This thesis is performed in collaboration with Kraftpowercon AB in Surte, Sweden. Focus has been on to identify the powerlosses in one of Kraftpowercons halfbridge DC-DC converters. First theoretical calculations are made, the calculations is verified with measurements of six different operation modes. In a later stage, methods like soft switching and synchronous rectifying are proposed to increase the efficiency for the converter. To achieve softswitching for the halfbridge, the LLC resonant converter topologies are implemented and examined.

Silage is today a common feed for different animals. A general way of storing silage is in bunker silos covered with polyethylene film. The covering and uncovering is labour intensive and it is often difficult to get the silo properly sealed. Because of these reasons many American farmers leave their silos uncovered and accept the losses accompanied. One purpose of this study was therefore to examine if it sometimes can be justified to leave bunker silos uncovered.

To be able to handle tomorrows need for limited energy consumption we need to reduce our use of energy. The building sector stands for around 40 % of all energy consumption in the society. The government has put up a goal to reduce the energy consumption in our buildings with 20 % by year 2020 and 50 % by year 2050 compared with year 1995. To be able to do reach that goal we need a more energy efficient building stock.The main part of the energy used in our buildings is used for space heating. By installing ventilation systems with heat recovery on the exhaust air it is possible to use the heat-energy in the exhaust air to warm up the incoming air.

In this report the balconies? abutments for a property in Bo01-area in Malmö has been studied. The property which is called Vitruvius contains four build-ings where two of them have corbelling balconies with intermittent abutments. With intermittent abutment means that the 50 mm thermal bridge insulation that the balconies is equipped with, is broken regularly by a 300 mm concrete heel. The reinforcement bar that holds the balcony runs through this heel.

The Baltic Sea, due to its special conditions, is a unique and vulnerable marine environment. There are many pressures that have an impact on the sea and one of the major problems is the extensive flow of nutrients from land. The most visible effect of the supply of nutrients is the annual algal blooms. One of the main sources of nitrogen and phosphorus supply is agriculture. Nutrient losses from arable land have been increasing as agricultural production has intensified. At the end of the twentieth century an increased awareness of these problems led to the formation of organizations such as HELCOM and Baltic 21.

In 2011 the International Accounting Standards Board issued amendments to IAS 19 Employee Benefits. The new standard is effective from January 1st 2013 and one of the largest changes in the standard is the elimination of the corridor method. Through the corridor method companies had the possibility to defer actuarial gains and losses resulting from their defined benefit obligations (pension obligations) and leave them unrecognized off the balance sheet. According to the new standard companies reporting under International Financial Reporting Standards will have to recognize all actuarial gains and losses immediately in other comprehensive income. The aim of this thesis is to examine how the financial key ratios of Swedish listed companies will be affected by the elimination of the corridor method.

Background: Living with stroke not only means coping with physical limitations, but a stroke also leads to other losses, which in various ways may change an individual?s life. A nurse can play a significant role in regards to consequences in the ordinary day of life for patients with stroke. Aim: The aim of this literature study was to describe patients? experiences living with stroke.

Phosphorus is the single most potent contributor to eutrophication of freshwater and has also been shown to contribute to the toxic algae blooms in the Baltic sea. The dynamics and paths of losses of phosphorus from arable lands are not fully understood. It is known that phosphorus can be lost directly from plant material to water. In studies where plant material has been subjected to several freeze-thaw cycles, large amounts of phosphorus have been lost. Most studies have been conducted under field conditions, with many factors effecting the measured losses of phosphorus, such as weather and type of soil. This study was performed in a controlled environment without the presence of soil. Instead of soil, small glass beads were mixed with the plant materials in vessels, to make possible homogeneous leaching with water through the mixture of glass beads and plant materials. In this study, clover, ryegrass and dry straw were cut to pieces, approximately 2 cm long.

One step towards a more sustainable energy system is to create a more flexible electrical grid, where increased demand response among electricity consumers can play an important role. A distribution grid owner can encourage their customers to use electricity more evenly distributed during the day by introducing different types of grid fees such as time-differentiated power tariffs. In this master thesis, the theoretical economic impact of a flattened load profile for a distribution grid owner is investigated. Different factors that impact the distribution grid owner?s economy are identified and two are chosen to be quantified; losses in the grid and the fee to the feeding grid.

This thesis aims at determining the heat losses in a property vent stack and its roof valve. Upon request of a company, the vent stack is analysed for possible heat recovering solutions to be implemented, while relining of the drain system is executed and with a suitable payback time for the economic investments. The heat loss calculations are based on data for properties that are located in the Stockholm region, but also easy to change depending on the situation. The calculations are done on pipes made out of cast iron, which still is the most common type of drain pipe in Sweden, and these are the pipes that relining is usually made on. The calculations that needed to take several variables into account have been done in MatlabR2014a and the thermos dynamical properties that were used in those calculations have been extracted from EES.Three different types of heat losses in the vent stack have been taken into consideration in this thesis.

The goals of this Bachelors? Thesis were to establish the production loss through the VTIS1 Pasteur at Arla Foods Linköping dairy and then suggest simple but effective solutions to minimize the losses for each production run. If the timeframe allowed it, some of the solutions would be implemented and tested in full production to determine their impact on economic and environmental savings.The very first step of this project was to establish the statistics over what losses there is in the production pipeline through VTIS1, from milk and powders in mixer tanks to finished and packed products in cold storage. Then, when knowing how much product was actually lost and where, those bottlenecks could be pinpointed and examined more closely. At this stage the focus was switched, from the otherwise complicated and broad manufacturing process, to the VTIS1-aggregate, since early data indicated there were quite substantial losses there.In conjunction with this project Arla Foods purchased an absorption photometer-measuring device (OPTEK AS16) that could be inserted straight into the product stream out of VTIS1, allowing real time measurements of its optical density.

70 % of the lakes and waters in the water district of northern Baltic Sea do not reach the requirements for good ecological status. This is mostly due to eutrophication caused by a too high deliverance of nutrients from agricultural land or effluents. Losses of particulate phosphorus through water erosion contribute to a great extent to this eutrophication. In the action plan for the water district cover crops are mentioned as a measure for reducing losses of phosphorus from arable land. This paper reviews the possible effect of cover crops in the water district and discusses what crop that would be most suitable.

The technological legacy from the early electrification of the Swedish railroads has resulted in a power grid with a lower grid frequency than the national power grid from which it is fed. Energy transfer between these power grids with different frequencies requires substations, adapting the grid frequency for the rail road power grid. For this purpose, a feeding power grid has been built, stretching across the country from Boden in the north to Tälle/Häggvik in the south.Power transfer in the Swedish power grid results in voltage angle differences which increase with increasing loads and transfer distance. These voltage angle differences are transferred from the power feeding substations to the rail road power grid, will in some extent cause loss of energy due to unwanted power flows from north to south.To minimize the losses due to this phenomenon, a power management system called EFS 132 kV has been developed and implemented. The system minimizes the unwanted power flows and controls the desired power flow for a good distribution of loads between the power feeding substations.This thesis investigates the extent of the transmission losses avoided due to the EFS 132 kV that coordinates the idling angles to a common reference point.The results indicate that EFS 132 kV affects the power flow, especially between the northern substations through an improved load distribution.

Increased energy consumption in the world has created an increased supply of various fuels, especially fossil fuels. The Swedish government has set up various energy targets for 2020. To reach these goals it?s important to increase the energy efficiency in local buildings such as schools. This work illustrates the breakdown between energy supply and energy losses over the school.

Umeå Energi are working towards a goal, that in the year of 2018, they will be completely climate neutral. As a part of this, one target is to reduce their grid losses by 4 % of the 2012 level, which corresponds to an overall reduction of the grid losses of just over 1.7 GWh. In many residential areas, the distribution grid is designed and rated for electric heating as the heating in the houses. As many of the houses later has been converted to other types of heating, their electricity use has decreased and the total power output from many of the secondary substations has decreased significantly. Because of this, many of these stations today are well oversized, which in turn means that the energy losses in these stations are unnecessarily high.In this degree project, 25 secondary substations have been studied, all located in residential areas in and around central Umeå.