Sample records for baseboard heating

  1. Initial operation of a solar heating and cooling system in a full-scale solar building test facility

    Knoll, R. H.; Miao, D.; Hamlet, I. L.; Jensen, R. N.


    The Solar Building Test Facility (SBTF) located at Hampton, Virginia became operational in early summer of 1976. This facility is a joint effort by NASA-Lewis and NASA-Langley to advance the technology for heating and cooling of office buildings with solar energy. Its purposes are to (1) test system components which include high-performing collectors, (2) test performance of complete solar heating and cooling system, (3) investigate component interactions and (4) investigate durability, maintenance and reliability of components. The SBTF consists of a 50,000 square foot office building modified to accept solar heated water for operation of an absorption air conditioner and for the baseboard heating system. A 12,666 square foot solar collector field with a 30,000 gallon storage tank provides the solar heated water. A description of the system and the collectors selected is given here, along with the objectives, test approach, expected system performance and some preliminary results.

  2. Technoeconomic analysis of a biomass based district heating system

    This paper discussed a proposed biomass-based district heating system to be built for the Pictou Landing First Nation Community in Nova Scotia. The community centre consists of 6 buildings and a connecting arcade. The methodology used to size and design heating, ventilating and air conditioning (HVAC) systems, as well as biomass district energy systems (DES) were discussed. Annual energy requirements and biomass fuel consumption predictions were presented, along with cost estimates. A comparative assessment of the system with that of a conventional oil fired system was also conducted. It was suggested that the design and analysis methodology could be used for any similar application. The buildings were modelled and simulated using the Hourly Analysis Program (HAP), a detailed 2-in-1 software program which can be used both for HVAC system sizing and building energy consumption estimation. A techno-economics analysis was conducted to justify the viability of the biomass combustion system. Heating load calculations were performed assuming that the thermostat was set constantly at 22 degrees C. Community centre space heating loads due to individual envelope components for 3 different scenarios were summarized, as the design architecture for the buildings was not yet finalized. It was suggested that efforts should be made to ensure air-tightness and insulation levels of the interior arcade glass wall. A hydronic distribution system with baseboard space heating units was selected, comprising of a woodchip boiler, hot water distribution system, convective heating units and control systems. The community has its own logging operation which will provide the wood fuel required by the proposed system. An outline of the annual allowable harvest covered by the Pictou Landing Forestry Management Plan was presented, with details of proposed wood-chippers for the creation of biomass. It was concluded that the woodchip combustion system is economically preferable to the

  3. Monitored performance of residential geothermal heat pumps in central Texas and Southern Michigan

    Sullivan, W.N.


    This report summarizes measured performance of residential geothermal heat pumps (GHP`s) that were installed in family housing units at Ft. Hood, Texas and at Selfridge Air National Guard base in Michigan. These units were built as part of a joint Department of Defense/Department of Energy program to evaluate the energy savings potential of GHP`s installed at military facilities. At the Ft. Hood site, the GHP performance was compared to conventional forced air electric air conditioning and natural gas heating. At Selfridge, the homes under test were originally equipped with electric baseboard heat and no air conditioning. Installation of the GHP systems at both sites was straightforward but more problems and costs were incurred at Selfridge because of the need to install ductwork in the homes. The GHP`s at both sites produced impressive energy savings. These savings approached 40% for most of the homes tested. The low cost of energy on these bases relative to the incremental cost of the GHP conversions precludes rapid payback of the GHP`s from energy savings alone. Estimates based on simple payback (no inflation and no interest on capital) indicated payback times from 15 to 20 years at both sites. These payback times may be reduced by considering the additional savings possible due to reduced maintenance costs. Results are summarized in terms of 15 minute, hourly, monthly, and annual performance parameters. The results indicate that all the systems were working properly but several design shortcomings were identified. Recommendations are made for improvements in future installations at both sites.

  4. District heating

    The papers presented at this meeting dealt with an international comparison of district heating, the Swiss district heating network, political aspects of nuclear district heating, nuclear and non-nuclear sources for district heating. 17 figs., 6 tabs

  5. Heat Waves

    Heat Waves Dangers we face during periods of very high temperatures include: Heat cramps: These are muscular pains and spasms due ... that the body is having trouble with the heat. If a heat wave is predicted or happening… - ...

  6. Heat Stress

    ... Publications and Products Programs Contact NIOSH NIOSH HEAT STRESS Recommend on Facebook Tweet Share Compartir NEW Criteria ... hot environments may be at risk of heat stress. Exposure to extreme heat can result in occupational ...

  7. Heat pumps

    Macmichael, DBA


    A fully revised and extended account of the design, manufacture and use of heat pumps in both industrial and domestic applications. Topics covered include a detailed description of the various heat pump cycles, the components of a heat pump system - drive, compressor, heat exchangers etc., and the more practical considerations to be taken into account in their selection.

  8. Heat pumps

    Brodowicz, Kazimierz; Wyszynski, M L; Wyszynski


    Heat pumps and related technology are in widespread use in industrial processes and installations. This book presents a unified, comprehensive and systematic treatment of the design and operation of both compression and sorption heat pumps. Heat pump thermodynamics, the choice of working fluid and the characteristics of low temperature heat sources and their application to heat pumps are covered in detail.Economic aspects are discussed and the extensive use of the exergy concept in evaluating performance of heat pumps is a unique feature of the book. The thermodynamic and chemical properties o

  9. Heat Pipes


    Heat Pipes were originally developed by NASA and the Los Alamos Scientific Laboratory during the 1960s to dissipate excessive heat build- up in critical areas of spacecraft and maintain even temperatures of satellites. Heat pipes are tubular devices where a working fluid alternately evaporates and condenses, transferring heat from one region of the tube to another. KONA Corporation refined and applied the same technology to solve complex heating requirements of hot runner systems in injection molds. KONA Hot Runner Systems are used throughout the plastics industry for products ranging in size from tiny medical devices to large single cavity automobile bumpers and instrument panels.

  10. Heat management

    The conference was based on the Heat Management Ordinance of December 1991 which requires the establishment of heat use concepts for many plants that are subject to licensing. For an industrial enterprises, a good heat use concept is also an energy concept. The papers and discussions of the conference discussed the practical implementation of the Heat Management Ordinance in industrial enterprises and the consequences for licensing practice. Examples of specific plants were presented. The 16 conference papers are available as separate entries on this database. (orig./HP)

  11. Heat pipes

    Dunn, Peter D


    It is approximately 10 years since the Third Edition of Heat Pipes was published and the text is now established as the standard work on the subject. This new edition has been extensively updated, with revisions to most chapters. The introduction of new working fluids and extended life test data have been taken into account in chapter 3. A number of new types of heat pipes have become popular, and others have proved less effective. This is reflected in the contents of chapter 5. Heat pipes are employed in a wide range of applications, including electronics cooling, diecasting and injection mo

  12. Magnetar heating

    Beloborodov, Andrei M


    We examine four candidate mechanisms that could explain the high surface temperatures of magnetars. (1) Heat flux from the liquid core heated by ambipolar diffusion. It could sustain the observed surface luminosity $L_s\\approx 10^{35}$ erg s$^{-1}$ if core heating offsets neutrino cooling at a temperature $T_{\\rm core}>6\\times 10^8$ K. This scenario is viable if the core magnetic field exceeds $10^{16}$ G, the magnetar has mass $M10^{16}$ G varying on a 100 meter scale could provide $L_s\\approx 10^{35}$ erg s$^{-1}$. (4) Bombardment of the stellar surface by particles accelerated in the magnetosphere. This mechanism produces hot spots on magnetars. Observations of transient magnetars show evidence for external heating.

  13. Heat Rash or Prickly Heat (Miliaria Rubra)

    ... rash and rashes clinical tools newsletter | contact Share | Heat Rash or Prickly Heat (Miliaria Rubra) Information for adults A A A ... bumps can suddenly occur, as seen here. Overview Heat rash (miliaria rubra), also known as prickly heat, ...

  14. Heat exchanger

    A heat exchanger having primary and secondary conduits in heat-exchanging relationship is described comprising: at least one serpentine tube having parallel sections connected by reverse bends, the serpentine tube constituting one of the conduits; a group of open-ended tubes disposed adjacent to the parallel sections, the open-ended tubes constituting the other of the conduits, and forming a continuous mass of contacting tubes extending between and surrounding the serpentine tube sections; and means securing the mass of tubes together to form a predetermined cross-section of the entirety of the mass of open-ended tubes and tube sections

  15. Monopole heat

    Upper bounds on the flux of monopoles incident on the Earth with velocity -5 c(1016 GeV m-1) and on the flux of monopoles incident on Jupiter with velocity -3 c(1016 GeV m-1), are derived. Monopoles moving this slowly lose sufficient energy to be stopped, and then catalyse nucleon decay, releasing heat. The limits are obtained by requiring the rate of energy release from nucleon decay to be less than the measured amount of heat flowing out from the surface of the planet. (U.K.)

  16. Heat transfer

    Holman, J P


    As one of the most popular heat transfer texts, Jack Holman's "Heat Transfer" is noted for its clarity, accessible approach, and inclusion of many examples and problem sets. The new tenth edition retains the straight-forward, to-the-point writing style while covering both analytical and empirical approaches to the subject. Throughout the book, emphasis is placed on physical understanding while, at the same time, relying on meaningful experimental data in those situations that do not permit a simple analytical solution. New examples and templates provide students with updated resources for computer-numerical solutions.

  17. Heat exchanger

    A heat exchanger of the straight tube type is described in which different rates of thermal expansion between the straight tubes and the supply pipes furnishing fluid to those tubes do not result in tube failures. The supply pipes each contain a section which is of helical configuration

  18. Heat-Related Illnesses

    Full Text Available ... for signs of heat stroke or exhaustion. Heat Stroke and Exhaustion Symptoms of early heat exhaustion symptoms ... heavy sweating; nausea; and giddiness. Symptoms of heat stroke (late stage of heat illness) include flushed, hot, ...

  19. Heat Exchanger

    A liquid metal heated tube and shell heat exchanger where straight tubes extend between upper and lower tube sheets. In order to prevent thermal stress problems, one tube sheet is fixed to the shell, and the other tube sheet is sealed to the shell by means of a flexible bellows. In the event of a catastrophic bellows failure, a housing that utilizes a packing gland sliding seal is used to enclose and back-up the bellows. Also, a key and slot arrangement is provided for preventing relative rotation between the shell and tube sheet which could damage the bellows and cause failure thereof. This exchanger is seen to be of use in sodium cooled reactors between the liquid sodium circuit on the steam generator

  20. 'Heat Dome' Heats Up United States

    ... news/fullstory_160028.html 'Heat Dome' Heats Up United States Much of the country to be under ... As a massive "heat dome" stretches across the United States this week, sending temperatures and humidity levels ...

  1. Heating systems for heating subsurface formations

    Nguyen, Scott Vinh (Houston, TX); Vinegar, Harold J. (Bellaire, TX)


    Methods and systems for heating a subsurface formation are described herein. A heating system for a subsurface formation includes a sealed conduit positioned in an opening in the formation and a heat source. The sealed conduit includes a heat transfer fluid. The heat source provides heat to a portion of the sealed conduit to change phase of the heat transfer fluid from a liquid to a vapor. The vapor in the sealed conduit rises in the sealed conduit, condenses to transfer heat to the formation and returns to the conduit portion as a liquid.

  2. Heat transfer

    Jorge, Kubie; Thomas, Grassie


    A core task of engineers is to analyse energy related problems. The analytical treatment is usually based on principles of thermodynamics, fluid mechanics and heat transfer, but is increasingly being handled computationally.This unique resource presents a practical textbook, written for both undergraduates and professionals, with a series of over 60 computer workbooks on an accompanying CD.The book emphasizes how complex problems can be deconstructed into a series of simple steps. All thermophysical property computations are illustrated using diagrams within text and on the compani

  3. Heat pipes

    Dunn, Peter D


    A comprehensive, up-to-date coverage of the theory, design and manufacture of heat pipes and their applications. This latest edition has been thoroughly revised, up-dated and expanded to give an in-depth coverage of the new developments in the field. Significant new material has been added to all the chapters and the applications section has been totally rewritten to ensure that topical and important applications are appropriately emphasised. The bibliography has been considerably enlarged to incorporate much valuable new information. Thus readers of the previous edition, which has established

  4. Radiofrequency plasma heating: proceedings

    The conference proceedings include sessions on Alfven Wave Heating, ICRF Heating and Current Drive, Lower Hybrid Heating and Current Drive, and ECRF Heating. Questions of confinement, diagnostics, instabilities and technology are considered. Individual papers are cataloged separately

  5. Heat-Related Illnesses

    ... Emergencies A-Z Share this! Home » Emergency 101 Heat-Related Illnesses Dr. Glenn Mitchell , Emergency physician at ... about heat cramps and heat stroke and exhaustion. Heat Cramps Symptoms include muscle spasms, usually in the ...

  6. Heat-Related Illnesses

    Full Text Available ... Emergencies A-Z Share this! Home » Emergency 101 Heat-Related Illnesses Dr. Glenn Mitchell , Emergency physician at ... about heat cramps and heat stroke and exhaustion. Heat Cramps Symptoms include muscle spasms, usually in the ...

  7. Low temperature nuclear heat

    Kotakorpi, J.; Tarjanne, R. (comps.)


    The meeting was concerned with the use of low grade nuclear heat for district heating, desalination, process heat, and agriculture and aquaculture. The sessions covered applications and demand, heat sources, and economics.

  8. Segmented heat exchanger

    Baldwin, Darryl Dean; Willi, Martin Leo; Fiveland, Scott Byron; Timmons, Kristine Ann


    A segmented heat exchanger system for transferring heat energy from an exhaust fluid to a working fluid. The heat exchanger system may include a first heat exchanger for receiving incoming working fluid and the exhaust fluid. The working fluid and exhaust fluid may travel through at least a portion of the first heat exchanger in a parallel flow configuration. In addition, the heat exchanger system may include a second heat exchanger for receiving working fluid from the first heat exchanger and exhaust fluid from a third heat exchanger. The working fluid and exhaust fluid may travel through at least a portion of the second heat exchanger in a counter flow configuration. Furthermore, the heat exchanger system may include a third heat exchanger for receiving working fluid from the second heat exchanger and exhaust fluid from the first heat exchanger. The working fluid and exhaust fluid may travel through at least a portion of the third heat exchanger in a parallel flow configuration.

  9. Heat pumps in district heating networks

    Ommen, Torben Schmidt; Markussen, Wiebke Brix; Elmegaard, Brian

    In the current Danish energy system, the majority of electricity and heat is produced in combined heat and power plants. With increasing shares of intermittent renewable power production, it becomes a challenging task to match power and heat production, as heat demand and production capacity...... constraints limit the power plants. Efficient heat pumps can be used to decouple the constraints of electricity and heat production, while maintaining the high energy efficiency needed to match the politically agreed carbon emission goals. The requirements in terms of COP, location, capacity and economy...... and strategic planning in the energy sector. The paper presents a case study of optimal implementation of heat pumps in the present energy system of the Copenhagen area. By introduction of the correct capacity of heat pumps, a 1,6 % reduction in fuel consumption for electricity and heat production can...

  10. Heat pump technology

    Von Cube, Hans Ludwig; Goodall, E G A


    Heat Pump Technology discusses the history, underlying concepts, usage, and advancements in the use of heat pumps. The book covers topics such as the applications and types of heat pumps; thermodynamic principles involved in heat pumps such as internal energy, enthalpy, and exergy; and natural heat sources and energy storage. Also discussed are topics such as the importance of the heat pump in the energy industry; heat pump designs and systems; the development of heat pumps over time; and examples of practical everyday uses of heat pumps. The text is recommended for those who would like to kno

  11. Cryogenic heat transfer

    Barron, Randall F


    Cryogenic Heat Transfer, Second Edition continues to address specific heat transfer problems that occur in the cryogenic temperature range where there are distinct differences from conventional heat transfer problems. This updated version examines the use of computer-aided design in cryogenic engineering and emphasizes commonly used computer programs to address modern cryogenic heat transfer problems. It introduces additional topics in cryogenic heat transfer that include latent heat expressions; lumped-capacity transient heat transfer; thermal stresses; Laplace transform solutions; oscillating flow heat transfer, and computer-aided heat exchanger design. It also includes new examples and homework problems throughout the book, and provides ample references for further study.

  12. Heat Rash or Prickly Heat (Miliaria Rubra)

    ... heat rash consist of controlling heat and humidity. Acetaminophen or ibuprofen can help to reduce fever. Remove ... without any sweat. Your child may complain of dizziness, nausea, weakness, headache, confusion, or difficulty breathing. This ...

  13. Multidimensional Heat Conduction

    Rode, Carsten


    Analytical theory of multidimensional heat conduction. General heat conduction equation in three dimensions. Steay state, analytical solutions. The Laplace equation. Method of separation of variables. Principle of superposition. Shape factors. Transient, multidimensional heat conduction....

  14. Oscillating heat pipes

    Ma, Hongbin


    This book presents the fundamental fluid flow and heat transfer principles occurring in oscillating heat pipes and also provides updated developments and recent innovations in research and applications of heat pipes. Starting with fundamental presentation of heat pipes, the focus is on oscillating motions and its heat transfer enhancement in a two-phase heat transfer system. The book covers thermodynamic analysis, interfacial phenomenon, thin film evaporation,  theoretical models of oscillating motion and heat transfer of single phase and two-phase flows, primary  factors affecting oscillating motions and heat transfer,  neutron imaging study of oscillating motions in an oscillating heat pipes, and nanofluid’s effect on the heat transfer performance in oscillating heat pipes.  The importance of thermally-excited oscillating motion combined with phase change heat transfer to a wide variety of applications is emphasized. This book is an essential resource and learning tool for senior undergraduate, gradua...

  15. Heat Cramps, First Aid

    ... rashes clinical tools newsletter | contact Share | Heat Cramps, First Aid A A A Heat cramp signs and symptoms ... if later stages of heat illness are suspected. First Aid Guide Use a combination of the following measures, ...

  16. Heat Exhaustion, First Aid

    ... rashes clinical tools newsletter | contact Share | Heat Exhaustion, First Aid A A A Heat exhaustion signs and symptoms ... specific to the other stages of heat illness. First Aid Guide Use a combination of the following measures ...

  17. Solar heat storages in district heating networks

    Ellehauge, K. (Ellehauge og Kildemoes, AArhus (DK)); Engberg Pedersen, T. (COWI A/S, Kgs. Lyngby (DK))


    This report gives information on the work carried out and the results obtained in Denmark on storages for large solar heating plants in district heating networks. Especially in Denmark the share of district heating has increased to a large percentage. In 1981 around 33% of all dwellings in DK were connected to a district heating network, while the percentage in 2006 was about 60% (in total 1.5 mio. dwellings). In the report storage types for short term storage and long term storages are described. Short term storages are done as steel tanks and is well established technology widely used in district heating networks. Long term storages are experimental and used in connection with solar heating. A number of solar heating plants have been established with either short term or long term storages showing economy competitive with normal energy sources. Since, in the majority of the Danish district heating networks the heat is produced in co-generation plants, i.e. plants producing both electricity and heat for the network, special attention has been put on the use of solar energy in combination with co-generation. Part of this report describes that in the liberalized electricity market central solar heating plants can also be advantageous in combination with co-generation plants. (au)

  18. Heat Roadmap Europe

    Hansen, Kenneth; Connolly, David; Lund, Henrik;


    The cost of heat savings in buildings increase as more heat savings are achieved due to the state of the building stock and hence, alternatives other than savings typically become more economically feasible at a certain level of heat reductions. It is important to identify when the cost of heat s...

  19. Transient Heat Conduction

    Rode, Carsten


    Analytical theory of transient heat conduction.Fourier's law. General heat conducation equation. Thermal diffusivity. Biot and Fourier numbers. Lumped analysis and time constant. Semi-infinite body: fixed surface temperature, convective heat transfer at the surface, or constant surface heat flux...

  20. The Gravitational Heat Exchanger

    De Aquino, Fran


    The heat exchangers are present in many sectors of the economy. They are widely used in Refrigerators, Air-conditioners, Engines, Refineries, etc. Here we show a heat exchanger that works based on the gravity control. This type of heat exchanger can be much more economic than the conventional heat exchangers.

  1. Nature's Heat Exchangers.

    Barnes, George


    Discusses the heat-transfer systems of different animals. Systems include heat conduction into the ground, heat transferred by convection, heat exchange in lizards, fish and polar animals, the carotid rete system, electromagnetic radiation from animals and people, and plant and animal fiber optics. (MDH)

  2. Heat Pipe Planets

    Moore, William B.; Simon, Justin I.; Webb, A. Alexander G.


    When volcanism dominates heat transport, a terrestrial body enters a heat-pipe mode, in which hot magma moves through the lithosphere in narrow channels. Even at high heat flow, a heat-pipe planet develops a thick, cold, downwards-advecting lithosphere dominated by (ultra-)mafic flows and contractional deformation at the surface. Heat-pipes are an important feature of terrestrial planets at high heat flow, as illustrated by Io. Evidence for their operation early in Earth's history suggests that all terrestrial bodies should experience an episode of heat-pipe cooling early in their histories.

  3. The Heat Is On

    Brian Hill


    Qualification in track and field events involves runners competing against individuals within their heat and runners in other heats. Given that the heats are run sequentially, runners in each heat have different information about their competitors. Using data on track and field events from 2001-2011, this article examines whether an individual’s placement in a specific heat and their peers affect their performance and qualification probability. Results indicate that runners’ times and qua...

  4. [Heat waves: health impacts].

    Marto, Natália


    During the summer of 2003, record high temperatures were reported across Europe, causing thousands of casualties. Heat waves are sporadic recurrent events, characterised by intense and prolonged heat, associated with excess mortality and morbidity. The most frequent cause of death directly attributable to heat is heat stroke but heat waves are known to cause increases in all-cause mortality, specially circulatory and respiratory mortality. Epidemiological studies demonstrate excess casualties cluster in specific risk groups. The elderly, those with chronic medical conditions and the socially isolated are particularly vulnerable. Air conditioning is the strongest protective factor against heat-related disorders. Heat waves cause disease indirectly, by aggravating chronic disorders, and directly, by causing heat-related illnesses (HRI). Classic HRI include skin eruptions, heat cramps, heat syncope, heat exhaustion and heat stroke. Heat stroke is a medical emergency characterised by hyperthermia and central nervous system dysfunction. Treatment includes immediate cooling and support of organ-system function. Despite aggressive treatment, heat stroke is often fatal and permanent neurological damage is frequent in those who survive. Heat related illness and death are preventable through behavioural adaptations, such as use of air conditioning and increased fluid intake. Other adaptation measures include heat emergency warning systems and intervention plans and environmental heat stress reduction. Heat related mortality is expected to rise as a consequence of the increasing proportion of elderly persons, the growing urban population, and the anticipated increase in number and intensity of heat waves associated with global warming. Improvements in surveillance and response capability may limit the adverse health conditions of future heat waves. It is crucial that health professionals are prepared to recognise, prevent and treat HRI and learn to cooperate with local health

  5. Introduction to heat transfer



    Presenting the basic mechanisms for transfer of heat, Introduction to Heat Transfer gives a deeper and more comprehensive view than existing titles on the subject. Derivation and presentation of analytical and empirical methods are provided for calculation of heat transfer rates and temperature fields as well as pressure drop. The book covers thermal conduction, forced and natural laminar and turbulent convective heat transfer, thermal radiation including participating media, condensation, evaporation and heat exchangers.

  6. Open district heating and marginal cost based heat pricing

    Mäkelä, Henri


    Currently, an increasing usage of individual heating systems such as heat pumps and solar heat collectors, pose a challenge to the district heating market. However, individual heating technologies together with industrial processes produce excess heat, which can be utilized in district heating. The usage of excess heat can be seen as an opportuni-ty for new business strategies in district heating. The objective of this thesis was to simulate hourly district heat production in an open dist...

  7. Basic heat transfer

    Bacon, D H


    Basic Heat Transfer aims to help readers use a computer to solve heat transfer problems and to promote greater understanding by changing data values and observing the effects, which are necessary in design and optimization calculations.The book is concerned with applications including insulation and heating in buildings and pipes, temperature distributions in solids for steady state and transient conditions, the determination of surface heat transfer coefficients for convection in various situations, radiation heat transfer in grey body problems, the use of finned surfaces, and simple heat exc

  8. Microscale Regenerative Heat Exchanger

    Moran, Matthew E.; Stelter, Stephan; Stelter, Manfred


    The device described herein is designed primarily for use as a regenerative heat exchanger in a miniature Stirling engine or Stirling-cycle heat pump. A regenerative heat exchanger (sometimes called, simply, a "regenerator" in the Stirling-engine art) is basically a thermal capacitor: Its role in the Stirling cycle is to alternately accept heat from, then deliver heat to, an oscillating flow of a working fluid between compression and expansion volumes, without introducing an excessive pressure drop. These volumes are at different temperatures, and conduction of heat between these volumes is undesirable because it reduces the energy-conversion efficiency of the Stirling cycle.

  9. Plasma heat pump and heat engine

    A model system where cold charged particles are locally confined in a volume VP within a warm plasma of volume V (VPE. The law of thermodynamics involving PE and an equation of state for PE are obtained. It is shown that the expansion/compression of electrostatic fields associated with charged particles is a new mechanism that converts mechanical work into plasma heat and vice versa. Two applications of this theory are, first we propose a pumping device which heats plasmas by an adiabatic/isothermal compression of fields. Heating power ranging from a few hundred watts to a few kilowatts is possible with the present day technology. Second, we discuss the feasibility of constructing an electrostatic heat engine which converts plasma heat into mechanical work via plasma electric fields. Effects of PE are shown to be observable in colloidal solutions.

  10. Heat-Related Illnesses

    Full Text Available ... 911 What To Do In A Medical Emergency Childhood Emergencies Careers in Emergency Medicine Seconds Save Lives ... or exhaustion. Heat Stroke and Exhaustion Symptoms of early heat exhaustion symptoms include cool, moist, pale or ...

  11. Heat-Related Illnesses

    Full Text Available ... for Disasters Communication With Your Family And Your Doctor About Your Wishes Visiting the ER Who Takes ... 101 Heat-Related Illnesses Dr. Glenn Mitchell , Emergency physician at Mercy Health System in Chesterfield, Missouri Heat- ...

  12. Heat Wave Safety Checklist

    ... itself. ❏ Signs of heat stroke include hot, red skin which may be dry or moist; changes in consciousness; vomiting; and high body temperature. ❏ Heat stroke is life-threatening. Call 9-1-1 or ...

  13. Salix to heat glasshouses

    Tremeer, R.


    A wood chip heating plant supplied by short rotation coppice and existing woodland and hedges is used to heat glass houses. The reasons for changing to wood-fuel are developed in the paper. (TEC). 1 fig.

  14. Convective heat transfer

    Kakac, Sadik; Pramuanjaroenkij, Anchasa


    Intended for readers who have taken a basic heat transfer course and have a basic knowledge of thermodynamics, heat transfer, fluid mechanics, and differential equations, Convective Heat Transfer, Third Edition provides an overview of phenomenological convective heat transfer. This book combines applications of engineering with the basic concepts of convection. It offers a clear and balanced presentation of essential topics using both traditional and numerical methods. The text addresses emerging science and technology matters, and highlights biomedical applications and energy technologies. What’s New in the Third Edition: Includes updated chapters and two new chapters on heat transfer in microchannels and heat transfer with nanofluids Expands problem sets and introduces new correlations and solved examples Provides more coverage of numerical/computer methods The third edition details the new research areas of heat transfer in microchannels and the enhancement of convective heat transfer with nanofluids....

  15. Radial heat flux transformer

    Basiulis, A.; Buzzard, R. J.


    Unit moves heat radially from small diameter shell to larger diameter shell, or vice versa, with negligible temperature drop, making device useful wherever heating or cooling of concentrically arranged materials, substances, and structures is desired.

  16. Regenerative heat sources for heating networks

    The ambitious goal, the German Federal Government has set itself, to reduce the emissions of greenhouse gases by 80% to 95% by the year 2050. As there are currently more than half of German energy consumption for the production of heat is required, big contributions to climate protection can be expected from this area if more renewable heat sources are used. Renewable heat sources such as bioenergy, solar thermal and geothermal energy in particular can be provided as compared to fossil fuels with significantly lower specific CO2 emissions. Objectives in the heating market and scenarios for the transformation of the heat sector have been elaborated in the BMU Lead Study 2011. The main pillar of this scenario is the reduction of final energy consumption for heat by the energy-efficient renovation of existing buildings and further increasing demands on the energetic quality of new buildings. To cover the remaining energy demand, a focus is on the expansion of heating networks based on renewable energies.

  17. Heat exchanger design

    Loukota, Martin


    This bachelor thesis solves design of a heat exchanger for hot water boiler with gasification chamber for preheating the combustion air with the heat of the combustion products. Calculation values were experimentally measured. Thesis contains brief description of the shell and tube heat exchanger, stoichiometric combustion calculation, geometrical dimensions design of the heat exchanger, pressure loss and thermal performance calculation. It also includes drawings of the designed exchanger.

  18. Estimation of Heating Device‘s Convective Heat Transfer of Heat Supply Systems with Rotational Heat Generator

    A. Nesenchuk


    Full Text Available In this article, on the base of heat exchange analysis in heat supply systems with rotational heat generator, a calculated formula for estimation of heat transfer from the surface of heating device is obtained, taking into account its probability (random orientation in space. It is shown the most probable position of heating devices in heating system of mobile object.

  19. Estimation of Heating Device‘s Convective Heat Transfer of Heat Supply Systems with Rotational Heat Generator

    A. Nesenchuk; I. Iokova; T. Rizova; P. Lasij; D. Shklovchik; Z. Aidarova


    In this article, on the base of heat exchange analysis in heat supply systems with rotational heat generator, a calculated formula for estimation of heat transfer from the surface of heating device is obtained, taking into account its probability (random) orientation in space. It is shown the most probable position of heating devices in heating system of mobile object.

  20. Liquid heat capacity lasers

    Comaskey, Brian J.; Scheibner, Karl F.; Ault, Earl R.


    The heat capacity laser concept is extended to systems in which the heat capacity lasing media is a liquid. The laser active liquid is circulated from a reservoir (where the bulk of the media and hence waste heat resides) through a channel so configured for both optical pumping of the media for gain and for light amplification from the resulting gain.

  1. Heat roadmap China

    Xiong, Weiming; Wang, Yu; Mathiesen, Brian Vad;


    District heating is regarded as a key element of energy saving actions in the Chinese national energy strategy, while space heating in China is currently still dominated by coal boilers. However, there is no existing quantitative study to analyse the future heat strategy for China. Therefore, it ...

  2. Urban heat island

    Kim, Hongsuk H.


    The phenomenon of urban heat island was investigated by the use of LANDSAT Thematic Mapper data sets collected over the metropolitan area of Washington DC (U.S.). By combining the retrieved spectral albedos and temperatures, urban modification on radiation budgets of five surface categories were analyzed. The surface radiation budget imagery of the area show that urban heating is attributable to a large heat flux from the rapidly heating surfaces of asphalt, bare soil and short grass. In summer, symptoms of diurnal heating begin to appear by mid morning and can be about 10 degrees warmer than nearby woodlands in summer.

  3. Ground Source Heat Pumps

    Lale Valizade


    A heat pump is a device that is able to transfer heat from one fluid at a lower temperature to another at a higher temperature. Ground source heat pumps are generally classified by the type of ground loop. The coefficient of performance (COP) is used to define the heating performance of heat pumps. Both the COP and EER values are valid only at the specific test conditions used in the rating. A ground source pump could reach 450%, compared with an efficient gas boiler of 90% obviously this is ...

  4. Single Electrode Heat Effects

    Jacobsen, Torben; Broers, G. H. J.


    The heat evolution at a single irreversibly working electrode is treated onthe basis of the Brønsted heat principle. The resulting equation is analogous to the expression for the total heat evolution in a galvanic cellwith the exception that –DeltaS is substituted by the Peltier entropy, Delta......SP, of theelectrode reaction. eta is the overvoltage at the electrode. This equation is appliedto a high temperature carbonate fuel cell. It is shown that the Peltier entropyterm by far exceeds the heat production due to the irreversible losses, and thatthe main part of heat evolved at the cathode is...

  5. Comparison of heat transfer efficiency between heat pipe and tube bundles heat exchanger

    Wu Zhao-Chun; Zhu Xiang-Ping


    A comparison of heat transfer efficiency between the heat pipe and tube bundles heat exchanger is made based on heat transfer principle and the analysis of thermal characteristics. This paper argues that although heat pipe has the feature of high axial thermal conductivity, to those cases where this special function of heat transfer is unnecessary, heat pipe exchanger is not a high efficient heat exchanger when it is just used as a conventional heat exchang...

  6. Space Heating Equipment

    Rafferty, Kevin D.


    The performance evaluation of space heating equipment for a geothermal application is generally considered from either of two perspectives: (a) selecting equipment for installation in new construction, or (b) evaluating the performance and retrofit requirements of an existing system. With regard to new construction, the procedure is relatively straightforward. Once the heating requirements are determined, the process need only involve the selection of appropriately sized hot water heating equipment based on the available water temperature. It is important to remember that space heating equipment for geothermal applications is the same equipment used in non-geothermal applications. What makes geothermal applications unique is that the equipment is generally applied at temperatures and flow rates that depart significantly from traditional heating system design. This chapter presents general considerations for the performance of heating equipment at non-standard temperature and flow conditions, retrofit of existing systems, and aspects of domestic hot water heating.

  7. District heating versus local heating - Social supportability

    District heating, DH, is an energy source which can provide a cost-effective, environmentally friendly source of heat and power for cities, but only in the case of well running systems, with reasonable technological losses. The benefits of DH system are well known: environmental friendly, energy security, economic and social advantages. DH already covers 60% of heating and hot water needs in transition economies. Today, 70 % of Russian, Latvian and Belarus homes use DH, and heating accounts for one-third of total Russian energy consumption. Yet a large number of DH systems in the region face serious financial, marketing or technical problems because of the policy framework. How can DH issues be best addressed in national and local policy? What can governments do to create the right conditions for the sustainable development of DH while improving service quality? What policies can help capture the economic, environmental and energy security benefits of co-generation and DH? To address these questions, the International Energy Agency (IEA) hosted in 2002 and 2004 conference focusing on the crucial importance of well-designed DH policies, for exchanging information on policy approaches. The conclusions of the conference have shown that 'DH systems can do much to save energy and boost energy security, but stronger policy measures are needed to encourage wise management and investment. With a stronger policy framework, DH systems in formerly socialist countries could save the equivalent of 80 billion cubic meters of natural gas a year through supply side efficiency improvements. This is greater than total annual natural gas consumption in Italy'. More efficient systems will also decrease costs, reducing household bills and making DH competitive on long-term. This paper presents the issues: -Theoretical benefits of the district heating and cooling systems; - Municipal heating in Romania; - Technical and economic problems of DH systems and social supportability; - How

  8. Absorption heat pumps

    Huhtinen, M.; Heikkilae, M.; Andersson, R.


    The aim of the study was to analyze the technical and economic feasibility of absorption heat pumps in Finland. The work was done as a case study: the technical and economic analyses have been carried out for six different cases, where in each the suitable size and type of the heat pump plant and the auxiliary components and connections were specified. The study also detailed the costs concerning the procurement, installation and test runs of the machinery, as well as the savings in energy costs incurred by the introduction of the plant. Conclusions were drawn of the economic viability of the applications studied. The following cases were analyzed: heat recovery from flue gases and productin of district heat in plants using peat, natural gas, and municipal wastes as a fuel. Heat recovery in the pulp and paper industry for the upgrading of pressure of secondary steam and for the heating of white liquor and combustion and drying the air. Heat recovery in a peat-fulled heat and power plant from flue gases that have been used for the drying of peat. According to the study, the absorption heat pump suits best to the production of district heat, when the heat source is the primary energy is steam produced by the boiler. Included in the flue as condensing is the purification of flue gases. Accordingly, benefit is gained on two levels in thick applications. In heat and power plants the use of absorption heat pumps is less economical, due to the fact that the steam used by the pump reduces the production of electricity, which is rated clearly higher than heat.

  9. Experimental research on heat transfer in a coupled heat exchanger

    Liu Yin; Ma Jing; Zhou Guang-Hui; Guan Ren-Bo


    The heat exchanger is a devise used for transferring thermal energy between two or more different temperatures. The widespreadly used heat exchanger can only achieve heat exchange between two substances. In this paper, a coupled heat exchanger is proposed, which includes a finned heat exchanger and a double pipe heat exchanger, for multiple heat exchange simultaneously. An experiment is conducted, showing that the average heating capacity increases more tha...

  10. Heat pipe cooling system with sensible heat sink

    Silverstein, Calvin C.


    A heat pipe cooling system which employs a sensible heat sink is discussed. With this type of system, incident aerodynamic heat is transported via a heat pipe from the stagnation region to the heat sink and absorbed by raising the temperature of the heat sink material. The use of a sensible heat sink can be advantageous for situations where the total mission heat load is limited, as it is during re-entry, and a suitable radiation sink is not available.

  11. 24 CFR 3280.506 - Heat loss/heat gain.


    ... 24 Housing and Urban Development 5 2010-04-01 2010-04-01 false Heat loss/heat gain. 3280.506... URBAN DEVELOPMENT MANUFACTURED HOME CONSTRUCTION AND SAFETY STANDARDS Thermal Protection § 3280.506 Heat loss/heat gain. The manufactured home heat loss/heat gain shall be determined by methods outlined...

  12. Optimization of Heat Exchangers

    Ivan Catton


    The objective of this research is to develop tools to design and optimize heat exchangers (HE) and compact heat exchangers (CHE) for intermediate loop heat transport systems found in the very high temperature reator (VHTR) and other Generation IV designs by addressing heat transfer surface augmentation and conjugate modeling. To optimize heat exchanger, a fast running model must be created that will allow for multiple designs to be compared quickly. To model a heat exchanger, volume averaging theory, VAT, is used. VAT allows for the conservation of mass, momentum and energy to be solved for point by point in a 3 dimensional computer model of a heat exchanger. The end product of this project is a computer code that can predict an optimal configuration for a heat exchanger given only a few constraints (input fluids, size, cost, etc.). As VAT computer code can be used to model characteristics )pumping power, temperatures, and cost) of heat exchangers more quickly than traditional CFD or experiment, optimization of every geometric parameter simultaneously can be made. Using design of experiment, DOE and genetric algorithms, GE, to optimize the results of the computer code will improve heat exchanger disign.

  13. Heating load, heating-load density and COP optimizations of an endoreversible air heat-pump

    The finite-time thermodynamic performance has been studied of an endoreversible air heat-pump with constant-temperature heat-reservoirs. The heating load, the coefficient of performance (COP), and the heating-load density, i.e. the ratio of heating load to the maximum specific volume in the cycle, are the optimization objectives. The analytical formulae relating the heating load and pressure-ratio, between the COP and pressure-ratio, as well as between the heating-load density and pressure-ratio are derived assuming heat resistance losses occur in the hot- and cold-side heat-exchangers. The influences of the effectiveness of the heat-exchangers and the heat-reservoir temperature-ratio on the heating load, the COP and the heating-load density are analyzed. The cycle performance optimizations are performed by searching the optimal distribution of heat conductance of the hot- and cold-side heat-exchangers for the fixed total heat-exchanger inventory. The influences of some design parameters, including heat-capacity rate of the working fluid, heat-reservoir temperature-ratio and heat-exchanger inventory on the optimal distribution of heat conductance, the maximum heating load and the maximum heating-load density are indicated by numerical examples. The different results obtained from the heating-load optimization and the heating-load density optimization are shown. The air heat-pump design, with heat-loading density optimization, leads to smaller size equipment

  14. Silicon Heat Pipe Array

    Yee, Karl Y.; Ganapathi, Gani B.; Sunada, Eric T.; Bae, Youngsam; Miller, Jennifer R.; Beinsford, Daniel F.


    Improved methods of heat dissipation are required for modern, high-power density electronic systems. As increased functionality is progressively compacted into decreasing volumes, this need will be exacerbated. High-performance chip power is predicted to increase monotonically and rapidly with time. Systems utilizing these chips are currently reliant upon decades of old cooling technology. Heat pipes offer a solution to this problem. Heat pipes are passive, self-contained, two-phase heat dissipation devices. Heat conducted into the device through a wick structure converts the working fluid into a vapor, which then releases the heat via condensation after being transported away from the heat source. Heat pipes have high thermal conductivities, are inexpensive, and have been utilized in previous space missions. However, the cylindrical geometry of commercial heat pipes is a poor fit to the planar geometries of microelectronic assemblies, the copper that commercial heat pipes are typically constructed of is a poor CTE (coefficient of thermal expansion) match to the semiconductor die utilized in these assemblies, and the functionality and reliability of heat pipes in general is strongly dependent on the orientation of the assembly with respect to the gravity vector. What is needed is a planar, semiconductor-based heat pipe array that can be used for cooling of generic MCM (multichip module) assemblies that can also function in all orientations. Such a structure would not only have applications in the cooling of space electronics, but would have commercial applications as well (e.g. cooling of microprocessors and high-power laser diodes). This technology is an improvement over existing heat pipe designs due to the finer porosity of the wick, which enhances capillary pumping pressure, resulting in greater effective thermal conductivity and performance in any orientation with respect to the gravity vector. In addition, it is constructed of silicon, and thus is better

  15. Electricity and heat production

    Bohunice NPPs fulfilled planned power supply to 103.4% in 1997 having supplied 9,968,758 MWh to the national power grid. Bohunice NPPs power generation reached 10,796,904 MWh which represented 51% share of Slovak power stations plc power generation and 44% of national power generation. Total Bohunice NPPs production represented 178,715,793 MWh of power since the start-up of their WWER 440 units. Together with the A-1 plant it represented 180,180,372 MWh in total since the Bohunice site had been commissioned. Heat supply for heating purposes to the town of Trnava was reliable and met customer's requirements representing the amount of 1,003,500 GJ of heat, which was by 221,173 GJ less than in 1996. The heat supply to Trnava decreased due to the heat line from 13 May to 3 October 1997, due to starting the heat line to the towns of Hlohovec and Leopoldov up, and due to warmer weather during the heating season. The heat supply to Trnava represented 8,787,323 GJ since the Bohunice-Trnava heat line had been started up (December 1997). The Heat Transmission Plant Jaslovske Bohunice caught 65,687 GJ of heat last year which represented 310,982 GJ since its start-up (November 1992). Total heat supply from nuclear sources for heating purposes was 1,691,052 GJ in 1997, which represented 16,495,333 GJ since the Transmission Plant had been started up. Performance indicators from the beginning of operation to the end of 1997 and performance indicators in 1997 as well as operation history of Bohunice 1 - 4 reactor are presented

  16. Heat transfer from oriented heat exchange areas

    Vantuch, Martin; Huzvar, Jozef; Kapjor, Andrej


    This paper deals with the transfer of heat-driven heat transfer surface area in relation to the construction of the criterion equation for "n" horizontal pipe one about another. On the bases of theoretical models have been developed for calculating the thermal performance of natural convection by Churilla and Morgan, for various pipe diameters and temperatures. These models were compared with models created in CFD-Fluent Ansys the same boundary conditions. The aim of the analyse of heat and fluxional pipe fields "n" pipes one about another at natural convection is the creation of criterion equation on the basis of which the heat output of heat transfer from pipe oriented areas one above another with given spacing could be quantified. At presence a sum of criterion equations exists for simple geometrical shapes of individual oriented geometrical areas but the criterion equation which would consider interaction of fluxional field generated by free convection from multiple oriented areas is not mentioned in standardly accessible technical literature and other magazine publications.

  17. Floor heating maximizes residents` comfort

    Tirkkanen, P.; Wikstroem, T.


    Storing heat in floors by using economical night-time electricity does not increase the specific consumption of heating. According to studies done by IVO, the optimum housing comfort is achieved if the room is heated mainly by means of floor heating that is evened out by window or ceiling heating, or by a combination of all three forms of heating. (orig.)

  18. Support for heat exchangers

    The very large heat exchangers which are typical of many nuclear power plants place great demands on their supports. The support here described is for a vertical heat exchanger. A convex Lubrit plate allows a certain amount of transverse and rotational movement of the heat exhanger relative to the foundation. Taps engaging in the support surface of the heat exchanger and between the support box and the concrete foundation ensure that relative movement is restricted to those surfaces where it is intended. A steel box structure embedded in the concrete foundation dissipates heat transferred through the support system and avoids overheating the concrete. Horizontal stays support the heat exchanger against the concrete walls. (JIW)


    Lenert, Andrej; Nam, Youngsuk; Wang, Evelyn N.


    The choice of heat transfer fluids has significant effects on the performance, cost, and reliability of solar thermal systems. In this chapter, we evaluate existing heat transfer fluids such as oils and molten salts based on a new figure of merit capturing the combined effects of thermal storage capacity, convective heat transfer characteristics, and hydraulic performance of the fluids. Thermal stability, freezing point, and safety issues are also discussed. Through a comparative analysis, we...

  20. Convection heat transfer

    Bejan, Adrian


    Written by an internationally recognized authority on heat transfer and thermodynamics, this second edition of Convection Heat Transfer contains new and updated problems and examples reflecting real-world research and applications, including heat exchanger design. Teaching not only structure but also technique, the book begins with the simplest problem solving method (scale analysis), and moves on to progressively more advanced and exact methods (integral method, self similarity, asymptotic behavior). A solutions manual is available for all problems and exercises.

  1. Mechanisms of Coronal Heating

    S. R. Verma


    The Sun is a mysterious star. The high temperature of the chromosphere and corona present one of the most puzzling problems of solar physics. Observations show that the solar coronal heating problem is highly complex with many different facts. It is likely that different heating mechanisms are at work in solar corona. Recent observations show that Magnetic Carpet is a potential candidate for solar coronal heating.

  2. NCSX Plasma Heating Methods

    H.W. Kugel; D. Spong; R. Majeski; M. Zarnstorff


    The NCSX (National Compact Stellarator Experiment) has been designed to accommodate a variety of heating systems, including ohmic heating, neutral-beam injection, and radio-frequency. Neutral beams will provide one of the primary heating methods for NCSX. In addition to plasma heating, beams are also expected to provide a means for external control over the level of toroidal plasma rotation velocity and its profile. The plan is to provide 3 MW of 50 keV balanced neutral-beam tangential injection with pulse lengths of 500 msec for initial experiments, and to be upgradeable to pulse lengths of 1.5 sec. Subsequent upgrades will add 3 MW of neutral-beam injection. This Chapter discusses the NCSX neutral-beam injection requirements and design issues, and shows how these are provided by the candidate PBX-M (Princeton Beta Experiment-Modification) neutral-beam injection system. In addition, estimations are given for beam-heating efficiencies, scaling of heating efficiency with machine size an d magnetic field level, parameter studies of the optimum beam-injection tangency radius and toroidal injection location, and loss patterns of beam ions on the vacuum chamber wall to assist placement of wall armor and for minimizing the generation of impurities by the energetic beam ions. Finally, subsequent upgrades could add an additional 6 MW of radio-frequency heating by mode-conversion ion-Bernstein wave (MCIBW) heating, and if desired as possible future upgrades, the design also will accommodate high-harmonic fast-wave and electron-cyclotron heating. The initial MCIBW heating technique and the design of the radio-frequency system lend themselves to current drive, so that if current drive became desirable for any reason only minor modifications to the heating system described here would be needed. The radio-frequency system will also be capable of localized ion heating (bulk or tail), and possibly ion-Bernstein-wave-generated sheared flows.

  3. Heat and thermodynamics

    Saxena, A K


    Heat and thermodynamics aims to serve as a textbook for Physics, Chemistry and Engineering students. The book covers basic ideas of Heat and Thermodynamics, Kinetic Theory and Transport Phenomena, Real Gases, Liquafaction and Production and Measurement of very Low Temperatures, The First Law of Thermodynamics, The Second and Third Laws of Thermodynamics and Heat Engines and Black Body Radiation. KEY FEATURES Emphasis on concepts Contains 145 illustrations (drawings), 9 Tables and 48 solved examples At the end of chapter exercises and objective questions

  4. Counterflow Regolith Heat Exchanger

    Zubrin, Robert; Jonscher, Peter


    A problem exists in reducing the total heating power required to extract oxygen from lunar regolith. All such processes require heating a great deal of soil, and the heat energy is wasted if it cannot be recycled from processed material back into new material. The counterflow regolith heat exchanger (CoRHE) is a device that transfers heat from hot regolith to cold regolith. The CoRHE is essentially a tube-in-tube heat exchanger with internal and external augers attached to the inner rotating tube to move the regolith. Hot regolith in the outer tube is moved in one direction by a right-hand - ed auger, and the cool regolith in the inner tube is moved in the opposite direction by a left-handed auger attached to the inside of the rotating tube. In this counterflow arrangement, a large fraction of the heat from the expended regolith is transferred to the new regolith. The spent regolith leaves the heat exchanger close to the temperature of the cold new regolith, and the new regolith is pre-heated close to the initial temperature of the spent regolith. Using the CoRHE can reduce the heating requirement of a lunar ISRU system by 80%, reducing the total power consumption by a factor of two. The unique feature of this system is that it allows for counterflow heat exchange to occur between solids, instead of liquids or gases, as is commonly done. In addition, in variants of this concept, the hydrogen reduction can be made to occur within the counterflow heat exchanger itself, enabling a simplified lunar ISRU (in situ resource utilization) system with excellent energy economy and continuous nonbatch mode operation.

  5. Microplate Heat Exchanger Project

    National Aeronautics and Space Administration — We propose a microplate heat exchanger for cryogenic cooling systems used for continuous flow distributed cooling systems, large focal plane arrays, multiple...

  6. Heat Pipe Materials Compatibility

    Eninger, J. E.; Fleischman, G. L.; Luedke, E. E.


    An experimental program to evaluate noncondensable gas generation in ammonia heat pipes was completed. A total of 37 heat pipes made of aluminum, stainless steel and combinations of these materials were processed by various techniques, operated at different temperatures and tested at low temperature to quantitatively determine gas generation rates. In order of increasing stability are aluminum/stainless combination, all aluminum and all stainless heat pipes. One interesting result is the identification of intentionally introduced water in the ammonia during a reflux step as a means of surface passivation to reduce gas generation in stainless-steel/aluminum heat pipes.

  7. Heat rejection system

    Smith, Gregory C.; Tokarz, Richard D.; Parry, Jr., Harvey L.; Braun, Daniel J.


    A cooling system for rejecting waste heat consists of a cooling tower incorporating a plurality of coolant tubes provided with cooling fins and each having a plurality of cooling channels therein, means for directing a heat exchange fluid from the power plant through less than the total number of cooling channels to cool the heat exchange fluid under normal ambient temperature conditions, means for directing water through the remaining cooling channels whenever the ambient temperature rises above the temperature at which dry cooling of the heat exchange fluid is sufficient and means for cooling the water.

  8. Heat Capacity Analysis Report

    The purpose of this report is to provide heat capacity values for the host and surrounding rock layers for the waste repository at Yucca Mountain. The heat capacity representations provided by this analysis are used in unsaturated zone (UZ) flow, transport, and coupled processes numerical modeling activities, and in thermal analyses as part of the design of the repository to support the license application. Among the reports that use the heat capacity values estimated in this report are the ''Multiscale Thermohydrologic Model'' report, the ''Drift Degradation Analysis'' report, the ''Ventilation Model and Analysis Report, the Igneous Intrusion Impacts on Waste Packages and Waste Forms'' report, the ''Dike/Drift Interactions report, the Drift-Scale Coupled Processes (DST and TH Seepage) Models'' report, and the ''In-Drift Natural Convection and Condensation'' report. The specific objective of this study is to determine the rock-grain and rock-mass heat capacities for the geologic stratigraphy identified in the ''Mineralogic Model (MM3.0) Report'' (BSC 2004 [DIRS 170031], Table 1-1). This report provides estimates of the heat capacity for all stratigraphic layers except the Paleozoic, for which the mineralogic abundance data required to estimate the heat capacity are not available. The temperature range of interest in this analysis is 25 C to 325 C. This interval is broken into three separate temperature sub-intervals: 25 C to 95 C, 95 C to 114 C, and 114 C to 325 C, which correspond to the preboiling, trans-boiling, and postboiling regimes. Heat capacity is defined as the amount of energy required to raise the temperature of a unit mass of material by one degree (Nimick and Connolly 1991 [DIRS 100690], p. 5). The rock-grain heat capacity is defined as the heat capacity of the rock solids (minerals), and does not include the effect of water that exists in the rock pores. By comparison, the rock-mass heat capacity considers the heat capacity of both solids and pore

  9. Heat transfer dynamics

    As heat transfer technology increases in complexity, it becomes more difficult for those without thermal dynamics engineering training to choose between competitive heat transfer systems offered to meet their drying requirements. A step back to the basics of heat transfer can help professional managers and papermakers make informed decisions on alternative equipment and methods. The primary forms of heat and mass transfer are reviewed with emphasis on the basics, so a practical understanding of each is gained. Finally, the principles and benefits of generating infrared energy by combusting a gaseous hydrocarbon fuel are explained

  10. Heat pipe technology issues

    Critical high temperature, high power applications in space nuclear power designs are near the current state of the art of heat pipe technology in terms of power density, operating temperature, and lifetime. Recent heat pipe development work at Los Alamos National Laboratory has involved performance testing of typical space reactor heat pipe designs to power levels in excess of 19 kW/cm2 axially and 300 W/cm2 radially at temperatures in the 1400 to 1500 K range. Operation at conditions in the 10 kW/cm2 range has been sustained for periods of up to 1000 hours without evidence of performance degradation. The effective length for heat transport in these heat pipes was from 1.0 to 1.5 M. Materials used were molybdenum alloys with lithium employed as the heat pipe operating fluid. Shorter, somewhat lower power, molybdenum heat pipes have been life tested at Los Alamos for periods of greater than 25,000 hours at 1700 K with lithium and 20,000 hours at 15000K with sodium. These life test demonstrations and the attendant performance limit investigations provide an experimental basis for heat pipe application in space reactor design and represent the current state-of-the-art of high temperature heat pipe technology

  11. Mesoscopic photon heat transistor

    Ojanen, T.; Jauho, Antti-Pekka


    We show that the heat transport between two bodies, mediated by electromagnetic fluctuations, can be controlled with an intermediate quantum circuit-leading to the device concept of a mesoscopic photon heat transistor (MPHT). Our theoretical analysis is based on a novel Meir-Wingreen-Landauer-typ......We show that the heat transport between two bodies, mediated by electromagnetic fluctuations, can be controlled with an intermediate quantum circuit-leading to the device concept of a mesoscopic photon heat transistor (MPHT). Our theoretical analysis is based on a novel Meir...

  12. Introduction to Heat Pipes

    Ku, Jentung


    This is the presentation file for the short course Introduction to Heat Pipes, to be conducted at the 2015 Thermal Fluids and Analysis Workshop, August 3-7, 2015, Silver Spring, Maryland. NCTS 21070-15. Course Description: This course will present operating principles of the heat pipe with emphases on the underlying physical processes and requirements of pressure and energy balance. Performance characterizations and design considerations of the heat pipe will be highlighted. Guidelines for thermal engineers in the selection of heat pipes as part of the spacecraft thermal control system, testing methodology, and analytical modeling will also be discussed.

  13. Heating uranium alloy billets

    Data were obtained for the surface heat transfer coefficient of uranium and the alloys of uranium-0.75 wt percent titanium, uranium-6 wt percent niobium, and uranium-7.5 wt percent niobium-2.5 wt percent zirconium. Samples were heated to 8500C in both a molten salt bath and an argon-purged air furnace, then the samples were cooled in air. Surface heat transfer coefficients were calculated from the experimental data for both heating and cooling of the metals. 4 fig, 4 tables

  14. Lunar Base Heat Pump

    Walker, D.; Fischbach, D.; Tetreault, R.


    The objective of this project was to investigate the feasibility of constructing a heat pump suitable for use as a heat rejection device in applications such as a lunar base. In this situation, direct heat rejection through the use of radiators is not possible at a temperature suitable for lde support systems. Initial analysis of a heat pump of this type called for a temperature lift of approximately 378 deg. K, which is considerably higher than is commonly called for in HVAC and refrigeration applications where heat pumps are most often employed. Also because of the variation of the rejection temperature (from 100 to 381 deg. K), extreme flexibility in the configuration and operation of the heat pump is required. A three-stage compression cycle using a refrigerant such as CFC-11 or HCFC-123 was formulated with operation possible with one, two or three stages of compression. Also, to meet the redundancy requirements, compression was divided up over multiple compressors in each stage. A control scheme was devised that allowed these multiple compressors to be operated as required so that the heat pump could perform with variable heat loads and rejection conditions. A prototype heat pump was designed and constructed to investigate the key elements of the high-lift heat pump concept. Control software was written and implemented in the prototype to allow fully automatic operation. The heat pump was capable of operation over a wide range of rejection temperatures and cooling loads, while maintaining cooling water temperature well within the required specification of 40 deg. C +/- 1.7 deg. C. This performance was verified through testing.

  15. Passive Vaporizing Heat Sink

    Knowles, TImothy R.; Ashford, Victor A.; Carpenter, Michael G.; Bier, Thomas M.


    A passive vaporizing heat sink has been developed as a relatively lightweight, compact alternative to related prior heat sinks based, variously, on evaporation of sprayed liquids or on sublimation of solids. This heat sink is designed for short-term dissipation of a large amount of heat and was originally intended for use in regulating the temperature of spacecraft equipment during launch or re-entry. It could also be useful in a terrestrial setting in which there is a requirement for a lightweight, compact means of short-term cooling. This heat sink includes a hermetic package closed with a pressure-relief valve and containing an expendable and rechargeable coolant liquid (e.g., water) and a conductive carbon-fiber wick. The vapor of the liquid escapes when the temperature exceeds the boiling point corresponding to the vapor pressure determined by the setting of the pressure-relief valve. The great advantage of this heat sink over a melting-paraffin or similar phase-change heat sink of equal capacity is that by virtue of the =10x greater latent heat of vaporization, a coolant-liquid volume equal to =1/10 of the paraffin volume can suffice.

  16. Introductory heat-transfer

    Widener, Edward L.


    The objective is to introduce some concepts of thermodynamics in existing heat-treating experiments using available items. The specific objectives are to define the thermal properties of materials and to visualize expansivity, conductivity, heat capacity, and the melting point of common metals. The experimental procedures are described.

  17. Heat exchangers: operation problems

    The main operation problems for heat exchangers are fouling, corrosion, vibrations and mechanical resistance. Fouling and corrosion lead to an over dimensioning, energy consumption increase, corroded pieces change, shutdown costs. Vibrations are taken in account during the dimensioning phase of the heat exchangers. Mechanical resistance problems are, for the classical ones, described in regulation texts. (A.B.). 5 figs., 4 tabs

  18. Heat-Related Illnesses

    Full Text Available ... So Long? Admission to the Hospital Heroes on Medicine's Front Line Observation Emergency Care Fact Sheet ... Heat-Related Illnesses Dr. Glenn Mitchell , Emergency physician at Mercy Health System in Chesterfield, Missouri Heat-related illness can be ...

  19. Heat pipe technology issues

    Recent heat pipe development work at Los Alamos National Laboratory as involved performance testing of typical space reactor heat pipe designs to power levels in excess of 19 kW/cm2 axially and 300 W/cm2 radially at temperatures in the 1400 to 15000K range. Operation at conditions in the 10 kW/cm2 range has been sustained for periods of up to 1000 hours without evidence of performance degradation. The effective length for heat transport in these heat pipes was from 1.0 to 1.5 M. Materials used were molybdenum alloys with lithium employed as the heat pipe operating fluid. Shorter, somewhat lower power density, molybdenum heat pipes have been life tested at Los Alamos for periods of greater than 25,000 hours at 17000K with lithium and 20,000 hours at 15000K with sodium. These life test demonstrations and the attendant performance limit investigations provide an experimental basis for heat pipe application in space reactor design and represent the current state-of-the-art of high temperature heat pipe technology. 9 refs., 11 figs

  20. Radioisotopic heat source

    Disclosed is a radioisotopic heat source and method for a long life electrical generator. The source includes plutonium dioxide shards and yttrium or hafnium in a container of tantalum-tungsten-hafnium alloy, all being in a nickel alloy outer container, and subjected to heat treatment of from about 15700F to about 17200F for about one h

  1. Solar Heating System with Building-Integrated Heat Storage

    Heller, Alfred


    Traditional solar heating systems cover between 5 and 10% of the heat demand fordomestic hot water and comfort heating. By applying storage capacity this share can beincreased much. The Danish producer of solar heating systems, Aidt-Miljø, markets such a system including storage of dry sand heated...... by PP-pipe heat exchanger. Heat demand is reduced due to direct solar heating, and due to storage. Heat demand is reduced due to direct solar heating, due to storage and due to lower heat losses through the ground. In theory, by running the system flow backwards through the sand storage, active heating...... can be achieved.The objective of the report is to present results from measured system evaluation andcalculations and to give guidelines for the design of such solar heating systems with building integrated sand storage. The report is aimed to non-technicians. In another report R-006 the main results...

  2. Process heat reactors

    The consumption of heat, for industrial and domestic needs, takes up half of the national energy supply; direct utilization of the heat produced by nuclear reactors could therefore contribute to reduce the deficit in the energetic results. The restraints proper to heat consumption (dispersal and variety of consumers, irregular demand) involve the development of the heat transport system structures and adequate nuclear reactors. With this in view, the Commissariat a l'Energie Atomique and Technicatome are developing the CAS reactor series, pressurized water reactors (PWR), (CAS 3G reactor with a power of 420, and the Thermos reactor (100, directly conceived to produce heat at 1200C and whose technology derives from the experimental pool reactors type. In order to prove the value of the Thermos design, an experimental reactor should soon be constructed in the Saclay nuclear research centre

  3. ICRF heating in DIVA

    ICRF Heating of impurity-free tokamak plasmas has been studied in DIVA. The frequency is fixed at 25 MHz, which is a second harmonic cyclotron frequency of deuterons with a toroidal magnetic field of 16.4 kG. (1) Optimum heating conditions were investigated in varying the toroidal magnetic field B sub( t) and the proton-to-deuteron density ratio epsilon sub(p). The most favorable ion heating is observed for B sub( t) -- 18 kG and epsilon sub(p) = 5 -- 10%, which is explained by two-ion hybrid effects. (2) In heating results after improvement of the coupling structure, the ion heating efficiency is raised from 40% to almost 100%. Bulk ion temperature increased by a factor of 2.7 in application of the rf net power of 180 kW including the circuit loss. (author)

  4. Heat Pipe Systems


    The heat pipe was developed to alternately cool and heat without using energy or any moving parts. It enables non-rotating spacecraft to maintain a constant temperature when the surface exposed to the Sun is excessively hot and the non Sun-facing side is very cold. Several organizations, such as Tropic-Kool Engineering Corporation, joined NASA in a subsequent program to refine and commercialize the technology. Heat pipes have been installed in fast food restaurants in areas where humid conditions cause materials to deteriorate quickly. Moisture removal was increased by 30 percent in a Clearwater, FL Burger King after heat pipes were installed. Relative humidity and power consumption were also reduced significantly. Similar results were recorded by Taco Bell, which now specifies heat pipe systems in new restaurants in the Southeast.

  5. Advanced heat pump

    Ashley, Joseph L.; Matthews, John D.


    This patent application discloses a heat pump which includes a first packed bed of liquid desiccant for removing moisture from outside air in the heating mode of operation, and a pump for transferring the moisture laden desiccant to a second packed bed which humidifies condenser heated inside air by adding water vapor to the air. The first packed bed, by removing moisture from the outside air before it passes through the heat pump's evaporator coils, prevents frost from forming on the coils. In the cooling mode of operation the second packed bed of liquid desiccant removes water vapor from the air inside of the building. The moisture laden desiccant is then transferred to the first packed bed by a second pump where condenser heat transfers the moisture from the desiccant to outside air.

  6. Heat pipes and use of heat pipes in furnace exhaust

    Polcyn, Adam D.


    An array of a plurality of heat pipe are mounted in spaced relationship to one another with the hot end of the heat pipes in a heated environment, e.g. the exhaust flue of a furnace, and the cold end outside the furnace. Heat conversion equipment is connected to the cold end of the heat pipes.

  7. An important feature of air heat pump cycle: Heating capacity in line with heating load

    In the conventional vapor-compression heat pumps, the heating capacity and the heating load usually vary in opposite directions, which results in a mismatch of the heating capacity and the heating load at off-design conditions. Air (reversed Brayton) cycle is a potential substitute for the conventional vapor-compression cycles. This paper proved that in theory the air heat pump cycle can make the heating capacity in line with the heating load at a stable level of heating COP (coefficient of performance). A thermodynamic model for the air heat pump cycle with practical compressor and expander was developed. The optimal heating COP and the corresponding pressure ratio were derived from the model. Then the cycle performance was analytically expressed under the optimal COP conditions. The heating capacity under different operating conditions was found in line with the heating load. Comparisons between the air heat pump cycle and two typical vapor-compression heat pump cycles were numerically done for further verification. It also turned out that the energy efficiency of air heat pump is comparable to the transcritical CO2 heat pump, particularly at large temperature difference. - Highlights: • We developed a thermodynamic model for air heat pump cycle. • The optimal COP (coefficient of performance) was derived and the corresponding cycle performance was analyzed. • Comparison of air heat pump cycle and vapor-compression cycles was numerically done. • We proved air heat pump cycle can make heating capacity in line with heating load

  8. Acoustically enhanced heat transport

    Ang, Kar M.; Hung, Yew Mun; Tan, Ming K., E-mail: [School of Engineering, Monash University Malaysia, 47500 Bandar Sunway, Selangor (Malaysia); Yeo, Leslie Y. [Micro/Nanophysics Research Laboratory, RMIT University, Melbourne, VIC 3001 (Australia); Friend, James R. [Department of Mechanical and Aerospace Engineering, University of California, San Diego, California 92093 (United States)


    We investigate the enhancement of heat transfer in the nucleate boiling regime by inducing high frequency acoustic waves (f ∼ 10{sup 6} Hz) on the heated surface. In the experiments, liquid droplets (deionized water) are dispensed directly onto a heated, vibrating substrate. At lower vibration amplitudes (ξ{sub s} ∼ 10{sup −9} m), the improved heat transfer is mainly due to the detachment of vapor bubbles from the heated surface and the induced thermal mixing. Upon increasing the vibration amplitude (ξ{sub s} ∼ 10{sup −8} m), the heat transfer becomes more substantial due to the rapid bursting of vapor bubbles happening at the liquid-air interface as a consequence of capillary waves travelling in the thin liquid film between the vapor bubble and the air. Further increases then lead to rapid atomization that continues to enhance the heat transfer. An acoustic wave displacement amplitude on the order of 10{sup −8} m with 10{sup 6} Hz order frequencies is observed to produce an improvement of up to 50% reduction in the surface temperature over the case without acoustic excitation.

  9. Fluidised bed heat exchangers

    Problems that have arisen during the initial stages of development of fluidised bed boilers in which heat transfer surfaces are immersed in fluidised solids are discussed. The very high heat transfer coefficients that are obtained under these conditions can be exploited to reduce the total heat transfer surface to a fraction of that in normal boilers. However, with the high heat flux levels involved, tube stressing becomes more important and it is advantageous to use smaller diameter tubes. One of the initial problems was that the pumping power absorbed by the fluidised bed appeared to be high. The relative influence of the fluidising velocity (and the corresponding bed area), tube diameter, tube spacing, heat transfer coefficient and bed temperature on pumping power and overall cost was determined. This showed the importance of close tube packing and research was undertaken to see if this would adversely affect the heat transfer coefficient. Pressure operation also reduces the pumping power. Fouling and corrosion tests in beds burning coal suggest that higher temperatures could be reached reliably and cost studies show that, provided the better refractory metals are used, the cost of achieving higher temperatures is not unduly high. It now remains to demonstrate at large scale that the proposed systems are viable and that the methods incorporated to overcome start up and part lead running problems are satisfactory. The promising role of these heat transfer techniques in other applications is briefly discussed

  10. Heat recovery apparatus

    Heat transfer is a living science and technical advances are constantly being made. However, in many cases, progress is limited by the equipment that is available on the market, rather than by knowledge of the heat transfer process. A case in point is the design of economizers: in such equipment a small quantity of water (with a relatively good heat transfer coefficient) is heated by a large quantity of low-pressure gas (with an inherently low heat transfer coefficient). As a first step in design finned tubing is used to lessen the discrepancy in coefficients. From this point, it becomes apparent that the equipment consists of a small number of tubes (to maintain good velocity on the water side) of considerable length (to provide sufficient area). In the process industries the base pressure, though low, may be in the region of 0.5 bar, and there is no convenient flue in which to place the heat recovery coil. It is therefore contained in a flat-sided enclosure, which is ill-fitted to pressure containment and is therefore reinforced with a plethora of structural sections. Such inelegant construction is quite common in North America; in Europe, cylindrical containments of vast size have been supplied for the same purposes. The real shortcoming is a successful marriage of different disciplines to produce reliable and efficient heat transfer equipment suitably contained

  11. Chapter 11. Heat Exchangers

    Rafferty, Kevin D.; Culver, Gene


    Most geothermal fluids, because of their elevated temperature, contain a variety of dissolved chemicals. These chemicals are frequently corrosive toward standard materials of construction. As a result, it is advisable in most cases to isolate the geothermal fluid from the process to which heat is being transferred. The task of heat transfer from the geothermal fluid to a closed process loop is most often handled by a plate heat exchanger. The two most common types used in geothermal applications are: bolted and brazed. For smaller systems, in geothermal resource areas of a specific character, downhole heat exchangers (DHEs) provide a unique means of heat extraction. These devices eliminate the requirement for physical removal of fluid from the well. For this reason, DHE-based systems avoid entirely the environmental and practical problems associated with fluid disposal. Shell and tube heat exchangers play only a minor role in low-temperature, direct-use systems. These units have been in common use in industrial applications for many years and, as a result, are well understood. For these reasons, shell and tube heat exchangers will not be covered in this chapter.

  12. Soil Heat Flow Model

    Varas, E.; Nunez, C.; Meza, F. J.


    The Penman-Monteith method for estimating evapotranspiration (ET) has been recommended by FAO. This method requires measures of temperature, wind speed, relative humidity and heat flow in the soil. This last variable is rarely available. Soil heat flow is generally small compared to the net radiation, and many times is ignored in the energy balance. Nevertheless, the addition or subtraction of this amount in the energy balance equation should be considered for evapo-transpiration calculation. Penman-Monteith method suggests approximate estimates of soil heat flows as the difference between the maxima and minimum daily temperatures multiplied by a convenient coefficient. However, such approach ignores important variations in this parameter occurring during the day, and could influence the accuracy of the result. This work proposes to estimate soil heat flows by means of a mathematical model that includes the estimate of soil temperatures profiles and heat flows as a function of thermal properties of the soil, such as difussivity and conductivity coefficients. The model calculates soil heat flows in three stages. The first estimates hourly air temperature based on the average daily temperature and Fourier series coefficients. The obtained hourly air temperature constitutes an input variable for the second stage of the model. Surface soil temperature is assumed to be equal to air temperature. The second stage, applies heat transfer principles, using the thermal properties of the soil in order to obtain the soil temperature profile in a one meter depth soil stratum. Finally, the results of the second stage are used to calculate the hourly heat flow in the soil and compare this estimate with other methods and with measured values. Calculated hourly temperatures reproduced observed values closely. Correlation coefficients between observed and calculated values for the three summer months are 0.98, 0.96 and 0.97. Hourly soil heat fluxes are also closely estimated, showing

  13. Supply temperature control concepts in heat pump heating systems

    Huchtemann, Kristian


    In recent years, electrically driven compression heat pumps have come to be widely used for the heating of buildings. Their efficiency strongly depends on the temperature lift which is influenced by the supply temperature of the heat sink. When used with radiator heating systems it is challenging to operate heat pumps efficiently because high supply temperatures are required. Therefore, in order to efficiently operate heat pumps, this work analyses advanced control concepts for heatpump heati...

  14. Optimal heat transport

    Souza, Andre; Doering, Charles R.


    The transport of heat by buoyancy driven flows, i.e., thermal convection plays a central role in many natural phenomena and an understanding of how to control its mechanisms is relevant to many engineering applications. In this talk we will consider a variational formulation of optimal heat transport in simple geometries. Numerical results, limits on heat transport, and a comparison to Rayleigh-Bénard convection will be presented. Research supported by NSF Awards PHY-1205219, PHY-1338407, PHY-1443836, PHY-1533555 and DMS-1515161.

  15. Episodic coronal heating

    Sturrock, P. A.; Dixon, W. W.; Klimchuk, J. A.; Antiochos, S. K.


    A study is made of the observational consequences of the hypothesis that there is no steady coronal heating, the solar corona instead being heated episodically, such that each short burst of heating is followed by a long period of radiative cooling. The form of the resulting contribution to the differential emission measure (DEM), and to a convenient related function (the differential energy flux, DEF) is calculated. Observational data for the quiet solar atmosphere indicate that the upper branch of the DEM, corresponding to temperatures above 100,000 K, can be interpreted in terms of episodic energy injection at coronal temperatures.

  16. Heat exchanger design handbook

    Thulukkanam, Kuppan


    Completely revised and updated to reflect current advances in heat exchanger technology, Heat Exchanger Design Handbook, Second Edition includes enhanced figures and thermal effectiveness charts, tables, new chapter, and additional topics--all while keeping the qualities that made the first edition a centerpiece of information for practicing engineers, research, engineers, academicians, designers, and manufacturers involved in heat exchange between two or more fluids.See What's New in the Second Edition: Updated information on pressure vessel codes, manufacturer's association standards A new c

  17. Heat pump planning handbook

    Bonin, Jürgen


    The Heat Pump Planning Handbook contains practical information and guidance on the design, planning and selection of heat pump systems, allowing engineers, designers, architects and construction specialists to compare a number of different systems and options. Including detailed descriptions of components and their functions and reflecting the current state of technology this guide contains sample tasks and solutions as well as new model calculations and planning evaluations. Also economic factors and alternative energy sources are covered, which are essential at a time of rising heat costs. T

  18. Waste heat recovery system

    Full text: The Konzen in-house designed anaerobic digester system for the POME (Palm Oil Mill Effluent) treatment process is one of the registered Clean Development Mechanism (CDM) projects in Malaysia. It is an organic wastewater treatment process which achieves excellent co-benefits objectives through the prevention of water pollution and reduction of greenhouse gas emissions, which is estimated to be 40,000 to 50,000 t-CO2 per year. The anaerobic digester was designed in mesophile mode with temperature ranging from 37 degree Celsius to 45 degree Celsius. A microorganisms growth is optimum under moderately warm temperature conditions. The operating temperature of the anaerobic digester needs to be maintained constantly. There are two waste heat recovery systems designed to make the treatment process self-sustaining. The heat recovered will be utilised as a clean energy source to heat up the anaerobic digester indirectly. The first design for the waste heat recovery system utilises heat generated from the flue gas of the biogas flaring system. A stainless steel water tank with an internal water layer is installed at the top level of the flare stack. The circulating water is heated by the methane enriched biogas combustion process. The second design utilizes heat generated during the compression process for the biogas compressor operation. The compressed biogas needs to be cooled before being recycled back into the digester tank for mixing purposes. Both the waste heat recovery systems use a design which applies a common water circulation loop and hot water tank to effectively become a closed loop. The hot water tank will perform both storage and temperature buffer functions. The hot water is then used to heat up recycled sludge from 30 degree Celsius to 45 degree Celsius with the maximum temperature setting at 50 degree Celsius. The recycled sludge line temperature will be measured and monitored by a temperature sensor and transmitter, which will activate the

  19. Episodic coronal heating

    A study is made of the observational consequences of the hypothesis that there is no steady coronal heating, the solar corona instead being heated episodically, such that each short burst of heating is followed by a long period of radiative cooling. The form of the resulting contribution to the differential emission measure (DEM), and to a convenient related function (the differential energy flux, DEF) is calculated. Observational data for the quiet solar atmosphere indicate that the upper branch of the DEM, corresponding to temperatures above 100,000 K, can be interpreted in terms of episodic energy injection at coronal temperatures. 22 refs

  20. Heat conduction in nanofluids

    Wang Liqiu [Department of Mechanical Engineering, University of Hong Kong, Pokfulam Road (Hong Kong)], E-mail:; Wei Xiaohao [Department of Mechanical Engineering, University of Hong Kong, Pokfulam Road (Hong Kong)


    We show that macroscale heat conduction in nanofluids is of a dual-phase-lagging type rather than the Fourier type. This leads to models for effective thermal capacity, conductivity and diffusivity of nanofluids and reveals even more anomalous thermal behavior of nanofluids than those reported in the literature. Due to the coupled conduction of the two phases, thermal waves and possibly resonance may appear in nanofluid heat conduction. Such waves and resonance are responsible for the extraordinary conductivity enhancement. The analysis and result are also valid for heat conduction in two-phase systems.

  1. Primary energy savings using heat storage for biomass heating systems

    Mitrović Dejan M.; Janevski Jelena N.; Laković Mirjana S.


    District heating is an efficient way to provide heat to residential, tertiary and industrial users. The heat storage unit is an insulated water tank that absorbs surplus heat from the boiler. The stored heat in the heat storage unit makes it possible to heat even when the boiler is not working, thus increasing the heating efficiency. In order to save primary energy (fuel), the boiler operates on nominal load every time it is in operation (for the purpose of this research). The aim of th...

  2. Counterflow Regolith Heat Exchanger Project

    National Aeronautics and Space Administration — The counterflow regolith heat exchanger (CoRHE) is a device that transfers heat from hot regolith to cold regolith. The CoRHE is essentially a tube-in-tube heat...

  3. Heat Stress in Older Adults

    ... Landslides Tornadoes Tsunamis Volcanoes Wildfires Winter Weather Heat Stress in Older Adults Recommend on Facebook Tweet Share ... What You Can Do for Someone With Heat Stress If you see any signs of severe heat ...

  4. Heat tolerance in wheat

    Sharma, Dew Kumari

    As a consequence of global climate change, heat stress together with other abiotic stresses will remain an important determinant of future food security. Wheat (Triticum aestivum L.) is the third most important crop of the world feeding one third of the world population. Being a crop of temperate...... climate, wheat is sensitive to heat stress. We need to understand how our crops will perform in these changing climatic conditions and how we can develop varieties, which are more tolerant. The PhD study focussed on understanding heat tolerance in wheat with a combined approach of plant physiology and...... genetic determination (GD). An initial mass screening of 1,274 wheat cultivars (diverse origin) showed a GD of 8.5%. A stronger heat treatment was given in the second screening with 138 selected cultivars resulting in larger differentiation of cultivars (GD 15.4%). The GD further increased to 27.9% in the...

  5. Radiative heat transfer

    Modest, Michael F


    The third edition of Radiative Heat Transfer describes the basic physics of radiation heat transfer. The book provides models, methodologies, and calculations essential in solving research problems in a variety of industries, including solar and nuclear energy, nanotechnology, biomedical, and environmental. Every chapter of Radiative Heat Transfer offers uncluttered nomenclature, numerous worked examples, and a large number of problems-many based on real world situations-making it ideal for classroom use as well as for self-study. The book's 24 chapters cover the four major areas in the field: surface properties; surface transport; properties of participating media; and transfer through participating media. Within each chapter, all analytical methods are developed in substantial detail, and a number of examples show how the developed relations may be applied to practical problems. It is an extensive solution manual for adopting instructors. Features: most complete text in the field of radiative heat transfer;...

  6. Heat-Related Illnesses

    Full Text Available ... Care Fact Sheet Health & Safety Tips Campaigns SUBSCRIBE Emergencies A-Z Share this! Home » Emergency 101 Heat- ... CPR if the person becomes unconscious. READ IN EMERGENCIES A-Z Teeth (Dental Emergencies) Vomiting and Diarrhea ...

  7. Analytical heat transfer

    Han, Je-Chin


    … it will complete my library … [and] complement the existing literature on heat transfer. It will be of value for both graduate students and faculty members.-Bengt Sunden, Lund University, Sweden

  8. Heat-Related Illnesses

    Full Text Available ... pulse; rapid, shallow breathing; vomiting; and increased body temperature of more than 104 degrees. People with these ... loss of consciousness, vomiting or a high body temperature. For late stage heat stroke symptoms, cool the ...

  9. Heating of toroidal plasmas

    The limitations of ohmic heating in achieving the thermonuclear ignition of a low-β toroidal plasma can be overcome by using several heating methods. Such methods are: fast neutral beam injection (possibly combined with an adiabatic compression or any other means) and HF heating, the most interesting schemes being based on plasma resonances. The basic physical phenomena in each method are briefly explained and results obtained are given. A new heating scheme using an outer frequency of a few kHz is described, that makes it possible to locate the exciting coils outside the vacuum vessel (some of these coils can be that producing the vertical magnetic field for the plasma equilibrium)

  10. Policies for Renewable Heat



    This paper builds on IEA publications, Deploying Renewables, Principles for Effective Policies and Deploying Renewables, Best and Future Policy Practice, that discuss the 'integrated policy approach,' whereby renewable energy technologies require different support policies at different stages of their maturity pathways. The paper discusses how the integrated policy approach applies to renewable heat. It attempts to provide guidance for policy-makers on renewable heat throughout the different phases of the policy lifecycle, allowing for the specific challenges of renewable heat and needs of the many stakeholders involved. Stimulating a market for heat involves challenges that are different and, often, more difficult to overcome than in the electricity and transport sectors.

  11. Heat-Related Illnesses

    Full Text Available ... exhaustion symptoms include cool, moist, pale or flushed skin; headache; dizziness; weakness; feeling exhausted; heavy sweating; nausea; ... stage of heat illness) include flushed, hot, dry skin; fainting; a rapid, weak pulse; rapid, shallow breathing; ...

  12. Geodesics in Heat

    Crane, Keenan; Weischedel, Clarisse; Wardetzky, Max


    We introduce the heat method for computing the shortest geodesic distance to a specified subset (e.g., point or curve) of a given domain. The heat method is robust, efficient, and simple to implement since it is based on solving a pair of standard linear elliptic problems. The method represents a significant breakthrough in the practical computation of distance on a wide variety of geometric domains, since the resulting linear systems can be prefactored once and subsequently solved in near-li...

  13. Heat Switches for ADRs

    DiPirro, M. J.; Shirron, P. J.


    Heat switches are key elements in the cyclic operation of Adiabatic Demagnetization Refrigerators (ADRs). Several of the types of heat switches that have been used for ADRs are described in this paper. Key elements in selection and design of these switches include not only ON/OFF switching ratio, but also method of actuation, size, weight, and structural soundness. Some of the trade-off are detailed in this paper.

  14. Thermal radiation heat transfer

    Howell, John R; Siegel, Robert


    Further expanding on the changes made to the fifth edition, Thermal Radiation Heat Transfer, 6th Edition continues to highlight the relevance of thermal radiative transfer and focus on concepts that develop the radiative transfer equation (RTE). The book explains the fundamentals of radiative transfer, introduces the energy and radiative transfer equations, covers a variety of approaches used to gauge radiative heat exchange between different surfaces and structures, and provides solution techniques for solving the RTE.

  15. Superradiant Quantum Heat Engine

    Hardal, Ali Ü. C.; Müstecaplıoğlu, Özgür E.


    Scientific Reports | 5:12953 | DOI: 10.1038/srep12953 1 Superradiant Quantum Heat Engine Ali Ü. C. Hardal & Özgür E. Müstecaplıoğlu Quantum physics revolutionized classical disciplines of mechanics, statistical physics, and electrodynamics. One branch of scientific knowledge however seems untouched: thermodynamics. Major motivation behind thermodynamics is to develop eficient heat engines. Technology has a trend to miniaturize engines, ...

  16. Conducting the Heat


    Heat conduction plays an important role in the efficiency and life span of electronic components. To keep electronic components running efficiently and at a proper temperature, thermal management systems transfer heat generated from the components to thermal surfaces such as heat sinks, heat pipes, radiators, or heat spreaders. Thermal surfaces absorb the heat from the electrical components and dissipate it into the environment, preventing overheating. To ensure the best contact between electrical components and thermal surfaces, thermal interface materials are applied. In addition to having high conductivity, ideal thermal interface materials should be compliant to conform to the components, increasing the surface contact. While many different types of interface materials exist for varying purposes, Energy Science Laboratories, Inc. (ESLI), of San Diego, California, proposed using carbon velvets as thermal interface materials for general aerospace and electronics applications. NASA s Johnson Space Center granted ESLI a Small Business Innovation Research (SBIR) contract to develop thermal interface materials that are lightweight and compliant, and demonstrate high thermal conductance even for nonflat surfaces. Through Phase II SBIR work, ESLI created Vel-Therm for the commercial market. Vel-Therm is a soft, carbon fiber velvet consisting of numerous high thermal conductivity carbon fibers anchored in a thin layer of adhesive. The velvets are fabricated by precision cutting continuous carbon fiber tows and electrostatically flocking the fibers into uncured adhesive, using proprietary techniques.

  17. Optimal design of the separate type heat pipe heat exchanger

    YU Zi-tao; HU Ya-cai; CEN Ke-fa


    Separate type heat pipe heat exchangers are often used for large-scale heat exchanging. The arrangement of such a heat exchanger conveniently allows heat input to and output from the heat exchanger at remote locations. The traditional method of designing an ordinary HPHE (heat pipe heat exchanger) is commonly applied in the separate type exchanger design, but the calculations have to be carried out separately, which makes it very complicated. In this work, the ε-NTU (effectiveness-Number of Transfer Units) method was applied for optimization analysis of single- or multi-level separate type heat pipe heat exchangers. An optimizing formula for single-level separate type heat pipe heat exchangers was obtained. The optimizing principles of effectiveness-NTU and heat transfer rate by the equal distribution method for multi-level separate type heat pipe heat exchanger are presented. The design of separate type heat pipe heat exchangers by the optimizing method is more convenient and faster than by the traditional method.


    Podobeková, Veronika; Peráčková, Jana


    The article discusses utilization of heat from waste water in sewage. During the year, temperature of water in sewage ranges between 10 °C and 20 °C and the heat from sewage could be used for heating, cooling and hot water preparation in building. The heat is extracted through a transfer surface area of the heat exchanger into the heat pump, which is able to utilize the low–potential energy. Different design and types of the heat exchangers in sewage are dealt with: heat exchangers embedded i...

  19. VII international district heating conference

    The proceedings of the 7th International District Heating Conference contain the full texts of the 89 presented papers of which 11 fall under the INIS Subject Scope. The conference met in seven sessions and dealt with the following problem areas: design and optimization of systems of district heating, integration of the power system and the district heating systems, cooperation of nuclear and fossil burning sources in district heating systems, the use of specific nuclear power plants for heating purposes, questions of the control of systems of district heating, the development of components of heating networks, the reliability and design of heat supply pipes. (Z.M.)

  20. Utilization of heat pipes for transfer heat from the flue gas into the heat transfer medium

    Lenhard Richard


    Full Text Available The contribution is listed possible application of heat pipes in systems for obtaining heat from flue gas of small heat sources. It is also stated in the contribution design an experimental device on which to study the impact of fill (the quantity, type of load at various temperature parameters (temperature heating and cooling thermal power transferred to the heat pipe. Is listed measurement methodology using heat pipes designed experimental facility, measurement results and analysis of the results obtained.

  1. Numerical research of heat transfer in gas heat exchanger

    Khomutov Eugene O.; Gil Andrey V.


    The article presents a numerical study of heat and mass transfer based on the finite volume method. Researched by installing a tubular heat exchanger for heating of natural gas. The results according to changes in temperature of the natural gas depend on the initial temperature of the heating flow. The results can be used in the analysis of further effective combustion.

  2. Heat exchanger device and method for heat removal or transfer

    Koplow, Jeffrey P


    Systems and methods for a forced-convection heat exchanger are provided. In one embodiment, heat is transferred to or from a thermal load in thermal contact with a heat conducting structure, across a narrow air gap, to a rotating heat transfer structure immersed in a surrounding medium such as air.

  3. Heat Pump with Two Heat Sources on Different Temperature Levels

    Bertsch, Stefan; Uhlmann, Michael; Heldstab, Andres


    Aim of the project is the development of a new heat pump system with economizing that is able to improve the heating performance using two or more different heat sources. These heat sources preferably on different temperature levels are incorporated in the system with minimal loss of exergy, by adding the heat at different pressure levels. Applications are i.e. buildings with heat pump and a solar thermal collector. While solar thermal systems can be used for heating and domestic hot water in...

  4. Heat exchanger restart evaluation

    Morrison, J.M.; Hirst, C.W.; Lentz, T.F.


    On December 24, 1991, the K-Reactor was in the shutdown mode with full AC process water flow and full cooling water flow. Safety rod testing was being performed as part of the power ascension testing program. The results of cooling water samples indicated tritium concentrations higher than allowable. Further sampling and testing confirmed a Process Water System to Cooling Water System leak in heat exchanger 4A (HX 4A). The heat exchanger was isolated and the plant shutdown. Heat exchanger 4A was removed from the plant and moved to C-Area prior to performing examinations and diagnostic testing. This included locating and identifying the leaking tube or tubes, eddy current examination of the leaking tube and a number of adjacent tubes, visually inspecting the leaking tube from both the inside as well as the area surrounding the identified tube. The leaking tube was removed and examined metallurgically to determine the failure mechanism. In addition ten other tubes that either exhibited eddy current indications or would represent a baseline condition were removed from heat exchanger 4A for metallurgical examination. Additional analysis and review of heat exchanger leakage history was performed to determine if there are any patterns which can be used for predictive purposes. Compensatory actions have been taken to improve the sensitivity and response time to any future events of this type. The results of these actions are summary herein.

  5. Heat exchanger restart evaluation

    Morrison, J.M.; Hirst, C.W.; Lentz, T.F.


    On December 24, 1991, the K-Reactor was in the shutdown mode with full AC process water flow and full cooling water flow. Safety rod testing was being performed as part of the power ascension testing program. The results of cooling water samples indicated tritium concentrations higher than allowable. Further sampling and testing confirmed a Process Water System to Cooling Water System leak in heat exchanger 4A (HX 4A). The heat exchanger was isolated and the plant shutdown. Heat exchanger 4A was removed from the plant and moved to C-Area prior to performing examinations and diagnostic testing. This included locating and identifying the leaking tube or tubes, eddy current examination of the leaking tube and a number of adjacent tubes, visually inspecting the leaking tube from both the inside as well as the area surrounding the identified tube. The leaking tube was removed and examined metallurgically to determine the failure mechanism. In addition ten other tubes that either exhibited eddy current indications or would represent a baseline condition were removed from heat exchanger 4A for metallurgical examination. Additional analysis and review of heat exchanger leakage history was performed to determine if there are any patterns which can be used for predictive purposes. Compensatory actions have been taken to improve the sensitivity and response time to any future events of this type. The results of these actions are summarized.

  6. Heat exchanger restart evaluation

    On December 24, 1991, the K-Reactor was in the shutdown mode with full AC process water flow and full cooling water flow. Safety rod testing was being performed as part of the power ascension testing program. The results of cooling water samples indicated tritium concentrations higher than allowable. Further sampling and testing confirmed a Process Water System to Cooling Water System leak in heat exchanger 4A (HX 4A). The heat exchanger was isolated and the plant shutdown. Heat exchanger 4A was removed from the plant and moved to C-Area prior to performing examinations and diagnostic testing. This included locating and identifying the leaking tube or tubes, eddy current examination of the leaking tube and a number of adjacent tubes, visually inspecting the leaking tube from both the inside as well as the area surrounding the identified tube. The leaking tube was removed and examined metallurgically to determine the failure mechanism. In addition ten other tubes that either exhibited eddy current indications or would represent a baseline condition were removed from heat exchanger 4A for metallurgical examination. Additional analysis and review of heat exchanger leakage history was performed to determine if there are any patterns which can be used for predictive purposes. Compensatory actions have been taken to improve the sensitivity and response time to any future events of this type. The results of these actions are summarized

  7. Heat Conduction in Lenses

    Beat Aebischer


    Full Text Available We consider several heat conduction problems for glass lenses with different boundary conditions. The problems dealt with in Sections sec:1 to sec:3 are motivated by the problem of an airborne digital camera that is initially too cold and must be heated up to reach the required image quality. The problem is how to distribute the heat to the different lenses in the system in order to reach acceptable operating conditions as quickly as possible. The problem of Section sec:4 concerns a space borne laser altimeter for planetary exploration. Will a coating used to absorb unwanted parts of the solar spectrum lead to unacceptable heating? In this paper, we present analytic solutions for idealized cases that help in understanding the essence of the problems qualitatively and quantitatively, without having to resort to finite element computations. The use of dimensionless quantities greatly simplifies the picture by reducing the number of relevant parameters. The methods used are classical: elementary real analysis and special functions. However, the boundary conditions dictated by our applications are not usually considered in classical works on the heat equation, so that the analytic solutions given here seem to be new. We will also show how energy conservation leads to interesting sum formulae in connection with Bessel functions. The other side of the story, to determine the deterioration of image quality by given (inhomogeneous temperature distributions in the optical system, is not dealt with here.

  8. Ground Source Heat Pump in Heating System with Electronics Monitoring

    NEAMŢU Ovidiu


    Full Text Available The monitoring system is implemented for a ground coupled heat pump in heating/ system. The borehole heat exchangers – which are 150 m long - are filled with a mixture of water and ethilene glycol calledbrine. Metering and monitoring energy consumption is achieved for: heat pump, circulation pumps, additional electrical heating, hot air ventilation systems, control systems with sensors: analog and smart sensors. Instantaneous values are stored in a local computer.

  9. Optimum geometry of MEMS heat exchanger for heat transfer enhancement

    Nusrat J. Chhanda; Muhannad Mustafa; Maglub Al Nur


    The study is based on an analysis of MEMS heat exchanger of three different geometries: wavy, triangular and rectangular using water as test fluid. The problem is solved using finite element method. The aim of this analysis is to evaluate the performance of MEMS heat exchanger for different geometry and to obtain an optimum design for better heat enhancement. It is apparent from this work that rectangular surface heat exchanger shows the best performance for heat enhancement technique in comp...

  10. Optimization of heat exchanger for indirectly heated water heater

    Kaduchová Katarína; Lenhard Richard; Jandačka Jozef


    Due to the optimization of geometrical parameters of the heat exchanger in indirect heated water heaters created a mathematical model of heating hot water, by which I have subsequently made the simulation of the device to change its geometrical parameters. Based on these results, the impacts of the geometrical parameters affect the performance of the heat exchanger. The results of the optimization to create a CFD model which watched at the behavior of optimized heat exchanger for indirect hea...

  11. Fault-Tolerant Heat Exchanger

    Izenson, Michael G.; Crowley, Christopher J.


    A compact, lightweight heat exchanger has been designed to be fault-tolerant in the sense that a single-point leak would not cause mixing of heat-transfer fluids. This particular heat exchanger is intended to be part of the temperature-regulation system for habitable modules of the International Space Station and to function with water and ammonia as the heat-transfer fluids. The basic fault-tolerant design is adaptable to other heat-transfer fluids and heat exchangers for applications in which mixing of heat-transfer fluids would pose toxic, explosive, or other hazards: Examples could include fuel/air heat exchangers for thermal management on aircraft, process heat exchangers in the cryogenic industry, and heat exchangers used in chemical processing. The reason this heat exchanger can tolerate a single-point leak is that the heat-transfer fluids are everywhere separated by a vented volume and at least two seals. The combination of fault tolerance, compactness, and light weight is implemented in a unique heat-exchanger core configuration: Each fluid passage is entirely surrounded by a vented region bridged by solid structures through which heat is conducted between the fluids. Precise, proprietary fabrication techniques make it possible to manufacture the vented regions and heat-conducting structures with very small dimensions to obtain a very large coefficient of heat transfer between the two fluids. A large heat-transfer coefficient favors compact design by making it possible to use a relatively small core for a given heat-transfer rate. Calculations and experiments have shown that in most respects, the fault-tolerant heat exchanger can be expected to equal or exceed the performance of the non-fault-tolerant heat exchanger that it is intended to supplant (see table). The only significant disadvantages are a slight weight penalty and a small decrease in the mass-specific heat transfer.

  12. Heat Pipe Blocks Return Flow

    Eninger, J. E.


    Metal-foil reed valve in conventional slab-wick heat pipe limits heat flow to one direction only. With sink warmer than source, reed is forced closed and fluid returns to source side through annular transfer wick. When this occurs, wick slab on sink side of valve dries out and heat pipe ceases to conduct heat.

  13. Fluctuation Relation for Heat Engines

    Sinitsyn, N. A.


    We derive the exact equality, referred to as the fluctuation relation for heat engines (FRHE), that relates statistics of heat extracted from one of the two heat baths and the work per one cycle of a heat engine operation. Carnot's inequality of classical thermodynamics follows as a direct consequence of the FRHE.

  14. Determination of plasma heat conductivity

    The problem of determination of plasma electron heat conductivity is considered. The similar approach can be used to determine the coefficients of ion heat conductivity or diffusion. Generally it can be used to find the coefficient of heat conductivity (diffusion) in all the cases, where the concept of a continuous medium and a heat transfer model can be applied

  15. Structures to radiate heat softly

    Perilae, T.; Wikstroem, T. [ed.


    Over the past fifty years, heating systems in single-family houses have taken a great leap forward. First wood-burning stoves gave way to oil heaters; then these were superseded by central heating systems; and now conventional central heating systems have lost their way with the increasingly widespread use of room-specific heating systems

  16. Experiments Demonstrate Geothermal Heating Process

    Roman, Harry T.


    When engineers design heat-pump-based geothermal heating systems for homes and other buildings, they can use coil loops buried around the perimeter of the structure to gather low-grade heat from the earth. As an alternative approach, they can drill well casings and store the summer's heat deep in the earth, then bring it back in the winter to warm…

  17. Performance of heat pumps with direct expansion in vertical ground heat exchangers in heating mode

    Highlights: • The work focuses on direct expansion ground source heat pumps in heating mode. • The evaporating process of the refrigerant fluid into boreholes is analyzed. • A method to design the direct expansion borehole heat exchangers is presented. • Direct expansion and the common secondary loop heat pumps are compared. • The comparison is carried out in terms of both borehole length and performance. - Abstract: Ground source heat pump systems represent an interesting example of renewable energy technology for heating and cooling of buildings. The connection with the ground is usually done by means of a closed loop where a heat-carrier fluid (pure water or a solution of antifreeze and water) flows and, in heating mode, moves heat from ground to refrigerant fluid of heat pump. A new solution is the direct expansion heat pump. In this case, the heat-carrier fluid inside the ground loop is the same refrigerant fluid of heat pump. This paper focuses on the energy performance of direct expansion ground source heat pump with borehole heat exchangers in heating mode, looking at residential building installations. For this purpose, the evaporating process of the refrigerant fluid inside vertical tubes is investigated in order to analyze the influence of the convective heat transfer coefficient on the global heat transfer with the surrounding ground. Then, an analytical model reported in literature for the design of common borehole heat exchangers has been modified for direct expansion systems. Finally, the direct expansion and common ground source heat pumps have been compared in terms of both total borehole length and thermal performance. Results indicate that the direct expansion system has higher energy performance and requires lower total borehole length compared to the common system. However, when the two systems are compared with the same mean fluid evaporating temperature, the overall length of the ground heat exchanger of the direct expansion heat

  18. District heating in Flensburg

    Prinz, W.


    The majority of our population, but also of our authorities, are still skeptical or even disapproving towards district heating. The reasons of this negative attitude are partly psychological - e.g. the individualism of the Swiss and their dislike for too centralised structures and ''forced connections'' - but also the existence of finished gas supply networks and the fear of considerable pre-investments and torn streets over years. The following article - held as a speech on the information meeting ''District heating and the possible contribution of nuclear energy'' organised by the Swiss Association for Atomic Energy in Bern shows a practical problem solving at the example of the district heating in Flensburg and deals with these questions.

  19. Ventilation with heat recovery

    Tommerup, Henrik M.; Svendsen, Svend


    This paper presents the experiences from the use of ventilation with heat recovery in several experimental single-family houses developed and built within the last four years to meet the new Danish energy requirements of 2005. Included are descriptions of the ventilation system components...... and the main functional demands as well as measurements of the thermal efficiency, electricity consumptions and building air tightness. The paper addresses the aspects of minimizing the heat loss from the duct system and the heat recovery unit (when placed in an unheated attic space) in order to obtain...... an acceptable efficiency. Furthermore, solutions to secure the air tightness of the building envelope are suggested. The paper does not address problems with condensate of water in the exchanger that may freeze in cold climate conditions. This complex of problem is dealt with in a separate paper....

  20. Elements of heat transfer

    Rathakrishnan, Ethirajan


    1 Basic Concepts and Definitions1.1 Introduction1.1.1 Driving Potential1.2 Dimensions and Units1.2.1 Dimensional Homogeneity1.3 Closed and Open Systems1.3.1 Closed System (ControlMass)1.3.2 Isolated System1.3.3 Open System (ControlVolume)1.4 Forms of Energy1.4.1 Internal Energy1.5 Properties of a System1.5.1 Intensive and Extensive Properties1.6 State and Equilibrium1.7 Thermal and Calorical Properties1.7.1 Specific Heat of an Incompressible Substance1.7.2 Thermally Perfect Gas 1.8 The Perfect Gas1.9 Summary1.10 Exercise ProblemsConduction Heat Transfer2.1 Introduction2.2 Conduction Heat Trans

  1. Heat and mass transfer

    Baehr, Hans Dieter


    This comprehensive textbook provides a solid foundation of knowledge on the principles of heat and mass transfer and shows how to solve problems by applying modern methods. The basic theory is developed systematically, exploring in detail the solution methods to all important problems.   The thoroughly revised 3rd edition includes an introduction to the numerical solution of Finite Elements. A new section on heat and mass transfer in porous media has also been added.   The book will be useful not only to upper-level and graduate students, but also to practicing scientists and engineers, offering a firm understanding of the principles of heat and mass transfer, and showing how to solve problems by applying modern methods. Many completed examples and numerous exercises with solutions facilitate learning and understanding, and an appendix includes data on key properties of important substances.

  2. Microgravity condensing heat exchanger

    Thomas, Christopher M. (Inventor); Ma, Yonghui (Inventor); North, Andrew (Inventor); Weislogel, Mark M. (Inventor)


    A heat exchanger having a plurality of heat exchanging aluminum fins with hydrophilic condensing surfaces which are stacked and clamped between two cold plates. The cold plates are aligned radially along a plane extending through the axis of a cylindrical duct and hold the stacked and clamped portions of the heat exchanging fins along the axis of the cylindrical duct. The fins extend outwardly from the clamped portions along approximately radial planes. The spacing between fins is symmetric about the cold plates, and are somewhat more closely spaced as the angle they make with the cold plates approaches Passageways extend through the fins between vertex spaces which provide capillary storage and communicate with passageways formed in the stacked and clamped portions of the fins, which communicate with water drains connected to a pump externally to the duct. Water with no entrained air is drawn from the capillary spaces.

  3. Large Scale Solar Heating

    Heller, Alfred


    The main objective of the research was to evaluate large-scale solar heating connected to district heating (CSDHP), to build up a simulation tool and to demonstrate the application of the simulation tool for design studies and on a local energy planning case. The evaluation was mainly carried out...... model is designed and validated on the Marstal case. Applying the Danish Reference Year, a design tool is presented. The simulation tool is used for proposals for application of alternative designs, including high-performance solar collector types (trough solar collectors, vaccum pipe collectors......). Simulation programs are proposed as control supporting tool for daily operation and performance prediction of central solar heating plants. Finaly the CSHP technolgy is put into persepctive with respect to alternatives and a short discussion on the barries and breakthrough of the technology are given....

  4. Thermal radiation heat transfer

    Howell, John R; Mengüç, M Pinar


    Providing a comprehensive overview of the radiative behavior and properties of materials, the fifth edition of this classic textbook describes the physics of radiative heat transfer, development of relevant analysis methods, and associated mathematical and numerical techniques. Retaining the salient features and fundamental coverage that have made it popular, Thermal Radiation Heat Transfer, Fifth Edition has been carefully streamlined to omit superfluous material, yet enhanced to update information with extensive references. Includes four new chapters on Inverse Methods, Electromagnetic Theory, Scattering and Absorption by Particles, and Near-Field Radiative Transfer Keeping pace with significant developments, this book begins by addressing the radiative properties of blackbody and opaque materials, and how they are predicted using electromagnetic theory and obtained through measurements. It discusses radiative exchange in enclosures without any radiating medium between the surfaces-and where heat conduction...

  5. Heat transfer fluids containing nanoparticles

    Singh, Dileep; Routbort, Jules; Routbort, A.J.; Yu, Wenhua; Timofeeva, Elena; Smith, David S.; France, David M.


    A nanofluid of a base heat transfer fluid and a plurality of ceramic nanoparticles suspended throughout the base heat transfer fluid applicable to commercial and industrial heat transfer applications. The nanofluid is stable, non-reactive and exhibits enhanced heat transfer properties relative to the base heat transfer fluid, with only minimal increases in pumping power required relative to the base heat transfer fluid. In a particular embodiment, the plurality of ceramic nanoparticles comprise silicon carbide and the base heat transfer fluid comprises water and water and ethylene glycol mixtures.

  6. Intensification of Convective Heat Transfer in Heating Device of Mobile Heating System with BH-Heat Generator

    N. Nesenchuk


    Full Text Available Directions pertaining to intensification of convective heat transfer in a soft heating device have been experimentally investigated  in the paper and the most efficient one has been selected that is creation of artificial roughness on the device surface. The considered heating device for a heat supply system of a mobile object has been made of soft polymer material (polyvinyl chloride. Following  evaluation results of  heat exchange intensification a criteria equation has been obtained for calculation of external heat transfer with due account of heat transfer intensification.

  7. Heat transfer studies

    Drying in subresidually-saturated systems at elevated temperatures has been studied for two different operating conditions. One condition started with flowing nitrogen gas through the test section and simultaneously heating up the porous medium at the same time (denoted in what follows as the ''transient heating case''). The other condition started initially with heating up the porous medium with no flow, and then running the nitrogen gas flow through the test section after a steady-state temperature distribution had been reached (denoted in what follows as the ''steady heating case''). A 90 degrees C isothermal boundary condition was set on the aluminum wall. An average of 9% discrepancy in the mass balance calculation compared to the digital balance measurement has been found in the transient heating case. An average of 4.3% discrepancy in the mass balance calculation compared to the digital balance measurement has been found after the nitrogen gas flowed through test section for the steady heating case. A large discrepancy has also been found before the nitrogen gas admitted to the test section. This is because some of subresidual water in the test section has been drained out from the bottom due to the gravity effect and the strong convection flow in the porous medium before the nitrogen gas is admitted. This discrepancy may be reduced by closing the end tube at bottom before the nitrogen gas is admitted to the test section. The drying characteristics of this system are reported. A theoretical study has also been initiated in an attempt to supplement the experimental results, and this system is described in the report. A one-dimensional transient system is assumed in which a two-component (condensable and noncondensable) gas mixture flows through a porous medium with evaporation. The numerical calculation will be performed in the future work to compare to the experimental results

  8. Ceramic heat recuperators for industrial heat recovery

    Cleveland, J. J.; Gonzalez, J. M.; Kohnken, K. H.; Rebello, W. J.


    A cordierite (magnesium aluminum silicate) recuperator was designed for relatively small furnaces with firing rates of 0.3 MM to 0.6 MM Btu/h and with exhaust gas temperatures of 1500 F to 2600 F. Five demonstration programs were performed to determine the heat transfer performance of the device, establish the energy savings by recovery, demonstrate the durability of the ceramic core, determine the operating requirements of the burners and controls with recuperation, and establish the overall system costs and payback period. The recuperator is described and results of tests and measurements, system economics, and cost performance analyses are presented. The methodology is developed and techniques for impact analysis are described. Industrial applications are implied and a process flow diagram for smelting and refining primary copper is shown.

  9. Convective Heat Transfer

    Favre-Marinet, Michel


    Convection heat transfer is an important topic both for industrial applications and fundamental aspects. It combines the complexity of the flow dynamics and of the active or passive scalar transport process. It is part of many university courses such as Mechanical, Aeronautical, Chemical and Biomechanical Engineering. The literature on convective heat transfer is large, but the present manuscript differs in many aspects from the existing ones, particularly from the pedagogical point of view. Each chapter begins with a brief yet complete presentation of the related topic. This is followed by a

  10. A heat transfer textbook

    Lienhard, John H


    This introduction to heat transfer offers advanced undergraduate and graduate engineering students a solid foundation in the subjects of conduction, convection, radiation, and phase-change, in addition to the related topic of mass transfer. A staple of engineering courses around the world for more than three decades, it has been revised and updated regularly by the authors, a pair of recognized experts in the field. The text addresses the implications, limitations, and meanings of many aspects of heat transfer, connecting the subject to its real-world applications and developing students' ins

  11. Solar industrial process heat

    Lumsdaine, E.


    The aim of the assessment reported is to candidly examine the contribution that solar industrial process heat (SIPH) is realistically able to make in the near and long-term energy futures of the United States. The performance history of government and privately funded SIPH demonstration programs, 15 of which are briefly summarized, and the present status of SIPH technology are discussed. The technical and performance characteristics of solar industrial process heat plants and equipment are reviewed, as well as evaluating how the operating experience of over a dozen SIPH demonstration projects is influencing institutional acceptance and economoc projections. Implications for domestic energy policy and international implications are briefly discussed. (LEW)

  12. [Pathophysiology of heat illness].

    Aruga, Tohru; Miyake, Yasufumi


    Human core temperature is strictly controlled by mechanism of radiation, conduction, convection, and evaporation from skin surface. Serial hot and humid climate induces dehydration which interferes heat pump-out from the body. Heart dysfunction is the third factor to rise body temperature. Hyperthermia and hypo-perfusion caused by dehydration and heart failure deteriorate specific organ functions, i.e. central nervous system, liver and renal functions and coagulation system. Disseminated intravascular coagulopathy is one of the standard indicators of severity and mortality of heat stroke. PMID:22690597

  13. Adaptive heat engine

    Allahverdyan, A.E.; Babajanyan, S. G.; Martirosyan, N. H.; Melkikh, A. V.


    A major limitations for many heat engines is that their functioning demands on-line control, and/or an external fitting between environmental parameters (e.g. temperatures of thermal baths) and internal parameters of the engine. We study a model for an adaptive heat engine, where---due to feedback from the functional part---the engine's structure adapts to given thermal baths. Hence no on-line control and no external fitting are needed. The engine can employ unknown resources, it can also ada...

  14. Harnessing solar heat

    Norton, Brian


    Systems engineered by man to harness solar heat in a controlled manner now include a diverse range of technologies each serving distinctive needs in particular climate contexts. This text covers the breadth of solar energy technologies for the conversion of solar energy to provide heat, either as the directly-used output or as an intermediary to other uses such as power generation or cooling. It is a wholly updated, extended and revised version of “Solar Energy Thermal Technology” first published in 1992. The text draws on the own author’s research and that of numerous colleagues and

  15. Alfven wave heating

    The physics of Alfven-wave heating is particularly sensitive to the character of the linear mode conversion which occurs at the Alfven resonance layer. Parameter changes can profoundly affect both the location within the plasma and the mechanism for the power absorption. Under optimal conditions the heating power may be absorbed by electron Landau damping and by electron transit-time magnetic pumping in the plasma interior, or by the same processes acting near the resonance layer on the mode-converted kinetic Alfven wave. The method is outlined for computing the coefficients for reflection, transmission and absorption at the resonance layer and some representative results are offered

  16. Heat exchanger panel

    Warburton, Robert E. (Inventor); Cuva, William J. (Inventor)


    The present invention relates to a heat exchanger panel which has broad utility in high temperature environments. The heat exchanger panel has a first panel, a second panel, and at least one fluid containment device positioned intermediate the first and second panels. At least one of the first panel and the second panel have at least one feature on an interior surface to accommodate the at least one fluid containment device. In a preferred embodiment, each of the first and second panels is formed from a high conductivity, high temperature composite material. Also, in a preferred embodiment, the first and second panels are joined together by one or more composite fasteners.

  17. Geothermal heating saves energy

    The article reviews briefly a pioneer project for a construction area of 200000 m''2 with residences, business complexes, a hotel and conference centre and a commercial college in Oslo. The energy conservation potential is estimated to be about 60-70 % compared to direct heating with oil, gas or electricity as sources. There will also be substantial reduction in environmentally damaging emissions. The proposed energy central combines geothermal energy sources with heat pump technology, utilises water as energy carrier and uses terrestrial wells for energy storage. A cost approximation is presented

  18. Heat exposure effects among firefighters

    Patel Harshad; Rao Nellore; Saha Asim


    Background: Firefighting is a hazardous occupation. The firefighters (FF) in extinguishing fire are often exposed to extreme heat of 1200oC to 1400oC temperature. The heat exposure effects may occur from hot air, radiant heat, contact with hot surfaces, endogenous heat produced by the body during exercise, which cannot be cooled during fire. A significant morbidity and mortality from exposure to heat was reported in other countries but not from India. Aims : Present study focuses on prevale...


    A. I. Kolosov


    Full Text Available Problem statement. The paper discusses the problem of estimation of prospects of heat accumulation in the combined systems of heat supply with the use of low potential energy of renewable sources (sun and ground and heat pumps for increase of their potential.Results and conclusions. The use of heat accumulators in combined heating systems that utilize low-potential solar and ground energy as primary energy sources and heat pumps to boost the po-tential of the latter was discussed. A method of calculating ground heat exchangers that use the heat pump cycle to increase a thermal potential of renewable energy sources was set forth. An at-tempt was made at addressing the problem of heat and mass transfer in ground when ground ac-cumulators like “a Field’s tube” are used: a geothermal circulation system comprises two wells (pumping and operational.

  20. Spatial Heat Planning and Heat Demand Reductions in Buildings

    Nielsen, Steffen; Møller, Bernd; Lund, Henrik


    long-term savings in investments in production capacity and fuel costs. Through a case study, the amount of these long-term sav-ings is compared to the costs of implementing heat savings. The case study shows that heat reductions of roughly 50% are feasible if the long-term costs are included. Savings...... on the heat supply in Denmark. Even though the focus is on Denmark, the methods and results are applicable to other places as well, as they build on assumptions that are also present in other countries. In Denmark approximately half of the heat demand is sup-plied by district heating, and half of the district...... heating already uses renew-able energy. Within densely built-up areas district heating systems are re-source effective compared to individual solutions as district heating sys-tems can use excess heat from power plants, industries, and waste incin-eration as well as renewable energy, like geothermal...

  1. Primary energy savings using heat storage for biomass heating systems

    Mitrović Dejan M.


    Full Text Available District heating is an efficient way to provide heat to residential, tertiary and industrial users. The heat storage unit is an insulated water tank that absorbs surplus heat from the boiler. The stored heat in the heat storage unit makes it possible to heat even when the boiler is not working, thus increasing the heating efficiency. In order to save primary energy (fuel, the boiler operates on nominal load every time it is in operation (for the purpose of this research. The aim of this paper is to analyze the water temperature variation in the heat storage, depending on the heat load and the heat storage volume. Heat load is calculated for three reference days, with average daily temperatures from -5 to 5°C. The primary energy savings are also calculated for those days in the case of using heat storage in district heating.[Projekat Ministarstva nauke Republike Srbije, br. TR 33051: The concept of sustainable energy supply of settlements with energy efficient buildings

  2. Waste heat of HTR power stations for district heating

    The market situation, the applied techniques, and the transport, for district heating in combination with HTR plants are considered. Analysis of the heat market indicates a high demand for heat at temperatures between 100 and 1500C in household and industry. This market for district heating can be supplied by heat generated in HTR plants using two methods: (1) the combined heat and power generation in steam cycle plants by extracting steam from the turbine, and (2) the use of waste heat of a closed gas turbine cycle. The heat generation costs of (2) are negligible. The cost for transportation of heat over the average distance between existing plant sites and consumer regions (25 km) are between 10 and 20% of the total heat price, considering the high heat output of nuclear power stations. Comparing the price of heat gained by use of waste heat in HTR plants with that of conventional methods, considerable advantages are indicated for the combined heat and power generation in HTR plants. (author)

  3. Flow boiling heat transfer in volumetrically heated packed bed

    Highlights: • The onset of nucleate boiling in the volumetrically heated packed bed is researched. • A correlation for predicting qONB is developed. • The effects on boiling heat transfer coefficient are investigated. - Abstract: The volumetrically heated packed bed has been widely utilized in modern industry. However, due to the variability and randomness of packed bed channels, flow boiling heat transfer characteristics becomes complex, and there are no published research regarding this topic. To study flow boiling heat transfer characteristics of volumetrically heated packed beds, electromagnetic induction heating method is used to heat oxidized carbon steel balls adopted to stack the packed bed, with water as coolant in the experiment. The experimental results indicate that heat flux at onset of nucleate boiling (ONB) increases as mass flux and inlet subcooling are increased. A new correlation is developed to predict the ONB heat flux qONB in volumetrically heated packed bed, the predictions by which agree well with the experimental data, and the deviation remains less than 15%. Subcooled flow boiling heat transfer coefficient (hsub) increases with increasing mass flux, and equilibrium quality is slightly affected by heat flux. The saturated flow boiling heat transfer coefficient (hsat) increases with mass flux and equilibrium quality when equilibrium quality is lower than about 0.05, while the nucleate boiling is suppressed when the equilibrium quality exceeds a certain value

  4. Heat Transfer Characteristics of SiC-coated Heat Pipe for Passive Decay Heat Removal

    Kim, Kyung Mo; Kim, In Guk; Jeong, Yeong Shin; Bang, In Cheol [Ulsan National Institute of Science and Technology, Ulsan (Korea, Republic of)


    The main concern with the Fukushima accident was the failure of active and passive core cooling systems. The main function of existing passive decay heat removal systems is feeding additional coolant to the reactor core. Thus, an established emergency core cooling system (ECCS) cannot operate properly because of impossible depressurization under the station blackout (SBO) condition. Therefore, a new concept for passive decay heat removal system is required. In this study, an innovative hybrid control rod concept is considered for passive in-core decay heat removal that differs from the existing direct vessel injection core cooling system and passive auxiliary feedwater system (PAFS). The heat transfer between the evaporator and condenser sections occurs by phase change of the working fluid and capillary action induced by wick structures installed on the inner wall of the heat pipe. In this study, a hybrid control rod is developed to take the roles of both neutron absorption and heat removal by combining the functions of a heat pipe and control rod. Previous studies on enhancing the heat removal capacity of heat pipes used nanofluids, self-rewetting fluids, various wick structures and condensers. Many studies have examined the thermal performances of heat pipes using various nanofluids. They concluded that the enhanced thermal performance of the heat pipe using nanofluids is due to nanoparticle deposition on the wick structures. Thus, the wick structure of heat pipes has been modified by nanoparticle deposition to enhance the heat removal capacity. However, previous studies used relatively small heat pipes and narrow ranges of heat loads. The environment of a nuclear reactor is very specific, and the decay heat produced by fission products after shutdown is relatively large. Thus, this study tested a large-scale heat pipe over a wide range of power. The concept of a hybrid heat pipe for an advanced in-core decay heat removal system was introduced for complete

  5. Heat exposure effects among firefighters

    Patel Harshad


    Full Text Available Background: Firefighting is a hazardous occupation. The firefighters (FF in extinguishing fire are often exposed to extreme heat of 1200oC to 1400oC temperature. The heat exposure effects may occur from hot air, radiant heat, contact with hot surfaces, endogenous heat produced by the body during exercise, which cannot be cooled during fire. A significant morbidity and mortality from exposure to heat was reported in other countries but not from India. Aims : Present study focuses on prevalence of heat exposure effects i.e., heat exhaustion, heat syncope, heat pyrexia and heat cramps recorded among fire fighters of Ahmedabad fire brigade. Settings: Ahmedabad fire brigade (AFB of Ahmedabad municipal corporation. Design: Cross sectional. Materials and Methods: Present study focuses on prevalence of heat exposure effects i.e., heat exhaustion, heat syncope, heat pyrexia and heat cramps recorded between 262 FF of AFB. This prevalence′s were observed among firemen those directly exposed to heat in combating fire and others (load trucks, pump trucks etc. that assist the firemen. These were seen in different age groups (< 30; 31-45 and> 45 yrs, duration of exposure (< 10; 11-20 and> 21 yrs.The number of accidents associated with heat exposure was analyzed. Statistical Analysis: Prevalence comparison by Chi-square test. Results: The results revealed that a total of 53 (20.0% FF reported health exposure effects and were higher among firemen than other groups. Heat exhaustion 48 (18.3%; heat syncope 11(4.2%; heat pyrexia 11 (4.2% and heat cramps 16(6.1% were reported indicating significant occurrence of heat stress among firefighters. In majority of FF, the frequency of occurrence was observed at only one instance. There were no differences according to age or duration of exposure. Among 53 FF with heat exposure effects, accident were reported in 10 (18.9% suggesting that heat stress may be responsible for this. Conclusion: Overall, Significant occurrence

  6. Solitons and ionospheric heating

    Weatherall, J. C.; Goldman, M. V.; Sheerin, J. P.; Nicholson, D. R.; Payne, G. L.; Hansen, P. J.


    It is noted that for parameters characterizing the Platteville ionospheric heating facility, the Langmuir wave evolution at the exact reflection point of the heater wave involves an oscillating two-stream instability followed by a collisionally damped three-dimensional soliton collapse. The result gives an alternative explanation for certain experimental observations.

  7. Heat exchanger vibration

    The heat exchangers of various types are common items of plant in the generation and transmission of electricity. The amount of attention given to the flow-induced vibrations of heat exchangers by designers is usually related to the operational history of similar items of plant. Consequently, if a particular design procedure yields items of plant which behave in a satisfactory manner during their operational life, there is little incentive to improve or refine the design procedure. On the other hand, failures of heat exchangers clearly indicate deficiencies in the design procedures or in the data available to the designer. When such failures are attributable to flow-induced vibrations, the identification of the mechanisms involved is a prime importance. Ideally, basic research work provides the background understanding and the techniques necessary to be able to identify the important mechanisms. In practice, the investigation of a flow-induced vibration problem may identify the presence of mechanisms but may not be able to quantify their effects adequately. In these circumstances the need for additional work is established and the objectives of the research programme emerge. The purpose of this paper is to outline the background to the current research programme at C.E.R.L. on heat exchanger vibration

  8. Heat loss from Buildings

    Karlsson, Kenneth; Næraa, Rikke


    Determination of heat loss coefficients for buildings in Denmark. The coefficient are determined for 15 building groups and 3 year intervals. They are based on the BBR-registre and assumptions of U-values(W/K*m2)and computed in a simple spreed sheet model.The results are used in the REVEILLE...

  9. Photovoltaic Roof Heat Flux

    Samady, Mezhgan Frishta

    Solar panels were mounted with different designs onto 1:800 scale building models while temperature and radiation were measured. While there have been other studies aimed at finding the optimal angles for solar panels [9], in this study both the angle and the mounting method were tested. The three PV mounting designs that were considered to provide the most insulation to a building's rooftop were flush, offset (control), and angled. The solar panel offset height became a key component for rooftop insulation as well as the performance of the actual solar panel. Experimental results were given to verify the thermal behavior of the heat loads from the different designs of the photovoltaic panel. From the results, the angled PV design needed 16Z more heat extraction than the offset and flush PV design needed 60% more heat extracted than the offset. In addition to the heat transfer analysis, thermal models were performed to incorporate main atmospheric conditions which were based on the effects of PV mounting structure.

  10. Heat Roadmap Europe 2

    Connolly, David; Mathiesen, Brian Vad; Østergaard, Poul Alberg;

    Many strategies have already been proposed for the decarbonisation of the EU energy system by the year 2050. These typically focus on the expansion of renewable energy in the electricity sector and subsequently, electrifying both the heat and transport sectors as much as possible. In these strate...

  11. Solar Energy: Heat Transfer.

    Knapp, Henry H., III

    This module on heat transfer is one of six in a series intended for use as supplements to currently available materials on solar energy and energy conservation. Together with the recommended texts and references (sources are identified), these modules provide an effective introduction to energy conservation and solar energy technologies. The…

  12. Solar Energy: Home Heating.

    Knapp, Henry H., III

    This module on home heating is one of six in a series intended for use as supplements to currently available materials on solar energy and energy conservation. Together with the recommended texts and references (sources are identified), these modules provide an effective introduction to energy conservation and solar energy technologies. The module…

  13. Solar Energy: Heat Storage.

    Knapp, Henry H., III

    This module on heat storage is one of six in a series intended for use as supplements to currently available materials on solar energy and energy conservation. Together with the recommended texts and references (sources are identified), these modules provide an effective introduction to energy conservation and solar energy technologies. The module…

  14. Heat Roadmap Europe 1

    Connolly, David; Mathiesen, Brian Vad; Østergaard, Poul Alberg;


    energy system, district heating will improve the overall efficiency of the energy system, reduce imported fossil fuel consumption, reduce carbon dioxide emissions, reduce the costs of the energy system (by €14 billion/year in 2050), and also creating more jobs in the EU27 since money will be invested in...

  15. Heat-Related Illnesses

    Full Text Available ... Fact Sheet Health & Safety Tips Campaigns SUBSCRIBE Emergencies A-Z Share this! Home » Emergency 101 Heat-Related ... if the person becomes unconscious. READ IN EMERGENCIES A-Z Poisoning Vomiting and Diarrhea Snake Bites Resources ...

  16. Heat-Related Illnesses

    Full Text Available ... Fact Sheet Health & Safety Tips Campaigns SUBSCRIBE Emergencies A-Z Share this! Home » Emergency 101 Heat-Related ... if the person becomes unconscious. READ IN EMERGENCIES A-Z Nosebleeds Shock Poisoning Resources Home Safety Checklist ...

  17. Heat-Related Illnesses

    Full Text Available ... Fact Sheet Health & Safety Tips Campaigns SUBSCRIBE Emergencies A-Z Share this! Home » Emergency 101 Heat-Related Illnesses ... if the person becomes unconscious. READ IN EMERGENCIES A-Z Your Blood Pressure Score is as Important as ...

  18. Heat-Related Illnesses

    Full Text Available ... Fact Sheet Health & Safety Tips Campaigns SUBSCRIBE Emergencies A-Z Share this! Home » Emergency 101 Heat-Related ... if the person becomes unconscious. READ IN EMERGENCIES A-Z Your Blood Pressure Score is as Important ...

  19. Wave and plasma heating

    In the field of wave heating absorption studies of plasma magnetic waves in the theta pinch are extended to axially inhomogeneous waves. In the Plasmaus 4 experiment direct plasma production has been accomplished for overcritical densities and high magnetic fields. The numerical methods developed at IPF for plasma simulation studies have been applied successfully to further problems. (orig./GG)

  20. Heat-Related Illnesses

    Full Text Available ... Fact Sheet Health & Safety Tips Campaigns SUBSCRIBE Emergencies A-Z Share this! Home » Emergency 101 Heat-Related ... if the person becomes unconscious. READ IN EMERGENCIES A-Z Nosebleeds Head Injury Your Blood Pressure Score ...

  1. ICRF heating of FED

    Both 1-D slab and cylindrical models are used to examine second and third harmonic ICRF heating of FED. The slab model, which divides the plasma into 1500 thin uniform slabs, uses a full-wave treatment to examine the effects of mode conversion. The RF power profile and the amount of energy absorbed per radial pass are also calculated. The 1-D cylindrical model uses WKB theory and is incorporated into a 1-D cylindrical multispecies time-dependent fluid code to examine the temporal behavior of ICRF and to estimate the RF power needed to heat FED. Both models use the full 3 x 3 hot plasma dispersion tensor. We find that heating at the second harmonic of deuterium, (f = 55 MHz) with k/sub parallel/ = 0.1 cm-1 appears to be the most attractive scenario. Over 90% of the RF power is damped within one radial pass. Most of the power is deposited at the center in the ions. From the space-time results we find that 40 MW of RF power supplied for 500 ms will heat FED to operating temperatures assuming Alcator-type scaling

  2. Heat-Related Illnesses

    Full Text Available ... Fact Sheet Health & Safety Tips Campaigns SUBSCRIBE Emergencies A-Z Share this! Home » Emergency 101 Heat-Related ... if the person becomes unconscious. READ IN EMERGENCIES A-Z Seizures Teeth (Dental Emergencies) Choking (Heimlich Maneuver) ...

  3. Heat Exhaustion and Heatstroke

    ... activity. Drink extra water all day. Keep in mind that heat-related illnesses are not only caused by high temperatures and a loss of fluids, but also a lack of salt in the body. Some sports drinks can help replenish the salt ...


    A. I. Kolosov; A. A. Sedaev


    Problem statement. The paper discusses the problem of estimation of prospects of heat accumulation in the combined systems of heat supply with the use of low potential energy of renewable sources (sun and ground) and heat pumps for increase of their potential.Results and conclusions. The use of heat accumulators in combined heating systems that utilize low-potential solar and ground energy as primary energy sources and heat pumps to boost the po-tential of the latter was discussed. A method o...

  5. Conjugate heat and mass transfer in heat mass exchanger ducts

    Zhang, Li-Zhi


    Conjugate Heat and Mass Transfer in Heat Mass Exchanger Ducts bridges the gap between fundamentals and recent discoveries, making it a valuable tool for anyone looking to expand their knowledge of heat exchangers. The first book on the market to cover conjugate heat and mass transfer in heat exchangers, author Li-Zhi Zhang goes beyond the basics to cover recent advancements in equipment for energy use and environmental control (such as heat and moisture recovery ventilators, hollow fiber membrane modules for humidification/dehumidification, membrane modules for air purification, desi

  6. Heat Roadmap Europe: Combining district heating with heat savings to decarbonise the EU energy system

    Six different strategies have recently been proposed for the European Union (EU) energy system in the European Commission's report, Energy Roadmap 2050. The objective for these strategies is to identify how the EU can reach its target of an 80% reduction in annual greenhouse gas emissions in 2050 compared to 1990 levels. None of these scenarios involve the large-scale implementation of district heating, but instead they focus on the electrification of the heating sector (primarily using heat pumps) and/or the large-scale implementation of electricity and heat savings. In this paper, the potential for district heating in the EU between now and 2050 is identified, based on extensive and detailed mapping of the EU heat demand and various supply options. Subsequently, a new ‘district heating plus heat savings’ scenario is technically and economically assessed from an energy systems perspective. The results indicate that with district heating, the EU energy system will be able to achieve the same reductions in primary energy supply and carbon dioxide emissions as the existing alternatives proposed. However, with district heating these goals can be achieved at a lower cost, with heating and cooling costs reduced by approximately 15%. - Highlights: • A new heat atlas is created for the EU27. • District heating and renewable heat potentials are determined for 2030 and 2050. • A new heat strategy based on district heating and individual heat pumps is designed for the EU27. • This new heat strategy is compared to the energy efficiency scenario proposed by the European Commission. • Results indicate that this new heat strategy can reduce heating and cooling costs by ∼15%, which is €100 billion per year

  7. A new waste heat district heating system with combined heat and power (CHP) based on ejector heat exchangers and absorption heat pumps

    A new waste heat district heating system with CHP based on ejector heat exchangers and absorption heat pumps (DH-EHE) is presented to decrease heating energy consumption of existing CHP systems by recovering waste heat of exhausted steam from a steam turbine, which could also increase heat transmission capacity of the primary heating network (PHN) by decreasing temperature of the return water of existing PHN. A new ejector heat exchanger based on ejector refrigeration cycle is invented to decrease temperature of the return water of PHN to 30 °C under the designed case. DH-EHE is analyzed in terms of laws of thermodynamics and economics. Compared to conventional district heating systems with CHP (CDH), DH-EHE can decrease consumption of steam extracted from a steam turbine by 41.4% and increase heat transmission capacity of the existing PHN by 66.7% without changing the flow rate of circulating water. The heating cost of DH-EHE is 8.62 ¥/GJ less than that of CDH. Compared to CDH, the recovery period of additional investment of DH-EHE is about two years. DH-EHE shows better economic and environmental benefits, which is promising for both district heating systems for long-distance heat transmission and waste heat district heating systems. - Highlights: • Heating capacity of this new heating system increases by 41% by waste heat recovery. • Temperature of return water of the primary heating network can be reduced to 30 °C. • Heating cost of new heating system is 8.62¥/GJ less than that of conventional one. • The recovery period of additional investment of new heating system is about 2 years. • This new heating system shows better economic and environmental benefits

  8. Heat exchanger performance monitoring guidelines

    Fouling can occur in many heat exchanger applications in a way that impedes heat transfer and fluid flow and reduces the heat transfer or performance capability of the heat exchanger. Fouling may be significant for heat exchanger surfaces and flow paths in contact with plant service water. This report presents guidelines for performance monitoring of heat exchangers subject to fouling. Guidelines include selection of heat exchangers to monitor based on system function, safety function and system configuration. Five monitoring methods are discussed: the heat transfer, temperature monitoring, temperature effectiveness, delta P and periodic maintenance methods. Guidelines are included for selecting the appropriate monitoring methods and for implementing the selected methods. The report also includes a bibliography, example calculations, and technical notes applicable to the heat transfer method

  9. Heat transfer in SiC compact heat exchanger

    For development of a compact SiC heat exchanger, numerical heat transfer analysis was conducted to investigate its performance for a wide range of thermal media, liquid LiPb and helium gas, flow rates. The numerical model used was based on the heat exchanger test module developed by the authors. Within the authors' experimental range, the heat quantity transferred from high temperature liquid LiPb to helium gas and the overall heat transfer coefficients obtained numerically are in agreement with the experimental results. Therefore, the numerical model has proved to be valid for estimation of heat transfer phenomena in the heat exchanger in incompressible regime. The heat quantity transferred from LiPb to He amounts up to 3.7 kW at helium pressure of 0.5 MPa. On the basis of the numerical results, a correlation for helium forced convection heat transfer in the heat exchanger is presented, which describes numerical results with an error of 1%. For heat transfer in LiPb, the Nusselt numbers calculated from an existing correlation for liquid metal heat transfer agree well with the present numerical results. The heat transfer of LiPb in the SiC compact heat exchanger would possibly be predicted from the conventional correlations based on the studies of liquid metal convective heat transfer. A concept of SiC compact heat exchanger studied could be applied to a design of intermediate heat exchangers operating at high temperatures in fusion reactor, as well as HTTR and VHTR systems.

  10. Heat Roadmap Europe: Identifying strategic heat synergy regions

    This study presents a methodology to assess annual excess heat volumes from fuel combustion activities in energy and industry sector facilities based on carbon dioxide emission data. The aim is to determine regional balances of excess heat relative heat demands for all third level administrative regions in the European Union (EU) and to identify strategic regions suitable for large-scale implementation of district heating. The approach is motivated since the efficiency of current supply structures to meet building heat demands, mainly characterised by direct use of primary energy sources, is low and improvable. District heating is conceived as an urban supply side energy efficiency measure employable to enhance energy system efficiency by increased excess heat recoveries; hereby reducing primary energy demands by fuel substitution. However, the importance of heat has long been underestimated in EU decarbonisation strategies and local heat synergies have often been overlooked in energy models used for such scenarios. Study results indicate that 46% of all excess heat in EU27, corresponding to 31% of total building heat demands, is located within identified strategic regions. Still, a realisation of these rich opportunities will require higher recognition of the heat sector in future EU energy policy. - Highlights: • EU27 energy and industry sector heat recycling resources are mapped and quantified. • Target regions for large-scale implementation of district heating are identified. • 46% of total EU27 excess heat volume is seized in 63 strategic heat synergy regions. • Large urban zones have lead roles to play in transition to sustainability in Europe. • Higher recognition of heat sector is needed in future EU energy policy for realisation

  11. Comparison of Thermal Comfort by Radiant Heating and Convective Heating

    Shigeru Imai


    Full Text Available Currently, convective heating with a heat-pump system, which has high energy efficiency, is popular for room heating. However, it is possible that energy savings using convective heating can be further improved using heat pumps that service both occupied and unoccupied spaces. Moreover, convective heating increases vertical temperature gradients in a room; thus, it is hard to say whether occupants are being provided with sufficient thermal comfort. The purpose of this study is to compare the thermal comfort provided by both radiant and convective heating systems. In this study, a small office room was modeled, and then temperature and airflow distributions in the room were calculated by Computational Fluid Dynamics (CFD simulations using ESP-r (Environmental research simulation software. Furthermore, distributions of Standard Effective Temperatures (SET* were calculated using the air temperature distributions obtained from the CFD simulations, which allows us to compare the thermal comfort provided by convective heating with that provided by radiant heating. The results show that radiant heating can provide satisfactory thermal comfort, even when the room air temperature is low. However, thermal comfort also depends on the temperature of blowing air, and blowing air must reach occupied regions; thus, only radiant heating cannot circulate sufficient air. In contrast, convective heating increases vertical temperature gradients in a room. Therefore, rather than using only radiant or convective heating, it may be more effective to combine them efficiently.

  12. Competitivity of biofuels in heating

    The competitivity of indigenous fuels in heating of residential houses in comparison with imported fuels, and both electricity and district heating, has been studied in this research, ordered by the Finnish Ministry of Trade and Industry. Heating plants of residential house scale (20-1000 kW) have been investigated in the research. Only the new heating plants are included in the investigation. The heat generation calculations concerning the residential heating plants have been made for following indigenous fuels: sod peat, fuel-chips, peat and wood pellets, firewood and straw. In addition to these, the calculations have been made for light fuel-oil, electric heating, district heating and natural gas. The local energy tariffs have to be taken into account in electric heating, district heating and natural gas heating. A calculation model, based on flowsheet calculation, forms the main result of the project. By using the model it is possible to update the competitivity data rapidly. Of all the indigenous fuels, sod peat and fuel-chips appeared to be competitive with electric and district heating costs in nearly all scales investigated. The construction of the heat generation costs of solid indigenous fuels differs remarkably from those of electric and district heating. The main part of the heating costs of wood chips and sod peat is formed of fixed costs; i.e. of investment costs and of the costs of heating and control work. The energy costs are the highest costs items in electric an district heating, as well as in the oil heating. It is possible to improve the competitivity of biofuels by developing cheaper boilers and fuel processing and storage devices

  13. Prototype solar heating and combined heating cooling systems


    The design and development of eight prototype solar heating and combined heating and cooling systems is discussed. The program management and systems engineering are reported, and operational test sites are identified.

  14. Geothermal heat-pump systems of heat supply

    The data on the multilayer operation of the objects, located in the climatic conditions of the central area of Russia and equipped with the geothermal heat-pumping systems of the heat supply are presented. The results of the analytical studies on evaluating the geothermal heat-pumping systems of the heat supply integration efficiency into the structure of the energy supply system, prevailing in the country, are presented

  15. Elucidation of the heat flux limit from magnetic island heating

    Gupta, A; Tokar, M. Z.; Wolf, R C


    Recent experiments on heating of magnetic islands in a tokamak are analyzed to assess plasma transport characteristics. By comparing with the experimental data, both perpendicular and parallel components of the electron heat conductivity in the island are determined. As a consequence, the so-called heat-flux limit factor xi, the ratio of the parallel heat conduction flux in a collisionless plasma to that transferred by free-streaming electrons, can be estimated. The found factor xi does not c...

  16. Control of heat source in a heat conduction problem

    Lyashenko, V.; Kobilskaya, E.


    The mathematical model of thermal processes during the heat treatment of a moving axisymmetric environment, for example wire. is considered. The wire is heated by internal constantly or periodically operating heat source. It is presented in the form of initial-boundary value problem for the unsteady heat equation with internal constantly or periodically operating heat source. The purpose of the work is the definition of control parameter of temperature field of a moving area, which is heated by internal heat source. The control parameters are determined by solving a nonlocal problem for the heat equation. The problem of getting an adequate temperature distribution throughout the heating area is considered. Therefore, a problem of heat source control is solved, in particular, control by electric current. Control of the heat source allows to maintain the necessary, from a technological point of view, temperature in the heating area. In this paper, to find additional information about the source of heat. The integral condition is used in the control problem. Integral condition, which is considered in the work, determines the energy balance of the heating zone and connects the desired temperature distribution in the internal points of area with temperatures at the boundaries. Control quality in an extremum formulation of the problem is assessed using the quadratic functional. In function space, from a physical point of view, proposed functional is the absolute difference between the actual emission of energy and absorbed energy in the heating zone. The absorbed energy is calculated by solving of the boundary value problem. Methods of determining the control parameters of temperature field are proposed. The resulting problem is solved by iterative methods. At different physical conditions, numerical calculations are carried out, control parameters of the heat treatment process are obtained.

  17. A Review on Heat Transfer Improvent of Plate Heat Exchanger

    Abhishek Nandan; Gurpreet Singh Sokhal


    Plate heat exchanger has found a wide range of application in various industries like food industries, chemical industries, power plants etc. It reduces the wastage of energy and improves the overall efficiency of the system. Hence, it must be designed to obtain the maximum heat transfer possible. This paper is presented in order to study the various theories and results given over the improvement of heat transfer performance in a plate heat exchanger. However, there is still a la...

  18. Research of heat exchange rate of the pulsating heat pipe

    Kravets V. Yu.; Naumova A. M.; Vovkogon A. M.


    Given article presents experimental research of heat transfer characteristics of the pulsating heat pipe (PHP) which consists of seven coils with 1 mm inner diameter. Water was used as the heat carrier. PHP construction, measuring circuit and research technique are presented. It is shown that under PHP functioning there are two characteristic modes of operation, which can be distinguished by values of thermal resistance. PHP heat exchange features are disclosed.

  19. Minimum heat transfer area for Total Site heat recovery

    Highlights: • Methodology development for Total Site heat recovery with of intermediate utility. • Selection of temperature for intermediate utilities of Total Site. • Capital cost reduction for heat exchangers network design on Total Site level. • Recommendation for selection of heat exchangers design of Total Site. - Abstract: In this paper a further development of methodology for decreasing the capital cost for Total Site heat recovery by use of different utility levels is proposed. The capital cost of heat recovery system is estimated for certain temperature level of intermediate utility applying Total Site Profiles. Heat transfer area is reduced by selection of appropriate temperature of intermediate utility. Minimum of heat transfer area depends on slopes of Total Site Profiles in each enthalpy interval. This approach allows estimating the minimum of heat transfer area for heat recovery on Total Site level. Case study is performed for fixed film heat transfer coefficients of process streams and intermediate utilities. It indicates that the total heat transfer area of heat recovery can be different up to 49.15% for different utility temperatures

  20. High temperature heat exchange: nuclear process heat applications

    The unique element of the HTGR system is the high-temperature operation and the need for heat exchanger equipment to transfer nuclear heat from the reactor to the process application. This paper discusses the potential applications of the HTGR in both synthetic fuel production and nuclear steel making and presents the design considerations for the high-temperature heat exchanger equipment

  1. Industrial Heat Pump for a High Temperature District Heating Application

    Poulsen, Claus Nørgaard


    Domestic heat pumps for shallow geothermal heating of family houses are popular and the range and supply of standard solutions is large. However, in applications for large capacities and temperatures, like district heating in the mega Watt range, standard solutions for high temperatures are scarce...

  2. Solar district heating

    The model presented here analyzes solar district heating systems on the basis of the power supplied at the grid feeding point. Consumption patterns are taken into account only in the form of different preset load curves. Processes are selected in consideration of the following aspects: (1) The design of a solar district heating system (collector surface, storage volume) depends on the expected contribution of solar power to electricity supply. For each of the key years 1989, 2005 and 2020, a low, average and high contribution were investigated, from which design concepts for other supply rates can be derived. (2) Yields and economic efficiency of solar systems also depend on collector sites and consumption patterns. 10 variants each with low and very high contributions of solar power were calculated for the key year 2020. (orig.)

  3. Heat-resistant materials


    This handbook covers the complete spectrum of technology dealing with heat-resistant materials, including high-temperature characteristics, effects of processing and microstructure on high-temperature properties, materials selection guidelines for industrial applications, and life-assessment methods. Also included is information on comparative properties that allows the ranking of alloy performance, effects of processing and microstructure on high-temperature properties, high-temperature oxidation and corrosion-resistant coatings for superalloys, and design guidelines for applications involving creep and/or oxidation. Contents: General introduction (high-temperature materials characteristics, and mechanical and corrosion properties, and industrial applications); Properties of Ferrous Heat-Resistant Alloys (carbon, alloy, and stainless steels; alloy cast irons; and high alloy cast steels); Properties of superalloys (metallurgy and processing, mechanical and corrosion properties, degradation, and protective coa...

  4. Heat Pipes For Alyeska


    The heat pipes job is to keep the arctic ground frozen. The permafrost soil alternately freezes and thaws with seasonal temperature changes causing surface dislocations and problems for the builders. In winter, a phenomenon called frost-heaving uplifts the soil. It is something like the creation of highway potholes by the freezing of rainwater below the roadbed, but frost-heaving exerts a far greater force. Thawing of the frost in the summer causes the soil to settle unevenly. Therefore it is necessary to keep the soil in a continually frozen state so the pipeline won't rupture. To solve this problem, McDonnell Douglas Corp. applied heat pipe principles in the design of the vertical supports that hold up the pipeline.

  5. Tubular heat exchanger

    The invention concerns a heat exchanger of which the tubes, placed in a long casing, cross the casing cover in a sealed manner. These tubes are fixed to the tube plate forming this cover or to the branch tubes it comprises by means of compression joints. These joints make it possible to do away with welds that are sources of defects and to improve the operational safety of the apparatus. An advantageous form of the heat exchanger under the invention includes a manifold for each thermal exchange fluid, and one end of each tube is connected to this manifold by a pipe that is itself connected to the tube by a threaded connection. The latter provides for easy disconnection of the pipe in order to introduce a probe for inspecting the state of the tubes

  6. Impedance and component heating

    Métral, E; Mounet, N; Pieloni, T; Salvant, B


    The impedance is a complex function of frequency, which represents, for the plane under consideration (longitudinal, horizontal or vertical), the force integrated over the length of an element, from a “source” to a “test” wave, normalized by their charges. In general, the impedance in a given plane is a nonlinear function of the test and source transverse coordinates, but it is most of the time sufficient to consider only the first few linear terms. Impedances can influence the motion of trailing particles, in the longitudinal and in one or both transverse directions, leading to energy loss, beam instabilities, or producing undesirable secondary effects such as excessive heating of sensitive components at or near the chamber wall, called beam-induced RF heating. The LHC performance limitations linked to impedances encountered during the 2010-2012 run are reviewed and the currently expected situation during the HL-LHC era is discussed.

  7. Hybrid Heat Exchangers

    Tu, Jianping Gene; Shih, Wei


    A hybrid light-weight heat exchanger concept has been developed that uses high-conductivity carbon-carbon (C-C) composites as the heat-transfer fins and uses conventional high-temperature metals, such as Inconel, nickel, and titanium as the parting sheets to meet leakage and structural requirements. In order to maximize thermal conductivity, the majority of carbon fiber is aligned in the fin direction resulting in 300 W/m.K or higher conductivity in the fin directions. As a result of this fiber orientation, the coefficient of thermal expansion (CTE) of the C-C composite in both non-fiber directions matches well with the CTE of various high-temperature metal alloys. This allows the joining of fins and parting sheets by using high-temperature braze alloys.

  8. Adaptive Heat Engine

    Allahverdyan, A. E.; Babajanyan, S. G.; Martirosyan, N. H.; Melkikh, A. V.


    A major limitation of many heat engines is that their functioning demands on-line control and/or an external fitting between the environmental parameters (e.g., temperatures of thermal baths) and internal parameters of the engine. We study a model for an adaptive heat engine, where—due to feedback from the functional part—the engine's structure adapts to given thermal baths. Hence, no on-line control and no external fitting are needed. The engine can employ unknown resources; it can also adapt to results of its own functioning that make the bath temperatures closer. We determine resources of adaptation and relate them to the prior information available about the environment.

  9. Heat Transfer Analogies

    This report contains descriptions of various analogues utilised to study different steady-state and unsteady-state heat transfer problems. The analogues covered are as follows: 1 . Hydraulic: a) water flow b) air flow 2. Membrane 3. Geometric Electrical: a) Electrolytic-tank b) Conducting sheet 4. Network; a) Resistance b) R-C A comparison of the different analogues is presented in the form of a table

  10. Financial heat machine

    Andrei Khrennikov


    We consider dynamics of financial markets as dynamics of expectations and discuss such a dynamics from the point of view of phenomenological thermodynamics. We describe a financial Carnot cycle and the financial analogue of a heat machine. We see, that while in physics a perpetuum mobile is absolutely impossible, in economics such mobile may exist under some conditions. Our thermodynamical model for the financial market induces a rather unusual interpretation of the role of financial crises. ...

  11. Heat determinant on manifolds

    Avramidi, Ivan G.; Buckman, Benjamin J.


    We introduce and study new invariants associated with Laplace type elliptic partial differential operators on manifolds. These invariants are constructed by using the off-diagonal heat kernel; they are not pure spectral invariants, that is, they depend not only on the eigenvalues but also on the corresponding eigenfunctions in a non-trivial way. We compute the first three low-order invariants explicitly.


    Chambers, E.S.; Garren, A.A.; Kippenhan, D.O.; Lamb, W.A.S.; Riddell, R.J. Jr.


    The heating of ions in a magnetically confined plasma is accomplished by the application of an azimuthal radiofrequency electric field to the plasma at ion cyclotron resonance. The principal novelty resides in the provision of an output tank coil of a radiofrequency driver to induce the radiofrequency field in the plasma and of electron current bridge means at the ends of the plasma for suppressing radial polarization whereby the radiofrequency energy is transferred to the ions with high efficiency.

  13. Membrane Based Heat Exchanger

    Aarnes, Sofie Marie


    Reduction of the energy used to acclimatise buildings is a huge challenge simultaneously with the implementation of air tight low energy buildings. In residential buildings with several living units centralised air handling units are the most energy efficient system. However, in a centralised system there is important to avoid leakages of pollutions between the exhaust air and the supply air. This leads to that flat plate heat exchangers are used instead of the more energy efficient rotary he...

  14. Urban heat island 1

    Bühler, Oliver; Jensen, Marina Bergen; Petersen, Karen Sejr


    Urban Heat Island beskriver det forhold, at temperaturen i byområder er højere end temperaturen i tilgrænsede landområder. Årsagen hertil ligger i den urbane arealanvendelse, hvor en mindre andel af arealerne er dækket af vegetation, og en større andel består af forseglede arealer....

  15. Heat Capacity Mapping Mission

    Nilsson, C. S.; Andrews, J. C.; Scully-Power, P.; Ball, S.; Speechley, G.; Latham, A. R. (Principal Investigator)


    The Tasman Front was delineated by airborne expendable bathythermograph survey; and an Heat Capacity Mapping Mission (HCMM) IR image on the same day shows the same principal features as determined from ground-truth. It is clear that digital enhancement of HCMM images is necessary to map ocean surface temperatures and when done, the Tasman Front and other oceanographic features can be mapped by this method, even through considerable scattered cloud cover.

  16. A study of the heating and heat storage problems in passive solar heated room with greenhouse

    CHENWei; LIUWei


    In this paper, heating and heat storage in passive solar heating room with greenhouse has been studied. The unsteady numerical simulation is employed to analyze the performance of the flow and temperature field for the typical sunny day of Wuhan, China, in winter in the heating system. The floor of passive solar heating room with a convective hole or not has great effects on temperature distribution and gas flow in heat storage layer of this system. Properties of the bed worked as solar absorber and storage layer have also been studied.

  17. Critical heat flux evaluation

    Critical heat flux (CHF) is of importance for nuclear safety and represents the major limiting factors for reactor cores. Critical heat flux is caused by a sharp reduction in the heat transfer coefficient located at the outer surface of fuel rods. Safety requires that this phenomenon also called the boiling crisis should be precluded under nominal or incidental conditions (Class I and II events). CHF evaluation in reactor cores is basically a two-step approach. Fuel assemblies are first tested in experimental loops in order to determine CHF limits under various flow conditions. Then, core thermal-hydraulic calculations are performed for safety evaluation. The paper will go into more details about the boiling crisis in order to pinpoint complexity and lack of fundamental understanding in many areas. Experimental test sections needed to collect data over wide thermal-hydraulic and geometric ranges are described CHF safety margin evaluation in reactors cores is discussed by presenting how uncertainties are mentioned. From basic considerations to current concerns, the following topics are discussed; knowledge of the boiling crisis, CHF predictors, and advances thermal-hydraulic codes. (authors). 15 refs., 4 figs

  18. Stirling Engine Heat Pump

    Kagawa, Noboru

    Recent advances in the feasibility studies related to the Stirling engines and Stirling engine heat pumps which have been considered attractive due to their promising role in helping to solve the global environmental and energy problems,are reviewed. This article begins to describe the brief history of the Stirling engines and theoretical thermodynamic analysis of the Stirling cycle in order to understand several advantages on the Stirling engine. Furthermore,they could throw light on our question why the dream engines had not been promoted to practical applications during two hundred years. The present review shows that the Stirling engines with several unique advantages including 30 to 40% thermal efficiency and preferable exhaust characteristics,had been designed and constructed by recent tackling for the development of the advanced automobile and other applications using them. Based on the current state of art,it is being provided to push the Stirling engines combined with heat pumps based on the reversed Rankine cycle to the market. At present,however, many problems, especially for the durability, cost, and delicate engine parts must be enforced to solve. In addition,there are some possibilities which can increase the attractiveness of the Stirling engines and heat pumps. The review closes with suggestions for further research.

  19. Nucleate boiling heat transfer

    Saiz Jabardo, J.M. [Universidade da Coruna (Spain). Escola Politecnica Superior], e-mail:


    Nucleate boiling heat transfer has been intensely studied during the last 70 years. However boiling remains a science to be understood and equated. In other words, using the definition given by Boulding, it is an 'insecure science'. It would be pretentious of the part of the author to explore all the nuances that the title of the paper suggests in a single conference paper. Instead the paper will focus on one interesting aspect such as the effect of the surface microstructure on nucleate boiling heat transfer. A summary of a chronological literature survey is done followed by an analysis of the results of an experimental investigation of boiling on tubes of different materials and surface roughness. The effect of the surface roughness is performed through data from the boiling of refrigerants R-134a and R-123, medium and low pressure refrigerants, respectively. In order to investigate the extent to which the surface roughness affects boiling heat transfer, very rough surfaces (4.6 {mu}m and 10.5 {mu}m ) have been tested. Though most of the data confirm previous literature trends, the very rough surfaces present a peculiar behaviour with respect to that of the smoother surfaces (Ra<3.0 {mu}m). (author)

  20. Heat exchanger tube tool

    Certain types of heat-exchangers have tubes opening through a tube sheet to a manifold having an access opening offset from alignment with the tube ends. A tool for inserting a device, such as for inspection or repair, is provided for use in such instances. The tool is formed by a flexible guide tube insertable through the access opening and having an inner end provided with a connector for connection with the opening of the tube in which the device is to be inserted, and an outer end which remains outside of the chamber, the guide tube having adequate length for this arrangement. A flexible transport hose for internally transporting the device slides inside of the guide tube. This hose is long enough to slide through the guide tube, into the heat-exchanger tube, and through the latter to the extent required for the use of the device. The guide tube must be bent to reach the end of the heat-exchanger tube and the latter may be constructed with a bend, the hose carrying anit-friction elements at interspaced locations along its length to make it possible for the hose to negotiate such bends while sliding to the location where the use of the device is required

  1. Conduction heat transfer solutions

    This text is a collection of solutions to a variety of heat conduction problems found in numerous publications, such as textbooks, handbooks, journals, reports, etc. Its purpose is to assemble these solutions into one source that can facilitate the search for a particular problem solution. Generally, it is intended to be a handbook on the subject of heat conduction. There are twelve sections of solutions which correspond with the class of problems found in each. Geometry, state, boundary conditions, and other categories are used to classify the problems. Each problem is concisely described by geometry and condition statements, and many times a descriptive sketch is also included. The introduction presents a synopsis on the theory, differential equations, and boundary conditions for conduction heat transfer. Some discussion is given on the use and interpretation of solutions. Supplementary data such as mathematical functions, convection correlations, and thermal properties are included for aiding the user in computing numerical values from the solutions. 155 figs., 92 refs., 9 tabs

  2. Conduction heat transfer solutions

    This text is a collection of solutions to a variety of heat conduction problems found in numerous publications, such as textbooks, handbooks, journals, reports, etc. Its purpose is to assemble these solutions into one source that can facilitate the search for a particular problem solution. Generally, it is intended to be a handbook on the subject of heat conduction. This material is useful for engineers, scientists, technologists, and designers of all disciplines, particularly those who design thermal systems or estimate temperatures and heat transfer rates in structures. More than 500 problem solutions and relevant data are tabulated for easy retrieval. There are twelve sections of solutions which correspond with the class of problems found in each. Geometry, state, boundary conditions, and other categories are used to classify the problems. A case number is assigned to each problem for cross-referencing, and also for future reference. Each problem is concisely described by geometry and condition statements, and many times a descriptive sketch is also included. At least one source reference is given so that the user can review the methods used to derive the solutions. Problem solutions are given in the form of equations, graphs, and tables of data, all of which are also identified by problem case numbers and source references

  3. Adjustable Induction-Heating Coil

    Ellis, Rod; Bartolotta, Paul


    Improved design for induction-heating work coil facilitates optimization of heating in different metal specimens. Three segments adjusted independently to obtain desired distribution of temperature. Reduces time needed to achieve required temperature profiles.

  4. Heat exchanger with removable orifice

    A nuclear reactor steam generator heat exchanger is described which has orifices in the entrance openings of the heat exchange tubes which, although securely fastened to the tubes, can be easily removed by remote handling equipment. (U.K.)

  5. VTX HyHeat Project

    National Aeronautics and Space Administration — In this project Orbital Technologies Corporation (ORBITEC) will utilize its unique vortex propulsion technology to develop a high-capacity heating system to heat...

  6. Heat Waves Hit Seniors Hardest

    ... Heat Waves Hit Seniors Hardest Risk of high-temperature trouble ... much of the Northeast struggles with a heat wave that isn't expected to ease until the ...

  7. Heat Waves Are Health Threats

    ... Heat Waves Are Health Threats Drink plenty of water and ... 2016 SATURDAY, July 2, 2016 (HealthDay News) -- Heat waves are more than uncomfortable, they can be deadly. ...

  8. Protecting Yourself from Heat Stress

    ... NIOSH NIOSH Fast Facts: Protecting Yourself from Heat Stress Language: English Español (Spanish) Kreyol Haitien (Haitian Creole) ... 2010 DHHS (NIOSH) Publication Number 2010-114 Heat stress, from exertion or hot environments, places workers at ...

  9. Transient heating of moving objects

    E.I. Baida


    Full Text Available A mathematical model of transient and quasistatic heating of moving objects by various heat sources is considered. The mathematical formulation of the problem is described, examples of thermal calculation given.

  10. Heat pipe applications workshop report

    Ranken, W.A.


    The proceedings of the Heat Pipe Applications Workshop, held at the Los Alamos Scientific Laboratory October 20-21, 1977, are reported. This workshop, which brought together representatives of the Department of Energy and of a dozen industrial organizations actively engaged in the development and marketing of heat pipe equipment, was convened for the purpose of defining ways of accelerating the development and application of heat pipe technology. Recommendations from the three study groups formed by the participants are presented. These deal with such subjects as: (1) the problem encountered in obtaining support for the development of broadly applicable technologies, (2) the need for applications studies, (3) the establishment of a heat pipe technology center of excellence, (4) the role the Department of Energy might take with regard to heat pipe development and application, and (5) coordination of heat pipe industry efforts to raise the general level of understanding and acceptance of heat pipe solutions to heat control and transfer problems.