The biogas plant Kungsängens gård, owned by Uppsala Vatten och Avfall AB, produces biogas and biomanure from organic household waste, food processing waste and slaughterhouse waste. In year 2012, 4.4 million Nm3 of biogas were produced from 25 200 tons of waste. Before digestion all substrate is sanitized by one hour?s pasteurization at 70°C in order to kill pathogens. Another method, integrated thermophilic sanitation (ITS), is of interest in order to decrease the energy demand.

Heat stress negatively influences the performance of dairy cattle such as lactation and reproduction. Heat stress can cause production losses as well as welfare problems. Years of research have shown that heat stress is a huge problem for dairy cattle in both the tropics and temperate zones but no such research have so far been done in northern European countries. It seems like shade is an important tool when improving pasture conditions and therefore deserves more attention. The aim with this study was to investigate whether there is a need of providing shade for grazing dairy cows during the summer in Sweden. Two groups of lactating Swedish Red dairy cows (n=15 per group) were kept on pasture.

A district heating plant has the advantage that it can take advantage of the waste heat from industries and use of cheap fuels to produce heat. But for the long term is competitive requires that energy is also saved in district heating plants. One way to save energy in a district heating system is to increasing cooling to the return temperature. This leads to less power needed to drive the distribution pumps,  and that more energy could be extracted from the same amount of fuel by an improved flue gas condensation.In Karlskoga the return temperature into the district heating plant is high. They would therefore reduce the return temperature in order to extract more energy from the flue gases.

SAMMANFATTNING När man i tidigare undersökningar studerat betesgång för mjölkkor har klimatet på betet inte beaktats. En höglakterande ko producerar mycket värme som hon måste avge till sin omgivning för att kunna bibehålla sin kroppstemperatur. De sätt som djuret kan avge värme på är begränsade och påverkas av flera klimatfaktorer samt djurets genetiska och biologiska förutsättningar. Antalet dagar som registreringar gjordes under denna studie blev av flera olika anledningar få, 18 dagar. Klimatet utomhus under studien registrerat som globtemperatur varierade från 22,4 till 34,7ºC. Då djurskyddslagen skall främja djurens hälsa och djurets naturliga beteende fick en grupp 126 höglakterande kor möjlighet att välja uppehållsplats under tiden 26 juli till 11 augusti. 2004. Korna fördes ut på betet vid niotiden på förmiddagen och var därefter fria att gå in och ur stallet efter egen vilja tills de togs in för kvällsmjölkning omkring klockan tre påeftermiddagen.

Kompaktaggregat är ett integrerat FTX- och FVP-system som används i passivhus. Vi har gjortenergiberäkningar i programmet VIP+ för att se hur kompaktaggregatet skulle kunna fungera ipassivhus i Sverige.De resultat vi har fått fram ur VIP+ visar att passivhus med ett installerat kompaktaggregat klararav att nå passivhuskraven ända upp till Skellefteå. De beräknade värdena understiger kraven förpassivhus, men en viss marginal behövs för att kraven ska nås även efter uppförandet avbyggnaden. Vi har även tolkat tekniska uppgifter på ett sätt som enligt oss har en positiv effektför passivhus på kallare orter. Därför tror vi inte att värdena för de tre nordligaste platserna ärhelt tillförlitliga.

The purpose of this thesis for Sapa Heat Transfer is to examine a furnace in which aluminium is pre-heated before hot rolling. The project is modeled in a computer environment in which the air flow in the furnace and the heat transfer to the aluminium solids are included. The computer environment and its governing equations, as well as boundary conditions and generalizations, are presented and explained.The simulations are based on two models. The first model has an asymmetric solid placement, which is how it looks in today's ovens. It is validated against collected data.

Kompaktaggregat är ett integrerat FTX- och FVP-system som används i passivhus. Vi har gjortenergiberäkningar i programmet VIP+ för att se hur kompaktaggregatet skulle kunna fungera ipassivhus i Sverige.De resultat vi har fått fram ur VIP+ visar att passivhus med ett installerat kompaktaggregat klararav att nå passivhuskraven ända upp till Skellefteå. De beräknade värdena understiger kraven förpassivhus, men en viss marginal behövs för att kraven ska nås även efter uppförandet avbyggnaden. Vi har även tolkat tekniska uppgifter på ett sätt som enligt oss har en positiv effektför passivhus på kallare orter. Därför tror vi inte att värdena för de tre nordligaste platserna ärhelt tillförlitliga.

Storage of biomass is often associated with problems such as heat development, dry matter losses and reduction of fuel quality. The rise in temperature can potentially cause a risk of self-ignition in the fuel storage. Moreover, emissions from storage piles can cause health problems in the surrounding. The dry matter losses and reduction of fuel quality can have economical effects. The aim of this thesis project is to develop guidelines on how to store large amount of biomass at Vattenfalls heat and power plants in an optimal way.

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.

This thesis calculates and compares the values of improved environmental quality due to future possible investment alternatives in biogas production facilities at Käppalaförbundets Reningsverk (Käppala Sewage Treatment Works) in an attempt to determine which alternative yields the highest such value. Käppala faces three investment alternatives for the usage of biogas. The alternatives are production of vehicle fuel, district heating and thirdly, heat and power production. Estimates of the value of environmental change are calculated for each of the three investment alternatives, and these estimates are then compared. The environmental change in question is the change in discharge levels of carbon dioxide (CO2), nitrogen oxides (NOx), sulphur dioxide (SO2) and particle matter.

A new build in the Swedish nuclear power system would entail increased re-quirements for the proposed repository, which is adapted after the reactors of today. With a fast reactor, capable of burning nuclear waste, operating in parallel with the light water reactors, the increased requirements on the repository could be reduced.In this thesis, simulations of a light water reactor and a fast reactor have been performed by using the Monte Carlo code Serpent to investigate the changes in the fuel inventory. The light water reactor in the study is a boiling water reactor and the fast reactor of the type sodium-cooled fast reactor and they have been used for three different operation scenarios.By studying the fuel composition and the results from the simulations of the three scenarios conclusions can be drawn. Conclusions regarding the change of the fuel inventory and decay heat in Clab as well as the interim storage facility and in the repository. Depending on the operation alternative the changes dif-fered significantly and especially regarding the mass of burned actinides for different fuels in the fast reactor.The lowest increase of fuel assemblies was meet when using 50 years old fuel with 20MWd/kg U burnout and 2,0 % enrichment for start up of the fast reactor and 30 years old fuel assemblies with 50MWd/kg U burnout and 4,7 % enrichment for the further operation of the reactor.The increase of the number of fuel assemblies was 3174, which is equivalent to 641tons of heavy metal.

The number of data centers and their capacity is increasing throughout the world. Theenergy used in these data centers and the emissions from the use are increasing at thesame rate. The total use of energy will double from 2008 to 2011 based on the trends indata centers use. Research in this area says that the emissions from data centers willhave surpassed the level of airline traffic in 2020. The index used today to compare howefficient a data center is, called PUE, is lacking some information.

Gunsta is situated about 10 km east of Uppsala. Today there are plans to establish 1000 new households in Gunsta before year 2030. The required energy for heating houses and water would be distributed via a district heating system, which also includes 200 existing residences. The annual required energy, according to this study, would be 16.2 GWh with a maximal peak effect of 6.9 MW. To meet this need, the study suggests a system with heat pumps to upgrade the 31?C water from a 1.8 kilometre deep borehole.

A problem in the field of district heating is the oil burners needed to provide power when a peak load occurs. One possible way of reducing the needed amount of oil is to reduce the power demand for space heating in the district-heating substations when the need for district heating water exceeds a certain limit. This can be done by use of a locally working controller function.In this Thesis the options concerning load priority are evaluated. To evaluate the potential for using controller functions concerning peak load priority an experiment was brought out in a chosen district-heating substation. The impact on the indoor thermal comfort during a heat reduction was also taken into account.

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.