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  • 51.
    Dimtsu Tamene, Hailu
    Dalarna University, School of Technology and Business Studies, Energy Technology.
    Solar Mini-grid Model Validation for Rural Electrification2018Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    This thesis was aimed at validating an Excel tool developed by Energicity Company. In addition, to study a commercial software that can be used to design a solar mini-grid system for the company.

    A 9.9 kW solar mini-grid in Bekwai, Ghana was used as a case study. Weather data from Meteonorm and component specification was used as input parameter for the simulation works.

    HOMER pro and PVsyst commercial software were selected to validate the Excel tool. Each software was also explained in detail.

    The validation was done by comparing input parameters and simulation results of the Excel tool with the selected commercial software. The process was divided into two main parts. The first part was, comparing the mathematical model, and the PV array electricity production of the software used as an input to the Excel tool, which was SAM, with HOMER pro and PVsyst. The second part was comparing the final simulation result of both tools, including the Excel tool.

    The comparison result shows that the difference in the mathematical model for the diffuse irradiation in each software leads to a difference in the electricity production at the PV array output. Even though the difference is not significant for a small scale mini-grid system, the difference can cause a wrong estimation for critical loads, where a higher percentage of availability is required.

    The DC losses at the PV array has a notable impact on estimating the electricity production. PVsyst considers more loss parameters than SAM and HOMER pro. As a result, the simulation result of the PVsyst shows lower electricity production at the output of the PV array compared to the others. This indicates as PVsyst is a more conservative software model.

    The loss in the battery has another significant impact on estimating the energy delivered to the load. The battery model for each tool was different. The Excel tool uses higher battery loss percentage. Due to this, the energy served to the load by the Excel tool was lower than HOMER pro and SAM. HOMER pro’s estimation of the battery loss was almost equal to the Excel tool. The battery loss estimated by PVsyst was lower than all models. However, there were uncertainties in the input parameters of the battery, because of most of the parameters provided by the battery manufacturer was not compatible with the input parameters required by PVsyst.

  • 52. Dipasquale, Chiara
    et al.
    Fedrizzi, Roberto
    Bellini, Alessandro
    Gustafsson, Marcus
    Ochs, Fabian
    Bales, Chris
    Dalarna University, School of Technology and Business Studies, Energy Technology.
    Database of energy, environmental and economic indicators of renovation packages for European residential buildings2019In: Energy and Buildings, ISSN 0378-7788, E-ISSN 1872-6178, Vol. 203, article id 109427Article in journal (Refereed)
    Abstract [en]

    Increasing the energy efficiency with a vast impact in the residential building stock requires retrofit solutions that can be exploited with respect to a wide range of different building typologies and climates. Several tools and methodologies are nowadays available both for the assessment of building demands and for the individuation of optimum retrofit solutions. However, they are usually either too complex to be adopted by professionals or, on the contrary, oversimplified to account for the full complexity of a deep envelope and HVAC system retrofit. In this context, this paper describes a methodology developed to generate reliable information on retrofit solutions for typical buildings in different climatic conditions. Detailed numerical models are used to simulate a number of combinations of envelope and HVAC systems retrofit measures and renewable energy integration. Energy performance results are gathered in a database that allows comparing solutions, spanning over a range of more than 250,000 combinations of building types, age of construction, climates, envelope performance levels and HVAC systems configurations. Economic feasibility is also derived for each of the combinations. In this way, the accurateness of a detailed and validated calculation is made available to assist during the decision making process, with minimum computational effort being required by professionals: the variety and density of evaluated combinations allows to easily assess the performance of a specific case by interpolating among instances previously assessed. The applicability of the results to different climates and similar building typologies is verified by a comparison of the database results with a specific case dynamic simulation.

  • 53.
    Diyad Elmi, Mohamed
    et al.
    Dalarna University, School of Technology and Business Studies, Energy Technology.
    Manoharan, Lavaraj
    Dalarna University, School of Technology and Business Studies, Energy Technology.
    Optimal Grid Connected Inverter Sizing for Different Climatic Zones2019Independent thesis Advanced level (degree of Master (One Year)), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Grid connected inverter requires accurate and appropriate sizing which depends on the temperature, inverter operating efficiency, performance ratio, annual system yield and solar radiation characteristics. The aim of this study was to design and size for optimum sizing factor for grid connected inverter. The main component to be considered in any photovoltaic grid connected system is the inverter since the output depends on the inverter sizing ratio, therefore optimal sizing factor was designed by considering factors that affects inverter sizing such as temperature, irradiance and the location. Large and small systems of 50 kW and 5 kW respectively were considered to determine grid connected inverter sizing factors for different climates in Kenya, Sweden, and India using PVsyst simulation. Two different inverter brands of SMA and ABB with 20 kW and 25 kW rating for large system and 4.6 kW, 4 kW inverters for small system.

    PVsyst simulation result showed that different locations with different orientation angles, the optimum sizing varies hence affects the annual performance of the system. Photovoltaic system inverters are sized based on the rated power of the installed system and this can be achieved when the inverter size is either almost matching or not.

    In this case the study presents the optimal sizing factor for grid connected inverter for Mandera in Kenya, Norrköping in Sweden and Kerala in India. The determination was done through the use of designing, assessing and analyzing of the relationship between the sizing factor with performance ratio, operational efficiency and annual hourly energy yield. The unique weather profile in Kerala and in Mandera favors the adoption of solar energy technology in the location. Solar radiation for one year was used as a baseline input and the result reveals that Mandera receives yearly radiation of 2.1 MWh/m² while Kerala and Norrköping receives 2 MWh/m² and 1.1 MWh/m² respectively.

    Design simulation using PVsyst tool made it possible for the determination of the optimal sizing factor for the grid connected system. Considerations such as the losses and the variations within the specific location was done and a graph showing the relationship between the sizing factor in relation to the operational inverter efficiency as well as energy yield and performance ratio was later on compared to see the behavior of the sizing factor.

    The study concludes that operational efficiency, performance ratio and energy yield affects the array optimum sizing ratio. For the three locations, inverters (SMA and ABB) shows different variations because optimal sizing ratio depends on the location and irradiation. The results reveal that Mandera has an optimal grid connected inverter sizing of the range from 1.1 to 1.4 while in Kerala it has from 1.2 to 1.4 and Norrköping has the range from 1.1 to 1.3. Optimal sizing of grid connected inverters depends on the energy yield and the location therefore the inverter mismatch voltage and its rating values have to be considered while determining the optimal sizing factor. The 25 kW inverters in all the locations had better efficiency and sizing factor and this proves that sizing the photovoltaic inverter will give better performance and efficiency.

  • 54.
    Elbana, Karim
    Dalarna University, School of Technology and Business Studies, Energy Technology.
    Socio-Technical Analysis for the Off-Grid PV System at Mavuno Girls’ Secondary School in Tanzania2018Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    The aim of this study is to investigate, analyse and evaluate the installed off-grid PV system in Mavuno

    girls’ secondary school that is located in a rural area in northwest Tanzania. The original motivation behind this study was the rapid degradation of the installed battery bank within less than 3 years. The PV system was installed before the actual operation of the school, so the study aimed to answer a very pressing question which is "What is the actual load profiles in the school?". There was a high need to identify the actual school load profiles to enable several concerned social actors to evaluate the system and to decide for future extensions. Therefore, the study aimed to analyse the implementation of electricity in the school by creating actual load profiles, analysing the system performance versus the users’ needs and evaluating the sustainability and utilization of implementation.

    The study followed a multi-disciplinary approach combining the social and technical aspects of PV systems implementation

    to seek further understanding of the users’ consumption behaviours. It thus included a 1-month of field work in June 2018 during which participant observations and semi-structured interviews together with load measurements were carried out so as to create load profiles that are considering the patterns and deviations in users’ behaviours. During the field work, 2/3 of the students were in holidays so the taken measurements corresponded to the school at 30 % capacity. That is why the study also included 4 days of inverter data logging after the 1-month field work by the technical head of the school to overcome the limitations in held measurements.

    The observations showed that the actual installed system was slightly different from the documentation. In addition, the local installation practices are not fully appropriate from the technical point of view, and are affected by local social norms, as will be discussed. Besides, the participant observations and held interviews with relevant social actors showed that the daily behaviours of energy users do not exactly follow the school daily routine. Consequently, the social study was important to create actual effective load profiles. The observations and responses from interviews together with measurements were used to categorize the school loads into 29 different units. Those units can be used for current load prioritizations and for future load extrapolations. The created load profiles also represent a useful addition to load databases used by energy researchers who work on similar rural electrification projects.

    After the field work, several characteristics were calculated by Microsoft Excel such as apparent power consumptions, active power consumptions, battery bank state of charge, load power factor and PV generated energy. The characteristics were used in calculations evaluating the energy balance in the system. The results of held calculations showed that lighting during dark hours accounted for on around 78 % of the logged daily apparent energy use, as it has a low a low average power factor of 0.28. It also showed that some loads if time-bounded, they will significantly decrease the daily energy consumption. The calculations were also used to run PVSyst simulations to evaluate the system sizing which resulted in the recommendation that either the array size should be doubled, or the apparent energy consumption should be decreased to half.

    The study included suggestions for possible improvements such as decreasing the reactive consumed energy by either replacing the currently used light bulbs with ones that have higher power factor (

    ≥0.8 for example) or by installing a capacitive compensation for power factor correction. In addition, it was recommended to quantify the school loads according to their priority or importance and to regulate observed time-unbounded loads such as "pumping water" and "ironing". Lastly, the study discussed how generated electricity is utilized in the school and what opportunities for women empowerment have become potentially possible with the provision of electricity.

  • 55.
    ElSherif, Khaled
    Dalarna University, School of Technology and Business Studies, Energy Technology.
    Solar Powered Smart Street Post2018Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    This thesis work aimed to develop solar Photovoltaic (PV) powered smart street post. The post was set to serve on highways for wild animals’ detection and warn vehicles of possible crossings. The main aim was to design reliable standalone PV system via PVSyst software and experimenting four different PV technologies including a bifacial module under. Another aim was to select and develop the hardware and software terms of the smart street pot. Radar sensor and analog to digital (A/D) data acquisition (DAQ) card were set to be used for the motion detection. RF wireless communication module was used for communicating with nearby posts to send data and trigger warning light emitting diodes (LED) sign. A Raspberry Pi microcontroller was programmed to control the operation of the street post through processing the signal from radar sensor and communicating with nearby posts.

    The PV system design included generation of street post’s daily profile, sizing and selection of the components of the system including the module, battery, charge controller and power stage circuit. The later was designed to provide suitable voltage level and interface for the loads connected. PVSyst model was built and set to be located in Ulm, Germany. The design parameters were set, and different set of orientations were tested for each module.

    The simulation results showed bifacial module delivered a reliable PV system in case of south and south-east orientation and achieved better performance in other orientations in comparison to the other PV modules implemented. Due to limitations in PVSyst software the results provided had an overall uncertainty of 5%.

    The microcontroller was able to process the data from the radar sensor and DAQ card and perform fast Fourier transform (FFT). However, further processing of motion detection was complex to be included in the thesis work. The radar sensor and DAQ card provided signals with uncertainty of ± 3.4 mV. The RF wireless communication module transmitted signal over various ranges up to 150 m with time delay of 500 ms.

  • 56.
    Farag, Ahmed
    et al.
    Dalarna University, School of Technology and Business Studies, Energy Technology.
    Gabriele, Giovanni
    Dalarna University, School of Technology and Business Studies, Energy Technology.
    A Feasibility Study of Solar-Assisted District Heating in Torsång2018Independent thesis Advanced level (degree of Master (One Year)), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Nowadays, using renewable energy, especially solar, is an expanding trend in the Nordic

    countries. In the past few years, the Europian Union has issued energy efficiency directives

    [1] that obligated its member countries to involve 50 % of renewable energies in the

    district heating (DH) networks. This opens the door for the integration of solar energy in

    the existent heat generation plants.

    Borlänge Energi AB, a municipal energy company, owns and operates a DH plant and

    network in Torsång; a small-community village outside Borlänge, in Dalarna County,

    Sweden. The plant generates the required heat using conventional energy boilers fueled by

    wood pellets, grid electricity, and oil. The company suggested using the nearby empty land,

    owned by the municipality, for installing a solar thermal collector field.

    The thesis aims at doing a feasibility study of the possible integration of a solar thermal

    collector field to the existent DH plant in Torsång. The goal is to replace the oil boilers

    with solar energy and to estimate the amount of fuel and emissions that can be saved and

    their effects on economics.

    To achieve the appointed tasks, a planned strategy was developed. After visiting the site

    and collecting all relevant data, the missing hourly load was calculated. Thumb rules were

    used for system sizing. The Polysun simulation software is used to model and simulate the

    proposed system. Two collector models from the same manufacturer were tested. The

    effects of lowering the DH temperature and changing the pellet boiler shut-down period

    were investigated. A sensitivity analysis of the solar fraction was conducted to provide

    different sizing options. In the end, an economic evaluation of the proposed solutions was

    made.

    The results revealed that, for all cases, the oil boilers could be successfully replaced saving

    0.6 m3 of diesel oil and 1.1 ton of CO2 emissions annually. A solar fraction of around 35 %

    was achieved. Shutting down the pellet boiler in the three summer months was proposed

    which reduced its operating time. Consequently, the pellet boiler energy production and

    the fuel consumption reduced by around 36 %. While its CO2 emissions are mitigated by

    26 %.

    The project, from the economic perspective, is showing a competitive value of LCOH

    (between 386 and 423 SEK/MWh) which is lower than the actual cost of the produced

    heat by the plant (500 SEK/MWh). The payback period is quite reasonable with values

    between 24 and 37 years, depending on the chosen solution. Governmental subsidies are

    not taken into consideration in the economic analysis, so the proposed values represent an

    upper boundary, which can be lowered whenever any incentive will be granted to the

    project.

    The proposed system makes room for two possible solutions: the first allows to shut-down

    the pellet boiler for the whole summer, thus giving more flexibility for the maintenance of

    it, benefits in terms of fuel and related emissions saved, but increasing the electricity

    consumption. The second solution, instead, is offering a shorter shut-down time, but with

    more monetary benefits.

  • 57.
    Fedorov, Anton
    Dalarna University, School of Technology and Business Studies, Energy Technology.
    Photovoltaic System Design for a Contaminated Area in Falun – Comparison of South and East- West Layout2015Independent thesis Advanced level (degree of Master (Two Years)), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    In this thesis the solar part of a large grid-connected photovoltaic system design has been done. The main purpose was to size and optimize the system and to present figures helping to evaluate the prospective project rationality, which can potentially be constructed on a contaminated area in Falun. The methodology consisted in PV market study and component selection, site analysis and defining suitable area for solar installation; and system configuration optimization based on PVsyst simulations and Levelized Cost of Energy calculations.

    The procedure was mainly divided on two parts, preliminary and detailed sizing. In the first part the objective was complex, which included the investigation of the most profitable component combination and system optimization due to tilt and row distance. It was done by simulating systems with different components and orientations, which were sized for the same 100kW inverter in order to make a fair comparison. For each simulated result a simplified LCOE calculation procedure was applied. The main results of this part show that with the price of 0.43 €/Wp thin-film modules were the most cost effective solution for the case with a great advantage over crystalline type in terms of financial attractiveness.

    From the results of the preliminary study it was possible to select the optimal system configuration, which was used in the detailed sizing as a starting point. In this part the PVsyst simulations were run, which included full scale system design considering near shadings created by factory buildings. Additionally, more complex procedure of LCOE calculation has been used here considered insurances, maintenance, time value of money and possible cost reduction due to the system size.

    Two system options were proposed in final results; both cover the same area of 66000 m2. The first one represents an ordinary South faced design with 1.1 MW nominal power, which was optimized for the highest performance. According to PVsyst simulations, this system should produce 1108 MWh/year with the initial investment of 835,000 € and 0.056 €/kWh LCOE. The second option has an alternative East-West orientation, which allows to cover 80% of occupied ground and consequently have 6.6 MW PV nominal power. The system produces 5388 MWh/year costs about 4500,000 € and delivers electricity with the same price of 0.056 €/kWh. Even though the EW solution has 20% lower specific energy production, it benefits mainly from lower relative costs for inverters, mounting and annual maintenance expenses.

    After analyzing the performance results, among the two alternatives none of the systems showed a clear superiority so there was no optimal system proposed. Both, South and East-West solutions have own advantages and disadvantages in terms of energy production profile, configuration, installation and maintenance. Furthermore, the uncertainty due to cost figures assumptions restricted the results veracity.

  • 58. Fedrizzi, Roberto
    et al.
    Dipasquale, Chiara
    Bellini, Alessandro
    Gustafsson, Marcus
    Dalarna University, School of Technology and Business Studies, Energy Technology.
    Bales, Chris
    Dalarna University, School of Technology and Business Studies, Energy Technology.
    Ochs, Fabian
    Dermentzis, Georgios
    Nouvel, Romain
    Cotrado, Mariela
    D6.3a Performance of the Studied Systemic Renovation Packages - Method2015Report (Other academic)
    Abstract [en]

    One of the primary objectives of the iNSPiRe project was to develop a tool that predicts the energy and cost saving impacts of various systemic retrofit interventions. This tool is now available for all those involved in the renovation of older buildings (from consulting offices, moving through construction companies and to decision makers) to use as a means of selecting which retrofit package will deliver the greatest costs savings and most improved energy efficiencies.To this purpose, we have produced three databases that provide valuable information about the energy performance of a variety of buildings in different climates, based on different energy requirements. These are the results of a three stage process:1. Collection of energy use data (statistics) for the whole of EU 27, the structuring of a building stock database and the definition of reference buildings that represent the most typical buildings of the building stock. Data for six different age categories were derived, including typical construction information and insulation standards for these periods. Seven climatic regions were also defined to cover the EU 27. The structured data are available in the Building Stock Statistics database.2. Derivation of a complete and consistent database of heating and cooling demands in residential and office buildings covering the whole of the EU 27 based on the simulation of the defined reference buildings in seven climatic regions. The simulations were calibrated against the energy use statistics, and are thus consistent with these, but offer the full range of heating and cooling demands for all climates and building types for six different age categories. The results are available in the Reference Building Simulation database.3. Definition of a range of retrofit measures for the reference buildings including climatic shell, HVAC system and heating/cooling distribution. The matrix of these measures was then simulated for all building types for the seven different climatic regions to provide data for the third database, the Systemic Renovation Packages database.

  • 59. Fedrizzi, Roberto
    et al.
    Dipasquale, Chiara
    Bellini, Alessandro
    Gustafsson, Marcus
    Dalarna University, School of Technology and Business Studies, Energy Technology.
    Bales, Chris
    Dalarna University, School of Technology and Business Studies, Energy Technology.
    Ochs, Fabian
    Dermentzis, Georgios
    Nouvel, Romain
    Cotrado, Mariela
    D6.3b Performance of the Studied Systemic Renovation Packages - Single Family Houses2015Report (Other academic)
    Abstract [en]

    One of the primary objectives of the iNSPiRe project was to develop a tool that predicts the energy and cost saving impacts of various systemic retrofit interventions. This tool is now available for all those involved in the renovation of older buildings (from consulting offices, moving through construction companies and to decision makers) to use as a means of selecting which retrofit package will deliver the greatest costs savings and most improved energy performance.The whole set of Renovation Packages in the published database includes results for a range of SFH typologies, from detached to row houses, with different external surface over building volume ratio.In order to compare the same Envelope Renovation when applied to different SFH typologies and climates, we adopted the detached constructions as the basis to define insulation, windows and mechanical ventilation measures that match the heating demand standards sought (15, 25, 40, 70 kWh/m2y). Since the solutions found are the most conservative, lower heating demands are obtained for semi-detached and row houses.The solutions elaborated in terms of window features, and walls/roof cross sections and materials, are reported in Deliverable 6.3a for the whole range of buildings and the 7 climates analysed.In this document we comment the results relative to the reference buildings built 1945-1970, renovated with four generation systems (AWHP, GWHP, gas boiler and biomass boiler) and three distribution systems (radiant ceilings, radiators and fan coils). In order to limit the number of solutions discussed, here we report results only for the detached SFHs. The full range of solutions is published on the iNSPiRe website.The generation plants are hybrid solutions designed to combine heat pumps or boilers with solar thermal and/or PV technologies. These combinations integrate multiple renewable energy sources, thus allowing to reach in the best cases the 50 kWh/m2y primary energy consumption limit that is the objective of the retrofit packages devised.

  • 60. Fedrizzi, Roberto
    et al.
    Dipasquale, Chiara
    Bellini, Alessandro
    Gustafsson, Marcus
    Dalarna University, School of Technology and Business Studies, Energy Technology.
    Bales, Chris
    Dalarna University, School of Technology and Business Studies, Energy Technology.
    Ochs, Fabian
    Dermentzis, Georgios
    Nouvel, Romain
    Cotrado, Mariela
    D6.3c Performance of the Studied Systemic Renovation Packages - Multi-Family Houses2015Report (Other academic)
    Abstract [en]

    In this report, we comment the results relative to the reference buildings built within the first age (1945-1970), and renovated with 4 generation systems (air to water heat pump, ground water heat pump, gas boiler and biomass boiler) and 3 distribution systems (radiant ceilings, radiators and fan coils).According to the buildings classification (see D2.1a and D2.1c), two different Multi Family Houses typologies are identified, small Multi Family House (s-MFH) and large Multi Family House (l-MFH). In the published database, only s-MFHs are included, varying the number of floors (3, 5 and 7 floors) and, consequently, the surface over volume (S/V) ratio.As well as for the SFHs, we adopted a reference S/V ratio as the basis to define insulation, windows and mechanical ventilation measures to match the sought heating demand targets (15, 25, 45, 70 kWh/m²y), that is 5 floors and 10 apartments.

  • 61.
    Fiedler, Frank
    et al.
    Dalarna University, School of Technology and Business Studies, Energy Technology.
    Bales, Chris
    Dalarna University, School of Technology and Business Studies, Energy Technology.
    Persson, Jannika
    Dalarna University, School of Technology and Business Studies, Construction.
    Gustavsson, Marcus
    Dalarna University, School of Technology and Business Studies, Energy Technology.
    Kovacs, Peter
    RISE.
    Hemlin, Olleper
    RISE.
    Ollas, Patrik
    RISE.
    Thuvander, Liane
    Chalmers Tekniska Högskolan.
    Femenías, Paula
    Chalmers Tekniska Högskolan.
    Lundin, Michelle
    Chalmers Tekniska Högskolan.
    Larsson, David
    Solkompaniet.
    Miljontak Delprojekt 2: Sammanfattning av litteratursammanställning2018Report (Other academic)
  • 62.
    Filatov, Artem
    Dalarna University, School of Technology and Business Studies, Energy Technology.
    Concentrating Collector for Torsång District Heating System2018Independent thesis Advanced level (degree of Master (Two Years)), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    In this thesis report for Dalarna University in Borlange and Absolicon company the study of a possibility to add an array of concentrating solar collectors to a Torsång district heating system was done. The whole idea of this work was to make a simulation of this kind of system, trying to get 15-20% of solar fraction, and make an economical evaluation.

    At the same time, another goal was to make two comparisons: between concentrating and flat-plate collector in the same system, and between two tools for collector analysis – Polysun and Absolicon tool, based on TRNSYS, which was designed to estimate the output of the collector for a certain temperature, without any load.

    During the study, the analysis of the simulating tools was made and the combination of those two tools was used. Using long iteration cycles, involving changing the field layout, number of collectors and distance between collector rows in flat-plate collector case, both types of collectors were analyzed. The method of the analysis was to get an equal output of the field and see the differences, which appear while using different collector types.

  • 63. Freitas, Iuri
    et al.
    Zhang, Xingxing
    Dalarna University, School of Technology and Business Studies, Energy Technology.
    Green building rating systems in Swedish market: A comparative analysis between LEED, BREEAM SE, GreenBuilding and Miljöbyggnad2018In: Energy Procedia, ISSN 1876-6102, E-ISSN 1876-6102, Vol. 153, p. 402-407Article in journal (Refereed)
    Abstract [en]

    In Sweden, there are four most commonly used green building rating systems, which are LEED, BREEAM SE, GreenBuilding and Miljöbyggnad. In this study, each of them is analyzed under the aspects of certification process, implementation cost, educational needs and the variety of categories. SWOT method is further applied to extract the strengths, weaknesses, opportunities and threats of each of the rating system in a direct and indirect manner, making it clearer to choose among various options when considering the individual needs of each project in practice. 

  • 64.
    Frota de Albuquerque Landi, Fabiana
    Dalarna University, School of Technology and Business Studies, Energy Technology.
    Energy Performance Contracting in Swedish scenario: a case study with Morastrand AB2018Independent thesis Advanced level (degree of Master (Two Years)), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Renovation of the existing buildings in Sweden represents a great potential to achieve the

    energy efficiency and carbon emission targets set by the European Union and the Swedish

    government. The Energy Performance Contracting (EPC) is regarded as an efficient way

    to manage and to outsource the risks of energy efficiency (EE) measures.

    The thesis aims to identify the theoretical framework of EPC in the Swedish scenario and,

    through a real case, develop a model that relates EE measures and its results considering

    the capital investment versus running costs of renovation projects.

    The work is based on the incorporation with the Morastrand AB. The research expects to

    assess EPC processes and measures as in Energy Service Companies (ESCO) and

    consequently help in the decision making and the management of the projects.

    The thesis is composed of two parts. The first part identifies the theoretical framework of

    energy contract models focusing on the EPC, while a case study with Morastrand AB is

    subsequently presented. It is suggested one approach for the preliminary comparison of

    different renovation measures in EE projects, corresponding to the first step of the

    planning phase of an EPC.

    General recommendations and sensitive factors were identified and can assist Morastrand

    AB to effectively implement EE projects in the future. For orienting investments, the

    Lifecycle Cost Analysis (LCCA) is a method to study solutions under economic aspects

    and further it can be extended to the complete Lifecycle Assessment of the upcoming

    projects.

    The theoretical framework of the EPC is composed by identifying the projects, performing

    the technical analysis, determinizing the potential in energy savings, deepening the

    analysis with auditions, tendering the project, designing and executing the project,

    commissioning, operating and supporting the systems with constant monitoring and

    maintenance.

    The biggest challenge for the EPC in Sweden is the relation between the ESCOs and their

    clients. The figure of the facilitator could improve the results and balance the knowledge

    gap between the parts.

    The actors of these projects are the ESCO, the client, the facilitator and the financing part.

    In Sweden, very frequently the client finances the operation. There are a few models of

    contracting, and the most popular are guaranteed savings and shared savings.

    The thesis performed the LCCA of three options for window replacement in a building at

    the end of its lifespan. The results show that the trends in prices and interest rates are

    sensitive factors. In this case, the projects with higher initial investments were more

    profitable. Those solutions can shield the company against energy prices escalates and

    contribute to the green policies.

  • 65.
    Gerardi, Marcelin
    et al.
    Dalarna University, School of Technology and Business Studies, Energy Technology.
    Namsrai, Miki
    Dalarna University, School of Technology and Business Studies, Energy Technology.
    A software system for variables comparison of a paper machine for improved performance2018Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Today paper is to find everywhere, and the production factories always need to increase the

    productivity if they want to stay competitive. Stora Enso Kvarnsveden has one of the biggest

    magazine paper machines in the world, which produces around 1900 meters of paper per

    minute. The production process is highly automatized, which reduces the number of operators

    that work on the machine. Still, process variations can cause brakes in the paper web and lead

    to loss of income, energy and paper production. It may also have a direct impact on the paper

    quality. This report is focusing the following question:

    How to keep the Paper Machine production process under controlled conditions?

    To make a data analysis fully relevant, we need to use the most important variables of the

    machine. By analyzing these data some unexpected behavior and variation of process values

    can be pointed out. The analyzing tool needs to be fast and portable, and therefore a software

    system has been developed. By comparing process data with reference data this software can

    make a powerful analysis.

    The created software is intended to be used either by operators or engineers. The most

    important results are collected in a file. In this text file, the comparison function gives the

    results which are stored in a CSV-format. Furthermore, an auto-update function allows the

    users to run it automatically. Graphical presentations are supporting the interpretation of the

    results.

  • 66.
    Ghaghazanian, Arash
    Dalarna University, School of Technology and Business Studies, Energy Technology.
    System Integration of PV/T Collectors in Solar Cooling Systems2015Independent thesis Advanced level (degree of Master (Two Years)), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    The demand for cooling and air-conditioning of building is increasingly ever growing. This increase is mostly due to population and economic growth in developing countries, and also desire for a higher quality of thermal comfort. Increase in the use of conventional cooling systems results in larger carbon footprint and more greenhouse gases considering their higher electricity consumption, and it occasionally creates peaks in electricity demand from power supply grid. Solar energy as a renewable energy source is an alternative to drive the cooling machines since the cooling load is generally high when solar radiation is high.

    This thesis examines the performance of PV/T solar collector manufactured by Solarus company in a solar cooling system for an office building in Dubai, New Delhi, Los Angeles and Cape Town. The study is carried out by analyzing climate data and the requirements for thermal comfort in office buildings. Cooling systems strongly depend on weather conditions and local climate. Cooling load of buildings depend on many parameters such as ambient temperature, indoor comfort temperature, solar gain to the building and internal gains including; number of occupant and electrical devices.

    The simulations were carried out by selecting a suitable thermally driven chiller and modeling it with PV/T solar collector in Polysun software. Fractional primary energy saving and solar fraction were introduced as key figures of the project to evaluate the performance of cooling system. Several parametric studies and simulations were determined according to PV/T aperture area and hot water storage tank volume.

    The fractional primary energy saving analysis revealed that thermally driven chillers, particularly adsorption chillers are not suitable to be utilizing in small size of solar cooling systems in hot and tropic climates such as Dubai and New Delhi. Adsorption chillers require more thermal energy to meet the cooling load in hot and dry climates. The adsorption chillers operate in their full capacity and in higher coefficient of performance when they run in a moderate climate since they can properly reject the exhaust heat. The simulation results also indicated that PV/T solar collector have higher efficiency in warmer climates, however it requires a larger size of PV/T collectors to supply the thermally driven chillers for providing cooling in hot climates. Therefore using an electrical chiller as backup gives much better results in terms of primary energy savings, since PV/T electrical production also can be used for backup electrical chiller in a net metering mechanism.

  • 67.
    Gilén, Karolina
    et al.
    Dalarna University, School of Technology and Business Studies, Energy Technology.
    Haglund, Arvid
    Dalarna University, School of Technology and Business Studies, Energy Technology.
    Sammankoppling av fjärrvärmenät: Transiteringsledning mellan Borlänge, Ornäs och Torsång2019Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Borlänge Energi, BE, owns small district heating, DH, networks in Ornäs and Torsång outside Borlänge, these have high operating costs that are not weighed up by the revenue they make, due to this BE makes a yearly loss on them. Because of this BE wants to connect the small DH networks with the main DH network in Borlänge where the production costs are lower. The technical and economical prerequisites for a connection have therefore been studied.

    Previous literature has been studied regarding economic parameters for connection of DH networks. Unfortunately, the type of connection that is studied in this report has not been found. The studied literature covers expansion of DH network and connection of larger DH networks, and in most cases, the connecting networks have different owners.

    Three possible routes were chosen for the connection with Borlänges DH. The current load for Ornäs and Torsång as well as possible new customers was calculated and used to dimension the pipes and calculate the costs for three different scenarios with different loads. Thereafter the costs and incomes from a connection has been calculated, and then used in BEs capital budget where the pay-off time was calculated based on the discounting method. The capital budgets showed that all the routes except one in the base case were profitable within the time frame of 30 years that was set by BE for investments in DH. Sensitivity analyses were made for pay-off time, construction costs and pipe dimension, which showed that the pay-off time is affected by several factors. But was mostly affected if production costs increase or if pipes are dimensioned for a much larger load than what actually is connected in the end. The number of new customers is therefor important to ensure before building the interconnecting pipe. Pipe dimension was affected most by the load as the transition losses are relatively small, and the building costs were affected most by the cost of the DH pipes since they constitute a large part of those costs.

    Besides from the technical and economical results it has been shown that each and all of the routes have its own prerequisites, where each route has its own pros and cons. All-in-all one route has been chosen as more suitable than the other two, as it besides one of the shortest pay off times also include possibilities to connect new customers along the route.

    As district heating is dependent on local conditions, in regard to both the technical aspects and the soil composition, the report includes several simplifications and assumptions, which have been made based on local conditions and experience. It is necessary to take this into consideration before attempting to apply the findings of this report in other places than Borlänge.

  • 68.
    Gradén, Mattias
    Dalarna University, School of Technology and Business Studies, Energy Technology. Uppsala universitet, Kulturgeografiska institutionen.
    Storskalig vindkraft i skogen: Om rationell planering och lokalt motstånd2016Doctoral thesis, monograph (Other academic)
    Abstract [en]

    The global climate threat has intensified Sweden’s ambitions to build wind power stations. This thesis explores the planning of, and opposition to, wind power in the inland rural and forest regions of Sweden. It is in these autonomous communities that the plans are implemented and the aim of the thesis was to, from a local perspective, understand and analyse the planning and acceptance challenges that large-scale wind power development faces in places that are both sparsely populated and have good wind conditions.

    This thesis is based on qualitative methods and was conducted as two studies. The case study area comprises four municipalities in Dalarna County. The first study analyses the planning and establishment process in three municipalities using interviews and an analysis method called process tracing. The second study analyses one wind power establishment, in which the interviews form the basis for a discourse analytical approach.

    One striking finding highlights the relationship between the global and the local. Global environment and energy aspects are absent in the local process, and wind power becomes a technical land issue that clashes with other local land interests. Another finding of the study reveals that planning for wind power establishment follows a rational planning tradition. The feelings and memories of the individual – different views regarding the landscape – play a background role in the formal permit process, while measurable observable conditions have a more prominent role. Wind power developers thereby acquire a more significant position than what they probably would have had if the planning had included local residents’ views on wind power in the landscape at an early stage.

  • 69.
    Graefenhain, Marcus
    Dalarna University, School of Technology and Business Studies, Energy Technology.
    Energy Yield Simulation Analysis of Bifacial PV Installations in the Nordic Climate2017Independent thesis Advanced level (degree of Master (Two Years)), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Recently, commercial softwares for PV system simulation released bifacial extensions. While research laboratories have developed their own simulation tools, in both cases it is imperative to display their applicability, as well as continuously assess their accuracy and/or limitations in practice, i.e. for different bifacial PV systems and field conditions. This paper presents a design and energy yield simulation study of two bifacial PV systems installed and operating in Nordic climate conditions, i.e. in Vestby, Norway (

    System 1) and in Halmstad, Sweden (System 2). The aim of this study is:

    • • To validate and compare the accuracy of two bifacial PV simulation tools newly featured in the software platforms of PVsyst and Polysun respectively, against real-field energy yield data.

    Each investigated system is modeled and analyzed with both simulation tools, resulting in four individual case stu

    dies. Further details on the systems’ monitoring set-up, the data input, modeling steps, and the involved uncertainties are presented in this paper.

    The results of the four case studies show higher percent deviations (both monthly and hourly data) between simulated energy results and real energy results during winter periods compared to summer periods. System 1 had a lower bifacial gain (around 2%) than System 2 which ranges from 2% in summer periods to 25% during winter.

    The collected field data had too high of an uncertainty to determine whether the bifacial PV simulation extensions are accurate within a certain tolerance. The reason for higher simulation inaccuracy in the winter is due to: lower production, higher uncertainty in albedo, and more diffuse irradiation.

    It is recommended for the bifacial PV simulation extensions include options for considering a variable albedo. The bifacial gain in System 2 was higher in the winter because of the higher albedo value given whereas in System 1, the albedo value was kept constant. Further parametric studies should be conducted on the bifacial gain using vertical mounted bifacial PV modules oriented east and west for Nordic climate conditions.

  • 70.
    Grälls, Gustav
    et al.
    Dalarna University, School of Technology and Business Studies, Energy Technology.
    Kemell, Tim
    Dalarna University, School of Technology and Business Studies, Energy Technology.
    Energieffektivisering av glödskalsspolning: Utredning av högtryckssystem för glödskalsspolning, med avseende på energieffektiviserande förbättringar och förslag till åtgärder.2016Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    The hot rolling mill at SSAB in Borlänge uses large amounts of electricity every year. The work of systematically reducing energy usage is an ongoing process, both for the sake of the environment but also for increasing profit in the production. The high pressure system for descaling uses 20 GWh of electricity every year. This is about 10 % of the hot rolling mills total electricity usage. The steel slabs are heated before being rolled. This causes iron and oxygen to react with each other and form a scale. This scale is not desired in steel production which is why several methods to remove it have been developed. The method being used at SSAB is high pressure water descaling.

    Large volumes of water are being pressurized and sprayed through nozzles in thin triangle-like jets against the steel. To remove the scale a certain amount of energy is required. It can be calculated by using impingement pressure as a function of specific water rate (amount of water per square meter). This thesis is based on the assumption that the energy usage in the total system can be reduced without reducing the amount of energy that strikes the steel surface. The total efficiency of the system is today 39 %.

    A big contribution to the low efficiency is that all pumps are running on constant rotational speed. They need a minimal flow of water through them for cooling. This minimal flow is according to the manufacturer supposed to be 12 m3/h, but in reality they run at 30 m3/h. This is because of wear in the relief valves that are supposed to reduce the drainage flow. The relief valves are also designed to close the minimal flow to drain during descaling. This is not working as it should and water is flowing to drain during descaling. This result in the yearly energy usage increasing with 3 GWh. Additionally, because of the increased flow to the drain, energy usage is increased by around 6 %. The accumulators being used, four in total at 7 m3 each, are not used in an optimal way. Some observations have been done and at those times the tanks have been filled with about 50 % water. An accumulator should, according to theory, be empty when reaching lowest allowed system pressure. As being used today only a few percent of the tanks water volume can be used.

    A suggestion of bigger change that has been developed is to change pumps and to install bigger accumulators at the furnace and roughing descaler. This would then be made into a separate system, separated from the finishing descaler. An advantage with separate systems is that the parts can be dimensioned for different pressures. This could be especially interesting if piston pumps are installed in the accumulator system.

  • 71. Gu, Yaxiu
    et al.
    Zhang, Xingxing
    Dalarna University, School of Technology and Business Studies, Energy Technology.
    Myhren, Jonn Are
    Dalarna University, School of Technology and Business Studies, Construction.
    Han, Mengjie
    Dalarna University, School of Technology and Business Studies, Microdata Analysis.
    Chen, Xiangjie
    Yuan, Yanping
    Techno-economic analysis of a solar photovoltaic/thermal (PV/T) concentrator for building application in Sweden using Monte Carlo method2018In: Energy Conversion and Management, ISSN 0196-8904, E-ISSN 1879-2227, Vol. 165, p. 8-24Article in journal (Refereed)
    Abstract [en]

    The solar energy share in Sweden will grow up significantly in next a few decades. Such transition offers not only great opportunity but also uncertainties for the emerging solar photovoltaic/thermal (PV/T) technologies. This paper therefore aims to conduct a techno-economic evaluation of a reference solar PV/T concentrator in Sweden for building application. An analytical model is developed based on the combinations of Monte Carlo simulation techniques and multi energy-balance/financial equations, which takes into account of the integrated uncertainties and risks of various variables. In the model, 11 essential input variables, i.e. average daily solar irradiance, electrical/thermal efficiency, prices of electricity/heating, operation & management (OM) cost, PV/T capital cost, debt to equity ratio, interest rate, discount rate, and inflation rate, are considered, while the economic evaluation metrics, such as levelized cost of energy (LCOE), net present value (NPV), and payback period (PP), are primarily assessed. According to the analytical results, the mean values of LCOE, NPV and PP of the reference PV/T connector are observed at 1.27 SEK/kW h (0.127 €/kW h), 18,812.55 SEK (1881.255 €) and 10 years during its 25 years lifespan, given the project size at 10.37 m2 and capital cost at 4482–5378 SEK/m2 (448.2–537.8 €/m2). The positive NPV indicates that the investment on the selected PV/T concentrator will be profitable as the projected earnings exceeds the anticipated costs, depending on the NPV decision rule. The sensitivity analysis and the parametric study illustrate that the economic performance of the reference PV/T concentrator in Sweden is mostly proportional to solar irradiance, debt to equity ratio and heating price, but disproportionate to capital cost and discount rate. Together with additional market analysis of PV/T technologies in Sweden, it is expected that this paper could clarify the economic situation of PV/T technologies in Sweden and provide a useful model for their further investment decisions, in order to achieve sustainable and low-carbon economics, with an expanded quantitative discussion of the real economic or policy scenarios that may lead to those outcomes.

  • 72. Gustafsson, M.
    et al.
    Rönnelid, Mats
    Dalarna University, School of Technology and Business Studies, Energy Technology.
    Trygg, L.
    Karlsson, B.
    CO2 emission evaluation of energy conserving measures in buildings connected to a district heating system: Case study of a multi-dwelling building in Sweden2016In: Energy, ISSN 0360-5442, E-ISSN 1873-6785, Vol. 111, p. 341-350Article in journal (Refereed)
    Abstract [en]

    When taking action to fulfill the directives from the European Union, energy conserving measures will be implemented in the building sector. If buildings are connected to district heating systems, a reduced heat demand will influence the electricity production if the reduced heat demand is covered by combined heat and power plants.This study analyze five different energy conserving measures in a multi-dwelling building regarding how they affect the marginal production units in the district heating system in Gävle, Sweden. For CO2 emission evaluations, two different combinations of heat and electricity conserving measures are compared to an installation of an exhaust air heat pump.The different energy conserving measures affect the district heating system in different ways. The results show that installing an exhaust air heat pump affects the use/production of electricity in the district heating system most and electricity conserving measures result in reduced use of electricity in the building, reduced use of electricity for production of heat in the district heating system and an increase of electricity production.The conclusion is that electricity use in the building is the most important factor to consider when energy conserving measures are introduced in buildings within the district heating system in Gävle.

  • 73.
    Gustafsson, Marcus
    Dalarna University, School of Technology and Business Studies, Energy Technology. KTH, Strömnings- och klimatteknik.
    Energy Efficient Renovation Strategies for Swedish and Other European Residential and Office Buildings2017Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    The high energy use in the European building stock is attributable to the large share of old buildings with poor energy performance. Energy renovation of buildings is therefore vital in the work towards energy efficiency and reduced environmental impact in the EU. Yet, the strategies and energy system implications of this work have not been made clear, and the rate of building renovation is currently very low.

    The aim of this thesis is to investigate the economic and environmental aspects of energy renovation strategies, with two main objectives:

    • Renovation of Swedish district heated multi-family houses, including life-cycle cost and environmental analysis and impact on the local energy system;

    • Renovation of European residential and office buildings, including life-cycle cost and environmental analysis and influence of climatic conditions.

    Buildings typical for the respective regions and the period of construction 1945-1970 were simulated, in order to determine the feasibility and energy saving potential of energy renovation measures in European climates. A variety of systems for heating, cooling and ventilation were studied, as well as solar energy systems, with focus on heat pumps, district heating, low-temperature heating systems and air heat recovery.

    Compared to normal building renovation, energy renovation can often reduce the life-cycle costs and environmental impact. In renovation of typical European office buildings, as well as Southern European multi-family houses, more ambitious renovation levels can also be more profitable.

    Exhaust air heat pumps can be cost-effective complements in district heated multi-family houses, while ventilation with heat recovery is more expensive but also more likely to reduce the primary energy use. From a system perspective, simple exhaust ventilation can reduce the primary energy use in the district-heating plant as much as an exhaust air heat pump, due to the lower electricity use.

  • 74.
    Gustafsson, Marcus
    et al.
    Dalarna University, School of Technology and Business Studies, Energy Technology.
    Dipasquale, C.
    Poppi, Stefano
    Dalarna University, School of Technology and Business Studies, Energy Technology.
    Bellini, A.
    Fedrizzi, R.
    Bales, Chris
    Dalarna University, School of Technology and Business Studies, Energy Technology.
    Ochs, F.
    Sié, M.
    Holmberg, S.
    Economic and environmental analysis of energy renovation packages for European office buildings2017In: Energy and Buildings, ISSN 0378-7788, E-ISSN 1872-6178, Vol. 148, p. 155-165Article in journal (Refereed)
    Abstract [en]

    A large share of the buildings in Europe are old and in need of renovation, both in terms of functional repairs and energy efficiency. While many studies have addressed energy renovation of buildings, they rarely combine economic and environmental life cycle analyses, particularly for office buildings. The present paper investigates the economic feasibility and environmental impact of energy renovation packages for European office buildings. The renovation packages, including windows, envelope insulation, heating, cooling and ventilation systems and solar photovoltaics (PV), were evaluated in terms of life cycle cost (LCC) and life cycle assessment (LCA) through dynamic simulation for different European climates. Compared to a purely functional renovation, the studied renovation packages resulted in up to 77% lower energy costs, 19% lower total annualized costs, 79% lower climate change impact, 89% lower non-renewable energy use, 66% lower particulate matter formation and 76% lower freshwater eutrophication impact over a period of 30 years. The lowest total costs and environmental impact, in all of the studied climates, were seen for the buildings with the lowest heating demand. Solar PV panels covering part of the electricity demand could further reduce the environmental impact and, at least in southern Europe, even reduce the total costs. © 2017 Elsevier B.V.

  • 75.
    Gustafsson, Marcus
    et al.
    Dalarna University, School of Technology and Business Studies, Energy Technology. KTH.
    Ochs, Fabian
    Univeristy of Innsbruck.
    Birchall, Sarah
    Dermentzis, Georgios
    Univeristy of Innsbruck.
    Bales, Chris
    Dalarna University, School of Technology and Business Studies, Energy Technology.
    Calabrese, Toni (Contributor)
    University of Innsbruck.
    Report on auditing tool for assessment of building needs2015Report (Other academic)
  • 76.
    Gustafsson, Marcus
    et al.
    Dalarna University, School of Technology and Business Studies, Energy Technology. KTH.
    Poppi, Stefano
    Dalarna University, School of Technology and Business Studies, Energy Technology. KTH.
    Bales, Chris
    Dalarna University, School of Technology and Business Studies, Energy Technology.
    Fedrizzi, Roberto
    Dipasquale, Chiara
    Bellini, Alessandro
    Ochs, Fabian
    Univeristy of Innsbruck.
    Dermentzis, Georgios
    Univeristy of Innsbruck.
    Performance of Studied Systemic Renovation Packages – Office Buildings2016Report (Other academic)
  • 77.
    Gustafsson, Marcus
    et al.
    Dalarna University, School of Technology and Business Studies, Energy Technology.
    Swing Gustafsson, Moa
    Dalarna University, School of Technology and Business Studies, Energy Technology.
    Myhren, Jonn Are
    Dalarna University, School of Technology and Business Studies, Construction.
    Bales, Chris
    Dalarna University, School of Technology and Business Studies, Energy Technology.
    Holmberg, Sture
    Techno-economic analysis of energy renovation measures for a district heated multi-family house2016In: Applied Energy, ISSN 0306-2619, E-ISSN 1872-9118, Vol. 177, p. 108-116Article in journal (Refereed)
    Abstract [en]

    Renovation of existing buildings is important in the work toward increased energy efficiency and reduced environmental impact. The present paper treats energy renovation measures for a Swedish district heated multi-family house, evaluated through dynamic simulation. Insulation of roof and façade, better insulating windows and flow-reducing water taps, in combination with different HVAC systems for recovery of heat from exhaust air, were assessed in terms of life cycle cost, discounted payback period, primary energy consumption, CO2 emissions and non-renewable energy consumption. The HVAC systems were based on the existing district heating substation and included mechanical ventilation with heat recovery and different configurations of exhaust air heat pump.Compared to a renovation without energy saving measures, the combination of new windows, insulation, flow-reducing taps and an exhaust air a heat pump gave up to 24% lower life cycle cost. Adding insulation on roof and façade, the primary energy consumption was reduced by up to 58%, CO2 emissions up to 65% and non-renewable energy consumption up to 56%. Ventilation with heat recovery also reduced the environmental impact but was not economically profitable in the studied cases. With a margin perspective on electricity consumption, the environmental impact of installing heat pumps or air heat recovery in district heated houses is increased. Low-temperature heating improved the seasonal performance factor of the heat pump by up to 11% and reduced the environmental impact.

  • 78.
    Gustafsson, Mattias
    et al.
    Högskolan i Gävle.
    Karlsson, Björn
    Högskolan i Gävle.
    Rönnelid, Mats
    Dalarna University, School of Technology and Business Studies, Energy Technology.
    How the electric meter configuration affect the monitored amount of self-consumed and produced excess electricity from PV systems: case study in Sweden2017In: Energy and Buildings, ISSN 0378-7788, E-ISSN 1872-6178, Vol. 138, p. 60-68Article in journal (Refereed)
    Abstract [en]

    This study evaluates how the principal function of bi-directional electric meters affects the monitored amount of self-consumed and produced excess electricity for dwelling buildings connected to the grid by three phases. The electric meters momentarily record the sum of the phases or the phases individually and then summarize the recorded values to a suitable time period and is then collected by the grid owner. In Sweden, both electric meter configurations fulfill laws and regulations.

    The meter configuration affects the monitored distribution of self-consumed and produced excess electricity significantly for the investigated single-family house but is negligible for the investigated multi-dwelling buildings. The monitored self-consumed electricity produced by the PV installation for the single-family house varies between 24% and 55% depending on the configuration and how the inverter is installed for the investigated year. The difference in economic value for the produced electricity varies between 79.3 to 142 Euros.

    Due to the electric meter configuration, the profitability of PV systems will be different for identical single-family houses with identical conditions. This should be corrected for a well-functioning market. It is also important to decide how the configuration should be designed to ensure that different incentives and enablers results in desired effects.

  • 79.
    Gál, Csilla V
    Dalarna University, School of Technology and Business Studies, Energy Technology.
    A városi tér szerkezete és hatása a mikroklímára [Urban space and structure and its effect on the urban microclimate]2017In: 43. Meteorológiai Tudományos Napok. 2017. November 23-24. Mikro- és mezoskálájú légköri folyamatok modellezése. Az előadások összefoglalói. / [ed] István Geresdi, Ferenc Ács, Balázs Szintai, and Tamás Weidinger, Budapest, Hungary, 2017Conference paper (Refereed)
    Abstract [hu]

    A városok sajátos éghajlata, a városklíma, a természetes környezethez képest módosult éghajlattal jellemezhető. A klímaparaméterek városi módosulásának hátterében a beépített felszínek megváltozott energiaháztartása áll. Míg a városok éghajlata markánsan elkülönül a környező természetes területek éghajlatától, a városokon belül is jelentős klimatikus különbségek alakulnak ki. Ezen különbségek kialakulására alapvető hatással van a beépítettség foka, valamint a zöld területek részaránya. A városokon belüli éghajlati különbségek tanulmányozása mérések és numerikus szimulációk révén lehetséges. Utóbbiak segítségével széleskörűen tanulmányozható a beépítettség, a városokra jellemző mesterséges anyagok, valamint a városon belül alkalmazott zöld- és kék infrastruktúra elemeinek hatása a kialakuló mikro- és lokális éghajlatra, illetve mindezek hatása a lakosok komfortérzetére. Eme ismeretanyagra alapozva megfogalmazhatók olyan várostervezési irányelvek, melyekkel az éghajlatváltozással kombinálódó városklíma negatív hatásai mérsékelhetőek, s a városlakók számára klimatikus szempontból élhetőbb környezet teremthető.Tanulmányomban Budapest jellemző városi beépítési formáit, s a köztük lévő mikroklimatikus különbségeket vizsgálom numerikus szimulációk útján, különös tekintettel a nyári hőterhelés mérséklésére irányuló várostervezési beavatkozások eredményességére az egyes beépítési formák esetén. Az egyik ilyen beavatkozás az épülethomlokzatok albedójának növelése nagyobb sugárzás-visszaverő képességű anyagok, illetve festékek alkalmazása révén. Egy másik jellemző beavatkozás a zöldterületek részarányának növelése, melyet tanulmányomban a lombkorona borítás értékének változtatásával vizsgálok. A különféle beépítési formák, homlokzat albedók és korona borítottság értékek komplex hatásának feltárására az ENVI-met szimulációs software-t alkalmaztam. Az eredmények alapján elmondható, hogy a megnövekedett albedó következtében a napsugárzásnak kitett homlokzatok hőmérséklete – s ez által az épületek hőterhelése is – csökken. A visszavert sugárzási hányad megnövekedése azonban az épületek között sugárzás többletként jelenik meg, mely többlet a nem módosított albedójú felületek (utak, terek) nagyobb sugárzási terheléséhez és ezáltal a városi határréteg felmelegedéséhez vezet. Ezzel ellentétben, a korona borítottság növelése a városi határrétegben a rövidhullámú sugárzás és a léghőmérséklet csökkenését eredményezi. Mivel ezen tényezők hatása a lakosok komfortérzetét és az épületeket érő hőterhelést is előnyösen befolyásolja, a közterületek fásítása a nyári hőterhelés mérséklésére irányuló várostervezési beavatkozás egyik hatásos eszköze lehet.

  • 80.
    Gál, Csilla V
    Dalarna University, School of Technology and Business Studies, Energy Technology.
    Mean radiant temperature modeling, A comparative model evaluation2018Conference paper (Refereed)
    Abstract [en]

    As a result of the changing climate with trends of rising temperatures and increasing extreme heat events, urban planners and city officials have recently taken a great interest in improving the climate of cities and maintaining comfortable outdoor conditions in spite of these trends.In order to meet the demand for this special knowledge and to deliver scientific assistance, several numerical models have emerged with an aim to assess the microclimate of cities and their influence on human thermal comfort over the course of the past decade. While these tools differ both in the human thermal comfort indices they deliver and in their numerical modeling approach, they all rely on the calculation of mean radiant temperature—the driving parameter of outdoor human thermal comfort. While the assessment of models lags behind the perpetual software updates and releases, the documentation of many such models is also lacking or insufficient. In addition, a great deal of existing validation studies assess clear cut situations where the site is either sunlit or in shade, whereas conditions in the urban environment are generally more complex. Given both the growing importance the outdoor thermal environment of cities and the role played by these tools, reporting on their performance is of high importance.The aim of this study is to assess the ability of several recently emerged or updated microclimate models to reproduce mean radiant temperature (Tmrt) in a complex urban setting. The evaluation is made against field data obtained by integral radiation measurements. Results indicate that most microclimate models underestimate Tmrt both at sunlit locations and at night, whereas in shade Tmrt is generally overestimated. These errors are related to the surface temperature parametrization, the isotropic sky assumption, simplifications in the reflected shortwave radiation calculation and the incorrect representation of a standing person.

  • 81.
    Gál, Csilla V
    Dalarna University, School of Technology and Business Studies, Energy Technology.
    Modeling mean radiant temperature in outdoor spaces: A comparative numerical simulation and validation study2018Conference paper (Refereed)
    Abstract [en]

    Cities are increasingly under pressure to address the challenges of climate change. One of the most pressing and unifying issue in this respect is the maintenance of comfortable outdoor conditions despite rising air temperatures and increasing extreme heat events. As a means to inform urban planner and city officials, the assessment of outdoor thermal comfort conditions—either via numerical modeling or field measurements—have gained popularity over the past decade. While measurements can deliver highly accurate data, they are expensive and time-consuming endeavors that can only inform us about the conditions in an existing environment on a specific day and time of the year. In contrast, numerical modeling allows us to evaluate alternative urban design scenarios as well as to grasp the spatial and temporal variability of outdoor human thermal comfort conditions.

    Given the advantages of numerical modeling and the increasing computational power of personal computers, several tools have emerged with an aim to assess the microclimate and human thermal comfort impacts of urban planning and design decisions. While these tools differ both in the human thermal comfort indices they deliver and in their numerical modeling approach, they all rely on the calculation of mean radiant temperature, in one way or another. Mean radiant temperature (Tmrt), the driving parameter of human thermal comfort in outdoor spaces, requires the modeling of both short- and long waver radiation fluxes. While different calculation methods exist to deriving this parameter, most models also introduce some kind of numerical simplification to increase computational speed. The multitude of numerical approaches in deriving Tmrt, coupled with the high spatial and temporal variability of this parameter, can result in a range of values delivered by these tools. Given both the growing importance of improving the outdoor thermal environment of cities and the role these tools play in it, reporting on their performance is of high importance.

    The aim of this study is to assess popular microclimate models in their ability to reproduce the complex radiative environment of cities, as indicated by Tmrt, and to inform to the research and design community about their performance, compared to integral radiation measurement derived filed data. While the documentation of some numerical simulation tools is lacking or incomplete, this paper will nevertheless attempt to shed lights on the reasons behind the disparities in the derived Tmrt values. Initial results indicate that most microclimate models have a tendency to underestimate nighttime Tmrt together with daytime values when the location is exposed to the sun. In contrast, when the locations become shaded, Tmrt values are generally overestimated. In general, these errors indicate issues with surface temperature parametrization and point to the greatest challenge of the numerical simulation community.

  • 82.
    Gál, Csilla V
    Dalarna University, School of Technology and Business Studies, Energy Technology.
    The effectiveness of shade trees for urban heat mitigation, a comparative numerical simulation study2016Conference paper (Other academic)
    Abstract [en]

    As a result of climate change, many regions are projected to see increases in air temperatures and extreme heat events over the coming decades. Since these trends are expected to exacerbate existing conditions in cites, urban heat mitigation will be one of the key challenges of the twenty-first century. A frequently advocated means of mitigating urban heat is through shade trees. Through the reduction of air and radiative temperatures trees not only improve outdoor human thermal comfort, but also reduce the cooling loads of buildings. This paper investigates the impact of different canopy cover ratios and tree layouts on the urban microclimate. The numerical simulation study utilizes four characteristic dense urban configurations from Budapest (Hungary) to assess the influences of these factors on the effectiveness of shade trees in mitigating urban heat. The study applies ENVI-met for microclimate simulation and MATLAB for the analysis and visualization of the results. Microclimate conditions within the urban canopy layer are examined on the basis of diurnal air and mean radiant temperatures. Preliminary results indicate that the effectiveness of shade trees is the function of the urban configurations' initial thermal performance. Since microclimate improvements by way of trees are primarily achieved through shading, greatest reduction in radiative temperatures is achieved in configurations with large open spaces. In the case of air temperature, increasing the canopy cover increases the added benefit of temperature reduction—indicating that reduced turbulence can in certain cases be beneficial.

  • 83.
    Gál, Csilla V
    et al.
    Dalarna University, School of Technology and Business Studies, Energy Technology.
    Gulyás, Ágnes
    Kántor, Noémi
    Heat mitigation with shade trees: the role of landscape design and tree parameters in ameliorating summertime heat stress in a Central-European square2017Conference paper (Refereed)
    Abstract [en]

    Climate change projections for Central Europe indicate a significant rise in summertime temperatures and an increase in the frequency and severity of extreme heat events. Combined with the peculiar climate of cities—characterized by the Urban Heat Island effect and reduced ventilation due to high building density—climate change is expected to have more pronounced effects in urban environments. Shade trees are demonstrated to be one of the most effective means to mitigate heat stress in cities. However, very few studies have evaluated systematically the impact of different landscape design and tree parameters (e.g. the species selection or the spatial distribution) on the heat mitigation effectiveness of shade trees. This study aims to assess the role of vegetation transmissivity, canopy size and tree distribution in a medium-sized Central-European square. The rectangular Bartók Square, located in the inner city of Szeged (Hungary), was selected as a study area. The numerical simulations were carried out with the radiation model SOLWEIG (v.2015a). The necessary meteorological data, collected on clear and warm summer day, was obtained from a nearby weather station run by the Hungarian Weather Service. The default model was built on the basis of available GIS data and utilized tree related parameters from detailed field measurements (tree location, canopy size and shape, etc.). Crown transmissivity data originated from a preliminary, long-term radiation measurement survey covering the vegetation period. Alternative scenarios were constructed with the following characteristics:1) keeping the original tree layout of the square, the initial tree crown transmissivity of 0.0678 was changed to small (0.0243) and high (0.1328) values;2) keeping the original canopy volume, two additional scenarios were introduced with evenly distributed trees of different crown sizes: that of several small trees and of fewer large ones;3) keeping the original canopy volume and using the same number and size of trees, we assessed the role of tree distribution by introducing a scenario were the trees were arranged along the bounding facades of the square—this scenario was compared to the evenly distributed configuration. In order to evaluate the impact of vegetation, all scenarios are reported in reference to a theoretical, nonvegetated square. Since several studies revealed that mean radiant temperature (Tmrt) plays a key role in summertime heat stress in the European context, this parameter was selected as performance indicator. Tmrt combines the heat effect of all short-and long-wave radiation fluxes reaching the human body. Our results indicate that when shade is provided for the facades only, the nighttime Tmrt surplus nearly disappears. However, while horizontal long-wave radiation fluxes have a greater impact on human thermal comfort due to the different absorption coefficients of the human body (0.7 vs. 0.95 for short and long-wave radiation, respectively), providing shade for the facades only is not a successful daytime heat mitigation strategy in open urban places. Comparing the influence of vegetation transmissivity revealed that low transmissivity species were able to reduce Tmrt by only 2C on average during the day. According to our case study, when transmissivity and canopy volume is kept constant, considerable mean radiant temperature reduction can be achieved by evenly distributed mature trees.

  • 84.
    Gómez, Camilo Andrés
    Dalarna University, School of Technology and Business Studies, Energy Technology.
    Influence of Vacuum in Heat Losses of Parabolic Trough Solar Receivers2016Independent thesis Advanced level (degree of Master (Two Years)), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    In comparison with conventional power plants and other renewable technologies,

    the current cost of a Concentrating Solar Power plant is still very high. This

    situation has made the industry have the necessity to research in this field to

    improve efficiency and for a near future have lower cost. One of the developed field

    to improve the efficiency is to decrease the heat losses in the system therefore,

    having a better efficiency in the system.

    In this project, in collaboration of the Solar Platform of Almeria (PSA) in Spain, the

    purpose was to analyses the heat losses of a commercial parabolic trough solar

    receiver at different pressures inside the receiver (at the annulus space). The

    objective was finding the behavior of the heat losses as the pressure inside the

    receiver is increasing allowing convection between the absorber and the glass

    envelope. The PSA has developed a test bench in order to test any kind of linear

    solar receptor named HEATREC. The HEATREC allows to measure the heat

    losses of the receiver in a controlled environment at different temperatures. The

    receiver suffered a minor modification so the pressure in the annulus space can be

    control at will.

    The results shown in this experiment are represented mainly in two types of

    graphics. The first type shows the heat losses as a function of the temperature of

    the absorber tube, this one is used as a comparison with previews research to see

    if is having a correct behavior regardless the pressure in the annulus space is

    being change. The second type shows the heat losses as a function of the

    pressure in the annulus space inside the receiver. The experimental data show that

    there is a remarkable increase in the heat losses as the pressure inside the

    annulus space of the receiver increase and that it can be seen that there are two

    major points in the pressure where the heat losses increase drastically (from 10# to

    10$ mbar and from 10%& to 10%# mbar).

  • 85.
    Haller, Michel
    et al.
    Institut für Solartechnik SPF, Hochschule für Technik HSR.
    Carbonell, Dani
    Institut für Solartechnik SPF, Hochschule für Technik HSR.
    Bertram, Erik
    Institut für Solarenergieforschung Hameln ISFH.
    Heinz, Andreas
    Institut für Wärmetechnik, Technische Universität Graz.
    Bales, Chris
    Dalarna University, School of Technology and Business Studies, Energy Technology.
    System simulations2015In: Solar and Heat Pump Systems for Residential Buildings / [ed] Jean-Christophe Hadorn, John Wiley & Sons, 2015, 1, p. 274-Chapter in book (Refereed)
  • 86.
    Han, Mengjie
    et al.
    Dalarna University, School of Technology and Business Studies, Microdata Analysis.
    May, Ross
    Dalarna University, School of Technology and Business Studies, Microdata Analysis.
    Zhang, Xingxing
    Dalarna University, School of Technology and Business Studies, Energy Technology.
    Wang, Xinru
    Pan, Song
    Yan, Da
    Jin, Yuan
    A novel reinforcement learning method for improving occupant comfort via window opening and closingManuscript (preprint) (Other academic)
  • 87.
    Han, Mengjie
    et al.
    Dalarna University, School of Technology and Business Studies, Statistics.
    May, Ross
    Dalarna University, School of Technology and Business Studies, Microdata Analysis.
    Zhang, Xingxing
    Dalarna University, School of Technology and Business Studies, Energy Technology.
    Wang, Xinru
    Pan, Song
    Yan, Da
    Jin, Yuan
    Xu, Liguo
    A review of reinforcement learning methodologies for controlling occupant comfort in buildings2019In: Sustainable cities and society, ISSN 2210-6707, Vol. 51, article id 101748Article in journal (Refereed)
  • 88.
    Han, Mengjie
    et al.
    Dalarna University, School of Technology and Business Studies, Microdata Analysis.
    Zhang, Xingxing
    Dalarna University, School of Technology and Business Studies, Energy Technology.
    Xu, Liguo
    May, Ross
    Pan, Song
    Wu, Jinshun
    A review of reinforcement learning methodologies on control systems for building energy2018Report (Other academic)
    Abstract [en]

    The usage of energy directly leads to a great amount of consumption of the non-renewable fossil resources. Exploiting fossil resources energy can influence both climate and health via ineluctable emissions. Raising awareness, choosing alternative energy and developing energy efficient equipment contributes to reducing the demand for fossil resources energy, but the implementation of them usually takes a long time. Since building energy amounts to around one-third of global energy consumption, and systems in buildings, e.g. HVAC, can be intervened by individual building management, advanced and reliable control techniques for buildings are expected to have a substantial contribution to reducing global energy consumptions. Among those control techniques, the model-free, data-driven reinforcement learning method seems distinctive and applicable. The success of the reinforcement learning method in many artificial intelligence applications has brought us an explicit indication of implementing the method on building energy control. Fruitful algorithms complement each other and guarantee the quality of the optimisation. As a central brain of smart building automation systems, the control technique directly affects the performance of buildings. However, the examination of previous works based on reinforcement learning methodologies are not available and, moreover, how the algorithms can be developed is still vague. Therefore, this paper briefly analyses the empirical applications from the methodology point of view and proposes the future research direction.

  • 89.
    Hathout, Ahmed
    Dalarna University, School of Technology and Business Studies, Energy Technology.
    A Comprehensive PV Systems Installation Guide and Designing a Roof-Based PV System as a Demonstration System for Troubleshooting Errors in PV systems Installations2018Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    The purpose of the thesis was to make a comprehensive guide for PV systems installers and engineers, using the best practices and following the applicable regulations and standards for the mechanical and electrical installations of PV systems. The guide includes all the different aspects of a PV system installation including different types of roofs and mounting structures, fire safety, height safety and fall protection, installation precautions, electrical and mechanical installations, safety gears and finally system commissioning.

    The guide was developed by reviewing the various standards and best practices deployed in various countries that are pioneers in PV installations as Germany, UK and the US in the period from 2006-2018.

     

    A troubleshooting errors scheme was conducted to help installers track down operational faults in a PV system. Installers will be able to identify problems of old or newly installed PV systems according to few procedures to resolve operational problems.

     

    In addition, a PV system was designed on the rooftop of Högskolan Dalarna in Sweden. The system will be used as a learning platform for installers in a course that will be introduced on the University’s campus, aimed at educating installers on PV systems installations. The designed system mainly focuses on flat and pitched roofs installations.

    The system was designed with the main priority to benefit installers working on and installing the system. Performance ratio and energy yield of the system were not emphasized when designing the system. It was specifically designed to match the objectives of the university’s installer’s course to be conducted on the campus. The designed system consists of two sub-arrays with two different mounting structures. The first one was a pitched roof mounting structure installed on a small hut on the university’s rooftop, and the second sub-array was a ballast mounting system directly situated on the roof surface with no penetrations to its surface. The system was designed on Sketchup software as a 3D model, simulated in PVsyst for energy yield forecast and losses evaluations, drawn as a single line electrical diagram on AutoCAD and lastly, a bill of materials was conducted with all the necessary components and parts to install the system on the rooftop.

     

    Results from the simulated system shows a steep drop in energy yield during the winter months, energy losses due to shading effects of approximately 5 % and minimal other system and cables losses were recorded.

     

    A study visit for a pitched roof PV system installation to be carried out by a group of six Swedish students was conducted. A discussion about the installation procedure, major mistakes and lack of practical knowledge by the engineering students were analyzed.

    Possessing knowledge of PV systems installations is of great importance not only to installers, but to solar design engineers. It is a necessity that engineers poses the fundamentals of installing a PV system and follow the applicable standards and best practices during systems design and execution.

  • 90.
    Hathout, Ahmed
    Dalarna University, School of Technology and Business Studies, Energy Technology.
    A Comprehensive PV Systems Installation Guide and Designinga Roof-Based PV System as a Demonstration System for Troubleshooting Errors in PV systems Installations2018Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    The purpose of the thesis was to make a comprehensive guide for PV systems installers and engineers, using the best practices and following the applicable regulations and standards for the mechanical and electrical installations of PV systems. The guide includes all the different aspects of a PV system installation including different types of roofs and mounting structures, fire safety, height safety and fall protection, installation precautions, electrical and mechanical installations, safety gears and finally system commissioning.

    The guide was developed by reviewing the various standards and best practices deployed in various countries that are pioneers in PV installations as Germany, UK and the US in the period from 2006-2018.

    A troubleshooting errors scheme was conducted to help installers track down operational faults in a PV system. Installers will be able to identify problems of old or newly installed PV systems according to few procedures to resolve operational problems.

    In addition, a PV system was designed on the rooftop of Högskolan Dalarna in Sweden. The system will be used as a learning platform for installers in a course that will be introduced on the University’s campus, aimed at educating installers on PV systems installations. The designed system mainly focuses on flat and pitched roofs installations.

    The system was designed with the main priority to benefit installers working on and installing the system. Performance ratio and energy yield of the system were not emphasized when designing the system. It was specifically designed to match the objectives of the university’s installer’s course to be conducted on the campus.

    The designed system consists of two sub-arrays with two different mounting structures. The first one was a pitched roof mounting structure installed on a small hut on the university’s rooftop, and the second sub-array was a ballast mounting system directly situated on the roof surface with no penetrations to its surface. The system was designed on Sketchup software as a 3D model, simulated in PVsyst for energy yield forecast and losses evaluations, drawn as a single line electrical diagram on AutoCAD and lastly, a bill of materials was conducted with all the necessary components and parts to install the system on the rooftop.

    Results from the simulated system shows a steep drop in energy yield during the winter months, energy losses due to shading effects of approximately 5 % and minimal other system and cables losses were recorded.

    A study visit for a pitched roof PV system installation to be carried out by a group of six Swedish students was conducted. A discussion about the installation procedure, major mistakes and lack of practical knowledge by the engineering students were analyzed.

    Possessing knowledge of PV systems installations is of great importance not only to installers, but to solar design engineers. It is a necessity that engineers poses the fundamentals of installing a PV system and follow the applicable standards and best practices during systems design and execution.

  • 91. He, W.
    et al.
    Zhang, Xingxing
    Dalarna University, School of Technology and Business Studies, Energy Technology.
    Solar Heating, Cooling and Power Generation — Current Profiles and Future Potentials2019In: Advanced Energy Efficiency Technologies for Solar Heating, Cooling and Power Generation / [ed] Xudong ZhaoXiaoli Ma, Springer, 2019, p. 31-78Chapter in book (Refereed)
    Abstract [en]

    Due to the large amount of consumption of the fossil fuels, the ecological environment has suffered serious pollution and damage. Solar power technologies provide the best solution to the current energy and environment issues. In past decades, global solar thermal capacity increased rapidly, and now it has been used worldwide to provide heating, cooling and power generation. However, after years of development, solar energy utilization technology still faces problems such as low efficiency, high cost, difficulty in energy storage and unstable energy supply, which have been seriously restricting its applications. This chapter briefly summarizes the concept and classification of solar heating, cooling and power generation. Furthermore, some technology development and potential applications relating to solar heating, cooling and power generation are discussed.

  • 92.
    Heier, Johan
    Dalarna University, School of Technology and Business Studies, Energy Technology.
    Energirenovering av småhus - en förstudie2018Report (Other academic)
    Abstract [en]

    The building stock in Sweden is in great need of renovation, not least our single family houses. The need for renovation does not only consist of maintenance of the buildings, but also increased energy efficiency in order to reach set targets. It is not enough to only make changes to the heating systems, something that is especially common among single family houses in the form of switching to a heat pump, but improvements to the building envelope are also required. Extensive and a broad range of activities have been made for multifamily buildings but for single family houses only smaller, more directed activities have been made. This can partly be due to the difficulty of reaching out to the approximately two million single family house owners in the country who form a much diversified group, with different motivations and wishes (even within the same household), economic conditions and interest for energy renovation.

     Dalarna University has previously performed a number of studies on energy renovation of single family houses from various perspectives, but no holistic study. This study aims to do a review of the knowledge in the field and also engage in a dialogue with chosen actors during seminars and workshops, in order to investigate how the development of energy renovation for single family houses can be moved forward on a national level.

     The study shows that there is a large potential for energy renovation in the single family house stock, but also many barriers that must be overcome. These barriers are to a smaller degree technical, but instead other problem areas dominate such as financing, lack of suitable policy instruments, lack of knowledge among involved actors, regulations etc.. The study has not been able to identify good examples of frameworks covering all the necessary aspects in order to encourage single family house owners to perform energy renovations of sufficient scale. Additionally, the large number of actors required to undertake an extensive energy renovation means that a high level of knowledge, a wide network of contacts and a large commitment are required; something found in few single family house owners. There is also no clear stakeholder willing to engage in this type of turnkey design and building contracting for single family houses.

     The overall assessment of the key actors involved in this pre study is that a broad commitment is required in order for the single family house sector significantly contributing to set targets for improved energy efficiency in buildings. The commitment must be long term as well as including multi- and interdisciplinary research and business development in order to lay the foundations for relevant and effective policy instruments and awareness increasing knowledge interventions.

  • 93.
    Heier, Johan
    Dalarna University, School of Technology and Business Studies, Energy Technology.
    Fjärrkyla från naturgasförångning vid SSAB Borlänge: Förstudie om möjligheter för kyla till bandy- och datalagringshall2014Report (Other academic)
    Abstract [sv]

    Högskolan Dalarna har i samråd med Borlänge Energi utfört en förstudie angående möjligheten att utnyttja kyla från förångningsstationen av naturgas vid SSAB Borlänge för fjärrkyla till närliggande, nyetablerade, kunder i form av en bandyhall samt en datalagringshall. En potentiell plats för placering är Savelgärdet, som ligger i nära anslutning till kylproduktionen på SSAB.

    Överskottet av kyla från SSAB är väldigt beroende av produktionstakten vilket gör att det är många avbrott i varierande längd. En uppskattning baserad på 2013 års driftdata visar att naturgasförångningen skulle kunna generera cirka 8-9 GWh kyla vid 4 °C och en medeleffekt på 1 MW. Till detta tillkommer kyla från förångning av syrgas.

    Förstudien visar att kylbehovet för en bandyhall är begränsat vid de temperaturer på kyla som kommer att kunna produceras vid SSAB. En datalagringshall å andra sidan kan, beroende på storlek, potentiellt utnyttja all kyla som produceras. Här blir även återvinning av värme en relevant fråga. En annan intressant diskussion är hur fjärrkyla från SSAB samt de kylmaskiner som kommer att krävas vid en bandyhall samt en datalagringshall kan kombineras för att få en sådan optimal produktion av kyla som möjligt. Detta blir än mer intressant ifall Borlänge Energi i framtiden väljer att expandera ett fjärrkylsystem till övriga kunder runt Borlänge Centrum, eftersom man kan tänka sig att kylmaskinerna vid en bandyhall och datalagringshall kan användas som en del i hela fjärrkylsystemet och Borlänge Energi inte ensamt behöver investera i reservkapacitet.

  • 94.
    Heier, Johan
    et al.
    Dalarna University, School of Technology and Business Studies, Energy Technology.
    Bergdahl, Martin
    Dalarna University, School of Technology and Business Studies, Construction.
    Börjesson, Petter
    Energiexpertis.
    Paketrenovering i småhus med BELOK Totalmetodik: Resultat som beslutsunderlag vid finansiering med energilån?2014Report (Other academic)
    Abstract [sv]

    Syftet med denna studie är att illustrera en metod för att hjälpa ägare av mindre fastigheter att nå en högre energieffektiviseringsgrad vid renovering genom paketering av åtgärder. Metoden som används, BELOK Totalprojekt, utvecklades ursprungligen för användning ilokaler och kommersiella byggnader, men vår ambition i Dalarna är att visa metodens tillämpning även för mindre fastigheter som småhus. Det som avgör fastighetsägarensbeslut om åtgärdspaket är ofta dels osäkerheten kring vad som är rätt åtgärder men också kring kostnaden och lönsamheten med investerat kapital. Metoden som visas i denna rapport kan avsevärt minska dessa osäkerheter och på så vis även underlätta vid kreditgivares bedömning när eventuella lån ska beviljas.

    I den här studien har fyra typiska småhus av olika ålderskategori genomgått en energianalys för att identifiera tekniskt möjliga åtgärder för att minska energianvändningen. Dessa åtgärder har sedan satts samman till ett antal åtgärdspaket för att slutligen lönsamhetsberäknas med hjälp av BELOK Totalverktyg. Resultaten presenteras i form av internräntediagram, vilket ger ett mått på paketets lönsamhet, årsbehov av köpt energi och primärenergi före och efter åtgärderna samt slutligen årlig energikostnad för varje paket.

    Resultatet visar att det går att göra lönsamma åtgärdspaket som når en halvering av energianvändningen (både köpt energi och primärenergi) i 2 av 4 studerade hus. De två hus som klarar av att lönsamt halvera energianvändningen är båda uppvärmda med el utan värmepump eller energiåtervinning på ventilationen. Det ena huset där en lönsam halvering inte är möjlig är uppvärmt med fjärrvärme och det andra är ett nyare hus som är utrustat med värmeåtervinning på ventilationsluften. Om man har ett relativt billigt uppvärmningssätt (fjärrvärme kontra el) eller om byggnaden redan har en låg energianvändning är det svårt att nå en lönsam halvering. Det går dock att hitta mindre åtgärdspaket som är lönsamma och samtidigt innebär en betydande energieffektivisering.

    En annan slutsats från resultaten är att det är relativt enkelt att göra stora besparingar i både köpt energi och primärenergi i ett eluppvärmt hus genom att installera någon form av värmepump. Att installera en värmepump i ett hus uppvärmt med fjärrvärme kan ge en stor besparing i köpt energi, men ger enbart en måttlig besparing i primärenergi. Att byta från el till förnyelsebar energikälla (pellets i detta fall) ger i ett av exemplen en nästan oförändrad användning av köpt energi medan man når en halvering av primärenergianvändningen. Det är alltså viktigt att poängtera att en kostnadseffektivisering med de metoder som används i rapporten inte nödvändigtvis leder till en energieffektivisering i ett större sammanhang, där primärenergi vägs in.

    Denna rapport är resultatet från Lågan-projektet 2014:12 ”BELOK S – exempel påtillämpning i befintliga småhus”. Projektet är finansierat av Lågan (och därmed indirekt av Energimyndigheten), ByggDialog Dalarna samt Högskolan Dalarna genom Energi- och miljökompetenscentrum, EMC. Även tre banker har bidragit med egen tid i form av deltagande i intervjuer samt synpunkter och dessa är Swedbank Falun, Länsförsäkringar bank Dalarna samt Leksands sparbank.

  • 95.
    Heier, Johan
    et al.
    Dalarna University, School of Technology and Business Studies, Energy Technology.
    Lorenz, Klaus
    Dalarna University, School of Technology and Business Studies, Energy Technology.
    Poppi, Stefano
    Dalarna University, School of Technology and Business Studies, Energy Technology.
    SOHOT: Solvärme för hotell2014Report (Other academic)
    Abstract [sv]

    Vid dimensionering av ett solvärmesystem av den typ som diskuteras i rapporten är varmvattenförbrukningen avgörande för systemets storlek. Litteraturstudien visar dock att varmvattenförbrukningen varierar kraftigt mellan olika typer av hotell samt vilken beläggningsgrad dessa har. För ett normalt ”medel”-hotell kan varmvattenförbrukningen uppskattas till 70 liter vid 60 grader per person och dag. För ett enklare hotell (typ vandrarhem) är förbrukningen ungefär hälften och för ett lyxhotell dubbelt så stor (35 respektive 140 liter per person och dag). Den högsta förbrukningen äger rum under två toppar, en på morgonen och en på kvällen. Under en av dessa toppar används ca 18-30 % av dygnets varmvatten under en timme. Beläggningsgraden är typiskt som högst sommartid och lägre vintertid, men beror förstås på hotellets målgrupp.

     

    Med detta som utgångspunkt har simuleringar för Stockholm och Malaga utförts i Polysun, där tre systemstorlekar samt två kvalitetsklasser av solfångare har använts. Resultaten visar att det går att nå en solandel på 50-75 % av tappvattenlasten i Stockholm och 60-90 % av tappvattenlasten för Malaga. Tack vare den högre solinstrålningen på Malaga kan systemet dimensioneras hälften så stort där. En känslighetsanalys över tappvattenlasten, där samma tappvattenlast som tidigare fast med jämn fördelning över årets månader används, visar att ett system i Nordiskt klimat får en lägre solandel medan systemet i Malaga inte påverkas lika mycket. Samma system i Malaga är alltså mindre känsligt för förändringar i tappvattenlastprofilen.

     

    Aktörsanalysen visar att det finns ett flertal företag i Dalaregionen som kan tänkas vara lämpliga att ingå i en projektgrupp med syfte att ta fram och utveckla en prototyp för konceptet solvärme till hotell. För att välja ut lämpliga samarbetspartners är det en rekommendation att kontakta Teknikdalen i Borlänge. En närmare diskussion med Teknikdalen kan ge en tydligare bild av vilka typer av aktörer som krävs för projektet samt även hur finansieringen kan lösas. Något som bör undersökas vidare är möjligheten till finansiering för ett demonstrationsprojekt, t.ex. lokalt i anknytning till Teknikdalen. En annan möjlig finansiering som verkar vara på gång är en utlysning relaterad till demonstrationsprojekt utomlands. Utlysningen är en enligt kontakt med Teknikdalen en fortsättning på Demomiljö (Sida/Tillväxtverket) dock finns inga detaljer tillgängliga i dagsläget.

  • 96.
    Heinz, Andreas
    et al.
    Institute of Thermal Engineering Graz University of Technology.
    Hengel, Franz
    Institute of Thermal Engineering Graz University of Technology.
    Mojic, Igor
    Institut für Solartechnik SPF Hochschule für Technik HSR.
    Haller, Michel Y.
    Institut für Solartechnik SPF Hochschule für Technik HSR.
    Poppi, Stefano
    Dalarna University, School of Technology and Business Studies, Energy Technology.
    Bales, Chris
    Dalarna University, School of Technology and Business Studies, Energy Technology.
    Matuska, Tomas
    Czech Technical University in Prague, Faculty of Mechanical Engineering.
    Sedlar, Jan
    Czech Technical University in Prague, Faculty of Mechanical Engineering.
    Petrak, Jiri
    Czech Technical University in Prague, Faculty of Mechanical Engineering.
    Final report on heat pump developments in WP 4 - MacSheep Deliverable 4.4: MacSheep -New Materials and Control for a next generation of compact combined Solar and heat pump systems with boosted energetic and exergetic performance2015Report (Other (popular science, discussion, etc.))
  • 97.
    Henning, Annette
    Dalarna University, School of Technology and Business Studies, Energy Technology.
    Indoor climate agreements in energy-efficiency and renovation projects - a question of justice?2018In: Proceedings of the Ises Eurosun 2018 Conference - 12th International Conference on Solar Energy for Buildings and Industry / [ed] Haberle A, 2018, p. 1694-1703Conference paper (Refereed)
    Abstract [en]

    One of the global dilemmas of our time is the urgent need to reduce energy demand in some parts of the world and at the same time manage to increase and improve energy services in others. This paper calls attention to the importance of also recognizing local energy dilemmas and pockets of more vulnerable groups in energy efficiency and building renovation projects. Interviews with tenants in a Swedish ‘million-program’ housing area are used to illustrate the arguments in the paper. Results show essential variations in male and female thermal sensation. They also show little compatibility between the tenants’ wishes for a comfortable home and the housing company’s energy saving ambitions. The paper argues that the use of generalized indoor climate agreements needs to be taken less for granted and complemented with qualitative investigations of all main actors in a specific local context. Only then can possible disparities become evident, and alternative, more just, solutions be worked out.

  • 98.
    Henning, Annette
    Dalarna University, School of Technology and Business Studies, Energy Technology.
    Making Energy Interventions more Effective: Situation, Interaction, and Precondition2015In: International Journal of Humanities and Social Science, ISSN 2220-8488, E-ISSN 2221-0989, Vol. 5, no 9, p. 46-54Article in journal (Refereed)
    Abstract [en]

    A main purpose of this paper is to propose to policy makers, building professionals, and other non-social scientists a way to make energy interventions more culturally informed and, thereby, more effective. The case study on house purchasers gives an ample illustration of the richer results that can be achieved by paying attention to three aspects of energy efficiency initiatives: the contexts and situations of choice in each particular case, the interaction among relevant social actors, and the culture-specific preconditions for choice. Research on how purchasers of new pre-fabricated houses in Sweden choose their heating system show how such decisions tend to fall between two stools. Furthermore, the organizational structure of housing companies frames house purchasers' decision making. An important result is that energy saving or conversion measures must be promoted at an early stage amongst those who plan and construct buildings (rather than later amongst dwellers and energy end users).

  • 99.
    Henning, Annette
    et al.
    Dalarna University, School of Technology and Business Studies, Energy Technology.
    Sattari, Amir
    Dalarna University, School of Technology and Business Studies, Construction.
    Evaluating thermal comfort in a Swedish block of flats: A methodological comparison2017Conference paper (Refereed)
    Abstract [en]

    Two methodological approaches have been used to investigate thermal comfort amongoccupants in a Swedish block of flats; measurements and thermal comfort standards on the onehand, and qualitative interviews on the other. The purpose with this paper is to present, compareand discuss results from these two radically different methods. The results coincide concerningvariations of thermal comfort throughout the day, but are much less in accord in results whereoccupants express, or are presumed to complain of, thermal discomfort. The interviews showthat female occupants tend to suffer more from thermal discomfort than male occupants, a resultwhich is absent in the measurement methodology. The results give support to suggestions thatgender aspects should be taken more into account when determining and controlling thermalcomfort. The differing results also point at the importance of complementing standardizedthermal comfort measurements with surveys or qualitative interviews.

  • 100.
    Hernandez Velasco, Marco
    et al.
    Dalarna University, School of Technology and Business Studies, Energy Technology.
    Fiedler, Frank
    Dalarna University, School of Technology and Business Studies, Energy Technology.
    Timm, Dirk
    juwi Solar GmbH.
    Weak light performance efficiency in installed pv-arrays of different module technologies2014In: 29th European Photovoltaic Solar Energy Conference and Exhibition Proceedings, 2014, p. 2515-2522Conference paper (Other academic)
    Abstract [en]

    This work analyses the weak light performance efficiency of six different free field and grid-connected PVarrays of various module technologies (mc-Si, CIGS, CdTe). The installed capacities per array range from 1,8kWp to 2,2kWp. The studied systems are located at the same site in Germany and are mounted on a ventilated and shaded-free structure. The irradiance was measured with both a pyranometer and a c-Si reference cell oriented at the plane of the array. Besides the weather conditions, the arrays share a similar system configuration (same inverter model, rack type and orientation, temperature sensors, etc.) making their results highly comparable. The data collected comprised 312 days from September 2011 until July 2012. When analyzing the data points at moments of low irradiance (< 800W/m2), a high dispersion was found which is most likely due to optical effects, different spectral distributions and changing module temperatures. To reduce the optical and spectral effects, a series of data filters were applied to limit the points used (Air Mass ≤4 and Angle of Incidence ≤50°). To compensate for the temperature effects and translate the values to STC (25°C), five different methods were assessed. The Procedure 2 of the IEC 60891 was considered the most suitable due to its relative simplicity, availability of parameters in the datasheets, good accuracy even with missing values, and the potential to improve the results when the complete set of inputs is available. The final analysis of the weak light performance showed no clear superiority of any particular PV-technology. From the results of this study, an overall advantage of thin-film over crystalline modules cannot be anymore concluded.

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