This doctoral thesis proposes a new method of energy retrofitting of existing residential buildings towards nearly zero-energy status. The topic of energy retrofitting of existing buildings is widely discussed and lamented within the European Union and the Member states and is enshrined in the Directive 2010/31/EU. This research is in line with the European Union strategy Europe 2020 which sets targets for climate change and energy sustainability. The thesis describes the study of building energy performance of a pilot energy retrofitted residential building towards nearly zero-energy where progressive design technologies, such as energy modelling, monitoring, building optimisation and verification were used. This case study helped to formulate the recommendations on the effectiveness of various passive and active design methods together with renewable energy systems and after the extensive research it contributes to model and verify the future expectation and energy efficiency requirements of the residential market.

Without decarbonizing cities energy and climate objectives cannot be achieved as cities account for approximately two thirds of energy consumption and emissions. This goal of decarbonizing cities has to be facilitated by promoting net-zero/positive energy buildings and districts and replicating them, driving cities towards sustainability goals. Many projects in smart cities demonstrate novel and groundbreaking low-carbon solutions in demonstration and lighthouse projects. However, as the historical, geographic, political, social and economic context of urban areas vary greatly, it is not always easy to repeat the solution in another city or even district. It is therefore important to look for the opportunities to scale up or repeat successful pilots. The purpose of this paper is to explore common trends in technologies and replication strategies for positive energy buildings or districts in smart city projects, based on the practical experience from a case study in Leipzig—one of the lighthouse cities in the project SPARCS. One of the key findings the paper has proven is the necessity of a profound replication modelling to deepen the understanding of upscaling processes. Three models analyzed in this article are able to provide a multidimensional representation of the solution to be replicated.

Objectives set by the EU means that all buildings after 2020 has to be nearly zero energy buildings. This means that thicker layers of insulation have to be added in the wall construction which makes the wall thicker. It means that the living area will be reduced. Vacuum insulation is a highly effective type of insulation and because of its low thermal conductivity it has the ability to reduce the thickness in wall structures. This project investigates a proposal to apply vacuum insulation in one-storey buildings. In order to achieve the goals of the project, a proposal for a one-storey building was developed. Calculations have been made and the proposal was developed as an alternative to show how to construct a family home containing vacuum insulation. The empirical data was collected through interviews, document analysis and literature studies. The collected data was analyzed together with the theoretical framework that has been developed through literature studies and document analysis. Creating a wall construction containing vacuum insulation as a primary insulation usually means that the wall will be considerably thinner than a wall construction with traditional insulation. This means that living area can be saved. Vacuum insulation has to be protected properly as it is easily punctured where upon it loses the most of its insulation capacity. Vacuum insulation is not common on the Swedish construction market today, this is due to many factors, including its high price. Vacuum insulation is a good problem solver which can be used in bay windows to gain extra space. One can also make use for it in tight spaces. From an economic point of view vacuum insulation offers the greatest advantages in cities where living space is considerably higher than in rural areas. To take part of the work there is no need for prior knowledge about vacuum insulation. The project focuses only on wall structures in the single-storey villas, therefor, no indentations has been made on the floor- and roof structures or other building types. The project only focuses on newly constructed buildings. No calculations are made for moisture or production costs. / Mål uppsatta av EU innebär att samtliga byggnader som uppförs vid år 2020 måste vara nära-nollenergihus. För väggarna i konstruktionen innebär det att tjockare lager av isolering måste adderas vilket ger bredare väggkonstruktioner. Bredare väggkonstruktioner innebär även att boarean minskas. Vakuumisolering är ett högeffektivt isoleringsmaterial som genom sin låga värmeledningsförmåga har möjligheten att minska tjockleken vid väggkonstruktioner på grund av dess tunna skikt. Arbetet utreder ett förslag att applicera vakuumisolering i enplansvillor. För att uppnå arbetets mål har ett förslag på enplansvilla tagits fram. Beräkningar har gjorts och förslaget är framtaget som ett alternativ för att visa hur en villa innehållande vakuumisolering kan utformas. Det empiriska materialet har samlats in genom intervjuer, dokumentanalyser samt litteraturstudier. Empirin analyseras sedan tillsammans med det framtagna teoretiska ramverket genom litteraturstudier och dokumentanalyser. Att skapa en väggkonstruktion med vakuumisolering som primär isolering betyder oftast att väggen blir avsevärt mycket tunnare än en väggkonstruktion av traditionell isolering, vilket betyder att boarea kan sparas. Vakuumisolering måste skyddas på rätt sätt i väggkonstruktioner eftersom materialet lätt punkteras varpå det förlorar den största delen av sin isoleringsförmåga. Idag är inte vakuumisolering utbrett på den svenska byggmarknaden vilket beror på många faktorer, bland annat dess höga pris. Vakuumisolering är en väldigt bra problemlösare som med fördel kan användas i burspråk för att vinna extra utrymme. Det kan även användas i trånga utrymmen som elnischar. Ur ekonomisk synpunkt ger vakuumisolering störst fördel i städer där boarea per kvadratmeter är högre än motsvarande på landsbygden. För att ta del av arbetet krävs inga förkunskaper om vakuumisolering. Arbetet fokuserar endast på väggkonstruktioner i enplansvillor, därför har inga fördjupningar skett på golv- och takkonstruktioner eller andra byggnadstyper. Enbart nybyggnationer av trästommar är utrett. Beräkningar är inte gjorda för fukt och produktionskostnader.

This thesis investigated application of the heat recovery ventilation using an exhaust air heat pump and a roof top photovoltaic (PV) system for a group of three multi-family houses located in Ludvika, Sunnansjö. The buildings in the existing condition have mechanical ventilation and a centralized heating system consists of a pellet boiler as the main source and an oil boiler as back up. Exhaust air heat pump (EAHP) has been known by the previous relevant researches as an effective solution to promote the energy efficiency in the buildings. Furthermore, reduction in PV cost has made the PV as a financially viable option to be contributed in supplying electricity demand. In this respect, this thesis aimed to calculate the potential of energy saving in the case study using the combination of EAHP and PV. For this purpose, the buildings and the proposed energy system were simulated to enable the comparison of energy demand before and after the renovation. The simulation was gradually progressed through several phases and each stage created the prerequisites of the next. Since the buildings were relatively similar in terms of boundary conditions, one of the buildings were initially modeled and the concluded space heating (SH) demand was extrapolated to the three buildings scope. The simulation of the building was done using 3dimensional thermal model offered by Trnsys3d. The primary results were also calibrated against the available annual fuel consumption data. In the second phase, a pre-developed TRNSYS model of the energy system was completed using the result of previous step as the total SH demand as well as the estimated domestic hot water (DHW) consumption from a stochastic model. This simulation produced the electricity demand profile of the heat pump when the heat pump provided the total heat demand. Subsequently, the electricity consumption of the flats and operational equipment were estimated using stochastic model and available monthly measurement, respectively. Since the feasibility and optimal placement of 74 𝑘𝑊 PV modules offered for these buildings had been already examined by the author in another study, the final simulation were performed in an hourly basis considering PV production and total electricity demand; i.e. EAHP, flats consumption and operational equipment. The results of the simulation showed that 21 % of total electricity demand during a year could be supplied by the proposed PV system even without any electrical storage, whereas 74 % of total yearly PV production is consumed by the local loads. The results also proved that removing old inefficient oil boiler and supplementing the pellet boiler with the combination of EAHP and PV could mitigate the annual purchased energy (including electricity and pellet) by approximately 40 % compared to the current condition.

Purpose: This degree project aims to see how the energy demand from active heating of detached houses can be improved to meet the energy performance requirements set for nearly zero-energy buildings by Boverket (The Swedish National Board of Housing, Building and Planning). Method: To accomplish this, the benefits from two different energy-saving installations are studied: bedrock heat pumps and heat exchangers in Heat Recovery Ventilation Systems (HRV-systems). These are then compared in a new and an older detached house with very different heat losses. There are several reports of energy-saving systems in detached houses. What distinguishes this work is that it compares the specific results from the added energy-saving system depending on whether it was added first or last. The older detached house is an important part of this work as it represents a possible impact on parts of the existing housing stock with a similar technical standard. The energy balance for the buildings is calculated monthly with all contributions from passive heat considered, and with the energy demand for active heating as the main result. Results: It is very difficult to meet the energy performance requirements for an older detached house without extensive measures or renovations. The HRV-system had a low to very low impact. Both types of detached houses have a lot to gain from an investment in bedrock heating, especially the older one that has high energy demands. However, the new detached house with a higher technical standard in the building envelope, was the only one to meet the energy requirements with the bedrock heat pump on its own. Conclusion: Bedrock heating can be a very profitable investment as it provides heat both for the active heating of the building as well as for the domestic hot water. In order to meet tougher energy requirements, the bedrock heat pump may need to be accompanied by an improved and more energy-efficient building envelope and the supply of self-produced electricity, such as solar cells. HRV-systems require a good air tightness and an energy-efficient building envelope to be profitable. In older detached houses, it is not a profitable investment, as it does not have sufficiently large proportions of controlled ventilation to work with. In newer houses the proportion of controlled ventilation is bigger, but the amount of heat loss that can be affected is still not as big as the energy savings a bedrock heat pump can bring.

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.

The thesis deals with the issue will be nearly zero energy. The theoretical part is divided into several chapters. Describes the requirements of applicable legislation of the Czech Republic and the EU and the application of renewable energy in these buildings. The third and last part serves as a basis for part of the experiment. Calculation section applies theoretical knowledge into practice. The subject has become a new residential building in which they are designed to ensure the technical equipment required internal environment. The proposal concerns the heating, ventilation, cooling, domestic hot water and lighting. At the end are attached graphic of energy performance certificates (PENB) and evaluated the economic and ecological point of view. The experiment deals with the measurement of the internal microclimate administrative building type in Brno, with regard to the requirements of current legislation of the Czech Republic.

The theoretical part deals at the beginning with wooden buildings and suitable materials. Then information about low energy houses, passive houses and requirements for new buildings is introduced. The theoretical part of the work also summarizes the selection of the technological solution. Important part is about individual life cycle stages of the building, wear and tear of the buildings and whole life costs of the building that the investor is interested in. Practical part of the thesis consists of a case study of the wooden family house where the whole life costs of the building life cycle are solved.