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227 Uppsatser om Thermal cracks - Sida 3 av 16

Bergerosion i utskovskanaler

Today?s climate changes will probably give rise to precipitation in Sweden, which will cause more floods in Swedish rivers. Many of the Swedish rivers are regulated and have lots of hydro-electro power plants. Higher floods in the rivers will give greater water loads on the dams, which mean that a higher discharge through the sluice gates and in the spillway channels is needed. High discharge of water in a spillway channel can create scour of the material in the channel.

Utvärdering av fjädrande statorfötter : Nytt koncept i vattenkraftgeneratorer

This thesis is an evaluation of a new design concept for statorfeets in Gallejaur hydro power plant. Founder of the work is Vattenfall AB Vattenkraft. During the 70- and 80´s nuclear power began to be phased in to the Swedish grid, which meant that hydropower became an important source of rules. The generators began running in so called intermittent operations instead of basic operations, which meant 300-600 start/stop per year instead of one-ten numbers start/stop per year. In order to deal with the thermal forces that arise at every start and stop suppliers began to mount so called sliding joints, which is to take advantage of these forces and maintain the stator shape.

Lagring av kyla med horisontella markvärmeväxlare för kylning av koncepthus i Mellanöstern

Norconsult AB has developed a solarhousing concept, a house designed for the warm climate in the Middle East andwith large quantities of solar panels installed. The cooling system for the house was designed in an earlier report, the purpose of this thesis is to investigate the possibility of short and long term storage of thermal energy via an underground energy storage volume.Two different designs of the storage and three different filling materials have been integrated into a model to simulate different cases. The first design consisted of pipes installed in the ground, without insulation. The second design consisted of an insulated concrete box installed to prevent thermal energy from the surrounding soil to flow towards the lower temperature regions within the storage. The three different filling materials were dry saudi sand, water saturated saudi sand and the filling material used by the client for energy storage in Sweden.The results from the simulations show that neither of the designs, regardless of the filling material, managed to extract enough thermal energy from the house to the ground to uphold the demands of indoor climate.

Undersökning av förskolan Temmelburken certifierad enligt Miljöbyggnad : Termiskt klimat, energianvändning och höjning av certifieringsnivån

WSP building physics in Stockholm has certified the preschool Temmelburken in Bromma with the system of certification Miljöbyggnad. The rating of the building became BRONZE. In this thesis the preschool has been investigated with respect to the three areas: thermal climate, use of energy and improving of the level of certification. The thermal climate at the preschool has been investigated by a questionnaire survey and by measurements in order to do comparisons between the results from the two investigations as well as with the results of the simulations that WSP has done at the certification of the preschool. The differences between the results from the simulations and the questionnaire survey for winter as well as from the measurement performed with a comfort meter the 19th of March are concidered to be reasonably small since they give rise to the same rating according to Miljöbyggnad.   Operational data for the use of energy for the preschool have been obtained in order to do comparisons with simulations performed by WSP and Svenska Besiktningar AB. The comparison shows that the simulated values for the specific use of energy are lower than what the real specific use of energy would be for the preschool, since just the operational data for the heat energy is higher than the simulated values. At the investigation of the possibility of improving the level of certification it was found that the rating of the preschool can be raised from BRONZE to SILVER by improving the ratings of the ?thermal climate summer? and the ?daylight?.

Optimering av OTEC-system

Ocean Thermal Energy Conversion, OTEC, is a sustainable energy conversion technology that is not yet commercialized. OTEC is a technology that utilizes the temperature difference in oceans between the warm surface water and the cold water at 1 000 m depth to run a Rankine Cycle. This technology can produce electricity and provide synergies like fresh water, air conditioning and aquaculture. A simulation program for three alternative OTEC systems has been created in order to decide which OTEC system is most profitable; closed, open or hybrid system. In this simulation a production cost analysis is performed in order to investigate and decide which one of the three systems that has the lowest production cost. The production cost analysis also analyzes if the profitability is affected by the size of the facility. After these analyzes, the most profitable of the three different OTEC-systems is expanded by an installation of solar collectors in order to see if the thermal efficiency is improved. The result shows that the most profitable system varies with the size of the facility.

Bacterial contamination of eggshells in deep litter floor systemsand conventional cages in Jordan

This study was carried out in Jordan with the purpose to investigate the bacterial microflora of egg shells from cage systems and from deep litter floor systems. Another aim wasto get a general impression of the hygiene, at farm level, of egg production in Jordan andthe factors affecting it.Eggs from two cage systems and three floor systems were analyzed, regarding bacterialcontamination of the egg shells. Egg samples were taken from the storage room, the eggcradle in the cage system and from the nest and floor in the floor system. To get a generalimpression of the hygiene at the farms, swab tests and air tests were performed. Swab testswere performed with a sterile cotton swab at the same units as the eggs were sampled andair tests were performed by opening petri dishes where the hens were staying.

Hållfasthetsegenskaper i gjutjärn : tensile properties of cast iron

In the last few years people have become more and more aware of how humanity is affecting the climate. In the direction of reducing the greenhouse gases is to design engines with higher tensile properties and reduced weight, in order to achieve lower fuel consumption and cleaner fuel incineration in today's truck engines.In order to achieve these requirements it?s necessary to increase the combustion pressure in the engine. This requires higher tensile properties and high thermal conductivity of the engine material. The department of Component Technology at the University of Jönköping in collaboration with Volvo Powertrain AB, Scania CV AB and DAROS Piston Rings AB has been commissioned to develop this material and to find knowledge of material properties used in truck engines and piston rings used for marine applications.The purpose with this work is to analyze the tensile properties of a series of cast iron, cast under different metallurgical conditions.Four different series of cast irons have been analyzed from four points of view, carbon concentration, nodularity, amount inoculation and cooling rate.After the tensile test all specimen data was analyzed in a mathematic calculation program called Matlab 2006a.

Solenergi på Nya Karolinska Solna

In today?s society climate change has grown to one of the largest global issues. To reduce emissions of greenhouse gases, large changes of the energy system are required. An increasingly popular solution is investments in local production of renewable energy resources like wind, solar or geothermal power. The following report examines the possibility for implementing a solar power plant on the new hospital Nya Karolinska Solna. Two different technologies for extraction of solar energy has been studied, solar thermal collectors  to meet the need of heating and solar cells to satisfy the need for electricity linked to operating the hospital building.

Inventering av värmelager för kraftvärmesystem

When a combined heat and power plant produces heat and power it often faces a deficit of heat load during the summer or other periods of time. This heat is often unnecessarily cooled away or the power production has to be reduced or shut off. If it is possible to store heat from periods with low heat demand to periods with high heat demand one can get many benefits. Among these benefits are: increased power production, decreased operation with partial load, uniformly distributed load.To be able to store heat in situations like this long-term thermal heat storages are needed. In this thesis five different types of stores are presented: rock cavern storage, tank storage, pit water storage, borehole storage and aquifer storage.

Inomhusklimat i skolor- En jämförelse mellan upplevt och uppmätt inomhusklimat

Students? performance in school is dependent on the indoor climate. This report studies four schools regarding air quality and thermal environment. A survey was made at the schools as well as measurements of carbon dioxide, dampness, thermal climate and, as an indicator for the furniture?s capability to collect dust, shelf factor and fleece factor.

Restspänningar i arc-förångade (Ti(1-x)Al(x))N ytskikt

This report is the written documentation of a project work carried out at the Division of Engineering Materials at Luleå University of Technology in cooperation with Seco Tools AB. The project deals with the analysis of residual stresses in Ti-Al-N thin film grown on WC/Co cutting inserts. The composition of Al varied from 0% up to 75%. Increasing the Al content in the Ti(1-x)Alx N compound improves the compressive residual stresses even after annealing of the material. The experiments have been performed in a high temperature x-ray diffractometer (HTXRD) where the interplanar atomic spacing was determined in-situ and subsequent converted into stresses.

Hälsoeffekter från trafikbuller vid Bäckegatan

The purpose of the study is to investigate the possible effects of an unstable ventilation system and its influence on energy use and thermal comfort. The report also explores how qualified personal working with HVAC view and handles system control.In order to meet the requirements in energy efficiency and a comfortable indoor climate control regulation is a prerequisite. With optimized increased complexity of the climate systems, it becomes more challenging to control the system and the risk of unstable control increases. No previous studies about what affect an unstable system can have on energy use and thermal comfort have been found.The report is based on several tests were the controlling variable has been increased until the system becomes unstable. Two different types of unstable systems have been investigated.

Geoenergilösning för DN-huset

In this thesis proposals for different designs of a borehole thermal energy storage (BTES) have been developed for the building DN-huset in Stockholm, Sweden. To build a BTES results in savings in energy costs by approximately 44 %, i.e. 2 million Swedish crowns annually. Furthermore, a BTES would reduce the annual environmental impact with roughly 75-157 tonnes of CO2 equivalents per year, depending on how the electricity consumption?s environmental impact is estimated.

Webbportal för logistik och orderhantering : Kapsch TrafficCom AB

This thesis is ordered by Peab Sweden AB Regional Jönköping and concerns of warranty inspections.The intention is to work out a basis, which show the most common complaints is the warranty inspections, and make a small analysis on what causes them to be. The report also presents possible solutions to prevent the occurrence of defects. It also covers the issue of how the client looks at Peabs way to overcome the objections of warranty inspections. The report has the following issues:?What are the most common errors observed during the warranty inspection??What are the causes of complaints??What can be done to reduce the number of complaints??How the customer thinks that the complaints be addressed?Twenty-five Guarantee survey records from the projects Peab has done in recent years has been the starting point for the investigation.

Hur byggnadsdetaljer ändrar fasadens uttryck

An energy study has been performed on two blocks in an area called Gävle Strand. The buildings are owned by a tenant-owner?s association called brf Carolina and were built by the company Skanska 2008. The builder as well as brf Carolina are pussled by the fact that electricity use is higher than expected while heating is less. Skanska is also very interested in finding out how much heat recovery from stale exhaust air through a geo-thermal heat pump is contributing to the general heating requirement and energy balance in four out of the ten buildings located on the properties.To find possible answers to the higher electricity use a literature survey on user behaviour was conducted.

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