John B. Rekstad

• Steffen, Ronald; Meir, Michaela Georgine; Rekstad, John Bernhard & Röder, Beate (2018). Kinetics of degradation-induced polymer luminescence: A polyphenylene sulfide/elastomer blend under dry heat exposure. Polymer. ISSN 0032-3861. 136, s. 71–83. doi: 10.1016/j.polymer.2017.12.045. Fulltekst i vitenarkiv
• Steffen, Robert; Wallner, Gernot; Rekstad, John Bernhard & Röder, Beate (2016). General characteristics of photoluminescence from dry heat aged polymeric materials. Polymer degradation and stability. ISSN 0141-3910. 134, s. 49–59. doi: 10.1016/j.polymdegradstab.2016.09.032. Fulltekst i vitenarkiv
• Carlsson, Bo; Meir, Michaela Georgine; Rekstad, John Bernhard; Preiss, Dieter & Thomas, Ramschak (2016). Replacing traditional materials with polymeric materials in solar thermosiphon systems – Case study on pros and cons based on a total cost accounting approach. Solar Energy. ISSN 0038-092X. 125, s. 294–306. doi: 10.1016/j.solener.2015.12.005. Fulltekst i vitenarkiv Vis sammendrag

  The pros and cons of replacing traditional materials with polymeric materials in solar thermosiphon systems were analysed by adopting a total cost accounting approach. In terms of climatic and environmental performance, polymeric materials reveal better key figures than traditional ones like metals. In terms of present value total cost of energy, taking into account functional capability, end user investment cost, O&M cost, reliability and climatic cost, the results suggest that this may also be true when comparing a polymeric based thermosiphon system with a high efficient thermosiphon system of conventional materials for DHW production in the southern Europe regions. When present values for total energy cost are assessed for the total DHW systems including both the solar heating system and the auxiliary electric heating system, the difference in energy cost between the polymeric and the traditional systems is markedly reduced. The main reason for the difference in results can be related to the difference in thermal performance between the two systems. It can be concluded that the choice of auxiliary heating source is of utmost importance for the economical competiveness of systems and that electric heating may not be the best choice.

• Rekstad, John Bernhard; Meir, Michaela Georgine; Murtnes, Espen & Dursun, Aylin Maria (2015). A comparison of the energy consumption in two passive houses, one with a solar heating system and one with an air-water heat pump. Energy and Buildings. ISSN 0378-7788. 96, s. 149–161. doi: 10.1016/j.enbuild.2015.02.059. Fulltekst i vitenarkiv
• Meir, Michaela Georgine; Murtnes, Espen; Dursun, Aylin Maria & Rekstad, John Bernhard (2014). Polymeric collectors or Heat Pump? Lessons learned from passive houses in Oslo. Energy Procedia. 48C, s. 914–923. doi: 10.1016/j.egypro.2014.02.105. Fulltekst i vitenarkiv
• Carlsson, Bo; Persson, Helena; Meir, Michaela Georgine & Rekstad, John Bernhard (2014). A total cost perspective on use of polymeric materials in solar collectors – Importance of environmental performance on suitability. Applied Energy. ISSN 0306-2619. 125, s. 10–20. doi: 10.1016/j.apenergy.2014.03.027. Fulltekst i vitenarkiv
• Larsen, Ann-Cecilie; Goriely, Stephane; Algin, Emel; Agvaanluvsan, Undraa; Bürger, Annetta & Görgen, Andreas [Vis alle 22 forfattere av denne artikkelen] (2011). Gamma-ray strength functions and their relation to astrophysics. AIP Conference Proceedings. ISSN 0094-243X. 1377, s. 239–246. doi: 10.1063/1.3628386. Fulltekst i vitenarkiv
• Seljom, Pernille Merethe; Rosenberg, Eva; Fidje, Audun; Haugen, Jan Erik; Meir, Michaela Georgine & Rekstad, John Bernhard [Vis alle 7 forfattere av denne artikkelen] (2011). Modelling the effects of climate change on the energy system—A case study of Norway. Energy Policy. ISSN 0301-4215. 39(11), s. 7310–7321. doi: 10.1016/j.enpol.2011.08.054. Fulltekst i vitenarkiv
• Larsen, Ann-Cecilie; Guttormsen, Magne Sveen; Krticka, Milan; Betak, Emil; Bürger, Alexander & Görgen, Andreas [Vis alle 14 forfattere av denne artikkelen] (2011). Analysis of possible systematic errors in the Oslo method. Physical Review C. Nuclear Physics. ISSN 0556-2813. 83. doi: 10.1103/PhysRevC.83.034315. Fulltekst i vitenarkiv
• Kahlen, Susanne; Wallner, Gernot; Lang, R.W.; Meir, Michaela Georgine & Rekstad, John Bernhard (2010). Aging behavior of polymeric solar absorber materials: Aging on the component level. Solar Energy. ISSN 0038-092X. 84(3), s. 459–465. doi: 10.1016/j.solener.2010.01.003. Fulltekst i vitenarkiv
• Olivares, A; Rekstad, John Bernhard; Meir, Michaela Georgine; Kahlen, Susanne & Wallner, Gernot (2010). Degradation model for an extruded polymeric solar thermal absorber. Solar Energy Materials and Solar Cells. ISSN 0927-0248. 94(6), s. 1031–1037. doi: 10.1016/j.solmat.2010.02.001. Fulltekst i vitenarkiv
• Siem, Sunniva; Agvaanluvsan, Undraa; Bürger, Alexander; Guttormsen, Magne Sveen; Larsen, Ann-Cecilie & Nyhus, Hilde-Therese [Vis alle 11 forfattere av denne artikkelen] (2009). Level densities and radiative strength functions. AIP Conference Proceedings. ISSN 0094-243X. 1090, s. 66–73. doi: 10.1063/1.3087125. Fulltekst i vitenarkiv
• Syed, Naeem Ul Hasan; Guttormsen, Magne Sveen; Ingebretsen, Finn; Larsen, Ann-Cecilie; Lonnroth, T & Rekstad, John Bernhard [Vis alle 9 forfattere av denne artikkelen] (2009). Level density and gamma-decay properties of closed shell Pb nuclei. Physical Review C. Nuclear Physics. ISSN 0556-2813. 79(2). doi: 10.1103/PhysRevC.79.024316. Fulltekst i vitenarkiv
• Siem, Sunniva; Guttormsen, Magne Sveen; Chankova, Rositsa; Larsen, Ann-Cecilie; Rekstad, John Bernhard & Syed, Naeem Ul Hasan [Vis alle 12 forfattere av denne artikkelen] (2008). Experimental Level densities and gamma-strength functions in rare earth nuclei. AIP Conference Proceedings. ISSN 0094-243X. 1005. Fulltekst i vitenarkiv
• Olivares, Lopez Andres F; Rekstad, John Bernhard; Meir, Michaela Georgine; Kahlen, Susanne & Wallner, Gernot (2008). A test procedure for extruded polymeric solar thermal absorbers. Solar Energy Materials and Solar Cells. ISSN 0927-0248. 92(4), s. 445–452. doi: 10.1016/j.solmat.2007.10.006. Fulltekst i vitenarkiv Vis sammendrag

  Abstract - An indentation test is proposed to study the degradation of extruded polymeric solar absorbers. The thermal degradation caused by accelerated aging is investigated. The results are compared with the thermal and mechanical impacts during the operation of the solar collector.

• Guttormsen, Magne Sveen; Larsen, Ann-Cecilie; Rekstad, John Bernhard; Schiller, Andreas; Siem, Sunniva & Syed, Naeem Ul Hasan [Vis alle 7 forfattere av denne artikkelen] (2008). Thermodynamic properties of atomic nuclei with T<1 MeV. AIP Conference Proceedings. ISSN 0094-243X. 1012, s. 198–202. Fulltekst i vitenarkiv
• Larsen, Ann-Cecilie; Guttormsen, Magne Sveen; Chankova, Rositsa; Ingebretsen, Finn; Lönnroth, Tom & Rekstad, John Bernhard [Vis alle 11 forfattere av denne artikkelen] (2008). Experimental nuclear level densities and gamma-ray strength functions in Sc and V isotopes. AIP Conference Proceedings. ISSN 0094-243X. 1005, s. 70–73. Fulltekst i vitenarkiv
• Larsen, Ann-Cecilie; Guttormsen, Magne Sveen; Chankova, Rositsa; Ingebretsen, Finn; Lönnroth, Tom & Rekstad, John Bernhard [Vis alle 11 forfattere av denne artikkelen] (2008). Puzzling gamma-ray strength functions in 44,45Sc and 50,51V. AIP Conference Proceedings. ISSN 0094-243X. s. 380–382. Fulltekst i vitenarkiv
• Siem, Sunniva; Guttormsen, Magne Sveen; Chankova, Rositsa; Larsen, Ann-Cecilie; Nyhus, Hilde-Therese & Rekstad, John Bernhard [Vis alle 10 forfattere av denne artikkelen] (2008). Level densities and gamma-strength functions in Sm isotopes. AIP Conference Proceedings. ISSN 0094-243X. s. 425–427. Fulltekst i vitenarkiv
• Algin, Emel; Agvaanluvsan, Undraa; Guttormsen, Magne Sveen; Larsen, Ann-Cecilie; Mitchell, Gary & Rekstad, John Bernhard [Vis alle 9 forfattere av denne artikkelen] (2008). Thermodynamic properties of 56,57Fe. Physical Review C. Nuclear Physics. ISSN 0556-2813. C78(054321). Fulltekst i vitenarkiv
• Larsen, Ann-Cecilie; Guttormsen, Magne Sveen; Chankova, Rositsa; Ingebretsen, Finn; Lönnroth, Tom & Messelt, Svein [Vis alle 11 forfattere av denne artikkelen] (2007). Nuclear level densities and gamma-ray strength functions in Sc-44,Sc-45. Physical Review C. Nuclear Physics. ISSN 0556-2813. doi: 10.1103/PhysRevC.76.044303. Fulltekst i vitenarkiv
• Siem, Sunniva; Guttormsen, Magne; Chankova, Rosita; Larsen, Ann-Cecilie; Rekstad, John Bernhard & Schiller, Andreas [Vis alle 7 forfattere av denne artikkelen] (2007). Level densities and gamma strength functions in Sm-146,Sm-147 nuclei. Acta Physica Polonica B. ISSN 0587-4254. 38(4), s. 1499–1502. Fulltekst i vitenarkiv
• Algin, E; Schiller, A; Voinov, A; Agvaanluvsan, U; Belgya, T & Bernstein, LA [Vis alle 19 forfattere av denne artikkelen] (2007). Bulk properties of iron isotopes. Physics of Atomic Nuclei. ISSN 1063-7788. 70, s. 1634–1639. doi: 10.1134/S1063778807090232. Fulltekst i vitenarkiv
• Guttormsen, Magne; Chankova, Rosita; Larsen, Ann-Cecilie; Rekstad, John Bernhard; Siem, Sunniva & Syed, Naeem Ul Hasan [Vis alle 9 forfattere av denne artikkelen] (2007). The role of broken cooper pairs in warm nuclei. Acta Physica Polonica B. ISSN 0587-4254. 38(4), s. 1489–1493. Fulltekst i vitenarkiv
• Larsen, Ann-Cecilie; Guttormsen, Magne; Chankova, Rosita; Ingebretsen, Finn; Lönnroth, Tom & Messelt, Svein [Vis alle 12 forfattere av denne artikkelen] (2007). Radiative strength functions of warm nuclei in the 1f(7/2) shell. Acta Physica Polonica B. ISSN 0587-4254. 38(4), s. 1495–1498. Fulltekst i vitenarkiv
• Guttormsen, Magne; Agvaanluvsan, Undraa; Chankova, Rositsa; Hjorth-Jensen, Morten; Rekstad, John Bernhard & Schiller, Andreas [Vis alle 10 forfattere av denne artikkelen] (2006). Single particle entropy in heated nuclei. AIP Conference Proceedings. ISSN 0094-243X. 831, s. 162–166. Fulltekst i vitenarkiv
• Larsen, Ann-Cecilie; Guttormsen, Magne; Chankova, Rositsa; Ingebretsen, Finn; Lønnroth, Tom & Messelt, Svein [Vis alle 12 forfattere av denne artikkelen] (2006). Heating nuclei in the mass region of A = 40-50. AIP Conference Proceedings. ISSN 0094-243X. 831, s. 544–547. Fulltekst i vitenarkiv
• Syed, Naeem Ul Hasan; Guttormsen, Magne; Siem, Sunniva; Ingebretsen, Finn; Lønnroth, Tom & Rekstad, John Bernhard [Vis alle 10 forfattere av denne artikkelen] (2006). Extracting experimental level densities in A=207-208 Nuclei. AIP Conference Proceedings. ISSN 0094-243X. 831, s. 548–550. Fulltekst i vitenarkiv
• Larsen, Ann-Cecilie; Chankova, Rositsa; Guttormsen, Magne; Ingebretsen, Finn; Messelt, Svein & Rekstad, John Bernhard [Vis alle 12 forfattere av denne artikkelen] (2006). Microcanonical entropies and radiative strength functions of 50,51V. Physical Review C. Nuclear Physics. ISSN 0556-2813. 73. doi: 10.1103/PhysRevC.73.064301. Fulltekst i vitenarkiv
• Chankova, Rositsa; Schiller, A; Agvaanluvsan, U; Algin, E; Bernstein, LA & Guttormsen, Magne [Vis alle 15 forfattere av denne artikkelen] (2006). Level densities and thermodynamical quantities of heated Mo93-98 isotopes. Physical Review C. Nuclear Physics. ISSN 0556-2813. 73. Fulltekst i vitenarkiv
• Guttormsen, Magne; Agvaanluvsan, Undraa; Chankova, Rositsa; Larsen, Ann-Cecilie; Rekstad, John Bernhard & Schiller, Andreas [Vis alle 9 forfattere av denne artikkelen] (2006). Experimental nuclear level densities and interpretation within the microcanonical ensemble. Proceedings of Science (PoS). Fulltekst i vitenarkiv Vis sammendrag

  Statistical properties of atomic nuclei are studied as function of the number of neutrons. The experimental method is based on particle-g coincidences measured in light-ion reactions with one charged ejectile. From particle-g coincidences, level densities and radiative strength functions can be simultaneously extracted from one and the same data set. Mid-shell nuclei show significant odd-even entropy differences interpreted as the single-particle entropy of the valence nucleon. However, these properties change when approaching closed shells. A model within the framework of the microcanonical ensemble is presented and compared with data from the molybdenum isotopes. The odd-even entropy difference disappears in the vicinity of the N =50 shell, and an overshoot of positive parity states is predicted.

• Schiller, A; Voinov, AV; Algin, E; Bernstein, LA; Garrett, PE & Guttormsen, Magne [Vis alle 9 forfattere av denne artikkelen] (2006). Primary versus secondary gamma intensities in Yb-171(n(th), gamma). Physical Review C. Nuclear Physics. ISSN 0556-2813. 74. Fulltekst i vitenarkiv

Se alle arbeider i NVA

• Rekstad, John Bernhard; Ingvild, Skjelland; Meersman, Els De; Yves, Klinger & Meir, Michaela Georgine (2016). Auf dem Sonnendach - Modifizierte Hochleistungskunststoffe zur Extrusion von Solarthermie Anwendungen. Kunststoffe. ISSN 0023-5563. 2, s. 77–79. Fulltekst i vitenarkiv Vis sammendrag

  Sonnenkollektoren können Solarenergie in thermische Energie für Heizungen und Warmwasseraufbereitung umwandeln. Der Solarabsorber muss dabei hohen thermischen und mechanischen Belastungen standhalten. Wurden für diese Anwendung bisher hauptsächlich Metalle eingesetzt, hat ein Forschungskonsortium nun spezielle Polymerblends dafür entwickelt. Im Vordergrund stand die effektive Extrusion eines Hochleistungskunststoffs zu großflächigen Doppelstegplatten.

• Meir, Michaela Georgine; Carlsson, Bo & Rekstad, John Bernhard (2013). Life-cycle assessment of polymeric thermosiphon collectors. Fulltekst i vitenarkiv
• Meir, Michaela Georgine; Rekstad, John Bernhard; Dursun, Aylin Maria & Murtnes, Espen (2013). Polymeric solar collectors or heat pump? - Lessons learned from passive houses in Oslo. Fulltekst i vitenarkiv
• Larsen, Ann-Cecilie; Bürger, Alexander; Eriksen, Tomas Kvalheim; Görgen, Andreas; Guttormsen, Magne Sveen & Hagen, Trine Wiborg [Vis alle 29 forfattere av denne artikkelen] (2011). Experiments of reaction model inputs: level density and gamma strength. Fulltekst i vitenarkiv
• Larsen, Ann-Cecilie; Guttormsen, Magne Sveen; Bürger, Alexander; Eriksen, Tomas Kvalheim; Görgen, Andreas & Hagen, Trine Wiborg [Vis alle 16 forfattere av denne artikkelen] (2011). Level density and gamma strength - achievements and challenges. Fulltekst i vitenarkiv
• Rekstad, John Bernhard (2010). New solar collectors in polymer materials. Fulltekst i vitenarkiv
• Rekstad, John Bernhard (2010). Polymeric solar collectors. [Internet]. SolarThermal World. Fulltekst i vitenarkiv
• Rekstad, John Bernhard (2010). Progress report, solar thermal collectors. Fulltekst i vitenarkiv
• Rekstad, John Bernhard (2010). Solar collector, recent development. Fulltekst i vitenarkiv
• Rekstad, John Bernhard (2010). Solar energy R&D in Norway. [Internet]. SolarThermal World. Fulltekst i vitenarkiv
• Rekstad, John Bernhard (2010). Solar Collector Absorbers in High-performance Polymer Materials. Fulltekst i vitenarkiv
• Berset, Simone Prytz & Rekstad, John Bernhard (2009). Uutnyttet potensial - Individuell måling av fjernvarme har et stort enøk-potensial. [Journal]. Magazin: Norsk VVS. Fulltekst i vitenarkiv
• Rekstad, John Bernhard & Borgestrand, Odd (2009). Fornybar energi. [Journal]. VVS aktuelt. Fulltekst i vitenarkiv
• Rekstad, John Bernhard & Nylund, Hilde Kari (2009). Polymerer er framtida. [Journal]. Magazin: Norsk VVS. Fulltekst i vitenarkiv
• Rekstad, John Bernhard & Kongsnes, Ellen (2009). Norge har jumboplass på solenergi. [Journal]. Stavanger Aftenbladet. Fulltekst i vitenarkiv
• Rekstad, John Bernhard (2009). Solenergi. Fulltekst i vitenarkiv
• Rekstad, John Bernhard (2009). Solenergi - den største potensielle energikilden. Fulltekst i vitenarkiv
• Rekstad, John Bernhard (2009). Energibruk i bygg. Hva kan sola bidra med? Fulltekst i vitenarkiv
• Rekstad, John Bernhard (2009). Polymer Materials for Solar Thermal Applications. Fulltekst i vitenarkiv
• Rekstad, John Bernhard (2009). ESFRI Energy WR, Roadmap for large research infrastructures in Europe. Fulltekst i vitenarkiv
• Rekstad, John Bernhard (2009). Om solenergi. Fulltekst i vitenarkiv
• Rekstad, John Bernhard (2009). Solenergi - en kilde i våre hender. Fulltekst i vitenarkiv
• Rekstad, John Bernhard (2009). Solar collectors in polymer materials. Fulltekst i vitenarkiv
• Rekstad, John Bernhard (2009). Solar thermal R&D at UiO. Fulltekst i vitenarkiv
• Rekstad, John Bernhard (2009). Solar thermal R&D at the University of Oslo. Fulltekst i vitenarkiv
• Rekstad, John Bernhard (2009). Solar heat - of interest in Norway? Fulltekst i vitenarkiv Vis sammendrag

  Norway has for a long time lagged behind on the statistics of utilization of solar heat. But in August 2008 the Norwegian institution Enova opened a programme for subsidizing solar heating systems. This made way to an increased interest on solar heat systems in Norway, as has earlier been seen in many other countries Rekstad will in this lecture discuss how solar heat utilization in buildings compares to alternative heating systems. Different technical solutions are available, and some research on solar heat is being done on the University of Oslo.

• Rekstad, John Bernhard (2009). Update of research: University of Oslo and Aventa. Fulltekst i vitenarkiv
• Rekstad, John Bernhard (2008). Om solenergi. Fulltekst i vitenarkiv
• Rekstad, John Bernhard (2008). Solar Energy. Fulltekst i vitenarkiv
• Rekstad, John Bernhard (2008). Finnes løsningen på energiutfordringene i kjernefysikken ? Fulltekst i vitenarkiv
• Rekstad, John Bernhard (2008). Utnyttelse av varmestråling - varme og kulde fra solstråling. Fulltekst i vitenarkiv
• Rekstad, John Bernhard (2008). Utarbeidelse av ny "ESFRI Roadmap for Large Reserach Infrastructures" i Europa. Fulltekst i vitenarkiv
• Rekstad, John Bernhard (2008). Progress report, solar energy research. Fulltekst i vitenarkiv
• Rekstad, John Bernhard (2008). Termisk solenergi i større bygninger. Fulltekst i vitenarkiv
• Rekstad, John Bernhard (2008). Sola som energigiver. Praktisk utnyttelse av solenergi. Fulltekst i vitenarkiv
• Rekstad, John Bernhard (2008). Fornybare energikilder - tema solenergi. Fulltekst i vitenarkiv
• Rekstad, John Bernhard (2008). Forskning og utvikling innen termisk solenergi. Fulltekst i vitenarkiv
• Rekstad, John Bernhard (2008). Nye energiløsninger. Fulltekst i vitenarkiv
• Rekstad, John Bernhard (2008). Energisituasjonen - trusler og muligheter. Fulltekst i vitenarkiv
• Rekstad, John Bernhard (2008). Næringslivets kompetansebehov innen solenergi. Fulltekst i vitenarkiv
• Rekstad, John Bernhard (2008). Solenergi og klima. Fulltekst i vitenarkiv
• Rekstad, John Bernhard (2008). Polymers in Solar Systems. Fulltekst i vitenarkiv
• Rekstad, John Bernhard (2008). Eneregi, tjenester, komfort. Fulltekst i vitenarkiv
• Rekstad, John Bernhard (2008). Solvarme, demonstrasjon av fungerende solvarmesystem. Fulltekst i vitenarkiv
• Meir, Michaela Georgine; Rekstad, John Bernhard; Gjessing, Jo & Rumler, Nele (2008). Overheating protection of polymeric solar collectors by triggered ventilation. Fulltekst i vitenarkiv
• Meir, Michaela Georgine & Rekstad, John Bernhard (2008). IEA-SHC Task 39: Polymeric solar thermal Collectors - State of the Art. Fulltekst i vitenarkiv
• Rekstad, John Bernhard (2008). Fang sol og spar strøm. [Journal]. VG. Fulltekst i vitenarkiv
• Rekstad, John Bernhard (2008). Oppvarmet med kosmisk energi. [Journal]. Folkevett no 5, 2008. Fulltekst i vitenarkiv
• Rekstad, John Bernhard (2008). Mot 100% vekst for solstrøm. [Journal]. Elektro Energiteknikk. Fulltekst i vitenarkiv
• Rekstad, John Bernhard (2008). "All polymer" solar collectors for medium temperature applications. Fulltekst i vitenarkiv
• Rekstad, John Bernhard (2008). Results from solar thermal energy reserach at the University of Oslo. Fulltekst i vitenarkiv
• Siem, Sunniva; Guttormsen, Magne Sveen; Chankova, Rositsa; Larsen, Ann-Cecilie; Rekstad, John Bernhard & Syed, Naeem Ul Hasan [Vis alle 10 forfattere av denne artikkelen] (2007). Level densities and gamma-strength functions in rare earth nuclei. Fulltekst i vitenarkiv
• Rekstad, John Bernhard (2007). Termisk solenergi, energibruk i bygg, vannbårne varme- og kjølesystemer. Fulltekst i vitenarkiv
• Larsen, Ann-Cecilie; Chankova, Rositsa; Guttormsen, Magne Sveen; Ingebretsen, Finn; Lönnroth, Tom & Messelt, Svein [Vis alle 11 forfattere av denne artikkelen] (2007). Puzzling gamma-ray strength functions in 44,45Sc and 50,51V. Fulltekst i vitenarkiv
• Rekstad, John Bernhard (2007). Polymers from a market perspective, ideas for future development. Fulltekst i vitenarkiv
• Rekstad, John Bernhard (2007). Energy Physics - Solar Energy. Fulltekst i vitenarkiv
• Rekstad, John Bernhard (2007). Innovative solar thermal systems in Norway. Fulltekst i vitenarkiv Vis sammendrag

  Two perspectives are necessary for a presentation of solar energy in Norway. One perspective is the use of solar energy, - thermal and PV in the Norwegian market. The other perspective is the development of industry and commerce related to solar energy.

• Rekstad, John Bernhard; Meir, Michaela Georgine; Olivares, Lopez Andres F & Gjessing, Jo (2007). Polymeric materials in solar collectors. Fulltekst i vitenarkiv Vis sammendrag

  The paper outlines the impact of temperature on polymeric solar thermal collectors, and methods to reduce the thermal degradation. If solar thermal shall play the role in the future that is desired and forecasted, new materials will be required. Both the IEA's-Solar heating and Cooling Programme and EU’s 7 Framework Programme focus on polymeric collectors. The main barrier for a full breakthrough for the polymer solution is the temperature sustainability in situations where stagnation temperatures occur. This problem is significantly smaller for Nordic climate than at for latitudes further south. The strong engagement revealed by leading industries in the polymer sector can be an inspiration and opportunity for scientific and technical Nordic research groups to take a frontier position in this field.

• Meir, Michaela Georgine; Rekstad, John Bernhard & Meek, Frode (2007). Energimålinger i boligene i Bjørnveien 119. Arkitektur N. ISSN 1504-7628. s. 49–49. Fulltekst i vitenarkiv
• Rekstad, John Bernhard (2006). POWER THE FUTURE - Future energy sources. Fulltekst i vitenarkiv
• Rekstad, John Bernhard & Meir, Michaela Georgine (2006). Disse husene varmes opp av sola. [Journal]. Bonytt . Fulltekst i vitenarkiv
• Siem, Sunniva; Guttormsen, Magne; Larsen, Ann-Cecilie; Rekstad, John Bernhard; Schiller, Andreas & Ødegård, Stein Westad [Vis alle 9 forfattere av denne artikkelen] (2006). Level densities and gamma-ray strength functions in Sm isotopes. Fulltekst i vitenarkiv
• Guttormsen, Magne; Agvaanluvsan, Undraa; Chankova, Rositsa; Larsen, Ann-Cecilie; Rekstad, John Bernhard & Schiller, Andreas [Vis alle 9 forfattere av denne artikkelen] (2006). Entropy in Nuclei. Fulltekst i vitenarkiv
• Siem, Sunniva; Guttormsen, Magne; Larsen, Ann-Cecilie; Rekstad, John Bernhard; Syed, Naeem Ul Hasan & Schiller, Andreas [Vis alle 8 forfattere av denne artikkelen] (2006). Level densities and gamma-ray strength functions in Sm isotopes. Fulltekst i vitenarkiv
• Rekstad, John Bernhard (2006). Oppsving for solenergi? Fulltekst i vitenarkiv
• Dursun, Aylin Maria; Rekstad, John Bernhard & Meir, Michaela Georgine (2013). Natural circulating flat plate collectors : Investigations of a new material and performance simulations. Universitetet i Oslo. Fulltekst i vitenarkiv Vis sammendrag

  Solar energy can be utilized to heat water with the use of flat plate collectors. Effort is made to reduce the cost of solar water heating technology in order to make it economically competitive to conventional energy. An absorber material is tested on component level and performance related aspects are studied. The material has a lower price than the polymer materials currently used in glazed collectors, and therefore it has the potential to lower the cost of solar flat plate collectors. The performance related aspects are tested on a partially glazed, natural circulating flat plate collector, referred to as the Duo-Collector. The aim of letting the collector be partially glazed is to prevent the heat carrier from boiling. Samples cut from an extruded absorber sheet were exposed to 140 degrees Celsius and 150 degrees Celsius for different periods of time. These were used to map the mechanical properties of the material. The samples exposed to 150 degrees Celsius were used to map dimensional and optical changes. The results from the material-related studies on component level show that no failure occurs for any of the ageing periods which were realized in the time frame of the present work. The extruded absorber sheet has a sufficiently high absorptance and dimensional stability. These findings have strengthened the material's position as a candidate for use in solar thermal applications. The performance of the Duo-Collector has been simulated with MATLAB. It is found that the system is suitable as a method for preventing the fluid in the collector from boiling. The efficiency of such a system was also investigated. For low operating temperatures the efficiency of a Duo-Collector is approximately equal to the efficiency of a fully glazed or an unglazed collector. The efficiency of all the collectors decrease with increasing operating temperatures, and the efficiency of the Duo-Collector is between that of a fully glazed and that of an unglazed collector for all operating temperatures above approximately 10 degrees Celsius. Under certain circumstances the Duo-Collector can cool the water. This effect needs to be investigated further. Since only steady-state conditions are studied in this work, further analysis must be performed to compare how the Duo-Collector performs for different applications.

• Lòpez, Andres Franklin Olivares; Rekstad, John Bernhard & Meir, Michaela Georgine (2008). Service life estimation for a polymeric solar absorber. Universitetet i Oslo. Fulltekst i vitenarkiv
• Kristoffersen, Astrid Rusås; Rekstad, John Bernhard & Aurlien, Tormod (2006). Heat and mass transfer in buildings. Universitetet i Oslo. Fulltekst i vitenarkiv

Se alle arbeider i NVA