Despite the great progress made in the energy performance of buildings in recent decades, buildings remain significant energy consumers. Many advanced technologies for increase of energy efficiency have been developed, and strong commitments to increasing the energy performance of buildings have been adopted. The most well-known is the Recast of Energy Performance of Buildings Directive (EPBD), which requires that planners design buildings as nearly zero energy buildings (nZEB), highly energy efficient buildings in which a large share of energy demand is covered by renewable energy sources. In the present article, the evaluation methods and energy performance of advance facade building structures are presented. The structure consists of six-pane multi-layer glass with optional photovoltaic cells integrated in the outer glass layer (BIPV). The method for the determination of the dynamic thermal response model is presented, and the model is validated with experiments. Three indicators were developed (average daily heat flux q̇2 4 at inner surface of the facade structure, the autonomy factor AUT, the and utility factor UTI) to evaluate the all-year energy performance of such advanced building structures according to the heating and cooling energy needs and electricity production. Examples are shown for facade building structures located in three climate regions.

This paper presents research on the nearly Zero Energy Buildings (nZEB) metrics of an all-glass office building with advanced multi-layer six-pane glass and building integrated photovoltaic (BIPV) façade structures in different climate conditions. The study was carried out in the following steps: i) development of a time series model of dynamic thermal response of multi-layer 6-pane glass and BIPV façade structures on the basis of transient computational fluid dynamics simulations, ii) integration of the façade structure dynamic model into the building dynamic model by adapting TRNSYS software code, iii) determination of the final energy balance including heating, cooling, ventilation, lighting, and on-site electricity production, iv) nZEB metrics evaluation considering night-time cooling by ventilation, evaporation cooling and hybrid ventilation of case study office buildings. It is shown that energy need for the cooling of the studied office building is dominant in all considered climate conditions, although it can be decreased up to 23% in most favourable considered climate conditions by implementing free cooling techniques. The case study buildings with BIPV structures on their east and west façades meet more stringed nZEB criteria; in addition, final energy demand decreases by 17-37% in comparison to the reference all-glass building. In the case of all-BIPV buildings, the final energy demand is decreased by 36-48%. Such buildings can significantly contribute to the mitigation of global climate change, as BIPV electricity production exceeds the building's energy demand.Keywords: nearly Zero Energy Buildings, multi-layer glass structures, building integrated photovoltaics, computational fluid dynamics, dynamic building thermal response model, natural space cooling Recently, research has focused on advance multi-layer, vacuum, and aerogel glass façade structures [10-13] with highly reduced U-values for nZEB buildings. However, Murano et al. [14] demonstrated that, with increased window-to-wall ratios, space cooling is the most significant challenge for nZEB in southern European climate conditions. The same conclusions can be derived from the study presented by Bruno, [15]; results also showed that in all-glass buildings yearly energy need is the lowest with glazing with the lowest thermal and total solar energy transmittance. In these studies, static numerical models for glazing prevail, leading to a single thermal transmittance value of glazed façade structures and non-transient heat transfer conditions. Lu and Memari [16] published a study on the evaluation of the thermal transmittance of building envelopes, comparing hot-box laboratory methods for the determination of steady-state thermal transmittance. In their study, they show the importance of using dynamic models in case of in-situ measurement conditions for the accuracy of results. Nevertheless, Foucquier et al. [17] and Li and Wen [18] point out that the transient numerical modelling of the thermal response of the buildings requires the transient mode...

In the past decades, the energy performance of buildings has increased by a factor of 10, which is significantly higher than in other energy use sectors. At that time, the EU's energy and environment policy led to the creation of regulatory requirements, standards and technologies for the implementation of complex systems such as passive buildings or sustainable buildings. European Union expressed commitment to develop sustainable, competitive, secure and decarbonized energy system, by adopting Directive on the Energy Performance of Buildings (EPBD), including requirements for nearly Zero-Energy Buildings (nZEB). Since energy efficiency and environmental sustainability requirements are becoming more and more complex, the knowledge of building designers must be more comprehensive too-from understanding of physical principles, have an overview of legal framework, to be familiar with advanced building service technologies and finally to have a knowledge of using methods for comprehensive verification of the 'final product': nZEB. Awareness that deep interdisciplinary knowledge is the only guarantee that this task will be fulfilled has been a guide to the design of the contents and the scope of this book.Through 14 chapters, the book leads the reader through basics of planning and evaluation of living comfort in the indoor environment, basics of building physics, instructions for determination of thermal response of building structures, explanations and evaluation of nZEB requirements and design, energy efficiency evaluation of buildings' service systems, presentation of methods for planning and evaluation of buildings' energy performance and the environmental impacts caused by lifelong use of energy and materials in buildings. Students of architecture, civil and mechanical engineering and students of other engineering professions, as well as professional building planners, will get acquainted with modern technologies for 'in-situ' and 'near-by' production of heat, cold and electricity in nearly zero-energy buildings including energy-efficient measures and renewable energy technologies utilization. Theoretical content is supported by in-situ experiments results, numerical examples and case studies, which were developed by colleges of Laboratory for Sustainable Technologies in Buildings (LOTZ), Faculty of Mechanical Engineering, University of Ljubljana. v The book is an upgraded teaching material developed in the frame of ERASMUS+ Project EduLabFrame (2014-1-RO01-KA203-002986) and we would like to thank the colleagues involved in the project. The authors would also like to thank Viessmann Werke GmbH & Co. KG for extended picture material. We would like to thank all other cited authors and sources. Finally, we would like to thank company TRIMO d.o.o. to enable TRIMOExpert software for downloading from www.TRIMO/eu.

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