Optical interference coatings for coloured building integrated photovoltaic modules: Predicting and optimising visual properties and efficiency

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Norge etter 22. juli

"At the time of this book’s publication, almost seven years have passed since the dramatic and brutal terror attacks at Norway’s Government Headquarters in Oslo and the island of Utøya on 22 July 2011. How have we coped during this time? Which values have been important? Have we managed to protect the ideals of democracy, openness and humanity? And not least: Who is this ""we"" that we are referring to? This scholarly anthology includes articles from researchers associated with the project NECORE (Negotiating Values: Collective Identities and Resilience after 22 July) and other researchers whose work is closely associated with the project. They give us insights, opinions and sharp perspectives on not just 22 July, but also about Norway today, about values, identities and resilience in Norwegian society in the wake of the terror attacks. An important backdrop for the book and the project is the assertion that, as the events themselves recede into the past, it is even more important to focus on what the terror events have led to and how we can learn from them. In a world where terrorism has become an all too common part of political reality, it is crucial that we understand how we ought to think about terror, and how we as a society encounter it.

Cesarean delivery on maternal request: Can the ethical problem be solved by the principlist approach?

In this article, we use the principlist approach to identify, analyse and attempt to solve the ethical problem raised by a pregnant woman's request for cesarean delivery in absence of medical indications

Performance of Daylight Redirecting Venetian Blinds for Sidelighted Spaces at High Latitudes

The main topic of this thesis is daylight in buildings. More specifically, the thesis presents studies on the performance characteristics of venetian blinds used on the interior side of vertical windows. A particular emphasis is put on the daylighting properties of different blind types, and the performance of daylight redirecting blinds is compared to the performance of traditional white blinds. Three factors are highly important for daylight in buildings: the daylight source, the optical properties of the fenestration or daylighting system, and the characteristics of the architectural space that receives the daylight. Earlier works on daylighting systems in buildings have often documented the daylight levels and the daylight distribution within the space. With that approach it can be hard to pinpoint exactly why one daylighting system performs differently from another. For the work presented here it has been a goal to focus on the properties of the fenestration system itself, while operating under various daylight conditions that are relevant for high latitudes. Some assumptions have been made regarding the architectural space (sidelighted with an elevated daylight opening), but apart from this it has been sought to describe the system performance more or less independently from the architectural space. This approach can be compared to the approach that has been used in the field of electric lighting. There, luminaries are typically specified by performance characteristics that are not depending on the space in which they are to be applied. For electric luminaries, photometric properties such as luminous flux, light distribution and light output ratio are commonly used to describe the performance of the luminaire, and these values are independent of the space where the luminaire is to be used. In other words, in this thesis, the venetian blind system is treated more or less as a “daylight luminaire”. The main tool applied to analyse the photometric properties of the “daylight luminaire” is Monte Carlo forward ray tracing. The software TracePro is used extensively for this purpose. This software tool is tailor-made for analysing optical systems (including luminaries). Unfortunately, daylight sources are not available in TracePro. For this reason, a substantial effort was made in order to generate TracePro light sources that represent the light from ground, sky and sun. However, once these sources were established and validated, many positive features of the program could be utilised with good effect in order to quantify a variety of different photometric characteristics (e.g. transmittance, light distribution and luminance) of venetian blind systems. In order to analyse these characteristics in a systematic manner the fundamental geometrical properties of venetian blinds need to be understood and these properties have therefore been derived and described. A new evaluation method for daylight redirection systems is presented in this thesis. This method is based on quantification of performance metrics already applied for such systems combined with new performance indicators suggested on the basis of literature findings as well as own studies of venetian blind performance. The main goal of the new method is to provide a tool that can be used to indicate performance of a particular system with respect to 8 different important criteria that are determined by the properties of the daylighting system: (1) supply of daylight, (2) room darkening, (3) light distribution, (4) glare protection, (5) outward view, (6) privacy protection, (7) solar heat supply, and (8) overheating protection. Star diagrams are used to provide a graphical illustration of the performance of the systems, where each of the 8 star points represents one of the 8 performance criteria used to evaluate the system. The new evaluation method has been applied in order to compare the performance of traditional white blinds with that of daylight redirecting blinds. The results show that, when both blinds are operated in the semi-closed position, the performance is roughly the same for all of the performance criteria considered. However, when both blind types are operated in the open blind position, the daylight redirecting blind can perform better with respect to daylight supply and light distribution. The results presented in this thesis also show that these benefits can be obtained without worsening the performance with respect to the other criteria. The performance of blinds has been studied for daylight conditions that are representative for high latitudes. It has sometimes been argued that, due to the typical low sun conditions, especially during the winter months, daylight redirecting blinds are less suitable at high latitudes. However, results presented in this thesis show that daylight redirecting blinds can function very well under most sun conditions that are typical for high latitudes, provided that the spacing to width ratio is carefully selected

A guide to dayligthting and solar shading systems at high latitude

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Coloured Building Integrated Photovoltaics: Influence on Energy Efficiency

Building integrated photovoltaics (BIPV) has attracted increased commercial interest in recent years due to a growing focus on efficient utilization of land area and local renewable energy generation. Aesthetic aspects must be considered when photovoltaic panels are applied as building elements. Colours can be added by reflecting some of the sunlight that otherwise could have been utilized for electricity generation. Reflectance spectra of commercial solar cell modules have been measured and analysed. Relative efficiency loss caused by the reflected solar radiation energy has been calculated. The calculated losses in efficiency based on measured spectra have been compared to model spectra with colour coordinates corresponding to RAL colours as well as more idealized monochromatic spectra. The analysis shows that the most important colour parameter affecting loss is the lightness. The second most important parameter is the hue of the colour, with green-yellow colours having the lowest loss, and pink colours resulting in the highest loss, when colours with the same lightness are compared. A Colour Performance Index (CPI) given by luminous reflectance divided by relative loss has been proposed as a figure of merit, thus allowing for a useful comparison of colours with different lightness.publishedVersio

Pixelization approach for façade integrated coloured photovoltaics-with architectural proposals in city context of Trondheim, Norway

Façade integrated photovoltaics (FIPV) is an emerging and essential way to utilize solar energy in built environment. However, there is limited architectural study of FIPV, especially addressing the topic of colour performance. This study developed a theoretical method with pixelated colour design for integrating opaque coloured photovoltaics on building facades. The city of Trondheim in Norway was taken as a case study. Two main façade prototypes for FIPV were derived from Trondheim’s urban context. Typical hues for the two façade prototypes were selected from Trondheim’s urban colour palette, and colour harmony strategies were applied as design guidelines to generate NCS colour combinations for FIPV. Then a series of pixelated FIPV designs was proposed. The aesthetic performance of the proposed pixelated FIPV designs was tested through an online survey among architects, urban designers and laypersons from different countries. A 5-level semantic differential scaling was employed for aesthetic evaluation. The results demonstrated that the FIPV concept was widely supported by participants, while the proposed pixelated FIPV designs were aesthetically preferred and considered as coherent with urban context by the majority of participants. Besides, the energy production efficiencies of proposed designs were calculated. Pixelated coloured FIPV facades showed promising energy production efficiency (theoretically about 85–93% of black PV facades). The overall façade lightness demonstrated a much stronger influence on efficiency than hue. This study presented a promising pixelization method for FIPV design, through which a balanced FIPV performance including pleasing façade aesthetic quality, satisfied urban integration, and high energy production efficiency could be achieved.publishedVersio