The fast development in electronics has resulted in faster and faster computers. Furthermore, the electronic components trend to get smaller and smaller by the year. With more processing power combined with smaller components the heat generation rapidly increases. The scope of this study is to examine a spot cooling technique consisting with different geometry of multiple impinging jets in combination with a cross-flow by the use of CFD. The case is limited to a heated wall mounted cube cooled by a impinging jet as well as an multiple impinging jets in a low velocity cross-flow. This study can be divided into two parts a verification study and a detailed study. The verification study consist of comparison between RSM model and measured values for both the turbulent flow and the surface temperature. The single impinging mesh consists of 934 k elements while the plus 1439 k and cross consists of 2809 k elements. All the meshes are created in ANSYS fluent and this paper contains a detailed guide to create them. The verification study proved that RSM can predict the complicated flow with good agreement with the single impinging jet. The heat transfer coefficient differ substantially between the cases. The PIV compared to the UDF for the inlet velocity profiles had a 21\% increase in heat transfer coefficient in the top layer of the cube. In all the simulations the cross had at least an increase of 18\% on average \(h\). While there was no real verification study for the multiple impinging jets I would still argue that cross is better than the plus sign geometry in terms of heat transfer.

The aim of this project is to evaluate the possibility to integrate, in terms of energy, the future Nya Studenternas IP and Uppsala University Hospital. The focus is on integration of thermal energy solutions. To cover the cooling demand a seasonal snow storage and the use of cooling machines is studied. For the heat demand a joint heat storage is investigated which is heated partly with the excess heat from cooling machines. The environmental impact in terms of CO2 emissions is investigated. A conclusion drawn from the project is that the use of district heating and cooling of Nya Studenternas IP and the Uppsala University Hospital could be reduced in several ways by integrating the energy systems of the two facilities. For instance, with the support of a seasonal snow storage and cooling machines for cooling, and heat obtained from the cooling machines for heating, the emissions of CO2 could be reduced with 36% based on a Nordic electricity mixture. Out of the suggested integrated energy solutions the most efficient when it comes to reducing CO2 emissions is cooling and heating through cooling machines with a capacity of reducing the CO2 emissions of 20.6 %.

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The thesis performed in this research is focused on a particular type of energy system, energy systems in supermarkets. As supermarkets are high-energy using buildings, their energy system optimization has been investigated in recent years, with the main focus in the refrigeration system, which can take up to 50% of the total energy of the supermarket. However, the complexity and interconnections of the different systems increase the difficulty of the task. The aim of this work is to contribute in SuperSmart project, an EU project which main objective is to reduce the impact of the supermarket sector overall Europe, through the development of an ecolabel criteria. To simulate the energy use in supermarkets, CyberMart software is bring forward. This tool is used both to determine the parameters which have a higher impact in the supermarket energy system and perform energy representation based on those parameters. Finally, the design of the most energy efficient store is also presented. According to CyberMart, some of the most determinant parameters in the supermarket energy system are refrigeration capacities, plug in cabinets used, lights power, heating system technologies used and whether the cabinets are covered or not. Using some of these parameters plus other important characteristics from the store, two energy representations are performed. Whereas the quadratic representation provides the final results concerning heat or electricity demands with a high accuracy, the linear representation presents the increase or decrease of kWh per each parameter, enabling supermarkets owners to compare different parameters within the global system. It is concluded from these representations, which distinguish between heat recovery and floating condensing technologies, that the most important parameters in the global system are the temperature inside at winter and the refrigeration capacity. However, some unreasonable events appear, like the decline of electricity demand when the height of the building increases or the drop of heat demand with the rise of opening hours. These facts occur due to the high complexity of the global system, implying different connections between the sub-systems within CyberMart. Concerning the most energy efficient store located in Stockholm, the obtained results show the most energy efficient supermarket is composed by CO2 refrigeration and heating systems, and a R410_A air conditioning system. The optimal electricity use of each establishment size from large to small area is 382, 394, 390 and 281 kWh/m2*year respectively, with the highest values obtained in Supermarkets and Discount stores, due to their higher rate of refrigeration power per store area. Keywords: Supermarket, refrigeration system, SuperSmart, CyberMart, heating system, refrigeration capacity, plug in cabinets, lights power, heating system technology, covering of the cabinets, energy representation, heat recovery technology, floating condensing technology, air conditioning system, Discount store.

The study focuses on the possible positive impacts derived from implementing innovative energy solutions to the Åland energy system by 2030. Four scenarios are formulated in order to determine feasible solutions in economic and technological terms. At the present most of the energy supply relies on the power exchange with mainland by subsea interconnections. The archipelago’s main challenge is to reduce the high dependence from the main importer (Sweden) by increasing the use of local renewable energy sources. Wind power results to be the most favorable form of variable renewable energy (VRE) available. “Behind the meter” photovoltaic (PV) rooftop solar panels, biomass combined heat and power (CHP) generation and a Li-ion battery system are considered as supportive solutions to wind power. The simulations made with RetScreen and EnergyPLAN confirm that solar power and a battery system can only have a modest role compared to wind power. A final economic analysis assesses the revenue projections for the new technologies implemented. The results indicate a very positive investment potential for the new wind farms, coupled with a proper Li-ion battery solution. Additionally, the thesis investigates the best options for solving frequency and voltage imbalances, appearing after the implementation of intermittent energy sources. A flywheel technology has been included in the scenarios in order to enhance the primary frequency control of the whole system.

This paper presents an analysis of the feasibility of utilizing a hybrid renewable energy system to supply the energy demand of a milk and meat farm in Cuba. The study performs simulation and optimization to obtain a system design of a hybrid renewable energy system for application on the farm Desembarco del Granma in the Villa Clara province in the central part of Cuba, for three different cases of biomass availability. The energy resources considered are solar PV, biogas, and wind. A field study is carried out to evaluate the energy load and the biomass resource available for biogas production of the farm Desembarco del Granma, and the feasibility of biogas electrification is evaluated for the three different scenarios of biomass availability. The field study methodology includes semi structured interviews and participant observation for information collection. The farm Desembrero del Granma is estimated to have a scaled annual average electrical load of 264 kWh/day with peak load 26.34 kW, while the scaled annual average deferrable load of the farm was estimated to be 76 kWh/day with a peak load 16 kW. The thermal load was find to consist primarily of energy for water heating and cooking. The thermal demand for cooking was estimate to be 4.5 kWh per day, while the thermal load for water heating was not estimated. The thermal energy need for water heating is assumed to be provided for by solar thermal energy, and is not included in the energy system models of this study. For the modeling, the thermal demand for cooking is assumed to be provided by combustion of biogas. System simulation and optimization in regard to energy efficiency, economic viability and environmental impact is carried out by applying the Hybrid Optimization Model for Electric Renewables (HOMER) simulation and optimization software tool. For two of the biomass scenarios, the optimized energy systems received in HOMER were identical; hence only two biomass scenarios were analyzed. The first one represents the current biomass collected and the biogas production capacity of the farm (including the one not yet utilized), and the second one represents the amount of biomass available if the animals would be gathered in the same place all of the time. A PV-wind hybrid energy system with 100 kW PV installed capacity, 30 kW wind power installed capacity consisting of 10 wind turbines of the size 3 kW, a battery bank of 100 batteries (83.4 Ah/24 V), and a 100 kW inverter is considered the most feasible solution for the current biomass scenario. For the increased biomass scenario, a PV-biogas hybrid energy system configuration of 5 kW PV installed capacity, a 60 kW biogas generator, and an inverter of the size 10 kW is considered the most feasible option. Biogas electrification is shown to not be economically feasible for the current biomass scenario during the conditions modeled in this study, but for the increased biomass scenario biogas electrification was shown to be a feasible option. If the farm would build more biodigestors, biogas electrification could thereby be effective from a financial point of view.

Historically, domestic tasks such as preparing food and washing and drying clothes and dishes were done by hand. In a modern home many of these chores are taken care of by machines such as washing machines, dishwashers and tumble dryers. When the first such machines came on the market customers were happy that they worked at all! Today, the costs of electricity and customers’ environmental awareness are high, so features such as low electricity, water and detergent use strongly influence which household machine the customer will buy. One way to achieve lower electricity usage for the tumble dryer and the dishwasher is to add a heat pump system. The function of a heat pump system is to extract heat from a lower temperature source (heat source) and reject it to a higher temperature sink (heat sink) at a higher temperature level. Heat pump systems have been used for a long time in refrigerators and freezers, and that industry has driven the development of small, high quality, low price heat pump components. The low price of good quality heat pump components, along with an increased willingness to pay extra for lower electricity usage and environmental impact, make it possible to introduce heat pump systems in other household products. However, there is a high risk of failure with new features. A number of household manufacturers no longer exist because they introduced poorly implemented new features, which resulted in low quality and product performance. A manufacturer must predict whether the future value of a feature is high enough for the customer chain to pay for it. The challenge for the manufacturer is to develop and produce a high-performance heat pump feature in a household product with high quality, predict future willingness to pay for it, and launch it at the right moment in order to succeed. Tumble dryers with heat pump systems have been on the market since 2000. Paper I reports on the development of a transient simulation model of a commercial heat pump tumble dryer. The measured and simulated results were compared with good similarity. The influence of the size of the compressor and the condenser was investigated using the validated simulation model. The results from the simulation model show that increasing the cylinder volume of the compressor by 50% decreases the drying time by 14% without using more electricity.  Paper II is a concept study of adding a heat pump system to a dishwasher in order to decrease the total electricity usage. The dishwasher, dishware and water are heated by the condenser, and the evaporator absorbs the heat from a water tank. The majority of the heat transfer to the evaporator occurs when ice is generated in the water tank. An experimental setup and a transient simulation model of a heat pump dishwasher were developed. The simulation results show a 24% reduction in electricity use compared to a conventional dishwasher heated with an electric element. The simulation model was based on an experimental setup that was not optimised. During the study it became apparent that it is possible to decrease electricity usage even more with the next experimental setup.

In recent years, there has been significant pressure to reduce greenhouse gas emissions, to achieve higher efficiency and to integrate greater amounts of renewable energy resources in energy system. Governments at all levels have recognized the environmental impacts of the energy sector, as well as the ways in which this sector is closely-linked to a range of economic issues (e.g., industrial development, inflationary prices and local economic development). In general, every effort has been made to cope with the challenges in providing a sustainable energy solution for achieving the goals. Even though the concept of “Smart Grid” has recently been highlighted in the electricity sector to improve efficiency of energy use and to reduce greenhouse gases to achieve business goals, the driving initiatives for generating a Smart Grid are straightforward and its scope and functions differ from a Smart Energy Network (SEN) which has a broader boundary and more components. A comprehensive concept of SEN beyond Smart Grid is presented to effectively integrate energy systems which can not only cover available energy resources but also address sustainability issues. The availability of new technologies for utilizing the renewable energy such as solar, wind and biomass, and reducing the carbon footprint of fossil fuels by including natural gas within an integrated energy network provides a base for better conservation of energy usage and providing a cleaner environment. Moreover, the new energy carriers such as hydrogen and sustainable natural gas integrated into cogeneration systems should be taken into account when such a network is developed. A cogeneration system is a promising solution for effectively supplying energy to district consumers for high density urban environment. In this thesis, a new community-scale cogeneration system is modeled using TRNSYS (Transient System Simulation) software, which enables analysis of transient characteristics of cogeneration and to investigate critical factors which should be considered for successful integration into a SEN. This thesis focuses on defining what a Smart Energy Network is, its functions and the critical criteria of demonstrating and validating this concept, and developing a model for cogeneration system according to the concept of Smart Energy Network.

All jurisdictions have an energy system consisting of processes responsible for the conversion and transportation of supplies of energy from various sources to meet the end-use energy demands. Energy systems are dynamic as they respond to uncertainties such as higher energy costs, new energy technologies, public concern over the environmental impacts of energy production, evolving consumption patterns, and the aging of existing infrastructure; these changes can affect the energy suppliers, the end users, and those responsible for operating the energy system. To reduce possible adverse effects and improve the energy security of the system, energy policies are often designed by those responsible for the processes. However, changes to the energy policies can also impact the system’s energy security. Therefore, it is critical to study the possible effects of changing energy policies before they are deployed. To address this problem, a visualization tool has been developed to represent a jurisdiction’s energy system. The tool allows the effects of changing energy policies on energy security to be analysed. A case study using real-time wind data from the City of Summerside has been implemented to demonstrate the capabilities of the tool. This presentation will elaborate on the methods and implementation of the visualization tool and explain the results obtained from the analysis of the Summerside project.

In recent years, there has been significant pressure to reduce greenhouse gas emissions, to achieve higher efficiency and to integrate greater amounts of renewable energy resources in energy system. Governments at all levels have recognized the environmental impacts of the energy sector, as well as the ways in which this sector is closely-linked to a range of economic issues (e.g., industrial development, inflationary prices and local economic development). In general, every effort has been made to cope with the challenges in providing a sustainable energy solution for achieving the goals. Even though the concept of “Smart Grid” has recently been highlighted in the electricity sector to improve efficiency of energy use and to reduce greenhouse gases to achieve business goals, the driving initiatives for generating a Smart Grid are straightforward and its scope and functions differ from a Smart Energy Network (SEN) which has a broader boundary and more components. A comprehensive concept of SEN beyond Smart Grid is presented to effectively integrate energy systems which can not only cover available energy resources but also address sustainability issues. The availability of new technologies for utilizing the renewable energy such as solar, wind and biomass, and reducing the carbon footprint of fossil fuels by including natural gas within an integrated energy network provides a base for better conservation of energy usage and providing a cleaner environment. Moreover, the new energy carriers such as hydrogen and sustainable natural gas integrated into cogeneration systems should be taken into account when such a network is developed. A cogeneration system is a promising solution for effectively supplying energy to district consumers for high density urban environment. In this thesis, a new community-scale cogeneration system is modeled using TRNSYS (Transient System Simulation) software, which enables analysis of transient characteristics of cogeneration and to investigate critical factors which should be considered for successful integration into a SEN. This thesis focuses on defining what a Smart Energy Network is, its functions and the critical criteria of demonstrating and validating this concept, and developing a model for cogeneration system according to the concept of Smart Energy Network.