Energy Efficiency through Thermal Energy Storage : Possibilities for the Swedish Building Stock

The need for heating and cooling in buildings constitutes a considerable part of the total energy use in a country and reducing this need is of outmost importance in order to reach national and international goals for reducing energy use and emissions. One important way of reaching these goals is to increase the proportion of renewable energy used for heating and cooling of buildings. Perhaps the largest obstacle with this is the often occurring mismatch between the availability of renewable energy and the need for heating or cooling, hindering this energy to be used directly. This is one of the problems that can be solved by using thermal energy storage (TES) in order to save the heat or cold from when it is available to when it is needed. This thesis is focusing on the combination of TES techniques and buildings to achieve increased energy efficiency for heating and cooling. Various techniques used for TES as well as the combination of TES in buildings have been investigated and summarized through an extensive literature review. A survey of the Swedish building stock was also performed in order to define building types common in Sweden. Within the scope of this thesis, the survey resulted in the selection of three building types, two single family houses and one office building, out of which the two residential buildings were used in a simulation case study of passive TES with increased thermal mass (both sensible and latent). The second case study presented in the thesis is an evaluation of an existing seasonal borehole storage of solar heat for a residential community. In this case, real measurement data was used in the evaluation and in comparisons with earlier evaluations. The literature reviews showed that using TES opens up potential for reduced energy demand and reduced peak heating and cooling loads as well as possibilities for an increased share of renewable energy to cover the energy demand. By using passive storage through increased thermal mass of a building it is also possible to reduce variations in the indoor temperature and especially reduce excess temperatures during warm periods, which could result in avoiding active cooling in a building that would otherwise need it. The analysis of the combination of TES and building types confirmed that TES has a significant potential for increased energy efficiency in buildings but also highlighted the fact that there is still much research required before some of the technologies can become commercially available. In the simulation case study it was concluded that only a small reduction in heating demand is possible with increased thermal mass, but that the time with indoor temperatures above 24 °C can be reduced by up to 20%. The case study of the borehole storage system showed that although the storage system worked as planned, heat losses in the rest of the system as well as some problems with the system operation resulted in a lower solar fraction than projected. The work presented within this thesis has shown that TES is already used successfully for many building applications (e.g. domestic hot water stores and water tanks for storing solar heat) but that there still is much potential in further use of TES. There are, however, barriers such as a need for more research for some storage technologies as well as storage materials, especially phase change material storage and thermochemical storage.

Informationsförvaltning inom en stor organisation : En fallstudie på Trafikverket

Denna studie syftar till att undersöka hur en stor organisation arbetar med förvaltning av information genom att undersöka dess nuvarande informationsförvaltning, samt undersöka eventuella förslag till framtida informationsförvaltning. Vidare syftar studien också till att undersöka hur en stor organisation kan etablera en tydlig styrning, samverkan, hantering och ansvars- och rollfördelning kring informationsförvaltning. Denna studie är kvalitativ, där datainsamlingen sker genom dokumentstudier och intervjuer. Studien bedrivs med abduktion och är en normativ fallstudie då studiens mål är att ge vägledning och föreslå åtgärder till det fall som uppdragsgivaren har bett mig att studera. Fallet i denna studie är ett typiskt fall, då studiens resultat kan vara i intresse för fler än studiens uppdragsgivare, exempelvis organisationer med liknande informationsmiljö. För att samla teori till studien så har jag genomfört litteraturstudier om ämnen som är relevanta för studiens syfte: Informationsförvaltning, Business Intelligence, Data Warehouse och dess arkitektur, samt Business Intelligence Competency Center. Denna studie bidrar med praktiskt kunskapsbidrag, då studien ger svar på praktiska problem. Uppdragsgivaren har haft praktiska problem i och med en icke fungerade informationsförvaltning, och denna studie har bidragit med förslag på framtida informationsförvaltning. Förslaget på framtida informationsförvaltning involverar ett centraliserat Data Warehouse, samt utvecklingen utav en verksamhet som hanterar informationsförvaltning och styrningen kring informationsförvaltningen inom hela organisationen.