The borehole heat exchangers of today suffer from poor thermal and hydrodynamic performance. The purpose of this thesis is to improve the performance of ground source heat pump systems and thermal energy storages by increasing the energy efficiency of the borehole heat exchangers. For this reason, the annular coaxial borehole heat exchanger (CBHE) has been analyzed. This type of heat exchanger is interesting in terms of both thermal and hydrodynamic performance. A model has been set up in the program Comsol Multiphysics in order to investigate the heat transfer characteristics along the borehole.

As a part of the fight against the global warming the energy production needs to be more efficient and redirected towards sustainable options. One alternative is cogeneration, which means that electricity and heat is produced in one plant. The purpose with this survey is to examine if there are any commercial available combined heat and power techniques, based on combustion of solid moist biomass, which are suitable to small-scale applications. The technique must be able to produce between 2 and 10 MW thermal and the heat demand is a Swedish district-heating system. When already published reports had been studied, the Organic Rankine Cycle (ORC) was chosen as the most suitable technique.

Sweden?s energy consumption is divided into three major sectors. One of them is the industry sector. One third of Sweden?s energy consumption is converted in the industries.

Gtherm is an innovation company who has an unique air heat exchanger underdevelopment. The purpose of this thesis is to provide data of suitable motors for theheat exchanger and to find suitable motor suppliers.A motor specification was designed. It is an important basis for the search of suitablemotors. A compilation was made of nine motor suppliers and the suitable motorsfrom those. The compilation can be used by GTherm in their choice of suppliers andmotors.The compilation of the demands on the motor and analysis of suppliers indicated thatthere were no standard motors available to GTherms air heat exchanger.

Our purpose in this paper is to examine if there is any profitability for a company with a factory in the timber industry to invest in a combined heat and power, CHP. Based on analysis and the results that the paper generates, we will give Derome AB a suggestion on how it is a profitable investment or not to installing in a CHP.By investing in a CHP plant, you can get a high efficiency, which means that companies can use their resources more effectively. The Swedish wood industry has by-products of production that can be used for combustion in their boiler which is an advantage.The essay is a qualitative study where we have a case company, Derome AB. In this company, we interviewed two employees who have knowledge in the study. They have helped us to provide information and data about their business.We chose to use the pay-off- and the net present value method, NPV, to see if there are profitable advantages for the investment.

In query expansion (QE) terms are added to an initial query in order to improve retrieval effectiveness. In this thesis we use QE in the sense that a reformulation of the query is done by deleting the terms in the initial query and instead replacing them with terms from the documents retrieved in the initial run. The aim of this thesis is to, in a experimental full text invironment, study and compare the retrieval result of two different query expansion strategies in relation to each other. The following questions are addressed by the study: How do the two strategies perform in relation to each other regarding recall? What may be causing the result? Are the two strategies retrieving the same relevant documents? Two strategies are designed to simulate a searcher using automatic query expansion (AQE) either with or without relevance feedback.

The dishwasher is a wide spread product that occurs in many households. It saves the user time,water and energy. When using a dishwasher instead of doing dishes by hand a lot of energy issaved.The importance of lowering the energy consumption does not only come from the consumerwinnings but also from an environmental point of view. Scientists are certain that the globalwarming comes from the emission of green house gasses that is created by human consumptionof oil, gas and coal.Dishwashers today are a lot more energy efficient than older dishwashers, but there are stillmargins to lower the energy consumption. The aim with this project is to investigate thedishwasher and it?s washing cycle, noting different phases and components that contribute towaste of energy.

The aim of this thesis is to develop a new business model for district heating and cooling firms which can contribute to a stabilization of the Swedish national energy system. The business model is developed for a district heating and cooling firm and is exemplified with Fortum Heat. The theoretical investigation around the topic creates a rigid base for following qualitative empirical studies. Osterwalder?s canvas for business model generation is used together with a Casual Loop Diagram to identify a number of business opportunities which stabilizes the national energy system.

Denna uppsats behandlar svårigheter och möjligheter som finns när ett fastighetsmäklarföretag expanderar på en marknad med stor konkurrens. I de tre storstadsregionerna är konkurrensen mellan de olika fastighetsmäklarbyråerna mycket stor. Vad är det då som får nya aktörer att försöka slå sig in på dessa marknader..

The study aims to reduce energy consumption in apartment buildings where individual metering and charging of heat is applied. The aim is to develop planning and design for individual metering and charging in apartment buildings.The study is based on literature review, interviews and case study that include analysis of existing documents. Interviews were carried out with the property developer and the involved consultants who planned the apartment building Yasuragi. To investigate the differences the condominium association has noted in heat consumption between flats, the debit values of the heat were used to discern which houses that were furthest from the average consumption. On these flats there were temperature measurements and thermal photo shoots made for discriminating behavior and possible construction techniques which could be the explanation for the heat spread.Boverket shows that the consumption of heat can be reduced by 10-20% after insertion of individual metering and charging in an apartment block.

This degree project handles acoustic measurements of the heat pump EcoAir 107, made by Enertech CTC AB. The sound from the three sound sources of the heat pump, fan, compressor and four way valve, have been measured to find out how they affect the total sound level of the product.Measures to attenuate the sound level have been developed and tested. By comparing these with the sound of the heat pump, in its original state, we have found out the measures which have best effects.The best attenuating measures came to be: taped openings and holes around the compressor space, isolating the top and the bottom of the whole construction, support of the fan bottom part and shielding of the sound source with a screen at a distance of 110 mmThese measures have been tested together and an average attenuation of the total sound level with 3,9 dB have been accomplished. In the front of the fan where the continuous sound is the strongest, the attenuation was 4,7 dB.This project is meant to be used as a guide by Enertech CTC AB:s during their future developing process..

This report is made as a literature review, focusing on the work done to increase understanding of efficiency in the categories of substations and secondary heating systems, with respect to the deviation from the theoretically possible cooling off in the distribution network as well as the economic benefit that appear. The main purpose of a considerable part of the literature used in this report addresses the issue of identifying individual causes of reduced cooling in district heating systems. These literature resources have been compiled and summarized as part of the report.The technology of district heating is associated with benefits such as better use of the energy in a fuel. This is the case of cogeneration plants where serial generation of electricity and thermal energy increases efficiency compared with the parallel generation where heat is generated locally and electricity is generated centrally. Serial generation thus allows for lower primary energy demand.

The purpose of this report is to document the experiments carried out, methods used and results gained during research into how the silicon content of an aluminium alloy affects the coefficient of thermal expansion (CTE).The goal of this paper is to better understand and to find a relation between silicon content and the coefficient of thermal expansion.Experiments were carried out using carefully prepared samples of Al Si alloys (0, 7, 10 and 20% Si content). Using these alloys, the CTE could be measured using a dilatometer.Comparative analysis carried out could map the effects of silicon content on the coefficient of thermal expansion and an equation was created. Using simple graphs and the rule of mixture method, the authors were able to build a simple tool for calculating the CTE of specific aluminum silicon alloys..

An investigation of the heat impact of laser cutting on the material properties when producing tensile and impact test specimens of different steel types of varying thickness has been performed. The purpose of the thesis project was to provide recommendations regarding how much material that needs to be milled from the laser cut edge before tensile and impact tests. The study has been performed partly by investigating the test specimens by heat camera when the specimens were cut in the laser cutting line and partly by performing hardness tests, investigation by microscopy, and tolerance and roughness measurements and tensile tests of the laser cut material and material produced in the traditional multi operation machine. The results show that the heat affected zone in the thicker materials is greater than previously thought of, and that the currently used recommendation has to be adjusted. The study clearly shows that the thicker the material, the greater the heat affected zone, independently of the steel type, since the thicker material takes longer time to cut.

To achieve the requirements to decrease emissions of greenhouse gases by 20 % by 2020, Swedenneeds to increase its use of bioenergy. In doing so it seems natural that those who already haveaccess to large amounts of biofuels in the form of by-products such as straw, wood chips anddigestible materials take advantage of these assets locally. By combining production of heat withpower production at the farm it may be possible to not only reduce the direct use of fossil fuel forheating but also reduce energy costs.The purpose was to simulate different cases of using a small scale biofueled combined heat andpower plant for farm-based systems. A MatLab-model was developed and used to draw conclusionsabout the costs for production of heat and electricity with different conversion technologies.The model uses climate data to simulate the variations in heat energy demand on a day-to-day basis.The given heat demand is the base of the simulation and from this the possible electric output iscalculated. This study has focused on the impact of the following properties: electric-, heat- andtotal efficiency, fuel, fuel price and specific fuel requirements.