The Borehole heat exchangers of today suffer from poor thermal and hydrodynamic performance. The purpose of this thesis is to improve the performance of ground source heat pump systems and thermal energy storages by increasing the energy efficiency of the Borehole heat exchangers. For this reason, the annular coaxial Borehole heat exchanger (CBHE) has been analyzed. This type of heat exchanger is interesting in terms of both thermal and hydrodynamic performance. A model has been set up in the program Comsol Multiphysics in order to investigate the heat transfer characteristics along the Borehole.

The thermal response of a Borehole field is often described by non?dimensional response factors called gfunctions.The g?function was firstly generated as a numerical solution based on SBM (Superposition BoreholeModel). An analytical approach, the FLS (Finite Line Source), is also accepted for generating the g?function. In thiswork the potential to numerically produce g?functions is studied for circular Borehole fields using the commercialsoftware COMSOL.

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.

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.

Increased resource efficiency in an energy system could result in large economic and environmental benefits. Tekniska verken i Linköping AB (Tekniska verken) is responsible for the district heating network in Linköping. Their vision is to create the world?s most resource efficient region. An important step towards this vision is more efficient usage of produced heat, something which could be achieved through integration of a seasonal heat storage in the energy system.

The objective of this study is to examine the sustainability of recovering industrial wasteheat from several heat sources in a foundry constructed in a plant belonging to ITT Waterand Wastewater in Emmaboda, Sweden. A triple bottom line perspective will be appliedto achieve this objective. The triple bottom line approach takes into account ecologicaland social performance in addition to financial performance. The technology forrecovering the waste heat is a Borehole Thermal Energy Storage (BTES) which is aconstruction consisting of 140 vertical Boreholes, 150 meters deep with an internal spaceof four meters.The calculated amount of energy for storage is approximately 3800 MWh annually. Ofthis amount 2500 MWh are expected to be utilized, while storage losses accounts for theremaining part.

Estimation of the variation in the integrated hydraulic conductivity around the Tunåsen infiltration facility - An investigation of the effects of uncertainties in existing informationAlmost half of Sweden?s drinking water volume is produced from groundwater. The main fraction of this is extracted from eskers, some of which allow for very large extraction rates. Despite this, the groundwater volume is not sufficient in some areas. This has led to an extensive use of artificial recharge.In Uppsala, the total volume added through artificial recharge is divided between four infiltration facilities.

During installation and operation of a geothermal heat pump system leakage of an antifreezing agent can appear in a Borehole and leak out in surrounding groundwater. To guarantee high quality drinking water for generations to come Sweden has dedicated some areas as water protection areas. The local authority gives permits for the installation of heat pump systems within water protection areas. Before giving a permit the local authority makes an evaluation of the risks involved in installation and operation of the system within the area. By keeping a certain distance between the protected object in the area and the heat pump system the risk of polluting the protected object with an anti-freezing agent can be reduced.This thesis makes a comparison between three different methods of calculating an appropriate distance between the protected object and the heat pump system.

An increasing number of heat pump producers have developed heat pumps that can be connected to solar panels. In this thesis we have examined the possibilities of connecting solar panels to existing ground source- and geothermal heat pumps that has not been adapted to solar panels. During the work process, a prototype plant has been built to compare our theory with the practical results and with our designed sizing tool. The work has rendered in knowledge that will be used to build a sun module that can be easily connect to the existing heat pump system. The existing heat pump, our test plant, has been supplemented by an advanced storage tank used to allow different operating modes.

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.

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.

Humanity stands before a huge challenge to lower its emissions of carbon dioxide and its use of energy at the same time as the global population is rising and the developing countries are being industrialized. A lot of newly built buildings are due to this challenge, designed to be more energy efficient but also use renewable energy resources instead of pollutant fossil fuels .Solar energy is one of the purest forms of energy that exists in abundant amounts, which is why it is most likely that it could come to play a major part in the future energy market. The main purpose of this report is to investigate the possibility to implement a sustainable energy system with solar thermal heat and  heat storage as main sources of energy in the neighborhood ?kvarteret Lagern?, which is the area where the old football stadium ?Rasunda Stadion? was located. New developments within different heat storage techniques have opened up new approaches to enable buildings an all year round heat supply from solar energy. This report will focus on heat storage in Boreholes. At the present here is only a preliminary plan of how the neighborhood is supposed to be designed.

For Skattkärr IF a turf field with warming has been projected to increase field?s utilization hours and to have a longer period for athletes to perform their activities outdoors. The technique chosen to heat the plan is a type of a geothermal heating system without a heat pump. The brine, which is water with 30% ethanol, collects heat from the Borehole and discharges it to a coil in the field. There is at position 11 Boreholes but it is planned to increase the number to 31, which is the design for the facility.

Sverige har en hög andel installerade bergvärmepumpar, som är en typ av vätska-vatten värmepump. Ett problem som finns för befintliga bergvärmesystem är att berget med tiden kyls ned då returslangen till borrhålet konstant levererar kyla till berget. Till följd av detta mister systemet en betydande del av sin verkningsgrad samtidigt som det i extrema fall kan leda till permanent isbildning i borrhålet.Ett sätt att motverka detta problem är att tillämpa termisk energilagring i bergvärmesystemets borrhål. Den internationella benämningen för denna teknik är ?Borehole Thermal Energy Storage, BTES?.Rapporten har behandlat en friliggande enplansvilla med ett befintligt bergvärmesystem som tillämpar termisk energilagring i bergvärmesystemets borrhål med solvärme.

Syftet med rapporten är att göra en jämförelse av två olika metoder för att kyla ett fiktivt kontorshus som är 2 000 m² stort och beläget i Västerås. För att representera ett normalt kontorshus har kyleffektbehovet valts till 50 W/m² vilket ger totala kyleffektbehovet 100 kW. I ena fallet finns en kylmaskin som kyler byggnaden och i andra byts kylmaskinen mot ett antal borrhål som motsvarar hela kyleffekten. För att kunna bedöma de tekniker som har använts har energianvändning och växthuspotential beräknats i ett livscykelperspektiv. Denna energianvändning beräknas som inbäddad energi, vilket är all energi som använts från framtagande av råmaterialen till färdiginstallerat system.