This thesis examines different methods for the cooling of data centers. Several means of cooling with the refrigeration cycle have been studied, as well as the feasibility of using free cooling in different parts of Sweden. In addition, the possibilities of transferring excess heat to a nearby district heating system were investigated. It was found that in all investigated cases except two, the data center could be cooled solely with free cooling for at least 300 days a year when only the outside air temperature was considered as a constraining factor. The limit was then set to 20 °C.The vast majority of all district heating systems in Sweden get little to none of their heat from other excess heat sources.

The constant need of energy is something that affects us all no matter our current situation. Whether we are driving our car to work, taking the elevator or using the oven to cook dinner we end up relying on energy. Our whole society is continuously striving to achieve a higher grade of efficiency and the process of supplying ourselves with energy is no exception. The importance of appliances in our everyday life cannot be exaggerated and thus the importance of their high efficiency.Efficiency is already a keyword in the appliance industry with labels, stars and numbers helping us choosing the most suitable option for the task ahead. No matter how efficient appliances often use pure electricity as their energy source.

Industries with energy costs as a large proportion of their total costs are greatly affected by the instruments deployed to cope with the Swedish climate and energy policy goals. With energy costs representing more than 30 % of the total costs, tomato cultivators are one of the affected industries. In order to remain competitive with other countries, a more resource- and cost-efficient cultivation of tomatoes in greenhouses is desirable in Sweden. Based on the concept of industrial symbiosis, this study investigates the prerequisites for a resource-efficient production of locally grown tomatoes in Sweden through the utilization of low grade industrial waste heat. The study is based on the foundry industry as the supplier of waste heat.To investigate the environmental, technical and economic potential of the exchange of waste heat, a comparative life cycle assessment, an inventory of the supply of industrial waste heat in Sweden, a compilation of potential technologies for the recovery of low grade industrial waste heat for heating greenhouses and a comparative life-cycle cost calculation were carried out.

This Master degree project has been performed at the Braviken paper mill on papermachine 53 (PM53) which produces newsprint paper. The current economic situationhas contributed to declining demand for newsprint, which means it is extra important tobe competitive by high energy efficiency. Particularly as energy prices are expected torise when the economic growth returns.One way to increase energy efficiency is by reducing the water use in paper and pulpmills and consequently save energy through reduced heating of water. The thesis's maintask is to evaluate whether a water purification plant (microflotation plant) forpurification of process water in PM 53 is profitable. The microflotation plant enablesreuse of warm process water instead of losing the energy to receiving waters.

Hemp is an annual energy crop that fits very well in Swedish crop rotations. It is an interesting crop with many benefits, for example its ability to establish a large quantity of biomass in one year. Hemp is easy to grow and out-competes unwanted weeds through its aggressive growth pattern without the need for pesticides. Interest in growing hemp and other energy crops is currently decreasing, apparently because of high grain prices. These high prices give a higher net profit that we believe could partly cover the cost of hemp cultivation, while the hemp in turn would improve the crop rotation and thus repay its debts in the form of increased yields of other crops. The great disadvantage of hemp is the lack of knowledge about spring harvest of the crop.

District heating covers around 80 % of the heating demand in apartment buildings and 10 % in single-family homes in Sweden. In the year 2010 the total input of energy to the Swedish district heating grids was about 70 TWh, which corresponds to 11 % of the total energy input to the whole energy system in the country. Through the combined production of heat and power the CHP-plants often reaches an efficiency of 90 % from energy in the fuel to produced heat and power. In order to keep the efficiency high it is important for the owners of the plant to have good knowledge about the plants performance at different operation points. Strängnäs Energi AB initiated this diploma work together with FVB Sverige ab in order to come up with a program for short term planning of the production of heat and power at the company´s CHP-plant.The work consists of three main parts.

pelago. There is an old inn that is located on the island that has become a very popular attraction in the last couple of years. The inn has both a well-known restaurant as well as conference facilities that are used by tourists as well as the people of Stockholm over the summer months. The inn was built 1908 and has since remained in the same condition.make islands in the archipelago more environmentally friendly and promote sustainability. One of their project islands is Grinda.

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.

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.

People in today?s society are becoming more and more aware of how important it is to use energy as efficiently as possible. This is clearly noticeable by an increase in home produced heat with e.g. solar panels or heat pumps heating systems. These changing customer demands forces district heating technology to be redesigned, which is why there is an ongoing research regarding the next generation of district heating - low temperature district heating (LTDH).

In this Thesis the possibilities of designing a larger building that is very energy efficient in the sense that it would not need a conventional heating system are discussed. Solar radiation transmitted through the windows, internal heat from occupants, lamps and electric appliances inside the building and heat recovered from the ventilation system then have to be sufficient for the heating of the building. This study is of general interest since the property company, Akademiska Hus, plans to use this study as a first step in determining if this technique could be used in the future and thus be worth further investments. A building without a conventional heating system of the size investigated in this project has not yet been built.The energy needed for the heating of the building was simulated using VIP+.The conclusions from the study are that it is possible to build large buildings without any conventional heating system. This could be achieved in many different ways, for example by lowering the inside temperature or by using better windows and heat recovery system with higher efficiency.

Design of a house requires knowledge of both technology and economics. Heating and ventilation shall be designed, costs are calculated and estimated and requirements must be fulfilled. Which heating system is to be elected is also a difficult choice, especially with rising energy prices as a factor.The choice of energy system is not always given, because it depends on several factors. Below is a comparison between district heating, geothermal heat pump and electric boiler from an economic standpoint. In a previous report appears district heating and geothermal heat pump as the best options.

The purpose of this bachelor´s report is to expand the knowledge about heat supply of a small house in Malmö. The heat supply will be provided from solar panels in combination to two accumulator tanks which will storage the up heated water and a pellet boiler.The technique used here is warmth storage in water over seasons, which will provide the total need of heating for the house. Accumulator tanks in combination to solar panels gets more and more common in Sweden but this far it´s unusual to use it for storage over seasons. This report will highlight many of the difficulties associated whit heat storage and give information about a system's possible design and function.The design of this system is decided early on. An accumulator tank is placed 2 meters down in the earth on the backside of the house.

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.

Considering that the price and demand for energy gradually has risen over the past decade and a wider discussion about the human impact on the environment has become increasingly more important and given a clearer role in modern society. This has contributed to increased incentives to reduce the use of fossil fuels and increase the use of renewable energy.The agriculture currently accounts for 20 % of Sweden's total greenhouse gas emissions. A way for an agricultural company like Wapnö AB to reduce their emissions could be to utilize existing renewable energy sources within their own premises.The report's aim is to create an energy audit of Wapnö?s existing energy system and how it changes with a future biogas plant in operation. The energy audit is used to illustrate how the company?s climate footprint could change.