• Wyszukiwanie zaawansowane
  • Kategorie
  • Kategorie BISAC
  • Książki na zamówienie
  • Promocje
  • Granty
  • Książka na prezent
  • Opinie
  • Pomoc
  • Załóż konto
  • Zaloguj się

 » książki  » Technology & Engineering - Power Resources - Alternative & Renewable

zaloguj się | załóż konto
Logo Krainaksiazek.pl

koszyk

konto

szukaj
topmenu
Księgarnia internetowa
Szukaj
Książki na zamówienie
Promocje
Granty
Książka na prezent
Moje konto
Pomoc
 
 
Wyszukiwanie zaawansowane
Pusty koszyk
Bezpłatna dostawa dla zamówień powyżej 20 złBezpłatna dostawa dla zamówień powyżej 20 zł

Kategorie główne

• Nauka
 [2946600]
• Literatura piękna
 [1856966]

  więcej...
• Turystyka
 [72221]
• Informatyka
 [151456]
• Komiksy
 [35826]
• Encyklopedie
 [23190]
• Dziecięca
 [619653]
• Hobby
 [140543]
• AudioBooki
 [1577]
• Literatura faktu
 [228355]
• Muzyka CD
 [410]
• Słowniki
 [2874]
• Inne
 [445822]
• Kalendarze
 [1744]
• Podręczniki
 [167141]
• Poradniki
 [482898]
• Religia
 [510455]
• Czasopisma
 [526]
• Sport
 [61590]
• Sztuka
 [243598]
• CD, DVD, Video
 [3423]
• Technologie
 [219201]
• Zdrowie
 [101638]
• Książkowe Klimaty
 [124]
• Zabawki
 [2473]
• Puzzle, gry
 [3898]
• Literatura w języku ukraińskim
 [254]
• Art. papiernicze i szkolne
 [8170]
Kategorie szczegółowe BISAC

Kategoria BISAC: Technology & Engineering >> Power Resources - Alternative & Renewable

ilość książek w kategorii: 4511

Wyświetl książki:
Dostępne języki:
Cena:
od:
do:
ilość na stronie:


 Biofuels for Road Transport: A Seed to Wheel Perspective Reijnders, Lucas 9781849968232 Springer
Biofuels for Road Transport: A Seed to Wheel Perspective

ISBN: 9781849968232 / Angielski / Miękka / 170 str.

ISBN: 9781849968232/Angielski/Miękka/170 str.

Termin realizacji zamówienia: ok. 5-8 dni roboczych.
Springer

Biofuels for Road Transport: A Seed to Wheel Perspective provides a review of the history, the current status and perspectives for biofuels used in road transport, across the full seed-to-wheel life cycle of these fuels. Successive chapters cover the history of biofuels; the first- and second-generation liquid fuels and biofuels for powering electric vehicles; fossil fuel replacement, land requirement, greenhouse gas balances and environmental burdens of ethanol, esters derived from fatty acids ( biodiesel ), Fischer-Tropsch diesel and HTU diesel; competing technologies (fossil...

Biofuels for Road Transport: A Seed to Wheel Perspective provides a review of the history, the current status and perspectives for biofuel...

cena: 403,47 zł

 Advanced Methods of Solid Oxide Fuel Cell Modeling Jaros?aw Milewski Konrad ?Wirski Massimo Santarelli 9780857292612 Not Avail
Advanced Methods of Solid Oxide Fuel Cell Modeling

ISBN: 9780857292612 / Angielski / Twarda / 217 str.

ISBN: 9780857292612/Angielski/Twarda/217 str.

Termin realizacji zamówienia: ok. 5-8 dni roboczych.
Jaroslaw Milewski; Konrad ?Wirski; Massimo Santarelli
Fuel cells are widely regarded as the future of the power and transportation industries. This book provides a comprehensive description of modern fuel cell theory and a guide to the mathematical modeling of SOFCs, with particular emphasis on the use of ANNs.
Fuel cells are widely regarded as the future of the power and transportation industries. This book provides a comprehensive description of modern fuel...
cena: 403,47 zł

 Hydrogen-Based Autonomous Power Systems: Techno-Economic Analysis of the Integration of Hydrogen in Autonomous Power Systems Lymberopoulos, Nicolaos 9781849967624 Springer
Hydrogen-Based Autonomous Power Systems: Techno-Economic Analysis of the Integration of Hydrogen in Autonomous Power Systems

ISBN: 9781849967624 / Angielski / Miękka / 188 str.

ISBN: 9781849967624/Angielski/Miękka/188 str.

Termin realizacji zamówienia: ok. 5-8 dni roboczych.
Nicolaos Lymberopoulos; Emmanuel Zoulias

"Hydrogen-based Autonomous Power Systems" analyses the introduction of hydrogen energy technologies in autonomous power systems based on renewable energy sources (RES). The book contains a review of hydrogen technologies suitable for RES-based autonomous power systems, presents already-existing demonstration hydrogen-based power systems, and provides concrete examples for the integration of hydrogen technologies into existing autonomous power systems. Technical and economic analyses of hydrogen-based power systems are included, with illustrations and graphs, which are a useful tool for...

"Hydrogen-based Autonomous Power Systems" analyses the introduction of hydrogen energy technologies in autonomous power systems based on renewable ...

cena: 403,47 zł

 Solar Energy Fundamentals and Modeling Techniques: Atmosphere, Environment, Climate Change and Renewable Energy Sen, Zekai 9781849967341 Springer
Solar Energy Fundamentals and Modeling Techniques: Atmosphere, Environment, Climate Change and Renewable Energy

ISBN: 9781849967341 / Angielski / Miękka / 276 str.

ISBN: 9781849967341/Angielski/Miękka/276 str.

Termin realizacji zamówienia: ok. 5-8 dni roboczych.
Zekai Sen

Solar irradiation is the fundamental initiator of the different renewable energy alternatives, including wind, wave, hydrogen and biomass energy sources. Solar Energy Fundamentals and Modelling Techniques presents the methods of quantitative determination of solar irradiation incident amount on a surface on the Earth. The book collects together material from the current literature in atmospheric environmental sciences, climate change, meteorology, engineering and renewable energy, liberally illustrated by diagrams and worked examples.

Solar Energy Fundamentals...

Solar irradiation is the fundamental initiator of the different renewable energy alternatives, including wind, wave, hydrogen and biomass energy so...

cena: 726,29 zł

 Ocean Energy: Tide and Tidal Power Charlier, R. H. 9783642096754 Springer
Ocean Energy: Tide and Tidal Power

ISBN: 9783642096754 / Angielski / Miękka / 262 str.

ISBN: 9783642096754/Angielski/Miękka/262 str.

Termin realizacji zamówienia: ok. 5-8 dni roboczych.
Springer

Engineers' dreams and fossil energy replacement schemes can come true. Man has been tapping the energy of the sea to provide power for his industries for centuries. Tidal energy combined with that of waves and marine winds rank among those most successfully put the work. Large scale plants are capital intensive but smaller ones, particularly built in China, have proven profitable. Since the initiation of the St Malo project in France, similar projects have gone into active service where methods have been devised to cut down on costs, new types of turbines developed and cost competitiveness...

Engineers' dreams and fossil energy replacement schemes can come true. Man has been tapping the energy of the sea to provide power for his industri...

cena: 605,23 zł

 Hydrogen Storage Materials: The Characterisation of Their Storage Properties Broom, Darren P. 9780857292209 Not Avail
Hydrogen Storage Materials: The Characterisation of Their Storage Properties

ISBN: 9780857292209 / Angielski / Twarda / 260 str.

ISBN: 9780857292209/Angielski/Twarda/260 str.

Termin realizacji zamówienia: ok. 5-8 dni roboczych.
Darren P. Broom

The problem of storing hydrogen safely and effectively is one of the major technological barriers currently preventing the widespread adoption of hydrogen as an energy carrier and the subsequent transition to a so-called hydrogen economy. Practical issues with the storage of hydrogen in both gas and liquid form appear to make reversible solid state hydrogen storage the most promising potential solution. Hydrogen Storage Materials addresses the characterisation of the hydrogen storage properties of the materials that are currently being considered for this purpose.

The...

The problem of storing hydrogen safely and effectively is one of the major technological barriers currently preventing the widespread adoption of h...

cena: 605,23 zł

 Rational Exuberance for Renewable Energy: An Economic Analysis Sunderasan, Srinivasan 9780857292117 Not Avail
Rational Exuberance for Renewable Energy: An Economic Analysis

ISBN: 9780857292117 / Angielski / Twarda / 113 str.

ISBN: 9780857292117/Angielski/Twarda/113 str.

Termin realizacji zamówienia: ok. 5-8 dni roboczych.
Srinivasan Sunderasan

"Rational Exuberance for Renewable Energy" is a beyond-the-hype account of the underlying issues that encourage or plague widespread dissemination of renewable energy (RE) technologies. Renewable energy operates in the real world, and it cannot be assumed that the conventional theories and incentive structures of economics and business do not apply. The author argues that grants and subsidies could be provided to support research, development and technology improvement efforts, but should not be employed as an instrument of state policy to intervene in specific markets. It is important to...

"Rational Exuberance for Renewable Energy" is a beyond-the-hype account of the underlying issues that encourage or plague widespread dissemination ...

cena: 403,47 zł

 Power Conversion of Renewable Energy Systems Ewald F. Fuchs Mohammad A. S. Masoum 9781441979780 Not Avail
Power Conversion of Renewable Energy Systems

ISBN: 9781441979780 / Angielski / Twarda / 692 str.

ISBN: 9781441979780/Angielski/Twarda/692 str.

Termin realizacji zamówienia: ok. 5-8 dni roboczych.
Ewald F. Fuchs; Mohammad A. S. Masoum

Power Conversion of Renewable Energy Systems presents an introduction to conventional energy conversion components and systems, as well as those related to renewable energy. This volume introduces systems first, and then in subsequent chapters describes the components of energy systems in detail. Readers will find examples of renewable and conventional energy and power systems, including energy conversion, variable-speed drives and power electronics, in addition to magnetic devices such as transformers and rotating machines. Applications of PSpice, MATLAB, and Mathematica are also...

Power Conversion of Renewable Energy Systems presents an introduction to conventional energy conversion components and systems, as well as t...

cena: 201,72 zł

 Sustainability in Energy and Buildings: Results of the Second International Conference in Sustainability in Energy and Buildings (Seb'10) Howlett, Robert J. 9783642173868 Not Avail
Sustainability in Energy and Buildings: Results of the Second International Conference in Sustainability in Energy and Buildings (Seb'10)

ISBN: 9783642173868 / Angielski / Twarda / 300 str.

ISBN: 9783642173868/Angielski/Twarda/300 str.

Termin realizacji zamówienia: ok. 5-8 dni roboczych.
Robert J. Howlett; Shaun H. Lee

This volume represents the proceedings of the Second International Conference on Sustainability in Energy and Buildings, SEB'10, held in the City of Brighton and Hove in the United Kingdom, and organised by KES International.

Organised by the KES International organisation, SEB'10 formed a welcome opportunity for researchers in subjects related to sustainability, renewable energy technology, and applications in the built environment to mix with other scientists, industrialists and stakeholders in the field.

SEB'10 attracted papers on a range of renewable energy...

This volume represents the proceedings of the Second International Conference on Sustainability in Energy and Buildings, SEB'10, held in the City o...

cena: 806,99 zł

 Renewable Energy: Technology, Economics and Environment Kaltschmitt, Martin 9783642089947 Springer
Renewable Energy: Technology, Economics and Environment

ISBN: 9783642089947 / Angielski / Miękka / 564 str.

ISBN: 9783642089947/Angielski/Miękka/564 str.

Termin realizacji zamówienia: ok. 5-8 dni roboczych.
Martin Kaltschmitt; Wolfgang Streicher; Andreas Wiese

This book presents the physical and technical principles of promising ways of utilising renewable energies. In this context, firstly the main characteristics of the available renewable energy streams are outlined. Subsequently, the book presents the technologies of heat provision from passive and active solar systems, ambient air, shallow geothermal energy as well as energy from deep geothermal sources. In the preceding chapters the book addresses the processes of electricity generation from solar radiation (photovoltaic and solar thermal power plant technologies), wind energy, and...

This book presents the physical and technical principles of promising ways of utilising renewable energies. In this context, firstly the main chara...

cena: 322,77 zł

 Solar Electric Power Generation - Photovoltaic Energy Systems: Modeling of Optical and Thermal Performance, Electrical Yield, Energy Balance, Effect o Krauter, Stefan C. W. 9783642068454 Springer
Solar Electric Power Generation - Photovoltaic Energy Systems: Modeling of Optical and Thermal Performance, Electrical Yield, Energy Balance, Effect o

ISBN: 9783642068454 / Angielski / Miękka / 271 str.

ISBN: 9783642068454/Angielski/Miękka/271 str.

Termin realizacji zamówienia: ok. 5-8 dni roboczych.
Stefan C. W. Krauter

Solar electricity is a viable, environmentally sustainable alternative to the world s energy supplies. In support, Dr. Krauter thoroughly examines the various technical parameters of photovoltaic systems. Study of performance and yield (including optical, thermal, and electrical parameters and interfaces) are analyzed. The net energy balance of photovoltaic systems from production, operation and maintenance, to recycling is explored. Professor Krauter demonstrates how the importance of accurate yield calculations, optimal system performance, and new prototypes aid in cost reductions. The...

Solar electricity is a viable, environmentally sustainable alternative to the world s energy supplies. In support, Dr. Krauter thoroughly examines ...

cena: 527,92 zł

 Physical Approach to Short-Term Wind Power Prediction Matthias Lange Ulrich Focken 9783642065088 Springer
Physical Approach to Short-Term Wind Power Prediction

ISBN: 9783642065088 / Angielski / Miękka / 208 str.

ISBN: 9783642065088/Angielski/Miękka/208 str.

Termin realizacji zamówienia: ok. 5-8 dni roboczych.
Matthias Lange; Ulrich Focken
Triggered by a discussion on the nature of future electricity supplies, wind - ergy utilisation has boomed dramatically, ?rst in the United States of America and Denmark and later in Germany and Spain. Thanks to state subsidies, it has within 15 years overtaken the volume of the classic renewable hydro-power, and today it accountsforabout5%ofelectricitygeneration. Twofactorssetoffthisdevelopment: anawarenessofthelimitedavailabilityof fossilfuelsandtherecognitionthatinthe19thand20thcenturiesthemassiverelease of fossil CO had kicked off a gigantic climate experiment whose results remain 2...
Triggered by a discussion on the nature of future electricity supplies, wind - ergy utilisation has boomed dramatically, ?rst in the United States of ...
cena: 443,82 zł

 Finite Element Analysis of Hyperbolic Cooling Towers Seyyed Mohammed Niku 9783540167389 Springer
Finite Element Analysis of Hyperbolic Cooling Towers

ISBN: 9783540167389 / Angielski / Miękka / 216 str.

ISBN: 9783540167389/Angielski/Miękka/216 str.

Termin realizacji zamówienia: ok. 5-8 dni roboczych.
Seyyed Mohammed Niku
The analysis of thin shells of revolution in general has always occupied an important place in the theory of structures, and recently the problem of hyperbolic cooling towers has attracted many investigators due to the wide use of such shells in industry. Until the early 1960's these towers were of moderate size, probably not exceeding 76m (250ft) height. In this range, the structural safety and stability were not of primary concern because, the minimum wall thickness and reinforcement were sufficient to provide the required safety. It was not necessary to use very rigorous methods to analyse...
The analysis of thin shells of revolution in general has always occupied an important place in the theory of structures, and recently the problem of h...
cena: 403,47 zł

 Solar Thermal Central Receiver Systems: Proceedings of the Third International Workshop June 23-27, 1986, Konstanz, Federal Republic of Germany Becker, Manfred 9783540170525 Springer
Solar Thermal Central Receiver Systems: Proceedings of the Third International Workshop June 23-27, 1986, Konstanz, Federal Republic of Germany

ISBN: 9783540170525 / Angielski / Miękka / 572 str.

ISBN: 9783540170525/Angielski/Miękka/572 str.

Termin realizacji zamówienia: ok. 5-8 dni roboczych.
Manfred Becker
These volumes present the Proceedings of the "Third Interna- tional Workshop on Solar Thermal Central Receiver Systems" or- ganized by the DFVLR and held in Konstanz, Federal Republic of Germany, June, 1986. The Workshop was the continuation of the conferences in Claremont, USA, 1982 and in Varese, Italy, 1984 on the subject of "Central Receiver Projects" and of the con- ferences in Stuttgart, Federal Republic of Germany, 1983 and in Atlanta, USA, 1985 on the subject of "High Temperature Solar Technology and Application." The success of the Workshop was indicated by the participation of 113...
These volumes present the Proceedings of the "Third Interna- tional Workshop on Solar Thermal Central Receiver Systems" or- ganized by the DFVLR and h...
cena: 403,47 zł

 Solar Thermal Energy Utilization: German Studies on Technology and Applications. Volume 2: Technologies of Heat Exchangers (Receiver/Reformer) and Sto Becker, Manfred 9783540180319 Springer
Solar Thermal Energy Utilization: German Studies on Technology and Applications. Volume 2: Technologies of Heat Exchangers (Receiver/Reformer) and Sto

ISBN: 9783540180319 / Angielski / Miękka / 323 str.

ISBN: 9783540180319/Angielski/Miękka/323 str.

Termin realizacji zamówienia: ok. 5-8 dni roboczych.
Manfred Becker
The energy crisis in 1973 and 1979 initiated a great number of activities and programs for low and high temperature applica tion of solar energy. Synthetic fuels and chemicals produced by solar energy is one of them, where temperatures in the range of o 600-1000 e or even higher are needed. In principle such high temperatures can be produced in solar towers. For electricity production, the feasibility and operation of solar tower plants has been examined during the SSPS - project (Small Solar Power System) in Almeria, Spain. The objective of Solar Thermal Energy Utilization is to extend the...
The energy crisis in 1973 and 1979 initiated a great number of activities and programs for low and high temperature applica tion of solar energy. Synt...
cena: 201,72 zł

 Solar Thermal Energy Utilization: German Studies on Technology and Application. Volume 3: Solar Thermal Energy for Chemical Processes Becker, Manfred 9783540180326 Springer
Solar Thermal Energy Utilization: German Studies on Technology and Application. Volume 3: Solar Thermal Energy for Chemical Processes

ISBN: 9783540180326 / Angielski / Miękka / 767 str.

ISBN: 9783540180326/Angielski/Miękka/767 str.

Termin realizacji zamówienia: ok. 5-8 dni roboczych.
Manfred Becker
The energy crisis in 1973 and 1979 initiated a great number of activities and programs for low and high temperature applica tion of solar energy. Synthetic fuels and chemicals produced by solar energy is one of them, where temperatures in the range of 600-1000 C or even higher are needed. In principle such high temperatures can be produced in solar towers. For electricity production, the feasibility and operation of solar tower plants has been examined during the SSPS - project (Small Solar Power System) in Almeria, Spain. The objective of Solar Thermal Energy Utilization is to extend the...
The energy crisis in 1973 and 1979 initiated a great number of activities and programs for low and high temperature applica tion of solar energy. Synt...
cena: 201,72 zł

 Energy Systems in the Era of Energy Vectors: A Key to Define, Analyze and Design Energy Systems Beyond Fossil Fuels Orecchini, Fabio 9780857292438 Springer
Energy Systems in the Era of Energy Vectors: A Key to Define, Analyze and Design Energy Systems Beyond Fossil Fuels

ISBN: 9780857292438 / Angielski / Twarda / 364 str.

ISBN: 9780857292438/Angielski/Twarda/364 str.

Termin realizacji zamówienia: ok. 5-8 dni roboczych.
Fabio Orecchini; Vincenzo Naso

What lies beyond the era of fossil fuels? While most answers focus on different primary energy resources, Energy Systems in the Era of Energy Vectors provides a completely new approach.

Instead of providing a traditional consumption analysis of classical primary energy resources such as oil, coal, nuclear power and gas, Energy Systems in the Era of Energy Vectors describes and assesses energy technologies, markets and future strategies, focusing on their capacity to produce, exchange, and use energy vectors. Special attention is given to the renewable energy resources...

What lies beyond the era of fossil fuels? While most answers focus on different primary energy resources, Energy Systems in the Era of Energy Ve...

cena: 605,23 zł

 PEM Fuel Cells with Bio-Ethanol Processor Systems: A Multidisciplinary Study of Modelling, Simulation, Fault Diagnosis and Advanced Control Basualdo, Marta S. 9781849961837 Springer
PEM Fuel Cells with Bio-Ethanol Processor Systems: A Multidisciplinary Study of Modelling, Simulation, Fault Diagnosis and Advanced Control

ISBN: 9781849961837 / Angielski / Twarda / 461 str.

ISBN: 9781849961837/Angielski/Twarda/461 str.

Termin realizacji zamówienia: ok. 5-8 dni roboczych.
Marta S. Basualdo; Rachid Outbib; Diego Feroldi

An apparently appropriate control scheme for PEM fuel cells may actually lead to an inoperable plant when it is connected to other unit operations in a process with recycle streams and energy integration. PEM Fuel Cells with Bio-Ethanol Processor Systems presents a control system design that provides basic regulation of the hydrogen production process with PEM fuel cells. It then goes on to construct a fault diagnosis system to improve plant safety above this control structure.

PEM Fuel Cells with Bio-Ethanol Processor Systems is divided into two parts: the first covers...

An apparently appropriate control scheme for PEM fuel cells may actually lead to an inoperable plant when it is connected to other unit operations ...

cena: 605,23 zł

 The Magnesium Civilization : An Alternative New Source of Energy to Oil Takashi Yabe Tatsuya Yamaji 9789814303651 Pan Stanford Publishing
The Magnesium Civilization : An Alternative New Source of Energy to Oil

ISBN: 9789814303651 / Angielski / Twarda / 147 str.

ISBN: 9789814303651/Angielski/Twarda/147 str.

Termin realizacji zamówienia: ok. 5-8 dni roboczych.
Takashi Yabe; Tatsuya Yamaji

This book covers how magnesium can be used for metal-air-fuel cells for automobiles and powerplants. The automobile with Zinc-air-fuel cell achieved 600km mileage in 2003 and Magnesium-air-fuel cell can give 3 times more energy which is 7.5 times more effective than Lithium-ion battery. Solar-pumped laser regenerates metal Magnesium from combusted Magnesium oxide. The book covers how low-cost desalination with solar-power will be a promising solution to the global water shortage.


This book covers how magnesium can be used for metal-air-fuel cells for automobiles and powerplants. The automobile with Zinc-air-fuel cell achieve...

cena: 185,30 zł

 Solar Thermal Energy Utilization. German Studies on Technology and Application: Volume 6: Final Reports 1990 Becker, Manfred 9783540548362 Not Avail
Solar Thermal Energy Utilization. German Studies on Technology and Application: Volume 6: Final Reports 1990

ISBN: 9783540548362 / Angielski / Miękka / 455 str.

ISBN: 9783540548362/Angielski/Miękka/455 str.

Termin realizacji zamówienia: ok. 5-8 dni roboczych.
Manfred Becker; Karl-Heinz Funken; Gernot Schneider
The German R + D program "Solares Testzentrum Almeria" (SOTA) provides the scientific basis for the realization of advanced solar technologies including facility modifica-tions, component tests and new lines of development. One of the working packages, WP 300, addresses the "Scientific Support" by the performance of pre-paratory studies, exploratory laboratory activities and quali- fied expertise. Universities, Research Institutes and Company R + D Entities in Germany are enabled to treat the following aspects: * Meteorological, system and cost investigations, * Development of important...
The German R + D program "Solares Testzentrum Almeria" (SOTA) provides the scientific basis for the realization of advanced solar technologies includi...
cena: 201,72 zł

Pierwsza Podprzednia  10  11  12  Następna Ostatnia

Facebook - konto krainaksiazek.pl



Opinie o Krainaksiazek.pl na Opineo.pl

Partner Mybenefit

Krainaksiazek.pl w programie rzetelna firma Krainaksiaze.pl - płatności przez paypal

Czytaj nas na:

Facebook - krainaksiazek.pl
  • książki na zamówienie
  • granty
  • książka na prezent
  • kontakt
  • pomoc
  • opinie
  • regulamin
  • polityka prywatności

Zobacz:

  • Księgarnia czeska

  • Wydawnictwo Książkowe Klimaty

1997-2025 DolnySlask.com Agencja Internetowa

© 1997-2022 krainaksiazek.pl
     
KONTAKT | REGULAMIN | POLITYKA PRYWATNOŚCI | USTAWIENIA PRYWATNOŚCI
Zobacz: Księgarnia Czeska | Wydawnictwo Książkowe Klimaty | Mapa strony | Lista autorów
KrainaKsiazek.PL - Księgarnia Internetowa
Polityka prywatnosci - link
Krainaksiazek.pl - płatnośc Przelewy24
Przechowalnia Przechowalnia