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  • 1.
    Johansson, Tim
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Construction Engineering.
    Vesterlund, Mattias
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Energy Science.
    Olofsson, Thomas
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Construction Engineering.
    Dahl, Jan
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Energy Science.
    Energy performance certificates and 3-dimensional city models as a means to reach national targets: A case study of the city of Kiruna2016In: Energy Conversion and Management, ISSN 0196-8904, E-ISSN 1879-2227, Vol. 116, p. 42-57Article in journal (Refereed)
    Abstract [en]

    Enhanced dissemination of information regarding energy saving and climate change targeted toward property owners is considered to be an important strategy in order to reach the Swedish national target of energy efficiency in the building sector by 2050. Here the municipality energy advisors and the national register for energy performance certificates can facilitate the mitigation of energy use in the building stock. So far few studies have focused on the practical road map to the national target of energy use on the city/district level and to the communication aspects with stakeholders in the creation of energy city models.In this paper a city energy model is developed based on the requests and need for visualization from a group of energy advisors. Six different scenarios are studied in order to analyze the possibility of reaching the energy targets specified by the government in the town of Kiruna. The results show that: (1) it is possible to automatically create city energy models using extract, transform and load tools based on spatial and non-spatial data from national registers and databases; (2) city energy models improve the understanding of energy use in buildings and can therefore be a valuable tool for energy advisors, real estate companies and urban planners. The case study of Kiruna showed that the proposed energy saving measures in the energy performance certificates need to be implemented and new buildings in the urban transformation must be of high energy standard in order to reach the national target in Kiruna.

  • 2.
    Pericault, Youen
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Architecture and Water.
    Hedström, Annelie
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Architecture and Water.
    Dahl, Jan
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Energy Science.
    Vesterlund, Mattias
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Energy Science.
    Olsson, Göran
    Elgocell AB.
    District heat tracing of water and sewer lines in Kiruna, Sweden2016Conference paper (Other academic)
  • 3.
    Pericault, Youen
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Architecture and Water.
    Risberg, Mikael
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Energy Science.
    Vesterlund, Mattias
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Energy Science.
    Hedström, Annelie
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Architecture and Water.
    Viklander, Maria
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Architecture and Water.
    A novel freeze protection strategy for shallow buried sewer pipes: temperature modelling and field investigation2016In: Proceedings of the 8th International Conference on Sewer Processes & Networks, 2016Conference paper (Other academic)
    Abstract [en]

    The burial of sewer and water pipes below the maximum ground frost depth can be very costly and laborious in regions with cold winters. If a freeze protection measure is applied, the utility lines can be installed in a shallower trench to reduce the excavation needs during construction and maintenance works. One freeze protection measure, so called heat tracing, consist in supplying heat along the pipes. In this work, the use of 4th generation district heating as a heat tracing solution was investigated at a pilot site in Kiruna, Sweden. The influence of the system on sewer and water pipes temperatures was studied experimentally and numerically at a snow-free and snow-covered cross section. The study showed that, under the climatic conditions of the experiment, a heat tracing temperature of 25 ˚C allowed to prevent freezing of the pipes while keeping drinking water pipes in safe temperature range at both cross sections. The other main result was that a finite volume model of the sections was developed and showed a good fitting to the experimental data.

  • 4.
    Pericault, Youen
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Architecture and Water.
    Risberg, Mikael
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Energy Science.
    Vesterlund, Mattias
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Energy Science.
    Viklander, Maria
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Architecture and Water.
    Hedström, Annelie
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Architecture and Water.
    A novel freeze protection strategy for shallow buried sewer pipes: temperature modelling and field investigation2017In: Water Science and Technology, ISSN 0273-1223, E-ISSN 1996-9732, Vol. 76, no 2, p. 294-301Article in journal (Refereed)
    Abstract [en]

    The burial of sewer and water pipes below the maximum ground frost depth can be very costly and laborious in regions with cold winters. If a freeze protection measure is applied, the utility lines can be installed in a shallower trench to reduce the excavation needs. One freeze protection measure, so called heat tracing, consists in supplying heat along the pipes. In this work, the use of 4th generation district heating as a heat tracing solution was investigated at a pilot site in Kiruna, Sweden. The influence of the system on sewer and water pipe temperatures was studied at a snow-free and snow-covered cross section. To this end, five heat tracing temperatures were tested and the corresponding sewer and water pipe temperatures were measured. The field experiment was also simulated with a two dimensional finite volume model. The study showed that, under the climatic conditions of the experiment, a heat tracing temperature of 25 °C allowed to prevent freezing of the pipes while keeping drinking water pipes in a safe temperature range at both cross sections. The other main result was that the developed finite volume model of the sections showed a good fitting to the experimental data

  • 5.
    Risberg, Daniel
    et al.
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Energy Science.
    Vesterlund, Mattias
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Energy Science.
    Risberg, Mikael
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Energy Science.
    Hedström, Annelie
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Architecture and Water.
    Dahl, Jan
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Energy Science.
    Westerlund, Lars
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Energy Science.
    Hållbara, integrerade energi- och VA-system2014Report (Other academic)
  • 6.
    Risberg, Daniel
    et al.
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Energy Science.
    Vesterlund, Mattias
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Energy Science.
    Westerlund, Lars
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Energy Science.
    Dahl, Jan
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Energy Science.
    CFD simulation and evaluation of different heating systems installed in low energy building located in sub-arctic climate2015In: Building and Environment, ISSN 0360-1323, E-ISSN 1873-684X, Vol. 89, p. 160-169Article in journal (Refereed)
    Abstract [en]

    Computational Fluid Dynamics (CFD) simulations were used to study the indoor climate in a low energy building in northern Sweden. The building’s low heat requirement raise the prospect of using a relatively simple and inexpensive heating system to maintain an acceptable indoor environment, even in the face of extremely low outdoor temperature. To explore the viability of this approach, the indoor climate in the building was studied considering three different heating systems: a floor heating system, air heating through the ventilation system and an air heat pump installation with one fan coil unit. The floor heating system provided the most uniform operative temperature distribution and was the only heating system that fully satisfied the recommendations to achieve tolerable indoor climate set by the Swedish authorities. On the contrary, air heating and the air heat pump created a relatively uneven distribution of air velocities and temperatures, and none of them fulfills the specified recommendations. From the economic point of view, the air heat pump system was cheaper to be installed but produced a less pleasant indoor environment than the other investigated heating systems.

  • 7.
    Risberg, Daniel
    et al.
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Energy Science.
    Vesterlund, Mattias
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Energy Science.
    Westerlund, Lars
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Energy Science.
    Dahl, Jan
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Energy Science.
    CFD simulations of the indoor climate of a low energy building in a sub-Arctic climate: an evaluation of different heating systems2013Conference paper (Refereed)
    Abstract [en]

    Computational Fluid Dynamics (CFD) simulations were used to study the indoor climate in a low energy building in northern Sweden. The building’s low heat requirements raise the prospect of using relatively simple and inexpensive heating systems to maintain an acceptable indoor environment, even in the face of extremely low outdoor temperatures. To explore the viability of this approach, the indoor temperature and air velocity distribution inside the building were studied assuming that it was fitted with one of four different heating systems: radiators, an underfloor heating system, a pellet stove, and an air/air heat pump. The radiators produced a relatively uniform horizontal temperature distribution throughout the house. The underfloor system provided an even more uniform temperature distribution. In contrast, the heat pump created a relatively uneven internal temperature distribution. Several locations for the pump were considered, all of which had significant drawbacks. The pellet stove produced a more even temperature distribution than the pump but not to the same extent as the underfloor system or the radiators. Overall, point source heating systems cost less to fit and operate over a given period of time but produce a less clement indoor environment than distributed heating systems.

  • 8.
    Vesterlund, Mattias
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Energy Science.
    District heating system analysis and challenges within the urban transformation of Kiruna2017Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    There is currently an ongoing urban transformation in a small Swedish town named Kiruna, it is located in the very north of Sweden well above the Arctic Circle in a sub-arctic climate. Large part of the town will be relocated due to the ground deformation that is caused by the progressing iron ore mining activity and it is affecting all infrastructures of the town. This thesis aims to accomplish a holistic analysis on the district heating (DH) system for the town of Kiruna and its future challenges.

    Energy companies with a DH system recognize the importance in having a good understanding about the network characteristics, for obtaining an efficient and stabile heat delivery to the end-users. In this thesis, a method for modeling and simulation of meshed DH networks is described, that makes it possible to study and analyze the flow pattern in order to locate non-obvious paths, bottlenecks and overloaded pipes.

    For carrying out the DH simulations a fundamental input is to set the thermal losses for each pipe segment in the model, a fictitious series with all pipe diameters is created which corresponds to the annual losses in the real network. In comparison with the pipes series manufactured today the created one is best described by the series with least insulation and highest thermal losses. The studied network has its origin in the 60th and is the sum of the different piping technics that has been valid over time, this mixture is positioning the thermal performance as a close to a worst-case scenario.

    To the meshed DH network a number of heat production sites are connected for delivering the thermal requested by the end-users, each site consisting of several boilers and using different resources. A hybrid evolutionary-Mixed Integer Linear Programing (MILP) optimization approach is developed and applied for finding the cost-optimal heat production for three scenarios in combination of two heating demand levels. It is stated that no matter the geographically location of the site the cheapest resource should always be favorable as fuel, in the case when the same resource is viable at different sites a differentiated heat production is obtained. The supply temperature from each site is found to be the one lowest possible in order to serve all site-concerned end-users with a temperature level high enough for hot water production. The findings recommend a network temperatures reduction with the consequence in higher cost related to pumping work, but is lower than the savings due to the reduction in thermal losses.

    In order to provide the relocated part of the town with DH the hybrid evolutionary-MILP optimization routine is reshaped for finding different alternatives for network expansion layouts. The result is presented as a multi objective analysis between the operation cost and installation cost, showing the complete spectra of all optimal possible solutions and how the different cost correlate to each other. In this way, the outcome can be used for support in decision making, helping network owners is their planning and pipe sizing for new areas.

    For constructing the buildings that will populate the new city-area the Swedish government has stated a number of recommendations for achieving livable thermal indoor climate. An investigation is carried out analyzing the impact from the usage of three different heating system; air/air heat pump, air heating and floor heating in a low energy family house, where the first two system are aimed to use heat from the DH network. The analysis show that only the floor heating system satisfies the recommendations stated, but with carefully planning an air heating system could also fulfill the recommendations. Further, a techno-economical evaluation declares that the cheapest heating cost over 30 years is by using an air/air heat pump. In order to make DH competitive as heating source the needed price reduction is found for the hydronic floor and air heating system.

    Finally, three different building energy performance scenarios are studied in conjunction with the urban transformation in combination with the suggested energy measures from the Energy Performance certificates (EPC). In order to reach the national target entailing a reduction of 50% until 2050 all re-built buildings have to be built with passive standard and all advised measures in the EPC has to be carried out. Wort noticing is that the scenarios is analyzed as part of a 3-D City Model, which is found to be a worthwhile working tool for staff dealing with energy related issues.

  • 9.
    Vesterlund, Mattias
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Energy Science.
    District heating system analysis within the urban transformation of Kiruna2014Licentiate thesis, comprehensive summary (Other academic)
    Abstract [en]

    The urban transformation that is taking place in Kiruna, a Swedish town well above the Arctic Circle in the sub-arctic climate, is due to the ground deformation caused by iron ore mining and it is affecting all the infrastructures of the town. This thesis focuses on the studies about the district heating for the town of Kiruna. In the field of district heating it is important to have a good knowledge about network behavior, especially if network structure is meshed, in order to understand how the flow is distributed in each pipe within the network. This thesis describes the development of a method for the simulation of district heating networks that makes it possible to analyze and study complex networks with meshed structure, something that has not been possible before. The thermal losses for each pipe type are required as a fundamental input for the simulation. A fictitious pipe series has been created so that its loss matches the losses in the real network. It has been found that the created series is close to the series with the highest losses that is manufactured today. When redesigning the network structure to deal with the urban transformation, an investigation is performed regarding how new low energy building can be heated. This investigation shows that the only heating system that fulfills the guidelines stated by the Swedish authorities about indoor climate is the floor heating. A techno-economical evaluation shows that the cheapest heating technology is an air to air heat pump. In order to make district heating attractive as a heating source for house owners a vigorous price reduction is needed.

  • 10.
    Vesterlund, Mattias
    et al.
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Energy Science.
    Dahl, Jan
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Energy Science.
    A method for the simulation and optimization of district heating systems with meshed networks2015In: Energy Conversion and Management, ISSN 0196-8904, E-ISSN 1879-2227, Vol. 89, p. 555-567Article in journal (Refereed)
    Abstract [en]

    There are two main methods nowadays for modeling district heating systems, but a key disadvantage of both is that a real network containing loops cannot be described without artificial simplifications in order to eliminate those distinguishing features. However, loops are very common in mature networks that have developed a meshed structure, and make the distribution of mass and heat flows quite characteristic. For this reason, a new process integration method for modeling complex district heating systems containing loops is described in this paper. This method makes it possible to analyze how loops and bottlenecks affect the behavior of the network, as well as the distribution path of the thermal energy in it. The district heating system in the town of Kiruna (located in the north of Sweden) has a complex design with several loops and part of it is used in the paper as an example of application.

  • 11.
    Vesterlund, Mattias
    et al.
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Energy Science.
    Sandberg, Johan
    Luleå University of Technology, Department of Engineering Sciences and Mathematics.
    Lindblom, Bo
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Energy Science.
    Dahl, Jan
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Energy Science.
    A new method for modeling district heating systems2012Conference paper (Refereed)
    Abstract [en]

    Due to the mining of iron ore by the local mining industry (LKAB) a deformation zone is approaching the town of Kiruna, which is situated in the north of Sweden. The town is going through an urban transformation and parts of the town is about to be relocated. The relocating of the town is affecting all the infrastructure of the town, one of those is the district heating system. The aim of this paper is to apply a process integration method to study how the existing district heating system is behaving and to create a model for the whole district heating system.The district heating system in the town has a complex design with several loops. When dealing with modeling of a district heating system there are two methods that are most common, the Danish- and the German methods. These methods allow for simplification of the network shape, still with good accuracy in system behavior compared to real system behavior. A disadvantage with these two methods is that they cannot handle a district heating system that contains loops without making changes compared to the real physical system.A method that allows modeling of loops in the district heating system has been developed, using the remind-software. This method makes it possible to analyze how loops in the district heating system are behaving, without making physical changes when modeling the district heating system. The model will be used as a default model for redesigning the district heating system when moving the town. It will also be used to optimize heat deliveries from LKAB district heating system and for analyzing the possibility for seasonal storage of waste energy from LKAB and municipality energy company TVAB or how new heat production plants should optimized.In this paper the method is described and applied in order to model the whole present district heating system for the town.

  • 12.
    Vesterlund, Mattias
    et al.
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Energy Science.
    Sandberg, Johan
    Luleå University of Technology, Department of Engineering Sciences and Mathematics.
    Lindblom, Bo
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Energy Science.
    Dahl, Jan
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Energy Science.
    Evaluation of losses in district heating system, a case study2013Conference paper (Refereed)
    Abstract [en]

    To be able to create a model that accurately describes a district heating system, it is important to identify the thermal losses and how they are distributed. However, general methods targeting the determination of losses are scarce in the literature. In the current case the losses for a district heating system in Kiruna, a town in northern Sweden, has been estimated in the year 2010 to be 12%, which is in the range for a typical Swedish network. Unfortunately, detailed information of the thermal losses is lacking.In this paper two methods to determine loss distribution in a district heating system are presented.Two databases of pipe lengths and diameters have been compiled for two piping categories, loops and feeds. Any missing data regarding pipe diameters in the map has then been determined with the two different methods.In the first method average pipe diameters for loops and feeds are calculated. All pipes with unknown diameter are then assumed to have the average one. The second method considers a percentage based distribution of known diameters and assigns the same distribution to the missing pipe diameters. The losses were estimated in the whole system according to the data from a pipe producer catalogue, in which losses are calculated according to current European standard. The results show that the losses in the system are similar to the losses caused by pipes with the lowest insulating capacity.By using the two methods two fictitious pipe series reproducing exactly the losses in the system are created by scaling the calculated losses of the catalogue pipe series which would give the most similar losses (the one with the lowest insulating capacity). This adjustment was +3.1% by using the first method, and +4.9% by using the second method.The major conclusion of this study is that, both methods can be used for calculating the distribution of thermal losses in the district heating system of Kiruna; moreover, this kind of analysis can be an important tool for analyzing investments in the district heating network in Kiruna.

  • 13.
    Vesterlund, Mattias
    et al.
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Energy Science.
    Toffolo, Andrea
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Energy Science.
    Design optimization of a district heating network expansion: a case study for the town of Kiruna2017In: Applied Sciences, E-ISSN 2076-3417, Vol. 7, no 5, article id 488Article in journal (Refereed)
    Abstract [en]

    The urbanization of new areas beyond the existing perimeter of a town implies the expansion of several infrastructures, including the district heating network. The main variables involved in the design of the district heating network expansion are the layout of the new pipes, their diameters, and the capacity of the new heat production sites that are required to satisfy the increased demand of room heating and hot tap water. In this paper, a multi-objective evolutionary algorithm is applied to the minimization of the costs related to the expansion of the district heating network of the town of Kiruna, in northern Sweden. The results show that the spectrum of the optimal design compromises between investment costs for the new pipes and the new heat generation site on one side, and operating costs due to overall fuel consumption and pumping power in the network on the other. The presented methodology is a tool meant for the decision makers in the company who own the district heating network, to evaluate all the possible best design alternatives before making a decision.

  • 14.
    Vesterlund, Mattias
    et al.
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Energy Science.
    Toffolo, Andrea
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Energy Science.
    Dahl, Jan
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Energy Science.
    Optimization of multi-source complex district heating network: a case study2016In: Proceeding of 29th International Conference on efficiency, Cost, Optimization, Simulation and Enviromental Impact of Energy Systems, 2016Conference paper (Refereed)
    Abstract [en]

    The level of complexity for a district heating network increases with the maturity of the network, and this affects the pattern of the distribution of the hot water from the heat production sites to the end users. The majority of district heating systems are also multi-source networks, typically supported with heat from one main production site and other smaller satellite sites that are activated when required. In general, local energy companies have a lack of knowledge regarding how a meshed network behaves when different production sites are operated. The schedule of heat generation at the different sites is often based on staff experience and some general rules of thumb.

    In this paper a method for modeling and simulating complex district networks is further developed in order to optimize the total operating costs of a multi-source network, with constraints on the pressure and temperature levels in the user areas and on the heat generation characteristics at each production site.

    The optimization results show that the usage of the cheapest resources is preferred to a distributed generation of heat, even if some of the pipes may exceed the recommended thermal load capacity. The main site water supply temperature is found to be the lowest allowed by the constraint on the temperature of the water supplied to the end users, since the decrease of the costs associated with the lower thermal losses in the network is not counterbalanced by the increase of those associated with the pumping power of a larger water mass flow rate.

  • 15.
    Vesterlund, Mattias
    et al.
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Energy Science.
    Toffolo, Andrea
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Energy Science.
    Dahl, Jan
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Energy Science.
    Optimization of multi-source complex district heating network, a case study2017In: Energy, ISSN 0360-5442, E-ISSN 1873-6785, Vol. 126, p. 53-63Article in journal (Refereed)
    Abstract [en]

    The level of complexity for a district heating network increases with the maturity of the network, and this affects the pattern of the distribution of the hot water from the heat production sites to the end users. The majority of district heating systems are also multi-source networks, typically supported with heat from one main production site and other smaller satellite sites that are activated when required. In general, local energy companies have a lack of knowledge regarding how a meshed network behaves when different production sites are operated. The schedule of heat generation at the different sites is often based on staff experience and some general rules of thumb.

    In this paper a method for modeling and simulating complex district networks is further developed in order to optimize the total operating costs of a multi-source network, with constraints on the pressure and temperature levels in the user areas and on the heat generation characteristics at each production site.

    The optimization results show that the usage of the cheapest resources is preferred to a distributed generation of heat, even if some of the pipes may exceed the recommended thermal load capacity. The main site water supply temperature is found to be the lowest allowed by the constraint on the temperature of the water supplied to the end users, since the decrease of the costs associated with the lower thermal losses in the network is not counterbalanced by the increase of those associated with the pumping power of a larger water mass flow rate.

  • 16.
    Vesterlund, Mattias
    et al.
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Energy Science.
    Toffolo, Andrea
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Energy Science.
    Dahl, Jan
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Energy Science.
    Simulation and analysis of a meshed district heating network2015In: ECOS 2015: 28th International Conference on Efficiency, Cost, Optimization, Simulation and Environmental Impact of Energy Systems, International Conference on Efficiency, Cost, Optimization, Simulation and Environmental Impact of Energy Systems , 2015Conference paper (Refereed)
  • 17.
    Vesterlund, Mattias
    et al.
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Energy Science.
    Toffolo, Andrea
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Energy Science.
    Dahl, Jan
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Energy Science.
    Simulation and analysis of a meshed district heating network2016In: Energy Conversion and Management, ISSN 0196-8904, E-ISSN 1879-2227, Vol. 122, p. 63-73Article in journal (Refereed)
    Abstract [en]

    The flow distribution in a district heating network tends to become no longer obvious when system design is developed and its complexity increased. As a consequence, the network owner, often the local energy company, is in need of a simulation program to have the possibility of analysing network behaviour and expand the understanding about the operation of district heating system. In this paper, a simulation tool developed in MATLAB/Simulink is applied in order to analyse the flow distribution in the district heating network of the town of Kiruna (Sweden). The network in Kiruna has been developing since the 60s and is today a complex network with a meshed structure, i.e. it is formed by a set of loops from which secondary branches depart. The simulation tool is part of a methodology that has specifically been developed to analyse the flow pattern in such kind of networks without altering their physical structure, and it is expected to be a valuable tool for the redesign of the network in the forthcoming relocation of some of the urban districts. The results about the current network configuration show that only a few pipes in the network are exceeding the levels of heat flow recommended by pipe manufacturers. The largest drops in pressure and temperature from the heat production site to the nodes serving the main consumer areas are within 1.2 bar and 9 °C in the days of highest demand.

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