The present thesis has been carried out during the spring of 2017 on behalf of Gavlegårdarna AB. This is a public housing company in Gävle (Sweden) which is a large energy consumer, over 200 million SEK per year, and has the ambitious goal of reduce its energy consumption by 20 % between 2009 and 2020. Many multi-family apartment blocks were built during the "million programme" in the 60’s and 70’s when thermal comfort was the priority and not the energy saving. Nevertheless, this perspective has changed and old buildings from that time have been retrofitted lately, but there are many left still. In fact, one of these buildings will be retrofitted in the near future so a valid model is needed to study the energy saving measures to be taken. The aim of this thesis is to get through a calibration process to obtain a reliable and valid model in the building simulation program IDA ICE 4.7.1. Once this has been achieved it will be possible to carry out the building’s energy performance assessment. IDA ICE has shown some limitations in terms of thermal bridges which has accounted for almost 15 % of total transmission heat losses. For this reason, it is important to make a detailed evaluation of certain joints between elements for which heat losses are abundant. COMSOL Multiphysics® finite element software has been used to calculate these transmittances and then use them as input to IDA ICE to carry out the simulation. Through an evidence-based methodology, although with some sources of uncertainty, such as, occupants’ behaviour and air infiltration, a valid model has been obtained getting almost the same energy use for space heating than actual consumption with an error of 4% (Once the standard value of 4 kWh/m2 for the estimation of energy use in apartments' airing has been added). The following two values have been introduced to IDA ICE: household electricity and the energy required for heating the measured volume of tap water from 5 °C to 55 °C. Assuming a 16 % of heat losses in the domestic hot water circuit, which means that part of the heat coming from hot water heats up the building. This results in a lower energy supply for heating than the demanded value from IDA ICE. Main heat losses have been through transmission and infiltration or openings. Windows account 11.4 % of the building's envelope, thus the losses through the windows has supposed more than 50 % of the total transmission losses. Regarding thermal comfort, the simulation shows an average Predicted Percentage of Dissatisfied (PPD) of 12 % in the worst apartment. However, the actual value could be considerably lower since the act of airing the apartments has not been taken into account in the simulation as well as the strong sun's irradiation in summer which can be avoided by windows shading. So, it could be considered an acceptable level of discomfort. To meet the National Board of Housing Building and Planning, (Boverket) requirements for new or rehabilitated buildings, several measures should be taken to improve the average thermal transmittance and reduce the specific energy use. Among the energy saving measures it might be interesting replace the windows to 3 pane glazing, improve the ventilation system to heat recovery unit, seal the joints and intersections where thermal bridges might be or add more insulation in the building’s envelope.

Abstract The buildings included in Sweden's old building stock rarely meet the requirements of authorities regarding the indoor environment or energy consumption. Since they are often designed with self-draught ventilation, the cost of switching to mechanical ventilation is high. The windows in the building receives poorer values in terms of u- values, g-values, etc. than produced windows do today, which negatively affects the thermal comfort of people staying in the indoor environment. This case study examines the thermal comfort of two hotel rooms at Elite Grand Hotel since guests experience the hotel rooms in a southerly direction as warm during the summertime. This is due to the direct solar radiation that affects the thermal comfort in negative term. By simulating the building in IDA ICE and comparing hotel rooms with the same design and location on its windows, a room with existing properties is examined with respect to the window and a room where the characteristics of the window have been modified with the window film 3M Prestige 70. According to the manufacturer, this window foil is to reduce the heat from the solar radiation, which can lead to a better thermal comfort for hotel guests. The results of the simulations showed that the 3M Prestige 70 window foil reduced the heat from the solar radiation while improving the thermal comfort of the hotel room. Even during the warmest simulated days, the room is perceived as neutral/just right for an applied window foil when it without foil is perceived as warm. After comparing the installation of window foil and window change, it separated about 716 000 SEK for one floor to the advantage of the window foil. Key words: Thermal comfort, IDA-ICE, window foil, simulations.

The European Union (EU) has expressed determination of reducing its energy consumption and the EU’s 2010 Energy Performance of Buildings Directive states that all new buildings must be nearly zero energy by the end of the year 2020. Dynamic or “smart” windows have been shown to be able to reduce HVAC energy consumption, lighting energy and peek cooling loads in hot climates in the US but it is difficult to find any work concerned with colder climates. This study is intended to capture the performance of dynamic windows in a variety of European climates to explore potential contributions to reaching the EU’s energy goals. The building energy simulations of this study have been conducted in IDA ICE for an office section with a large window. Three model variants are compared: without a window shading, with an external window blind and with a dynamic window. This comparison is repeated for six different locations; Kiruna, Reykjavik, Stockholm, Copenhagen, Paris and Madrid. The results of this study show that the dynamic window can reduce the total consumed energy for lighting, heating and cooling in the range of 10%-30% more than the external blind, depending on location. The reduction is 50%-75% when compared to the unshaded window. This level of performance can move Europe a step closer to zero energy buildings.

In 2013, Stockholms Hamnar began a development project for Värtahamnen, one of Stockholms most important harbors, and also decided to build a new ferry terminal that is better suited to meet the increasing capacity demand. The new terminal will feature a borehole storage that will be used to cover the building’s heating and cooling demands. The boreholes have already been drilled and currently the construction of the building is being planned. The overall objective of this project is to study the new terminal and its borehole storage regarding certain input parameters (such as internal heat gains and the U-value of windows) that affect the building’s annual heating and cooling demands, as well as long-term temperature of the borehole storage. To do this, two modeling programs are used: IDA ICE and EED (Earth Energy Designer). The project focuses on three main parts. Part one is a sensitivity analysis of internal loads and construction specific parameters that shows how a variation in these affects the heating and cooling demands. To accomplish this, several models are created and simulated in IDA ICE. In part two, the long-term ground temperature is studied for two of the models analyzed in part one. This is done in both IDA (through a new borehole module) and EED, followed by a comparison of these results. The last part presents the possible amount of free cooling that can be taken from the ground. This estimation is made through simulations in EED, using altered load profiles of the two previously mentioned models. Additionally, this part covers the effects of a changed borehole configuration (number of boreholes, depth, layout, etc.). The results of the first part (the sensitivity analysis) show that there is a rather large variation in annual heating and cooling demands depending on what approach is used for estimating a reasonable amount of internal loads. One way to do this is to first determine the maximum possible load in each zone and then, when simulating the annual energy demand, reduce the total load in the whole building by a certain factor. Another approach is to, from the start of the building modeling, more accurately try to estimate the average amount of internal loads in each zone. In the second part, due to unbalanced load profiles for both analyzed models, the temperature of the borehole storage will increase over time if there is no limitation of the amount of cooling taken from the ground. The results of IDA generally agree with those of EED. In the last part of the project it is shown that a thermally more favorable borehole installation could increase the relative amount of free cooling from the ground, compared to the current installation.

According to a decision of the European Commission, measures are to be taken to reduce the use of energy in the EU. The goal is to reduce it by 20 % compared to the current use. This shall be done to the year 2020 (European Commission, 2011). One industry that use large amounts of energy is the construction of buildings which account for almost a third of the energy use (Brogren, 2012). The major part of the energy that is used in the construction industry is not used when the buildings are built, but rather during the rest of their subsequent lifetime. There is a great potential to save energy by reducing the energy that is used to maintain a satisfactory indoor climate. Recovery of excess heat and excess cold is a solution that the European Commission think has the biggest potential to reduce the total energy consumption. The most common system used for energy recovery is air to air heat exchangers connected with the supply air and the exhaust air. For different reasons it is not possible to use this kind of system in several buildings. If that is the case there is a possibility to use a liquid coupled recovery system instead. If an additional source of excess heat or excess cooling exist within the building, or nearby, it is also possible to connect this to the system which would increase the ability to save energy even more. The purpose of this thesis has been to develop a tool for energy calculations in liquid-coupled recovery systems. This tool has been developed in the program IDA ICE (used for energy calculations) and has made it possible to perform dynamic simulations in this kind of system over the timeframe of a whole year and with a very short calculation time. The tool is flexible in terms of its components and system design so it can be used for several different types of projects. Everything from simple systems with fixed brine flow with only one supply air and exhaust air unit to systems with several units, various types of control possibilities and an addition of excess heat from, for example, a room containing computer servers. The tool that has been developed has been verified and used to calculate the potential to save energy in a system that is installed at the Ångström laboratory in Uppsala. The tool has shown that with the kind of control and the conditions that currently exist at the laboratory the energy consumption could be reduced by 444 MWh which in this case almost is 50 % of the current energy consumption. Besides the recovery system in Ångström two more systems have been investigated, a server room for The Royal Institute of Technology and the server halls that Facebook is building near Luleå town. The investigation shows that there exist very large amounts of heat that is possible to recover in buildings that include server rooms and that the installed recovery systems, if there are any, in many cases could be improved. Besides constructing recovery systems that recover heat or cold in buildings it is also possible to build this kind of system that recover heat or cold between buildings in the same area. The tool can also be used to investigate how such a system should work in order to minimize the use of energy as much as possible. A solution where heat and cold is recovered between multiple buildings is a solution that probably will be very interesting in the future, which means that this tool could come in handy.

Idén om att kunna utnyttja ett växthus till att skapa ett lokalt mikroklimat kring en byggnad är inte ny, redan 1976 byggdes en sådan villa ute i Saltsjöbaden utanför Stockholm. Där byggdes ett hus inuti ett växthus, och det finns även andra exempel från Sverige och utlandet. Det är däremot ingen vidare utbredd byggnadslösning utan det är endast ett fåtal byggnader som är byggda enligt den principen. Tanken är att glasbyggnaden som omsluter den inre byggnaden ska ge varmare temperaturer runt huset och därmed minska byggnadens värmebehov.  I detta examensarbete har en byggnad innesluten i en glasbyggnad simulerats i simuleringsprogrammet IDA ICE 4.21. Modellen ska gestalta principen och är inte baserad på en existerande byggnad. Byggnaden har antagits ha kontorsverksamhet och vara placerad i Stockholm. Glasbyggnaden har ingen mekanisk ventilation och ingen tillförsel av värme eller kyla görs. Vid övertemperaturer i mikroklimatet öppnas vädringsluckor. Resultatet visade att för en byggnad av nybyggnadsstandard kan 30 % av värmebehovet reduceras, något som ledde till en minskning med 10,6 % av driftenergin och en minskning med 6,0 % av den totala energianvändningen för byggnaden. På en mindre isolerad byggnad blev effekten större, värmebehovet minskade 41,1 %, driftenergin minskade med 30,8 % och den totala energianvändningen minskade med 22,9 %. Då fönstren i innerbyggnaden har låga g-värden ökade kylbehovet när mikroklimatet lades till, men för en byggnad med mindre isolering och med fönster med högre g-värde minskade även kylbehovet när mikroklimatet lades till. Mikroklimatet gör att medeltemperaturen per månad ökar utanför innerbyggnadens klimatskal. Ökningen hos temperaturen blir större ju fler soltimmar månaden har. Månader med i princip ingen sol alls har mikroklimatet endast marginellt högre temperatur. Under ett dygn varierar temperaturerna betydligt mer med mikroklimatet. Nattetid eller vid andra tillfällen då solen inte är framme är temperaturen endast någon grad över utomhustemperaturen, men då solen är framme kan skillnaderna bli 10 °C ‑ 15 °C mellan mikroklimatets temperatur och utomhustemperaturen. Temperaturstyrning med olika gränsvärden under sommaren jämfört med övriga året möjliggör bättre utnyttjande av mikroklimatets möjligheter att spara energi. / The idea of profiting from a greenhouse to create a local microclimate around a building is not new, in 1976 such a house was built in Saltsjöbaden outside of Stockholm. The house was built inside a greenhouse, and there are also other examples from both Sweden and abroad. However, this is not a widely spread building solution, and there are only a few buildings that are built in Sweden according to this principle. The idea is that a glass building that encloses an internal building will provide warmer temperatures around the house and as a result the building's heating demand could be reduced.  In this thesis a building enclosed in a glass building was simulated in the simulation program IDA ICE 4.21. The model should prove principle and is thus not based on an existing building. The building has been assumed to be an office building that is based in Stockholm. The glass building has no mechanical ventilation, and no supply of heating or cooling. Airing hatches are opened when the temperatures in the microclimate reaches temperatures above the comfort level. The results showed that for a building of new built standard, 30 % of the heating demand is reduced, which led to a decrease of 10.6 % of facility energy and a decrease of 6.0 % of the total energy use for the building. On a less insulated building the effect was greater, the heating demand decreased 41.1 %, facility energy decreased by 30.8 % and the total energy use was reduced by 22.9 %. When the windows in the enclosed building have low g-values, as in the case for the building of new built standard, the cooling demand increased with the usage of a microclimate. With the case of windows having a higher g-value, like the less insulated building, even the cooling demand decreased as the microclimate was added. A microclimate makes the average temperature per month increase outside the internal building envelope. The increase is larger when the number of hours with sun is higher. During months with virtually no sun at all, the microclimate has only marginally higher temperature than the outside temperature. During a day the temperatures vary much more inside the microclimate, than outside. At night or at other times when there is no sunshine, the temperature is only a few degrees above the outside temperature, but when the sun is out, the differences may be 10 °C – 15 °C between the temperature in the microclimate and the outdoor temperature. The use of various set points for the temperature controlled airing hatches during the summer compared to the rest of the year allows for better utilization of the microclimates potential for saving energy.

The increasing attention towards energy efficiency issues has triggered an important process involving the renovation of existing buildings and, at the same time, the creation of recognized certifications assuring the quality of the projects. In line with this trend, the Sweco headquarters, an office building characterized by 24700 m2 of floor area and located in Stockholm, was totally retrofitted in 2012 and obtained the Gold rating after being assessed with the Miljöbyggnad certification procedure. The HVAC system was a key element of the retrofit project since one of the final aims was to combine high indoor environment standards with efficient system performances. However, even if the quality of the design is certified, it is possible that, under real operating conditions, complex systems behave differently from the expectations and adjustments are necessary to correct the emerged gap. To achieve this goal, it is essential to identify the points of weakness of the system by carrying out an energy performance analysis, which is the core of this project. In fact, after providing an overview of the building and the retrofit, this work focuses on the analysis of the cooling system installed in the Sweco building and proves the importance of adopting a step-by-step approach to the problem. Therefore, an increasing level of detail characterizes each step of the analysis, whose final aim is to highlight potential aspects to be improved and create a baseline to test possible solutions. / SIRen

Baserat på den höga energianvändningen inom bostads- och servicesektorn i Sverige idag där det sätts upp mål om att minska energianvändnigen och effektivisera processer inom denna sektor, har detta projekt handlat om att komma med åtgärdsförslag för en mins- ka energianvändning av en befintlig lokalbyggnad i Uppsala. Med hjälp av IDA ICE har det gjorts effekt- och energisimuleringar av denna byggnad för att se om det går att sänka effekt- och energibehovet så pass mycket att byggnaden skulle kunna klara sig på endast ett av de två uppvärmningssystem som finns idag. De åtgärder som görs i detta arbete är tilläggsisolering i yttervägg och byte av befintliga FTX-system, ytterligare görs en analys på den optimala tjockleken av isolering utifrån ett ekonomiskt perspektiv. Resultatet i denna rapport visar att det är möjligt för fastigheten att endast klara sig på ett uppvärmningssy- stem med kombination av de två åtgärderna. Den ekonomiskt optimala isoleringstjockleken visades vara 125 mm och kan ge en energibesparing på 25% och ekonomisk besparing på 107 345 kr/år. Vid kombination av de två åtgärderna kan en energibesparing på 40% göras och en ekonomisk besparing på 100 443 kr/år. / Based on the high energy use in the housing and service sector in Sweden today, where goals are set to reduce energy use and streamline energy processes in this sector, this project has been about coming up with measures to reduce energy use of an existing local building in Uppsala. With the help of IDA ICE, heating load and energy simulations have been made for this building to see if it is possible to reduce the heating load and energy needs so much that the building could manage on only one of the two heating systems that exist today. The measures taken in this work are additional insulation in the outer wall and replacement of existing ventilation systems, a further analysis is made of the optimal thickness of insulation from an economic perspective. The results of this report show that it is possible for the property to manage only on a heating system with a combination of the two measures. The economically optimal insulation thickness was shown to be 125 mm and can provide an energy saving of 25% and an economic saving of 107 345 kr/year. By combining the two measures, an energy saving of 40% can be made and a financial saving of 100 443 kr/year.

Detta examensarbete analyserar optimering av energibesparande åtgärder vid ombyggnad. Stor del av de ca en miljon byggda bostäderna uppförda mellan åren 1950-1975 står idag inför ett stort renoveringsbehov. Samtidigt måste husen energieffektiviseras, då de står för en stor del av landets energianvändning. Det finns stora energibesparingsmöjligheter i och med energieffektiviseringen utav husen, om de mest optimala valen utförs. Samtidigt är det viktigt att visa på att de valda åtgärderna är ekonomiskt hållbara, för att initiativ till att energieffektivisera ska tas. Optimeringen utförs med hjälp av en koppling mellan ett simulationsprogram och ett optimeringsprogram. Målet är att visa fördelarna med den undersökta metoden och vilka resultat som erhålls. Energieffektivisering av en byggnad kan vara en komplex uppgift med många aspekter att ta hänsyn till. Det kan vara svårt att veta hur olika åtgärder påverkar energiprestandan och hur de samspelar med varandra. Det är dessutom alldeles för tidskrävande att manuellt undersöka olika värden på alla åtgärder, speciellt när åtgärderna är många. Metoden har testats på ett aktuellt ombyggnadsprojekt i förorten Kista, norr om Stockholm. Det studerade radhusområdet är byggt under den senare delen av miljonprogramssåren. Energideklaration på området visar att husen har en genomsnittlig energiprestanda på 182 kWh/m2 år, vilket kan jämföras med dagens nybyggnadskrav på 110 kWh/m2år. De energibesparande åtgärderna ska optimeras så att den lägsta livscykelkostnaden, under en vald tidsperiod, erhålls. En viktig aspekt i arbetet har varit att priserna ska vara dagsfärska och hämtade direkt ur det studerade projektet. Det har varit viktigt för att påvisa att metoden kan implementeras på verkliga projekt och att varje projekt är unikt. Resultaten presenteras i form av tre olika scenarier. Scenarierna skiljer sig genom att priser och parametrar som berör den ekonomiska kalkylen modifieras. Optimeringsresultaten indikerar på att energibehovet kan reduceras med upp till 60 %, i jämförelse med ursprungligt skick, samtidigt som god lönsamhet uppnås. Den presenterade metoden visade sig vara ett kraftfullt verktyg som är ett bra komplement i projekterings fasen. Metoden kan säkerligen vidareutvecklas för att blir mer användarvänligt och lättförståeligt.

The energy consumption rate of non-OECD countries rises about 2.3 percent per year as compared to the energy consumption rate of OECD countries which is 0.6 percent. If developing countries use energy efficient technology and integrate renewable energy systems in the new building their carbon dioxide emission rate reduces by 25 to 44 percent.  However, even now, renewable energy integrated buildings are hardly considered while constructing them.   This thesis work focuses on the study of solar cooling system options for residential house in Bahir Dar city. To meet the demand of housing in the city, different type of apartments and villa houses are under construction.  Case study was made focusing on two types of residential houses (condominium apartment and Impact Real-estate Villa house) to determine the cooling load and to select cooling system.   Simulation results of IDA ICE software show that the average operative temperatures and cooling loads for condominium apartment and Real-estate Vila are 31.8oC and 30.7oC, 5.53 kW and 5.73 kW respectively. Most of the residences are not satisfied at this operating temperature.   There are different types of solar cooling systems.  Solar Sorption cooling systems are commonly used which can also be classified in to absorption, adsorption and desiccant cooling systems.  Solar adsorption cooling systems are easy to manufacture locally as compared to solar absorption cooling systems. They do not have moving parts. Some of the working medium pairs used in adsorption cooling system are: Activated Carbon/Ammonia, Silica gel/ water, Zeolite/water. Adsorption chillier with Silica gel/ water as a working pair was selected since it can operate at regeneration/desorption temperature as low as 45oC coming from flat plate collectors.  At 75oC regeneration temperature, the system delivers 9oC chilled water temperature.   The selected solar adsorption chiller has been compared with kerosene based adsorption cooling system using HOMER software.  In this project, the optimization was limited on cost comparison between the two energy sources.  The solar based cooling system has lower working cost.   From cooling load simulation result direct solar irradiation is the highest source of cooling load for both houses. This gives an opportunity for passive solar cooling technology.