The use of silicon carbide (SiC) as a base material in power electronics has manyadvantages, including high breakdown voltage and excellent temperature endurance.However, the packaging of such electronics presents major challenges and there is aneed for packaging that can operate in higher temperature. The purpose of this thesishas been to develop a test method and verify the functionality of SiC powertransistors prototypes with a new packaging technique developed by Swerea IVF AB.It includes setting up an electrical test-bed for power and high temperature cyclingand analysis of the results. Even though test confirmed functionality after thepackaging process, (at room temperature) the performance seemed to have been reduced. This could be a result of the measurement setup and the packaging process.In higher temperature the transistors failed to operate longer than a couple ofminutes which showed the weaknesses in the design and the challenges with this typeof packaging..

A Swedish electronics company wants to make the cooling of one of their electronic components more efficient. They propose that a retrofit liquid cooler is the way to achieve this goal. The current air cooling has high energy cost due to the high amount of power needed to power fans and heat exchangers. Using high volumes of air for cooling also leads to noise pollution. The conversion from air to liquid cooling would possibly make the operation of the electronics more cost efficient and less noisy.The purpose of this project is to theoretically evaluate different concepts of drawing the heat generated by the electronic component in to a fluid, using numerical calculations in Matlab and FEM simulations in ANSYS.

The goal of this thesis work is to enable an existing UHF radar to operate in the VHF band instead. In order to achieve this, new coherent local oscillators are required. Different options are suggested and one of them is implemented and analyzed..

The project focus on combustion of softwood pellets and pellets in a 40 kW grate fire reactor at TEC-Lab. Dept Applied Physics and Electronics at Umeå University. Experiments were performed at four primary airs to fuel ratios (0.7 to 1.3), where aspects such as temperature profile, levels of gases (CO and NO), sintering-/-slagging and unburned fraction of the ashes were studied. Four different fuel loads were used for wood pellets (10, 20 and 30 kW) and one fuel load for straw (10 kW). Combustion of straw proved very difficult to ignite, and also led to other combustion-related technical problem such as slag formation due to the relatively low melting temperature-/-slag temperature of the straw.

The aim with the thesis is to get deeper knowledge in one of the subjects botany, livestock technology or economy. I have chosen to get deeper knowledge in how to store potatoes. How are you going to act to keep the quality on the potato during the storage, with a minimum of weight lost? My aim with this thesis is to get a view over how the potato act in storage space. The storage environment is very important in the storage space.

Today electronics becomes more and more complex and to keep low costs and power consumption, both digital and analog parts are implemented on the same chip. The degree of automization for the digital parts have increased fast and is high, but for the analog parts this has not come through. This have created a big gap between the degrees of automization for the two parts and makes the analog parts the bottleneck in electronics develop. Research is ongoing at Electronics systems group at Linköping University target the increase of design automization for analog circuits. An optimizationbased approach for device sizing is developed and for this a good optimization method is needed which can find good solutions and meet the specification parameters.

In this final thesis a rough description of aluminium extrusion is made, the importance of temperature of both the raw material and the extruded profile for a good profile quality. The difficulty in controlling these temperatures are discussed and attempts to increase the control are described. The attempts are basically made by controlling the furnace that is heating the raw material. This is done in a manner that the raw material reaches its final temperature shortly before it is extruded. An IR-camera at the press can be used for profile temperature measurements.

SAPA´s resource of waste heat is the basis for this thesis to investigate the possibility of energy assets in their cooling water and possible uses for it. The energy in the waste water is greater than the current need which has three uses which are (1) heating the factory, (2) converting liquid propane to propane gas and (3) local domestic heating. The average energy load that is available is 1, 7 MW and the average temperature in the cooling water is 41°C. The total energy load at dimensioning out side temperature is approximately 1,6 MW for the three current uses. The temperature is currently too low to be used directly in the existing systems so an upgrade is needed.

AbstractWith increasing population and increasing demands for comfort and thus an increase in energy demand, it is necessary to examine various energy-efficiency measures. This work deals with the ability to control the flow through the heating system to achieve the desired comfort with as little energy as possibleA heating system contains of different parts, roughly speaking, you can divide it to three main components: Heat source, Distribution and Heat emitters. All components are working together to bring heat to the building. What is examined in this report are different ways of adjusting the flow and supply temperature and how it affects comfort and energy use in a building.At today ?s date the conventional method is to use a high flow through the heating system, which affects pressure drop and cooling of the fluid.

This report examines the prerequisites for LEDs to replace other technologies indifferent applications. How does the different technologies for light generationwork and what are the advantages and disadvantages? The various technologieslimitations and characteristics provides the opportunities for the LEDs.This report describes a test-construction built to examine what practical arrangementscan be built with modern light emitting diodes, in order to showsome of the possibilities. The construction consists of three different applications,a high power lamp based on cold white LEDs, one based on warm whiteLEDs for the evaluation of the light characteristics and a RGB-LED based lampable to mix any colors quickly and seamlessly. The test construction also containsthe essential peripherals including control-electronics, optics and a custombuilt watercooling solution.The potential for LEDs is huge but it is complicated to build LED based applicationsdue to the limitations which mainly includes the electronics and theneccesary cooling.

Nimo Verken AB is the leading producer in the Scandinavia of drying cabinets. The construction has, with small changes, been the same since the 70s with a thermostat and a timer as controlling system. There was a wish to develop a modern cabinet which showed remaining time on a display and with energy saving functions.In this report we go through how it is possible to implement a digital controlling system, where remaining time is shown on a display and where it is possible to choose a preset ?program?.The report first presents the fundamental theory for a PIC, where we describe the different registers, how interrupts are handled, the internal clock function and how data is sent to control the different parts of the construction.Next the report presents and describes the new hardware that is needed, such as the encoder, the temperature sensor and the display.After the theory we describe how the program in the PIC may be drafted. Last in the report we have the result of the tests of the temperature variations and the accuracy of the time..

The district heating load is seasonally dependent, with a low load during periods of high ambient temperature. Thermal energy storage (TES) has the potential to shift heating loads from winter to summer, thus reducing cost and environmental impact of District Heat production. In this study, a concept of high temperature borehole thermal energy storage (HT-BTES) together with a pellet heating plant for temperature boost, is presented and evaluated by its technical limitations, its ability to supply heat, its function within the district heating system, as well as its environmental impact and economic viability in Gothenburg, Sweden, a city with access to high quantities of waste heat.The concept has proven potentially environmentally friendly and potentially profitable if its design is balanced to achieve a good enough supply temperature from the HT-BTES. The size of the heat storage, the distance between boreholes and low borehole thermal resistance are key parameters to achieve high temperature. Profitability increases if a location with lower temperature demand, as well as risk of future shortage of supply, can be met.

This master thesis was carried out for Saab Avitronics, a business unit of Saab ABactive in electronic systems for military aircrafts. Reliability and weight are of crucialimportance in this environment. To improve reliability and lower the weight graphitemay be used for electronics cooling. Graphite is an anisotropic material and hasthereof high thermal conductivity in two directions (in-plane) and a relatively lowconductivity in the third direction (through thickness).The purpose of this thesis was to investigate if graphite is an adequate thermalconductor to use in PCB carriers. The carriers support and cool the PCB by divertingthe heat dissipation from the PCB components to the edge.

This thesis examines a possible control strategy to minimize flow fluctuations in Uppsala?s district heating system. High variations in flow rate may lead to complications caused by hydraulic constraints in the district heating system. These complications, such as inadequate pressure and temperature levels, increase the risk of heat delivery failures. It is therefore important to avoid such situations both for the producer and for the customers.Typically, the forward temperature is controlled by using a rough correlation with respect to the outdoor temperature.

Glass has sophisticated front properties and are used as facades in high buildings. During cold periods, these glass facades could cause thermal discomfort, due to cold downdraught. Cold downdraught can be countered by placing heaters under glass surfaces. Nowadays technology offers highly insulating windows, which is why there is an interest to investigate the indoor climate with only underfloor heating. The research in this area is limited, and few empirical methods are available.