the real behavior of the heat exchanger and determine suitable materials in view of corrosion issues. The pilot plant is presented in this paper.

  5. Candidate thermal energy storage technologies for solar industrial process heat applications

    Science.gov (United States)

    Furman, E. R.

    1979-01-01

    A number of candidate thermal energy storage system elements were identified as having the potential for the successful application of solar industrial process heat. These elements which include storage media, containment and heat exchange are shown.

  6. Solar thermochemical reactions Ⅱ: Synthesis of 2-aminothiophenes via Gewald reaction induced by solar thermal energy

    Institute of Scientific and Technical Information of China (English)

    Ramadan Ahmed Mekheimer; Mohamed Abdallah Ameen; Kamal Usef Sadek

    2008-01-01

    Green conditions have been developed for the synthesis of substituted 2-aminothiopbenes employing multicomponent reactions of a ketone with active methylene nitrile and elemental sulphur induced by free solar thermal energy.

  7. Design of new molten salt thermal energy storage material for solar thermal power plant

    International Nuclear Information System (INIS)

    Highlights: ► New quaternary reciprocal system (K, Na/NO2, Cl, NO3) is prepared. ► This molten salt has a lower melting point. ► This new salt has excellent thermal stability. ► This salt mixture has a reduced cost. - Abstract: In order to obtain molten salt with lower melting point, higher thermal stability and reduced cost relative to previously available materials, a variety of molten salt mixtures of alkali nitrates are investigated by experimental methods. However, since measurements are generally expensive and time-consuming, it is of interest to be able to predict melting point and the component of multi-component systems by using the numerical methods. In this paper, eutectic point and component of a new kind of the quaternary reciprocal system (K, Na/NO2, Cl, NO3) are determined firstly by conformal ionic solution theory. Then thermal stability of the mixtures that show a lower melting point is measured by thermogravimetric analysis device. Experimental results show the agreement between measurements and calculations is found to be very good. This kind of molten salt has a lower melting point, 140 °C. It is thermally stable at temperatures up to 500 °C, and may be used up to 550 °C for short periods. Besides, this molten salt has a reduced cost relative to previous low-melting nitrate mixtures due to the elimination of cesium nitrate and lithium nitrate

  8. Specific yield, High Plains aquifer

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This raster data set represents specific-yield ranges in the High Plains aquifer of the United States. The High Plains aquifer underlies 112.6 million acres...

  9. Thermal emissions and climate change: Cooler options for future energy technology

    OpenAIRE

    Cowern, Nick E. B.; Ahn, Chihak

    2008-01-01

    Global warming arises from 'temperature forcing', a net imbalance between energy fluxes entering and leaving the climate system and arising within it. Humanity introduces temperature forcing through greenhouse gas emissions, agriculture, and thermal emissions from fuel burning. Up to now climate projections, neglecting thermal emissions, typically foresee maximum forcing around the year 2050, followed by a decline. In this paper we show that, if humanity's energy use grows at 1%/year, slower ...

  10. Potential Impact of Biofield Energy Treatment on the Atomic, Physical and Thermal Properties Indium Powder

    OpenAIRE

    Trivedi, Mahendra Kumar

    2015-01-01

    Indium has gained significant attention in the semiconductor industries due to its unique thermal and optical properties. The objective of this research was to investigate the influence of the biofield energy treatment on the atomic, physical and thermal properties of the indium. The study was performed in two groups (control and treated). The control group remained as untreated, and treated group received Mr. Trivedi’s biofield energy treatment. Subsequently, the control and treated in...

  11. Applications of thermal energy storage to waste heat recovery in the food processing industry

    Science.gov (United States)

    Wojnar, F.; Lunberg, W. L.

    1980-01-01

    A study to assess the potential for waste heat recovery in the food industry and to evaluate prospective waste heat recovery system concepts employing thermal energy storage was conducted. The study found that the recovery of waste heat in canning facilities can be performed in significant quantities using systems involving thermal energy storage that are both practical and economical. A demonstration project is proposed to determine actual waste heat recovery costs and benefits and to encourage system implementation by the food industry.

  12. Performance characteristics of a thermal energy storage module - A transient PCM/forced convection conjugate analysis

    Science.gov (United States)

    Cao, Y.; Faghri, A.

    1991-01-01

    The performance of a thermal energy storage module is simulated numerically. The change of phase of the phase-change material (PCM) and the transient forced convective heat transfer for the transfer fluid with low Prandtl numbers are solved simultaneously as a conjugate problem. A parametric study and a system optimization are conducted. The numerical results show that module geometry is crucial to the design of a space-based thermal energy storage system.

  13. The Role of Thermal Storage and Natural Gas in a Smart Energy System

    OpenAIRE

    Jeroen Vandewalle; Nico Keyaerts; William D'haeseleer

    2012-01-01

    Smart grids are considered important building blocks of a future energy system that facilitates integration of massive distributed energy resources like gas-fired cogeneration (CHP). The latter produces thermal and electric power together and as such reinforces the interaction between the gas and electricity-distribution systems. Thermal storage makes up the key-source of flexibility that allows decoupling the electricity production from the heat demand. However, smart grids focus on electric...

  14. Preparation and characterization of phase change material for thermal energy storage in buildings

    Science.gov (United States)

    Lo, Tommy Y.

    2016-04-01

    The paper presents the developing of novel form-stable composite phase change material (PCM) by incorporation of paraffin into lightweight aggregate through vacuum impregnation. The macro-encapsulated Paraffin-lightweight aggregate is a chemical compatible, thermal stable and thermal reliable PCM material for thermal energy storage applications in buildings. The 28 days compressive strength of NWAC using PCM-LWA is 33 - 53 MPa, which has an opportunity for structural purpose. Scanning electronic microscopic images indicated the paraffin can be held inside the porous structure of the aggregate. Thermal performance test showed that the cement paste panel with composite PCM can reduce the indoor temperature.

  15. A thermally regenerative ammonia-based battery for efficient harvesting of low-grade thermal energy as electrical power

    KAUST Repository

    Zhang, Fang

    2015-01-01

    © 2015 The Royal Society of Chemistry. Thermal energy was shown to be efficiently converted into electrical power in a thermally regenerative ammonia-based battery (TRAB) using copper-based redox couples [Cu(NH3)4 2+/Cu and Cu(ii)/Cu]. Ammonia addition to the anolyte (2 M ammonia in a copper-nitrate electrolyte) of a single TRAB cell produced a maximum power density of 115 ± 1 W m-2 (based on projected area of a single copper mesh electrode), with an energy density of 453 W h m-3 (normalized to the total electrolyte volume, under maximum power production conditions). Adding a second cell doubled both the voltage and maximum power. Increasing the anolyte ammonia concentration to 3 M further improved the maximum power density to 136 ± 3 W m-2. Volatilization of ammonia from the spent anolyte by heating (simulating distillation), and re-addition of this ammonia to the spent catholyte chamber with subsequent operation of this chamber as the anode (to regenerate copper on the other electrode), produced a maximum power density of 60 ± 3 W m-2, with an average discharge energy efficiency of ∼29% (electrical energy captured versus chemical energy in the starting solutions). Power was restored to 126 ± 5 W m-2 through acid addition to the regenerated catholyte to decrease pH and dissolve Cu(OH)2 precipitates, suggesting that an inexpensive acid or a waste acid could be used to improve performance. These results demonstrated that TRABs using ammonia-based electrolytes and inexpensive copper electrodes can provide a practical method for efficient conversion of low-grade thermal energy into electricity.

  16. Heat tracer test in an alluvial aquifer: field experiment and inverse modelling

    OpenAIRE

    Klepikova, Maria; Wildemeersch, Samuel; Jamin, Pierre; Orban, Philippe; Hermans, Thomas; Nguyen, Frédéric; Brouyère, Serge; Dassargues, Alain

    2016-01-01

    Using heat as an active tracer for aquifer characterization is a topic of increasing interest. In this study, we investigate the potential of using heat tracer tests for characterization of a shallow alluvial aquifer. A thermal tracer test was conducted in the alluvial aquifer of the Meuse River, Belgium. The tracing experiment consisted in simultaneously injecting heated water and a dye tracer in a piezometer and monitoring the evolution of groundwater temperature and tracer concentration in...

  17. Heat tracer and solute tests in an alluvial aquifer: field experiment and inverse modelling

    OpenAIRE

    Dassargues, Alain; Klepikova, Maria; Jamin, Pierre; Orban, Philippe; Brouyère, Serge

    2015-01-01

    Using heat as an active tracer in different types of aquifers is a topic of increasing interest. In this study, we investigate the potential interest of using heat tracer tests for characterization of a shallow alluvial aquifer. A thermal tracer test was conducted in the alluvial aquifer of the Meuse River, Belgium. The tracing experiment consisted in simultaneously injecting heated water and a dye tracer in a piezometer and monitoring the evolution of groundwater temperature and tracer conce...

  18. Design of a Protection Thermal Energy Storage Using Phase Change Material Coupled to a Solar Receiver

    Science.gov (United States)

    Verdier, D.; Falcoz, Q.; Ferrière, A.

    2014-12-01

    Thermal Energy Storage (TES) is the key for a stable electricity production in future Concentrated Solar Power (CSP) plants. This work presents a study on the thermal protection of the central receiver of CSP plant using a tower which is subject to considerable thermal stresses in case of cloudy events. The very high temperatures, 800 °C at design point, impose the use of special materials which are able to resist at high temperature and high mechanical constraints and high level of concentrated solar flux. In this paper we investigate a TES coupling a metallic matrix drilled with tubes of Phase Change Material (PCM) in order to store a large amount of thermal energy and release it in a short time. A numerical model is developed to optimize the arrangement of tubes into the TES. Then a methodology is given, based from the need in terms of thermal capacity, in order to help the choice of the geometry.

  19. Preparation and Characterization of Microencapsulated Hexadecane Used for Thermal Energy Storage

    Institute of Scientific and Technical Information of China (English)

    Guang Long ZOU; Zhi Cheng TAN; Xiao Zheng LAN; Li Xian SUN; Tao ZHANG

    2004-01-01

    Polyurea microcapsules about 2.5 μm in diameter containing phase change material for thermal energy storage application were synthesized and characterized by interfacial polycondensation method with toluene-2,4-diisocyanate and ethylenediamine as monomers in an emulsion system. Hexadecane was used as a phase change material and OP, which is nonionic surfactant, and used as an emulsifier. The chemical structure and thermal behavior of the microcapsules were investigated by FTIR and thermal analysis respectively. The results show encapsulated hexadecane has a good potential as a solar energy storage material.

  20. Estimation of Wasted Thermal Energy from Gas Turbine Units in Mosul Power Station

    Directory of Open Access Journals (Sweden)

    Dr. A. R. Al-Habbo

    2012-06-01

    Full Text Available The present study involve a thermal analysis of a gas turbine unit like those which are used in Mosul gas turbine power station in order to estimate the amount of thermal energy is wasted in the exhaust gases. A computer program is developed to investigate the effect of ambient temperature on the performance of the gas turbine unit including the mass flow of air, power output, thermal efficiency, specific fuel consumption, exhaust gas temperature and the amount of wasted thermal energy (Qexh.Results indicate that mass flow of air decreases as the ambient temperature increase; this eventually affected the power out, thermal efficiency and specific fuel consumption. Results show that the power output decrease by 28.5% when the temperature increased from 15 ºC to 45 ºC. However, the temperature of exhaust gases increased by nearly 0.04% as the temperature approach 45 ºC and the thermal energy expelled with exhaust decreased nearly by 0.12%. It also found that the wasted thermal energy nearly twice the produced power output of gas turbine.

  1. Limits on the thermal energy release from radioactive wastes in a mined geologic repository

    International Nuclear Information System (INIS)

    The theraml energy release of nuclear wastes is a major factor in the design of geologic repositories. Thermal limits need to be placed on various aspets of the geologic waste disposal system to avoid or retard the degradation of repository performance because of increased temperatures. The thermal limits in current use today are summarized in this report. These limits are placed in a hierarchial structure of thermal criteria consistent with the failure mechanism they are trying to prevent. The thermal criteria hierarchy is used to evaluate the thermal performance of a sample repository design. The design consists of disassembled BWR spent fuel, aged 10 years, close packed in a carbon steel canister with 15 cm of crushed salt backfill. The medium is bedded salt. The most-restrictive temperature for this design is the spent-fuel centerline temperature limit of 3000C. A sensitivity study on the effects of additional cooling prior to disposal on repository thermal limits and design is performed

  2. On the transition from photoluminescence to thermal emission and its implication on solar energy conversion

    CERN Document Server

    Manor, Assaf; Rotschild, Carmel

    2014-01-01

    Photoluminescence (PL) is a fundamental light-matter interaction, which conventionally involves the absorption of energetic photon, thermalization and the emission of a red-shifted photon. Conversely, in optical-refrigeration the absorption of low energy photon is followed by endothermic-PL of energetic photon. Both aspects were mainly studied where thermal population is far weaker than photonic excitation, obscuring the generalization of PL and thermal emissions. Here we experimentally study endothermic-PL at high temperatures. In accordance with theory, we show how PL photon rate is conserved with temperature increase, while each photon is blue shifted. Further rise in temperature leads to an abrupt transition to thermal emission where the photon rate increases sharply. We also show how endothermic-PL generates orders of magnitude more energetic photons than thermal emission at similar temperatures. Relying on these observations, we propose and theoretically study thermally enhanced PL (TEPL) for highly eff...

  3. Carbon dioxide degassing and thermal energy release in the Monte Amiata volcanic-geothermal area (Italy)

    International Nuclear Information System (INIS)

    The quaternary volcanic complex of Mount Amiata is located in southern Tuscany (Italy) and represents the most recent manifestation of the Tuscan Magmatic Province. The region is characterised by a large thermal anomaly and by the presence of numerous CO2-rich gas emissions and geothermal features, mainly located at the periphery of the volcanic complex. Two geothermal systems are located, at increasing depths, in the carbonate and metamorphic formations beneath the volcanic complex. The shallow volcanic aquifer is separated from the deep geothermal systems by a low permeability unit (Ligurian Unit). A measured CO2 discharge through soils of 1.8 x 109 mol a-1 shows that large amounts of CO2 move from the deep reservoir to the surface. A large range in δ13CTDIC (-21.07 to +3.65) characterises the waters circulating in the aquifers of the region and the mass and isotopic balance of TDIC allows distinguishing a discharge of 0.3 x 109 mol a-1 of deeply sourced CO2 in spring waters. The total natural CO2 discharge (2.1 x 109 mol a-1) is slightly less than minimum CO2 output estimated by an indirect method (2.8 x 109 mol a-1), but present-day release of 5.8 x 109 mol a-1 CO2 from deep geothermal wells may have reduced natural CO2 discharge. The heat transported by groundwater, computed considering the increase in temperature from the infiltration area to the discharge from springs, is of the same order of magnitude, or higher, than the regional conductive heat flow (>200 mW m-2) and reaches extremely high values (up to 2700 mW m-2) in the north-eastern part of the study area. Heat transfer occurs mainly by conductive heating in the volcanic aquifer and by uprising gas and vapor along fault zones and in those areas where low permeability cover is lacking. The comparison of CO2 flux, heat flow and geological setting shows that near surface geology and hydrogeological setting play a central role in determining CO2 degassing and heat transfer patterns.

  4. Development and Demonstration of an Innovative Thermal Energy Storage System for Baseload Power Generation

    Energy Technology Data Exchange (ETDEWEB)

    D. Y. Goswami

    2012-09-04

    The objective of this project is to research and develop a thermal energy storage system (operating range 3000C – 450 0C ) based on encapsulated phase change materials (PCM) that can meet the utility-scale base-load concentrated solar power plant requirements at much lower system costs compared to the existing thermal energy storage (TES) concepts. The major focus of this program is to develop suitable encapsulation methods for existing low-cost phase change materials that would provide a cost effective and reliable solution for thermal energy storage to be integrated in solar thermal power plants. This project proposes a TES system concept that will allow for an increase of the capacity factor of the present CSP technologies to 75% or greater and reduce the cost to less than $20/kWht.

  5. Experimental investigation of performances of microcapsule phase change material for thermal energy storage

    Energy Technology Data Exchange (ETDEWEB)

    Li, H. [Department of Material Science and Engineering, Nanjing University, Nanjing (China); Liu, X.; Wu, S. [Department of Physics, Nanjing University, Nanjing (China); Fang, G.

    2010-02-15

    Performances of microcapsule phase change material (MPCM) for thermal energy storage are investigated. The MPCM for thermal energy storage is prepared by a complex coacervation method with gelatin and acacia as wall materials and paraffin as core material in an emulsion system. A scanning electron microscope (SEM) was used to study the microstructure of the MPCM. In thermal analysis, a differential scanning calorimeter (DSC) was employed to determine the melting temperature, melting latent heat, solidification temperature, and solidification latent heat of the MPCM for thermal energy storage. The SEM micrograph indicates that the MPCM has been successfully synthesized and that the particle size of the MPCM is about 81 {mu}m. The DSC output results show that the melting temperature of the MPCM is 52.05 C, the melting latent heat is 141.03 kJ/kg, the solidification temperature is 59.68 C, and the solidification latent heat is 121.59 kJ/kg. The results prove that the MPCM for thermal energy storage has a larger phase change latent heat and suitable phase change temperature, so it can be considered as an efficient thermal energy storage material for heat utilizing systems. (Abstract Copyright [2010], Wiley Periodicals, Inc.)

  6. Independent Energy's Solar thermal products and services listing

    International Nuclear Information System (INIS)

    This article is a listing of companies offering products and services for the development of solar thermal electric power plants. The listing provides the company name under a heading describing the product or service the company provides. The products and services covered by the listing include developers and owner/operators, manufacturers of equipment, instruments and controls, consulting services, engineering and construction, and financial and legal services

  7. Thermally activated building systems in context of increasing building energy efficiency

    Directory of Open Access Journals (Sweden)

    Stojanović Branislav V.

    2014-01-01

    Full Text Available One of the possible ways to provide heating to the building is to use thermally activated building systems. This type of heating, besides providing significant increase in building energy efficiency, allows using low-temperature heating sources. In this paper, special attention is given to opaque part of the building façade with integrated thermally activated building systems. Due to fact that this type of system strongly depends on temperature of this construction-thermal element and type and thickness of other materials of the façade, influence of these parameters on energy efficiency was analyzed in this paper. Since the simplest and most promising way of using geothermal energy is to use it directly, for our analysis this source of energy was selected. Building energy needs for heating were obtained for real residential multi-family building in Serbia by using EnergyPlus software. The building with all necessary input for simulation was modeled in Google SketchUp with aid of Open Studio Plug-in. Obtained results were compared with measured heating energy consumption. The results show that thermally activated building systems represent good way to increase building energy efficiency and that applying certain temperatures within this element, low-energy house standard can be achieved.

  8. Thermal mass impact on energy performance of a low, medium and heavy mass building in Belgrade

    Directory of Open Access Journals (Sweden)

    Anđelković Bojan V.

    2012-01-01

    Full Text Available Heavy mass materials used in building structures and architecture can significantly affect building energy performance and occupant comfort. The purpose of this study was to investigate if thermal mass can improve the internal environment of a building, resulting in lower energy requirements from the mechanical systems. The study was focused on passive building energy performance and compared annual space heating and cooling energy requirements for an office building in Belgrade with several different applications of thermal mass. A three-dimensional building model was generated to represent a typical office building. Building shape, orientation, glazing to wall ratio, envelope insulation thickness, and indoor design conditions were held constant while location and thickness of building mass (concrete was varied between cases in a series of energy simulations. The results were compared and discussed in terms of the building space heating and cooling energy and demand affected by thermal mass. The simulation results indicated that with addition of thermal mass to the building envelope and structure: 100% of all simulated cases experienced reduced annual space heating energy requirements, 67% of all simulated cases experienced reduced annual space cooling energy requirements, 83% of all simulated cases experienced reduced peak space heating demand and 50% of all simulated cases experienced reduced peak space cooling demand. The study demonstrated that there exists a potential for reducing space heating and cooling energy requirements with heavy mass construction in the analyzed climate region (Belgrade, Serbia.

  9. Feasibility study of a self-remediation system for mine drainage using its thermal energy

    Science.gov (United States)

    Oh, Chamteut; Cheong, Youngwook; Yim, Giljae; Ji, Sangwoo

    2016-04-01

    Mine drainage is defined as the water which is discharged to the ground surface through shafts and/or cracks formed by mining activities. Typically, mine drainage features high concentration of acidity and metals since it passes through the underground. Therefore, for the purpose of protecting the surrounding natural environment, mine drainage should be remediated before being discharged to nature. Mine drainage, due to its nature of being retained underground, shows constant temperature which is independent from the temperature of the atmosphere above ground. This condition allows mine drainage to become a promising renewable energy source since energy can be recovered from water with constant temperature. In this research, a self-remediation system is proposed which remediates the mine drainage through electrochemical reactions powered by the thermal energy of mine drainage. High energy efficiency is able to be achieved by shortening the distance between the energy source and consumption, and therefore, this system has a strong advantage to be actualized. A feasibility study for the system was conducted in this research where the thermal energy of mine drainage over time and depth was calculated as energy supply and the required electrical energy for remediating the mine drainage was measured as energy consumption. While the technology of converting thermal energy directly into electrical energy is yet to be developed, energy balance analysis results showed that the proposed self-remediation system is theoretically possible.

  10. Feasibility Study of Heat Driven Cooling Based Thermal Energy Storage

    OpenAIRE

    Athukorala, Niluka

    2012-01-01

    Human needs are unlimited, but resources are limited to satisfy these needs. Because of this reason, consideration of sustainability in utilization of energy is of immense importance. As an intelligent species, mankind is interested in satisfying their needs sustainably. In this view, use of renewable energy, reduction of energy usage, and reduction/ elimination of use of fossil fuels are of great importance. It can be observed that there is rising demand for space cooling, and it has the hig...

  11. Thermal energy storage – overview and specific insight into nitrate salts for sensible and latent heat storage

    Directory of Open Access Journals (Sweden)

    Nicole Pfleger

    2015-07-01

    Full Text Available Thermal energy storage (TES is capable to reduce the demand of conventional energy sources for two reasons: First, they prevent the mismatch between the energy supply and the power demand when generating electricity from renewable energy sources. Second, utilization of waste heat in industrial processes by thermal energy storage reduces the final energy consumption. This review focuses mainly on material aspects of alkali nitrate salts. They include thermal properties, thermal decomposition processes as well as a new method to develop optimized salt systems.

  12. Thermal energy storage – overview and specific insight into nitrate salts for sensible and latent heat storage

    Science.gov (United States)

    Bauer, Thomas; Martin, Claudia; Eck, Markus; Wörner, Antje

    2015-01-01

    Summary Thermal energy storage (TES) is capable to reduce the demand of conventional energy sources for two reasons: First, they prevent the mismatch between the energy supply and the power demand when generating electricity from renewable energy sources. Second, utilization of waste heat in industrial processes by thermal energy storage reduces the final energy consumption. This review focuses mainly on material aspects of alkali nitrate salts. They include thermal properties, thermal decomposition processes as well as a new method to develop optimized salt systems. PMID:26199853

  13. Economic Dispatch for Power System Included Wind and Solar Thermal Energy

    Directory of Open Access Journals (Sweden)

    Saoussen BRINI

    2009-07-01

    Full Text Available With the fast development of technologies of alternative energy, the electric power network can be composed of several renewable energy resources. The energy resources have various characteristics in terms of operational costs and reliability. In this study, the problem is the Economic Environmental Dispatching (EED of hybrid power system including wind and solar thermal energies. Renewable energy resources depend on the data of the climate such as the wind speed for wind energy, solar radiation and the temperature for solar thermal energy. In this article it proposes a methodology to solve this problem. The resolution takes account of the fuel costs and reducing of the emissions of the polluting gases. The resolution is done by the Strength Pareto Evolutionary Algorithm (SPEA method and the simulations have been made on an IEEE network test (30 nodes, 8 machines and 41 lines.

  14. Peak-load pricing and thermal energy storage

    Energy Technology Data Exchange (ETDEWEB)

    1979-01-01

    Twenty papers were presented at the meeting. A separate abstract was prepared for each of 19 papers. One paper was processed previously for the Energy Data Base (EDB). Fifteen of the papers were processed for inclusion in Energy Abstracts for Policy Analysis (EAPA). (LCL)

  15. Application of solar thermal energy to buildings and industry

    Energy Technology Data Exchange (ETDEWEB)

    Kutscher, C. F.

    1981-05-01

    Flat plate collectors and evacuated tube collectors are described, as are parabolic troughs, Fresnel lenses, and compound parabolic concentrators. Use of solar energy for domestic hot water and for space heating and cooling are discussed. Some useful references and methods of system design and sizing are given. This includes mention of the importance of economic analysis. The suitability of solar energy for industrial use is discussed, and solar ponds, point-focus receivers and central receivers are briefly described. The use of solar energy for process hot water, drying and dehydration, and process steam are examined, industrial process heat field tests by the Department of Energy are discussed, and a solar total energy system in Shenandoah, GA is briefly described. (LEW)

  16. Energy Efficiency through Thermal Energy Storage - Evaluation of the Possibilities for the Swedish Building Stock, Phase 1

    OpenAIRE

    Heier, Johan; Bales, Chris; Martin, Viktoria

    2010-01-01

    As a first step in assessing the potential of thermal energy storage in Swedish buildings, the current situation of the Swedish building stock and different storage methods are discussed in this paper. Overall, many buildings are from the 1960’s or earlier having a relatively high energy demand, creating opportunities for large energy savings. The major means of heating are electricity for detached houses and district heating for multi dwelling houses and premises. Cooling needs are relativel...

  17. Process and Economic Optimisation of a Milk Processing Plant with Solar Thermal Energy

    DEFF Research Database (Denmark)

    Bühler, Fabian; Nguyen, Tuong-Van; Elmegaard, Brian;

    2016-01-01

    This work investigates the integration of solar thermal systems for process energy use. A shift from fossil fuels to renewable energy could be beneficial both from environmental and economic perspectives, after the process itself has been optimised and efficiency measures have been implemented. B...

  18. Free Energy of a Hot Gluon Plasma and hard-thermal-loop Resummation

    OpenAIRE

    Jens O. Andersen

    1999-01-01

    In this talk I briefly discuss the thermodynamics of the quark-gluon plasma The calculation of the free energy of a hot gluon plasma to leading order in hard-thermal-loop perturbation theory is outlined. The HTL free energy is compared with the weak-coupling expansion and lattice results.

  19. Impact energy analysis of HSLA specimens after simulated welding thermal cycle

    Directory of Open Access Journals (Sweden)

    Samarždić, I.

    2008-04-01

    Full Text Available This paper presents impact energy results of specimens made from high strength fine grained steel TStE 420 after thermal cycle simulation. These results are obtained by examining Charpy specimens. Metallographic analysis is performed, hardness is measured and total impact energy is divided into ductile and brittle components.

  20. Impact energy analysis of HSLA specimens after simulated welding thermal cycle

    OpenAIRE

    Samarždić, I.; Aračić, S.; Duđner, M.

    2008-01-01

    This paper presents impact energy results of specimens made from high strength fine grained steel TStE 420 after thermal cycle simulation. These results are obtained by examining Charpy specimens. Metallographic analysis is performed, hardness is measured and total impact energy is divided into ductile and brittle components.

  1. Thermal energy storage technologies for sustainability systems design, assessment and applications

    CERN Document Server

    Kalaiselvam, S

    2014-01-01

    Thermal Energy Storage Technologies for Sustainability is a broad-based overview describing the state-of-the-art in latent, sensible, and thermo-chemical energy storage systems and their applications across industries. Beginning with a discussion of the efficiency and conservation advantages of balancing energy demand with production, the book goes on to describe current state-of-the art technologies. Not stopping with description, the authors also discuss design, modeling, and simulation of representative systems, and end with several case studies of systems in use.Describes how thermal energ

  2. Thermal and structural stability of medium energy target carrier assembly for NOvA at Fermilab

    Energy Technology Data Exchange (ETDEWEB)

    McGee, M.W.; Ader, C.; Anderson, K.; Hylen, J.; Martens, M.; /Fermilab

    2010-05-01

    The NOvA project will upgrade the existing Neutrino at Main Injector (NuMI) project beamline at Fermilab to accommodate beam power of 700 kW. The Medium Energy (ME) graphite target assembly is provided through an accord with the State Research Center of Russia Institute for High Energy Physics (IHEP) at Protvino, Russia. The effects of proton beam energy deposition within beamline components are considered as thermal stability of the target carrier assembly and alignment budget are critical operational issues. Results of finite element thermal and structural analysis involving the target carrier assembly is provided with detail regarding the target's beryllium windows.

  3. Energy subsidies in Argentina lead to inequalities and low thermal efficiency

    International Nuclear Information System (INIS)

    Natural gas is the main energy resource for buildings in Argentina. Since 2002, subsidies have kept the prices of this fuel between 9 and 26 times lower than regular prices in other countries. The lowest prices are the result of climate-related subsidies. In cold areas, heating uses several times more energy than locations in Europe with a similar climate. A potential for consumption reductions of up to 70% suggests a very low building thermal performance. The main barriers to finding a solution are the heavy subsidies and public unawareness. Users, government officials, and construction professionals do not identify the very low thermal efficiency. Energy policies to encourage improvements are proposed. (author)

  4. EVALUATION OF FLAT-PLATE PHOTOVOLTAIC THERMAL HYBRID SYSTEMS FOR SOLAR ENERGY UTILIZATION.

    Energy Technology Data Exchange (ETDEWEB)

    ANDREWS,J.W.

    1981-06-01

    The technical and economic attractiveness of combined photovoltaic/thermal (PV/T) solar energy collectors was evaluated. The study was limited to flat-plate collectors since concentrating photovoltaic collectors require active cooling and thus are inherently PV/T collectors, the only decision being whether to use the thermal energy or to dump it. it was also specified at the outset that reduction in required roof area was not to be used as an argument for combining the collection of thermal and electrical energy into one module. Three tests of economic viability were identified, all of which PV/T must pass if it is to be considered a promising alternative: PV/T must prove to be competitive with photovoltaic-only, thermal-only, and side-by-side photovoltaic-plus-thermal collectors and systems. These three tests were applied to systems using low-temperature (unglazed) collectors and to systems using medium-temperature (glazed) collectors in Los Angeles, New York, and Tampa. For photovoltaics, the 1986 DOE cost goals were assumed to have been realized, and for thermal energy collection two technologies were considered: a current technology based on metal and glass, and a future technology based on thin-film plastics. The study showed that for medium-temperature applications PV/T is not an attractive option in any of the locations studied. For low-temperature applications, PV/T appears to be marginally attractive.

  5. Potential environmental consequences of ocean thermal energy conversion (OTEC) plants. A workshop

    Energy Technology Data Exchange (ETDEWEB)

    Walsh, J.J. (ed.)

    1981-05-01

    The concept of generating electrical power from the temperature difference between surface and deep ocean waters was advanced over a century ago. A pilot plant was constructed in the Caribbean during the 1920's but commercialization did not follow. The US Department of Energy (DOE) earlier planned to construct a single operational 10MWe Ocean Thermal Energy Conversion (OTEC) plant by 1986. However, Public Law P.L.-96-310, the Ocean Thermal Energy Conversion Research, Development and Demonstration Act, and P.L.-96-320, the Ocean Thermal Energy Conversion Act of 1980, now call for acceleration of the development of OTEC plants, with capacities of 100 MWe in 1986, 500 MWe in 1989, and 10,000 MWe by 1999 and provide for licensing and permitting and loan guarantees after the technology has been demonstrated.

  6. Thermal solar energy in Spain. State of the art and objectives

    International Nuclear Information System (INIS)

    According the Kyoto protocol, Spain has to reduce its CO2 emissions at 330 millions of tons (a decrease of 18 % from the level of 2003). From the european commission policy, the energy resources will be of 12 % of renewable energies. In this context, Spain developed an energy policy in favor of the solar energy. This document provides information on: the energy market in Spain, the thermal solar energy operating, the CO2 emissions, the state of the art in the domain in spain, the 2010 objectives, the programs and the assistance, some data on the solar market in comparison with the Europe. (A.L.B.)

  7. Thermal Energy for Space Cooling--Federal Technology Alert

    Energy Technology Data Exchange (ETDEWEB)

    Brown, Daryl R.

    2000-12-31

    Cool storage technology can be used to significantly reduce energy costs by allowing energy-intensive, electrically driven cooling equipment to be predominantly operated during off peak hours when electricity rates are lower. This Federal Technology Alert, which is sponsored by DOE's Federal Energy Management Program (FEMP), describes the basic types of cool storage technologies and cooling system integration options. In addition, it defines the savings potential in the federal sector, presents application advice, and describes the performance experience of specific federal users. The results of a case study of a GSA building using cool storage technology are also provided.

  8. Determining an energy-optimal thermal management strategy for electric driven vehicles

    Energy Technology Data Exchange (ETDEWEB)

    Suchaneck, Andre; Probst, Tobias; Puente Leon, Fernando [Karlsruher Institut fuer Technology (KIT), Karlsruhe (Germany). Inst. of Industrial Information Technology (IIIT)

    2012-11-01

    In electric, hybrid electric and fuel cell vehicles, thermal management may have a significant impact on vehicle range. Therefore, optimal thermal management strategies are required. In this paper a method for determining an energy-optimal control strategy for thermal power generation in electric driven vehicles is presented considering all controlled devices (pumps, valves, fans, and the like) as well as influences like ambient temperature, vehicle speed, motor and battery and cooling cycle temperatures. The method is designed to be generic to increase the thermal management development process speed and to achieve the maximal energy reduction for any electric driven vehicle (e.g., by waste heat utilization). Based on simulations of a prototype electric vehicle with an advanced cooling cycle structure, the potential of the method is shown. (orig.)

  9. On thermalization in gamma-ray burst jets and the peak energies of photospheric spectra

    CERN Document Server

    Vurm, Indrek; Piran, Tsvi

    2012-01-01

    The low energy spectral slopes of the prompt emission of most gamma-ray bursts (GRBs) are difficult to reconcile with radiatively efficient optically thin emission models irrespective of the radiation mechanism. An alternative is to ascribe the radiation around the spectral peak to a thermalization process occurring well inside the Thompson photosphere. This quasi-thermal spectrum can evolve into the observed non-thermal shape by additional energy release at moderate to small Thomson optical depths, which can readily give rise to the hard spectral tail. The position of the spectral peak is determined by the temperature and Lorentz factor of the flow in the termalization zone, where the total number of photons carried by the jet is established. To reach thermalization, dissipation alone is not sufficient and photon generation requires an efficient emission/absorption process in addition to scattering. We perform a systematic study of all relevant photon production mechanisms searching for possible conditions i...

  10. Assessment of monitored energy use and thermal comfort conditions in mosques in hot-humid climates

    Energy Technology Data Exchange (ETDEWEB)

    Al-Homoud, Mohammad S.; Abdou, Adel A.; Budaiwi, Ismail M. [Architectural Engineering Department, KFUPM, Dhahran 31261 (Saudi Arabia)

    2009-06-15

    In harsh climatic regions, buildings require air-conditioning in order to provide an acceptable level of thermal comfort. In many situations buildings are over cooled or the HVAC system is kept running for a much longer time than needed. In some other situations thermal comfort is not achieved due to improper operation practices coupled with poor maintenance and even lack it, and consequently inefficient air-conditioning systems. Mosques represent one type of building that is characterized by their unique intermittent operating schedule determined by prayer times, which vary continuously according to the local solar time. This paper presents the results of a study designed to monitor energy use and thermal comfort conditions of a number of mosques in a hot-humid climate so that both energy efficiency and the quality of thermal comfort conditions especially during occupancy periods in such intermittently operated buildings can be assessed accurately. (author)

  11. Advanced latent heat of fusion thermal energy storage for solar power systems

    Science.gov (United States)

    Phillips, W. M.; Stearns, J. W.

    1985-01-01

    The use of solar thermal power systems coupled with thermal energy storage (TES) is being studied for both terrestrial and space applications. In the case of terrestrial applications, it was found that one or two hours of TES could shift the insolation peak (solar noon) to coincide with user peak loads. The use of a phase change material (PCM) is attractive because of the higher energy storage density which can be achieved. However, the use of PCM has also certain disadvantages which must be addressed. Proof of concept testing was undertaken to evaluate corrosive effects and thermal ratcheting effects in a slurry system. It is concluded that the considered alkali metal/alkali salt slurry approach to TES appears to be very viable, taking into account an elimination of thermal ratcheting in storage systems and the reduction of corrosive effects. The approach appears to be useful for an employment involving temperatures applicable to Brayton or Stirling cycles.

  12. Evaluation of in-situ thermal energy storage for lunar based solar dynamic systems

    Science.gov (United States)

    Crane, Roger A.

    1991-01-01

    A practical lunar based thermal energy storage system, based on locally available materials, could significantly reduce transportation requirements and associated costs of a continuous, solar derived power system. The concept reported here is based on a unique, in-situ approach to thermal energy storage. The proposed design is examined to assess the problems of start-up and the requirements for attainment of stable operation. The design remains, at this stage, partially conceptional in nature, but certain aspects of the design, bearing directly on feasibility, are examined in some detail. Specifically included is an engineering evaluation of the projected thermal performance of this system. Both steady state and start-up power requirements are evaluated and the associated thermal losses are evaluated as a basis for establishing potential system performance.

  13. Technological drivers in data centers and telecom systems: Multiscale thermal, electrical, and energy management

    International Nuclear Information System (INIS)

    Highlights: ► Thermal management approaches reviewed against energy usage of IT industry. ► Challenges of energy efficiency in large-scale electronic systems highlighted. ► Underlying drivers for progress at the business and technology levels identified. ► Thermal, electrical and energy management challenges discussed as drivers. ► Views of IT system operators, manufacturers and integrators represented. - Abstract: We identify technological drivers for tomorrow’s data centers and telecommunications systems, including thermal, electrical and energy management challenges, based on discussions at the 2nd Workshop on Thermal Management in Telecommunication Systems and Data Centers in Santa Clara, California, on April 25–26, 2012. The relevance of thermal management in electronic systems is reviewed against the background of the energy usage of the information technology (IT) industry, encompassing perspectives of different sectors of the industry. The underlying drivers for progress at the business and technology levels are identified. The technological challenges are reviewed in two main categories – immediate needs and future needs. Enabling cooling techniques that are currently under development are also discussed

  14. Templated assembly of photoswitches significantly increases the energy-storage capacity of solar thermal fuels

    Energy Technology Data Exchange (ETDEWEB)

    Kucharski, TJ; Ferralis, N; Kolpak, AM; Zheng, JO; Nocera, DG; Grossman, JC

    2014-04-13

    Large-scale utilization of solar-energy resources will require considerable advances in energy-storage technologies to meet ever-increasing global energy demands. Other than liquid fuels, existing energy-storage materials do not provide the requisite combination of high energy density, high stability, easy handling, transportability and low cost. New hybrid solar thermal fuels, composed of photoswitchable molecules on rigid, low-mass nanostructures, transcend the physical limitations of molecular solar thermal fuels by introducing local sterically constrained environments in which interactions between chromophores can be tuned. We demonstrate this principle of a hybrid solar thermal fuel using azobenzene-functionalized carbon nanotubes. We show that, on composite bundling, the amount of energy stored per azobenzene more than doubles from 58 to 120 kJ mol(-1), and the material also maintains robust cyclability and stability. Our results demonstrate that solar thermal fuels composed of molecule-nanostructure hybrids can exhibit significantly enhanced energy-storage capabilities through the generation of template-enforced steric strain.

  15. Templated assembly of photoswitches significantly increases the energy-storage capacity of solar thermal fuels

    Science.gov (United States)

    Kucharski, Timothy J.; Ferralis, Nicola; Kolpak, Alexie M.; Zheng, Jennie O.; Nocera, Daniel G.; Grossman, Jeffrey C.

    2014-05-01

    Large-scale utilization of solar-energy resources will require considerable advances in energy-storage technologies to meet ever-increasing global energy demands. Other than liquid fuels, existing energy-storage materials do not provide the requisite combination of high energy density, high stability, easy handling, transportability and low cost. New hybrid solar thermal fuels, composed of photoswitchable molecules on rigid, low-mass nanostructures, transcend the physical limitations of molecular solar thermal fuels by introducing local sterically constrained environments in which interactions between chromophores can be tuned. We demonstrate this principle of a hybrid solar thermal fuel using azobenzene-functionalized carbon nanotubes. We show that, on composite bundling, the amount of energy stored per azobenzene more than doubles from 58 to 120 kJ mol-1, and the material also maintains robust cyclability and stability. Our results demonstrate that solar thermal fuels composed of molecule-nanostructure hybrids can exhibit significantly enhanced energy-storage capabilities through the generation of template-enforced steric strain.

  16. Preliminary survey and evaluation of nonaquifer thermal energy storage concepts for seasonal storage

    Energy Technology Data Exchange (ETDEWEB)

    Blahnik, D.E.

    1980-11-01

    Thermal energy storage enables the capture and retention of heat energy (or cold) during one time period for use during another. Seasonal thermal energy storage (STES) involves a period of months between the input and recovery of energy. The purpose of this study was to make a preliminary investigation and evaluation of potential nonaquifer STES systems. Current literature was surveyed to determine the state of the art of thermal energy storage (TES) systems such as hot water pond storage, hot rock storage, cool ice storage, and other more sophisticated concepts which might have potential for future STES programs. The main energy sources for TES principally waste heat, and the main uses of the stored thermal energy, i.e., heating, cooling, and steam generation are described. This report reviews the development of sensible, latent, and thermochemical TES technologies, presents a preliminary evaluation of the TES methods most applicable to seasonal storage uses, outlines preliminary conclusions drawn from the review of current TES literature, and recommends further research based on these conclusions. A bibliography of the nonaquifer STES literature review, and examples of 53 different TES concepts drawn from the literature are provided. (LCL)

  17. Technical challenges and future direction for high-efficiency metal hydride thermal energy storage systems

    Science.gov (United States)

    Ward, Patrick A.; Corgnale, Claudio; Teprovich, Joseph A.; Motyka, Theodore; Hardy, Bruce; Sheppard, Drew; Buckley, Craig; Zidan, Ragaiy

    2016-04-01

    Recently, there has been increasing interest in thermal energy storage (TES) systems for concentrated solar power (CSP) plants, which allow for continuous operation when sunlight is unavailable. Thermochemical energy storage materials have the advantage of much higher energy densities than latent or sensible heat materials. Furthermore, thermochemical energy storage systems based on metal hydrides have been gaining great interest for having the advantage of higher energy densities, better reversibility, and high enthalpies. However, in order to achieve higher efficiencies desired of a thermal storage system by the US Department of Energy, the system is required to operate at temperatures >600 °C. Operation at temperatures >600 °C presents challenges including material selection, hydrogen embrittlement and permeation of containment vessels, appropriate selection of heat transfer fluids, and cost. Herein, the technical difficulties and proposed solutions associated with the use of metal hydrides as TES materials in CSP applications are discussed and evaluated.

  18. Thermodynamic Analysis, Simulation and Optimization on Energy Savings of Ideal Internal Thermally Coupled Distillation Columns

    Institute of Scientific and Technical Information of China (English)

    刘兴高; 马龙华; 钱积新

    2000-01-01

    Internal thermally coupled distillation columns (ITCDIC) are the frontier of distillation energy saving research. In this paper, a novel energy saving model of ideal ITCDIC and a simulation algorithm are presented,upon which a series of comparative studies on energy savings with conventional distillation columns are carried out. Furthermore, we present an optimization model of ideal ITCDIC, which can be used to achieve the maximum energy saving and find the optimal design parameters directly. The binary system of benzene-toluene is adopted for the illustrative example of simulation and optimization. The results show that the maximum energy saving of ITCDIC is 52.25% (compared with energy consumption of conventional distillation under the minimum reflux ratio operation); the optimal design parameters are obtained, where the rectifying section pressure and the feed thermal condition are Pr=0.3006 MPa and q=0.5107 respectively.

  19. Thermally activated building systems in context of increasing building energy efficiency

    OpenAIRE

    Stojanović Branislav V.; Janevski Jelena N.; Mitković Petar B.; Stojanović Milica B.; Ignjatović Marko G.

    2014-01-01

    One of the possible ways to provide heating to the building is to use thermally activated building systems. This type of heating, besides providing significant increase in building energy efficiency, allows using low-temperature heating sources. In this paper, special attention is given to opaque part of the building façade with integrated thermally activated building systems. Due to fact that this type of system strongly depends on temperature of this cons...

  20. Quantification of correlational selection on thermal physiology, thermoregulatory behavior, and energy metabolism in lizards

    OpenAIRE

    Artacho, Paulina; Saravia, Julia; Ferrandière, Béatriz Decencière; Perret, Samuel

    2015-01-01

    Phenotypic selection is widely accepted as the primary cause of adaptive evolution in natural populations, but selection on complex functional properties linking physiology, behavior, and morphology has been rarely quantified. In ec-totherms, correlational selection on thermal physiology, thermoregulatory behavior, and energy metabolism is of special interest because of their potential coadaptation. We quantified phenotypic selection on thermal sensitivity of loco-motor performance (sprint sp...