DOCSLIB.ORG

Performance of a Selective-Surface Trombe Wall in a Small Commercial

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Performance of a Selective-Surface Trombe Wall in a Small Commercial SERI/TP-721-1158 , UC CATEGORY: UC-59a,c PERFORMANCE OF A SELECTIVE­ SURFACE TROMBE WALL IN A SMALL COMMERCIAL BUILDING R . JUDKOFF SOLAR ENERGY RESEARCH INSTITUTE F. SOKOL INDEPENDENT DESIGN BOULDER, COLORADO MARCH 1981 To BE PRESENTED AT THE AS/ISES ANNUAL ~~EETI NG CIVIC CENTER, PHILADELPHIA, PENN. 26 -30 MAY 1981 PREPARED UNDER TASK No. 1147.00 Solar Energy Research Institute A Division of Midwest Research Institute 1617 Cole Boulevard Golden, Colorado 80401 Prepa red for the U.S. Department of Energy Contract No. EG-77-C-01-4042 Printed in the United States of America Available from: National Technical Information Service U.S. Department of Commerce 5285 Port Royal Road Springfi eld, VA 22161 Price: Microfiche $3.00 Printed Copy $4. 00 NOTICE This report was prepared as an account of work sponsored by the United States Govern­ ment. Neither the United States nor the United States Department of Energy, nor any of their employees, nor any of their contractors, subcontractors, or their employees, makes any warranty, express or implied, or assumes any legal liability or responsibility for the accuracy, completeness or usefulness of any information, apparatus, product or process disclosed, or represents that its use would not infringe privately owned rights. PERFORMANCE OF A SELEC11VE-SURFACE TROMBE WALL IN A SMALL COMMERCIAL BUILDING R. Judkoff Buildings Systems Development Branch Solar Energy Research Institute 1617 Cole Boulevard Golden, Colorado 80401 F. Sokol Independent Design Boulder, Colorado ABSTRACT The design and construction of a 10096 passive cial building. The building was constructed in solar building utilizing a clerestory and a trombe February 1980 and has now completed one heating wall is described. The use of three selectively and cooling season. absorptive and emissive coverings on the trornbe wall outer surface are investigated. One of the coverings and its laminating adhesive are tested 2. THE PROGRAM for degradation after a year of exposure under normal operating conditions. Ambient tempera­ The key requirements of the client were: ture, room air temperature, trombe wall interior and exterior surface temperatures, and solar • daylighting for the shop area, radiation are measured. • acoustic decoupling from outside to prevent disturbance of nearby residences by machinery noise, 1. INTRODUC110N • security for machinery and wood stocks, Movable insulation is an expensive and incon­ • stable temperatures for precise setting of furn­ venient technique for reducing night heat losses iture glue joints, and from direc t gain and trombe wall systems. Vol­ ume II of the DOE Passive Handbook (1) indicates • minimal auxiliary heating and cooling. that a selective foil applied to the exterior surface of a trombe wall or water wall equals or exceeds the performance of R-9 movable insulation. This 3. THE BUILDING represents an extremely cost-effective alternative to movable insulation. Figures I and 2 show the south elevation and a sectional perspective of the building, respectively. Shortly after Los Alamos National Laboratory obtained these results (1) in test-cell experim ents Although this building would have had enough on selective surfaces, F. Sokol requested design internal storage mass to support an extensive assistance for a small furniture-making factory in direct gain system, the requirements for stable Boulder, Colo. I agreed to assist under the temperatures, security, and acoustic decoupling condition that this novel concept be tested on his suggested the use of a trombe wall. The require­ building. He consented and we proceeded to de­ ment for daylighting as well as the building sign and build what to my knowledge is the first occupancy schedule suggested the addition of a field application of a selective surface on a clerestory above the trombe wall. The clerestory masonry trombe wall in a residential or commer- along with the ceiling shape is intended to diffuse the light evenly in the space so that supplementary lighting is rarely needed during the day. Addi­ tionally, the clerestory provides rapid early morn­ ing warm-up and utilizes to some extent the great amount of thermal storage mass available in the structural floor slab, block walls, and machinery. The site slopes somewhat to the south, facilitating a 3-ft earth berm on the north wall. The c~erestory allows a solar collection area ~f 100 ft . The trombe wall collection area is 130 ft . Heat loss through the clerestory is prevented at night by a 3-in.-thick panel of bead board insula­ Fig. I. South Elevation tion which is controlled by a timer and a l/lS-hp Dayton motor. Fig. 2. Sectional Perspective Figure 3 illustrates the different modes of opera­ Figure 4 shows a typical wall section, and Table 1 tion of the building. In summer the north doors lists the building materials and the thermal prop­ can be opened along with the vents low on the erties of typical sec tions. trombe wall and those high on the south wall. This facilitates a strong ventilative flow which is rein­ forced by any heating at the outer surface of the 4. TIlE SELECTIVE SURFACE trombe wall. The roof overhang provides total shading of the clerestory and about 50% shading of In choosing the selective surface, Microsorb paint, the trombe wall through the summer months. On Berry Products selective foil, and Maxorb selec­ summer nights the north doors are shut for secur­ tive foil were investigated. These products were ity reasons. However, vents in these doors allow tested in July 1979 for solar spectrum absorptivity natural flushing of the building mass with cool and long-wave emissivity at the Solar Energy night air. The movable insulation panel may be Research Institute Materials Laboratory. The left in the open position throughout the summer. results are presented in Table 2. In winter the trombe wall vents are sealed. The selective surface keeps the air-gap temperature relatively cool so that there is little to be gained The Mlcrosorb paint was not selective enough and by allowing thermocirculation of the wall. The was eliminated from further consideration. The clerestory provides morning warm-up and more two foils were equally selective; however, the than offsets any daytime heat losses from the Berry product had several advantages. It came in building. It is better, therefore, to store that wider strips and was thus easier to apply. It did energy, which would otherwise be transferred into not have an adhesive backing. This was crucial the building during the day via thermosyphoning, in since the adhesive backing on Max orb foil was in­ the trombe wall for night use. tended for the metallic surfaces of active solar collector panels; and Maxorb could not guarantee their adhesive over the long term when applied to a masonry substrateo Winter II n/';-"'" Operable Night Insulation on-\ri1Hfr=~::::::"~=~'...!======:!..!::==';;==';;;;:;::;::::­ Automatic Timer Bead Beare R-9 Night Position. Selective Surface Trombe Wall 8" Concrete Block Grout-Filled ~--'i:['I 4" Moss-Rock Double Glass Vent -1" Air Gap Structural Slab Fig.3. Modes of Operation Table 1. BUll..DING CHARACTERISTICS a"Concrete Block Location: Boulder, Colo. Latitude: 39.7 north 3" Bead Board Orientation: 120 east of s~uth Insulation --*"l'O'GI\.l Trombe wall area: 130 ~t R-12 Clerestory area: 1 ft 200 Expanded Floor area: 800 ft Metal Lath----o\!l!x'\61 Typical Floor Slab: U = 0.4/perimeter· ft Stucco----ji~~Si~~ In-In. structural slab Glue Joinl---+IioY~ Perimeter insulation: 36 in. x 3 in. Dow Styrofoam SM Tie Wire ----1<1 Typical Roof Section: R-38 Outside Inside 0.5-in. gypsum board 10-in. loose fill insulation Fig. 4. Typical Wall Section o.s-t-. exterior ply Tar paper Pro-panel metal roofing Trombe Wall 6. ONE-YEAR DEGRADATION TEST OF SELEC­ TIVE FOIL AND LAMINATING AGENT Double-glazed, lI8-in. standard glass Selective surface: Berry Products On 13 March 1981, several small samples of selec­ selec tive foil, black chrome on tive foil were removed from the trombe wall sur­ copper substrate face to be tested for solar spectrum absorptivity Laminating adhesive: Dow Corning 795 and infrared emissivity. The results of the tests silicone building sealant are shown in Table 3. s-In. concrete block, grout-filled 4-in. moss rock Other Features Table 3. Date of Test: March 13, 1981 Air-lock vestibule entry R-9 night insulation on single-glazed clerestory Solar Coating Spectrum Infrared Emissivity 5. SELECnON OF AN ADHESIVE Absorptivity The selection of an adhesive to affix the selective Berry Products 0.89 0.05 foil to the masonry trombe wall involved a rather selective foil lengthy investigation. Los Alamos Natio~al after 1 year of Laboratory used a neoprene-based construetion normal operating adhesive in their test-cell experiment with selec­ exposure tive foils; however, their investigation lasted only several weeks, leaving doubt as to the long-term Adhesive Delamination BUbbling performance of the neoprene in contact with copper and masonry. A number of constru~ti~n Dow Silicone #795 None None observable adhesive manufacturers and Berry Products indi­ building and joint in addition to cated that we were the first to attempt such an sealer after 1 that noted at application in a full-scale building intended for year of normal time 0 f installa­ long-term usage, and they gave no guarantees. r:ve operating exposure tion eliminated neoprene-based glues at the suggestion of several adhesive company technical representa­ tives (2). We finally selected the silicone-based building sealant #795 by Dow Corning. TABLE 2. Solar Infrared Selective Surface Coating Substrate Cost Spectrum Emissivity Absorptivity Microsorb paint, well agitated, Dry standard finish, hollow­ $32/gal 0.91 0.75 2 coats applied core concrete block Berry Products selective foil NA $1.35/ft2 0.87 0.08 Maxorb selective foil NA $1.35/ft2 0.88 0.09 The results indicate no measurable degradation exterior surface temperature is primarily a tune­ after a year of normal operating exposure.
Load more

Recommended publications
  • Comparison of Selective Transmitters for Solar Thermal Applications
    Comparison of Selective Transmitters for Solar Thermal Applications ROBERT A. TAYLOR,1,2,* YASITHA HEWAKURUPPU,1 DREW DEJARNETTE,3 TODD P. OTANICAR3 1School of Mechanical and Manufacturing Engineering—The University of New South Wales, Gate 14, Barker St., Sydney, Australia, 2052 2School of Photovoltaics and Renewable Energy Engineering—The University of New South Wales, Gate 14, Barker St., Sydney, Australia, 2052 3Department of Mechanical Engineering, The University of Tulsa, 800 S. Tucker Dr., Tulsa, USA, 74104 *Corresponding author: [email protected] Received 10 March 2016; revised 13 April, 2016; accepted XX Month XXXX; posted X Month XXXX; published XX Month XXXX OCIS codes: (310.6860) Thin films, optical properties, (310.7005) Transparent conductive coatings, (350.6050) Solar Energy. ABSTRACT 1. INTRODUCTION Solar thermal collectors are radiative heat exchangers. Their efficacy is dictated predominantly by their absorption of short- An ideal selective solar component perfectly absorbs (or wavelength solar radiation and, importantly, by their emission of transmits) short wavelength radiation - e.g. for wavelengths long-wavelength thermal radiation. In conventional collector cut-off – while perfectly reflecting long designs, the receiver is coated with a selectively absorbing wavelength radiation – e.g. for wavelengths cut-off. This cut- surface (Black Chrome, TiNOx, etc.) which serves both of these betweenoff wavelength 0 and depends λ on operating temperature and the solar aims. As the leading commercial absorber, TiNOx consists of concentration ratio. ‘Selectivity’ is made possible> λ by the fact several thin, vapor deposited layers (of metals and ceramics) on a that terrestrial solar energy does not have a true blackbody metal substrate.
    [Show full text]
  • Solar Flat Plate Collectors Steve Denner and Stan Price-Washington State University
    Extension Bulletin 0948 Solar Flat Plate Collectors Steve Denner and Stan Price-Washington State University The flat plate collector performs an important func­ temperatures can exceed 300 oF. Special care should tion in a solar space or water heating system. The flat be taken to prevent stagnation of collectors built with plate collector absorbs solar energy and converts it to wood. Repeated exposure of wood to high tempera­ heat. This heat can be transported from the collector tures can lower wood's combustion temperature, for immediate use or stored for later use. thus creating a potential fire hazard. There are many different types of solar flat plate col­ Glazing lectors available commercially. These solar collectors The metallic flat plate collector is covered by a can be generally grouped into two categories; metallic transparent or translucent glazing material. The glaz­ flat plate collectors and those made from non-metallic ing material transmits the solar radiation onto the col­ materials. Both metallic and non-metallic collectors lector plate and helps trap heat within the collector. have proven to be successful in both space heating In Western Washington, the use of a single layer of and domestic water heating applications. In either glazing is usually cost effective for solar water heating case, consumers should investigate manufacturers' systems. The added insulating value of a second layer warranties and expectations of product life. The well­ makes double glazed collectors more appropriate for constructed flat plate collector can offer effective per­ solar space heating systems. formance over a lifetime of 20 to 25 years. There is a relatively wide choice of glazing materials Metallic Flat Plate Collector Design for use with flat plate collectors.
    [Show full text]
  • Apptied Energy
    T a(?3l t-t 965L) 4tþ< 2o.åL a reprint from Apptied Energy an International Journal Edited by S. D. PROBERT Published by APPLIED SCIENCE PUBLISHERS LTD Ripple Road, Barking, Essex, England RADIATION COOLING OF BUILDINGS AT NIGHT D. Mrcue¡-l and K. L. Brccs Diuision of Building Research, commonweatth scientifc and Industial Research organization, Graham Road,,H ighett, Vic.-3190 (Australià) SUMMARY The cooling of small buildings at night by radiation loss to tlte sky has bee, in'uestigated by monitoring the thermil prr¡or^once of two ltuts: one roofed with galuanised steel decking pain'ted white, wn¡ih acts as a'black bod¡r tvauelengths greater than for 3 ¡tm; the other with aluminium decking ,to which aluminised,Tedlar, ; sheet had been glued, I the'Tedlar' acting as a selectirr- íur¡orr'oirorting änd radiating rnainly in the 8-13 band. I ¡tm I The hut v'ith the painred roof vç'as cooled I ryarginall¡, better tlnn that with the i' 'Tedlar' cot'ered_loof. usefut cooling powers of 2)wm-2 were acltiered at a roof I temperature of 5"c, ambient l0.oc, and the gross I coolíng power probably exceeded f 29 w m-2 - calcurations based on a simpre"simuration of the sky, ,o¿rotion an I ¡,ierd limit of 40wm-'fo, the cooling'power of tlrc surfaces,and I "ppll sttggest tltat an ideally selecti¿^'e I surface operating undir tlte best possible clear-sk1t conditions has i I little adt'antage oL'er a black body ràdiator -l of rhe surfaces is signifcantlv lower than "itrttiir-,'rrirr)ï,ure i the antbient'air temperature.
    [Show full text]
  • Study of Selective Surface of Solar Heat Receiver
    International Journal of Energy Engineering 2012, 2(4): 138-144 DOI: 10.5923/j.ijee.20120204.05 Study of Selective Surface of Solar Heat Receiver Fuad Mammadov Azerbaijan State Oil Academy, Azerbaijan Republic, AZ1010, Baku city, D.Aliyeva 227 Abstract For increasing of solar heating energy plants’ absorbing possibility and reducing heat loss selective nano-covered surface application has great practical importance. In the investigation Cu+Ni+SiO2+Ni+SiO2 and Cu+Ni+ZnS content selective nano-covered surface’ usage in solar energy plants was studied. This content having high effectiveness was painted on the surface of the specific solar receiver. In comparison with the other selective surfaces this selective nano-covered surface supplies to keep its optical properties stable till T>500 temperature. New type solar receiver with the developed selective nano-covered surface was tested in natural condition and at the lab. In the paper the most necessary heat-energy parameters of this solar receiver were defined. ℃ Keywords Solar energy, selective surface, solar receiver, absorption can’t completely interfere into the nano and micro sized 1. Introduction holes on the pipe. Finally surface of the nano sized holes stays beaming and is reflecting sun rays. Besides on the For obtaining high effectiveness in solar energy plants surface of the solar receiver made from the steel material in solar hear receiver was covered by the special selective layer such holes rust appears, that leads to the rapid destruction of on the surface. Such surfaces give opportunity to increase the selective cover[3]. maximal effectiveness of solar receiver in sun radiation exchange.
    [Show full text]
  • Reduction of Chromium (VI) When Solar Selective Black Chromium Is Deposited in the Presence of Organic Additive Branko N
    University of South Carolina Scholar Commons Faculty Publications Chemical Engineering, Department of 1992 Reduction of Chromium (VI) when Solar Selective Black Chromium is Deposited in the Presence of Organic Additive Branko N. Popov University of South Carolina - Columbia, [email protected] Ralph E. White University of South Carolina - Columbia, [email protected] D. Slavkov University Kiril and Metodij, Skopje, Yugoslavia Z. Koneska University Kiril and Metodij, Skopje, Yugoslavia Follow this and additional works at: https://scholarcommons.sc.edu/eche_facpub Part of the Chemical Engineering Commons Publication Info Journal of the Electrochemical Society, 1992, pages 91-98. © The Electrochemical Society, Inc. 1992. All rights reserved. Except as provided under U.S. copyright law, this work may not be reproduced, resold, distributed, or modified without the express permission of The Electrochemical Society (ECS). The ra chival version of this work was published in the Journal of the Electrochemical Society. http://www.electrochem.org/ DOI: 10.1149/1.2069206 http://dx.doi.org/10.1149/1.2069206 This Article is brought to you by the Chemical Engineering, Department of at Scholar Commons. It has been accepted for inclusion in Faculty Publications by an authorized administrator of Scholar Commons. For more information, please contact [email protected]. J. Electrochem. Soc., Vol. 139, No. 1, January 1992 The Electrochemical Society, Inc. 91 14. L. T. Romankiw, S. Krongelb, E.E. Castellani, A.T. stracts, Vol. 88-2, Chicago, IL, Oct. 9-14, 1988. Pfeiffer, B. J. Stoeber, and J. D. Olsen, IEEE Trans. 24. T. Kessler and R. C. Alkire, Plat. Surf.
    [Show full text]
  • Large Area Conformal Infrared Frequency Selective Surfaces
    University of Central Florida STARS Electronic Theses and Dissertations, 2004-2019 2014 Large Area Conformal Infrared Frequency Selective Surfaces Jeffrey D'Archangel University of Central Florida Part of the Electromagnetics and Photonics Commons, and the Optics Commons Find similar works at: https://stars.library.ucf.edu/etd University of Central Florida Libraries http://library.ucf.edu This Doctoral Dissertation (Open Access) is brought to you for free and open access by STARS. It has been accepted for inclusion in Electronic Theses and Dissertations, 2004-2019 by an authorized administrator of STARS. For more information, please contact [email protected]. STARS Citation D'Archangel, Jeffrey, "Large Area Conformal Infrared Frequency Selective Surfaces" (2014). Electronic Theses and Dissertations, 2004-2019. 4777. https://stars.library.ucf.edu/etd/4777 LARGE AREA, CONFORMAL INFRARED FREQUENCY SELECTIVE SURFACES by JEFFREY ALLEN D’ ARCHANGEL B.S. Saginaw Valley State University, 2009 M.S. University of Central Florida, 2011 A dissertation submitted in partial fulfillment of the requirement for the degree of Doctor of Philosophy in the College of Optics and Photonics: CREOL & FPCE at the University of Central Florida Orlando, Florida Fall Term 2014 Major Professor: Glenn D. Boreman © 2014 Jeffrey Allen D’ Archangel ii ABSTRACT Frequency selective surfaces (FSS) were originally developed for electromagnetic filtering applications at microwave frequencies. Electron-beam lithography has enabled the extension of FSS to infrared frequencies; however, these techniques create sample sizes that are seldom appropriate for real world applications due to the size and rigidity of the substrate. A new method of fabricating large area conformal infrared FSS is introduced, which involves releasing miniature FSS arrays from a substrate for implementation in a coating.
    [Show full text]
  • Chapter 7 Selective Solar Absorbers 1. Introduction
    CHAPTER 7 SELECTIVE SOLAR ABSORBERS Peter Bermel,1,¤ Jeongwon Lee,2 John D. Joannopoulos,2 Ivan Celanovic,2 & Marin Soljacie¸ˇ 2 1 Institute for Soldier Nanotechnologies, 77 Massachusetts Avenue, Cambridge, Massachusetts 02139 2 Birck Nanotechnology Center, Electrical & Computer Engineering, 1205 W. State St., West Lafayette, Indiana ¤Address all correspondence to Peter Bermel E-mail: [email protected] Efficiently capturing sunlight as heat is useful for a variety of applications, such as solar heating, solar thermal electricity generation, solar thermoelectrics, and solar thermophoto- voltaics. This process is most efficient when selective solar absorbers can be used to absorb most of the solar wavelengths found at the earth’s surface under standard atmospheric con- ditions, while suppressing infrared re-radiation induced by heating of the selective absorber. In practical terms, this generally corresponds to absorbing short wavelengths up to a cer- tain cutoff wavelength, and reflecting everything else. There are six classes of selective so- lar absorbers reviewed here: intrinsic absorbers, semiconductor–metal tandems, multilayer tandems, ceramic–metal composites (known as cermets), textured absorbers, and photonic crystals. It is found that the performance of cermets is the highest of the simple structures, while photonic crystals have the most room for improvement in the future, owing to unique capabilities in terms of selectivity with respect to wavelength, angle, and polarization. 1. INTRODUCTION Many technologies require the ability to extract heat from an appropriate source(s) and to direct it where it is needed, either for direct use or for conversion into electricity. One almost universally available heat source for terrestrial applications is sunlight.
    [Show full text]
  • To High-Temperature Solar Selective Absorber Materials CP02.2000 6
    July 2002 • NREL/TP-520-31267 Review of Mid- to High- Temperature Solar Selective Absorber Materials C.E. Kennedy National Renewable Energy Laboratory 1617 Cole Boulevard Golden, Colorado 80401-3393 NREL is a U.S. Department of Energy Laboratory Operated by Midwest Research Institute • Battelle • Bechtel Contract No. DE-AC36-99-GO10337 July 2002 • NREL/TP-520-31267 Review of Mid- to High- Temperature Solar Selective Absorber Materials C.E. Kennedy Prepared under Task No. CP02.2000 National Renewable Energy Laboratory 1617 Cole Boulevard Golden, Colorado 80401-3393 NREL is a U.S. Department of Energy Laboratory Operated by Midwest Research Institute • Battelle • Bechtel Contract No. DE-AC36-99-GO10337 NOTICE This report was prepared as an account of work sponsored by an agency of the United States government. Neither the United States government nor any agency thereof, nor any of their employees, makes any warranty, express or implied, or assumes any legal liability or responsibility for the accuracy, completeness, or usefulness of any information, apparatus, product, or process disclosed, or represents that its use would not infringe privately owned rights. Reference herein to any specific commercial product, process, or service by trade name, trademark, manufacturer, or otherwise does not necessarily constitute or imply its endorsement, recommendation, or favoring by the United States government or any agency thereof. The views and opinions of authors expressed herein do not necessarily state or reflect those of the United States government or any agency thereof. Available electronically at http://www.osti.gov/bridge Available for a processing fee to U.S. Department of Energy and its contractors, in paper, from: U.S.
    [Show full text]
  • International Journal of Energy and Environment
    INTERNATIONAL JOURNAL OF ENERGY AND ENVIRONMENT Volume 3, Issue 1, 2012 pp.99-108 Journal homepage: www.IJEE.IEEFoundation.org An investigation on the performance characteristics of solar flat plate collector with different selective surface coatings Madhukeshwara. N1, E. S. Prakash2 1 Department of Mechanical Engineering, B.I.E.T, Davanagere, Karnataka, India. 2 Department of Studies in Mechanical Engineering, U.B.D.T.C.E, Davanagere, Karnataka, India. Abstract In the present work, investigations are made to study performance characteristics of solar flat plate collector with different selective surface coatings. Flat plate collector is one of the important solar energy trapping device which uses air or water as working fluid. Of the many solar collector concepts presently being developed, the relative simple flat plate solar collector has found the widest application so far. Its characteristics are known, and compared with other collector types, it is the easiest and least expensive to fabricate, install, and maintain. Moreover, it is capable of using both the diffuse and the direct beam solar radiation. For residential and commercial use, flat plate collectors can produce heat at sufficiently high temperatures to heat swimming pools, domestic hot water, and buildings; they also can operate a cooling unit, particularly if the incident sunlight is increased by the use of reflector. Temperatures upto 70 oC are easily attained by flat plate collectors. With very careful engineering using special surfaces, reflectors to increase the incident radiation and heat resistant materials, higher operating temperatures are feasible. Copyright © 2012 International Energy and Environment Foundation - All rights reserved. Keywords: Selective surface coatings; Solar flat plate collector; Collector performance.
    [Show full text]
  • Cryogenic Selective Surfaces
    Cryogenic Selective Surfaces Final Report on a Phase I NIAC Study February 2016 Robert C. Youngquist and Mark A. Nurge Cryogenic Selective Surfaces NIAC Phase I Study February 2016 Final Report Preface Several years ago, a small piece of Space Shuttle Orbiter payload bay door liner was handed out to each member of the KSC workforce as a space memento. I remember studying this small piece of clear plastic with its reflective coating and wanting to understand why this was special. After some research, I soon understood that it was designed to reflect away sunlight, but still allow infrared energy to be emitted, allowing the payload bay doors of the Orbiter to radiate heat even in the presence of the Sun. I thought this was quite ingenious. Then, a few years later, I was working on galactic cosmic radiation (GCR) active shielding methods. I looked seriously at electrostatic shielding and could not find a workable path, so I considered magnetic field shielding. Many closed toroid designs had been proposed for this purpose, but their containment structures would generate significant radiation when they interact with the GCR, bypassing the protection of the magnetic field. So I began to look at open magnetic field structures composed of long lengths (kilometers) of superconducting wire located significant distances from the spacecraft. I became convinced that this was the only practical route for protecting astronauts from GCR with an active shield, but the key problem was how to keep these wires cold so that they would stay superconducting. Prior work had assumed that the wires could be located in liquid-nitrogen sheaths, but I doubted that was practical or would even be possible.
    [Show full text]
  • Harnessing Heat Beyond 200 °C from Unconcentrated Sunlight with Nonevacuated Transparent Aerogels † ‡ Lin Zhao, Bikram Bhatia, Sungwoo Yang, Elise Strobach, Lee A
    Article Cite This: ACS Nano XXXX, XXX, XXX−XXX www.acsnano.org Harnessing Heat Beyond 200 °C from Unconcentrated Sunlight with Nonevacuated Transparent Aerogels † ‡ Lin Zhao, Bikram Bhatia, Sungwoo Yang, Elise Strobach, Lee A. Weinstein, Thomas A. Cooper, Gang Chen,* and Evelyn N. Wang* Department of Mechanical Engineering, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, Massachusetts 02139, United States *S Supporting Information ABSTRACT: Heat at intermediate temperatures (120−220 °C) is in significant demand in both industrial and domestic sectors for applications such as water and space heating, steam generation, sterilization, and other industrial processes. Harnessing heat from solar energy at these temperatures, however, requires costly optical and mechanical components to concentrate the dilute solar flux and suppress heat losses. Thus, achieving high temperatures under unconcentrated sunlight remains a technological challenge as well as an opportunity for utilizing solar thermal energy. In this work, we demonstrate a solar receiver capable of reaching over 265 °C under ambient conditions without optical concentration. The high temper- atures are achieved by leveraging an artificial greenhouse effect within an optimized monolithic silica aerogel to reduce heat losses while maintaining high solar transparency. This study demonstrates a viable path to promote cost-effective solar thermal energy at intermediate temperatures. KEYWORDS: solar thermal conversion, transparent aerogel, artificial greenhouse effect, light scattering, radiative transfer he greenhouse effect in the Earth’s atmosphere provides effect, this aerogel transmits sunlight but traps heat by blocking the warmth essential for the survival of our ecosystem. thermal emission. The receiver requires no selective surface or Unfortunately, increasing human activities such as vacuum enclosure and can operate at ambient conditions.
    [Show full text]
  • Characterization of Selective Solar Absorbers
    Comprehensive Summaries of Uppsala Dissertations from the Faculty of Science and Technology 556 _____________________________ _____________________________ Characterization of Selective Solar Absorbers Experimental and Theoretical Modeling BY TUQUABO TESFAMICHAEL ACTA UNIVERSITATIS UPSALIENSIS UPPSALA 2000 Dissertation for the Degree of Doctor of Philosophy in Solid State Physics presented at Uppsala University in 2000 Abstract Tesfamichael, T. 2000. Characterization of Selective Solar Absorbers. Experimental and Theoretical Modeling. Acta Universitatis Upsaliensis. Comprehensive Summaries of Uppsala Dissertation from the Faculty of Science and Technology 556.79 pp. Uppasla. ISBN 91-554-4772-4. This thesis deals with the preparation, optical characterization and analyses of experimental work and theoretical modeling on selective solar absorbers used in solar thermal collectors. The overall goal has been to obtain efficient absorbers by optimizing the optical properties, and to improve their durability using cost-effective techniques. A Ni-Al2O3 absorber was pyrolytically coated with SnO2 to improve its coating quality. Undesirable increase of solar reflectance obtained as a result of the SnO2 was reduced by applying a silica antireflection layer produced by a dipping technique from colloidal silica sol. Annealing of Ni particles in an Al2O3 matrix was also carried out and compared to particles heated without the matrix. Due to the Al2O3 matrix, a much slower oxidation rate was found for the embedded particles. In addition, the optical performance of commercial Ni-Al2O3 and Ni-NiOx absorbers were experimentally compared at oblique incidence. A better solar-absorptance of the Ni-Al2O3 at higher angles of incidence was found. This is due to enhanced optical interference in the double-layer structure of Ni-Al2O3, which could not be achieved in the graded index film of Ni-NiOx.
    [Show full text]