WorldWideScience

Sample records for temperature solar thermal

  1. High temperature solar thermal technology: The North Africa Market

    Energy Technology Data Exchange (ETDEWEB)

    1990-12-01

    High temperature solar thermal (HTST) technology offers an attractive option for both industrialized and non-industrialized countries to generate electricity and industrial process steam. The purpose of this report is to assess the potential market for solar thermal applications in the North African countries of Algeria, Egypt, Morocco and Tunisia. North Africa was selected because of its outstanding solar resource base and the variety of applications to be found there. Diminishing oil and gas resources, coupled with expanding energy needs, opens a large potential market for the US industry. The US high temperature solar trough industry has little competition globally and could build a large market in these areas. The US is already familiar with certain solar markets in North Africa due to the supplying of substantial quantities of US-manufactured flat plate collectors to this region.

  2. MINICHANNEL-TUBE SOLAR THERMAL COLLECTORS FOR LOW TO MEDIUM TEMPERATURE APPLICATIONS

    OpenAIRE

    Duong, Thuc

    2015-01-01

    Novel minichannel-tube solar thermal collectors for low to medium temperature applications are introduced. Two types of minichannel solar thermal collectors are analyzed experimentally: aluminum minichannel solar collector for low temperature applications, and copper minichannel solar collector for low to medium temperature applications.The aluminum minichannel solar collector has been tested for over a year alongside a conventional copper flat-plate solar collector of similar dimensions as t...

  3. High temperature latent heat thermal energy storage to augment solar thermal propulsion for microsatellites

    Science.gov (United States)

    Gilpin, Matthew R.

    Solar thermal propulsion (STP) offers an unique combination of thrust and efficiency, providing greater total DeltaV capability than chemical propulsion systems without the order of magnitude increase in total mission duration associated with electric propulsion. Despite an over 50 year development history, no STP spacecraft has flown to-date as both perceived and actual complexity have overshadowed the potential performance benefit in relation to conventional technologies. The trend in solar thermal research over the past two decades has been towards simplification and miniaturization to overcome this complexity barrier in an effort finally mount an in-flight test. A review of micro-propulsion technologies recently conducted by the Air Force Research Laboratory (AFRL) has identified solar thermal propulsion as a promising configuration for microsatellite missions requiring a substantial Delta V and recommended further study. A STP system provides performance which cannot be matched by conventional propulsion technologies in the context of the proposed microsatellite ''inspector" requiring rapid delivery of greater than 1500 m/s DeltaV. With this mission profile as the target, the development of an effective STP architecture goes beyond incremental improvements and enables a new class of microsatellite missions. Here, it is proposed that a bi-modal solar thermal propulsion system on a microsatellite platform can provide a greater than 50% increase in Delta V vs. chemical systems while maintaining delivery times measured in days. The realization of a microsatellite scale bi-modal STP system requires the integration of multiple new technologies, and with the exception of high performance thermal energy storage, the long history of STP development has provided "ready" solutions. For the target bi-modal STP microsatellite, sensible heat thermal energy storage is insufficient and the development of high temperature latent heat thermal energy storage is an enabling

  4. Near-Field Thermal Radiation for Solar Thermophotovoltaics and High Temperature Thermal Logic and Memory Applications

    Science.gov (United States)

    Elzouka, Mahmoud

    This dissertation investigates Near-Field Thermal Radiation (NFTR) applied to MEMS-based concentrated solar thermophotovoltaics (STPV) energy conversion and thermal memory and logics. NFTR is the exchange of thermal radiation energy at nano/microscale; when separation between the hot and cold objects is less than dominant radiation wavelength (˜1 mum). NFTR is particularly of interest to the above applications due to its high rate of energy transfer, exceeding the blackbody limit by orders of magnitude, and its strong dependence on separation gap size, surface nano/microstructure and material properties. Concentrated STPV system converts solar radiation to electricity using heat as an intermediary through a thermally coupled absorber/emitter, which causes STPV to have one of the highest solar-to-electricity conversion efficiency limits (85.4%). Modeling of a near-field concentrated STPV microsystem is carried out to investigate the use of STPV based solid-state energy conversion as high power density MEMS power generator. Numerical results for In 0.18Ga0.82Sb PV cell illuminated with tungsten emitter showed significant enhancement in energy transfer, resulting in output power densities as high as 60 W/cm2; 30 times higher than the equivalent far-field power density. On thermal computing, this dissertation demonstrates near-field heat transfer enabled high temperature NanoThermoMechanical memory and logics. Unlike electronics, NanoThermoMechanical memory and logic devices use heat instead of electricity to record and process data; hence they can operate in harsh environments where electronics typically fail. NanoThermoMechanical devices achieve memory and thermal rectification functions through the coupling of near-field thermal radiation and thermal expansion in microstructures, resulting in nonlinear heat transfer between two temperature terminals. Numerical modeling of a conceptual NanoThermoMechanical is carried out; results include the dynamic response under

  5. High temperature thermal storage for solar gas turbines using encapsulated phase change materials

    CSIR Research Space (South Africa)

    Klein, P

    2014-01-01

    Full Text Available The development of high temperature thermal storage systems is required to increase the solar share of solar-hybrid gas turbine cycles. This paper proposes a pressurised packed bed of Encapsulated Phase Change Materials (EPCM) as a thermal storage...

  6. Parametric analysis of a high temperature packed bed thermal storage design for a solar gas turbine

    CSIR Research Space (South Africa)

    Klein, P

    2015-08-01

    Full Text Available The development of a high temperature Thermal Energy Storage (TES) system will allow for high solar shares in Solar Gas Turbine (SGT) plants. In this research a pressurised storage solution is proposed that utilises a packed bed of alumina spheres...

  7. Calculation facility. Solar thermal low-temperature; Calculo de una instalacion. Energia solar termica de baja temperatura

    Energy Technology Data Exchange (ETDEWEB)

    Comes, P.

    2010-07-01

    The aim of this paper is to express in a simple procedure to follow for the calculation of a solar thermal installation of low temperature. It will take as a model for an installation in operation Ariston washing a tunnel Sant Carles de la Rapita Tarragona. (Author)

  8. High-temperature selective solar thermal absorber based on Fabry-Perot resonance cavity

    Science.gov (United States)

    Wang, Hao; Wang, Liping

    2015-09-01

    In this work, we investigate the design, fabrication and characterization of a multilayer selective solar absorber made of metallic and dielectric thin films. The investigated selective absorber exhibits theoretical spectral absorptance higher than 95% within solar spectrum and infrared emittance lower than 5%, due to the Fabry-Perot resonance and antireflection effect. In terms of fabrication, different materials are tested under high temperatures in order to obtain the structure with best thermal stability. Structures with different materials are fabricated with sputtering, chemical vapor deposition and electron beam evaporation techniques. The near normal reflectance is characterized with a Fourier Transform Infrared spectrometer for these structures before and after heat treatment. Meanwhile, Rutherford backscattering Spectroscopy is employed to analyze the diffusion and oxidation conditions during the heating process. Moreover, better material choice and fabrication techniques are considered to construct solar absorber sample with better high temperature thermal stability.

  9. Numerical simulation of a high temperature thermal storage unit for solar gas turbine applications

    CSIR Research Space (South Africa)

    Klein, P

    2010-09-01

    Full Text Available The implementation of thermal storage systems allows concentrating solar power plants to generate predictable power delivery to the grid by mitigating the variability of solar energy supply. However, while thermal storage solutions exist for Rankine...

  10. Carbon dioxide as working fluid for medium and high-temperature concentrated solar thermal systems

    Directory of Open Access Journals (Sweden)

    Van Duong

    2014-03-01

    Full Text Available This paper explores the benefits and drawbacks of using carbon dioxide in solar thermal systems at medium and high operating temperatures. For medium temperatures, application of CO2 in non-imaging-optics based compound parabolic concentrators (CPC combined with evacuated-tube collectors is studied. These collectors have been shown to obtain efficiencies higher than 40% operating at around 200℃ without the need of tracking. Validated numerical models of external compound parabolic concentrators (XCPCs are used to simulate their performance using CO2 as working fluid. For higher temperatures, a mathematical model is implemented to analyze the operating performance of a parabolic trough solar collector (PTC using CO2 at temperatures between 100℃ and 600℃.

  11. High-Flux, High-Temperature Thermal Vacuum Qualification Testing of a Solar Receiver Aperture Shield

    Science.gov (United States)

    Kerslake, Thomas W.; Mason, Lee S.; Strumpf, Hal J.

    1997-01-01

    As part of the International Space Station (ISS) Phase 1 program, NASA Lewis Research Center (LERC) and the Russian Space Agency (RSA) teamed together to design, build and flight test the world's first orbital Solar Dynamic Power System (SDPS) on the Russian space station Mir. The Solar Dynamic Flight Demonstration (SDFD) program was to operate a nominal 2 kWe SDPS on Mir for a period up to 1-year starting in late 1997. Unfortunately, the SDFD mission was demanifested from the ISS phase 1 shuttle program in early 1996. However, substantial flight hardware and prototypical flight hardware was built including a heat receiver and aperture shield. The aperture shield comprises the front face of the cylindrical cavity heat receiver and is located at the focal plane of the solar concentrator. It is constructed of a stainless steel plate with a 1-m outside diameter, a 0.24-m inside diameter and covered with high-temperature, refractory metal Multi-Foil Insulation (MFI). The aperture shield must minimize heat loss from the receiver cavity, provide a stiff, high strength structure to accommodate shuttle launch loads and protect receiver structures from highly concentrated solar fluxes during concentrator off-pointing events. To satisfy Mir operational safety protocols, the aperture shield was required to accommodate direct impingement of the intensely concentrated solar image for a 1-hour period. To verify thermal-structural durability under the anticipated high-flux, high-temperature loading, an aperture shield test article was constructed and underwent a series of two tests in a large thermal vacuum chamber configured with a reflective, point-focus solar concentrator and a solar simulator. The test article was positioned near the focal plane and exposed to concentrated solar flux for a period of 1-hour. In the first test, a near equilibrium temperature of 1862 K was attained in the center of the shield hot spot. In the second test, with increased incident flux, a near

  12. High-temperature thermal storage systems for advanced solar receivers materials selections

    Science.gov (United States)

    Wilson, D. F.; Devan, J. H.; Howell, M.

    1990-01-01

    Advanced space power systems that use solar energy and Brayton or Stirling heat engines require thermal energy storage (TES) systems to operate continuously through periods of shade. The receiver storage units, key elements in both Brayton and Stirling systems, are designed to use the latent heat of fusion of phase-change materials (PCMs). The power systems under current consideration for near-future National Aeronautics and Space Administration space missions require working fluid temperatures in the 1100 to 1400 K range. The PCMs under current investigation that gave liquid temperatures within this range are the fluoride family of salts. However, these salts have low thermal conductivity, which causes large temperature gradients in the storage systems. Improvements can be obtained, however, with the use of thermal conductivity enhancements or metallic PCMs. In fact, if suitable containment materials can be found, the use of metallic PCMs would virtually eliminate the orbit associated temperature variations in TES systems. The high thermal conductivity and generally low volume change on melting of germanium and alloys based on silicon make them attractive for storage of thermal energy in space power systems. An approach to solving the containment problem, involving both chemical and physical compatibility, preparation of NiSi/NiSi2, and initial results for containment of germanium and NiSi/NiSi2, are presented.

  13. Bypass Diode Temperature Tests of a Solar Array Coupon Under Space Thermal Environment Conditions

    Science.gov (United States)

    Wright, Kenneth H., Jr.; Schneider, Todd A.; Vaughn, Jason A.; Hoang, Bao; Wong, Frankie; Wu, Gordon

    2016-01-01

    Tests were performed on a 56-cell Advanced Triple Junction solar array coupon whose purpose was to determine margin available for bypass diodes integrated with new, large multi-junction solar cells that are manufactured from a 4-inch wafer. The tests were performed under high vacuum with coupon back side thermal conditions of both cold and ambient. The bypass diodes were subjected to a sequence of increasing discrete current steps from 0 Amp to 2.0 Amp in steps of 0.25 Amp. At each current step, a temperature measurement was obtained via remote viewing by an infrared camera. This paper discusses the experimental methodology, experiment results, and the thermal model.

  14. Design and optimization of nanoparticle-pigmented solar selective absorber coatings for high-temperature concentrating solar thermal systems

    Science.gov (United States)

    Wang, Xiaoxin; Yu, Xiaobai; Fu, Sidan; Lee, Eldred; Kekalo, Katerina; Liu, Jifeng

    2018-01-01

    We present a systematic approach for the design and optimization of nanoparticle-pigmented solar selective absorbers for operation at 750 °C. Using the scattering and absorption cross-sections calculated by Lorenz-Mie scattering theory as input, we employ a four-flux radiative transfer method to investigate the solar selectivity mechanism and optimize the optical-to-thermal conversion efficiency (ηtherm) as a function of the metallic nanoparticle material, the nanoparticle diameter, the volume fraction, and the coating thickness. Among the nanoparticle material candidates in this study, C54-TiSi2 is the best option with an optimized ηtherm = 87.0% for a solar concentration ratio of C = 100 and ηtherm = 94.4% for C = 1000 at 750 °C. NiSi is also a promising candidate comparable to TiSi2 in thermal efficiency. Experimentally, an un-optimized 200 nm-diameter TiSi2 nanoparticle-silicone solar selective coating has already achieved ηtherm = 89.8% for C = 1000 at 750 °C. This performance is consistent with the theoretical model and close to the thermal efficiency of the commercial Pyromark 2500 coatings (90.1%). We also demonstrate that Ni/NiSi core-shell structures embedded in the SiO1.5 matrix is thermally stable at 750 °C for 1000 h in air. These results indicate that silicide cermet coatings are promising to achieve high optical performance and high temperature thermal stability simultaneously.

  15. Temperature comparison of different reflective surfaces of a solar thermal collector

    Science.gov (United States)

    Koh, Yit Yan; Chua, Yaw Long; Chin, Kiat Keong

    2017-09-01

    With the rapid depletion of fossil fuels, the search for application of alternative energy sources becomes more important than ever before. Solar energy has been identified as one of the major renewable energy that will contribute to power generation is years to come. There are two major categories of solar energy applications. Solar thermal collector is one of it. This paper presents an investigation on the effect of different reflecting surfaces on solar thermal collector. Three different reflective surfaces were applied on the surface of the solar thermal collector. Data was collected and analyzed. From the results, the aluminum mirror sheet performed best.

  16. Thermal properties of high temperature vacuum receivers used for parabolic trough solar thermal power system

    Directory of Open Access Journals (Sweden)

    Qinghe Yu

    2017-08-01

    Full Text Available The receiver's emittance and vacuum pressure are the two of great significance issues on the heat-loss which is the main factor reducing the efficiency of the parabolic though systems. In this paper, the thermal steady-state equilibrium method was used to test the receivers’ heat-loss. The receivers with increasing emittance were tested to study the variation of heat-loss. Meanwhile, the variable vacuum pressure in the annulus that affects the efficiency of the system was investigated. The influence of vacuumizing rate and getters on the vacuum pressure and heat-loss were discussed. The result shows that the emittance and vacuum pressure affect the receiver's heat-loss dramatically, and the emittance is the major influence factor on the thermal properties. The receiver with 0.08 emittance and 10−3 Pa vacuum pressure has a satisfactory heat-loss of 215.6 W/m at 400 °C. The analysis further reveals that the synergistic effect of both emittance and vacuum pressure on the heat-loss can be reflected by the packaging temperature of the glass tube, and a fitting formula has been established to estimate the receivers’ heat-loss according to the packaging temperature of the glass tube.

  17. Electromagnetic Acoustic Transducers Applied to High Temperature Plates for Potential Use in the Solar Thermal Industry

    Directory of Open Access Journals (Sweden)

    Maria Kogia

    2015-12-01

    Full Text Available Concentrated Solar Plants (CSPs are used in solar thermal industry for collecting and converting sunlight into electricity. Parabolic trough CSPs are the most widely used type of CSP and an absorber tube is an essential part of them. The hostile operating environment of the absorber tubes, such as high temperatures (400–550 °C, contraction/expansion, and vibrations, may lead them to suffer from creep, thermo-mechanical fatigue, and hot corrosion. Hence, their condition monitoring is of crucial importance and a very challenging task as well. Electromagnetic Acoustic Transducers (EMATs are a promising, non-contact technology of transducers that has the potential to be used for the inspection of large structures at high temperatures by exciting Guided Waves. In this paper, a study regarding the potential use of EMATs in this application and their performance at high temperature is presented. A Periodic Permanent Magnet (PPM EMAT with a racetrack coil, designed to excite Shear Horizontal waves (SH0, has been theoretically and experimentally evaluated at both room and high temperatures.

  18. Evaluation of annual efficiencies of high temperature central receiver concentrated solar power plants with thermal energy storage.

    Energy Technology Data Exchange (ETDEWEB)

    Ehrhart, Brian David; Gill, David Dennis

    2013-07-01

    The current study has examined four cases of a central receiver concentrated solar power plant with thermal energy storage using the DELSOL and SOLERGY computer codes. The current state-of-the-art base case was compared with a theoretical high temperature case which was based on the scaling of some input parameters and the estimation of other parameters based on performance targets from the Department of Energy SunShot Initiative. This comparison was done for both current and high temperature cases in two configurations: a surround field with an external cylindrical receiver and a north field with a single cavity receiver. There is a fairly dramatic difference between the design point and annual average performance, especially in the solar field and receiver subsystems, and also in energy losses due to the thermal energy storage being full to capacity. Additionally, there are relatively small differences (<2%) in annual average efficiencies between the Base and High Temperature cases, despite an increase in thermal to electric conversion efficiency of over 8%. This is due the increased thermal losses at higher temperature and operational losses due to subsystem start-up and shut-down. Thermal energy storage can mitigate some of these losses by utilizing larger thermal energy storage to ensure that the electric power production system does not need to stop and re-start as often, but solar energy is inherently transient. Economic and cost considerations were not considered here, but will have a significant impact on solar thermal electric power production strategy and sizing.

  19. Solar Thermal Energy Technology

    Energy Technology Data Exchange (ETDEWEB)

    Cason, D.L.; Pitsenbarger, J. [eds.

    1996-02-01

    Solar Thermal Energy Technology (PST) announces on a bimonthly basis the current worldwide research and development information that would expand the technology base required for the advancement of solar thermal systems as a significant energy resource.

  20. Solar Thermal Energy; Energia Solar Termica

    Energy Technology Data Exchange (ETDEWEB)

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

    2008-07-01

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

  1. High-temperature ceramic heat exchanger element for a solar thermal receiver

    Science.gov (United States)

    Strumpf, H. J.; Kotchick, D. M.; Coombs, M. G.

    1982-01-01

    A study has been completed on the development of a high-temperature ceramic heat exchanger element to be integrated into a solar reciver producing heated air. A number of conceptual designs were developed for heat exchanger elements of differing configuration. These were evaluated with respect to thermal performance, pressure drop, structural integrity, and fabricability. The final design selection identified a finned ceramic shell as the most favorable concept. The ceramic shell is surrounded by a larger metallic shell. The flanges of the two shells are sealed to provide a leak-tight pressure vessel. The ceramic shell is fabricated by an innovative combination of slip casting the receiver walls and precision casting the heat transfer finned plates. The fins are bonded to the shell during firing. Fabrication of a one-half scale demonstrator ceramic receiver has been completed.

  2. A high temperature ceramic heat exchanger element for a solar thermal receiver

    Science.gov (United States)

    Strumpf, H. J.; Kotchick, D. M.; Coombs, M. G.

    1982-01-01

    The development of a high-temperature ceramic heat exchanger element to be integrated into a solar receiver producing heated air was studied. A number of conceptual designs were developed for heat exchanger elements of differing configuration. These were evaluated with respect to thermal performance, pressure drop, structural integrity, and fabricability. The final design selection identified a finned ceramic shell as the most favorable concept. The shell is surrounded by a larger metallic shell. The flanges of the two shells are sealed to provide a leak-tight pressure vessel. The ceramic shell is to be fabricated by a innovative combination of slip casting the receiver walls and precision casting the heat transfer finned plates. The fins are bonded to the shell during firing. The unit is sized to produce 2150 F air at 2.7 atm pressure, with a pressure drop of about 2 percent of the inlet pressure. This size is compatible with a solar collector providing a receiver input of 85 kw(th). Fabrication of a one-half scale demonstrator ceramic receiver was completed.

  3. High Temperature Latent Heat Thermal Energy Storage to Augment Solar Thermal Propulsion for Microsatellites

    Science.gov (United States)

    2015-08-30

    heat of fusion . In this work, boron is considered a long-term high performance solution and silicon is presented as a near term development target with... conceptual studies. However, there have been no thorough investigations due to the absence of existing research in addition to cost and schedule constraints...driven by a nuclear thermal energy source. Zubrin et al. proposed a “bi-modal” approach which modified an existing 40 kWe nuclear-thermionic reactor

  4. Exergy analysis of integrated photovoltaic thermal solar water heater under constant flow rate and constant collection temperature modes

    NARCIS (Netherlands)

    Tiwari, A.; Dubey, Swapnil; Sandhu, G.S.; Sodha, M.S.; Anwar, S.I.

    2009-01-01

    In this communication, an analytical expression for the water temperature of an integrated photovoltaic thermal solar (IPVTS) water heater under constant flow rate hot water withdrawal has been obtained. Analysis is based on basic energy balance for hybrid flat plate collector and storage tank,

  5. High-flux/high-temperature solar thermal conversion: technology development and advanced applications

    Directory of Open Access Journals (Sweden)

    Romero Manuel

    2016-01-01

    Full Text Available Solar Thermal Power Plants have generated in the last 10 years a dynamic market for renewable energy industry and a pro-active networking within R&D community worldwide. By end 2015, there are about 5 GW installed in the world, most of them still concentrated in only two countries, Spain and the US, though a rapid process of globalization is taking place in the last few years and now ambitious market deployment is starting in countries like South Africa, Chile, Saudi Arabia, India, United Arab Emirates or Morocco. Prices for electricity produced by today's plants fill the range from 12 to 16 c€/kWh and they are capital intensive with investments above 4000 €/kW, depending on the number of hours of thermal storage. The urgent need to speed up the learning curve, by moving forward to LCOE below 10 c€/kWh and the promotion of sun-to-fuel applications, is driving the R&D programmes. Both, industry and R&D community are accelerating the transformation by approaching high-flux/high-temperature technologies and promoting the integration with high-efficiency conversion systems.

  6. Single bi-temperature thermal storage tank for application in solar thermal plant

    Science.gov (United States)

    Litwin, Robert Zachary; Wait, David; Lancet, Robert T.

    2017-05-23

    Thermocline storage tanks for solar power systems are disclosed. A thermocline region is provided between hot and cold storage regions of a fluid within the storage tank cavity. One example storage tank includes spaced apart baffles fixed relative to the tank and arranged within the thermocline region to substantially physically separate the cavity into hot and cold storage regions. In another example, a flexible baffle separated the hot and cold storage regions and deflects as the thermocline region shifts to accommodate changing hot and cold volumes. In yet another example, a controller is configured to move a baffle within the thermocline region in response to flow rates from hot and cold pumps, which are used to pump the fluid.

  7. High Temperature Latent Heat Thermal Energy Storage to Augment Solar Thermal Propulsion for Microsatellites

    Science.gov (United States)

    2014-03-01

    assumptions of  iso thermal test sections  were inaccurate • Demonstrated shielding efficiency of approx.  55% with hand polished aluminum shields • Must...Calculations TWO IMPULSE ONE PERIGEE BURN ONE APOGEE BURN TIW > 0.01 .. ’• ’ \\ ’ ’ ’ • (!),/ LEO TO GEO 14000 ~ I!N < 17000 FPS TRIP TIME < DAY...I MULTI I MPU SE MORE THAN ONf PER I GEE BURNS AND PWRE THAN ON£ nlNSERTJON" BURNS NEAR FINAL APOGEE LEO TO GEO 14000 ~ /lV ~ 19200 FPS TRIP

  8. Typology of the Solar thermal facilities of low temperature; Tipologia de instalaciones solares termicas de baja temperatura

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2008-07-01

    The public interest by sustain ability and the governmental support are in the base of the great number of solar thermal collectors installed during the last years. In fact, the new 2006 Building Technical Code, Very responsible for this development on 2007, has provoked the appearance of new design instruments to guarantee in the collectors his energetic efficiency, his architectural integration, his durability and his maintenance. This article checks the different types of solar collectors of low temperate. (Author)

  9. By-Pass Diode Temperature Tests of a Solar Array Coupon under Space Thermal Environment Conditions

    Science.gov (United States)

    Wright, Kenneth H.; Schneider, Todd A.; Vaughn, Jason A.; Hoang, Bao; Wong, Frankie; Wu, Gordon

    2016-01-01

    By-Pass diodes are a key design feature of solar arrays and system design must be robust against local heating, especially with implementation of larger solar cells. By-Pass diode testing was performed to aid thermal model development for use in future array designs that utilize larger cell sizes that result in higher string currents. Testing was performed on a 56-cell Advanced Triple Junction solar array coupon provided by SSL. Test conditions were vacuum with cold array backside using discrete by-pass diode current steps of 0.25 A ranging from 0 A to 2.0 A.

  10. Concentrating solar thermal power.

    Science.gov (United States)

    Müller-Steinhagen, Hans

    2013-08-13

    In addition to wind and photovoltaic power, concentrating solar thermal power (CSP) will make a major contribution to electricity provision from renewable energies. Drawing on almost 30 years of operational experience in the multi-megawatt range, CSP is now a proven technology with a reliable cost and performance record. In conjunction with thermal energy storage, electricity can be provided according to demand. To date, solar thermal power plants with a total capacity of 1.3 GW are in operation worldwide, with an additional 2.3 GW under construction and 31.7 GW in advanced planning stage. Depending on the concentration factors, temperatures up to 1000°C can be reached to produce saturated or superheated steam for steam turbine cycles or compressed hot gas for gas turbine cycles. The heat rejected from these thermodynamic cycles can be used for sea water desalination, process heat and centralized provision of chilled water. While electricity generation from CSP plants is still more expensive than from wind turbines or photovoltaic panels, its independence from fluctuations and daily variation of wind speed and solar radiation provides it with a higher value. To become competitive with mid-load electricity from conventional power plants within the next 10-15 years, mass production of components, increased plant size and planning/operating experience will be accompanied by technological innovations. On 30 October 2009, a number of major industrial companies joined forces to establish the so-called DESERTEC Industry Initiative, which aims at providing by 2050 15 per cent of European electricity from renewable energy sources in North Africa, while at the same time securing energy, water, income and employment for this region. Solar thermal power plants are in the heart of this concept.

  11. The Effect of Solar Reflective Cover on Soak Air Temperature and Thermal Comfort of Car Parked under the Sun

    Directory of Open Access Journals (Sweden)

    Lahimer A.A.

    2017-01-01

    Full Text Available Parking a vehicle under the sun for a short period of time can rapidly increase the interior air cabin temperature no matter in clear sky days or even in partially cloudy days. These circumstances can be anxieties to car occupants upon entry. The aim of this paper is to evaluate experimentally the effect of solar reflective cover (SRC on vehicle air temperature and cabin thermal comfort. Experimental measurements of parked cars were conducted in UKM, Bangi city, Malaysia (latitude of 2.9° N and longitude of 101.78° E under partially cloudy day where average ambient temperature is 33°C. The experimental measurements cover the following cases: case (I: car with/ without SRC (at different measurement time; Case (II: using two identical cars concurrently (SRC versus baseline; Case (III: using two identical cars concurrently (solar reflective film (SRF versus baseline and Case (IV: using two identical cars concurrently (SRF versus SRC. Experimental results dedicated to case (I revealed that the maximum cabin air temperature with SRC (39.6°C is significantly lower than that of baseline case (57.3°C. This leads to temperature reduction improvement of 31% and the difference between the cabin and the ambient air temperature was minimized by approximately 73%. In addition, the results revealed that the air temperature at breath level of car with SRC dropped to comfort temperature (27°C after 7 min while baseline car reached comfort temperature after 14 min. Results of the other cases are discussed inside the paper. Overall, it is learned that SRC is found superior as an efficient thermal insulation system limits solar radiation transmission into the cabin through the glass; keeps cabin air temperature close to the ambient temperature; and provide acceptable thermal environment to the occupants as they settle into their parked car.

  12. The Effect of Solar Reflective Cover on Soak Air Temperature and Thermal Comfort of Car Parked under the Sun

    Science.gov (United States)

    Lahimer, A. A.; Alghoul, M. A.; Sopian, K.; Khrit, N. G.

    2017-11-01

    Parking a vehicle under the sun for a short period of time can rapidly increase the interior air cabin temperature no matter in clear sky days or even in partially cloudy days. These circumstances can be anxieties to car occupants upon entry. The aim of this paper is to evaluate experimentally the effect of solar reflective cover (SRC) on vehicle air temperature and cabin thermal comfort. Experimental measurements of parked cars were conducted in UKM, Bangi city, Malaysia (latitude of 2.9° N and longitude of 101.78° E) under partially cloudy day where average ambient temperature is 33°C. The experimental measurements cover the following cases: case (I): car with/ without SRC (at different measurement time); Case (II): using two identical cars concurrently (SRC versus baseline); Case (III): using two identical cars concurrently (solar reflective film (SRF) versus baseline) and Case (IV): using two identical cars concurrently (SRF versus SRC). Experimental results dedicated to case (I) revealed that the maximum cabin air temperature with SRC (39.6°C) is significantly lower than that of baseline case (57.3°C). This leads to temperature reduction improvement of 31% and the difference between the cabin and the ambient air temperature was minimized by approximately 73%. In addition, the results revealed that the air temperature at breath level of car with SRC dropped to comfort temperature (27°C) after 7 min while baseline car reached comfort temperature after 14 min. Results of the other cases are discussed inside the paper. Overall, it is learned that SRC is found superior as an efficient thermal insulation system limits solar radiation transmission into the cabin through the glass; keeps cabin air temperature close to the ambient temperature; and provide acceptable thermal environment to the occupants as they settle into their parked car.

  13. Solar Thermal Concept Evaluation

    Science.gov (United States)

    Hawk, Clark W.; Bonometti, Joseph A.

    1995-01-01

    Concentrated solar thermal energy can be utilized in a variety of high temperature applications for both terrestrial and space environments. In each application, knowledge of the collector and absorber's heat exchange interaction is required. To understand this coupled mechanism, various concentrator types and geometries, as well as, their relationship to the physical absorber mechanics were investigated. To conduct experimental tests various parts of a 5,000 watt, thermal concentrator, facility were made and evaluated. This was in anticipation at a larger NASA facility proposed for construction. Although much of the work centered on solar thermal propulsion for an upper stage (less than one pound thrust range), the information generated and the facility's capabilities are applicable to material processing, power generation and similar uses. The numerical calculations used to design the laboratory mirror and the procedure for evaluating other solar collectors are presented here. The mirror design is based on a hexagonal faceted system, which uses a spherical approximation to the parabolic surface. The work began with a few two dimensional estimates and continued with a full, three dimensional, numerical algorithm written in FORTRAN code. This was compared to a full geometry, ray trace program, BEAM 4, which optimizes the curvatures, based on purely optical considerations. Founded on numerical results, the characteristics of a faceted concentrator were construed. The numerical methodologies themselves were evaluated and categorized. As a result, the three-dimensional FORTRAN code was the method chosen to construct the mirrors, due to its overall accuracy and superior results to the ray trace program. This information is being used to fabricate and subsequently, laser map the actual mirror surfaces. Evaluation of concentrator mirrors, thermal applications and scaling the results of the 10 foot diameter mirror to a much larger concentrator, were studied. Evaluations

  14. Proof-of-Concept Testing of the Passive Cooling System (T-CLIP™) for Solar Thermal Applications at an Elevated Temperature

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Seung Jun [Los Alamos National Lab. (LANL), Los Alamos, NM (United States). Applied Engineering and Technology; Quintana, Donald L. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States). Applied Engineering and Technology; Vigil, Gabrielle M. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States). Applied Engineering and Technology; Perraglio, Martin Juan [Los Alamos National Lab. (LANL), Los Alamos, NM (United States). Applied Engineering and Technology; Farley, Cory Wayne [Los Alamos National Lab. (LANL), Los Alamos, NM (United States). Applied Engineering and Technology; Tafoya, Jose I. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States). Applied Engineering and Technology; Martinez, Adam L. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States). Applied Engineering and Technology

    2015-11-30

    The Applied Engineering and Technology-1 group (AET-1) at Los Alamos National Laboratory (LANL) conducted the proof-of-concept tests of SolarSPOT LLC’s solar thermal Temperature- Clipper, or T-CLIP™ under controlled thermal conditions using a thermal conditioning unit (TCU) and a custom made environmental chamber. The passive T-CLIP™ is a plumbing apparatus that attaches to a solar thermal collector to limit working fluid temperature and to prevent overheating, since overheating may lead to various accident scenarios. The goal of the current research was to evaluate the ability of the T-CLIP™ to control the working fluid temperature by using its passive cooling mechanism (i.e. thermosiphon, or natural circulation) in a small-scale solar thermal system. The assembled environmental chamber that is thermally controlled with the TCU allows one to simulate the various possible weather conditions, which the solar system will encounter. The performance of the T-CLIP™ was tested at two different target temperatures: 1) room temperature (70 °F) and 2) an elevated temperature (130 °F). The current test campaign demonstrated that the T-CLIP™ was able to prevent overheating by thermosiphon induced cooling in a small-scale solar thermal system. This is an important safety feature in situations where the pump is turned off due to malfunction or power outages.

  15. Selection of high temperature thermal energy storage materials for advanced solar dynamic space power systems

    Science.gov (United States)

    Lacy, Dovie E.; Coles-Hamilton, Carolyn; Juhasz, Albert

    1987-01-01

    Under the direction of NASA's Office of Aeronautics and Technology (OAST), the NASA Lewis Research Center has initiated an in-house thermal energy storage program to identify combinations of phase change thermal energy storage media for use with a Brayton and Stirling Advanced Solar Dynamic (ASD) space power system operating between 1070 and 1400 K. A study has been initiated to determine suitable combinations of thermal energy storage (TES) phase change materials (PCM) that result in the smallest and lightest weight ASD power system possible. To date the heats of fusion of several fluoride salt mixtures with melting points greater than 1025 K have been verified experimentally. The study has indicated that these salt systems produce large ASD systems because of their inherent low thermal conductivity and low density. It is desirable to have PCMs with high densities and high thermal conductivities. Therefore, alternate phase change materials based on metallic alloy systems are also being considered as possible TES candidates for future ASD space power systems.

  16. Eutectic mixtures of some fatty acids for low temperature solar heating applications: Thermal properties and thermal reliability

    Energy Technology Data Exchange (ETDEWEB)

    Sari, Ahmet [Department of Chemistry, Gaziosmanpasa University, 60240 Tokat (Turkey)]. E-mail: asari@gop.edu.tr

    2005-10-01

    The thermal properties and thermal reliability of the eutectic mixtures of lauric acid-myristic acid (LA-MA), lauric acid-palmitic acid (LA-PA), myristic acid-stearic acid (MA-SA) as phase change material (PCM) were determined after repeated melt/freeze cycles by the method of differential scanning calorimeter (DSC). The DSC thermal analysis results indicate that the binary systems of LA-MA in ratio of 66.0:34.0 wt.%, LA-PA in ratio of 69.0:31.0 wt.% and MA-SA in ratio of 64.0:36.0 wt.% form eutectic mixture with a melting temperature of 34.2 deg. C, 35.2 deg. C and 44.1 deg. C, and with a latent heat of fusion of 166.8 J g{sup -1}, 166.3 J g{sup -1} and 182.4 J g{sup -1}, respectively. The changes in the melting temperatures and the latent heats of fusion are in the range of -0.31 deg. C-0.14 deg. C and 0.9%-2.4% for LA-MA, -0.40 deg. C-0.23 deg. C and 1.5%-3.0% for LA-PA, and 1.11 deg. C-0.26 deg. C and -1.10%-2.2% for MA-SA during the 1460 thermal cycles. Based on the results, it can be concluded that the studied PCMs have good thermal properties and thermal reliability for a four-year energy storage period, which corresponds to 1460 thermal cycles, in terms of the change in their melting temperatures and latent heats of fusion.

  17. Development and Performance Evaluation of High Temperature Concrete for Thermal Energy Storage for Solar Power Generation

    Energy Technology Data Exchange (ETDEWEB)

    Selvam, R. Panneer; Hale, Micah; Strasser, Matt

    2013-03-31

    Thermal energy can be stored by the mechanism of sensible or latent heat or heat from chemical reactions. Sensible heat is the means of storing energy by increasing the temperature of the solid or liquid. Since the concrete as media cost per kWhthermal is $1, this seems to be a very economical material to be used as a TES. This research is focused on extending the concrete TES system for higher temperatures (500 °C to 600 °C) and increasing the heat transfer performance using novel construction techniques. To store heat at high temperature special concretes are developed and tested for its performance. The storage capacity costs of the developed concrete is in the range of $0.91-$3.02/kWhthermal. Two different storage methods are investigated. In the first one heat is transported using molten slat through a stainless steel tube and heat is transported into concrete block through diffusion. The cost of the system is higher than the targeted DOE goal of $15/kWhthermal. The increase in cost of the system is due to stainless steel tube to transfer the heat from molten salt to the concrete blocks.The other method is a one-tank thermocline system in which both the hot and cold fluid occupy the same tank resulting in reduced storage tank volume. In this model, heated molten salt enters the top of the tank which contains a packed bed of quartzite rock and silica sand as the thermal energy storage (TES) medium. The single-tank storage system uses about half the salt that is required by the two-tank system for a required storage capacity. This amounts to a significant reduction in the cost of the storage system. The single tank alternative has also been proven to be cheaper than the option which uses large concrete modules with embedded heat exchangers. Using computer models optimum dimensions are determined to have an round trip efficiency of 84%. Additionally, the cost of the structured concrete thermocline configuration provides the TES

  18. Solar thermal conversion

    Science.gov (United States)

    Selcuk, M. K.

    1978-01-01

    A brief review of the fundamentals of the conversion of solar energy into mechanical work (or electricity via generators) is given. Both past and present work on several conversion concepts are discussed. Solar collectors, storage systems, energy transport, and various types of engines are examined. Ongoing work on novel concepts of collectors, energy storage and thermal energy conversion are outlined and projections for the future are described. Energy costs for various options are predicted and margins and limitations are discussed.

  19. Solar thermal financing guidebook

    Energy Technology Data Exchange (ETDEWEB)

    Williams, T.A.; Cole, R.J.; Brown, D.R.; Dirks, J.A.; Edelhertz, H.; Holmlund, I.; Malhotra, S.; Smith, S.A.; Sommers, P.; Willke, T.L.

    1983-05-01

    This guidebook contains information on alternative financing methods that could be used to develop solar thermal systems. The financing arrangements discussed include several lease alternatives, joint venture financing, R and D partnerships, industrial revenue bonds, and ordinary sales. In many situations, alternative financing arrangements can significantly enhance the economic attractiveness of solar thermal investments by providing a means to efficiently allocate elements of risk, return on investment, required capital investment, and tax benefits. A net present value approach is an appropriate method that can be used to investigate the economic attractiveness of alternative financing methods. Although other methods are applicable, the net present value approach has advantages of accounting for the time value of money, yielding a single valued solution to the financial analysis, focusing attention on the opportunity cost of capital, and being a commonly understood concept that is relatively simple to apply. A personal computer model for quickly assessing the present value of investments in solar thermal plants with alternative financing methods is presented in this guidebook. General types of financing arrangements that may be desirable for an individual can be chosen based on an assessment of his goals in investing in solar thermal systems and knowledge of the individual's tax situation. Once general financing arrangements have been selected, a screening analysis can quickly determine if the solar investment is worthy of detailed study.

  20. Solar Thermal Power.

    Science.gov (United States)

    McDaniels, David K.

    The different approaches to the generation of power from solar energy may be roughly divided into five categories: distributed collectors; central receivers; biomass; ocean thermal energy conversion; and photovoltaic devices. The first approach (distributed collectors) is the subject of this module. The material presented is designed to…

  1. Solar thermal technology

    Science.gov (United States)

    1988-09-01

    This annual report describes the accomplishments and progress of government-funded activities initiated, renewed, or completed during Fiscal Year (FY) 1987 (October 1, 1986, through September 30, 1987). It highlights the program tasks conducted by participating federal laboratories and by industrial, academic, or other research under a subcontract. The emphasis of the Solar Thermal Technology Program during the year was: (1) to perform research and development leading to the economic viability of two primary solar thermal concepts, central receiver and parabolic dish, and (2) to explore applications of national significance where the special attributes of concentrated sunlight are appropriate. The report includes three appendices that cover principal contacts and sources of additional information (Appendix A), acronyms and abbreviations (Appendix B), and a glossary of terms (Appendix C). A bibliography of relevant publications from Sandia National Laboratories and the Solar Energy Research Institute completes this annual report.

  2. Scattering Solar Thermal Concentrators

    Energy Technology Data Exchange (ETDEWEB)

    Giebink, Noel C. [Pennsylvania State Univ., State College, PA (United States)

    2015-01-31

    concentrator optical efficiency was found to decrease significantly with increasing aperture width beyond 0.5 m due to parasitic waveguide out-coupling loss and low-level absorption that become dominant at larger scale. A heat transfer model was subsequently implemented to predict collector fluid heat gain and outlet temperature as a function of flow rate using the optical model as a flux input. It was found that the aperture width size limitation imposed by the optical efficiency characteristics of the waveguide limits the absolute optical power delivered to the heat transfer element per unit length. As compared to state-of-the-art parabolic trough CPV system aperture widths approaching 5 m, this limitation leads to an approximate factor of order of magnitude increase in heat transfer tube length to achieve the same heat transfer fluid outlet temperature. The conclusion of this work is that scattering solar thermal concentration cannot be implemented at the scale and efficiency required to compete with the performance of current parabolic trough CSP systems. Applied within the alternate context of CPV, however, the results of this work have likely opened up a transformative new path that enables quasi-static, high efficiency CPV to be implemented on rooftops in the form factor of traditional fixed-panel photovoltaics.

  3. Solar engineering of thermal processes

    CERN Document Server

    Duffie, John A

    2013-01-01

    The updated fourth edition of the ""bible"" of solar energy theory and applications Over several editions, Solar Engineering of Thermal Processes has become a classic solar engineering text and reference. This revised Fourth Edition offers current coverage of solar energy theory, systems design, and applications in different market sectors along with an emphasis on solar system design and analysis using simulations to help readers translate theory into practice. An important resource for students of solar engineering, solar energy, and alternative energy as well

  4. Analysis of the Thermal Stress for Combined Electrode of Soldered Crystalline Silicon Solar Cells under Temperature Field

    Directory of Open Access Journals (Sweden)

    He Wang

    2016-01-01

    Full Text Available Based on the theory of material mechanics and thermal stress analysis, the stress distribution of combined electrode for crystalline silicon solar module was studied for the first time. The shear stress and normal stress distribution of soldered structure for crystalline silicon solar cells under the thermal field were discussed. And the results show that the stress distribution is not simply linear relationship as some results found. But there is a stress concentration at the edge, which was considered as the true reason that caused microcracks at the edge of soldered solar cells. The conclusions we got in this paper provide a theoretical basis for deceasing the breakage rates of soldered crystalline silicon solar cells and improving the reliability of crystalline silicon solar modules.

  5. Solar thermal power system

    Science.gov (United States)

    Bennett, Charles L.

    2010-06-15

    A solar thermal power generator includes an inclined elongated boiler tube positioned in the focus of a solar concentrator for generating steam from water. The boiler tube is connected at one end to receive water from a pressure vessel as well as connected at an opposite end to return steam back to the vessel in a fluidic circuit arrangement that stores energy in the form of heated water in the pressure vessel. An expander, condenser, and reservoir are also connected in series to respectively produce work using the steam passed either directly (above a water line in the vessel) or indirectly (below a water line in the vessel) through the pressure vessel, condense the expanded steam, and collect the condensed water. The reservoir also supplies the collected water back to the pressure vessel at the end of a diurnal cycle when the vessel is sufficiently depressurized, so that the system is reset to repeat the cycle the following day. The circuital arrangement of the boiler tube and the pressure vessel operates to dampen flow instabilities in the boiler tube, damp out the effects of solar transients, and provide thermal energy storage which enables time shifting of power generation to better align with the higher demand for energy during peak energy usage periods.

  6. Survey of Properties of Key Single and Mixture Halide Salts for Potential Application as High Temperature Heat Transfer Fluids for Concentrated Solar Thermal Power Systems

    Directory of Open Access Journals (Sweden)

    Chao-Jen Li

    2014-04-01

    Full Text Available In order to obtain high energy efficiency in a concentrated solar thermal power plant, more and more high concentration ratio to solar radiation are applied to collect high temperature thermal energy in modern solar power technologies. This incurs the need of a heat transfer fluid being able to work at more and more high temperatures to carry the heat from solar concentrators to a power plant. To develop the third generation heat transfer fluids targeting at a high working temperature at least 800 ℃, a research team from University of Arizona, Georgia Institute of Technology, and Arizona State University proposed to use eutectic halide salts mixtures in order to obtain the desired properties of low melting point, low vapor pressure, great stability at temperatures at least 800 ℃, low corrosion, and favorable thermal and transport properties. In this paper, a survey of the available thermal and transport properties of single and eutectic mixture of several key halide salts is conducted, providing information of great significance to researchers for heat transfer fluid development.

  7. High-temperature stable absorber coatings for linear concentrating solar thermal power plants; Hochtemperaturstabile Absorberschichten fuer linear konzentrierende solarthermische Kraftwerke

    Energy Technology Data Exchange (ETDEWEB)

    Hildebrandt, Christina

    2009-03-23

    This work describes the development of new absorber coatings for different applications - para-bolic trough and linear Fresnel collectors - and operating conditions - absorber in vacuum or in air. The demand for higher efficiencies of solar thermal power plants using parabolic trough technology results in higher temperatures in the collectors and on the absorber tubes. As heat losses increase strongly with increasing temperatures, the need for a lower emissivity of the absorber coating at constant absorptivity arises. The linear Fresnel application envisions ab-sorber tubes stable in air at high temperatures of about 450 C, which are to date commercially not available. This work comprises the theoretical background, the modeling and the fabrication of absorber tubes including the technology transfer to a production-size inline sputter coater. In annealing tests and accompanying optical measurements, degradation processes have been observed and specified more precisely by material characterization techniques. The simulations provided the capability of different materials used as potential IR-reflector. The highest selectivity can be achieved by applying silver which consequently has been chosen for the application in absorber coatings of the parabolic trough technology. Thin silver films how-ever need to be stabilized when used at high temperatures. Appropriate barrier layers as well as process and layer parameters were identified. A high selectivity was achieved and stability of the absorber coating for 1200 h at 500 C in vacuum has been demonstrated. For the application in air, silver was also analyzed as a potential IR-reflector. Even though the stability could be increased considerably, it nevertheless proved to be insufficient. The main factors influencing stability in a positive way are the use of higher quality polishing, additional barrier layers and adequate process parameters. This knowledge was applied for developing coatings which are stable in air at

  8. Concentrated solar thermal power - Now

    Energy Technology Data Exchange (ETDEWEB)

    Aringhoff, R.; Brakmann, G. [Solar Thermal Power Industry Association ESTIA, Avenue de la Fauconnerie 73, 1170 Brussels (Belgium); Geyer, M. [IEA SolarPACES Implementing Agreement, Avenida de la Paz 51, 04720 Aguadulce, Almeria (Spain); Teske, S. [Greenpeace International, Ottho Heldringstraat 5, 1066 AZ Amsterdam (Netherlands)

    2005-09-15

    This report demonstrates that there are no technical, economic or resource barriers to supplying 5% of the world's electricity needs from solar thermal power by 2040. It is written as practical blueprint to improve understanding of the solar thermal contribution to the world energy supply.

  9. A numerical study of transient, thermally-conductive solar wind

    Science.gov (United States)

    Han, S. M.; Wu, S. T.; Dryer, M.

    1987-01-01

    A numerical analysis of transient solar wind starting at the solar surface and arriving at 1 AU is performed by an implicit numerical method. The model hydrodynamic equations include thermal conduction terms for both steady and unsteady simulations. Simulation results show significant influence of thermal conduction on both steady and time-dependent solar wind. Higher thermal conduction results in higher solar wind speed, higher temperature, but lower plasma density at 1 AU. Higher base temperature at the solar surface gives lower plasma speed, lower temperature, but higher density at 1 AU. Higher base density, on the other hand, gives lower velocity, lower temperature, but higher density at 1 AU.

  10. Parametric analysis of a high temperature packed bed thermal storage design for a solar gas turbine

    CSIR Research Space (South Africa)

    Klein, P

    2015-08-01

    Full Text Available , conductive and radiative heat transfer mechanisms and is validated against high temperature experimental data from a laboratory scale test facility. The validated model is further utilised to conduct a parametric design study of a nominal six hour TES (1:55MW...

  11. Thermal Efficiency of Natural Convection Solar Dryer

    Science.gov (United States)

    Seetapong, N.; Chulok, S.; Khoonphunnarai, P.

    2017-09-01

    The purpose of this research is to study the thermal efficiency of natural convection. The working principle of natural convection solar dryer is, once the air in the solar dryer is heated by solar energy, the air relative humidity will drop and floating up through the drying. This air will take moisture out of the product and flow out to the ambient air. It was found from the experiment that, in the duration of 8.00 am - 4.00 pm on a clear sky day, an all-day average ambient air and inside the chamber temperature were 38.34°C and 63.19°C respectively. At the solar radiation intensity of 759.53W/m2, mass flow rate of air was 0.023 kg/s and the thermal efficiency of the solar dryer was 2.59%.

  12. National Solar Thermal Test Facility

    Data.gov (United States)

    Federal Laboratory Consortium — The National Solar Thermal Test Facility (NSTTF) is the only test facility in the United States of its type. This unique facility provides experimental engineering...

  13. Effects of High Temperature and Thermal Cycling on the Performance of Perovskite Solar Cells: Acceleration of Charge Recombination and Deterioration of Charge Extraction.

    Science.gov (United States)

    Sheikh, Arif D; Munir, Rahim; Haque, Md Azimul; Bera, Ashok; Hu, Weijin; Shaikh, Parvez; Amassian, Aram; Wu, Tom

    2017-10-11

    In this work, we investigated the effects of high operating temperature and thermal cycling on the photovoltaic (PV) performance of perovskite solar cells (PSCs) with a typical mesostructured (m)-TiO2-CH3NH3PbI3-xClx-spiro-OMeTAD architecture. After temperature-dependent grazing-incidence wide-angle X-ray scattering, in situ X-ray diffraction, and optical absorption experiments were carried out, the thermal durability of PSCs was tested by subjecting the devices to repetitive heating to 70 °C and cooling to room temperature (20 °C). An unexpected regenerative effect was observed after the first thermal cycle; the average power conversion efficiency (PCE) increased by approximately 10% in reference to the as-prepared device. This increase of PCE was attributed to the heating-induced improvement of the crystallinity and p doping in the hole transporter, spiro-OMeTAD, which promotes the efficient extraction of photogenerated carriers. However, further thermal cycles produced a detrimental effect on the PV performance of PSCs, with the short-circuit current and fill factor degrading faster than the open-circuit voltage. Similarly, the PV performance of PSCs degraded at high operation temperatures; both the short-circuit current and open-circuit voltage decreased with increasing temperature, but the temperature-dependent trend of the fill factor was the opposite. Our impedance spectroscopy analysis revealed a monotonous increase of the charge-transfer resistance and a concurrent decrease of the charge-recombination resistance with increasing temperature, indicating a high recombination of charge carriers. Our results revealed that both thermal cycling and high temperatures produce irreversible detrimental effects on the PSC performance because of the deteriorated interfacial photocarrier extraction. The present findings suggest that the development of robust charge transporters and proper interface engineering are critical for the deployment of perovskite PVs in harsh

  14. Effects of High Temperature and Thermal Cycling on the Performance of Perovskite Solar Cells: Acceleration of Charge Recombination and Deterioration of Charge Extraction

    KAUST Repository

    Sheikh, Arif D.

    2017-09-18

    In this work, we investigated the effects of high operating temperature and thermal cycling on the photovoltaic performance of perovskite solar cells (PSCs) with a typical mesostructured (m)-TiO2-CH3NH3PbI3-xClx-spiro-OMeTAD architecture. After carrying out temperature-dependent grazing incidence wide-angle X-ray scattering (GIWAXS), in-situ X-ray diffraction (XRD) and optical absorption experiments, thermal durability of PSCs was tested by subjecting the devices to repetitive heating to 70 °C and cooling to room temperature (20 °C). An unexpected regenerative effect was observed after the first thermal cycle; the average power conversion efficiency (PCE) increased by approximately 10 % in reference to the as-prepared device. This increase of PCE was attributed to the heating-induced improvement of crystallinity and p-doping in the hole-transporter, Spiro-OMeTAD, which promotes the efficient extraction of photo-generated carriers. However, further thermal cycles produced a detrimental effect on the photovoltaic performance of PSCs with short-circuit current and fill factor degrading faster than the open-circuit voltage. Similarly, the photovoltaic performance of PSCs degraded at high operation temperatures; both short-circuit current and open-circuit voltage decreased with increasing temperature, but the temperature-dependent trend of fill factor was opposite. Our impedance spectroscopy analysis revealed a monotonous increase of charge transfer resistance and a concurrent decrease of charge recombination resistance with increasing temperature, indicating high recombination of charge carriers. Our results revealed that both thermal cycling and high temperatures produce irreversible detrimental effects on the PSC performance due to the deteriorated interfacial photo-carrier extraction. The present findings suggest that development of robust charge transporters and proper interface engineering are critical for the deployment of perovskite photovoltaics in harsh

  15. Thermal Performance of an Annealed Pyrolytic Graphite Solar Collector

    Science.gov (United States)

    Jaworske, Donald A.; Hornacek, Jennifer

    2002-01-01

    A solar collector having the combined properties of high solar absorptance, low infrared emittance, and high thermal conductivity is needed for applications where solar energy is to be absorbed and transported for use in minisatellites. Such a solar collector may be used with a low temperature differential heat engine to provide power or with a thermal bus for thermal switching applications. One concept being considered for the solar collector is an Al2O3 cermet coating applied to a thermal conductivity enhanced polished aluminum substrate. The cermet coating provides high solar absorptance and the polished aluminum provides low infrared emittance. Annealed pyrolytic graphite embedded in the aluminum substrate provides enhanced thermal conductivity. The as-measured thermal performance of an annealed pyrolytic graphite thermal conductivity enhanced polished aluminum solar collector, coated with a cermet coating, will be presented.

  16. Solar thermal production of zinc: Program strategy

    Energy Technology Data Exchange (ETDEWEB)

    Steinfeld, A.; Weidenkaff, A.; Moeller, S.; Palumbo, R. [Paul Scherrer Inst. (PSI), Villigen (Switzerland)

    1999-08-01

    The solar thermal production of zinc is considered for the conversion of solar energy into storable and transportable chemical fuels. The ultimate objective is to develop a technically and economically viable technology that can produce solar zinc. The program strategy for achieving such a goal involves research on two paths: a direct path via the solar thermal splitting of ZnO in the absence of fossil fuels, and an indirect path via the solar carbothermal/CH{sub 4}-thermal reduction of Zn O, with fossil fuels (coke or natural gas) as chemical reducing agents. Both paths make use of concentrated solar energy for high-temperature process heat. The direct path brings us to the complete substitution of fossil fuels with solar fuels for a sustainable energy supply system. The indirect path creates a link between today`s fossil-fuel-based technology and tomorrow`s solar chemical technology and builds bridges between present and future energy economies. (author) 1 fig., 15 refs.

  17. The Application of Thermal Solar Energy to High Temperature Processes: Case Study of the Synthesis of Alumina from Boehmite

    Directory of Open Access Journals (Sweden)

    Isabel Padilla

    2014-01-01

    Full Text Available The aim of this paper is to evaluate the feasibility of obtaining alumina from boehmite using a free, clean, and unlimited power source as the solar energy. Boehmite was obtained by hydrothermal treatment of a hazardous waste coming from aluminum slag milling. The waste is considered as a hazardous substance because of it releasing toxic gases (hydrogen, ammonia, methane, and hydrogen sulfide in the presence of water. The as-obtained boehmite was transformed into alumina, in air atmosphere, using a solar energy concentrator (Fresnel lens. The solar installation provides a power density of 260 W·cm−2 which allows reaching temperatures upper than 1000°C at few minutes of exposure. Tests were performed at different periods of time that ranged between 5 and 90 min. The percentage of transformation of boehmite into alumina was followed by the water content of samples after solar radiation exposure. Samples were characterized by X-ray diffraction, infrared spectroscopy, and thermogravimetry. Metastable aluminas started to appear at 5 min and the crystalline and stable phase corundum at 10 min of solar radiation exposure.

  18. Components of solar thermal systems

    OpenAIRE

    Mendes, J. Farinha; Carvalho, M.J.; Schossig, Peter

    2013-01-01

    The heat production sub-system is the part of the overall system which provides heat to a thermally driven air-conditioning system. With regards to the solar-driven equipment, the solar collector is the main component of the sub-system. A brief review on the present state-of-the-art with respect to performance characteristics and available certification schemes of solar collectors is given in the following chapter. Besides the solar collector field, the storage unit and the back-up heat sourc...

  19. PV-enhanced solar thermal power

    OpenAIRE

    Platzer, W.

    2014-01-01

    Solar electricity generation using concentrating solar thermal collectors faces the challenge of strongly decreased levelized electricity costs by photovoltaic power plants. One of the selling points favouring solar thermal power is the possibility to generate dispatchable power. Concepts discussed here are solar hybridization of conventional or biomass thermal power plants. Another option is the use of thermal energy storage (TES) charged with solar heat which allow to drive the generation o...

  20. Drainback solar thermal systems

    DEFF Research Database (Denmark)

    Botpaev, R.; Louvet, Y.; Perers, Bengt

    2016-01-01

    Although solar drainback systems have been used for a long time, they are still generating questions regarding smooth functioning. This paper summarises publications on drainback systems and compiles the current knowledge, experiences, and ideas on the technology. The collective research exhibits...... of this technology has been developed, with a brief description of each hydraulic typology. The operating modes have been split into three stages: filling, operation, and draining, which have been studied separately. A difference in the minimal filling velocities for a siphon development in the solar loop has been...

  1. Drainback solar thermal systems

    DEFF Research Database (Denmark)

    Botpaev, R.; Louvet, Y.; Perers, Bengt

    2016-01-01

    Although solar drainback systems have been used for a long time, they are still generating questions regarding smooth functioning. This paper summarises publications on drainback systems and compiles the current knowledge, experiences, and ideas on the technology. The collective research exhibits...

  2. Solar thermal roofs; Zonthermische daken

    Energy Technology Data Exchange (ETDEWEB)

    Van de Waerdt, J. [DWA installatie- en energieadvies, Bodegraven (Netherlands)

    2012-11-15

    The purpose of the brochure is to increase the effective application of solar thermal roofs. The target group includes consultants, installers, architects and contractors. Attention is paid to the design, parameters for comparison, yield simulations and experiences gained in projects [Dutch] Het doel van de brochure is het vergroten van de effectieve toepassing van zonthermische daken. Tot de doelgroep behoren installatieadviseurs, installateurs, architecten en opdrachtgevers in de bouw. Aandacht wordt besteed aan het ontwerp, parameters voor vergelijking, opbrengstsimulaties en ervaringen opgedaan in projecten.

  3. Effects of radiant temperature on thermal comfort

    Energy Technology Data Exchange (ETDEWEB)

    Atmaca, Ibrahim; Kaynakli, Omer; Yigit, Abdulvahap [Uludag University, Bursa (Turkey). Faculty of Engineering and Architecture, Department of Mechanical Engineering

    2007-09-15

    The aim of this paper is to investigate the local differences between body segments caused by high radiant temperature, and to analyze the interior surface temperatures for different wall and ceiling constructions with their effect on thermal comfort. For the segment-wise thermal interactions between human body and its surrounding, simulations have been conducted by appropriately modifying Gagge 2-node model to multi-segment case to demonstrate the local differences. Simulation results are found to be in good agreement with experimental and simulation results reported in the literature. To calculate the interior surface temperatures of the wall and ceiling, the sol-air temperature approach is used for convenience. It is shown in the paper that the body segments close the relatively hot surfaces are more affected than others and interior surface temperatures of un-insulated walls and ceilings exposed to a strong solar radiation reach high levels, all of which cause thermal discomfort for the occupants in buildings. (author)

  4. Thermally-induced structural motions of satellite solar arrays

    Science.gov (United States)

    Johnston, John Dennis

    1999-11-01

    Satellites have experienced attitude disturbances resulting from thermally. induced structural motions of flexible appendages since the early days of the space program. Thermally-induced structural motions are typically initiated during orbital eclipse transitions when a satellite exits from or enters into the Earth's shadow. The accompanying rapid changes in thermal loading may lead to time-varying temperature differences through the cross-section of appendages resulting in differential thermal expansion and corresponding structural deformations. Since the total angular momentum of the system must be conserved, motions of flexible appendages such as booms and solar arrays result in rigid body rotations of the entire satellite. These potentially large attitude disturbances may violate satellite pointing and jitter requirements. This research investigates thermally-induced structural motions of rigid panel solar arrays (solar panels) through analytical and experimental studies. Orbital eclipse transition heating and thermal analyses were completed to study solar panel thermal behavior and provide results for input to dynamics analyses. A hybrid coordinate dynamical model was utilized to study the planar dynamics of a simple satellite consisting of a rigid hub with a cantilevered flexible solar panel undergoing thermally-induced structural motions. Laboratory experimental studies were carried out to gain new insight into thermal-structural behavior and to validate analytical models. The experimental studies investigated the thermal-structural performance of honeycomb sandwich panels and satellite solar panel hardware subject to simulated eclipse transition heating. Results from the analytical and experimental studies illustrate the importance of the through-the-thickness temperature difference and its time derivatives as well as the ratio of the characteristic thermal and structural response times in solar panel thermally-induced structural motions. The thermal

  5. Solar energy thermalization and storage device

    Science.gov (United States)

    McClelland, J.F.

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

  6. Better Thermal Insulation in Solar-Array Laminators

    Science.gov (United States)

    Burger, D. R.; Knox, J. F.

    1984-01-01

    Glass marbles improve temperature control. Modified vacuum laminator for photovoltaic solar arrays includes thermal insulation made of conventional glass marbles. Marbles serve as insulation for temperature control of lamination process at cure temperatures as high as 350 degrees F. Used to replace original insulation made of asbestos cement.

  7. Control Optimization of Solar Thermally Driven Chillers

    Directory of Open Access Journals (Sweden)

    Antoine Dalibard

    2016-10-01

    Full Text Available Many installed solar thermally driven cooling systems suffer from high auxiliary electric energy consumption which makes them not more efficient than conventional compression cooling systems. A main reason for this is the use of non-efficient controls with constant set points that do not allow a chiller power modulation at partial-load and therefore lead to unnecessary high power consumption of the parasitics. The aims of this paper are to present a method to control efficiently solar thermally driven chillers, to demonstrate experimentally its applicability and to quantify the benefits. It has been shown that the cooling capacity of a diffusion absorption chiller can be modulated very effectively by adjusting both the temperature and the flow rate of the cooling water. With the developed approach and the use of optimization algorithms, both the temperature and the flow rate can be controlled simultaneously in a way that the cooling load is matched and the electricity consumption is minimized. Depending on the weather and operating conditions, electricity savings between 20% and 60% can be achieved compared to other tested control approaches. The highest savings are obtained when the chiller is operated at partial load. The presented method is not restricted to solar cooling systems and can also be applied to other conventional heating ventilation and air conditioning (HVAC systems.

  8. Polymeric materials for solar thermal applications

    CERN Document Server

    Köhl, Michael; Papillon, Philippe; Wallner, Gernot M; Saile, Sandrin

    2012-01-01

    Bridging the gap between basic science and technological applications, this is the first book devoted to polymers for solar thermal applications.Clearly divided into three major parts, the contributions are written by experts on solar thermal applications and polymer scientists alike. The first part explains the fundamentals of solar thermal energy especially for representatives of the plastics industry and researchers. Part two then goes on to provide introductory information on polymeric materials and processing for solar thermal experts. The third part combines both of these fields, dis

  9. Solar panel thermal cycling testing by solar simulation and infrared radiation methods

    Science.gov (United States)

    Nuss, H. E.

    1980-01-01

    For the solar panels of the European Space Agency (ESA) satellites OTS/MAROTS and ECS/MARECS the thermal cycling tests were performed by using solar simulation methods. The performance data of two different solar simulators used and the thermal test results are described. The solar simulation thermal cycling tests for the ECS/MARECS solar panels were carried out with the aid of a rotatable multipanel test rig by which simultaneous testing of three solar panels was possible. As an alternative thermal test method, the capability of an infrared radiation method was studied and infrared simulation tests for the ultralight panel and the INTELSAT 5 solar panels were performed. The setup and the characteristics of the infrared radiation unit using a quartz lamp array of approx. 15 sq and LN2-cooled shutter and the thermal test results are presented. The irradiation uniformity, the solar panel temperature distribution, temperature changing rates for both test methods are compared. Results indicate the infrared simulation is an effective solar panel thermal testing method.

  10. Solar engineering of thermal processes

    Science.gov (United States)

    Duffie, J. A.; Beckman, W. A.

    The book focuses on solar radiation characteristics, solar radiation available for practical applications, heat transfer, radiation characteristics of opaque materials, theory of flat-plate collectors, and concentrating collectors. Also discussed are solar process economics, solar water heating, solar heating system design, solar cooling, conversion to mechanical energy, evaporative processes, and selfgradient ponds.

  11. Pv-Thermal Solar Power Assembly

    Science.gov (United States)

    Ansley, Jeffrey H.; Botkin, Jonathan D.; Dinwoodie, Thomas L.

    2001-10-02

    A flexible solar power assembly includes a flexible photovoltaic device attached to a flexible thermal solar collector. The solar power assembly can be rolled up for transport and then unrolled for installation on a surface, such as the roof or side wall of a building or other structure, by use of adhesive and/or other types of fasteners.

  12. Development of a solar thermal thruster system

    NARCIS (Netherlands)

    Leenders, H.C.M.; Zandbergen, B.T.C.

    2008-01-01

    At the Delft University of Technology the use of solar radiation to heat a propellant to a high temperature is investigated as an alternative to resistance heating. The latter only allows for a solar power to heat conversion efficiency of about 25%, depending on the solar cells, whereas for solar

  13. Thermal performance analysis of a solar heating plant

    DEFF Research Database (Denmark)

    Fan, Jianhua; Huang, Junpeng; Andersen, Ola Lie

    Detailed measurements were carried out on a large scale solar heating plant located in southern Denmark in order to evaluate thermal performances of the plant. Based on the measurements, energy flows of the plant were evaluated. A modified Trnsys model of the Marstal solar heating plant...... was developed to calculate thermal performances of the plant. In the Trnsys model, three solar collector fields with a total solar collector area of 33,300 m2, a seasonal water pit heat storage of 75,000 m3, a simplified CO2 HP, a simplified ORC unit and a simplified wood chip boiler were included. The energy...... consumption of the district heating net was modeled by volume flow rate and given forward and return temperatures of the district heating net. Weather data from a weather station at the site of the plant were used in the calculations. The Trnsys calculated yearly thermal performance of the solar heating plant...

  14. Engine Optimization for a Solar Thermal Powered Orbit Transfer Vehicle

    Science.gov (United States)

    1998-06-01

    Recent technological advancements in solar thermal rocket propulsion and solar orbit transfer vehicles make it critical to perform additional engine performance analyses. Several system level flight demonstrations are imminent. Space flight hardware component testing is being conducted at the Air Force Research Laboratory, Edwards AFB, California. The focus of current research is engine and nozzle configurations for a solar orbit transfer vehicle. The optimal design must produce 1-10 pounds thrust, perform at high lsp and be compatible in a hybrid of spiral, perigee, and apogee (multi-burn) configurations. The nozzle material must not ablate when subjected to extreme thermal loading, yet be durable enough to withstand widely varying temperature differentials during frequent thermal cycling. This paper addresses propulsive needs in the orbit transfer arena and defines governing upper stage vehicle engine equations. These equations are modified versions of rocket engine equations used for chemical systems. The correction factors and modifications are for Solar Thermal Propulsion specific hardware.

  15. TEMPERATURE DEPENDENCE OF THE THERMAL ...

    African Journals Online (AJOL)

    Thermal conductivity values, in the temperature range 300 – 1200 K, have been measured in air and at atmospheric pressure for a Kenyan kaolinite refractory with 0% - 50% grog proportions. The experimental thermal conductivity values were then compared with those calculated using the Zumbrunnen et al [1] and the ...

  16. Semiconductor-based Multilayer Selective Solar Absorber for Unconcentrated Solar Thermal Energy Conversion.

    Science.gov (United States)

    Thomas, Nathan H; Chen, Zhen; Fan, Shanhui; Minnich, Austin J

    2017-07-13

    Solar thermal energy conversion has attracted substantial renewed interest due to its applications in industrial heating, air conditioning, and electricity generation. Achieving stagnation temperatures exceeding 200 °C, pertinent to these technologies, with unconcentrated sunlight requires spectrally selective absorbers with exceptionally low emissivity in the thermal wavelength range and high visible absorptivity for the solar spectrum. In this Communication, we report a semiconductor-based multilayer selective absorber that exploits the sharp drop in optical absorption at the bandgap energy to achieve a measured absorptance of 76% at solar wavelengths and a low emittance of approximately 5% at thermal wavelengths. In field tests, we obtain a peak temperature of 225 °C, comparable to that achieved with state-of-the-art selective surfaces. With straightforward optimization to improve solar absorption, our work shows the potential for unconcentrated solar thermal systems to reach stagnation temperatures exceeding 300 °C, thereby eliminating the need for solar concentrators for mid-temperature solar applications such as supplying process heat.

  17. Solar thermal systems successful planning and construction

    CERN Document Server

    Peuser, Dr Felix A; Schnauss, Martin

    2013-01-01

    Solar Thermal Systems summarizes the theoretical and practical knowledge gained from over 20 years of research, implementation and operation of thermal solar installations. This work provides answers to a variety of key questions by examining current solar installations, drawing upon past experiences and making proposals for future planning.- how do system components and materials behave under continuous operation?- which components have proven themselves and how are they used properly?- what are the causes of defects and how can they be avoided?- how long is the service life of modern solar i

  18. Mathematical model for thermal solar collectors by using magnetohydrodynamic Maxwell nanofluid with slip conditions, thermal radiation and variable thermal conductivity

    Science.gov (United States)

    Mahmood, Asif; Aziz, Asim; Jamshed, Wasim; Hussain, Sajid

    Solar energy is the cleanest, renewable and most abundant source of energy available on earth. The main use of solar energy is to heat and cool buildings, heat water and to generate electricity. There are two types of solar energy collection system, the photovoltaic systems and the solar thermal collectors. The efficiency of any solar thermal system depend on the thermophysical properties of the operating fluids and the geometry/length of the system in which fluid is flowing. In the present research a simplified mathematical model for the solar thermal collectors is considered in the form of non-uniform unsteady stretching surface. The flow is induced by a non-uniform stretching of the porous sheet and the uniform magnetic field is applied in the transverse direction to the flow. The non-Newtonian Maxwell fluid model is utilized for the working fluid along with slip boundary conditions. Moreover the high temperature effect of thermal radiation and temperature dependent thermal conductivity are also included in the present model. The mathematical formulation is carried out through a boundary layer approach and the numerical computations are carried out for cu-water and TiO2 -water nanofluids. Results are presented for the velocity and temperature profiles as well as the skin friction coefficient and Nusselt number and the discussion is concluded on the effect of various governing parameters on the motion, temperature variation, velocity gradient and the rate of heat transfer at the boundary.

  19. Solar thermal power systems. Program summary

    Energy Technology Data Exchange (ETDEWEB)

    1978-12-01

    Each of DOE's solar Thermal Power Systems projects funded and/or in existence during FY 1978 is described and the status as of September 30, 1978 is reflected. These projects are divided as follows: small thermal power applications, large thermal power applications, and advanced thermal technology. Also included are: 1978 project summary tables, bibliography, and an alphabetical index of contractors. (MHR)

  20. Ultrafast Thermal Cycling of Solar Panels

    National Research Council Canada - National Science Library

    Wall, T

    1998-01-01

    Two new cyclers that utilize a novel hybrid approach to perform fast thermal cycling of solar panels have been built and are now operational in the Mechanics and Materials Technology Center at The Aerospace Corporation...

  1. Concentrated Solar Power Gas Turbine Hybrid with Thermal Storage

    OpenAIRE

    Wallentinsen, Bård Sve

    2016-01-01

    Concentrated Solar Power (CSP) technology and shows promise for large-scale renewable electric power generation. CSP is suitable for development in conjunction with other technologies, and this thesis examines the combination of CSP technology with natural gas turbines in order to boost operating temperatures and efficiencies in a resulting solar hybrid gas turbine (SHGT) power plant. Thermal energy storage and a bottoming cycle are included in the design to increase both performance and rene...

  2. Validation of TRNSYS model for solar thermal facility; Validacion de un modelo TRNSYS para una instalacion solar termica

    Energy Technology Data Exchange (ETDEWEB)

    Lopez, G.; Macias, F. J.

    2004-07-01

    TRNSYS is a well-known tool to simulate solar systems. This paper is a summary of the validation process of a solar system TRNSYS model. An actual solar system, is modeled with standard TRNSYS components, the actual system is monitorized and the measures of consume, solar radiation, ambient temperature are used as inputs values for the TRNSYS model in order to compare the outputs of the simulations with the real values of the solar thermal installation. (Author)

  3. Solar thermal power systems. Summary report

    Energy Technology Data Exchange (ETDEWEB)

    1980-06-01

    The work accomplished by the Aerospace Corporation from April 1973 through November 1979 in the mission analysis of solar thermal power systems is summarized. Sponsorship of this effort was initiated by the National Science Foundation, continued by the Energy Research and Development Administration, and most recently directed by the United States Department of Energy, Division of Solar Thermal Systems. Major findings and conclusions are sumarized for large power systems, small power systems, solar total energy systems, and solar irrigation systems, as well as special studies in the areas of energy storage, industrial process heat, and solar fuels and chemicals. The various data bases and computer programs utilized in these studies are described, and tables are provided listing financial and solar cost assumptions for each study. An extensive bibliography is included to facilitate review of specific study results and methodology.

  4. PV/thermal solar power assembly

    Science.gov (United States)

    Ansley, Jeffrey H.; Botkin, Jonathan D.; Dinwoodie, Thomas L.

    2004-01-13

    A flexible solar power assembly (2) includes a flexible photovoltaic device (16) attached to a flexible thermal solar collector (4). The solar power assembly can be rolled up for transport and then unrolled for installation on a surface, such as the roof (20, 25) or side wall of a building or other structure, by use of adhesive and/or other types of fasteners (23).

  5. Comparison of selective transmitters for solar thermal applications.

    Science.gov (United States)

    Taylor, Robert A; Hewakuruppu, Yasitha; DeJarnette, Drew; Otanicar, Todd P

    2016-05-10

    Solar thermal collectors are radiative heat exchangers. Their efficacy is dictated predominantly by their absorption of short wavelength solar radiation and, importantly, by their emission of long wavelength thermal radiation. In conventional collector designs, the receiver is coated with a selectively absorbing surface (Black Chrome, TiNOx, etc.), which serves both of these aims. As the leading commercial absorber, TiNOx consists of several thin, vapor deposited layers (of metals and ceramics) on a metal substrate. In this technology, the solar absorption to thermal emission ratio can exceed 20. If a solar system requires an analogous transparent component-one which transmits the full AM1.5 solar spectrum, but reflects long wavelength thermal emission-the technology is much less developed. Bespoke "heat mirrors" are available from optics suppliers at high cost, but the closest mass-produced commercial technology is low-e glass. Low-e glasses are designed for visible light transmission and, as such, they reflect up to 50% of available solar energy. To address this technical gap, this study investigated selected combinations of thin films that could be deposited to serve as transparent, selective solar covers. A comparative numerical analysis of feasible materials and configurations was investigated using a nondimensional metric termed the efficiency factor for selectivity (EFS). This metric is dependent on the operation temperature and solar concentration ratio of the system, so our analysis covered the practical range for these parameters. It was found that thin films of indium tin oxide (ITO) and ZnS-Ag-ZnS provided the highest EFS. Of these, ITO represents the more commercially viable solution for large-scale development. Based on these optimized designs, proof-of-concept ITO depositions were fabricated and compared to commercial depositions. Overall, this study presents a systematic guide for creating a new class of selective, transparent optics for solar

  6. Temperature distribution and thermal stress

    Indian Academy of Sciences (India)

    The minimum stress and minimum stress difference are shown in equal double pumping. 4. Conclusion. In the present work, the temperature distribution and thermal stress of the actual double-end-pumped Nd:YVO4 cubic crystal have been discussed. The results show that by considering the input power as a constant, the ...

  7. Solar thermal repowering systems integration. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Dubberly, L. J.; Gormely, J. E.; McKenzie, A. W.

    1979-08-01

    This report is a solar repowering integration analysis which defines the balance-of-plant characteristics and costs associated with the solar thermal repowering of existing gas/oil-fired electric generating plants. Solar repowering interface requirements for water/steam and salt or sodium-cooled central receivers are defined for unit sizes ranging from 50 MWe non-reheat to 350 MWe reheat. Finally balance-of-plant cost estimates are presented for each of six combinations of plant type, receiver type and percent solar repowering.

  8. Solar cell junction temperature measurement of PV module

    KAUST Repository

    Huang, B.J.

    2011-02-01

    The present study develops a simple non-destructive method to measure the solar cell junction temperature of PV module. The PV module was put in the environmental chamber with precise temperature control to keep the solar PV module as well as the cell junction in thermal equilibrium with the chamber. The open-circuit voltage of PV module Voc is then measured using a short pulse of solar irradiation provided by a solar simulator. Repeating the measurements at different environment temperature (40-80°C) and solar irradiation S (200-1000W/m2), the correlation between the open-circuit voltage Voc, the junction temperature Tj, and solar irradiation S is derived.The fundamental correlation of the PV module is utilized for on-site monitoring of solar cell junction temperature using the measured Voc and S at a short time instant with open circuit. The junction temperature Tj is then determined using the measured S and Voc through the fundamental correlation. The outdoor test results show that the junction temperature measured using the present method, Tjo, is more accurate. The maximum error using the average surface temperature Tave as the junction temperature is 4.8 °C underestimation; while the maximum error using the present method is 1.3 °C underestimation. © 2010 Elsevier Ltd.

  9. Thermally-Induced Structural Disturbances of Rigid Panel Solar Arrays

    Science.gov (United States)

    Johnston, John D.; Thornton, Earl A.

    1997-01-01

    The performance of a significant number of spacecraft has been impacted negatively by attitude disturbances resulting from thermally-induced motions of flexible structures. Recent examples of spacecraft affected by these disturbances include the Hubble Space Telescope (HST) and the Upper Atmosphere Research Satellite (UARS). Thermally-induced structural disturbances occur as the result of rapid changes in thermal loading typically initiated as a satellite exits or enters the Earth's shadow. Temperature differences in flexible appendages give rise to structural deformations, which in turn result in disturbance torques reacting back on the spacecraft. Structures which have proven susceptible to these disturbances include deployable booms and solar arrays. This paper investigates disturbances resulting from thermally-induced deformations of rigid panel solar arrays. An analytical model for the thermal-structural response of the solar array and the corresponding disturbance torque are presented. The effect of these disturbances on the attitude dynamics of a simple spacecraft is then investigated using a coupled system of governing equations which includes the effects of thermally-induced deformations. Numerical results demonstrate the effect of varying solar array geometry on the dynamic response of the system.

  10. Hybrids of Solar Sail, Solar Electric, and Solar Thermal Propulsion for Solar-System Exploration

    Science.gov (United States)

    Wilcox, Brian H.

    2012-01-01

    Solar sails have long been known to be an attractive method of propulsion in the inner solar system if the areal density of the overall spacecraft (S/C) could be reduced to approx.10 g/sq m. It has also long been recognized that the figure (precise shape) of useful solar sails needs to be reasonably good, so that the reflected light goes mostly in the desired direction. If one could make large reflective surfaces with reasonable figure at an areal density of approx.10 g/sq m, then several other attractive options emerge. One is to use such sails as solar concentrators for solar-electric propulsion. Current flight solar arrays have a specific output of approx. 100W/kg at 1 Astronomical Unit (AU) from the sun, and near-term advances promise to significantly increase this figure. A S/C with an areal density of 10 g/sq m could accelerate up to 29 km/s per year as a solar sail at 1 AU. Using the same sail as a concentrator at 30 AU, the same spacecraft could have up to approx. 45 W of electric power per kg of total S/C mass available for electric propulsion (EP). With an EP system that is 50% power-efficient, exhausting 10% of the initial S/C mass per year as propellant, the exhaust velocity is approx. 119 km/s and the acceleration is approx. 12 km/s per year. This hybrid thus opens attractive options for missions to the outer solar system, including sample-return missions. If solar-thermal propulsion were perfected, it would offer an attractive intermediate between solar sailing in the inner solar system and solar electric propulsion for the outer solar system. In the example above, both the solar sail and solar electric systems don't have a specific impulse that is near-optimal for the mission. Solar thermal propulsion, with an exhaust velocity of the order of 10 km/s, is better matched to many solar system exploration missions. This paper derives the basic relationships between these three propulsion options and gives examples of missions that might be enabled by

  11. Solar thermal electric power information user study

    Energy Technology Data Exchange (ETDEWEB)

    Belew, W.W.; Wood, B.L.; Marle, T.L.; Reinhardt, C.L.

    1981-02-01

    The results of a series of telephone interviews with groups of users of information on solar thermal electric power are described. These results, part of a larger study on many different solar technologies, identify types of information each group needed and the best ways to get information to each group. The report is 1 of 10 discussing study results. The overall study provides baseline data about information needs in the solar community. An earlier study identified the information user groups in the solar community and the priority (to accelerate solar energy commercialization) of getting information to each group. In the current study only high-priority groups were examined. Results from five solar thermal electric power groups of respondents are analyzed: DOE-Funded Researchers, Non-DOE-Funded Researchers, Representatives of Utilities, Electric Power Engineers, and Educators. The data will be used as input to the determination of information products and services the Solar Energy Research Institute, the Solar Energy Information Data Bank Network, and the entire information outreach community should be preparing and disseminating.

  12. Metal hydrides for concentrating solar thermal power energy storage

    Science.gov (United States)

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

    2016-04-01

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

  13. Solar-Tep. Solar thermal power. Final report; Solar-Tep. Solare Thermokraft. Final Report

    Energy Technology Data Exchange (ETDEWEB)

    Robert, R.; Weidenkaff, A.

    2006-07-01

    The direct and efficient conversion of concentrated solar radiation into electricity with a high power output requires the development of thermoelectrically active p- and n-type semiconductors with similar material properties which are stable in air at very high temperature. The only suitable materials that fulfil this task are high performance ceramics. We successfully developed and investigated novel perovskite-type transition-metal oxides as potential candidates for thermoelectric devices operating at high temperatures as they can possess large positive as well as large negative thermo-power depending on their composition. The three parameters defining the thermoelectric figure of merit ZT are in most cases interdependent: the thermo-power increases with increasing resistivity. The heat conductivity increases with electrical conductivity. Therefore, an optimum charge carrier concentration and mobility has to be defined, which depends on the substitution level, the spin states of the transition metals, the Ligand field, i.e. the crystallographic structure, the valence states of the cations and ionic deficiencies. The tuning of the thermoelectric properties of the perovskite-type candidates is based on controlled anionic and cationic substitutions. The resulting products are characterised as far as structure and composition are concerned using various methods available at EMPA and at large scale facilities including Xray and Neutron Diffraction, transmission electron microscopy, thermal analysis, synchrotron-radiation-based techniques (EXAFS, XANES, Diffraction) as well as Raman spectroscopy and tested concerning their thermoelectric activity in the new thermoelectricity lab at EMPA. (author)

  14. Thin Thermal-Insulation Blankets for Very High Temperatures

    Science.gov (United States)

    Choi, Michael K.

    2003-01-01

    Thermal-insulation blankets of a proposed type would be exceptionally thin and would endure temperatures up to 2,100 C. These blankets were originally intended to protect components of the NASA Solar Probe spacecraft against radiant heating at its planned closest approach to the Sun (a distance of 4 solar radii). These blankets could also be used on Earth to provide thermal protection in special applications (especially in vacuum chambers) for which conventional thermal-insulation blankets would be too thick or would not perform adequately.

  15. Improved high temperature solar absorbers for use in Concentrating Solar Power central receiver applications.

    Energy Technology Data Exchange (ETDEWEB)

    Stechel, Ellen Beth; Ambrosini, Andrea; Hall, Aaron Christopher; Lambert, Timothy L.; Staiger, Chad Lynn; Bencomo, Marlene

    2010-09-01

    Concentrating solar power (CSP) systems use solar absorbers to convert the heat from sunlight to electric power. Increased operating temperatures are necessary to lower the cost of solar-generated electricity by improving efficiencies and reducing thermal energy storage costs. Durable new materials are needed to cope with operating temperatures >600 C. The current coating technology (Pyromark High Temperature paint) has a solar absorptance in excess of 0.95 but a thermal emittance greater than 0.8, which results in large thermal losses at high temperatures. In addition, because solar receivers operate in air, these coatings have long term stability issues that add to the operating costs of CSP facilities. Ideal absorbers must have high solar absorptance (>0.95) and low thermal emittance (<0.05) in the IR region, be stable in air, and be low-cost and readily manufacturable. We propose to utilize solution-based synthesis techniques to prepare intrinsic absorbers for use in central receiver applications.

  16. The Effects of Solar Irradience and Ambient Temperature on Solar ...

    African Journals Online (AJOL)

    Optimizing this conversion, especially in the face of the high cost of solar panels, is thus desirable. Towards this end, it is necessary to know the maximum output periods of solar modules and the conditions for maximum panel output. This paper is the result of a study of the effects of solar irradiance and ambient temperature ...

  17. Mathematical Modeling and Numerical Analysis of Thermal Distribution in Arch Dams considering Solar Radiation Effect

    Science.gov (United States)

    Mirzabozorg, H.; Hariri-Ardebili, M. A.; Shirkhan, M.; Seyed-Kolbadi, S. M.

    2014-01-01

    The effect of solar radiation on thermal distribution in thin high arch dams is investigated. The differential equation governing thermal behavior of mass concrete in three-dimensional space is solved applying appropriate boundary conditions. Solar radiation is implemented considering the dam face direction relative to the sun, the slop relative to horizon, the region cloud cover, and the surrounding topography. It has been observed that solar radiation changes the surface temperature drastically and leads to nonuniform temperature distribution. Solar radiation effects should be considered in thermal transient analysis of thin arch dams. PMID:24695817

  18. Thermal Advantages for Solar Heating Systems with a Glass Cover with Antireflection Surfaces

    DEFF Research Database (Denmark)

    Furbo, Simon; Shah, Louise Jivan

    2003-01-01

    Investigations elucidate how a glass cover with antireflection surfaces can improve the efficiency of a solar collector and the thermal performance of solar heating systems. The transmittances for two glass covers for a flat-plate solar collector were measured for different incidence angles...... was determined for different solar heating systems. Three systems were investigated: solar domestic hot water systems, solar heating systems for combined space heating demand and domestic hot water supply, and large solar heating plants. The yearly thermal performance of the systems was calculated by detailed...... simulation models with collectors with a normal glass cover and with a glass cover with antireflection surfaces. The calculations were carried out for different solar fractions and temperature levels of the solar heating systems. These parameters influence greatly the thermal performance associated...

  19. Simple Continuous-Flow Device for Combined Solar Thermal Pasteurization and Solar Disinfection for Water Sterilization

    Directory of Open Access Journals (Sweden)

    Anthony Amsberry

    2015-02-01

    Full Text Available A collection unit and reflective concentrators were used to thermally preheat water to at least 70 °C for thermal pasteurization prior to a solar disinfection stage. The device is offered as a novel combined cycle to be used for either solar thermal pasteurization, during seasonalpeaks in solar irradiation, or as a solar preheat for UV solar disinfection which would occur in a flow-through solar disinfection trough. Inexpensive materials were used in order to simulate in field functionality and applicability to rural regions with low solar input. Solar incidence at Oregon State University, with latitude 45.5°, was recorded during trials conducted during May 1 to June 10 for the purpose of directly scaling the water treatment volumetric flowrate of the device for any future tests in other locations. This scaling by solar irradiation makes this dataset useful for other locations with higher or lower solar input and needing more or less treated water. The simple gravity-fed continuous system presented in this article makes use of a large cold water reservoir, a shell-and-tube heat exchanger, and a solar collector. The system, operating at flowrates of 100-150 mL/min is able to reach outlet temperatures of 74°C.  The system is projected to produce 55 L of purified water daily when operating on a sunny day with peak UV radiation above 700 W/m2. System cost was $55 with an added optional $15 for the shell-and-tube heat exchanger.

  20. Thermal advantage of tracking solar collectors under Danish weather conditions

    DEFF Research Database (Denmark)

    Andersen, Elsa; Dragsted, Janne; Furbo, Simon

    2010-01-01

    Theoretical investigations have been carried out with the aim to elucidate the thermal advantage of tracking solar collectors for different weather conditions in Kgs. Lyngby, Denmark (55.8°N), and for the weather conditions in Sisimiut, Greenland (66.9°N), just north of the arctic circle....... The investigations are based on calculations with a newly developed program. Measured weather data from a solar radiation measurement station at Technical University of Denmark in Kgs. Lyngby Denmark in the period 1990 to 2002 and the Danish Design Reference Year, DRY data file are used in the investigations....... The weather data used for Sisimiut are based on a Test Reference Year, TRY weather data file. The thermal advantages of different tracking strategies is investigated for two flat plate solar collectors with different efficiencies, operated at different temperature levels. The investigations show...

  1. Solar thermal plant impact analysis and requirements definition study

    Science.gov (United States)

    1982-01-01

    The technology and economics of solar thermal electric systems (STES) for electric power production is discussed. The impacts of and requirements for solar thermal electric power systems were evaluated.

  2. Solar thermal harvesting for enhanced photocatalytic reactions.

    Science.gov (United States)

    Hashemi, Seyyed Mohammad Hosseini; Choi, Jae-Woo; Psaltis, Demetri

    2014-03-21

    The Shockley-Queisser limit predicts a maximum efficiency of 30% for single junction photovoltaic (PV) cells. The rest of the solar energy is lost as heat and due to phenomena such as reflection and transmission through the PV and charge carrier recombination. In the case of photocatalysis, this maximum value is smaller since the charge carriers should be transferred to acceptor molecules rather than conductive electrodes. With this perspective, we realize that at least 70% of the solar energy is available to be converted into heat. This is specifically useful for photocatalysis, since heat can provide more kinetic energy to the reactants and increase the number of energetic collisions leading to the breakage of chemical bonds. Even in natural photosynthesis, at the most 6% of the solar spectrum is used to produce sugar and the rest of the absorbed photons are converted into heat in a process called transpiration. The role of this heating component is often overlooked; in this paper, we demonstrate a coupled system of solar thermal and photocatalytic decontamination of water by titania, the most widely used photocatalyst for various photo reactions. The enhancement of this photothermal process over solely photocatalytic water decontamination is demonstrated to be 82% at 1× sun. Our findings suggest that the combination of solar thermal energy capture with photocatalysis is a suitable strategy to utilize more of the solar spectrum and improve the overall performance.

  3. Buffer thermal energy storage for an air Brayton solar engine

    Science.gov (United States)

    Strumpf, H. J.; Barr, K. P.

    1981-01-01

    The application of latent-heat buffer thermal energy storage to a point-focusing solar receiver equipped with an air Brayton engine was studied. To demonstrate the effect of buffer thermal energy storage on engine operation, a computer program was written which models the recuperator, receiver, and thermal storage device as finite-element thermal masses. Actual operating or predicted performance data are used for all components, including the rotating equipment. Based on insolation input and a specified control scheme, the program predicts the Brayton engine operation, including flows, temperatures, and pressures for the various components, along with the engine output power. An economic parametric study indicates that the economic viability of buffer thermal energy storage is largely a function of the achievable engine life.

  4. Non-uniform Solar Temperature Field on Large Aperture, Fully ...

    Indian Academy of Sciences (India)

    In this study, a 110-m fully steerable radio telescope was used as an analysis platform and the integral parametric finite element model of the antenna structure was built in the ANSYS thermal analysis module. The boundary conditions of periodic air temperature, solar radiation, long-wave radiation shadows of the ...

  5. Thermal design of spacecraft solar arrays using a polyimide foam

    Science.gov (United States)

    Bianco, N.; Iasiello, M.; Naso, V.

    2015-11-01

    The design of the Thermal Control System (TCS) of spacecraft solar arrays plays a fundamental role. Indeed, the spacecraft components must operate within a certain range of temperature. If this doesn't occur, their performance is reduced and they may even break. Solar arrays, which are employed to recharge batteries, are directly exposed to the solar heat flux, and they need to be insulated from the earth's surface irradiation. Insulation is currently provided either with a white paint coating or with a Multi Layer Insulation (MLI) system [1]. A configuration based on an open-cell polyimide foam has also been recently proposed [2]. Using polyimide foams in TCSs looks very attractive in terms of costs, weight and assembling. An innovative thermal analysis of the above cited TCS configurations is carried out in this paper, by solving the porous media energy equation, under the assumption of Local Thermal Equilibrium (LTE) between the two phases. Radiation effects through the solar array are also considered by using the Rosseland approximation. Under a stationary daylight condition, temperature profiles are obtained by means of the finite-element based code COMSOL Multiphysics®. Finally, since the weight plays an important role in aerospace applications, weights of the three TCS configurations are compared.

  6. Flexible thermal cycle test equipment for concentrator solar cells

    Science.gov (United States)

    Hebert, Peter H [Glendale, CA; Brandt, Randolph J [Palmdale, CA

    2012-06-19

    A system and method for performing thermal stress testing of photovoltaic solar cells is presented. The system and method allows rapid testing of photovoltaic solar cells under controllable thermal conditions. The system and method presents a means of rapidly applying thermal stresses to one or more photovoltaic solar cells in a consistent and repeatable manner.

  7. Thermal properties of carbon black aqueous nanofluids for solar absorption

    Directory of Open Access Journals (Sweden)

    Han Dongxiao

    2011-01-01

    Full Text Available Abstract In this article, carbon black nanofluids were prepared by dispersing the pretreated carbon black powder into distilled water. The size and morphology of the nanoparticles were explored. The photothermal properties, optical properties, rheological behaviors, and thermal conductivities of the nanofluids were also investigated. The results showed that the nanofluids of high-volume fraction had better photothermal properties. Both carbon black powder and nanofluids had good absorption in the whole wavelength ranging from 200 to 2,500 nm. The nanofluids exhibited a shear thinning behavior. The shear viscosity increased with the increasing volume fraction and decreased with the increasing temperature at the same shear rate. The thermal conductivity of carbon black nanofluids increased with the increase of volume fraction and temperature. Carbon black nanofluids had good absorption ability of solar energy and can effectively enhance the solar absorption efficiency.

  8. Temperature mapping, thermal diffusivity and subsoil heat flux at ...

    Indian Academy of Sciences (India)

    R. Narasimhan (Krishtel eMaging) 1461 1996 Oct 15 13:05:22

    the day by intense solar radiation than the lay- ers beneath, resulting in temperature gradient between the surface and subsoil on the one hand and surface and air layers near the ground on the other. Within the soil this causes heat flow downward as a thermal wave, the amplitude of which changes with depth. Estimation of ...

  9. Solar Probe Plus MAG Sensor Thermal Design for Low Heater Power and Extreme Thermal Environment

    Science.gov (United States)

    Choi, Michael K.

    2015-01-01

    The heater power available for the Solar Probe Plus FIELDS MAG sensor is less than half of the heritage value for other missions. Nominally the MAG sensors are in the spacecraft's umbra. In the worst hot case, approximately 200 spacecraft communication downlinks, up to 10 hours each, are required at 0.7 AU. These downlinks require the spacecraft to slew 45 deg. about the Y-axis, exposing the MAG sensors and boom to sunlight. This paper presents the thermal design to meet the MAG sensor thermal requirements in the extreme thermal environment and with low heater power. A thermal balance test on the MAG sensor engineering model has verified the thermal design and correlated the thermal model for flight temperature predictions.

  10. Novel Thermal Storage Technologies for Concentrating Solar Power Generation

    Energy Technology Data Exchange (ETDEWEB)

    Neti, Sudhakar [Lehigh Univ., Bethlehem, PA (United States). Mechanical Engineering and Mechanics; Oztekin, Alparslan [Lehigh Univ., Bethlehem, PA (United States); Chen, John [Lehigh Univ., Bethlehem, PA (United States); Tuzla, Kemal [Lehigh Univ., Bethlehem, PA (United States); Misiolek, Wojciech [Lehigh Univ., Bethlehem, PA (United States)

    2013-06-20

    The technologies that are to be developed in this work will enable storage of thermal energy in 100 MWe solar energy plants for 6-24 hours at temperatures around 300°C and 850°C using encapsulated phase change materials (EPCM). Several encapsulated phase change materials have been identified, fabricated and proven with calorimetry. Two of these materials have been tested in an airflow experiment. A cost analysis for these thermal energy storage systems has also been conducted that met the targets established at the initiation of the project.

  11. Full-spectrum volumetric solar thermal conversion via photonic nanofluids.

    Science.gov (United States)

    Liu, Xianglei; Xuan, Yimin

    2017-10-12

    Volumetric solar thermal conversion is an emerging technique for a plethora of applications such as solar thermal power generation, desalination, and solar water splitting. However, achieving broadband solar thermal absorption via dilute nanofluids is still a daunting challenge. In this work, full-spectrum volumetric solar thermal conversion is demonstrated over a thin layer of the proposed 'photonic nanofluids'. The underlying mechanism is found to be the photonic superposition of core resonances, shell plasmons, and core-shell resonances at different wavelengths, whose coexistence is enabled by the broken symmetry of specially designed composite nanoparticles, i.e., Janus nanoparticles. The solar thermal conversion efficiency can be improved by 10.8% compared with core-shell nanofluids. The extinction coefficient of Janus dimers with various configurations is also investigated to unveil the effects of particle couplings. This work provides the possibility to achieve full-spectrum volumetric solar thermal conversion, and may have potential applications in efficient solar energy harvesting and utilization.

  12. Preliminary Low Temperature Electron Irradiation of Triple Junction Solar Cells

    Science.gov (United States)

    Stella, Paul M.; Mueller, Robert L.; Scrivner, Roy L.; Helizon, Roger S.

    2007-01-01

    For many years extending solar power missions far from the sun has been a challenge not only due to the rapid falloff in solar intensity (intensity varies as inverse square of solar distance) but also because some of the solar cells in an array may exhibit a LILT (low intensity low temperature) degradation that reduces array performance. Recent LILT tests performed on commercial triple junction solar cells have shown that high performance can be obtained at solar distances as great as approx. 5 AU1. As a result, their use for missions going far from the sun has become very attractive. One additional question that remains is whether the radiation damage experienced by solar cells under low temperature conditions will be more severe than when measured during room temperature radiation tests where thermal annealing may take place. This is especially pertinent to missions such as the New Frontiers mission Juno, which will experience cell irradiation from the trapped electron environment at Jupiter. Recent testing2 has shown that low temperature proton irradiation (10 MeV) produces cell degradation results similar to room temperature irradiations and that thermal annealing does not play a factor. Although it is suggestive to propose the same would be observed for low temperature electron irradiations, this has not been verified. JPL has routinely performed radiation testing on commercial solar cells and has also performed LILT testing to characterize cell performance under far sun operating conditions. This research activity was intended to combine the features of both capabilities to investigate the possibility of any room temperature annealing that might influence the measured radiation damage. Although it was not possible to maintain the test cells at a constant low temperature between irradiation and electrical measurements, it was possible to obtain measurements with the cell temperature kept well below room temperature. A fluence of 1E15 1MeV electrons was

  13. Renewable Energy Essentials: Concentrating Solar Thermal Power

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2009-07-01

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

  14. Solar Thermal Propulsion for Microsatellite Manoeuvring

    Science.gov (United States)

    2004-09-01

    kg), acetylene (614 kJ/kg), and xenon (96.3 kJ/kg) [Lide, 1995][ Air Liquide , 2004]. Solar Thermal Propulsion for Microsatellite Manoeuvring 197...Archives, Kirtland Air Force Base, New Mexico, 2004 [accessed 6 May 2004]. [ Air Liquide , 2004] http://www.airliquide.com/en/business/products/gases...gasdata/index.asp, “Gases,” Air Liquide , Paris, France, March 2004 [accessed 26 March 2004]. [Amass, 2000] http://www.lanternroom.com/misc

  15. Performance of solar collectors under low temperature conditions

    DEFF Research Database (Denmark)

    Bunea, Mircea; Eicher, Sara; Hildbrand, Catherine

    evaluated and results compared to experimental measurements. A mathematical model is also under development to include, in addition to the condensation phenomena, the frost, the rain and the long-wave radiation gains/losses on the rear of the solar collector. While the potential gain from rain was estimated......The performance of four solar thermal collectors (flat plate, evacuated tube, unglazed with rear insulation and unglazed without rear insulation) was experimentally measured and simulated for temperatures below ambient. The influence of several parameters (e.g. collector inlet temperature, air...

  16. A performance analysis of solar chimney thermal power systems

    Directory of Open Access Journals (Sweden)

    Al-Dabbas Awwad Mohammed

    2011-01-01

    Full Text Available The objective of this study was to evaluate the solar chimney performance theoretically (techno-economic. A mathematical model was developed to estimate the following parameter: Power output, Pressure drop across the turbine, the max chimney height, Airflow temperature, and the overall efficiency of solar chimney. The mathematical model was validated with experimental data from the prototype in Manzanares power. It can be concluded that the differential pressure of collector-chimney transition section in the system, is increase with the increase of solar radiation intensity. The specific system costs are between 2000 Eur/kW and 5000 Eur/kW depending on the system size, system concept and storage size. Hence, a 50 MWe solar thermal power plant will cost 100-250 Eur million. At very good sites, today’s solar thermal power plants can generate electricity in the range of 0.15 Eur/kWh, and series production could soon bring down these costs below 0.10 Eur /kWh.

  17. Rapid thermal sintering of the metallizations of silicon solar cells

    Energy Technology Data Exchange (ETDEWEB)

    Laugier, A.; El Omari, H.; Boyeaux, J.P. [Institut National des Sciences Appliquees de Lyon, Villeurbanne (France). Lab. de Physique de la Matiere; Hartiti, B.; Muller, J.C. [CNRS, Strasbourg (France). Lab. de Physique et Applications des Semiconducteurs; Nam, L.Q.; Sarti, D. [Photowatt International S.A., Bourgoin Jallieu (France)

    1994-12-31

    Rapid Thermal Processing (RTP) using radiation from tungsten halogen lamps as a heat source is a very promising candidate to replace conventional furnace annealing as it offers many advantages such as a reduced overall thermal budget and a lower gas consumption. In this paper the authors show that with moderate temperature, RTP can be used to obtain screen printed contacts with low contacts resistivity and without degrading the transport properties of the solar cell base region. They investigate on Polix multicrystalline solar cells the possibility to replace the conventional sintering by a RTP annealing of the Ag front grid and of the back Al/Ag contact in a single step performed after the antireflection coating deposition.

  18. Thermal Cycling of Mir Cooperative Solar Array (MCSA) Test Panels

    Science.gov (United States)

    Hoffman, David J.; Scheiman, David A.

    1997-01-01

    The Mir Cooperative Solar Array (MCSA) project was a joint US/Russian effort to build a photovoltaic (PV) solar array and deliver it to the Russian space station Mir. The MCSA is currently being used to increase the electrical power on Mir and provide PV array performance data in support of Phase 1 of the International Space Station (ISS), which will use arrays based on the same solar cells used in the MCSA. The US supplied the photovoltaic power modules (PPMs) and provided technical and programmatic oversight while Russia provided the array support structures and deployment mechanism and built and tested the array. In order to ensure that there would be no problems with the interface between US and Russian hardware, an accelerated thermal life cycle test was performed at NASA Lewis Research Center on two representative samples of the MCSA. Over an eight-month period (August 1994 - March 1995), two 15-cell MCSA solar array 'mini' panel test articles were simultaneously put through 24,000 thermal cycles (+80 C to -100 C), equivalent to four years on-orbit. The test objectives, facility, procedure and results are described in this paper. Post-test inspection and evaluation revealed no significant degradation in the structural integrity of the test articles and no electrical degradation, not including one cell damaged early as an artifact of the test and removed from consideration. The interesting nature of the performance degradation caused by this one cell, which only occurred at elevated temperatures, is discussed. As a result of this test, changes were made to improve some aspects of the solar cell coupon-to-support frame interface on the flight unit. It was concluded from the results that the integration of the US solar cell modules with the Russian support structure would be able to withstand at least 24,000 thermal cycles (4 years on-orbit).

  19. Synergies with renewables: Concentrating solar thermal

    Energy Technology Data Exchange (ETDEWEB)

    Louis Wibberley; Aaron Cottrell; Peter Scaife; Phil Brown

    2006-10-15

    This report summarises the status of concentrating solar thermal technology (CST) for the generating of electricity, the synergies and integration with fossil fuel-based generation, and for reforming of natural gas. The report covers information up to September 2005. Overall CST technology has lagged in development and application in comparison with other renewable technologies, such as wind and photovoltaics, but it has been predicted that if the higher rate of commercial application is achieved, the technology will play a significant role in base-load generation for Australia and other countries which have high levels of direct solar insolation. In Australia, the large quantities of natural gas, and coal seam gas and the well developed gas and electricity grids, coupled with large areas with high solar insolation, provide an opportunity for using this approach to make a significant reduction in greenhouse emissions per unit of electricity, and in the amount of fossil energy consumption. CSIRO has a major research program in this area. Of the technologies, parabolic troughs are under the most active development, with the Andasol plant in Spain being the most recent example and with several novel features. The compact linear Fresnel reflector (CLFR) technology being applied at Liddell power station in New South Wales is also an interesting approach, and the recently announced expansion of collector area, and integration into the steam cycle will provide important engineering and operating information. The interaction with coal based electricity generation can be through direct input of solar thermal energy into the steam cycle (as at coal-fired Liddell power station) or through use of the thermal energy to, for example, regenerate sorbents in a post combustion CO{sub 2} capture plant associated with a power station. This latter approach reduces the parasitic power losses from the power station. 36 refs., 37 figs., 11 tabs.

  20. Design and Development of a Solar Thermal Collector with Single Axis Solar Tracking Mechanism

    Directory of Open Access Journals (Sweden)

    Theebhan Mogana

    2016-01-01

    Full Text Available The solar energy is a source of energy that is abundant in Malaysia and can be easily harvested. However, because of the rotation of the Earth about its axis, it is impossible to harvest the solar energy to the maximum capacity if the solar thermal collector is placed fix to a certain angle. In this research, a solar thermal dish with single axis solar tracking mechanism that will rotate the dish according to the position of the sun in the sky is designed and developed, so that more solar rays can be reflected to a focal point and solar thermal energy can be harvested from the focal point. Data were collected for different weather conditions and performance of the solar thermal collector with a solar tracker were studied and compared with stationary solar thermal collector.

  1. Solar thermal energy utilization in Brazil: a perspective; Utilizacao da energia solar termica no Brasil: uma perspectiva

    Energy Technology Data Exchange (ETDEWEB)

    Miller, Francisco Mateus [PETROBRAS, Rio de Janeiro, RJ (Brazil)

    2004-07-01

    Although Brazil has a large insolation potential, utilization of solar thermal energy is still limited to few applications, like residential and commercial water heating and drying of grains. However, there are in other countries more intensive applications, like electricity generation, industrial heat and fresh water production. The present work describes which are the other ways of using solar thermal energy that have been developed in the world, approaches the main technical aspects that affect its utilization, the perspective of increasing it in Brazil and its possible barriers and, finally, PETROBRAS' studies in this area, positioning itself as an Energy Company. The main solar thermal technologies currently used in the world are evacuated collectors, that work efficiently at temperatures up to 130 deg C, and concentrating solar technologies, that can reach the temperature of 1200 deg C. Among the latter, solar trough is the technology that is already considered mature, and near to become economically viable. Brazil, at the moment, has two technological challenges: development of national technology to manufacture high performance solar collectors, like evacuated collectors and solar troughs, and the development of thermal equipment to operate at temperatures under 120 deg C, like adsorption and absorption chillers and desalination towers, that can be economically competitive. (author)

  2. Thermal Shield and Reactor Structure Temperatures

    Energy Technology Data Exchange (ETDEWEB)

    Collier, A.R.

    2001-07-31

    The purpose of this report is to present reactor structure and thermal shield temperature data taken during P-3 and P-5 cycles and compare them with design calculations in order to predict temperatures at higher power levels.

  3. Solar thermal heating and cooling. A bibliography with abstracts

    Science.gov (United States)

    Arenson, M.

    1979-01-01

    This bibliographic series cites and abstracts the literature and technical papers on the heating and cooling of buildings with solar thermal energy. Over 650 citations are arranged in the following categories: space heating and cooling systems; space heating and cooling models; building energy conservation; architectural considerations, thermal load computations; thermal load measurements, domestic hot water, solar and atmospheric radiation, swimming pools; and economics.

  4. Solar applications of thermal energy storage. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Lee, C.; Taylor, L.; DeVries, J.; Heibein, S.

    1979-01-01

    A technology assessment is presented on solar energy systems which use thermal energy storage. The study includes characterization of the current state-of-the-art of thermal energy storage, an assessment of the energy storage needs of solar energy systems, and the synthesis of this information into preliminary design criteria which would form the basis for detailed designs of thermal energy storage. (MHR)

  5. Experimental characterization of a solar cooker with thermal energy storage based on solar salt

    Science.gov (United States)

    Coccia, G.; Di Nicola, G.; Tomassetti, S.; Gabrielli, G.; Chieruzzi, M.; Pierantozzi, M.

    2017-11-01

    High temperature solar cooking allows to cook food fast and with good efficiency. An unavoidable drawback of this technology is that it requires nearly clear-sky conditions. In addition, evening cooking is difficult to be accomplished, particularly on the winter season during which solar radiation availability is limited to a few hours in the afternoon in most of countries. These restrictions could be overcome using a cooker thermal storage unit (TSU). In this work, a TSU based on solar salt was studied. The unit consists of two metal concentric cylindrical vessels, connected together to form a double-walled vessel. The volume between walls was filled with a certain amount of nitrate based phase change material (solar salt). In order to characterize the TSU, a test bench used to assess solar cooker performance was adopted. Experimental load tests with the TSU were carried out to evaluate the cooker performance. The obtained preliminary results show that the adoption of the solar salt TSU seems to allow both the opportunity of evening cooking and the possibility to better stabilize the cooker temperature when sky conditions are variable.

  6. Solar Thermal AIR Collector Based on New Type Selective Coating

    National Research Council Canada - National Science Library

    Musiy, R.Y; Midyana, G.G; Makitra, R.G; Vasyutin, J.M; Khovanets, G.I; Zaborowskiy, A.B

    2014-01-01

    Based on the best for optical performance and selective coating solar thermal air collector, which operates by solar power on the principle of simultaneous ventilation and heating facilities, is designed...

  7. Evaluation of solar thermal storage for base load electricity generation

    Directory of Open Access Journals (Sweden)

    Adinberg R.

    2012-10-01

    Full Text Available In order to stabilize solar electric power production during the day and prolong the daily operating cycle for several hours in the nighttime, solar thermal power plants have the options of using either or both solar thermal storage and fossil fuel hybridization. The share of solar energy in the annual electricity production capacity of hybrid solar-fossil power plants without energy storage is only about 20%. As it follows from the computer simulations performed for base load electricity demand, a solar annual capacity as high as 70% can be attained by use of a reasonably large thermal storage capacity of 22 full load operating hours. In this study, the overall power system performance is analyzed with emphasis on energy storage characteristics promoting a high level of sustainability for solar termal electricity production. The basic system parameters, including thermal storage capacity, solar collector size, and annual average daily discharge time, are presented and discussed.

  8. Analytical Methods for Temperature Field and Temperature Stress of Column Pier under Solar Radiation

    Directory of Open Access Journals (Sweden)

    Yin-hui Wang

    2015-01-01

    Full Text Available Based on the previous research work, a new idea is proposed for analyzing the impact of solar radiation on the substructure of bridges. Investigation is conducted in the thermodynamic phenomena and temperature stress of a dual-column pier. Research is led to the thermal conductivity of concrete structure and the values of the environmental parameters under solar radiation. An analytical code is written for the thermal analysis of the dual-column pier using the parametric modeling function of FE software, by means of which the temperature distribution of the bridge structure is computed under solar radiation. Using the thermal analytical results, the temperature stress of the dual-column pier is further calculated. The results tell that the temperature gradient distribution curve inside the concrete of the pier fits favorably the curve defined in the design specification and coincides quite well with real situation, which verifies the new idea proposed in this paper. Under the solar radiation which is a time-variable nonlinear temperature load to the bridge, the maximum principal stress is found at the corner of the pier with the sign of negative, which is believed to threaten the safety of the substructure of bridge and is necessary to arouse emphasis.

  9. Solar thermal energy. Solar pasteurization of dairy products; Energia solar termica. Pasteurizacion solar

    Energy Technology Data Exchange (ETDEWEB)

    Rosell, J.; Chemisana, D.

    2009-07-01

    Nicaragua is one of the south America countries with biggest cattle figures; however, it is at the bottom of the list of milk consumers. The cause which explains this is a twofold trouble. First of all, they have not the adequate milk treatment methods to guarantee a proper hygienic and conservation conditions. By the other side, production is distributed in small production centers to serve local consumers. this article proposal is to get a pasteurization treatment with thermal processes arranged by means of the solar energy. (Author) 3 refs.

  10. Active thermal isolation for temperature responsive sensors

    Science.gov (United States)

    Martinson, Scott D. (Inventor); Gray, David L. (Inventor); Carraway, Debra L. (Inventor); Reda, Daniel C. (Inventor)

    1994-01-01

    A temperature responsive sensor is located in the airflow over the specified surface of a body and is maintained at a constant temperature. An active thermal isolator is located between this temperature responsive sensor and the specified surface of the body. The temperature of this isolator is controlled to reduce conductive heat flow from the temperature responsive sensor to the body. This temperature control includes: (1) operating the isolator at the same temperature as the constant temperature of the sensor and (2) establishing a fixed boundary temperature which is either less than or equal to or slightly greater than the sensor constant temperature.

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

    Energy Technology Data Exchange (ETDEWEB)

    Segaser, C. L.

    1978-08-01

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

  12. Latest developments in the field of solar thermal standardisation

    OpenAIRE

    Fischer, S.; M. J. Carvalho; Kovacs, P.; Malenkovic, I.

    2011-01-01

    The European project QAiST-―Quality Assurance in Solar Thermal Heating and Cooling Technology‖ funded by the Intelligent Energy Europe program and by the participating countries, gathers 15 participating organizations including the European Solar Thermal Industry Federation ESTIF and major testing and research institutes in Europe. The objective of the project is to enhance the competitiveness of the European Solar thermal industry and further increase consumer confidence through improved ...

  13. Thermal analysis and design of passive solar buildings

    CERN Document Server

    Athienitis, AK

    2013-01-01

    Passive solar design techniques are becoming increasingly important in building design. This design reference book takes the building engineer or physicist step-by-step through the thermal analysis and design of passive solar buildings. In particular it emphasises two important topics: the maximum utilization of available solar energy and thermal storage, and the sizing of an appropriate auxiliary heating/cooling system in conjunction with good thermal control.Thermal Analysis and Design of Passive Solar Buildings is an important contribution towards the optimization of buildings as systems th

  14. Basic aspects for application of solar thermal energy: thermie programme action

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1995-12-31

    This book presents the activities of the Thermie programme action on application of Solar thermal energy. The main aspects are: 1.- General Aspects of low temperature solar energy 2.- Case studies 2.1 Spain: Solar heating project at the Ipocampo Playa Hotel, Majorca 2.2 Denmark: egebjerggard III energy efficient building, Ballerup 2.3 France: solar hot water supply in the Bastia Hospital, Corsica 2.4 Germany: Vacuum collector for heat supply for a swimming pool in Perschen 2.5 Greece: Large solar systems technologies in Greece 2.6 Ireland: The green Building-Temple Bar, Dublin 2.7 Italy: Unglazed collectors for seasonal production of hot water-Riccione 2.8 The Netherlands: de Zwoer swimming pool, Driebergen 2.9 Portugal: Hot water production by use of solar energy in Monsanto camp site 2.10 Spain: Solar thermal installation for a single dwelling, Javea

  15. Recent trends in solar thermal sorption cooling system technology

    Directory of Open Access Journals (Sweden)

    Khaled M Bataineh

    2015-05-01

    Full Text Available Solar thermal cooling is the best alternative solution to overcome the problems associated with using nonrenewable resources. There are several thermal cooling methods developed differing from each other according to the thermodynamic cycle and type of refrigerant used. Recent developments in absorption and adsorption solar cooling systems are presented. Summarized thermodynamic modeling for both absorption and adsorption solar cooling systems is given. Brief thermal analysis among the types of solar collectors is presented. System efficiencies and optimization analysis are presented. The influences of geometrical, system configurations, and physical parameters on the performance of solar thermal sorption cooling system are investigated. The basis for the design of absorption and adsorption solar cooling systems is provided. Several case studies in different climatic conditions are presented. Economic feasibility for both systems is discussed. Comparison between the absorption and adsorption solar cooling system is summarized.

  16. Report on the symposium and workshop on the 5 MWt solar thermal test facility

    Energy Technology Data Exchange (ETDEWEB)

    1976-01-01

    Design concepts and applications for the 5 MWt Solar Thermal Test Facility at Albuquerque are discussed in 43 papers. Session topics include central receivers, solar collectors, solar energy storage, high temperature materials and chemistry. A program overview and individual contractor reports for the test facility project are included, along with reports on conference workshop sessions and users group recommendations. A list of conference attendees is appended. Separate abstracts are prepared for 39 papers.

  17. Experimental investigation into a packed bed thermal storage solution for solar gas turbine systems

    CSIR Research Space (South Africa)

    Klein, P

    2013-09-01

    Full Text Available High temperature thermal storage in randomly packed beds of ceramic particles is proposed as an effective storage solution for Solar Gas Turbine (SGT) cycles in the near term. Numerical modelling of these systems allows for optimised thermal storage...

  18. Solar energy control system. [temperature measurement

    Science.gov (United States)

    Currie, J. R. (Inventor)

    1981-01-01

    A solar energy control system for a hot air type solar energy heating system wherein thermocouples are arranged to sense the temperature of a solar collector, a space to be heated, and a top and bottom of a heat storage unit is disclosed. Pertinent thermocouples are differentially connected together, and these are employed to effect the operation of dampers, a fan, and an auxiliary heat source. In accomplishing this, the differential outputs from the thermocouples are amplified by a single amplifier by multiplexing techniques. Additionally, the amplifier is corrected as to offset by including as one multiplex channel a common reference signal.

  19. The thermal infrared continuum in solar flares

    Science.gov (United States)

    Fletcher, Lyndsay; Simoes, Paulo; Kerr, Graham Stewart; Hudson, Hugh S.; Gimenez de Castro, C. Guillermo; Penn, Matthew J.

    2017-08-01

    Observations of the Sun with the Atacama Large Millimeter Array have now started, and the thermal infrared will regularly be accessible from the NSF’s Daniel K. Inouye Solar Telescope. Motivated by the prospect of these new observations, and by recent flare detections in the mid infrared, we set out here to model and understand the source of the infrared continuum in flares, and to explore its diagnostic capability for the physical conditions in the flare atmosphere. We use the 1D radiation hydrodynamics code RADYN to calculate mid-infrared continuum emission from model atmospheres undergoing sudden deposition of energy by non-thermal electrons. We identify and characterise the main continuum thermal emission processes relevant to flare intensity enhancement in the mid- to far-infrared (2-200 micron) spectral range as free-free emission on neutrals and ions. We find that the infrared intensity evolution tracks the energy input to within a second, albeit with a lingering intensity enhancement, and provides a very direct indication of the evolution of the atmospheric ionization. The prediction of highly impulsive emission means that, on these timescales, the atmospheric hydrodynamics need not be considered in analysing the mid-IR signatures.

  20. Biaxial-Type Concentrated Solar Tracking System with a Fresnel Lens for Solar-Thermal Applications

    Directory of Open Access Journals (Sweden)

    Tsung Chieh Cheng

    2016-04-01

    Full Text Available In this paper, an electromechanical, biaxial-type concentrated solar tracking system was designed for solar-thermal applications. In our tracking system, the sunlight was concentrated by the microstructure of Fresnel lens to the heating head of the Stirling engine and two solar cells were installed to provide the power for tracking system operation. In order to obtain the maximum sun power, the tracking system traces the sun with the altitude-azimuth biaxial tracing method and accurately maintains the sun’s radiation perpendicular to the plane of the heating head. The results indicated that the position of heating head is an important factor for power collection. If the sunlight can be concentrated to completely cover the heating head with small heat loss, we can obtain the maximum temperature of the heating head of the Stirling engine. Therefore, the temperature of heating head can be higher than 1000 °C in our experiment on a sunny day. Moreover, the results also revealed that the temperature decrease of the heating head is less than the power decrease of solar irradiation because of the latent heat of copper and the small heat loss from the heating head.

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

    OpenAIRE

    Smajo Sulejmanovic; Suad Kunosic; Ema Hankic

    2014-01-01

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

  2. Novel solar air Heater for high temperatures; Novedoso Calentador solar de aire para altas temperaturas

    Energy Technology Data Exchange (ETDEWEB)

    Rincon, E. A.; Duran, M. D.; Lentz, A. E.

    2008-07-01

    A novel solar air heater that allows to reach temperatures of the order of 100 degree centigrade with thermal efficiencies superior to 50% due to a solar concentrator and the reduction of thermal losses from the air when circulating between the absorber and mirrors of section of circular arc, well isolated of the outside surrounding. The receiver consists of a concentrator with wedges of plastic transparency that make the function of lenses. The light refracted by the wedges enters to a series of concentrators PC type truncated optimally so that the space among them allows the positioning of the absorber, who are covered metallic segments with selective film. Its excellent performance makes ideals applications as Sauna bath, the drying at high temperature, and systems for conditioning of air. (Author)

  3. Review of Mid- to High-Temperature Solar Selective Absorber Materials

    Energy Technology Data Exchange (ETDEWEB)

    Kennedy, C. E.

    2002-07-01

    This report describes the concentrating solar power (CSP) systems using solar absorbers to convert concentrated sunlight to thermal electric power. It is possible to achieve solar absorber surfaces for efficient photothermal conversion having high solar absorptance (a) for solar radiation and a low thermal emittance (e) at the operational temperature. A low reflectance (?'' 0) at wavelengths (?) 3 mm and a high reflectance (?'' 1) at l 3 mm characterize spectrally selective surfaces. The operational temperature ranges of these materials for solar applications can be categorized as low temperature (T< 100 C), mid-temperature (100 C< T< 400 C), and high-temperature (T> 400 C). High- and mid-temperature applications are needed for CSP applications. For CSP applications, the ideal spectrally selective surface would be low-cost and easy to manufacture, chemically and thermally stable in air at elevated operating temperatures (T= 500 C), and have a solar absorptance= 0.98 and a thermal emittance= 0.05 at 500 C.

  4. Heat engine development for solar thermal power systems

    Science.gov (United States)

    Pham, H. Q.; Jaffe, L. D.

    1981-01-01

    The technical status of three heat engines (Stirling, high-temperature Brayton, and Combined cycle) for use in solar thermal power systems is presented. Performance goals necessary to develop a system competitive with conventional power requirements include an external heated engine output less than 40 kW, and efficiency power conversion subsystem at least 40% at rated output, and a half-power efficiency of at least 37%. Results show that the Stirling engine can offer a 39% efficiency with 100 hours of life, and a 20% efficiency with 10,000 hours of life, but problems with seals and heater heads exist. With a demonstrated efficiency near 31% at 1500 F and a minimum lifetime of 100,000 hours, the Brayton engine does not offer sufficient engine lifetime, efficiency, and maintenance for solar thermal power systems. Examination of the Rankine bottoming cycle of the Combined cycle engine reveals a 30 year lifetime, but a low efficiency. Additional development of engines for solar use is primarily in the areas of components to provide a long lifetime, high reliability, and low maintenance (no more than $0.001/kW-hr).

  5. The role of Solar thermal in Future Energy Systems

    DEFF Research Database (Denmark)

    Mathiesen, Brian Vad; Hansen, Kenneth

    2017-01-01

    This report deals with solar thermal technologies and investigates possible roles for solar thermal in future energy systems for four national energy systems; Germany, Austria, Italy and Denmark. The project period started in January 2014 and finished by October 2017. This report is based...

  6. MGS SAMPLER THERMAL EMISSION SPECTROMETER GLOBAL TEMPERATURE

    Data.gov (United States)

    National Aeronautics and Space Administration — This archive contains Thermal Emission Spectrometer (TES) 25-micron global surface temperature data, collected during the ANS portion of the Mars Global Surveyor...

  7. High Temperature Fiberoptic Thermal Imaging System Project

    Data.gov (United States)

    National Aeronautics and Space Administration — The proposed Phase 1 program will fabricate and demonstrate a small diameter single fiber endoscope that can perform high temperature thermal imaging in a jet engine...

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

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2007-12-14

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

  9. Rankine-Brayton engine powered solar thermal aircraft

    Science.gov (United States)

    Bennett, Charles L [Livermore, CA

    2009-12-29

    A solar thermal powered aircraft powered by heat energy from the sun. A Rankine-Brayton hybrid cycle heat engine is carried by the aircraft body for producing power for a propulsion mechanism, such as a propeller or other mechanism for enabling sustained free flight. The Rankine-Brayton engine has a thermal battery, preferably containing a lithium-hydride and lithium mixture, operably connected to it so that heat is supplied from the thermal battery to a working fluid. A solar concentrator, such as reflective parabolic trough, is movably connected to an optically transparent section of the aircraft body for receiving and concentrating solar energy from within the aircraft. Concentrated solar energy is collected by a heat collection and transport conduit, and heat transported to the thermal battery. A solar tracker includes a heliostat for determining optimal alignment with the sun, and a drive motor actuating the solar concentrator into optimal alignment with the sun based on a determination by the heliostat.

  10. Rankline-Brayton engine powered solar thermal aircraft

    Science.gov (United States)

    Bennett, Charles L [Livermore, CA

    2012-03-13

    A solar thermal powered aircraft powered by heat energy from the sun. A Rankine-Brayton hybrid cycle heat engine is carried by the aircraft body for producing power for a propulsion mechanism, such as a propeller or other mechanism for enabling sustained free flight. The Rankine-Brayton engine has a thermal battery, preferably containing a lithium-hydride and lithium mixture, operably connected to it so that heat is supplied from the thermal battery to a working fluid. A solar concentrator, such as reflective parabolic trough, is movably connected to an optically transparent section of the aircraft body for receiving and concentrating solar energy from within the aircraft. Concentrated solar energy is collected by a heat collection and transport conduit, and heat transported to the thermal battery. A solar tracker includes a heliostat for determining optimal alignment with the sun, and a drive motor actuating the solar concentrator into optimal alignment with the sun based on a determination by the heliostat.

  11. Measuring nanowire thermal conductivity at high temperatures

    Science.gov (United States)

    Wang, Xiaomeng; Yang, Juekuan; Xiong, Yucheng; Huang, Baoling; Xu, Terry T.; Li, Deyu; Xu, Dongyan

    2018-02-01

    This work extends the micro-thermal-bridge method for thermal conductivity measurements of nanowires to high temperatures. The thermal-bridge method, based on a microfabricated device with two side-by-side suspended membranes with integrated platinum resistance heaters/thermometers, has been used to determine thermal conductivity of various nanowires/nanotubes/nanoribbons at relatively low temperatures. However, to date, thermal conductivity characterization of nanowires at temperatures above 600 K has seldom been reported presumably due to several technical difficulties including the instability of the microfabricated thermometers, radiation heat loss, and the effect of the background conductance on the measurement. Here we report on our attempt to address the aforementioned challenges and demonstrate thermal conductivity measurement of boron nanoribbons up to 740 K. To eliminate high temperature resistance instability, the device is first annealed at 1023 K for 5 min in an argon atmosphere. Two radiation shields are installed in the measurement chamber to minimize radiation heat loss from the measurement device to the surroundings; and the temperature of the device at each set point is calibrated by an additional thermocouple directly mounted on the chip carrier. The effect of the background conductance is eliminated by adopting a differential measurement scheme. With all these modifications, we successfully measured the thermal conductivity of boron nanoribbons over a wide temperature range from 27 K to 740 K. The measured thermal conductivity increases monotonically with temperature and reaches a plateau of ~2.5 W m‑1 K‑1 at approximately 400 K, with no clear signature of Umklapp scattering observed in the whole measurement temperature range.

  12. Graphene-enhanced thermal interface materials for heat removal from photovoltaic solar cells

    Science.gov (United States)

    Saadah, M.; Gamalath, D.; Hernandez, E.; Balandin, A. A.

    2016-09-01

    The increase in the temperature of photovoltaic (PV) solar cells affects negatively their power conversion efficiency and decreases their lifetime. The negative effects are particularly pronounced in concentrator solar cells. Therefore, it is crucial to limit the PV cell temperature by effectively removing the excess heat. Conventional thermal phase change materials (PCMs) and thermal interface materials (TIMs) do not possess the thermal conductivity values sufficient for thermal management of the next generation of PV cells. In this paper, we report the results of investigation of the increased efficiency of PV cells with the use of graphene-enhanced TIMs. Graphene reveals the highest values of the intrinsic thermal conductivity. It was also shown that the thermal conductivity of composites can be increased via utilization of graphene fillers. We prepared TIMs with up to 6% of graphene designed specifically for PV cell application. The solar cells were tested using the solar simulation module. It was found that the drop in the output voltage of the solar panel under two-sun concentrated illumination can be reduced from 19% to 6% when grapheneenhanced TIMs are used. The proposed method can recover up to 75% of the power loss in solar cells.

  13. Transient Simulation of Line-Focus Solar Thermal Power Plants

    OpenAIRE

    do amaral Burghi, Ana Carolina

    2016-01-01

    Concentrated Solar Power (CSP) is a utility scale technology that pro duces electricity using the thermal energy of the sun. Due to the varying intensity of the solar irradiation, there is a constant change in the op eration point for solar thermal power plants. In order to optimize the process, a complex relation between irradiation intensity, fluid mass fl ow and collector focus must be considered and appropriate control strategies should take into account the transient...

  14. Nonimaging concentrators for solar thermal energy. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Winston, R.

    1980-03-21

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

  15. Investigation of lithium sulphate for high temperature thermal energy storage

    Science.gov (United States)

    Bayon, Alicia; Liu, Ming; Bruno, Frank; Hinkley, Jim

    2017-06-01

    Lithium sulphate (Li2SO4) was evaluated as a solid-solid PCM material to be coupled with concentrated solar power (CSP) technologies. The energy is stored in a cubic crystalline phase that is formed at temperatures above 576°C and can potentially be discharged at temperatures as low as 150°C, providing both sensible and latent thermal energy storage in a hybrid sensible-latent system. These operational conditions are appropriate for current CSP technologies based on subcritical steam Rankine power cycles. Results from thermal cycling experiments in air showed no change in energy storage capacity after 15 cycles. There was up to a 5% reduction in latent thermal capacity and 0.95% in total thermal capacity after 150 cycles in air. In our paper, we evaluate a hybrid sensible-latent thermal energy storage system based on lithium sulphate from an economic and technical performance point of view, demonstrating its potential as a high temperature thermal energy storage material.

  16. Thermal Field Analysis and Simulation of an Infrared Belt Furnace Used for Solar Cells

    Directory of Open Access Journals (Sweden)

    Bai Lu

    2014-01-01

    Full Text Available During solar cell firing, volatile organic compounds (VOC and a small number of metal particles were removed using the gas flow. When the gas flow was disturbed by the thermal field of infrared belt furnace and structure, the metal particles in the discharging gas flow randomly adhered to the surface of solar cell, possibly causing contamination. Meanwhile, the gas flow also affected the thermal uniformity of the solar cell. In this paper, the heating mechanism of the solar cell caused by radiation, convection, and conduction during firing was analyzed. Afterward, four 2-dimensional (2D models of the furnace were proposed. The transient thermal fields with different gas inlets, outlets, and internal structures were simulated. The thermal fields and the temperature of the solar cell could remain stable and uniform when the gas outlets were installed at the ends and in the middle of the furnace, with the gas inlets being distributed evenly. To verify the results, we produced four types of furnaces according to the four simulated results. The experimental results indicated that the thermal distribution of the furnace and the characteristics of the solar cells were consistent with the simulation. These experiments improved the efficiency of the solar cells while optimizing the solar cell manufacturing equipment.

  17. Thermal losses od solar distiller assisted with accumulator solar collector; Perdidas termicas del destilador solar asistido con colector solar acumalador

    Energy Technology Data Exchange (ETDEWEB)

    Esteban, C.; Fasulo, A.; Franco, J.

    2004-07-01

    In the Laboratory of Solar Energy of the National University of San Luis (Argentina), we have developed and tested a solar collector accumulator of simple characteristics. The same one consists in a tank of stainless steel, covered with black paint, circular section, and thermically protected with several layers of alveolar polycarbonate. It was considered that a good application for this device would be the feeding thermal assistant for a basin-type distiller. It was constructed and the new solar distiller's behavior was evaluated. With the purpose of introducing improvements in the new still we study their thermal losses. We find that to increase the efficiency of the new device it is necessary: to diminish the thermal losses increasing the insulation, and to increase the efficiency in the collection of solar radiation. (Author)

  18. A model for managing and evaluating solar radiation for indoor thermal comfort

    Energy Technology Data Exchange (ETDEWEB)

    La Gennusa, Maria; Rizzo, Gianfranco [Dipartimento di Ricerche Energetiche ed Ambientali (DREAM), Universita degli Studi di Palermo, Viale delle Scienze, 90128 Palermo (Italy); Nucara, Antonino; Pietrafesa, Matilde [Dipartimento di Informatica, Matematica, Elettronica e Trasporti (DIMET), Universita Mediterranea di Reggio Calabria, Feo di Vito, 89060 Reggio Calabria (Italy)

    2007-05-15

    Thermal comfort of people occupying indoor spaces depends, to a large extent, on the direct component of solar radiation incident on the human body. In turn, even the diffuse component of the solar radiation could affect the thermal sensations of people. Despite this evidence, at the present there is a lack in the availability of simple and reliable methods capable of taking into account the influence of the solar radiation on thermal balance in the human body. In this work a comprehensive method is presented for the computation of the mean radiant temperature of people in thermal moderate indoor environments in the presence of solar radiation. The effects produced on the amount of solar radiation entering rooms in the presence of shadowing devices are also analysed. Finally, an application of the method is provided for a non-parallelepiped room equipped with a south window: results are shown in terms of the mean radiant temperature. A simple evaluation of thermal comfort conditions, referring to the present international standards, is also provided. The model can be easily linked to the computerized methods for analyzing the thermal behaviour of buildings, and is intended as a support for the thermal comfort evaluation methods. (author)

  19. Reduction of temperature in silicon photovoltaic module using thermal radiation coating

    Directory of Open Access Journals (Sweden)

    Nakamura Satoshi

    2016-01-01

    Full Text Available The temperature of solar cells increases under the actual operating conditions, and the conversion efficiency of solar cells decreases with increasing temperature. In this study, a thermal radiation layer was coated on the back sheet of the PV module by a spray coating method and the effect was evaluated. The thickness of the layer was 30 μm. The temperature of the PV module with the thermal radiation coating was lower than that of the PV module without the thermal radiation coating. And the operating temperature range of the PV module with the thermal radiation coating was decreased by 2~3°C. The open-circuit voltage of the PV module with the thermal radiation coating was 0.1 V higher than that of the module without the coating due to the thermal radiation coating.

  20. Active thermal isolation for temperature responsive sensors

    Science.gov (United States)

    Martinson, Scott D. (Inventor); Gray, David L. (Inventor); Carraway, Debra L. (Inventor); Reda, Daniel C. (Inventor)

    1994-01-01

    The detection of flow transition between laminar and turbulent flow and of shear stress or skin friction of airfoils is important in basic research for validation of airfoil theory and design. These values are conventionally measured using hot film nickel sensors deposited on a polyimide substrate. The substrate electrically insulates the sensor and underlying airfoil but is prevented from thermally isolating the sensor by thickness constraints necessary to avoid flow contamination. Proposed heating of the model surface is difficult to control, requires significant energy expenditures, and may alter the basic flow state of the airfoil. A temperature responsive sensor is located in the airflow over the specified surface of a body and is maintained at a constant temperature. An active thermal isolator is located between this temperature responsive sensor and the specific surface of the body. The total thickness of the isolator and sensor avoid any contamination of the flow. The temperature of this isolator is controlled to reduce conductive heat flow from the temperature responsive sensor to the body. This temperature control includes (1) operating the isolator at the same temperature as the constant temperature of the sensor; and (2) establishing a fixed boundary temperature which is either less than or equal to, or slightly greater than the sensor constant temperature. The present invention accordingly thermally isolates a temperature responsive sensor in an energy efficient, controllable manner while avoiding any contamination of the flow.

  1. 20. symposium on thermal solar energy. Proceedings; 20. Symposium Thermische Solarenergie. Tagungsband

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2010-07-01

    analyses and quality analysis of 120 solar systems in the storey residential construction as well as in commercial applications (Christian Fink); (18) Ecodesign requirements and energy label for solar thermal power plants - State of the discussion, risks and chances (Uwe Trenkner); (19) Legal framework for large solar thermal power plants - Presentation of the results of a study on behalf of the BMU (Margarete von Oppen); (20) Solar thermal power plants on multiple family building - A new market arises. (Dirk Mangold); (21) Simulation of air collector systems in TSOL (Sebastian Engelhardt); (22) Simulation of heat pumps in connection with solar thermal power plants (Jens Rudolf); (23) Sensibility analysis of thermosyphonic solar thermal power plants using Matlab/Simulink and CARNOT (Sebastian Brandmayr), (24) Optimization of the irradiation by an adaptive arrangement and tracking, respectively (Stephan A. Mathez); (25) Tandem lecture: Concept and implementation of a solar zero energy building (Stephan Fabi); (26) Energy power house - Retrofitting to a plus energy office building (Mathias Schlosser); (27) The winner building in Solar Decathlon 2009 (USA) (Johanna Henrich); (28) DESERTEC - Sustainable Electricity for Europe, Middle East and North Africa (Hans Mueller-Steinhagen); (29) LowEx District heating - Reduction of the grid temperature for enhancing the opportunities of regenerative energy (Karin Ruehling); (30) Solar and heat pump systems - IEA SHC Task 44 and HPP (Jean-Christophe Hadorn); (31) Solar assisted DEC plant ENERGYbase, Vienna: Evaluation of the plant by the Comparison TRNSYS - Simulation with monitoring results for the summer 2009 (Anita Preisler); (32) Long term monitoring of a solar thermal power plant for supporting the refrigeration supply of an office building and administrative building (Klaus Huber); (33) Solar thermal energy and heat pumps - Experiences from 3 heating periods - Development of a solar system operation number (Frank Thole); (34

  2. Thermal performance of a single-basin solar still integrated with a shallow solar pond

    Energy Technology Data Exchange (ETDEWEB)

    El-Sebaii, A.A.; Ramadan, M.R.I.; Aboul-Enein, S.; Salem, N. [Department of Physics, Faculty of Science, Tanta University, Tanta (Egypt)

    2008-10-15

    In an attempt to improve the daily productivity of the single effect solar stills, a single-slope single-basin solar still integrated with a shallow solar pond (SSP) was studied to perform solar distillation at a relatively high temperature. The energy balance equations of various elements of the considered system were formulated and solved analytically. Suitable computer programs were prepared for optimizing and predicting the thermal performance of the considered system. Numerical calculations were carried out on typical summer and winter days in Tanta (latitude 30 47'N) for different thicknesses and mass flow rates of the flowing water to study the effect of these parameters on the daily productivity and efficiency of the system. To validate the proposed theoretical model, comparisons between calculated and measured results were carried out. Good agreement has been achieved. The year-round performances of the still with and without the SSP were also investigated. The optimum values of the flowing water thickness and the mass flow rate for this typical configuration of the SSP-active solar still were obtained as 0.03 m and 0.0009 kg/s. The annual average values of the daily productivity anti P{sub d} and efficiency anti {eta}{sub d} of the still with the SSP were found to be higher than those obtained without the SSP by 52.36% and 43.80%, respectively. (author)

  3. Optimum hot water temperature for absorption solar cooling

    Energy Technology Data Exchange (ETDEWEB)

    Lecuona, A.; Ventas, R.; Venegas, M.; Salgado, R. [Dpto. Ingenieria Termica y de Fluidos, Universidad Carlos III de Madrid, Avda. Universidad 30, 28911 Leganes, Madrid (Spain); Zacarias, A. [ESIME UPA, IPN, Av. de las Granjas 682, Col. Santa Catarina, 02550, D.F. Mexico (Mexico)

    2009-10-15

    The hot water temperature that maximizes the overall instantaneous efficiency of a solar cooling facility is determined. A modified characteristic equation model is used and applied to single-effect lithium bromide-water absorption chillers. This model is based on the characteristic temperature difference and serves to empirically calculate the performance of real chillers. This paper provides an explicit equation for the optimum temperature of vapor generation, in terms of only the external temperatures of the chiller. The additional data required are the four performance parameters of the chiller and essentially a modified stagnation temperature from the detailed model of the thermal collector operation. This paper presents and discusses the results for small capacity machines for air conditioning of homes and small buildings. The discussion highlights the influence of the relevant parameters. (author)

  4. Thermal buffering of receivers for parabolic dish solar thermal power plants

    Science.gov (United States)

    Manvi, R.; Fujita, T.; Gajanana, B. C.; Marcus, C. J.

    A parabolic dish solar thermal power plant comprises a field of parabolic dish power modules where each module is composed of a two-axis tracking parabolic dish concentrator which reflects sunlight (insolation) into the aperture of a cavity receiver at the focal point of the dish. The heat generated by the solar flux entering the receiver is removed by a heat transfer fluid. In the dish power module, this heat is used to drive a small heat engine/generator assembly which is directly connected to the cavity receiver at the focal point. A computer analysis is performed to assess the thermal buffering characteristics of receivers containing sensible and latent heat thermal energy storage. Parametric variations of the thermal inertia of the integrated receiver-buffer storage systems coupled with different fluid flow rate control strategies are carried out to delineate the effect of buffer storage, the transient response of the receiver-storage systems and corresponding fluid outlet temperature. It is concluded that addition of phase change buffer storage will substantially improve system operational characteristics during periods of rapidly fluctuating insolation due to cloud passage.

  5. Selective solar absorber emittance measurement at elevated temperature

    Science.gov (United States)

    Giraud, Philémon; Braillon, Julien; Raccurt, Olivier

    2017-06-01

    Durability of solar components for CSP (Concentrated Solar Power Plant) technologies is a key point to lower cost and ensure their large deployment. These technologies concentrated the solar radiation by means of mirrors on a receiver tube where it is collected as thermal energy. The absorbers are submitted to strong environmental constraints and the degradation of their optical properties (emittance and solar absorbance) have a direct impact on performance. The characterization of a material in such condition is complicated and requires advanced apparatuses, and different measurement methods exist for the determination of the two quantities of relevance regarding an absorber, which are its emittance and its solar absorbance. The objective is to develop new optical equipment for measure the emittance of this solar absorber at elevated temperature. In this paper, we present an optical bench developed for emittance measurement on absorbers is conditions of use. Results will be shown, with a discussion of some factors of influence over this measurement and how to control them.

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

    Science.gov (United States)

    Iasiello, M.; Braimakis, K.; Andreozzi, A.; Karellas, S.

    2017-11-01

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

  7. The effect of ambient temperature and solar panel's surface ...

    African Journals Online (AJOL)

    The absorbance layer employed in the production of the solar panel is assumed to be responsible for the high temperatures retained on the solar panel's surface when compared with the ambient temperatures. The results show that the lower the temperature difference between solar panel's surface temperature and ...

  8. The Effect of Booster-Mirror Reflector on the Thermal Performance of a Truncated Pyramid Solar Thermal Cooker

    OpenAIRE

    I. L. Mohammed; Aliyu, M. M.

    2014-01-01

    In this paper, the results and analysis of the performance of a truncated pyramid solar thermal cooker under two conditions are presented: booster-mirror reflector covered with black cloth, and booster-mirror reflector exposed to solar radiation. Results of the thermal performance tests show respective stagnation absorber plate temperatures of 145 oC and 137 oC. First/Second Figures of Merit are 0.120/0.346 and 0.125/0.400 respectively. The total heating times of 5.2 kg of wate...

  9. INFORMATION SUPPLY FOR SOLAR THERMAL SYSTEMS MATHEMATICAL MODELING

    Directory of Open Access Journals (Sweden)

    Kitaytseva Elena Khalilovna

    2017-07-01

    Full Text Available Solar thermal system are its constituent elements with their connection between each other, thermal processes within them and also input/output data. The conjunction of external and internal factors determines the efficiency of solar thermal system. No excess heat as well as its deficiency displays us high level efficiency of system. The initial data for modeling of solar thermal systems functioning are dissimilar. Parameters of system’s equipment are constant. Solar radiation amount and water consumption are variable data. The more close initial data to reality, the more definite simulated result is. The main problem is in unpredictability of water consumption by the reason of daily regime and requirement of each user. In this way user is the most instable element of the system. In this study the input data for mathematical modeling of solar thermal systems was analyzed. The climatic databases and standard specifications of hot water demand were also analyzed. The operability estimation method for solar thermal systems with variable input data was offered. The extent of suitability of any solar thermal system can be defined by certain characteristic. The value of this characteristic displays energy accumulation process.

  10. Yearly thermal performances of solar heating plants in Denmark – Measured and calculated

    DEFF Research Database (Denmark)

    Furbo, Simon; Dragsted, Janne; Perers, Bengt

    2018-01-01

    The thermal performance of solar collector fields depends mainly on the mean solar collector fluid temperature of the collector field and on the solar radiation. For Danish solar collector fields for district heating the measured yearly thermal performances per collector area varied in the period...... 2012–2016 between 313 kWh/m2 and 577 kWh/m2, with averages between 411 kWh/m2 and 463 kWh/m2. The percentage difference between the highest and lowest measured yearly thermal performance is about 84%. Calculated yearly thermal performances of typically designed large solar collector fields at six...... different locations in Denmark with measured weather data for the years 2002–2010 vary between 405 kWh/m2 collector and 566 kWh/m2 collector, if a mean solar collector fluid temperature of 60 °C is assumed. This corresponds to a percentage difference between the highest and lowest calculated yearly thermal...

  11. Multiscale computational modeling of a radiantly driven solar thermal collector

    Science.gov (United States)

    Ponnuru, Koushik

    The objectives of the master's thesis are to present, discuss and apply sequential multiscale modeling that combines analytical, numerical (finite element-based) and computational fluid dynamic (CFD) analysis to assist in the development of a radiantly driven macroscale solar thermal collector for energy harvesting. The solar thermal collector is a novel green energy system that converts solar energy to heat and utilizes dry air as a working heat transfer fluid (HTF). This energy system has important advantages over competitive technologies: it is self-contained (no energy sources are needed), there are no moving parts, no oil or supplementary fluids are needed and it is environmentally friendly since it is powered by solar radiation. This work focuses on the development of multi-physics and multiscale models for predicting the performance of the solar thermal collector. Model construction and validation is organized around three distinct and complementary levels. The first level involves an analytical analysis of the thermal transpiration phenomenon and models for predicting the associated mass flow pumping that occurs in an aerogel membrane in the presence of a large thermal gradient. Within the aerogel, a combination of convection, conduction and radiation occurs simultaneously in a domain where the pore size is comparable to the mean free path of the gas molecules. CFD modeling of thermal transpiration is not possible because all the available commercial CFD codes solve the Navier Stokes equations only for continuum flow, which is based on the assumption that the net molecular mass diffusion is zero. However, thermal transpiration occurs in a flow regime where a non-zero net molecular mass diffusion exists. Thus these effects are modeled by using Sharipov's [2] analytical expression for gas flow characterized by high Knudsen number. The second level uses a detailed CFD model solving Navier Stokes equations for momentum, heat and mass transfer in the various

  12. Cacao roasting in rural areas of Peru using concentrated solar thermal energy: experimental results

    Directory of Open Access Journals (Sweden)

    Veynandt François

    2016-01-01

    Full Text Available Solar food processing is gaining interest for income generation. Our solar cacao roaster, designed for rural areas, consists in a horizontal rotating drum, opened at one end to collect solar radiation from Scheffler concentrators of 2.7 or 8 m2. The experimental results presented bring knowledge on the system's behavior and optimal operation. The influence of the most significant parameters is studied: quantity of cacao, absorptivity of drum's coating, thermal insulation, inclination and rotational speed of the drum. Cacao temperature and direct solar irradiance are monitored to evaluate the performance in roasting time per kilogram of cacao.

  13. Thermal performance of solar district heating plants in Denmark

    DEFF Research Database (Denmark)

    Furbo, Simon; Perers, Bengt; Bava, Federico

    2014-01-01

    The market for solar heating plants connected to district heating systems is expanding rapidly in Denmark. It is expected that by the end of 2014 the 10 largest solar heating plants in Europe will be located in Denmark. Measurements from 23 Danish solar heating plants, all based on flat plate solar...... collectors mounted on the ground, shows measured yearly thermal performances of the solar heating plants placed in the interval from 313 kWh/m² collector to 493 kWh/m² collector with averages for all plants of 411 kWh/m² collector for 2012 and 450 kWh/m² collector for 2013. Theoretical calculations show...... of the cost/performance ratio for solar collector fields, both with flat plate collectors and with concentrating tracking solar collectors. It is recommended to continue monitoring and analysis of all large solar heating plants to document the reliability of the solar heating plants. It is also recommended...

  14. Solar Eclipse Effect on Shelter Air Temperature

    Science.gov (United States)

    Segal, M.; Turner, R. W.; Prusa, J.; Bitzer, R. J.; Finley, S. V.

    1996-01-01

    Decreases in shelter temperature during eclipse events were quantified on the basis of observations, numerical model simulations, and complementary conceptual evaluations. Observations for the annular eclipse on 10 May 1994 over the United States are presented, and these provide insights into the temporal and spatial changes in the shelter temperature. The observations indicated near-surface temperature drops of as much as 6 C. Numerical model simulations for this eclipse event, which provide a complementary evaluation of the spatial and temporal patterns of the temperature drops, predict similar decreases. Interrelationships between the temperature drop, degree of solar irradiance reduction, and timing of the peak eclipse are also evaluated for late spring, summer, and winter sun conditions. These simulations suggest that for total eclipses the drops in shelter temperature in midlatitudes can be as high as 7 C for a spring morning eclipse.

  15. Hierarchical Graphene Foam for Efficient Omnidirectional Solar-Thermal Energy Conversion.

    Science.gov (United States)

    Ren, Huaying; Tang, Miao; Guan, Baolu; Wang, Kexin; Yang, Jiawei; Wang, Feifan; Wang, Mingzhan; Shan, Jingyuan; Chen, Zhaolong; Wei, Di; Peng, Hailin; Liu, Zhongfan

    2017-10-01

    Efficient solar-thermal energy conversion is essential for the harvesting and transformation of abundant solar energy, leading to the exploration and design of efficient solar-thermal materials. Carbon-based materials, especially graphene, have the advantages of broadband absorption and excellent photothermal properties, and hold promise for solar-thermal energy conversion. However, to date, graphene-based solar-thermal materials with superior omnidirectional light harvesting performances remain elusive. Herein, hierarchical graphene foam (h-G foam) with continuous porosity grown via plasma-enhanced chemical vapor deposition is reported, showing dramatic enhancement of broadband and omnidirectional absorption of sunlight, which thereby can enable a considerable elevation of temperature. Used as a heating material, the external solar-thermal energy conversion efficiency of the h-G foam impressively reaches up to ≈93.4%, and the solar-vapor conversion efficiency exceeds 90% for seawater desalination with high endurance. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  16. Beam-Forming Concentrating Solar Thermal Array Power Systems

    Science.gov (United States)

    Cwik, Thomas A. (Inventor); Dimotakis, Paul E. (Inventor); Hoppe, Daniel J. (Inventor)

    2016-01-01

    The present invention relates to concentrating solar-power systems and, more particularly, beam-forming concentrating solar thermal array power systems. A solar thermal array power system is provided, including a plurality of solar concentrators arranged in pods. Each solar concentrator includes a solar collector, one or more beam-forming elements, and one or more beam-steering elements. The solar collector is dimensioned to collect and divert incoming rays of sunlight. The beam-forming elements intercept the diverted rays of sunlight, and are shaped to concentrate the rays of sunlight into a beam. The steering elements are shaped, dimensioned, positioned, and/or oriented to deflect the beam toward a beam output path. The beams from the concentrators are converted to heat at a receiver, and the heat may be temporarily stored or directly used to generate electricity.

  17. Experimental Study on Solar Cooling Tube Using Thermal/Vacuum Emptying Method

    Directory of Open Access Journals (Sweden)

    Huizhong Zhao

    2012-01-01

    Full Text Available A solar cooling tube using thermal/vacuum emptying method was experimentally studied in this paper. The coefficient of performance (COP of the solar cooling tube was mostly affected by the vacuum degree of the system. In past research, the thermal vacuum method, using an electric oven and iodine-tungsten lamp to heat up the adsorbent bed and H2O vapor to expel the air from the solar cooling tube, was used to manufacture solar cooling tubes. This paper presents a novel thermal vacuum combined with vacuum pump method allowing an increased vacuum state for producing solar cooling tubes. The following conclusions are reached: the adsorbent bed temperature of solar cooling tube could reaches up to 233°C, and this temperature is sufficient to meet desorption demand; the refrigerator power of a single solar cooling tube varies from 1 W to 12 W; the total supply refrigerating capacity is about 287 kJ; and the COP of this solar cooling tube is about 0.215.

  18. Study on effectiveness of continuous solar dryer integrated with desiccant thermal storage for drying cocoa beans

    Directory of Open Access Journals (Sweden)

    Sari Farah Dina

    2015-03-01

    Full Text Available The main objective is to assess effectiveness of continuous solar dryer integrated with desiccant thermal storage for drying cocoa beans. Two type of desiccants were tested, molecular sieve 13× (Na86 [(AlO286·(SiO2106]·264H2O as an adsorbent type and CaCl2 as an absorbent type. The results revealed that during sunshine hours, the maximum temperature within the drying chamber varied from 40 °C to 54 °C. In average, it was 9–12 °C higher than ambient temperature. These temperatures are very suitable for drying cocoa beans. During off-sunshine hours, humidity of air inside the drying chamber was lower than ambient because of the desiccant thermal storage. Drying times for intermittent directs sun drying, solar dryer integrated with adsorbent, and solar dryer integrated with absorbent were 55 h, 41 h, and 30 h, respectively. Specific energy consumptions for direct sun drying, solar dryer integrated with adsorbent, and solar dryer integrated with absorber were 60.4 MJ/kg moist, 18.94 MJ/kg moist, and 13.29 MJ/kg moist, respectively. The main conclusion can be drawn here is that a solar dryer integrated with desiccant thermal storage makes drying using solar energy more effective in term of drying time and specific energy consumption.

  19. Applicability of advanced automotive heat engines to solar thermal power

    Science.gov (United States)

    Beremand, D. G.; Evans, D. G.; Alger, D. L.

    1981-01-01

    The requirements of a solar thermal power system are reviewed and compared with the predicted characteristics of automobile engines under development. A good match is found in terms of power level and efficiency when the automobile engines, designed for maximum powers of 65-100 kW (87 to 133 hp) are operated to the nominal 20-40 kW electric output requirement of the solar thermal application. At these reduced power levels it appears that the automotive gas turbine and Stirling engines have the potential to deliver the 40+ percent efficiency goal of the solar thermal program.

  20. Solar Power Satellite Thermal Control Approach

    Science.gov (United States)

    Sacchi, E.; Cassisa, G.; Gottero, M.

    2004-12-01

    The concept of generating solar power in space and transmitting it to earth or any other desired destination such as a planet, moon, or to charge a space vehicle via microwaves, stems from a wide variety of human needs and necessities. It is now a well-known fact that world population increases at a very rapid rate, nearly 80 millions or more per year, and the world-wide energy demand seems to double in the course of the present century. If technology has to advance at the present rate, in phase with high living standards, energy growth must not lag behind. These estimates are based on the population growth rate in the developing countries and the simultaneous increase in per capita energy consumption in these countries, coupled with economical boost. In most of the underdeveloped countries energy needs are of small scales, faraway from the power distribution line and can be very easily satisfied by harnessing solar energy. Furthermore, the Earth temperature has increased by 0.5° to 1° F during the past century. This rise in temperature is believed to have been caused by the use of oil, coal, and natural gas (fossil fuels) for transportation and energy production. Actually, fossil fuel combustion-based power plants are the dominant sources for energy demands. Therefore, increased power production will accelerate the production of greenhouse gases (predominantly CO2). To cope with their energy needs, countries could be engaged in the use of nuclear energy, which could accelerate the diffusion of nuclear arms as a bye- product.

  1. Investigating effect of different reflective surfaces on solar thermal collector

    Science.gov (United States)

    Chua, Yaw Long; Chin, Kiat Keong; Tay, Tee Tiong

    2017-11-01

    This paper reports on the experiments conducted to investigate the efficiency of different type of reflecting surfaces used on solar thermal collector. Three types of commonly available reflective surfaces coated with silver colour acrylic paint, reflective aluminium foil and blank compact disc are investigated. In this paper, the effect of different reflective surfaces on the water container and parabolic concentrator dish are investigated. In the first experiment, two types of surfaces, coated with silver colour acrylic paint and black colour acrylic paint on an aluminium container are compared. The other factors that might influence the experiment outcome like the material, focal point, and weather condition are kept constant. The experiment results proved that black colour surface is better in absorbing heat reflected by the parabolic dish. The second experiment focused on investigating the effect of different reflective surfaces on the parabolic concentrator dish itself. These surfaces are tested on a parabolic disc of a static solar thermal collector that reflects heat from the sun to a body of water stored in a black colour aluminium container. The temperature of the water is measured at a predetermined interval to measure the efficiency of the reflective surfaces used. It is found that the aluminium reflective surface performed the best compared to the other surfaces.

  2. Utilization of solar thermal energy in the mining industry: applied case solar thermal systems for hot water heating - Mining camps

    Energy Technology Data Exchange (ETDEWEB)

    Vasquez Mena, Horacio [Portal Sustentable and Enerficaz (Chile)

    2010-07-01

    The paper gives an overview of how solar thermal energy can be used in the mining industry. This is done through a case study of solar thermal systems (STS) for hot water heating in mining camps in Chile. Solar thermal energy has various applications, such as heating and air conditioning. Solar radiation between 600 to 800w/m2 only can be used for solar thermal systems. Solar collectors can be of two types, flat plate or vacuum tube. Various techniques can be used to model solar thermal systems: Transol, RET screen, T-sol, Static model and F-chart. Chile has the great advantage of being one of the countries with the highest levels of solar radiation. Technical data for the solar collector and the heat pump used for the study are given. The collector performance was evaluated throughout the year and the actual results achieved were compared with those projected. The paper concludes that STS are a good source of renewable energy. They are efficient, cheap, and they have a small carbon footprint.

  3. Analysis of Low Temperature Organic Rankine Cycles for Solar Applications

    Science.gov (United States)

    Li, Yunfei

    The present work focuses on Organic Rankine Cycle (ORC) systems and their application to low temperature waste heat recovery, combined heat and power as well as off-grid solar power generation applications. As CO_2 issues come to the fore front and fossil fuels become more expensive, interest in low grade heat recovery has grown dramatically in the past few years. Solar energy, as a clean, renewable, pollution-free and sustainable energy has great potential for the use of ORC systems. Several ORC solutions have been proposed to generate electricity from low temperature sources. The ORC systems discussed here can be applied to fields such as solar thermal, biological waste heat, engine exhaust gases, small-scale cogeneration, domestic boilers, etc. The current work presents a thermodynamic and economic analysis for the use of ORC systems to convert solar energy or low exergy energy to generate electrical power. The organic working fluids investigated here were selected to investigate the effect of the fluid saturation temperature on the performance of ORCs. The working fluids under investigation are R113, R245fa, R123, with boiling points between 40°C and 200°C at pressures from 10 kPa to 10 MPa. Ambient temperature air at 20oC to 30oC is utilized as cooling resource, and allowing for a temperature difference 10°C for effective heat transfer. Consequently, the working fluids are condensed at 40°C. A combined first- and second-law analysis is performed by varying some system independent parameters at various reference temperatures. The present work shows that ORC systems can be viable and economical for the applications such as waste heat use and off-grid power generation even though they are likely to be more expensive than grid power.

  4. Standard Practice for Evaluating Thermal Insulation Materials for Use in Solar Collectors

    CERN Document Server

    American Society for Testing and Materials. Philadelphia

    1994-01-01

    1.1 This practice sets forth a testing methodology for evaluating the properties of thermal insulation materials to be used in solar collectors with concentration ratios of less than 10. Tests are given herein to evaluate the pH, surface burning characteristics, moisture adsorption, water absorption, thermal resistance, linear shrinkage (or expansion), hot surface performance, and accelerated aging. This practice provides a test for surface burning characteristics but does not provide a methodology for determining combustibility performance of thermal insulation materials. 1.2 The tests shall apply to blanket, rigid board, loose-fill, and foam thermal insulation materials used in solar collectors. Other thermal insulation materials shall be tested in accordance with the provisions set forth herein and should not be excluded from consideration. 1.3 The assumption is made that elevated temperature, moisture, and applied stresses are the primary factors contributing to the degradation of thermal insulation mat...

  5. Development and construction of the novel solar thermal desiccant cooling system incorporating hot water production

    Energy Technology Data Exchange (ETDEWEB)

    Enteria, Napoleon; Yoshino, Hiroshi; Mochida, Akashi; Takaki, Rie [Faculty of Engineering, Tohoku University, Sendai 980-8579 (Japan); Satake, Akira [Technical Research Institute, Maeda Corporation, Tokyo 179-8914 (Japan); Yoshie, Ryuichiro [Faculty of Engineering, Tokyo Polytechnic University, Atsugi 243-0297 (Japan); Baba, Seizo [Earth Clean Tohoku Co. Ltd., Sendai 984-0038 (Japan)

    2010-02-15

    This paper reports the development and construction of the novel solar cooling and heating system. The system consists of the thermal energy subsystem and the desiccant cooling subsystem. The system utilizes both the cheaper nighttime electric energy and the free daytime solar energy. The system is conceptualized to produce both cooling during summer daytime and hot water production during winter. Testing and evaluation of the system had been done to determine its operational procedure and performance. Based on the results, the thermal energy subsystem functioned to its expected performance in solar energy collection and thermal storage. The desiccant cooling subsystem reduced both the temperature and the humidity content of the air using solar energy with a minimal amount of back-up electric energy. The system however, needs further investigation under real conditions. (author)

  6. Economic optimization of a Kalina cycle for a parabolic trough solar thermal power plant

    DEFF Research Database (Denmark)

    Modi, Anish; Kærn, Martin Ryhl; Andreasen, J. G.

    2015-01-01

    technology for the conversion of solar thermal energy into electricity. In this paper, a Kalina cycle and a steam Rankine cycle are compared in terms of the total capital investment cost for use in a parabolic trough solar thermal power plant without storage. In order to minimize the total capital investment...... cost of the Kalina cycle power plant (the solar field plus the power cycle), an optimization was performed by varying the turbine outlet pressure, the separator inlet temperature and the separator inlet ammonia mass fraction. All the heat exchangers were modelled as shell and tube type using suitable......The Kalina cycle has recently seen increased interest as a replacement for the more traditional steam Rankine cycle for geothermal, solar, ocean thermal energy conversion and waste heat recovery applications. The Kalina cycle uses a mixture of ammonia and water as the working fluid. The ammonia...

  7. Energy comparison between solar thermal power plant and photovoltaic power plant

    Science.gov (United States)

    Novosel, Urška; Avsec, Jurij

    2017-07-01

    The combined use of renewable energy and alternative energy systems and better efficiency of energy devices is a promising approach to reduce effects due to global warming in the world. On the basis of first and second law of thermodynamics we could optimize the processes in the energy sector. The presented paper shows the comparison between solar thermal power plant and photovoltaic power plant in terms of energy, exergy and life cycle analysis. Solar thermal power plant produces electricity with basic Rankine cycle, using solar tower and solar mirrors to produce high fluid temperature. Heat from the solar system is transferred by using a heat exchanger to Rankine cycle. Both power plants produce hydrogen via electrolysis. The paper shows the global efficiency of the system, regarding production of the energy system.

  8. Effects of Nonuniform Incident Illumination on the Thermal Performance of a Concentrating Triple Junction Solar Cell

    Directory of Open Access Journals (Sweden)

    Fahad Al-Amri

    2014-01-01

    Full Text Available A numerical heat transfer model was developed to investigate the temperature of a triple junction solar cell and the thermal characteristics of the airflow in a channel behind the solar cell assembly using nonuniform incident illumination. The effects of nonuniformity parameters, emissivity of the two channel walls, and Reynolds number were studied. The maximum solar cell temperature sharply increased in the presence of nonuniform light profiles, causing a drastic reduction in overall efficiency. This resulted in two possible solutions for solar cells to operate in optimum efficiency level: (i adding new receiver plate with higher surface area or (ii using forced cooling techniques to reduce the solar cell temperature. Thus, surface radiation exchanges inside the duct and Re significantly reduced the maximum solar cell temperature, but a conventional plain channel cooling system was inefficient for cooling the solar cell at medium concentrations when the system was subjected to a nonuniform light distribution. Nonuniformity of the incident light and surface radiation in the duct had negligible effects on the collected thermal energy.

  9. Solar wall heating and daylight use with transparent thermal insulation - the solar environmental wall; Solare Wandheizung und Tageslichtnutzung mit Transparenter Waermedaemmung - die Solare Umweltwand

    Energy Technology Data Exchange (ETDEWEB)

    Platzer, W. [Fachverband Transparente Waermedaemmung e.V., Gundelfingen (Germany)

    2005-07-01

    Construction with the sun means to open building walls for the sun. The building is supposed to benefit directly from daylight and solar heat. Special materials were developed for this purpose, which combine solar transmission and light transmission. They enable the transparent thermal insulation of buildings, abbreviated TWD. Their integration into the facade and the roof offer an intelligent and uncomplicated technology for the use of solar energy, the ''solar environmental wall''. TWD-materials can be used as filling material in various building components and they already constitute a weather-resistant wall. They are thermally-insulating structures or materials, which keep out the heat but allow the transmission of solar radiation and light. TWD-materials maintain their excellent insulating properties almost unchanged even in case of very cold outer temperatures or inclined construction in the roof area. In these cases the convection of components that are only filled with air or gas, can lead to considerable decreases of the U-value (according to DIN EN 673 up to 45%). Good TWD-materials are resistant against humidity, which enables to use them in non-hermetic systems, such as e.g. U-profile glas, too. (orig.)

  10. Analysis of regenerative thermal storage geometries for solar gas turbines

    CSIR Research Space (South Africa)

    Klein, P

    2014-08-01

    Full Text Available Ceramic heat regenerators are suited to providing thermal storage for concentrating solar power stations based on a recuperated gas turbine cycle. Randomly packed beds of spheres and saddles; honeycombs and checker bricks were identified...

  11. Photoswitchable Molecular Rings for Solar-Thermal Energy Storage.

    Science.gov (United States)

    Durgun, E; Grossman, Jeffrey C

    2013-03-21

    Solar-thermal fuels reversibly store solar energy in the chemical bonds of molecules by photoconversion, and can release this stored energy in the form of heat upon activation. Many conventional photoswichable molecules could be considered as solar thermal fuels, although they suffer from low energy density or short lifetime in the photoinduced high-energy metastable state, rendering their practical use unfeasible. We present a new approach to the design of chemistries for solar thermal fuel applications, wherein well-known photoswitchable molecules are connected by different linker agents to form molecular rings. This approach allows for a significant increase in both the amount of stored energy per molecule and the stability of the fuels. Our results suggest a range of possibilities for tuning the energy density and thermal stability as a function of the type of the photoswitchable molecule, the ring size, or the type of linkers.

  12. Photoswichable Molecular Rings for Solar-Thermal Energy Storage

    Science.gov (United States)

    Durgun, Engin; Kolpak, Alexie M.; Grossman, Jeffrey C.

    2012-02-01

    Solar-thermal fuels reversibly store solar energy in the chemical bonds of molecules by photoconversion, and can release this stored energy in the form of heat upon activation. Many conventional photoswichable molecules could be considered as solar thermal fuels, although they suffer from low energy density and short lifetime in the photo-excited state, rendering their practical use unfeasible. We present a new approach to design systems for solar thermal fuel applications, wherein well-known photoswitchable molecules are connected by different linker agents to form molecular rings. This approach allows for a significant increase in both the amount of stored energy per molecule and the stability of the fuels. Our results suggest a range of possibilities for tuning the energy density and thermal stability as a function of the type of the photoswitchable molecule, the ring size, and/or the type of linkers.

  13. Efficient solar-driven synthesis, carbon capture, and desalinization, STEP: solar thermal electrochemical production of fuels, metals, bleach.

    Science.gov (United States)

    Licht, S

    2011-12-15

    STEP (solar thermal electrochemical production) theory is derived and experimentally verified for the electrosynthesis of energetic molecules at solar energy efficiency greater than any photovoltaic conversion efficiency. In STEP the efficient formation of metals, fuels, chlorine, and carbon capture is driven by solar thermal heated endothermic electrolyses of concentrated reactants occuring at a voltage below that of the room temperature energy stored in the products. One example is CO(2) , which is reduced to either fuels or storable carbon at a solar efficiency of over 50% due to a synergy of efficient solar thermal absorption and electrochemical conversion at high temperature and reactant concentration. CO(2) -free production of iron by STEP, from iron ore, occurs via Fe(III) in molten carbonate. Water is efficiently split to hydrogen by molten hydroxide electrolysis, and chlorine, sodium, and magnesium from molten chlorides. A pathway is provided for the STEP decrease of atmospheric carbon dioxide levels to pre-industial age levels in 10 years. Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  14. Integrated solar thermal facade component for building energy retrofit

    OpenAIRE

    Giovanardi, Alessia

    2012-01-01

    In the perspective of the "Net Zero Energy Buildings" as specified in the EPBP 2010/31/EU, herein a modular unglazed solar thermal facade component for facilitating the installation of active solar thermal facades has been conceived and designed to answer three considerations: (1) easily installable elements, offering high modularity to be sized for the specific needs of the buildings considered, (2) low-price unglazed technology, given by the industrial process already developed for the frid...

  15. A two dimensional thermal network model for a photovoltaic solar wall

    Energy Technology Data Exchange (ETDEWEB)

    Dehra, Himanshu [1-140 Avenue Windsor, Lachine, Quebec (Canada)

    2009-11-15

    A two dimensional thermal network model is proposed to predict the temperature distribution for a section of photovoltaic solar wall installed in an outdoor room laboratory in Concordia University, Montreal, Canada. The photovoltaic solar wall is constructed with a pair of glass coated photovoltaic modules and a polystyrene filled plywood board as back panel. The active solar ventilation through a photovoltaic solar wall is achieved with an exhaust fan fixed in the outdoor room laboratory. The steady state thermal network nodal equations are developed for conjugate heat exchange and heat transport for a section of a photovoltaic solar wall. The matrix solution procedure is adopted for formulation of conductance and heat source matrices for obtaining numerical solution of one dimensional heat conduction and heat transport equations by performing two dimensional thermal network analyses. The temperature distribution is predicted by the model with measurement data obtained from the section of a photovoltaic solar wall. The effect of conduction heat flow and multi-node radiation heat exchange between composite surfaces is useful for predicting a ventilation rate through a solar ventilation system. (author)

  16. European standards for thermal solar systems and components. The finals

    NARCIS (Netherlands)

    Drück, H.; Heidemann, W.; Müller, H.; Veenstra, A.

    2001-01-01

    In Europe standards for solar collectors, hot water stores and for complete thermal solar systems have been developed during the past six years. This year (2001) these European Standards were established and therefore replaced all corresponding national standards. In the new European standards basic

  17. Solar Thermal AIR Collector Based on New Type Selective Coating

    Directory of Open Access Journals (Sweden)

    Musiy, R.Y.

    2014-01-01

    Full Text Available Based on the best for optical performance and selective coating solar thermal air collector, which operates by solar power on the principle of simultaneous ventilation and heating facilities, is designed. It can be used for vacation homes, museums, wooden churches, warehouses, garages, houses, greenhouses etc.

  18. Thermal stress cycling of GaAs solar cells

    Science.gov (United States)

    Janousek, B. K.; Francis, R. W.; Wendt, J. P.

    1985-01-01

    A thermal cycling experiment was performed on GaAs solar cells to establish the electrical and structural integrity of these cells under the temperature conditions of a simulated low-Earth orbit of 3-year duration. Thirty single junction GaAs cells were obtained and tests were performed to establish the beginning-of-life characteristics of these cells. The tests consisted of cell I-V power output curves, from which were obtained short-circuit current, open circuit voltage, fill factor, and cell efficiency, and optical micrographs, spectral response, and ion microprobe mass analysis (IMMA) depth profiles on both the front surfaces and the front metallic contacts of the cells. Following 5,000 thermal cycles, the performance of the cells was reexamined in addition to any factors which might contribute to performance degradation. It is established that, after 5,000 thermal cycles, the cells retain their power output with no loss of structural integrity or change in physical appearance.

  19. Thermal efficiency of single-pass solar air collector

    Energy Technology Data Exchange (ETDEWEB)

    Ibrahim, Zamry; Ibarahim, Zahari; Yatim, Baharudin [School of Applied Physics, Faculty of Science and Technology, Universiti Kebangsaan Malaysia, 43600 Bangi, Selangor Darul Ehsan (Malaysia); Ruslan, Mohd Hafidz [Solar Energy Research Institute (SERI), Universiti Kebangsaan Malaysia, 43600 Bangi, Selangor Darul Ehsan (Malaysia)

    2013-11-27

    Efficiency of a finned single-pass solar air collector was studied. This paper presents the experimental study to investigate the effect of solar radiation and mass flow rate on efficiency. The fins attached at the back of absorbing plate to improve the thermal efficiency of the system. The results show that the efficiency is increased proportional to solar radiation and mass flow rate. Efficiency of the collector archived steady state when reach to certain value or can be said the maximum performance.

  20. Evaluation of thermal-storage concepts for solar cooling applications

    Science.gov (United States)

    Hughes, P. J.; Morehouse, J. H.; Choi, M. K.; White, N. M.; Scholten, W. B.

    1981-10-01

    Various configuration concepts for utilizing thermal energy storage to improve the thermal and economic performance of solar cooling systems for buildings were analyzed. The storge concepts evaluated provide short-term thermal storge via the bulk containment of water or salt hydrates. The evaluations were made for both residential-size cooling systems (3-ton) and small commercial-size cooling systems (25-ton). The residential analysis considers energy requirements for space heating, space cooling and water heating, while the commercial building analysis is based only on energy requirements for space cooling. The commercial building analysis considered a total of 10 different thermal storage/solar systems, 5 each for absorption and Rankine chiller concepts. The residential analysis considered 4 thermal storage/solar systems, all utilizing an absorption chiller. The trade-offs considered include: cold-side versus hot-side storage, single vs multiple stage storage, and phase-change vs sensible heat storage.

  1. Electrothermal efficiency, temperature and thermal conductivity of ...

    Indian Academy of Sciences (India)

    A study was made to evaluate the electrothermal efficiency of a DC arc plasma torch and temperature and thermal conductivity of plasma jet in the torch. The torch was operated at power levels from 4 to 20 kW in non-transferred arc mode. The effect of nitrogen in combination with argon as plasma gas on the above ...

  2. Electrothermal efficiency, temperature and thermal conductivity of ...

    Indian Academy of Sciences (India)

    Abstract. A study was made to evaluate the electrothermal efficiency of a DC arc plasma torch and temperature and thermal conductivity of plasma jet in the torch. The torch was operated at power levels from 4 to 20 kW in non-transferred arc mode. The effect of nitrogen in combination with argon as plasma gas on the above ...

  3. Solar-thermal experimental projects on the Spanish Plataforma Solar

    Science.gov (United States)

    Grasse, W.

    1981-11-01

    The Plataforma Solar with an area of 1,000,000 sq m is located in Spain at a distance of approximately 50 km from the Mediterranean. In May 1979, nine members of the International Energy Agency (IEA) decided to support the construction of Small Solar Power Systems (SSPS). The countries involved include West Germany, the U.S., Spain, and Italy. The SSPS are to demonstrate the operational feasibility of solar technologies which have been mainly developed in Germany and the U.S. In addition, data are to be obtained regarding the relative competitive position of two different operational concepts for SSPS. The concepts are related to the central receiver system (solar tower) and the distributed collector system. Attention is also given to the Spanish solar power station CESA-1 and the German-Spanish technology program GAST, which is to explore the technological limits of solar-energy systems.

  4. The effects of solar radiation and black body re-radiation on thermal comfort.

    Science.gov (United States)

    Hodder, Simon; Parsons, Ken

    2008-04-01

    When the sun shines on people in enclosed spaces, such as in buildings or vehicles, it directly affects thermal comfort. There is also an indirect effect as surrounding surfaces are heated exposing a person to re-radiation. This laboratory study investigated the effects of long wave re-radiation on thermal comfort, individually and when combined with direct solar radiation. Nine male participants (26.0 +/- 4.7 years) took part in three experimental sessions where they were exposed to radiation from a hot black panel heated to 100 degrees C; direct simulated solar radiation of 600 Wm(-2) and the combined simulated solar radiation and black panel radiation. Exposures were for 30 min, during which subjective responses and mean skin temperatures were recorded. The results showed that, at a surface temperature of 100 degrees C (close to maximum in practice), radiation from the flat black panel provided thermal discomfort but that this was relatively small when compared with the effects of direct solar radiation. It was concluded that re-radiation, from a dashboard in a vehicle, for example, will not have a major direct influence on thermal comfort and that existing models of thermal comfort do not require a specific modification. These results showed that, for the conditions investigated, the addition of re-radiation from internal components has an effect on thermal sensation when combined with direct solar radiation. However, it is not considered that it will be a major factor in a real world situation. This is because, in practice, dashboards are unlikely to maintain very high surface temperatures in vehicles without an unacceptably high air temperature. This study quantifies the contribution of short- and long-wave radiation to thermal comfort. The results will aid vehicle designers to have a better understanding of the complex radiation environment. These include direct radiation from the sun as well as re-radiation from the dashboard and other internal surfaces.

  5. Limits to solar power conversion efficiency with applications to quantum and thermal systems

    Science.gov (United States)

    Byvik, C. E.; Buoncristiani, A. M.; Smith, B. T.

    1983-01-01

    An analytical framework is presented that permits examination of the limit to the efficiency of various solar power conversion devices. Thermodynamic limits to solar power efficiency are determined for both quantum and thermal systems, and the results are applied to a variety of devices currently considered for use in space systems. The power conversion efficiency for single-threshold energy quantum systems receiving unconcentrated air mass zero solar radiation is limited to 31 percent. This limit applies to photovoltaic cells directly converting solar radiation, or indirectly, as in the case of a thermophotovoltaic system. Photoelectrochemical cells rely on an additional chemical reaction at the semiconductor-electrolyte interface, which introduces additional second-law demands and a reduction of the solar conversion efficiency. Photochemical systems exhibit even lower possible efficiencies because of their relatively narrow absorption bands. Solar-powered thermal engines in contact with an ambient reservoir at 300 K and operating at maximum power have a peak conversion efficiency of 64 percent, and this occurs for a thermal reservoir at a temperature of 2900 K. The power conversion efficiency of a solar-powered liquid metal magnetohydrodydnamic generator, a solar-powered steam turbine electric generator, and an alkali metal thermoelectric converter is discussed.

  6. Membrane Material-Based Rigid Solar Array Design and Thermal Simulation for Stratospheric Airships

    Directory of Open Access Journals (Sweden)

    Kangwen Sun

    2014-01-01

    Full Text Available In order to improve effective utilization of rigid solar array used in stratospheric airships here, the flexible connection design and light laminated design were introduced to rigid solar array. Based on the analysis of the design scheme, firstly, the equivalent coefficient of thermal conductivity was calculated by the theoretical formula. Subsequently, the temperature variation characteristics of the solar cell module were accurately modeled and simulated by using Computational Fluid Dynamics (CFD software. Compared to the results of test samples, the solar cell module described here guaranteed effective output as well as good heat insulating ability, effectively improving the feasibility of the stratospheric airship design. In addition, the simulation model can effectively simulate the temperature variation characteristics of the solar cell, which, therefore, provides technical support for the engineering application.

  7. Thermal analysis of solar dryers | Assefa | Zede Journal

    African Journals Online (AJOL)

    Results of the system simulation are presented in graphical fonn suitable for system pe1formance detennination. From the incident solar flux, ambient air temperature and solar collector parameters, the average yearly values of useful energy, the collector outlet air-temperature and air volume flow-rate are also predicted and ...

  8. Thin Thermal-Insulation Blankets for Very High Temperatures

    Science.gov (United States)

    Choi, Michael K.

    2003-01-01

    Thermal-insulation blankets of a proposed type would be exceptionally thin and would endure temperatures up to 2,100 C. These blankets were originally intended to protect components of the NASA Solar Probe spacecraft against radiant heating at its planned closest approach to the Sun (a distance of 4 solar radii). These blankets could also be used on Earth to provide thermal protection in special applications (especially in vacuum chambers) for which conventional thermal-insulation blankets would be too thick or would not perform adequately. A blanket according to the proposal (see figure) would be made of molybdenum, titanium nitride, and carbon- carbon composite mesh, which melt at temperatures of 2,610, 2,930, and 2,130 C, respectively. The emittance of molybdenum is 0.24, while that of titanium nitride is 0.03. Carbon-carbon composite mesh is a thermal insulator. Typically, the blanket would include 0.25-mil (.0.00635-mm)-thick hot-side and cold-side cover layers of molybdenum. Titanium nitride would be vapor-deposited on both surfaces of each cover layer. Between the cover layers there would be 10 inner layers of 0.15-mil (.0.0038-mm)-thick molybdenum with vapor-deposited titanium nitride on both sides of each layer. The thickness of each titanium nitride coat would be about 1,000 A. The cover and inner layers would be interspersed with 0.25-mil (0.00635-mm)-thick layers of carbon-carbon composite mesh. The blanket would have total thickness of 4.75 mils (approximately equal to 0.121 mm) and an areal mass density of 0.7 kilograms per square meter. One could, of course, increase the thermal- insulation capability of the blanket by increasing number of inner layers (thereby unavoidably increasing the total thickness and mass density).

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

    Directory of Open Access Journals (Sweden)

    Smajo Sulejmanovic

    2014-11-01

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

  10. Low temperature thermal-energy storage

    Energy Technology Data Exchange (ETDEWEB)

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

    1979-03-01

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

  11. Thermal energy storage for CSP (Concentrating Solar Power

    Directory of Open Access Journals (Sweden)

    Py Xavier

    2017-01-01

    Full Text Available The major advantage of concentrating solar power before photovoltaic is the possibility to store thermal energy at large scale allowing dispatchability. Then, only CSP solar power plants including thermal storage can be operated 24 h/day using exclusively the solar resource. Nevertheless, due to a too low availability in mined nitrate salts, the actual mature technology of the two tanks molten salts cannot be applied to achieve the expected international share in the power production for 2050. Then alternative storage materials are under studies such as natural rocks and recycled ceramics made from industrial wastes. The present paper is a review of those alternative approaches.

  12. Thermal energy storage for CSP (Concentrating Solar Power)

    Science.gov (United States)

    Py, Xavier; Sadiki, Najim; Olives, Régis; Goetz, Vincent; Falcoz, Quentin

    2017-07-01

    The major advantage of concentrating solar power before photovoltaic is the possibility to store thermal energy at large scale allowing dispatchability. Then, only CSP solar power plants including thermal storage can be operated 24 h/day using exclusively the solar resource. Nevertheless, due to a too low availability in mined nitrate salts, the actual mature technology of the two tanks molten salts cannot be applied to achieve the expected international share in the power production for 2050. Then alternative storage materials are under studies such as natural rocks and recycled ceramics made from industrial wastes. The present paper is a review of those alternative approaches.

  13. Evaluation of ORC processes and their implementation in solar thermal DSG plants

    OpenAIRE

    Degli Esposti, Dalma

    2014-01-01

    Abstract In recent years Direct Steam Generation (DSG) systems using water have been developed as an alternative to state-of-the-art parabolic trough plants with thermal oil. After a comprehensive research, first commercial DSG plants have already been realized. Organic Rankine Cycles (ORC) that have been widely used for electricity production with low-temperature heat (e.g. geothermal energy) are also suited for the implementation in solar thermal power plants. To the knowledge of t...

  14. Quasi-steady state thermal performances of a solar air heater with ...

    African Journals Online (AJOL)

    Quasi-steady state thermal performance of a solar air heater with a combined absorber is studied. The whole energy balance equations related to the system were articulated as a linear system of temperature equations. Solutions to this linear system were assessed from program based on an iterative process. The mean ...

  15. quasi-steady state thermal performances of a solar air heater with ...

    African Journals Online (AJOL)

    2017-01-17

    Jan 17, 2017 ... this linear system were assessed from program based on an iterative process. The mean temperature variation with time and the thermal performance parameters were .... 5 cm each, (6) an adiabatic envelope of protection made of wood. A fraction of the incident solar radiation G0 falling on the collector is ...

  16. Thermal performance of a hot-air solar collector

    Science.gov (United States)

    1978-01-01

    Report contains procedures and results of thermal-performance tests on double-glazed air solar collector. Four types of tests were carried out including thermal-efficiency and stagnation tests, collector time-constant tests to assess effects of transients, and incident-angle modifier tests. Data are presented in tables and as graphs and are discussed and analyzed.

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

    Science.gov (United States)

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

    2016-08-14

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

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

    KAUST Repository

    Zhang, Lianbin

    2016-07-11

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

  19. Potential Use of a Salt Gradient Solar Pond to Store Thermal Energy

    Directory of Open Access Journals (Sweden)

    Daniel Vinícius Silva Veras

    2012-11-01

    Full Text Available Demand for energy sources that allow a sustainable development has stimulated studies on the acquisition of alternative energy, renewable and clean such as hydro, wind, biomass and solar energies. Therefore, the objective in this work was to evaluate the potential of a Salt Gradient Solar Pond (SGSP in order to obtain thermal energy from solar energy. A pilot solar pond with 1,76 m² of surface area and 1 m³ of volume was set up in Itapetinga, Bahia, and temperatures in upper and lower convective layers were monitored between August 20 and November 3, 2008. It was found that the temperature difference between the layers increased from 2°C to 13.2°C, with a medium value of 5.7°C for the period. Considering a 30% efficiency for utilization of stored energy, it would be possible increase by 10°C the temperature of 50 L of chilled milk in a dairy industry, thus demonstrating its potential. In the end of Spring or Summer the temperature difference would be superior. Results demonstrate the potential use of solar ponds by industries and farms in our country, as a renewable and non-polluting alternative, being able to store thermal energy from solar energy.

  20. Solar thermal bowl concepts and economic comparisons for electricity generation

    Energy Technology Data Exchange (ETDEWEB)

    Williams, T.A.; Dirks, J.A.; Brown, D.R.; Antoniak, Z.I.; Allemann, R.T.; Coomes, E.P.; Craig, S.N.; Drost, M.K.; Humphreys, K.K.; Nomura, K.K.

    1988-04-01

    This study is aimed at providing a relative comparison of the thermodynamic and economic performance in electric applications for fixed mirror distributed focus (FMDF) solar thermal concepts which have been studied and developed in the DOE solar thermal program. Following the completion of earlier systems comparison studies in the late 1970's there have been a number of years of progress in solar thermal technology. This progress includes developing new solar components, improving component and system design details, constructing working systems, and collecting operating data on the systems. This study povides an update of the expected performance and cost of the major components, and an overall system energy cost for the FMDDF concepts evaluated. The projections in this study are for the late 1990's and are based on the potential capabilities that might be achieved with further technology development.

  1. Thermal geometry from CFT at finite temperature

    Energy Technology Data Exchange (ETDEWEB)

    Gan, Wen-Cong, E-mail: ganwencong@gmail.com [Department of Physics, Nanchang University, Nanchang 330031 (China); Center for Relativistic Astrophysics and High Energy Physics, Nanchang University, Nanchang 330031 (China); Shu, Fu-Wen, E-mail: shufuwen@ncu.edu.cn [Department of Physics, Nanchang University, Nanchang 330031 (China); Center for Relativistic Astrophysics and High Energy Physics, Nanchang University, Nanchang 330031 (China); Wu, Meng-He, E-mail: menghewu.physik@gmail.com [Department of Physics, Nanchang University, Nanchang 330031 (China); Center for Relativistic Astrophysics and High Energy Physics, Nanchang University, Nanchang 330031 (China)

    2016-09-10

    We present how the thermal geometry emerges from CFT at finite temperature by using the truncated entanglement renormalization network, the cMERA. For the case of 2d CFT, the reduced geometry is the BTZ black hole or the thermal AdS as expectation. In order to determine which spacetimes prefer to form, we propose a cMERA description of the Hawking–Page phase transition. Our proposal is in agreement with the picture of the recent proposed surface/state correspondence.

  2. Thermal geometry from CFT at finite temperature

    Directory of Open Access Journals (Sweden)

    Wen-Cong Gan

    2016-09-01

    Full Text Available We present how the thermal geometry emerges from CFT at finite temperature by using the truncated entanglement renormalization network, the cMERA. For the case of 2d CFT, the reduced geometry is the BTZ black hole or the thermal AdS as expectation. In order to determine which spacetimes prefer to form, we propose a cMERA description of the Hawking–Page phase transition. Our proposal is in agreement with the picture of the recent proposed surface/state correspondence.

  3. Solar cooling - state of the art of solar thermally driven heat pumps for cooling

    OpenAIRE

    Jakob, Uli

    2013-01-01

    Part of: Thermally driven heat pumps for heating and cooling. – Ed.: Annett Kühn – Berlin: Universitätsverlag der TU Berlin, 2013 ISBN 978-3-7983-2686-6 (print) ISBN 978-3-7983-2596-8 (online) urn:nbn:de:kobv:83-opus4-39458 [http://nbn-resolving.de/urn:nbn:de:kobv:83-opus4-39458] An attractive alternative to conventional electricity driven cooling systems is solar cooling, which combines thermally driven heat pumps/chillers with solar thermal collectors. Solar co...

  4. Thermal effects investigation on electrical properties of silicon solar cells treated by laser irradiation

    Directory of Open Access Journals (Sweden)

    Ali Pourakbar Saffar

    2014-12-01

    Full Text Available In this paper, we were investigated electrical properties of monocrystalline and polycrystalline silicon solar cells due to laser irradiation with 650 nm wavelength in two states, proximate irradiation and via optics setup. Thermal effect on the cell surface due to laser irradiation was investigated on electrical properties too. Electrical parameters investigation of solar cells illustrates cell excitement via laser irradiation and efficiency decreases due to cell surface temperature increase. Monocrystalline parameters change with uniform shape due to thermal effect and laser irradiation toward polycrystalline cells.

  5. Thermal storage/discharge performances of Cu-Si alloy for solar thermochemical process

    Science.gov (United States)

    Gokon, Nobuyuki; Yamaguchi, Tomoya; Cho, Hyun-seok; Bellan, Selvan; Hatamachi, Tsuyoshi; Kodama, Tatsuya

    2017-06-01

    The present authors (Niigata University, Japan) have developed a tubular reactor system using novel "double-walled" reactor/receiver tubes with carbonate molten-salt thermal storage as a phase change material (PCM) for solar reforming of natural gas and with Al-Si alloy thermal storage as a PCM for solar air receiver to produce high-temperature air. For both of the cases, the high heat capacity and large latent heat (heat of solidification) of the PCM phase circumvents the rapid temperature change of the reactor/receiver tubes at high temperatures under variable and uncontinuous characteristics of solar radiation. In this study, we examined cyclic properties of thermal storage/discharge for Cu-Si alloy in air stream in order to evaluate a potentiality of Cu-Si alloy as a PCM thermal storage material. Temperature-increasing performances of Cu-Si alloy are measured during thermal storage (or heat-charge) mode and during cooling (or heat-discharge) mode. A oxidation state of the Cu-Si alloy after the cyclic reaction was evaluated by using electron probe micro analyzer (EPMA).

  6. 5-Megawatt solar-thermal test facility: environmental assessment

    Energy Technology Data Exchange (ETDEWEB)

    None

    1976-01-30

    An Environmental Assessment of the 5 Megawatt Solar Thermal Test Facility (STTF) is presented. The STTF is located at Albuquerque, New Mexico. The facility will have the capability for testing scale models of major subsystems comprising a solar thermal electrical power plant. The STTF capabilities will include testing a solar energy collector subsystem comprised of heliostat arrays, a receiver subsystem which consists of a boiler/superheater in which a working fluid is heated, and a thermal storage subsystem which includes tanks of high heat capacity material which stores thermal energy for subsequent use. The STTF will include a 200-foot receiver tower on which experimental receivers will be mounted. The Environmental Assessment describes the proposed STTF, its anticipated benefits, and the environment affected. It also evaluates the potential environmental impacts associated with STTF construction and operation.

  7. Heat engine requirements for advanced solar thermal power systems

    Science.gov (United States)

    Jaffe, L. D.; Pham, H. Q.

    1981-01-01

    Requirements and constraints are established for power conversion subsystems, including heat engine, alternator and auxiliaries, of dish concentrator solar thermal power systems. In order to be competitive with conventional power systems, it is argued that the heat engine should be of less than 40 kW rated output, in a subsystem with an efficiency of at least 40% at rated output and at least 37% at half power. An interval between major overhauls of 50,000 hours is also desirable, along with minor maintenance and lubrication not more than four times a year requiring no more than one man-hour each time, and optimal reliability. Also found to be important are the capability for hybrid operation using heat from a solar receiver, fuel-fired combustor or both simultaneously, operation at any attitude, stability to transients in input power and output loading, operation at ambient temperatures from -30 to 50 C, and compatibility with environmental and safety requirements. Cost targets include a price of $180/kWe, and operation, maintenance and replacement costs averaging $0.001/kWh for 30 years of operation.

  8. Whistler-cyclotron spontaneous fluctuations as a proxy to identify thermal and non-thermal electrons in the solar wind

    Science.gov (United States)

    Moya, P. S.; Vinas, A. F.; Navarro, R.; Araneda, J. A.

    2014-12-01

    Observed electron velocity distributions in the solar wind exhibit a variety of non-thermal features which deviate from thermal equilibrium, in the form of temperature anisotropies, suprathermal tails, and field aligned beams. The state close to thermal equilibrium and its departure from it provides a source for spontaneous emissions of electromagnetic fluctuations as for example the whistler cyclotron waves at electron scales. Here we present a comparative analysis of these fluctuations based upon anisotropic plasma modeled with thermal and non-thermal particle distributions. The analysis presented here considers the second-order theory of fluctuations and the dispersion relation of weakly transverse fluctuations, with wave vectors parallel to the uniform background magnetic field, in a finite temperature isotropic thermal bi-Maxwellian and non-thermal Tsallis-kappa-like magnetized electron-proton plasma. Dispersion analysis and stability thresholds are derived for these non-thermal distributions and compared with similar results obtained from PIC simulations using plasma and field parameters relevant to the solar wind environments. Our results indicate that there is a strong dependence between the shape of the velocity distribution function and the topological regions in the frequency-wave number plane in which the spontaneous fluctuations emerge. In the case of non-thermal plasmas there is an enhancement of the fluctuations level due to the effective higher-temperature effects and the excess of suprathermal particles. This feature may be used proxy to identify the nature of electron populations in space plasmas when high resolution particle instruments are not available.

  9. Case study of skin temperature and thermal perception in a hot outdoor environment.

    Science.gov (United States)

    Pantavou, Katerina; Chatzi, Evriklia; Theoharatos, George

    2014-08-01

    Focusing on the understanding and the estimation of the biometeorological conditions during summer in outdoor places, a field study was conducted in July 2010 in Athens, Greece over 6 days at three different sites: Syntagma Square, Ermou Street and Flisvos coast. Thermo-physiological measurements of five subjects were carried out from morning to evening for each site, simultaneously with meteorological measurements and subjective assessments of thermal sensation reported by questionnaires. The thermo-physiological variables measured were skin temperature, heat flux and metabolic heat production, while meteorological measurements included air temperature, relative humidity, wind speed, globe temperature, ground surface temperature and global radiation. The possible relation of skin temperature with the meteorological parameters was examined. Theoretical values of mean skin temperature and mean radiant temperature were estimated applying the MENEX model and were compared with the measured values. Two biometeorological indices, thermal sensation (TS) and heat load (HL)-were calculated in order to compare the predicted thermal sensation with the actual thermal vote. The theoretically estimated values of skin temperature were underestimated in relation to the measured values, while the theoretical model of mean radiant temperature was more sensitive to variations of solar radiation compared to the experimental values. TS index underestimated the thermal sensation of the five subjects when their thermal vote was 'hot' or 'very hot' and overestimated thermal sensation in the case of 'neutral'. The HL index predicted with greater accuracy thermal sensation tending to overestimate the thermal sensation of the subjects.

  10. Residential Solar-Based Seasonal Thermal Storage Systems in Cold Climates: Building Envelope and Thermal Storage

    Directory of Open Access Journals (Sweden)

    Alexandre Hugo

    2012-10-01

    Full Text Available The reduction of electricity use for heating and domestic hot water in cold climates can be achieved by: (1 reducing the heating loads through the improvement of the thermal performance of house envelopes, and (2 using solar energy through a residential solar-based thermal storage system. First, this paper presents the life cycle energy and cost analysis of a typical one-storey detached house, located in Montreal, Canada. Simulation of annual energy use is performed using the TRNSYS software. Second, several design alternatives with improved thermal resistance for walls, ceiling and windows, increased overall air tightness, and increased window-to-wall ratio of South facing windows are evaluated with respect to the life cycle energy use, life cycle emissions and life cycle cost. The solution that minimizes the energy demand is chosen as a reference house for the study of long-term thermal storage. Third, the computer simulation of a solar heating system with solar thermal collectors and long-term thermal storage capacity is presented. Finally, the life cycle cost and life cycle energy use of the solar combisystem are estimated for flat-plate solar collectors and evacuated tube solar collectors, respectively, for the economic and climatic conditions of this study.

  11. Solar radiation and thermal performance of solar collectors for Denmark

    DEFF Research Database (Denmark)

    Dragsted, Janne; Furbo, Simon

    This report describes the part of the EUDP project “EUDP 11-l, Solar Resource Assessment in Denmark”, which is carried out at Department of Civil Engineering, Technical University of Denmark.......This report describes the part of the EUDP project “EUDP 11-l, Solar Resource Assessment in Denmark”, which is carried out at Department of Civil Engineering, Technical University of Denmark....

  12. Solar dryer with thermal storage and biomass-backup heater

    Energy Technology Data Exchange (ETDEWEB)

    Madhlopa, A. [Department of Physics and Biochemical Sciences, Malawi Polytechnic, P/Bag 303, Blantyre 3 (Malawi); Ngwalo, G. [Department of Mechanical Engineering, Malawi Polytechnic, P/Bag 303, Blantyre 3 (Malawi)

    2007-04-15

    An indirect type natural convection solar dryer with integrated collector-storage solar and biomass-backup heaters has been designed, constructed and evaluated. The major components of the dryer are biomass burner (with a rectangular duct and flue gas chimney), collector-storage thermal mass and drying chamber (with a conventional solar chimney). The thermal mass was placed in the top part of the biomass burner enclosure. The dryer was fabricated using simple materials, tools and skills, and it was tested in three modes of operation (solar, biomass and solar-biomass) by drying twelve batches of fresh pineapple (Ananas comosus), with each batch weighing about 20 kg. Meteorological conditions were monitored during the dehydration process. Moisture and vitamin C contents were determined in both fresh and dried samples. Results show that the thermal mass was capable of storing part of the absorbed solar energy and heat from the burner. It was possible to dry a batch of pineapples using solar energy only on clear days. Drying proceeded successfully even under unfavorable weather conditions in the solar-biomass mode of operation. In this operational mode, the dryer reduced the moisture content of pineapple slices from about 669 to 11% (db) and yielded a nutritious dried product. The average values of the final-day moisture-pickup efficiency were 15%, 11% and 13% in the solar, biomass and solar-biomass modes of operation respectively. It appears that the solar dryer is suitable for preservation of pineapples and other fresh foods. Further improvements to the system design are suggested. (author)

  13. Thermal phase diagram of acetamide-benzoic acid and benzoic acid-phthalimide binary systems for solar thermal applications

    Energy Technology Data Exchange (ETDEWEB)

    Kumar, Rohitash, E-mail: dootrohit1976@gmail.com [Defence Laboratory Jodhpur, Rajasthan, India 342011, +91-2912567520 (India); Department of Physics & Center for Solar Energy, Indian Institute of Technology Jodhpur, Rajasthan, India 342011, +91-291-2449045 (India); Kumar, Ravindra [Defence Laboratory Jodhpur, Rajasthan, India 342011, +91-2912567520 (India); Dixit, Ambesh, E-mail: ambesh@iitj.ac.in [Department of Physics & Center for Solar Energy, Indian Institute of Technology Jodhpur, Rajasthan, India 342011, +91-291-2449045 (India)

    2016-05-06

    Thermal properties of Acetamide (AM) – Benzoic acid (BA) and Benzoic acid (BA) – Phthalimide (PM) binary eutectic systems are theoretically calculated using thermodynamic principles. We found that the binary systems of AM-BA at 67.6 : 32.4 molar ratio, BA-PM at 89.7 : 10.3 molar ratio form eutectic mixtures with melting temperatures ~ 54.5 °C and 114.3 °C respectively. Calculated latent heat of fusion for these eutectic mixtures are 191 kJ/kg and 146.5 kJ/kg respectively. These melting temperatures and heat of fusions of these eutectic mixtures make them suitable for thermal energy storage applications in solar water heating and solar cooking systems.

  14. Metal glass vacuum tube solar collectors are approaching lower-medium temperature heat application.

    Science.gov (United States)

    Jiang, Xinian

    2010-04-26

    Solar thermal collectors are widely used worldwide mainly for hot water preparation at a low temperature (less than 80?C). Applications including many industrial processes and central air conditioning with absorption chillers, instead require lower-medium temperature heat (between 90 degrees C and 150 degrees C) to be driven when using solar thermal energy. The metal absorber glass vacuum tube collectors (MGVT) are developed for this type of applications. Current state-of-art and possible future technology development of MGVT are presented.

  15. Thermal fuse for high-temperature batteries

    Science.gov (United States)

    Jungst, Rudolph G.; Armijo, James R.; Frear, Darrel R.

    2000-01-01

    A thermal fuse, preferably for a high-temperature battery, comprising leads and a body therebetween having a melting point between approximately 400.degree. C. and 500.degree. C. The body is preferably an alloy of Ag--Mg, Ag--Sb, Al--Ge, Au--In, Bi--Te, Cd--Sb, Cu--Mg, In--Sb, Mg--Pb, Pb--Pd, Sb--Zn, Sn--Te, or Mg--Al.

  16. Experimental investigation of a nanofluid absorber employed in a low-profile, concentrated solar thermal collector

    Science.gov (United States)

    Li, Qiyuan; Zheng, Cheng; Mesgari, Sara; Hewakuruppu, Yasitha L.; Hjerrild, Natasha; Crisostomo, Felipe; Morrison, Karl; Woffenden, Albert; Rosengarten, Gary; Scott, Jason A.; Taylor, Robert A.

    2015-12-01

    Recent studies [1-3] have demonstrated that nanotechnology, in the form of nanoparticles suspended in water and organic liquids, can be employed to enhance solar collection via direct volumetric absorbers. However, current nanofluid solar collector experimental studies are either relevant to low-temperature flat plate solar collectors (100 °C) indoor laboratory-scale concentrating solar collectors [1, 5]. Moreover, many of these studies involve in thermal properties of nanofluid (such as thermal conductivity) enhancement in solar collectors by using conventional selective coated steel/copper tube receivers [6], and no full-scale concentrating collector has been tested at outdoor condition by employing nanofluid absorber [2, 6]. Thus, there is a need of experimental researches to evaluate the exact performance of full-scale concentrating solar collector by employing nanofluids absorber at outdoor condition. As reported previously [7-9], a low profile (solar thermal concentrating collector was designed and analysed which can potentially supply thermal energy in the 100-250 °C range (an application currently met by gas and electricity). The present study focuses on the design and experimental investigation of a nanofluid absorber employed in this newly designed collector. The nanofluid absorber consists of glass tubes used to contain chemically functionalized multi-walled carbon nanotubes (MWCNTs) dispersed in DI water. MWCNTs (average diameter of 6-13 nm and average length of 2.5-20 μm) were functionalized by potassium persulfate as an oxidant. The nanofluids were prepared with a MCWNT concentration of 50 +/- 0.1 mg/L to form a balance between solar absorption depth and viscosity (e.g. pumping power). Moreover, experimentally comparison of the thermal efficiency between two receivers (a black chrome-coated copper tube versus a MWCNT nanofluid contained within a glass tubetube) is investigated. Thermal experimentation reveals that while the collector efficiency

  17. Tehachapi solar thermal system first annual report

    Energy Technology Data Exchange (ETDEWEB)

    Rosenthal, A. [Southwest Technology Development Inst., Las Cruces, NM (US)

    1993-05-01

    The staff of the Southwest Technology Development Institute (SWTDI), in conjunction with the staff of Industrial Solar Technology (IST), have analyzed the performance, operation, and maintenance of a large solar process heat system in use at the 5,000 inmate California Correctional Institution (CCI) in Tehachapi, CA. This report summarizes the key design features of the solar plant, its construction and maintenance histories through the end of 1991, and the performance data collected at the plant by a dedicated on-site data acquisition system (DAS).

  18. Recent experience with large solar thermal systems in The Netherlands

    Energy Technology Data Exchange (ETDEWEB)

    Bokhoven, T.P.; Dam, J. Van; Kratz, P. [ZEN-International bv, Gouda (Netherlands)

    2001-07-01

    Since 1995, two large solar thermal systems (1200 and 2400 m{sup 2}) have been realised in The Netherlands for industrial purposes. It is expected that large solar systems will be used more often in the coming years. For that reason and for the benefit of successful solar projects, important practical experience with these large systems is reported. In 1995/1996, a system was constructed in Lisse for the purpose of agricultural drying and conditioning, consisting of a 1200-m{sup 2} (high performance) flat-plate collector array and a 1000-m{sup 3} water storage tank. The tank has been constructed as the foundation of a warehouse building and is situated below groundwater level. The combination of these two conditions, together with the other storage parameters, has given grounds for many extra design considerations compared to other underground storage units. Special details had to be designed, for these specific conditions, concerning leakages (in/out of the tank), anti-floating measures and underwater insulation which is stable at high temperatures. The lessons learned in this project can be of value for those considering the construction of this kind of underground storage unit. In 1996/1997, a 2400-m{sup 2} system was realised in Breda at a confectionery factory (van Melle), in which the drain-back concept was used on such a scale for the first time. The various design characteristics for drain-back systems, as were already known from two decades of usage in small domestic hot water systems, were upscaled to a 'super drain-back' system. The scale of the project further emphasised the advantages of this concept in cost (both operational and investment), performance and safety. However, the size of the system also brought some unexpected side effects which should be taken into account in future designs. (Author)

  19. Solar thermal power systems. Annual technical progress report, FY 1979

    Energy Technology Data Exchange (ETDEWEB)

    Braun, Gerald W.

    1980-06-01

    The Solar Thermal Power Systems Program is the key element in the national effort to establish solar thermal conversion technologies within the major sectors of the national energy market. It provides for the development of concentrating mirror/lens heat collection and conversion technologies for both central and dispersed receiver applications to produce electricity, provide heat at its point of use in industrial processes, provide heat and electricity in combination for industrial, commercial, and residential needs, and ultimately, drive processes for production of liquid and gaseous fuels. This report is the second Annual Technical Progress Report for the Solar Thermal Power Systems Program and is structured according to the organization of the Solar Thermal Power Systems Program on September 30, 1979. Emphasis is on the technical progress of the projects rather than on activities and individual contractor efforts. Each project description indicates its place in the Solar Thermal Power Systems Program, a brief history, the significant achievements and real progress during FY 1979, also future project activities as well as anticipated significant achievements are forecast. (WHK)

  20. Temperature and Solar Radiation Effects on Photovoltaic Panel Power

    OpenAIRE

    Karafil, Akif; Ozbay, Harun; Kesler, Metin

    2016-01-01

    Solar energy is converted to electrical energy directly by semi-conductors materials used in Photovoltaic (PV) panels. Although, there has been great advancements in semi-conductor material technology in recent years panel efficiency is very lower. There are many factors affecting the panel efficiency such as tilt angle, shading, dust, solar radiation level, temperature and wiring losses. Among these factors, solar radiation level and temperature are more prominent. The solar radiation level ...

  1. Materials compatibility issues related to thermal energy storage for a space solar dynamic power system

    Science.gov (United States)

    Faget, N. M.

    1986-01-01

    Attention is given to results obtained to date in developmental investigations of a thermal energy storage (TES) system for the projected NASA Space Station's solar dynamic power system; these tests have concentrated on issues related to materials compatibility for phase change materials (PCMs) and their containment vessels' materials. The five PCMs tested have melting temperatures that correspond to the operating temperatures of either the Brayton or Rankine heat engines, which were independently chosen for their high energy densities.

  2. Thermal Testing Methods for Solar Dryers

    DEFF Research Database (Denmark)

    Singh, Shobhana

    2017-01-01

    Solar food drying is a complex heat and mass transfer phenomena which depend on a number of drying process-dependent parameters such as operating conditions and characteristics of the food product to be dried. The variation in these parameters significantly affects the overall performance...... for the most common designs of solar dryers and the related practices used in the measurement, evaluation, and description of overall performance, including a variety of food product dried in scientific investigations....

  3. Residential Solar-Based Seasonal Thermal Storage Systems in Cold Climates: Building Envelope and Thermal Storage

    OpenAIRE

    Alexandre Hugo; Radu Zmeureanu

    2012-01-01

    The reduction of electricity use for heating and domestic hot water in cold climates can be achieved by: (1) reducing the heating loads through the improvement of the thermal performance of house envelopes, and (2) using solar energy through a residential solar-based thermal storage system. First, this paper presents the life cycle energy and cost analysis of a typical one-storey detached house, located in Montreal, Canada. Simulation of annual energy use is performed using the TRNSYS softwar...

  4. Thermal Storage Capacity and Night Ventilation Performance of a Solar Chimney Combined with Different PCMs

    Directory of Open Access Journals (Sweden)

    Jun Lu

    2017-01-01

    Full Text Available Thermal storage capacity and airflow rate of a solar chimney combined with different PCMs are numerically studied during nighttime. PCMs with phase change temperatures of 38°C, 44°C, 50°C, and 63°C are selected in this numerical study. Results show that the maximum average ventilation rate of 610 kg/m2 and maximum thermal storage of 4750 kJ/m2 are achieved at the phase change temperature of 38°C. However, for phase change temperature of 63°C, night ventilation does not occur under the identical conditions. The findings reveal that a lower phase change temperature can increase the chargeability (and therefore the dischargeability of a solar chimney, since a higher phase change temperature demands higher solar radiation intensity and longer charging time for a solar chimney. For PCM with a phase change temperature of 44°C, most of the heat stored in PCM is lost to ambient through glass cover by radiation and only a small portion is used for heating the air within air channel.

  5. Advanced latent heat of fusion thermal energy storage for solar power systems

    Science.gov (United States)

    Phillips, W. M.; Stearns, J. W.

    1985-01-01

    The use of solar thermal power systems coupled with thermal energy storage (TES) is being studied for both terrestrial and space applications. In the case of terrestrial applications, it was found that one or two hours of TES could shift the insolation peak (solar noon) to coincide with user peak loads. The use of a phase change material (PCM) is attractive because of the higher energy storage density which can be achieved. However, the use of PCM has also certain disadvantages which must be addressed. Proof of concept testing was undertaken to evaluate corrosive effects and thermal ratcheting effects in a slurry system. It is concluded that the considered alkali metal/alkali salt slurry approach to TES appears to be very viable, taking into account an elimination of thermal ratcheting in storage systems and the reduction of corrosive effects. The approach appears to be useful for an employment involving temperatures applicable to Brayton or Stirling cycles.

  6. Effect of openings collectors and solar irradiance on the thermal efficiency of flat plate-finned collector for indirect-type passive solar dryer

    Science.gov (United States)

    Batubara, Fatimah; Dina, Sari Farah; Klaudia Kathryn Y., M.; Turmuzi, M.; Siregar, Fitri; Panjaitan, Nora

    2017-06-01

    Research on the effect of openings solar collector and solar irradiance to thermal efficiency has been done. Solar collector by flat plate-finned type consists of 3 ply insulator namely wood, Styrofoam and Rockwool with thickness respectively are 10 mm, 25 mm and 50 mm. Absorber plate made of aluminum sheet with thickness of 0.30 mm, painted by black-doff. Installation of 19 units fins (length x height x thickness: 1000x20x10 mm) on the collector will increase surface area of absorber so it can receive much more solar energy. The solar collector cover is made of glass (thickness of 5 mm). During the research, the solar irradiance and temperature of collector are measured and recorded every five minutes. Temperature measurement performed on the surface of the absorber plate, inside of collector, surface cover and the outer side insulator (plywood). This data is used to calculate the heat loss due to conduction, convection and radiation on the collector. Openings of collectors vary as follows: 100%, 75%, 15% and 0% (total enclosed). The data collecting was conducted from 09.00 am to 17.00 pm and triplicates. The collector thermal efficiency calculated based on the ratio of the amount of heat received to the solar irradiance absorbed. The results show that each of openings solar collector has different solar irradiance (because it was done on a different day) which is in units of W/m2: 390 (100% open), 376 (75% open), 429 (15% open), and 359 (totally enclosed). The highest thermal efficiency is in openings variation of 15% opened. These results indicate that the efficiency of the collector is influenced by the solar irradiance received by the collector and the temperature on the collector plate. The highest thermal efficiency is in variation of openings 15%. These indicate that the efficiency of the collector was influenced by solar irradiance received by the collector and openings of the collector plate.

  7. Thermal performance of evacuated tube heat pipe solar collector

    Science.gov (United States)

    Putra, Nandy; Kristian, M. R.; David, R.; Haliansyah, K.; Ariantara, Bambang

    2016-06-01

    The high fossil energy consumption not only causes the scarcity of energy but also raises problems of global warming. Increasing needs of fossil fuel could be reduced through the utilization of solar energy by using solar collectors. Indonesia has the abundant potential for solar energy, but non-renewable energy sources still dominate energy consumption. With heat pipe as passive heat transfer device, evacuated tube solar collector is expected to heat up water for industrial and home usage without external power supply needed to circulate water inside the solar collector. This research was conducted to determine the performance of heat pipe-based evacuated tube solar collector as solar water heater experimentally. The experiments were carried out using stainless steel screen mesh as a wick material, and water and Al2O3-water 0.1% nanofluid as working fluid, and applying inclination angles of 0°, 15°, 30°, and 45°. To analyze the heat absorbed and transferred by the prototype, water at 30°C was circulated through the condenser. A 150 Watt halogen lamp was used as sun simulator, and the prototype was covered by an insulation box to obtain a steady state condition with a minimum affection of ambient changes. Experimental results show that the usage of Al2O3-water 0.1% nanofluid at 30° inclination angle provides the highest thermal performance, which gives efficiency as high as 0.196 and thermal resistance as low as 5.32 °C/W. The use of nanofluid as working fluid enhances thermal performance due to high thermal conductivity of the working fluid. The increase of the inclination angle plays a role in the drainage of the condensate to the evaporator that leads to higher thermal performance until the optimal inclination angle is reached.

  8. Barriers to the Diffusion of Solar Thermal Technologies

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2006-07-01

    Despite its considerable potential in household, domestic and industry sectors, the possible contribution of solar heat is often neglected in many academic and institutional energy projections and scenarios. This is best explained by the frequent failure to distinguish heat and work as two different forms of energy transfers. As a result, policy makers in many countries or States have tended to pay lesser attention to solar thermal technologies than to other renewable energy technologies.

  9. High Performance Flat Plate Solar Thermal Collector Evaluation

    Energy Technology Data Exchange (ETDEWEB)

    Rockenbaugh, Caleb [National Renewable Energy Lab. (NREL), Golden, CO (United States); Dean, Jesse [National Renewable Energy Lab. (NREL), Golden, CO (United States); Lovullo, David [National Renewable Energy Lab. (NREL), Golden, CO (United States); Lisell, Lars [National Renewable Energy Lab. (NREL), Golden, CO (United States); Barker, Greg [National Renewable Energy Lab. (NREL), Golden, CO (United States); Hanckock, Ed [National Renewable Energy Lab. (NREL), Golden, CO (United States); Norton, Paul [National Renewable Energy Lab. (NREL), Golden, CO (United States)

    2016-09-01

    This report was prepared for the General Services Administration by the National Renewable Energy Laboratory. The Honeycomb Solar Thermal Collector (HSTC) is a flat plate solar thermal collector that shows promising high efficiencies over a wide range of climate zones. The technical objectives of this study are to: 1) verify collector performance, 2) compare that performance to other market-available collectors, 3) verify overheat protection, and 4) analyze the economic performance of the HSTC both at the demonstration sites and across a matrix of climate zones and utility markets.

  10. Experimental Investigation on a Thermal Model for a Basin Solar Still with an External Reflector

    Directory of Open Access Journals (Sweden)

    Masoud Afrand

    2016-12-01

    Full Text Available In this study, a thermal model for estimating the efficiency of a basin solar still with an external reflector was introduced using the energy balance equations of different parts of the solar still. Then, in order to verify the precision and accuracy of this model, a basin solar still with an external reflector was constructed and some experiments were performed. The hourly temperature values for different places of the still and amount of distilled water were calculated using the thermal model and compared with experimental measurements. Comparisons show that the thermal model of the still is in good agreement with the experimental results. Therefore, it can be concluded that the introduced thermal model can be used reliably to estimate the amount of distilled water and efficiency of the basin solar still with an external reflector. Results also revealed that the efficiency of the solar still is low in the early hours, while it was enhanced 44% in the afternoon. Furthermore, it was concluded that the accumulated distilled water is 4600 mL/day and 4300 mL/day for theoretical and experimental examinations, respectively.

  11. The transient thermal response of a tubular solar collector

    Science.gov (United States)

    Lansing, F. L.

    1976-01-01

    A special analytical solution is provided for the timewise response of the circulating fluid temperatures when a sudden step change of the input solar radiation is imposed and remains constant thereafter. An example which demonstrates the transient temperatures at the exit section of a single collector with two different flow patterns is presented. This study is used to supplement some numerical solutions to provide a fairly complete coverage for this type of solar collector.

  12. Decentralised cooling of electronic equipment using the thermal conversion of solar energy

    Energy Technology Data Exchange (ETDEWEB)

    Rodriguez, P.; Lecuona, A.; Venegas, M.; Sardina, M.; Rodriguez, M.C.; Lopez, S. [Departamento de Ingenieria Termica y de Fluidos, Universidad Carlos III de Madrid (UC3M), Madrid, (SP); Izquierdo, M. [Instituto de Ciencias de la Construccion Eduardo Torroja (CSIC), Madrid (SP)

    2002-07-01

    In this work, the application of solar energy in electronic equipment cooling is evaluated. The whole facility including thermal load, an absorption cooling machine, a gas driven boiler and a thermal solar system composed by 50 m2 of flat collectors, heat exchanger, 2 m3 storage tank and pumps, is simulated. Real environmental data corresponding to several extremely hot summer days in Madrid including solar radiation, ambient temperature and humidity and wind velocity and direction, were measured and applied in the system performance evaluation. For model validation, a 50 m2 flat thermal solar panels system in the UC3M, were monitored with temperature and water flow sensors. The absorption cooling machine was also monitored. Experimental data were taken at 2 seconds acquisition rate, saving averaged values over 10 minutes. Thermal environmental and electrical load daily fluctuation was also simulated using a communication wireless real equipment specifications. With the assistance of simulation, the effect of storage tank dimensioning on the system operating time is analyzed. Finally, a comparison with a conventional mechanical compressor driven cooling machine is performed. The environmental impact reduction is also computed and results are shown and discussed.

  13. Thermal Performance of a Large Low Flow Solar Heating System with a Highly Thermally Stratified Tank

    DEFF Research Database (Denmark)

    Furbo, Simon; Vejen, Niels Kristian; Shah, Louise Jivan

    2005-01-01

    is performing well in spite of the fact that the solar collectors are far from being orientated optimally. The utilization of the solar radiation on the collectors is higher, 46% in the second year of operation, than for any other system earlier investigated in Denmark, 16%-34%. The reason for the good thermal...... performance and for the excellent utilization of the solar radiation is the high hot-water consumption and the good system design making use of external heat exchangers and stratification inlet pipes.......In year 2000 a 336 m² solar domestic hot water system was built in Sundparken, Elsinore, Denmark. The solar heating system is a low flow system with a 10000 l hot-water tank. Due to the orientation of the buildings half of the solar collectors are facing east, half of the solar collectors...

  14. Real-Time System Application in Solar Thermal Plants

    Energy Technology Data Exchange (ETDEWEB)

    Gonzalez, J.; Yebra, L. J.; Valverde, A.; Berenguel, M.; Peralta, M.

    2006-07-01

    Activities performed in solar plants usually generate solar radiation concentrations. Those concentrations can reach very high temperatures, so errors calculating the positions where the concentrations must aim or exceeding the time when those positions must be supplied, can cause damage in people or in radiated components. The designs of certain applications in solar plants must be done using Real-Time System perspective to meet time and safety requirements. In the article we describe how we are implementing an application used in a solar plant to meet time and safety requirements. (Author)

  15. From Molecular Electronics to Solar Thermal Energy Storage

    DEFF Research Database (Denmark)

    Olsen, Stine Tetzschner

    The Sun's signicant resource potential provides a solution for the world's increasing energy demand in a sustainable and responsible manner. However, the intrinsic property of the on-o cycles of the solar irradiation, i.e. daynight, sunny-cloudy, and summer-winter, constitutes a signicant challenge...... for the utilization of solar energy. An eective technology for storing the solar energy is required. This thesis focuses on solar thermal energy storage in molecules, since it oers a very compact and eective storage method. The rst chapter after the introduction of the thesis, chapter two, introduces the fundamental...... properties of the molecule, i.e. the electronic behaviour of the molecule in dierent environments, which is a key property for investigations of solar energy storage. The main focus of the research is on the electron transport in the Coulomb blockade regime. The third chapter goes into the challenge...

  16. Solar Power for Near Sun, High-Temperature Missions

    Science.gov (United States)

    Landis, Geoffrey A.

    2008-01-01

    Existing solar cells lose performance at the high temperatures encountered in Mercury orbit and inward toward the sun. For future missions designed to probe environments close to the sun, it is desirable to develop array technologies for high temperature and high light intensity. Approaches to solar array design for near-sun missions include modifying the terms governing temperature of the cell and the efficiency at elevated temperature, or use of techniques to reduce the incident solar energy to limit operating temperature. An additional problem is found in missions that involve a range of intensities, such as the Solar Probe + mission, which ranges from a starting distance of 1 AU from the sun to a minimum distance of 9.5 solar radii, or 0.044 AU. During the mission, the solar intensity ranges from one to about 500 times AM0. This requires a power system to operate over nearly three orders of magnitude of incident intensity.

  17. Model predictive control of a solar-thermal reactor

    Science.gov (United States)

    Saade Saade, Maria Elizabeth

    Solar-thermal reactors represent a promising alternative to fossil fuels because they can harvest solar energy and transform it into storable and transportable fuels. The operation of solar-thermal reactors is restricted by the available sunlight and its inherently transient behavior, which affects the performance of the reactors and limits their efficiency. Before solar-thermal reactors can become commercially viable, they need to be able to maintain a continuous high-performance operation, even in the presence of passing clouds. A well-designed control system can preserve product quality and maintain stable product compositions, resulting in a more efficient and cost-effective operation, which can ultimately lead to scale-up and commercialization of solar thermochemical technologies. In this work, we propose a model predictive control (MPC) system for a solar-thermal reactor for the steam-gasification of biomass. The proposed controller aims at rejecting the disturbances in solar irradiation caused by the presence of clouds. A first-principles dynamic model of the process was developed. The model was used to study the dynamic responses of the process variables and to identify a linear time-invariant model used in the MPC algorithm. To provide an estimation of the disturbances for the control algorithm, a one-minute-ahead direct normal irradiance (DNI) predictor was developed. The proposed predictor utilizes information obtained through the analysis of sky images, in combination with current atmospheric measurements, to produce the DNI forecast. In the end, a robust controller was designed capable of rejecting disturbances within the operating region. Extensive simulation experiments showed that the controller outperforms a finely-tuned multi-loop feedback control strategy. The results obtained suggest that our controller is suitable for practical implementation.

  18. Numerical analysis of using hybrid photovoltaic-thermal solar water heater in Iran

    Directory of Open Access Journals (Sweden)

    M Mohammadi Sarduei

    2017-05-01

    Full Text Available Introduction Electrical performance of solar cells decreases with increasing cell temperature, basically because of growth of the internal charge carrier recombination rates, caused by increased carrier concentrations. Hybrid Photovoltaic/thermal (PVT systems produce electrical and thermal energy simultaneously. PVT solar collectors convert the heat generated in the solar cells to low temperature useful heat energy and so they provide a lower working temperature for solar cells which subsequently leads to a higher electrical efficiency. Recently, in Iran, the reforming government policy in subsidy and increasing fossil fuels price led to growing an interest in use of renewable energies for residual and industrial applications. In spite of this, the PV power generator investment is not economically feasible, so far. Hybrid PVT devices are well known as an alternative method to improve energy performance and therefore economic feasibility of the conventional PV systems. The aim of this study is to investigate the performance of a PVT solar water heater in four different cities of Iran using TRNSYS program. Materials and Methods The designed PVT solar water system consists of two separate water flow circuits namely closed cycle and open circuit. The closed cycle circuit was comprised of a solar PVT collector (with nominal power of 880 W and area of 5.6 m2, a heat exchanger in the tank (with volume of 300 L, a pump and connecting pipes. The water stream in the collector absorbs the heat accumulated in the solar cells and delivers it to the water in the tank though the heat exchanger. An on/off controller system was used to activate the pump when the collector outlet temperature was higher than that of the tank in the closed cycle circuit. The water in the open circuit, comes from city water at low temperature, enters in the lower part of the storage tank where the heat transfer occurs between the two separate circuits. An auxiliary heater, connected

  19. Temperature-dependent thermal properties of spark plasma sintered alumina

    Directory of Open Access Journals (Sweden)

    Saheb Nouari

    2017-01-01

    Full Text Available In this work, we report temperature-dependent thermal properties of alumina powder and bulk alumina consolidated by spark plasma sintering method. The properties were measured between room temperature and 250ºC using a thermal constants analyzer. Alumina powder had very low thermal properties due to the presence of large pores and absence of bonding between its particles. Fully dense alumina with a relative density of 99.6 % was obtained at a sintering temperature of 1400°C and a holding time of 10 min. Thermal properties were found to mainly dependent on density. Thermal conductivity, thermal diffusivity, and specific heat of the fully dense alumina were 34.44 W/mK, 7.62 mm2s-1, and 1.22 J/gK, respectively, at room temperature. Thermal conductivity and thermal diffusivity decreased while specific heat increased with the increase in temperature from room temperature to 250ºC.

  20. Dynamic modeling of a solar receiver/thermal energy storage system based on a compartmented dense gas fluidized bed

    Science.gov (United States)

    Solimene, Roberto; Chirone, Roberto; Chirone, Riccardo; Salatino, Piero

    2017-06-01

    Fluidized beds may be considered a promising option to collection and storage of thermal energy of solar radiation in Concentrated Solar Power (CSP) systems thanks to their excellent thermal properties in terms of bed-to-wall heat transfer coefficient and thermal diffusivity and to the possibility to operate at much higher temperature. A novel concept of solar receiver for combined heat and power (CHP) generation consisting of a compartmented dense gas fluidized bed has been proposed to effectively accomplish three complementary tasks: collection of incident solar radiation, heat transfer to the working fluid of the thermodynamic cycle and thermal energy storage. A dynamical model of the system laid the basis for optimizing collection of incident radiative power, heat transfer to the steam cycle, storage of energy as sensible heat of bed solids providing the ground for the basic design of a 700kWth demonstration CSP plant.

  1. THE EFFECT OF THE THERMAL INERTIA ON THE TEMPERATURE OF A HEATING SLAB.

    Directory of Open Access Journals (Sweden)

    D ABBAZ

    2015-12-01

    Full Text Available The paper presents the influence of the thermal inertia on the temperature of a heated concrete slab. This is a solar sensor provides a solar heating system floor, which the energy input. The concept of thermal inertia is not easy to grasp. It is defined as the speed that helps a system ((building in our case reacts to the change in operating conditions. The response of the building facing to the stresses is largely depending on the thermal properties of constituent materials. This feature is related to good performance, good use, and comfort of the thermal machine which is called ‘‘habitat’’. The objective of this work aims to study the influence of the inertia on the surface temperature of the floor, to design the future of homes with high inertia and very low energy consumption with satisfactory comfort conditions.

  2. Economic Dispatch for Power System Included Wind and Solar Thermal Energy

    Directory of Open Access Journals (Sweden)

    Saoussen BRINI

    2009-07-01

    Full Text Available With the fast development of technologies of alternative energy, the electric power network can be composed of several renewable energy resources. The energy resources have various characteristics in terms of operational costs and reliability. In this study, the problem is the Economic Environmental Dispatching (EED of hybrid power system including wind and solar thermal energies. Renewable energy resources depend on the data of the climate such as the wind speed for wind energy, solar radiation and the temperature for solar thermal energy. In this article it proposes a methodology to solve this problem. The resolution takes account of the fuel costs and reducing of the emissions of the polluting gases. The resolution is done by the Strength Pareto Evolutionary Algorithm (SPEA method and the simulations have been made on an IEEE network test (30 nodes, 8 machines and 41 lines.

  3. Opportunities of solar thermal energy in the industry; Oportunidades de la energia solar termica en la industria

    Energy Technology Data Exchange (ETDEWEB)

    Perches salokangas, J.

    2004-07-01

    The industrial sector means a clear opportunity for the introduction of the solar thermal energy, as the economics, energy and CO2 avoided emissions savings potential is huge. Up to now, the use of solar thermal energy in the industrial sector has not yet been developed because of different technological and economical reasons have interfered in it development. The new solar thermal technologies developed by SOLEL for pure industrial applications, the new flat high efficiency collector SUNPRO, and the solar trough collector IND 300, allow the development of this promising and potential market for the solar thermal energy. (Author)

  4. Mir Cooperative Solar Array Project Accelerated Life Thermal Cycling Test

    Science.gov (United States)

    Hoffman, David J.; Scheiman, David A.

    1996-01-01

    The Mir Cooperative Solar Array (MCSA) project was a joint U.S./Russian effort to build a photovoltaic (PV) solar array and deliver it to the Russian space station Mir. The MCSA will be used to increase the electrical power on Mir and provide PV array performance data in support of Phase 1 of the International Space Station. The MCSA was brought to Mir by space shuttle Atlantis in November 1995. This report describes an accelerated thermal life cycle test which was performed on two samples of the MCSA. In eight months time, two MCSA solar array 'mini' panel test articles were simultaneously put through 24,000 thermal cycles. There was no significant degradation in the structural integrity of the test articles and no electrical degradation, not including one cell damaged early and removed from consideration. The nature of the performance degradation caused by this one cell is briefly discussed. As a result of this test, changes were made to improve some aspects of the solar cell coupon-to-support frame interface on the flight unit. It was concluded from the results that the integration of the U.S. solar cell modules with the Russian support structure would be able to withstand at least 24,000 thermal cycles (4 years on-orbit). This was considered a successful development test.

  5. High-Performance Home Technologies: Solar Thermal & Photovoltaic Systems

    Energy Technology Data Exchange (ETDEWEB)

    Baechler, M.; Gilbride, T.; Ruiz, K.; Steward, H.; Love, P.

    2007-06-01

    This document is the sixth volume of the Building America Best Practices Series. It presents information that is useful throughout the United States for enhancing the energy efficiency practices in the specific climate zones that are presented in the first five Best Practices volumes. It provides an introduction to current photovoltaic and solar thermal building practices. Information about window selection and shading is included.

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

    Science.gov (United States)

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

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

  7. Fuels and chemicals from biomass using solar thermal energy

    Science.gov (United States)

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

    1981-01-01

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

  8. Application of nanomaterials in solar thermal energy storage

    Science.gov (United States)

    Shamshirgaran, Seyed Reza; Khalaji Assadi, Morteza; Viswanatha Sharma, Korada

    2017-12-01

    Solar thermal conversion technology harvests the sun's energy, rather than fossil fuels, to generate low-cost, low/zero-emission energy in the form of heating, cooling or electrical form for residential, commercial, and industrial sectors. The advent of nanofluids and nanocomposites or phase change materials, is a new field of study which is adapted to enhance the efficiency of solar collectors. The concepts of thermal energy storage technologies are investigated and the role of nanomaterials in energy conversion is discussed. This review revealed that although the exploitation of nanomaterials will boost the performance of solar collectors almost in all cases, this would be accompanied by certain challenges such as production cost, instability, agglomeration and erosion. Earlier studies have dealt with the enhancement of thermal conductivity and heat capacity; however, less attention has been given to the facing challenges. Moreover, no exact criteria can be found for the selection of appropriate nanomaterials and their properties for a specific application. In most research studies, the nanoparticles' material and properties have not been selected based on estimated values so that all the aspects of desired application could be considered simultaneously. The wide spread use of nanomaterials can lead to cost effective solutions as well. Therefore, it seems there should be a sense of techno-economic optimization in exploiting nanomaterials for solar thermal energy storage applications. The optimization should cover the key parameters, particularly nanoparticle type, size, loading and shape which depends on the sort of application and also dispersion technology.

  9. Outdoor test method to determine the thermal behavior of solar domestic water heating systems

    Energy Technology Data Exchange (ETDEWEB)

    Garcia-Valladares, O.; Pilatowsky, I. [Centro de Investigacion en Energia, Universidad Nacional Autonoma de Mexico, Privada Xochicalco, s/n, Colonia Centro, 62580 Temixco, Morelos (Mexico); Ruiz, V. [Escuela Tecnica Superior de Ingenieros, Universidad de Sevilla, Camino de los Descubrimientos, s/n, Isla de la Cartuja, 41092 Sevilla, Espana (Spain)

    2008-07-15

    The dynamics of the market, the generation of new promotion programs, fiscal incentives and many other factors are to be considered for the massive application of solar domestic water heating systems (SDWHS) mainly of the compact thermosiphon type, makes it necessary to choose simple and inexpensive procedure tests that permit to know their characteristic thermal behaviors without an official standard being necessary. Moreover, it allows the comparison among systems and offers enough and reliable information to consumers and manufacturers. In most developing countries, an official national standard for SDWHS is not available, therefore it is necessary to adopt an international test procedure in which the cost and time of implementation is very important. In this work, a simple and inexpensive test method to determine the thermal behavior of SDWHS is proposed. Even though these procedure tests do not have an official standard structure they permit, by comparing different solar systems under identical solar, ambient, and initial conditions, the experimental determination of: (a) the maximum available volume of water for solar heating; (b) water temperature increment and available thermal energy at the end of the day; (c) temperature profiles (stratification) and the average temperature in the storage tank after it is homogenized; (d) the average global thermal efficiency; (e) water temperature decrement and energy lost overnight; and (f) the relationship between hot water volume and solar collector area as function of the average heating temperature. An additional proposed test permits to know the heat losses caused by the reverse flow in the collector loop. These tests will be carried out independently of the configuration between the solar collector and the storage tank, the way the fluid circulates and the type of thermal exchange. The results of this procedure test can be very useful, firstly, for the local solar manufacturers' equipment in order to design

  10. Photovoltaic solar panel for a hybrid PV/thermal system

    Energy Technology Data Exchange (ETDEWEB)

    Zakharchenko, R.; Licea-Jimenez, L.; Perez-Garcia, S.A.; Perez-Robles, J.F.; Gonzalez-Hernandez, J.; Vorobiev, Y. [CINVESTAV-Queretaro, (Mexico); Vorobiev, P. [Universidad Autonoma de Queretaro, (Mexico). Facultad de Ingenieria; Dehesa-Carrasco, U. [Instituto Tec. Del Istmo, Oaxaco (Mexico). Dep. de Ingenieria Electromecanica

    2004-05-01

    The hybrid PV-thermal system was studied, with the photovoltaic panel (PVP) area much smaller than that of the solar collector. Performance of the different panels in the system was investigated, in particular, those made of crystalline (c-) Si, {alpha}-Si and CuInSe{sub 2} as well as different materials and constructions for the thermal contact between the panel and the collector. Our conclusion is that the PVP for application in a hybrid system needs a special design providing efficient heat extraction from it. PVP was designed and made. Its study has shown that this design provides the high electrical and thermal efficiency of the hybrid system. (author)

  11. Solar thermal application for the livestock industry in Taiwan

    Directory of Open Access Journals (Sweden)

    Yi-Mei Liu

    2015-09-01

    Full Text Available Solar water heating systems have proven reliable and economical. In Taiwan, the cumulative area of installed solar collectors at the end of 2014 was approximately 2.39 million m2 and approximately 98% of those systems were installed in the domestic sector. Preheating water for livestock processing plants is cost-effective since heated water can be used for evisceration, sanitation during processing and for daily cleanup of plant. In this case study, detailed measurements are reported for parallel combined solar thermal and heat pump systems that are installed in a livestock processing plant. These results confirm that the hot water consumption, the mass flow rate and the operation of circulation and heat pumps affect the system's thermal efficiency. The combined operational effect is a factor in system design. The estimated payback period is less than the expected service period of the system, which validates the financial viability.

  12. Small solar thermal electric power plants with early commercial potential

    Science.gov (United States)

    Jones, H. E.; Bisantz, D. J.; Clayton, R. N.; Heiges, H. H.; Ku, A. C.

    1979-01-01

    Cost-effective small solar thermal electric power plants (1- to 10-MW nominal size) offer an attractive way of helping the world meet its future energy needs. The paper describes the characteristics of a conceptual near-term plant (about 1 MW) and a potential 1990 commercial version. The basic system concept is one in which steam is generated using two-axis tracking, parabolic dish, and point-focusing collectors. The steam is transported through low-loss piping to a central steam turbine generator unit where it is converted to electricity. The plants have no energy storage and their output power level varies with the solar insolation level. This system concept, which is firmly based on state-of-the-art technology, is projected to offer one of the fastest paths for U.S. commercialization of solar thermal electric power plants through moderate technology advances and mass production.

  13. A body temperature model for lizards as estimated from the thermal environment

    NARCIS (Netherlands)

    Fei, T.; Skidmore, A.K.; Venus, V.; Wang, T.; Schlerf, M.; Toxopeus, A.G.; Overjijk, van S.; Bian, B.M.; Liu, Y.

    2012-01-01

    A physically based model was built to predict the transient body temperature of lizards in a thermally heterogeneous environment. Six heat transfer terms were taken into account in this model: solar radiation, convective heat flow, longwave radiation, conductive heat flow, metabolic heat gain and

  14. Computer program determines thermal environment and temperature history of lunar orbiting space vehicles

    Science.gov (United States)

    Head, D. E.; Mitchell, K. L.

    1967-01-01

    Program computes the thermal environment of a spacecraft in a lunar orbit. The quantities determined include the incident flux /solar and lunar emitted radiation/, total radiation absorbed by a surface, and the resulting surface temperature as a function of time and orbital position.

  15. Climate variation based on temperature and solar radiation data ...

    African Journals Online (AJOL)

    Climate variation based on temperature and solar radiation data over a 29 year period in Lilongwe City, Malawi. CC Kaonga, IBM Kosamu, C Tenthani. Abstract. Economies that mainly depend on agriculture are to a large extent being negatively impacted by climate change. In this study, temperature and solar radiation data ...

  16. Solar wind control of stratospheric temperatures in Jupiter's auroral regions?

    Science.gov (United States)

    Sinclair, James Andrew; Orton, Glenn; Kasaba, Yasumasa; Sato, Takao M.; Tao, Chihiro; Waite, J. Hunter; Cravens, Thomas; Houston, Stephen; Fletcher, Leigh; Irwin, Patrick; Greathouse, Thomas K.

    2017-10-01

    Auroral emissions are the process through which the interaction of a planet’s atmosphere and its external magnetosphere can be studied. Jupiter exhibits auroral emission at a multitude of wavelengths including the X-ray, ultraviolet and near-infrared. Enhanced emission of CH4 and other stratospheric hydrocarbons is also observed coincident with Jupiter’s shorter-wavelength auroral emission (e.g. Caldwell et al., 1980, Icarus 44, 667-675, Kostiuk et al., 1993, JGR 98, 18823). This indicates that auroral processes modify the thermal structure and composition of the auroral stratosphere. The exact mechanism responsible for this auroral-related heating of the stratosphere has however remained elusive (Sinclair et al., 2017a, Icarus 292, 182-207, Sinclair et al., 2017b, GRL, 44, 5345-5354). We will present an analysis of 7.8-μm images of Jupiter measured by COMICS (Cooled Mid-Infrared Camera and Spectrograph, Kataza et al., 2000, Proc. SPIE(4008), 1144-1152) on the Subaru telescope. These images were acquired on January 11th, 12th, 13th, 14th, February 4, 5th and May 17th, 18th, 19th and 20th in 2017, allowing the daily variability of Jupiter’s auroral-related stratospheric heating to be tracked. Preliminary results suggest lower stratospheric temperatures are directly forced by the solar wind dynamical pressure. The southern auroral hotspot exhibited a significant increase in brightness temperature over a 24-hour period. Over the same time period, a solar wind propagation model (Tao et al. 2005, JGR 110, A11208) predicts a strong increase in the solar wind dynamical pressure at Jupiter.

  17. A Novel Approach to Thermal Design of Solar Modules: Selective-Spectral and Radiative Cooling

    Energy Technology Data Exchange (ETDEWEB)

    Sun, Xingshu; Dubey, Rajiv; Chattopadhyay, Shashwata; Khan, Mohammad Ryyan; Chavali, Raghu Vamsi; Silverman, Timothy J.; Kottantharayil, Anil; Vasi, Juzer; Alam, Muhammad Ashraful

    2016-11-21

    For commercial solar modules, up to 80% of the incoming sunlight may be dissipated as heat, potentially raising the temperature 20-30 degrees C higher than the ambient. In the long run, extreme self-heating may erode efficiency and shorten lifetime, thereby, dramatically reducing the total energy output by almost ~10% Therefore, it is critically important to develop effective and practical cooling methods to combat PV self-heating. In this paper, we explore two fundamental sources of PV self-heating, namely, sub-bandgap absorption and imperfect thermal radiation. The analysis suggests that we redesign the optical and thermal properties of the solar module to eliminate the parasitic absorption (selective-spectral cooling) and enhance the thermal emission to the cold cosmos (radiative cooling). The proposed technique should cool the module by ~10 degrees C, to be reflected in significant long-term energy gain (~ 3% to 8% over 25 years) for PV systems under different climatic conditions.

  18. Radiative cooling of solar absorbers using a visibly transparent photonic crystal thermal blackbody

    Science.gov (United States)

    Zhu, Linxiao; Raman, Aaswath P.; Fan, Shanhui

    2015-01-01

    A solar absorber, under the sun, is heated up by sunlight. In many applications, including solar cells and outdoor structures, the absorption of sunlight is intrinsic for either operational or aesthetic considerations, but the resulting heating is undesirable. Because a solar absorber by necessity faces the sky, it also naturally has radiative access to the coldness of the universe. Therefore, in these applications it would be very attractive to directly use the sky as a heat sink while preserving solar absorption properties. Here we experimentally demonstrate a visibly transparent thermal blackbody, based on a silica photonic crystal. When placed on a silicon absorber under sunlight, such a blackbody preserves or even slightly enhances sunlight absorption, but reduces the temperature of the underlying silicon absorber by as much as 13 °C due to radiative cooling. Our work shows that the concept of radiative cooling can be used in combination with the utilization of sunlight, enabling new technological capabilities. PMID:26392542

  19. Radiative cooling of solar absorbers using a visibly transparent photonic crystal thermal blackbody.

    Science.gov (United States)

    Zhu, Linxiao; Raman, Aaswath P; Fan, Shanhui

    2015-10-06

    A solar absorber, under the sun, is heated up by sunlight. In many applications, including solar cells and outdoor structures, the absorption of sunlight is intrinsic for either operational or aesthetic considerations, but the resulting heating is undesirable. Because a solar absorber by necessity faces the sky, it also naturally has radiative access to the coldness of the universe. Therefore, in these applications it would be very attractive to directly use the sky as a heat sink while preserving solar absorption properties. Here we experimentally demonstrate a visibly transparent thermal blackbody, based on a silica photonic crystal. When placed on a silicon absorber under sunlight, such a blackbody preserves or even slightly enhances sunlight absorption, but reduces the temperature of the underlying silicon absorber by as much as 13 °C due to radiative cooling. Our work shows that the concept of radiative cooling can be used in combination with the utilization of sunlight, enabling new technological capabilities.

  20. Solar High Temperature Water-Splitting Cycle with Quantum Boost

    Energy Technology Data Exchange (ETDEWEB)

    Taylor, Robin [SAIC; Davenport, Roger [SAIC; Talbot, Jan [UCSD; Herz, Richard [UCSD; Genders, David [Electrosynthesis Co.; Symons, Peter [Electrosynthesis Co.; Brown, Lloyd [TChemE

    2014-04-25

    A sulfur family chemical cycle having ammonia as the working fluid and reagent was developed as a cost-effective and efficient hydrogen production technology based on a solar thermochemical water-splitting cycle. The sulfur ammonia (SA) cycle is a renewable and sustainable process that is unique in that it is an all-fluid cycle (i.e., with no solids handling). It uses a moderate temperature solar plant with the solar receiver operating at 800°C. All electricity needed is generated internally from recovered heat. The plant would operate continuously with low cost storage and it is a good potential solar thermochemical hydrogen production cycle for reaching the DOE cost goals. Two approaches were considered for the hydrogen production step of the SA cycle: (1) photocatalytic, and (2) electrolytic oxidation of ammonium sulfite to ammonium sulfate in aqueous solutions. Also, two sub-cycles were evaluated for the oxygen evolution side of the SA cycle: (1) zinc sulfate/zinc oxide, and (2) potassium sulfate/potassium pyrosulfate. The laboratory testing and optimization of all the process steps for each version of the SA cycle were proven in the laboratory or have been fully demonstrated by others, but further optimization is still possible and needed. The solar configuration evolved to a 50 MW(thermal) central receiver system with a North heliostat field, a cavity receiver, and NaCl molten salt storage to allow continuous operation. The H2A economic model was used to optimize and trade-off SA cycle configurations. Parametric studies of chemical plant performance have indicated process efficiencies of ~20%. Although the current process efficiency is technically acceptable, an increased efficiency is needed if the DOE cost targets are to be reached. There are two interrelated areas in which there is the potential for significant efficiency improvements: electrolysis cell voltage and excessive water vaporization. Methods to significantly reduce water evaporation are

  1. Comparison of Observed Surface Temperatures of 4 Vesta to the KRC Thermal Model

    Science.gov (United States)

    Titus, T. N.; Becker, K. J.; Anderson, J. A.; Capria, M. T.; Tosi, F.; DeSanctis, M. C.; Palomba, E.; Grassi, D.; Capaccioni, F.; Ammannito, E.; hide

    2012-01-01

    In this work, we will compare ob-served temperatures of the surface of Vesta using data acquired by the Dawn [1] Visible and Infrared Map-ping Spectrometer (VIR-MS) [2] during the approach phase to model results from the KRC thermal model. High thermal inertia materials, such as bedrock, resist changes in temperature while temperatures of low thermal inertia material, such as dust, respond quickly to changes in solar insolation. The surface of Vesta is expected to have low to medium thermal inertia values, with the most commonly used value being extremely low at 15 TIU [4]. There are several parameters which affect observed temperatures in addition to thermal inertia: bond albedo, slope, and surface roughness. In addition to these parameters, real surfaces are rarely uniform monoliths that can be described by a single thermal inertia value. Real surfaces are often vertically layered or are mixtures of dust and rock. For Vesta's surface, with temperature extremes ranging from 50 K to 275 K and no atmosphere, even a uniform monolithic surface may have non-uniform thermal inertia due to temperature dependent thermal conductivity.

  2. Techno-Economic Assessment of Heat Transfer Fluid Buffering for Thermal Energy Storage in the Solar Field of Parabolic Trough Solar Thermal Power Plants

    Directory of Open Access Journals (Sweden)

    Jorge M. Llamas

    2017-08-01

    Full Text Available Currently, operating parabolic trough (PT solar thermal power plants, either solar-only or with thermal storage block, use the solar field as a heat transfer fluid (HTF thermal storage system to provide extra thermal capacity when it is needed. This is done by circulating heat transfer fluid into the solar field piping in order to create a heat fluid buffer. In the same way, by oversizing the solar field, it can work as an alternative thermal energy storage (TES system to the traditionally applied methods. This paper presents a solar field TES model for a standard solar field from a 50-MWe solar power plant. An oversized solar model is analyzed to increase the capacity storage system (HTF buffering. A mathematical model has been developed and different simulations have been carried out over a cycle of one year with six different solar multiples considered to represent the different oversized solar field configurations. Annual electricity generation and levelized cost of energy (LCOE are calculated to find the solar multiple (SM which makes the highest solar field thermal storage capacity possible within the minimum LCOE.

  3. Study on effectiveness of continuous solar dryer integrated with desiccant thermal storage for drying cocoa beans

    OpenAIRE

    Dina, Sari Farah; Ambarita, Himsar; Farel H. Napitupulu; Kawai, Hideki

    2015-01-01

    The main objective is to assess effectiveness of continuous solar dryer integrated with desiccant thermal storage for drying cocoa beans. Two type of desiccants were tested, molecular sieve 13× (Na86 [(AlO2)86·(SiO2)106]·264H2O) as an adsorbent type and CaCl2 as an absorbent type. The results revealed that during sunshine hours, the maximum temperature within the drying chamber varied from 40 °C to 54 °C. In average, it was 9–12 °C higher than ambient temperature. These temperatures are very ...

  4. Design Considerations for Space Transfer Vehicles Using Solar Thermal Propulsion

    Science.gov (United States)

    Emrich, William J.

    1995-01-01

    The economical deployment of satellites to high energy earth orbits is crucial to the ultimate success of this nations commerical space ventures and is highly desirable for deep space planetary missions requiring earth escape trajectories. Upper stage space transfer vehicles needed to accomplish this task should ideally be simple, robust, and highly efficient. In this regard, solar thermal propulsion is particularly well suited to those missions where high thrust is not a requirement. The Marshall Space Flight Center is , therefore, currently engaged in defining a transfer vehicle employing solar thermal propulsion capable of transferring a 1000 lb. payload from low Earth orbit (LEO) to a geostationary Earth orbit (GEO) using a Lockheed launch vehicle (LLV3) with three Castors and a large shroud. The current design uses liquid hydrogen as the propellant and employs two inflatable 16 x 24 feet eliptical off-axis parabolic solar collectors to focus sunlight onto a tungsten/rhenium windowless black body type absorber. The concentration factor on this design is projected to be approximately 1800:1 for the primary collector and 2.42:1 for the secondary collector for an overall concentration factor of nearly 4400:1. The engine, which is about twice as efficient as the best currently available chemical engines, produces two pounds of thrust with a specific impulse (Isp) of 860 sec. Transfer times to GEO are projected to be on the order of one month. The launch and deployed configurations of the solar thermal upper stage (STUS) are depicted.

  5. Galileo probe measurements of thermal and solar radiation fluxes in the Jovian atmosphere

    Science.gov (United States)

    Sromovsky, L. A.; Collard, A. D.; Fry, P. M.; Orton, G. S.; Lemmon, M. T.; Tomasko, M. G.; Freedman, R. S.

    1998-09-01

    The Galileo probe net flux radiometer (NFR) measured radiation fluxes in Jupiter's atmosphere from about 0.44 to 14 bars, using five spectral channels to separate solar and thermal components. Onboard calibration results confirm that the NFR responded to radiation approximately as expected. NFR channels also responded to a superimposed thermal perturbation, which can be approximately removed using blind channel measurements and physical constraints. Evidence for the expected NH3 cloud was seen in the spectral character of spin-induced modulations of the direct solar beam signals. These results are consistent with an overlying cloud of small NH3 ice particles (0.5-0.75 μm in radius) of optical depth 1.5-2 at 0.5 μm. Such a cloud would have so little effect on thermal fluxes that NFR thermal channels provide no additional constraints on its properties. However, evidence for heating near 0.45 bar in the NFR thermal channels would seem to require either an additional opacity source beyond this small-particle cloud, implying a heterogeneous cloud structure to avoid conflicts with solar modulation results, or a change in temperature lapse rate just above the probe measurements. The large thermal flux levels imply water vapor mixing ratios that are only 6% of solar at 10 bars, but possibly increasing with depth, and significantly subsaturated ammonia at pressures less than 3 bars. If deep NH3 mixing ratios at the probe entry site are 3-4 times ground-based inferences, as suggested by probe radio signal attenuation, then only half as much water is needed to match NFR observations. No evidence of a water cloud was seen near the 5-bar level. The 5-μm thermal channel detected the presumed NH4SH cloud base near 1.35 bars. Effects of this cloud were also seen in the solar channel upflux measurements but not in the solar net fluxes, implying that the cloud is a conservative scatterer of sunlight. The minor thermal signature of this cloud is compatible with particle radii near

  6. Reducing interior temperature resulting from solar energy using three-dimensional surface patterns

    Directory of Open Access Journals (Sweden)

    Shiang-Jiun Lin

    2015-05-01

    Full Text Available Excessive solar energy can significantly increase interior temperatures and yield great energy demands for air conditioning. Whereas reducing energy consumptions is very crucial today, this article employs patterned glass technology which incorporates linear patterns throughout the exterior surface of glass to attenuate the solar effect on the interior thermal field based on theoretical and experimental studies. By periodically imposing linearly three-dimensional patterns over the outer surface of window glass, the analytical results indicate that the interior solar heat is able to be reduced, as the surface patterns increase the incident angle and/or decrease the solar energy loading on the patterned glass material. Moreover, the interior solar heat can be strongly affected by the pattern design. According to thermally measured results, the trapezoidal patterned glass having 3-mm-top-edged patterned members yields lower temperature on the interior surface of glass comparing with that for the trapezoidal patterns having 6-mm-top edges. Therefore, making the least non-sloped feature or flat plane appearing on the patterned glass helps decrease the interior temperature resulting from solar energy.

  7. Hybrid Solar: A Review on Photovoltaic and Thermal Power Integration

    Directory of Open Access Journals (Sweden)

    T. T. Chow

    2012-01-01

    Full Text Available The market of solar thermal and photovoltaic electricity generation is growing rapidly. New ideas on hybrid solar technology evolve for a wide range of applications, such as in buildings, processing plants, and agriculture. In the building sector in particular, the limited building space for the accommodation of solar devices has driven a demand on the use of hybrid solar technology for the multigeneration of active power and/or passive solar devices. The importance is escalating with the worldwide trend on the development of low-carbon/zero-energy buildings. Hybrid photovoltaic/thermal (PVT collector systems had been studied theoretically, numerically, and experimentally in depth in the past decades. Together with alternative means, a range of innovative products and systems has been put forward. The final success of the integrative technologies relies on the coexistence of robust product design/construction and reliable system operation/maintenance in the long run to satisfy the user needs. This paper gives a broad review on the published academic works, with an emphasis placed on the research and development activities in the last decade.

  8. EVALUATION OF FLAT-PLATE PHOTOVOLTAIC THERMAL HYBRID SYSTEMS FOR SOLAR ENERGY UTILIZATION.

    Energy Technology Data Exchange (ETDEWEB)

    ANDREWS,J.W.

    1981-06-01

    The technical and economic attractiveness of combined photovoltaic/thermal (PV/T) solar energy collectors was evaluated. The study was limited to flat-plate collectors since concentrating photovoltaic collectors require active cooling and thus are inherently PV/T collectors, the only decision being whether to use the thermal energy or to dump it. it was also specified at the outset that reduction in required roof area was not to be used as an argument for combining the collection of thermal and electrical energy into one module. Three tests of economic viability were identified, all of which PV/T must pass if it is to be considered a promising alternative: PV/T must prove to be competitive with photovoltaic-only, thermal-only, and side-by-side photovoltaic-plus-thermal collectors and systems. These three tests were applied to systems using low-temperature (unglazed) collectors and to systems using medium-temperature (glazed) collectors in Los Angeles, New York, and Tampa. For photovoltaics, the 1986 DOE cost goals were assumed to have been realized, and for thermal energy collection two technologies were considered: a current technology based on metal and glass, and a future technology based on thin-film plastics. The study showed that for medium-temperature applications PV/T is not an attractive option in any of the locations studied. For low-temperature applications, PV/T appears to be marginally attractive.

  9. On the potential of solar cells to efficiently operate at high temperature

    Science.gov (United States)

    Zeitouny, Joya; Lalau, Noémie; Katz, Eugene A.; Dollet, Alain; Vossier, Alexis

    2017-09-01

    The development of high temperature CPV/thermal (CSP) hybrid systems appears to be a promising route to improve the overall solar to electricity conversion efficiency. Moreover, such systems would not only use the residual heat stemming from the unconverted fraction of the incident solar radiation in PV cells, but they would also provide the advantage of storing energy as heat. However, the performances of such hybrid systems depend strongly on the temperature of the thermal receivers which are only effective at high temperatures (typically above 250°C) while solar cells typically operate at temperatures close to ambient. An appropriate strategy is to make PV cells efficiently operate at temperature levels significantly exceeding the normal range of temperatures for which they are commonly designed. The degradation of electrical performance associated with high working temperature is less pronounced when the cell is submitted to high sunlight concentrations. An efficient photovoltaic conversion at temperature levels exceeding the ambient may however require significant modifications in the architecture of the cells. In this work, we assessed the feasibility of this strategy by studying the electrical properties as well as the overall efficiency of the PV/CSP system at different temperatures and sunlight illuminations.

  10. Effect of Regenerative Organic Rankine Cycle (RORC on the Performance of Solar Thermal Power in Yogyakarta, Indonesia

    Directory of Open Access Journals (Sweden)

    Ghalya Pikra

    2013-07-01

    Full Text Available This paper presents effect of Regenerative Organic Rankine Cycle (RORC on the performance of solar thermal power in Yogyakarta, Indonesia. Solar thermal power is a plant that uses solar energy as heat source. Indonesia has high humidity level, so that parabolic trough is the most suitable type of solar thermal power technology to be developed, where the design is made with small focal distance. Organic Rankine Cycle (ORC is a Rankine cycle that use organic fluid as working fluid to utilize low temperature heat sources. RORC is used to increase ORC performance. The analysis was done by comparing ORC system with and without regenerator addition. Refrigerant that be used in the analysis is R123. Preliminary data was taken from the solar collector system that has been installed in Yogyakarta. The analysis shows that with 36 m total parabolic length, the resulting solar collector capacity is 63 kW, heat input/evaporator capacity is determined 26.78 kW and turbine power is 3.11 kW for ORC, and 3.38 kW for RORC. ORC thermal efficiency is 11.28% and RORC is 12.26%. Overall electricity efficiency is 4.93% for ORC, and 5.36% for RORC. With 40°C condensing temperature and evaporation at 10 bar saturated condition, efficiency of RORC is higher than ORC. Greater evaporation temperature at the same pressure (10 bar provide greater turbine power and efficiency.

  11. Expanding Thermal Plasma Chemical Vapour Deposition of ZnO:Al Layers for CIGS Solar Cells

    Directory of Open Access Journals (Sweden)

    K. Sharma

    2014-01-01

    Full Text Available Aluminium-doped zinc oxide (ZnO:Al grown by expanding thermal plasma chemical vapour deposition (ETP-CVD has demonstrated excellent electrical and optical properties, which make it an attractive candidate as a transparent conductive oxide for photovoltaic applications. However, when depositing ZnO:Al on CIGS solar cell stacks, one should be aware that high substrate temperature processing (i.e., >200°C can damage the crucial underlying layers/interfaces (such as CIGS/CdS and CdS/i-ZnO. In this paper, the potential of adopting ETP-CVD ZnO:Al in CIGS solar cells is assessed: the effect of substrate temperature during film deposition on both the electrical properties of the ZnO:Al and the eventual performance of the CIGS solar cells was investigated. For ZnO:Al films grown using the high thermal budget (HTB condition, lower resistivities, ρ, were achievable (~5 × 10−4 Ω·cm than those grown using the low thermal budget (LTB conditions (~2 × 10−3 Ω·cm, whereas higher CIGS conversion efficiencies were obtained for the LTB condition (up to 10.9% than for the HTB condition (up to 9.0%. Whereas such temperature-dependence of CIGS device parameters has previously been linked with chemical migration between individual layers, we demonstrate that in this case it is primarily attributed to the prevalence of shunt currents.

  12. Midtemperature Solar Systems Test Facility predictions for thermal performance based on test data. Alpha Solarco Model 104 solar collector with 0. 125-inch Schott low-iron glass reflector surface

    Energy Technology Data Exchange (ETDEWEB)

    Harrison, T.D.

    1981-04-01

    Thermal performance predictions based on test data are presented for the Alpha Solarco Model 104 solar collector, with 0.125-inch Schott low-iron glass reflector surface, for three output temperatures at five cities in the United States.

  13. Thermal Characteristics of Multilayer Insulation Materials for Flexible Thin-Film Solar Cell Array of Stratospheric Airship

    Directory of Open Access Journals (Sweden)

    Kangwen Sun

    2014-01-01

    Full Text Available Flexible thin-film solar cell is an efficient energy system on the surface of stratospheric airship for utilizing the solar energy. In order to ensure the normal operation of airship platform, the thermal control problem between the flexible thin-film solar cell and the airship envelope should be properly resolved. In this paper, a multilayer insulation material (MLI is developed first, and low temperature environment test is carried out to verify the insulation effect of MLI. Then, a thermal heat transfer model of flexible thin-film solar cell and MLI is proposed, and the equivalent thermal conductivity coefficients of flexible thin-film solar cell and Nomex honeycomb are calculated based on the environment test and the temperature profile of flexible thin-film solar cell versus each layer of MLI. Finally, FLUENT is used for modeling and simulation analysis on the flexible thin-film solar cell and MLI, and the simulation results agree well with the experimental data, which validate the correctness of the proposed heat transfer model of MLI. In some way, our study can provide helpful support for further engineering applications of flexible thin-film solar cell.

  14. Investigation on medium temperature heat pipe receiver used in parabolic trough solar collector

    Energy Technology Data Exchange (ETDEWEB)

    Zhan, Dongdong; Zhang, Hong; Liu, Yun; Li, Sihai; Zhuang, Jun [Nanjing Univ. of Technology (China). Inst. of Thermal Energy Engineering

    2008-07-01

    In this paper, a novel medium temperature (250{proportional_to}500 C) heat pipe receiver was developed for parabolic trough solar collector and the feasibility study on the receiver was carried out. The lifetime analysis, thermal analysis and economic analysis of the heat pipe receiver were presented. The result showed that the heat pipe receiver was flexible, easily maintained, low manufacture cost and could be working reliability in the temperature and heat flux conditions of parabolic trough solar collector with a high heat collect efficiency. (orig.)

  15. A temperature dependent slip factor based thermal model for friction ...

    Indian Academy of Sciences (India)

    This paper proposes a new slip factor based three-dimensional thermal model to predict the temperature distribution during friction stir welding of 304L stainless steel plates. The proposed model employs temperature and radius dependent heat source to study the thermal cycle, temperature distribution, power required, the ...

  16. A temperature dependent slip factor based thermal model for friction ...

    Indian Academy of Sciences (India)

    Abstract. This paper proposes a new slip factor based three-dimensional thermal model to predict the temperature distribution during friction stir welding of 304L stainless steel plates. The proposed model employs temperature and radius dependent heat source to study the thermal cycle, temperature distribution, power ...

  17. Numerical thermal back-calculation of the Kerava Solar Village underground thermal energy storage

    OpenAIRE

    Oosterbaan, Harm; Janiszewski, Mateusz; Uotinen, Lauri; Siren, Topias; Rinne, Mikael

    2017-01-01

    With increasing pressure to reduce the fraction of energy coming from fossil fuels, there is an increased need for research into feasible, and sustainable energy sources, such as solar energy. The problem with solar energy is the mismatch between supply and demand, and so the energy needs to be stored. This research paper is a part of the project titled “Tackling the Challenges of a Solar-Community Concept in High Latitudes”, and aims in helping to design a thermal energy storage system for s...

  18. In-depth investigation of spin-on doped solar cells with thermally grown oxide passivation

    Directory of Open Access Journals (Sweden)

    Samir Mahmmod Ahmad

    Full Text Available Solar cell industrial manufacturing, based largely on proven semiconductor processing technologies supported by significant advancements in automation, has reached a plateau in terms of cost and efficiency. However, solar cell manufacturing cost (dollar/watt is still substantially higher than fossil fuels. The route to lowering cost may not lie with continuing automation and economies of scale. Alternate fabrication processes with lower cost and environmental-sustainability coupled with self-reliance, simplicity, and affordability may lead to price compatibility with carbon-based fuels. In this paper, a custom-designed formulation of phosphoric acid has been investigated, for n-type doping in p-type substrates, as a function of concentration and drive-in temperature. For post-diffusion surface passivation and anti-reflection, thermally-grown oxide films in 50–150-nm thickness were grown. These fabrication methods facilitate process simplicity, reduced costs, and environmental sustainability by elimination of poisonous chemicals and toxic gases (POCl3, SiH4, NH3. Simultaneous fire-through contact formation process based on screen-printed front surface Ag and back surface through thermally grown oxide films was optimized as a function of the peak temperature in conveyor belt furnace. Highest efficiency solar cells fabricated exhibited efficiency of ∼13%. Analysis of results based on internal quantum efficiency and minority carried measurements reveals three contributing factors: high front surface recombination, low minority carrier lifetime, and higher reflection. Solar cell simulations based on PC1D showed that, with improved passivation, lower reflection, and high lifetimes, efficiency can be enhanced to match with commercially-produced PECVD SiN-coated solar cells. Keywords: Crystalline Si solar cells, Phosphoric acid spin-on doping, Screen printing, Thermal oxide passivation

  19. Solar photovoltaic/thermal residential experiment. Phase I. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Darkazalli, G.

    1980-07-01

    Month-by-month energy transfer data between an occupied residence and its energy supply systems are presented. The data were obtained during the first phase of photovoltaic/thermal residential research conducted at the University of Texas at Arlington/Solar Energy Research Facility. This research was part of the US Department of Energy Photovoltaic/Thermal Project managed by the M.I.T. Lincoln Laboratory. Energy transfer data are divided into different categories depending on how the energy is consumed. Energy transfers between some system components are also categorized. These components include a flat-plate thermal collector array, a flat-plate photovoltaic array, a dc-to-ac inverter, thermal storage tanks, and a series heat pump. System operations included directing surplus electrical energy (generated by the photovoltaic array) into the local utility grid. The heat pump used off-peak utility power to chill water during the cooling season.

  20. Thermal solar power. New Schemes of Principle. Multifamily facilities and his problems; Energia solar termica. Instalaciones multifamiliares y su problematica. Nuevos esquemas de principio

    Energy Technology Data Exchange (ETDEWEB)

    Acedo, M. A.

    2008-07-01

    Article checks the production of warm sanitary water no-central facilities for thermal solar power of low temperature in the multifamily buildings. In order that the governmental incentives are destined only to the objectively well facilities, also some technical problems are checked. (Author)

  1. Heat conductivity of high-temperature thermal insulators

    Science.gov (United States)

    Kharlamov, A. G.

    The book deals essentially with the mechanisms of heat transfer by conduction, convection, and thermal radiation in absorbing and transmitting media. Particular attention is given to materials for gas-cooled reactor systems, the temperature dependent conductivities of high-temperature insulations in vacuum, and the thermal conductivities of MgO, Al2O3, ZrO2, and other powders at temperatures up to 2000 C. The thermal conductivity of pyrolitic graphite and graphite foam are studied.

  2. Irrigation market for solar thermal parabolic dish systems

    Science.gov (United States)

    Habib-Agahi, H.; Jones, S. C.

    1981-01-01

    The potential size of the onfarm-pumped irrigation market for solar thermal parabolic dish systems in seven high-insolation states is estimated. The study is restricted to the displacement of three specific fuels: gasoline, diesel and natural gas. The model was developed to estimate the optimal number of parabolic dish modules per farm based on the minimum cost mix of conventional and solar thermal energy required to meet irrigation needs. The study concludes that the potential market size for onfarm-pumped irrigation applications ranges from 101,000 modules when a 14 percent real discount rate is assumed to 220,000 modules when the real discount rate drops to 8 percent. Arizona, Kansas, Nebraska, New Mexico and Texas account for 98 percent of the total demand for this application, with the natural gas replacement market accounting for the largest segment (71 percent) of the total market.

  3. Solid state phase change materials for thermal energy storage in passive solar heated buildings

    Science.gov (United States)

    Benson, D. K.; Christensen, C.

    1983-11-01

    A set of solid state phase change materials was evaluated for possible use in passive solar thermal energy storage systems. The most promising materials are organic solid solutions of pentaerythritol, pentaglycerine and neopentyl glycol. Solid solution mixtures of these compounds can be tailored so that they exhibit solid-to-solid phase transformations at any desired temperature within the range from less than 25 deg to 188 deg. Thermophysical properties such as thermal conductivity, density and volumetric expansion were measured. Computer simulations were used to predict the performance of various Trombe wall designs incorporating solid state phase change materials. Optimum performance was found to be sensitive to the choice of phase change temperatures and to the thermal conductivity of the phase change material. A molecular mechanism of the solid state phase transition is proposed and supported by infrared spectroscopic evidence.

  4. Thermal design, analysis and comparison on three concepts of space solar power satellite

    Science.gov (United States)

    Yang, Chen; Hou, Xinbin; Wang, Li

    2017-08-01

    Space solar power satellites (SSPS) have been widely studied as systems for collecting solar energy in space and transmitting it wirelessly to earth. A previously designed planar SSPS concept collects solar power in two huge arrays and then transmits it through one side of the power-conduction joint to the antenna. However, the system's one group of power-conduction joints may induce a single point of failure. As an SSPS concept, the module symmetrical concentrator (MSC) architecture has many advantages. This architecture can help avoid the need for a large, potentially failure-prone conductive rotating joint and limit wiring mass. However, the thermal control system has severely restricted the rapid development of MSC, especially in the sandwich module. Because of the synchronous existence of five suns concentration and solar external heat flux, the sandwich module will have a very high temperature, which will surpass the permissible temperature of the solar cells. Recently, an alternate multi-rotary joints (MR) SSPS concept was designed by the China Academy of Space Technology (CAST). This system has multiple joints to avoid the problem of a single point of failure. Meanwhile, this concept has another advantage for reducing the high power and heat removal in joints. It is well known to us that, because of the huge external flux in SSPS, the thermal management sub-system is an important component that cannot be neglected. Based on the three SSPS concepts, this study investigated the thermal design and analysis of a 1-km, gigawatt-level transmitting antenna in SSPS. This study compares the thermal management sub-systems of power-conduction joints in planar and MR SSPS. Moreover, the study considers three classic thermal control architectures of the MSC's sandwich module: tile, step, and separation. The study also presents an elaborate parameter design, analysis and discussion of step architecture. Finally, the results show the thermal characteristics of each SSPS

  5. SolarOil Project, Phase I preliminary design report. [Solar Thermal Enhanced Oil Recovery project

    Energy Technology Data Exchange (ETDEWEB)

    Baccaglini, G.; Bass, J.; Neill, J.; Nicolayeff, V.; Openshaw, F.

    1980-03-01

    The preliminary design of the Solar Thermal Enhanced Oil Recovery (SolarOil) Plant is described in this document. This plant is designed to demonstrate that using solar thermal energy is technically feasible and economically viable in enhanced oil recovery (EOR). The SolarOil Plant uses the fixed mirror solar concentrator (FMSC) to heat high thermal capacity oil (MCS-2046) to 322/sup 0/C (611/sup 0/F). The hot fluid is pumped from a hot oil storage tank (20 min capacity) through a once-through steam generator which produces 4.8 MPa (700 psi) steam at 80% quality. The plant net output, averaged over 24 hr/day for 365 days/yr, is equivalent to that of a 2.4 MW (8.33 x 10/sup 6/ Btu/hr) oil-fired steam generator having an 86% availability. The net plant efficiency is 57.3% at equinox noon, a 30%/yr average. The plant will be demonstrated at an oilfield site near Oildale, California.

  6. A solar air collector with integrated latent heat thermal storage

    Science.gov (United States)

    Charvat, Pavel; Ostry, Milan; Mauder, Tomas; Klimes, Lubomir

    2012-04-01

    Simulations of the behaviour of a solar air collector with integrated latent heat thermal storage were performed. The model of the collector was created with the use of coupling between TRNSYS 17 and MATLAB. Latent heat storage (Phase Change Material - PCM) was integrated with the solar absorber. The model of the latent heat storage absorber was created in MATLAB and the model of the solar air collector itself was created in TRNSYS with the use of TYPE 56. The model of the latent heat storage absorber allows specification of the PCM properties as well as other parameters. The simulated air collector was the front and back pass collector with the absorber in the middle of the air cavity. Two variants were considered for comparison; the light-weight absorber made of sheet metal and the heat-storage absorber with the PCM. Simulations were performed for the climatic conditions of the Czech Republic (using TMY weather data).

  7. Solar thermal plant impact analysis and requirements definition

    Science.gov (United States)

    Gupta, Y. P.

    1980-01-01

    Progress on a continuing study comprising of ten tasks directed at defining impact and requirements for solar thermal power systems (SPS), 1 to 10 MWe each in capacity, installed during 1985 through year 2000 in a utility or a nonutility load in the United States is summarized. The point focus distributed receiver (PFDR) solar power systems are emphasized. Tasks 1 through 4, completed to date, include the development of a comprehensive data base on SPS configurations, their performance, cost, availability, and potential applications; user loads, regional characteristics, and an analytic methodology that incorporates the generally accepted utility financial planning methods and several unique modifications to treat the significant and specific characteristics of solar power systems deployed in either central or distributed power generation modes, are discussed.

  8. Macroeconomic impact of the Solar Thermal Electricity Industry in Spain

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2011-10-15

    In the last three years, Solar Thermal Electricity (STE) in Spain has grown significantly. Its weight within the renewables mix is becoming relevant, and even more so, its impact on economics, society, the environment, and reducing energy dependence. This report was carried out by Deloitte for Protermosolar to quantitatively and qualitatively evaluate the main macroeconomic variables derived from the development of this technology in Spain from 2008 to 2010, and forecast its possible future impact.

  9. Solar Energy.

    Science.gov (United States)

    Eaton, William W.

    Presented is the utilization of solar radiation as an energy resource principally for the production of electricity. Included are discussions of solar thermal conversion, photovoltic conversion, wind energy, and energy from ocean temperature differences. Future solar energy plans, the role of solar energy in plant and fossil fuel production, and…

  10. Effects of Absorber Emissivity on Thermal Performance of a Solar Cavity Receiver

    Directory of Open Access Journals (Sweden)

    Jiabin Fang

    2014-01-01

    Full Text Available Solar cavity receiver is a key component to realize the light-heat conversion in tower-type solar power system. It usually has an aperture for concentrated sunlight coming in, and the heat loss is unavoidable because of this aperture. Generally, in order to improve the thermal efficiency, a layer of coating having high absorptivity for sunlight would be covered on the surface of the absorber tubes inside the cavity receiver. As a result, it is necessary to investigate the effects of the emissivity of absorber tubes on the thermal performance of the receiver. In the present work, the thermal performances of the receiver with different absorber emissivity were numerically simulated. The results showed that the thermal efficiency increases and the total heat loss decreases with increasing emissivity of absorber tubes. However, the thermal efficiency increases by only 1.6% when the emissivity of tubes varies from 0.2 to 0.8. Therefore, the change of absorber emissivity has slight effect on the thermal performance of the receiver. The reason for variation tendency of performance curves was also carefully analyzed. It was found that the temperature reduction of the cavity walls causes the decrease of the radiative heat loss and the convective heat loss.

  11. Thermal Analysis and Correlation of the Mars Odyssey Spacecraft's Solar Array During Aerobraking Operations

    Science.gov (United States)

    Dec, John A.; Gasbarre, Joseph F.; George, Benjamin E.

    2002-01-01

    The Mars Odyssey spacecraft made use of multipass aerobraking to gradually reduce its orbit period from a highly elliptical insertion orbit to its final science orbit. Aerobraking operations provided an opportunity to apply advanced thermal analysis techniques to predict the temperature of the spacecraft's solar array for each drag pass. Odyssey telemetry data was used to correlate the thermal model. The thermal analysis was tightly coupled to the flight mechanics, aerodynamics, and atmospheric modeling efforts being performed during operations. Specifically, the thermal analysis predictions required a calculation of the spacecraft's velocity relative to the atmosphere, a prediction of the atmospheric density, and a prediction of the heat transfer coefficients due to aerodynamic heating. Temperature correlations were performed by comparing predicted temperatures of the thermocouples to the actual thermocouple readings from the spacecraft. Time histories of the spacecraft relative velocity, atmospheric density, and heat transfer coefficients, calculated using flight accelerometer and quaternion data, were used to calculate the aerodynamic heating. During aerobraking operations, the correlations were used to continually update the thermal model, thus increasing confidence in the predictions. This paper describes the thermal analysis that was performed and presents the correlations to the flight data.

  12. Exergetic analysis of parabolic trough solar thermal power plants

    Science.gov (United States)

    Petrakopoulou, F.; Ruperez, B.; San Miguel, G.

    2014-12-01

    A very important component to achieve sustainable development in the energy sector is the improvement of energy efficiency of widely applied thermodynamic processes. Evaluation and optimization methods of energy processes play a crucial role in fulfilling this goal. A suitable method for the evaluation and optimization of energy conversion systems has been proven to be the exergetic analysis. In this work, two parabolic trough solar thermal power plants are simulated in detail using commercial software, and they are further analysed and compared using an exergetic analysis. The first plant uses a thermal fluid to produce the steam required in a steam generator, while the second one produces the steam directly in the solar field. The analysis involves the evaluation of the individual components of the power plants, as well as the performance evaluation of the overall structures. The main goal is to detect thermodynamic inefficiencies of the two different configurations and propose measures to minimize those. We find that the two examined plants have similar main sources of exergy destruction: the solar field (parabolic trough solar collectors), followed by the steam generator. This reveals the importance of an optimal design of these particular components, which could reduce inefficiencies present in the system. The differences in the exergy destruction and exergetic efficiencies of individual components of the two plants are analyzed in detail based on comparable operational conditions.

  13. Solar Thermal Energy Storage in a Photochromic Macrocycle.

    Science.gov (United States)

    Vlasceanu, Alexandru; Broman, Søren L; Hansen, Anne S; Skov, Anders B; Cacciarini, Martina; Kadziola, Anders; Kjaergaard, Henrik G; Mikkelsen, Kurt V; Nielsen, Mogens Brøndsted

    2016-07-25

    The conversion and efficient storage of solar energy is recognized to hold significant potential with regard to future energy solutions. Molecular solar thermal batteries based on photochromic systems exemplify one possible technology able to harness and apply this potential. Herein is described the synthesis of a macrocycle based on a dimer of the dihydroazulene/vinylheptafulvene (DHA/VHF) photo/thermal couple. By taking advantage of conformational strain, this DHA-DHA macrocycle presents an improved ability to absorb and store incident light energy in chemical bonds (VHF-VHF). A stepwise energy release over two sequential ring-closing reactions (VHF→DHA) combines the advantages of an initially fast discharge, hypothetically addressing immediate energy consumption needs, followed by a slow process for consistent, long-term use. This exemplifies another step forward in the molecular engineering and design of functional organic materials towards solar thermal energy storage and release. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  14. Local Temperature Distribution on the Spacecraft Surface under Uneven Solar Radiation

    Directory of Open Access Journals (Sweden)

    V. S. Zarubin

    2015-01-01

    Full Text Available Solar radiation is the main factor to determine the thermal state of a spacecraft (SC when it moves to the sunlit portion of the Earth orbit and moves away from the Earth. The extent of the solar radiation impact on the SC temperature state depends, primarily, on the interaction of this radiation with the surface portions of the SA body and the design elements that are placed outside the main body. To ensure the required SC temperature surfaces are used various coating and screen-vacuum thermal insulation, as well as multilayer optical solar reflectors with a thickness being in the range from tenths of a millimeter to 15 − 20 mm.When designing the SC, to predict their temperature state at various stages of operation are used mathematical models of various levels of complexity, including models related to the solution of inverse problems for determining the conditions of the thermal effects on the SC and thermal properties of structural thermal protection materials. In most famous works, which analyse the SC temperature and condition, a mathematical model is based on the heat balance equation composed for the SC discrete circuits and containing discrete temperature values of individual functional units, structural elements and parts of the surface.This work is aimed at defining the continuous local temperature distribution over the surface of a thin-walled shell of the SC with uneven solar radiation, including cases of moving boundaries between areas with different intensity of exposure. Application of an equilibrium temperature concept of the Sun-irradiated SC surface area allowed formulating and solving the nonlinear problems on calculation of the temperature state of the shell, which is perfectly thermally isolated on the inside surface and is non-evenly irradiated on the outside surface. The paper presents the calculated dependences for finding the temperature distribution of the shell in the vicinity of jump values of the equilibrium

  15. Theoretical analysis to investigate thermal performance of co-axial heat pipe solar collector

    Science.gov (United States)

    Azad, E.

    2011-12-01

    The thermal performance of co-axial heat pipe solar collector which consist of a collector 15 co-axial heat pipes surrounded by a transparent envelope and which heat a fluid flowing through the condenser tubes have been predicted using heat transfer analytical methods. The analysis considers conductive and convective losses and energy transferred to a fluid flowing through the collector condenser tubes. The thermal performances of co-axial heat pipe solar collector is developed and are used to determine the collector efficiency, which is defined as the ratio of heat taken from the water flowing in the condenser tube and the solar radiation striking the collector absorber. The theoretical water outlet temperature and efficiency are compared with experimental results and it shows good agreement between them. The main advantage of this collector is that inclination of collector does not have influence on performance of co-axial heat pipe solar collector therefore it can be positioned at any angle from horizontal to vertical. In high building where the roof area is not enough the co-axial heat pipe solar collectors can be installed on the roof as well as wall of the building. The other advantage is each heat pipe can be topologically disconnected from the manifold.

  16. Study of Using Solar Thermal Power for the Margarine Melting Heat Process.

    Science.gov (United States)

    Sharaf Eldean, Mohamed A; Soliman, A M

    2015-04-01

    The heating process of melting margarine requires a vast amount of thermal energy due to its high melting point and the size of the reservoir it is contained in. Existing methods to heat margarine have a high hourly cost of production and use fossil fuels which have been shown to have a negative impact on the environment. Thus, we perform an analytical feasibility study of using solar thermal power as an alternative energy source for the margarine melting process. In this study, the efficiency and cost effectiveness of a parabolic trough collector (PTC) solar field are compared with that of a steam boiler. Different working fluids (water vapor and Therminol-VP1 heat transfer oil (HTO)) through the solar field are also investigated. The results reveal the total hourly cost ($/h) by the conventional configuration is much greater than the solar applications regardless of the type of working fluid. Moreover, the conventional configuration causes a negative impact to the environment by increasing the amount of CO 2 , CO, and NO 2 by 117.4 kg/day, 184 kg/day, and 74.7 kg/day, respectively. Optimized period of melt and tank volume parameters at temperature differences not exceeding 25 °C are found to be 8-10 h and 100 m 3 , respectively. The solar PTC operated with water and steam as the working fluid is recommended as a vital alternative for the margarine melting heating process.

  17. Small-Scale Flat Plate Collectors for Solar Thermal Scavenging in Low Conductivity Environments

    Directory of Open Access Journals (Sweden)

    Emmanuel Ogbonnaya

    2017-01-01

    Full Text Available There is great opportunity to develop power supplies for autonomous application on the small scale. For example, remote environmental sensors may be powered through the harvesting of ambient thermal energy and heating of a thermoelectric generator. This work investigates a small-scale (centimeters solar thermal collector designed for this application. The absorber is coated with a unique selective coating and then studied in a low pressure environment to increase performance. A numerical model that is used to predict the performance of the collector plate is developed. This is validated based on benchtop testing of a fabricated collector plate in a low-pressure enclosure. Model results indicate that simulated solar input of about 800 W/m2 results in a collector plate temperature of 298 K in ambient conditions and up to 388 K in vacuum. The model also predicts the various losses in W/m2 K from the plate to the surroundings. Plate temperature is validated through the experimental work showing that the model is useful to the future design of these small-scale solar thermal energy collectors.

  18. Thermal performance optimization of a flat plate solar air heater using genetic algorithm

    Energy Technology Data Exchange (ETDEWEB)

    Varun; Siddhartha [Department of Mechanical Engineering, National Institute of Technology, Hamirpur 177 005 (H.P.) (India)

    2010-05-15

    Thermal performance of solar air heater is low and different techniques are adopted to increase the performance of solar air heaters, such as: fins, artificial roughness etc. In this paper an attempt has been done to optimize the thermal performance of flat plate solar air heater by considering the different system and operating parameters to obtain maximum thermal performance. Thermal performance is obtained for different Reynolds number, emissivity of the plate, tilt angle and number of glass plates by using genetic algorithm. (author)

  19. A thermal comparison among several beverage can solar collectors.

    Science.gov (United States)

    Peter Y.S. Chen

    1984-01-01

    Four air-heated solar collectors were built using four different configurations of aluminum beverage cans. The collectors were then tested for four consecutive seasons for their daily efficiencies. One of the collectors was also evaluated for one season for the effect of air velocity on efficiency, temperature rise, and power consumption of the collector.

  20. New combined plant with integrated solar thermal energy; Neue Kombi-Anlage mit integrierter Solarwaerme

    Energy Technology Data Exchange (ETDEWEB)

    Leithner, R.; Dobrowolski, R.; Gresch, H. [Technische Univ. Braunschweig (Germany). Inst. fuer Waerme- und Brennstofftechnik

    1998-06-01

    In California there are already 350 MW{sub e} worth of solar thermal energy plants in operation on a more or less commercial basis. In these installations thermal oil in parabolic gutters is heated from 300 C to 400 C. The thermal oil passes its thermal energy on to a water vapour circuit via a heat exchanger. The water vapour circuit can also be heated with natural gas, for instance at night when solar energy is not available. However, as yet no existing plant fulfils all three of the following requirements: its construction should entail the lowest possible investment costs and it should be able to run without solar energy and without an expensive storage system; it should have the greatest possible efficiency, especially at times when solar energy is not available (e.g. at night); at the same time, the solar thermal energy should be harvested at the lowest possible temperature so as to make expensive concentrating equipment superfluous. These seemingly contradictory demands are now met by a new concept involving a combined gas and steam plant whose operation is based on the injection of water into the compressed air rather than on a high excess of air. This water is evaporated by solar thermal energy at temperatures below 170 C according to its partial pressure. [Deutsch] Es gibt bereits ueber 350 MWe solarthermische Anlagen in Kalifornien, die mehr oder weniger kommerziell betrieben werden. Bei diesen Anlagen wird Thermaloel von 300 C auf 400 C in Parabolrinnen erhitzt. In einem Waermetauscher gibt das Thermaloel die Waerme an einen Wasserdampfkreislauf ab, der auch mit Erdgas beheizt werden kann, wenn wie z.B. nachts keine Solarwaerme verfuegbar ist. In einem weiteren Schritt wurde vorgeschlagen, das Wasser direkt zu verdampfen. Keine dieser Anlagen genuegt jedoch gleichzeitig den folgenden drei Anforderungen: Die Anlage sollte mit moeglichst niedrigen Investitionskosten gebaut und auch ohne Solarwaerme bzw. ohne aufwendigen Speicher betrieben werden koennen

  1. Ontogenetic thermal tolerance and performance of ectotherms at variable temperatures

    National Research Council Canada - National Science Library

    Cavieres, G; Bogdanovich, J. M; Bozinovic, F

    2016-01-01

    .... Additionally, in constant and variable climatic scenarios, flies shifted to the right the optimum temperature but the maximum performance decreased only in flies reared on high temperatures and high thermal variability...

  2. Potential Applications of Concentrated Solar Thermal Technologies in the Australian Minerals Processing and Extractive Metallurgical Industry

    Science.gov (United States)

    Eglinton, Thomas; Hinkley, Jim; Beath, Andrew; Dell'Amico, Mark

    2013-12-01

    The Australian minerals processing and extractive metallurgy industries are responsible for about 20% of Australia's total greenhouse gas (GHG) emissions. This article reviews the potential applications of concentrated solar thermal (CST) energy in the Australian minerals processing industry to reduce this impact. Integrating CST energy into these industries would reduce their reliance upon conventional fossil fuels and reduce GHG emissions. As CST technologies become more widely deployed and cheaper, and as fuel prices rise, CST energy will progressively become more competitive with conventional energy sources. Some of the applications identified in this article are expected to become commercially competitive provided the costs for pollution abatement and GHG mitigation are internalized. The areas of potential for CST integration identified in this study can be classed as either medium/low-temperature or high-temperature applications. The most promising medium/low-grade applications are electricity generation and low grade heating of liquids. Electricity generation with CST energy—also known as concentrated solar power—has the greatest potential to reduce GHG emissions out of all the potential applications identified because of the 24/7 dispatchability when integrated with thermal storage. High-temperature applications identified include the thermal decomposition of alumina and the calcination of limestone to lime in solar kilns, as well as the production of syngas from natural gas and carbonaceous materials for various metallurgical processes including nickel and direct reduced iron production. Hybridization and integration with thermal storage could enable CST to sustain these energy-intensive metallurgical processes continuously. High-temperature applications are the focus of this paper.

  3. Thermal Efficiency of Power Module “Boiler with Solar Collectors as Additional Heat Source” For Combined Heat Supply System

    Directory of Open Access Journals (Sweden)

    Denysova A.E.

    2015-04-01

    Full Text Available The purpose of work is to increase the efficiency of the combined heat supply system with solar collectors as additional thermal generators. In order to optimize the parameters of combined heat supply system the mathematical modeling of thermal processes in multi module solar collectors as additional thermal generators for preheating of the water for boiler have been done. The method of calculation of multi-module solar collectors working with forced circulation for various configurations of hydraulic connection of solar collector modules as the new result of our work have been proposed. The results of numerical simulation of thermal efficiency of solar heat source for boiler of combined heat supply system with the account of design features of the circuit; regime parameters of thermal generators that allow establishing rational conditions of its functioning have been worked out. The conditions of functioning that provide required temperature of heat carrier incoming to boiler and value of flow rate at which the slippage of heat carrier is not possible for different hydraulic circuits of solar modules have been established.

  4. Performance analysis of a Kalina cycle for a central receiver solar thermal power plant with direct steam generation

    DEFF Research Database (Denmark)

    Modi, Anish; Haglind, Fredrik

    2014-01-01

    without corroding the equipment by using suitable additives with the mixture. The purpose of the study reported here was to investigate if there is any benefit of using a Kalina cycle for a direct steam generation, central receiver solar thermal power plant with high live steam temperature (450 C...... direct steam generation with water/steam as both the heat transfer fluid in the solar receivers and the cycle working fluid. This enables operating the plant with higher turbine inlet temperatures. Available literature suggests that it is feasible to use ammonia-water mixtures at high temperatures......Solar thermal power plants have attracted increasing interest in the past few years - with respect to both the design of the various plant components, and extending the operation hours by employing different types of storage systems. One approach to improve the overall plant efficiency is to use...

  5. Thermal Performance Analysis of Solar Collectors Installed for Combisystem in the Apartment Building

    Science.gov (United States)

    Žandeckis, A.; Timma, L.; Blumberga, D.; Rochas, C.; Rošā, M.

    2012-01-01

    The paper focuses on the application of wood pellet and solar combisystem for space heating and hot water preparation at apartment buildings under the climate of Northern Europe. A pilot project has been implemented in the city of Sigulda (N 57° 09.410 E 024° 52.194), Latvia. The system was designed and optimised using TRNSYS - a dynamic simulation tool. The pilot project was continuously monitored. To the analysis the heat transfer fluid flow rate and the influence of the inlet temperature on the performance of solar collectors were subjected. The thermal performance of a solar collector loop was studied using a direct method. A multiple regression analysis was carried out using STATGRAPHICS Centurion 16.1.15 with the aim to identify the operational and weather parameters of the system which cause the strongest influence on the collector's performance. The parameters to be used for the system's optimisation have been evaluated.

  6. Thermal Analysis of a Solar Powered Absorption Cooling System with Fully Mixed Thermal Storage at Startup

    Directory of Open Access Journals (Sweden)

    Camelia Stanciu

    2017-01-01

    Full Text Available A simple effect one stage ammonia-water absorption cooling system fueled by solar energy is analyzed. The considered system is composed by a parabolic trough collector concentrating solar energy into a tubular receiver for heating water. This is stored in a fully mixed thermal storage tank and used in the vapor generator of the absorption cooling system. Time dependent cooling load is considered for the air conditioning of a residential two-storey house. A parametric study is performed to analyze the operation stability of the cooling system with respect to solar collector and storage tank dimensions. The results emphasized that there is a specific storage tank dimension associated to a specific solar collector dimension that could ensure the longest continuous startup operation of the cooling system when constant mass flow rates inside the system are assumed.

  7. Effect of Selective Contacts on the Thermal Stability of Perovskite Solar Cells.

    Science.gov (United States)

    Zhao, Xing; Kim, Hui-Seon; Seo, Ja-Young; Park, Nam-Gyu

    2017-03-01

    Thermal stability of CH3NH3PbI3 (MAPbI3)-based perovskite solar cells was investigated for normal structure including the mesoporous TiO2 layer and spiro-MeOTAD and the inverted structure with PCBM and NiO. MAPbI3 was found to be intrinsically stable from 85 °C to 120 °C in the absence of moisture. However, fast degradation was observed for the encapsulated device including spiro-MeOTAD upon thermal stress at 85 °C. Photoluminescence (PL) intensity and the time constant for charge separation increased with thermal exposure time, which is indicative of inhibition of charge separation from MAPbI3 into spiro-MeOTAD. A full recovery of photovoltaic performance was observed for the 85 °C-aged device after renewal with fresh spiro-MeOTAD, which clearly indicates that thermal instability of the normal structured device is mainly due to spiro-MeOTAD, and MAPbI3 is proved to be thermally stable. Spiro-MeOTAD with additives was crystallized at 85 °C due to a low glass transition temperature, and hole mobility was significantly deteriorated, which was responsible for the thermal instability. Thermal stability was significantly improved for the inverted structure with the NiO hole transporting layer, where the power conversion efficiency (PCE) was maintained at 74% of its initial PCE of 14.71% after the 80th thermal cycle (one cycle: heating at 85 °C for 2 h and cooling at 25 °C for 2 h). This work implies that the thermal stability of perovskite solar cells depends on selective contacts.

  8. Pressure and temperature development in solar heating system during stagnation

    DEFF Research Database (Denmark)

    Dragsted, Janne; Furbo, Simon; Chen, Ziqian

    2010-01-01

    This paper presents an investigation of stagnation in solar collectors and the effects it will have on the collector loop. At a laboratory test stand at the Technical University of Denmark, a pressurized solar collector loop was designed to test different numbers of collectors and different designs...... of the pipes of the solar collector loop. During the investigation the pre-pressure of the expansion vessel and system filling pressure was changed. The investigations showed that a large pressurised expansion vessel will protect the collector loop from critically high temperatures as long as the solar...

  9. Effect of simultaneous electrical and thermal treatment on the performance of bulk heterojunction organic solar cell blended with organic salt

    Energy Technology Data Exchange (ETDEWEB)

    Sabri, Nasehah Syamin; Yap, Chi Chin; Yahaya, Muhammad [School of Applied Physics, Faculty of Science and Technology, Universiti Kebangsaan Malaysia, 43600 Bangi, Selangor (Malaysia); Salleh, Muhamad Mat [Institute of Microengineering and Nanoelectronics (IMEN), Universiti Kebangsaan Malaysia, 43600 Bangi, Selangor (Malaysia)

    2013-11-27

    This work presents the influence of simultaneous electrical and thermal treatment on the performance of organic solar cell blended with organic salt. The organic solar cells were composed of indium tin oxide as anode, poly[2-methoxy-5-(2-ethylhexyloxy)-1,4-phenylenevinylene]: (6,6)-phenyl-C61 butyric acid methyl ester: tetrabutylammonium hexafluorophosphate blend as organic active layer and aluminium as cathode. The devices underwent a simultaneous fixed-voltage electrical and thermal treatment at different temperatures of 25, 50 and 75 °C. It was found that photovoltaic performance improved with the thermal treatment temperature. Accumulation of more organic salt ions in the active layer leads to broadening of p-n doped regions and hence higher built-in electric field across thin intrinsic layer. The simultaneous electrical and thermal treatment has been shown to be able to reduce the electrical treatment voltage.

  10. The influence of weather on the thermal performance of solar heating systems

    DEFF Research Database (Denmark)

    Andersen, Elsa; Furbo, Simon; Shah, Louise Jivan

    2003-01-01

    . The investigation is based on calculations with validated models. Solar heating systems with different solar collector types, heat storage volumes and solar fractions are included in the investigation. The yearly solar radiation varies with approximately 20 % in the period from 1990 until 2002. The calculations......The influence of weather on the thermal performance of solar combi systems, solar domestic hot water systems and solar heating plants is investigated. The investigation is based on weather data from the Danish Design Reference Year, DRY and weather data measured for a period from 1990 until 2002...... show that the thermal performance of the investigated systems varies due to the weather variation. The variation of the yearly thermal performance of a solar heating plant is about 40 % while the variation of the yearly thermal performance of a solar domestic hot water system is about 30...

  11. Thermal-Structural Analysis of PICA Tiles for Solar Tower Test

    Science.gov (United States)

    Agrawal, Parul; Empey, Daniel M.; Squire, Thomas H.

    2009-01-01

    Thermal protection materials used in spacecraft heatshields are subjected to severe thermal and mechanical loading environments during re-entry into earth atmosphere. In order to investigate the reliability of PICA tiles in the presence of high thermal gradients as well as mechanical loads, the authors designed and conducted solar-tower tests. This paper presents the design and analysis work for this tests series. Coupled non-linear thermal-mechanical finite element analyses was conducted to estimate in-depth temperature distribution and stress contours for various cases. The first set of analyses performed on isolated PICA tile showed that stresses generated during the tests were below the PICA allowable limit and should not lead to any catastrophic failure during the test. The tests results were consistent with analytical predictions. The temperature distribution and magnitude of the measured strains were also consistent with predicted values. The second test series is designed to test the arrayed PICA tiles with various gap-filler materials. A nonlinear contact method is used to model the complex geometry with various tiles. The analyses for these coupons predict the stress contours in PICA and inside gap fillers. Suitable mechanical loads for this architecture will be predicted, which can be applied during the test to exceed the allowable limits and demonstrate failure modes. Thermocouple and strain-gauge data obtained from the solar tower tests will be used for subsequent analyses and validation of FEM models.

  12. MEASUREMENTS OF NON-THERMAL LINE WIDTHS IN SOLAR ACTIVE REGIONS

    Energy Technology Data Exchange (ETDEWEB)

    Brooks, David H. [College of Science, George Mason University, 4400 University Drive, Fairfax, VA 22030 (United States); Warren, Harry P. [Space Science Division, Naval Research Laboratory, Washington, DC 20375 (United States)

    2016-03-20

    Spectral line widths are often observed to be larger than can be accounted for by thermal and instrumental broadening alone. This excess broadening is a key observational constraint for both nanoflare and wave dissipation models of coronal heating. Here we present a survey of non-thermal velocities measured in the high temperature loops (1–4 MK) often found in the cores of solar active regions. This survey of Hinode Extreme Ultraviolet Imaging Spectrometer (EIS) observations covers 15 non-flaring active regions that span a wide range of solar conditions. We find relatively small non-thermal velocities, with a mean value of 17.6 ± 5.3 km s{sup −1}, and no significant trend with temperature or active region magnetic flux. These measurements appear to be inconsistent with those expected from reconnection jets in the corona, chromospheric evaporation induced by coronal nanoflares, and Alfvén wave turbulence models. Furthermore, because the observed non-thermal widths are generally small, such measurements are difficult and susceptible to systematic effects.

  13. Thermal efficiency of low cost solar collectors - CSBC; Eficiencia termica de coletores solares de baixo custo - CSBC

    Energy Technology Data Exchange (ETDEWEB)

    Pereira, Renato C.; Shiota, Robson T.; Mello, Samuel F.; Assis Junior, Valdir; Bartoli, Julio R. [Universidade Estadual de Campinas (UNICAMP), SP (Brazil). Faculdade de Engenharia Quimica. Dept. de Tecnologia de Polimeros

    2006-07-01

    The thermal performance of a low cost flat panel solar collector was measured. This Low Cost Solar Collector is a novel concept for water heating using only thermoplastics materials, used on building: ceiling and tubes made of unplasticized PVC, but without transparent cover. The top side of the UPVC panel was black painted to be the solar radiation absorber surface. Prototypes were installed on two charity houses around Campinas and at the FEQ campus, being used without any trouble for one year. The thermal efficiency analysis followed ABNT NBR 10184 standard at the Green-Solar Laboratory, Brazilian Centre for Development of Solar Thermal Energy, PUC-Minas. It was measured a thermal efficiency of 67%, compared to the 75% usually found on conventional solar collectors made of copper tubes and with glass cover. (author)

  14. Azobenzene-functionalized carbon nanotubes as high-energy density solar thermal fuels.

    Science.gov (United States)

    Kolpak, Alexie M; Grossman, Jeffrey C

    2011-08-10

    Solar thermal fuels, which reversibly store solar energy in molecular bonds, are a tantalizing prospect for clean, renewable, and transportable energy conversion/storage. However, large-scale adoption requires enhanced energy storage capacity and thermal stability. Here we present a novel solar thermal fuel, composed of azobenzene-functionalized carbon nanotubes, with the volumetric energy density of Li-ion batteries. Our work also demonstrates that the inclusion of nanoscale templates is an effective strategy for design of highly cyclable, thermally stable, and energy-dense solar thermal fuels.

  15. Thermal analysis and performance optimization of a solar hot water plant with economic evaluation

    KAUST Repository

    Kim, Youngdeuk

    2012-05-01

    The main objective of this study is to optimize the long-term performance of an existing active-indirect solar hot water plant (SHWP), which supplies hot water at 65 °C for use in a flight kitchen, using a micro genetic algorithm in conjunction with a relatively detailed model of each component in the plant and solar radiation model based on the measured data. The performance of SHWP at Changi International Airport Services (CIASs), Singapore, is studied for better payback period using the monthly average hourly diffuse and beam radiations and ambient temperature data. The data input for solar radiation model is obtained from the Singapore Meteorological Service (SMS), and these data have been compared with long-term average data of NASA (surface meteorology and solar energy or SSE). The comparison shows a good agreement between the predicted and measured hourly-averaged, horizontal global radiation. The SHWP at CIAS, which comprises 1200m 2 of evacuated-tube collectors, 50m 3 water storage tanks and a gas-fired auxiliary boiler, is first analyzed using a baseline configuration, i.e., (i) the local solar insolation input, (ii) a coolant flow rate through the headers of collector based on ASHRAE standards, (iii) a thermal load demand pattern amounting to 100m 3/day, and (iv) the augmentation of water temperature by auxiliary when the supply temperature from solar tank drops below the set point. A comparison between the baseline configuration and the measured performance of CIAS plant gives reasonably good validation of the simulation code. Optimization is further carried out for the following parameters, namely; (i) total collector area of the plant, (ii) storage volume, and (iii) three daily thermal demands. These studies are performed for both the CIAS plant and a slightly modified plant where the hot water supply to the load is adjusted constant at times when the water temperature from tank may exceed the set temperature. It is found that the latter

  16. Optimum Temperature and Thermal Stability of Crude Polyphenol ...

    African Journals Online (AJOL)

    Bello & Sule: Optimum Temperature and Thermal Stability of Crude Polyphenol Oxidase from some Common Fruits. 30. DISCUSSION. Temperature is one of the factors that affect the rate of an enzyme catalyzed reaction (Martin, 2006). Optimum temperature is the temperature at which an enzyme shows its highest catalytic ...

  17. Thermal insulation and body temperature wearing a thermal swimsuit during water immersion.

    Science.gov (United States)

    Wakabayashi, Hitoshi; Hanai, Atsuko; Yokoyama, Shintaro; Nomura, Takeo

    2006-09-01

    This study evaluated the effects of a thermal swimsuit on body temperatures, thermoregulatory responses and thermal insulation during 60 min water immersion at rest. Ten healthy male subjects wearing either thermal swimsuits or normal swimsuits were immersed in water (26 degrees C or 29 degrees C). Esophageal temperature, skin temperatures and oxygen consumption were measured during the experiments. Metabolic heat production was calculated from oxygen consumption. Heat loss from skin to the water was calculated from the metabolic heat production and the change in mean body temperature during water immersion. Total insulation and tissue insulation were estimated by dividing the temperature difference between the esophagus and the water or the esophagus and the skin with heat loss from the skin. Esophageal temperature with a thermal swimsuit was higher than that with a normal swimsuit at the end of immersion in both water temperature conditions (pthermal swimsuit than with a normal swimsuit in both water temperatures (pinsulation with the thermal swimsuit was higher than that with a normal swimsuit due to insulation of the suit at both water temperatures (pinsulation was similar in all four conditions, but significantly higher with the thermal swimsuit in both water temperature conditions (pthermal swimsuit. A thermal swimsuit can increase total insulation and reduce heat loss from the skin. Therefore, subjects with thermal swimsuits can maintain higher body temperatures than with a normal swimsuit and reduce shivering thermo-genesis.

  18. SOIL TEMPERATURE MODIFICATIONS CAUSED BY SOLARIZATION IN NURSERIES

    Directory of Open Access Journals (Sweden)

    Nereu Augusto Streck

    1993-12-01

    Full Text Available Solarization effects on soil temperature were evaluated during the autumn. The increase in soil temperature caused by the use of transparent polyethylene (PE low tunnels over solarized nurseries, in subtropical central region of the Rio Grande do Sul state, Brazil, was also quantified. Treatments were: a solarization with 100µ thickness PE (T1, b solarization with 100µ thickness PE, covered with low tunnel (T2, c solarization with 50µ thickness PE (T3, d solarization with 50µ thickness PE, covered with low tunnel (T4, and e bare soil (T. The low tunnel consisted of a 100µ thickness PE and measured 0.5m height in the center of the nursery. The results showed that additional use of low tunnels have increased, on the average, 5.0ºC over the maximum temperature of the superficial layer of the soil in the solarized nurseries. In addition, it was observed several days in which the maximum temperature exceeded 45ºC.

  19. DETERMINATION OF TEMPERATURE DISTRIBUTION FOR ANNULAR FINS WITH TEMPERATURE DEPENDENT THERMAL CONDUCTIVITY BY HPM

    Directory of Open Access Journals (Sweden)

    Davood Domairry Ganji

    2011-01-01

    Full Text Available In this paper, homotopy perturbation method has been used to evaluate the temperature distribution of annular fin with temperature-dependent thermal conductivity and to determine the temperature distribution within the fin. This method is useful and practical for solving the nonlinear heat transfer equation, which is associated with variable thermal conductivity condition. The homotopy perturbation method provides an approximate analytical solution in the form of an infinite power series. The annular fin heat transfer rate with temperature-dependent thermal conductivity has been obtained as a function of thermo-geometric fin parameter and the thermal conductivity parameter describing the variation of the thermal conductivity.

  20. A note on the effect of reflected solar radiation on airborne and ground measurements in the thermal infrared

    Science.gov (United States)

    Whitehead, V. S.

    1971-01-01

    The magnitude of thermal solar radiation reflected from water surfaces is considered. It is shown both theoretically and by field observation that, for instruments with small fields of view, the reflected thermal solar radiation can contribute significantly to the measured energy. Comparison of thermal scanner data taken from aircraft at a 16 deg azimuth angle from the mirror point of the sun over the open ocean with data taken at a 164 deg anzimuth angle from the mirror point of the sun at the same angle from nadir is indicative of a difference of 2.8 K in the equivalent black body radiation temperature. Observations taken from a surface vessel into sunglint 80 deg from nadir are indicative of an equivalent black body radiation temperature that is 34 K warmer than the temperature obtained at a similar nadir angle away from the sunglint.

  1. The thermal environment of the fiber glass dome for the new solar telescope at Big Bear Solar Observatory

    Science.gov (United States)

    Verdoni, A. P.; Denker, C.; Varsik, J. R.; Shumko, S.; Nenow, J.; Coulter, R.

    2007-09-01

    The New Solar Telescope (NST) is a 1.6-meter off-axis Gregory-type telescope with an equatorial mount and an open optical support structure. To mitigate the temperature fluctuations along the exposed optical path, the effects of local/dome-related seeing have to be minimized. To accomplish this, NST will be housed in a 5/8-sphere fiberglass dome that is outfitted with 14 active vents evenly spaced around its perimeter. The 14 vents house louvers that open and close independently of one another to regulate and direct the passage of air through the dome. In January 2006, 16 thermal probes were installed throughout the dome and the temperature distribution was measured. The measurements confirmed the existence of a strong thermal gradient on the order of 5° Celsius inside the dome. In December 2006, a second set of temperature measurements were made using different louver configurations. In this study, we present the results of these measurements along with their integration into the thermal control system (ThCS) and the overall telescope control system (TCS).

  2. A dynamic model of an innovative high-temperature solar heating and cooling system

    Directory of Open Access Journals (Sweden)

    Buonomano Annamaria

    2016-01-01

    Full Text Available In this paper a new simulation model of a novel solar heating and cooling system based on innovative high temperature flat plate evacuated solar thermal collector is presented. The system configuration includes: flat-plate evacuated solar collectors, a double-stage LiBr-H2O absorption chiller, gas-fired auxiliary heater, a closed loop cooling tower, pumps, heat exchangers, storage tanks, valves, mixers and controllers. The novelty of this study lies in the utilization of flat-plate stationary solar collectors, manufactured by TVP Solar, rather than concentrating ones (typically adopted for driving double-stage absorption chillers. Such devices show ultra-high thermal efficiencies, even at very high (about 200°C operating temperatures, thanks to the high vacuum insulation. Aim of the paper is to analyse the energy and economic feasibility of such novel technology, by including it in a prototypal solar heating and cooling system. For this purpose, the solar heating and cooling system design and performance were analysed by means of a purposely developed dynamic simulation model, implemented in TRNSYS. A suitable case study is also presented. Here, the simulated plant is conceived for the space heating and cooling and the domestic hot water production of a small building, whose energy needs are fulfilled through a real installation (settled also for experimental purposes built up close to Naples (South Italy. Simulation results show that the investigated system is able to reach high thermal efficiencies and very good energy performance. Finally, the economic analysis shows results comparable to those achieved through similar renewable energy systems.

  3. 3-D Modeling of Thermal Structure in Active Regions on the Solar Surface

    Science.gov (United States)

    Mok, Y.; Lionello, R.; Mikic, Z.; Linker, J.

    2001-05-01

    The thermal structure of a magnetically active region depends on a complicated balance between plasma heating, radiative cooling and the highly anisotropic thermal conduction guided by the magnetic field. It is also affected by plasma convection if siphon flows exist as a result of dynamic imbalance of pressure gradient, gravity and magnetic force. The difficulty of the numerical simulation lies in the wide ranges of density and temperature, separated by a narrow transition region with enormous gradients. Early studies of 1-D models (Mok et. al. 1991) provide a guidance on the thermal structure along individual field lines. A slightly more advanced 2-D model (Mok and Van Hoven 1993) produces a differential emission measure that is remarkably consistent with observations on the quiet sun. Active regions, however, require a 3-D model. We have implemented the necessary thermodynamics into our 3-D MHD code for this study. By starting with a magnetogram of an active region, we first establish an overlying magnetic structure. We then compute the thermal structure in the atmosphere. One of the most poorly understood physical processes in the energy balance is the plasma heating. We have computed the thermal structure based on various heating models and will compare their resulting emission measures. Mok, Schnack, and Van Hoven, 1991, Solar Phys. 132, 95. Mok and Van Hoven, 1993, Solar Phys. 146, 5. Work supported by the Sun Earth Connection Theory Program of NASA.

  4. Solar thermal OTV - applications to reusable and expendable launch vehicles

    Energy Technology Data Exchange (ETDEWEB)

    Kessler, Thomas L. [Boeing Co., Phantom Works (United States); Frye, Patrick [Boeing Co., Rocketdyne Propulsion and Power (United States); Partch, Russ [Air Force Research Lab. (United States)

    2000-11-01

    The Solar Orbit Transfer Vehicle (SOTV) program being sponsored by the U.S. Air Force Research Laboratory (AFRL) is developing technology that will engender revolutionary benefits to satellites and orbit-to-orbit transfer systems. Solar thermal propulsion offers significant advantages for near-term expendable launch vehicles (ELVs) such as Delta IV, mid- to far-term reusable launch vehicles (RLVs) and ultimately to manned exploration of the Moon and Mars. Solar thermal propulsion uses a relatively large mirrored concentrator to focus solar energy onto a compact absorber, which is in turn heated to >2200 K. This heat can then be used in two major ways. By flowing hydrogen or another working fluid through the absorber, high efficiency thrust can be generated with 800 sec or more specific impulse (Isp), almost twice that of conventional cryogenic stages and comparable with typical solid-core nuclear thermal stages. Within a decade, advances in materials and fabrication processes hold the promise of the Isp ranging up to 1,100 sec. In addition, attached thermionic or alkali metal thermoelectric converter (AMTEC) power converters can be used to generate 20 to 100 kilowatts (kW) of electricity. The SOTV Space Experiment (SOTV-SE), planned to be flown in 2003, will demonstrate both hydrogen propulsion and thermionic power generation, including advanced lightweight deployable concentrators suitable for large-scale applications. Evolutionary geosynchronous-transfer orbit/geosynchronous-Earth orbit (GTO/GEO) payload lift capability improvements of 50% or more to the Delta IV launch vehicles could be implemented as part of the Delta IV P4I plan shortly thereafter. Beyond that, SOTV technology should allow long-term storage of stages in orbits up to GEO with tremendous manoeuvring capability, potentially 4 to 5 km/sec or more. Servicing of low-Earth orbit (LEO) and GEO assets and reusable (ROTVs) are other possible applications. Offering a combination of high Isp and high

  5. Characteristics of thermally reduced graphene oxide and applied for dye-sensitized solar cell counter electrode

    Energy Technology Data Exchange (ETDEWEB)

    Ho, Ching-Yuan, E-mail: cyho@cycu.edu.tw [Department of Mechanical Engineering, Chung Yuan Christian University, Chung-Li, Taiwan (China); Department of Chemistry, Center for Nanotechnology and Institute of Biomedical Technology, Chung Yuan Christian University, Chung-Li, Taiwan (China); Wang, Hong-Wen [Department of Chemistry, Center for Nanotechnology and Institute of Biomedical Technology, Chung Yuan Christian University, Chung-Li, Taiwan (China); Department of Chemistry, Chung Yuan Christian University, Chung-Li, Taiwan (China)

    2015-12-01

    Graphical abstract: Experimental process: (1) graphite oxidized to graphene oxide; (2) thermal reduction from graphene oxide to graphene; (3) applying to DSSC counter electrode. - Highlights: • Intercalated defects were eliminated by increasing reduction temperature of GO. • High reduction temperature of tGP has lower resistance, high the electron lifetime. • Higher thermal reduction of GO proposes electrocatalytic properties. • DSSC using tGP{sub 250} as counter electrode has energy conversion efficiency of 3.4%. - Abstract: Graphene oxide (GO) was synthesized from a flake-type of graphite powder, which was then reduced to a few layers of graphene sheets using the thermal reduction method. The surface morphology, phase crystallization, and defect states of the reduced graphene were determined from an electron microscope equipped with an energy dispersion spectrometer, X-ray diffraction, Raman spectroscopy, and infrared spectra. After graphene formation, the intercalated defects that existed in the GO were removed, and it became crystalline by observing impurity changes and d-spacing. Dye-sensitized solar cells, using reduced graphene as the counter electrode, were fabricated to evaluate the electrolyte activity and charge transport performance. The electrochemical impedance spectra showed that increasing the thermal reduction temperature could achieve faster electron transport and longer electron lifetime, and result in an energy conversion efficiency of approximately 3.4%. Compared to the Pt counter electrode, the low cost of the thermal reduction method suggests that graphene will enjoy a wide range of potential applications in the field of electronic devices.

  6. Design, simulation and optimization of a solar dish collector with spiral-coil thermal absorber

    Directory of Open Access Journals (Sweden)

    Pavlović Saša R.

    2016-01-01

    Full Text Available The efficient conversion of solar radiation into heat at high temperature levels requires the use of concentrating solar collectors. The goal of this paper is to present the optical and the thermal analysis of a parabolic dish concentrator with a spiral coil receiver. The parabolic dish reflector consists of 11 curvilinear trapezoidal reflective petals constructed by PMMA with silvered mirror layer and has a diameter of 3.8 m, while its focal distance is 2.26m. This collector is designed with commercial software SolidWorks and simulated, optically and thermally in its Flow Simulation Studio. The optical analysis proved that the ideal position of the absorber is at 2.1m from the reflector in order to maximize the optical efficiency and to create a relative uniform heat flux over the absorber. In thermal part of the analysis, the energetic efficiency was calculated approximately 65%, while the exergetic efficiency is varied from 4% to 15% according to the water inlet temperature. Moreover, other important parameters as the heat flux and temperature distribution over the absorber are presented. The pressure drop of the absorber coil is calculated at 0.07bar, an acceptable value.

  7. 3D Temperature Distribution Model Based on Thermal Infrared Image

    Directory of Open Access Journals (Sweden)

    Tong Jia

    2017-01-01

    Full Text Available This paper aims to study the construction of 3D temperature distribution reconstruction system based on binocular vision technology. Initially, a traditional calibration method cannot be directly used, because the thermal infrared camera is only sensitive to temperature. Therefore, the thermal infrared camera is calibrated separately. Belief propagation algorithm is also investigated and its smooth model is improved in terms of stereo matching to optimize mismatching rate. Finally, the 3D temperature distribution model is built based on the matching of 3D point cloud and 2D thermal infrared information. Experimental results show that the method can accurately construct the 3D temperature distribution model and has strong robustness.

  8. Assessment on Time-Varying Thermal Loading of Engineering Structures Based on a New Solar Radiation Model

    Directory of Open Access Journals (Sweden)

    Bo Chen

    2014-01-01

    Full Text Available This paper aims to carry out the condition assessment on solar radiation model and thermal loading of bridges. A modification factor is developed to change the distribution of solar intensities during a whole day. In addition, a new solar radiation model for civil engineering structures is proposed to consider the shelter effects induced by cloud, mountains, and surrounding structures. The heat transfer analysis of bridge components is conducted to calculate the temperature distributions based on the proposed new solar radiation model. By assuming that the temperature along the bridge longitudinal direction is constant, one typical bridge segment is specially studied. Fine finite element models of deck plates and corrugate sheets are constructed to examine the temperature distributions and thermal loading of bridge components. The feasibility and validity of the proposed solar radiation model are investigated through detailed numerical simulation and parametric study. The numerical results are compared with the field measurement data obtained from the long-term monitoring system of the bridge and they shows a very good agreement in terms of temperature distribution in different time instants and in different seasons. The real application verifies effectiveness and validity of the proposed solar radiation and heat transfer analysis.

  9. Optical modeling of a solar dish thermal concentrator based on square flat facets

    Directory of Open Access Journals (Sweden)

    Pavlović Saša R.

    2014-01-01

    Full Text Available Solar energy may be practically utilized directly through transformation into heat, electrical or chemical energy. We present a procedure to design a square facet concentrator for laboratory-scale research on medium-temperature thermal processes. The efficient conversion of solar radiation into heat at these temperature levels requires the use of concentrating solar collectors. Large concentrating dishes generally have a reflecting surface made up of a number of individual mirror panels (facets. Optical ray tracing is used to generate a system performance model. A square facet parabolic solar concentrator with realistic specularly surface and facet positioning accuracy will deliver up to 13.604 kW of radiative power over a 250 mm radius disk (receiver diameter located in the focal plane on the focal length of 1500mmwith average concentrating ratio exceeding 1200. The Monte Carlo ray tracing method is used for analysis of the optical performance of the concentrator and to identify the set of geometric concentrator parameters that allow for flux characteristics suitable for medium and high-temperature applications. [Projekat Ministarstva nauke Republike Srbije, br. III42006: Research and development of energy and environmentally highly effective polygeneration systems based on renewable energy resources

  10. Solar thermal plant of air tube for solar air conditioning; Planta Solar Termica de tubos de vacio para aire acondicionado solar

    Energy Technology Data Exchange (ETDEWEB)

    Bruno, J. C.; Lopez, J.; Coronas, A.

    2004-07-01

    The present implementation of refrigeration and air conditioning technologies driven by thermal solar energy is very limited although there is a great market demand for them for environmental reasons and security of energy supply. In this paper it is presented a detailed technical description of the solar plant installed at the technological Innovation Centre CREVER, and an example of a complete energy analysis of this plant working under the required conditions to be used for solar air conditioning applications. Also it is included a review of solar air conditioning systems state of the art. (Author)

  11. Novel Molten Salts Thermal Energy Storage for Concentrating Solar Power Generation

    Energy Technology Data Exchange (ETDEWEB)

    Reddy, Ramana G. [Univ. of Alabama, Tuscaloosa, AL (United States)

    2013-10-23

    The explicit UA program objective is to develop low melting point (LMP) molten salt thermal energy storage media with high thermal energy storage density for sensible heat storage systems. The novel Low Melting Point (LMP) molten salts are targeted to have the following characteristics: 1. Lower melting point (MP) compared to current salts (<222ºC) 2. Higher energy density compared to current salts (>300 MJ/m3) 3. Lower power generation cost compared to current salt In terms of lower power costs, the program target the DOE's Solar Energy Technologies Program year 2020 goal to create systems that have the potential to reduce the cost of Thermal Energy Storage (TES) to less than $15/kWh-th and achieve round trip efficiencies greater than 93%. The project has completed the experimental investigations to determine the thermo-physical, long term thermal stability properties of the LMP molten salts and also corrosion studies of stainless steel in the candidate LMP molten salts. Heat transfer and fluid dynamics modeling have been conducted to identify heat transfer geometry and relative costs for TES systems that would utilize the primary LMP molten salt candidates. The project also proposes heat transfer geometry with relevant modifications to suit the usage of our molten salts as thermal energy storage and heat transfer fluids. The essential properties of the down-selected novel LMP molten salts to be considered for thermal storage in solar energy applications were experimentally determined, including melting point, heat capacity, thermal stability, density, viscosity, thermal conductivity, vapor pressure, and corrosion resistance of SS 316. The thermodynamic modeling was conducted to determine potential high temperature stable molten salt mixtures that have thermal stability up to 1000 °C. The thermo-physical properties of select potential high temperature stable (HMP) molten salt mixtures were also experimentally determined. All the salt mixtures align with the

  12. Research on temperature control and influence of the vacuum tubes with inserted tubes solar heater

    Science.gov (United States)

    Xiao, L. X.; He, Y. T.; Hua, J. Q.

    2017-11-01

    A novel snake-shape vacuum tube with inserted tubes solar collector is designed in this paper, the heat transfer characteristics of the collector are analyzed according to its structural characteristics, and the influence of different working temperature on thermal characteristics of the collector is studied. The solar water heater prototype consisting of 14 vacuum tubes with inserted tubes is prepared, and the hot water storage control subsystem is designed by hysteresis comparison algorithm. The heat characteristic of the prototype was experimentally studied under hot water output temperature of 40-45°C, 50-55°C and 60-65°C. The daily thermal efficiency was 64%, 50% and 46%, respectively. The experimental results are basically consistent with the theoretical analysis.

  13. Low temperature surface passivation for silicon solar cells

    Energy Technology Data Exchange (ETDEWEB)

    Leguijt, C.; Loelgen, P.; Eikelboom, J.A.; Weeber, A.W.; Schuurmans, F.M.; Sinke, W.C. [Netherlands Energy Research Foundation ECN, Petten (Netherlands); Alkemade, P.F.A.; Sarro, P.M. [Delft Institute for MicroElectronics and Submicron Technology DIMES, Delft (Netherlands); Maree, C.H.M. [Department of Atomic and Interface Physics, Debye Institute, University of Utrecht, Utrecht (Netherlands); Verhoef, L.A. [R and S Renewable Energy Systems B.V., Helmond (Netherlands)

    1996-07-18

    Surface passivation at low processing temperatures becomes an important topic for cheap solar cell processing. In this study, we first give a broad overview of the state of the art in this field. Subsequently, the results of a series of mutually related experiments are given about surface passivation with direct Plasma Enhanced Chemical Vapour Deposition (PECVD) of silicon oxide (Si-oxide) and silicon nitride (Si-nitride). Results of harmonically modulated microwave reflection experiments are combined with Capacitance-Voltage measurements on Metal-Insulator-Silicon structures (CV-MIS), accelerated degradation tests and with Secondary Ion Mass Spectrometry (SIMS) and Elastic Recoil Detection (ERD) measurements of hydrogen and deuterium concentrations in the passivating layers. A large positive fixed charge density at the interface is very important for the achieved low surface recombination velocities S. The density of interface states D{sub i}t is strongly reduced by post deposition anneals. The lowest values of S are obtained with PECVD of Si-nitride. The surface passivation obtained with Si-nitride is stable under typical operating conditions for solar cells. By using deuterium as a tracer it is shown that hydrogen in the ambient of the post deposition anneal does not play a role in the passivation by Si-nitride. Finally, the results of CV-MIS measurements on deposited Si-nitride layers are used to calculate effective recombination velocities as a function of the injection level at the surface, using a model that is able to predict the surface recombination velocity S at thermally oxidized silicon surfaces. These results are not in agreement with the measured increase of S at low injection levels

  14. Spectral and Concentration Sensitivity of Multijunction Solar Cells at High Temperature: Preprint

    Energy Technology Data Exchange (ETDEWEB)

    Friedman, Daniel J.; Steiner, Myles A.; Perl, Emmett E.; Simon, John

    2017-06-14

    We model the performance of two-junction solar cells at very high temperatures of ~400 degrees C and beyond for applications such as hybrid PV/solar-thermal power production, and identify areas in which the design and performance characteristics behave significantly differently than at more conventional near-room-temperature operating conditions. We show that high-temperature operation reduces the sensitivity of the cell efficiency to spectral content, but increases the sensitivity to concentration, both of which have implications for energy yield in terrestrial PV applications. For other high-temperature applications such as near-sun space missions, our findings indicate that concentration may be a useful tool to enhance cell efficiency.

  15. High-temperature solar receiver integrated with a short-term storage system

    Science.gov (United States)

    Giovannelli, Ambra; Bashir, Muhammad Anser; Archilei, Erika Maria

    2017-06-01

    Small-Scale Concentrated Solar Power Plants could have a potential market for off-grid applications in rural contexts with limited access to the electrical grid and favorable environmental characteristics. Some Small-Scale plants have already been developed, like the 25-30 kWe Dish-Stirling engine. Other ones are under development as, for example, plants based on Parabolic Trough Collectors coupled with Organic Rankine Cycles. Furthermore, the technological progress achieved in the development of new small high-temperature solar receiver, makes possible the development of interesting systems based on Micro Gas Turbines coupled with Dish collectors. Such systems could have several advantages in terms of costs, reliability and availability if compared with Dish-Stirling plants. In addition, Dish-Micro Gas Turbine systems are expected to have higher performance than Solar Organic Rankine Cycle plants. The present work focuses the attention on some challenging aspects related to the design of small high-temperature solar receivers for Dish-Micro Gas Turbine systems. Natural fluctuations in the solar radiation can reduce system performance and damage seriously the Micro Gas Turbine. To stabilize the system operation, the solar receiver has to assure a proper thermal inertia. Therefore, a solar receiver integrated with a short-term storage system based on high-temperature phase-change materials is proposed in this paper. Steady-state and transient analyses (for thermal storage charge and discharge phases) have been carried out using the commercial CFD code Ansys-Fluent. Results are presented and discussed.

  16. Detection of comfortable temperature based on thermal events detection indoors

    Science.gov (United States)

    Szczurek, Andrzej; Maciejewska, Monika; Uchroński, Mariusz

    2017-11-01

    This work focussed on thermal comfort as the basis to control indoor conditions. Its objective is a method to determine thermal preferences of office occupants. The method is based on detection of thermal events. They occur when indoor conditions are under control of occupants. Thermal events are associated with the use of local heating/cooling sources which have user-adjustable settings. The detection is based on Fourier analysis of indoor temperature time series. The relevant data is collected by temperature sensor. We achieved thermal events recognition rate of 86 %. Conditions when indoor conditions were beyond control were detected with 95.6 % success rate. Using experimental data it was demonstrated that the method allows to reproduce key elements of temperature statistics associated with conditions when occupants are in control of thermal comfort.

  17. Interference filters for colored glazed thermal solar collectors

    Energy Technology Data Exchange (ETDEWEB)

    Schueler, A.; Roecker, C.; Scartezzini, J.-L. [Swiss Federal Institute of Technology EPFL, Laboratoire d' Energie Solaire et de Physique du Batiment LESO-PB, Lausanne (Switzerland); Boudaden, J.; Videnovic, I. R.; Ho, R. S-C.; Oelhafen, P. [Institut fuer Physik der Universitaet Basel, Basel (Switzerland)

    2003-07-01

    Glazed thermal solar collectors, typically equipped with black, optical selective absorber sheets, exhibit good energy conversion efficiency. However, the black color, and sometimes the visibility of tubes and corrugations of the metal sheets, limit the architectural integration into buildings. In order to overcome this drawback, interference filters are considered as a promising approach. Multilayered thin film stacks deposited on the cover glass can produce a colored reflection hiding the black absorber without a great loss of energy. These interference filters are designed and optimized by numerical simulation. Such coatings can be deposited by vacuum processes (e.g. magnetron sputtering) or via the SolGel method. Optical measurements, such as spectrophotometry or ellipsometry, are used to determine film thicknesses and optical constants of individual layers, and to measure color coordinates and solar transmission for the multilayer stacks. (authors)

  18. Fifth parabolic dish solar thermal power program annual review: proceedings

    Energy Technology Data Exchange (ETDEWEB)

    None

    1984-03-01

    The primary objective of the Review was to present the results of activities within the Parabolic Dish Technology and Module/Systems Development element of the Department of Energy's Solar Thermal Energy Systems Program. The Review consisted of nine technical sessions covering overall Project and Program aspects, Stirling and Brayton module development, concentrator and engine/receiver development, and associated hardware and test results to date; distributed systems operating experience; international dish development activities; and non-DOE-sponsored domestic dish activities. A panel discussion concerning business views of solar electric generation was held. These Proceedings contain the texts of presentations made at the Review, as submitted by their authors at the beginning of the Review; therefore, they may vary slightly from the actual presentations in the technical sessions.

  19. Thermal energy storage for a space solar dynamic power system

    Science.gov (United States)

    Faget, N. M.; Fraser, W. M., Jr.; Simon, W. E.

    1985-01-01

    In the past, NASA has employed solar photovoltaic devices for long-duration missions. Thus, the Skylab system has operated with a silicon photovoltaic array and a nickel-cadmium electrochemical system energy storage system. Difficulties regarding the employment of such a system for the larger power requirements of the Space Station are related to a low orbit system efficiency and the large weight of the battery. For this reason the employment of a solar dynamic power system (SDPS) has been considered. The primary components of an SDPS include a concentrating mirror, a heat receiver, a thermal energy storage (TES) system, a thermodynamic heat engine, an alternator, and a heat rejection system. The heat-engine types under consideration are a Brayton cycle engine, an organic Rankine cycle engine, and a free-piston/linear-alternator Stirling cycle engine. Attention is given to a system description, TES integration concepts, and a TES technology assessment.

  20. Multi-Use Solar Thermal System for Oxygen Production from Lunar Regolith [7227-570] Project

    Data.gov (United States)

    National Aeronautics and Space Administration — We propose to develop an innovative solar thermal system for oxygen production from lunar regolith. In this system solar radiation is collected by the concentrator...

  1. Charge and Discharge Analyses of a PCM Storage System Integrated in a High-Temperature Solar Receiver

    Directory of Open Access Journals (Sweden)

    Ambra Giovannelli

    2017-11-01

    Full Text Available Solar Dish Micro Gas Turbine (MGT systems have the potential to become interesting small-scale power plants in off-grid or mini-grid contexts for electricity or poly-generation production. The main challenging component of such systems is the solar receiver which should operate at high temperatures with concentrated solar radiations, which strongly vary with time. This paper deals with the design and the analysis of a novel solar receiver integrated with a short-term storage system based on Phase Change Materials to prevent sudden variations in the maximum temperature of the MGT working fluid. Particularly, the charge and discharge behavior of the storage system was analyzed by means of Computational Fluid Dynamic methods to evaluate the potentiality of the concept and the component capabilities. Achieved results were highly satisfactory: the novel solar receiver has a good thermal inertia and can prevent relevant fluctuations in the working fluid temperature for 20–30 min.

  2. Distillate yield improvement using a parabolic dish reflector coupled single slope basin solar still with thermal energy storage using beeswax

    Directory of Open Access Journals (Sweden)

    Aondoyila KUHE

    2016-07-01

    Full Text Available A single slope solar still, integrated with latent heat thermal energy storage system coupled to a parabolic concentrator was designed with the aim of improving productivity. 14 kg of beeswax was used as phase change material (PCM between the absorber plate and the bottom of the still to keep the operating temperature of the still high enough to produce distilled water even during the sunset hours. The bottom of the still is covered by 0.2 m aluminum sheet painted black on the side facing the parabolic concentrator to help in absorbing solar radiation reflected from the parabolic concentrator and conducting same to the PCM. To determine the effect of PCM, a solar still without PCM was used to compare with the solar still with PCM. The temperature of water, air temperature, inner surface glass temperature and outer surface glass temperature were measured. Experimental results show that the effect of thermal storage in the parabolic concentrator-coupled single slope solar still increased the productivity by 62%.

  3. Evaluation of power block arrangements for 100MW scale concentrated solar thermal power generation using top-down design

    Science.gov (United States)

    Post, Alexander; Beath, Andrew; Sauret, Emilie; Persky, Rodney

    2017-06-01

    Concentrated solar thermal power generation poses a unique situation for power block selection, in which a capital intensive heat source is subject to daily and seasonal fluctuations in intensity. In this study, a method is developed to easily evaluate the favourability of different power blocks for converting the heat supplied by a concentrated solar thermal plant into power at the 100MWe scale based on several key parameters. The method is then applied to a range of commercially available power cycles that operate over different temperatures and efficiencies, and with differing capital costs, each with performance and economic parameters selected to be typical of their technology type, as reported in literature. Using this method, the power cycle is identified among those examined that is most likely to result in a minimum levelised cost of energy of a solar thermal plant.

  4. Thermal instabilities in magnetically confined plasmas - Solar coronal loops

    Science.gov (United States)

    Habbal, S. R.; Rosner, R.

    1979-01-01

    The thermal stability of confined solar coronal structures ('loops') is investigated, following both normal mode and a new, global instability analysis. It is demonstrated that: (1) normal mode analysis shows modes with size scales comparable to that of loops to be unstable, but to be strongly affected by the loop boundary conditions; (2) a global analysis, based upon variation of the total loop energy losses and gains, yields loop stability conditions for global modes dependent upon the coronal loop heating process, with magnetically coupled heating processes giving marginal stability. The connection between the present analysis and the minimum flux corona of Hearn is also discussed.

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

    Energy Technology Data Exchange (ETDEWEB)

    Ballot, E. [ALTER Alsace (France)

    2004-01-01

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

  6. Solar-thermal-energy collection/storage-pond system

    Science.gov (United States)

    Blahnik, D.E.

    1982-03-25

    A solar thermal energy collection and storage system is disclosed. Water is contained, and the water surface is exposed directly to the sun. The central part of an impermeable membrane is positioned below the water's surface and above its bottom with a first side of the membrane pointing generally upward in its central portion. The perimeter part of the membrane is placed to create a watertight boundary separating the water into a first volume which is directly exposable to the sun and which touches the membranes first side, and a second volumn which touches the membranes second side. A salt is dissolved in the first water volume.

  7. Evaluation of thermal and photovoltaic solar systems in agricultural production units, Northern Huetar Region, Costa Rica

    Directory of Open Access Journals (Sweden)

    Tomás de Jesús Guzmán Hernández

    2017-09-01

    Full Text Available The dependence on fossil fuels urges society to seek for clean energy alternatives, in order to mitigate the effects of climate change. The objective of this study was to determine the potential of solar energy used for water heating and electricity generation. The study was conducted at the dairy of the Technology Institute of Costa Rica, San Carlos Headquarter, from May 15 to April 2016. The data related to the amount of the electricity produced and the temperature reached by water was obtained from the installed photovoltaic and thermal systems, the data was recorded by a computerized register. The obtained information about electricity production allowed researchers to calculate the amount of carbon dioxide equivalent that was not emitted into the atmosphere, and also the acquired economic saving on consumption. The use of these systems allowed the production unit have a self- sufficient source of electrical energy percentage, actually around 30 to 40% of the total electrical consumption. According to the energy production, the solar thermal system was capable to increase water temperature between 20 to 37 °C, temperature that represents more than 70% of the energy needed in order to reach the required water temperature (70 °C for cleaning and sanitizing the milking equipment, and also an economical saving around $90 per month was achieved. The results showed that these systems allow to improve the economical and productive efficiency of agricultural production units in the Northern Huetar Region of Costa Rica.

  8. A Selective Metasurface Absorber with An Amorphous Carbon Interlayer for Solar Thermal Applications

    CERN Document Server

    Wan, Chenglong; Nunez-Sanchez, S; Chen, Lifeng; Lopez-Garcia, M; Pugh, J; Zhu, Bofeng; Selvaraj, P; Mallick, T; Senthilarasu, S; Cryan, M J

    2016-01-01

    This paper presents fabrication, measurement and modelling results for a metal-dielectric-metal metasurface absorber for solar thermal applications. The structure uses amorphous carbon as an inter-layer between thin gold films with the upper film patterned with a 2D periodic array using focused ion beam etching. The patterned has been optimised to give high absorptance from 400-1200nm and low absorptance above this wavelength range to minimise thermal radiation and hence obtain higher temperature performance. Wide angle absorptance results are shown and detailed modelling of a realistic nanostructured upper layer results in excellent agreement between measured and modelled results. The use of gold in this paper is a first step towards a high temperature metasurface where gold can be replaced by other refractory metals such as tungsten or chrome.

  9. Architectonic integration of solar thermal facilities; Integracion arquitectonica de instalaciones de energia solar termica

    Energy Technology Data Exchange (ETDEWEB)

    Lopez, G.; Martinez, J.

    2004-07-01

    This article proposes a procedure to achieve an appropriate architectural integration of a solar thermal system on a building taking into account urban planning, building typology, installation and construction factors that take part in the process of integration. Sun exposure of solar collectors is the main determinant since it affects directly to the design of the skin of the building. An appropriate analysis and resolution of the incorporation of the solar system in the 4 levels is arise in order to assure a correct integration of the system in the building. Starting from urban planning determining factors, a rational process of integration on the basis of the characteristics of the system, of the building and of its interrelation should guarantee an appropriate solution. (Author)

  10. Bionics in textiles: flexible and translucent thermal insulations for solar thermal applications.

    Science.gov (United States)

    Stegmaier, Thomas; Linke, Michael; Planck, Heinrich

    2009-05-13

    Solar thermal collectors used at present consist of rigid and heavy materials, which are the reasons for their immobility. Based on the solar function of polar bear fur and skin, new collector systems are in development, which are flexible and mobile. The developed transparent heat insulation material consists of a spacer textile based on translucent polymer fibres coated with transparent silicone rubber. For incident light of the visible spectrum the system is translucent, but impermeable for ultraviolet radiation. Owing to its structure it shows a reduced heat loss by convection. Heat loss by the emission of long-wave radiation can be prevented by a suitable low-emission coating. Suitable treatment of the silicone surface protects it against soiling. In combination with further insulation materials and flow systems, complete flexible solar collector systems are in development.

  11. Fuzzy Approximate Model for Distributed Thermal Solar Collectors Control

    KAUST Repository

    Elmetennani, Shahrazed

    2014-07-01

    This paper deals with the problem of controlling concentrated solar collectors where the objective consists of making the outlet temperature of the collector tracking a desired reference. The performance of the novel approximate model based on fuzzy theory, which has been introduced by the authors in [1], is evaluated comparing to other methods in the literature. The proposed approximation is a low order state representation derived from the physical distributed model. It reproduces the temperature transfer dynamics through the collectors accurately and allows the simplification of the control design. Simulation results show interesting performance of the proposed controller.

  12. Thermal Emissivity and Cigarette Coal Temperature During Smolder

    Directory of Open Access Journals (Sweden)

    Lyman CS

    2014-12-01

    Full Text Available Coal temperatures affect the burn properties of cigarettes. Thermal imaging was used to determine the average maximum surface coal temperatures during smolder of cigarettes of different tobacco types. The thermal imaging camera was calibrated against a reference blackbody. An emissivity correction was necessary since the set point temperatures of the reference blackbody did not correspond to the measured temperatures of the reference blackbody. A 0.87 camera emissivity was applied to provide accurate coal temperatures at a corrected emissivity of approximately 1. The average maximum surface coal temperatures during smolder of unfiltered single-tobacco-type cigarettes and a commercial blend cigarette were determined (with the camera lens focused parallel to the cigarette, and no discernible differences among them were found. The calculated average maximum surface coal temperature during smolder for all cigarettes was 584 AA± 15 °C. During smolder, thermocouples were used to measure the temperature of the gas phase (along the central axis of coal, and the thermal imaging camera was used to measure the temperature of the solid phase of the coal's surface. Using thermocouples, the peak coal temperatures in the center of the coal during smolder for three filtered single-tobacco-type cigarettes were 736-744 °C. Peak coal temperatures, measured by thermal imaging, on the surface of the coal (with the camera lens focused coaxially with the coal and the ash removed for the same three single-tobacco-type cigarettes had a range of 721-748 °C. There was good correspondence between the two techniques. These results confirm that during smolder the gas-phase temperature inside the coal (as measured with the thermocouple and the solid-phase temperatures beneath the ash (as measured with the camera are in near thermal equilibrium. With proper calibration, a thermal imaging system is a good alternative to thermocouples for measuring cigarette coal

  13. Investigation of small scale solar concentration parabolic dish with heat storage: (low to medium temperature application

    Energy Technology Data Exchange (ETDEWEB)

    Madessa, Habtamu Bayera

    2012-07-01

    This PhD thesis focuses on the development and testing of a small scale concentrating parabolic dish with heat storage for low to medium temperature applications. The system consists of a parabolic dish solar concentrator that concentrates solar radiation, a fibrous mat solar absorber that captures concentrated solar rays and converts them to thermal energy and a packed bed with pebble rock as a thermal energy storage unit. This research has targeted several issues in which there is a lack of knowledge on small scale concentrating solar energy technologies, with the work summarized in eight papers. Paper 1 concerns experimental measurement of the dynamic temperature profiles along a rock bed heat storage unit during thermal charging and degradation. The study examined both finned and non-finned types of rock bed storages. The effects of the long fins. which are incorporated to transport heat from the bottom to the top surface of the heat storage, were investigated in relation to temperature distribution. As an extension of Paper 1, the performance of a rock bed fitted with long fins was studied as a heat storage unit and a cooking device. The bed charging efficiency, as well as the capacity to store thermal energy and extract heat for boiling of water was discussed. Paper 3 describes the implemention of a 1D numerical model in the MATLAB environment to simulate the transient temperature profiles of rock bed heat storage units. Conservation equations were formulated for the air, rock pebble and fins. The equations were solved on a staggered grid, and the model predicts the experimental results reasonably well. The thesis also investigates two types of volumetric solar absorbers (a fibrous wire mesh and a ceramic) that could be incorporated with a small scale solar concentrating parabolic dish system. Both the fibrous mesh and ceramic type absorbers display a better performance, as discussed in Paper 4. Another contribution of the PhD work is to investigate a 1D sun

  14. Fluid temperatures: Modeling the thermal regime of a river network

    Science.gov (United States)

    Rhonda Mazza; Ashley Steel

    2017-01-01

    Water temperature drives the complex food web of a river network. Aquatic organisms hatch, feed, and reproduce in thermal niches within the tributaries and mainstem that comprise the river network. Changes in water temperature can synchronize or asynchronize the timing of their life stages throughout the year. The water temperature fluctuates over time and place,...

  15. Thermal Treatment of Mercury Mine Wastes Using a Rotary Solar Kiln

    Directory of Open Access Journals (Sweden)

    Andrés Navarro

    2014-01-01

    Full Text Available Thermal desorption, by a rotary kiln of mercury contaminated soil and mine wastes, has been used in order to volatilize mercury from the contaminated medium. Solar thermal desorption is an innovative treatment that uses solar energy to increase the volatility of contaminants, which are removed from a solid matrix by a controlled air flow system. Samples of soils and mine wastes used in the experiments were collected in the abandoned Valle del Azogue mine (SE, Spain, where a complex ore, composed mainly of cinnabar, arsenic minerals (realgar and orpiment and stibnite, was mined. The results showed that thermal treatment at temperatures >400 °C successfully lowered the Hg content (2070–116 ppm to <15 mg kg−1. The lowest values of mercury in treated samples were obtained at a higher temperature and exposition time. The samples that showed a high removal efficiency (>99% were associated with the presence of significant contents of cinnabar and an equivalent diameter above 0.8 mm.

  16. Recycling of hazardous solid waste material using high-temperature solar process heat

    Energy Technology Data Exchange (ETDEWEB)

    Schaffner, B.; Meier, A.; Wuillemin, D.; Hoffelner, W.; Steinfeld, A.

    2003-03-01

    A novel high-temperature solar chemical reactor is proposed for the thermal recycling of hazardous solid waste material using concentrated solar power. A 10 kW solar reactor prototype was designed and tested for the carbothermic reduction of electric arc furnace dusts (EAFD). The reactor was subjected to mean solar flux intensities of 2000 kW/m2 and operated in both batch and continuous mode within the temperature range 1120-1400 K. Extraction of up to 99% and 90% of the Zn originally contained in the EAFD was achieved in the residue for the batch and continuous solar experiments, respectively. The condensed off-gas products consisted mainly of Zn, Pb, and Cl. No ZnO was detected when the O{sub 2} concentration remained below 2 vol.-%. The use of concentrated solar energy as the source of process heat offers the possibility of converting hazardous solid waste material into valuable commodities for processes in closed and sustainable material cycles. (author)

  17. Autonomous low-temperature solar Rankine cycle system for reverse osmosis desalination

    Energy Technology Data Exchange (ETDEWEB)

    Manolakos, D.; Makris, G.; Papadakis, G.; Kyritsis, S. [Agricultural University of Athens (Greece). Dept. of Agricultural Engineering; Bouzianas, K. [Hellas Energy K. Bouzianas P. Moschovitis and Co., Athens (Greece)

    2004-07-01

    The research regards the development, application testing and performance evaluation of a low temperature solar organic Rankine cycle system for Reverse Osmosis (RO) desalination. Below is given a technical description of the system under development: Thermal energy produced by the solar array evaporates the working fluid (HFC- 134a) in the evaporator surface. The super-heated vapour is driven to the expanders where the generated mechanical work produced by the Rankine cycle drives the RO unit pumps (high pressure pump, cooling water pump, feed water pump) and circulating pump. The saturated vapour at the expanders' outlet is directed to the condenser and condensates. On the condenser surface, seawater is pre-heated and directed to the seawater reservoir. Seawater pre-heating is applied to increase the fresh water recovery ratio. The seawater tank is insulated. The use of seawater on the condenser surface decreases the temperature of ''Low Temperature Reservoir'' of Rankine cycle thus a better cycle efficiency is achieved. For the prototype system 240 m2 of vacuum tube solar collectors will be deployed. The evaporator and condenser capacity is estimated to be about 100 kW. For these systems' characteristics and considering a water recovery ratio of seawater RO desalination unit of 30%, the average yearly fresh water production is estimated at 1450 m3 (or 4 m3 daily). Specific innovations of the system are: Low temperature thermal sources can be exploited efficiently for fresh water production; solar energy is used indirectly and does not heat the seawater; the RO unit is driven by mechanical work produced from the process; the system condenser acts as sea water pre-heater and this serves a double purpose; (1) increase of feed water temperature implies higher fresh water production (2) decrease of temperature of ''low temperature reservoir'' of Rankine cycle implies higher cycle efficiencies. (orig.)

  18. Mathematical model for solar drying of potato cylinders with thermal conductivity radially modulated

    Science.gov (United States)

    Trujillo Arredondo, Mariana

    2014-05-01

    A mathematical model for drying potato cylinders using solar radiation is proposed and solved analytically. The model incorporates the energy balance for the heat capacity of the potato, the radiation heat transfer from the potato toward the drying chamber and the solar radiation absorbed by the potato during the drying process. Potato cylinders are assumed to exhibit a thermal conductivity which is radially modulated. The method of the Laplace transform, with integral Bromwich and residue theorem will be applied and the analytic solutions for the temperature profiles in the potato cylinder will be derived in the form of an infinite series of Bessel functions, when the thermal conductivity is constant; and in the form of an infinite series of Heun functions, when the thermal conductivity has a linear radial modulation. All computations are performed using computer algebra, specifically Maple. It is expected that the analytical results obtained will be useful in food engineering and industry. Our results suggest some lines for future investigations such as the adoption of more general forms of radial modulation for the thermal conductivity of potato cylinders; and possible applications of other computer algebra software such as Maxima and Mathematica.

  19. Study of the stagnation in a thermal solar installation. Influence of the design of the hydraulic circuit; Estudio del estancamiento en una instalacion solar termica. Influencia del diseno del circuito hidraulico

    Energy Technology Data Exchange (ETDEWEB)

    Vicente, P. G.

    2008-07-01

    An experimental study of stagnation in a solar thermal facility has been carried-out. The experimental facility consists of 4 flat solar collectors of 2 m{sup 2} each one and a tank of 450 litres. It has been determined the evolution over time in temperature in 20 points in the hydraulic circuit. These data, together with pressure and flow measurements, permit to show the actual behaviour of the solar system at stagnation conditions. (Author)

  20. Solar selective absorber coating for high service temperatures, produced by plasma sputtering

    Science.gov (United States)

    Lanxner, Michael; Elgat, Zvi

    1990-08-01

    Spectrally selective absorber coatings, deposited on engineering material substrates such as stainless steel, have been developed for service as efficient solar photothermal energy converters. The selective solar absorber is based on a multilayer of thin films, produced by sputtering. The main solar absorber is a metal/ceramic (cermet) composite, such as, Mo/Al2th or Mo/Si02, with a graded metal concentration. Such a cermet layer, strongly absorbs radiation over most of the range of the solar spectrum but is transparent to longer wavelength radiation. The cermet layer is deposited on a highly reflecting infrared metal layer. Two more layers were added: An AhO diffusion barrier layer which is deposited first on the substrate and an AI2O or a Si02 antireflection layer which is deposited on the top of the cermet film. In order to better understand the spectral reflectivity of the multilayered selective coating, a procedure for the calculation of the optical properties was developed. After the R&D development phase was successfully completed, a full scale production coating machine was constructed. The production machine is a linear in line coater. The selective coating is deposited on stainless steel tubes, translating in the coating machine while rotating about their axes, along their axial direction. Measurements of reflectance, solar absorptivity, a, thermal emissivity, C, and high temperature durability, are all parts of the quality control routine. The results show values of a in the range 0.96 - 0.98. The thermal emissivity at 350CC is in the range 0.16 - 0.18. Thermal durability tests, show no degradation of the coating when subjected to up to 65O in vacuum for one month and when passed through a temperature cycling test which includes 1200 cycles between temperatures of 150CC and 450CCfor a period of two months.

  1. Thermal Stability-Enhanced and High-Efficiency Planar Perovskite Solar Cells with Interface Passivation.

    Science.gov (United States)

    Zhang, Weihai; Xiong, Juan; Jiang, Li; Wang, Jianying; Mei, Tao; Wang, Xianbao; Gu, Haoshuang; Daoud, Walid A; Li, Jinhua

    2017-11-08

    As the electron transport layer (ETL) of perovskite solar cells, oxide semiconductor zinc oxide (ZnO) has been attracting great attention due to its relatively high mobility, optical transparency, low-temperature fabrication, and good environment stability. However, the nature of ZnO will react with the patron on methylamine, which would deteriorate the performance of cells. Although many methods, including high-temperature annealing, doping, and surface modification, have been studied to improve the efficiency and stability of perovskite solar cells with ZnO ETL, devices remain relatively low in efficiency and stability. Herein, we adopted a novel multistep annealing method to deposit a porous PbI 2 film and improved the quality and uniformity of perovskite films. The cells with ZnO ETL were fabricated at the temperature of <150 °C by solution processing. The power conversion efficiency (PCE) of the device fabricated by the novel annealing method increased from 15.5 to 17.5%. To enhance the thermal stability of CH 3 NH 3 PbI 3 (MAPbI 3 ) on the ZnO surface, a thin layer of small molecule [6,6]-phenyl-C 61 -butyric acid methyl ester (PCBM) was inserted between the ZnO layer and perovskite film. Interestingly, the PCE of PCBM-passivated cells could reach nearly 19.1%. To our best knowledge, this is the highest PCE value of ZnO-based perovskite solar cells until now. More importantly, PCBM modification could effectively suppress the decomposition of MAPbI 3 and improve the thermal stability of cells. Therefore, the ZnO is a promising candidate of electron transport material for perovskite solar cells in future applications.

  2. Identification and analysis of factors affecting thermal shock resistance of ceramic materials in solar receivers

    Science.gov (United States)

    Hasselman, D. P. H.; Singh, J. P.; Satyamurthy, K.

    1980-01-01

    An analysis was conducted of the possible modes of thermal stress failure of brittle ceramics for potential use in point-focussing solar receivers. The pertinent materials properties which control thermal stress resistance were identified for conditions of steady-state and transient heat flow, convective and radiative heat transfer, thermal buckling and thermal fatigue as well as catastrophic crack propagation. Selection rules for materials with optimum thermal stress resistance for a particular thermal environment were identified. Recommendations for materials for particular components were made. The general requirements for a thermal shock testing program quantitatively meaningful for point-focussing solar receivers were outlined. Recommendations for follow-on theoretical analyses were made.

  3. Microscale solid-state thermal diodes enabling ambient temperature thermal circuits for energy applications

    KAUST Repository

    Wang, Song

    2017-05-10

    Thermal diodes, or devices that transport thermal energy asymmetrically, analogous to electrical diodes, hold promise for thermal energy harvesting and conservation, as well as for phononics or information processing. The junction of a phase change material and phase invariant material can form a thermal diode; however, there are limited constituent materials available for a given target temperature, particularly near ambient. In this work, we demonstrate that a micro and nanoporous polystyrene foam can house a paraffin-based phase change material, fused to PMMA, to produce mechanically robust, solid-state thermal diodes capable of ambient operation with Young\\'s moduli larger than 11.5 MPa and 55.2 MPa above and below the melting transition point, respectively. Moreover, the composites show significant changes in thermal conductivity above and below the melting point of the constituent paraffin and rectification that is well-described by our previous theory and the Maxwell–Eucken model. Maximum thermal rectifications range from 1.18 to 1.34. We show that such devices perform reliably enough to operate in thermal diode bridges, dynamic thermal circuits capable of transforming oscillating temperature inputs into single polarity temperature differences – analogous to an electrical diode bridge with widespread implications for transient thermal energy harvesting and conservation. Overall, our approach yields mechanically robust, solid-state thermal diodes capable of engineering design from a mathematical model of phase change and thermal transport, with implications for energy harvesting.

  4. Temperature-dependent thermal properties of ex vivo liver undergoing thermal ablation.

    Science.gov (United States)

    Guntur, Sitaramanjaneya Reddy; Lee, Kang Il; Paeng, Dong-Guk; Coleman, Andrew John; Choi, Min Joo

    2013-10-01

    Thermotherapy uses a heat source that raises temperatures in the target tissue, and the temperature rise depends on the thermal properties of the tissue. Little is known about the temperature-dependent thermal properties of tissue, which prevents us from accurately predicting the temperature distribution of the target tissue undergoing thermotherapy. The present study reports the key thermal parameters (specific heat capacity, thermal conductivity and heat diffusivity) measured in ex vivo porcine liver while being heated from 20 ° C to 90 ° C and then naturally cooled down to 20 ° C. The study indicates that as the tissue was heated, all the thermal parameters resulted in plots with asymmetric quasi-parabolic curves with temperature, being convex downward with their minima at the turning temperature of 35-40 ° C. The largest change was observed for thermal conductivity, which decreased by 9.6% from its initial value (at 20 ° C) at the turning temperature (35 ° C) and rose by 45% at 90 ° C from its minimum (at 35 ° C). The minima were 3.567 mJ/(m(3) ∙ K) for specific heat capacity, 0.520 W/(m.K) for thermal conductivity and 0.141 mm(2)/s for thermal diffusivity. The minimum at the turning temperature was unique, and it is suggested that it be taken as a characteristic value of the thermal parameter of the tissue. On the other hand, the thermal parameters were insensitive to temperature and remained almost unchanged when the tissue cooled down, indicating that their variations with temperature were irreversible. The rate of the irreversible rise at 35 ° C was 18% in specific heat capacity, 40% in thermal conductivity and 38.3% in thermal diffusivity. The study indicates that the key thermal parameters of ex vivo porcine liver vary largely with temperature when heated, as described by asymmetric quasi-parabolic curves of the thermal parameters with temperature, and therefore, substantial influence on the temperature distribution of the tissue undergoing

  5. High temperature solar energy absorbing surfaces

    Science.gov (United States)

    Schreyer, J.M.; Schmitt, C.R.; Abbatiello, L.A.

    A solar collector having an improved coating is provided. The coating is a plasma-sprayed coating comprising a material having a melting point above 500/sup 0/C at which it is stable and selected from the group of boron carbide, boron nitride, metals and metal oxides, nitrides, carbides, borides, and silicates. The coatings preferably have a porosity of about 15 to 25% and a thickness of less than 200 micrometers. The coatings can be provided by plasma-spraying particles having a mean diameter of about 10 to 200 micrometers.

  6. Thermal performance of Danish solar combi systems in practice and in theory

    DEFF Research Database (Denmark)

    Andersen, Elsa; Shah, Louise Jivan; Furbo, Simon

    2004-01-01

    An overview of measured thermal performances of Danish solar combi systems in practice is given. The thermal performance varies greatly from system to system. Measured and calculated thermal performances of different solar combi systems are compared and the main reasons for the different thermal...... performances are given. Further, a parametric study on two solar combi system types is performed. Based on the investigation it can be concluded that the thermal performance first of all is influenced by the space heating consumption during the summer period and that the systems in practice perform...

  7. Storage of low grade solar thermal energy by adsorption of organics

    Science.gov (United States)

    Kohler, Tobias; Müller, Karsten

    2017-06-01

    In this work the efficiency of new systems for adsorptive energy storage for low grade solar thermal energy is evaluated. They are based on different adsorption systems with alcohols as adsorbates on activated carbon as adsorbent. They showed superior storage characteristics compared to the reference working pair water / zeolite 13X. The maximum efficiencies of the systems methanol and ethanol on activated carbon lie in the same range as the efficiency of the reference pair, but are reached at lower regeneration temperatures. Therefore, these systems are perfectly suited for the storage of low grad heat from collector types like the flat-plate collector or vacuum-collectors.

  8. Expanding thermal plasma chemical vapour deposition of ZnO:Al layers for CIGS solar cells

    OpenAIRE

    Sharma, K; Williams, B. L.; Mittal, A.; Knoops, H. C. M.; Kniknie, B.J.; Bakker, N J; Kessels, W. M. M.; Schropp, R.E.I.; Creatore, M.

    2014-01-01

    Aluminium-doped zinc oxide (ZnO:Al) grown by expanding thermal plasma chemical vapour deposition (ETP-CVD) has demonstrated excellent electrical and optical properties, which make it an attractive candidate as a transparent conductive oxide for photovoltaic applications. However, when depositing ZnO:Al on CIGS solar cell stacks, one should be aware that high substrate temperature processing (i.e., >200°C) can damage the crucial underlying layers/interfaces (such as CIGS/CdS and CdS/i-ZnO). In...

  9. Impact of size and temperature on thermal expansion of nanomaterials

    Indian Academy of Sciences (India)

    Abstract. A theoretical method has been discussed to study the size dependency of thermal expan- sion of nanomaterials at higher temperature by considering the surface effect. A thermodynamical analysis of the equation of state (EoS) is studied from the knowledge of thermal expansion of nano- materials based on ...

  10. Impact of size and temperature on thermal expansion of nanomaterials

    Indian Academy of Sciences (India)

    A theoretical method has been discussed to study the size dependency of thermal expansion of nanomaterials at higher temperature by considering the surface effect. A thermodynamical analysis of the equation of state (EoS) is studied from the knowledge of thermal expansion of nano-materials based on theoretical ...

  11. Temperature dependence of thermal conductivity of vanadium ...

    Indian Academy of Sciences (India)

    Unknown

    . Cryogenic Engineering .... Thermal conductivity of vanadium substituted BPSCCO system. 441 trical resistivity as well as the small decrease ..... G, Marre D, Putti M and Siri A S 1997 Physica C273 314. Chawlek J M, Uher C, Whitaker J F and ...

  12. Thermal degradation kinetics and solid state, temperature ...

    Indian Academy of Sciences (India)

    WINTEC

    Phenothiazine derivatives belong to a big group of aromatic compounds. These derivatives are substituted in ... Elemental analysis for carbon, hydrogen, nitrogen and sulphur were done using Vario EL III CHNS ... The aim of the kinetic study of thermal analysis data is to find out the most probable kinetic model which best ...

  13. Design of Particle-Based Thermal Energy Storage for a Concentrating Solar Power System

    Energy Technology Data Exchange (ETDEWEB)

    Ma, Zhiwen [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Zhang, Ruichong [Colorado School of Mines; Sawaged, Fadi [Colorado School of Mines

    2017-06-03

    Solid particles can operate at higher temperature than current molten salt or oil, and they can be a heat-transfer and storage medium in a concentrating solar power (CSP) system. By using inexpensive solid particles and containment material for thermal energy storage (TES), the particle-TES cost can be significantly lower than other TES methods such as a nitrate-salt system. The particle-TES system can hold hot particles at more than 800 degrees C with high thermal performance. The high particle temperatures increase the temperature difference between the hot and cold particles, and they improve the TES capacity. The particle-based CSP system is able to support high-efficiency power generation, such as the supercritical carbon-dioxide Brayton power cycle, to achieve >50% thermal-electric conversion efficiency. This paper describes a solid particle-TES system that integrates into a CSP plant. The hot particles discharge to a heat exchanger to drive the power cycle. The returning cold particles circulate through a particle receiver to absorb solar heat and charge the TES. This paper shows the design of a particle-TES system including containment silos, foundation, silo insulation, and particle materials. The analysis provides results for four TES capacities and two silo configurations. The design analysis indicates that the system can achieve high thermal efficiency, storage effectiveness (i.e., percentage usage of the hot particles), and exergetic efficiency. An insulation method for the hot silo was considered. The particle-TES system can achieve high performance and low cost, and it holds potential for next-generation CSP technology.

  14. The Electron Temperature and Anisotropy in the Solar Wind. Comparison of the Core and Halo Populations

    Science.gov (United States)

    Pierrard, V.; Lazar, M.; Poedts, S.; Štverák, Š.; Maksimovic, M.; Trávníček, P. M.

    2016-08-01

    Estimating the temperature of solar wind particles and their anisotropies is particularly important for understanding the origin of their deviations from thermal equilibrium and the effects this has. In the absence of energetic events, the velocity distribution of electrons reveals a dual structure with a thermal (Maxwellian) core and a suprathermal (kappa) halo. This article presents a detailed observational analysis of these two components, providing estimations of their temperatures and temperature anisotropies, and decoding any potential interdependence that their properties may indicate. The dataset used in this study includes more than 120 000 of the distributions measured by three missions in the ecliptic within an extended range of heliocentric distances from 0.3 to over 4 AU. The core temperature is found to decrease with the radial distance, while the halo temperature slightly increases, clarifying an apparent contradiction in previous observational analyses and providing valuable clues about the temperature of the kappa-distributed populations. For low values of the power-index kappa, these two components manifest a clear tendency to deviate from isotropy in the same direction, which seems to confirm the existence of mechanisms with similar effects on both components, e.g., the solar wind expansion, or the particle heating by the fluctuations. However, the existence of plasma states with anticorrelated anisotropies of the core and halo populations and the increase in their number for high values of the power-index kappa suggest a dynamic interplay of these components, mediated, most probably, by the anisotropy-driven instabilities.

  15. Prediction and experimental validation of stagnation temperature attained by a solar cooker of hot box type

    Energy Technology Data Exchange (ETDEWEB)

    Narasimha Rao, A. V; Srikrishna, D. V. N [Warangal (India)

    2000-07-01

    A hot box type solar cooker, having double glass covers and a plane mirror reflector, is tested for stagnation temperature. A computer code is developed based on the analytical model proposed by Vaishya et. al. The global and beam components of solar radiation measured at Warangal are made use to predict the stagnation temperature of the cooker. The observed values of stagnation temperature at Warangal are compared with those of predicted values. A good agreement of the measured and observed values of the stagnation temperature is observed during the afternoon period. The lag in the observed values during the forenoon may be due to thermal inertia of the cooker. [Spanish] Se probo una estufa solar de tipo caja caliente con cubiertas dobles de vidrio y un espejo reflector plano para medir la temperatura de estancamiento. Se desarrollo un codigo de computacion basado en el modelo analitico propuesto por Vaishya et. al. Los componentes de la radiacion solar globales y de rayo medidos en Warangal se usan para predecir la temperatura de estancamiento de la estufa. Los valores observados de la temperatura de estancamiento en Warangal se comparan con los valores predichos. Se aprecia una buena concidencia de los valores medidos y observados de la temperatura de estancamiento durante el periodo de la tarde. El retraso de los valores observados durante la manana puede ser debido a la inercia termica de la estufa.

  16. NST: Thermal Modeling for a Large Aperture Solar Telescope

    Science.gov (United States)

    Coulter, Roy

    2011-05-01

    Late in the 1990s the Dutch Open Telescope demonstrated that internal seeing in open, large aperture solar telescopes can be controlled by flushing air across the primary mirror and other telescope structures exposed to sunlight. In that system natural wind provides a uniform air temperature throughout the imaging volume, while efficiently sweeping heated air away from the optics and mechanical structure. Big Bear Solar Observatory's New Solar Telescope (NST) was designed to realize that same performance in an enclosed system by using both natural wind through the dome and forced air circulation around the primary mirror to provide the uniform air temperatures required within the telescope volume. The NST is housed in a conventional, ventilated dome with a circular opening, in place of the standard dome slit, that allows sunlight to fall only on an aperture stop and the primary mirror. The primary mirror is housed deep inside a cylindrical cell with only minimal openings in the side at the level of the mirror. To date, the forced air and cooling systems designed for the NST primary mirror have not been implemented, yet the telescope regularly produces solar images indicative of the absence of mirror seeing. Computational Fluid Dynamics (CFD) analysis of the NST primary mirror system along with measurements of air flows within the dome, around the telescope structure, and internal to the mirror cell are used to explain the origin of this seemingly incongruent result. The CFD analysis is also extended to hypothetical systems of various scales. We will discuss the results of these investigations.

  17. Solar thermal rocket engine (STRE) thrust characteristics at the change of engine operation mode and of the flight vehicle attitude in the solar system

    Science.gov (United States)

    Kudrin, O. I.

    1993-10-01

    Relationships are presented which describe changes in the thrust and specific impulse of a solar thermal rocket engine due to a change in the flow rate of the working fluid (hydrogen). Expressions are also presented which describe the variation of the STRE thrust and specific impulse with the distance between the flight vehicle and the sun. Results of calculations are presented for an STRE with afterburning of the working fluid (hydrogen + oxygen) using hydrogen heating by solar energy to a temperature of 2360 K.

  18. Formation of the thermal infrared continuum in solar flares

    Science.gov (United States)

    Simões, Paulo J. A.; Kerr, Graham S.; Fletcher, Lyndsay; Hudson, Hugh S.; Giménez de Castro, C. Guillermo; Penn, Matt

    2017-09-01

    Aims: Observations of the Sun with the Atacama Large Millimeter Array have now started, and the thermal infrared will regularly be accessible from the NSF's Daniel K. Inouye Solar Telescope. Motivated by the prospect of these new data, and by recent flare observations in the mid infrared, we set out here to model and understand the source of the infrared continuum in flares, and to explore its diagnostic capability for the physical conditions in the flare atmosphere. Methods: We use the one-dimensional (1D) radiation hydrodynamics code RADYN to calculate mid-infrared continuum emission from model atmospheres undergoing sudden deposition of energy by non-thermal electrons. Results: We identify and characterise the main continuum thermal emission processes relevant to flare intensity enhancement in the mid- to far-infrared (2-200 μm) spectral range as free-free emission on neutrals and ions. We find that the infrared intensity evolution tracks the energy input to within a second, albeit with a lingering intensity enhancement, and provides a very direct indication of the evolution of the atmospheric ionisation. The prediction of highly impulsive emission means that, on these timescales, the atmospheric hydrodynamics need not be considered in analysing the mid-IR signatures.

  19. Interfacial thermal degradation in inverted organic solar cells

    Energy Technology Data Exchange (ETDEWEB)

    Greenbank, William; Hirsch, Lionel; Wantz, Guillaume; Chambon, Sylvain, E-mail: sylvain.chambon@ims-bordeaux.fr [University of Bordeaux, CNRS, Bordeaux INP, IMS, UMR 5218, F-33405 Talence (France)

    2015-12-28

    The efficiency of organic photovoltaic (OPV) solar cells is constantly improving; however, the lifetime of the devices still requires significant improvement if the potential of OPV is to be realised. In this study, several series of inverted OPV were fabricated and thermally aged in the dark in an inert atmosphere. It was demonstrated that all of the devices undergo short circuit current-driven degradation, which is assigned to morphology changes in the active layer. In addition, a previously unreported, open circuit voltage-driven degradation mechanism was observed that is highly material specific and interfacial in origin. This mechanism was specifically observed in devices containing MoO{sub 3} and silver as hole transporting layers and electrode materials, respectively. Devices with this combination were among the worst performing devices with respect to thermal ageing. The physical origins of this mechanism were explored by Rutherford backscattering spectrometry and atomic force microscopy and an increase in roughness with thermal ageing was observed that may be partially responsible for the ageing mechanism.

  20. Temperature Dependence of Solar Light Assisted CO2 Reduction on Ni Based Photocatalyst

    OpenAIRE

    Albero Sancho, Josep; García Gómez, Hermenegildo; Corma Canós, Avelino

    2016-01-01

    Methanation of CO2 by H-2 can be in the future an important reaction to store the surplus of renewable electricity during production peaks. The catalytic thermal CO2 methanation (the Sabatier reaction) can be carried out at temperatures above 250 degrees C using Ni supported on silica-alumina (Ni/SiO2-Al2O3). Recently it has been observed that this exothermic reaction can be promoted by solar light irradiation of Ni/SiO2-Al2O3 at initial near ambient temperatures. In the present work we provi...

  1. A short term test method for large installed solar thermal systems

    Energy Technology Data Exchange (ETDEWEB)

    Beikircher, T.; Benz, N.; Gut, M. [Bavarian Centre for Applied Energy Research, Div. Solar Thermal and Biomass, Munich (Germany); Drueck, H. [Univ. Stuttgart, Inst. fuer Thermodynamik und Waermetechnik, Stuttgart (Germany)

    2000-07-01

    In order to determine the yearly energy output of solar thermal systems, we developed a quick, reliable and low-cost short term test method (ISTT-procedure), based on the adaptation of a dynamic, component based simulation model to transient measuring data from about 6 weeks. The method is especially helpful to quickly judge the fulfilments of contracts concerned with guaranteed solar results (GSR). On the experimental side, an autarkic wireless measuring station for the meteorological quantities has been developed, new surface temperature sensors have been constructed and ultrasonic volume flow gauges as well as a mobile magnetic inductive volume flow station have been applied. Thus expensive wiring and cutting off the fluid circuits can be avoided. For the dynamic evaluation procedure, we tested different simulation programs using the multi-port store model with four free parameters and an extended matched flow collector model with eight free parameters including pipes and a heat exchanger. Criteria for a measuring sequence sufficient for a reliable parameter identification and experimental procedures for their realization have been deduced and the parameters were numerically identified from insitu-measuring sequences not exceeding 6 weeks. The ISTT- procedure allows to separate the influence of the operation conditions (weather and hot water demand) from the performance of the solar system. It is possible to predict the yearly solar energy gain for arbitrary standard operation conditions, especially for those supposed by the planner. In this paper, the ISTT-procedure is generally described and exemplary carried out and validated for a large solar thermal system with 110 m{sup 2} flat-plate-collectors. The results of the ISTT-method excellently agree to independent long-term measurements for the energy delivered by the collector field (GSR 1) as well as for the energy discharged from the buffer store (GSR2). (au)

  2. Estec2003: European solar thermal energy conference. Proceedings; Estec2003: Europaeische Solarthermie-Konferenz. Tagungsband

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2003-07-01

    In December 2002 more than 40 solar thermal companies and associations joined forces in the European Solar Thermal Industry Federation (ESTIF), to strengthen support for this clean technology on the European level. ESTIF aims at building a close partnership between industry and public authorities in order to overcome the main barriers to growth. Over the last 6 months we have seen some positive developments, which we could build upon. Here are some examples: 1. Germany, the country with the largest demand for solar thermal technology, is back on track to repeat the growth rates we have witnessed in the 1990s. 2. The rules for the solar Keymark quality label were approved by CEN board in January 2003. 3. The city of Madrid became the first European capital to follow the example of Barcelona in requiring the use of solar thermal in new residential buildings. 4. The long awaited ''Sun in Action II - a solar thermal strategy for Europe was published last month. 5. Now, the first European Solar Thermal Energy Conference brings together decision makers from industry and politics to discuss the future of renewable heating and cooling in Europe. - Solar thermal has a great potential - 1.4 billion square meters in the 15 EU member states alone. 99% of this potential are still to be developed. ESTIF has made it its mission 'to achieve high priority and acceptance for solar thermal as a key element for sustainable heating and cooling in Europe and to work for the implementation, as soon as possible, of all steps necessary to realise the high potential of solar thermal'. With estec2003 we offer a platform to exchange information and opinions concerning how this goal can be achieved. The developments in different countries show that the use of solar thermal technologies does not depend on climatic conditions alone. (orig.)

  3. Automatic Thermal Control System with Temperature Difference or Derivation Feedback

    Directory of Open Access Journals (Sweden)

    Darina Matiskova

    2016-02-01

    Full Text Available Automatic thermal control systems seem to be non-linear systems with thermal inertias and time delay. A controller is also non-linear because its information and power signals are limited. The application of methods that are available to on-linear systems together with computer simulation and mathematical modelling creates a possibility to acquire important information about the researched system. This paper provides a new look at the heated system model and also designs the structure of the thermal system with temperature derivation feedback. The designed system was simulated by using a special software in Turbo Pascal. Time responses of this system are compared to responses of a conventional thermal system. The thermal system with temperature derivation feedback provides better transients, better quality of regulation and better dynamical properties.

  4. State of the art on high temperature thermal energy storage for power generation. Part 1. Concepts, materials and modellization

    Energy Technology Data Exchange (ETDEWEB)

    Gil, Antoni; Medrano, Marc; Martorell, Ingrid; Cabeza, Luisa F. [GREA Innovacio Concurrent, Universitat de Lleida, Pere de Cabrera s/n, 25001-Lleida (Spain); Lazaro, Ana; Dolado, Pablo; Zalba, Belen [Instituto de Investigacion en Ingenieria de Aragon, I3A, Grupo de Ingenieria Termica y Sistemas Energeticos (GITSE), Dpto. Ingenieria Mecanica, Area de Maquinas y Motores Termicos, Universidad de Zaragoza, Campus Politecnico Rio Ebro, Edificio ' Agustin de Betancourt' , Maria de Luna s/n, 50018 Zaragoza (Spain)

    2010-01-15

    Concentrated solar thermal power generation is becoming a very attractive renewable energy production system among all the different renewable options, as it has have a better potential for dispatchability. This dispatchability is inevitably linked with an efficient and cost-effective thermal storage system. Thus, of all components, thermal storage is a key one. However, it is also one of the less developed. Only a few plants in the world have tested high temperature thermal energy storage systems. In this paper, the different storage concepts are reviewed and classified. All materials considered in literature or plants are listed. And finally, modellization of such systems is reviewed. (author)

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

    OpenAIRE

    Sundaram, Vijay; Natarajan, Vasant

    2010-01-01

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

  6. Thermal Modeling of the Mars Reconnaissance Orbiter's Solar Panel and Instruments during Aerobraking

    Science.gov (United States)

    Dec, John A.; Gasbarre, Joseph F.; Amundsen, Ruth M.

    2007-01-01

    The Mars Reconnaissance Orbiter (MRO) launched on August 12, 2005 and started aerobraking at Mars in March 2006. During the spacecraft s design phase, thermal models of the solar panels and instruments were developed to determine which components would be the most limiting thermally during aerobraking. Having determined the most limiting components, thermal limits in terms of heat rate were established. Advanced thermal modeling techniques were developed utilizing Thermal Desktop and Patran Thermal. Heat transfer coefficients were calculated using a Direct Simulation Monte Carlo technique. Analysis established that the solar panels were the most limiting components during the aerobraking phase of the mission.

  7. Temperature measurements using multicolor pyrometry in thermal radiation heating environments.

    Science.gov (United States)

    Fu, Tairan; Liu, Jiangfan; Duan, Minghao; Zong, Anzhou

    2014-04-01

    Temperature measurements are important for thermal-structural experiments in the thermal radiation heating environments such as used for thermal-structural stress analyses. This paper describes the use of multicolor pyrometry for the measurements of diffuse surfaces in thermal radiation environments that eliminates the effects of background radiation reflections and unknown emissivities based on a least-squares algorithm. The near-infrared multicolor pyrometer had a spectral range of 1100-2400 nm, spectrum resolution of 6 nm, maximum sampling frequency of 2 kHz, working distance of 0.6 m to infinity, temperature range of 700-1700 K. The pyrometer wavelength response, nonlinear intensity response, and spectral response were all calibrated. The temperature of a graphite sample irradiated by quartz lamps was then measured during heating and cooling using the least-squares algorithm based on the calibrated irradiation data. The experiments show that higher temperatures and longer wavelengths are more suitable for the thermal measurements in the quartz lamp radiation heating system. This analysis provides a valuable method for temperature measurements of diffuse surfaces in thermal radiation environments.

  8. Temperature measurements using multicolor pyrometry in thermal radiation heating environments

    Energy Technology Data Exchange (ETDEWEB)

    Fu, Tairan, E-mail: trfu@mail.tsinghua.edu.cn [Key Laboratory for Thermal Science and Power Engineering of Ministry of Education, Department of Thermal Engineering, Tsinghua University, Beijing 100084 (China); Beijing Key Laboratory of CO2 Utilization and Reduction Technology, Beijing 100084 (China); Liu, Jiangfan; Duan, Minghao; Zong, Anzhou [Key Laboratory for Thermal Science and Power Engineering of Ministry of Education, Department of Thermal Engineering, Tsinghua University, Beijing 100084 (China)

    2014-04-15

    Temperature measurements are important for thermal-structural experiments in the thermal radiation heating environments such as used for thermal-structural stress analyses. This paper describes the use of multicolor pyrometry for the measurements of diffuse surfaces in thermal radiation environments that eliminates the effects of background radiation reflections and unknown emissivities based on a least-squares algorithm. The near-infrared multicolor pyrometer had a spectral range of 1100–2400 nm, spectrum resolution of 6 nm, maximum sampling frequency of 2 kHz, working distance of 0.6 m to infinity, temperature range of 700–1700 K. The pyrometer wavelength response, nonlinear intensity response, and spectral response were all calibrated. The temperature of a graphite sample irradiated by quartz lamps was then measured during heating and cooling using the least-squares algorithm based on the calibrated irradiation data. The experiments show that higher temperatures and longer wavelengths are more suitable for the thermal measurements in the quartz lamp radiation heating system. This analysis provides a valuable method for temperature measurements of diffuse surfaces in thermal radiation environments.

  9. Temperature measurements using multicolor pyrometry in thermal radiation heating environments

    Science.gov (United States)

    Fu, Tairan; Liu, Jiangfan; Duan, Minghao; Zong, Anzhou

    2014-04-01

    Temperature measurements are important for thermal-structural experiments in the thermal radiation heating environments such as used for thermal-structural stress analyses. This paper describes the use of multicolor pyrometry for the measurements of diffuse surfaces in thermal radiation environments that eliminates the effects of background radiation reflections and unknown emissivities based on a least-squares algorithm. The near-infrared multicolor pyrometer had a spectral range of 1100-2400 nm, spectrum resolution of 6 nm, maximum sampling frequency of 2 kHz, working distance of 0.6 m to infinity, temperature range of 700-1700 K. The pyrometer wavelength response, nonlinear intensity response, and spectral response were all calibrated. The temperature of a graphite sample irradiated by quartz lamps was then measured during heating and cooling using the least-squares algorithm based on the calibrated irradiation data. The experiments show that higher temperatures and longer wavelengths are more suitable for the thermal measurements in the quartz lamp radiation heating system. This analysis provides a valuable method for temperature measurements of diffuse surfaces in thermal radiation environments.

  10. 100 °C Thermal Stability of Printable Perovskite Solar Cells Using Porous Carbon Counter Electrodes.

    Science.gov (United States)

    Baranwal, Ajay K; Kanaya, Shusaku; Peiris, T A Nirmal; Mizuta, Gai; Nishina, Tomoya; Kanda, Hiroyuki; Miyasaka, Tsutomu; Segawa, Hiroshi; Ito, Seigo

    2016-09-22

    Many efforts have been made towards improving perovskite (PVK) solar cell stability, but their thermal stability, particularly at 85 °C (IEC 61646 climate chamber tests), remains a challenge. Outdoors, the installed solar cell temperature can reach up to 85 °C, especially in desert regions, providing sufficient motivation to study the effect of temperature stress at or above this temperature (e.g., 100 °C) to confirm the commercial viability of PVK solar cells for industrial companies. In this work, a three-layer printable HTM-free CH3 NH3 PbI3 PVK solar cell with a mesoporous carbon back contact and UV-curable sealant was fabricated and tested for thermal stability over 1500 h at 100 °C. Interestingly, the position of the UV-curing glue was found to drastically affect the device stability. The side-sealed cells show high PCE stability and represent a large step toward commercialization of next generation organic-inorganic lead halide PVK solar cells. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  11. Prediction of Air Flow and Temperature Profiles Inside Convective Solar Dryer

    Directory of Open Access Journals (Sweden)

    Marian Vintilă

    2014-11-01

    Full Text Available Solar tray drying is an effective alternative for post-harvest processing of fruits and vegetables. Product quality and uniformity of the desired final moisture content are affected by the uneven air flow and temperature distribution inside the drying chamber. The purpose of this study is to numerically evaluate the operation parameters of a new indirect solar dryer having an appropriate design based on thermal uniformity inside the drying chamber, low construction costs and easy accessibility to resources needed for manufacture. The research was focused on both the investigation of different operation conditions and analysis of the influence of the damper position, which is incorporated into the chimney, on the internal cabinet temperature and air flow distribution. Numerical simulation was carried out with Comsol Multiphysics CFD commercial code using a reduced 2D domain model by neglecting any end effects from the side walls. The analysis of the coupled thermal-fluid model provided the velocity field, pressure distribution and temperature distribution in the solar collector and in the drying chamber when the damper was totally closed, half open and fully open and for different operation conditions. The predicted results were compared with measurements taken in-situ. With progressing computing power, it is conceivable that CFD will continue to provide explanations for more fluid flow, heat and mass transfer phenomena, leading to better equipment design and process control for the food industry.

  12. Study of Solar Cells Operation under the Influence of Temperature

    Directory of Open Access Journals (Sweden)

    HOBLE Dorel Anton

    2013-10-01

    Full Text Available The paper is focused on an experimental study on the functioning of photovoltaic cells at high temperatures. Having regard to that systems based on the semiconductors components, at high temperatures,above normal operating current appear a current in addition, due to the phenomenon of intrinsic thermal generation, charge carries, it is possible destructive phenomena appears. The work wishes to reveal howthe operation of photovoltaic cells at high temperatures influence the operating parameters of their.

  13. Solar Array at Very High Temperatures: Ground Tests

    Science.gov (United States)

    Vayner, Boris

    2016-01-01

    Solar array design for any spacecraft is determined by the orbit parameters. For example, operational voltage for spacecraft in Low Earth Orbit (LEO) is limited by significant differential charging due to interactions with low temperature plasma. In order to avoid arcing in LEO, solar array is designed to generate electrical power at comparatively low voltages (below 100 volts) or to operate at higher voltages with encapsulation of all suspected discharge locations. In Geosynchronous Orbit (GEO) differential charging is caused by energetic electrons that produce differential potential between the coverglass and the conductive spacecraft body in a kilovolt range. In such a case, the weakly conductive layer over coverglass, indium tin oxide (ITO) is one of the possible measures to eliminate dangerous discharges on array surface. Temperature variations for solar arrays in both orbits are measured and documented within the range of minus150 degrees Centigrade to plus 1100 degrees Centigrade. This wide interval of operational temperatures is regularly reproduced in ground tests with radiative heating and cooling inside a shroud with flowing liquid nitrogen. The requirements to solar array design and tests turn out to be more complicated when planned trajectory crosses these two orbits and goes closer to the Sun. The conductive layer over coverglass causes a sharp increase in parasitic current collected from LEO plasma, high temperature may cause cracks in encapsulating (Room Temperature Vulcanizing (RTV) material; radiative heating of a coupon in vacuum chamber becomes practically impossible above 1500 degrees Centigrade; conductivities of glass and adhesive go up with temperature that decrease array efficiency; and mechanical stresses grow up to critical magnitudes. A few test arrangements and respective results are presented in current paper. Coupons were tested against arcing in simulated LEO and GEO environments under elevated temperatures up to 2000 degrees

  14. Thermal Aware Floorplanning Incorporating Temperature Dependent Wire Delay Estimation

    DEFF Research Database (Denmark)

    Winther, AndreasThor; Liu, Wei; Nannarelli, Alberto

    2015-01-01

    Temperature has a negative impact on metal resistance and thus wire delay. In state-of-the-art VLSI circuits, large thermal gradients usually exist due to the uneven distribution of heat sources. The difference in wire temperature can lead to performance mismatch because wires of the same length ...

  15. On the effect of temperature dependent thermal conductivity on ...

    African Journals Online (AJOL)

    We consider the effect of temperature dependent thermal conductivity on temperature rise in biologic tissues during microwave heating. The method of asymptotic expansion is used for finding solution. An appropriate matching procedure was used in our method. Our result reveals the possibility of multiple solutions and it ...

  16. Climate variation based on temperature and solar radiation data ...

    African Journals Online (AJOL)

    ckaonga

    City, Malawi for a 29-year period (1985 to 2013) were assessed for the possibility of climate variation. In addition, the concentration of carbon ... Key words: Climate variation, solar radiation, temperature, weather. INTRODUCTION. The world's climate ..... changes and nocturnal global warming. Science 283 (5399):229-231.

  17. the trends in temperature and solar irradiance for zaria, north ...

    African Journals Online (AJOL)

    Dogara et al.

    leading to the global warming concept. Keywords: Trend, Temperature, Solar Irradiance, Zaria. INTRODUCTION. The study of the rates of climatic change and their impact on the environment and society is important and essential to predicting global and regional climatic variations and to determining the extent of human ...

  18. On the minimum temperature of the quiet solar chromospheres

    NARCIS (Netherlands)

    Leenaarts, J.; Carlsson, M.; Hansteen, V.; Gudiksen, B.V.

    2011-01-01

    Aims. We aim to provide an estimate of the minimum temperature of the quiet solar chromosphere. Methods. We perform a 2D radiation-MHD simulation spanning the upper convection zone to the lower corona. The simulation includes non-LTE radiative transfer and an equation-of-state that includes

  19. Improvement of energy performances of existing buildings by application of solar thermal systems

    Directory of Open Access Journals (Sweden)

    Krstić-Furundžić Aleksandra

    2009-01-01

    Full Text Available Improvement of energy performances of the existing buildings in the suburban settlement Konjarnik in Belgrade, by the application of solar thermal systems is the topic presented in this paper. Hypothetical models of building improvements are created to allow the benefits of applying solar thermal collectors to residential buildings in Belgrade climate conditions to be estimated. This case study presents different design variants of solar thermal collectors integrated into a multifamily building envelope. The following aspects of solar thermal systems integration are analyzed in the paper: energy, architectural, ecological and economic. The results show that in Belgrade climatic conditions significant energy savings and reduction of CO2 emissions can be obtained with the application of solar thermal collectors.

  20. Two-stage solar power tower cavity-receiver design and thermal performance analysis

    Science.gov (United States)

    Pang, Liping; Wang, Ting; Li, Ruihua; Yang, Yongping

    2017-06-01

    New type of two-stage solar power tower cavity-receiver is designed and a calculating procedure of radiation, convection and flow under the Gaussian heat flux is established so as to determine the piping layout and geometries in the receiver I and II and the heat flux distribution in different positions is obtained. Then the main thermal performance on water/steam temperature, steam quality, wall temperature along the typical tubes and pressure drop are specified according to the heat transfer and flow characteristics of two-phase flow. Meanwhile, a series of systematic design process is promoted and analysis on thermal performance of the two receivers is conducted. Results show that this type of two-stage cavity-receivers can minimize the size and reduce the mean temperature of receiver I while raise the average heat flux, thus increase the thermal efficiency of the two receivers; besides, the multiple serpentine tubes from header can make a more uniform distribution of the outlet parameters, preventing wall overheated.

  1. Standard Practice for Evaluating Solar Absorptive Materials for Thermal Applications

    CERN Document Server

    American Society for Testing and Materials. Philadelphia

    2007-01-01

    1.1 This practice covers a testing methodology for evaluating absorptive materials used in flat plate or concentrating collectors, with concentrating ratios not to exceed five, for solar thermal applications. This practice is not intended to be used for the evaluation of absorptive surfaces that are (1) used in direct contact with, or suspended in, a heat-transfer liquid, (that is, trickle collectors, direct absorption fluids, etc.); (2) used in evacuated collectors; or (3) used in collectors without cover plate(s). 1.2 Test methods included in this practice are property measurement tests and aging tests. Property measurement tests provide for the determination of various properties of absorptive materials, for example, absorptance, emittance, and appearance. Aging tests provide for exposure of absorptive materials to environments that may induce changes in the properties of test specimens. Measuring properties before and after an aging test provides a means of determining the effect of the exposure. 1.3 Th...

  2. Solar thermal upper stage: Economic advantage and development status

    Science.gov (United States)

    Adams, Alan M.

    1995-01-01

    A solar thermal upper stage (STUS) is envisioned as a propulsive concept for the future. The STUS will be used for low Earth orbit (LEO) to geostationary-Earth orbit (GEO) transfer and for planetary exploration missions. The STUS offers significant performance gains over conventional chemical propulsion systems. These performance gains translate into a more economical, more efficient method of placing useful payloads in space and maximizing the benefits derived from space activity. This paper will discuss the economical advantages of an STUS compared to conventional chemical propulsion systems, the potential market for an STUS, and the recent activity in the development of an STUS. The results of this assessment combined with the performance gains, will provide a strong justification for the development of an STUS.

  3. High Temperature Thermal Properties of Bentonite Foundry Sand

    Directory of Open Access Journals (Sweden)

    Krajewski P.K.

    2015-06-01

    Full Text Available The paper presents results of measuring thermal conductivity and heat capacity of bentonite foundry sand in temperature range ambient - 900­­°C. During the experiments a technical purity Cu plate was cast into the green-sand moulds. Basing on measurements of the mould temperature field during the solidification of the casting, the temperature relationships of the measured properties were evaluated. It was confirmed that water vaporization strongly influences thermal conductivity of the moulding sand in the first period of the mould heating by the poured casting.

  4. Energetic and exergetic analysis of Rankine cycles for solar power plants with parabolic trough and thermal storage

    Directory of Open Access Journals (Sweden)

    Cenuşă Victor-Eduard

    2016-01-01

    Full Text Available The paper analyzes the “secondary” circuit (for thermodynamic conversion of a Concentrated Solar Power (CSP plant with thermodynamic cycle, whose mirrors field supplies a thermal power, averaged over a sunny day, of about 100 MW heat. We study the case of parabolic trough solar collector using silicone oil in the “primary” circuit, which limits the peak temperature below 400 °C. The “primary” circuit uses thermal storage, allowing a delay between the power generation in rapport with the solar energy capture. We choose a water-steam cycle, type Hirn. For increasing its efficiency, it has regenerative feed water preheating and steam reheating. We compared, energetic and exergetic, two types of cycles, using a numerical model with iterative structure, developed by the authors. The results showed that the simplified design achieves practically the same thermodynamic performances with the advanced one.

  5. Second national symposium `Thermal solar energy`; Zweites nationales Symposium Thermische Solarenergie

    Energy Technology Data Exchange (ETDEWEB)

    1992-12-31

    The symposium on thermal solar energy utilization focussed on embracing aspects of thermal solar energy, standardization, testing, quality assurance, and the use of passive solar energy. Each of the 23 papers given at the meeting was abstracted for separate entry into the data base. (BWI). [Deutsch] Im Mittelpunkt des Symposiums zur thermischen Solarenergienutzung stehen uebergreifende Aspekte der thermischen Solarenergie, Normung, Test und Qualitaetssicherung sowie die Nutzung der passiven Solarenergie. Fuer alle 23 enthaltenen Fachbeitraege wurde eine gesonderte inhaltliche Erschliessung durchgefuehrt. (BWI).

  6. STDAC: Solar Thermal Design Assistance Center annual report fiscal year 1994

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1994-12-31

    The Solar Thermal Design Assistance Center (STDAC) at Sandia is a resource provided by the DOE Solar Thermal Program. The STDAC`s major objective is to accelerate the use of solar thermal systems by providing direct technical assistance to users in industry, government, and foreign countries; cooperating with industry to test, evaluate, and develop renewable energy systems and components; and educating public and private professionals, administrators, and decision makers. This FY94 report highlights the activities and accomplishments of the STDAC. In 1994, the STDAC continued to provide significant direct technical assistance to domestic and international organizations in industry, government, and education, Applying solar thermal technology to solve energy problems is a vital element of direct technical assistance. The STDAC provides information on the status of new, existing, and developing solar technologies; helps users screen applications; predicts the performance of components and systems; and incorporates the experience of Sandia`s solar energy personnel and facilities to provide expert guidance. The STDAC directly enhances the US solar industry`s ability to successfully bring improved systems to the marketplace. By collaborating with Sandia`s Photovoltaic Design Assistance Center and the National Renewable Energy Laboratory the STDAC is able to offer each customer complete service in applying solar thermal technology. At the National Solar Thermal Test Facility the STDAC tests and evaluates new and innovative solar thermal technologies. Evaluations are conducted in dose cooperation with manufacturers, and the results are used to improve the product and/or quantify its performance characteristics. Manufacturers, in turn, benefit from the improved design, economic performance, and operation of their solar thermal technology. The STDAC provides cost sharing and in-kind service to manufacturers in the development and improvement of solar technology.

  7. Low Molecular Weight Norbornadiene Derivatives for Molecular Solar?Thermal Energy Storage

    OpenAIRE

    Quant, Maria; Lennartson, Anders; Dreos, Ambra; Kuisma, Mikael; Erhart, Paul; B?rjesson, Karl; Moth?Poulsen, Kasper

    2016-01-01

    Abstract Molecular solar?thermal energy storage systems are based on molecular switches that reversibly convert solar energy into chemical energy. Herein, we report the synthesis, characterization, and computational evaluation of a series of low molecular weight (193?260?g?mol?1) norbornadiene?quadricyclane systems. The molecules feature cyano acceptor and ethynyl?substituted aromatic donor groups, leading to a good match with solar irradiation, quantitative photo?thermal conversion between t...

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

    Science.gov (United States)

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

    2016-05-01

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

  9. Lightweight High-Temperature Thermal Insulation

    Science.gov (United States)

    Wagner, W. R.; Fasheh, J. I.

    1985-01-01

    Fine Ni/Cr fibers sintered into corrosion-resistant, fireproof batt. Possible applications include stoves, furnaces, safes, fire clothing, draperies in public buildings, wall firebreaks, airplane walls, and jetengine components. New insulation takes advantage of some of same properties of nickel/chromium alloy useful in heating elements in toasters, namely, corrosion and oxidation resistance even at high temperatures.

  10. A solar thermal electric power plant for small communities

    Science.gov (United States)

    Holl, R. J.

    1979-01-01

    A solar power plant has been designed with a rating of 1000-kW electric and a 0.4 annual capacity factor. It was configured as a prototype for plants in the 1000 to 10,000-kWe size range for application to small communities or industrial users either grid-connected or isolated from a utility grid. A small central receiver was selected for solar energy collection after being compared with alternative distributed collectors. Further trade studies resulted in the selection of Hitec (heat transfer salt composed of 53 percent KNO3, 40 percent NaNO2, 7 percent NaNO3) as both the receiver coolant and the sensible heat thermal stroage medium and the steam Rankine cycle for power conversion. The plant is configured with road-transportable units to accommodate remote sites and minimize site assembly requirements. Results of the analyses indicate that busbar energy costs are competitive with diesel-electric plants in certain situations, e.g., off-grid, remote regions with high insolation. Sensitivity of energy costs to plant power rating and system capacity factor are given.

  11. Experimental Study on the Thermal Start-Up Performance of the Graphene/Water Nanofluid-Enhanced Solar Gravity Heat Pipe

    Directory of Open Access Journals (Sweden)

    Shanguo Zhao

    2018-01-01

    Full Text Available The solar gravity heat pipe has been widely used for solar thermal water heating because of its high efficient heat transfer and thermal diode characteristics. Operated on fluctuant and low intensity solar radiation conditions, a solar gravity heat pipe may frequently start up. This severely affects its solar collection performance. To enhance the thermal performance of the solar gravity heat pipe, this study proposes using graphene/water nanofluid as the working fluid instead of deionized water. The stability of the prepared graphene/water nanofluid added with PVP was firstly investigated to obtain the optimum mass ratios of the added dispersant. Thermophysical properties—including the thermal conductivity and viscosity—of nanofluid with various graphene nanoplatelets (GNPs concentrations were measured at different temperatures for further analysis. Furthermore, based on the operational evaluation on a single heat pipe’s start-up process, the performance of nanofluid-enhanced solar gravity heat pipes using different concentrations of GNPs were compared by using water heating experiments. Results indicated that the use of 0.05 wt % graphene/water nanofluid instead of water could achieve a 15.1% and 10.7% reduction in start-up time under 30 and 60 W input heating conditions, respectively. Consequently, a higher thermal efficiency for solar collection could be expected.

  12. Experimental Study on the Thermal Start-Up Performance of the Graphene/Water Nanofluid-Enhanced Solar Gravity Heat Pipe.

    Science.gov (United States)

    Zhao, Shanguo; Xu, Guoying; Wang, Ning; Zhang, Xiaosong

    2018-01-28

    The solar gravity heat pipe has been widely used for solar thermal water heating because of its high efficient heat transfer and thermal diode characteristics. Operated on fluctuant and low intensity solar radiation conditions, a solar gravity heat pipe may frequently start up. This severely affects its solar collection performance. To enhance the thermal performance of the solar gravity heat pipe, this study proposes using graphene/water nanofluid as the working fluid instead of deionized water. The stability of the prepared graphene/water nanofluid added with PVP was firstly investigated to obtain the optimum mass ratios of the added dispersant. Thermophysical properties-including the thermal conductivity and viscosity-of nanofluid with various graphene nanoplatelets (GNPs) concentrations were measured at different temperatures for further analysis. Furthermore, based on the operational evaluation on a single heat pipe's start-up process, the performance of nanofluid-enhanced solar gravity heat pipes using different concentrations of GNPs were compared by using water heating experiments. Results indicated that the use of 0.05 wt % graphene/water nanofluid instead of water could achieve a 15.1% and 10.7% reduction in start-up time under 30 and 60 W input heating conditions, respectively. Consequently, a higher thermal efficiency for solar collection could be expected.

  13. Photo-thermal characteristics of water-based Fe3O4@SiO2 nanofluid for solar-thermal applications

    Science.gov (United States)

    Khashan, Saud; Dagher, Sawsan; Omari, Salahaddin Al; Tit, Nacir; Elnajjar, Emad; Mathew, Bobby; Hilal-Alnaqbi, Ali

    2017-05-01

    This work proposes and demonstrates the novel idea of using Fe3O4@SiO2 core/shell structure nanoparticles (NPs) to improve the solar thermal conversion efficiency. Magnetite (Fe3O4) NPs are synthesized by controlled co-precipitation method. Fe3O4@SiO2 NPs are prepared based on sol-gel approach, then characterized. Water-based Fe3O4@SiO2 nanofluid is prepared and usedto illustrate the photo-thermal conversion characteristics of a solar collector under solar simulator. The temperature rise characteristics of the nanofluids are investigated at different heights of the solar collector, for duration of 300 min, under a solar intensity of 1000 W m-2. The experimental results show that Fe3O4@SiO2 NPs have a core/shell structure with spherical morphology and size of about 400 nm. Fe3O4@SiO2/H2O nanofluid enhances the photo-thermal conversion efficiency compared with base fluid and Fe3O4/H2O nanofluid, since the silica coating improves both the thermodynamic stability of the nanofluid and the light absorption effectiveness of the NPs. At a concentration of 1 mg/1 ml of Fe3O4@SiO2/H2O, and with the utilization of kerosene into the solar collector, and exposure for radiation for 5 min, the photo-thermal conversion efficiency has shown an enhancement at the bottom of the collector of about 32.9% compared to the base fluid.

  14. Investigation on I-V for Different Heating Temperatures of Nanocomposited MEH-PPV:CNTs Organic Solar Cells

    Directory of Open Access Journals (Sweden)

    M. S. P. Sarah

    2012-01-01

    Full Text Available This paper discussed the effect of different thermal evaporation treatments for nanocomposited MEH-PPV:CNTs thin films towards the performance of organic solar cells. The configuration of the organic solar cells is ITO/MEH-PPV:CNTs/Au. The heating temperature was varied from, as deposited, 50°C, 75°C, and 100°C. From the results, we observed that the efficiency increase slightly before decreasing back at 100°C. The highest efficiency was solar cells heated at 75°C with efficiency 0.001% which is supported by the I-V characteristics and also by the absorption spectra.

  15. High-temperature photochemical destruction of toxic organic wastes using concentrated solar radiation

    Energy Technology Data Exchange (ETDEWEB)

    Dellinger, B.; Graham, J.L.; Berman, J.M.; Taylor, P.H. [Dayton Univ., OH (United States)

    1994-05-01

    Application of concentrated solar energy has been proposed to be a viable waste disposal option. Specifically, this concept of solar induced high-temperature photochemistry is based on the synergistic contribution of concentrated infrared (IR) radiation, which acts as an intense heating source, and near ultraviolet and visible (UV-VIS) radiation, which can induce destructive photochemical processes. Some significant advances have been made in the theoretical framework of high-temperature photochemical processes (Section 2) and development of experimental techniques for their study (Section 3). Basic thermal/photolytic studies have addressed the effect of temperature on the photochemical destruction of pure compounds (Section 4). Detailed studies of the destruction of reaction by-products have been conducted on selected waste molecules (Section 5). Some very limited results are available on the destruction of mixtures (Section 6). Fundamental spectroscopic studies have been recently initiated (Section 7). The results to date have been used to conduct some relatively simple scale-up studies of the solar detoxification process. More recent work has focused on destruction of compounds that do not directly absorb solar radiation. Research efforts have focused on homogeneous as well as heterogeneous methods of initiating destructive reaction pathways (Section 9). Although many conclusions at this point must be considered tentative due to lack of basic research, a clearer picture of the overall process is emerging (Section 10). However, much research remains to be performed and most follow several veins, including photochemical, spectroscopic, combustion kinetic, and engineering scale-up (Section 11).

  16. Temperature dependence of thermal conductivity of biological tissues.

    Science.gov (United States)

    Bhattacharya, A; Mahajan, R L

    2003-08-01

    In this paper, we present our experimental results on the determination of the thermal conductivity of biological tissues using a transient technique based on the principles of the cylindrical hot-wire method. A novel, 1.45 mm diameter, 50 mm long hot-wire probe was deployed. Initial measurements were made on sponge, gelatin and Styrofoam insulation to test the accuracy of the probe. Subsequent experiments conducted on sheep collagen in the range of 25 degrees C thermal conductivity to be a linear function of temperature. Further, these changes in the thermal conductivity were found to be reversible. However, when the tissue was heated beyond 55 degrees C, irreversible changes in thermal conductivity were observed. Similar experiments were also conducted for determining the thermal conductivity of cow liver. In this case, the irreversible effects were found to set in much later at around 90 degrees C. Below this temperature, in the range of 25 degrees C thermal conductivity, as for sheep collagen, varied linearly with temperature. In the second part of our study, in vivo measurements were taken on the different organs of a living pig. Comparison with reported values for dead tissues shows the thermal conductivities of living organs to be higher, indicating thereby the dominant role played by blood perfusion in enhancing the net heat transfer in living tissues. The degree of enhancement is different in different organs and shows a direct dependence on the blood flow rate.

  17. Thermal properties of SFR-HPC exposed to high temperatures

    Science.gov (United States)

    Scheinherrová, Lenka; Pavlík, Zbyšek

    2017-07-01

    In this paper, a non-adiabatic method was used for the assessment of specific heat capacity of steel fibre reinforced high performance concrete in the temperature range 105-1000 °C. The tested SFR-HPC mix was produced from CEM II 42.5 R, ground granulated blast furnace slag, silica sand with maximum particle size of 2 mm, silica fume, brass-coated steel fibres, superplasticizer on polycarboxylate ether basis and batch water. For the studied material, properties after 2 hours thermal treatment at the temperatures of 105 °C, 200 °C, 400 °C, 600 °C, 800 °C, and 1000 °C respectively were tested. Among them, bulk density, matrix density, total open porosity and thermal parameters as thermal conductivity, thermal diffusivity and specific heat capacity were measured. The measured specific heat capacity exhibited high dependence on temperature and pointed to the structural changes that studied material underwent at high temperatures. Accordingly, the obtained residual parameters revealed the thermally induced damage of SFR-HPC and critical temperatures for its functionality.

  18. Efficient Solar-Thermal Energy Harvest Driven by Interfacial Plasmonic Heating-Assisted Evaporation.

    Science.gov (United States)

    Chang, Chao; Yang, Chao; Liu, Yanming; Tao, Peng; Song, Chengyi; Shang, Wen; Wu, Jianbo; Deng, Tao

    2016-09-07

    The plasmonic heating effect of noble nanoparticles has recently received tremendous attention for various important applications. Herein, we report the utilization of interfacial plasmonic heating-assisted evaporation for efficient and facile solar-thermal energy harvest. An airlaid paper-supported gold nanoparticle thin film was placed at the thermal energy conversion region within a sealed chamber to convert solar energy into thermal energy. The generated thermal energy instantly vaporizes the water underneath into hot vapors that quickly diffuse to the thermal energy release region of the chamber to condense into liquids and release the collected thermal energy. The condensed water automatically flows back to the thermal energy conversion region under the capillary force from the hydrophilic copper mesh. Such an approach simultaneously realizes efficient solar-to-thermal energy conversion and rapid transportation of converted thermal energy to target application terminals. Compared to conventional external photothermal conversion design, the solar-thermal harvesting device driven by the internal plasmonic heating effect has reduced the overall thermal resistance by more than 50% and has demonstrated more than 25% improvement of solar water heating efficiency.

  19. Evaluation of solar thermal storages with quantitative flow visualisation

    Energy Technology Data Exchange (ETDEWEB)

    Logie, W.; Frank, E.; Luzzi, A.

    2008-07-15

    The non-intrusive Quantitative Flow Visualisation (QFV) Techniques of Particle Imaging Velocimetry (PIV) and Laser Induced Fluorescence (LIF) have been evaluated in the context of experimental investigations on solar Thermal Energy Storages (TES). Much competence and experience has been gained in the integration of these powerful yet complex and time consuming flow analysis methods into the realm of laboratory experimentation. In addition to gathering experience in the application of QFV techniques, a number of charging and discharging variations were considered in light of exergetic evaluation for the influence they have on the ability of a TES to stratify. The contemporary awareness that poorly chosen pitch to diameter ratios by the design of immersed coil heat exchangers leads to a reduction in heat exchange and an increase in mixing phenomenon has been confirmed. The observation of two combitank (combined domestic hot water and space heating) configurations has shown that free convective heat transfer forces in the form of mixing energy play a significant role in the stratification efficiency of thermal energy storages. (author)

  20. Kinetic instabilities in the solar wind driven by temperature anisotropies

    Science.gov (United States)

    Yoon, Peter H.

    2017-12-01

    The present paper comprises a review of kinetic instabilities that may be operative in the solar wind, and how they influence the dynamics thereof. The review is limited to collective plasma instabilities driven by the temperature anisotropies. To limit the scope even further, the discussion is restricted to the temperature anisotropy-driven instabilities within the model of bi-Maxwellian plasma velocity distribution function. The effects of multiple particle species or the influence of field-aligned drift will not be included. The field-aligned drift or beam is particularly prominent for the solar wind electrons, and thus ignoring its effect leaves out a vast portion of important physics. Nevertheless, for the sake of limiting the scope, this effect will not be discussed. The exposition is within the context of linear and quasilinear Vlasov kinetic theories. The discussion does not cover either computer simulations or data analyses of observations, in any systematic manner, although references will be made to published works pertaining to these methods. The scientific rationale for the present analysis is that the anisotropic temperatures associated with charged particles are pervasively detected in the solar wind, and it is one of the key contemporary scientific research topics to correctly characterize how such anisotropies are generated, maintained, and regulated in the solar wind. The present article aims to provide an up-to-date theoretical development on this research topic, largely based on the author's own work.

  1. Encapsulation of High Temperature Phase Change Materials for Thermal Energy Storage

    Science.gov (United States)

    Nath, Rupa

    Thermal energy storage is a major contributor to bridge the gap between energy demand (consumption) and energy production (supply) by concentrating solar power. The utilization of high latent heat storage capability of phase change materials is one of the keys to an efficient way to store thermal energy. However, some of the limitations of the existing technology are the high volumetric expansion and low thermal conductivity of phase change materials (PCMs), low energy density, low operation temperatures and high cost. The present work deals with encapsulated PCM system, which operates at temperatures above 500°C and takes advantage of the heat transfer modes at such high temperatures to overcome the aforementioned limitations of PCMs. Encapsulation with sodium silicate coating on preformed PCM pellets were investigated. A low cost, high temperature metal, carbon steel has been used as a capsule for PCMs with a melting point above 500° C. Sodium silicate and high temperature paints were used for oxidation protection of steel at high temperatures. The emissivity of the coatings to enhance heat transfer was investigated.

  2. Theoretical variations of the thermal performance of different solar collectors and solar combi systems as function of the varying yearly weather conditions in Denmark

    DEFF Research Database (Denmark)

    Andersen, Elsa; Furbo, Simon

    2009-01-01

    The thermal performances of solar collectors and solar combi systems with different solar fractions are studied under the influence of the Danish Design Reference Year, DRY data file, and measured weather data from a solar radiation measurement station situated at the Technical University...... collector or the annual global radiation. Solar combi systems with high efficient solar collectors are more influenced by weather variations from one year to another than systems with low efficient solar collectors. The annual thermal performance of solar collectors cannot be predicted from the global...

  3. Comparison of Thermal Performances of Fixed and Tracking Solar Collectors With Computational Fluid Dynamics

    OpenAIRE

    Keçel, Selçuk

    2015-01-01

    Solar collectors, one of the important areas of use for solar power, are based on the principle of heating water flowing through piping systems with solar radiation. Collectors are mostly fixed with various constructions on roofs of buildings, which provide hot water. Efficiency differences between fixed systems and tracking systems are generally compared over efficiencies of photovoltaic systems. As a different this study, the thermal analysis of solar collector systems to be installed on tw...

  4. Estimate of thermal fatigue lifetime for the INCONEL 625lCF plate while exposed to concentrated solar radiation

    Energy Technology Data Exchange (ETDEWEB)

    Rojas-Morin, A.; Fernandez-Reche, J.

    2011-07-01

    A system for testing the thermal cycling of materials and components has been developed and installed at the DISTAL-I parabolic dish facility located at the Plataforma Solar de Almeria (PSA) in Spain. This system allows us to perform abrupt heating/cooling tests by exposing central solar receiver materials to concentrated solar radiation. These tests are performed to simulate both the normal and critical operational conditions of the central solar receiver. The thermal fatigue life for the INCONEL 625LCF plate when subjected to concentrated solar radiation has been estimated with this system. We have also developed a numerical model that evaluates the thermal behavior of the plate material; additionally, the model yields the tensile-compressive stresses on the plate, which allow the estimation of the Stress-Life (S-N) fatigue curves. These curves show that the lifetime of the plate is within the High Cycle Fatigue (HCF) region at the operational temperatures of both 650 degree centigrade and 900 degree centigrade. (Author) 20 refs.

  5. Thermal contribution to the inactivation of Cryptosporidium in plastic bottles during solar water disinfection procedures.

    Science.gov (United States)

    Gómez-Couso, Hipólito; Fontán-Sainz, María; Ares-Mazás, Elvira

    2010-01-01

    To determine the thermal contribution, independent of ultraviolet radiation, on the inactivation of Cryptosporidium parvum during solar water disinfection procedures (SODIS), oocysts were exposed for 4, 8, and 12 hours to temperatures recorded in polyethylene terephthalate bottles in previous SODIS studies carried out under field conditions. Inclusion/exclusion of the fluorogenic vital dye propidium iodide, spontaneous excystation, and infectivity studies were used to determine the inactivation of oocysts. There was a significant increase in the percentage of oocysts that took up propidium iodide and in the number of oocysts that excysted spontaneously. There was also a significant decrease in the intensity of infection elicited in suckling mice at the end of all exposure times. The results of the study demonstrate the importance of temperature in the inactivation of C. parvum oocysts during application of SODIS under natural conditions.

  6. Modeling and Characteristic Analysis of a Solar Parabolic Trough System: Thermal Oil as the Heat Transfer Fluid

    Directory of Open Access Journals (Sweden)

    Zhai Rongrong

    2013-01-01

    Full Text Available The thermal oil is applied as the heat transfer fluid in a solar parabolic trough collector system. Firstly, the system dynamic model was established and validated by the real operating data in typical summer and spring days in references. Secondly, the alteration characteristics of different solar radiation, inlet water temperature and flow rate, and collectors’ area and length are analyzed and compared with the normal working condition. The model can be used for studying, system designing, and better understanding of the performance of parabolic trough systems.

  7. Damage Assessment of Stress-Thermal Cycled high temperature

    Science.gov (United States)

    Ju, Jae-Hyung; Prochazka, Michael; Ronke, Ben; Morgan, Roger; Shin, Eugence

    2004-01-01

    We report on the characterization of bismaleimide and polyimide carbon fiber composite, microcrack development under stress thermal cycling loading. Such cycles range from cryogenic temperatures associated with cryogenic fuel (LN, LOX) containment to high temperatures of 300 degrees Celsius associated with future hypervelocity aeropropulsion systems. Microcrack development thresholds as a function of temperature range of the thermal cycle; the number of cycles; the applied stress level imposed on the composite are reported. We have conducted stress-thermal cycles on thin bismaleimide-woven carbon fiber foils for three temperature range cycles: 1. Ambient temperature - -196 degrees celsius. 2. Ambient temperature - 150 degrees Celsius; 200 degrees Celsius; 250 degrees Celsius. 3. -196 degrees Celsius - 250 degrees Celsius. The Principle findings are that the full cycles from -196 degrees Celsius to to 250 degrees Celsius cause the most significant microcrack of development. These observations indicate that the high temperature portion of the cycle under load causes fiber-matrix interface failure and subsequent exposure to higher stresses at the cryogenic, low temperature region results in composite matrix microcracking as a result of the additional stresses associate with the fiber-matrix thermal expansion mismatch. Our initial studies for 12 ply PMR-II-50 polyimide/M60JB carbon fabric [0f,90f,90f,0f,0f,90f]ls composites will be presented. The stress-thermal cycle test procedure for these will be described. Moisture absorption characteristics between cycles will be used to monitor interconnected microcrack development. The applied stress level will be 75% of the composite cryogenic (-196 degrees Celsius) ultimate strength.

  8. Thermal properties of solids at room and cryogenic temperatures

    CERN Document Server

    Ventura, Guglielmo

    2014-01-01

    This book is a guide for materials scientists, physicists, chemists and engineers who wish to explore the field of low-temperature material properties. The focus is on heat capacity, thermal expansion and electrical and thermal conductivity. The authors report a wide range of experimental details and data, and have compiled useful tables of low-temperature data. Each chapter of the book starts by addressing the theoretical basis of the phenomena. This is a concise presentation, but it helps the reader to develop a deeper understanding of the experiments. The second part of the chapters is dedicated to describing the main experimental techniques to measure thermal properties at low and very low temperature ranges. The final part of each chapter provides a wealth of relevant experimental data in the form of tables and graphs.

  9. An overview of water disinfection in developing countries and the potential for solar thermal water pasteurization

    Energy Technology Data Exchange (ETDEWEB)

    Burch, J.; Thomas, K.E.

    1998-01-01

    This study originated within the Solar Buildings Program at the U.S. Department of Energy. Its goal is to assess the potential for solar thermal water disinfection in developing countries. In order to assess solar thermal potential, the alternatives must be clearly understood and compared. The objectives of the study are to: (a) characterize the developing world disinfection needs and market; (b) identify competing technologies, both traditional and emerging; (c) analyze and characterize solar thermal pasteurization; (d) compare technologies on cost-effectiveness and appropriateness; and (e) identify research opportunities. Natural consequences of the study beyond these objectives include a broad knowledge of water disinfection problems and technologies, introduction of solar thermal pasteurization technologies to a broad audience, and general identification of disinfection opportunities for renewable technologies.

  10. Benefits of full scope simulators during solar thermal power plants design and construction

    Science.gov (United States)

    Gallego, José F.; Gil, Elena; Rey, Pablo

    2017-06-01

    In order to efficiently develop high-precision dynamic simulators for solar thermal power plants, Tecnatom adapted its simulation technology to consider solar thermal models. This effort and the excellent response of the simulation market have allowed Tecnatom to develop simulators with both parabolic trough and solar power tower technologies, including molten salt energy storage. These simulators may pursue different objectives, giving rise to training or engineering simulators. Solar thermal power market combines the need for the training of the operators with the potential benefits associated to the improvement of the design of the plants. This fact along with the simulation capabilities enabled by the current technology and the broad experience of Tecnatom present the development of an engineering+training simulator as a very advantageous option. This paper describes the challenge of the development and integration of a full scope simulator during the design and construction stages of a solar thermal power plant, showing the added value to the different engineering areas.

  11. Experimental Investigation of Latent Heat Thermal Energy Storage for Bi-Modal Solar Thermal Propulsion (Briefing Charts)

    Science.gov (United States)

    2014-07-01

    performance of 28,100 kg, shuttle launched spacecraft for LEO-GEO transfer Engine Type LO2-H2 Ion Solar 1 Solar 2 ΔV (m/s) 4,270 5,850 5,850 4,800...Comparison Metrics Solar Thermal w/o Energy Storage Chemical Thrusters Electric Propulsion • Eliminated PCM and TPV • Reduced solar collector ...currently valid OMB control number. PLEASE DO NOT RETURN YOUR FORM TO THE ABOVE ADDRESS. 1. REPORT DATE (DD-MM-YYYY) July 2014 2. REPORT TYPE Briefing

  12. A Mathematical Model for the Temperature Field in the Absorber of a New Type Solar Collector

    National Research Council Canada - National Science Library

    P Shipkov; V Barkans; M van ags; L Vasilevska

    2010-01-01

      A Mathematical Model for the Temperature Field in the Absorber of a New Type Solar Collector The temperature field problem described in the paper is analytically solved for the absorber of a new type solar collector...

  13. A low cost high temperature sun tracking solar energy collector

    Science.gov (United States)

    Perkins, G. S.

    1977-01-01

    The design and economic evaluation of a low cost high temperature two axis sun tracking solar energy collector are described. The collector design is specifically intended for solar energy use with the freedom of motion about its two control axes being limited only to the amplitude required to track the sun. An examination of the performance criteria required in order to track the sun and perform the desired solar energy conversion is used as the starting point and guide to the design. This factor, along with its general configuration and structural aspect ratios, is the significant contributor to achieving low cost. The unique mechanical design allows the control system to counter wide tolerances that will be specified for the fabrication of the azimuth frame and perform within a small tracking error.

  14. Solar thermal power plants in small utilities - An economic impact analysis

    Science.gov (United States)

    Bluhm, S. A.; Ferber, R. R.; Mayo, L. G.

    1979-01-01

    A study was performed to assess the potential economic impact of small solar thermal electric power systems in statistically representative synthetic small utilities of the Southwestern United States. Power supply expansion plans were compared on the basis of present worth of future revenue requirements for 1980-2000 with and without solar thermal plants. Coal-fired and oil-fired municipal utility expansion plans with 5 percent solar penetration were 0.5 percent and 2.25 percent less expensive, respectively, than the corresponding conventional plan. At $969/kWe, which assumes the same low cost solar equipment but no improvement in site development costs, solar penetration of 5 percent in the oil-fired municipal reduced revenue requirements 0.88 percent. The paper concludes that some solar thermal plants are potentially economic in small community utilities of the Southwest.

  15. Renewable Electricity Generation via Solar-Powered Methanol Reforming: Hybrid Proton Exchange Membrane Fuel Cell Systems Based on Novel Non-Concentrating, Intermediate-Temperature Solar Collectors

    Science.gov (United States)

    Real, Daniel J.

    Tremendous research efforts have been conducted studying the capturing and conversion of solar energy. Solar thermal power systems offer a compelling opportunity for renewable energy utilization with high efficiencies and excellent cost-effectiveness. The goal of this work was to design a non-concentrating collector capable of reaching temperatures above 250 °C, use this collector to power methanol steam reforming, and operate a proton exchange membrane (PEM) fuel cell using the generated hydrogen. The study presents the construction and characterization of a non-concentrating, intermediate-temperature, fin-in-tube evacuated solar collector, made of copper and capable of reaching stagnation temperatures of 268.5 °C at 1000 W/m2 irradiance. The collector was used to power methanol steam reforming, including the initial heating and vaporization of liquid reactants and the final heating of the gaseous reactants. A preferential oxidation (PROX) catalyst was used to remove CO from simulated reformate gas, and this product gas was used to operate a PEM fuel cell. The results show 1) that the outlet temperature is not limited by heat transfer from the absorber coating to the heat transfer fluid, but by the amount of solar energy absorbed. This implicates a constant heat flux description of the heat transfer process and allows for the usage of materials with lower thermal conductivity than copper. 2) It is possible to operate a PEM fuel cell from reformate gas if a PROX catalyst is used to remove CO from the gas. 3) The performance of the fuel cell is only slightly decreased (~4%) by CO2 dilution present in the reformate and PROX gas. These results provide a foundation for the first renewable electricity generation via solar-powered methanol reforming through a hybrid PEM fuel cell system based on novel non-concentrating, intermediate-temperature solar collectors.

  16. Efficiency of tandem solar cell systems as function of temperature and solar energy concentration ratio

    Science.gov (United States)

    Gokcen, N. A.; Loferski, J. J.

    1979-01-01

    The results of a comprehensive theoretical analysis of tandem photovoltaic solar cells as a function of temperature and solar concentration ratio are presented. The overall efficiencies of tandem cell stacks consisting of as many as 24 cells having gaps in the 0.7 to 3.6 eV range were calculated for temperatures of 200, 300, 400, and 500 K and for illumination by an AMO solar spectrum having concentration ratios of 1, 100, 500, and 1000 suns. For ideal diodes (A = B = 1), the calculations show that the optimized overall efficiency has a limiting value eta sub opt of approximately 70 percent for T = 200 K and C = 1000; for T = 300 K and C = 1000, this limiting efficiency approaches 60 percent.

  17. Room temperature screening of thermal conductivity by means of thermal transient measurements

    Science.gov (United States)

    García-Cañadas, Jorge; Cheng, Shudan; Márquez-García, Lourdes; Prest, Martin J.; Akbari-Rahimabadi, Ahmad; Min, Gao

    2016-10-01

    A proof of concept of the possibility to estimate thermal conductivity of bulk disc samples at room temperature by means of thermal decays is demonstrated. An experimental set-up was designed and fabricated, which is able to perform thermal transient measurements by using a specially designed multifunctional probe that has the ability to measure temperature at its tip. Initially, the probe is heated by a heater coil located in its interior until the tip temperature reaches a steady state. Then, the probe is contacted with a disc sample which produces a temperature decay until a new state is reached. The difference between the initial and final states temperatures shows a correlation with the thermal conductivity of the sample. Employing a calibration equation, obtained using reference materials, the thermal conductivity can be calculated. Reasonably good random and systematic errors (<13% and ~9% respectively) are obtained. Theoretical simulations performed using COMSOL show a good qualitative agreement with experimental results. This new method involves an inexpensive and simple set-up which can be especially useful for thermal conductivity screening and high-throughput measurements.

  18. Prediction of global solar irradiance based on time series analysis: Application to solar thermal power plants energy production planning

    Energy Technology Data Exchange (ETDEWEB)

    Martin, Luis; Marchante, Ruth; Cony, Marco [Investigaciones y Recursos Solares Avanzados (IrSOLaV), Tres Cantos 2 8045 (Spain); Zarzalejo, Luis F.; Polo, Jesus; Navarro, Ana [Energy Department, CIEMAT, Madrid 28040 (Spain)

    2010-10-15

    Due to strong increase of solar power generation, the predictions of incoming solar energy are acquiring more importance. Photovoltaic and solar thermal are the main sources of electricity generation from solar energy. In the case of solar thermal energy plants with storage energy system, its management and operation need reliable predictions of solar irradiance with the same temporal resolution as the temporal capacity of the back-up system. These plants can work like a conventional power plant and compete in the energy stock market avoiding intermittence in electricity production. This work presents a comparisons of statistical models based on time series applied to predict half daily values of global solar irradiance with a temporal horizon of 3 days. Half daily values consist of accumulated hourly global solar irradiance from solar raise to solar noon and from noon until dawn for each day. The dataset of ground solar radiation used belongs to stations of Spanish National Weather Service (AEMet). The models tested are autoregressive, neural networks and fuzzy logic models. Due to the fact that half daily solar irradiance time series is non-stationary, it has been necessary to transform it to two new stationary variables (clearness index and lost component) which are used as input of the predictive models. Improvement in terms of RMSD of the models essayed is compared against the model based on persistence. The validation process shows that all models essayed improve persistence. The best approach to forecast half daily values of solar irradiance is neural network models with lost component as input, except Lerida station where models based on clearness index have less uncertainty because this magnitude has a linear behaviour and it is easier to simulate by models. (author)

  19. Instrument for Measuring Thermal Conductivity of Materials at Low Temperatures

    Science.gov (United States)

    Fesmire, James; Sass, Jared; Johnson, Wesley

    2010-01-01

    With the advance of polymer and other non-metallic material sciences, whole new series of polymeric materials and composites are being created. These materials are being optimized for many different applications including cryogenic and low-temperature industrial processes. Engineers need these data to perform detailed system designs and enable new design possibilities for improved control, reliability, and efficiency in specific applications. One main area of interest is cryogenic structural elements and fluid handling components and other parts, films, and coatings for low-temperature application. An important thermal property of these new materials is the apparent thermal conductivity (k-value).

  20. High-temperature plasmonic thermal emitter for thermophotovotaics

    DEFF Research Database (Denmark)

    Liu, Jingjing; Guler, Urcan; Li, Wei

    2014-01-01

    We use titanium nitride (TiN) to demonstrate an ultra-thin plasmonic thermal emitter operating at high temperatures (830 K). The spectrally selective emitter exhibits a large emittance at around 2.5 μm and below, and suppresses emission at longer wavelengths.......We use titanium nitride (TiN) to demonstrate an ultra-thin plasmonic thermal emitter operating at high temperatures (830 K). The spectrally selective emitter exhibits a large emittance at around 2.5 μm and below, and suppresses emission at longer wavelengths....

  1. Evaluation of thermal control coatings for use on solar dynamic radiators in low earth orbit

    Science.gov (United States)

    Dever, Joyce A.; Rodriguez, Elvin; Slemp, Wayne S.; Stoyack, Joseph E.

    1991-01-01

    Thermal control coatings with high thermal emittance and low solar absorptance are needed for Space Station Freedom (SSF) solar dynamic power module radiator (SDR) surfaces for efficient heat rejection. Additionally, these coatings must be durable to low earth orbital (LEO) environmental effects of atomic oxygen, ultraviolet radiation and deep thermal cycles which occur as a result of start-up and shut-down of the solar dynamic power system. Eleven candidate coatings were characterized for their solar absorptance and emittance before and after exposure to ultraviolet (UV) radiation (200 to 400 nm), vacuum UV (VUV) radiation (100 to 200 nm) and atomic oxygen. Results indicated that the most durable and best performing coatings were white paint thermal control coatings Z-93, zinc oxide pigment in potassium silicate binder, and YB-71, zinc orthotitanate pigment in potassium silicate binder. Optical micrographs of these materials exposed to the individual environmental effects of atomic oxygen and vacuum thermal cycling showed that no surface cracking occurred.

  2. Energy efficiency and comfort conditions in passive solar buildings: Effect of thermal mass at equatorial high altitudes

    Science.gov (United States)

    Ogoli, David Mwale

    This dissertation is based on the philosophy that architectural design should not just be a function of aesthetics, but also of energy-efficiency, advanced technologies and passive solar strategies. A lot of published literature is silent regarding buildings in equatorial highland regions. This dissertation is part of the body of knowledge that attempts to provide a study of energy in buildings using thermal mass. The objectives were to establish (1) effect of equatorial high-altitude climate on thermal mass, (2) effect of thermal mass on moderating indoor temperatures, (3) effect of thermal mass in reducing heating and cooling energy, and (4) the amount of time lag and decrement factor of thermal mass. Evidence to analyze the effect of thermal mass issues came from three sources. First, experimental physical models involving four houses were parametrically conducted in Nairobi, Kenya. Second, energy computations were made using variations in thermal mass for determining annual energy usage and costs. Third, the data gathered were observed, evaluated, and compared with currently published research. The findings showed that: (1) Equatorial high-altitude climates that have diurnal temperature ranging about 10--15°C allow thermal mass to moderate indoor temperatures; (2) Several equations were established that indicate that indoor mean radiant temperatures can be predicted from outdoor temperatures; (3) Thermal mass can reduce annual energy for heating and cooling by about 71%; (4) Time lag and decrement of 200mm thick stone and concrete thermal mass can be predicted by a new formula; (5) All windows on a building should be shaded. East and west windows when shaded save 51% of the cooling energy. North and south windows when fully shaded account for a further 26% of the cooling energy; (6) Insulation on the outside of a wall reduces energy use by about 19.6% below the levels with insulation on the inside. The basic premise of this dissertation is that decisions that

  3. Surface reflectance drives nest box temperature profiles and thermal suitability for target wildlife.

    Directory of Open Access Journals (Sweden)

    Stephen R Griffiths

    Full Text Available Thermal properties of tree hollows play a major role in survival and reproduction of hollow-dependent fauna. Artificial hollows (nest boxes are increasingly being used to supplement the loss of natural hollows; however, the factors that drive nest box thermal profiles have received surprisingly little attention. We investigated how differences in surface reflectance influenced temperature profiles of nest boxes painted three different colors (dark-green, light-green, and white: total solar reflectance 5.9%, 64.4%, and 90.3% respectively using boxes designed for three groups of mammals: insectivorous bats, marsupial gliders and brushtail possums. Across the three different box designs, dark-green (low reflectance boxes experienced the highest average and maximum daytime temperatures, had the greatest magnitude of variation in daytime temperatures within the box, and were consistently substantially warmer than light-green boxes (medium reflectance, white boxes (high reflectance, and ambient air temperatures. Results from biophysical model simulations demonstrated that variation in diurnal temperature profiles generated by painting boxes either high or low reflectance colors could have significant ecophysiological consequences for animals occupying boxes, with animals in dark-green boxes at high risk of acute heat-stress and dehydration during extreme heat events. Conversely in cold weather, our modelling indicated that there are higher cumulative energy costs for mammals, particularly smaller animals, occupying light-green boxes. Given their widespread use as a conservation tool, we suggest that before boxes are installed, consideration should be given to the effect of color on nest box temperature profiles, and the resultant thermal suitability of boxes for wildlife, particularly during extremes in weather. Managers of nest box programs should consider using several different colors and installing boxes across a range of both orientations and

  4. Surface reflectance drives nest box temperature profiles and thermal suitability for target wildlife.

    Science.gov (United States)

    Griffiths, Stephen R; Rowland, Jessica A; Briscoe, Natalie J; Lentini, Pia E; Handasyde, Kathrine A; Lumsden, Linda F; Robert, Kylie A

    2017-01-01

    Thermal properties of tree hollows play a major role in survival and reproduction of hollow-dependent fauna. Artificial hollows (nest boxes) are increasingly being used to supplement the loss of natural hollows; however, the factors that drive nest box thermal profiles have received surprisingly little attention. We investigated how differences in surface reflectance influenced temperature profiles of nest boxes painted three different colors (dark-green, light-green, and white: total solar reflectance 5.9%, 64.4%, and 90.3% respectively) using boxes designed for three groups of mammals: insectivorous bats, marsupial gliders and brushtail possums. Across the three different box designs, dark-green (low reflectance) boxes experienced the highest average and maximum daytime temperatures, had the greatest magnitude of variation in daytime temperatures within the box, and were consistently substantially warmer than light-green boxes (medium reflectance), white boxes (high reflectance), and ambient air temperatures. Results from biophysical model simulations demonstrated that variation in diurnal temperature profiles generated by painting boxes either high or low reflectance colors could have significant ecophysiological consequences for animals occupying boxes, with animals in dark-green boxes at high risk of acute heat-stress and dehydration during extreme heat events. Conversely in cold weather, our modelling indicated that there are higher cumulative energy costs for mammals, particularly smaller animals, occupying light-green boxes. Given their widespread use as a conservation tool, we suggest that before boxes are installed, consideration should be given to the effect of color on nest box temperature profiles, and the resultant thermal suitability of boxes for wildlife, particularly during extremes in weather. Managers of nest box programs should consider using several different colors and installing boxes across a range of both orientations and shade profiles (i

  5. Surface reflectance drives nest box temperature profiles and thermal suitability for target wildlife

    Science.gov (United States)

    Rowland, Jessica A.; Briscoe, Natalie J.; Lentini, Pia E.; Handasyde, Kathrine A.; Lumsden, Linda F.; Robert, Kylie A.

    2017-01-01

    Thermal properties of tree hollows play a major role in survival and reproduction of hollow-dependent fauna. Artificial hollows (nest boxes) are increasingly being used to supplement the loss of natural hollows; however, the factors that drive nest box thermal profiles have received surprisingly little attention. We investigated how differences in surface reflectance influenced temperature profiles of nest boxes painted three different colors (dark-green, light-green, and white: total solar reflectance 5.9%, 64.4%, and 90.3% respectively) using boxes designed for three groups of mammals: insectivorous bats, marsupial gliders and brushtail possums. Across the three different box designs, dark-green (low reflectance) boxes experienced the highest average and maximum daytime temperatures, had the greatest magnitude of variation in daytime temperatures within the box, and were consistently substantially warmer than light-green boxes (medium reflectance), white boxes (high reflectance), and ambient air temperatures. Results from biophysical model simulations demonstrated that variation in diurnal temperature profiles generated by painting boxes either high or low reflectance colors could have significant ecophysiological consequences for animals occupying boxes, with animals in dark-green boxes at high risk of acute heat-stress and dehydration during extreme heat events. Conversely in cold weather, our modelling indicated that there are higher cumulative energy costs for mammals, particularly smaller animals, occupying light-green boxes. Given their widespread use as a conservation tool, we suggest that before boxes are installed, consideration should be given to the effect of color on nest box temperature profiles, and the resultant thermal suitability of boxes for wildlife, particularly during extremes in weather. Managers of nest box programs should consider using several different colors and installing boxes across a range of both orientations and shade profiles (i

  6. Temperature distributions in trapezoidal built in storage solar water heaters with/without phase change materials

    Energy Technology Data Exchange (ETDEWEB)

    Tarhan, Sefa; Yardim, M. Hakan [Department of Farm Machinery, Faculty of Agriculture, Gaziosmanpasa University, Tasliciftlik Yerleskesi, 60240 Tokat (Turkey); Sari, Ahmet [Department of Chemistry, Faculty of Arts and Sciences, Gaziosmanpasa University, Tasliciftlik Yerleskesi, 60240 Tokat (Turkey)

    2006-09-15

    Built in storage solar water heaters (BSSWHs) have been recognized for their more compact constructions and faster solar gain than conventional solar water heaters, however, their water temperatures quickly go down during the cooling period. A trapezoidal BSSWH without PCM storage unit was used as the control heater (reference) to investigate the effect of two differently configured PCM storage units on the temperature distributions in water tanks. In the first design, myristic acid was filled into the PCM storage tank, which also served as an absorbing plate. In the second design, lauric acid was filled into the PCM storage tank, which also served as a baffle plate. The water temperature changes were followed by five thermocouples placed evenly and longitudinally into each of the three BSSWHs. The effects of the PCMs on the water temperature distributions depended on the configuration of the PCM storage unit and the longitudinal position in the water tanks. The use of lauric acid lowered the values of the peak temperatures by 15% compared to the control heater at the upper portion of the water tanks because of the low melting temperature of lauric acid, but it did not have any consistent effect on the retention of the water temperatures during the cooling period. The ability of the myristic acid storage unit to retain the water temperatures got more remarkable, especially at the middle portion of the water tank. The myristic acid storage increased the dip temperatures by approximately 8.8% compared to the control heater. In conclusion, lauric acid storage can be used to stabilize the water temperature during the day time, while the myristic acid storage unit can be used as a thermal barrier against heat loss during the night time because of its relatively high melting temperature and low heat conduction coefficient in its solid phase. The experimental results have also indicated that the thermal characteristics of the PCM and the configuration of the PCM storage

  7. Improved Thermal-Insulation Systems for Low Temperatures

    Science.gov (United States)

    Fesmire, James E.; Augustynowicz, Stanislaw D.

    2003-01-01

    Improved thermal-insulation materials and structures and the techniques for manufacturing them are undergoing development for use in low-temperature applications. Examples of low-temperature equipment for which these thermal insulation systems could provide improved energy efficiency include storage tanks for cryogens, superconducting electric-power-transmission equipment, containers for transport of food and other perishable commodities, and cold boxes for low-temperature industrial processes. These systems could also be used to insulate piping used to transfer cryogens and other fluids, such as liquefied natural gas, refrigerants, chilled water, crude oil, or low-pressure steam. The present thermal-insulation systems are layer composites based partly on the older class of thermal-insulation systems denoted generally as multilayer insulation (MLI). A typical MLI structure includes an evacuated jacket, within which many layers of radiation shields are stacked or wrapped close together. Low-thermal-conductivity spacers are typically placed between the reflection layers to keep them from touching. MLI can work very well when a high vacuum level (less than 10(exp-4) torr) is maintained and utmost care is taken during installation, but its thermal performance deteriorates sharply as the pressure in the evacuated space rises into the soft vacuum range [pressures greater than 0.1 torr (greater than 13 Pa)]. In addition, the thermal performance of MLI is extremely sensitive to mechanical compression and edge effects and can easily decrease from one to two orders of magnitude from its ideal value even when the MLI is kept under high vacuum condition. The present thermal-insulation systems are designed to perform well under soft vacuum level, in particular the range of 1 to 10 torr. They are also designed with larger interlayer spacings to reduce vulnerability to compression (and consequent heat leak) caused by installation and use. The superiority of these systems is the

  8. A neural network based intelligent predictive sensor for cloudiness, solar radiation and air temperature.

    Science.gov (United States)

    Ferreira, Pedro M; Gomes, João M; Martins, Igor A C; Ruano, António E

    2012-11-12

    Accurate measurements of global solar radiation and atmospheric temperature,as well as the availability of the predictions of their evolution over time, are important for different areas of applications, such as agriculture, renewable energy and energy management, or thermal comfort in buildings. For this reason, an intelligent, light-weight and portable sensor was developed, using artificial neural network models as the time-series predictor mechanisms. These have been identified with the aid of a procedure based on the multi-objective genetic algorithm. As cloudiness is the most significant factor affecting the solar radiation reaching a particular location on the Earth surface, it has great impact on the performance of predictive solar radiation models for that location. This work also represents one step towards the improvement of such models by using ground-to-sky hemispherical colour digital images as a means to estimate cloudiness by the fraction of visible sky corresponding to clouds and to clear sky. The implementation of predictive models in the prototype has been validated and the system is able to function reliably, providing measurements and four-hour forecasts of cloudiness, solar radiation and air temperature.

  9. A Neural Network Based Intelligent Predictive Sensor for Cloudiness, Solar Radiation and Air Temperature

    Science.gov (United States)

    Ferreira, Pedro M.; Gomes, João M.; Martins, Igor A. C.; Ruano, António E.

    2012-01-01

    Accurate measurements of global solar radiation and atmospheric temperature, as well as the availability of the predictions of their evolution over time, are important for different areas of applications, such as agriculture, renewable energy and energy management, or thermal comfort in buildings. For this reason, an intelligent, light-weight and portable sensor was developed, using artificial neural network models as the time-series predictor mechanisms. These have been identified with the aid of a procedure based on the multi-objective genetic algorithm. As cloudiness is the most significant factor affecting the solar radiation reaching a particular location on the Earth surface, it has great impact on the performance of predictive solar radiation models for that location. This work also represents one step towards the improvement of such models by using ground-to-sky hemispherical colour digital images as a means to estimate cloudiness by the fraction of visible sky corresponding to clouds and to clear sky. The implementation of predictive models in the prototype has been validated and the system is able to function reliably, providing measurements and four-hour forecasts of cloudiness, solar radiation and air temperature. PMID:23202230

  10. A method for accurate temperature measurement using infrared thermal camera.

    Science.gov (United States)

    Tokunaga, Tomoharu; Narushima, Takashi; Yonezawa, Tetsu; Sudo, Takayuki; Okubo, Shuichi; Komatsubara, Shigeyuki; Sasaki, Katsuhiro; Yamamoto, Takahisa

    2012-08-01

    The temperature distribution on a centre-holed thin foil of molybdenum, used as a sample and heated using a sample-heating holder for electron microscopy, was measured using an infrared thermal camera. The temperature on the heated foil area located near the heating stage of the heating holder is almost equal to the temperature on the heating stage. However, during the measurement of the temperature at the edge of the hole of the foil located farthest from the heating stage, a drop in temperature should be taken into consideration; however, so far, no method has been developed to locally measure the temperature distribution on the heated sample. In this study, a method for the accurate measurement of temperature distribution on heated samples for electron microscopy is discussed.

  11. A fiber Bragg grating--bimetal temperature sensor for solar panel inverters.

    Science.gov (United States)

    Ismail, Mohd Afiq; Tamchek, Nizam; Hassan, Muhammad Rosdi Abu; Dambul, Katrina D; Selvaraj, Jeyrai; Rahim, Nasrudin Abd; Sandoghchi, Reza; Adikan, Faisal Rafiq Mahamd

    2011-01-01

    This paper reports the design, characterization and implementation of a fiber Bragg grating (FBG)-based temperature sensor for an insulted-gate Bipolar transistor (IGBT) in a solar panel inverter. The FBG is bonded to the higher coefficient of thermal expansion (CTE) side of a bimetallic strip to increase its sensitivity. Characterization results show a linear relationship between increasing temperature and the wavelength shift. It is found that the sensitivity of the sensor can be categorized into three characterization temperature regions between 26 °C and 90 °C. The region from 41 °C to 90 °C shows the highest sensitivity, with a value of 14 pm/°C. A new empirical model that considers both temperature and strain effects has been developed for the sensor. Finally, the FBG-bimetal temperature sensor is placed in a solar panel inverter and results confirm that it can be used for real-time monitoring of the IGBT temperature.

  12. Evaluation and Error Analysis for a Solar thermal Receiver

    Energy Technology Data Exchange (ETDEWEB)

    Pfander, M.

    2001-07-01

    In the following study a complete balance over the REFOS receiver module, mounted on the tower power plant CESA-1 at the Plataforma Solar de Almeria (PSA), is carried out. Additionally an error inspection of the various measurement techniques used in the REFOS project is made. Especially the flux measurement system Prohermes that is used to determine the total entry power of the receiver module and known as a major error source is analysed in detail. Simulations and experiments on the particular instruments are used to determine and quantify possible error sources. After discovering the origin of the errors they are reduced and included in the error calculation. the ultimate result is presented as an overall efficiency of the receiver module in dependence on the flux density at the receiver module's entry plane and the receiver operating temperature. (Author) 26 refs.

  13. Analysis of Thermal Radiation Effects on Temperatures in Turbine Engine Thermal Barrier Coatings

    Science.gov (United States)

    Siegel, Robert; Spuckler, Charles M.

    1998-01-01

    Thermal barrier coatings are important, and in some instances a necessity, for high temperature applications such as combustor liners, and turbine vanes and rotating blades for current and advanced turbine engines. Some of the insulating materials used for coatings, such as zirconia that currently has widespread use, are partially transparent to thermal radiation. A translucent coating permits energy to be transported internally by radiation, thereby increasing the total energy transfer and acting like an increase in thermal conductivity. This degrades the insulating ability of the coating. Because of the strong dependence of radiant emission on temperature, internal radiative transfer effects are increased as temperatures are raised. Hence evaluating the significance of internal radiation is of importance as temperatures are increased to obtain higher efficiencies in advanced engines.

  14. High efficiency thermal storage system for solar plants (HELSOLAR). Final report

    Energy Technology Data Exchange (ETDEWEB)

    Villarroel, Eduardo; Fernandez-Pello, Carlos; Lenartz, Jeff; Parysek, Karen

    2013-02-27

    The project objective was to develop a high temperature Thermal Storage System (TES) based on graphite and able to provide both economical and technical advantages with respect to existing solutions contributing to increase the share of Concentrated Solar Plants (CSP). One of the main disadvantages of most of the renewable energy systems is their dependence to instantaneous irradiation and, thus, lack of predictability. CSP plants with thermal storage have proved to offer a good solution to this problem although still at an elevated price. The identification of alternative concepts able to work more efficiently would help to speed up the convergence of CSP towards grid parity. One way to reduce costs is to work in a range of temperatures higher than those allowed by the actual molten salt systems, currently the benchmark for TES in CSP. This requires the use of alternative energy storage materials such as graphite, as well as the utilization of Heat Transfer Fluids (HTF) other than molten salts or organic oils. The main technical challenges identified are derived from the high temperatures and significant high pressures, which pose risks such as potential graphite and insulation oxidation, creep, fatigue, corrosion and stress-corrosion in the pipes, leakages in the joints, high blower drivers’ electrical power consumption, thermal compatibility or relative deformations of the different materials. At the end, the main challenge of the project, is to identify a technical solution able to overcome all these problems but still at a competitive cost when compared to already existing thermal storage solutions. Special attention is given to all these issues during this project.

  15. The Solar Thermal Design Assistance Center report of its activities and accomplishments in Fiscal Year 1993

    Energy Technology Data Exchange (ETDEWEB)

    Menicucci, D.F.

    1994-03-01

    The Solar Thermal Design Assistance Center (STDAC) at Sandia National Laboratories is a resource provided by the US Department of Energy`s Solar Thermal Program. Its major objectives are to accelerate the use of solar thermal systems through (a) direct technical assistance to users, (b) cooperative test, evaluation, and development efforts with private industry, and (c) educational outreach activities. This report outlines the major activities and accomplishments of the STDAC in Fiscal Year 1993. The report also contains a comprehensive list of persons who contacted the STDAC by telephone for information or technical consulting.

  16. Preliminary design of seawater and brackish water reverse osmosis desalination systems driven by low-temperature solar organic Rankine cycles (ORC)

    Energy Technology Data Exchange (ETDEWEB)

    Delgado-Torres, Agustin M. [Dpto. Fisica Fundamental y Experimental, Electronica y Sistemas, Escuela Tecnica Superior de Ingenieria Civil e Industrial, Universidad de La Laguna (ULL), Avda. Astrofisico Francisco Sanchez s/n. 38206 La Laguna (Tenerife) (Spain); Garcia-Rodriguez, Lourdes [Dpto. Ingenieria Energetica, Universidad de Sevilla Escuela Tecnica Superior de Ingenieros, Camino de los Descubrimientos, s/n 41092 Sevilla (Spain)

    2010-12-15

    In this paper, the coupling between the low-temperature solar organic Rankine cycle (ORC) and seawater and brackish water reverse osmosis desalination units has been carried out. Four substances have been considered as working fluids of the solar cycle (butane, isopentane, R245fa and R245ca). With these four fluids the volumetric flow of fresh water produced per unit of aperture area of stationary solar collector has been calculated. The former has been made with the optimized direct vapour generation (DVG) configuration and heat transfer fluid (HTF) configuration of the solar ORC. In the first one (DVG), working fluid of the ORC is directly heated inside the absorber of the solar collector. In the second one (HTF), a fluid different than the working fluid of the ORC (water in this paper) is heated without phase change inside the absorber of the solar collector. Once this fluid has been heated it is carried towards a heat exchanger where it is cooled. Thermal energy delivered in this cooling process is transferred to the working fluid of the ORC. Influence of condensation temperature of the ORC and regeneration's process effectiveness over productivity of the system has also been analysed. Finally, parameters of several preliminary designs of the low-temperature solar thermal driven RO desalination are supplied. R245fa is chosen as working fluid of the ORC in these preliminary designs. The information of the proposed preliminary designs can also be used, i.e., for the assessment of the use of thermal energy rejected by the solar cycle. Overall analysis of the efficiency of the solar thermal driven RO desalination technology is given with the results presented in this paper and the results obtained with the medium temperature solar thermal RO desalination system presented by the authors in previous papers. This work has been carried out within the framework of the OSMOSOL and POWERSOL projects. (author)

  17. Temperature dependent current transport properties in Cu{sub 2}ZnSnS{sub 4} solar cells

    Energy Technology Data Exchange (ETDEWEB)

    Danilson, Mati, E-mail: mati.danilson@ttu.ee [Department of Materials Science, Tallinn University of Technology, Ehitajate tee 5, 19086 Tallinn (Estonia); Kask, Erkki, E-mail: erkki.kask@ttu.ee [Department of Physics, Tallinn University of Technology, Ehitajate tee 5, 19086 Tallinn (Estonia); Pokharel, Nikhil, E-mail: pokharel.nikhil@gmail.com [Department of Materials Science, Tallinn University of Technology, Ehitajate tee 5, 19086 Tallinn (Estonia); Department of Natural Sciences (Physics), Kathmandu University, PO Box 6250 Dhulikhel (Nepal); Grossberg, Maarja, E-mail: Maarja.Grossberg@ttu.ee [Department of Materials Science, Tallinn University of Technology, Ehitajate tee 5, 19086 Tallinn (Estonia); Kauk-Kuusik, Marit, E-mail: marit.kauk-kuusik@ttu.ee [Department of Materials Science, Tallinn University of Technology, Ehitajate tee 5, 19086 Tallinn (Estonia); Varema, Tiit, E-mail: Tiit.Varema@ttu.ee [Department of Materials Science, Tallinn University of Technology, Ehitajate tee 5, 19086 Tallinn (Estonia); Krustok, Jüri, E-mail: juri.krustok@ttu.ee [Department of Materials Science, Tallinn University of Technology, Ehitajate tee 5, 19086 Tallinn (Estonia); Department of Physics, Tallinn University of Technology, Ehitajate tee 5, 19086 Tallinn (Estonia)

    2015-05-01

    Quaternary semiconductor compound Cu{sub 2}ZnSnS{sub 4} (CZTS) is a promising non-toxic absorber material for solar cells made from earth abundant elements. In this study temperature dependencies (T = 10-300 K) of current-voltage (J-V) characteristics and external quantum efficiency (EQE) spectra of CZTS monograin layer solar cells were measured in order to clarify current transport in CZTS that is still not fully understood. Three different temperature ranges can be distinguished from the temperature dependence of the series resistance (R{sub s}) obtained from J-V measurements and the effective bandgap energy (E{sub g}{sup ⁎}) determined from the EQE spectra. Thermally activated conductivity, Mott's variable-range hopping conductivity, and very low temperature (< 40 K) blocking of the interface recombination were observed. - Highlights: • Cu{sub 2}ZnSnS{sub 4} monograin layer solar cell temperature dependent parameters were studied. • Thermally activated conductivity at temperatures T > 90 K • Mott's variable-range hopping conductivity at temperatures T = 90-40 K • Very low temperature (< 40 K) blocking of interface recombination was observed.

  18. Performance Evaluation of a Solar Dryer with Finny, Perforated Absorber Plate Collector Equipped with an Air Temperature Control System for Dill Drying

    Directory of Open Access Journals (Sweden)

    M Razmipour

    2015-03-01

    Full Text Available Dill is one of the most important plants in the world because of its medicinal properties and it is widely used as a vegetable in the most parts of Iran. In the present study a new solar dryer with finny, perforated absorber plate collector was utilized to dry fresh dill. The dryer was comprised of a solar collector, a product container, a fan and a drying air temperature controller. The temperature controller was used as a control system to regulate the drying air temperature. Thermal performance of the dryer with finny, perforated solar collector was compared with that of a simple flat plate solar collector at different airflow rates. The effect of drying air temperature at three levels (45, 55 and 65 °C, the product size at three lengths (3, 5 and 7 cm and two different modes of drying (mixed and indirect on the dryer performance was investigated. The results showed that the finny, perforated absorber plate solar collector could improve the thermal efficiency about 11% in comparison with the flat plate collector and the highest thermal efficiency was achieved at the maximum airflow rate. Meanwhile, increasing the air temperature and decreasing the product size caused a significant reduction in energy consumption. Solar fraction reduced by increasing the air temperature. Finally a maximum dryer efficiency of 70% was observed at air temperature of 65 oC, product size of 3 cm with mixed mode drying.

  19. A Study of Solar Thermal Propulsion System Enhancement via Thermal Storage and Thermal-electric Conversion

    Science.gov (United States)

    2010-03-24

    material. Molybdenum has a thermal conductivity of 138 W/mK, while rheniums is much lower at 39.6 W/mK 2 . Zirconium Boride (ZrB2) and Hafnium Boride ...14,000 Iridium 77 2739 213 147 $42,000 Niobium 41 2750 323 53.7 $170 Molybdenum 42 2896 390 138 $100 The materials listed in Table 1 do not...this paper, several materials with melting points above 3000 K are boride compounds and several of those that are not borides contain elements which

  20. Drying of Rhinacanthus nasutus (Linn. Kurz. using a solar dryer incorporated with a backup thermal energy storage from wood combustion

    Directory of Open Access Journals (Sweden)

    Perapong Tekasakul

    2006-05-01

    Full Text Available An indirect, natural convection, solar cabinet dryer incorporated with a backup thermal energy storage from wood combustion was designed and tested with the Thai herb, Rhinacanthus nasutus (Linn. Kurz. Most of Thai herbs are widely used as traditional medicine and drying is an initial step in the production process. Solar dryer with a biomass backup heating system is the most feasible solution to drying in Thailand. In this work, a 4 m x 5 m solar collector was used to absorb solar radiation for heating the incoming air during the daytime, while a biomass burner was used to supply heat when solar energy was not possible. Heat from fuelwood combustion was accumulated in the thermal storage system made of bricks, and was used to heat up the incoming air. Results showed that the herb was dried uniformly and the temperature inside the drying cabinet could be maintained above 50ºC for more than 10 hours. Thermal efficiency when using solar energy was 10.5%, but the value was less than 1% when using the heat from biomass burning. This resulted from the low moisture content of the products after being dried by the solar energy. The dryer is beneficial to the operators, particularly in southern Thailand, where continuous drying is required. This dryer is by no means limited to drying of the herb. Currently, four dryers of the same model have been used by farmer groups in southern Thailand for drying bananas, several types of herbs, fish, and other products. In economic consideration, its payback period is 5.5 years when compared with the LPG-equipped dryer. When the total cost and production capacity are considered, its payback period is about 6 years.

  1. Modeling and performance simulation of 100 MW LFR based solar thermal power plant in Udaipur India

    Directory of Open Access Journals (Sweden)

    Deepak Bishoyi

    2017-12-01

    Full Text Available Solar energy is the most abundant source of energy on the earth and considered as an important alternative to fossil fuels. Solar energy can be converted into electric energy by using two different processes: photovoltaic conversion and the thermodynamic cycles. Lifetime and efficiency of PV power plant is lesser as compared to the CSP technology. CSP technology is viewed as one of the most promising alternative technology in the field of solar energy utilization. A 100 MW Linear Fresnel Reflector solar thermal power plant design with 6 hours of thermal energy storage has been evaluated for thermal performance using NREL SAM. A location receiving an annual DNI of 2248.17 kWh/m2/year in Rajasthan is chosen for the technical feasibility of hypothetical CSP plant. The plant design consists of 16 numbers of solar collector modules in a loop. HITEC solar salt is chosen as an HTF due to its excellent thermodynamic properties. The designed plant can generate annual electricity of 263,973,360 kWh with the plant efficiency of 18.3 %. The capacity utilization of the proposed LFR plant is found to be 30.2%. The LFR solar thermal power plant performance results encourage further innovation and development of CSP plants in India. Keywords: Linear Fresnel Reflector (LFR solar thermal power plant, SAM (System Advisor Model, India

  2. Benchmark Test of Differential Emission Measure Codes and Multi-thermal Energies in Solar Active Regions

    Science.gov (United States)

    Aschwanden, Markus J.; Boerner, Paul; Caspi, Amir; McTiernan, James M.; Ryan, Daniel; Warren, Harry

    2015-10-01

    We compare the ability of 11 differential emission measure (DEM) forward-fitting and inversion methods to constrain the properties of active regions and solar flares by simulating synthetic data using the instrumental response functions of the Solar Dynamics Observatory/ Atmospheric Imaging Assembly (SDO/AIA) and EUV Variability Experiment (SDO/EVE), the Reuven Ramaty High Energy Solar Spectroscopic Imager (RHESSI), and the Geostationary Operational Environmental Satellite/ X-ray Sensor (GOES/XRS). The codes include the single-Gaussian DEM, a bi-Gaussian DEM, a fixed-Gaussian DEM, a linear spline DEM, the spatial-synthesis DEM, the Monte-Carlo Markov Chain DEM, the regularized DEM inversion, the Hinode/ X-Ray Telescope (XRT) method, a polynomial spline DEM, an EVE+GOES, and an EVE+RHESSI method. Averaging the results from all 11 DEM methods, we find the following accuracies in the inversion of physical parameters: the EM-weighted temperature Tw^{fit}/Tw^{sim}=0.9±0.1, the peak emission measure EMp^{fit}/EMp^{sim}=0.6±0.2, the total emission measure EMt^{fit}/EMt^{sim}=0.8±0.3, and the multi-thermal energies E_{th}^{fit}/EM_{th}^{approx}=1.2±0.4. We find that the AIA spatial-synthesis, the EVE+GOES, and the EVE+RHESSI method yield the most accurate results.

  3. Active Wireless Temperature Sensors for Aerospace Thermal Protection Systems

    Science.gov (United States)

    Milos, Frank S.; Karunaratne, K.; Arnold, Jim (Technical Monitor)

    2002-01-01

    Health diagnostics is an area where major improvements have been identified for potential implementation into the design of new reusable launch vehicles in order to reduce life-cycle costs, to increase safety margins, and to improve mission reliability. NASA Ames is leading the effort to advance inspection and health management technologies for thermal protection systems. This paper summarizes a joint project between NASA Ames and Korteks to develop active wireless sensors that can be embedded in the thermal protection system to monitor sub-surface temperature histories. These devices are thermocouples integrated with radio-frequency identification circuitry to enable acquisition and non-contact communication of temperature data through aerospace thermal protection materials. Two generations of prototype sensors are discussed. The advanced prototype collects data from three type-k thermocouples attached to a 2.54-cm square integrated circuit.

  4. Temperature mapping, thermal diffusivity and subsoil heat flux at ...

    Indian Academy of Sciences (India)

    Thermal diffusivity () of the soil has been calculated by range and lag methods and also from amplitudes and phase angles of first and second harmonics. The two methods lead to similar results. Diurnal soil heat ux and soil temperatures at different depths are modelled and found to be comparable with observations.

  5. THERMAL COUPLE FOR MEASURING TEMPERATURE IN A REACTOR

    Science.gov (United States)

    Kanne, W.

    1959-11-24

    A thermocouple device for measuring the temperature of a flowing fluid in a conduit within which is positioned a metallic rod is presented. A thermocouple junction is secured to the rod centrally, and thermal insulating support disks having a diameter greater than the rod are secured to the end portions of the rod and adapted to fit transversely in the conduit.

  6. THE EFFECT OF THE THICKNESS OF A PACKED BED ON THE DYNAMIC AND THERMAL BEHAVIOR OF A SOLAR DRYER

    Directory of Open Access Journals (Sweden)

    S KHALDI

    2015-06-01

    Full Text Available Drying food in the sun is a safe, easy and economical way to preserve food, especially fruits. Cabinet dryers are the most popular equipment for fruit drying. Because of intermittent nature of solar energy, storage is required for uninterrupted supply in order to match the needs. The main objective of this study is to assess effectiveness of continuous solar dryer integrated with packed bed as thermal storage with natural airflow for drying figs (Ficuscarica. The cabinet dryer were envisaged theoretically (computational fluid dynamics (CFD. The distribution of the velocity and temperature of air within the solar dryer were presented during one day of August and under the climate conditions of Tlemcen (Algeria.  The effects of presence of a packed bed on the distribution of velocity and temperature of airflow and on the temperature of figs were analyzed. The results show that the solar dryer design, incorporating a packed bed enhances the capabilities and performance of the solar dryer, through increasing time of drying.

  7. Geographic market suitability analysis for low- and intermediate-temperature solar IPH systems

    Energy Technology Data Exchange (ETDEWEB)

    Turner, A.K.; Weber, J.C.; DeAngelis, M.

    1981-12-01

    Previous studies of the industrial market for solar energy systems have considered the level of solar radiation as the main determinant of geographic markets in the US. This study evaluates geographical markets extensively based on such criteria as output of different types of low- and intermediate-temperature solar thermal collectors, air quality constraints for competitive fuels, state solar tax incentives, fuel costs, low industrial use of coal, high industrial growth areas, and industry energy consumption in different parts of the US. Market suitability analysis and mapping techniques, refined in the past 20 years by land use planners, were used to evaluate geographical markets. A computer-aided system, Generalized Map Analysis Planning System (GMAPS), performed interactive, cellular, computer mapping, and composite mapping. Results indicate that the US Southwest and West are the most attractive geographical markets for solar IPH, based on an equal weighting of the evaluation criteria. The West North-Central and East South-Central regions appear to have the least attractive markets. Specific areas within states where solar IPH systems have distinct marketing advantages also are apparent from the composite maps. However, when different weights are assigned to the various criteria, the results change significantly for some regions of the country, such as the New England, Mid-Atlantic, and West South-Central 2 regions. The results of this work will become less valid in the future as state incentives for solar IPH, air quality regulations, and the status of competitive fuels all change. Volume I contains study results and maps.

  8. Thermocline thermal storage systems for concentrated solar power plants: One-dimensional numerical model and comparative analysis

    DEFF Research Database (Denmark)

    Modi, Anish; Pérez-Segarra, Carlos David

    2014-01-01

    Concentrated solar power plants have attracted increasing interest from researchers and governments all over the world in recent years. An important part of these plants is the storage system which improves dispatchability and makes the plant more reliable. In this paper, a one...... designing the power cycle for concentrated solar power applications. It was also observed that the cycle durations and the time required to attain cyclic conditions are highly sensitive to not only the storage temperature difference, but also the cut-off temperature difference. © 2013 Elsevier Ltd.......-dimensional transient mathematical model for a single-tank thermocline thermal energy storage system is presented. The model used temperature dependent correlations to obtain the thermophysical properties for the heat transfer fluid and considered heat loss through the tank wall. The effect of variation in important...

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2013-09-26

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

  10. Solar tests of aperture plate materials for solar thermal dish collectors

    Science.gov (United States)

    Jaffe, L. D.

    1984-01-01

    If a malfunction occurs in a solar thermal point-focus distributed receiver power plant while a concentrator is pointed at the sun, motion of the concentrator may stop. As the sun moves relative to the earth, the spot of concentrated sunlight then slowly walks off the receiver aperture, across the receiver face plate, and perhaps across adjacent portions of the concentrator. Intense local heating by the concentrated sunlight may damage or destroy these parts. The behavior of various materials under conditions simulating walk-off of a parabolic dish solar collector were evaluated. Each test consisted of exposure to concentrated sunlight at a peak flux density of about 7000 kW/square meter for 15 minutes. Types of materials tested included graphite, silicon carbide, silica, various silicates, alumina, zirconia, aluminum, copper, steel, and polytetrafluroethylene. The only material that neither cracked nor melted was grade G-90 graphite. Grade CS graphite, a lower cost commercial grade, cracked half-way across, but did not fail apart. Both of these grades are medium-grain extruded graphites. A graphite cloth (graphitized polyacrylonitrile) showed fair performance when tested as a single thin ply; it might be useful as a multi-ply assembly. High purity slipcast silica showed some promise also.

  11. Measurement of temperature-dependent viscosity and thermal conductivity of alumina and titania thermal oil nanofluids

    Science.gov (United States)

    Cieśliński, Janusz T.; Ronewicz, Katarzyna; Smoleń, Sławomir

    2015-12-01

    In this study the results of simultaneous measurements of dynamic viscosity, thermal conductivity, electrical conductivity and pH of two nanofluids, i.e., thermal oil/Al2O3 and thermal oil/TiO2 are presented. Thermal oil is selected as a base liquid because of possible application in ORC systems as an intermediate heating agent. Nanoparticles were tested at the concentration of 0.1%, 1%, and 5% by weight within temperature range from 20 °C to 60 °C. Measurement devices were carefully calibrated by comparison obtained results for pure base liquid (thermal oil) with manufacturer's data. The results obtained for tested nanofluids were compared with predictions made by use of existing models for liquid/solid particles mixtures.

  12. Measurement of temperature-dependent viscosity and thermal conductivity of alumina and titania thermal oil nanofluids

    Directory of Open Access Journals (Sweden)

    Cieśliński Janusz T.

    2015-12-01

    Full Text Available In this study the results of simultaneous measurements of dynamic viscosity, thermal conductivity, electrical conductivity and pH of two nanofluids, i.e., thermal oil/Al2O3 and thermal oil/TiO2 are presented. Thermal oil is selected as a base liquid because of possible application in ORC systems as an intermediate heating agent. Nanoparticles were tested at the concentration of 0.1%, 1%, and 5% by weight within temperature range from 20 °C to 60 °C. Measurement devices were carefully calibrated by comparison obtained results for pure base liquid (thermal oil with manufacturer’s data. The results obtained for tested nanofluids were compared with predictions made by use of existing models for liquid/solid particles mixtures.

  13. Performance study of a laboratory model shallow solar pond with and without single transparent glass cover for solar thermal energy conversion applications.

    Science.gov (United States)

    Ganesh, S; Arumugam, S

    2016-12-01

    The thermal performance of a shallow solar pond with and without the single transparent glass cover has been investigated experimentally. This experiment has been performed during the summer season of 2014 under the operational condition for five different storage volumes of water upto a maximum of 10liter. The pond performance is investigated in terms of the rate of energy collected and its collection efficiency. A Low Density Polyethylene (LDPE) black sheet liner of 200μm thickness was laid on all the interior sides of the pond for solar energy absorption. A clear transparent PVC plastic sheet of 150μm thickness was laid over the water surface as evaporation suppressing membrane. Calibrated Copper constantan thermocouples were used to measure the temperatures of the system. A highest temperature of 81.5°C has been achieved for the stored volume of 2liter of water, when the pond was used with a single transparent glass cover of 5mm thickness. When the shallow solar pond was used without the transparent glass cover the system attained a maximum temperature of 62°C for the same stored volume of 2liter. A comparison between the two conditions of with and without the transparent glass cover, on the thermal performance of the SSP has been reported. A shallow solar pond system of the present type could be used us a source of warm water, of desired temperature, below 10°C which are required for the domestic and industrial utilities. The global warming is increased day by day; inorder to reduce global warming a typical method of small scale shallow solar pond has been used to absorb the radiation from the sun to convert it to useful heat energy by the source of water. The SSP is an eco friendly way to generate energy without polluting our environment and in an environment safety manner. Based on environmental safety this study has experimentally investigated the thermal performance of the shallow solar pond. Copyright © 2016 Elsevier Inc. All rights reserved.

  14. Estimate of thermal fatigue lifetime for the INCONEL 625lCF plate while exposed to concentrated solar radiation

    Directory of Open Access Journals (Sweden)

    Rojas-Morín, A.

    2011-04-01

    Full Text Available A system for testing the thermal cycling of materials and components has been developed and installed at the DISTAL-I parabolic dish facility located at the Plataforma Solar de Almería (PSA in Spain. This system allows us to perform abrupt heating/cooling tests by exposing central solar receiver materials to concentrated solar radiation. These tests are performed to simulate both the normal and critical operational conditions of the central solar receiver. The thermal fatigue life for the INCONEL 625LCF® plate when subjected to concentrated solar radiation has been estimated with this system. We have also developed a numerical model that evaluates the thermal behavior of the plate material; additionally, the model yields the tensile-compressive stresses on the plate, which allow the estimation of the Stress-Life (S-N fatigue curves. These curves show that the lifetime of the plate is within the High Cycle Fatigue (HCF region at the operational temperatures of both 650 °C and 900 °C.

    En el concentrador solar de disco parabólico DISTAL-I, situado en la Plataforma Solar de Almería (PSA, en España, se ha instalado un sistema para pruebas de ciclado térmico de materiales. Este sistema permite realizar pruebas abruptas de calentamiento y enfriamiento, en materiales para receptores solares de torre central, al exponerlos a radiación solar concentrada. Estas pruebas se realizan para simular las condiciones de operación de un receptor solar, las condiciones críticas y las condiciones normales. Con este sistema se ha estimado el tiempo de vida bajo fatiga térmica, en una placa de INCONEL 626LCF®, cuando es sometida a radiación solar concentrada. Asimismo, hemos desarrollado un modelo numérico que evalúa el desarrollo térmico en el material de la placa: adicionalmente, el modelo obtiene los esfuerzos de tensión-compresión en la placa, los cuales permiten la estimaciónde las curvas de fatiga vidaesfuerzo (S-N. Estas curvas

  15. Process and Economic Optimisation of a Milk Processing Plant with Solar Thermal Energy

    DEFF Research Database (Denmark)

    Bühler, Fabian; Nguyen, Tuong-Van; Elmegaard, Brian

    2016-01-01

    . Based on the case study of a dairy factory, where first a heat integration is performed to optimise the system, a model for solar thermal process integration is developed. The detailed model is based on annual hourly global direct and diffuse solar radiation, from which the radiation on a defined...... surface is calculated. Based on hourly process stream data from the dairy factory, the optimal streams for solar thermal process integration are found, with an optimal thermal storagetank volume. The last step consists of an economic optimisation of the problem to determine the optimal size......This work investigates the integration of solar thermal systems for process energy use. A shift from fossil fuels to renewable energy could be beneficial both from environmental and economic perspectives, after the process itself has been optimised and efficiency measures have been implemented...

  16. Monitoring solar-thermal systems: An outline of methods and procedures

    Energy Technology Data Exchange (ETDEWEB)

    Rosenthal, A. [New Mexico State Univ., Las Cruces, NM (United States). Southwest Technology Development Inst.

    1994-04-01

    This manual discusses the technical issues associated with monitoring solar-thermal systems. It discusses some successful monitoring programs that have been implemented in the past. It gives the rationale for selecting a program of monitoring and gives guidelines for the design of new programs. In this report, solar thermal monitoring systems are classified into three levels. For each level, the report discusses the kinds of information obtained by monitoring, the effort needed to support the monitoring program, the hardware required, and the costs involved. Ultimately, all monitoring programs share one common requirement: the collection of accurate data that characterize some aspect or aspects of the system under study. This report addresses most of the issues involved with monitoring solar thermal systems. It does not address such topics as design fundamentals of thermal systems or the relative merits of the many different technologies employed for collection of solar energy.

  17. Temperature Distribution and Thermal Performance of an Aquifer Thermal Energy Storage System

    Science.gov (United States)

    Ganguly, Sayantan

    2017-04-01

    Energy conservation and storage has become very crucial to make use of excess energy during times of future demand. Excess thermal energy can be captured and stored in aquifers and this technique is termed as Aquifer Thermal Energy Storage (ATES). Storing seasonal thermal energy in water by injecting it into subsurface and extracting in time of demand is the principle of an ATES system. Using ATES systems leads to energy savings, reduces the dependency on fossil fuels and thus leads to reduction in greenhouse gas emission. This study numerically models an ATES system to store seasonal thermal energy and evaluates the performance of it. A 3D thermo-hydrogeological numerical model for a confined ATES system is presented in this study. The model includes heat transport processes of advection, conduction and heat loss to confining rock media. The model also takes into account regional groundwater flow in the aquifer, geothermal gradient and anisotropy in the aquifer. Results show that thermal injection into the aquifer results in the generation of a thermal-front which grows in size with time. Premature thermal-breakthrough causes thermal interference in the system when the thermal-front reaches the production well and consequences in the fall of system performance and hence should be avoided. This study models the transient temperature distribution in the aquifer for different flow and geological conditions. This may be effectively used in designing an efficient ATES project by ensuring safety from thermal-breakthrough while catering to the energy demand. Based on the model results a safe well spacing is proposed. The thermal energy discharged by the system is determined and strategy to avoid the premature thermal-breakthrough in critical cases is discussed. The present numerical model is applied to simulate an experimental field study which is found to approximate the field results quite well.

  18. Thermal performance evaluation of the Northrop model NSC-01-0732 concentrating solar collector array at outdoor conditions. [Marshall Space Flight Center solar house test facility

    Science.gov (United States)

    1979-01-01

    The thermal efficiency of the concentrating, tracking solar collector was tested after ten months of operation at the Marshall Space Flight Center solar house. The test procedures and results are presented.

  19. Thermal analysis of high temperature phase transformations of steel

    Directory of Open Access Journals (Sweden)

    K. Gryc

    2013-10-01

    Full Text Available The series of thermal analysis measurements of high temperature phase transformations of real grain oriented electrical steel grade under conditions of two analytical devices (Netzsch STA 449 F3 Jupiter; Setaram SETSYS 18TM were carried out. Two thermo analytical methods were used (DTA and Direct thermal analysis. The different weight of samples was used (200 mg, 23 g. The stability/reproducibility of results obtained by used methodologies was verified. The liquidus and solidus temperatures for close to equilibrium conditions and during cooling (20 °C/min; 80 °C/min were determined. It has been shown that the higher cooling rate lead to lower temperatures for start and end of solidification process of studied steel grade.

  20. Examining a solar climate link in diurnal temperature ranges

    CERN Document Server

    Laken, Benjamin A; Shahbaz, Tariq; Pallé, Enric; 10.1029/2012JD17683

    2012-01-01

    A recent study has suggested a link between the surface level diurnal temperature range (DTR) and variations in the cosmic ray (CR) flux. As the DTR is an effective proxy for cloud cover, this result supports the notion that widespread cloud changes may be induced by the CR flux. If confirmed, this would have significant implications for our understanding of natural climate forcings. Here, we perform a detailed investigation of the relationships between DTR and solar activity (total solar irradiance and the CR flux) from more than 60 years of NCEP/NCAR reanalysis data and observations from meteorological station data. We find no statistically significant evidence to suggest that the DTR is connected to either long-term solar periodicities (11 or 1.68 year) or short-term (daily-timescale) fluctuations in solar activity, and we attribute previous reports on the contrary to an incorrect estimation of the statistical significance of the data. If a CR-DTR relationship exists, based on the estimated noise in DTR co...