No description available.

No description available.

It seems evident that the geometry of the urban form as an urban design parameter is crucial. The layout of the structure can modify the urban climate through proper design, thus improving the thermal comfort both outside and inside buildings, even reducing energy demands for heating and cooling requirements. Although solar design potentials on an architectural scale are at present well developed, the approach and the techniques applied on an urban scale are yet to be consolidated in order to promote climatic responsive urban design. This thesis is concerned with a method to evaluate solar energy in urban design. The emphasis of the thesis is to study the relationship between the urban form and solar insolation and to establish a comprehensive approach which can evaluate the urban forms, with respect to the generated shadow pattern, and can be applicable to all types of urban configurations. Among the considerations which have also been investigated, is the interrelationship between solar insolation and thermal performance of urban patterns. The thesis discusses the possible application of these forms in Palestine, in order to highlight the way that the derived results can be handled in real practice. While the analysis was mainly related to the Palestinian climate, the techniques employed may be applicable to other countries. The main structure of this thesis is arranged in two parts. The first part identifies the conceptual framework of the sustainable urban design in order to provide the reader with basic information about the subject. The principal aim of this part has been to outline the research area on which the present work was set. Secondly, parametric studies have been performed to bridge the gap in the previous studies. The parametric studies are structured into four chapters. Each study raises separate but overlapping issues and the four studies together cover the basic classified types of urban forms. The first study compares radial and rectangular forms in order to explore the solar behaviour of the radial form, as opposed to the rectangular one and to illustrate the methodology adopted in this research work to evaluate the urban forms with regard to the generated shadow patterns and thermal performance. The second study compares radial and rectangular urban canyons to clarify the influence of the self-shading effect of the radial form. The experiment evaluates the most suitable spacing between buildings to avoid overshadowing and maintain good solar accessibility. The study was also performed to determine the urban fabric that allows the achievement of high urban density under optimal solar insolation conditions. The third part contains studies related to aspects of solar insolation in bilateral types of building. The study compares different radial forms varying in the extent of their concavity to find out the one with the minimum variation of exposed areas between the two opposite facades. The final chapter of the parametric studies deals with the evaluation and analysis of the radial forms and the rectangular V-shape. This experiment aims to prove the capability of the methodology which was developed in this research, to evaluate such complex forms. Simulation studies encompass shading and thermal analyses. Based on the simulations, design recommendations were derived. The resulting framework provides a significant step forward in understanding the built environment and demonstrates the rich potential in using passive design as a means of influencing urban design. Finally, the thesis draws conclusions and identifies areas for further research into the consideration of solar energy in urban design.

Shading louvres on buildings must serve to allow maximum window insolation in winter, while have the prime function of intercepting unwanted direct solar radiation in summer; which could cause excessive solar heat gain, especially in glazed offices and commercial spaces. Studies of the effect of solar protection on heating and cooling loads show that shading strategies are climate dependent. And it is accepted today that solar protection does reduce energy use for cooling, and tends to increase heating loads. The balance between the benefits in cooling and the losses in heating is only achievable by good designs. The main focus of this research work has been in harnessing the thermal energy available within the incident solar radiation intercepted by the shading louvres; hence benefiting, from shading in terms of energy savings, as well as from the collected energy. In achieving this aim, both theoretical and experimental techniques have been utilized, as design analysis tools, in order to select a design that satisfies both the efficiency and cost criteria. A suitable collector design has, then, been identified, its thermal performance characterised, and its prototype manufactured and built. The prototype of the chosen design has been field-tested in Nottingham-England and Porto-Portugal. Finally, the characteristics of the design have been incorporated into a computer simulation scenario, in which a real office building in Winterthur-Switzerland has been analysed for its total (cooling and heating) annual energy consumption. Findings of this research work indicate that these louvres, despite certain geometrical limitations, could act as solar collectors with good energy collection characteristics. And they could contribute with substantial reductions in the overall annual energy consumption resulting from the combined effect of shading and collecting energy. This was found particularly to be the case when the collected energy is made to part-fuel, an adsorption chiller for the purpose of air-conditioning the same building.

Στην παρούσα εργασία μελετήθηκαν βιβλιογραφικά οι ενεργειακές και αισθητικές παράμετροι που συμβάλλουν στην εξοικονόμηση ενέργειας στον κτιριακό τομέα. Παράλληλα έγινε πειραματική μελέτη μιας καινοτόμου προτεινόμενης διάταξης με φακούς Fresnel για τον έλεγχο του φωτισμού και της θερμοκρασίας των εσωτερικών χώρων των κτιρίων, καθώς και τριών πειραματικών διατάξεων θερμικών ηλιακών συλλεκτών με σκοπό την εκτίμηση της απόδοσης των συλλεκτών με πολύχρωμη απορροφητική επιφάνεια σε σχέση με αυτή των μαύρων συλλέκτων και σε σχέση με το πλεονέκτημα της αισθητικής ενσωμάτωσής τους στα κτίρια. / The abstract is not available.

Στις χώρες της Ευρωπαϊκής Ένωσης ο κτιριακός τομέας απορροφά περίπου το 40% της συνολικής ενεργειακής κατανάλωσης, γεγονός που καθιστά απαραίτητο το λειτουργικό και φιλικό προς το περιβάλλον σχεδιασμό των κτιρίων, παράλληλα με τον περιορισμό των συνολικών ενεργειακών αναγκών τους για την εξοικονόμηση ενέργειας. Όσον αφορά τα ήδη υπάρχοντα κτίρια, μπορούν να γίνουν διάφορες παρεμβάσεις ώστε να επιτευχθεί η μέγιστη δυνατή εξοικονόμηση ενέργειας. Από την άλλη, η Ε.Ε.,στα πλαίσια της βιώσιμης ανάπτυξης και της προστασίας του περιβάλλοντος, έχει θέσει ως στόχο για το 2020 τα καινούρια κτίρια να είναι μηδενικών εκπομπών διοξειδίου του άνθρακα. Για την υλοποίηση του στόχου αυτού, είναι αναγκαίος ο σχεδιασμός των κτιρίων σύμφωνα με τις αρχές της βιοκλιματικής αρχιτεκτονικής, για την ελαχιστοποίηση των ενεργειακών τους αναγκών αλλά και η εφαρμογή συστημάτων Ανανεώσιμων Πηγών Ενέργειας για την παραγωγή θερμικής και ηλεκτρικής ενέργειας και την ελαχιστοποίηση έτσι των εκπομπών CO2 στην ατμόσφαιρα από τα ορυκτά καύσιμα. Στην παρούσα διπλωματική εργασία, αναπτύσσονται στρατηγικές που αποσκοπούν στην αρμονική ένταξη των κτιρίων στο φυσικό περιβάλλον, παρουσιάζονται τα θέματα εξοικονόμησης ενέργειας στα κτίρια, διατυπώνονται οι βασικές παράμετροι για την επίτευξη ολιστικής ενεργειακής κάλυψης των κτιρίων και την προετοιμασία του επόμενου βήματος σχετικά με την ενέργεια στα κτίρια για το έτος 2020 και δίνονται νέες τεχνολογικές λύσεις που αναπτύχθηκαν στο εργαστήριο ηλιακής ενέργειας, με σκοπό την βέλτιστη αξιοποίηση της ηλιακής ενέργειας και των άλλων ΑΠΕ στα κτίρια. Στα πλαίσια της πλήρους κάλυψης των κτιριακών ενεργειακών αναγκών από ΑΠΕ και της προώθησης των κτιρίων σχεδόν μηδενικής κατανάλωσης από συμβατικές ενεργειακές πηγές, μελετάται πειραματικά η συμβολή των φωτοβολταϊκών σε δυσμενή κλίση και προσανατολισμό. Εξετάζεται η συνεισφορά διάχυτων ανακλαστήρων στην ενεργειακή τους απόδοση, η επίδραση του υλικού της θερμομόνωσης και του περιορισμού των θερμικών απωλειών. Τέλος, εξετάζεται η αξιοποίηση κάθε τμήματος του κτιρίου που μπορεί να έχει θετική συμβολή στο ενεργειακό θέμα. Έτσι προτείνονται τρόποι τοποθέτησης φωτοβολταϊκών σε οριζόντιες και επικλινείς στέγες και στις προσόψεις των κτιρίων, με προσθήκη ανακλαστήρα όπου είναι δυνατό, που μπορούν να συνεισφέρουν στην επίτευξη μηδενικού ενεργειακού ισοζυγίου στα κτίρια. / In the countries of the European Union the building sector accounts for about 40% of the total energy consumption, so it is necessary that the buildings should be designed in a functional and environmentally-friendly way, in addition to the minimization of of the total energy needs to achieve energy savings. As for the existing buildings, they should be renovated so that maximum energy savings is achieved. On the other hand, the EU’s target for 2020 is that new buildings must be of zero carbon dioxide emissions. For the implementation of this goal, buildings should be designed according to the principles of bioclimatic architecture to minimize energy needs, but also systems of Renewable Energy Sources should be applied to produce thermal energy and electricity, in order to minimize carbon dioxide emissions from fossil fuels. In the present thesis, strategies aiming to harmonic integration of buildings in the natural environment are developed, holistic energy saving aspects for buildings are presented, aspects regarding the next step to the target for 2020 are given, and some new designs of building integrated RES, investigated at the Solar Energy Laboratory, are suggested. Approaching the holistic contribution of the renewable energy sources (RES) to buildings for total cover of their energy demand, and the achievement of nearly zero energy buildings, the contribution of photovoltaics in disadvantageous inclination and azimuth angle is experimentally studied. The contribution of diffuse reflectors to pV’s energy efficiency, the impact of thermal insulation materials and the impact of limitating the thermal losses to PV’s operation, are studied as well. Furthermore, the use of every single part of the building in order to contribute to its energy supply, is considered. Designs for photovoltaic integration on horizontal and inclined roofs and facades are suggested, combined with booster reflector if possible, aiming to achieve zero energy balance of buildings.