Energy efficiency is an important question to society as well as to individuals and firms. Improving energy efficiency in the building sector is considered an important means to climate mitigation. For real estate owners energy is also a central expenditure item and reducing energy consumption may directly reduce operation costs while at the same time serve as insurance against future energy price increases. Since new buildings only add a few percent annually to the building stock, the potential to reduce total energy consumption primarily lies within the existing building stock. The building stock is ageing and the post-war part of the stock that is in need of renovation is growing. This has been suggested as a window of opportunity to improve energy efficiency, but so far the results have been few. Several factors have been put forward to explain the so called energy efficiency gap – the difference between actual and optimal energy efficiency – one of which is split incentives. What adds to complexity in this case is that distinct differences have been observed in the level of ambition between the real estate companies that have renovated so far. Some companies have undertaken extensive renovation and energy efficiency measures, whereas other companies have done little more than urgent maintenance measures. It seems that real estate owners in general don´t have strong economic incentives to improve energy efficiency in connection to renovation – but what can then explain the differences between strategies? This licentiate thesis examines the incentives among real estate owners to improve energy efficiency, particularly in post-war, multi-family buildings in need of renovation. The purpose is to add knowledge about decisions concerning measures that improve energy efficiency - in terms of incentives, barriers and different motives for real estate owners’ strategies and actions. Results show that real estate owners lack strong economic incentives to invest in energy efficiency in multi-family buildings and the level of investment is dependent on the different motivations, grouped in three levels of ambition, that real estate companies have. One important conclusion is that the heterogeneity between companies that was exposed in the interviews and survey implies that they will not respond similarly to policy stimuli. The heterogeneity should thus be considered when designing policy measures so that public and company resources can be allocated as efficiently as possible, as there are many challenges facing owners of post-war residential buildings. Another conclusion is that from an economic point of view it is important to take the interaction between different measures into account, e.g. between physical measures and measures focusing on changing household behavior. / QC 20110630

The report investigates the feasibility of accessing waste heat at kiln 7 in the Cementa AB cement plant in Slite, Gotland. The background is provided, with a description of the cement manufacturing process. Most of the report concerns itself with the heat transfer capabilities of the plant, therefore a short description of the heat flow within the most essential equipment is provided. The investigation follows a set of steps to derive the conclusion. The first step investigates previous studies to obtain the three most feasible heat sources. The second step investigates the available heat of the selected sources. In the third step, accessing the source is discussed and investigated for both convection and radiation heat transfer methods. It also includes the sizing of the required heat exchangers. Using the new sources, the connection possibilities to existing infrastructure and its benefits are investigated in step four. The connections were made to the existing infrastructure used at kiln 8 for electrical generation and district heating supply. The selections of the most feasible solutions are provided based on heat recovery, payback period and practicality. The final step in the study provides for the final design, which consists of three possible connections or all of them combined. In the conclusion, the final design would provide for a reduction in oil burned, fuel consumption and CO2 emissions and an increase in electricity generated by the existing system. It is recommended that only one of the three connections be installed. / <p>The thesis was conducted at Cementa AB in Slite, Gotland. The supervisor at the plant was Fred Grönwall.</p>

One of the great challenges facing society is to convert theglobal energy system to a sustainable process. Currently, 80%of the world´s energy is supplied through the combustionof fossil fuels. Not only are the fossil resources limited, theutilisation also increases the level of greenhouse gases in theatmosphere. The convertion to a sustainable energy system isproblematic since the technology needed to exploit mostnon-fossil energy sources is not yet fully developed, e.g.solar energy. Biofuel is an available renewable energy sourcewhich is already widely used in many countries. If an effectiveswitch-over from fossil fuels to biofuels is to be realised,biofuels must be viewed as a limited resource. Consequently, itis important that the handling, upgrading and utilisationprocesses involving biofuels are efficient so that itspotential can be fully exploited. This thesis considers efficient biofuel utilisation andupgrading within the sawmill industry. The goal has been toanalyse not only the technical opportunities for energy savingsin the sawmill industry, but also to analyse the costeffectiveness and environmental impact of studied measures. Theheat demand of the sawmill industry is almost completelycovered by its own by-products; primarily bark, sawdust andwood chips. The increased demand and improved economic value ofwoody biofuels on the market is thus an incentive for thesawmill industry to place more focus on energy issues. Thesawmill industry also has a more or less constant heat loadover the year, which is a beneficial factor for integrationwith district heating networks, biofuel upgrading plants andcombined heat and power plants. The conclusion of the study is that a variety of energyproducts such as heat, unrefined biofuel, pellets andelectricity can be efficiently produced in the sawmill industryand sold for profit to external customers. The payback periodsfor the proposed investments are moderate and both theemissions of volatile organic compounds and global CO2 aredecreased. Should the proposed measures be fully implemented atSwedish sawmills, about 2.8 TWh of biofuel could be savedannually, 0.5 TWh of waste heat could be sold as districtheating and 0.8 TWh of green electricity could be produced.Language: English Keywords:Sawmill industry, energy efficiency, heatrecovery, integration, biofuel, upgrading, district heating,fuel pellets, CHP, VOC, CO2

The European Union faces challenges related to climate change, security of energy supply, and competitiveness of European industries. Energy efficiency indicators are required for monitoring and controlling the effectiveness of policies such as the recently endorsed Energy Efficiency Directive. This thesis aims at assessing whether traditionally used energy efficiency indicators capture the development of energy efficiency in the iron and steel sector. The study is based on results from two statistical methods: a top-down, i.e. Malmquist productivity index, and a bottom-up, i.e. partial least squares regression. The specific energy consumption (the indicator representing the sector within the Odyssee energy efficiency index) was scrutinised together with associated indicators based on economic production using the aforementioned statistical methods. The results demonstrated the specific energy consumption does not capture the characteristics of the value chain of steel products. Therefore, it is not sufficient for capturing the energy efficiency of iron and steel industries. Previous studies suggest using indicators based on economic production (e.g. value added) since they represent the value chain to larger degree. However, the value creation process of companies belonging to larger international groups cannot be estimated reliably. Furthermore, the trends of both types of indicators tend to be highly influenced by structural changes, veiling the actual efficiency development. Energy use statistics published by international organisations were also compared for the Swedish case. The results demonstrated that international organisations use different methodologies for allocating energy use statistics between consumption and transformation sectors. The method has significant implications on the trends observed, if based on openly available statistics. This thesis complements previous research by reviewing implications of traditional energy efficiency indicators based on company data, national statistics or openly available statistics and contributes with insights essential for future efforts towards improving energy efficiency indicators for the steel industry. / Den europeiska unionen står inför utmaningar relaterade till minskad klimatpåverkan, säkerställd energitillgång samt konkurrenskraften hos europeisk industri. Energieffektiviseringsindikatorer krävs för att övervaka och kontrollera effektiviteten hos energipolicy såsom det nyligen antagna energieffektiviseringsdirektivet. Den här avhandlingen syftar till att bedöma om traditionellt använda energieffektiviserings-indikatorer fångar järn- och stålsektorns utveckling inom energi-effektivitet. Studien är baserad på resultat från två statistiska metoder: en top-down-metod, Malmquists produktivitetsindex, och en bottom-up-metod, partiella minsta kvadratmetoden. Den specifika energikonsumtionen – indikatorn som representerar sektorn i Odyssees energieffektiviseringsindex – granskades tillsammans med andra energieffektivitetsindikatorer med hjälp av de ovan nämnda statistiska metoderna. Resultaten visade att specifik energikonsumtion inte fångar karaktären av stålprodukternas värdekedjor. Indikatorn är därför inte tillräcklig för att fånga energieffektivitet inom järn- och stål-industrier. Tidigare studier föreslår att använda indikatorer baserade på ekonomisk produktion (exempelvis förädlingsvärdet) då de representerar värdekedjan till högre grad. Förädlingsvärdet kan dock inte uppskattas tillförlitligt för företag som tillhör större internationella grupper. Trend-erna hos båda typerna av indikatorer tenderar dessutom att påverkas av strukturella förändringar, vilka döljer den riktiga effektivitetsutvecklingen. En jämförelse gjordes även av energianvändningsstatistik publicerad av olika internationella organisationer för det svenska fallet. Resultaten demonstrerade att internationella organisationer använder olika metoder för att allokera energianvändning mellan konsumtions- och omvandlings-sektorer i statistiken. Metoden påverkar observerade trender signifikant om de baseras på öppet tillgänglig statistik. Avhandlingen kompletterar tidigare forskning genom att belysa innebörden av traditionella energieffektiviseringsindikatorer baserade på företagsdata, nationell statistik eller öppet tillgänglig statistik samt bidrar med insikter som kommer att vara väsentliga för framtida satsningar i att förbättra energieffektiviseringsindikatorer för stålindustrin.

<p>QC 20140227</p>

In this paper, the aim is to research green coding and sustainability within web development. Can environmentally friendly web development make a difference in climate change? In which ways can a web developer code green? And to what extent are programmers today aware of the phrase “green coding”? These are the key questions that will be discussed in the essay. The goal is to research the current recognition of environmentally friendly coding within the programming community. To give examples of eco-friendly development and research its relevance as a tool for combating climate change. The paper will attempt to answer if it has a significant enough effect on global emissions for society to care about, or explain why such a conclusion is difficult to ascertain. This study proceeded accordingly when answering the questions. Firstly, a survey was created with questions about green coding and eco-friendly development and then shared with a group of programmers. Secondly, previous studies were collected to see how well their research fit together and what conclusions can be drawn from it. Thirdly, information and data from statistics were collected together with test measurements in order to identify energy-efficient ways of coding and developing. The results from gathering and comparing sources of energy consumed from data being transferred show that it is difficult to calculate the impact eco-friendly development has on climate change. Some techniques and tools that are preferable when prioritizing energy efficiency are revealed. The results of the survey showed that there is some recognition of the phrase “green coding” among programmers but not widespread and that there is a minority of the respondents who think about saving energy when coding and choosing tools and techniques.

This thesis summarises the outcomes of a Big Data analysis, performed on a set of hourly district heating energy consumption data from 2012 for nearly 15 000 buildings in the City of Stockholm. The aim of the study was to find patterns and inefficiencies in the consumption data using KNIME, a big data analysis tool, and to initiate a retrofitting plan for the city to counteract these inefficiencies. By defining a number of energy saving scenarios, the potential for increased efficiency is estimated and the resulting methodology can be used by other (smart) cities and policy makers to estimate savings potential elsewhere. In addition, the influence of weather circumstances, building location and building types is studied. In the introduction, a concise overview of the concepts Smart City and Big Data is given, together with their relevance for the energy challenges of the 21st century. Thereafter, a summary of the previous studies at the foundation of this research and a brief theory review of less common methods used in this thesis are presented. The method of this thesis consisted of first understanding and describing the dataset using descriptive statistics, studying the annual fluctuations in energy consumption and clustering all consumer groups per building class according to total consumption, consumption intensity and time of consumption. After these descriptive steps, a more analytical part starts with the definition of a number of energy saving scenarios. They are used to estimate the maximal potential for energy savings, regardless of actual measures, financial or temporal aspects. This hypothetical simulation is supplemented with a more realistic retrofitting plan that explores the feasibility of Stockholm’s Climate Action Plan for 2012-2015, using a limited set of energy efficiency measures and a fixed investment horizon. The analytical part is concluded with a spatial regression that sets out to determine the influence of wind velocity and temperature in different parts of Stockholm. The conclusions of this thesis are that the potential for energy savings in the studied data set can go up to 59% or 4.6 TWh. The financially justified savings are estimated at ca. 6% using favourable investment parameters. However, these savings quickly diminish because of a high sensitivity on the input parameters. The clustering analysis has not yielded the anticipated results, but they can be used as a tool to target investments towards groups of buildings that have a high return on investment.

Ice rinks are among the most energy intensive public buildings in developed and developing countries. According to a research on Swedish ice rinks; a typical ice rink consumes approximately 1185 MWh/year which leads to more than 300 GWh/year for the 342 Swedish indoor ice rinks. The refrigeration system is usually the largest consumer by 43% average share of the total energy consumption.  To decrease the refrigeration system energy demand, there are a variety of energy efficiency techniques known and available but the key to select the best ones is finding the major heat loads on the ice sheet and refrigeration system, which is unique for each ice rink. To fulfil this objective and in addition to review literature, this study has two main approaches. The first approach is to measure and evaluate the performance of the refrigeration system in two ice rinks, called Norrtälje and Älta. The estimated cooling capacity is approximately equal to the total heat load on the ice plus the heat gains in the distribution system. This goal has been accomplished by using a performance analyser called “ClimaCheck” which is based on an “internal method” because it uses the compressor as an internal mass flow meter and consequently, there is no need for an external one. The refrigerant mass flow rate is calculated by an energy balance over the compressor. By knowing the mass flow, enthalpy of the refrigerant, etc. the cooling capacity and COP of the system can be calculated. While the total heat load is known by the first approach, the second approach tries to discover different heat loads shares by analytical modelling. The measured physical and thermodynamical parameters plus the ice rink geometrical characteristics are input to the heat transfer correlations to estimate the heat load magnitude. The results of the measurements show that the total energy consumption in Norrtälje is about two third of Älta. The main reasons for this less energy consumption are smarter control systems for compressors and pumps, better ventilation distribution design and 1°C-2°C higher ice temperature.      Analytical modelling for a sample day has estimated that about 84% of the total heat loads is originated from the heat loads on ice sheet while the distribution system causes the remaining 16%. Moreover, calculations show that convection plus small portion of condensation (altogether 36%), radiation (23%), ice resurfacing (14%) and lighting (7%) are the largest heat loads in winter while in summer condensation is another significant heat load (10%). Comparing two six-hour periods, one without ice resurfacing and four resurfacings in the second one, 30% more cooling demand has been calculated for the second period. Furthermore, it has been shown that the evaporator to brine is the contributor for 66% of the heat transfer resistances from ice to evaporator while brine to bottom ice and bottom to top ice accounts for 27% and 7% respectively. To conclude, a parallel “performance analysis of the refrigeration system” and “heat loads estimation” proves to be a useful tool for adopting proper design and control for energy efficient operation. / Stoppsladd financed by Swedish Energy Agency (Energimyndigheten) and Swedish Ice Hockey Association

Currently 341 ice rinks are in operation in Sweden with an estimated total energy consumption of 384 GWh/year. As it has been revealed in previous studies, most of the ice arenas are constructed and/or not operated efficiently. Thus it is considerable energy saving potential, which could be achieved in this area. The potential is even more significant if one can consider the savings in the ice rinks all over the world. This report is an in-depth study, which aims at analysing the Swedish ice rinks energy consumption and estimation of the corresponding energy saving potential. The report analyses the energy statistics obtained through the Stoppsladd study, which includes the ice rinks inventory, data collection and compilation of energy relevant data for 100 ice rinks located in Sweden. The inventory has revealed a number of important statistical figures, such as total energy consumption average in total (estimated to be 1,137 MWh/year) and for different ice arenas categories in particular. Relevant specific energy consumption values as well as a number of other important figures are also provided in the paper, thus giving an idea on the way to minimise energy consumption at each specific ice rink. The results are additionally supported by statistical multifactor regression analysis, which resulted in a relation between the ice rink’s total energy consumption and some known factors values affecting it. Two in-depth studies fulfil the Stoppsladd project by analysing water quality and ice quality effect on the ice rink’s energy consumption and investigation of the static and dynamic heat flow distribution in ice rink slab. A static heat flow distribution model of an ice rink evaluated the effect of concrete  with different properties on temperature and heat flow distribution within an ice rink floor slab. The study proves that the ice rink refrigeration system COP2 could be increased with 3.5 % just implementing new high thermal conductivity concrete layer into the conventional concrete ice rink floor. The static analysis results were further completed with dynamic analysis, which adequately reflects the thermodynamic response of the concrete ice rink floor to a varying heat load. As a result, the thesis represents a holistic approach to the ice rink energy efficiency increase problem and provides a good basis for further studies in relevant areas. It is proved that modified concrete allowing higher (efficient) secondary refrigerant tempera­tures and also provides better response to change in heat load to the system. / Stoppslad

The Swedish government in the 1960th initiated “The Million Program” to build million residentialunits to cover the housing shortage between 1965 to 1975. Tjärna Ängar neighborhood in Borlängemunicipality was built during the million-program period, where these residential units became old,and the indoor environment is uncomfortable for the residents.Recently, there have been extensive energy-efficient renovations to improving the energyefficiency,indoor air quality, and thermal comfort of these buildings. The renovation project, withcooperation between Dalarna University and the local housing company (Stora Tunabyggen)started in 2015 by renovating three buildings in the Tjärna Ängar neighborhood.This study was conducted at one of these three retrofitting buildings (Kornstigen 25) to investigatethe thermal comfort in the building following energy retrofit. The assessment of the thermalcomfort in this study is based on Fanger's model with the use of predicted mean vote (PMV) andpredicted percentage of dissatisfied (PPD) to assess the obtained measurements.An online questionnaire survey with building occupants was conducted to give a betterunderstanding of the current situation of the retrofitting building before and after the renovationregarding thermal comfort. Based on the measurement, the thermal sensation of the occupants isslightly cool according to the standard’s sensation scale during the period of the measurement. Anonline questionnaire survey assures that the occupants were feeling slightly cool during someperiods of the day inside the apartments.