H2POWER: Development of a methodology to calculate life cycle cost of small and medium-scale hydrogen systems
Abstract At this time, hydrogen-based power plants and large hydrogen production facilities are capital intensive and unable to compete financially against hydrocarbon-based energy production facilities. An option to overcome this problem and foster the introduction of hydrogen technology is to introduce small and medium-scale applications such as residential and community hydrogen refueling units. Such units could potentially be used to generate both electricity and heat for the home, as well as hydrogen fuel for the automobile. Cost modeling for the integration of these three forms of energy presents several methodological challenges. This is particularly true since the technology is still in the development phase and both the financial and the environmental cost must be calculated using mainly secondary sources. In order to address these issues and aid in the design of small and medium-scale hydrogen systems, this study presents a computer model to calculate financial and environmental costs of this technology using different hydrogen pathways. The model can design and compare hydrogen refueling units against hydrocarbon-based technologies, including the “gap” between financial and economic costs. Using the methodology, various penalties and incentives that can foster the introduction of hydrogen-based technologies can be added to the analysis to study their impact on financial cost.
GÜNES HAVUZLARININ KULLANIM ÖMRÜ MALİYET ANALİZİ
Gunes havuzlari, gunes enerjisini uzun sure boyunca toplayan ve depolayan sistemlerdir. Bu sistemlerin ulke genelinde daha yaygin bir sekilde kullanilmalari icin, fiziksel ozelliklerinin yaninda gunes enerjisinden sicak su uretimi ve depolamasinin ekonomik olup olmadiklarinin da bilinmesi gerekir. Kullanim omru maliyet analizi ozel proseslerin veya kiyaslamasi yapilacak proseslerin cevresel etkilerini tanimlayan ve degerlendiren bir sistematik analitik metottur. Sistemin maliyetini belirlemek icin; kaynak tuketimini, enerji kullanimini, malzeme ve enerji dengelerini, ham maddeleri kullanilabilir urunlere cevirme operasyonlarinda besikten mezara seklinde bir konu olarak ele alir. Bu calismada; 3,5x3,5 m2 alanli ve 2 m derinliginde bir gunes havuzunun yansitici kapakli ve kapaksiz olmasi halinde havuzun kullanim omru maliyet analizi yapilmis ve Goller Bolgesi sartlarinda bu gunes havuzundan alinabilecek enerji miktari bulunmustur.
Denitrification of PVA-immobilized denitrifying photosynthetic bacterium, Rhodobacter sphaeroides
Abstract A newly isolated denitrifying strain, Rhodobacter sphaeroides NII2 was immobilized in polyvinyl alcohol (PVA) gel, and the properties of the cells in the gel were examined. The immobilized cells had low or almost no denitrification activity, but the cells were activated by incubation in light with culture medium for denitrification containing 0.5% nitrate and no other nitrogen source. Cells grown in the dark were activated by incubation at an earlier stage and to a higher rate than the light-grown cells. The activation was markedly enhanced in the PVA gel with a low cell concentration. The immobilized cells consumed nitrate with a temporary accumulation of NO 2 and evolved nitrogen gas. The immobilized cells could use various organic compounds as electron donors for denitrification. Thus, the immobilized cells were applied to a continuous treatment of synthetic wastewater using an aparatus devised by this laboratory. The results showed an efficient removal of NO 3 -N from the test water.