The building sector is one of the sectors with the highest energy utilization and is one of the largest sources of CO2 emissions worldwide. At the same time, energy prices in Europe have significantly increased in recent years. For these two reasons, energy efficiency in buildings has become highly relevant for public and private organizations aiming to reduce energy consumption for the operation of buildings and therebyd ecrease their carbon footprint and operation costs for users and owners. This master’s thesis aims to identify areas of opportunity for energy utilization reduction and the implementation of energy efficiency strategies in four buildings of the KTH Campus, owned by Akademiska Hus. First, an energy data analysis of the last years of the operation of the buildings was conducted to identify trends and atypical energy uses. Next, energy audits were performed on the most important energy-consuming equipment and major building facilities to understand the operation conditions and characteristics of electrical, heating, and cooling systems, aiming to identify areas of opportunity for reducing energy use from current operation of the buildings. Subsequently, after understanding the energy use in the four buildings, models of the buildings were created in IDA ICE. The approach involved two steps: first, modeling the buildings’ geometry and adapting their energy consumption to match the patterns identified in the previous data analysis; and secondly, modeling the implementation of energy efficiency strategies on the buildings that aim to improve the findings of the data analysis and energy audits performed previously. These energy efficient models were subjected to energy performance analysis, economic analysis, investment feasibility analysis, among others. The results obtained from the models with energy efficiency strategies showed energy and economic savings that varied from building to building through the automation of lighting systems in the buildings, with an average return on investment of 2.5 years. Likewise, significant savings were achieved by reducing the heating setpoint during nights, causing the district heating usage to differ from the daytime demand, resulting in savings between 5 % and 8 % of the total annual energy use in the buildings, without any required investment. Additionally, the implementation of renewable energy solutions was studied by modeling the use of solar panels in the buildings, leading to a reduction in electrical grid demand between 20 % and 48 %, depending on the available area for the panels, with an average return on investment of 5.5 years. Other strategies were also studied and discussed in this report. In conclusion, this study provides evidence of the energy, economic, and environmental feasibility of different energy efficiency strategies that can be implemented in the buildings of the KTH campus. These strategies contribute to achieving the environmental objectives of Akademiska Hus and KTH. / Byggnadssektorn är en av de sektorer som har högst energianvändning och är en av de största källorna till utsläpp globalt. Samtidigt har energipriserna i Europa ökat avsevärt de senaste åren. Av dessa två skäl har energieffektivitet i byggnader blivit mycket relevant för offentliga och privata organisationer som strävar efter att minska energiförbrukningen för byggnaders drift och därigenom minska deras koldioxidavtryck och driftskostnader för användare och ägare. Denna master avhandlingsyftar till att identifiera möjlighetsområden för minskning av energianvändning samt implementering av energieffektivitetsstrategier i fyra byggnader på KTH Campus, ägda av Akademiska Hus. Först genomfördes en analys av energidata från de senaste åren av byggnadernas drift för att identifiera trender och otypisk energianvändning. Därefter utfördes energirevisioner av de mest betydande energiförbrukande utrustningarna och huvudsakliga byggnadsanläggningarna för att förstå driftsförhållandena och egenskaperna hos elektriska, uppvärmnings- och kylsystem. Syftet var att identifiera möjlighetsområden för att minska energianvändningen från nuvarande drift av byggnaderna. Efter att ha förstått energianvändningen i de fyra byggnaderna skapades modeller av byggnaderna i IDA ICE. Tillvägagångssättet innefattade två steg: först att modellera byggnadernas geometri och anpassa deras energiförbrukning för att matcha de mönster som identifierades i den tidigare dataanalysen. Sedan modellering av implementeringen av energieffektivitetsstrategier på byggnaderna, som syftar till att förbättra resultaten av den tidigare utförda dataanalysen och energirevisionerna. Dessa energieffektiva modeller underkastades analys av energiprestanda, ekonomisk analys, investeringsmöjlighetsanalys, bland andra. Resultaten som erhölls från modellerna med energieffektivitetsstrategier visade på energi- och ekonomiska besparingar som varierade från byggnad till byggnad genom automatisering av belysningssystemen i byggnaderna, med en genomsnittlig avkastning på investeringen på 2.5 år. På samma sätt uppnåddes betydande besparingar genom att sänka uppvärmningsinställningen under nätterna, vilket fick fjärrvärmeförbrukningen att skilja sig från dagtidens efterfrågan och resulterade i besparingar mellan 5 % och 8 % av den totala årliga energianvändningen i byggnaderna, utan någon nödvändig investering. Dessutom studerades implementeringen av förnybara energilösningar genom modellering av användningen av solpaneler i byggnaderna, vilket ledde till en minskning av elnätets efterfrågan med mellan 20 % och 48 %, beroende på tillgänglig yta för panelerna, med en genomsnittlig avkastning på investeringen på 5.5 år. Andra strategier studerades också och diskuterades i denna rapport. Sammanfattningsvis ger denna studie bevis på energi-, ekonomi- och miljömässig genomförbarhet av olika energieffektivitetsstrategier som kan implementeras i byggnaderna på KTH Campus. Dessa strategier bidrar till att uppnå miljömålen för Akademiska Hus och KTH.

Detta examensarbete på 15 hp. har haft målet att kunna hitta en guide för planering av fönster för byggnader som ska certifieras med Miljöbyggnad. I certifieringsprocessen ingår beräkning av solvärmelasten, vilket ger en siffra på hur mycket solvärme som strålar in i byggnaden, som sedan kan behövas ventileras eller kylas bort under sommarhalvåret. I processen beräknas även dagsljusfaktorn, vilket ger en siffra på hur mycket dagsljus kommer in i byggnaden. Då dessa två aspekter påverkar negativt på varandra har olika tester gjorts med hjälp av olika datasimuleringar för att finna vilken fönsterarea skulle kunna vara lämplig för att få ett bra betyg i Miljöbyggnad. Här har även tester gjorts för det termiska klimatet, som är ytterligare en aspekt Miljöbyggnad ser på, och som fönstret kan påverka. För arbetet har en blivande kontorsbyggnad, Svalan i Uppsala, varit som mall för dessa tester. Då det finns väldigt många olika parametrar som behövs för att kunna göra alla simuleringar och uträkningar är det svårt att göra en guide som fungerar för alla projekt. I detta arbete finns två lika stora kontor som har fönster åt olika väderstreck och med olika g-värden, för att se skillnader på dessa har simuleringar gjorts för olika fönsterareor, och olika fönsterplaceringar. För simuleringarna har IDA 4 och Velux Daylight Visualizer använts. Arbetet resulterade i att fönstrets placering i rummet ger stor skillnad på dagljusfaktorn, och även för fönstrets utformning, dock ingen för solvärmelasten. För att påverka solvärmelasten kan glasarean i fönstret ändras, g-värdet, eller golvarean för rummet. När dessa parametrar verkar positivt för solvärmelasten, påverkar de negativt för dagsljusfaktorn, därför måste projektören hitta en bra nivå som fungerar för både solvärmelasten och dagsljusfaktorn. För projektet med två kontor i Svalan gav resultatet att få GULD i både solvärmelast och dagsljusfaktorn fungerar inte utan solavskärmning. Som bäst når den ena GULD och den andra SILVER, vilket kan i slutbetyget ändå räcka för att nå bästa betyget GULD med Miljöbyggnad, så länge de andra indikatorerna som Miljöbyggnad ser på är tillräckligt bra i projektet. / This report of 15 credits has had the goal to find a guide for planning window for buildings to be certified with Miljöbyggnad. The certification process includes calculation of solar heat load, giving a figure of how much sun heat is coming into the building, which may needs to be ventilated or cooled off during the summer. The certification process also demands the daylight factor, which gives a figure of how much natural light enters the building. These two aspects affects each other in a negative way, why various tests have been done using a variety of computer simulations to find what kind of window area would be appropriate to get a good rating in Miljöbyggnad. It has also been tested for the thermal climate, which is another aspect Miljöbyggnad investigates, and that windows can influence. The work uses an upcoming office building, Svalan in Uppsala, as a model for these tests. As there are many different parameters that are needed to make all the simulations and calculations it is difficult to make a guide that works for all projects. In this work there are two equally sized offices that have windows facing different directions and with different g-values, to see the differences in these simulations have been made for various window areas and different window placements. For the simulations, the IDA-ICE 4 and Velux Daylight Visualizer have been used. The work resulted in that the window's placement in the room has a big difference for daylight factor, and also for the window form, however none of the solar load. To affect solar heat load, the glass area of the window can be changed, the g-value, or the floor area of the room. When these parameters seem positive for the solar heat load, are they affecting negatively the daylight factor, therefore the building planner have to find a good level found that works for both solar heat load and the daylight factor. For the project with two offices in Svalan gave the result; to get GOLD in both solar heat load and daylight factor will not work without sun screening. As best reach one of them GOLD and the other SILVER, which can be in the final grade yet sufficient to reach the best grade GOLD with Miljöbyggnad, as long as this projects other Miljöbyggnad factors gives results which is good enough.

Tången 2 is a building situated in Stockholm, Sweden. It´s built in the 1930s and contains both residences and businesses. The property owner, Diligentia AB, wants to lower the energy use in Tången 2. This report consists of an energy audit which clarifies the specific circumstances linked to Tången 2. Collected knowledge is then used, together with the results from the literature study, to decide energy measures to proceed with. Result from the energy audit suggests a high potential to lower the energy use. To calculate the potential energy saving of chosen measures, a model of the building was constructed in IDA ICE. Collected data from the energy audit was used as input in the model. Simulation results suggest that there are several possible measures to implement, both constructional and technical. Results from the economical calculations suggest that there´s a connection between energy saving and investment cost. Even though the energy saving potential of a single measure is significant, it´s not cost effective if it consists of a high investment cost. Results from the study are presented as a program of measures that will lower the energy use and save the owner money in the long run. This study shows that even for a building with big energy saving potential, it´s hard to lower the energy use significantly and maintain a profit. The program of measures suggested in this report has an energy saving potential of 11 % and an IRR of 7, 7 %.

The industrial sector accounts for almost 40 % of the Swedish energy use and in order to meet the EU’s 2020 targets, an efficient production of high quality and great finish goods are more and more in demand. Moreover, it is important to develop the activities with the lowest environmental impact possible.  The energy audit process is an effective tool to achieve it. Thus, in this document the energy audit of an industrial company, Automat Industrier in Gävle, Sweden, was carried out. The energy balance of the building and the potential energy efficiency measures were analyzed with the IDA ICE simulation. The proposed energy retrofitting was apropos of the building envelope, the lighting system, the ventilation system and the installation of a PV system on the roof of the building. The survey indicated that the potential energy savings of the company accounted for 62.5 % of the current electricity use and 48.8 % of the current DH use if all the proposed ameliorations were performed. The main promoter of the electricity savings is the installation of the PV system, with 85 % of influence. Almost 90 % of the DH savings are due to the measures in the ventilation system. Financially, these savings can reach the amounts of 531 597 SEK/year for electricity and 174 201 SEK/year for DH. Nevertheless, the ameliorations regarding the building envelope have very long payback periods. Thus, it was recommended to not pursue them. Fortunately, the energy efficiency measures providing the greatest savings’ payback periods are between 3.47 years and 10.22 years long. As they are independent from each other, the owner has the freedom to decide whether to apply them or not and when if so.

The global share from buildings towards energy usage in residential and commercial buildings have been increasing constantly reaching between 20% to 40% in developed countries and has overtook the other major sectors: industrial and transportation. Energy demand reduction in the building sector is important for Sweden to achieve national energy aims for reduced energy use in the future.  For this reason, energy efficiency measures in buildings today is one of the main objective for energy policy towards 2020 goals.   This project moves on the same path to find energy efficiency potential in Fridhemsskolan buildings in Gävle, Sweden by performing energy audit using IDA-ICE software to simulate energy performance for the buildings under study. In addition, measurements have been made on three of the school buildings named Hus 1, Hus 2 and Hus 3.   The results include different energy efficiency retrofits on each building and economic analysis of these retrofits for each building individually and for the whole buildings together. The presented measures are reducing working hours of the ventilation system in Hus 2, change of CAV system with VAV system in (Hus 1 and Hus 2) and lights changing to LED, s efficient lights and building envelope improvement which includes walls and roof extra insulation and windows replacement.   Replacement of the CAV system in Hus 1 and Hus 2 were not economically beneficial when considering their high cost compared to energy reduction that can be achieved by applying them. On the other hand, energy retrofits analysis showed that combination of the following energy efficiency measures is the most effective and profitable: extra insulation (walls and roof), windows replacement and lights change to LED in the three buildings. In addition to these measure is reducing running hours of the ventilation system in Hus 2.   Implementation of the recommended energy efficiency measures will save 120, 737 kWh/ year of the district heating and 21, 962 kWh/year electricity consumption with capital investment of 417, 396 SEK and 98, 957 SEK/ year cost saving with payback period of 4.2 years. These figures represent 40.3% and 18.1% reduction in district heating and electricity energy use respectively.   Since reducing working hours of ventilation system measure has no capital investment and have the highest figure of energy reduction it reduces payback period significantly. In case the amount of money saved by this measure doesn’t consider; payback period for the other measures which require capital investment will be 13.5 years and the energy saving in terms of cost will be 30, 874 SEK/ year.

Kyrkor som är byggda innan år 1940 skyddas i enlighet med 4 kap. Kyrkliga kulturminnen ur Kulturmiljölagen. Samtidigt efterfrågar kyrkobesökare större krav på inomhusklimatet som för kyrkornas inventarier leder till skador. De två parametrarna temperatur samt relativ fukthalt, och förhållandet mellan dem, utgör därför en viktig del för både bevarandet av kulturhistoriska byggnader och dess inventarier. Vederslövs kyrka är byggd i sten och anses vara en av Kronobergs läns mest välbevarade kyrkor från slutet av 1800-talet. Efter inhämtning av mätvärden från JEFF Electronics styrsystem och utplacerade loggrar i kyrkan har simulering i IDA ICE utförts. Därefter har fyra stycken energieffektiviseringsåtgärder för Vederslövs kyrka presenterats.

Globally, buildings utilize 35 % of the final energy use and contribute to approximately one-third of CO2 emissions. Hence, reducing the energy use of buildings contributes to a large amount of CO2 emissions to be decreased. The building’s energy use is affected by many parameters, including wind which plays an important role in building energy use. In this thesis, we aim to analyze the impact of wind parameters on building’s energy use on two multi-family building types with natural ventilation at various wind sheltering conditions at different climatic zones in Sweden. Building energy simulation models (BES) of a standalone and an attached building located in Visby, Sweden, were constructed with the use of the dynamic BES IDA ICE. Luleå and Malmö were taken as other two study locations to investigate the impact from different climate zones. The simulations were performed with the constructed calculation models, with the various wind sheltering conditions at the different climatic zones to calculate the energy use of the buildings and ventilation and infiltration losses. The sensitivity analysis was then carried out based on changing the wind profile of the climate file to evaluate the impact of wind on the ventilation and infiltration losses, as well as the heat energy use of the building. The results showed that the energy use for space heating of the attached building was 89 kWh/m2 (38 %) lower than the standalone building. The energy use varies between 9–20 kWh/m2 (3–10 %) considering the exposed, semi-exposed and sheltered wind condition for the two building types. In the different climate zones, Luleå has 47 kWh/m2 higher energy use compared to Visby and Malmö for the standalone building. The corresponding figure for the attached building is 25 kWh/m2. The sensitivity analysis show that when the wind speed is increased by 100 %, the ventilation and infiltration losses increase between 3563–18683 kWh (54–61 %) while the energy use of the building increases between 11–54 kWh/m2 (20–27 %).

The importance of energy efficiency in the operation of the built environment is becoming increasingly important. Energy use in the building sector has exceeded both transportation and industry, while within buildings heating, ventilation, and air conditioning has the greatest share. In light of the recent pandemic forcing governments to issue quarantines and stay-at-home orders people are spending even more time indoors, this further emphasizes the importance of proper ventilation and the impacts on energy use. The purpose of this research was to perform a case study of a low environmental impact demonstration house to compare the energy performance of various ventilation strategies. The ventilation strategies varied by overall airflow rate, control strategy, and the presence of heat recovery. Performance was evaluated by establishing a model in IDA ICE, an equation-based modeling tool for the simulation of indoor thermal climate and energy use. The results showed energy savings due to demand-control with a reduction of 12.5%. Results also showed similar savings with a heat recovery system, indicating that any savings in heat loss due to heat recovery is at the expense of increased auxiliary energy. In this particular case, the benefit of upgrading to a heat recovery system from simple demand control set up is not readily apparent. Results also demonstrated trends and possible complications useful to future research plans that aim to measure real world ventilation performance, including how differences in the number and location of sensors impact the efficacy of the demand-controlled systems. A secondary aim was to observe how a newly constructed, low environmental impact home built in Sweden performs according the residential LEED energy budget. The results demonstrated that constructing a house using low impact materials with low embodied energy does not have to negatively impact energy performance, scoring extremely well in the Energy and Atmosphere category of a widely used sustainable building rating system.

In Sweden, there are around 300 000 multi-family buildings with high energy consumption state a high renovation potential in the building sector. This study aims to analyze different renovation measures for a typical theoretical multi-family building to determine their effects on energy consumption, financial profitability, and impacts on obtaining an energy label in the rating system. The reference building was created based on the given energy consumption for the Nils Holgersson building (NH), where the information data accumulated and assessed utilizing dynamic energy simulation software IDA ICE.The selected renovation measures include modifications to the building envelope and ventilation. The reference building was equipped with an exhaust ventilationsystem with no heat recovery. The study showed that heat losses through ventilation contributed to the largest share. The losses through windows and walls are significant; hence selecting ventilated façade and adding insulation were relevant efficiency measures. The study analysis a vacuum insulation panel (VIP) applied for external walls due to its highly efficient thermal properties compared to conventional insulation. The results of life cycle cost analyses (LCCA) for 40 years demonstrated that VIP and ventilated façade have an economic benefit because of the energy cost saving during the operation phase of the building, despite the high initial cost. The cumulative LCC for each measure showed that VIP approaching the conventional insulation within theservice life the ventilated façade is cost-efficient at the end of the 6thyear compared to changing glazing. The selected rating system is Miljöbyggnad (MB). After renovation, the NH building could achieve the bronze level on the energy indicators.The study found that the energy consumption in the base model was 144.7 kWh/m2and the implemented renovation package leads to a reduction of 47 % annual heating demand. As a rule of thumb, the annual energy demand will be 90 kWh/m2, and the cost for the renovation package including installation would be 1150 SEK/m2causing a total energy-saving 2900 SEK/m2at the end of 40 years.

This thesis investigates the possibilities of using hybrid ventilation in an office building in Stockholm. The focus is on simulating the natural airflow to find out for which conditions it is sufficient. The thesis is done at White Arkitekter AB in cooperation and under the supervision of environmental specialists working there. A literature study is carried out to study what has been done before in Sweden as well as in other countries. Computer simulations are used to simulate the airflow to examine the conditions and architecture. A synthetic computer model representing a realistic office building is built up as a starting point. The ventilation method for the natural ventilation part is to take air in through the fa\c{c}ade and use the stack effects in an atrium for natural ventilation. By altering the architecture and the sizes of the openings according to the results from the simulations the building is dimensioned and formed to cope with the rules and requirements about the indoor air quality in workplaces. The simulations are done with a multi zone energy performance simulation tool that can simulate airflows and indoor air climate conditions in the zones as well as the energy consumption. Computational fluid dynamics calculations are then used to more closely simulate the conditions within the zones. The results from those simulations suggest that the natural ventilation as a part of a hybrid ventilation works for all the floors of the building for up to 10$\,^{\circ}\mathrm{C}$. The computational fluid dynamics simulations showed that the thermal comfort of all the occupants is fulfilled for these conditions but there is a risk of occupants experiencing draught because of to high velocities in the air especially for the colder outdoor temperatures. For the higher outdoor temperatures the airflow needs to be enforced to ensure sufficient conditions for the occupants and for the colder temperatures mechanical ventilation is needed to decrease heat losses and avoid the risk of draught.