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  • 101. Hu, J
    et al.
    Chen, W
    Yin, Y
    Li, Y
    Yang, D
    Wang, H
    Zhang, Xingxing
    Dalarna University, School of Technology and Business Studies, Energy Technology.
    Electrical-thermal-mechanical properties of multifunctional OPV-ETFE foils for transparent membrane buildings2018In: Polymer testing, ISSN 0142-9418, E-ISSN 1873-2348, Vol. 66, p. 394-402Article in journal (Refereed)
    Abstract [en]

    ETFE (ethylene tetrafluoroethylene) foils integrated organic photovoltaic cells (OPV) have attracted considerable attention in recent years due to the achievement of sustainability. As building materials, multifunctional OPV-ETFE foils could produce electricity, store thermal energy and possess structural capability. In this case, electrical, thermal and mechanical properties coexist and influence each other due to photovoltaic/thermal effects. Understanding the fundamental mechanism is significant to analyze and design corresponding structures. This paper concerns coupled properties of OPV-ETFE specimens with controlled experiments. One-parameter and two-parameter analysis of two typical specimens are performed to investigate essential properties. Experimental observations show that within normal working conditions, electrical properties are relatively independent but that thermal-mechanical properties are related to each other. Yield stress, yield strain and elastic modulus are calculated from stress-strain curves; these mechanical properties are comparable with those of original ETFE foils at the same temperature. It is concluded from temperature-stress curves that yield point has a critical effect on temperature-stress correlation and that mechanical properties of double OPV specimens are better than those of single OPV specimens. Generally, these mechanical properties could provide basic insights into evaluation of energetic performance and structural behavior of transparent membrane buildings.

  • 102. Huang, P
    et al.
    Fan, C
    Zhang, Xingxing
    Dalarna University, School of Technology and Business Studies, Energy Technology.
    Wang, J
    A hierarchical coordinated demand response control for buildings with improved performances at building group2019In: Applied Energy, ISSN 0306-2619, E-ISSN 1872-9118, Vol. 242, p. 684-694Article in journal (Refereed)
  • 103.
    Johansson Macedo, Liv May
    Dalarna University, School of Technology and Business Studies, Energy Technology.
    Modification of a Moving Bed Biofilm Reactor(MBBR) due to radically changed process conditions: A case study of Kvarnsveden paper mill2018Independent thesis Advanced level (degree of Master (Two Years)), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Papermaking process require large amounts of energy and water; therefore, pulp and paper

    mills can be potentially very polluting. The wastewater resulting from the papermaking

    process must be carefully managed as it is very rich in dissolved organic matter and contain

    compounds that make it difficult to treat. MBBR technology emerged as a possibility to

    increase the treatment capacity and to make more compact treatment systems designed to

    remove high organic loads, since in addition to having biomass in suspension as the

    activated sludge process, also has biomass adhered to plastic supports. This research was

    commissioned by Stora Enso Kvarnsveden and emerged in need of a bioreactor

    modification due to reduction of the wastewater load after the closure of PM11 in 2013 and

    PM8 in 2017. An evaluation of the performance of bioreactors is necessary with possible

    results to only run one bioreactor in the future and save energy. For performance analysis,

    two weeks of measurements were performed, one with the two bioreactors running at the

    same time and one with only K150 reactor running, trying to simulate what happens if one

    of them is stopped. Analysis of the main operating parameters of the MBBR system were

    evaluated during this research. As result, it was recommended an action to remove the

    excess of adhered biomass and an increase of the filling rating to 50%, in order to optimize

    TOC reduction.

  • 104.
    Johari, Fatemeh
    Dalarna University, School of Technology and Business Studies, Energy Technology.
    Predictive Control Strategies for aHeat Pump System with PV and Electrical Storage with Various Boundary Conditions2018Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    The idea of nearly zero energy building (nZEB) has been emerged from the global trend toward reduction in fossil fuel consumption and green-house gas emission. In spite of different definitions for nZEB, it is vastly known as a grid connected building with highly reduced energy consumption by means of on-site renewable energy production. Accordingly, heat pumps are one of the remarkably efficient heating and cooling technologies considered as the promising components of the nZEBs, specially, when they are associated with the renewable energy systems. However, due to the interaction between heat pump, PV and the grid, the efficiency and the electrical self-consumption of the system strongly depend on the advanced controller strategies such as predictive controllers using price and weather forecast services. Although design of the control algorithms is a very challenging procedure, evaluation of the functionality of these defined algorithms is of paramount importance as well.In this thesis, the robustness of the pre-defined price and weather predictive controllers is studied by testing the performance of a heat pump system for different boundary conditions and compare the results with a reference case study. The base case is a heat pump system for a single-family house with the total heating floor area of 143 m2 and the annual heating demand of 100 kWh/m2.year. The building is located in Norrköping, Sweden and it is assumed that a family of 4 (parents and 2 children) are living in the house. The associated 5.7 kW PV system is mounted on the south oriented roof with the slope of 27˚. Moreover, the system has a storage tank with the total capacity of 180 liter for DHW and a 7.2 kWh battery bank increases the amount of harvested solar energy.The identified methodology of this thesis suggests evaluating the system for the range of variables and boundary conditions, included the climate, thermal properties of the building, orientation and slope of the roof of the building, room set temperature and the occupancy of the building which leads to the various DHW and electricity load profile. Moreover, to study the influences of the controllers on the system, a group of performance indicators are defined. PV self-consumption, solar fraction, final energy use, annual net cost of electricity and seasonal performance factor of the system are considered as the key figures of this study. Next, it aims to do the sensitivity analysis of the system with and without controllers under various boundary conditions. For this purpose, the TRNEdit, as one of the TRNSYS tools which is extended purposely to edit TRNSYS files and manage the parametric simulation studies, is used. Finally, the results from the parametric studies of the system is evaluated to examine the robustness of the controllers.Consequently, the acquired results from the sensitivity analysis of the system with the introduced predictive controllers proves that the performance of the system successfully promotes when it utilizes predictive strategies of PV generation and electricity price. However, the suggested control algorithms need to be slightly modified in order to achieve better results when they operate simultaneously.

  • 105. Joly, M.
    et al.
    Ruiz, G.
    Mauthner, F.
    Bourdoukan, P.
    Emery, M.
    Andersen, Martin
    Dalarna University, School of Technology and Business Studies, Energy Technology.
    A methodology to integrate solar thermal energy in district heating networks confronted with a Swedish real case study2017In: Energy Procedia, ISSN 1876-6102, E-ISSN 1876-6102, Vol. 122, p. 865-870Article in journal (Refereed)
    Abstract [en]

    Among other solutions, the integration of solar energy in district heating networks can contribute significantly to the increase of the renewable energy fraction in an urban area. This article describes the methodology developed in the framework of IEA Task 52 to help stakeholders during early phases of new or refurbishments projects. This methodology integrates a tool which is capable to assess the main solar indicators of the project with only two inputs: the solar installation area and the building heated area. The tool outputs are compared to the measured values of a Swedish case study.

  • 106.
    Joudi, Ali
    Dalarna University, School of Technology and Business Studies, Energy Technology. Linköpings universitet.
    Radiation properties of coil-coated steel in building envelope surfaces and the influence on building thermal performance2015Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Recent studies have shown that the optical properties of building exterior surfaces are important in terms of energy use and thermal comfort. While the majority of the studies are related to exterior surfaces, the radiation properties of interior surfaces are less thoroughly investigated. Development in the coil-coating industries has now made it possible to allocate different optical properties for both exterior and interior surfaces of steel-clad buildings. The aim of this thesis is to investigate the influence of surface radiation properties with the focus on the thermal emittance of the interior surfaces, the modeling approaches and their consequences in the context of the building energy performance and indoor thermal environment.

    The study consists of both numerical and experimental investigations. The experimental investigations include parallel field measurements on three similar test cabins with different interior and exterior surface radiation properties in Borlänge, Sweden, and two ice rink arenas with normal and low emissive ceiling in Luleå, Sweden. The numerical methods include comparative simulations by the use of dynamic heat flux models, Building Energy Simulation (BES), Computational Fluid Dynamics (CFD) and a coupled model for BES and CFD. Several parametric studies and thermal performance analyses were carried out in combination with the different numerical methods.

    The parallel field measurements on the test cabins include the air, surface and radiation temperatures and energy use during passive and active (heating and cooling) measurements. Both measurement and comparative simulation results indicate an improvement in the indoor thermal environment when the interior surfaces have low emittance. In the ice rink arenas, surface and radiation temperature measurements indicate a considerable reduction in the ceiling-to-ice radiation by the use of low emittance surfaces, in agreement with a ceiling-toice radiation model using schematic dynamic heat flux calculations.

    The measurements in the test cabins indicate that the use of low emittance surfaces can increase the vertical indoor air temperature gradients depending on the time of day and outdoor conditions. This is in agreement with the transient CFD simulations having the boundary condition assigned on the exterior surfaces. The sensitivity analyses have been performed under different outdoor conditions and surface thermal radiation properties. The spatially resolved simulations indicate an increase in the air and surface temperature gradients by the use of low emittance coatings. This can allow for lower air temperature at the occupied zone during the summer.

    The combined effect of interior and exterior reflective coatings in terms of energy use has been investigated by the use of building energy simulation for different climates and internal heat loads. The results indicate possible energy savings by the smart choice of optical properties on interior and exterior surfaces of the building.

    Overall, it is concluded that the interior reflective coatings can contribute to building energy savings and improvement of the indoor thermal environment. This can be numerically investigated by the choice of appropriate models with respect to the level of detail and computational load. This thesis includes comparative simulations at different levels of detail.

  • 107.
    Joudi, Ali
    et al.
    Dalarna University, School of Technology and Business Studies, Energy Technology. SSAB Europe, Borlänge.
    Cehlin, Mathias
    Högskolan i Gävle.
    Svedung, Harald
    Dalarna University, School of Technology and Business Studies, Energy Technology. SSAB Europe, Borlänge.
    Rönnelid, Mats
    Dalarna University, School of Technology and Business Studies, Energy Technology.
    Moshfegh, Bahram
    Högskolan i Gävle.
    Numerical and experimental investigation of the influence of infrared reflective interior surfaces on building temperature distributions2017In: Indoor + Built Environment, ISSN 1420-326X, E-ISSN 1423-0070, Vol. 26, no 3, p. 355-367Article in journal (Refereed)
    Abstract [en]

    Radiative properties of interior surfaces can affect not only the building heat flux but also the indoor environment, the latter of which has not been thoroughly investigated. The aim of this study is to analyse the effect of surface emissivity on indoor air and surface temperature distributions in a test cabin with reflective interior surfaces. This was done by comparing experimental and simulation data of the test cabin with that of a normal cabin. This study employs transient computational fluid dynamics (CFD) using re-normalisation group (RNG) k–" model, surface-to-surface radiation model and an enhanced wall function. Boundary conditions were assigned to exterior surfaces under variable outdoor conditions. The numerical and the measurement results indicate that using interior reflective surfaces will affect the indoor air temperature distribution by increasing the vertical temperature gradient depending on the time of the day. CFD simulations with high spatial resolution results show increased interior surface temperature gradients consistent with the increased vertical air temperature gradient. The influence of reflective surfaces is potentially greater with higher indoor surface temperature asymmetry. The vertical indoor air temperature gradient and surface temperatures are important parameters for indoor thermal comfort.

  • 108.
    Khadra, Alaa
    Dalarna University, School of Technology and Business Studies, Energy Technology.
    Economic Performance Assessment of Three Renovated Multi-Family Houses with Different HVAC Systems2018Independent thesis Advanced level (degree of Master (Two Years)), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Since the building sector is responsible for 40% of the energy consumption and 36% of

    CO2 emissions in the EU, the reduction of energy use has become a priority in this sector.

    The EU has adopted several policies to improve energy efficiency. One of these policies

    aims to achieve energy efficient renovations in at least 3% of buildings owned and

    occupied by governments annually. In Sweden, a large part of existing buildings was built

    between 1965 and 1974, a period commonly referred to as ‘miljonprogrammet’. Stora

    Tunabyggen AB, the public housing company in Borlänge municipality, begun a

    renovation project in the Tjärna Ängar neighborhood within the municipality with the

    greatest share of its buildings stock from this period. The pilot project started in 2015. The

    aim of this project was to renovate three buildings with similar measures, that is, by

    adding 150 mm attic insulation, replacing windows with higher performing ones (U-value

    1 W/m

    ²K), by adding 50 mm of insulation to the infill walls and by the installation of flowreducing

    taps. The essential difference between the three renovation packages is the

    HVAC systems. The selected HVAC systems are (1) exhaust air heat pump, (2) mechanical

    ventilation with heat recovery and (3) exhaust ventilation. Life cycle cost analysis was

    conducted for the three building and sensitivity analysis for different values of discount

    rate and energy price escalation was performed. The study found that the house with

    exhaust ventilation has the lowest life cycle cost and the highest energy cost. The house

    with exhaust air heat pump has 3% higher life cycle cost and 18% lower energy use at 3%

    discount rate and 3% energy price escalation. The study found that mechanical ventilation

    with heat recovery is not profitable, although it saves energy. The sensitivity analysis has

    shown that the possible increment of price energy and lower discount rate give higher

    value for the future costs in life cycle cost analysis. This lead to the main finding of this

    thesis, which is that exhaust air heat pump is the best choice for the owner according to

    the available data and the assessed parameters.

  • 109.
    Korde, Anukool
    Dalarna University, School of Technology and Business Studies, Energy Technology.
    Assessment of a Solar PV Re-Powering Project in Sweden Using Measured and Simulated Data2017Independent thesis Advanced level (degree of Master (Two Years)), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Re-powering solar PV plants is an upcoming discussion on the global stage. Although the respective component warranties indicate the time to change the system machinery, the methodology and justification for carrying this out are two aspects that need further study.

    The rooftop solar PV system on top of Dalarna University was re-positioned in 2014. Prior to installing the system in its new position, the system arrays were reconfigured and new inverters were installed.

    This thesis aimed to compare and analyze two sections of the solar power plant to understand which amongst them performs better. Graphs depicting energy, current, voltage and other parameters were formulated to ascertain the efficacy of the array configurations for this Nordic latitude.

    Thereafter, PVsyst and SAM were used to compare the simulated results with the actual output from the system.

    It was found that the measured energy output from one section of the solar power plant was higher than that of the other during 2014. On an annual basis, this difference was 21.5 kWh or 2%. On closer inspection, this contrast was attributed to a difference in yield early in the morning.

    Further, PVsyst simulated the annual energy with a deviation of less than 1% than what was measured, whereas SAM measured a deviation in energy measurement of 2.5% higher than the actual measured energy. These values were obtained using the detailed design options for both softwares. A point to keep in mind is that prior experience of working with both these softwares is recommended prior to carrying out the simulations on these softwares.

    An underlying point to note in this study is its limitations. This study is valid in the northern latitudes, such as the Nordic climates, since other regions would not have such low (sub-zero) temperatures to account for while sizing the inverter. In regions of high irradiance, a system re-powered in a way such as the system in this case would have higher clipping losses.

    Relevant previous studies and related topics have been visited, summarized and cited.

  • 110.
    Kuhn, Tillmann
    et al.
    Fraunhofer ISE.
    Fath, Karoline
    Fraunhofer ISE.
    Bales, Chris
    Dalarna University, School of Technology and Business Studies, Energy Technology.
    Gustafsson, Marcus
    Dalarna University, School of Technology and Business Studies, Energy Technology.
    Nouvel, Romain
    ZAFH.
    Fedrizzi, Roberto
    EURAC.
    D2.3 RES availability survey and boundary conditions for simulations2014Report (Other academic)
  • 111.
    Kumar, Pankaj
    Dalarna University, School of Technology and Business Studies, Energy Technology.
    Performance Evaluation of High Temperature Steam Generating Solar Collectors2016Independent thesis Advanced level (degree of Master (Two Years)), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    The Absolicon Company in Härnösand have developed a solar collector field with high performance parabolic solar collectors to generate high temperature steam of around 160°C which could be directly used for industrial application. This project work involves thermal and optical performance evaluation of the collector field to check the collector performance.

    The solar collector field is set up in Härnösand, Energy Park; the collector field consists of 8 parabolic solar collectors with a sun tracking mechanism. The sun tracking is provided by 4 different actuators. The parabolic collectors are imaging type and line focus. The heat transfer fluid is circulated through the collector circuit with the help of a variable flow pump, which varies its flow rate based on the solar irradiation values.

    This project work includes, conducting the literature review and developing a test rig for testing of the collector field as per the EN12975 standards, 2006 (steady state testing) for solar collector testing. The thermal and optical performance evaluation of the collector field has to be evaluated along with the determination of the radiative, conductive and convective heat loss coefficients.

    In the test work, the thermal performance is determined by measuring the heat energy gained by the heat transfer fluid (HTF) in the system on a clear sunny day at solar noon period. The heat loss coefficients are calculated by circulating a constant temperature HTF into the collector circuit as per the EN12975, (2006) standards and then curve tracing was done to obtain the value of heat loss coefficients. The peak optical efficiency was determined by testing the collector at solar noon period under steady state conditions as per the standards.

    Matlab simulation analysis was also performed as a part of this project work to check the effect of changing incidence angle of solar radiation on the solar collector surface to determine the IAM for the collector field. Effects on the results were also determined due to the sensor errors and sensitivity analysis of the system was also performed.

  • 112.
    Kurdia, Ali
    Dalarna University, School of Technology and Business Studies, Energy Technology.
    Consequences of Nordic Conditions on the Performance of Large-Scale Building Applied PV Installations2017Independent thesis Advanced level (degree of Master (Two Years)), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    This thesis aimed for a better understanding of the Nordic weather conditions in terms of snow induced soiling on the performance and production of an established photovoltaic plant located on the roof of Økern nursing home, Oslo.

    In order to realize the main aim, several steps had to be done in preparation of the main analysis, these steps in fact are as important to this thesis as the main deliverable.

    The search for appropriate meteorological data proved to be not an easy task because of the scarcity of ground measurement stations, and the high inaccuracies in satellite observations.

    After analyzing all the sources with available data for the region of Oslo, three sources of data were chosen based on comparisons to an onsite set of reference measurements, these are the Blindern meteo station, the NASA SSE satellite derived observations, and the STRANG data base.

    A model of the actual system was created in PVsyst, exceptional attention to the level of detail was exercised in order to approach the case of eliminating any source of variation in the simulated models other than the required study parameter, the soiling.

    Simulations of many system variants ultimately resulted in the aggregation of a soiling loss profile to be used in conjunction with each of the meteo sources to predict the snow induced soiling consequences on the system.

    The soiling loss profiles were tested and the results compared to actual system production measurements, and it was successful in introducing the correction the model needed to simulate the system closely to reality.

    However, absolute change in production figures is relatively small, therefore, this study and any future continuation of it is oriented into research and improvement as it possess minimal impact on a commercial application.

  • 113. Kántor, Noémi
    et al.
    Chen, Liang
    Gál, Csilla V
    Dalarna University, School of Technology and Business Studies, Energy Technology.
    Human-biometeorological significance of shading in urban public spaces: Summertime measurements in Pécs, Hungary2018In: Landscape and Urban Planning, ISSN 0169-2046, E-ISSN 1872-6062, Vol. 170, p. 241-255Article in journal (Refereed)
    Abstract [en]

    Shading is shown to be one of the most effective strategies to mitigate urban heat stress, especially on a small scale. This paper presents an empirical study investigating the effectiveness of different means of shading—by sun sails and trees—to improve the local thermal environment during the summer. Three different urban settings were investigated through detailed human-biometeorological measurements in the Hungarian city of Pécs. Our study employed the accurate six-directional radiation measurement technique, and calculated Physiological Equivalent Temperature (PET) from the obtained data to assess outdoor thermal conditions. Our results indicate that in open urban squares trees can mitigate heat stress more effectively than low-hanging sun sails, installed right above the head of pedestrians. In the period of 9:00–16:00, the average PET reduction by trees and low sun sails was 9.0 °C and 5.8 °C, respectively. Sun sails, installed at higher elevation to shade an entire street canyon, and mature trees with dense canopy had more pronounced heat stress reduction ability, and were able to reduce the local PET by over 10 °C. Our study demonstrates the importance of detailed small-scale field measurements, the outcomes of which can be incorporated into climate-responsive urban design strategies with ease.

  • 114.
    Kántor, Noémi
    et al.
    University of Szeged, Szeged, Hungary.
    Gulyás, Ágnes
    University of Szeged, Szeged, Hungary.
    Gál, Csilla V
    Dalarna University, School of Technology and Business Studies, Energy Technology.
    Mikroklíma modellezés a városi közterülettervezés szolgálatában [Microclimate modeling at the service of urban public space design]2017In: 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]

    Európa lakosságának mintegy kétharmada már most is városi környezetben él, s a városi populáció aránya 2050-re várhatóan 80% fölé fog emelkedni. Mivel a városokra jellemző többlet hőmennyiség, valamint a városok csökkent átszellőzési képessége tovább súlyosbítják a klímaváltozással járó hőmérsékletemelkedést, a – várhatóan egyre gyakoribbá, hosszabbá és intenzívebbé váló – hőhullámok hatásai különösen a városlakók egészségét veszélyeztetik. Ennél fogva a nyári hőség káros következményeinek megelőzése a várostervezés egyik kiemelt feladata. A természet- alapú megoldások (Nature-Based Solutions, NBS) egy újonnan bevezetett fogalom a környezetkutatás és környezet- gazdálkodás területén, mely a klímaváltozással járó kihívások kezelésére természetes tényezőket, illetve folyamatokat ajánl. Ebben a tanulmányban – a négyéves Nature4Cities projekt keretein belül – a fás vegetáció hőstressz-mérséklő kapacitását vettük górcső alá egyrészt terepi mérések, másrészt numerikus szimulációk segítségével.A léghőmérséklet korántsem az egyedüli paraméter az emberi szervezet hőháztartása szempontjából. Sőt, számos humán-biometeorológiai tanulmány rámutatott már a sugárzási viszonyok vezető szerepére a nyári hőterhelés kialakulásában. Éppen ezért tanulmányunkban a biometeorológiai vizsgálatok kulcsparaméterére, az átlagos sugárzási hőmérsékletre (Mean Radiant Temperature, Tmrt), illetve ennek a fás vegetáció általi mérséklésére helyeztük a hangsúlyt.Tanulmányunk első részében három, a város-biometeorológia területén gyakran alkalmazott mikroklíma modellt (RayMan, ENVI-met, SOLWEIG) hasonlítottunk össze a tekintetben, hogy mennyire képesek a Tmrt valós értékeinek szimulálására. A modellellenőrzéshez egy derült égboltviszonyokkal jellemezhető késő nyári nap humán- biometeorológiai méréssorozatának adatait használtuk fel. A 26-órás mérés során a szegedi Bartók Béla tér öt különböző pontján rögzítettük a rövid-, és hosszúhullámú sugárzási mérleg komponenseket, hogy azokból a leghitelesebb biometeorológiai eljárás szerint Tmrt-t számoljunk. A három mikroklíma-modell közül a SOLWEIG szolgáltatta a leghitelesebb eredményeket, így később ezt a modellt használtuk arra, hogy összehasonlítsuk különféle fásítási szcenáriók hőstressz-mérséklő hatását – ugyancsak a szegedi Bartók Béla téri mintaterületen. A szimulációk alapján a lombkorona transzmisszivitásának (sugárzásáteresztő képességének) változtatása kisebb, míg azonos korona-térfogat mellett a lombkorona méretének (több kis fa vs. kevesebb nagyobb fa), valamint a fák területen belüli elrendezésének változtatása (egyenletesen vs. csak az épülethomlokzatok mentén ültetett fák) jelentősebb Tmrt módosítást eredményezett.

  • 115. Kántor, Noémi
    et al.
    Gulyás, Ágnes
    Gál, Csilla V
    Dalarna University, School of Technology and Business Studies, Energy Technology.
    Relevance of urban trees and sun shades regarding summertime heat stress reduction – a field surveys from Pécs, Hungary2017Conference paper (Refereed)
    Abstract [en]

    Mitigating the impact of summertime heat stress became the central issue of climate-conscious urban planning as a result of rising temperatures and continued urbanization trends. Furthermore, recent EU planning directives gave priority to nature-based solutions (NBS) and hence to re-naturing cities. Within the scope of the international Nature4Cities project fostering the use such solution, an inter- and cross-disciplinary research will be done assessing the performance of archetypal NBSs addressing different urban challenges – in this case, heat mitigation in urban environments.The objective of this particular study is to compare the effectiveness of natural and artificial shading solutions (urban trees and sun sails) in reducing summertime heat stress and enhancing outdoor thermal comfort of pedestrians. The Physiological Equivalent Temperature (PET), used as performance indicator in this study, was calculated from field data. The measurement campaign utilizing two human-biometeorological stations recorded pedestrian-level radiant flux densities from six perpendicular directions, air temperature, relative humidity and wind speed on three late-summer days. The daytime measurements were conducted at three different urban settings in Pécs, a medium-size Central-European city.Our research found that mature trees with dense canopy have the highest heat stress reduction potential and could reduce the local PET by up to 10°C. Even though artificial sun sails blocked effectively direct solar exposure, the low-hanging sun sails became the sources of long-wave radiation which made the thermal comfort conditions below them somewhat worse compared to trees. Our study demonstrates the importance of small-scale field measurements, the outcomes of which are directly applicable in the climate-adaptive design of urban spaces.

  • 116. Kántor, Noémi
    et al.
    Gál, Csilla V
    Dalarna University, School of Technology and Business Studies, Energy Technology.
    Gulyás, Ágnes
    The impact of façade orientation and vegetation on summer heat stress – measurements and simulations from a rectangular Central-European square2017Conference paper (Refereed)
    Abstract [en]

    Around three quarter of the European population already lives in urban areas and by 2050 this proportion isexpected to rise over 80%. Since climate change is expected to bring rising temperatures and more frequent heatwaves, mitigating the impact of extreme heat events is one of the most important issues in urban planning. Nature-Based Solutions (NBS) is a recently introduced concept in environmental research and management that promotesnature as a means to address the challenges brought about climate change. Researches of human-biometeorologydemonstrated that radiation heat load, quantified as mean radiant temperature (Tmrt), is the main source ofdaytime heat stress in summer. In European cities—especially in those with dense historic urban cores—carefullyplanned and properly maintained shade trees constitute the most effective NBS for mitigating extreme thermalconditions, while also offering several co-benefits.This study was conducted with the following two aims: (a) to assess the impact of woody vegetation anddifferent façade orientation on the radiation heat load in a complex urban setting; and (b) to evaluate the performanceof SOLWEIG, a radiation model, in reproducing the measured short- and long-wave radiation flux densities.The observation was conducted over a 26-hour long period at the rectangular Bartók Square in Szeged (Hungary)on a clear and warm late-summer day. The investigation utilized two tailor-made human-biometeorologicalstations equipped with rotatable net radiometers. The model–measurement comparison is based on data collectedfrom five locations within the square: from the center and from four sites next to the bordering façades.The measurements confirmed that on clear summer days Tmrt can reach extreme level at exposed locations(65–75C). However, shade trees are able to reduce daytime Tmrt to 30–35C. Shading SE-, S- and SW-facingfaçades and adjacent sidewalks is extremely important for the reduction of pedestrian heat stress and thus, therisk of heat stroke. When a measurement point adjacent to a facade became exposed to direct solar radiation,the radiation load increased significantly due to the additional lateral components—the reflected short-wave andthe emitted long-wave fluxes—emanating from the wall. In this respect, SOLWEIG was unable to reproducethe prolonged heat emitting effect of walls following solar exposure. Additionally, the measurement–modelcomparison revealed minor inconsistencies that originated from the model’s treatment of tree crowns: representingthem as perfectly shaped and homogeneous bodies. Due to this simplification, the observed brief penetrations ofdirect sunbeams through the canopy at most locations were not reproduced.

  • 117. Kántor, Noémi
    et al.
    Gál, Csilla V
    Dalarna University, School of Technology and Business Studies, Energy Technology.
    Gulyás, Ágnes
    Unger, János
    The impact of façade orientation and woody vegetation on summertime heat stress patterns in a Central-European square: comparison of radiation measurements and simulations2018In: Advances in Meteorology, ISSN 1687-9309, E-ISSN 1687-9317, article id 2650642Article in journal (Refereed)
    Abstract [en]

    Increasing summertime air temperature deteriorates human health especially in cities where the warming tendency is exacerbated by urban heat island. Human-biometeorological studies shed light on the primary role of radiation conditions in the development of summertime heat stress. However, only a limited number of field investigations have been conducted up to now. Based on a 26-hour long complex radiation measurement this study presents the evolved differences within a medium-sized rectangular square in Szeged, Hungary. Besides assessing the impact of woody vegetation and façade orientation on the radiation heat load, different modeling software (ENVI-met, SOLWEIG, RayMan) are evaluated in reproducing mean radiant temperature (Tmrt).Although daytime Tmrt can reach extreme level at exposed locations (65–75°C) mature shade trees can reduce it to 30–35°C. Nevertheless, shading from buildings adjacent to sidewalks plays also an important role in mitigating pedestrian heat stress. Sidewalks facing to SE, S and SW do not benefit from the shading effect of buildings therefore shading them by trees or artificial shading devices is of high importance. The measurement–model comparison revealed smaller or larger discrepancies that raise awareness on the careful adaptation of any modeling software and on the relevance of fine-resolution field measurements.

  • 118.
    Lang, Markus
    Dalarna University, School of Technology and Business Studies, Energy Technology.
    Performance Study of a PVT Air Collector2016Independent thesis Advanced level (degree of Master (Two Years)), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    PVT collectors are more and more in focus as they combine electricity generation and generation of heat in one single collector. In this thesis a thin film CIGS PV module is used to replace a conventional solar absorber and create an air ventilated PVT collector. The thesis includes the design and construction of the collector, measurement of important performance parameters as well as analysis of the collected data in terms of thermal and electrical performance.

    A Solibro CIGS PV module is used as solar absorber and a wooden box is constructed around the module. An electric fan is used to control air flow behind the PV module. Inlet and outlet air temperatures of the collector are measured as well as the temperatures of the backside of the PV module and the opposite wall in the air channel and logged together with irradiance level every ten seconds during a period of one week.

    During the measurement period with clear sky conditions quite constant irradiance levels can be measured resulting in a temperature increase between inlet and outlet air temperature of 22 °C. PV module temperatures reached values up to 60 °C while the outlet temperature reached 45 °C. Thermal power reached values above 300 W/m² and efficiency was calculated to 0.33 for high periods with high irradiance (900 W/m).

    Infrared images of the collector show that the heat distribution on the PV module was quite uniform which means that also air flow behind the module can be considered uniformly distributed. Only a small area around the air inlet showed slightly lower temperature levels compared to the opposite side at the same level.

    Electrical performance was analyzed theoretically by comparing output levels under conditions of forced ventilation and with natural ventilation. The temperature difference achieved by the cooling effect on the module by the forced airflow accounted for an increase of about 6 % of power output. In absolute numbers however the needed power for the fan is higher compared to the gain in electricity output from the 100 Wp PV module.

    It can be seen that measured outlet temperatures were slightly delayed compared to corresponding irradiance levels and the temperature changes are less fluctuating thus smoothened compared to the fast changing irradiance values. Pressure drop in the collector is a limiting factor that requires a minimum air gap diameter for a certain airflow.

    Using a CIGS PV module is a suitable option to replace a conventional absorber in a solar collector if the benefit from the produced electricity is of use and maximum thermal output is not the major concern. To achieve higher temperatures air flow needs to be decreased which will have a negative impact on the total electricity output.

    In terms of using such a collector for solar drying it depends on the prevailing climate conditions if desired temperature levels can be reached. The electricity produced by the PV module could directly be used to power an electric fan and in a further step could open for the option to control air flow and air temperature into the drying chamber.

  • 119.
    Leidi, Johan
    Dalarna University, School of Technology and Business Studies, Energy Technology.
    The exchange-value of solar thermal energy2007In: ISES Solar World Congress 2007, ISES 2007, 2007, Vol. 4, p. 2961-2965Conference paper (Refereed)
    Abstract [en]

    In Sweden there is a tendency that alternative energy will develop on market premises. In this paper I suggest that the low exergy value of solar thermal heat limits the technique's commodification, i.e. the possibility of having a commercial exchange-value on the market. Anthropologists argue that value of a commodity has to be related to social and cultural aspect of the society where it is situated. By applying anthropological theories of value on solar thermal energy I propose that we also need to include the solar thermal energy's physical conditions to understand its potential of becoming a commodity in the society where it is supposed to produce action.

  • 120.
    Leijonhufvud, Gustaf
    et al.
    Högskolan på Gotland, Uppsala universitet.
    Henning, Annette
    Dalarna University, School of Technology and Business Studies, Energy Technology.
    Rethinking indoor climate control in historic buildings: The importance of negotiated priorities and discursive hegemony at a Swedish museum2014In: Energy Research & Social Science, ISSN 2214-6296, Vol. 4, p. 117-123Article in journal (Refereed)
    Abstract [en]

    Much effort has in recent years been directed to support sustainable indoor climate control strategies in historic buildings. In this paper we show the necessity to complement the dominant technical approaches with research that take a wider interest in specific contexts, social practicies, and negotiated decisions. The objective of the paper is to illustrate how the interactions between perceptions and experiences of different professional groups are pivotal for the management of the indoor climate. An ethnographic study of decision making in an historic house museum was carried out in 2009 and 2012. Interviews were made with individuals who either took part in management or were affected by the indoor climate. The findings show how discussions among social actors and the way their respective priorities are negotiated are essential features of the management of the indoor climate and have a strong impact on the ability to modify it. It turns out that a hegemonic discourse about preservation as the dominant rationale for indoor climate control in tandem with "acceptable" conditions with respect to preservation have reinforced a state of stability. This explorative study opens up for a re-framing of how a more sustainable management of historic buildings can be achieved.  

  • 121.
    Leppin, Lorenz
    Dalarna University, School of Technology and Business Studies, Energy Technology.
    Development of Operational Strategies for a Heating Pump System with Photovoltaic, Electrical and Thermal Storage2017Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    This study describes the development of operational strategies for an exhaust air heat pump system that supplies space heating and domestic hot water. The system combines photovoltaic power production with two different storage types. These are electrical storage using batteries and thermal storage in using a domestic hot water tank and in form of the thermal capacity of the building. The investigation of the control strategies is carried out for a detailed single family house model in Sweden in the simulation software TRNSYS. The overall aim of the control strategies is to improve the performance of the energy system in terms of self-consumption, self-sufficiency, final energy and seasonal performance factor. Three algorithms are developed and compared to a base case without additional control. The first algorithm only uses the thermal storage in the hot water tank and the building. The second uses only the battery to store the photovoltaic electricity. The third control algorithm combines both storage types, electrical and thermal.

    The simulation results show that for the studied system the energetic improvement is higher with the use of electrical storage compared to using thermal storage. The biggest improvement however is reached with the third algorithm, using both storage types in combination. For the case of a photovoltaic-system with 9 kW and battery store with 10.8 kWh and a 180 l hot water store the self-consumption reaches up to 51% with a solar fraction of 41 %. The reduction in final energy consumption for this case is 3057 kWh (31 %) with the heat pump having a seasonal performance factor of 2.6. The highest self-consumption is reached with a photovoltaic-system of 3 kW and battery store with 3.6 kWh, which comes to 71 %.

  • 122. Li, G.
    et al.
    Tang, L.
    Zhang, Xingxing
    Dalarna University, School of Technology and Business Studies, Energy Technology.
    Dong, J.
    Xiao, M.
    Factors affecting greenhouse microclimate and its regulating techniques: a review2018In: IOP Conference Series: Earth and Environmental Science, 2018, Vol. 167, no 1, article id 012019Conference paper (Refereed)
    Abstract [en]

    This paper reviews factors affecting greenhouse microclimate and its regulating techniques towards upgrading the greenhouse applications in the area of southeast China which have little or very basic technology integration. The microclimate of greenhouse is apparently influenced by the shape and its orientation, the wind direction, the property of covering material, and the use of insect-proof screen as they eventually affect the total solar radiation, the thermal characterises, and the flow pattern inside. The natural ventilation and sun block are the most common method to cool the greenhouse, but more efficient evaporative cooling such as pad-fan system, misting/fogging system and roof sprinkler are required with extreme temperatures. The earth to air heat exchanger and the heat storage using phase change material may be used for heating or cooling throughout the year which are more economic and energy-saving than other traditional thermal technologies. The reviewed knowledge provides insights into upgrading greenhouse applications in Ningbo area towards more sustainable and efficient greenhouse farming.

  • 123. Li, G
    et al.
    Tang, L
    Zhang, Xingxing
    Dalarna University, School of Technology and Business Studies, Energy Technology.
    Hao, J
    Xiao, M
    Dong, J
    Numerical and experimental investigations on improving the efficiency of Clean-In-Place procedures in closed processing systems: A review2017Conference paper (Refereed)
    Abstract [en]

    This paper reviews the recent numerical and experimental investigations on improving the efficiency of Clean-In-Place procedures thus saving operation energy. The paper covers the fouling of equipment surfaces, the concept of CIP and its operation practices, the physical factors controlling the efficiency of CIP procedures with a special attention being paid to the hydrodynamic force of the cleaning fluids. The studies show that CIP efficiency dependents on many factors, such as the type of soil to be removed, the cleaning time, the temperature of cleaning agent, and the favourable hydrodynamic force of the moving liquid. Among the hydrodynamic factors, the wall shear stress and its fluctuation rate reported to be the dominating factor for cleaning straight circular pipes. Whilst for cleaning of more complex geometries and areas difficult to clean, the controlling factor may also include the flow pattern, flow exchange, flow turbulence, and the property of the recirculation zone.

  • 124. Li, Guozhen
    et al.
    Tang, Llewellyn
    Zhang, Xingxing
    Dalarna University, School of Technology and Business Studies, Energy Technology.
    Xiao, Manxuan
    Dong, Jie
    Effect of solar radiation and natural ventilation on temperature distribution in a greenhouse: a numerical study2017Conference paper (Refereed)
  • 125.
    Lidberg, Tina
    Dalarna University, School of Technology and Business Studies, Energy Technology. Högskolan i Gävle, Energisystem.
    Influences from Building Energy Efficiency Refurbishment on a Regional District Heating System2018Licentiate thesis, comprehensive summary (Other academic)
    Abstract [en]

    Improving energy performance of existing buildings is an important part in decreasing energy use and in turn reduce the greenhouse gas emissions caused by human activity and the primary energy use.

    To be able to evaluate how energy refurbishment influences the greenhouse gas emissions and the primary energy use a wider system perspective is needed that puts the building in its context. This thesis deals with energy refurbishment packages performed on multi-family buildings within district heated areas and how they influence greenhouse gas emissions and primary energy use when the district heating use is altered.

    A simulated building is used to evaluate several energy refurbishment packages. The results are used as input data for models of district heating systems to cost optimize the district heating production. The results from the cost optimization are used to evaluate the impact on greenhouse gas emissions and primary energy use.

    The results show a difference between measures that saves district heating without increasing the use of electricity and measures that increases the use of electricity while district heating is saved. For example, a building refurbishment package including only building envelope improvements saves the same amount of district heating as a package including only mechanical ventilation with heat recovery. Despite this, the emissions of greenhouse gases and the use of primary energy is to a greater extent reduced in the first package because the use of electricity remains unchanged.

    Comparing energy refurbishment packages performed on the same building, but within different district heating systems, show the importance of the design of the district heating system. Depending on the fuel types used and to which extent electricity is co-produced in the district heating system, the results of implementing the energy refurbishment packages vary. The largest reduction of greenhouse gases and primary energy use occurs when a refurbishment package is performed on a building in a district heating system with high share of biofuel and no electricity production.

  • 126.
    Lidberg, Tina
    et al.
    Dalarna University, School of Technology and Business Studies, Energy Technology.
    Gustafsson, Marcus
    Dalarna University, School of Technology and Business Studies, Energy Technology. KTH.
    Myhren, Jonn Are
    Dalarna University, School of Technology and Business Studies, Construction.
    Olofsson, Thomas
    Dalarna University, School of Technology and Business Studies, Energy Technology. Umeå universitet.
    Trygg, L.
    Comparing different building energy efficiency refurbishment packages performed within different district heating systems2017In: Energy Procedia, ISSN 1876-6102, E-ISSN 1876-6102, Vol. 105, p. 1719-1724Article in journal (Refereed)
    Abstract [en]

    This study analyses the differences in primary energy (PE) use of a multi-family building refurbished with different refurbishment packages situated in different district heating systems (DHS). Four models of typical DHS are defined to represent the Swedish DH sector. The refurbishment packages are chosen to represent typical, yet innovative ways to improve the energy efficiency of a representative multi-family building in Sweden. The study was made from a broad system perspective, including valuation of changes in electricity use on the margin. The results show a significant difference in PE savings for the different refurbishment packages, depending on both the package itself as well as the type of DHS. Also, the package giving the lowest specific energy use per m2 was not the one which saved the most PE. © 2017 The Authors.

  • 127.
    Lidberg, Tina
    et al.
    Dalarna University, School of Technology and Business Studies, Energy Technology.
    Gustafsson, Marcus
    Dalarna University, School of Technology and Business Studies, Energy Technology. KTH.
    Myhren, Jonn Are
    Dalarna University, School of Technology and Business Studies, Construction.
    Olofsson, Thomas
    Dalarna University, School of Technology and Business Studies, Construction. Umeå universitet.
    Ödlund, L
    Environmental impact of energy refurbishment of buildings within different district heating systems2018In: Applied Energy, ISSN 0306-2619, E-ISSN 1872-9118, Vol. 227, no SI, p. 231-238Article in journal (Refereed)
    Abstract [en]

    The refurbishment of existing buildings is often considered a way to reduce energy use and CO2 emissions in the building stock. This study analyses the primary energy and CO2 impact of refurbishing a multi-family house with different refurbishment packages, given various district heating systems. Four models of typical district heating systems were defined to represent the Swedish district heating sector. The refurbishment packages were chosen to represent typical, yet innovative ways to improve the energy efficiency and indoor climate of a multi-family house. The study was made from a system perspective, including the valuation of changes in electricity use on the margin. The results show a significant difference in primary energy use for the different refurbishment packages, depending on both the package itself as well as the type of district heating system. While the packages with heat pumps had the lowest final energy use per m2 of floor area, air heat recovery proved to reduce primary energy use and emissions of CO2-equivalents more, independent of the type of district heating system, as it leads to a smaller increase in electricity use.

  • 128.
    Lidberg, Tina
    et al.
    Dalarna University, School of Technology and Business Studies, Energy Technology.
    Olofsson, Thomas
    Dalarna University, School of Technology and Business Studies, Construction. Umeå universitet.
    Trygg, Louise
    Linköpings Universitet.
    System impact of energy efficient building refurbishment within a district heated region2016In: Energy, ISSN 0360-5442, E-ISSN 1873-6785, Vol. 106, p. 45-53Article in journal (Refereed)
    Abstract [en]

    The energy efficiency of the European building stock needs to be increased in order to fulfill the climate goals of the European Union. To be able to evaluate the impact of energy efficient refurbishment in matters of greenhouse gas emissions, it is necessary to apply a system perspective where not only the building but also the surrounding energy system is taken into consideration.

    This study examines the impact that energy efficient refurbishment of multi-family buildings has on the district heating and the electricity production. It also investigates the impact on electricity utilization and emissions of greenhouse gases.

    The results from the simulation of four energy efficiency building refurbishment packages were used to evaluate the impact on the district heating system. The packages were chosen to show the difference between refurbishment actions that increase the use of electricity when lowering the heat demand, and actions that lower the heat demand without increasing the electricity use. The energy system cost optimization modeling tool MODEST (Model for Optimization of Dynamic Energy Systems with Time-Dependent Components and Boundary Conditions) was used.

    When comparing two refurbishment packages with the same annual district heating use, this study shows that a package including changes in the building envelope decreases the greenhouse gas emissions more than a package including ventilation measures.

  • 129.
    Lidberg, Tina
    et al.
    Dalarna University, School of Technology and Business Studies, Energy Technology.
    Ramírez Villegas, Ricardo
    Dalarna University, School of Technology and Business Studies, Energy Technology.
    Olofsson, Thomas
    Dalarna University, School of Technology and Business Studies, Energy Technology.
    Eriksson, Ola
    University of Gävle.
    AN APPROACH TO ILLUSTRATE STRATEGIES FOR IMPROVED ENERGY EFFICIENCY AT THE MUNICIPAL LEVEL2014In: Proceedings from the 14th International Symposium on District Heating and Cooling: Proceedings from the14th InternationalSymposium on District Heating and Cooling September, 6-10, 2014 Stockholm, SWEDEN / [ed] Anna Land, Swedish District Heating Association, 2014, p. 50-55Conference paper (Refereed)
  • 130.
    Lindberg, Eva
    et al.
    Dalarna University, School of Technology and Business Studies, Energy Technology.
    Fiedler, Frank
    Dalarna University, School of Technology and Business Studies, Energy Technology.
    Bales, Chris
    Dalarna University, School of Technology and Business Studies, Energy Technology.
    Past and future of European Solar Energy School2007In: Proceedings of ISES Solar World Congress 2007: Solar energy and human settlement, vols I-V, 2007, Vol. 4, p. 3014-3018Conference paper (Refereed)
    Abstract [en]

    The European Solar Engineering School ESES is a one-year master program that started in 1999 at the Solar Energy Research Center SERC, Dalarna University College. It has been growing in popularity over the years, with over 20 students in the current year. Approximately half the students come from Europe, the rest coming from all over the globe. This paper describes the contents and experiences from eight years of running the programme an the adapting the programme to the Bologna process. The majority of the students from ESES have found work in the solar industry, energy industry or taken up PhD positions. An alumni group has been started that actively gives support to past, present and potential future students.

  • 131.
    Linde, Daniel
    Dalarna University, School of Technology and Business Studies, Energy Technology.
    Evaluation of a Flat-Plate Photovoltaic Thermal (PVT) Collector prototype2016Independent thesis Advanced level (degree of Master (Two Years)), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    This Master thesis, in collaboration with Morgonsol Väst AB, was completed as a part of the Solar Energy engineering program at Dalarna University. It analyses the electrical and thermal performance of a prototype PVT collector developed by Morgonsol Väst AB. By following the standards EN 12975 and EN ISO 9806 as guides, the thermal tests of the collector were completed at the facility in Borlänge. The electrical performance of the PVT collector was evaluated by comparing it to a reference PV panel fitted next to it. The result from the tests shows an improved electrical performance of the PVT collector caused by the cooling and a thermal performance described by the linear efficiency curve ηth=0.53-21.6(Tm-Ta/G). The experimental work in this thesis is an initial study of the prototype PVT collector that will supply Morgonsol Väst with important data for future development and research of the product.

  • 132. Liu, G
    et al.
    Xiao, M
    Zhang, Xingxing
    Dalarna University, School of Technology and Business Studies, Energy Technology.
    Gál, Csilla V
    Dalarna University, School of Technology and Business Studies, Energy Technology.
    Chen, X
    Liu, L
    Pan, S
    Wu, J
    Tang, L
    Clements-Croome, D
    A review of air filtration technologies for sustainable and healthy building ventilation2017In: Sustainable cities and society, ISSN 2210-6707, Vol. 32, p. 375-396Article in journal (Refereed)
    Abstract [en]

    Urbanization increased population density in cities and consequently leads to severe indoor air pollution. As a result of these trends, the issue of sustainable and healthy indoor environment has received increasing attention. Various air filtration techniques have been adopted to optimize indoor air quality. Air filtration technique can remove air pollutants and effectively alleviate the deterioration of indoor air quality. This paper presents a comprehensive review on the synergistic effect of different air purification technologies, air filtration theory, materials and standards. It evaluated different air filtration technologies by considering factors such as air quality improvement, filtering performance, energy and economic behaviour, thermal comfort and acoustic impact. Current research development of air filtration technologies along with their advantages, limitations and challenges are discussed. This paper aims to drive the future of air filtration technology research and development in achieving sustainable and healthy building ventilation.

  • 133.
    Lorenz, Erik
    et al.
    Dalarna University, School of Technology and Business Studies, Energy Technology.
    Dahlin, Frida
    Dalarna University, School of Technology and Business Studies, Energy Technology.
    Fossilfri Fjärrvärme: Möjligheter till konvertering av fossila spetslastpannor hos Falu Energi och Vatten2018Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    After the Paris climate agreement, the requirements were raised on the district heating sector in Sweden to eliminate the fossil fuels from the production. This concerns mainly the peak load production during cold season when the fossil boilers are needed the most. To get rid of the peak load production of fossil fuels, it is necessary to find an alternative way of producing the heat that still fulfill the requirements on the boilers. You often need to have a flexible load control and a quick startup of the boiler. It is possible to convert a fossil boiler to be able to use bio oil or bio diesel, more or less keeping the same properties of the boiler. The requirements on the system in such a conversion is dependent on the fuel and its properties. In this study the definition of fossil free district heating refers to only the fuel used for production.

    "Falu Energi och Vatten" (FEV) is a district heating company in a town called Falun in Sweden. They use approximately 3 % fossil fuel (liquefied petroleum gas and heating oil 1) of the energy used for district heat production and have the ambition to be fossil free. The district heating grid in Falun has been studied to examine the economic consequences of a conversion of fossil boiler for peak load production. The technical requirements that leads to economic consequences have also been studied.

    By studying literature and contacting some technology providers, fuel providers and other heat producers the costs that will be affected by the conversion has been obtained. Three different fuel choices in a boiler conversion have been studied; MFA, RME and HVO. To evaluate the economic consequences, a Life cycle cost analysis (LCC) has been used. Apart from the three different choices of fuel, an LCC has also been calculated for a scenario where you keep using fossil fuels. A sensitive analysis has also been made where different energy demands, prices for energy and the cost of capital have been studied.

    The results show that all the different choices of bio fuels studied for a conversion is more expensive than keep on using the fossil fuels for FEV. MFA has the lowest LCC, but the largest investment. The price for HVO and the taxes when used for heating makes it substantially more expensive than the other fuels. The sensitive analysis shows that the price of energy and energy demand in the future is crucial for the economic consequences. These must change substantially if the investments are to be considered profitable during the calculation period of 10 years. MFA has a lower LCC the greater the energy demand is for FEV in the future. RME has a lower LCC the lesser the energy demand is.

    It has emerged that the necessary measures and costs for a conversion of boilers differs a lot depending on local pre-conditions of the boilers and the storage of fuels. The calculations are based on several assumptions making the results uncertain and should be handled with caution.

    The results are also specific to the conditions of FEV which should be considered before the results can be applied under other circumstances.

  • 134.
    Lorenz, Klaus
    Dalarna University, School of Technology and Business Studies, Energy Technology.
    Solvärme i flerbostadshus2014Report (Other academic)
    Abstract [sv]

    I detta arbete har utbyte och kostnader för solvärme kopplat till fjärrvärmeanslutna fastigheter analyserats. Inledande refereras olika kopplingsförslag som Svensk Fjärrvärme rekommenderar. Mätningarna på primärinkopplade solvärmesystem (där systemet levererar till fjärrvärmenätet), som nyligen har sammanställts i ett Fjärrsyn projekt aktualiserar frågeställningen i vilka fall solvärmen bör kopplas in med primär- respektive med sekundärinkoppling. Skillnaden är system med ackumulatortank som minskar inköpt fjärrvärme å ena sidan (sekundärinkoppling) och system som matar solvärmen in i fjärrvärmens primärledning å andra sidan. I både fallen förbättras fastighetens energiprestanda enligt den svenska definitionen, som baseras på inköpt energi.

  • 135. Luo, H.
    et al.
    Liang, X.
    Lu, J.
    Zhang, Xingxing
    Dalarna University, School of Technology and Business Studies, Energy Technology.
    Applicability analysis of insulation in different climate zones of China2017In: Energy Procedia, ISSN 1876-6102, E-ISSN 1876-6102, Vol. 142, p. 1835-1841Article in journal (Refereed)
    Abstract [en]

    In this paper we evaluated the applicability of the widely-used passive design strategy i.e., insulation, in three typical climate zones of China. Software IES VE was used for modelling and simulation of performance of insulation in a residential house. The practical behavior patterns of Chinese family from survey were utilized for analyzing the thermal characteristics of the house. Four parameters of the results were selected for analyzing the performance of insulation in three cities of China. The conditions varying in time periods and locations were compared on the basis of the simulation.

  • 136.
    Luthander, Rasmus
    et al.
    Uppsala universitet, Fasta tillståndets fysik.
    Psimopoulos, Emmanouil
    Dalarna University, School of Technology and Business Studies, Energy Technology. Uppsala universitet, Fasta tillståndets fysik.
    Widén, Joakim
    Uppsala universitet, Fasta tillståndets fysik.
    Demand Side Management Using PV, Heat Pumps and Batteries: Effects on Community and Building Level2017In: Proceedings of the 33rd European Photovoltaic Solar Energy Conference, 2017Conference paper (Refereed)
    Abstract [en]

    This study examines how the energy management optimization on household level affects the maximum power flow in a community of houses and the contribution to load smoothening in the community. A detailed model of a single-family house with exhaust air heat pump and photovoltaic system is used in combination with high-resolution weather, electricity use and hot water use data. All five houses in the community are identical but the occupancy of the residents and their use of electric appliances and hot water differ. Results show no reduction of the maximum power delivered to the grid if the houses are operated to optimize the individual self-consumption and self-sufficiency. The highest aggregated power from the grid for the whole community occurred when the heat pumps were controlled by the PV electricity production but without any battery storage. This case also resulted in least smoothing of the aggregated household loads in the community. The conclusion of the study is that energy optimization for individual households in a community do not have to result in a reduction of the aggregated load and power production.

  • 137.
    Magnusson, Benny
    et al.
    Dalarna University, School of Technology and Business Studies, Energy Technology.
    Ekerind, Mattias
    Dalarna University, School of Technology and Business Studies, Energy Technology.
    FTX-system i flerbostadshus2018Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    The purpose of the report is to investigate potential energy savings when installing FTX systems in multi-family houses. Three common types of heat exchangers are compared to each other: rotary, counter current and cross heat exchangers. The purpose is to see how much the different systems reduce the specific energy use of the building. The house in the study is a typical multi-family house from the 70's located in Borlänge. Exhaust air ventilation is installed, and the building shell is of expected standard of an older apartment block. The specific energy use was calculated at 156 kWh/m

    2 year, far from BBR’s requirements for new construction or major renovations.

    No new measurements have been made on site in the study and the focus lies in processing and evaluating secondary data. Information about the FTX systems was extracted from quotations from selected suppliers. Data regarding the building was derived from blueprints while usage data was collected from the SVEBY project, which compiles surveys and measurements of residents’ habits.

    It was found that the installation of FTX systems, regardless of type, reduced the specific energy consumption by about 30%, down to around 110 kWh / m

    2 year. Only installation of an FTX system would not suffice to meet current BBR requirements. Furthermore, it was found that a theoretical renovation of the building shell according to BBR´s new building regulations had an equivalent result and reduced the building's specific energy consumption by 25%. As a combined measure, the installation of an FTX system and building shell renovation according to BBR´s new building regulations would make it possible to meet BBR’s requirements for specific energy use.

    The negligible difference in performance of the various FTX systems can, to some extent, be explained by the lack of data available for the study. Nevertheless, the choice of FTX system should largely be based on other criteria such as cost of assembly, installation and maintenance as well as comfort in terms of noise level and filtered air pollution.

  • 138. Malmqvist, C.
    et al.
    Wallin, Elisabeth
    Dalarna University, School of Technology and Business Studies, Energy Technology.
    Lindström, Anders
    Dalarna University, School of Technology and Business Studies, Forest and Wood Technology.
    Säll, H.
    Differences in bud burst timing and bud freezing tolerance among interior and coastal seed sources of Douglas fir2017In: Trees, ISSN 0931-1890, E-ISSN 1432-2285, Vol. 31, no 6, p. 1987-1998Article in journal (Refereed)
    Abstract [en]

    The need for species that will grow well through ongoing climate change has increased the interest in Douglas fir [Pseudotsuga menziesii (Mirb.) Franco] in Sweden. One of the most common problems seen in plantations of Douglas fir seedlings is damage caused by late spring frost, known to be highly correlated with the timing of bud burst. The objective of this study was to investigate spring-related bud development under Nordic conditions of seven Douglas fir provenances and to compare data with a local provenance of Norway spruce (Picea abies (L.) Karst). Results from a field trial and a greenhouse-based study were compared. The interior Douglas fir provenances exhibited an earlier bud burst than coastal provenances, both in the greenhouse and in the field trial. When comparing differences within the groups of interior and coastal Douglas fir provenances, no differences could be found. The local Norway spruce, only grown in the greenhouse, showed an intermediate bud development profile similar to the interior Douglas fir provenance Three Valley. We therefore suggest that Three Valley could be planted at the same locations as the investigated local provenance of Norway spruce in mid-Sweden. To avoid spring frost damage the Douglas fir seedlings need to be frozen stored and planted late in spring. Planting under shelterwood can also help protect the seedlings from spring frost damages. As similar results for bud development patterns of Douglas fir and Norway spruce provenances were obtained from the greenhouse and field trials, greenhouse tests could facilitate selection of provenances.

  • 139.
    Mattsson, Anders
    et al.
    Dalarna University, School of Technology and Business Studies, Forest and Wood Technology.
    Hernandez Velasco, Marco
    Dalarna University, School of Technology and Business Studies, Energy Technology.
    Rusu, Cristina
    Acreo Swedish ICT AB.
    Pietrzak, Malgorzata
    Azorina S.A.
    Ferreira, Raquel
    Azorina S.A.
    Radoglou, Kalliopi
    Democritus University of Thrace.
    Smirnakou, Sonia
    Democritus University of Thrace.
    Bantis, Filippos
    Democritus University of Thrace.
    Fulgaro, Nicoletta
    Università degli Studi dell'Insubria.
    Kotilainen, Titta
    Valoya OY.
    ZEPHYR Project – Deliverable D7.6: Articles and peer-reviewed papers2015Report (Other (popular science, discussion, etc.))
  • 140.
    Mazraeh, Hifa
    et al.
    Dalarna University, School of Technology and Business Studies, Energy Technology.
    Abdullahi, Abdiaziz
    Dalarna University, School of Technology and Business Studies, Energy Technology.
    Värmeåtervinning ur spillvatten för flerbostadshus: Kornstigen 25 i Borlänge2018Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    The purpose of this work is to compile knowledge of waste water recovery systems in multi-family houses from literature, previous studies and relevant actors on the subject area. The purpose is also to make temperature measurements in a multi-family house in Borlänge to calculate and analyze the energy saving potential of the Ekoflow heat exchanger from Isaksson Rostfria AB.

    Ekoflow is a waste water heat exchanger that recycles heat energy from wastewater. Through wastewater heat exchanger, the waste water flows from the drain and the cold water in the countercurrent direction. Ekoflow has been installed in some bath houses and hotels and showed good recovery rates in these areas.

    It is a little difficult to find a temperature meter on the market that can measure and store the measured values of a vertical drainage stream. Therefore, produced own temperature meter, which was used to collect measurement data for analysis and calculation of the results.

    Application of the technology in the reference building adds some problems. One problem is that both gray and black water pass through the same pipe which reduces the temperature of the waste water. The second problem is that the building does not have a common connection point to the municipal sewers, which means that a heat exchanger will be needed for each main line.

    Energy consumption in multi-family houses varies depending on the living space and number of residents in the house. The number of residents in the reference building is not known but the temperature and water flow and spill water temperature measurements showed that the building has high hot water consumption. Energy saving depends on several parameters such as incoming cold and waste water temperature to waste water heat exchanger and the length of heat exchanger. The energy savings for three different lengths of the Ekoflow heat exchanger were calculated and a 48-meter heat exchanger showed energy savings of approximately 40 MWh / year, which is profitable from the energy saving perspective.

  • 141.
    Menthon, Maxence
    et al.
    Dalarna University, School of Technology and Business Studies, Energy Technology.
    Van Migom, Léa
    Dalarna University, School of Technology and Business Studies, Energy Technology.
    Reducing energy consumption of refrigerators byusing the outside temperature2018Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Nowadays, many electrical appliances are used daily. The refrigerator is one of them.

    Consequently, by affecting the energy used by the refrigerator, a huge amount of energy,

    greenhouse gases (GHG) emissions and money can be saved. It is what this thesis tries to do

    by applying a concept: using the cold from outside. Indeed, this report exposes the process to

    answer the following question:

    How much energy, GHG emissions and money can be saved by using the cold from

    outside on the refrigerating appliances?

    To do so, measurements have been done on a refrigerator placed in a climate chamber. The

    experiment procedure is inspired by the Swedish standard of energy consumption testing in

    order to have the most relevant results as possible. The results of the measures were then used

    to create a mathematical modelling. And finally, by applying the modelling at different

    climate of the world represented by chosen cities, calculations were made to estimate the

    energy, GHG emissions and money savings which can be done thanks to this concept.

  • 142.
    Molin, Elin
    et al.
    Dalarna University, School of Technology and Business Studies, Energy Technology.
    Stridh, B.
    Molin, A.
    Wäckelgård, Ewa
    Dalarna University, School of Technology and Business Studies, Energy Technology.
    Experimental yield study of bifacial PV modules in Nordic conditions2018In: IEEE Journal of Photovoltaics, ISSN 2156-3381, E-ISSN 2156-3403, Vol. 8, no 6, p. 1457-1463Article in journal (Refereed)
    Abstract [en]

    This study reports on the first full-year field study in Sweden using bifacial photovoltaic modules. The two test sites are located on flat roofs with a low albedo of 0.05 in Linköping (58 °N) and were studied from December 2016 to November 2017. Site 1 has monofacial and bifacial modules with a 40° tilt facing south, which is optimal for annual energy yield for monofacial modules at this location. Site 2 has monofacial 40° tilt south-facing modules and bifacial vertical east–west orientated modules. The annual bifacial energy gain (BG E ) was 5% at site 1 and 1% at site 2 for albedo 0.05. The difference in power temperature coefficients between bifacial and monofacial modules was estimated to influence BG E by +0.4 and +0.1 percentage points on site 1 and 2, respectively. A higher albedo could be investigated on a sunny day with fresh snow for the bifacial east–west modules. The specific yield was 7.57 kWh/kW p , which was a yield increase of 48% compared with tar paper at similar solar conditions.

  • 143.
    Morales-Pallares, Marcos
    Dalarna University, School of Technology and Business Studies, Energy Technology.
    Long Term Sustainability of Standalone PV Systems for Community Services: Case Studies from Rwanda2016Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    This thesis was developed with a twofold aim in mind. In first place, to study some of the components that are required to achieve long term sustainability of standalone PV systems for community services. This means, to put in place the necessary ingredients to ensure that standalone PV systems that power schools, health centers or administration offices, among other public institutions, are able to last for their typical life time (20-25 years).

    In particular, the focus of this theoretical part of the thesis is mainly set on both the technical and socio-technical dimensions of long term sustainability. As part of the first one, the study delves into aspects related to PV system design and quality in installations, sustainable system use and operation, as well as maintenance theory. As part of the socio-technical dimension, research in the literature has been done mainly about those social concepts related to the community surrounding a PV system, aspects related to system operation from a user’s perspective, as well as maintenance seen from a socio-technical point of view. Complementarily to the previous two, other dimensions such as the financial, governmental, environmental and related to project management are also introduced.

    The second part of this thesis is based on work done during a one month trip to Rwanda. During this time three main case studies were developed around two schools and one health center, in order to assess the degree of fulfilment of the different dimensions of long-term sustainability in these sites, setting most of the efforts on both the technical and the socio-technical dimensions. Additionally, three complementary (and shorter) visits to two administration offices and an additional school also took place. These visits plus some interviews to several Rwandan companies completed the picture of long-term sustainability of standalone PV systems in the Rwandan context.

    Although the components and the installation of standalone PV systems in recent national Rwandan programs were of high quality, there was generally a lack of adequate direct and indirect lightning protections, in spite of the fact that Rwanda is one of the places with highest keraunic levels in the world. In some cases, previous systems had poor designs, used low quality wiring or installed low quality batteries, not in compliance with international standards. In terms of maintenance and component replacements, these elements were almost never taken into account as part of any original project plan, including financial and human resources. However, although maintenance structures only started to be defined in national programs after system installation, they all lacked the actors and instruments to properly trace quality in maintenance.

    In socio-technical terms, efforts to engage or transfer system operation and energy efficiency knowledge, in the form of trainings for end-users, did not seem to be sufficient. Therefore, some sites experimented a notable load increase or a load shift. In most situations, energy consumption could be optimized, either by using energy efficient appliances (e.g. namely thin clients, energy efficient fridges) or by optimizing the frequency and total time of their use (i.e. autoclaves in health centers). Simple but yet effective operation strategies could also be easily adopted in order to adequate energy use to energy generation, as per the examples included in this thesis. Last but not least, remote monitoring solutions should be considered in the future as means to improve operation and maintenance, especially in wide national projects.

  • 144.
    Moretti, Sebastián
    et al.
    Dalarna University, School of Technology and Business Studies, Energy Technology.
    Simwinga, Abiya
    Dalarna University, School of Technology and Business Studies, Energy Technology.
    Economic and Technical Analysis of Integration of PV into the Existing Diesel Power Station in Shang’ombo, Zambia2017Independent thesis Advanced level (degree of Master (Two Years)), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    The main objective of this study was to carry out an economical and technical analysis of integrating PV into an existing 320 kW diesel power plant in Shang’ombo township in the western province of Zambia. Additionally, the study evaluates the best feasible solution by analyzing different hybrid combinations and configurations whilst taking into account the least Levelized Cost of Electricity (LCOE) and the Net Present Cost (NPC) with regard to the Life Cycle Cost of the project. Hybrid Optimization of Multiple Electric Renewables- (HOMER) software was used for modelling and simulation of five different off-grid solutions. CASE A was for the current system (100 % diesel generated power plant), CASE B: current system and PV, CASE C: Current system, PV and battery, CASE D: Current system, PV, battery and an additional small generator and CASE E: 100% PV and battery.

    The results show that the current system (100 % diesel generator system) is not economically sustainable as it has a very high LCOE of $0.50/kWh due to high cost of diesel and high costs of operation and maintenance of diesel generator sets. On the other hand, a system with 100 % PV with batteries gave the lowest LCOE of $ 0.31/kWh, as it had the lowest operation and maintenance costs and, additionally, zero carbon emissions. Overall, the NPC of the system with 100 % PV with batteries was 1.7 times lower than the current diesel system. However, if the utility company, Zambia Electricity Supply Corporation (ZESCO), would prefer to use the existing diesel generators for the PV/Diesel hybrid system, then CASE C would be the best solution. This hybrid configuration achieves 87 % solar fraction with LCOE of $ 0.39/kWh.

    Lastly, the results generally showed that the initial capital cost of solar energy projects was relatively higher as compared to the equivalent diesel based plants. However, with the continued down ward trend in the price of PV per kWp, solar is the best solution to bridge the current energy deficit that Zambia is currently facing. Additionally, solar solutions answers the worlds cry for clean energy which is environmentally friendly and reduces on the impacts of global warming.

  • 145.
    Mugisha, Jean Claude
    Dalarna University, School of Technology and Business Studies, Energy Technology.
    A study on Auxiliary Battery Energy Storage to Mitigate PV Output Power Fluctuations: Case Study: 8.5 MW Agahozo Shalom Youth Village (ASYV) PV Power Plant in Rwanda2018Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Solar energy is experiencing a rapid growth worldwide and it is a promising technology to play a vital role in future power systems. However, the natural intermittent of solar energy resources affect the quality of the output power from a solar system putting its dispatchability in question. Battery Energy Storage System (BESS) is among the solutions to suppress PV power fluctuations and allow smooth PV power production as result. In this work, BESS was modelled, integrated and simulated for Agahozo Shalom Youth Village (ASYV) PV Power Plant located in Rwanda. MATLAB/Simulink was used as modelling and simulation tool and Excel was used in data analysis. For ease of work, one of eight PV arrays at the power plant was considered and the results were scaled up to the entire power plant afterwards.

    Annual data for year 2017 was analysed and the worst-case scenario which is the day with highest irradiance variation was found. Both PV power and ambient temperature data for this day were used as input to the model. Four smoothing approaches namely Low Pass Filter (LPF), Simple Moving Average (SMA), Exponential Moving Average (EMA) and Ramp Rate Control (RRC) were investigated in detail, applied to the model and compared in terms of performance and battery size that each approach would require. The degree to which power output needs to be smoothed can vary based on regulatory requirements and the technical conditions of the power grid. For this reason, three Ramp Rate Limits (RRLs) namely ±10 %, ±20 % and ±30 % of the rated PV array power per minute were applied in smoothing algorithms to see how large the battery storage would be if Rwandan grid operator was to impose one of the aforesaid RRLs.

    The results showed that all smoothing methods managed to smoothen out PV array power at all RRLs as intended. The difference occurred in performance of smoothing methods and battery size in terms of power and energy that each method required. In all cases, it was noticed that both LPF and EMA displayed almost similar results which made it difficult to make a clear distinction between the two. However, in their slight difference, EMA required a slightly smaller battery size. The memory effect of SMA was noticed and this method was requiring bigger battery size at all RRLs. The RRC performance was better especially at ±10 % RRL compared to other three methods. The particularity of RRC was that it only allows the battery to respond when needed and the battery charges or discharges the exact amount of power needed. This was different from the other three smoothing methods. They were always allowing the battery to respond even when the present power ramp is within the set RRL resulting in high charging/discharging cycles which causes cyclic degradation of the battery. In addition, these methods over-smoothed the PV array power where more than needed power could be absorbed or delivered by the battery resulting in unnecessary bigger battery size.

    Some of downsides of RRC method were that it requires bigger battery size in terms of energy and it could be more sensitive to the uncertainty associated with PV array power measurement compared to other methods. Nonetheless, its battery size in terms of power requirement was less than other methods since it does not over-smooth the PV array power. Since RRC and EMA methods were requiring less battery power and less battery energy at all RRLs respectively, both methods were chosen while scaling up the results to the entire power plant. Using EMA smoothing methods over RRC at ±10 % RRL could results in saving $113 thousand of battery capital cost. However, at ±20 % and ±30 % RRL, the RRC method was found to be the best option since it needs less capital cost than EMA smoothing approach.

  • 146.
    Myhren, Jonn Are
    et al.
    Dalarna University, School of Technology and Business Studies, Construction.
    Heier, Johan
    Dalarna University, School of Technology and Business Studies, Energy Technology.
    Hugosson, Mårten
    Dalarna University, School of Technology and Business Studies, Business Administration and Management.
    Zhang, Xingxing
    Dalarna University, School of Technology and Business Studies, Energy Technology.
    The perception of Swedish housing owner’s on the strategies to increase the rate of energy efficient refurbishment of multi-family buildings2018In: Intelligent Buildings International, ISSN 1750-8975, E-ISSN 1756-6932Article in journal (Refereed)
    Abstract [en]

    Improving the energy performance of existing buildings is crucial for reaching both EU and national climate and energy targets. The main objective of this study was to map challenges that Swedish housing owners perceive when making energy-efficiency refurbishments. A secondary objective was to compare how well these challenges relate to national strategies. The study applied a combined methods approach with audience response meters and in-depth qualitative semi-structured interviews. The housing owners express the view that they have sufficient knowledge of national ambitions to improve the energy performance of buildings and welcome the new building regulations. Despite this supposed knowledge and the current economic situation with beneficial loans, the refurbishment rate still remains low. The housing owners explain that they are concerned about the ‘performance gap’ and request more accurate energy performance predictions. They are also waiting for proof that all sustainability goals can be reached in reality. Probably, too few projects fulfilling ambitions in all categories: economically, socially and energy-wise have been followed up and demonstrated nationally. The new national information centre on refurbishment of buildings may help to spread information about such projects, raise awareness and thus increase the refurbishment rate.

  • 147.
    Myhren, Jonn Are
    et al.
    Dalarna University, School of Technology and Business Studies, Construction.
    Olofsson, Thomas
    Dalarna University, School of Technology and Business Studies, Construction.
    Bergdahl, Martin
    Dalarna University, School of Technology and Business Studies, Energy Technology.
    Lågtemperaturuppvärmning med tilluftsradiatorer och värmeåtervinning i frånluft: en varsam renovering av flerbostadshus för energieffektivisering2014Report (Other academic)
    Abstract [sv]

    För att nå reella sänkningar av energianvändningen i hela byggnadsbeståndet krävs tillgång till kostnadseffektiva renoveringspaket med energieffektiva systemlösningar där samspel mellan installationssystem och byggnad beaktas.

    Denna förstudie belyser möjligheter med alternativa renoveringspaket med lågtemperatur-tilluftsradiatorer och värmeåtervinning i frånluften (FX). Systemkombinationer och jämförelser har gjorts med mera etablerade lösningar med traditionella radiatorer, balanserad mekanisk ventilation (FTX) och solvärme. Mindre prövade lösningar såsom frånluftsmoduler (VBX) kopplat till befintliga värmepumpar och behovsstyrd ventilation undersöktes också.

    Energianvändning och kostnadseffektivitet med de undersökta åtgärdspaketen prövades för två äldre bostadshus med vardera specifika restriktioner: den ena inom fjärrvärmenätet och det andra ett K-märkt hus utanför fjärrvärmenätet. Samtidigt reflekterades det över vilka tekniska lösningar som samtidigt är gynnsammast ur hållbarhetssynpunkt. För flertalet befintliga byggnader behöver såväl metoder som komponenter utvecklas på ett varsamt sätt som uppfyller båda ägarens krav som övergripande mål baserat på systemförutsättning och kostnadseffektivitet.

    Förstudien visar att:

     lågtemperatur-tilluftsradiatorer är en systemkomponent som möjliggör ökad komfort via förvärmning och filtrering av inkommande ventilationsluft, effektivare värmeproduktion och minskning av värmeförluster i distribution av varmvatten. Renovering med installation av FX-system i kombination med lågtemperatur-tilluftradiatorer är ett alternativ till FTX system som begränsar byggåtgärderna i byggnaden och ger lägre livscykelkostnad

     Byggnadsskalets täthet blir avgörande för energinyttan båda med FX- och FTX-system. Förstudien visar att FX-system är fördelaktig i byggnader med dålig lufttäthet

     I byggnader med befintligt frånluftssystem kan behovsstyrning av ventilationen vara ett enkelt och kostnadseffektivt sätt att sänka ventilationsförlusterna och spara energi som alternativ till att installera återvinningssystem

    Förstudien visar klart att energieffektiv renovering kan åstadkommas med val av varsamma metoder som också åstadkommer ökad komfort och systemnytta, utanför såväl som inom fjärrvärmenätet. Samtidigt kan ägarens krav på kostandsnytta nås och byggnaders bevarandekrav uppfyllas.

    Nu krävs det demonstrationsprojekt för att inte minst sprida kunskap i branschen men också applicering på större bostadsområden.

  • 148.
    Niklasson, Fredrik
    et al.
    SP Energiteknik, Borås.
    Persson, Tomas
    Dalarna University, School of Technology and Business Studies, Energy Technology.
    Marknadspotential för bio- och solvärmesystem2008Report (Other academic)
    Abstract [sv]

    I denna rapport analyseras marknaden för kombinerade sol- och pelletsystem, medfokus på småhus. Syftet är att presentera antalet objekt inom olika kategorier av husoch värmesystem som kan vara intressanta för konvertering till bio-sol system samtatt ge en uppskattning av årliga uppvärmningsbehov inom respektive kategori.

    Energistatistik från Statistiska centralbyrån (SCB) har använts i kombination medtidigare studier av byggnadsbestånd och byggnadsutformning. Dessutom harinformation inhämtats från olika branschorganisationer.

    Från föreliggande genomgång står det klart att den största potentialen för bio-solsystem finns på villamarknaden både för helt nya system och för kompletteringar tillbefintliga system. År 2006 fanns det 775 000 småhus med vattenburen värme varav ca183 000 hade vattenburen el. Uppskattningsvis fanns 109 000 småhus med bådevattenburen el och lokaleldstad för biobränsle och ca 118 000 hus bedöms ha haftmöjlighet till oljeeldning (denna grupp har troligtvis minskat ytterligare efter 2006).Bland de elvärmda husen finns också ca 102 000 småhus med frånluftvärmepumpareller luft/vattenvärmepumpar. 365 000 av husen hade en biobränslepanna. Därtillkommer 504 000 hus med direktelvärme, varav ca 292 000 med lokaleldstad.

    Medelförbrukningen för uppvärmning och varmvatten för hus som enbart värms medolja är ca 27 MWh/år, medan motsvarande värde för småhus med vattenburen el är ca15 MWh/år. Småhusen med direktel använder ca 12 MWh/år för uppvärmning ochvarmvatten. Det betyder att ekonomin blir betydligt sämre vid konvertering avelvärmda hus jämfört med oljekonvertering, eftersom energibehovet är lägre samt attinstallationskostnaden kan vara högre.

    En uppskattning av antalet komponenter som inom 10 år kan komma att installeras idessa hus är 213 000 solfångare, 108 000 ackumulatortankar, 106 000 skorstenar,84 000 luftburna pelletkaminer och varmvattenberedare, 40 000 vattenmantladekaminer och 28 000 pannrumspannor. Dessutom tillkommer en utbytesmarknad,kanske speciellt bland husen med biobränslepanna, där gamla pannor byts ut elleräldre människor som tidigare orkat elda med ved till slut byter till pelleteldning.

    Av nybyggda villor uppvärms ca 30 % med el i kombination med biobränsle(troligtvis lokaleldstad) och ungefär lika stor andel värms med enbart vattenburen el(antagligen ofta kompletterat med frånluftvärmepump). Det borde vara av intresse attredan vid nybyggnationen få in integrerade solfångare och pelleteldning i störreutsträckning i nya hus och det kan bli lättare efter att byggreglerna ändras den 1:ajanuari 2010 med en skärpning av kraven för nybyggda hus som använder el föruppvärmning, alltså även el till värmepumpar.

    Potentialen för bio-solsystem till flerbostadshus och lokaler är begränsad då 86 % avflerbostadshusen och nära 70 % av lokalerna värms med fjärrvärme. Det fanns år2006 ca 6200 lokaler med oljeeldning, 4600 lokaler med vattenburen elvärme och5700 lokaler med direktverkande elvärme. I lokalerna som redovisas av SCB ingårinte tillverkande industri. För lägenheter i flerbostadshus gäller att ca 42 000lägenheter värms med enbart olja, 44 000 lägenheter med olja och värmepump,48 000 lägenheter använder direktel och 31 000 lägenheter vattenburen el.

  • 149.
    Niklasson, Fredrik
    et al.
    SP Energiteknik, Borås.
    Persson, Tomas
    Dalarna University, School of Technology and Business Studies, Energy Technology.
    Marknadspotential för sol- och biovärmesystem2010Report (Other academic)
    Abstract [sv]

    I denna rapport analyseras marknaden för kombinerade sol- och pelletsystem, med fokus påsmåhus. Syftet är att presentera antalet objekt inom olika kategorier av hus och värmesystemsom kan vara intressanta för konvertering till bio-sol system samt att ge en uppskattning avårliga uppvärmningsbehov inom respektive kategori.

    Energistatistik från Statistiska centralbyrån (SCB) har använts i kombination med tidigarestudier av byggnadsbestånd och byggnadsutformning. Dessutom har information inhämtatsfrån olika branschorganisationer.

    Från föreliggande genomgång står det klart att den största potentialen för bio-sol systemfinns på villamarknaden både för helt nya system och för kompletteringar till befintliga system.År 2006 fanns det 775 000 småhus med vattenburen värme varav ca 183 000 hade vattenburenel. Uppskattningsvis fanns 109 000 småhus med både vattenburen el och lokaleldstadför biobränsle och ca 118 000 hus bedöms ha haft möjlighet till oljeeldning (dennagrupp har troligtvis minskat ytterligare efter 2006). Bland de elvärmda husen finns också ca102 000 småhus med frånluftvärmepumpar eller luft/vattenvärmepumpar. 365 000 av husenhade en biobränslepanna. Därtill kommer 504 000 hus med direktelvärme, varav ca 292 000med lokaleldstad.

    Medelförbrukningen för uppvärmning och varmvatten för hus som enbart värms med olja ärca 27 MWh/år, medan motsvarande värde för småhus med vattenburen el är ca 15 MWh/år.Småhusen med direktel använder ca 12 MWh/år för uppvärmning och varmvatten. Det betyderatt ekonomin blir betydligt sämre vid konvertering av elvärmda hus jämfört med oljekonvertering,eftersom energibehovet är lägre samt att installationskostnaden kan vara högre.En uppskattning av antalet komponenter som inom 10 år kan komma att installeras i dessahus är 213 000 solfångare, 108 000 ackumulatortankar, 106 000 skorstenar, 84 000 luftburnapelletkaminer och varmvattenberedare, 40 000 vattenmantlade kaminer och 28 000 pannrumspannor.Dessutom tillkommer en utbytesmarknad, kanske speciellt bland husen medbiobränslepanna, där gamla pannor byts ut eller äldre människor som tidigare orkat elda medved till slut byter till pelleteldning.

    Av nybyggda villor uppvärms ca 30 % med el i kombination med biobränsle (troligtvis lokaleldstad)och ungefär lika stor andel värms med enbart vattenburen el (antagligen oftakompletterat med frånluftvärmepump). Det borde vara av intresse att redan vid nybyggnationenfå in integrerade solfångare och pelleteldning i större utsträckning i nya hus och det kanbli lättare efter att byggreglerna ändras den 1:a januari 2010 med en skärpning av kraven förnybyggda hus som använder el för uppvärmning, alltså även el till värmepumpar.

    Potentialen för bio-solsystem till flerbostadshus och lokaler är begränsad då 86 % av flerbostadshusenoch nära 70 % av lokalerna värms med fjärrvärme. Det fanns år 2006 ca 6200lokaler med oljeeldning, 4600 lokaler med vattenburen elvärme och 5700 lokaler med direktverkandeelvärme. I lokalerna som redovisas av SCB ingår inte tillverkande industri. Förlägenheter i flerbostadshus gäller att ca 42 000 lägenheter värms med enbart olja, 44 000lägenheter med olja och värmepump, 48 000 lägenheter använder direktel och 31 000 lägenhetervattenburen el.

  • 150.
    Nouvel, Romain
    et al.
    ZAFH.
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    Manens.
    Bales, Chris
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    Birchal, Sarah
    Fedrizzi, Roberto
    D4.2 Assessed Standardised Energy Generation and Energy Distribution Packages2016Report (Other academic)
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